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Sample records for degradation processes occur

  1. Inhibition and kinetic studies of lignin degrading enzymes of Ganoderma boninense by naturally occurring phenolic compounds.

    Science.gov (United States)

    Surendran, Arthy; Siddiqui, Yasmeen; Saud, Halimi Mohd; Ali, Nusaibah Syd; Manickam, Sivakumar

    2018-05-22

    Lignolytic (Lignin degrading) enzyme, from oil palm pathogen Ganoderma boninense Pat. (Syn G. orbiforme (Ryvarden), is involved in the detoxification and the degradation of lignin in the oil palm and is the rate-limiting step in the infection process of this fungus. Active inhibition of lignin degrading enzymes secreted by G. boninense by various naturally occurring phenolic compounds and estimation of efficiency on pathogen suppression was aimed at. In our work, ten naturally occurring phenolic compounds were evaluated for their inhibitory potential towards the lignolytic enzymes of G.boninense. Additionally, the lignin degrading enzymes were characterised. Most of the peholic compounds exhibited an uncompetitive inhibition towards the lignin degrading enzymes. Benzoic acid was the superior inhibitor to the production of lignin degrading enzymes, when compared between the ten phenolic compounds. The inhibitory potential of the phenolic compounds toward the lignin degrading enzymes are higher than that of the conventional metal ion inhibitor. The lignin degrading enzymes were stable in a wide range of pH but were sensitive to higher to temperature. The study demonstrated the inhibitor potential of ten naturally occurring phenolic compounds toward the lignin degrading enzymes of G. boninense with different efficacies. The study has shed a light towards a new management strategy to control BSR in oil palm. It serves as replacement for the existing chemical control. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. Mechanical degradation processes: The Belgian experience

    International Nuclear Information System (INIS)

    Lafaille, J.P.; Hennart, J.C.

    1998-01-01

    Design life is merely used in Belgium as a requirement in the 'Design Specification' of some components subjected to known degradation processes, such as stress induced fatigue, embrittlement (irradiation or other), various types of corrosion, wear, erosion, thermal aging (electrical insulation, ...), etc. Design life is in no way directly related to the duration of the plant operation. In that sense design life for the Belgian NPP components includes the values of 20, 30 and 40 years. The oldest plant (20 years design life) has been decommissioned in 1991. The most recent units (40 years design life) have still a good time to go. The intermediate units (30 years design life) started around 1975. Consequently components of these plants need be looked at to determine whether or not deteriorations have occurred. The paper presents the various known mechanical degradation processes and how they affect various components. Emphasis is laid on prevention, mitigation or repair measures that have been or are being taken to avoid that the 'Equipment design life' be the limiting factor in the duration of the plant operation. (author)

  3. Soil physical land degradation processes

    Science.gov (United States)

    Horn, Rainer

    2017-04-01

    According to the European Soil Framework Directive (2006) soil compaction is besides water and wind erosion one of the main physical reasons and threats of soil degradation. It is estimated, that 32% of the subsoils in Europe are highly degraded and 18% moderately vulnerable to compaction. The problem is not limited to crop land or forest areas (especially because of non-site adjusted harvesting machines) but is also prevalent in rangelands and grassland, and even in so called natural non-disturbed systems. The main reasons for an intense increase in compacted agricultural or forested regions are the still increasing masses of the machines as well the increased frequency of wheeling under non favorable site conditions. Shear and vibration induced soil deformation enhances the deterioration of soil properties especially if the soil water content is very high and the internal soil strength very low. The same is true for animal trampling in combination with overgrazing of moist to wet pastures which subsequently causes a denser (i.e. reduced proportion of coarse pores with smaller continuity) but still structured soil horizons and will finally end in a compacted platy structure. In combination with high water content and shearing due to trampling therefore results in a complete muddy homogeneous soil with no structure at all. (Krümmelbein et al. 2013) Site managements of arable, forestry or horticulture soils requires a sufficiently rigid pore system which guarantees water, gas and heat exchange, nutrient transport and adsorption as well as an optimal rootability in order to avoid subsoil compaction. Such pore system also guarantees a sufficient microbial activity and composition in order to also decompose the plant etc. debris. It is therefore essential that well structured horizons dominate in soils with at best subangular blocky structure or in the top A- horizons a crumbly structure due to biological activity. In contrast defines the formation of a platy

  4. ESR studies on degradation processes in polyethyleneterephtalate

    International Nuclear Information System (INIS)

    Chipara, M.; Chipara, M.D.; Georgescu, L.; Constantinescu, L.; Morosanu, C.

    2002-01-01

    Complete text of publication follows. The generation of free radicals by degradation processes (thermal, plasma and radiation induced) is analyzed. Details regarding the generation of free radicals, their interactions, and kinetics, as revealed by electron spin resonance (ESR), with emphasis on laser beam degradation, are discussed. Some ESR lines of laser-irradiated polyethyleneterephtalate (PET), recorded at room temperature, are shown in Figure 1. The lines are narrow singlets located around g=2.003. The resonance line amplitude, width and double integral of the resonance line are affected by the power of the incident beam. The common features of these degradation processes (universal behavior) as well as the fingerprints of each degradation process are analyzed in detail

  5. North American Soil Degradation: Processes, Practices, and Mitigating Strategies

    Directory of Open Access Journals (Sweden)

    R. L. Baumhardt

    2015-03-01

    Full Text Available Soil can be degraded by several natural or human-mediated processes, including wind, water, or tillage erosion, and formation of undesirable physical, chemical, or biological properties due to industrialization or use of inappropriate farming practices. Soil degradation occurs whenever these processes supersede natural soil regeneration and, generally, reflects unsustainable resource management that is global in scope and compromises world food security. In North America, soil degradation preceded the catastrophic wind erosion associated with the dust bowl during the 1930s, but that event provided the impetus to improve management of soils degraded by both wind and water erosion. Chemical degradation due to site specific industrial processing and mine spoil contamination began to be addressed during the latter half of the 20th century primarily through point-source water quality concerns, but soil chemical degradation and contamination of surface and subsurface water due to on-farm non-point pesticide and nutrient management practices generally remains unresolved. Remediation or prevention of soil degradation requires integrated management solutions that, for agricultural soils, include using cover crops or crop residue management to reduce raindrop impact, maintain higher infiltration rates, increase soil water storage, and ultimately increase crop production. By increasing plant biomass, and potentially soil organic carbon (SOC concentrations, soil degradation can be mitigated by stabilizing soil aggregates, improving soil structure, enhancing air and water exchange, increasing nutrient cycling, and promoting greater soil biological activity.

  6. IMPORTANT DEGRADATIONS IN POLYETHYLENE TERAPHTALATE EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Şule ALTUN

    2003-01-01

    Full Text Available Polyethylene terephthalate (PET is one of the most used thermo-plastic polymers. The total consumption of PET has been about 30 million tons in the year 2000. Polyester fibers constitute about 60 % of total synthetic fibers consumption. During extrusion, PET polymer is faced to thermal, thermo-oxidative and hydrolytic degradation, which result in severe reduction in its molecular weight, thereby adversely affecting its subsequent melt processability. Therefore, it is essential to understand degradation processes of PET during melt extrusion.

  7. Fluorescence monitoring of ultrasound degradation processes

    International Nuclear Information System (INIS)

    Hassoon, Salah; Bulatov, Valery; Yasman, Yakov; Schechter, Israel

    2004-01-01

    Ultrasound-based water treatment is often applied for degradation of stable organic pollutants, such as polycyclic aromatic hydrocarbons and halogenated compounds. Monitoring the degradation process, during the application of ultrasound radiation, is of considerable economical interest. In this work, the possibility of performing on-line spectral analysis during sonication was examined and it was found that direct absorption or fluorescence readings are misleading. Optical monitoring is strongly affected by the absorption and scattering of light by cavitation micro-bubbles and ultrasound induced particulates. A model was developed to account for these effects and to allow for on-line fluorescence analysis. The model takes into account the absorption and scattering coefficients of the micro-bubbles and particulates, as well as their time dependent concentration. The model parameters are found from independent measurements where the pollutants are added to already sonicated pure water. Then, the model is tested for predicting the actual fluorescence behavior during the sonication process. It has been shown that the model allows for recovery of the true degradation data, as obtained by off-line HPLC measurements

  8. A condition-based maintenance of a dependent degradation-threshold-shock model in a system with multiple degradation processes

    International Nuclear Information System (INIS)

    Caballé, N.C.; Castro, I.T.; Pérez, C.J.; Lanza-Gutiérrez, J.M.

    2015-01-01

    This paper proposes a condition-based maintenance strategy for a system subject to two dependent causes of failure: degradation and sudden shocks. The internal degradation is reflected by the presence of multiple degradation processes in the system. Degradation processes start at random times following a Non-homogeneous Poisson process and their growths are modelled by using a gamma process. When the deterioration level of a degradation process exceeds a predetermined value, we assume that a degradation failure occurs. Furthermore, the system is subject to sudden shocks that arrive at the system following a Doubly Stochastic Poisson Process. A sudden shock provokes the total breakdown of the system. Thus, the state of the system is evaluated at inspection times and different maintenance tasks can be carried out. If the system is still working at an inspection time, a preventive maintenance task is performed if the deterioration level of a degradation process exceeds a certain threshold. A corrective maintenance task is performed if the system is down at an inspection time. A preventive (corrective) maintenance task implies the replacement of the system by a new one. Under this maintenance strategy, the expected cost rate function is obtained. A numerical example illustrates the analytical results. - Highlights: • A condition-based maintenance model is proposed. • Two dependent causes of failure are considered: deterioration and external shocks. • Deterioration is given by multiple degradation processes growing by a gamma process. • The initiation of degradation processes follows a Non-homogeneous Poisson process. • External shocks arrive at the system by using a Doubly Stochastic Poisson Process

  9. Physicochemical processes occurring under action of ionizing radiation in sarcophagus

    International Nuclear Information System (INIS)

    Azarov, S.I.; Pshenichny, V.A.; Vilenskaya, L.N.; Korchevnaya, O.V.; Martseniuk, L.S.

    1998-01-01

    The result of analysis of environment ionization process inside Sarcophagus owing to alpha-, beta- and gamma-radiation processes with forming of ions. It is shown that as a result of ionization and physicochemical transformations gaseous mixtures, which are dangerous for personnel's health and can influence upon general technical safety of Sarcophagus, can release into atmosphere

  10. [Description of the mental processes occurring during clinical reasoning].

    Science.gov (United States)

    Pottier, P; Planchon, B

    2011-06-01

    Clinical reasoning is a highly complex system with multiple inter-dependent mental activities. Gaining a better understanding of those cognitive processes has two practical implications: for physicians, being able to analyse their own reasoning method may prove to be helpful in diagnostic dead end; for medical teachers, identifying problem-solving strategies used by medical students may foster an appropriate individual feed-back aiming at improving their clinical reasoning skills. On the basis of a detailed literature review, the main diagnostic strategies and their related pattern of mental processes are described and illustrated with a concrete example, going from the patient's complaint to the chosen solution. Inductive, abductive and deductive diagnostic approaches are detailed. Different strategies for collecting data (exhaustive or oriented) and for problem-building are described. The place of problem solving strategies such as pattern-recognition, scheme inductive process, using of clinical script, syndrome grouping and mental hypotheses test is considered. This work aims at breaking up mental activities in process within clinical reasoning reminding that expert reasoning is characterised by the ability to use and structure the whole of these activities in a coherent system, using combined strategies in order to guarantee a better accuracy of their diagnosis. Copyright © 2010 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  11. A General Accelerated Degradation Model Based on the Wiener Process.

    Science.gov (United States)

    Liu, Le; Li, Xiaoyang; Sun, Fuqiang; Wang, Ning

    2016-12-06

    Accelerated degradation testing (ADT) is an efficient tool to conduct material service reliability and safety evaluations by analyzing performance degradation data. Traditional stochastic process models are mainly for linear or linearization degradation paths. However, those methods are not applicable for the situations where the degradation processes cannot be linearized. Hence, in this paper, a general ADT model based on the Wiener process is proposed to solve the problem for accelerated degradation data analysis. The general model can consider the unit-to-unit variation and temporal variation of the degradation process, and is suitable for both linear and nonlinear ADT analyses with single or multiple acceleration variables. The statistical inference is given to estimate the unknown parameters in both constant stress and step stress ADT. The simulation example and two real applications demonstrate that the proposed method can yield reliable lifetime evaluation results compared with the existing linear and time-scale transformation Wiener processes in both linear and nonlinear ADT analyses.

  12. Modelling and estimating degradation processes with application in structural reliability

    International Nuclear Information System (INIS)

    Chiquet, J.

    2007-06-01

    The characteristic level of degradation of a given structure is modeled through a stochastic process called the degradation process. The random evolution of the degradation process is governed by a differential system with Markovian environment. We put the associated reliability framework by considering the failure of the structure once the degradation process reaches a critical threshold. A closed form solution of the reliability function is obtained thanks to Markov renewal theory. Then, we build an estimation methodology for the parameters of the stochastic processes involved. The estimation methods and the theoretical results, as well as the associated numerical algorithms, are validated on simulated data sets. Our method is applied to the modelling of a real degradation mechanism, known as crack growth, for which an experimental data set is considered. (authors)

  13. Degradation of triketone herbicides, mesotrione and sulcotrione, using advanced oxidation processes

    International Nuclear Information System (INIS)

    Jović, Milica; Manojlović, Dragan; Stanković, Dalibor; Dojčinović, Biljana; Obradović, Bratislav; Gašić, Uroš; Roglić, Goran

    2013-01-01

    Highlights: • Thirteen products are identified during all degradations for both pesticides. • In all degradations same products and mechanism was observed for both pesticides. • Dominant mechanism for all degradations starts with attack on the carbonyl group. • Only in ozone and DBD degradation one product is formed in radical reaction. • Only in Fenton degradation opening of benzene ring occurs. -- Abstract: Degradation of two triketone herbicides, mesotrione and sulcotrione, was studied using four different advanced oxidation processes (AOPs): ozonization, dielectric barrier discharge (DBD reactor), photocatalysis and Fenton reagent, in order to find differences in mechanism of degradation. Degradation products were identified by high performance liquid chromatography (HPLC–DAD) and UHPLC–Orbitrap–MS analyses. A simple mechanism of degradation for different AOP was proposed. Thirteen products were identified during all degradations for both pesticides. It was assumed that the oxidation mechanisms in the all four technologies were not based only on the production and use of the hydroxyl radical, but they also included other kinds of oxidation mechanisms specific for each technology. Similarity was observed between degradation mechanism of ozonation and DBD. The greatest difference in the products was found in Fenton degradation which included the opening of benzene ring. When degraded with same AOP pesticides gave at the end of treatment the same products. Global toxicity and COD value of samples was determined after all degradations. Real water sample was used to study influence of organic matter on pesticide degradation. These results could lead to accurate estimates of the overall effects of triketone herbicides on environmental ecosystems and also contributed to the development of improved removal processes

  14. Influence of Poly(ethylene glycol) Degradation on Voiding Sporadically Occurring in Solder Joints with Electroplated Cu

    Science.gov (United States)

    Wafula, F.; Yin, L.; Borgesen, P.; Andala, D.; Dimitrov, N.

    2012-07-01

    This paper presents a comprehensive study of the effect of poly(ethylene glycol) (PEG) degradation on the void formation known to take place sporadically at the interface between electroplated Cu and Pb-free solder. Thorough chemical analysis of our plating solution, carried out at different times of the deposition process by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy, reveals a dramatic shift in the peaks to lower mass range with time. Scanning electron microscopy cross-sectional images of solder joints with Cu samples that have been plated at different times in the course of solution aging show a decrease in void formation. A decreasing magnitude of the deposition overpotential also seen during aging suggests that, breaking down to lower-molecular-weight fragments, PEG loses its suppression effect and likely has lower impact on the voiding propensity. This indirect correlation is confirmed further by the use of plating solutions containing PEG with preselected molecular weight. We also report on the effect of the surface area-to-solution volume ratio on PEG degradation studied by comparative experiments performed in a 50-mL bath with a rotating disc electrode and in a larger cell (Hull cell) with volume of 267 mL. The results show that, at fixed charge per unit volume, PEG degrades at a greatly accelerated rate in the Hull cell featuring higher electrode surface-to-solution volume ratio. Analysis of solder joints with accordingly grown Cu layers suggests that the voiding decreases faster with the accelerated rate of PEG degradation.

  15. Degradation of diclofenac by UV-activated persulfate process: Kinetic studies, degradation pathways and toxicity assessments.

    Science.gov (United States)

    Lu, Xian; Shao, Yisheng; Gao, Naiyun; Chen, Juxiang; Zhang, Yansen; Xiang, Huiming; Guo, Youluo

    2017-07-01

    Diclofenac (DCF) is the frequently detected non-steroidal pharmaceuticals in the aquatic environment. In this study, the degradation of DCF was evaluated by UV-254nm activated persulfate (UV/PS). The degradation of DCF followed the pseudo first-order kinetics pattern. The degradation rate constant (k obs ) was accelerated by UV/PS compared to UV alone and PS alone. Increasing the initial PS dosage or solution pH significantly enhanced the degradation efficiency. Presence of various natural water constituents had different effects on DCF degradation, with an enhancement or inhibition in the presence of inorganic anions (HCO 3 - or Cl - ) and a significant inhibition in the presence of NOM. In addition, preliminary degradation mechanisms and major products were elucidated using LC-MS/MS. Hydroxylation, decarbonylation, ring-opening and cyclation reaction involving the attack of SO 4 • - or other substances, were the main degradation mechanism. TOC analyzer and Microtox bioassay were employed to evaluate the mineralization and cytotoxicity of solutions treated by UV/PS at different times, respectively. Limited elimination of TOC (32%) was observed during the mineralization of DCF. More toxic degradation products and their related intermediate species were formed, and the UV/PS process was suitable for removing the toxicity. Of note, longer degradation time may be considered for the final toxicity removal. Copyright © 2017. Published by Elsevier Inc.

  16. Predicting where enhanced atrazine degradation will occur based on soil pH and herbicide use history

    Science.gov (United States)

    Soil bacteria on all continents except Antartica have developed the ability to rapidly degrade the herbicide atrazine, a phenomenon referred to as enhanced degradation. The agronomic significance of enhanced degradation is the potential for reduced residual weed control with atrazine in Corn, Sorgh...

  17. Optimization of process variables for the microbial degradation of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... The optimum process conditions for maximizing phenol degradation (removal) ... cellular maintenance requirements on temperature makes it an important ..... the International Foundation for Science (IFS) for the financial ...

  18. Fault Management: Degradation Signature Detection, Modeling, and Processing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Fault to Failure Progression (FFP) signature modeling and processing is a new method for applying condition-based signal data to detect degradation, to identify...

  19. A General Accelerated Degradation Model Based on the Wiener Process

    Directory of Open Access Journals (Sweden)

    Le Liu

    2016-12-01

    Full Text Available Accelerated degradation testing (ADT is an efficient tool to conduct material service reliability and safety evaluations by analyzing performance degradation data. Traditional stochastic process models are mainly for linear or linearization degradation paths. However, those methods are not applicable for the situations where the degradation processes cannot be linearized. Hence, in this paper, a general ADT model based on the Wiener process is proposed to solve the problem for accelerated degradation data analysis. The general model can consider the unit-to-unit variation and temporal variation of the degradation process, and is suitable for both linear and nonlinear ADT analyses with single or multiple acceleration variables. The statistical inference is given to estimate the unknown parameters in both constant stress and step stress ADT. The simulation example and two real applications demonstrate that the proposed method can yield reliable lifetime evaluation results compared with the existing linear and time-scale transformation Wiener processes in both linear and nonlinear ADT analyses.

  20. The nature and position of processing determines why forgetting occurs in working memory tasks.

    Science.gov (United States)

    Jarrold, Christopher; Tam, Helen; Baddeley, Alan D; Harvey, Caroline E

    2010-12-01

    The effect of potentially distracting processing within working memory was examined by varying the nature and position of processing across conditions of a Brown-Peterson-like task. Separate groups of participants carried out verbal or visuospatial processing operations on identical stimuli, while retaining lists of to-be-remembered words. The number of words presented either before or after the processing interval was varied systematically. Results showed that although verbal processing was no more demanding than visuospatial processing, it led to greater forgetting. However, forgetting was confined to items presented prior to processing, and the difference in degree of forgetting shown by the two groups was maximal when four items occurred before processing. Temporal isolation effects were more marked in the verbal processing group. These findings indicate that individuals can keep active a limited number of items in primary memory during processing, unless processing blocks rehearsal, in which case retrieval occurs from secondary memory.

  1. Soil Degradation Processes; Procesos de Degradacion del Suelo

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Crespi, S; Perez Martinez, M; Cuesta Santianes, M J; Cabrera Jimenez, J A

    2007-12-28

    In the European communication entitled Towards a Thematic Strategy for Soil Protection, eight main threats to soil were identified: contamination, erosion, loss of organic matter, compaction, salinization; hydro-geological risks, soil sealing, and decline in biodiversity. The main purpose of this report is to provide the current state of knowledge of the soil degradation processes both, in the European Community scale and, particularly, in the Spanish territory. Furthermore, the main research project information related to soil degradation processes is also included, identifying the main actors involved in soil scientific research and development. (Author) 66 refs.

  2. Influence of compatibilizer on blends degradation during processing

    Directory of Open Access Journals (Sweden)

    Walter R. Waldman

    2013-01-01

    Full Text Available The thermomechanical degradation of blends made from polypropylene and polystyrene, with or without compatibilizer, was studied using an internal mixer coupled to a torque rheometer. The blends processed without compatibilizer presented regular and expected results regarding torque reduction, with evidence of chain scission. The blends processed with the block copolymer of styrene and butadiene, SBS, as a compatibilizer presented unchanged or less reduced variation on torque values during processing. The extraction of stabilizers from the compatibilizer before processing did not affect the results. The compatibilizer concentration in the blends was varied, with its influence still being observed in concentrations as low as 0.03 parts per hundred. Similar results were obtained in an experiment comparing the performance of a primary commercial anti-oxidant, Irganox 1076, and the compatibilizer SBS. Therefore, the compatibilizer can be considered as a processing aid agent with positive influence on avoiding thermomechanical degradation.

  3. Degradation of plant wastes by anaerobic process using rumen bacteria.

    Science.gov (United States)

    Seon, J; Creuly, C; Duchez, D; Pons, A; Dussap, C G

    2003-01-01

    An operational reactor has been designed for the fermentation of a pure culture of Fibrobacter succinogenes with the constraints of strict anaerobic condition. The process is controlled by measurements of pH, redox, temperature and CO2 pressure; it allows an efficient degradation (67%) of lignocellulosic wastes such as a mixture of wheat straw, soya bean cake and green cabbage.

  4. Iodinated contrast media electro-degradation: process performance and degradation pathways.

    Science.gov (United States)

    Del Moro, Guido; Pastore, Carlo; Di Iaconi, Claudio; Mascolo, Giuseppe

    2015-02-15

    The electrochemical degradation of six of the most widely used iodinated contrast media was investigated. Batch experiments were performed under constant current conditions using two DSA® electrodes (titanium coated with a proprietary and patented mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum). The degradation removal never fell below 85% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) when perchlorate was used as the supporting electrolyte; however, when sulphate was used, the degradation performance was above 80% (at a current density of 64 mA/cm(2) with a reaction time of 150 min) for all of the compounds studied. Three main degradation pathways were identified, namely, the reductive de-iodination of the aromatic ring, the reduction of alkyl aromatic amides to simple amides and the de-acylation of N-aromatic amides to produce aromatic amines. However, as amidotrizoate is an aromatic carboxylate, this is added via the decarboxylation reaction. The investigation did not reveal toxicity except for the lower current density used, which has shown a modest toxicity, most likely for some reaction intermediates that are not further degraded. In order to obtain total removal of the contrast media, it was necessary to employ a current intensity between 118 and 182 mA/cm(2) with energy consumption higher than 370 kWh/m(3). Overall, the electrochemical degradation was revealed to be a reliable process for the treatment of iodinated contrast media that can be found in contaminated waters such as hospital wastewater or pharmaceutical waste-contaminated streams. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Various processes occurring in strong interactions between heavy ions: Compound nucleus formation, incomplete fusion, and quasifission

    International Nuclear Information System (INIS)

    Lefort, M.

    1975-01-01

    This paper deals with the problem of various deep processes occurring when two complex nuclei enter in collision. It is suggested that very deep inelastic processes may lead to either a compound nucleus or a composite system which shortly decays into two fission fragments (quasifission process). Particularly for heavy projectiles and targets, the predominant Coulomb potential inhibits the compound nucleus formation for low l waves. Then a critical angular momentum can be defined as the limit below which both processes (quasifission and compound nucleus formation) occur. For the heaviest nuclei, nearly all l waves below l) contribute to the quasifission phenomenon

  6. Water and processes of degradation in the Martian landscape

    Science.gov (United States)

    Milton, D. J.

    1973-01-01

    It is shown that erosion has been active on Mars so that many of the surface landforms are products of degradation. Unlike earth, erosion has not been a universal process, but one areally restricted and intermittently active so that a landscape is the product of one or two cycles of erosion and large areas of essentially undisturbed primitive terrain; running water has been the principal agent of degradation. Many features on Mars are most easily explained by assuming running surface water at some time in the past; for a few features, running water is the only possible explanation.

  7. Chemical and radiolytical solvent degradation in the Purex process

    International Nuclear Information System (INIS)

    Stieglitz, L.; Becker, R.

    1985-01-01

    The state of the art of chemical and radiolytical solvent degradation is described. For the hydrolysis of tributylphosphate TBP->HDBP->H 2 MBP->H 3 PO 4 values are given for the individual constants in a temperature range from 23 to 90 0 C. Radiolytic yields were measured for HDBP as 80 mg/Wh, for H 2 MBP as 2 mg/Wh, and for H 3 PO 4 as 5 mg/Wh. Experimental results on the degradation products of the diluent are summarized and their influence on the process is discussed. Long chain acid phosphates and acid TBP oligomeres were identified as responsible for the retention of fission products. Techniques such as polarography, infrared spectrometry and electrolytic conductometry are applied to estimate concentrations of degradation products down to 10 -5 mol/l. (orig.) [de

  8. Chemical and radiolytical solvent degradation in the Purex process

    Energy Technology Data Exchange (ETDEWEB)

    Stieglitz, L; Becker, R

    1985-01-01

    The state of the art of chemical and radiolytical solvent degradation is described. For the hydrolysis of tributylphosphate TBP->HDBP->H/sub 2/MBP->H/sub 3/PO/sub 4/ values are given for the individual constants in a temperature range from 23 to 90/sup 0/C. Radiolytic yields were measured for HDBP as 80 mg/Wh, for H/sub 2/MBP as 2 mg/Wh, and for H/sub 3/PO/sub 4/ as 5 mg/Wh. Experimental results on the degradation products of the diluent are summarized and their influence on the process is discussed. Long chain acid phosphates and acid TBP oligomeres were identified as responsible for the retention of fission products. Techniques such as polarography, infrared spectrometry and electrolytic conductometry are applied to estimate concentrations of degradation products down to 10/sup -5/ mol/l.

  9. Degradation of malachite green in aqueous solution by Fenton process.

    Science.gov (United States)

    Hameed, B H; Lee, T W

    2009-05-30

    In this study, advanced oxidation process utilizing Fenton's reagent was investigated for degradation of malachite green (MG). The effects of different reaction parameters such as the initial MG concentration, initial pH, the initial hydrogen peroxide concentration, the initial ferrous concentration and the reaction temperature on the oxidative degradation of MG have been investigated. The optimal reacting conditions were experimentally found to be pH 3.40, initial hydrogen peroxide concentration=0.50mM and initial ferrous concentration=0.10mM for initial MG concentration of 20mg/L at 30 degrees C. Under optimal conditions, 99.25% degradation efficiency of dye in aqueous solution was achieved after 60 min of reaction.

  10. Fate of products of degradation processes: consequences for climatic change

    International Nuclear Information System (INIS)

    Slanina, J.; Brink, H.M. ten; Khlystov, A.

    1999-01-01

    The end products of atmospheric degradation are not only CO 2 and H 2 O but also sulfate and nitrate depending on the chemical composition of the substances which are subject to degradation processes. Atmospheric degradation has thus a direct influence on the radiative balance of the earth not only due to formation of greenhouse gases but also of aerosols. Aerosols of a diameter of 0.1 to 2 micrometer, reflect short wave sunlight very efficiently leading to a radiative forcing which is estimated to be about -0.8 watt per m 2 by IPCC. Aerosols also influence the radiative balance by way of cloud formation. If more aerosols are present, clouds are formed with more and smaller droplets and these clouds have a higher albedo and are more stable compared to clouds with larger droplets. Not only sulfate, but also nitrate and polar organic compounds, formed as intermediates in degradation processes, contribute to this direct and indirect aerosol effect. Estimates for the Netherlands indicate a direct effect of -4 watt m -2 and an indirect effect of as large as -5 watt m -2 . About one third is caused by sulfates, one third by nitrates and last third by polar organic compounds. This large radiative forcing is obviously non-uniform and depends on local conditions. (author)

  11. A Polymorphism in the Processing Body Component Ge-1 Controls Resistance to a Naturally Occurring Rhabdovirus in Drosophila.

    Directory of Open Access Journals (Sweden)

    Chuan Cao

    2016-01-01

    Full Text Available Hosts encounter an ever-changing array of pathogens, so there is continual selection for novel ways to resist infection. A powerful way to understand how hosts evolve resistance is to identify the genes that cause variation in susceptibility to infection. Using high-resolution genetic mapping we have identified a naturally occurring polymorphism in a gene called Ge-1 that makes Drosophila melanogaster highly resistant to its natural pathogen Drosophila melanogaster sigma virus (DMelSV. By modifying the sequence of the gene in transgenic flies, we identified a 26 amino acid deletion in the serine-rich linker region of Ge-1 that is causing the resistance. Knocking down the expression of the susceptible allele leads to a decrease in viral titre in infected flies, indicating that Ge-1 is an existing restriction factor whose antiviral effects have been increased by the deletion. Ge-1 plays a central role in RNA degradation and the formation of processing bodies (P bodies. A key effector in antiviral immunity, the RNAi induced silencing complex (RISC, localises to P bodies, but we found that Ge-1-based resistance is not dependent on the small interfering RNA (siRNA pathway. However, we found that Decapping protein 1 (DCP1 protects flies against sigma virus. This protein interacts with Ge-1 and commits mRNA for degradation by removing the 5' cap, suggesting that resistance may rely on this RNA degradation pathway. The serine-rich linker domain of Ge-1 has experienced strong selection during the evolution of Drosophila, suggesting that this gene may be under long-term selection by viruses. These findings demonstrate that studying naturally occurring polymorphisms that increase resistance to infections enables us to identify novel forms of antiviral defence, and support a pattern of major effect polymorphisms controlling resistance to viruses in Drosophila.

  12. Controlling of degradation effects in radiation processing of polymers

    International Nuclear Information System (INIS)

    2009-05-01

    The interest of Member States of the IAEA in introducing radiation technology into the polymer and plastics industry is growing. This publication summarizes a number of studies conducted in the framework of a coordinated research project (CRP) on controlling of degradation effects on polymers by radiation processing technologies. It reviews a variety of applications and details the most important results and achievements of the participating centres and laboratories during the course of the CRP. The publication is intended to be of use to scientists implementing the technology and managers of radiation processing facilities

  13. Corrected simulations for one-dimensional diffusion processes with naturally occurring boundaries.

    Science.gov (United States)

    Shafiey, Hassan; Gan, Xinjun; Waxman, David

    2017-11-01

    To simulate a diffusion process, a usual approach is to discretize the time in the associated stochastic differential equation. This is the approach used in the Euler method. In the present work we consider a one-dimensional diffusion process where the terms occurring, within the stochastic differential equation, prevent the process entering a region. The outcome is a naturally occurring boundary (which may be absorbing or reflecting). A complication occurs in a simulation of this situation. The term involving a random variable, within the discretized stochastic differential equation, may take a trajectory across the boundary into a "forbidden region." The naive way of dealing with this problem, which we refer to as the "standard" approach, is simply to reset the trajectory to the boundary, based on the argument that crossing the boundary actually signifies achieving the boundary. In this work we show, within the framework of the Euler method, that such resetting introduces a spurious force into the original diffusion process. This force may have a significant influence on trajectories that come close to a boundary. We propose a corrected numerical scheme, for simulating one-dimensional diffusion processes with naturally occurring boundaries. This involves correcting the standard approach, so that an exact property of the diffusion process is precisely respected. As a consequence, the proposed scheme does not introduce a spurious force into the dynamics. We present numerical test cases, based on exactly soluble one-dimensional problems with one or two boundaries, which suggest that, for a given value of the discrete time step, the proposed scheme leads to substantially more accurate results than the standard approach. Alternatively, the standard approach needs considerably more computation time to obtain a comparable level of accuracy to the proposed scheme, because the standard approach requires a significantly smaller time step.

  14. The encounter and analysis of naturally occurring radionuclides in gas and oil production and processing

    International Nuclear Information System (INIS)

    Hartog, F.A.; Jonkers, G.; Knaepen, W.A.I.

    1996-01-01

    As a result of oil and gas production, radioactive daughter elements from the uranium and thorium decay series can be mobilized and transported away from the reservoir. Due to changes in flow regime, temperature, pressure or chemical environment NORs (Naturally Occurring Radionuclides) may build up in products, by-products or waste streams from gas and oil production and processing facilities. Products containing NORs are commonly denoted by the acronym NORM (Naturally Occurring Radioactive Materials). Main topics of this paper are: E and P (Exploration and Production) NORM characteristics; incentives for NORM analysis; NORM analysis; interlaboratory test programme; analysis techniques; results and conclusions of the test programme. 4 figs., 2 tabs

  15. Inhibition and kinetic studies of cellulose- and hemicellulose-degrading enzymes of Ganoderma boninense by naturally occurring phenolic compounds.

    Science.gov (United States)

    Surendran, A; Siddiqui, Y; Ali, N S; Manickam, S

    2018-06-01

    Ganoderma sp, the causal pathogen of the basal stem rot (BSR) disease of oil palm, secretes extracellular hydrolytic enzymes. These play an important role in the pathogenesis of BSR by nourishing the pathogen through the digestion of cellulose and hemicellulose of the host tissue. Active suppression of hydrolytic enzymes secreted by Ganoderma boninense by various naturally occurring phenolic compounds and estimation of their efficacy on pathogen suppression is focused in this study. Ten naturally occurring phenolic compounds were assessed for their inhibitory effect on the hydrolytic enzymes of G. boninense. The enzyme kinetics (V max and K m ) and the stability of the hydrolytic enzymes were also characterized. The selected compounds had shown inhibitory effect at various concentrations. Two types of inhibitions namely uncompetitive and noncompetitive were observed in the presence of phenolic compounds. Among all the phenolic compounds tested, benzoic acid was the most effective compound suppressive to the growth and production of hydrolytic enzymes secreted by G. boninense. The phenolic compounds as inhibitory agents can be a better replacement for the metal ions which are known as conventional inhibitors till date. The three hydrolytic enzymes were stable in a wide range of pH and temperature. These findings highlight the efficacy of the applications of phenolic compounds to control Ganoderma. The study has proved a replacement for chemical controls of G. boninense with naturally occurring phenolic compounds. © 2018 The Society for Applied Microbiology.

  16. Picturing survival memories: enhanced memory after fitness-relevant processing occurs for verbal and visual stimuli.

    Science.gov (United States)

    Otgaar, Henry; Smeets, Tom; van Bergen, Saskia

    2010-01-01

    Recent studies have shown that processing words according to a survival scenario leads to superior retention relative to control conditions. Here, we examined whether a survival recall advantage could be elicited by using pictures. Furthermore, in Experiment 1, we were interested in whether survival processing also results in improved memory for details. Undergraduates rated the relevance of pictures in a survival, moving, or pleasantness scenario and were subsequently given a surprise free recall test. We found that survival processing yielded superior retention. We also found that distortions occurred more often in the survival condition than in the pleasantness condition. In Experiment 2, we directly compared the survival recall effect between pictures and words. A comparable survival recall advantage was found for pictures and words. The present findings support the idea that memory is enhanced by processing information in terms of fitness value, yet at the same time, the present results suggest that this may increase the risk for memory distortions.

  17. Engineered Barrier System Degradation, Flow, and Transport Process Model Report

    Energy Technology Data Exchange (ETDEWEB)

    E.L. Hardin

    2000-07-17

    The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II).

  18. Engineered Barrier System Degradation, Flow, and Transport Process Model Report

    International Nuclear Information System (INIS)

    E.L. Hardin

    2000-01-01

    The Engineered Barrier System Degradation, Flow, and Transport Process Model Report (EBS PMR) is one of nine PMRs supporting the Total System Performance Assessment (TSPA) being developed by the Yucca Mountain Project for the Site Recommendation Report (SRR). The EBS PMR summarizes the development and abstraction of models for processes that govern the evolution of conditions within the emplacement drifts of a potential high-level nuclear waste repository at Yucca Mountain, Nye County, Nevada. Details of these individual models are documented in 23 supporting Analysis/Model Reports (AMRs). Nineteen of these AMRs are for process models, and the remaining 4 describe the abstraction of results for application in TSPA. The process models themselves cluster around four major topics: ''Water Distribution and Removal Model, Physical and Chemical Environment Model, Radionuclide Transport Model, and Multiscale Thermohydrologic Model''. One AMR (Engineered Barrier System-Features, Events, and Processes/Degradation Modes Analysis) summarizes the formal screening analysis used to select the Features, Events, and Processes (FEPs) included in TSPA and those excluded from further consideration. Performance of a potential Yucca Mountain high-level radioactive waste repository depends on both the natural barrier system (NBS) and the engineered barrier system (EBS) and on their interactions. Although the waste packages are generally considered as components of the EBS, the EBS as defined in the EBS PMR includes all engineered components outside the waste packages. The principal function of the EBS is to complement the geologic system in limiting the amount of water contacting nuclear waste. A number of alternatives were considered by the Project for different EBS designs that could provide better performance than the design analyzed for the Viability Assessment. The design concept selected was Enhanced Design Alternative II (EDA II)

  19. Influence of the dose rate in the PVDF degradation processes

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Adriana S.M.; Pereira, Claubia, E-mail: adriananuclear@yahoo.com.br, E-mail: claubia@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Gual, Maritza R., E-mail: maritzargual@gmail.com [Instituto Superior de Tecnologias y Ciencias Aplicadas (InsTEC), Departamento de Ingenieria Nuclear, La Habana (Cuba); Faria, Luiz O., E-mail: farialo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    Modification in polymeric structure of plastic material can be brought either by conventional chemical means or by exposure to ionization radiation from gamma radioactive sources or highly accelerated electrons. The prominent drawbacks of chemical cross-linking typically involve the generation by products such as peroxide degradation. Radiation cross-linking technologies include: application in cable and wire, application in rubber tyres, radiation vulcanization of rubber latex, polymer recycling, hydrogels etc. The degradation of PVDF polymer exposed to gamma irradiation in oxygen atmosphere in high dose rate has been studied and compared to obtained under smaller dose rates. The samples were irradiated with a Co-60 source at constant dose rate (12 kGy/h and 2,592 kGy/h), with doses ranging from 100 kGy to 3,000 kGy. Different dose rate determine the prevalence of the processes being evaluated in this work by thermal measurements and infrared spectroscopy. It is shown that the degradation processes involve chain scissions and crosslink formation. The formation of oxidation products was shown at the surface of the irradiated film. The FTIR data revealed absorption bands at 1730 and 1853 cm{sup -1} which were attributed to the stretch of C=O bonds, at 1715 and 1754 cm{sup -1} which were attributed to the C=C stretching and at 3518, 3585 and 3673 cm{sup -1} which were associated with NH stretch of NH{sub 2} and OH. Thermogravimetric studies reveal that the irradiation induced the increasing residues and decrease of the temperature of the decomposition start. (author)

  20. Influence of the dose rate in the PVDF degradation processes

    International Nuclear Information System (INIS)

    Batista, Adriana S.M.; Pereira, Claubia; Gual, Maritza R.; Faria, Luiz O.

    2015-01-01

    Modification in polymeric structure of plastic material can be brought either by conventional chemical means or by exposure to ionization radiation from gamma radioactive sources or highly accelerated electrons. The prominent drawbacks of chemical cross-linking typically involve the generation by products such as peroxide degradation. Radiation cross-linking technologies include: application in cable and wire, application in rubber tyres, radiation vulcanization of rubber latex, polymer recycling, hydrogels etc. The degradation of PVDF polymer exposed to gamma irradiation in oxygen atmosphere in high dose rate has been studied and compared to obtained under smaller dose rates. The samples were irradiated with a Co-60 source at constant dose rate (12 kGy/h and 2,592 kGy/h), with doses ranging from 100 kGy to 3,000 kGy. Different dose rate determine the prevalence of the processes being evaluated in this work by thermal measurements and infrared spectroscopy. It is shown that the degradation processes involve chain scissions and crosslink formation. The formation of oxidation products was shown at the surface of the irradiated film. The FTIR data revealed absorption bands at 1730 and 1853 cm -1 which were attributed to the stretch of C=O bonds, at 1715 and 1754 cm -1 which were attributed to the C=C stretching and at 3518, 3585 and 3673 cm -1 which were associated with NH stretch of NH 2 and OH. Thermogravimetric studies reveal that the irradiation induced the increasing residues and decrease of the temperature of the decomposition start. (author)

  1. Degradation of ethylenethiourea pesticide metabolite from water by photocatalytic processes.

    Science.gov (United States)

    Bottrel, Sue Ellen C; Amorim, Camila C; Leão, Mônica M D; Costa, Elizângela P; Lacerda, Igor A

    2014-01-01

    In this study, photocatalytic (photo-Fenton and H2O2/UV) and dark Fenton processes were used to remove ethylenethiourea (ETU) from water. The experiments were conducted in a photo-reactor with an 80 W mercury vapor lamp. The mineralization of ETU was determined by total organic carbon analysis, and ETU degradation was qualitatively monitored by the reduction of UV absorbance at 232 nm. A higher mineralization efficiency was obtained by using the photo-peroxidation process (UV/H2O2). Approximately 77% of ETU was mineralized within 120 min of the reaction using [H2O2]0 = 400 mg L(-1). The photo-Fenton process mineralized 70% of the ETU with [H2O2]0 = 800 mg L(-1) and [Fe(2+)] = 400 mg L(-1), and there is evidence that hydrogen peroxide was the limiting reagent in the reaction because it was rapidly consumed. Moreover, increasing the concentration of H2O2 from 800 mg L(-1) to 1200 mg L(-1) did not enhance the degradation of ETU. Kinetics studies revealed that the pseudo-second-order model best fit the experimental conditions. The k values for the UV/H2O2 and photo-Fenton processes were determined to be 6.2 × 10(-4) mg L(-1) min(-1) and 7.7 × 10(-4) mg L(-1) min(-1), respectively. The mineralization of ETU in the absence of hydrogen peroxide has led to the conclusion that ETU transformation products are susceptible to photolysis by UV light. These are promising results for further research. The processes that were investigated can be used to remove pesticide metabolites from drinking water sources and wastewater in developing countries.

  2. Degradation of morphine in opium poppy processing waste composting.

    Science.gov (United States)

    Wang, Yin Quan; Zhang, Jin Lin; Schuchardt, Frank; Wang, Yan

    2014-09-01

    To investigate morphine degradation and optimize turning frequency in opium poppy processing waste composting, a pilot scale windrow composting trial was run for 55 days. Four treatments were designed as without turning (A1), every 5 days turning (A2), every 10 days turning (A3) and every 15 days turning (A4). During composting, a range of physicochemical parameters including the residual morphine degradation, temperature, pH, and the contents of total C, total N, total P and total K were investigated. For all treatments, the residual morphine content decreased below the detection limit and reached the safety standards after day 30 of composting, the longest duration of high temperature (⩾50 °C) was observed in A3, pH increased 16.9-17.54%, total carbon content decreased 15.5-22.5%, C/N ratio reduced from 46 to 26, and the content of total phosphorus and total potassium increased slightly. The final compost obtained by a mixture of all four piles was up to 55.3% of organic matter, 3.3% of total nutrient (N, P2O5 and K2O) and 7.6 of pH. A turning frequency of every ten days for a windrow composting of opium poppy processing waste is recommended to produce homogenous compost. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Atrazine degradation using chemical-free process of USUV: Analysis of the micro-heterogeneous environments and the degradation mechanisms

    International Nuclear Information System (INIS)

    Xu, L.J.; Chu, W.; Graham, Nigel

    2014-01-01

    Graphical abstract: - Highlights: • Two chemical-free AOP processes are combined to enhance atrazine degradation. • ATZ degradation in sonophotolytic process was analyzed using a previous proposed model. • The micro-bubble/liquid heterogeneous environments in sonolytic processes were investigated. • The salt effects on different sonolytic processes were examined. • ATZ degradation mechanisms were investigated and pathways were proposed. - Abstract: The effectiveness of sonolysis (US), photolysis (UV), and sonophotolysis (USUV) for the degradation of atrazine (ATZ) was investigated. An untypical kinetics analysis was found useful to describe the combined process, which is compatible to pseudo first-order kinetics. The heterogeneous environments of two different ultrasounds (20 and 400 kHz) were evaluated. The heterogeneous distribution of ATZ in the ultrasonic solution was found critical in determining the reaction rates at different frequencies. The presence of NaCl would promote/inhibit the rates by the growth and decline of “salting out” effect and surface tension. The benefits of combining these two processes were for the first time investigated from the aspect of promoting the intermediates degradation which were resistant in individual processes. UV caused a rapid transformation of ATZ to 2-hydroxyatrazine (OIET), which was insensitive to UV irradiation; however, US and USUV were able to degrade OIET and other intermediates through • OH attack. On the other hand, UV irradiation also could promote radical generation via H 2 O 2 decomposition, thereby resulting in less accumulation of more hydrophilic intermediates, which are difficult to degradation in the US process. Reaction pathways for ATZ degradation by all three processes are proposed. USUV achieved the greatest degree of ATZ mineralization with more than 60% TOC removed, contributed solely by the oxidation of side chains. Ammeline was found to be the only end-product in both US and USUV

  4. Atrazine degradation using chemical-free process of USUV: Analysis of the micro-heterogeneous environments and the degradation mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Xu, L.J., E-mail: xulijie827@gmail.com [Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Chu, W., E-mail: cewchu@polyu.edu.hk [Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Graham, Nigel, E-mail: n.graham@imperial.ac.uk [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)

    2014-06-30

    Graphical abstract: - Highlights: • Two chemical-free AOP processes are combined to enhance atrazine degradation. • ATZ degradation in sonophotolytic process was analyzed using a previous proposed model. • The micro-bubble/liquid heterogeneous environments in sonolytic processes were investigated. • The salt effects on different sonolytic processes were examined. • ATZ degradation mechanisms were investigated and pathways were proposed. - Abstract: The effectiveness of sonolysis (US), photolysis (UV), and sonophotolysis (USUV) for the degradation of atrazine (ATZ) was investigated. An untypical kinetics analysis was found useful to describe the combined process, which is compatible to pseudo first-order kinetics. The heterogeneous environments of two different ultrasounds (20 and 400 kHz) were evaluated. The heterogeneous distribution of ATZ in the ultrasonic solution was found critical in determining the reaction rates at different frequencies. The presence of NaCl would promote/inhibit the rates by the growth and decline of “salting out” effect and surface tension. The benefits of combining these two processes were for the first time investigated from the aspect of promoting the intermediates degradation which were resistant in individual processes. UV caused a rapid transformation of ATZ to 2-hydroxyatrazine (OIET), which was insensitive to UV irradiation; however, US and USUV were able to degrade OIET and other intermediates through • OH attack. On the other hand, UV irradiation also could promote radical generation via H{sub 2}O{sub 2} decomposition, thereby resulting in less accumulation of more hydrophilic intermediates, which are difficult to degradation in the US process. Reaction pathways for ATZ degradation by all three processes are proposed. USUV achieved the greatest degree of ATZ mineralization with more than 60% TOC removed, contributed solely by the oxidation of side chains. Ammeline was found to be the only end-product in both US

  5. Degradation Processes of Al-Zn Welded Joints

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2014-01-01

    Full Text Available Welding of metal materials belongs to non-demountable joints. Current trend especially in an automotive industry is to join materials with a different melting temperature. Most of all, there are dural profiles with ferrite or austenite steel. The reason for this is the effort to lower the weight of the whole construction and at the same time preserve sufficient mechanical characteristics. However, there is a big risk of different electrical potentials of both of these metals in this type of non-demountable joints. The experimental part of this paper brings evaluation of mechanical-corrosion processes of overlapped joints produced by the CMT (cold metal transfer method. The base material for weld bead is dural sheet AlMg3 and dural sheet with a surface treatment aluzinc DX51D+AZ 150. Material AlSi5 in the form of a wire was used as an additional material for a welding bath. Method CMT was used in order to create a weld bead. Initial analysis of weld bead was done visually using a binocular microscope. Further, a metallographic analysis of weld bead and base material was processed. The aim was to identify the heat affected area around the welded joint. Microhardness of intermetallic aluminium phases was measured, after the identification of intermetallic phases a chemical analysis EDS was processed. Prepared samples underwent corrosion degradation in a salt spray environment in compliance with the norm ČSN EN ISO 9227. Visual and metallographic evaluation of the individual samples was processed after every week of exposition to the salt spray environment. The goal of this experiment was to record the initial impulse of galvanic corrosion which consists in corrosion degradation in the area of welded joint.

  6. Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process.

    Science.gov (United States)

    Vieira, Gabriela A L; Magrini, Mariana Juventina; Bonugli-Santos, Rafaella C; Rodrigues, Marili V N; Sette, Lara D

    2018-05-03

    Pyrene and benzo[a]pyrene (BaP) are high molecular weight polycyclic aromatic hydrocarbons (PAHs) recalcitrant to microbial attack. Although studies related to the microbial degradation of PAHs have been carried out in the last decades, little is known about degradation of these environmental pollutants by fungi from marine origin. Therefore, this study aimed to select one PAHs degrader among three marine-derived basidiomycete fungi and to study its pyrene detoxification/degradation. Marasmiellus sp. CBMAI 1062 showed higher levels of pyrene and BaP degradation and was subjected to studies related to pyrene degradation optimization using experimental design, acute toxicity, organic carbon removal (TOC), and metabolite evaluation. The experimental design resulted in an efficient pyrene degradation, reducing the experiment time while the PAH concentration applied in the assays was increased. The selected fungus was able to degrade almost 100% of pyrene (0.08mgmL -1 ) after 48h of incubation under saline condition, without generating toxic compounds and with a TOC reduction of 17%. Intermediate metabolites of pyrene degradation were identified, suggesting that the fungus degraded the compound via the cytochrome P450 system and epoxide hydrolases. These results highlight the relevance of marine-derived fungi in the field of PAH bioremediation, adding value to the blue biotechnology. Copyright © 2018. Published by Elsevier Editora Ltda.

  7. Evaluation of the mercaptobenzothiazole degradation by combined adsorption process and Fenton reaction using iron mining residue.

    Science.gov (United States)

    Martins, Adriana Lau da Silva; Teixeira, Luís Alberto César; da Fonseca, Fabiana Valéria; Yokoyama, Lídia

    2017-08-01

    The present study investigated the degradation of mercaptobenzothiazole (MBT), evaluating homogeneous and heterogeneous systems. An iron mineral residue from the desliming step of iron mining was used as a source in the Fenton-like reaction (advanced oxidation process). A granulometric analysis of the residue was performed and yielded fractions with high hematite (Fe 2 O 3 ) and low quartz content in sieves from 74 to below 44 mm. In this particle size range, the hematite content from 58.9% to 67.4% and the Brunauer-Emmett-Teller area from 0.1345 to 1.3137 m 2  g -1 were obtained. The zeta potential curves as a function of pH were obtained for the residue, the MBT solution and mixtures thereof. The adsorption of MBT in the residue and its degradation through the Fenton-like reaction were investigated. Adsorption tests and the Fenton-like reaction were carried out, where the MBT species and the residue are oppositely charged, yielding, respectively, 10% MBT adsorption on the surface of the residue and 100% MBT degradation by the Fenton-like reaction at pH 3, hydrogen peroxide concentration of 25 mg L -1 , residue concentration of 3 g L -1 , 200 rpm and 25°C, from a 100 mg L -1 MBT solution. MBT degradation was found to occur mainly by the heterogeneous Fenton-like process.

  8. Degradation Processes of Pesticides Used in Potato Cultivations.

    Science.gov (United States)

    Kurek, M; Barchańska, H; Turek, M

    Potato is one of the most important crops, after maize, rice and wheat. Its global production is about 300 million tons per year and is constantly increasing. It grows in temperate climate and is used as a source of starch, food, and in breeding industry.Potato cultivation requires application of numerous agro-technical products, including pesticides, since it can be affected by insects, weeds, fungi, and viruses. In the European Union the most frequently used pesticides in potato cultivations check are: thiamethoxam, lambda-cyhalothrin and deltamethrin (insecticides), rimsulfuron (herbicide) and metalaxyl (fungicide).Application of pesticides improves crop efficiency, however, as pesticides are not totally selective, it affects also non-target organisms. Moreover, the agrochemicals may accumulate in crops and, as a consequence, negatively influence the quality of food products and consumer health. Additional risks of plant protection products are related to their derivatives, that are created both in the environment (soil, water) and in plant organisms, since many of these compounds may exhibit toxic effects.This article is devoted to the degradation processes of pesticides used in potato crop protection. Attention is also paid to the toxicity of both parent compounds and their degradation products for living organisms, including humans. Information about the level of pesticide contamination in the environment (water, soil) and accumulation level in edible plants complement the current knowledge about the risks associated with widespread use of thiamethoxam, lambda-cyhalothrin and deltamethrin, rimsulfuron and metalaxyl in potato cultivation.

  9. Preferential processing of self-relevant stimuli occurs mainly at the perceptual and conscious stages of information processing.

    Science.gov (United States)

    Tacikowski, P; Ehrsson, H H

    2016-04-01

    Self-related stimuli, such as one's own name or face, are processed faster and more accurately than other types of stimuli. However, what remains unknown is at which stage of the information processing hierarchy this preferential processing occurs. Our first aim was to determine whether preferential self-processing involves mainly perceptual stages or also post-perceptual stages. We found that self-related priming was stronger than other-related priming only because of perceptual prime-target congruency. Our second aim was to dissociate the role of conscious and unconscious factors in preferential self-processing. To this end, we compared the "self" and "other" conditions in trials where primes were masked or unmasked. In two separate experiments, we found that self-related priming was stronger than other-related priming but only in the unmasked trials. Together, our results suggest that preferential access to the self-concept occurs mainly at the perceptual and conscious stages of the stimulus processing hierarchy. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Study of Aramid Fiber/Polychloroprene Recycling Process by Thermal Degradation

    Directory of Open Access Journals (Sweden)

    Igor Dabkiewicz

    2016-07-01

    Full Text Available Aramid fiber is an important polymer applied as reinforcement in high-performance composites, which, due its exceptional properties, becomes an excellent impact absorption material. It has been broadly utilized in aeronautic industry and ballistic protection. In aircrafts, it is mainly used in secondary structures, such as fairings, floor panels, and bullet proof structures in helicopters, whereas, in ballistic protection industry, it is applied in automotive armor and bullet proof vest. Under environmental perspective, it is worrying the development and application of composites, which generate proportional discards of these materials, whether originated from manufacturing process, spare parts or end of life cycle. High-performance composite materials like those using aramid fiber are generally difficult to recycle due to their properties and the difficulty for the separation of the components, making their recycling economically unviable. From the characteristics of composite materials and environmental viewpoint, this paper presents a new aramid fiber recycling process. The main objective of this research was to study different recycling methods in aramid fibers/Neoprene® composites. To promote the Neoprene® degradation, it was used a pyrolysis oven with controlled atmosphere and CO 2 injection. For the degraded separation, it was designed a mechanical washing machine in which the most degraded separation occurred. To complete the materials separation, it was employed a manual cleaning process, and, at least to prove the efficacy of the process, it was applied a tensile test in the yarns.

  11. State of the art review of degradation processes in LMFBR materials. Volume II. Corrosion behavior

    International Nuclear Information System (INIS)

    Dillon, R.D.

    1975-01-01

    Degradation of materials exposed to Na in LMFBR service is reviewed. The degradation processes are discussed in sections on corrosion and mass transfer, erosion, wear and self welding, sodium--water reactions, and external corrosion. (JRD)

  12. Modelling of processes occurring in deep geological repository - development of new modules in the GoldSim environment

    International Nuclear Information System (INIS)

    Vopalka, D.; Lukin, D.; Vokal, A.

    2006-01-01

    Three new modules modelling the processes that occur in a deep geological repository have been prepared in the GoldSim computer code environment (using its Transport Module). These modules help to understand the role of selected parameters in the near-field region of the final repository and to prepare an own complex model of the repository behaviour. The source term module includes radioactive decay and ingrowth in the canister, first order degradation of fuel matrix, solubility limitation of the concentration of the studied nuclides, and diffusive migration through the surrounding bentonite layer controlled by the output boundary condition formulated with respect to the rate of water flow in the rock. The corrosion module describes corrosion of canisters made of carbon steel and transport of corrosion products in the near-field region. This module computes balance equations between dissolving species and species transported by diffusion and/or advection from the surface of a solid material. The diffusion module that includes also non-linear form of the interaction isotherm can be used for an evaluation of small-scale diffusion experiments. (author)

  13. Modelling of processes occurring in deep geological repository - Development of new modules in the GoldSim environment

    Science.gov (United States)

    Vopálka, D.; Lukin, D.; Vokál, A.

    2006-01-01

    Three new modules modelling the processes that occur in a deep geological repository have been prepared in the GoldSim computer code environment (using its Transport Module). These modules help to understand the role of selected parameters in the near-field region of the final repository and to prepare an own complex model of the repository behaviour. The source term module includes radioactive decay and ingrowth in the canister, first order degradation of fuel matrix, solubility limitation of the concentration of the studied nuclides, and diffusive migration through the surrounding bentonite layer controlled by the output boundary condition formulated with respect to the rate of water flow in the rock. The corrosion module describes corrosion of canisters made of carbon steel and transport of corrosion products in the near-field region. This module computes balance equations between dissolving species and species transported by diffusion and/or advection from the surface of a solid material. The diffusion module that includes also non-linear form of the interaction isotherm can be used for an evaluation of small-scale diffusion experiments.

  14. Industries processing naturally occurring radioactive materials: twenty years of emission data in the Netherlands

    International Nuclear Information System (INIS)

    Tanzi, C.P.

    2008-01-01

    This paper provides a review of the dose assessment of discharges to air of two industries processing NORM (Naturally Occurring Radioactive Materials) in the Netherlands. An industrial plant producing elemental phosphorus (thermal process, unique within Europe) reports since 1987 its emission data to the Dutch Ministry of the Environment (VROM: Ministry of Housing, Spatial Planning and the Environment). This plant accounts for the highest release of Po-210 to air in the Netherlands, with a yearly average of approximately 500 GBq. Other significant NORM discharges to air arise from an industrial plant with blast-furnaces for steel production. Yearly discharges fall under permit, and are reported, since 1993. RIVM, the National Institute for Public Health and the Environment, is tasked by the Ministry to assess the dose to the general public arising from these discharges to air. Air transport modelling is used to determine both air concentration (for inhalation exposure) and deposition rate of the radionuclides. A (conservative) committed ingestion dose is determined by modelling the uptake of radionuclides from contaminated farmland, and assuming a food basket to be fairly representative for the population of the Netherlands. Discharges to water in the Netherlands have decreased in the past twenty years, due both to the closure of two phosphoric acid plants a decade ago and the improved treatment of waste fluids by other NORM industries. The collective dose assessed from discharges to air since 1987 is presented here. (author)

  15. Activity of 3-Ketosteroid 9α-Hydroxylase (KshAB) Indicates Cholesterol Side Chain and Ring Degradation Occur Simultaneously in Mycobacterium tuberculosis*

    Science.gov (United States)

    Capyk, Jenna K.; Casabon, Israël; Gruninger, Robert; Strynadka, Natalie C.; Eltis, Lindsay D.

    2011-01-01

    Mycobacterium tuberculosis (Mtb), a significant global pathogen, contains a cholesterol catabolic pathway. Although the precise role of cholesterol catabolism in Mtb remains unclear, the Rieske monooxygenase in this pathway, 3-ketosteroid 9α-hydroxylase (KshAB), has been identified as a virulence factor. To investigate the physiological substrate of KshAB, a rhodococcal acyl-CoA synthetase was used to produce the coenzyme A thioesters of two cholesterol derivatives: 3-oxo-23,24-bisnorchol-4-en-22-oic acid (forming 4-BNC-CoA) and 3-oxo-23,24-bisnorchola-1,4-dien-22-oic acid (forming 1,4-BNC-CoA). The apparent specificity constant (kcat/Km) of KshAB for the CoA thioester substrates was 20–30 times that for the corresponding 17-keto compounds previously proposed as physiological substrates. The apparent KmO2 was 90 ± 10 μm in the presence of 1,4-BNC-CoA, consistent with the value for two other cholesterol catabolic oxygenases. The Δ1 ketosteroid dehydrogenase KstD acted with KshAB to cleave steroid ring B with a specific activity eight times greater for a CoA thioester than the corresponding ketone. Finally, modeling 1,4-BNC-CoA into the KshA crystal structure suggested that the CoA moiety binds in a pocket at the mouth of the active site channel and could contribute to substrate specificity. These results indicate that the physiological substrates of KshAB are CoA thioester intermediates of cholesterol side chain degradation and that side chain and ring degradation occur concurrently in Mtb. This finding has implications for steroid metabolites potentially released by the pathogen during infection and for the design of inhibitors for cholesterol-degrading enzymes. The methodologies and rhodococcal enzymes used to generate thioesters will facilitate the further study of cholesterol catabolism. PMID:21987574

  16. High Temperature Degradation of Powder-processed Ni-based Superalloy

    Directory of Open Access Journals (Sweden)

    Natália Luptáková

    2015-05-01

    Full Text Available The aim of present work is to study the high temperature degradation of the powder-processed polycrystalline superalloy Ni-15Cr-18Co-4Al-3.5Ti-5Mo. This superalloy has been applied as material for grips of a creep machine. The material was exposed at 1100 °C for about 10 days at 10 MPa stress. During the creep test occurred unacceptable creep deformation of grips as well as severe surface oxidation with scales peeling off. Three types of the microstructure were observed in the studied alloy: (i unexposed state; (ii heat treated (annealing - 10 min/1200 °C and (iii after using as a part of the equipment of the creep machine during the creep test. It is shown that the microstructure degradation resulting from the revealed γ´ phase fcc Ni3(Al,Ti particles preferentially created at the grain boundaries of the samples after performing creep tests affects mechanical properties of the alloy and represents a significant contribution to all degradation processes affecting performance and service life of the creep machine grips. Based on investigation and obtained results, the given material is not recommended to be used for grips of creep machine at temperatures above 1000 °C.

  17. The rheology, degradation, processing, and characterization of renewable resource polymers

    Science.gov (United States)

    Conrad, Jason David

    Renewable resource polymers have become an increasingly popular alternative to conventional fossil fuel based polymers over the past couple decades. The push by the government as well as both industrial and consumer markets to go "green" has provided the drive for companies to research and develop new materials that are more environmentally friendly and which are derived from renewable materials. Two polymers that are currently being produced commercially are poly-lactic acid (PLA) and polyhydroxyalkanoate (PHA) copolymers, both of which can be derived from renewable feedstocks and have shown to exhibit similar properties to conventional materials such as polypropylene, polyethylene, polystyrene, and PET. PLA and PHA are being used in many applications including food packaging, disposable cups, grocery bags, and biomedical applications. In this work, we report on the rheological properties of blends of PLA and PHA copolymers. The specific materials used in the study include Natureworks RTM 7000D grade PLA and PHA copolymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Blends ranging from 10 to 50 percent PHA by weight are also examined. Shear and extensional experiments are performed to characterize the flow behavior of the materials in different flow fields. Transient experiments are performed to study the shear rheology over time in order to determine how the viscoelastic properties change under typical processing conditions and understand the thermal degradation behavior of the materials. For the blends, it is determined that increasing the PHA concentration in the blend results in a decrease in viscosity and increase in degradation. Models are fit to the viscosity of the blends using the pure material viscosities in order to be able to predict the behavior at a given blend composition. We also investigate the processability of these materials into films and examine the resultant properties of the cast films. The mechanical and thermal properties of the

  18. Degradation of phenolic compounds by using advanced oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, M. [Univ. de los Andes, Escuela Basica de Ingenieria, La Hechicera, Merida (Venezuela); Hincapie, M. [Dept. de Ingenieria Sanitaria y Ambiental, Univ. de Antioquia, Medellin (Colombia); Curco, D.; Contreras, S.; Gimenez, J.; Esplugas, S. [Dept. de Ingenieria Quimica, Facultad de Quimica, Univ. de Barcelona, Barcelona (Spain)

    2003-07-01

    A new empirical kinetic equation [r = k{sub 1}c - k{sub 2} (c{sub 0} - c)] is proposed for the photocatalytic degradation of phenolic compounds. This equation considers the influence of the intermediates in the degradation of the pollutant. The correct formulation of the contaminant mass balance in the experimental device that operates in recycle mode was done. The proposed empirical kinetic equation fitted quite well with the experimental results obtained in the TiO{sub 2}-photocatalytic degradation of phenol. (orig.)

  19. Background Noise Degrades Central Auditory Processing in Toddlers.

    Science.gov (United States)

    Niemitalo-Haapola, Elina; Haapala, Sini; Jansson-Verkasalo, Eira; Kujala, Teija

    2015-01-01

    Noise, as an unwanted sound, has become one of modern society's environmental conundrums, and many children are exposed to higher noise levels than previously assumed. However, the effects of background noise on central auditory processing of toddlers, who are still acquiring language skills, have so far not been determined. The authors evaluated the effects of background noise on toddlers' speech-sound processing by recording event-related brain potentials. The hypothesis was that background noise modulates neural speech-sound encoding and degrades speech-sound discrimination. Obligatory P1 and N2 responses for standard syllables and the mismatch negativity (MMN) response for five different syllable deviants presented in a linguistic multifeature paradigm were recorded in silent and background noise conditions. The participants were 18 typically developing 22- to 26-month-old monolingual children with healthy ears. The results showed that the P1 amplitude was smaller and the N2 amplitude larger in the noisy conditions compared with the silent conditions. In the noisy condition, the MMN was absent for the intensity and vowel changes and diminished for the consonant, frequency, and vowel duration changes embedded in speech syllables. Furthermore, the frontal MMN component was attenuated in the noisy condition. However, noise had no effect on P1, N2, or MMN latencies. The results from this study suggest multiple effects of background noise on the central auditory processing of toddlers. It modulates the early stages of sound encoding and dampens neural discrimination vital for accurate speech perception. These results imply that speech processing of toddlers, who may spend long periods of daytime in noisy conditions, is vulnerable to background noise. In noisy conditions, toddlers' neural representations of some speech sounds might be weakened. Thus, special attention should be paid to acoustic conditions and background noise levels in children's daily environments

  20. Age Differences in Face Processing: The Role of Perceptual Degradation and Holistic Processing.

    Science.gov (United States)

    Boutet, Isabelle; Meinhardt-Injac, Bozana

    2018-01-24

    We simultaneously investigated the role of three hypotheses regarding age-related differences in face processing: perceptual degradation, impaired holistic processing, and an interaction between the two. Young adults (YA) aged 20-33-year olds, middle-age adults (MA) aged 50-64-year olds, and older adults (OA) aged 65-82-year olds were tested on the context congruency paradigm, which allows measurement of face-specific holistic processing across the life span (Meinhardt-Injac, Persike & Meinhardt, 2014. Acta Psychologica, 151, 155-163). Perceptual degradation was examined by measuring performance with faces that were not filtered (FSF), with faces filtered to preserve low spatial frequencies (LSF), and with faces filtered to preserve high spatial frequencies (HSF). We found that reducing perceptual signal strength had a greater impact on MA and OA for HSF faces, but not LSF faces. Context congruency effects were significant and of comparable magnitude across ages for FSF, LSF, and HSF faces. By using watches as control objects, we show that these holistic effects reflect face-specific mechanisms in all age groups. Our results support the perceptual degradation hypothesis for faces containing only HSF and suggest that holistic processing is preserved in aging even under conditions of reduced signal strength. © The Author(s) 2018. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Study of the degradation process of polyimide induced by high energetic ion irradiation

    International Nuclear Information System (INIS)

    Severin, Daniel

    2008-01-01

    The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10 10 -5 x 10 12 ions/cm 2 ). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10 10 ions/cm 2 ). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO 2 , and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a critical material degradation which

  2. Study of the degradation process of polyimide induced by high energetic ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Severin, Daniel

    2008-09-19

    The dissertation focuses on the radiation hardness of Kapton under extreme radiation environment conditions. To study ion-beam induced modifications, Kapton foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (e.g. Ti, Mo, Au, and U) within a large fluence regime (1 x 10{sup 10}-5 x 10{sup 12} ions/cm{sup 2}). The irradiated Kapton foils were analysed by means of infrared and UV/Vis spectroscopy, tensile strength measurement, mass loss analysis, and dielectric relaxation spectroscopy. For testing the radiation stability of Kapton at the cryogenic operation temperature (5-10 K) of the superconducting magnets, additional irradiation experiments were performed at the Grand Accelerateur National d' Ions Lourds (GANIL, France) focusing on the online analysis of the outgassing process of small volatile degradation fragments. The investigations of the electrical properties analysed by dielectric relaxation spectroscopy exhibit a different trend: high fluence irradiations with light ions (e.g. Ti) lead to a slight increase of the conductivity, whereas heavy ions (e.g. Sm, Au) cause a drastic change already in the fluence regime of nonoverlapping tracks (5 x 10{sup 10} ions/cm{sup 2}). Online analysis of the outgassing process during irradiation at cryogenic temperatures shows the release of a variety of small gaseous molecules (e.g. CO, CO{sub 2}, and short hydro carbons). Also a small amount of large polymer fragments is identified. The results allow the following conclusions which are of special interest for the application of Kapton as insulating material in a high-energetic particle radiation environment. a) The material degradation measured with the optical spectroscopy and tensile strength tests are scalable with the dose deposited by the ions. The high correlation of the results allows the prediction of the mechanical degradation with the simple and non-destructive infrared spectroscopy. The degradation curve points to a

  3. Activity of 3-ketosteroid 9α-hydroxylase (KshAB) indicates cholesterol side chain and ring degradation occur simultaneously in Mycobacterium tuberculosis.

    Science.gov (United States)

    Capyk, Jenna K; Casabon, Israël; Gruninger, Robert; Strynadka, Natalie C; Eltis, Lindsay D

    2011-11-25

    Mycobacterium tuberculosis (Mtb), a significant global pathogen, contains a cholesterol catabolic pathway. Although the precise role of cholesterol catabolism in Mtb remains unclear, the Rieske monooxygenase in this pathway, 3-ketosteroid 9α-hydroxylase (KshAB), has been identified as a virulence factor. To investigate the physiological substrate of KshAB, a rhodococcal acyl-CoA synthetase was used to produce the coenzyme A thioesters of two cholesterol derivatives: 3-oxo-23,24-bisnorchol-4-en-22-oic acid (forming 4-BNC-CoA) and 3-oxo-23,24-bisnorchola-1,4-dien-22-oic acid (forming 1,4-BNC-CoA). The apparent specificity constant (k(cat)/K(m)) of KshAB for the CoA thioester substrates was 20-30 times that for the corresponding 17-keto compounds previously proposed as physiological substrates. The apparent K(m)(O(2)) was 90 ± 10 μM in the presence of 1,4-BNC-CoA, consistent with the value for two other cholesterol catabolic oxygenases. The Δ(1) ketosteroid dehydrogenase KstD acted with KshAB to cleave steroid ring B with a specific activity eight times greater for a CoA thioester than the corresponding ketone. Finally, modeling 1,4-BNC-CoA into the KshA crystal structure suggested that the CoA moiety binds in a pocket at the mouth of the active site channel and could contribute to substrate specificity. These results indicate that the physiological substrates of KshAB are CoA thioester intermediates of cholesterol side chain degradation and that side chain and ring degradation occur concurrently in Mtb. This finding has implications for steroid metabolites potentially released by the pathogen during infection and for the design of inhibitors for cholesterol-degrading enzymes. The methodologies and rhodococcal enzymes used to generate thioesters will facilitate the further study of cholesterol catabolism.

  4. Thermal degradation process of poly (alpha-methylstyrene) microspheres coated with glow discharge polymer

    International Nuclear Information System (INIS)

    Zhang Zhanwen; Huang Yong; Tang Yongjian; Li Bo; Chen Sufen; He Zhibing

    2009-01-01

    Glow discharge polymer (GDP) shell was made by the decomposable mandrel technique using poly(alpha-methylstyrene) (PAMS) mandrel. The PAMS degradation rate and the GDP shell surface morphology at different equilibrium temperatures were investigated. Degradation rate was calculated from weight variation of PAMS before and after pyrolysis process. Experiment results indicate that the degradation rate decreases at the fixed equilibrium temperature and graded temperature can improve the rate. The degradation process has an effect on the GDP shell properties. The PAMS doesn't molten to flow liquid during degradation. But the degradation can reduce surface finish of GDP coatings. The GDP shell deffects are the result of the PAMS degradiation process. (authors)

  5. Landform Degradation and Slope Processes on Io: The Galileo View

    Science.gov (United States)

    Moore, Jeffrey M.; Sullivan, Robert J.; Chuang, Frank C.; Head, James W., III; McEwen, Alfred S.; Milazzo, Moses P.; Nixon, Brian E.; Pappalardo, Robert T.; Schenk, Paul M.; Turtle, Elizabeth P.; hide

    2001-01-01

    The Galileo mission has revealed remarkable evidence of mass movement and landform degradation on Io. We recognize four major slope types observed on a number of intermediate resolution (250 m/pixel) images and several additional textures on very high resolution (10 m/pixel) images. Slopes and scarps on Io often show evidence of erosion, seen in the simplest form as alcove-carving slumps and slides at all scales. Many of the mass movement deposits on Io are probably mostly the consequence of block release and brittle slope failure. Sputtering plays no significant role. Sapping as envisioned by McCauley et al. remains viable. We speculate that alcove-lined canyons seen in one observation and lobed deposits seen along the bases of scarps in several locations may reflect the plastic deformation and 'glacial' flow of interstitial volatiles (e.g., SO2) heated by locally high geothermal energy to mobilize the volatile. The appearance of some slopes and near-slope surface textures seen in very high resolution images is consistent with erosion from sublimation-degradation. However, a suitable volatile (e.g., H2S) that can sublimate fast enough to alter Io's youthful surface has not been identified. Disaggregation from chemical decomposition of solid S2O and other polysulfur oxides may conceivably operate on Io. This mechanism could degrade landforms in a manner that resembles degradation from sublimation, and at a rate that can compete with resurfacing.

  6. THE EFFECT OF DEGRADATION PROCESSES ON THE SERVICEABILITY OF BUILDING MATERIALS OF HISTORIC BUILDINGS

    Directory of Open Access Journals (Sweden)

    Jiří Witzany

    2016-10-01

    Full Text Available The article presents an analysis of degradation processes and partial results of an experimental research into materials and structures exposed to the effects of external environments with an emphasis on the effects of moisture and chemical degradation processes on major mechanical properties of sandstone.

  7. A Bayesian optimal design for degradation tests based on the inverse Gaussian process

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Weiwen; Liu, Yu; Li, Yan Feng; Zhu, Shun Peng; Huang, Hong Zhong [University of Electronic Science and Technology of China, Chengdu (China)

    2014-10-15

    The inverse Gaussian process is recently introduced as an attractive and flexible stochastic process for degradation modeling. This process has been demonstrated as a valuable complement for models that are developed on the basis of the Wiener and gamma processes. We investigate the optimal design of the degradation tests on the basis of the inverse Gaussian process. In addition to an optimal design with pre-estimated planning values of model parameters, we also address the issue of uncertainty in the planning values by using the Bayesian method. An average pre-posterior variance of reliability is used as the optimization criterion. A trade-off between sample size and number of degradation observations is investigated in the degradation test planning. The effects of priors on the optimal designs and on the value of prior information are also investigated and quantified. The degradation test planning of a GaAs Laser device is performed to demonstrate the proposed method.

  8. Application of UV-irradiated Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton systems to degrade model and natural occurring naphthenic acids.

    Science.gov (United States)

    Zhang, Ying; Chelme-Ayala, Pamela; Klamerth, Nikolaus; Gamal El-Din, Mohamed

    2017-07-01

    Naphthenic acids (NAs) are a highly complex mixture of organic compounds naturally present in bitumen and identified as the primary toxic constituent of oil sands process-affected water (OSPW). This work investigated the degradation of cyclohexanoic acid (CHA), a model NA compound, and natural occurring NAs during the UV photolysis of Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton processes. The results indicated that in the UV-Fe(III)NTA process at pH 8, the CHA removal increased with increasing NTA dose (0.18, 0.36 and 0.72 mM), while it was independent of the Fe(III) dose (0.09, 0.18 and 0.36 mM). Moreover, the three Fe concentrations had no influence on the photolysis of the Fe(III)NTA complex. The main responsible species for the CHA degradation was hydroxyl radical (OH), and the role of dissolved O 2 in the OH generation was found to be negligible. Real OSPW was treated with the UV-Fe(III)NTA and UV-NTA-Fenton advanced oxidation processes (AOPs). The removals of classical NAs (O 2 -NAs), oxidized NAs with one additional oxygen atom (O 3 -NAs) and with two additional oxygen atoms (O 4 -NAs) were 44.5%, 21.3%, and 25.2% in the UV-Fe(III)NTA process, respectively, and 98.4%, 86.0%, and 81.0% in the UV-NTA-Fenton process, respectively. There was no influence of O 2 on the NA removal in these two processes. The results also confirmed the high reactivity of the O 2 -NA species with more carbons and increasing number of rings or double bond equivalents. This work opens a new window for the possible treatment of OSPW at natural pH using these AOPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Finding the traces of behavioral and cognitive processes in big data and naturally occurring datasets.

    Science.gov (United States)

    Paxton, Alexandra; Griffiths, Thomas L

    2017-10-01

    Today, people generate and store more data than ever before as they interact with both real and virtual environments. These digital traces of behavior and cognition offer cognitive scientists and psychologists an unprecedented opportunity to test theories outside the laboratory. Despite general excitement about big data and naturally occurring datasets among researchers, three "gaps" stand in the way of their wider adoption in theory-driven research: the imagination gap, the skills gap, and the culture gap. We outline an approach to bridging these three gaps while respecting our responsibilities to the public as participants in and consumers of the resulting research. To that end, we introduce Data on the Mind ( http://www.dataonthemind.org ), a community-focused initiative aimed at meeting the unprecedented challenges and opportunities of theory-driven research with big data and naturally occurring datasets. We argue that big data and naturally occurring datasets are most powerfully used to supplement-not supplant-traditional experimental paradigms in order to understand human behavior and cognition, and we highlight emerging ethical issues related to the collection, sharing, and use of these powerful datasets.

  10. Degradation of di-2-ethylhexyl phthalate in aqueous solution by advanced oxidation process

    Directory of Open Access Journals (Sweden)

    Maryam Zarean

    2015-01-01

    Conclusion: It could be found that the UV/O3 process is a method for DEHP degradation in aqueous solution and may be recommended as a supplement with other processes for treatment of solutions containing low DEHP concentrations.

  11. Naturally occurring radioactive materials (NORM) in the oil and gas processing and production facilities

    International Nuclear Information System (INIS)

    Najera F, J.

    1994-01-01

    NORM contamination is produced by concentration in petroleum facilities of naturally occurring radioactive materials. The presence of NORM in petroleum reservoirs and in the oil and gas industry has been widely recognized. It's not a critical technical problem if you proceed timely to solve it. NORM is a great but controllable hazard to the human health and the environment, and represents a severe waste management problem. We suggest to the latino american oil companies to conduct studies to detect NORM contamination in their facilities an use to them to plan the appropriate actions to control the situation. (author). 15 refs

  12. How to measure a-few-nanometer-small LER occurring in EUV lithography processed feature

    Science.gov (United States)

    Kawada, Hiroki; Kawasaki, Takahiro; Kakuta, Junichi; Ikota, Masami; Kondo, Tsuyoshi

    2018-03-01

    For EUV lithography features we want to decrease the dose and/or energy of CD-SEM's probe beam because LER decreases with severe resist-material's shrink. Under such conditions, however, measured LER increases from true LER, due to LER bias that is fake LER caused by random noise in SEM image. A gap error occurs between the right and the left LERs. In this work we propose new procedures to obtain true LER by excluding the LER bias from the measured LER. To verify it we propose a LER's reference-metrology using TEM.

  13. Kinetic studies on the degradation of crystal violet by the Fenton oxidation process.

    Science.gov (United States)

    Wu, H; Fan, M M; Li, C F; Peng, M; Sheng, L J; Pan, Q; Song, G W

    2010-01-01

    The degradation of dye crystal violet (CV) by Fenton oxidation process was investigated. The UV-Vis spectrogram has shown that CV can be degraded effectively by Fenton oxidation process. Different system variables namely initial H(2)O(2) concentration, initial Fe(2 + ) concentration and reaction temperature, which have effect on the degradation of CV by Fenton oxidation process, have been studied systematically. The degradation kinetics of CV was also elucidated based on the experimental data. The degradation of CV obeys the first-order reaction kinetics. The kinetic model can be described as k=1.5 exp(-(7.5)/(RT))[H(2)O(2)](0)(0.8718)[Fe(2+)](0)(0.5062). According to the IR spectrogram, it is concluded that the benzene ring of crystal violet has been destroyed by Fenton oxidation. The result will be useful in treating dyeing wastewater containing CV by Fenton oxidation process.

  14. Effects of grain source, grain processing, and protein degradability on rumen kinetics and microbial protein synthesis in Boer kids.

    Science.gov (United States)

    Brassard, M-E; Chouinard, P Y; Berthiaume, R; Tremblay, G F; Gervais, R; Martineau, R; Cinq-Mars, D

    2015-11-01

    Microbial protein synthesis in the rumen would be optimized when dietary carbohydrates and proteins have synchronized rates and extent of degradation. The aim of this study was to evaluate the effect of varying ruminal degradation rate of energy and nitrogen sources on intake, nitrogen balance, microbial protein yield, and kinetics of nutrients in the rumen of growing kids. Eight Boer goats (38.2 ± 3.0 kg) were used. The treatments were arranged in a split-plot Latin square design with grain sources (barley or corn) forming the main plots (squares). Grain processing methods and levels of protein degradability formed the subplots in a 2 × 2 factorial arrangement for a total of 8 dietary treatments. The grain processing method was rolling for barley and cracking for corn. Levels of protein degradability were obtained by feeding untreated soybean meal (SBM) or heat-treated soybean meal (HSBM). Each experimental period lasted 21 d, consisting of a 10-d adaptation period, a 7-d digestibility determination period, and a 4-d rumen evacuation and sampling period. Kids fed with corn had higher purine derivatives (PD) excretion when coupled with SBM compared with HSBM and the opposite occurred with barley-fed kids ( ≤ 0.01). Unprocessed grain offered with SBM led to higher PD excretion than with HSBM whereas protein degradability had no effect when processed grain was fed ( ≤ 0.03). Results of the current experiment with high-concentrate diets showed that microbial N synthesis could be maximized in goat kids by combining slowly fermented grains (corn or unprocessed grains) with a highly degradable protein supplement (SBM). With barley, a more rapidly fermented grain, a greater microbial N synthesis was observed when supplementing a low-degradable protein (HSBM).

  15. Folding and membrane insertion of the pore-forming peptide gramicidin occur as a concerted process.

    Science.gov (United States)

    Hicks, Matthew R; Damianoglou, Angeliki; Rodger, Alison; Dafforn, Timothy R

    2008-11-07

    Many antibiotic peptides function by binding and inserting into membranes. Understanding this process provides an insight into the fundamentals of both membrane protein folding and antibiotic peptide function. For the first time, in this work, flow-aligned linear dichroism (LD) is used to study the folding of the antibiotic peptide gramicidin. LD provides insight into the combined processes of peptide folding and insertion and has the advantage over other similar techniques of being insensitive to off-membrane aggregation events. By combining LD data with conventional measurements of protein fluorescence and circular dichroism, the mechanism of gramicidin insertion is elucidated. The mechanism consists of five separately assignable steps that include formation of a water-insoluble gramicidin aggregate, dissociation from the aggregate, partitioning of peptide to the membrane surface, oligomerisation on the surface and concerted insertion and folding of the peptide to the double-helical form of gramicidin. Measurement of the rates of each step shows that although changes in the fluorescence signal cease 10 s after the initiation of the process, the insertion of the peptide into the membrane is actually not complete for a further 60 min. This last membrane insertion phase is only apparent by measurement of LD and circular dichroism signal changes. In summary, this study demonstrates the importance of multi-technique approaches, including LD, in studies of membrane protein folding.

  16. TOF-SIMS investigation of degradation pathways occurring in a variety of organic photovoltaic devices – the ISOS-3 inter-laboratory collaboration

    DEFF Research Database (Denmark)

    Andreasen, Birgitta; Tanenbaum, David; Hermenau, Martin

    2012-01-01

    -depth in the organic solar cells. Various degradation mechanisms were investigated and correlated with cell performance. For example, photo-oxidation of the active material was quantitatively studied as a function of cell performance. The large variety of cell architectures used (some with and some without......-destructive and destructive techniques in order to identify specific degradation mechanisms responsible for the deterioration of the photovoltaic response. Work presented herein involves time-of-flight secondary ion mass spectrometry (TOF-SIMS) in order to study chemical degradation in-plane as well as in...... of organic solar cells....

  17. Environmental persistence of pesticides and their ecotoxicity: A review of natural degradation processes

    International Nuclear Information System (INIS)

    Narvaez Valderrama, Jhon Fredy; Palacio Baena, Jaime Alberto; Molina Perez, Francisco Jose

    2012-01-01

    Pesticides are allochthonous pollutants discharged in natural environments. Once in the environment, natural factors such as biodegradation, photodegradation and chemical hydrolysis trigger partial or total pesticide transformation and reduce their environmental persistence. However, some degraded compounds have a greater ecotoxicological effect on the biota that the parent compounds and the change in the physicochemical properties increase the bioaccumulation, toxicity and transference processes. Therefore, knowledge about degradation processes in the environment is crucial in studies related to the dynamics and behavior of these substances in the environment and the impact on aquatic and terrestrial ecosystems. This review aims to show the influence of natural degradation processes on the persistence of pesticides, their ecotoxicity and dynamics. Also discuss the application of the degradation processes in water treatment and pesticides removal. While biodegradation processes have been improved by using genetically engineered microorganisms, in the photodegradation has been applied advanced oxidation technologies (TAOS) in the treatment of water contaminated with pesticides.

  18. The Formation of Chimeric Nanomorphologies, as a Reflection of Naturally Occurring Thermodynamic Processes

    Science.gov (United States)

    Naziris, N.; Demetzos, C.

    2017-11-01

    The self-assembly process of different in nature biomaterials leads to the morphogenesis of various nano-structures, where the individual molecule properties (e.g. hydrophilic-to-hydrophobic balance and elasticity), profoundly affect the intermediate surfaces’ interfacial thermodynamics. Herein, the mixing of a phospholipid and an amphiphilic block copolymer, through the thin-film hydration method, gave different morphologies, among which there were vesicles (i.e. liposomes and polymersomes), micelles and worm-like structures. The formation of such variety of structures is attributed to divergent entropic pathways, which are determined by a number of parameters, such as the lipid:polymer molar ratio and the polymer composition. The developed nanosystems are considered as chimeric/mixed, because of the two different in type biomaterials that compose them. The vesicles also exhibited membrane “irregularities”, which are connected with their biophysical behavior. Nature has “chosen” vesicular forms to be the thermodynamically stable “biological apartments”, in which life was enclosed and additionally, vesicles provided compartmentalized systems, where the intracellular environment was built. Phospholipid properties result in membranes/bilayers that harmonically assimilate other molecules, like proteins and retain their integrity and functionality, while gaining additional features. A cause that alters this relationship might induce changes in the membrane composition and morphology, with respect to lipid rafts/domains, what has been linked with the activation and development of certain human disorders/diseases. The self-assembly of two different biomaterials into various structures that present distinct membrane phenomena is believed to simulate these natural processes.

  19. Modeling Surface Processes Occurring on Moons of the Outer Solar System

    Science.gov (United States)

    Umurhan, O. M.; White, O. L.; Moore, J. M.; Howard, A. D.; Schenk, P.

    2016-12-01

    A variety of processes, some with familiar terrestrial analogs, are known to take place on moon surfaces in the outer solar system. In this talk, we discuss the observed features of mass wasting and surface transport seen on both Jupiter's moon Calisto and one of Saturn's Trojan moons Helene. We provide a number of numerical models using upgraded version of MARSSIM in support of several hypotheses suggested on behalf of the observations made regarding these objects. Calisto exhibits rolling plains of low albedo materials surrounding relatively high jutting peaks harboring high albedo deposits. Our modeling supports the interpretation that Calisto's surface is a record of erosion driven by the sublimation of CO2 and H2O contained in the bedrock. Both solar insolation and surface re-radiation drives the sublimation leaving behind debris which we interpret to be the observed darkened regolith and, further, the high albedo peaks are water ice deposits on surface cold traps. On the other hand, the 45 km scale Helene, being a milligravity environment, exhibits mysterious looking streaks and grooves of very high albedo materials extending for several kilometers with a down-sloping grade of 7o-9o. Helene's cratered terrain also shows evidence of narrowed septa. The observed surface features suggest some type of advective processes are at play in this system. Our modeling lends support to the suggestion that Helene's surface materials behave as a Bingham plastic material - our flow modeling with such rheologies can reproduce the observed pattern of streakiness depending upon the smoothness of the underlying bedrock; the overall gradients observed; and the narrowed septa of inter-crater regions.

  20. Degradation kinetics of seven organophosphorus pesticides in milk during yoghurt processing

    Directory of Open Access Journals (Sweden)

    LI-YING BO

    2011-03-01

    Full Text Available Bovine milk spiked with seven organophosphorus pesticides, i.e., dimethoate, fenthion, malathion, methyl parathion, monocrotophos, phorate and trichlorphon, was fermented at 42 °C with commercial directed vat set (DVS starters to investigate the degradation kinetics of the pesticides during yoghurt processing. The spiked pesticides were extracted from the prepared samples with an organic solvent and analyzed by gas chromatography after purification. Based on published results that the degradation kinetics of pesticides is first order, the rate constant of degradation and the half live period of the pesticides were calculated. The results indicated that degradation of the pesticides in milk during yoghurt processing were enhanced by one or both starters, except for malathion, and the two commercial DVS starters had different influences on the degradation kinetics of the pesticides.

  1. Process-induced degradation of bioresorbable PDLGA in bone tissue scaffold production.

    Science.gov (United States)

    Little, H; Clarke, S A; Cunningham, E; Buchanan, F

    2017-12-28

    Process-induced degradation of clinically relevant resorbable polymers was investigated for two thermal techniques, filament extrusion followed by fused deposition modelling (FDM). The aim was to develop a clear understanding of the relationship between temperature, processing time and resultant process-induced degradation. This acts to address the current knowledge gap in studies involving thermal processing of resorbable polymers. Poly(DL-lactide-co-glycolide) (PDLGA) was chosen for its clinically relevant resorption properties. Furthermore, a comparative study of controlled thermal exposure was conducted through compression moulding PDLGA at a selected range of temperatures (150-225 °C) and times (0.5-20 min). Differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) were used to characterise thermally induced degradation behaviour. DSC proved insensitive to degradation effects, whereas GPC demonstrated distinct reductions in molecular weight allowing for the quantification of degradation. A near-exponential pattern of degradation was identified. Through the application of statistical chain scission equations, a predictive plot of theoretical degradation was created. Thermal degradation was found to have a significant effect on the molecular weight with a reduction of up to 96% experienced in the controlled processing study. The proposed empirical model may assist prediction of changes in molecular weight, however, accuracy limitations are highlighted for twin-screw extrusion, accredited to high-shear mixing. The results from this study highlight the process sensitivity of PDLGA and proposes a methodology for quantification and prediction, which contributes to efforts in understanding the influence of manufacture on performance of degradable medical implants.

  2. Investigation of the degradation mechanism of catalytic wires during oxidation of ammonia process

    International Nuclear Information System (INIS)

    Pura, Jarosław; Wieciński, Piotr; Kwaśniak, Piotr; Zwolińska, Marta; Garbacz, Halina; Zdunek, Joanna; Laskowski, Zbigniew; Gierej, Maciej

    2016-01-01

    Highlights: • Degradation mechanisms of precious metal catalytic gauzes is proposed. • Significant change of gauzes morphology and chemical composition was observed. • Samples were analyzed using SEM, EDS and micro-XCT techniques. - Abstract: The most common catalysts for the ammonia oxidation process are 80 μm diameter platinum-rhodium wires knitted or woven into the form of a gauze. In an aggressive environment and under extreme conditions (temperature 800–900 °C, intensive gas flow, high pressure) precious elements are drained from the surface of the wires. Part of this separated material quickly decomposes on the surface in the form of characteristic “cauliflower-shape protrusions”. The rest of the platinum is captured by palladium-nickel catalytic-capture gauzes located beneath. In our investigation we focused on the effects of the degradation of gauzes from one industrial catalytic system. The aim of the study was to compare the degree and the mechanism of degradation of gauzes from a different part of the reactor. The study covered PtRh7 catalytic and PdNi5 catalytic-capture gauzes. X-ray computer microtomography investigation revealed that despite strong differences in morphology, each Pt-Rh wire has a similar specific surface area. This indicates that the oxidation process and morphological changes of the wires occur in a self-regulating balance, resulting in the value of the specific surface area of the catalyst. Microtomography analysis of Pd-Ni wires revealed strong redevelopment of the wires’ surface, which is related to the platinum capture phenomenon. Scanning electron microscope observations also revealed the nanostructure in the cauliflower-shape protrusions and large grains in the wires’ preserved cores. The high temperature in the reactor and the long-term nature of the process do not favor the occurrence of the nanostructure in this type of material. Further and detailed analysis of this phenomena will provide a better

  3. Investigation of the degradation mechanism of catalytic wires during oxidation of ammonia process

    Energy Technology Data Exchange (ETDEWEB)

    Pura, Jarosław, E-mail: jaroslawpura@gmail.com [Faculty of Material Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Wieciński, Piotr; Kwaśniak, Piotr; Zwolińska, Marta; Garbacz, Halina; Zdunek, Joanna [Faculty of Material Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Laskowski, Zbigniew; Gierej, Maciej [Precious Metal Mint, Weteranów 95, 05-250 Radzymin (Poland)

    2016-12-01

    Highlights: • Degradation mechanisms of precious metal catalytic gauzes is proposed. • Significant change of gauzes morphology and chemical composition was observed. • Samples were analyzed using SEM, EDS and micro-XCT techniques. - Abstract: The most common catalysts for the ammonia oxidation process are 80 μm diameter platinum-rhodium wires knitted or woven into the form of a gauze. In an aggressive environment and under extreme conditions (temperature 800–900 °C, intensive gas flow, high pressure) precious elements are drained from the surface of the wires. Part of this separated material quickly decomposes on the surface in the form of characteristic “cauliflower-shape protrusions”. The rest of the platinum is captured by palladium-nickel catalytic-capture gauzes located beneath. In our investigation we focused on the effects of the degradation of gauzes from one industrial catalytic system. The aim of the study was to compare the degree and the mechanism of degradation of gauzes from a different part of the reactor. The study covered PtRh7 catalytic and PdNi5 catalytic-capture gauzes. X-ray computer microtomography investigation revealed that despite strong differences in morphology, each Pt-Rh wire has a similar specific surface area. This indicates that the oxidation process and morphological changes of the wires occur in a self-regulating balance, resulting in the value of the specific surface area of the catalyst. Microtomography analysis of Pd-Ni wires revealed strong redevelopment of the wires’ surface, which is related to the platinum capture phenomenon. Scanning electron microscope observations also revealed the nanostructure in the cauliflower-shape protrusions and large grains in the wires’ preserved cores. The high temperature in the reactor and the long-term nature of the process do not favor the occurrence of the nanostructure in this type of material. Further and detailed analysis of this phenomena will provide a better

  4. Influence of dihydroxybenzenes on paracetamol and ciprofloxacin degradation and iron(III) reduction in Fenton processes.

    Science.gov (United States)

    Costa E Silva, Beatriz; de Lima Perini, João Angelo; Nogueira, Raquel F Pupo

    2017-03-01

    The degradation of paracetamol (PCT) and ciprofloxacin (CIP) was compared in relation to the generation of dihydroxylated products, Fe(III) reduction and reaction rate in the presence of dihydroxybenzene (DHB) compounds, or under irradiation with free iron (Fe 3+ ) or citrate complex (Fecit) in Fenton or photo-Fenton process. The formation of hydroquinone (HQ) was observed only during PCT degradation in the dark, which increased drastically the rate of PCT degradation, since HQ formed was able to reduce Fe 3+ and contributed to PCT degradation efficiency. When HQ was initially added, PCT and CIP degradation rate in the dark was much higher in comparison to the absence of HQ, due to the higher and faster formation of Fe 2+ at the beginning of reaction. In the absence of HQ, no CIP degradation was observed; however, when HQ was added after 30 min, the degradation rate increased drastically. Ten PCT hydroxylated intermediates were identified in the absence of HQ, which could contribute for Fe(III) reduction and consequently to the degradation in a similar way as HQ. During CIP degradation, only one product of hydroxyl radical attack on benzene ring and substitution of the fluorine atom was identified when HQ was added to the reaction medium.

  5. SEM-EDX Study of the Degradation Process of Two Xenograft Materials Used in Sinus Lift Procedures

    Directory of Open Access Journals (Sweden)

    María Piedad Ramírez Fernández

    2017-05-01

    Full Text Available Some studies have demonstrated that in vivo degradation processes are influenced by the material’s physico-chemical properties. The present study compares two hydroxyapatites manufactured on an industrial scale, deproteinized at low and high temperatures, and how physico-chemical properties can influence the mineral degradation process of material performance in bone biopsies retrieved six months after maxillary sinus augmentation. Residual biomaterial particles were examined by field scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDX to determine the composition and degree of degradation of the bone graft substitute material. According to the EDX analysis, the Ca/P ratio significantly lowered in the residual biomaterial (1.08 ± 0.32 compared to the initial composition (2.22 ± 0.08 for the low-temperature sintered group, which also presented high porosity, low crystallinity, low density, a large surface area, poor stability, and a high resorption rate compared to the high-temperature sintered material. This demonstrates that variations in the physico-chemical properties of bone substitute material clearly influence the degradation process. Further studies are needed to determine whether the resorption of deproteinized bone particles proceeds slowly enough to allow sufficient time for bone maturation to occur.

  6. A new method for defining and managing process alarms and for correcting process operation when an alarm occurs

    International Nuclear Information System (INIS)

    Brooks, Robin; Thorpe, Richard; Wilson, John

    2004-01-01

    A new mathematical treatment of alarms that considers them as multi-variable interactions between process variables has provided the first-ever method to calculate values for alarm limits. This has resulted in substantial reductions in false alarms and hence in alarm annunciation rates in field trials. It has also unified alarm management, process control and product quality control into a single mathematical framework so that operations improvement and hence economic benefits are obtained at the same time as increased process safety. Additionally, an algorithm has been developed that advises what changes should be made to Manipulable process variables to clear an alarm. The multi-variable Best Operating Zone at the heart of the method is derived from existing historical data using equation-free methods. It does not require a first-principles process model or an expensive series of process identification experiments. Integral with the method is a new format Process Operator Display that uses only existing variables to fully describe the multi-variable operating space. This combination of features makes it an affordable and maintainable solution for small plants and single items of equipment as well as for the largest plants. In many cases, it also provides the justification for the investments about to be made or already made in process historian systems. Field Trials have been and are being conducted at IneosChlor and Mallinckrodt Chemicals, both in the UK, of the new geometric process control (GPC) method for improving the quality of both process operations and product by providing Process Alarms and Alerts of much high quality than ever before. The paper describes the methods used, including a simple visual method for Alarm Rationalisation that quickly delivers large sets of Consistent Alarm Limits, and the extension to full Alert Management with highlights from the Field Trials to indicate the overall effectiveness of the method in practice

  7. A new method for defining and managing process alarms and for correcting process operation when an alarm occurs

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Robin [Curvaceous Software Limited, P.O. Box 43, Gerrards Cross, Bucks SL98UX (United Kingdom)]. E-mail: enquiries@curvaceous.com; Thorpe, Richard [Curvaceous Software Limited, P.O. Box 43, Gerrards Cross, Bucks SL98UX (United Kingdom); Wilson, John [Curvaceous Software Limited, P.O. Box 43, Gerrards Cross, Bucks SL98UX (United Kingdom)

    2004-11-11

    A new mathematical treatment of alarms that considers them as multi-variable interactions between process variables has provided the first-ever method to calculate values for alarm limits. This has resulted in substantial reductions in false alarms and hence in alarm annunciation rates in field trials. It has also unified alarm management, process control and product quality control into a single mathematical framework so that operations improvement and hence economic benefits are obtained at the same time as increased process safety. Additionally, an algorithm has been developed that advises what changes should be made to Manipulable process variables to clear an alarm. The multi-variable Best Operating Zone at the heart of the method is derived from existing historical data using equation-free methods. It does not require a first-principles process model or an expensive series of process identification experiments. Integral with the method is a new format Process Operator Display that uses only existing variables to fully describe the multi-variable operating space. This combination of features makes it an affordable and maintainable solution for small plants and single items of equipment as well as for the largest plants. In many cases, it also provides the justification for the investments about to be made or already made in process historian systems. Field Trials have been and are being conducted at IneosChlor and Mallinckrodt Chemicals, both in the UK, of the new geometric process control (GPC) method for improving the quality of both process operations and product by providing Process Alarms and Alerts of much high quality than ever before. The paper describes the methods used, including a simple visual method for Alarm Rationalisation that quickly delivers large sets of Consistent Alarm Limits, and the extension to full Alert Management with highlights from the Field Trials to indicate the overall effectiveness of the method in practice.

  8. A new method for defining and managing process alarms and for correcting process operation when an alarm occurs.

    Science.gov (United States)

    Brooks, Robin; Thorpe, Richard; Wilson, John

    2004-11-11

    A new mathematical treatment of alarms that considers them as multi-variable interactions between process variables has provided the first-ever method to calculate values for alarm limits. This has resulted in substantial reductions in false alarms and hence in alarm annunciation rates in field trials. It has also unified alarm management, process control and product quality control into a single mathematical framework so that operations improvement and hence economic benefits are obtained at the same time as increased process safety. Additionally, an algorithm has been developed that advises what changes should be made to Manipulable process variables to clear an alarm. The multi-variable Best Operating Zone at the heart of the method is derived from existing historical data using equation-free methods. It does not require a first-principles process model or an expensive series of process identification experiments. Integral with the method is a new format Process Operator Display that uses only existing variables to fully describe the multi-variable operating space. This combination of features makes it an affordable and maintainable solution for small plants and single items of equipment as well as for the largest plants. In many cases, it also provides the justification for the investments about to be made or already made in process historian systems. Field Trials have been and are being conducted at IneosChlor and Mallinckrodt Chemicals, both in the UK, of the new geometric process control (GPC) method for improving the quality of both process operations and product by providing Process Alarms and Alerts of much high quality than ever before. The paper describes the methods used, including a simple visual method for Alarm Rationalisation that quickly delivers large sets of Consistent Alarm Limits, and the extension to full Alert Management with highlights from the Field Trials to indicate the overall effectiveness of the method in practice.

  9. Degradation of amoxicillin, ampicillin and cloxacillin antibiotics in aqueous solution by the UV/ZnO photocatalytic process

    International Nuclear Information System (INIS)

    Elmolla, Emad S.; Chaudhuri, Malay

    2010-01-01

    The study examined the effect of operating conditions (zinc oxide concentration, pH and irradiation time) of the UV/ZnO photocatalytic process on degradation of amoxicillin, ampicillin and cloxacillin in aqueous solution. pH has a great effect on amoxicillin, ampicillin and cloxacillin degradation. The optimum operating conditions for complete degradation of antibiotics in an aqueous solution containing 104, 105 and 103 mg/L amoxicillin, ampicillin and cloxacillin, respectively were: zinc oxide 0.5 g/L, irradiation time 180 min and pH 11. Under optimum operating conditions, complete degradation of amoxicillin, ampicillin and cloxacillin occurred and COD and DOC removal were 23.9 and 9.7%, respectively. The photocatalytic reactions under optimum conditions approximately followed a pseudo-first order kinetics with rate constant (k) 0.018, 0.015 and 0.029 min -1 for amoxicillin, ampicillin and cloxacillin, respectively. UV/ZnO photocatalysis can be used for amoxicillin, ampicillin and cloxacillin degradation in aqueous solution.

  10. A contribution to the study of stand degradation process on the territory of Fruška Gora National Park

    Directory of Open Access Journals (Sweden)

    Bobinac Martin T.

    2003-01-01

    Full Text Available We analyzed the process of stand degradation of individual forest ecosystems in the region of the zonal community Tilio-Carpino-Qurcetum robori-cerris Jov. 79 located in the western part of Fruška Gora National Park. Degradation occurred is consequence to regeneration felling and it progressed towards the extinction of oaks, first of all the valuable pedunculate oak and Vergilius's oak, and then also Turkey oak. The analyzed mature stands were degraded coppice and mainly predominated by the Turkey oak in the tree stratum. In juvenile stands, often initially well regenerated with Turkey oak, the dominant species in the tree stratum are lime, hornbeam, flowering ash, field maple and other secondary species, predominantly of coppice origin. Restitution of the degraded stands is possible by applying an adequate regeneration system. Taking into account the primarily protective function of the analyzed forest ecosystems and the fact that these are degraded and coppice stands, the system of regeneration should be based on combined restoration.

  11. Mild degradation processes in ZnO-based varistors: the role of Zn vacancies

    Science.gov (United States)

    Ponce, M. A.; Macchi, C.; Schipani, F.; Aldao, C. M.; Somoza, A.

    2015-03-01

    The effects of a degradation process on the structural and electrical properties of ZnO-based varistors induced by the application of dc bias voltage were analysed. Capacitance and resistance measurements were carried out to electrically characterize the polycrystalline semiconductor before and after different degrees of mild degradation. Vacancies' changes in the varistors were studied with positron annihilation lifetime spectroscopy. Variations on the potential barrier height and effective doping concentration were determined by fitting the experimental data from impedance spectroscopy measurements. These results indicate two different stages in the degradation process consistent with vacancy-like concentration changes.

  12. Degradation of 2,4-dichlorophenoxyacetic acid in water by ozone-hydrogen peroxide process

    Institute of Scientific and Technical Information of China (English)

    YU Ying-hui; MA Jun; HOU Yan-jun

    2006-01-01

    This study reports an investigation into the degradation of 2,4-dichlorophenoxyacetic acid in bubble contactor column by O3/H2O2 process, which is widely used as a principal advanced oxidation process. The degradation of 2,4-dichlorophenoxyacetic acid was studied under different H2O2/O3 molar ratio and pH value. Meanwhile, TOC removal was investigated both in distilled water and tap water. The influences of ozone transfer and consumed hydrogen peroxide were also discussed. The degradation products and oxidation intermediates were identified by GC-MS and LC-MS. A possible reaction mechanism was thus proposed.

  13. Mechanisms promoting and inhibiting the process of proteasomal degradation of cells

    Directory of Open Access Journals (Sweden)

    Pedrycz Agnieszka

    2016-03-01

    Full Text Available Defects in the process of degradation of unneeded cellular proteins underlie many diseases. This article discusses one of the most important systems of removal of abnormal proteins. It describes the process of ubiquitination of proteins for proteasome degradation. It also describes the structure of the 26S and 20S proteasomes and the mechanism of ubiquitin-proteasome system. Proteasome proteolytic system is highly specialized and organized. Protease-proteasome 26S is particularly important for proper cell functioning. It recognizes and degrades marked proteins. Inhibition of proteasome pathway leads to cell cycle arrest and apoptosis.

  14. Lignocellulose Biomass: Constitutive Polymers. Biological Processes of Lignin Degradation

    International Nuclear Information System (INIS)

    Martin, C.; Manzanares, P.

    1994-01-01

    The structure of the lignocellulosic materials and the chemical composition of their main constitutive polymers, cellulose, hemicelluloses and lignin are described. The most promising transformation processes according to the type of biomass considered: hardwood, softwood an herbaceous and the perspectives of biotechnological processes for bio pulping, bio bleaching and effluents decolorisation in the paper pulp industry are also discussed. (Author) 7 refs

  15. Reliability modeling of degradation of products with multiple performance characteristics based on gamma processes

    International Nuclear Information System (INIS)

    Pan Zhengqiang; Balakrishnan, Narayanaswamy

    2011-01-01

    Many highly reliable products usually have complex structure, with their reliability being evaluated by two or more performance characteristics. In certain physical situations, the degradation of these performance characteristics would be always positive and strictly increasing. In such a case, the gamma process is usually considered as a degradation process due to its independent and non-negative increments properties. In this paper, we suppose that a product has two dependent performance characteristics and that their degradation can be modeled by gamma processes. For such a bivariate degradation involving two performance characteristics, we propose to use a bivariate Birnbaum-Saunders distribution and its marginal distributions to approximate the reliability function. Inferential method for the corresponding model parameters is then developed. Finally, for an illustration of the proposed model and method, a numerical example about fatigue cracks is discussed and some computational results are presented.

  16. Autolytic degradation of skipjack tuna during heating as affected by initial quality and processing conditions.

    Science.gov (United States)

    Stagg, Nicola J; Amato, Penny M; Giesbrecht, Francis; Lanier, Tyre C

    2012-02-01

    Several factors were studied as affecting protein degradation and texture of skipjack tuna muscle following ambient pressure thermal processing (precooking). These included degree of mushy tuna syndrome (MTS) evidenced in the raw meat, raw meat pH, abusive thawing/holding, and precooking temperature/time. Slurries and intact pieces from frozen skipjack tuna, either tempered for 2 h or thawed and held at 25 °C for 22 h (abusive treatment) were heated at temperatures ranging from 40 to 80 °C for up to 2 h, and also at 90 °C for 1 h, with or without prior adjustment of pH to 5 or 7 to favor cathepsin or calpain activity, respectively. Proteolysis of precooked samples was monitored by Lowry assay and SDS-PAGE; cooked texture of intact meat was measured using a Kramer shear press and by sensory profile analysis. Proteolysis maximally occurred in slurries of skipjack tuna muscle that had been abusively stored (22 h at 25 °C) and adjusted to pH 5 prior to heating at 55 °C. Intact pieces of tuna abusively thawed/held for 22 h with subsequent heating at 55 °C also evidenced the most proteolysis and were the least firm in texture. Raw fish that evidenced higher severity of MTS when raw displayed higher levels of proteolysis prior to cooking, which were further increased after cooking at 55 °C. The kinetic data presented here can be used to optimize processing conditions for skipjack tuna canning to minimize textural degradation and optimize quality. © 2012 Institute of Food Technologists®

  17. [Degradation of p-nitrophenol by high voltage pulsed discharge and ozone processes].

    Science.gov (United States)

    Pan, Li-li; Yan, Guo-qi; Zheng, Fei-yan; Liang, Guo-wei; Fu, Jian-jun

    2005-11-01

    The vigorous oxidation by ozone and the high energy by pulsed discharge are utilized to degrade the big hazardous molecules. And these big hazardous molecules become small and less hazardous by this process in order to improve the biodegradability. When pH value is 8-9, the concentration of p-nitrophenol solution can be degraded by 96.8% and the degradation efficiency of TOC is 38.6% by ozone and pulsed discharge treatment for 30 mins. The comparison results show that the combination treatment efficiency is higher than the separate, so the combination of ozone and pulsed discharge has high synergism. It is approved that the phenyl degradation efficiency is high and the degradation efficiency of linear molecules is relative low.

  18. Controlling of degradation effects in radiation processing of polymers. Second RCM report

    International Nuclear Information System (INIS)

    2005-08-01

    The research and development works carried out by the participants of the CRP (Coordinated Research Project) dealt with natural polymers, synthetic polymers and new techniques for better understanding of radiation degradation of polymers. It includes progress in radiation degradation of polysaccharides from agricultural products (including sodium alginate, carrageenans, chitosan and gum acacia); use of radiation-degradation for doping of conductive polymers; controlling degradation processes in artificial joint implants, surface treatment of materials and food packaging; stabilizer additives for radiation environments; surface treatment of materials; and application of specialized analytical techniques (positron annihilation spectroscopy, ESR, RBS, ERDA, NMR/isotopic-labeling) to gain improved understanding of radiation degradation effects and mechanisms. Projects within the RCM group span the spectrum from fundamental studies through specific technological applications. Participants from Czech Republic, Spain and Turkey benefited from scientific collaboration with Bulgaria on PAS

  19. Preliminary degradation process study of infectious biological waste in a 5 k W thermal plasma equipment

    International Nuclear Information System (INIS)

    Xochihua S M, M.C.

    1997-01-01

    This work is a preliminary study of infectious biological waste degradation process by thermal plasma and was made in Thermal Plasma Applications Laboratory of Environmental Studies Department of the National Institute of Nuclear Research (ININ). Infectious biological waste degradation process is realized by using samples such polyethylene, cotton, glass, etc., but the present study scope is to analyze polyethylene degradation process with mass and energy balances involved. Degradation method is realized as follow: a polyethylene sample is put in an appropriated crucible localized inside a pyrolysis reactor chamber, the plasma jet is projected to the sample, by the pyrolysis phenomena the sample is degraded into its constitutive particles: carbon and hydrogen. Air was utilized as a recombination gas in order to obtain the higher percent of CO 2 if amount of O 2 is greater in the recombination gas, the CO generation is reduced. The effluent gases of exhaust pyrolysis reactor through are passed through a heat exchanger to get cooled gases, the temperature water used is 15 Centigrade degrees. Finally the gases was tried into absorption tower with water as an absorbent fluid. Thermal plasma degradation process is a very promising technology, but is necessary to develop engineering process area to avail all advantages of thermal plasma. (Author)

  20. p-Nitrophenol degradation by electro-Fenton process: Pathway, kinetic model and optimization using central composite design.

    Science.gov (United States)

    Meijide, J; Rosales, E; Pazos, M; Sanromán, M A

    2017-10-01

    The chemical process scale-up, from lab studies to industrial production, is challenging and requires deep knowledge of the kinetic model and the reactions that take place in the system. This knowledge is also useful in order to be employed for the reactor design and the determination of the optimal operational conditions. In this study, a model substituted phenol such as p-nitrophenol was degraded by electro-Fenton process and the reaction products yielded along the treatment were recorded. The kinetic model was developed using Matlab software and was based on main reactions that occurred until total mineralization which allowed predicting the degradation pathway under this advanced oxidation process. The predicted concentration profiles of p-nitrophenol, their intermediates and by-products in electro-Fenton process were validated with experimental assays and the results were consistent. Finally, based on the developed kinetic model the degradation process was optimized using central composite design taking as key parameters the ferrous ion concentration and current density. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Degradation of acrylamide by the UV/chlorine advanced oxidation process.

    Science.gov (United States)

    Gao, Ze-Chen; Lin, Yi-Li; Xu, Bin; Pan, Yang; Xia, Sheng-Ji; Gao, Nai-Yun; Zhang, Tian-Yang; Chen, Ming

    2017-11-01

    The degradation of acrylamide (AA) during UV/chlorine advanced oxidation process (AOP) was investigated in this study. The degradation of AA was negligible during UV irradiation alone. However, AA could be effectively degraded and mineralized during UV/chlorination due to the generation of hydroxyl radicals (OH). The degradation kinetics of AA during UV/chlorination fitted the pseudo-first order kinetics with the rate constant between AA and OH radicals being determined as 2.11 × 10 9  M -1  s -1 . The degradation rate and mineralization of AA during UV/chlorination were significantly promoted at acidic conditions as well as increasing chlorine dosage. The volatile degradation products of AA during UV/chlorination were identified using gas chromatography-mass spectrometry and the degradation pathways were then proposed accordingly. The formation of disinfection by-products (DBPs) in Milli-Q water and tap water during UV/chlorination of AA was also investigated. The DBPs included chloroform, dichloroacetonitrile, trichloroacetonitrile, 2,2-dichloroacetamide and 2,2,2-trichloroacetamide. Furthermore, the variations of AA degradation during UV/chlorination in different real water samples were evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Reliability demonstration methodology for products with Gamma Process by optimal accelerated degradation testing

    International Nuclear Information System (INIS)

    Zhang, Chunhua; Lu, Xiang; Tan, Yuanyuan; Wang, Yashun

    2015-01-01

    For products with high reliability and long lifetime, accelerated degradation testing (ADT) may be adopted during product development phase to verify whether its reliability satisfies the predetermined level within feasible test duration. The actual degradation from engineering is usually a strictly monotonic process, such as fatigue crack growth, wear, and erosion. However, the method for reliability demonstration by ADT with monotonic degradation process has not been investigated so far. This paper proposes a reliability demonstration methodology by ADT for this kind of product. We first apply Gamma process to describe the monotonic degradation. Next, we present a reliability demonstration method by converting the required reliability level into allowable cumulative degradation in ADT and comparing the actual accumulative degradation with the allowable level. Further, we suggest an analytical optimal ADT design method for more efficient reliability demonstration by minimizing the asymptotic variance of decision variable in reliability demonstration under the constraints of sample size, test duration, test cost, and predetermined decision risks. The method is validated and illustrated with example on reliability demonstration of alloy product, and is applied to demonstrate the wear reliability within long service duration of spherical plain bearing in the end. - Highlights: • We present a reliability demonstration method by ADT for products with monotonic degradation process, which may be applied to verify reliability with long service life for products with monotonic degradation process within feasible test duration. • We suggest an analytical optimal ADT design method for more efficient reliability demonstration, which differs from the existed optimal ADT design for more accurate reliability estimation by different objective function and different constraints. • The methods are applied to demonstrate the wear reliability within long service duration of

  3. Degradation data analysis based on a generalized Wiener process subject to measurement error

    Science.gov (United States)

    Li, Junxing; Wang, Zhihua; Zhang, Yongbo; Fu, Huimin; Liu, Chengrui; Krishnaswamy, Sridhar

    2017-09-01

    Wiener processes have received considerable attention in degradation modeling over the last two decades. In this paper, we propose a generalized Wiener process degradation model that takes unit-to-unit variation, time-correlated structure and measurement error into considerations simultaneously. The constructed methodology subsumes a series of models studied in the literature as limiting cases. A simple method is given to determine the transformed time scale forms of the Wiener process degradation model. Then model parameters can be estimated based on a maximum likelihood estimation (MLE) method. The cumulative distribution function (CDF) and the probability distribution function (PDF) of the Wiener process with measurement errors are given based on the concept of the first hitting time (FHT). The percentiles of performance degradation (PD) and failure time distribution (FTD) are also obtained. Finally, a comprehensive simulation study is accomplished to demonstrate the necessity of incorporating measurement errors in the degradation model and the efficiency of the proposed model. Two illustrative real applications involving the degradation of carbon-film resistors and the wear of sliding metal are given. The comparative results show that the constructed approach can derive a reasonable result and an enhanced inference precision.

  4. Diamex process: hydrolytic and radiolytic degradation of the diamide extractant DMDOHEMA

    International Nuclear Information System (INIS)

    Berthon, L.; Cames, B.

    2000-01-01

    This paper deals with the hydrolysis and radiolysis of a diamide (malonamide) which is the extractant of the DIAMEX process for the extraction of minor actinides from high level liquid radioactive waste. The semi-developed formula of the malonamides investigated is RR'NCO(CHR'')CONRR' (where R, R' and R'' are alkyl or oxy-alkyl groups). The formula of the extractant molecule has been optimized and has led to DMDOHEMA (NN'-dimethyl N,N'-di-octyl hexyl-oxy-ethyl malonamide: (C 8 H 17 (CH 3 )NCO) 2 CH(C 2 H 4 OC 6 H 13 )) which is the present reference extractant for the DIAMEX process. The aim of this study was to: -identify and quantify the main DMDOHEMA degradation products; - identify the potential degradation pathways for diamides; -correlate the concentration of the identified degradation products with the extracting properties of the spent solvents to identify the most disturbing degradation products. (authors)

  5. Degradation of l-polylactide during melt processing with layered double hydroxides

    DEFF Research Database (Denmark)

    Gerds, Nathalie; Katiyar, Vimal; Koch, Christian Bender

    2012-01-01

    PLA was melt compounded in small-scale batches with two forms of laurate-modified magnesium–aluminum layered double hydroxide (Mg-Al-LDH-C12), the corresponding carbonate form (Mg-Al-LDH-CO3) and a series of other additives. Various methods were then adopted to characterize the resulting compounds...... in an effort to gain greater insights into PLA degradation during melt processing. PLA molecular weight reduction was found to vary according to the type of LDH additive. It is considered that the degree of particle dispersion and LDH exfoliation, and hence the accessibility of the hydroxide layer surfaces...... and catalytically active Mg site centers are causative factors for PLA degradation. Interestingly, the release of water under the processing conditions was found to have a rather small effect on the PLA degradation. Low loadings of sodium laurate also caused PLA degradation indicating that carboxylate chain ends...

  6. Pulse radiolysis studies concerning oxidative degradation processes in linear polymers

    International Nuclear Information System (INIS)

    Schnabel, Wolfram

    1986-01-01

    On the basis of pulse radiolysis experiments carried out with various polymers in dilute solution three modes of action of molecular oxygen, 0 2 , can be discriminated with respect to main-chain scission: (a) 0 2 acts as a promoter, (b) 0 2 acts as an inhibitor, and (c) 0 2 acts as a fixing agent for main-chain breaks. The promoting mode of action (a) is due to the inhibition of simultaneously occurring intermolecular crosslinking (DNA, polymethylvinylketone) and/or to the combination of peroxyl radicals with the subsequent formation of readily decomposing oxyl radicals (polyethylene oxide, polyacrylamide, polyvinylpyrrolidone, polyribouridylic acid, polyriboadenylic acid, polyribocytidylic acid). The inhibiting mode of action (b) pertains to the reaction of 0 2 with macroradicals that otherwise undergo main-chain rupture (amylose polymethylmethacrylate). Fixing of main-chain ruptures (mode c) becomes important, if macroradicals generated by a very fast rupture of bonds in the main-chain, are prone to recombine quickly. This mode of action was evidenced in the case of polybutenesulfone where main-chain scission involves the extrusion of small segments of the chain. (author)

  7. Clofibric acid degradation in UV254/H2O2 process: effect of temperature.

    Science.gov (United States)

    Li, Wenzhen; Lu, Shuguang; Qiu, Zhaofu; Lin, Kuangfei

    2010-04-15

    The degradation of clofibric acid (CA) in UV(254)/H(2)O(2) process under three temperature ranges, i.e. T1 (9.0-11.5 degrees C), T2 (19.0-21.0 degrees C) and T3 (29.0-30.0 degrees C) was investigated. The effects of solution constituents including NO(3)(-) and HCO(3)(-) anions, and humic acid (HA) on CA degradation were evaluated in Milli-Q waters. CA degradation behaviors were simulated with the pseudo-first-order kinetic model and the apparent rate constant (k(ap)) and half-life time (t(1/2)) were calculated. The results showed that higher temperature would favor CA degradation, and CA degradation was taken place mostly by indirect oxidation through the formation of OH radicals in UV(254)/H(2)O(2) process. In addition, the effects of both NO(3)(-) and HCO(3)(-) anions at two selected concentrations (1.0x10(-3) and 0.1 mol L(-1)) and HA (20 mg L(-1)) on CA degradation were investigated. The results showed that HA had negative effect on CA degradation, and this effect was much more apparent under low temperature condition. On the other hand, the inhibitive effect on CA degradation at both lower and higher concentrations of bicarbonate was observed, and this inhibitive effect was much more apparent at higher bicarbonate concentration and lower temperature condition. While, at higher nitrate concentration the inhibitive effect on CA degradation under three temperature ranges was observed, and with the temperature increase this negative effect was apparently weakened. However, at lower nitrate concentration a slightly positive effect on CA degradation was found under T2 and T3 conditions. Moreover, when using a real wastewater treatment plant (WWTP) effluent spiked with CA over 99% of CA removal could be achieved under 30 degrees C within only 15 min compared with 40 and 80 min under 20 and 10 degrees C respectively, suggesting a significant promotion in CA degradation under higher temperature condition. Therefore, it can be concluded that temperature plays an

  8. How can we predict microstructural changes caused by the multiscale irradiation process occurred in materials having complicated and hierarchical structures?

    International Nuclear Information System (INIS)

    Morishita, Kazunori; Watanabe, Yoshiyuki; Yoshimatsu, Jun-ichi

    2008-01-01

    Challenging efforts are discussed to establish an advanced methodology for prediction of material's property and performance changes by irradiation, which will be necessary by all means for the advanced reactor maintenance technology in the future. The changes of material's properties and performance caused by irradiation, such as irradiation-induced hardening, ductility loss, and material's degradation leading to reduction in reactor lifetime, are primarily determined by microstructural changes in materials during irradiation, where athermal lattice defects are continuously produced by collisions between an irradiating particle and a target material atom, and subsequently the defects are aggregated via diffusion in the form of dislocation loops, voids, and solute precipitation. These radiation damage processes are in essence multiscale phenomena, which involve varying time- and length-scales, from ballistic binary collisions to collective atomic motion in the thermal spike stage followed by the thermal activation process. In this report, the multiscale modeling approach is proposed to understand the processes in materials having complicated and hierarchical structures. (author)

  9. Degradation mechanism of alachlor during direct ozonation and O(3)/H(2)O(2) advanced oxidation process.

    Science.gov (United States)

    Qiang, Zhimin; Liu, Chao; Dong, Bingzhi; Zhang, Yalei

    2010-01-01

    The degradation of alachlor by direct ozonation and advanced oxidation process O(3)/H(2)O(2) was investigated in this study with focus on identification of degradation byproducts. The second-order reaction rate constant between ozone and alachlor was determined to be 2.5+/-0.1M(-1)s(-1) at pH 7.0 and 20 degrees C. Twelve and eight high-molecular-weight byproducts (with the benzene ring intact) from alachlor degradation were identified during direct ozonation and O(3)/H(2)O(2), respectively. The common degradation byproducts included N-(2,6-diethylphenyl)-methyleneamine, 8-ethyl-3,4-dihydro-quinoline, 8-ethyl-quinoline, 1-chloroacetyl-2-hydro-3-ketone-7-acetyl-indole, 2-chloro-2',6'-diacetyl-N-(methoxymethyl)acetanilide, 2-chloro-2'-acetyl-6'-ethyl-N-(methoxymethyl)-acetanilide, and two hydroxylated alachlor isomers. In direct ozonation, four more byproducts were also identified including 1-chloroacetyl-2,3-dihydro-7-ethyl-indole, 2-chloro-2',6'-ethyl-acetanilide, 2-chloro-2',6'-acetyl-acetanilide and 2-chloro-2'-ethyl-6'-acetyl-N-(methoxymethyl)-acetanilide. Degradation of alachlor by O(3) and O(3)/H(2)O(2) also led to the formation of low-molecular-weight byproducts including formic, acetic, propionic, monochloroacetic and oxalic acids as well as chloride ion (only detected in O(3)/H(2)O(2)). Nitrite and nitrate formation was negligible. Alachlor degradation occurred via oxidation of the arylethyl group, N-dealkylation, cyclization and cleavage of benzene ring. After O(3) or O(3)/H(2)O(2) treatment, the toxicity of alachlor solution examined by the Daphnia magna bioassay was slightly reduced. 2009 Elsevier Ltd. All rights reserved.

  10. Chemical Degradation and Processes of Erosion of Post-Mine Territories After Mining Exploration of Iron Ore

    Directory of Open Access Journals (Sweden)

    Agnieszka Pusz

    2017-11-01

    Full Text Available The subjects of this study were uncultivated mining waste heaps which are remnants of the territories abandoned after the exploration of iron ore. The aim of this analysis was the assessment of the influence of these objects on the soil located in the nearest surroundings, as well as estimation of the level of their degradation. It was ascertained that direct geomechanical degradation exists in the examined object, which is connected with soil profile destruction in consequence of transformation of hitherto existing geomorphological conditions, deformation of natural shape of territory, density of soil levels and deformation of the spatial layout. As a result of the examination, it was pointed out that chemical degradation as well as degradation of ecological structure occur on the analyzed territory. Progressing processes of water erosion on the side of waste heap are the consequence of improperly profiled, steep slopes causing the uncontrolled flow of rainwater, lack of flora and dense, micrograiny structure of soils which prevents the effective infiltration of water. Penetration of water into the ground causes the creation of channels which, in dry periods, can become additional pathways for the possible landslides.

  11. Effects of mechanical and chemical processes on the degradation of plastic beach debris on the island of Kauai, Hawaii

    International Nuclear Information System (INIS)

    Cooper, David A; Corcoran, Patricia L

    2010-01-01

    Plastic debris is accumulating on the beaches of Kauai at an alarming rate, averaging 484 pieces/day in one locality. Particles sampled were analyzed to determine the effects of mechanical and chemical processes on the breakdown of polymers in a subtropical setting. Scanning electron microscopy (SEM) indicates that plastic surfaces contain fractures, horizontal notches, flakes, pits, grooves, and vermiculate textures. The mechanically produced textures provide ideal loci for chemical weathering to occur which further weakens the polymer surface leading to embrittlement. Fourier transform infrared spectroscopy (FTIR) results show that some particles have highly oxidized surfaces as indicated by intense peaks in the lower wavenumber region of the spectra. Our textural analyses suggest that polyethylene has the potential to degrade more readily than polypropylene. Further evaluation of plastic degradation in the natural environment may lead to a shift away from the production and use of plastic materials with longer residence times.

  12. Degradation of energy confinement or degradation of plasma-heating. What is the main definite process for Plasma transport in stellarator?

    International Nuclear Information System (INIS)

    Fedynin, O.I.; Andryuklina, E.D.

    1995-01-01

    The analysis of plasma energy balance in stellarators and tokamaks depends on the different assumptions made and may give different and even contradictory results. When assuming full power absorption by thermal plasmas, paradoxical results can be obtained: degradation of the energy confinement time with heating power as well as degradation of plasma thermal conductivity in very short times (t<< tau:E) during power modulation experiments are deduced. On the other hand, assuming that plasma transport characteristics do not change while pain plasma parameters (density and temperature, their gradients, etc.) are kept constant, leads to conclude that heating efficiency is not unity and that it depends on both, plasma parameters and heating power. In this case no contradiction is found when analyzing plasma energy balances. In this paper the results of ECRH experiments on L-2M will be presented. The experiments were aimed to try to answer this important question. Analyses of the fast processes occurring during the switch off phase of the ECR heating, modulation of the heating power, and specific plasma decay phase, have lead to the conclusion that plasma transport characteristics remaining unchanged during fast variations of the heating power is the correct assumption. 2 refs

  13. Bio-Electron-Fenton (BEF) process driven by microbial fuel cells for triphenyltin chloride (TPTC) degradation

    Energy Technology Data Exchange (ETDEWEB)

    Yong, Xiao-Yu; Gu, Dong-Yan; Wu, Yuan-Dong [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Bioenergy Research Institute, Nanjing TECH University, Nanjing 211816 (China); Yan, Zhi-Ying [Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology, Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041 (China); Zhou, Jun; Wu, Xia-Yuan [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Bioenergy Research Institute, Nanjing TECH University, Nanjing 211816 (China); Wei, Ping [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Jia, Hong-Hua [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Bioenergy Research Institute, Nanjing TECH University, Nanjing 211816 (China); Zheng, Tao, E-mail: zhengtao@ms.giec.ac.cn [Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Nengyuan Road, Guangzhou 510640 (China); Yong, Yang-Chun, E-mail: ycyong@ujs.edu.cn [Biofuels Institute, School of the Environment, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2017-02-15

    Graphical abstract: Schematic diagram of the Bio-Electron-Fenton (BEF) process for TPTC degradation. - Highlights: • A Bio-Electro-Fenton process was performed for TPTC degradation. • TPTC removal efficiency achieved 78.32 ± 2.07% within 100 h. • The TPTC degradation rate (0.775 ± 0.021 μmol L{sup −1} h{sup −1}) was much higher than previous reports. - Abstract: The intensive use of triphenyltin chloride (TPTC) has caused serious environmental pollution. In this study, an effective method for TPTC degradation was proposed based on the Bio-Electron-Fenton process in microbial fuel cells (MFCs). The maximum voltage of the MFC with graphite felt as electrode was 278.47% higher than that of carbon cloth. The electricity generated by MFC can be used for in situ generation of H{sub 2}O{sub 2} to a maximum of 135.96 μmol L{sup −1} at the Fe@Fe{sub 2}O{sub 3(*)}/graphite felt composite cathode, which further reacted with leached Fe{sup 2+} to produce hydroxyl radicals. While 100 μmol L{sup −1} TPTC was added to the cathodic chamber, the degradation efficiency of TPTC reached 78.32 ± 2.07%, with a rate of 0.775 ± 0.021 μmol L{sup −1} h{sup −1}. This Bio-Electron-Fenton driving TPTC degradation might involve in Sn−C bonds breaking and the main process is probably a stepwise dephenylation until the formation of inorganic tin and CO{sub 2}. This study provides an energy saving and efficient approach for TPTC degradation.

  14. Degradation of clofibric acid in UV/chlorine disinfection process: kinetics, reactive species contribution and pathways.

    Science.gov (United States)

    Tang, Yuqing; Shi, Xueting; Liu, Yongze; Feng, Li; Zhang, Liqiu

    2018-02-01

    As a potential endocrine disruptor, clofibric acid (CA) was investigated in this study for its degradation kinetics and pathways in UV/chlorine process. The results showed that CA in both UV photolysis and UV/chlorine processes could be degraded via pseudo-first-order kinetics, while it almost could not be degraded in the dark chlorination process. The observed rate constant ( k obs ) in UV photolysis was 0.0078 min -1, and increased to 0.0107 min -1 combining with 0.1 mM chlorine. The k obs increased to 0.0447 min -1 with further increasing the chlorine dosage from 0.1 to 1.0 mM, and reached a plateau at higher dosage (greater than 1.0 mM). The higher k obs was obtained at acid solution rather than basic solution. Moreover, the calculated contributions of radical species to k obs indicated that the HO• contributed significantly to CA degradation in acidic conditions, while the reactive chlorine species and UV direct photolysis dominated in neutral and basic solution. The degradation of CA was slightly inhibited in the presence of [Formula: see text] (1 ∼ 50 mM), barely affected by the presence of Cl - (1 ∼ 200 mM) and greatly suppressed by humic acid (0 ∼ 5 mg l -1 ). Thirteen main degradation intermediates and three degradation pathways of CA were identified during UV/chlorine process.

  15. Bio-Electron-Fenton (BEF) process driven by microbial fuel cells for triphenyltin chloride (TPTC) degradation

    International Nuclear Information System (INIS)

    Yong, Xiao-Yu; Gu, Dong-Yan; Wu, Yuan-Dong; Yan, Zhi-Ying; Zhou, Jun; Wu, Xia-Yuan; Wei, Ping; Jia, Hong-Hua; Zheng, Tao; Yong, Yang-Chun

    2017-01-01

    Graphical abstract: Schematic diagram of the Bio-Electron-Fenton (BEF) process for TPTC degradation. - Highlights: • A Bio-Electro-Fenton process was performed for TPTC degradation. • TPTC removal efficiency achieved 78.32 ± 2.07% within 100 h. • The TPTC degradation rate (0.775 ± 0.021 μmol L"−"1 h"−"1) was much higher than previous reports. - Abstract: The intensive use of triphenyltin chloride (TPTC) has caused serious environmental pollution. In this study, an effective method for TPTC degradation was proposed based on the Bio-Electron-Fenton process in microbial fuel cells (MFCs). The maximum voltage of the MFC with graphite felt as electrode was 278.47% higher than that of carbon cloth. The electricity generated by MFC can be used for in situ generation of H_2O_2 to a maximum of 135.96 μmol L"−"1 at the Fe@Fe_2O_3_(_*_)/graphite felt composite cathode, which further reacted with leached Fe"2"+ to produce hydroxyl radicals. While 100 μmol L"−"1 TPTC was added to the cathodic chamber, the degradation efficiency of TPTC reached 78.32 ± 2.07%, with a rate of 0.775 ± 0.021 μmol L"−"1 h"−"1. This Bio-Electron-Fenton driving TPTC degradation might involve in Sn−C bonds breaking and the main process is probably a stepwise dephenylation until the formation of inorganic tin and CO_2. This study provides an energy saving and efficient approach for TPTC degradation.

  16. Bearing Degradation Process Prediction Based on the Support Vector Machine and Markov Model

    Directory of Open Access Journals (Sweden)

    Shaojiang Dong

    2014-01-01

    Full Text Available Predicting the degradation process of bearings before they reach the failure threshold is extremely important in industry. This paper proposed a novel method based on the support vector machine (SVM and the Markov model to achieve this goal. Firstly, the features are extracted by time and time-frequency domain methods. However, the extracted original features are still with high dimensional and include superfluous information, and the nonlinear multifeatures fusion technique LTSA is used to merge the features and reduces the dimension. Then, based on the extracted features, the SVM model is used to predict the bearings degradation process, and the CAO method is used to determine the embedding dimension of the SVM model. After the bearing degradation process is predicted by SVM model, the Markov model is used to improve the prediction accuracy. The proposed method was validated by two bearing run-to-failure experiments, and the results proved the effectiveness of the methodology.

  17. Effect of food processing on degradation of hexachlorocyclohexane and its isomers in milk.

    Science.gov (United States)

    Singh, Sujatha; Nelapati, Krishnaiah

    2017-03-01

    To study the effect of different food processing techniques on the degradation of organochlorine compounds (α, β, ɣ and δ hexachlorocyclohexane isomers (HCH)) residues in both natural and fortified samples of milk. Raw milk samples are collected from the local areas of Hyderabad, India. Naturally and fortified milk samples (HCH) were subjected to various food processing techniques, pasteurization (63ºC for ½ h), sterilization (121ºC for 15 min) and boiling for 5 min and analyzed by gas chromatography with electron capture detector using quick, easy, cheap, effective, rugged and safe method for multiresidue analysis of pesticides in milk with slight modification. The final mean residual concentration of pesticide in milk after heat processing and percentage of degradation were calculated with respective treatments. Heat treatments are highly effective on reduction of mean residual concentration of HCH in milk. In which Sterilization and boiling proved to be more effective in degradation of HCH isomers.

  18. THE TRANSFORMATIONAL PROCESSES INVOLVING MOTOR SKILLS THAT OCCUR UNDER THE INFLUENCE OF BASIC PRELIMINARY TRAINING IN YOUNG HANDBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Markovic Sasa

    2011-06-01

    Full Text Available The population from which we extracted a sample of 76 subjects consisted of elementary school students in Kursumlija, all male, aged 12-13, who were divided into a sub-sample consisting of 38 young handball players who took part in the training sessions of a school of handball and another sub-sample consisting of 38 non-athletes, who only took part in their regular physical education classes. The aim of the research was to determine the transformation processes involving motor skills, which occur under the influence of basic preliminary training in young handball players. The subject matter of the study was to examine whether a statistically significant increase in the level of motor skills would occur under the influence of physical exercise as part of basic preliminary training in the final as compared to the initial state. Six motor tests which define the dimensions of explosive and repetitive strength were used. The results of the research indicate that significant transformational processes involving the motor skills of young handball players occurred in the final as compared to the initial measuring, under the influence of basic preliminary training.

  19. Degradation of sodium dodecyl sulphate in water using solar driven Fenton-like advanced oxidation processes

    International Nuclear Information System (INIS)

    Bandala, Erick R.; Pelaez, Miguel A.; Salgado, Maria J.; Torres, Luis

    2008-01-01

    Synthetic wastewater samples containing a model surfactant were treated using two different Fenton-like advanced oxidation processes promoted by solar radiation; the photo-Fenton reaction and Co/PMS/UV processes. Comparison between the different experimental conditions was performed by means of the overall surfactant degradation achieved and by obtaining the initial rate in the first 15 min of reaction (IR 15 ). It was found that, for dark Fenton reaction, the maximum surfactant degradation achieved was 14% under low iron and oxidant concentration. Increasing Fenton reagents by one magnitude order, surfactant degradation achieved 63% in 60 min. The use of solar radiation improved the reaction rate by 17% under same conditions and an additional increase of 12.5% was obtained by adjusting initial pH to 2. IR 15 values for dark and irradiated Fenton reactions were 0.143 and 0.154 mmol/min, respectively, for similar reaction conditions and this value increased to 0.189 mmol/min when initial pH was adjusted. The use of the Co/PMS system allow us to determine an increase in the degradation rate, for low reaction conditions (1 mM of transition metal; 4 mM oxidant) similar to those used in dark Fenton reaction. Surfactant degradation increased from 3%, for Fenton reaction, to 44.5% in the case of Co/PMS. When solar irradiation was included in the experiments, under same reaction conditions described earlier, surfactant degradation up to 64% was achieved. By increasing Co/PMS reagent concentration by almost 9 times under irradiated conditions, almost complete (>99%) surfactant degradation was reached in 5 min. Comparing IR 15 values for Co/PMS and Co/PMS/UV, it allow us to observe that the use of solar radiation increased the degradation rate in one magnitude order when compared with dark experiments and further increase of reagent concentration increased reaction rate twice

  20. Investigation of the environmental impacts of naturally occurring radionuclides in the processing of sulfide ores for gold using gamma spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gbadago, J K; Darko, E O [Ghana Atomic Energy Commission, PO Box LG 80, Legon, Accra (Ghana); Faanhof, A [South African Nuclear Energy Corporation, PO Box 582, Pretoria 0001 (South Africa); Schandorf, C, E-mail: jgbada@yahoo.com [School of Nuclear and Allied Sciences, University of Ghana, Legon, Accra (Ghana)

    2011-09-01

    The possible environmental impacts of naturally occurring radionuclides on workers and a critical community, as a result of milling and processing sulfide ores for gold by a mining company at Bogoso in the western region of Ghana, have been investigated using gamma spectroscopy. Indicative doses for the workers during sulfide ore processing were calculated from the activity concentrations measured at both physical and chemical processing stages. The dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard indices, and radioactivity level index for tailings, for the de-silted sediments of run-off from the vicinity of the tailings dam through the critical community, and for the soils of the critical community's basic schools were calculated and found to be lower than their respective permissible limits. The environmental impact of the radionuclides is therefore expected to be low in this mining environment.

  1. Investigation of the environmental impacts of naturally occurring radionuclides in the processing of sulfide ores for gold using gamma spectrometry

    International Nuclear Information System (INIS)

    Gbadago, J K; Darko, E O; Faanhof, A; Schandorf, C

    2011-01-01

    The possible environmental impacts of naturally occurring radionuclides on workers and a critical community, as a result of milling and processing sulfide ores for gold by a mining company at Bogoso in the western region of Ghana, have been investigated using gamma spectroscopy. Indicative doses for the workers during sulfide ore processing were calculated from the activity concentrations measured at both physical and chemical processing stages. The dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard indices, and radioactivity level index for tailings, for the de-silted sediments of run-off from the vicinity of the tailings dam through the critical community, and for the soils of the critical community's basic schools were calculated and found to be lower than their respective permissible limits. The environmental impact of the radionuclides is therefore expected to be low in this mining environment.

  2. Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

    Science.gov (United States)

    Mewes, Benjamin; Hilbich, Christin; Delaloye, Reynald; Hauck, Christian

    2017-12-01

    Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity). Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

  3. Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

    Directory of Open Access Journals (Sweden)

    B. Mewes

    2017-12-01

    Full Text Available Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity. Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.

  4. Optimization of radiolytic degradation of sulfadiazine by combining Fenton and gamma irradiation processes

    International Nuclear Information System (INIS)

    Rivas-Ortiz, Iram Barbaro; Cruz-Gonzalez, German; Manduca-Artiles, Michel; Jauregui-Haza, U.J.

    2017-01-01

    Gamma radiation (GR) is a promising technique, among known advanced oxidation processes, degrading water contaminants. Nevertheless, few authors report the degradation of sulfonamides by GR, and limited information exists concerning the use of GR in the case of sulfadiazine (SDZ). The objectives of this work are (1) evaluating GR as an alternative method for treating wastewater contaminated with SDZ and examinating the intensification of GR with oxidants (H 2 O 2 or Fenton reagent). GR was performed with a high-activity 60 Co source. The gamma radiation/Fenton process gave the best result, leading to total SDZ removal and high (74.13%) pollutant mineralization. (author)

  5. Degradation of carbamazepine using hydrodynamic cavitation combined with advanced oxidation processes.

    Science.gov (United States)

    Thanekar, Pooja; Panda, Mihir; Gogate, Parag R

    2018-01-01

    Degradation of carbamazepine (CBZ), a widely detected recalcitrant pharmaceutical in sewage treatment plant (STP) effluent, has been studied in the present work using combination of hydrodynamic cavitation (HC) and advanced oxidation processes (AOPs). Due to its recalcitrant nature, it cannot be removed effectively by the conventional wastewater treatment plants (WWTPs) which make CBZ a pharmaceutical of very high environmental relevance and impact as well as stressing the need for developing new treatment schemes. In the present study, the effect of inlet pressure (3-5bar) and operating pH (3-11) on the extent of degradation have been initially studied with an objective of maximizing the degradation using HC alone. The established optimum conditions as pressure of 4bar and pH of 4 resulted in maximum degradation of CBZ as 38.7%. The combined approaches of HC with ultraviolet irradiation (HC+UV), hydrogen peroxide (HC+H 2 O 2 ), ozone (HC+O 3 ) as well as combination of HC, H 2 O 2 and O 3 (HC+H 2 O 2 +O 3 ) have been investigated under optimized pressure and operating pH. It was observed that a significant increase in the extent of degradation is obtained for the combined operations of HC+H 2 O 2 +O 3 , HC+O 3 , HC+H 2 O 2 , and HC+UV with the actual extent of degradation being 100%, 91.4%, 58.3% and 52.9% respectively. Kinetic analysis revealed that degradation of CBZ fitted into first order kinetics model for all the approaches. The processes were also compared on the basis of cavitational yield and also in terms of total treatment cost. Overall, it has been demonstrated that combined process of HC, H 2 O 2 and O 3 can be effectively used for treatment of wastewater containing CBZ. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Degradation of transgene DNA in genetically modified herbicide-tolerant rice during food processing.

    Science.gov (United States)

    Song, Shangxin; Zhou, Guanghong; Gao, Feng; Zhang, Wei; Qiu, Liangyan; Dai, Sifa; Xu, Xinglian; Xiao, Hongmei

    2011-12-01

    In order to assess the effect of food processing on the degradation of exogenous DNA components in sweet rice wine and rice crackers made from genetically modified (GM) rice (Oryza sativa L.), we developed genomic DNA extraction methods and compared the effect of different food processing procedures on DNA degradation. It was found that the purity, quantity and quality of DNA by alkaline lysis method were higher than by CTAB (cetyltrimethylammonium bromide) method. For sweet rice wine, CAMV35S (cauliflower mosaic virus 35S) promoter and NOS (nopaline synthase) terminator were degraded by the third day, whereas the exogenous gene Bar (bialaphos resistance) remained unaffected. For rice crackers, boiling, drying and microwaving contributed to the initial degradations of DNA. Baking resulted in further degradations, and frying led to the most severe changes. These results indicated that the stability of DNA in GM rice was different under different processing conditions. For sweet rice wine, Bar was most stable, followed by NOS, CAMV35S, and SPS. For rice crackers, CAMV35S was most stable, followed by SPS, NOS, and Bar. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Impact of humic acid on the photoreductive degradation of perfluorooctane sulfonate (PFOS) by UV/Iodide process.

    Science.gov (United States)

    Sun, Zhuyu; Zhang, Chaojie; Chen, Pei; Zhou, Qi; Hoffmann, Michael R

    2017-12-15

    Iodide photolysis under UV illumination affords an effective method to produce hydrated electrons (e aq - ) in aqueous solution. Therefore, UV/Iodide photolysis can be utilized for the reductive degradation of many recalcitrant pollutants. However, the effect of naturally occurring organic matter (NOM) such as humic and fulvic acids (HA/FA), which may impact the efficiency of UV/Iodide photoreduction, is poorly understood. In this study, the UV photoreductive degradation of perfluorooctane sulfonate (PFOS) in the presence of I - and HA is studied. PFOS undergoes a relatively slow direct photoreduction in pure water, a moderate level of degradation via UV/Iodide, but a rapid degradation via UV/Iodide/HA photolysis. After 1.5 h of photolysis, 86.0% of the initial [PFOS] was degraded in the presence of both I - and HA with a corresponding defluorination ratio of 55.6%, whereas only 51.7% of PFOS was degraded with a defluorination ratio of 4.4% via UV/Iodide illumination in the absence of HA. The relative enhancement in the presence of HA in the photodegradation of PFOS can be attributed to several factors: a) HA enhances the effective generation of e aq - due to the reduction of I 2 , HOI, IO 3 - and I 3 - back to I - ; b) certain functional groups of HA (i.e., quinones) enhance the electron transfer efficiency as electron shuttles; c) a weakly-bonded association of I - and PFOS with HA increases the reaction probability; and d) absorption of UV photons by HA itself produces e aq - . The degradation and defluorination efficiency of PFOS by UV/Iodide/HA process is dependent on pH and HA concentration. As pH increases from 7.0 to 10.0, the enhancement effect of HA improves significantly. The optimal HA concentration for the degradation of 0.03 mM PFOS is 1.0 mg L -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Phenol degradation by advanced Fenton process in combination with ultrasonic irradiation

    Directory of Open Access Journals (Sweden)

    F.Z. Yehia

    2015-03-01

    Full Text Available In this study, a successful degradation of phenol was achieved by means of coupling nano-sized zero-valent iron (NZVI, H2O2 and 20 kHz ultrasound irradiation. The effect of H2O2 concentration, initial pH, ultrasonic irradiation time and NZVI addition on the degradation efficiency was investigated and the kinetics of the process was discussed. The results showed that the degradation rate increased by increasing the H2O2 concentration and the irradiation time but decreased with the increase of the initial pH value. These results clearly indicate that the degradation of phenol is intensified in the presence of NZVI and H2O2, which can be attributed to enhanced production of ·−OH radicals in the system. The degradation rate in the presence of NZVI was faster than in its absence. Thus, an appropriate selection of operating conditions will lead to an economical and highly efficient technology with eventual large-scale commercial applications for the degradation of organic pollutants in aqueous effluents.

  9. Nanoencapsulation of Aloe vera in Synthetic and Naturally Occurring Polymers by Electrohydrodynamic Processing of Interest in Food Technology and Bioactive Packaging.

    Science.gov (United States)

    Torres-Giner, Sergio; Wilkanowicz, Sabina; Melendez-Rodriguez, Beatriz; Lagaron, Jose M

    2017-06-07

    This work originally reports on the use of electrohydrodynamic processing (EHDP) to encapsulate Aloe vera (AV, Aloe barbadensis Miller) using both synthetic polymers, i.e., polyvinylpyrrolidone (PVP) and poly(vinyl alcohol) (PVOH), and naturally occurring polymers, i.e., barley starch (BS), whey protein concentrate (WPC), and maltodextrin. The AV leaf juice was used as the water-based solvent for EHDP, and the resultant biopolymer solution properties were evaluated to determine their effect on the process. Morphological analysis revealed that, at the optimal processing conditions, synthetic polymers mainly produced fiber-like structures, while naturally occurring polymers generated capsules. Average sizes ranged from 100 nm to above 3 μm. As a result of their different and optimal morphology and, hence, higher AV content, PVP, in the form of nanofibers, and WPC, of nanocapsules, were further selected to study the AV stability against ultraviolet (UV) light exposure. Fourier transform infrared (FTIR) spectroscopy confirmed the successful encapsulation of AV in the biopolymer matrices, presenting both encapsulants a high chemical interaction with the bioactive components. Ultraviolet-visible (UV-vis) spectroscopy showed that, while PVP nanofibers offered a poor effect on the AV degradation during UV light exposure (∼10% of stability after 5 h), WPC nanobeads delivered excellent protection (stability of >95% after 6 h). This was ascribed to positive interactions between WPC and the hydrophilic components of AV and the inherent UV-blocking and oxygen barrier properties provided by the protein. Therefore, electrospraying of food hydrocolloids interestingly appears as a novel potential nanotechnology tool toward the formulation of more stable functional foods and nutraceuticals.

  10. Effect of anionic surfactants on the process of Fenton degradation of methyl orange.

    Science.gov (United States)

    Yang, C W; Wang, D

    2009-01-01

    Fenton process has been shown to be very successful to remove dyes from water. However, the influence of other constituents in dyeing industry wastewater, such as Sodium Dodecyl Sulphate (SDS) surfactants, has not been investigated. In this study, the effect of SDS surfactant on the kinetics of Methyl Orange degradation undergoing Fenton process was investigated. Results show that Methyl Orange degradation rate decreased as SDS concentration increased, which was attributed to the consumption of hydroxyl radicals (OH) by surfactants and the formation of Methyl Orange-SDS complex. No evidence was found that the Methyl Orange degradation pathway was affected by the presence of SDS. The kinetics modelling indicates the reaction was the first-order reaction to Methyl Orange.

  11. Degrading organic micropollutants: The next challenge in the evolution of biological wastewater treatment processes

    Directory of Open Access Journals (Sweden)

    Naresh eSinghal

    2016-05-01

    Full Text Available Global water scarcity is driving the need for identifying new water source. Wastewater could be a potential water resource if appropriate treatment technologies could be developed. One of the barriers to obtaining high quality water from wastewater arises from the presence of organic micropollutants, which are biologically active at trace levels. Removal of these compounds from wastewater by current physico-chemical technologies is prohibitively expensive. While biological treatment processes are comparatively cheap, current systems are not capable of degrading the wide range of organic micropollutants present in wastewater. As current wastewater treatment processes were developed for treating conventional pollutants present at mg/L levels, degrading the ng/L levels of micropollutants will require a different approach to system design and operation. In this paper we discuss strategies that could be employed to develop biological wastewater treatment systems capable of degrading organic micropollutants.

  12. Associations between Prenatal and Early Childhood Fish and Processed Food Intake, Conduct Problems, and Co-Occurring Difficulties.

    Science.gov (United States)

    Mesirow, Maurissa Sc; Cecil, Charlotte; Maughan, Barbara; Barker, Edward D

    2017-07-01

    Little is known about early life diet as a risk factor for early-onset persistent conduct problems (EOP CP). To investigate this, we used data from the Avon Longitudinal Study of Parents and Children, a UK-based prospective epidemiological birth cohort. 5727 mother-child pairs (49.9 % boys) monitored since pregnancy (delivery date between 1 April, 1991 and 31 December, 1992) reported intake of fish and processed foods at 32 weeks gestation and, for the child, at 3 years; EOP (n = 666) and Low conduct problem (Low CP, n = 5061) trajectories were measured from 4 to 13 years; hyperactivity and emotional difficulties were assessed in childhood (4-10 years) and early adolescence (12-13 years), in addition to potential confounding factors (family adversity, birth complications, income). Compared to Low CP, mothers of EOP children consumed less fish (p processed food (p processed food at 3 years (p processed food (vs. less than one serving/day, p processed food, and low in fish, associate with an EOP CP trajectory and co-occurring difficulties in early adolescence. As small effect size differences were found, further studies are needed to investigate the long-term impact of early unhealthy diet.

  13. Degradation of flumequine by the Fenton and photo-Fenton processes: Evaluation of residual antimicrobial activity

    International Nuclear Information System (INIS)

    Rodrigues-Silva, Caio; Maniero, Milena Guedes; Rath, Susanne; Guimarães, José Roberto

    2013-01-01

    Flumequine is a broad-spectrum antimicrobial agent of the quinolone class, and it is widely used as a veterinary drug in food-producing animals. The presence of flumequine in the environment may contribute to the development of drug resistant bacterial strains. In this study, water samples fortified with flumequine (500 μg L −1 ) were degraded using the Fenton and photo-Fenton processes. The maximum degradation efficiency for flumequine by the Fenton process was approximately 40% (0.5 mmol L −1 Fe(II), 2.0 mmol L −1 H 2 O 2 and 15 min). By applying UV radiation (photo-Fenton process), the efficiency reached more than 94% in 60 min when 0.25 mmol L −1 Fe(II) and 10.0 mmol L −1 H 2 O 2 were used. Under these conditions, the Fenton process was able to reduce the biological activity, whereas the photo-Fenton process eliminated almost all of the antimicrobial activity because it was not detected. Four byproducts with an m/z of 244, 238, 220 and 202 were identified by mass spectrometry, and a degradation pathway for flumequine was proposed. The byproducts were derived from decarboxylation and defluorination reactions and from modifications in the alkylamino chain of the fluoroquinolone. - Highlights: ► Photo-Fenton process achieved the maximum performance, degrading 94% of flumequine. ► As the flumequine concentration decreased, antimicrobial activity also decreased. ► Four byproducts with m/z of 244, 238, 220 and 202 were identified. ► A degradation pathway for flumequine was proposed

  14. Degradation of flumequine by the Fenton and photo-Fenton processes: Evaluation of residual antimicrobial activity

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues-Silva, Caio; Maniero, Milena Guedes [School of Civil Engineering, Architecture and Urbanism, University of Campinas — UNICAMP, P.O. Box 6021, CEP 13083-852, Campinas, SP (Brazil); Rath, Susanne [Chemistry Institute, University of Campinas — UNICAMP, P.O. Box 6154, CEP 13084-971, Campinas, SP (Brazil); Guimarães, José Roberto, E-mail: jorober@fec.unicamp.br [School of Civil Engineering, Architecture and Urbanism, University of Campinas — UNICAMP, P.O. Box 6021, CEP 13083-852, Campinas, SP (Brazil)

    2013-02-15

    Flumequine is a broad-spectrum antimicrobial agent of the quinolone class, and it is widely used as a veterinary drug in food-producing animals. The presence of flumequine in the environment may contribute to the development of drug resistant bacterial strains. In this study, water samples fortified with flumequine (500 μg L{sup −1}) were degraded using the Fenton and photo-Fenton processes. The maximum degradation efficiency for flumequine by the Fenton process was approximately 40% (0.5 mmol L{sup −1} Fe(II), 2.0 mmol L{sup −1} H{sub 2}O{sub 2} and 15 min). By applying UV radiation (photo-Fenton process), the efficiency reached more than 94% in 60 min when 0.25 mmol L{sup −1} Fe(II) and 10.0 mmol L{sup −1} H{sub 2}O{sub 2} were used. Under these conditions, the Fenton process was able to reduce the biological activity, whereas the photo-Fenton process eliminated almost all of the antimicrobial activity because it was not detected. Four byproducts with an m/z of 244, 238, 220 and 202 were identified by mass spectrometry, and a degradation pathway for flumequine was proposed. The byproducts were derived from decarboxylation and defluorination reactions and from modifications in the alkylamino chain of the fluoroquinolone. - Highlights: ► Photo-Fenton process achieved the maximum performance, degrading 94% of flumequine. ► As the flumequine concentration decreased, antimicrobial activity also decreased. ► Four byproducts with m/z of 244, 238, 220 and 202 were identified. ► A degradation pathway for flumequine was proposed.

  15. Improving degradation of paracetamol by integrating gamma radiation and Fenton processes.

    Science.gov (United States)

    Cruz-González, Germán; Rivas-Ortiz, Iram B; González-Labrada, Katia; Rapado-Paneque, Manuel; Chávez-Ardanza, Armando; Nuevas-Paz, Lauro; Jáuregui-Haza, Ulises J

    2016-10-14

    Degradation of paracetamol (N-(4-hydroxiphenyl)acetamide) in aqueous solution by gamma radiation, gamma radiation/H2O2 and gamma radiation/Fenton processes was studied. Parameters affecting the radiolysis of paracetamol such as radiation dose, initial concentration of pollutant, pH and initial oxidant concentration were investigated. Gamma radiation was performed using a (60)Co source irradiator. Paracetamol degradation and mineralization increased with increasing absorbed radiation dose, but decreased with increasing initial concentration of the drug in aqueous solution. The addition of H2O2 resulted in an increased effect on irradiation-driven paracetamol degradation in comparison with the performance of the irradiation-driven process alone: paracetamol removal increased from 48.9% in the absence of H2O2 to 95.2% for H2O2 concentration of 41.7 mmol/L. However, the best results were obtained with gamma radiation/Fenton process with 100% of the drug removal at 5 kGy, for optimal H2O2 and Fe(2+) concentrations at 13.9 and 2.3 mmol/L, respectively, with a high mineralization of 63.7%. These results suggest gamma radiation/H2O2 and gamma radiation/Fenton processes as promising methods for paracetamol degradation in polluted wastewaters.

  16. DEGRADATION AND PROCESSING OF PLA AND ITS APPLICATION IN FIXATION OF BONE FRACTURE

    Institute of Scientific and Technical Information of China (English)

    HUYushan; BAIDongren; 等

    1999-01-01

    PLA is presently considered as the most attractive compound for temporary therapeutic application in the biomedical field.In this paper we give an overview of the present knowledge on the degradation behavior,processing technology of PLA and its application in the fixation of bone fracture.

  17. Linking trajectories of land change, land degradation processes and ecosystem services

    NARCIS (Netherlands)

    Smiraglia, D.; Ceccarelli, T.; Bajocco, S.; Salvati, L.; Perini, L.

    2016-01-01

    Land Degradation (LD) is a complex phenomenon resulting in a progressive reduction in the capacity of providing ecosystem services (ES). Landscape transformations promoting an unsustainable use of land often reveal latent processes of LD. An evaluation carried out in respect to the different

  18. Polymer degradation in reactive ion etching and its possible application to all dry processes

    International Nuclear Information System (INIS)

    Hiraoka, H.; Welsh, L.W. Jr.

    1981-01-01

    Dry etching processes involving CF 4 -plasma and reactive ion etching become increasingly important for microcircuit fabrication techniques. In these techniques polymer degradation and etch resistance against reactive species like F atoms and CF 3 + ions are the key factors in the processes. It is well-known that classical electron beam resists like poly(methyl methacrylate) and poly(1-butene sulfone) are not suitable for dry etching processes because they degrade rapidly under these etching conditions. In order to find a correlation of etching rate and polymer structures the thickness loss of polymer films have been measured for a variety of polymer films in reactive ion etching conditions, where CF 3 + ions are the major reactive species with an accelerating potential of 500 volts. Because of its high CF 4 -plasma and reactive ion etch resistance, and because of its high electron beam sensitivity, poly(methacrylonitrile) provides a positive working electron beam resist uniquely suited for all dry processes. (author)

  19. Effect of food processing on plant DNA degradation and PCR-based GMO analysis: a review.

    Science.gov (United States)

    Gryson, Nicolas

    2010-03-01

    The applicability of a DNA-based method for GMO detection and quantification depends on the quality and quantity of the DNA. Important food-processing conditions, for example temperature and pH, may lead to degradation of the DNA, rendering PCR analysis impossible or GMO quantification unreliable. This review discusses the effect of several food processes on DNA degradation and subsequent GMO detection and quantification. The data show that, although many of these processes do indeed lead to the fragmentation of DNA, amplification of the DNA may still be possible. Length and composition of the amplicon may, however, affect the result, as also may the method of extraction used. Also, many techniques are used to describe the behaviour of DNA in food processing, which occasionally makes it difficult to compare research results. Further research should be aimed at defining ingredients in terms of their DNA quality and PCR amplification ability, and elaboration of matrix-specific certified reference materials.

  20. A validated stability-indicating RP-HPLC method for levofloxacin in the presence of degradation products, its process related impurities and identification of oxidative degradant.

    Science.gov (United States)

    Lalitha Devi, M; Chandrasekhar, K B

    2009-12-05

    The objective of current study was to develop a validated specific stability indicating reversed-phase liquid chromatographic method for the quantitative determination of levofloxacin as well as its related substances determination in bulk samples, pharmaceutical dosage forms in the presence of degradation products and its process related impurities. Forced degradation studies were performed on bulk sample of levofloxacin as per ICH prescribed stress conditions using acid, base, oxidative, water hydrolysis, thermal stress and photolytic degradation to show the stability indicating power of the method. Significant degradation was observed during oxidative stress and the degradation product formed was identified by LCMS/MS, slight degradation in acidic stress and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies and the impurity spiked solution. Good resolution between the peaks corresponds to process related impurities and degradation products from the analyte were achieved on ACE C18 column using the mobile phase consists a mixture of 0.5% (v/v) triethyl amine in sodium dihydrogen orthophosphate dihydrate (25 mM; pH 6.0) and methanol using a simple linear gradient. The detection was carried out at 294 nm. The limit of detection and the limit of quantitation for the levofloxacin and its process related impurities were established. The stressed test solutions were assayed against the qualified working standard of levofloxacin and the mass balance in each case was in between 99.4 and 99.8% indicating that the developed LC method was stability indicating. Validation of the developed LC method was carried out as per ICH requirements. The developed LC method was found to be suitable to check the quality of bulk samples of levofloxacin at the time of batch release and also during its stability studies (long term and accelerated stability).

  1. Marine ecosystem acoustics (MEA): Quantifying processes in the sea at the spatio-temporal scales on which they occur

    KAUST Repository

    Godøl, Olav Rune

    2014-07-22

    Sustainable management of fisheries resources requires quantitative knowledge and understanding of species distribution, abundance, and productivity-determining processes. Conventional sampling by physical capture is inconsistent with the spatial and temporal scales on which many of these processes occur. In contrast, acoustic observations can be obtained on spatial scales from centimetres to ocean basins, and temporal scales from seconds to seasons. The concept of marine ecosystem acoustics (MEA) is founded on the basic capability of acoustics to detect, classify, and quantify organisms and biological and physical heterogeneities in the water column. Acoustics observations integrate operational technologies, platforms, and models and can generate information by taxon at the relevant scales. The gaps between single-species assessment and ecosystem-based management, as well as between fisheries oceanography and ecology, are thereby bridged. The MEA concept combines state-of-the-art acoustic technology with advanced operational capabilities and tailored modelling integrated into a flexible tool for ecosystem research and monitoring. Case studies are presented to illustrate application of the MEA concept in quantification of biophysical coupling, patchiness of organisms, predator-prey interactions, and fish stock recruitment processes. Widespread implementation of MEA will have a large impact on marine monitoring and assessment practices and it is to be hoped that they also promote and facilitate interaction among disciplines within the marine sciences.

  2. Degradation characteristic of monoazo, diazo and anthraquinone dye by UV / H2O2 process

    Science.gov (United States)

    Abidin, Che Zulzikrami Azner; Fahmi, Muhammad Ridwan; Fazara, Md Ali Umi; Nadhirah, Siti Nurfatin

    2014-10-01

    In this study, the degradation characteristic of monoazo, diazo and anthraquinone dye by UV / H2O2 process was evaluated based on the trend of color, chemical oxygen demand (COD) and total organic carbon (TOC) removal. Three types of dyes consist of monoazo, diazo and anthraquinone dyes were used to compare the degradation mechanism of the dyes. The UV / H2O2 experiments were conducted in a laboratory scale cylindrical glass reactor operated in semi-batch mode. The UV/Vis characterization of monoazo, diazo and anthraquinone dye indicated that the rapid degradation of the dyes by UV / H2O2 process is meaningful with respect to decolourization, as a result of the azo bonds and substitute antraquinone chromophore degradation. However, this process is not efficient for aromatic amines removal. The monoazo MO was difficult to be decolorized than diazo RR120 dye, which imply that number of sulphonic groups in the dye molecules determines the reactivity with hydroxyl radical. The increased in COD removal is the evidence for oxidation and decreased in carbon content of dye molecules. TOC removal analysis shows that low TOC removal of monoazo MO and diazo RR120, as compared to anthraquinone RB19 may indicate an accumulation of by-products that are resistant to the H2O2 photolysis.

  3. Impact of process variations and long term degradation on 6T-SRAM cells

    Directory of Open Access Journals (Sweden)

    Th. Fischer

    2007-06-01

    Full Text Available In modern deep-submicron CMOS technologies voltage scaling can not keep up with the scaling of the dimensions of transistors. Therefore the electrical fields inside the transistors are not constant anymore, while scaling down the device area. The rising electrical fields bring up reliability problems, such as hot carrier injection. Also other long term degradation mechanisms like Negative Bias Temperature Instability (NBTI come into the focus of circuit design.

    Along with process device parameter variations (threshold voltage, mobility, variations due to the degradation of devices form a big challenge for designers to build circuits that both yield high under the influence of process variations and remain functional with respect to long term device drift.

    In this work we present the influence of long term degradation and process variations on the performance of SRAM core-cells and parametric yield of SRAM arrays. For different use cases we show the performance degradation depending on temperature and supply voltage.

  4. Degradation characteristic of monoazo, diazo and anthraquinone dye by UV/H2O2 process

    International Nuclear Information System (INIS)

    Abidin, Che Zulzikrami Azner; Fahmi, Muhammad Ridwan; Fazara, Md Ali Umi; Nadhirah, Siti Nurfatin

    2014-01-01

    In this study, the degradation characteristic of monoazo, diazo and anthraquinone dye by UV/H 2 O 2 process was evaluated based on the trend of color, chemical oxygen demand (COD) and total organic carbon (TOC) removal. Three types of dyes consist of monoazo, diazo and anthraquinone dyes were used to compare the degradation mechanism of the dyes. The UV/H 2 O 2 experiments were conducted in a laboratory scale cylindrical glass reactor operated in semi-batch mode. The UV/Vis characterization of monoazo, diazo and anthraquinone dye indicated that the rapid degradation of the dyes by UV/H 2 O 2 process is meaningful with respect to decolourization, as a result of the azo bonds and substitute antraquinone chromophore degradation. However, this process is not efficient for aromatic amines removal. The monoazo MO was difficult to be decolorized than diazo RR120 dye, which imply that number of sulphonic groups in the dye molecules determines the reactivity with hydroxyl radical. The increased in COD removal is the evidence for oxidation and decreased in carbon content of dye molecules. TOC removal analysis shows that low TOC removal of monoazo MO and diazo RR120, as compared to anthraquinone RB19 may indicate an accumulation of by-products that are resistant to the H 2 O 2 photolysis

  5. Current State and Development of Land Degradation Processes Based on Soil Monitoring in Slovakia

    Directory of Open Access Journals (Sweden)

    Kobza Jozef

    2017-08-01

    Full Text Available Current state and development of land degradation processes based on soil monitoring system in Slovakia is evaluated in this contribution. Soil monitoring system in Slovakia is consistently running since 1993 year in 5-years repetitions. Soil monitoring network in Slovakia is constructed using ecological principle, taking into account all main soil types and subtypes, soil organic matter, climatic regions, emission regions, polluted and non-polluted regions as well as various land use. The result of soil monitoring network is 318 sites on agricultural land in Slovakia. Soil properties are evaluated according to the main threats to soil relating to European Commission recommendation for European soil monitoring performance as follows: soil erosion and compaction, soil acidification, decline in soil organic matter and soil contamination. The most significant change has been determined in physical degradation of soils. The physical degradation was especially manifested in compacted and the eroded soils. It was determined that about 39% of agricultural land is potentially affected by soil erosion in Slovakia. In addition, slight decline in soil organic matter indicates the serious facts on evaluation and extension of soil degradation processes during the last period in Slovakia. Soil contamination is without significant change for the time being. It means the soils contaminated before soil monitoring process this unfavourable state lasts also at present.

  6. Performance and dye-degrading bacteria isolation of a hybrid membrane process

    Energy Technology Data Exchange (ETDEWEB)

    You, Sheng-Jie, E-mail: sjyou@cycu.edu.tw [Department of Bioenvironmental Engineering and R and D Center for Membrane Technology, Chung Yuan Christian University, No. 200, Rd. Chung-Pei, Chungli 320, Taiwan (China); Teng, Jun-Yu, E-mail: nickprometheus@yahoo.com.tw [Department of Civil Engineering, Chung Yuan Christian University, Chungli 320, Taiwan (China)

    2009-12-15

    Textile dyeing wastewater contains harmful compounds, which are toxic to both marine organisms and human beings if it discharged into an aquatic environmental without suitable treatment. In this study, the wastewater containing the azo dye, Reactive Black 5 (RB5), was partially treated in an anaerobic sequencing batch reactor which was further treated either in an aerobic membrane bioreactors (AOMBR) or in combined aerobic membrane bioreactor/reverse osmosis (AOMBR/RO) process. The results showed that in the anaerobic sequencing batch reactor the RB5 dye was degraded to form aromatic amine intermediate metabolites, which were further mineralized in the AOMBR. It was also observed that although all effluents from the AOMBR and AOMBR/RO processes met the Taiwan EPA's effluent criteria, irrespective of which membranes were used in the aerobic tank, the effluent from the AOMBR/RO process met the criteria for reuse for toilet flushing, landscaping, irrigation, and cooling water purposes, where as the AOMBR effluent only met the criteria for cooling water due to incomplete color removal. Five anaerobic high dye-degrading bacteria were isolated, which were identified to be the same species of Lactococcus lactis by 16S rRNA sequencing. The L. lactis showed complete degradation of RB5 and further studies showed that it can also able to degrade Reactive Red 120 and Reactive Yellow 84 efficiently within 6 h.

  7. Performance and dye-degrading bacteria isolation of a hybrid membrane process

    International Nuclear Information System (INIS)

    You, Sheng-Jie; Teng, Jun-Yu

    2009-01-01

    Textile dyeing wastewater contains harmful compounds, which are toxic to both marine organisms and human beings if it discharged into an aquatic environmental without suitable treatment. In this study, the wastewater containing the azo dye, Reactive Black 5 (RB5), was partially treated in an anaerobic sequencing batch reactor which was further treated either in an aerobic membrane bioreactors (AOMBR) or in combined aerobic membrane bioreactor/reverse osmosis (AOMBR/RO) process. The results showed that in the anaerobic sequencing batch reactor the RB5 dye was degraded to form aromatic amine intermediate metabolites, which were further mineralized in the AOMBR. It was also observed that although all effluents from the AOMBR and AOMBR/RO processes met the Taiwan EPA's effluent criteria, irrespective of which membranes were used in the aerobic tank, the effluent from the AOMBR/RO process met the criteria for reuse for toilet flushing, landscaping, irrigation, and cooling water purposes, where as the AOMBR effluent only met the criteria for cooling water due to incomplete color removal. Five anaerobic high dye-degrading bacteria were isolated, which were identified to be the same species of Lactococcus lactis by 16S rRNA sequencing. The L. lactis showed complete degradation of RB5 and further studies showed that it can also able to degrade Reactive Red 120 and Reactive Yellow 84 efficiently within 6 h.

  8. Enhanced degradation of 4-nitrophenol by microwave assisted Fe/EDTA process

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bo, E-mail: yongboliu@163.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Li Song, E-mail: ls8214@163.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zhao Yongjun, E-mail: zyjun2007@126.com [State Key Laboratory of Pollution Control and Resource Reuse, School of Life Science, Nanjing University, Nanjing 210093 (China); Wu Wenfei, E-mail: feibanana6@163.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zhang Xuxiang, E-mail: zhangxx@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of Life Science, Nanjing University, Nanjing 210093 (China); Gu Xueyuan, E-mail: xygu@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Li Ruihua, E-mail: liruihua@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Yang Shaogui, E-mail: ysg420@sina.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2010-04-15

    A microwave assisted zero-valent iron oxidation process was studied in order to investigate the synergetic effects of MW irradiation on Fe/EDTA system (Fe/EDTA/MW) treated 4-nitrophenol (4-NP) from aqueous solution. The results indicated that the thermal effect of microwave improved the removal effect of 4-NP and TOC through raising the temperature of the system, as well as the non-thermal effect generated by the interaction between the microwave and the Fe resulting in an increase in the hydrophobic character of Fe surface. During the degradation of 4-NP in Fe/EDTA/MW system, the optimum value for MW power, Fe, EDTA dosage was 400 W, 2 g and 0.4 mM, respectively. The possible pathway for degrading the 4-NP was proposed based on GC/MS and HPLC analysis of the degradation intermediates. The concentration change course of the main bio-refractory by-products, the aminophenol formed in the degradation of 4-NP suggested a more efficient degradation and mineralization in Fe/EDTA/MW system. Finally, BOD{sub 5}/COD{sub Cr} of the solution increased from 0.237 to 0.635 after reaction for 18 min, indicating that the biodegradability of wastewater was greatly improved by Fe/EDTA/MW system and would benefit to further treatment by biochemical methods.

  9. Enhanced degradation of 4-nitrophenol by microwave assisted Fe/EDTA process

    International Nuclear Information System (INIS)

    Liu Bo; Li Song; Zhao Yongjun; Wu Wenfei; Zhang Xuxiang; Gu Xueyuan; Li Ruihua; Yang Shaogui

    2010-01-01

    A microwave assisted zero-valent iron oxidation process was studied in order to investigate the synergetic effects of MW irradiation on Fe/EDTA system (Fe/EDTA/MW) treated 4-nitrophenol (4-NP) from aqueous solution. The results indicated that the thermal effect of microwave improved the removal effect of 4-NP and TOC through raising the temperature of the system, as well as the non-thermal effect generated by the interaction between the microwave and the Fe resulting in an increase in the hydrophobic character of Fe surface. During the degradation of 4-NP in Fe/EDTA/MW system, the optimum value for MW power, Fe, EDTA dosage was 400 W, 2 g and 0.4 mM, respectively. The possible pathway for degrading the 4-NP was proposed based on GC/MS and HPLC analysis of the degradation intermediates. The concentration change course of the main bio-refractory by-products, the aminophenol formed in the degradation of 4-NP suggested a more efficient degradation and mineralization in Fe/EDTA/MW system. Finally, BOD 5 /COD Cr of the solution increased from 0.237 to 0.635 after reaction for 18 min, indicating that the biodegradability of wastewater was greatly improved by Fe/EDTA/MW system and would benefit to further treatment by biochemical methods.

  10. A multiscale approach to modelling electrochemical processes occurring across the cell membrane with application to transmission of action potentials.

    Science.gov (United States)

    Richardson, G

    2009-09-01

    By application of matched asymptotic expansions, a simplified partial differential equation (PDE) model for the dynamic electrochemical processes occurring in the vicinity of a membrane, as ions selectively permeate across it, is formally derived from the Poisson-Nernst-Planck equations of electrochemistry. It is demonstrated that this simplified model reduces itself, in the limit of a long thin axon, to the cable equation used by Hodgkin and Huxley to describe the propagation of action potentials in the unmyelinated squid giant axon. The asymptotic reduction from the simplified PDE model to the cable equation leads to insights that are not otherwise apparent; these include an explanation of why the squid giant axon attains a diameter in the region of 1 mm. The simplified PDE model has more general application than the Hodgkin-Huxley cable equation and can, e.g. be used to describe action potential propagation in myelinated axons and neuronal cell bodies.

  11. Drought occurence

    Science.gov (United States)

    John W. Coulston

    2007-01-01

    Why Is Drought Important? Drought is an important forest disturbance that occurs regularly in the Western United States and irregularly in the Eastern United States (Dale and others 2001). Moderate drought stress tends to slow plant growth while severedrought stress can also reduce photosynthesis (Kareiva and others 1993). Drought can also interact with...

  12. DFN-M field characterization of sandstone for a process-based site conceptual model and numerical simulations of TCE transport with degradation.

    Science.gov (United States)

    Pierce, Amanda A; Chapman, Steven W; Zimmerman, Laura K; Hurley, Jennifer C; Aravena, Ramon; Cherry, John A; Parker, Beth L

    2018-05-01

    Plumes of trichloroethene (TCE) with degradation products occur at a large industrial site in California where TCE as a dense non-aqueous phase liquid (DNAPL) entered the fractured sandstone bedrock at many locations beginning in the late 1940s. Groundwater flows rapidly in closely spaced fractures but plume fronts are strongly retarded relative to groundwater flow velocities owing largely to matrix diffusion in early decades and degradation processes in later decades and going forward. Multiple data types show field evidence for both biotic and abiotic dechlorination of TCE and its degradation products, resulting in non-chlorinated compounds. Analyses were conducted on groundwater samples from hundreds of monitoring wells and on thousands of rock samples from continuous core over depths ranging from 6 to 426 metres below ground surface. Nearly all of the present-day mass of TCE and degradation products resides in the water-saturated, low-permeability rock matrix blocks. Although groundwater and DNAPL flow primarily occur in the fractures, DNAPL dissolution followed by diffusion and sorption readily transfers contaminant mass into the rock matrix. The presence of non-chlorinated degradation products (ethene, ethane, acetylene) and compound specific isotope analysis (CSIA) of TCE and cis-1,2-dichloroethene (cDCE) indicate at least some complete dechlorination by both biotic and abiotic pathways, consistent with the observed mineralogy and hydrogeochemistry and with published results from crushed rock microcosms. The rock matrix contains abundant iron-bearing minerals and solid-phase organic carbon with large surface areas and long contact times, suggesting degradation processes are occurring in the rock matrix. Multiple, high-resolution datasets provide strong evidence for spatially heterogeneous distributions of TCE and degradation products with varying degrees of degradation observed only when using new methods that achieve better detection of dissolved gases (i

  13. Degradation of imidacloprid using combined advanced oxidation processes based on hydrodynamic cavitation.

    Science.gov (United States)

    Patil, Pankaj N; Bote, Sayli D; Gogate, Parag R

    2014-09-01

    The harmful effects of wastewaters containing pesticides or insecticides on human and aquatic life impart the need of effectively treating the wastewater streams containing these contaminants. In the present work, hydrodynamic cavitation reactors have been applied for the degradation of imidacloprid with process intensification studies based on different additives and combination with other similar processes. Effect of different operating parameters viz. concentration (20-60 ppm), pressure (1-8 bar), temperature (34 °C, 39 °C and 42 °C) and initial pH (2.5-8.3) has been investigated initially using orifice plate as cavitating device. It has been observed that 23.85% degradation of imidacloprid is obtained at optimized set of operating parameters. The efficacy of different process intensifying approaches based on the use of hydrogen peroxide (20-80 ppm), Fenton's reagent (H2O2:FeSO4 ratio as 1:1, 1:2, 2:1, 2:2, 4:1 and 4:2), advanced Fenton process (H2O2:Iron Powder ratio as 1:1, 2:1 and 4:1) and combination of Na2S2O8 and FeSO4 (FeSO4:Na2S2O8 ratio as 1:1, 1:2, 1:3 and 1:4) on the extent of degradation has been investigated. It was observed that near complete degradation of imidacloprid was achieved in all the cases at optimized values of process intensifying parameters. The time required for complete degradation of imidacloprid for approach based on hydrogen peroxide was 120 min where as for the Fenton and advance Fenton process, the required time was only 60 min. To check the effectiveness of hydrodynamic cavitation with different cavitating devices, few experiments were also performed with the help of slit venturi as a cavitating device at already optimized values of parameters. The present work has conclusively established that combined processes based on hydrodynamic cavitation can be effectively used for complete degradation of imidacloprid. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Recent development of VUV-based processes for air pollutants degradation

    Directory of Open Access Journals (Sweden)

    Haibao eHuang

    2016-03-01

    Full Text Available As air pollution become more and more serious nowadays, it is essential to find out a way to efficiently degrade the air pollutants. Vacuum ultraviolet (VUV-based processes are an emerging and promising technologies for environmental remediation such as air cleaning, wastewater treatment and air/water disinfection. With VUV irradiation, photolysis, photocatalyst is and ozone-assisted oxidation are involved at the same time, resulting in the fast degradation of air pollutants because of their strong oxidizing capacity. The mechanisms of how the oxidants are produced and reacted are discussed in this review. This paper mainly focuses on the three VUV-based oxidation processes including VUV photolysis, VUV combined with ozone-assisted oxidation and VUV-PCO with emphasis on their mechanisms and applications. Also, the outlooks of these processes are outlined in this paper.

  15. SIMULTANEOUS DEGRADATION OF SOME PHTHALATE ESTERS UNDER FENTON AND PHOTO-FENTON OXIDATION PROCESSES

    Directory of Open Access Journals (Sweden)

    BELDEAN-GALEA M.S.

    2015-03-01

    Full Text Available In this study the assessment of the degradation efficiency of five phthalates, DEP, BBP, DEHP, DINP and DIDP, found in a mixture in a liquid phase, using the Fenton and Photo Fenton oxidation processes, was conducted. It was observed that the main parameters that influence the Fenton oxidative processes of phthalates were the concentration of the oxidizing agent, H2O2, the concentration of the catalyst used, Fe2+, the pH value, UV irradiation and the reaction time. For the Fenton oxidative process, the highest degradation efficiencies were 19% for DEP, 50% for BBP, 84% for DEHP, 90% for DINP and 48% for DIDP, when the experiments were carried out using concentrations of 20 mg L-1 phthalate mixture, 100 mg L-1 H2O2, 10 mg L-1 Fe2+ at a pH value of 3, with a total reaction time of 30 minutes. For the Photo-Fenton oxidative process carried out in the same conditions as Fenton oxidative process, it was observed that after an irradiation time of 90 minutes under UV radiation the degradation efficiencies of phthalates were improved, being 22% for DEP, 71% for BBP, 97% for DEHP, 97% for DINP and 81% for DIDP.

  16. Enhanced Expression of Interferon-γ-Induced Antigen-Processing Machinery Components in a Spontaneously Occurring Cancer

    Directory of Open Access Journals (Sweden)

    Fulvia Cerruti

    2007-11-01

    Full Text Available In human tumors, changes in the surface expression and/or function of major histocompatibility complex (MHC class I antigens are frequently found and may provide malignant cells with a mechanism to escape control of the immune system. This altered human lymphocyte antigen (HLA class I phenotype can be caused by either structural alterations or dysregulation of genes encoding subunits of HLA class I antigens and/or components of the MHC class I antigen-processing machinery (APM. Herein we analyze the expression of several proteins involved in the generation of MHC class I epitopes in feline injection site sarcoma, a spontaneously occurring tumor in cats that is an informative model for the study of tumor biology in other species, including humans. Eighteen surgically removed primary fibrosarcoma lesions were analyzed, and an enhanced expression of two catalytic subunits of immunoproteasomes, PA28 and leucine aminopeptidase, was found in tumors compared to matched normal tissues. As a functional counterpart of these changes in protein levels, proteasomal activities were increased in tissue extracts from fibrosarcomas. Taken together, these results suggest that alterations in the APM system may account for reduced processing of selected tumor antigens and may potentially provide neoplastic fibroblasts with a mechanism for escape from T-cell recognition and destruction.

  17. Relationship between fiber degradation and residence time distribution in the processing of long fiber reinforced thermoplastics

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Long fiber reinforced thermoplastics (LFT were processed by in-line compounding equipment with a modified single screw extruder. A pulse stimulus response technique using PET spheres as the tracer was adopted to obtain residence time distribution (RTD of extrusion compounding. RTD curves were fitted by the model based on the supposition that extrusion compounding was the combination of plug flow and mixed flow. Characteristic parameters of RTD model including P the fraction of plug flow reactor (PFR and d the fraction of dead volume of continuous stirred tank reactor (CSTR were used to associate with fiber degradation presented by fiber length and dispersion. The effects of screw speed, mixing length and channel depth on RTD curves, and characteristic parameters of RTD models as well as their effects on the fiber degradation were investigated. The influence of shear force with different screw speeds and variable channel depth on fiber degradation was studied and the main impetus of fiber degradation was also presented. The optimal process for obtaining the balance of fiber length and dispersion was presented.

  18. Risk-associated health disorders occuring in junior schoolchildren who attend schools with higher stress and intensity of educational process

    Directory of Open Access Journals (Sweden)

    N.V. Zaitseva

    2017-03-01

    Full Text Available We performed comparative sanitary-hygienic assessment of regime, stress and intensity of educational process in different educational establishments, a comprehensive secondary school and an innovative educational establishment - lyceum. We detected that studying regime tended to be tight, classes were longer and more intense than in an ordinary school, and educational process involved considerable intellectual, sensory and emotional loads for children; such loads reached "1st category intense" level. Schoolchildren attending lyceums are also busy with additional educational programs and it significantly increases length of total educational load on them. By the end of a school year 20% of lyceum pupils suffer from sympathoadrenal system overstress and it doesn't only determine emotional tonus level in children but also leads to disorders in concentration and decision-making speed, lower reading speed and articulation, slower motor reactions. 15% of lyceum pupils have higher activity of autonomous nervous system and lower adaptation of cardiovascular system to psycho emotional and physical loads. Lyceum pupils also run 2.5 times higher risk of chronic nervous system diseases evolvement than school children attending ordinary schools. Autonomous nervous system disorders, posture disorders and nutrition disorders are predominant nosologic pathology forms in lyceum pupils as they occur in them 1.6-2.9 times more frequent than in schoolchildren of the same age who attend an ordinary comprehensive school. We detected direct correlation between higher intellectual and emotional components of educational process, and total educational intensity as well, and frequency of autonomous system disorders and musculoskeletal system diseases in pupils.

  19. Study of the degradation of organic molecules complexing radionuclides by using Advanced Oxidation Processes

    International Nuclear Information System (INIS)

    Rekab, K.

    2014-01-01

    This research thesis reports the study of the application of two AOPs (Advanced Oxidation Processes) to degrade and mineralise organic molecules which are complexing radio-elements, and thus to allow their concentrations by trapping on mineral matrices. EDTA (ethylene diamine tetraacetic acid) is chosen as reference organic complexing agent for preliminary tests performed with inactive cobalt 59 before addressing actual nuclear effluents with active cobalt 60. The author first presents the industrial context (existing nuclear wastes, notably liquid effluents and their processing) and proposes an overview of the state of the art on adsorption and precipitation of cobalt (natural and radioactive isotope). Then, the author presents the characteristics of the various studied oxides, the photochemical reactor used to perform tests, experimental techniques and operational modes. Results are then presented regarding various issues: adsorption of EDTA and the Co-EDTA complex, and cobalt precipitation; determination of the lamp photon flow by chemical actinometry and by using the Keitz method; efficiency of different processes (UV, UV/TiO 2 , UV/H 2 O 2 ) to degrade EDTA and to degrade the Co-EDTA complex; processing of a nuclear effluent coming from La Hague pools with determination of decontamination factors

  20. COMPARISON OF DIFFERENT ADVANCED OXIDATION PROCESSES DEGRADING P-CHLOROPHENOL IN AQUEOUS SOLUTION

    Directory of Open Access Journals (Sweden)

    H. Movahedyan ، A. M. Seid Mohammadi ، A. Assadi

    2009-07-01

    Full Text Available In present study, degradation of p-chlorophenol using several oxidation systems involving advanced oxidation processes such as ultraviolet/H2O2, microwave/H2O2 and both in the absence of hydrogen peroxide in batch mode by photolytic pilot plant and modified domestic microwave oven was evaluated. The oxidation rate was influenced by many factors, such as the pH value, the amount of hydrogen peroxide, irradiation time and microwave power. The optimum conditions obtained for the best degradation rate were pH=7 and H2O2 concentration of 0.05 mol/L for ultraviolet/H2O2 system and pH=10.5, H2O2 concentration of about 0.1 mol/L and microwave irradiation power of about 600W for microwave/H2O2 system at constant p-chlorophenol concentration. The degradation of p-chlorophenol by different types of oxidation processes followed first order rate decay kinetics. The rate constants were 0.137, 0.012, 0.02 and 0.004/min1 for ultraviolet/H2O2, microwave/H2O2, ultraviolet and microwave irradiation alone. Finally a comparison of the specific energy consumption showed that ultraviolet/H2O2 process reduced the energy consumption by at least 67% compared with the microwave/H2O2 process.

  1. Optimization of nonlinear, non-Gaussian Bayesian filtering for diagnosis and prognosis of monotonic degradation processes

    Science.gov (United States)

    Corbetta, Matteo; Sbarufatti, Claudio; Giglio, Marco; Todd, Michael D.

    2018-05-01

    The present work critically analyzes the probabilistic definition of dynamic state-space models subject to Bayesian filters used for monitoring and predicting monotonic degradation processes. The study focuses on the selection of the random process, often called process noise, which is a key perturbation source in the evolution equation of particle filtering. Despite the large number of applications of particle filtering predicting structural degradation, the adequacy of the picked process noise has not been investigated. This paper reviews existing process noise models that are typically embedded in particle filters dedicated to monitoring and predicting structural damage caused by fatigue, which is monotonic in nature. The analysis emphasizes that existing formulations of the process noise can jeopardize the performance of the filter in terms of state estimation and remaining life prediction (i.e., damage prognosis). This paper subsequently proposes an optimal and unbiased process noise model and a list of requirements that the stochastic model must satisfy to guarantee high prognostic performance. These requirements are useful for future and further implementations of particle filtering for monotonic system dynamics. The validity of the new process noise formulation is assessed against experimental fatigue crack growth data from a full-scale aeronautical structure using dedicated performance metrics.

  2. Assessment and Measurements of Degradation Processes in the Engineering Barriers of LILW Repository

    International Nuclear Information System (INIS)

    Zeleznik, N.; Sajna, A.; Petkovsek, B.

    2013-01-01

    In 2009 the Slovenian national agency for radwaste management (ARAO) adopted the national spatial plan for the low and intermediate level waste (LILW) repository to be located in Krsko municipality near NPP Krsko. The selected option for disposal was based on a silo type structure for the near surface disposal facility that will be situated close to a saturated aquifer. The soil in the region can be described as silt that extends a few hundred meters deep. The silt also contains sections of sand or clay. As the possibility exists that the natural geological barrier system will not be able to contain radionuclide migration it is a pre requisite that the proposed LILW repository must install engineered barriers. Research on different cementation materials are currently underway in order to find sustainable materials for the manufacturing of engineered barriers for the repository (silo, backfilling, concrete containers). The research also includes the assessment of possible site specific degradation processes in order to provide a methodology for the selection of appropriate locally available materials that will minimize the degradation processes. The research methodology was based on studying the characteristics (workability, compressive strength), durability (resistance to penetration of water, freeze/thaw resistance, resistance to groundwater), rheology (heat of hydration, autogenous and concrete shrinkage) and reinforcement corrosion of different concrete compositions. The characterization results were used to develop a numerical model for degradation processes to be found in the current concrete compositions. Although initial results indicated that the current concrete compositions are satisfactory, the research must be extended to the addition of binder materials to improve the characteristics of the manufactures concrete before degradation processes can be studied. (author)

  3. Interaction of Degradation, Deformation and Transport Processes in Municipal Solid Waste Landfills

    OpenAIRE

    Bente, Sonja

    2010-01-01

    In this thesis a model for the complex interactions between deformation, degradation and transport processe in municipal solid waste landfills is presented. Key aspects of the model are a joint continuum mechanical framework and a monolithic solution of the governing equations within the Theory of Porous Media. Interactions are considered by coupling the governing physical fields over the domain of a representative elementary volume via selected state variables. A simplified two-stage degrada...

  4. "Slight" of hand: the processing of visually degraded gestures with speech.

    Science.gov (United States)

    Kelly, Spencer D; Hansen, Bruce C; Clark, David T

    2012-01-01

    Co-speech hand gestures influence language comprehension. The present experiment explored what part of the visual processing system is optimized for processing these gestures. Participants viewed short video clips of speech and gestures (e.g., a person saying "chop" or "twist" while making a chopping gesture) and had to determine whether the two modalities were congruent or incongruent. Gesture videos were designed to stimulate the parvocellular or magnocellular visual pathways by filtering out low or high spatial frequencies (HSF versus LSF) at two levels of degradation severity (moderate and severe). Participants were less accurate and slower at processing gesture and speech at severe versus moderate levels of degradation. In addition, they were slower for LSF versus HSF stimuli, and this difference was most pronounced in the severely degraded condition. However, exploratory item analyses showed that the HSF advantage was modulated by the range of motion and amount of motion energy in each video. The results suggest that hand gestures exploit a wide range of spatial frequencies, and depending on what frequencies carry the most motion energy, parvocellular or magnocellular visual pathways are maximized to quickly and optimally extract meaning.

  5. Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

    International Nuclear Information System (INIS)

    2014-01-01

    The objective of this project is to develop a fundamental understanding of the mechanisms that limit materials durability for very high-temperature applications. Current design limitations are based on material strength and corrosion resistance. This project will characterize the interactions of high-temperature creep, fatigue, and environmental attack in structural metallic alloys of interest for the very high-temperature gas-cooled reactor (VHTR) or Next Generation Nuclear Plant (NGNP) and for the associated thermo-chemical processing systems for hydrogen generation. Each of these degradation processes presents a major materials design challenge on its own, but in combination, they can act synergistically to rapidly degrade materials and limit component lives. This research and development effort will provide experimental results to characterize creep-fatigue-environment interactions and develop predictive models to define operation limits for high-temperature structural material applications. Researchers will study individually and in combination creep-fatigue-environmental attack processes in Alloys 617, 230, and 800H, as well as in an advanced Ni-Cr oxide dispersion strengthened steel (ODS) system. For comparison, the study will also examine basic degradation processes in nichrome (Ni-20Cr), which is a basis for most high-temperature structural materials, as well as many of the superalloys. These materials are selected to represent primary candidate alloys, one advanced developmental alloy that may have superior high-temperature durability, and one model system on which basic performance and modeling efforts can be based. The research program is presented in four parts, which all complement each other. The first three are primarily experimental in nature, and the last will tie the work together in a coordinated modeling effort. The sections are (1) dynamic creep-fatigue-environment process, (2) subcritical crack processes, (3) dynamic corrosion crack

  6. Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, James; Gewirth, Andrew; Sehitoglu, Huseyin; Sofronis, Petros; Robertson, Ian

    2014-01-16

    The objective of this project is to develop a fundamental understanding of the mechanisms that limit materials durability for very high-temperature applications. Current design limitations are based on material strength and corrosion resistance. This project will characterize the interactions of high-temperature creep, fatigue, and environmental attack in structural metallic alloys of interest for the very high-temperature gas-cooled reactor (VHTR) or Next–Generation Nuclear Plant (NGNP) and for the associated thermo-chemical processing systems for hydrogen generation. Each of these degradation processes presents a major materials design challenge on its own, but in combination, they can act synergistically to rapidly degrade materials and limit component lives. This research and development effort will provide experimental results to characterize creep-fatigue-environment interactions and develop predictive models to define operation limits for high-temperature structural material applications. Researchers will study individually and in combination creep-fatigue-environmental attack processes in Alloys 617, 230, and 800H, as well as in an advanced Ni-Cr oxide dispersion strengthened steel (ODS) system. For comparison, the study will also examine basic degradation processes in nichrome (Ni-20Cr), which is a basis for most high-temperature structural materials, as well as many of the superalloys. These materials are selected to represent primary candidate alloys, one advanced developmental alloy that may have superior high-temperature durability, and one model system on which basic performance and modeling efforts can be based. The research program is presented in four parts, which all complement each other. The first three are primarily experimental in nature, and the last will tie the work together in a coordinated modeling effort. The sections are (1) dynamic creep-fatigue-environment process, (2) subcritical crack processes, (3) dynamic corrosion – crack

  7. Metabolomics of the Bio-Degradation Process of Aflatoxin B1 by Actinomycetes at an Initial pH of 6.0

    Directory of Open Access Journals (Sweden)

    Manal Eshelli

    2015-02-01

    Full Text Available Contamination of food and feed by Aflatoxin B1 (AFB1 is a cause of serious economic and health problems. Different processes have been used to degrade AFB1. In this study, biological degradation of AFB1 was carried out using three Actinomycete species, Rhodococcus erythropolis ATCC 4277, Streptomyces lividans TK 24, and S. aureofaciens ATCC 10762, in liquid cultures. Biodegradation of AFB1 was optimised under a range of temperatures from 25 to 40 °C and pH values of 4.0 to 8.0. An initial concentration of 20 µg/mL of AFB1 was used in this study. The amount of AFB1 remaining was measured against time by thin layer chromatography (TLC and high-performance liquid chromatography (HPLC, coupled with UV and mass spectrometry (LC-MS. All species were able to degrade the AFB1, and no significant difference was found between them. AFB1 remained in the liquid culture for R. erythropolis, S. lividans and S. aureofaciens were 0.81 µg/mL, 2.41 µg/mL and 2.78 µg/mL respectively, at the end of the first 24 h. Degradation occurred at all incubation temperatures and the pH with the optimal conditions for R. erythropolis was achieved at 30 °C and pH 6, whereas for S. lividans and S. aureofaciens the optimum conditions for degradation were 30 °C and pH 5. Analysis of the degradative route indicated that each microorganism has a different way of degrading AFB1. The metabolites produced by R. erythropolis were significantly different from the other two microorganisms. Products of degradation were identified through metabolomic studies by utilizing high-resolution mass spectral data. Mass spectrometric analysis indicated that the degradation of AFB1 was associated with the appearance of a range of lower molecular weight compounds. The pathway of degradation or chemical alteration of AFB1 was followed by means of high resolution Fourier transform mass spectrometry (HR-FTMS analysis as well as through the MS2 fragmentation to unravel the degradative pathway for

  8. Impact of vacuum cooking process on the texture degradation of selected apple cultivars.

    Science.gov (United States)

    Bourles, E; Mehinagic, E; Courthaudon, J L; Jourjon, F

    2009-01-01

    Thermal treatments are known to affect the textural properties of fruits and vegetables. This study was conducted to evaluate the influence of vacuum cooking process on the mechanical properties of various apple cultivars. A total of 10 apple cultivars were industrially processed by vacuum pasteurization at 95 degrees C for 25 min. The raw material was characterized by penetrometry, uniaxial double compression, soluble solid content, and titrable acidity. Textural properties of processed apples were analyzed by uniaxial double compression. As expected, for all cultivars, fruit resistance was lower after processing than before. Results showed that texture degradation due to vacuum pasteurization was different from one cultivar to another. Indeed, some cultivars, initially considered as the most resistant ones, such as Braeburn, were less suitable for processing, and became softer than others after thermal treatment. Consequently, it is worth noting that the texture classification of the investigated apple cultivars was changed by the vacuum-cooking process.

  9. Photo-assisted Fenton type processes for the degradation of phenol: A kinetic study

    International Nuclear Information System (INIS)

    Kusic, Hrvoje; Koprivanac, Natalija; Bozic, Ana Loncaric; Selanec, Iva

    2006-01-01

    In this study the application of advanced oxidation processes (AOPs), dark Fenton and photo-assisted Fenton type processes; Fe 2+ /H 2 O 2 , Fe 3+ /H 2 O 2 , Fe 0 /H 2 O 2 , UV/Fe 2+ /H 2 O 2 , UV/Fe 3+ /H 2 O 2 and UV/Fe 0 /H 2 O 2 , for degradation of phenol as a model organic pollutant in the wastewater was investigated. A detail kinetic modeling which describes the degradation of phenol was performed. Mathematical models which predict phenol decomposition and formation of primary oxidation by-products: catechol, hydroquinone and benzoquinone, by applied processes were developed. The study also consist the modeling of mineralization kinetic of the phenol solution by applied AOPs. This part, besides well known reactions of Fenton and photo-Fenton chemistry, involves additional reactions which describe removal of iron from catalytic cycle through formation of ferric complexes and its regeneration induced by UV radiation. Phenol decomposition kinetic was monitored by HPLC analysis and total organic carbon content measurements (TOC). Complete phenol removal was obtained by all applied processes. Residual TOC by applied Fenton type processes ranged between 60.2 and 44.7%, while the efficiency of those processes was significantly enhanced in the presence of UV light, where residual TOC ranged between 15.2 and 2.4%

  10. Development of process simulation code for reprocessing plant and process analysis for solvent degradation and solvent washing waste

    International Nuclear Information System (INIS)

    Tsukada, Tsuyoshi; Takahashi, Keiki

    1999-01-01

    We developed a process simulation code for an entire nuclear fuel reprocessing plant. The code can be used on a PC. Almost all of the equipment in the reprocessing plant is included in the code and the mass balance model of each item of equipment is based on the distribution factors of flow-out streams. All models are connected between the outlet flow and the inlet flow according to the process flow sheet. We estimated the amount of DBP from TBP degradation in the entire process by using the developed code. Most of the DBP is generated in the Pu refining process by the effect of α radiation from Pu, which is extracted in a solvent. On the other hand, very little of DBP is generated in the U refining process. We therefore propose simplification of the solvent washing process and volume reduction of the alkali washing waste in the U refining process. The first Japanese commercial reprocessing plant is currently under construction at Rokkasho Mura, Recently, for the sake of process simplification, the original process design has been changed. Using our code, we analyzed the original process and the simplified process. According our results, the volume of alkali waste solution in the low-level liquid treatment process will be reduced by half in the simplified process. (author)

  11. Model calculations of the chemical processes occurring in the plume of a coal-fired power plant

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, J F; Luria, M

    1982-02-01

    Computer simulations of the homogeneous, gas phase chemical reactions which occur in the plume of a coal-fired power plant were conducted in an effort to understand the influence of various environmental parameters on the production of secondary pollutants. Input data for the model were selected to reproduce the dilution of a plume from a medium-sized power plant. The environmental conditions chosen were characteristic of those found during mid-August in the south-eastern United States. Under most conditions examined, it was found that hydroxyl radicals were the most important species in the homogeneous conversion of stack gases into secondary pollutants. Other free radicals, such as HO/sub 2/ and CH/sub 3/O/sub 2/, exceeded the contribution of HO radicals only when high background hydrocarbon concentrations are used. The conversion rates calculated for the oxidation of SO/sub 2/ to SO/sub 4//sup 2 -/ in these plumes were consistent with those determined experimentally. The concentrations and relative proportions of NO/sub x/ (from the power plant) and reactive hydrocarbons (from the background air) determine, to a large extent, the plume reactivity. Free radical production is suppressed during the initial stages of dilution due to the high NO/sub x/ levels. Significant dilution is required before a suitable mix is attained which can sustain the free radical chain processes common to smog chemistry. In most cases, the free radical concentrations were found to pass through maxima and return to background levels. Under typical summertime conditions, the hyroxyl radical concentration was found to reach a maximum at a HC/NO/sub x/ ratio of approximately 20.

  12. Decolorization and degradation of reactive dye during the dyed cotton fabric rinsing process.

    Science.gov (United States)

    Luo, Deng-Hong; Zheng, Qing-Kang; Chen, Sheng; Liu, Qing-Shu; Wang, Xiu-Xing; Guan, Yu; Pu, Zong-Yao

    2010-01-01

    Dyeing process of textile consumes large quantities of water, which results in huge amounts of colored wastewater. Most of the dye wastewater treating methods focused on the treatment of wastewater after the rinsing process of dyed textile. In this paper, tetraacetylethylenediamine/hydrogen peroxide (TAED/H₂O₂) active oxidation (AO) system was developed to rinse dyed textile and decolorize the rinsing wastewater simultaneously. The results indicated that the decolorization ratio of the rinse effluent obtained by AO method were in the range of 51.72%-84.15% according to different dyes and the COD value decreased more than 30% compared with that of traditional rinsing process. The decolorization kinetics investigation showed that the decolorization of dyes during AO rinsing process followed the law of pseudo-first order kinetics. The result of UV-Vis and UPLC-MS analysis demonstrated that the dye was degraded into colorless organic molecular fragments and partly mineralized during the AO rinsing process.

  13. Human macrophage foam cells degrade atherosclerotic plaques through cathepsin K mediated processes

    DEFF Research Database (Denmark)

    Barascuk, Natasha; Skjøt-Arkil, Helene; Register, Thomas C

    2010-01-01

    BACKGROUND: Proteolytic degradation of Type I Collagen by proteases may play an important role in remodeling of atherosclerotic plaques, contributing to increased risk of plaque rupture.The aim of the current study was to investigate whether human macrophage foam cells degrade the extracellular...... matrix (ECM) of atherosclerotic plaques by cathepsin K mediated processes. METHODS: We 1) cultured human macrophages on ECM and measured cathepsin K generated fragments of type I collagen (C-terminal fragments of Type I collagen (CTX-I) 2) investigated the presence of CTX-I in human coronary arteries......-I in areas of intimal hyperplasia and in shoulder regions of advanced plaques. Treatment of human monocytes with M-CSF or M-CSF+LDL generated macrophages and foam cells producing CTX-I when cultured on type I collagen enriched matrix. Circulating levels of CTX-I were not significantly different in women...

  14. A spatial dynamic model to assess piospheric land degradation processes of SW Iberian rangelands

    Science.gov (United States)

    Herguido Sevillano, Estela; Ibáñez, Javier; Francisco Lavado Contador, Joaquín; Pulido-Fernández, Manuel; Schnabel, Susanne

    2015-04-01

    Iberian open wooded rangelands (known as dehesas or montados) constitute valuable agro-silvo-pastoral systems traditionally considered as highly sustainable. Nevertheless, in the recent decades, those systems are undergoing changes of land use and management practices that compromise its sustainability. Some of those changes, as the rising construction of watering points and the high spatial fragmentation and livestock movement restriction associated to fencing, show an aggregated effect with livestock, producing an impact gradient over soil and vegetation. Soil compaction related to livestock pressure is higher around watering points, with bare soil halos and patches of scarce vegetation or nude soil developing with higher frequency in areas close to them. Using the freeware Dinamica EGO as environmental modeling platform, we have developed a theoretic spatial dynamic model that represents some of the processes of land degradation associated to livestock grazing in dehesa fenced enclosures. Spatial resolution is high since every cell in the model is a square unit area of 1 m2. We paid particular attention to the relationships between soil degradation by compaction (porosity), livestock pressure, rainfall, pasture growth and shrub cover and bare soil generation. The model considers pasture growth as related to soil compaction, measured by the pore space in the top 10 cm soil layer. Annual precipitation is randomly generated following a normal distribution. When annual precipitation and pore space increase, also does pasture growth. Besides, there is a feedback between pasture growth and pore space, given that pasture roots increases soil porosity. The cell utility for livestock function has been defined as an exponential function of the distance of a cell to watering points and the amount of pasture present in it. The closer the cell to a pond and the higher the amount of pasture, the higher is cell utility. The latter is modulated by a normal random variable to

  15. Degradation of a xanthene dye by Fe(II)-mediated activation of Oxone process.

    Science.gov (United States)

    Wang, Y R; Chu, W

    2011-02-28

    A powerful oxidation process using sulfate radicals activated by transition metal mediated Oxone process has been evaluated in depth by monitoring the degradation of a xanthene dye Rhodamine B (RhB) in aqueous solution. Ferrous ion was chosen as the transition metal due to its potential catalytic effect and wide availability in dyeing industrial effluent. The effects of parameters including reactant dosing sequence, Fe(II)/Oxone molar ratio and concentration, solution pH, and inorganic salts on the process performance have been investigated. Total RhB removal was obtained within 90 min under an optimal Fe(II)/Oxone molar ratio of 1:1. The RhB degradation was found to be a two-stage kinetics, consisting of a rapid initial decay and followed by a retarded stage. Additionally, experimental results indicated that the presence of certain anions had either a positive or negative effect on the process. The inhibitory effect in the presence of SO(4)(2-) was elucidated by a proposed formula using Nernst equation. Furthermore, dye mineralization in terms of TOC removal indicates that stepwise addition of Fe(II) and Oxone can significantly improve the process performance by about 20%, and the retention time required can be greatly reduced comparing with the conventional one-off dosing method. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Organophosphorus insecticides: Toxic effects and bioanalytical tests for evaluating toxicity during degradation processes

    Directory of Open Access Journals (Sweden)

    Čolović Mirjana B.

    2013-01-01

    Full Text Available Organophosphorus insecticides have been the most applied group of insecticides for the last two decades. Their main toxic effects are related to irreversible inactivation of acetylcholinesterase (AChE. Actually, they covalently bind to serine OH group in the enzyme active site forming phosphorylated enzyme that cannot hydrolyze acetylcholine. Organophosphorus insecticides in the environment undergo the natural degradation pathway including mainly homogeneous and heterogeneous hydrolysis (especially at high pH generating non-inhibiting products. Additionally, thio organophosphates are easily oxidized by naturally present oxidants and UV light, forming more toxic and stable oxons. Thus, oxidative degradation procedures, generally referred as advanced oxidation processes (AOP, have been applied for their efficient removal from contaminated waters. The most applied bioassays to monitor the organophosphate toxicity i.e. the detoxification degree during AOP are Vibrio fischeri and AChE bioassays. Vibrio fischeri toxicity test exploits bioluminescence as the measure of luciferase activity of this marine bacterium, whereas AChE bioassay is based on AChE activity inhibition. Both bioanalytical techniques are rapid (several minutes, simple, sensitive and reproducible. Vibrio fischeri test seems to be a versatile indicator of toxic compounds generated in AOP for organophosphorus insecticides degradation. However, detection of neurotoxic AChE inhibitors, which can be formed in AOP of some organophosphates, requires AChE bioassays. Therefore, AChE toxicity test is more appropriate for monitoring the degradation processes of thio organophosphates, because more toxic oxo organophosphates might be formed and overlooked by Vibrio fischeri bioluminescence inhibition. In addition, during organophosphates removal by AOP, compounds with strong genotoxic potential may be formed, which cannot be detected by standard toxicity tests. For this reason, determination of

  17. Combined process of electrocoagulation and photocatalytic degradation for the treatment of olive washing wastewater.

    Science.gov (United States)

    Ates, Hasan; Dizge, Nadir; Yatmaz, H Cengiz

    2017-01-01

    In this study, an electrocoagulation reactor (ECR) and photocatalytic reactor (PCR) were tested to understand the performance of combined electrocoagulation and photocatalytic-degradation of olive washing wastewater (OWW). The effects of initial pH (6.0, 6.9, 8.0, 9.0), applied voltage (10.0, 12.5, 15.0 V), and operating time (30, 60, 90, 120 min) were investigated in the electrocoagulation reactor when aluminum electrodes were used as both anode and cathode. The pH, conductivity, color, chemical oxygen demand (COD), and phenol were measured versus time to determine the efficiency of the ECR and PCR process. It was observed that electrocoagulation as a single treatment process supplied the COD removal of 62.5%, color removal of 98.1%, and total phenol removal of 87% at optimum conditions as pH 6.9, applied voltage of 12.5 V, and operating time of 120 min. Moreover, final pH and conductivity were 7.7 and 980 μS/cm, respectively. On the other hand, the effect of semiconductor catalyst type (TiO 2 and ZnO) and loading (1, 2, 3 g/L) were tested using PCR as a stand-alone technique. It was found that photocatalytic degradation as a single treatment process when using 1 g/L ZnO achieved the COD removal of 46%, color removal of 99% with a total phenol removal of 41% at optimum conditions. Final pH and conductivity were 6.2 and 915 μS/cm, respectively. Among semiconductor catalysts, TiO 2 and ZnO performed identical efficiencies for both COD and total phenol removal. Moreover, combination in which electrochemical degradation was employed as a pre-treatment to the photocatalytic degradation process obtained high COD removal of 88% and total phenol, as well as color removal of 100% for the OWW. The electrochemical treatment alone was not effective, but in combination with the photocatalytic process, led to a high-quality effluent. Finally, sludge collected from the electrocoagulation process was characterized by attenuated total reflection Fourier transform infrared and X

  18. THE IMPORTANCE OF INNOVATION IN THE PERFORMANCE OF IPO PROCESSES THAT OCCURRED IN BRAZIL DURING THE LAST DECADE

    Directory of Open Access Journals (Sweden)

    Murilo Sampaio

    2012-01-01

    Full Text Available Innovation is a challenge sought by all economically developed societies. National systems articulate public and private resources so as to shape a more innovative society, capable of ideating and promoting processes, products and services with increasing levels of differentiation before those existing. The search for innovation and the creation of competitive advantages is even greater in the corporate environment, a microeconomic locus where innovation can be measured by efforts and results obtained. Likewise, the number of companies that seek to open themselves to the capital market with views to accumulating resources so as to sustain their strategic growth plans, increases. During the last decade, 245 companies opened their capital in Brazil but only 40% of these went to São Paulo´s Stock Exchange Market (Bovespa negotiate their shares. Upon making its Initial Public Offering (IPO the company has to expose to the stock exchange market its true situation in several areas which are ruled by the Securities and Exchange Commission (CVM. They produce extensive documentation in the form of a robust prospect that is made available to any potential investor. The prospect is known at the capital market as the source that portrays the largest amount of information concerning the company that announced their IPO. It is a legal document but, at the same time, one that in highlight contains, all the attributes and differentials that the company expects the market to evaluate. Thus, by means of secondary sources, all ground on the prospects of IPOs that took place, research was conducted to acknowledge the level of innovation each company presented at the time of their IPO and, at the same time, to measure the performance of the value of stocks that the respective IPO obtained. Subsequently a set of structured qualitative interviews posing to evaluate the results of the quantitative research, was conducted. The quantitative analysis of data collected

  19. Performance of Fluidized bed Fenton process in Degrading Acid Blue 113

    Science.gov (United States)

    Bello, M. M.; Raman, A. A.

    2017-06-01

    The performance of a fluidized bed Fenton process in degrading Acid Blue 113 (AB 113) was investigated. Fluidized bed Fenton process is a modification of conventional Fenton oxidation, aimed at reducing sludge generation and improving process performance. Response surface methodology was used to study the effects of operational parameter on the color removal from the dye. Dimensionless factors, Dye/Fe2+, H2O2/Fe2+ and pH were used as the independent variables in Box-Behnken Design (BDD). Reduced quadratic model was developed to predict the color removal. The process could remove up to 99 % of the initial color. The most significant factor for color removal was found to be Dye/Fe2+, followed by H2O2/Fe2+. Unlike conventional Fenton, the initial pH of the solution does not have a significant effect on the color removal.

  20. Degradation rates in thermophilic sludge processing - the liquid and the solid way

    Energy Technology Data Exchange (ETDEWEB)

    Mihaltz, P.; Kovacs, R.; Csikor, Zs.; Dahab, M.F.

    2003-07-01

    Two promising and well known techniques for sludge stabilization and pathogen destruction, the composting and autothermal thermophilic aerobic digestion (ATAD, often referred to as ''liquid composting'') have not yet undergone a comparative parallel study. This comparison is presented in this paper to identify - sometimes unusually (e.g. up to 30 mg O{sub 2} /gVS h) high - degradation rates, their main influencing parameters. For the ATAD we developed a well fitting modified two-substrate kinetic model quantitatively describing this process feature too - the clear signs of two substrate degradation also appears in most own and literature composting records. However compost process modelling needs as a prerequisite the clarification of the controlling transport mechanisms. Experimental conclusions suggest the dual role of local VS limitation closely connected with, but being behind the strong observed oxygen limitation, what is proposed for the explanation of composting process rates - essentially based on specific surface area controlled transport phenomena, justifying efforts to conduct the process at lower (<20 to 25%) moisture content and higher (>1000 1/m) specific surface area levels. (author)

  1. Optimal Constant-Stress Accelerated Degradation Test Plans Using Nonlinear Generalized Wiener Process

    Directory of Open Access Journals (Sweden)

    Zhen Chen

    2016-01-01

    Full Text Available Accelerated degradation test (ADT has been widely used to assess highly reliable products’ lifetime. To conduct an ADT, an appropriate degradation model and test plan should be determined in advance. Although many historical studies have proposed quite a few models, there is still room for improvement. Hence we propose a Nonlinear Generalized Wiener Process (NGWP model with consideration of the effects of stress level, product-to-product variability, and measurement errors for a higher estimation accuracy and a wider range of use. Then under the constraints of sample size, test duration, and test cost, the plans of constant-stress ADT (CSADT with multiple stress levels based on the NGWP are designed by minimizing the asymptotic variance of the reliability estimation of the products under normal operation conditions. An optimization algorithm is developed to determine the optimal stress levels, the number of units allocated to each level, inspection frequency, and measurement times simultaneously. In addition, a comparison based on degradation data of LEDs is made to show better goodness-of-fit of the NGWP than that of other models. Finally, optimal two-level and three-level CSADT plans under various constraints and a detailed sensitivity analysis are demonstrated through examples in this paper.

  2. Modelling of processes occurring in deep geological repository - development of new modules in the GoldSim environment

    International Nuclear Information System (INIS)

    Vopalka, D.; Lukin, D.; Vokal, A.

    2006-01-01

    Three new modules were prepared in the environment of the GoldSim environment (using its Transport Module). The source term module includes radioactive decay and ingrowth in the canister, first order degradation of fuel matrix, solubility limitation of the concentration of the studied nuclides, and diffusive migration through the surrounding bentonite layer controlled by the output boundary condition formulated with respect to the rate of water flow in the rock. The module was successfully compared with results of similar codes (MIVCYL and Pagoda) and possibilities of the module were extended by a more realistic model of matrix degradation. A better quantification of the role of radionuclide sorption on the bentonite surface was enabled by a module that included non-linear form of the interaction isotherm. Using this module both the influence of the shape of sorption isotherm on the values of diffusion coefficients and the limits of K d -approach that dominates in most codes used in performance assessment studies was discussed. The third of the GoldSim modules presented has been worked out for the description of corrosion of canisters made of carbon steel and for the transport of corrosion products in the near-field region. This module evaluates balance equations between the dissolving species and species transported by diffusion and/or advection from the surface of a solid material. The model also includes transport of iron directly to a fracture in the surrounding rock or into a layer of granite host rock without fractures, and takes into account the reduction of the actual corrosion rate of the canister by growth of the corrosion layer thickness

  3. Application of the Fenton's process in a bubble column reactor for hydroquinone degradation.

    Science.gov (United States)

    Lima, Vanessa N; Rodrigues, Carmen S D; Madeira, Luis M

    2017-11-27

    The aim of this study was to assess the degradation and mineralization of hydroquinone (HQ) by the Fenton's process in a bubble column reactor (BCR). The effect of the main operating variables, namely, air flow rate, effluent volume, hydrogen peroxide (H 2 O 2 ) concentration, catalyst (Fe 2+ ) dose, initial pH, and temperature, were assessed. For all air flow rates tested, no concentration gradients along the column were noticed, evidencing that a good mixing was reached in the BCR. For the best conditions tested ([H 2 O 2 ] = 500 mg/L, [Fe 2+ ] = 45 mg/L, T = 24 °C, Q air  = 2.5 mL/min, pH = 3.0, and V = 5 L), complete HQ degradation was reached, with ~ 39% of total organic carbon (TOC) removal, and an efficiency of the oxidant use-η H2O2 -of 0.39 (ratio between TOC removed per H 2 O 2 consumed normalized by the theoretical stoichiometric value); moreover, a non-toxic effluent was generated. Under these conditions, the intermediates and final oxidation compounds identified and quantified were a few carboxylic acids, namely, maleic, pyruvic, and oxalic. As a strategy to improve the TOC removal, a gradual dosage of the optimal H 2 O 2 concentration was implemented, being obtained ~ 55% of mineralization (with complete HQ degradation). Finally, the matrix effect was evaluated, for which a real wastewater was spiked with 100 mg/L of HQ; no reduction in terms of HQ degradation and mineralization was observed compared to the solution in distilled water.

  4. Documentation Protocols to Generate Risk Indicators Regarding Degradation Processes for Cultural Heritage Risk Evaluation

    Science.gov (United States)

    Kioussi, A.; Karoglou, M.; Bakolas, A.; Labropoulos, K.; Moropoulou, A.

    2013-07-01

    Sustainable maintenance and preservation of cultural heritage assets depends highly on its resilience to external or internal alterations and to various hazards. Risk assessment of a heritage asset's can be defined as the identification of all potential hazards affecting it and the evaluation of the asset's vulnerability (building materials and building structure conservation state).Potential hazards for cultural heritage are complex and varying. The risk of decay and damage associated with monuments is not limited to certain long term natural processes, sudden events and human impact (macroscale of the heritage asset) but is also a function of the degradation processes within materials and structural elements due to physical and chemical procedures. Obviously, these factors cover different scales of the problem. The deteriorating processes in materials may be triggered by external influences or caused because of internal chemical and/or physical variations of materials properties and characteristics. Therefore risk evaluation should be dealt in the direction of revealing the specific active decay and damage mechanism both in mesoscale [type of decay and damage] and microscale [decay phenomenon mechanism] level. A prerequisite for risk indicators identification and development is the existence of an organised source of comparable and interoperable data about heritage assets under observation. This unified source of information offers a knowledge based background of the asset's vulnerability through the diagnosis of building materials' and building structure's conservation state, through the identification of all potential hazards affecting these and through mapping of its possible alterations during its entire life-time. In this framework the identification and analysis of risks regarding degradation processes for the development of qualitative and quantitative indicators can be supported by documentation protocols. The data investigated by such protocols help

  5. DOCUMENTATION PROTOCOLS TO GENERATE RISK INDICATORS REGARDING DEGRADATION PROCESSES FOR CULTURAL HERITAGE RISK EVALUATION

    Directory of Open Access Journals (Sweden)

    A. Kioussi

    2013-07-01

    Full Text Available Sustainable maintenance and preservation of cultural heritage assets depends highly on its resilience to external or internal alterations and to various hazards. Risk assessment of a heritage asset's can be defined as the identification of all potential hazards affecting it and the evaluation of the asset's vulnerability (building materials and building structure conservation state.Potential hazards for cultural heritage are complex and varying. The risk of decay and damage associated with monuments is not limited to certain long term natural processes, sudden events and human impact (macroscale of the heritage asset but is also a function of the degradation processes within materials and structural elements due to physical and chemical procedures. Obviously, these factors cover different scales of the problem. The deteriorating processes in materials may be triggered by external influences or caused because of internal chemical and/or physical variations of materials properties and characteristics. Therefore risk evaluation should be dealt in the direction of revealing the specific active decay and damage mechanism both in mesoscale [type of decay and damage] and microscale [decay phenomenon mechanism] level. A prerequisite for risk indicators identification and development is the existence of an organised source of comparable and interoperable data about heritage assets under observation. This unified source of information offers a knowledge based background of the asset's vulnerability through the diagnosis of building materials' and building structure's conservation state, through the identification of all potential hazards affecting these and through mapping of its possible alterations during its entire life-time. In this framework the identification and analysis of risks regarding degradation processes for the development of qualitative and quantitative indicators can be supported by documentation protocols. The data investigated by such

  6. Comparison of Five Advanced Oxidation Processes for Degradation of Pesticide in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Augustine Chioma Affam

    2018-01-01

    Full Text Available The study compared the technical efficiency and economic cost of five advanced oxidation processes (Fenton, UV photo-Fenton, solar photo-Fenton, UV/TiO2/H2O2 and FeGAC/H2O2 for degradation of the pesticides chlorpyrifos cypermethrin and chlorothalonil in aqueous solution. The highest degradation in terms of COD and TOC removals and improvement of the biodegradability (BOD5/COD ratio index (BI were observed to be (i Fenton - 69.03% (COD, 55.61% (TOC, and 0.35 (BI; (ii UV photo-Fenton -78.56% (COD, 63.76% (TOC and 0.38 (BI;  (iii solar photo-Fenton - 74.19% (COD, 58.32% (TOC and 0.36 (BI; (iv UV/TiO2/H2O2 - 53.62% (COD, 21.54% (TOC, and 0.26 (BI; and  (v the most technical efficient and cost effective process was FeGAC/H2O2. At an optimum condition (FeGAC 5 g/L, H2O2 100 mg/L, and reaction time of 60 min at pH 3, the COD and TOC removal efficiency were 96.19 and 85.60%, respectively, and the biodegradation index was 0.40. The degradation rate constant and cost were 0.0246 min-1 and $0.74/kg TOC, respectively. The FeGAC/H2O2 process is the most technically efficient and cost effective for pretreatment of the pesticide wastewater before biological treatment. Copyright © 2018 BCREC Group. All rights reserved Received: 26th July 2017; Revised: 26nd September 2017; Accepted: 27th September 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Affam, A.C., Chaudhuri, M., Kutty, S.R.M. (2018. Comparison of Five Advanced Oxidation Processes for Degradation of Pesticide in Aqueous Solution. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1: 179-186 (doi:10.9767/bcrec.13.1.1394.179-186

  7. Study of herbicide ametryne degradation in HDPE packaging using the advanced oxidation process by ionizing radiation

    International Nuclear Information System (INIS)

    Andrade, Debora Cristina de

    2008-01-01

    This study is part of the project with the objective to evaluate pesticides degradation for decontamination of commercial polymeric packaging of high density polyethylene, HDPE, used in agriculture. The herbicide used to this study was the herbicide ametryne (commercial name, Gesapax 500), due to its great use, mainly on field crops and on corn. Ametryne is commercialized since 1975, and, depending on the pesticide formulation and type of application, residues may be detectable in water, soil and on the surfaces for months or years. In order to evaluate the efficiency of radiation processing on removal the pesticides contamination, HDPE packaging were irradiated using Radiation Dynamics Electron Beam Accelerator with 1,5 MeV energy and 37 kW, in batch system. The samples were irradiated with water, in various absorbed doses. Ametryne was analyzed by gas chromatography (GC Shimadzu 17A), after extraction with hexane/dichloromethane (1:1 v/v) solution. The calibration curve was obtained with a regression coefficient of 0.986, and the relative standard deviation was lower than 10%. The radiation processing yield was evaluated by the rate of ametryne degradation and by the destruction G-value (Gd). The electron beam irradiation processing, showed high efficiency in destroying ametryne in the HDPE packaging when the samples were irradiated in presence of small quantities of water. (author)

  8. Quantitative modelling of the degradation processes of cement grout. Project CEMMOD

    International Nuclear Information System (INIS)

    Grandia, Fidel; Galindez, Juan-Manuel; Arcos, David; Molinero, Jorge

    2010-05-01

    Grout cement is planned to be used in the sealing of water-conducting fractures in the deep geological storage of spent nuclear fuel waste. The integrity of such cementitious materials should be ensured in a time framework of decades to a hundred of years as mimum. However, their durability must be quantified since grout degradation may jeopardize the stability of other components in the repository due to the potential release of hyperalkaline plumes. The model prediction of the cement alteration has been challenging in the last years mainly due to the difficulty to reproduce the progressive change in composition of the Calcium-Silicate-Hydrate (CSH) compounds as the alteration proceeds. In general, the data obtained from laboratory experiments show a rather similar dependence between the pH of pore water and the Ca-Si ratio of the CSH phases. The Ca-Si ratio decreases as the CSH is progressively replaced by Si-enriched phases. An elegant and reasonable approach is the use of solid solution models even keeping in mind that CSH phases are not crystalline solids but gels. An additional obstacle is the uncertainty in the initial composition of the grout to be considered in the calculations because only the recipe of low-pH clinker is commonly provided by the manufacturer. The hydration process leads to the formation of new phases and, importantly, creates porosity. A number of solid solution models have been reported in literature. Most of them assumed a strong non-ideal binary solid solution series to account for the observed changes in the Ca-Si ratios in CSH. However, it results very difficult to reproduce the degradation of the CSH in the whole Ca-Si range of compositions (commonly Ca/Si=0.5-2.5) by considering only two end-members and fixed nonideality parameters. Models with multiple non-ideal end-members with interaction parameters as a function of the solid composition can solve the problem but these can not be managed in the existing codes of reactive

  9. Holistic processing for other-race faces in chinese participants occurs for upright but not inverted faces.

    Science.gov (United States)

    Crookes, Kate; Favelle, Simone; Hayward, William G

    2013-01-01

    Recent evidence suggests stronger holistic processing for own-race faces may underlie the own-race advantage in face memory. In previous studies Caucasian participants have demonstrated larger holistic processing effects for Caucasian over Asian faces. However, Asian participants have consistently shown similar sized effects for both Asian and Caucasian faces. We investigated two proposed explanations for the holistic processing of other-race faces by Asian participants: (1) greater other-race exposure, (2) a general global processing bias. Holistic processing was tested using the part-whole task. Participants were living in predominantly own-race environments and other-race contact was evaluated. Despite reporting significantly greater contact with own-race than other-race people, Chinese participants displayed strong holistic processing for both Asian and Caucasian upright faces. In addition, Chinese participants showed no evidence of holistic processing for inverted faces arguing against a general global processing bias explanation. Caucasian participants, in line with previous studies, displayed stronger holistic processing for Caucasian than Asian upright faces. For inverted faces there were no race-of-face differences. These results are used to suggest that Asians may make more general use of face-specific mechanisms than Caucasians.

  10. MODIS Time Series to Detect Anthropogenic Interventions and Degradation Processes in Tropical Pasture

    Directory of Open Access Journals (Sweden)

    Daniel Alves Aguiar

    2017-01-01

    Full Text Available The unavoidable diet change in emerging countries, projected for the coming years, will significantly increase the global consumption of animal protein. It is expected that Brazilian livestock production, responsible for close to 15% of global production, be prepared to answer to the increasing demand of beef. Consequently, the evaluation of pasture quality at regional scale is important to inform public policies towards a rational land use strategy directed to improve livestock productivity in the country. Our hypothesis is that MODIS images can be used to evaluate the processes of degradation, restoration and renovation of tropical pastures. To test this hypothesis, two field campaigns were performed covering a route of approximately 40,000 km through nine Brazilian states. To characterize the sampled pastures, biophysical parameters were measured and observations about the pastures, the adopted management and the landscape were collected. Each sampled pasture was evaluated using a time series of MODIS EVI2 images from 2000–2012, according to a new protocol based on seven phenological metrics, 14 Boolean criteria and two numerical criteria. The theoretical basis of this protocol was derived from interviews with producers and livestock experts during a third field campaign. The analysis of the MODIS EVI2 time series provided valuable historical information on the type of intervention and on the biological degradation process of the sampled pastures. Of the 782 pastures sampled, 26.6% experienced some type of intervention, 19.1% were under biological degradation, and 54.3% presented neither intervention nor trend of biomass decrease during the period analyzed.

  11. Degradation of endogenous and exogenous genes of genetically modified rice with Cry1Ab during food processing.

    Science.gov (United States)

    Zhang, Wei; Xing, Fuguo; Selvaraj, Jonathan Nimal; Liu, Yang

    2014-05-01

    In order to assess the degradation of endogenous and exogenous genes during food processing, genetically modified rice with Cry1Ab was used as raw material to produce 4 processed foods: steamed rice, rice noodles, rice crackers, and sweet rice wine. The results showed various processing procedures caused different degrees of degradation of both endogenous and exogenous genes. During the processing of steamed rice and rice noodles, the procedures were so mild that only genes larger than 1500 bp were degraded, and no degradation of NOS terminator and Hpt gene was detected. For rice crackers, frying was the most severe procedure, followed by microwaving, baking, boiling, 1st drying, and 2nd drying. For sweet rice wine, fermentation had more impact on degradation of genes than the other processing procedures. All procedures in this study did not lead to degradation of genes to below 200 bp, except for NOS terminator. In the case of stability of the genes studied during processing of rice crackers and sweet rice wine, SPS gene was the most, followed by the Cry1Ab gene, Hpt gene, Pubi promoter, and NOS terminator. In our study, we gained some information about the degradation of endogenous and exogenous genes during 4 foods processing, compared the different stabilities between endogenous and exogenous genes, and analyzed different effects of procedure on degradation of genes. In addition, the fragments of endogenous and exogenous genes about 200 bp could be detected in final products, except NOS terminator. As a result, we provided some base information about risk assessment of genetically modified (GM) food and appropriate length of fragment to detect GM component in processed foods. © 2014 Institute of Food Technologists®

  12. Incidence, species and antimicrobial resistance of naturally occurring Campylobacter isolates from quail carcasses sampled in a commercial processing facility

    Science.gov (United States)

    Most of the published information about the presence of Campylobacter on processed poultry is from studies with chickens and turkeys; therefore there is a paucity of published material about the presence of Campylobacter on commercially processed quail (Coturnix coturnix). The objective of this stud...

  13. Noise Equally Degrades Central Auditory Processing in 2- and 4-Year-Old Children.

    Science.gov (United States)

    Niemitalo-Haapola, Elina; Haapala, Sini; Kujala, Teija; Raappana, Antti; Kujala, Tiia; Jansson-Verkasalo, Eira

    2017-08-16

    The aim of this study was to investigate developmental and noise-induced changes in central auditory processing indexed by event-related potentials in typically developing children. P1, N2, and N4 responses as well as mismatch negativities (MMNs) were recorded for standard syllables and consonants, frequency, intensity, vowel, and vowel duration changes in silent and noisy conditions in the same 14 children at the ages of 2 and 4 years. The P1 and N2 latencies decreased and the N2, N4, and MMN amplitudes increased with development of the children. The amplitude changes were strongest at frontal electrodes. At both ages, background noise decreased the P1 amplitude, increased the N2 amplitude, and shortened the N4 latency. The noise-induced amplitude changes of P1, N2, and N4 were strongest frontally. Furthermore, background noise degraded the MMN. At both ages, MMN was significantly elicited only by the consonant change, and at the age of 4 years, also by the vowel duration change during noise. Developmental changes indexing maturation of central auditory processing were found from every response studied. Noise degraded sound encoding and echoic memory and impaired auditory discrimination at both ages. The older children were as vulnerable to the impact of noise as the younger children. https://doi.org/10.23641/asha.5233939.

  14. Efficient peroxydisulfate activation process not relying on sulfate radical generation for water pollutant degradation.

    Science.gov (United States)

    Zhang, Tao; Chen, Yin; Wang, Yuru; Le Roux, Julien; Yang, Yang; Croué, Jean-Philippe

    2014-05-20

    Peroxydisulfate (PDS) is an appealing oxidant for contaminated groundwater and toxic industrial wastewaters. Activation of PDS is necessary for application because of its low reactivity. Present activation processes always generate sulfate radicals as actual oxidants which unselectively oxidize organics and halide anions reducing oxidation capacity of PDS and producing toxic halogenated products. Here we report that copper oxide (CuO) can efficiently activate PDS under mild conditions without producing sulfate radicals. The PDS/CuO coupled process is most efficient at neutral pH for decomposing a model compound, 2,4-dichlorophenol (2,4-DCP). In a continuous-flow reaction with an empty-bed contact time of 0.55 min, over 90% of 2,4-DCP (initially 20 μM) and 90% of adsorbable organic chlorine (AOCl) can be removed at the PDS/2,4-DCP molar ratio of 1 and 4, respectively. Based on kinetic study and surface characterization, PDS is proposed to be first activated by CuO through outer-sphere interaction, the rate-limiting step, followed by a rapid reaction with 2,4-DCP present in the solution. In the presence of ubiquitous chloride ions in groundwater/industrial wastewater, the PDS/CuO oxidation shows significant advantages over sulfate radical oxidation by achieving much higher 2,4-DCP degradation capacity and avoiding the formation of highly chlorinated degradation products. This work provides a new way of PDS activation for contaminant removal.

  15. Application of controlled radiation-induced degradation in polymers: less exploited aspect of radiation processing of polymers

    International Nuclear Information System (INIS)

    Haji Saeid, M.; Guven, O.

    2007-01-01

    Industrial use of ionizing radiation treatment has been most successful in applications related to polymeric materials. The polymer, plastics and rubber industries have benefited from the unique advantages of ionizing radiation since its inception as an industrial tool to modify their properties and manufacture novel materials with value addition to the end product. The established and emerging applications of electron beam processing of polymers are based on the well known ultimate effects of ionizing radiation on polymers namely, crosslinking, curing, grafting and chain scissioning. Radiation-induced crosslinking dominates most applications, whereas the chain scissioning effect is much less explored and currently limited to radiation-induced degradation of Teflon, cellulose and polypropylene. The controlling of radiation-induced degradation for achieving a target average molecular weight or distribution has been evaluated for some polysaccharides, biopolymers and waste inner tubes whereas mitigation of the degradative effects of radiation has been analyzed from the point of view of using certain stabilizers, copolymers and annealing at an appropriate temperature. Several new or highly specialized techniques such as positron annihilation lifetime spectroscopy. Rutherford backscattering, elastic recoil detection analysis and solid waste NMR spectroscopy and gas chromatography-mass spectroscopy have been applied to the study or radiation-induced degradation. New information has been collected on the morphological changes associated with radiation-induced degradation processes, including chain scission, oxidation and free volume alteration. The IAEA coordinated research project (CRP) on Controlling of Degradation Effects in Radiation Processing of Polymers dealt with the role and importance of using ionizing radiation in controlling properties of natural and synthetic polymers through its degradative effect. This paper provides a summary of most important results

  16. Degradation of 2,4-dinitrophenol using a combination of hydrodynamic cavitation, chemical and advanced oxidation processes.

    Science.gov (United States)

    Bagal, Manisha V; Gogate, Parag R

    2013-09-01

    In the present work, degradation of 2,4-dinitrophenol (DNP), a persistent organic contaminant with high toxicity and very low biodegradability has been investigated using combination of hydrodynamic cavitation (HC) and chemical/advanced oxidation. The cavitating conditions have been generated using orifice plate as a cavitating device. Initially, the optimization of basic operating parameters have been done by performing experiments over varying inlet pressure (over the range of 3-6 bar), temperature (30 °C, 35 °C and 40 °C) and solution pH (over the range of 3-11). Subsequently, combined treatment strategies have been investigated for process intensification of the degradation process. The effect of HC combined with chemical oxidation processes such as hydrogen peroxide (HC/H2O2), ferrous activated persulfate (HC/Na2S2O8/FeSO4) and HC coupled with advanced oxidation processes such as conventional Fenton (HC/FeSO4/H2O2), advanced Fenton (HC/Fe/H2O2) and Fenton-like process (HC/CuO/H2O2) on the extent of degradation of DNP have also been investigated at optimized conditions of pH 4, temperature of 35 °C and inlet pressure of 4 bar. Kinetic study revealed that degradation of DNP fitted first order kinetics for all the approaches under investigation. Complete degradation with maximum rate of DNP degradation has been observed for the combined HC/Fenton process. The energy consumption analysis for hydrodynamic cavitation based process has been done on the basis of cavitational yield. Degradation intermediates have also been identified and quantified in the current work. The synergistic index calculated for all the combined processes indicates HC/Fenton process is more feasible than the combination of HC with other Fenton like processes. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. When seeing depends on knowing: adults with Autism Spectrum Conditions show diminished top-down processes in the visual perception of degraded faces but not degraded objects.

    Science.gov (United States)

    Loth, Eva; Gómez, Juan Carlos; Happé, Francesca

    2010-04-01

    Behavioural, neuroimaging and neurophysiological approaches emphasise the active and constructive nature of visual perception, determined not solely by the environmental input, but modulated top-down by prior knowledge. For example, degraded images, which at first appear as meaningless 'blobs', can easily be recognized as, say, a face, after having seen the same image un-degraded. This conscious perception of the fragmented stimuli relies on top-down priming influences from systems involved in attention and mental imagery on the processing of stimulus attributes, and feature-binding [Dolan, R. J., Fink, G. R., Rolls, E., Booth, M., Holmes, A., Frackowiak, R. S. J., et al. (1997). How the brain learns to see objects and faces in an impoverished context. Nature, 389, 596-599]. In Autism Spectrum Conditions (ASC), face processing abnormalities are well-established, but top-down anomalies in various domains have also been shown. Thus, we tested two alternative hypotheses: (i) that people with ASC show overall reduced top-down modulation in visual perception, or (ii) that top-down anomalies affect specifically the perception of faces. Participants were presented with sets of three consecutive images: degraded images (of faces or objects), corresponding or non-corresponding grey-scale photographs, and the same degraded images again. In a passive viewing sequence we compared gaze times (an index of focal attention) on faces/objects vs. background before and after viewers had seen the undegraded photographs. In an active viewing sequence, we compared how many faces/objects were identified pre- and post-exposure. Behavioural and gaze tracking data showed significantly reduced effects of prior knowledge on the conscious perception of degraded faces, but not objects in the ASC group. Implications for future work on the underlying mechanisms, at the cognitive and neurofunctional levels, are discussed. (c) 2009 Elsevier Ltd. All rights reserved.

  18. Degradation of phthalate in aqueous solution by advanced oxidation process, photo-fenton

    International Nuclear Information System (INIS)

    Trabelsi, S.; Bellakhal, N.; Oturan, N.; Oturan, M.A.

    2009-01-01

    A photochemical method for degradation of persistent organic pollutants present in liquid effluents from the plastic industry and in the leaching described. This method, called P hoto-Fenton i nvolves the generation of radicals hydroxyl coupling between the Fenton reaction and photochemistry, OH radicals. Thus formed react with very high speeds, organic substances pollutants leading to their oxidation to total mineralization. In this study, we applied the process photo-Fenton treatment Plasticizers, Phthalates. For this, optimization of experimental parameters (namely the relationship between the concentrations of hydrogen peroxide and iron concentration catalyst) was performed. Under optimal conditions and determined the kinetics mineralization of phthalic anhydride by OH was studied. The overall results confirm the effectiveness of photo-Fenton process for the decontamination of liquid effluents responsible for persistent organic pollutants (Pop's).

  19. Simulation and prediction of the thuringiensin abiotic degradation processes in aqueous solution by a radius basis function neural network model.

    Science.gov (United States)

    Zhou, Jingwen; Xu, Zhenghong; Chen, Shouwen

    2013-04-01

    The thuringiensin abiotic degradation processes in aqueous solution under different conditions, with a pH range of 5.0-9.0 and a temperature range of 10-40°C, were systematically investigated by an exponential decay model and a radius basis function (RBF) neural network model, respectively. The half-lives of thuringiensin calculated by the exponential decay model ranged from 2.72 d to 16.19 d under the different conditions mentioned above. Furthermore, an RBF model with accuracy of 0.1 and SPREAD value 5 was employed to model the degradation processes. The results showed that the model could simulate and predict the degradation processes well. Both the half-lives and the prediction data showed that thuringiensin was an easily degradable antibiotic, which could be an important factor in the evaluation of its safety. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Periodicity in the autocorrelation function as a mechanism for regularly occurring zero crossings or extreme values of a Gaussian process.

    Science.gov (United States)

    Wilson, Lorna R M; Hopcraft, Keith I

    2017-12-01

    The problem of zero crossings is of great historical prevalence and promises extensive application. The challenge is to establish precisely how the autocorrelation function or power spectrum of a one-dimensional continuous random process determines the density function of the intervals between the zero crossings of that process. This paper investigates the case where periodicities are incorporated into the autocorrelation function of a smooth process. Numerical simulations, and statistics about the number of crossings in a fixed interval, reveal that in this case the zero crossings segue between a random and deterministic point process depending on the relative time scales of the periodic and nonperiodic components of the autocorrelation function. By considering the Laplace transform of the density function, we show that incorporating correlation between successive intervals is essential to obtaining accurate results for the interval variance. The same method enables prediction of the density function tail in some regions, and we suggest approaches for extending this to cover all regions. In an ever-more complex world, the potential applications for this scale of regularity in a random process are far reaching and powerful.

  1. Periodicity in the autocorrelation function as a mechanism for regularly occurring zero crossings or extreme values of a Gaussian process

    Science.gov (United States)

    Wilson, Lorna R. M.; Hopcraft, Keith I.

    2017-12-01

    The problem of zero crossings is of great historical prevalence and promises extensive application. The challenge is to establish precisely how the autocorrelation function or power spectrum of a one-dimensional continuous random process determines the density function of the intervals between the zero crossings of that process. This paper investigates the case where periodicities are incorporated into the autocorrelation function of a smooth process. Numerical simulations, and statistics about the number of crossings in a fixed interval, reveal that in this case the zero crossings segue between a random and deterministic point process depending on the relative time scales of the periodic and nonperiodic components of the autocorrelation function. By considering the Laplace transform of the density function, we show that incorporating correlation between successive intervals is essential to obtaining accurate results for the interval variance. The same method enables prediction of the density function tail in some regions, and we suggest approaches for extending this to cover all regions. In an ever-more complex world, the potential applications for this scale of regularity in a random process are far reaching and powerful.

  2. INVIVO DEGRADATION OF PROCESSED DERMAL SHEEP COLLAGEN EVALUATED WITH TRANSMISSION ELECTRON-MICROSCOPY

    NARCIS (Netherlands)

    VANWACHEM, PB; VANLUYN, MJA; NIEUWENHUIS, P; KOERTEN, HK; DAMINK, LO; TENHOOPEN, H; FEIJEN, J

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  3. In vivo degradation of processed dermal sheep collagen evaluated with transmission electron microscopy

    NARCIS (Netherlands)

    van Wachem, P.B.; van Luyn, M.J.A.; Nieuwenhuis, P.; Koerten, H.K.; Olde damink, L.H.H.; Olde-Damink, L.; ten Hoopen, Hermina W.M.; Feijen, Jan

    1991-01-01

    The in vivo degradation of hexamethylenediisocyanate-tanned dermal sheep collagen was studied with transmission electron microscopy. Discs of hexamethylenediisocyanate-tanned dermal sheep collagen were subcutaneously implanted in rats. Both an intra- and an extracellular route of degradation could

  4. Enhanced degradation of paracetamol by UV-C supported photo-Fenton process over Fenton oxidation.

    Science.gov (United States)

    Manu, B; Mahamood, S

    2011-01-01

    For the treatment of paracetamol in water, the UV-C Fenton oxidation process and classic Fenton oxidation have been found to be the most effective. Paracetamol reduction and chemical oxygen demand (COD) removal are measured as the objective functions to be maximized. The experimental conditions of the degradation of paracetamol are optimized by the Fenton process. Influent pH 3, initial H(2)O(2) dosage 60 mg/L, [H(2)O(2)]/[Fe(2+)] ratio 60 : 1 are the optimum conditions observed for 20 mg/L initial paracetamol concentration. At the optimum conditions, for 20 mg/L of initial paracetamol concentration, 82% paracetamol reduction and 68% COD removal by Fenton oxidation, and 91% paracetamol reduction and 82% COD removal by UV-C Fenton process are observed in a 120 min reaction time. By HPLC analysis, 100% removal of paracetamol is observed at the above optimum conditions for the Fenton process in 240 min and for the UV-C photo-Fenton process in 120 min. The methods are effective and they may be used in the paracetamol industry.

  5. A highly energy-efficient flow-through electro-Fenton process for organic pollutants degradation

    International Nuclear Information System (INIS)

    Ma, Liang; Zhou, Minghua; Ren, Gengbo; Yang, Weilu; Liang, Liang

    2016-01-01

    Highlights: • A highly energy-efficient flow-through electro-Fenton reactor was designed. • It had high H 2 O 2 yield and low energy consumption for organic pollutants degradation. • The effect of operational parameters was optimized and possible process mechanism was studied. • The novel system performed wide practicability and potential for organic pollutants degradation. - Abstract: A highly energy-efficient flow-through Electro-Fenton (E-Fenton) reactor for oxidation of methylene blue (MB) from aqueous solution was designed using a perforated DSA as anode and the graphite felt modified by carbon black and polytetrafluoroethylene (PTFE) as cathode for the in situ generation of H 2 O 2 . The modified cathode had a high H 2 O 2 production with low energy consumption, which was characterized by scanning electron microscopy (SEM), nitrogen adsorption-desorption study and contact angle. The flow-through E-Fenton system was compared to the flow-by and regular one, and confirmed to be best on MB removal and TOC degradation. The operational parameters such as current density, pH, Fe 2+ concentration and flow rate were optimized. The MB and TOC removal efficiency of the effluents could keep above 90% and 50%, respectively, and the energy consumption was 23.0 kWh/kgTOC at the current density of 50 mA, pH 3, 0.3 mM Fe 2+ , and the flow rate of 7 mL/min. ·OH was proved to be the main oxidizing species in this system. After 5 times operation, the system, especially cathode, still showed good stability. Five more organic pollutants including orange II (OG), tartrazine, acetylsalicylic acid (ASA), tetracycline (TC) and 2,4-dichlorophen (2,4-DCP) were investigated and the electric energy consumption (EEC) was compared with literatures. All results demonstrated that this flow-through E-Fenton system was energy-efficient and potential for degradation of organic pollutants.

  6. The importance of Soil Science to understand and remediate Land Degradation and Desertification processes

    Science.gov (United States)

    Bouma, Johan; Keesstra, Saskia; Cerdà, Artemi

    2017-04-01

    Documentation is abundantly available to demonstrate the devastating effect of Land degradation and desertification on sustainable development in many countries. This present a major barrier to achieving the UN Sustainable Development Goals by 2030, as agreed upon at the General Assembly of the UN in September 2015. Research has certainly been successful in reversing these two processes in many case studies but persistant problems remain not only in developing countries but also in developed countries where, for example, soil compaction and loss of soil organic matter due to the industrialization of agriculture, result in a structural decline of agricultural productivity and environmental quality. The problems are quite complex because not only technical matters play a role but also, and often quite prominantly, socio-economic factors. What turn out to be successful remediation procedures at a given location or region, based on the characterization of underlying soil processes, will most likely not work in other regions inhibiting the extrapolation of local research results to areas elsewhere. One important reason for location specificity of research is the variation of soil properties in combination with the location of soils in a given landscape which governs its water, energy and nutrient dynamics, also considering the climate. Different soils are characterized by different natural riks for degradation and , in arid regions, deserticification and their particular remediation potential differs widely as well. Such risks can sometimes be overcome by innovative soil management and knowing the soil type, the climate and landscape processes, extrapolation of such types of innovative management to comparable soils and landscapes elsewhere may be feasible and effective , provided that socio-economic conditions allow the required risk-reducing measures to be realized in practice. More cooperation between soil scientists and physical geographers, familiar with landscape

  7. Drug-releasing shape-memory polymers - the role of morphology, processing effects, and matrix degradation.

    Science.gov (United States)

    Wischke, Christian; Behl, Marc; Lendlein, Andreas

    2013-09-01

    Shape-memory polymers (SMPs) have gained interest for temporary drug-release systems that should be anchored in the body by self-sufficient active movements of the polymeric matrix. Based on the so far published scientific literature, this review highlights three aspects that require particular attention when combining SMPs with drug molecules: i) the defined polymer morphology as required for the shape-memory function, ii) the strong effects that processing conditions such as drug-loading methodologies can have on the drug-release pattern from SMPs, and iii) the independent control of drug release and degradation by their timely separation. The combination of SMPs with a drug-release functionality leads to multifunctional carriers that are an interesting technology for pharmaceutical sciences and can be further expanded by new materials such as thermoplastic SMPs or temperature-memory polymers. Experimental studies should include relevant molecules as (model) drugs and provide a thermomechanical characterization also in an aqueous environment, report on the potential effect of drug type and loading levels on the shape-memory functionality, and explore the potential correlation of polymer degradation and drug release.

  8. Degradation of cytotoxic agent in soap and detergent wastewater by advanced oxidation processes

    International Nuclear Information System (INIS)

    Iqbal, M.; Bhatti, I.A.; Nisar, J.

    2017-01-01

    Wastewater from soap and detergent industries is a source of high pollution and contamination for water sheds. In present investigation, cytotoxic profiling was documented from Faisalabad, Sargodha and Gujranwala cities, Pakistan, followed by advanced oxidation processes (AOPs) treatments (UV and gamma radiation). The cytotoxicity was evaluated by Allium cepa, haemolytic and brine shrimp bioassays. Independent variables such as gamma radiation absorbed dose, H2O2, TiO2 concentrations, reaction time, pH and shaking speed were optimized using statistical techniques. The raw soap and detergent wastewater showed cytotoxicity up to high extent. At optimized conditions, > 94% degradation was achieved both in case of UV (exposure time 100 min, TiO2 concentration 5.93 g/L, H2O2 4.39%, pH 6.50 and shaking speed 110 rpm) and gamma radiation (12.69 kGy absorbed dose in the presence of 4.65% H2O2) treated samples and water quality parameters (WQP) also improved significantly. The cytotoxicity reduced sharply as a result of AOPs treatment at optimized conditions. From the results, it is evident that AOPs under investigation could be used for the degradation and cytotoxicity reduction of soap and detergent wastewater. (author)

  9. ssDNA degradation along capillary electrophoresis process using a Tris buffer.

    Science.gov (United States)

    Ric, Audrey; Ong-Meang, Varravaddheay; Poinsot, Verena; Martins-Froment, Nathalie; Chauvet, Fabien; Boutonnet, Audrey; Ginot, Frédéric; Ecochard, Vincent; Paquereau, Laurent; Couderc, François

    2017-06-01

    Tris-Acetate buffer is currently used in the selection and the characterization of ssDNA by capillary electrophoresis (CE). By applying high voltage, the migration of ionic species into the capillary generates a current that induces water electrolysis. This phenomenon is followed by the modification of the pH and the production of Tris derivatives. By injecting ten times by capillary electrophoresis ssDNA (50 nM), the whole oligonucleotide was degraded. In this paper, we will show that the Tris buffer in the running vials is modified along the electrophoretic process by electrochemical reactions. We also observed that the composition of the metal ions changes in the running buffer vials. This phenomenon, never described in CE, is important for fluorescent ssDNA analysis using Tris buffer. The oligonucleotides are degraded by electrochemically synthesized species (present in the running Tris vials) until it disappears, even if the separation buffer in the capillary is clean. To address these issues, we propose to use a sodium phosphate buffer that we demonstrate to be electrochemically inactive. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Comparing population patterns to processes: abundance and survival of a forest salamander following habitat degradation.

    Directory of Open Access Journals (Sweden)

    Clint R V Otto

    Full Text Available Habitat degradation resulting from anthropogenic activities poses immediate and prolonged threats to biodiversity, particularly among declining amphibians. Many studies infer amphibian response to habitat degradation by correlating patterns in species occupancy or abundance with environmental effects, often without regard to the demographic processes underlying these patterns. We evaluated how retention of vertical green trees (CANOPY and coarse woody debris (CWD influenced terrestrial salamander abundance and apparent survival in recently clearcut forests. Estimated abundance of unmarked salamanders was positively related to CANOPY (β Canopy  = 0.21 (0.02-1.19; 95% CI, but not CWD (β CWD  = 0.11 (-0.13-0.35 within 3,600 m2 sites, whereas estimated abundance of unmarked salamanders was not related to CANOPY (β Canopy  = -0.01 (-0.21-0.18 or CWD (β CWD  = -0.02 (-0.23-0.19 for 9 m2 enclosures. In contrast, apparent survival of marked salamanders within our enclosures over 1 month was positively influenced by both CANOPY and CWD retention (β Canopy  = 0.73 (0.27-1.19; 95% CI and β CWD  = 1.01 (0.53-1.50. Our results indicate that environmental correlates to abundance are scale dependent reflecting habitat selection processes and organism movements after a habitat disturbance event. Our study also provides a cautionary example of how scientific inference is conditional on the response variable(s, and scale(s of measure chosen by the investigator, which can have important implications for species conservation and management. Our research highlights the need for joint evaluation of population state variables, such as abundance, and population-level process, such as survival, when assessing anthropogenic impacts on forest biodiversity.

  11. Study on the behavior of naturally occurring radioactivity originated from heavy minerals in weathering process of granite

    International Nuclear Information System (INIS)

    Nakano, M.; Nakashima, Y.

    1993-01-01

    Mass fraction of biotite and of heavy minerals originally in granite rocks at Naegi granite area are 3% and 1 x 10 -4 %, respectively. Though their values are very small, specific activities of 238 U is 1.3 Bq/g and 80 Bq/g, respectively. Their values are much higher than that of gross granite (0.1 Bq/g). Therefore, they play important roles in the weathering process. Authors separated biotite and heavy minerals from less-weathered and weathered (outcrop, plastic materials) granite samples by using heavy liquid, and determined each specific activities and activity ratios. Furthermore, the surface of heavy minerals were washed in 6 N HCl for 20 minutes. And lost fraction of activity in the heavy minerals was determined. The result suggested that activity around heavy mineral's surface was removed into surroundings or external environment through weathering process. (5 figs.)

  12. Identification of key processes ruling environmental behaviour of naturally occurring radionuclides on example of Polish Observatory Site

    Energy Technology Data Exchange (ETDEWEB)

    Michalik, Boguslaw [Silesian Centre for Environmental Radioactivity, Glowny Instytut Gornictwa, Plac Gwarkow 1, 40-166 Katowice (Poland)

    2014-07-01

    Developing a sufficient understanding of environmental processes and exposure pathways that permit observations to be explained and robust predictions to be made over spatial and temporal scales is a clear challenge that radioecology needs to address. This scientific challenge has been developed as a separate section of the Strategic Research Agenda (SRA) a document produced by the STAR Network of Excellence in Radioecology that outlines a suggested prioritisation of research topics in radioecology. Reality is that in order to bring the SRA to fruition, besides considerable resources and time, an available proving ground is required. The sole sources of such data are areas affected by nuclear accidents but the conditions provided do not follow requirements for scientific experiment. On the other hand, it is hard to imagine anyone deliberately releasing substantial amount of radioactivity into environment in order to observe what would happen- Some of coal mines at Upper Silesia Coal Basin have discharged radium reach brines continuously for many years. The total amount of radium released to inland water is quite well known and varies with time or exploitation conditions. This phenomenon has been observed for more than 30 years and many contaminated sites being in different state were identified. Natural radionuclides (mainly radium isotopes) present in mine water after its release into the environment are subject to different chemical and/or physical processes influencing their final fate. The processes of concern are e.g. precipitation, sedimentation, adsorption, absorption, ion exchange, desorption, leaching, erosion, sequential decay etc. Based on physical and chemical rules, available data and real environmental conditions the key processes that govern radium and its progeny behaviour after discharge with mine water, associated transfers among environmental compartments and resulting exposures of both non-human and humans populations have been identified. The

  13. Angle resolved electron spectroscopy of spontaneous ionization processes occurring in doubly charged ion-surface collisions at grazing incidence

    International Nuclear Information System (INIS)

    Wouters, P.A.A.F.; Emmichoven, P.A.Z. van; Niehaus, A.

    1989-01-01

    The experimental setup used to measure electron spectra at well defined detection angles for grazing incidence doubly charged ion-surface collisions at keV-energies is described. Electron spectra are reported for the rare gas ions colliding with a Cu(110)-surface. The spectra are analyzed in terms of various spontaneous ionization processes using a newly developed model. It is found that double capture followed by atomic auto-ionization on the incoming trajectory and Auger-capture processes in which the first and second hole in the doubly charged projectiles are successively filled are the main processes contributing to the electron spectra. From a comparison of model calculations with measured spectra it is concluded that the metal electrons cannot adapt adiabatically to the sudden changes of the charge state of the projectile in front of the surface. A parameter characterizing the partly diabatic behavior is determined. The variation of spectra upon adsorption of a monolayer of oxygen on the surface is reported and discussed. (author)

  14. On the course of fusion processes occurring in the plasma focus - an investigation by using time-resolved neutron spectroscopy

    International Nuclear Information System (INIS)

    Schmidt, R.

    1987-01-01

    The plasma focus POSEIDON emits up to 2x10 11 neutrons during some 100 ns, if it is operated with deuterium. This very high neutron production cannot be explained by a thermal neutron production mechanism starting out from the measured values of temperature (about 1 KeV) and deuteron density (10 18 cm -3 ). There is no doubt, that there exist strong ''beam-target''-processes of the deuterons, which cause such a high suprathermal neutron production. The neutron emission of the plasma focus POSEIDON appears in two pulses, which are associated to the two main phases of the hot and dense plasma. The first is the pinch or quiescent phase, in which a stable plasma column over 100 or 150 ns exists. The second phase is characterized by turbulence processes and starts with the end of the stable phase with the on-set of the m=0-instabilities and ends with the decay of the plasma. Both phases of neutron production are studied by time-resolved analysis of the neutron anisotropy factor and by time and spatial-resolved measurements of the neutron emission. Hence it follows, that there exist during both phases different non thermal neutron production processes, which are caused by different deuteron acceleration mechanisms. To get information on these deuteron acceleration mechanisms it is appropriate to analyse the neutron spectra of the plasma focus, because the half-width and the shape of the measured spectra are related to the energy and the angular distribution of the accelerated deuterons. (orig./GG) [de

  15. [Determination of sennosides and degraded products in the process of sennoside metabolism by HPLC].

    Science.gov (United States)

    Sun, Yan; Li, Xuetuo; Yu, Xingju

    2004-01-01

    A method for the separation and determination of sennosides A and B and the main composition (sennidins A and B) in degraded products of sennosides by linear gradient high performance liquid chromatography has been developed. Separation conditions were as follows: column, a Spherisorb C18 column (250 mm x 4.6 mm i.d., 10 microm); column temperature, 40 degrees C; detection wavelength, 360 nm; mobile phase A, 1.25% acetic acid aqueous solution; mobile phase B, methanol; linear gradient, 100% A --> (20 min) 100% B. The method is effective, quick, accurate and reproducible. The satisfactory results show that this new method has certain practical values as an approach of real-time analysis in the process of sennoside metabolism.

  16. Research On Degradation Of Silk Fibroin By Combination Of Electron Beam Irradiation And Hydrothermal Processing

    International Nuclear Information System (INIS)

    Nguyen Thi Kim Lan; Dang Van Phu; Le Anh Quoc; Nguyen Quoc Hien

    2014-01-01

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The protein content increased from 0.4617 to 0.6530 mg/mg when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  17. Efficient peroxydisulfate activation process not relying on sulfate radical generation for water pollutant degradation

    KAUST Repository

    Zhang, Tao

    2014-05-20

    Peroxydisulfate (PDS) is an appealing oxidant for contaminated groundwater and toxic industrial wastewaters. Activation of PDS is necessary for application because of its low reactivity. Present activation processes always generate sulfate radicals as actual oxidants which unselectively oxidize organics and halide anions reducing oxidation capacity of PDS and producing toxic halogenated products. Here we report that copper oxide (CuO) can efficiently activate PDS under mild conditions without producing sulfate radicals. The PDS/CuO coupled process is most efficient at neutral pH for decomposing a model compound, 2,4-dichlorophenol (2,4-DCP). In a continuous-flow reaction with an empty-bed contact time of 0.55 min, over 90% of 2,4-DCP (initially 20 μM) and 90% of adsorbable organic chlorine (AOCl) can be removed at the PDS/2,4-DCP molar ratio of 1 and 4, respectively. Based on kinetic study and surface characterization, PDS is proposed to be first activated by CuO through outer-sphere interaction, the rate-limiting step, followed by a rapid reaction with 2,4-DCP present in the solution. In the presence of ubiquitous chloride ions in groundwater/industrial wastewater, the PDS/CuO oxidation shows significant advantages over sulfate radical oxidation by achieving much higher 2,4-DCP degradation capacity and avoiding the formation of highly chlorinated degradation products. This work provides a new way of PDS activation for contaminant removal. © 2014 American Chemical Society.

  18. Application of poultry processing industry waste: a strategy for vegetation growth in degraded soil.

    Science.gov (United States)

    do Nascimento, Carla Danielle Vasconcelos; Pontes Filho, Roberto Albuquerque; Artur, Adriana Guirado; Costa, Mirian Cristina Gomes

    2015-02-01

    The disposal of poultry processing industry waste into the environment without proper care, can cause contamination. Agricultural monitored application is an alternative for disposal, considering its high amount of organic matter and its potential as a soil fertilizer. This study aimed to evaluate the potential of poultry processing industry waste to improve the conditions of a degraded soil from a desertification hotspot, contributing to leguminous tree seedlings growth. The study was carried out under greenhouse conditions in a randomized blocks design and a 4 × 2 factorial scheme with five replicates. The treatments featured four amounts of poultry processing industry waste (D1 = control 0 kg ha(-1); D2 = 1020.41 kg ha(-1); D3 = 2040.82 kg ha(-1); D4 = 4081.63 kg ha(-1)) and two leguminous tree species (Mimosa caesalpiniaefolia Benth and Leucaena leucocephala (Lam.) de Wit). The poultry processing industry waste was composed of poultry blood, grease, excrements and substances from the digestive system. Plant height, biomass production, plant nutrient accumulation and soil organic carbon were measured forty days after waste application. Leguminous tree seedlings growth was increased by waste amounts, especially M. caesalpiniaefolia Benth, with height increment of 29.5 cm for the waste amount of 1625 kg ha(-1), and L. leucocephala (Lam.) de Wit, with maximum height increment of 20 cm for the waste amount of 3814.3 kg ha(-1). M. caesalpiniaefolia Benth had greater initial growth, as well as greater biomass and nutrient accumulation compared with L. leucocephala (Lam.) de Wit. However, belowground biomass was similar between the evaluated species, resulting in higher root/shoot ratio for L. leucocephala (Lam.) de Wit. Soil organic carbon did not show significant response to waste amounts, but it did to leguminous tree seedlings growth, especially L. leucocephala (Lam.) de Wit. Poultry processing industry waste contributes to leguminous tree seedlings growth

  19. Degradation kinetics of reactive dye by UV/H2O2/US process under continuous mode operation.

    Science.gov (United States)

    Fung, P C; Poon, C S; Chu, C W; Tsui, S M

    2001-01-01

    Degradation of a dye, C. I . Reactive Red 120, in dyeing waatewater by the process o UV/H2O2/US was studied with a bench-scale reactor under the continuous mode of operation. The effects of dyeing wastewater flow rate and the feeding rate of an oxidant, H2O2, on the color removal efficiency of the process were investigated. The significance of ultrasonic (US) combined with UV irradiation was also investigated and the performances of the process on color removal were evaluated. The results showed that the decoloration process followed a pseudo first-order kinetic model and the UV light is the most significant factor on dye removal. Besides, at higher flow rates, incomplete color removal was observed due to relatively insufficient irradiation time (low degradation rate). In order to achieve a higher degradation rate, the feeding rate of H2O2 should be increased.

  20. Cotranslocational processing of the protein substrate calmodulin by an AAA+ unfoldase occurs via unfolding and refolding intermediates.

    Science.gov (United States)

    Augustyniak, Rafal; Kay, Lewis E

    2018-05-22

    Protein remodeling by AAA+ enzymes is central for maintaining proteostasis in a living cell. However, a detailed structural description of how this is accomplished at the level of the substrate molecules that are acted upon is lacking. Here, we combine chemical cross-linking and methyl transverse relaxation-optimized NMR spectroscopy to study, at atomic resolution, the stepwise unfolding and subsequent refolding of the two-domain substrate calmodulin by the VAT AAA+ unfoldase from Thermoplasma acidophilum By engineering intermolecular disulphide bridges between the substrate and VAT we trap the substrate at different stages of translocation, allowing structural studies throughout the translocation process. Our results show that VAT initiates substrate translocation by pulling on intrinsically unstructured N or C termini of substrate molecules without showing specificity for a particular amino acid sequence. Although the B1 domain of protein G is shown to unfold cooperatively, translocation of calmodulin leads to the formation of intermediates, and these differ on an individual domain level in a manner that depends on whether pulling is from the N or C terminus. The approach presented generates an atomic resolution picture of substrate unfolding and subsequent refolding by unfoldases that can be quite different from results obtained via in vitro denaturation experiments.

  1. Degradation of rotenone in yam bean seeds ( Pachyrhizus sp.) through food processing.

    Science.gov (United States)

    Catteau, Lucy; Lautié, Emmanuelle; Koné, Oumou; Coppée, Marie; Hell, Kerstin; Pomalegni, Charles Bertrand; Quetin-Leclercq, Joëlle

    2013-11-20

    The purpose of this research is to screen different processes that could potentially decrease or even eliminate rotenone, a toxic isoflavonoid, from Pachyrhizus seeds. Yam bean seeds have very interesting nutritional characteristics, especially their high protein and lipid contents, and could potentially increase food security in under-nourished populations. However, they contain rotenone, a natural molecule previously used as an insecticide inhibiting the respiratory mitochondrial chain. It was also proven to be toxic to mammals as chronic exposure leads to the development of Parkinson-like symptoms in rats. As the thermosensitivity of rotenone had been reported, this study tested different processes (drying, roasting, boiling, frying, alcohol extraction), tegument removal, and traditional Beninese culinary recipes. Rotenone was then quantified in end-products by a validated method, associating microwave extraction, solid phase extraction (SPE), and HPLC-UV. With these processes a rotenone removal of up to 80% was obtained. The most effective methods were the drying and roasting of the seeds and the maceration of their flour in local alcohol. Rotenone degradation and elimination were confirmed by cytotoxic assays, effectively inducing a decrease in sample toxicity.

  2. Why chlorate occurs in potable water and processed foods: a critical assessment and challenges faced by the food industry.

    Science.gov (United States)

    Kettlitz, Beate; Kemendi, Gabriella; Thorgrimsson, Nigel; Cattoor, Nele; Verzegnassi, Ludovica; Le Bail-Collet, Yves; Maphosa, Farai; Perrichet, Aurélie; Christall, Birgit; Stadler, Richard H

    2016-06-01

    Recently, reports have been published on the occurrence of chlorate mainly in fruits and vegetables. Chlorate is a by-product of chlorinating agents used to disinfect water, and can be expected to be found in varying concentrations in drinking water. Data on potable water taken at 39 sampling points across Europe showed chlorate to range from foods of 0.01 mg kg(-1). This default MRL has now led to significant problems in the EU, where routinely disinfected water, used in the preparation of food products such as vegetables or fruits, leaves chlorate residues in excess of the default MRL, and in strict legal terms renders the food unmarketable. Due to the paucity of data on the chlorate content of prepared foods in general, we collated chlorate data on more than 3400 samples of mainly prepared foods, including dairy products, meats, fruits, vegetables and different food ingredients/additives. In total, 50.5% of the food samples contained chlorate above 0.01 mg kg(-1), albeit not due to the use of chlorate as a pesticide but mainly due to the occurrence of chlorate as an unavoidable disinfectant by-product. A further entry point of chlorate into foods may be via additives/ingredients that may contain chlorate as a by-product of the manufacturing process (e.g. electrolysis). Of the positive samples in this study, 22.4% revealed chlorate above 0.1 mg kg(-1). In the absence of EU levels for chlorate in water, any future EU regulations must consider the already available WHO guideline value of 0.7 mg l(-1) in potable water, and the continued importance of the usage of oxyhalides for disinfection purposes.

  3. Effects of advanced process approaches on electromigration degradation of Cu on-chip interconnects

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, M.A.

    2007-07-12

    This thesis provides a methodology for the investigation of electromigration (EM) in Cu-based interconnects. An experimental framework based on in-situ scanning electron microscopy (SEM) investigations was developed for that purpose. It is capable to visualize the EM-induced void formation and evolution in multi-level test structures in real time. Different types of interconnects were investigated. Furthermore, stressed and unstressed samples were studied applying advanced physical analysis techniques in order to obtain additional information about the microstructure of the interconnects as well as interfaces and grain boundaries. These data were correlated to the observed degradation phenomena. Correlations of the experimental results to recently established theoretical models were highlighted. Three types of Cu-based interconnects were studied. Pure Cu interconnects were compared to Al-alloyed (CuAl) and CoWP-coated interconnects. The latter two represent potential approaches that address EM-related reliability concerns. It was found that in such interconnects the dominant diffusion path is no longer the Cu/capping layer interface for interconnects as in pure Cu interconnects. Instead, void nucleation occurs at the bottom Cu/barrier interface with significant effects from grain boundaries. Moreover, the in-situ investigations revealed that the initial void nucleation does not occur at the cathode end of the lines but several micrometers away from it. The mean times-to-failure of CuAl and CoWP-coated interconnects were increased by at least one order of magnitude compared to Cu interconnects. The improvements were attributed to the presence of foreign metal atoms at the Cu/capping layer interface. Post-mortem EBSD investigations were used to reveal the microstructure of the tested samples. The data were correlated to the in-situ observations. (orig.)

  4. Project SAFE. Modelling of long-term concrete degradation processes in the Swedish SFR repository

    Energy Technology Data Exchange (ETDEWEB)

    Hoeglund, L.O. [Kemakta Konsult AB, Stockholm (Sweden)

    2001-04-01

    This study concerns the leaching of concrete barriers, in particular the silo construction, in the Swedish SFR repository for low and intermediate level radioactive waste. A conceptual model for the leaching of concrete in a saline groundwater has been proposed based on the increased understanding achieved from research studies presented in the literature. The conceptual model has been used to set up a numerical model for the complex chemical interactions between the cement minerals of the concrete with the groundwater. The calculations show that various chemical reactions are expected to occur in the concrete over time. Different cases have been calculated. The results show that the chemical conditions in the concrete barriers will maintain alkaline for long time. In the most exposed parts of the concrete a high degree of leaching can be expected during the considered 10,000 years, whereas only for the most unfavourable assumptions (initially fractured concrete with groundwater flow-through) the inner parts of the concrete will be degraded to any significant degree.

  5. Project SAFE. Modelling of long-term concrete degradation processes in the Swedish SFR repository

    International Nuclear Information System (INIS)

    Hoeglund, L.O.

    2001-04-01

    This study concerns the leaching of concrete barriers, in particular the silo construction, in the Swedish SFR repository for low and intermediate level radioactive waste. A conceptual model for the leaching of concrete in a saline groundwater has been proposed based on the increased understanding achieved from research studies presented in the literature. The conceptual model has been used to set up a numerical model for the complex chemical interactions between the cement minerals of the concrete with the groundwater. The calculations show that various chemical reactions are expected to occur in the concrete over time. Different cases have been calculated. The results show that the chemical conditions in the concrete barriers will maintain alkaline for long time. In the most exposed parts of the concrete a high degree of leaching can be expected during the considered 10,000 years, whereas only for the most unfavourable assumptions (initially fractured concrete with groundwater flow-through) the inner parts of the concrete will be degraded to any significant degree

  6. High linear energy transfer degradation studies simulating alpha radiolysis of TRU solvent extraction processes

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, Jeremy [Department of Chemical Engineering and Materials Science - University of California Irvine, 916 Engineering Tower, Irvine, CA, 92697 (United States); Miller, George [Department of Chemistry- University of California Irvine, 2046D PS II, Irvine, CA, 92697 (United States); Nilsson, Mikael [Department of Chemical Engineering and Materials Science - University of California Irvine, 916 Engineering Tower, Irvine, CA, 92697 (United States)

    2013-07-01

    Treatment of used nuclear fuel through solvent extraction separation processes is hindered by radiolytic damage from radioactive isotopes present in used fuel. The nature of the damage caused by the radiation may depend on the radiation type, whether it be low linear energy transfer (LET) such as gamma radiation or high LET such as alpha radiation. Used nuclear fuel contains beta/gamma emitting isotopes but also a significant amount of transuranics which are generally alpha emitters. Studying the respective effects on matter of both of these types of radiation will allow for accurate prediction and modeling of process performance losses with respect to dose. Current studies show that alpha radiation has milder effects than that of gamma. This is important to know because it will mean that solvent extraction solutions exposed to alpha radiation may last longer than expected and need less repair and replacement. These models are important for creating robust, predictable, and economical processes that have strong potential for mainstream adoption on the commercial level. The effects of gamma radiation on solvent extraction ligands have been more extensively studied than the effects of alpha radiation. This is due to the inherent difficulty in producing a sufficient and confluent dose of alpha particles within a sample without leaving the sample contaminated with long lived radioactive isotopes. Helium ion beam and radioactive isotope sources have been studied in the literature. We have developed a method for studying the effects of high LET radiation in situ via {sup 10}B activation and the high LET particles that result from the {sup 10}B(n,a){sup 7}Li reaction which follows. Our model for dose involves solving a partial differential equation representing absorption by 10B of an isentropic field of neutrons penetrating a sample. This method has been applied to organic solutions of TBP and CMPO, two ligands common in TRU solvent extraction treatment processes. Rates

  7. Bioresorbable composite screws manufactured via forging process: pull-out, shear, flexural and degradation characteristics.

    Science.gov (United States)

    Felfel, R M; Ahmed, I; Parsons, A J; Rudd, C D

    2013-02-01

    Bioresorbable screws have the potential to overcome some of the complications associated with metallic screws currently in use. Removal of metallic screws after bone has healed is a serious issue which can lead to refracture due to the presence of screw holes. Poly lactic acid (PLA), fully 40 mol% P(2)O(5) containing phosphate unidirectional (P40UD) and a mixture of UD and short chopped strand random fibre mats (P40 70%UD/30%RM) composite screws were prepared via forging composite bars. Water uptake and mass loss for the composite screws manufactured increased significantly to ∼1.25% (P=0.0002) and ∼1.1% (P<0.0001), respectively, after 42 days of immersion in PBS at 37 °C. The initial maximum flexural load for P40 UD/RM and P40 UD composite screws was ∼60% (P=0.0047) and ∼100% (P=0.0037) higher than for the PLA screws (∼190 N), whilst the shear load was slightly higher in comparison to PLA (∼2.2 kN). The initial pull-out strengths for the P40 UD/RM and PLA screws were similar whereas that for P40 UD screws was ∼75% higher (P=0.022). Mechanical properties for the composite screws decreased initially after 3 days of immersion and this reduction was ascribed to the degradation of the fibre/matrix interface. After 3 days interval the mechanical properties (flexural, shear and pull-out) maintained their integrity for the duration of the study (at 42 days). This property retention was attributed to the chemical durability of the fibres used and stability of the matrix properties during the degradation process. It was also deemed necessary to enhance the fibre/matrix interface via use of a coupling agent in order to maintain the initial mechanical properties acquired for the required period of time. Lastly, it is also suggested that the degrading reinforcement fibres may have the potential to buffer any acidic products released from the PLA matrix. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Functional genes to assess nitrogen cycling and aromatic hydrocarbon degradation: primers and processing matter

    Directory of Open Access Journals (Sweden)

    Christopher Ryan Penton

    2013-09-01

    Full Text Available Targeting sequencing to genes involved in key environmental processes, i.e. ecofunctional genes, provides an opportunity to sample nature’s gene guilds to greater depth and help link community structure to process-level outcomes. Vastly different approaches have been implemented for sequence processing and, ultimately, for taxonomic placement of these gene reads. The overall quality of next generation sequence analysis of functional genes is dependent on multiple steps and assumptions of unknown diversity. To illustrate current issues surrounding amplicon read processing we provide examples for three ecofunctional gene groups. A combination of in-silico, environmental and cultured strain sequences was used to test new primers targeting the dioxin and dibenzofuran degrading genes dxnA1, dbfA1, and carAa. The majority of obtained environmental sequences were classified into novel sequence clusters, illustrating the discovery value of the approach. For the nitrite reductase step in denitrification, the well-known nirK primers exhibited deficiencies in reference database coverage, illustrating the need to refine primer-binding sites and/or to design multiple primers, while nirS primers exhibited bias against five phyla. Amino acid-based OTU clustering of these two N-cycle genes from soil samples yielded only 114 unique nirK and 45 unique nirS genus-level groupings, likely a reflection of constricted primer coverage. Finally, supervised and non-supervised OTU analysis methods were compared using the nifH gene of nitrogen fixation, with generally similar outcomes, but the clustering (non-supervised method yielded higher diversity estimates and stronger site-based differences. High throughput amplicon sequencing can provide inexpensive and rapid access to nature’s related sequences by circumventing the culturing barrier, but each unique gene requires individual considerations in terms of primer design and sequence processing and classification.

  9. Linking trajectories of land change, land degradation processes and ecosystem services.

    Science.gov (United States)

    Smiraglia, D; Ceccarelli, T; Bajocco, S; Salvati, L; Perini, L

    2016-05-01

    Land Degradation (LD) is a complex phenomenon resulting in a progressive reduction in the capacity of providing ecosystem services (ES). Landscape transformations promoting an unsustainable use of land often reveal latent processes of LD. An evaluation carried out in respect to the different ecosystem services is nowadays regarded as the most appropriate approach for assessing the effects of LD. The aim of this study is to develop an evaluation framework for identifying the linkages between land changes, LD processes and ES and suggesting Sustainable Land Management (SLM) options suited to reverse (or mitigate) LD impact. A SWOT analysis was carried out with the aim to identify internal and external factors that are favorable (or unfavorable) to achieve the proposed SLM actions. The study areas are the Fortore valley and the Valpadana, in Italy. The main trajectory identified for the Fortore valley is related to land abandonment due to population aging and the progressive emigration started in the 1950s. The most relevant LD processes are soil erosion and geomorphological instability, affecting regulating services such as natural hazard and erosion control. SLM options should consider interventions to contrast geomorphological instability, the promotion of climate smart agriculture and of typical products, and an efficient water resources management. The main trajectories identified for Valpadana are related to urban expansion and farmland abandonment and, as a consequence, land take due to anthropogenic pressure and woodland expansion as the main LD process. The reduction of food production was identified as the most relevant provisioning service affected. SLM should envisage best practices finalized to water saving and soil consumption reduction: efficient irrigation solutions, climate smart agriculture and zero sealing practices. This study highlights the diagnostic value of the suggested approach where LD processes are elicited from land change trajectories

  10. The mechanisms and process of acephate degradation by hydroxyl radical and hydrated electron

    Directory of Open Access Journals (Sweden)

    Yuanyuan Huang

    2018-02-01

    Full Text Available The degradation process of acephate in aqueous solution with ·OH and eaq− produced by 60Co-γ irradiation and electron pulse radiolysis was studied in the present paper. In the aqueous solution, acephate reacted with eaq− and transformed to transient species which can absorb weakly in the wavelength range of 300–400 nm and decay very fast. According to the decay of hydrated electron, the reaction rate constant of eaq− and acephate is (3.51 ± 0.076 × 109 dm3·mol−1·s−1. The transient species produced in the reaction of ·OH and acephate do not distinctly absorb the light in the wavelength range of 300–700 nm, so the decay and kinetics of the transient species cannot determinedirectly. The competing reaction of KSCN oracephate with ·OH were studied to obtain the reaction rate constant of ·OH and acephate, which is (9.1 ± 0.11 × 108 dm3·mol−1·s−1. Although acetylamide and inorganic ions were determined in the products of the reaction of acephate with ·OH or eaq−, the concentration of inorganic ions in the products of the reaction of acephate with ·OH is higher than that in the product of the reaction of acephate with eaq−. Moreover, there were sulfide in the products of the reaction of acephatewith eaq−. The degradation pathways of acephate by ·OH and eaq− were also proposed based on the products from GC-MS.

  11. Degradation of the fluoroquinolone enrofloxacin by electrochemical advanced oxidation processes based on hydrogen peroxide electrogeneration

    Energy Technology Data Exchange (ETDEWEB)

    Guinea, Elena; Garrido, Jose Antonio; Rodriguez, Rosa Maria; Cabot, Pere-Lluis; Arias, Conchita; Centellas, Francesc [Laboratori d' Electroquimica dels Materials i del Medi Ambient, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain); Brillas, Enric, E-mail: brillas@ub.ed [Laboratori d' Electroquimica dels Materials i del Medi Ambient, Departament de Quimica Fisica, Facultat de Quimica, Universitat de Barcelona, Marti i Franques 1-11, 08028 Barcelona (Spain)

    2010-02-15

    Solutions of the veterinary fluoroquinolone antibiotic enrofloxacin in 0.05 M Na{sub 2}SO{sub 4} of pH 3.0 have been comparatively degraded by electrochemical advanced oxidation processes such as anodic oxidation with electrogenerated H{sub 2}O{sub 2} (AO-H{sub 2}O{sub 2}), electro-Fenton (EF), photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF) at constant current density. The study has been performed using an undivided stirred tank reactor of 100 ml and a batch recirculation flow plant of 2.5 l with an undivided filter-press cell coupled to a solar photoreactor, both equipped with a Pt or boron-doped diamond (BDD) anode and a carbon-polytetrafluoroethylene gas diffusion cathode to generate H{sub 2}O{sub 2} from O{sub 2} reduction. In EF, PEF and SPEF, hydroxyl radical (centre dotOH) is formed from Fenton's reaction between added catalytic Fe{sup 2+} and generated H{sub 2}O{sub 2}. Almost total decontamination of enrofloxacin solutions is achieved in the stirred tank reactor by SPEF with BDD. The use of the batch recirculation flow plant showed that this process is the most efficient and can be viable for industrial application, becoming more economic and yielding higher mineralization degree with raising antibiotic content. This is feasible because organics are quickly oxidized with centre dotOH formed from Fenton's reaction and at BDD from water oxidation, combined with the fast photolysis of complexes of Fe(III) with generated carboxylic acids under solar irradiation. The lower intensity of UVA irradiation used in PEF with BDD causes a slower degradation. EF with BDD is less efficient since centre dotOH cannot destroy the most persistent Fe(III)-oxalate and Fe(III)-oxamate complexes. AO-H{sub 2}O{sub 2} with BDD yields the poorest mineralization because pollutants are only removed with centre dotOH generated at BDD. All procedures are less potent using Pt as anode due to the lower production of centre dotOH at its surface. Enrofloxacin

  12. Degradation of the fluoroquinolone enrofloxacin by electrochemical advanced oxidation processes based on hydrogen peroxide electrogeneration

    International Nuclear Information System (INIS)

    Guinea, Elena; Garrido, Jose Antonio; Rodriguez, Rosa Maria; Cabot, Pere-Lluis; Arias, Conchita; Centellas, Francesc; Brillas, Enric

    2010-01-01

    Solutions of the veterinary fluoroquinolone antibiotic enrofloxacin in 0.05 M Na 2 SO 4 of pH 3.0 have been comparatively degraded by electrochemical advanced oxidation processes such as anodic oxidation with electrogenerated H 2 O 2 (AO-H 2 O 2 ), electro-Fenton (EF), photoelectro-Fenton (PEF) and solar photoelectro-Fenton (SPEF) at constant current density. The study has been performed using an undivided stirred tank reactor of 100 ml and a batch recirculation flow plant of 2.5 l with an undivided filter-press cell coupled to a solar photoreactor, both equipped with a Pt or boron-doped diamond (BDD) anode and a carbon-polytetrafluoroethylene gas diffusion cathode to generate H 2 O 2 from O 2 reduction. In EF, PEF and SPEF, hydroxyl radical (·OH) is formed from Fenton's reaction between added catalytic Fe 2+ and generated H 2 O 2 . Almost total decontamination of enrofloxacin solutions is achieved in the stirred tank reactor by SPEF with BDD. The use of the batch recirculation flow plant showed that this process is the most efficient and can be viable for industrial application, becoming more economic and yielding higher mineralization degree with raising antibiotic content. This is feasible because organics are quickly oxidized with ·OH formed from Fenton's reaction and at BDD from water oxidation, combined with the fast photolysis of complexes of Fe(III) with generated carboxylic acids under solar irradiation. The lower intensity of UVA irradiation used in PEF with BDD causes a slower degradation. EF with BDD is less efficient since ·OH cannot destroy the most persistent Fe(III)-oxalate and Fe(III)-oxamate complexes. AO-H 2 O 2 with BDD yields the poorest mineralization because pollutants are only removed with ·OH generated at BDD. All procedures are less potent using Pt as anode due to the lower production of ·OH at its surface. Enrofloxacin decay always follows a pseudo first-order reaction. Its primary aromatic by-products and short intermediates

  13. Degradation of phenylethylamine and tyramine by gamma radiation process and docking studies of its radiolytes

    Energy Technology Data Exchange (ETDEWEB)

    Cardozo, Monique; Souza, Stefânia Priscila de; Lima, Keila dos Santos Cople; França, Tanos Celmar Costa; Lima, Antonio Luis dos Santos, E-mail: santoslima@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Departamanto de Engenharia Quimica; Oliveira, Aline Alves [Universidade de Sao Paulo (USP), São Carlos, SP (Brazil). Instituto de Quimica; Rezende, Cláudia Moraes [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Quimica

    2014-07-01

    Biogenic amines (BA) are toxic low molecular weight organic bases with aliphatic or heterocyclic structures that can be found in several foods. The consumption of food containing large amounts of BA can result in allergic reactions, rash, vomiting, and hypertension. Besides, BA are also known as possible precursors of carcinogens. In the present study we evaluated the effect of different gamma irradiation doses on methanol and water solutions of the BA phenylethylamine and tyramine. Our best results showed that, at a dose of 5 kGy (SI unit used for measurement of absorbed dose of ionizing radiation), it was possible to reduce the content of these two BA up to 85 and 60%, respectively, suggesting that the use of the irradiation process can be an efficient tool for its degradation. Further docking studies also suggested that the radiolytes produced in the irradiation process have more affinity for the human detoxifying enzymes monoaminoxidases type A and B (MAO-A and MAO-B) being, therefore, less toxic than its precursors. (author)

  14. Degradation of black liquor from bioethanol process using coagulation and Fenton-like methods

    Science.gov (United States)

    Muryanto, Muryanto; Sari, Ajeng Arum; Abimanyu, Haznan

    2017-01-01

    Black liquor is one of the main by-products of the pretreatment process in bioethanol production from oil palm empty fruit bunches. Black liquor wastewater releases black coloured effluent with high chemical oxygen demand (COD) and low dissolved oxygen (DO). It had a distinctive dark coloration, high alkalinity (pH=13), high organic content (COD > 50,000 ppm) and a high solid content (TSS > 5,000 ppm). Lignin destruction can be done by using high oxidation from OH radical system such as advanced oxidation processes (AOPs). Thereafter, the high concentration of COD, color, and TSS can be removed. The general aim of the present investigation was to determine degradation of black liquor wastewater by using a combined coagulation and Fenton-like methods. In this research, we use Poly Aluminum Chloride (PAC) as a coagulant and FeCl3.6H2O and H2O2 for Fenton-like's reagent. The process was conducted in jar test at 200 rpm for 30 minutes and after that slowly mixed for 2 hours and left for sedimentation 24 hours. 50 ml black liquor was added with variation dose of 1-5% PAC, and 10 % Fenton-like reagent. Hydroxyl radical was generated by the Fenton-like's reagent (ratio FeCl3.6H2O : H2O2 was varied). The highest decolorization of black liquor 70 % was obtained under 5% PAC coagulant. The pH of the wastewater was reduced from 13.00 to 8.07 after the addition of the coagulant. The decolorization of original black liquor was approximately 58% through the Fenton-like process. The combination of PAC and Fenton-like reagent has able to enhance the decolorization of black liquor up to 97%.

  15. Assessment of DNA degradation induced by thermal and UV radiation processing: implications for quantification of genetically modified organisms.

    Science.gov (United States)

    Ballari, Rajashekhar V; Martin, Asha

    2013-12-01

    DNA quality is an important parameter for the detection and quantification of genetically modified organisms (GMO's) using the polymerase chain reaction (PCR). Food processing leads to degradation of DNA, which may impair GMO detection and quantification. This study evaluated the effect of various processing treatments such as heating, baking, microwaving, autoclaving and ultraviolet (UV) irradiation on the relative transgenic content of MON 810 maize using pRSETMON-02, a dual target plasmid as a model system. Amongst all the processing treatments examined, autoclaving and UV irradiation resulted in the least recovery of the transgenic (CaMV 35S promoter) and taxon-specific (zein) target DNA sequences. Although a profound impact on DNA degradation was seen during the processing, DNA could still be reliably quantified by Real-time PCR. The measured mean DNA copy number ratios of the processed samples were in agreement with the expected values. Our study confirms the premise that the final analytical value assigned to a particular sample is independent of the degree of DNA degradation since the transgenic and the taxon-specific target sequences possessing approximately similar lengths degrade in parallel. The results of our study demonstrate that food processing does not alter the relative quantification of the transgenic content provided the quantitative assays target shorter amplicons and the difference in the amplicon size between the transgenic and taxon-specific genes is minimal. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Simultaneous enhancement of phenolic compound degradations by Acinetobacter strain V2 via a step-wise continuous acclimation process.

    Science.gov (United States)

    Lin, Johnson; Sharma, Vikas; Milase, Ridwaan; Mbhense, Ntuthuko

    2016-06-01

    Phenol degradation enhancement of Acinetobacter strain V2 by a step-wise continuous acclimation process was investigated. At the end of 8 months, three stable adapted strains, designated as R, G, and Y, were developed with the sub-lethal concentration of phenol at 800, 1100, and 1400 mg/L, respectively, from 400 mg/L of V2 parent strain. All strains degraded phenol at their sub-lethal level within 24 h, their growth rate increased as the acclimation process continued and retained their degradation properties even after storing at -80 °C for more than 3 years. All adapted strains appeared coccoid with an ungranulated surface under electron microscope compared to typical rod-shaped parental strain V2 . The adapted Y strain also possessed superior degradation ability against aniline, benzoate, and toluene. This study demonstrated the use of long term acclimation process to develop efficient and better pollutant degrading bacterial strains with potentials in industrial and environmental bioremediation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Degradation of the fungicide carbendazim in aqueous solutions with UV/TiO2 process: Optimization, kinetics and toxicity studies

    International Nuclear Information System (INIS)

    Saien, J.; Khezrianjoo, S.

    2008-01-01

    An attempt was made to investigate the potential of UV-photocatalytic process in the presence of TiO 2 particles for the degradation of carbendazim (C 9 H 9 N 3 O 2 ), a fungicide with a high worldwide consumption but considered as a 'priority hazard substance' by the Water Framework Directive of the European Commission (WFDEC). A circulating upflow photo-reactor was employed and the influence of catalyst concentration, pH and temperature were investigated. The results showed that degradation of this fungicide can be conducted in the both processes of only UV-irradiation and UV/TiO 2 ; however, the later provides much better results. Accordingly, a degradation of more than 90% of fungicide was achieved by applying the optimal operational conditions of 70 mg L -1 of catalyst, natural pH of 6.73 and ambient temperature of 25 deg. C after 75 min irradiation. Under these mild conditions, the initial rate of degradation can be described well by the Langmuir-Hinshelwood kinetic model. Toxicological assessments on the obtained samples were also performed by measurement of the mycelium growth inhibition of Fusarium oxysporum fungus on PDA medium. The results indicate that the kinetics of degradation and toxicity are in reasonably good agreement mainly after 45 min of irradiation; confirming the effectiveness of photocatalytic process

  18. Effect of irradiation and growth regulators on degradation processes in detached soybean leaves

    International Nuclear Information System (INIS)

    Annamalainathan, K.; Pathmanabhan, G.; Manian, K.; Veerannah, L.

    1996-01-01

    Changes in soluble protein profile and chlorophyll (Ch1) content in detached soybean leaves incubated in darkness or light were delayed by application of benzyladenine or indole-3-acetic acid and enhanced by abscisic acid. The degradation in light differed significantly from the degradation in darkness. Chl and proteins were lost at a higher rate in darkness than in light. (author)

  19. Degradation of diclofenac sodium using combined processes based on hydrodynamic cavitation and heterogeneous photocatalysis.

    Science.gov (United States)

    Bagal, Manisha V; Gogate, Parag R

    2014-05-01

    Diclofenac sodium, a widely detected pharmaceutical drug in wastewater samples, has been selected as a model pollutant for degradation using novel combined approach of hydrodynamic cavitation and heterogeneous photocatalysis. A slit venturi has been used as cavitating device in the hydrodynamic cavitation reactor. The effect of various operating parameters such as inlet fluid pressure (2-4 bar) and initial pH of the solution (4-7.5) on the extent of degradation have been studied. The maximum extent of degradation of diclofenac sodium was obtained at inlet fluid pressure of 3 bar and initial pH as 4 using hydrodynamic cavitation alone. The loadings of TiO2 and H2O2 have been optimised to maximise the extent of degradation of diclofenac sodium. Kinetic study revealed that the degradation of diclofenac sodium fitted first order kinetics over the selected range of operating protocols. It has been observed that combination of hydrodynamic cavitation with UV, UV/TiO2 and UV/TiO2/H2O2 results in enhanced extents of degradation as compared to the individual schemes. The maximum extent of degradation as 95% with 76% reduction in TOC has been observed using hydrodynamic cavitation in conjunction with UV/TiO2/H2O2 under the optimised operating conditions. The diclofenac sodium degradation byproducts have been identified using LC/MS analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. FEPs Screening of Processes and Issues in Drip Shield and Waste Package Degradation

    Energy Technology Data Exchange (ETDEWEB)

    K. Mon

    2004-10-11

    The purpose of this report is to evaluate and document the inclusion or exclusion of features, events and processes (FEPs) with respect to drip shield and waste package modeling used to support the Total System Performance Assessment for License Application (TSPA-LA). Thirty-three FEPs associated with the waste package and drip shield performance have been identified (DTN: MO0407SEPFEPLA.000 [DIRS 170760]). A screening decision, either ''included'' or ''excluded,'' has been assigned to each FEP, with the technical bases for screening decisions, as required by the Nuclear Regulatory Commission (NRC) in 10 CFR 63.114 (d, e, and f) [DIRS 156605]. The FEPs analyses in this report address issues related to the degradation and potential failure of the drip shield and waste package over the post closure regulatory period of 10,000 years after permanent closure. For included FEPs, this report summarizes the disposition of the FEP in TSPA-LA. For excluded FEPs, this report provides the technical bases for the screening arguments for exclusion from TSPA-LA. The analyses are for the TSPA-LA base-case design (BSC 2004 [DIRS 168489]), where a drip shield is placed over the waste package without backfill over the drip shield (BSC 2004 [DIRS 168489]). Each FEP includes one or more specific issues, collectively described by a FEP name and description. The FEP description encompasses a single feature, event, or process, or a few closely related or coupled processes, provided the entire FEP can be addressed by a single specific screening argument or TSPA-LA disposition. The FEPs were assigned to associated Project reports, so the screening decisions reside with the relevant subject-matter experts.

  1. FEPs Screening of Processes and Issues in Drip Shield and Waste Package Degradation

    International Nuclear Information System (INIS)

    K. Mon

    2004-01-01

    The purpose of this report is to evaluate and document the inclusion or exclusion of features, events and processes (FEPs) with respect to drip shield and waste package modeling used to support the Total System Performance Assessment for License Application (TSPA-LA). Thirty-three FEPs associated with the waste package and drip shield performance have been identified (DTN: MO0407SEPFEPLA.000 [DIRS 170760]). A screening decision, either ''included'' or ''excluded,'' has been assigned to each FEP, with the technical bases for screening decisions, as required by the Nuclear Regulatory Commission (NRC) in 10 CFR 63.114 (d, e, and f) [DIRS 156605]. The FEPs analyses in this report address issues related to the degradation and potential failure of the drip shield and waste package over the post closure regulatory period of 10,000 years after permanent closure. For included FEPs, this report summarizes the disposition of the FEP in TSPA-LA. For excluded FEPs, this report provides the technical bases for the screening arguments for exclusion from TSPA-LA. The analyses are for the TSPA-LA base-case design (BSC 2004 [DIRS 168489]), where a drip shield is placed over the waste package without backfill over the drip shield (BSC 2004 [DIRS 168489]). Each FEP includes one or more specific issues, collectively described by a FEP name and description. The FEP description encompasses a single feature, event, or process, or a few closely related or coupled processes, provided the entire FEP can be addressed by a single specific screening argument or TSPA-LA disposition. The FEPs were assigned to associated Project reports, so the screening decisions reside with the relevant subject-matter experts

  2. Enzymatic Phorbol Esters Degradation using the Germinated Jatropha Curcas Seed Lipase as Biocatalyst: Optimization Process Conditions by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Avita Kusuma Wardhani

    2016-10-01

    Full Text Available Utilization of Jatropha curcas seed cake is limited by the presence of phorbol esters (PE, which are the main toxic compound and heat stable. The objective of this research was to optimize the reaction conditions of the enzymatic PE degradation of the defatted Jatropha curcas seed cake (DJSC using the acetone-dried lipase from the germinated Jatropha curcas seeds as a biocatalyst. Response Surface Methodology (RSM using three-factors-three-levels Box-Behnken design was used to evaluate the effects of the reaction time, the ratio of buffer volume to DJSC, and the ratio of enzyme to DJSC on PE degradation. The results showed that the optimum conditions of PE degradation were 29.33 h, 51.11 : 6 (mL/g, and 30.10 : 5 (U/g cake for the reaction time, the ratio of buffer volume to DJSC, and the ratio of enzyme to DJSC, respectively. The predicted degradation of PE was 98.96% and not significantly different with the validated data of PE degradation. PE content was 0.035 mg/g, in which it was lower than PE in non-toxic Jatropha seeds. The results indicated that enzymatic degradation of PE might be a promising method for degradation of PE.  Copyright © 2016 BCREC GROUP. All rights reserved Received: 22nd December 2015; Revised: 1st April 2016; Accepted: 14th April 2016 How to Cite: Wardhani, A.K., Hidayat, C., Hastuti, P. (2016. Enzymatic Phorbol Esters Degradation using the Germinated Jatropha Curcas Seed Lipase as Biocatalyst: Optimization Process Conditions by Response Surface Methodology. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (3: 346-353 (doi:10.9767/bcrec.11.3.574.346-353 Permalink/DOI: http://doi.org/10.9767/bcrec.11.3.574.346-353

  3. Microbial degradation processes in radioactive waste repository and in nuclear fuel storage areas

    International Nuclear Information System (INIS)

    Wolfram, J.H.; Rogers, R.D.; Gazso, L.G.

    1997-01-01

    The intent of the workshop organizers was to convene experts in the fields of corrosion and spent nuclear fuels. The major points which evolved from the interaction of microbiologists, material scientists, and fuel storage experts are as follows: Corrosion of basin components as well as fuel containers or cladding is occurring; Water chemistry monitoring, if done in the storage facility does not take into account the microbial component; Microbial influenced corrosion is an area that many have not considered to be an important contributor in the aging of metallurgical materials especially those exposed to a radiation field; Many observations indicate that there is a microbial or biological presence in the storage facilities but these observations have not been correlated with any deterioration or aging phenomena taking place in the storage facility; The sessions on the fundamentals of microbial influenced corrosion and biofilm pointed out that these phenomena are real, occurring on similar materials in other industries and probably are occurring in the wet storage of spent fuel; All agreed that more monitoring, testing, and education in the field of biological mediate processes be performed and financially supported; Loosing the integrity of fuel assemblies can only cause problems, relating to the future disposition of the fuel, safety concerns, and environmental issues; In other rad waste scenarios, biological processes may be playing a role, for instance in the mobility of radionuclides in soil, decomposition of organic materials of the rad waste, gas production, etc. The fundamental scientific presentations discussed the full gamut of microbial processes that relate to biological mediated effects on metallic and non-metallic materials used in the storage and containment of radioactive materials

  4. Effect of process intensifying parameters on the hydrodynamic cavitation based degradation of commercial pesticide (methomyl) in the aqueous solution.

    Science.gov (United States)

    Raut-Jadhav, Sunita; Saini, Daulat; Sonawane, Shirish; Pandit, Aniruddha

    2016-01-01

    Methomyl, a carbamate pesticide, is classified as a pesticide of category-1 toxicity and hence shows harmful effects on both human and aquatic life. In the present work, the degradation of methomyl has been studied by using hydrodynamic cavitation reactor (HC) and its combination with intensifying agents such as H2O2, fenton reagent and ozone (hybrid processes). Initially, the optimization of operating parameters such pH and inlet pressure to the cavitating device (circular venturi) has been carried out for maximizing the efficacy of hydrodynamic cavitation. Further degradation study of methomyl by the application of hybrid processes was carried out at an optimal pH of 2.5 and the optimal inlet pressure of 5 bar. Significant synergetic effect has been observed in case of all the hybrid processes studied. Synergetic coefficient of 5.8, 13.41 and 47.6 has been obtained by combining hydrodynamic cavitation with H2O2, fenton process and ozone respectively. Efficacy of individual and hybrid processes has also been obtained in terms of energy efficiency and extent of mineralization. HC+Ozone process has proved to be the most effective process having highest synergetic coefficient, energy efficiency and the extent of mineralization. The study has also encompassed the identification of intermediate by-products generated during the degradation and has proposed the probable degradation pathway. It has been conclusively established that hydrodynamic cavitation in the presence of intensifying agents can effectively be used for complete degradation of methomyl. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Interaction between aeschynomene spp and rhizobiaceae strains from soils degraded by alluvium mining process

    International Nuclear Information System (INIS)

    Orozco, F H; Medina M; Restrepo, L R; Cuartas, A M

    2001-01-01

    The interaction between isolated bacterial from indigenous legumes of degraded soils by alluvium mining process and different species of aeschynomene was evaluated under nursery conditions. An essay was made in material from mining zone and the experimental design was random blocks with 21 treatment and four repetitions. The results were measured by dry weight of biomass and nodules, foliar nitrogen contains and percentage of occupation in the nodules by strains evaluated. In general terms, evaluated plants showed high specificity by the treatments. Specie of A. Americana was the best, because of its precocity and high production of biomass and nitrogen. Both types of A. falcata responded well to an isolated of rhizobium, while A. americana and A. villosa were better with strains of bradyrhizobium. Nitrogen concentration in all species of aeschynomene was very different. A. villosa presented higher concentration (28-34 9 kg - 1). We found a significant correlation for dry weight between nodules and biomass (r 0.82-0.93 P<0.001). We also found important difference among size of nodules of the species evaluated; it was independent of inoculated strain

  6. Phenol Photocatalytic Degradation by Advanced Oxidation Process under Ultraviolet Radiation Using Titanium Dioxide

    Directory of Open Access Journals (Sweden)

    Ali Nickheslat

    2013-01-01

    Full Text Available Background. The main objective of this study was to examine the photocatalytic degradation of phenol from laboratory samples and petrochemical industries wastewater under UV radiation by using nanoparticles of titanium dioxide coated on the inner and outer quartz glass tubes. Method. The first stage of this study was conducted to stabilize the titanium dioxide nanoparticles in anatase crystal phase, using dip-coating sol-gel method on the inner and outer surfaces of quartz glass tubes. The effect of important parameters including initial phenol concentration, TiO2 catalyst dose, duration of UV radiation, pH of solution, and contact time was investigated. Results. In the dip-coat lining stage, the produced nanoparticles with anatase crystalline structure have the average particle size of 30 nm and are uniformly distributed over the tube surface. The removal efficiency of phenol was increased with the descending of the solution pH and initial phenol concentration and rising of the contact time. Conclusion. Results showed that the light easily passes through four layers of coating (about 105 nm. The highest removal efficiency of phenol with photocatalytic UV/TiO2 process was 50% at initial phenol concentration of 30 mg/L, solution pH of 3, and 300 min contact time. The comparison of synthetic solution and petrochemical wastewater showed that at same conditions the phenol removal efficiency was equal.

  7. Computational enzymology for degradation of chemical warfare agents: promising technologies for remediation processes

    Directory of Open Access Journals (Sweden)

    2017-03-01

    Full Text Available Chemical weapons are a major worldwide problem, since they are inexpensive, easy to produce on a large scale and difficult to detect and control. Among the chemical warfare agents, we can highlight the organophosphorus compounds (OP, which contain the phosphorus element and that have a large number of applications. They affect the central nervous system and can lead to death, so there are a lot of works in order to design new effective antidotes for the intoxication caused by them. The standard treatment includes the use of an anticholinergic combined to a central nervous system depressor and an oxime. Oximes are compounds that reactivate Acetylcholinesterase (AChE, a regulatory enzyme responsible for the transmission of nerve impulses, which is one of the molecular targets most vulnerable to neurotoxic agents. Increasingly, enzymatic treatment becomes a promising alternative; therefore, other enzymes have been studied for the OP degradation function, such as phosphotriesterase (PTE from bacteria, human serum paraoxonase 1 (HssPON1 and diisopropyl fluorophosphatase (DFPase that showed significant performances in OP detoxification. The understanding of mechanisms by which enzymes act is of extreme importance for the projection of antidotes for warfare agents, and computational chemistry comes to aid and reduce the time and costs of the process. Molecular Docking, Molecular Dynamics and QM/MM (quantum-mechanics/molecular-mechanics are techniques used to investigate the molecular interactions between ligands and proteins.

  8. Research on degradation of silk fibroin by combination of electron beam irradiation and hydrothermal processing

    International Nuclear Information System (INIS)

    Nguyen Thi Kim Lan; Dang Van Phu; Le Anh Quoc; Nguyen Quoc Hien

    2014-01-01

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin samples were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at an appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The soluble silk protein content increased from 0.462 to 0.653 mg protein/mg silk fibroin when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  9. FEPs Screening of Processes and Issues in Drip Shield and Waste Package Degradation

    International Nuclear Information System (INIS)

    K.G. Mon; L.A. Rottinghaus

    2004-01-01

    closely related or coupled processes provided that the entire FEP can be addressed by a single specific screening argument or TSPA disposition. Descriptor phrases provide additional detail about the subject and content of the FEP beyond the FEP name and description. The FEPs have been assigned to associated scientific analyses. The assignments were based on the nature of the FEPs so that the analysis and resolution for screening decisions reside with the subject-matter experts in the relevant disciplines. This scientific analysis addresses the screening decisions associated with the FEPs for the Performance Assessment Project Waste Package Degradation Modeling group

  10. FEPs Screening of Processes and Issues in Drip Shield and Waste Package Degradation

    Energy Technology Data Exchange (ETDEWEB)

    K.G. Mon; L.A. Rottinghaus

    2004-03-26

    or event, or a few closely related or coupled processes provided that the entire FEP can be addressed by a single specific screening argument or TSPA disposition. Descriptor phrases provide additional detail about the subject and content of the FEP beyond the FEP name and description. The FEPs have been assigned to associated scientific analyses. The assignments were based on the nature of the FEPs so that the analysis and resolution for screening decisions reside with the subject-matter experts in the relevant disciplines. This scientific analysis addresses the screening decisions associated with the FEPs for the Performance Assessment Project Waste Package Degradation Modeling group.

  11. Degradation Mechanism of Cyanobacterial Toxin Cylindrospermopsin by Hydroxyl Radicals in Homogeneous UV/H2O2 Process

    Science.gov (United States)

    The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometr...

  12. Marine Oil-Degrading Microorganisms and Biodegradation Process of Petroleum Hydrocarbon in Marine Environments: A Review.

    Science.gov (United States)

    Xue, Jianliang; Yu, Yang; Bai, Yu; Wang, Liping; Wu, Yanan

    2015-08-01

    Due to the toxicity of petroleum compounds, the increasing accidents of marine oil spills/leakages have had a significant impact on our environment. Recently, different remedial techniques for the treatment of marine petroleum pollution have been proposed, such as bioremediation, controlled burning, skimming, and solidifying. (Hedlund and Staley in Int J Syst Evol Microbiol 51:61-66, 2001). This review introduces an important remedial method for marine oil pollution treatment-bioremediation technique-which is considered as a reliable, efficient, cost-effective, and eco-friendly method. First, the necessity of bioremediation for marine oil pollution was discussed. Second, this paper discussed the species of oil-degrading microorganisms, degradation pathways and mechanisms, the degradation rate and reaction model, and the factors affecting the degradation. Last, several suggestions for the further research in the field of marine oil spill bioremediation were proposed.

  13. Experimental study of key parameters investigation in turnout crossing degradation process

    NARCIS (Netherlands)

    Liu, X.; Markine, V.L.; Shevtsov, I.; Dollevoet, R.P.B.J.

    2015-01-01

    The continuous increasing demand of public transportation capacity requires the railway network operating in tight schedule. The high transporting volumes not only aggravate the degradation of railway infrastructure but also shorten the time for maintenance. Well-arranged infrastructure maintenance

  14. Degradation characteristic of monoazo, diazo and anthraquinone dye by UV/H{sub 2}O{sub 2} process

    Energy Technology Data Exchange (ETDEWEB)

    Abidin, Che Zulzikrami Azner, E-mail: zulzikrami@unimap.edu.my, E-mail: drfahmi@unimap.edu.my, E-mail: umifazara@unimap.edu.my, E-mail: fatinnadhirah89@gmail.com; Fahmi, Muhammad Ridwan, E-mail: zulzikrami@unimap.edu.my, E-mail: drfahmi@unimap.edu.my, E-mail: umifazara@unimap.edu.my, E-mail: fatinnadhirah89@gmail.com; Fazara, Md Ali Umi, E-mail: zulzikrami@unimap.edu.my, E-mail: drfahmi@unimap.edu.my, E-mail: umifazara@unimap.edu.my, E-mail: fatinnadhirah89@gmail.com; Nadhirah, Siti Nurfatin, E-mail: zulzikrami@unimap.edu.my, E-mail: drfahmi@unimap.edu.my, E-mail: umifazara@unimap.edu.my, E-mail: fatinnadhirah89@gmail.com [School of Environmental Engineering, University Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis (Malaysia)

    2014-10-24

    In this study, the degradation characteristic of monoazo, diazo and anthraquinone dye by UV/H{sub 2}O{sub 2} process was evaluated based on the trend of color, chemical oxygen demand (COD) and total organic carbon (TOC) removal. Three types of dyes consist of monoazo, diazo and anthraquinone dyes were used to compare the degradation mechanism of the dyes. The UV/H{sub 2}O{sub 2} experiments were conducted in a laboratory scale cylindrical glass reactor operated in semi-batch mode. The UV/Vis characterization of monoazo, diazo and anthraquinone dye indicated that the rapid degradation of the dyes by UV/H{sub 2}O{sub 2} process is meaningful with respect to decolourization, as a result of the azo bonds and substitute antraquinone chromophore degradation. However, this process is not efficient for aromatic amines removal. The monoazo MO was difficult to be decolorized than diazo RR120 dye, which imply that number of sulphonic groups in the dye molecules determines the reactivity with hydroxyl radical. The increased in COD removal is the evidence for oxidation and decreased in carbon content of dye molecules. TOC removal analysis shows that low TOC removal of monoazo MO and diazo RR120, as compared to anthraquinone RB19 may indicate an accumulation of by-products that are resistant to the H{sub 2}O{sub 2} photolysis.

  15. Community Structure and Succession Regulation of Fungal Consortia in the Lignocellulose-Degrading Process on Natural Biomass

    Directory of Open Access Journals (Sweden)

    Baoyu Tian

    2014-01-01

    Full Text Available The study aims to investigate fungal community structures and dynamic changes in forest soil lignocellulose-degrading process. rRNA gene clone libraries for the samples collected in different stages of lignocellulose degradation process were constructed and analyzed. A total of 26 representative RFLP types were obtained from original soil clone library, including Mucoromycotina (29.5%, unclassified Zygomycetes (33.5%, Ascomycota (32.4%, and Basidiomycota (4.6%. When soil accumulated with natural lignocellulose, 16 RFLP types were identified from 8-day clone library, including Basidiomycota (62.5%, Ascomycota (36.1%, and Fungi incertae sedis (1.4%. After enrichment for 15 days, identified 11 RFLP types were placed in 3 fungal groups: Basidiomycota (86.9%, Ascomycota (11.5%, and Fungi incertae sedis (1.6%. The results showed richer, more diversity and abundance fungal groups in original forest soil. With the degradation of lignocellulose, fungal groups Mucoromycotina and Ascomycota decreased gradually, and wood-rotting fungi Basidiomycota increased and replaced the opportunist fungi to become predominant group. Most of the fungal clones identified in sample were related to the reported lignocellulose-decomposing strains. Understanding of the microbial community structure and dynamic change during natural lignocellulose-degrading process will provide us with an idea and a basis to construct available commercial lignocellulosic enzymes or microbial complex.

  16. Community structure and succession regulation of fungal consortia in the lignocellulose-degrading process on natural biomass.

    Science.gov (United States)

    Tian, Baoyu; Wang, Chunxiang; Lv, Ruirui; Zhou, Junxiong; Li, Xin; Zheng, Yi; Jin, Xiangyu; Wang, Mengli; Ye, Yongxia; Huang, Xinyi; Liu, Ping

    2014-01-01

    The study aims to investigate fungal community structures and dynamic changes in forest soil lignocellulose-degrading process. rRNA gene clone libraries for the samples collected in different stages of lignocellulose degradation process were constructed and analyzed. A total of 26 representative RFLP types were obtained from original soil clone library, including Mucoromycotina (29.5%), unclassified Zygomycetes (33.5%), Ascomycota (32.4%), and Basidiomycota (4.6%). When soil accumulated with natural lignocellulose, 16 RFLP types were identified from 8-day clone library, including Basidiomycota (62.5%), Ascomycota (36.1%), and Fungi incertae sedis (1.4%). After enrichment for 15 days, identified 11 RFLP types were placed in 3 fungal groups: Basidiomycota (86.9%), Ascomycota (11.5%), and Fungi incertae sedis (1.6%). The results showed richer, more diversity and abundance fungal groups in original forest soil. With the degradation of lignocellulose, fungal groups Mucoromycotina and Ascomycota decreased gradually, and wood-rotting fungi Basidiomycota increased and replaced the opportunist fungi to become predominant group. Most of the fungal clones identified in sample were related to the reported lignocellulose-decomposing strains. Understanding of the microbial community structure and dynamic change during natural lignocellulose-degrading process will provide us with an idea and a basis to construct available commercial lignocellulosic enzymes or microbial complex.

  17. DBP formation from degradation of DEET and ibuprofen by UV/chlorine process and subsequent post-chlorination.

    Science.gov (United States)

    Aghdam, Ehsan; Xiang, Yingying; Sun, Jianliang; Shang, Chii; Yang, Xin; Fang, Jingyun

    2017-08-01

    The formation of disinfection by-products (DBPs) from the degradation of N,N-diethyl-3-methyl benzoyl amide (DEET) and ibuprofen (IBP) by the ultraviolet irradiation (UV)/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H 2 O 2 process. The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H 2 O 2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species (RCS) and hydroxyl radicals (HO) in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50% after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine (TOCl), respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H 2 O 2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%-63% higher, likely due to the generation of more DBP precursors from the attack of RCS, in addition to HO. Copyright © 2017. Published by Elsevier B.V.

  18. Lessons learned from the Febex in situ test: geochemical processes associated to the microbial degradation and gas generation

    International Nuclear Information System (INIS)

    Fernandez, A. M.; Sanchez, D.M.; Melon, A.; Mingarro, M.; Wieczorek, K.

    2012-01-01

    existence of gaps between the bentonite blocks, which favour the development and growth of inactive and dormant cells or spores belonging to the original bentonite. In this work, the observed geochemical and corrosion processes influenced both by organic matter degradation and micro-organisms in the 1:1 scale FEBEX in situ test (Grimsel, Switzerland) are described. This test consists of two heaters, simulating radioactive waste containers, emplaced in a horizontal gallery and surrounded by a highly compacted bentonite barrier. Samples from pore water, gases and bentonite (SHSDI-01: clay in contact with AISI 316L metal; S29 and BSBI-26: clay in contact with carbon steel) have been analysed. The samples were obtained during the test and the dismantling of the heater 1 after six years of experiment. The solid samples were analysed by XRD, SEM, XPS, FTIR, ATD-TG and chemical analysis; the water samples by IC and ICP-OES, and the gases by gas chromatography. Different geochemical processes have been detected as a function of the temperature and water content of the samples. When the water content is high, there are aerobic respiration and fermentation processes, anaerobic respiration with SO 4 2- as electron acceptor, and anaerobic production of methane with CO 2 as electron acceptor. In a first phase, both oxygen consumption and an increase of CH 4 and CO 2 is observed. Afterwards, there is a reduction of sulfates by SRB bacteria, which provokes corrosion processes. As a consequence, a precipitation of sulphurs, iron oxy-hydroxides and carbonates occurs, as well as H 2 generation. There is an increase of the iron content in the smectite and the neo-formation of zeolites. However this alteration is punctual and localized. The redox potential of the bentonite pore water was of -284 mV. When the temperature is high and water content is low, other processes take place

  19. Investigation of optimum conditions and costs estimation for degradation of phenol by solar photo-Fenton process

    Science.gov (United States)

    Gar Alalm, Mohamed; Tawfik, Ahmed; Ookawara, Shinichi

    2017-03-01

    In this study, solar photo-Fenton reaction using compound parabolic collectors reactor was assessed for removal of phenol from aqueous solution. The effect of irradiation time, initial concentration, initial pH, and dosage of Fenton reagent were investigated. H2O2 and aromatic intermediates (catechol, benzoquinone, and hydroquinone) were quantified during the reaction to study the pathways of the oxidation process. Complete degradation of phenol was achieved after 45 min of irradiation when the initial concentration was 100 mg/L. However, increasing the initial concentration up to 500 mg/L inhibited the degradation efficiency. The dosage of H2O2 and Fe+2 significantly affected the degradation efficiency of phenol. The observed optimum pH for the reaction was 3.1. Phenol degradation at different concentration was fitted to the pseudo-first order kinetic according to Langmuir-Hinshelwood model. Costs estimation for a large scale reactor based was performed. The total costs of the best economic condition with maximum degradation of phenol are 2.54 €/m3.

  20. Detection of Degradation Effects in Field-Aged c-Si Solar Cells through IR Thermography and Digital Image Processing

    Directory of Open Access Journals (Sweden)

    E. Kaplani

    2012-01-01

    Full Text Available Due to the vast expansion of photovoltaic (PV module production nowadays, a great interest is shown in factors affecting PV performance and efficiency under real conditions. Particular attention is being given to degradation effects of PV cells and modules, which during the last decade are seen to be responsible for significant power losses observed in PV systems. This paper presents and analyses degradation effects observed in severely EVA discoloured PV cells from field-aged modules operating already for 18–22 years. Temperature degradation effects are identified through IR thermography in bus bars, contact solder bonds, blisters, hot spots, and hot areas. I-V curve analysis results showed an agreement between the source of electrical performance degradation and the degradation effects in the defected cell identified by the IR thermography. Finally, an algorithm was developed to automatically detect EVA discoloration in PV cells through processing of the digital image alone in a way closely imitating human perception of color. This nondestructive and noncostly solution could be applied in the detection of EVA discoloration in existing PV installations and the automatic monitoring and remote inspection of PV systems.

  1. THE USE OF TIO2-ZEOLIT AS A CATALYST ON THE DEGRADATION PROCESS OF ERIONIL RED DYE

    Directory of Open Access Journals (Sweden)

    Agustin Sumartono

    2010-06-01

    Full Text Available Degradation of erionil red dye using photo catalytic processes with TiO2-zeolit as a catalyst was carried out. Degradation of the dye was observed in 10 L volume, and erionil red dye was used as a model of organic pollutant. The parameters examinated were  intensity of the spectrum, the decrease of pH, percentage of degradation, and the efectifity TiO2-zeolit  as a catalyst. The use of UV lamp and TiO2-zeolit as a catalyst showed a good results because the dye could be degraded. This could be seen from the decreasing of the intensity of the spectrum  24 h after illumination. The pH of erionil red increased from around 4 into 5.5 which is still acidic. Effectivity of TiO2 composit as a catalyst could be used only two times. The compound resulted from degradation that could be detected using HPLC was oxalic acid.   Keywords: dye, erionil red, photocatalytic, TiO2

  2. A study of enhanced performance of VUV/UV process for the degradation of micropollutants from contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Bagheri, Mehdi; Mohseni, Madjid, E-mail: madjid.mohseni@ubc.ca

    2015-08-30

    Highlights: • Developing a comprehensive CFD simulation tool for VUV/UV photoreactors modeling. • Analysing impact of reactor hydrodynamics on the AOP performance of VUV/UV process. • Cutting the energy cost of VUV/UV process by means of improved-photoreactor design. • Experimentally verifying the CFD results using a VUV/UV prototype photoreactor. - Abstract: VUV/UV is a chemical-free and straightforward solution for the degradation of emerging contaminants from water sources. The objective of this work was to investigate the feasibility of VUV/UV advanced oxidation process for the effective degradation of a target micropollutant, atrazine, under continuous flow operation of 0.5–6.5 L/min. To provide an in-depth understanding of process, a comprehensive computational fluid dynamics (CFD) model, incorporating flow hydrodynamics, 185 nm VUV and 254 nm UV radiation propagation along with a complete kinetic scheme, was developed and validated experimentally. The experimental degradation rates and CFD predicted values showed great consistency with less than 2.9% average absolute relative deviation (AARD). Utilizing the verified model, energy-efficiency of the VUV/UV process under a wide range of reactor configurations was assessed in terms of electrical energy-per-order (EEO), ·OH concentration as well as delivered UV and VUV dose distributions. Thereby, the extent of mixing and circulation zones was found as key parameter controlling the treatment economy and energy-efficiency of the VUV/UV process. Utilizing a CFD-driven baffle design strategy, an improved VUV/UV process with up to 72% reduction in the total electrical energy requirement of atrazine degradation was introduced and verified experimentally.

  3. Quantitative modelling of the degradation processes of cement grout. Project CEMMOD

    Energy Technology Data Exchange (ETDEWEB)

    Grandia, Fidel; Galindez, Juan-Manuel; Arcos, David; Molinero, Jorge (Amphos21 Consulting S.L., Barcelona (Spain))

    2010-05-15

    Grout cement is planned to be used in the sealing of water-conducting fractures in the deep geological storage of spent nuclear fuel waste. The integrity of such cementitious materials should be ensured in a time framework of decades to a hundred of years as mimum. However, their durability must be quantified since grout degradation may jeopardize the stability of other components in the repository due to the potential release of hyperalkaline plumes. The model prediction of the cement alteration has been challenging in the last years mainly due to the difficulty to reproduce the progressive change in composition of the Calcium-Silicate-Hydrate (CSH) compounds as the alteration proceeds. In general, the data obtained from laboratory experiments show a rather similar dependence between the pH of pore water and the Ca-Si ratio of the CSH phases. The Ca-Si ratio decreases as the CSH is progressively replaced by Si-enriched phases. An elegant and reasonable approach is the use of solid solution models even keeping in mind that CSH phases are not crystalline solids but gels. An additional obstacle is the uncertainty in the initial composition of the grout to be considered in the calculations because only the recipe of low-pH clinker is commonly provided by the manufacturer. The hydration process leads to the formation of new phases and, importantly, creates porosity. A number of solid solution models have been reported in literature. Most of them assumed a strong non-ideal binary solid solution series to account for the observed changes in the Ca-Si ratios in CSH. However, it results very difficult to reproduce the degradation of the CSH in the whole Ca-Si range of compositions (commonly Ca/Si=0.5-2.5) by considering only two end-members and fixed nonideality parameters. Models with multiple non-ideal end-members with interaction parameters as a function of the solid composition can solve the problem but these can not be managed in the existing codes of reactive

  4. A Doping Lattice of Aluminum and Copper with Accelerated Electron Transfer Process and Enhanced Reductive Degradation Performance

    Science.gov (United States)

    Zhang, Lin; Gao, Xue; Zhang, Zhixuan; Zhang, Mingbo; Cheng, Yiqian; Su, Jixin

    2016-08-01

    Treatment of azo dye effluents has received increasing concerns over the years due to their potential harms to natural environment and human health. The present study described the degrading ability of the as-synthesized crystalline Al-Cu alloys for removal of high-concentration Acid Scarlet 3R in alkaline aqueous solutions and its degradation mechanism. Al-Cu alloy particles with Al/Cu ratios 19:1 were successfully synthesized by high-energy mechanical milling. Characterization results showed that 10 h mechanical alloying process could lead to the formation of crystalline Al(Cu) solid solution. Batch experiment results confirmed the excellent ability of Al-Cu alloy particles for the degradation of 3R in aqueous solution. Under a certain condition ([Al-Cu]0 = 2 g/L, [3R]0 = 200 mg/L, [NaCl]0 = 25 g/L, initial pH = 10.9), the 3R could be completely degraded within only 3 min. It was also found that the degradation reaction followed zero-order kinetics model with respect to the initial dye concentration. The intermediate compounds were identified by UV-vis, FT-IR and HPLC-MS, and a pathway was proposed. Additionally, post-treatment Al-Cu alloy particles were characterized by SEM and TEM, and the results showed that the degradation might be attributed to the corrosion effect of Al-Cu alloys.

  5. Study of the degradation performance (TOC, BOD, and toxicity) of bisphenol A by the photo-Fenton process.

    Science.gov (United States)

    Pérez-Moya, M; Kaisto, T; Navarro, M; Del Valle, L J

    2017-03-01

    Degradation of bisphenol A (BPA, 0.5 L, 30 mg L -1 ) was studied by photo-Fenton treatment, while Fenton reagents were variables. The efficiency of the degradation process was evaluated by the reduction of total organic carbon (TOC), the biochemical oxygen demand (BOD), and toxicity. For toxicity analysis, bacterial methods were found infeasible, but the in vitro assay of VERO cells culture was successfully applied. Experiments according to a 2 2 design of experiments (DOE) with star points and three center points for statistical validity allowed selecting those process conditions (Fe(II) and H 2 O 2 load) that maximized the process performance. Photo-Fenton process effectively eliminated BPA and partly degraded its by-products (residual TOC TOC = 92 %) was attained. Toxicity was also detected to 50 % of cellular mortality even at long reaction times. However, 40.25 mg L -1 of H 2 O 2 decreased residual TOC to 70 % while cell mortality decreased down to 25 %. With more H 2 O 2 , the residual TOC decreased down to 15 % but cell mortality remained within the 20-25 % level. Photo-Fenton increased the biodegradability and reduced the toxicity of the studied sample.

  6. Photocatalysis applied to concrete products - Part 3: Practical relevance and modeling of the degradation process

    NARCIS (Netherlands)

    Hunger, M.; Hüsken, G.; Brouwers, H.J.H.

    2009-01-01

    The third and last part of this article series concludes the characterization of influencing factors on the degradation performance illustrated by the influence of pigments. Furthermore, the results of an accelerated durability test carried out on coated samples described in the second part of this

  7. Mechanical and degradation property improvement in a biocompatible Mg-Ca-Sr alloy by thermomechanical processing.

    Science.gov (United States)

    Henderson, Hunter B; Ramaswamy, Vidhya; Wilson-Heid, Alexander E; Kesler, Michael S; Allen, Josephine B; Manuel, Michele V

    2018-04-01

    Magnesium-based alloys have attracted interest as a potential material to comprise biomedical implants that are simultaneously high-strength and temporary, able to provide stabilization before degrading safely and able to be excreted by the human body. Many alloy systems have been evaluated, but this work reports on improved properties through hot extrusion of one promising alloy: Mg-1.0 wt% Ca-0.5 wt%Sr. This alloy has previously demonstrated promising toxicity and degradation properties in the as-cast and rolled conditions. In the current study extrusion causes a dramatic improvement in the mechanical properties in tension and compression, as well as a low in vitro degradation rate. Microstructure (texture, second phase distribution, and grain size), bulk mechanical properties, flow behavior, degradation in simulated body fluid, and effect on osteoblast cyctotoxicity are evaluated and correlated to extrusion temperature. Maximum yield strength of 300 MPa (above that of annealed 316 stainless steel) with 10% elongation is observed, making this alloy competitive with existing implant materials. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  8. Degradation Processes in High-Power Diode Lasers under External Optical Feedback

    DEFF Research Database (Denmark)

    Tomm, Jens. W.; Hempel, Martin; Petersen, Paul Michael

    2013-01-01

    The effect of moderate external feedback on the gradual degradation of 808 nm emitting AlGaAs-based high-power broad-area diode lasers is analyzed. Eventually the quantum well that actually experiences the highest total optical load remains unaffected by the aging, while severe impact...

  9. Bio-Electro-Fenton process for the degradation of Non-Steroidal Anti-Inflammatory Drugs in wastewater

    DEFF Research Database (Denmark)

    Nadais, Helena; Li, Xiaohu; Alves, Nadine

    2018-01-01

    Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are ubiquitous municipal wastewater pollutants of which several are resistant to degradation in conventional wastewater treatment, and represent a major environmental health concern worldwide. An alternative treatment, the bio-electro-Fenton process......, has received increasing attention in past years. In this process the strong oxidant •HO is formed using the electrons derived from bacterial oxidation of organic substrate. In this work, a laboratory scale microbial electrolysis cell based bio-electro-Fenton process was developed for the treatment...

  10. Factorial experimental design for the optimization of catalytic degradation of malachite green dye in aqueous solution by Fenton process

    Directory of Open Access Journals (Sweden)

    A. Elhalil

    2016-09-01

    Full Text Available This work focuses on the optimization of the catalytic degradation of malachite green dye (MG by Fenton process “Fe2+/H2O2”. A 24 full factorial experimental design was used to evaluate the effects of four factors considered in the optimization of the oxidative process: concentration of MG (X1, concentration of Fe2+ (X2, concentration of H2O2 (X3 and temperature (X4. Individual and interaction effects of the factors that influenced the percentage of dye degradation were tested. The effect of interactions between the four parameters shows that there is a dependency between concentration of MG and concentration of Fe2+; concentration of Fe2+ and concentration of H2O2, expressed by the great values of the coefficient of interaction. The analysis of variance proved that, the concentration of MG, the concentration of Fe2+ and the concentration of H2O2 have an influence on the catalytic degradation while it is not the case for the temperature. In the optimization, the great dependence between observed and predicted degradation efficiency, the correlation coefficient for the model (R2=0.986 and the important value of F-ratio proved the validity of the model. The optimum degradation efficiency of malachite green was 93.83%, when the operational parameters were malachite green concentration of 10 mg/L, Fe2+ concentration of 10 mM, H2O2 concentration of 25.6 mM and temperature of 40 °C.

  11. The probability distribution of maintenance cost of a system affected by the gamma process of degradation: Finite time solution

    International Nuclear Information System (INIS)

    Cheng, Tianjin; Pandey, Mahesh D.; Weide, J.A.M. van der

    2012-01-01

    The stochastic gamma process has been widely used to model uncertain degradation in engineering systems and structures. The optimization of the condition-based maintenance (CBM) policy is typically based on the minimization of the asymptotic cost rate. In the financial planning of a maintenance program, however, a more accurate prediction interval for the cost is needed for prudent decision making. The prediction interval cannot be estimated unless the probability distribution of cost is known. In this context, the asymptotic cost rate has a limited utility. This paper presents the derivation of the probability distribution of maintenance cost, when the system degradation is modelled as a stochastic gamma process. A renewal equation is formulated to derive the characteristic function, then the discrete Fourier transform of the characteristic function leads to the complete probability distribution of cost in a finite time setting. The proposed approach is useful for a precise estimation of prediction limits and optimization of the maintenance cost.

  12. Effects of different processing methods of flaxseed on ruminal degradability and in vitro post-ruminal nutrient disappearance

    DEFF Research Database (Denmark)

    Lashkari, Saman

    2015-01-01

    The aim of the study was to determine the effects of different heat-processing methods of flaxseed on the in situ effective dry matter degradability (EDMD) and the in situ effective crude protein degradability (ECPD). The treatments included roasting, steep roasting, rolled roasting, rolled steep...... roasting, microwave irradiation and extrusion. Three rumen-fistulated sheep were used for in situ incubations. Furthermore, the effects of heat-processing methods on post-ruminal in vitro nutrient disappearance and total tract disappearance were measured by a three-step in vitro technique. The seeds were...... roasted and extruded at 140°C to 145°C. One lot of roasted seeds was gradually cooled for about 1 h (roasting) and another lot was held in temperature isolated barrels for 45 min (steep roasting). Moreover, roasted and steep roasted flaxseed was rolled in a roller mill. The lowest and highest EDMD...

  13. Sulfate radical-induced degradation of Acid Orange 7 by a new magnetic composite catalyzed peroxymonosulfate oxidation process.

    Science.gov (United States)

    Chen, Dan; Ma, Xiaolong; Zhou, Jizhi; Chen, Xi; Qian, Guangren

    2014-08-30

    We synthesized a novel magnetic composite, Fe3O4/Cu(Ni)Cr-LDH, as a heterogeneous catalyst for the degradation of organic dyes in the solution using sulfate radical-based advanced oxidation processes. The physicochemical properties of the composite synthesized via two-step microwave hydrothermal method were characterized by several techniques, such as X-ray diffraction (XRD), inductively coupled plasma (ICP), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The degradation tests were performed at 25°C with Acid Orange 7 (AO7) initial concentration of 25mg/L and AO7/peroxymonosulfate (PMS) molar ratio of 1:10, which showed that the complete degradation by Fe3O4/Cu1.5Ni0.5Cr-LDH could be achieved and the mineralization rate could reach 46%. PMS was activated by Cu (II) and Fe (II/III) of Fe3O4/Cu(Ni)Cr-LDH to generate sulfate radicals (SO4(-)). Subsequently, the organic functional groups of AO7 molecules were destroyed by sulfate radicals (SO4(-)), inducing the degradation of AO7. Moreover, the catalytic behavior of the catalysts could be reused five times. Therefore, our work suggested that the Fe3O4/Cu(Ni)Cr-LDH composite could be applied widely for the treatment of organic dyes in wastewater. Copyright © 2014. Published by Elsevier B.V.

  14. Degradation of biogenetic amines by gamma radiation process and identification by GC/MS

    Energy Technology Data Exchange (ETDEWEB)

    Cardozo, Monique; Souza, Stefania P. de; Lima, Keila dos S.C.; Lima, Antonio L. dos S., E-mail: santoslima@ime.eb.br [Departamento de Quimica - IME, Instituto Militar de Engenharia, RJ (Brazil)

    2011-07-01

    , using a research radiator with Cs-137 source and maximum dose rate of 1,8kGy/h. Dosimetry was performed with the calculation of the source exposure time using a specific program for the irradiator. For identification of amines it was used gas chromatography associated with a mass detector. The chromatographic conditions used were: interface temperature at 200 degree C, SCAN mode for m/z 15 to 300, helium mobile phase, manual injection, split rate of 1/5 and flow rate of 1.00mL/min. The heating was linear from 40 degree C to 300 degree C, with a rate of 10 degree C/min. Chromatographic separation was performed with column RTx-5MS, 30m x 0,25mm x 0,25 {mu}m, stationary phase 5% diphenyl - 95% dimethylpolysiloxane. The content of the amines after the irradiation process suffered considerable reduction. Tryptamine was more radiosensitive being reduced by about 85% at 1kGy, 99% at 3kGy and 100% at 5kGy. The b-phenylethylamine was reduced from its initial amount in about 20% at 1kGy, 70% at 3kGy and 85% at 5kGy. Tyramine showed less sensitivity to gamma radiation with reduction only 20% at 1kGy, 50% at 3kGy and 60% at 5kGy. These results show that the use of the irradiation process was efficient in the degradation of the amines tested. (author)

  15. Degradation of biogenetic amines by gamma radiation process and identification by GC/MS

    International Nuclear Information System (INIS)

    Cardozo, Monique; Souza, Stefania P. de; Lima, Keila dos S.C.; Lima, Antonio L. dos S.

    2011-01-01

    , using a research radiator with Cs-137 source and maximum dose rate of 1,8kGy/h. Dosimetry was performed with the calculation of the source exposure time using a specific program for the irradiator. For identification of amines it was used gas chromatography associated with a mass detector. The chromatographic conditions used were: interface temperature at 200 degree C, SCAN mode for m/z 15 to 300, helium mobile phase, manual injection, split rate of 1/5 and flow rate of 1.00mL/min. The heating was linear from 40 degree C to 300 degree C, with a rate of 10 degree C/min. Chromatographic separation was performed with column RTx-5MS, 30m x 0,25mm x 0,25 μm, stationary phase 5% diphenyl - 95% dimethylpolysiloxane. The content of the amines after the irradiation process suffered considerable reduction. Tryptamine was more radiosensitive being reduced by about 85% at 1kGy, 99% at 3kGy and 100% at 5kGy. The b-phenylethylamine was reduced from its initial amount in about 20% at 1kGy, 70% at 3kGy and 85% at 5kGy. Tyramine showed less sensitivity to gamma radiation with reduction only 20% at 1kGy, 50% at 3kGy and 60% at 5kGy. These results show that the use of the irradiation process was efficient in the degradation of the amines tested. (author)

  16. A Modified Soil Quality Index to Assess the Influence of Soil Degradation Processes on Desertification Risk: The Apulia Case

    Directory of Open Access Journals (Sweden)

    Valeria Ancona

    2010-10-01

    Full Text Available Apulia is one of the most prone Italian regions to soil alteration phenomena, due to geographical and climatic conditions and also to human activities’ impact. In this study, in order to investigate regional soil degradation processes, following the “European Directive for Soil Protection”, the ESA’s method has been adopted. It is based on the use of an indicator’s set to assess the desertification risk. This approach simplifies the diagnosis and monitoring of soil degradation processes, defining their status and trend. Special attention has been given to Soil Quality Index (SQI determined by six predisposing indicators (parent material, soil texture, rock fragment, soil depth, drainage and slope grade. The integration in the SQI calculation of two additional soil parameters (organic matter content and soil salinity has been considered particularly significant. In fact, through the evaluation of a so “modified SQI” and the Apulia land use too, it could be possible to assess the role of agriculture management on soil degradation processes, which predisposing regional area to desertification threat. Moreover this approach provides short, but accurate, information thanks to GIS integration, which defines phenomena in detail, offering helpful planning tools.

  17. Evaluation of Degradation Kinetic of Tomato Paste Color in Heat Processing and Modeling of These Changes by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    M. Ganjeh

    2015-12-01

    Full Text Available Color is an important qualitative factor in tomato products such as tomato paste which is affected by heat processing. The main goal of this study was to evaluate the degradation kinetics of tomato paste color during heat processing by Arrhenius equation and modeling of these changes by response surface methodology (RSM. Considering this purpose, tomato paste was processed at three temperatures of 60, 70 and 80 °C for 25-100 minutes and by three main color indices including L, a and b, a/b ratio, total color difference (TCD, Saturation index (SI and hue angle (HU was analyzed. Degradation kinetics of these parameters was evaluated by Arrhenius equation and their changing trends were modeled by RSM. All parameters except TCA (zero order followed a first order reaction. The b index by highest and TCA and a/b by least activation energies had the maximum and minimum sensitivity to the temperature changes, respectively. Also, TCD and b had the maximum and minimum changing rates, respectively. All responses were influenced by independent parameters (the influence of temperature was more than time and RSM was capable of modeling and predicting these responses. In general, Arrhenius equation was appropriate to evaluate degradation kinetics of tomato paste color changes and RSM was able to estimate independent and interaction effects of time and temperature so that quadratic models were capable to predict these changes by a high accuracy (R2 > 0.95.

  18. Characterization of {sup 238}U, {sup 232}Th, {sup 40}K, and {sup 226}Ra in NORM and Air Particulate Occurring from Phosphate Processing Facility

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yoon Hee; Lim, Jong Myoung; Ji, Young Yong; Kim, Hyun Cheol; Kim, Chang Jong; Park, Ji Yong; Chung, Kun Ho; Kang, Mun Ja [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, radio-activities of {sup 238}U, {sup 232}Th, {sup 40}K, and {sup 226}Ra occurring in raw materials and by-products at phosphate processing facility were complementally determined using ED-XRF, γ-spectrometry and ICP-MS method. Although the degree of immersion in the human body varies depending on the particle size and density, the particle size is especially used as a key factor in assessing dose. Thus, size distribution characteristics of {sup 238}U concentrations in airborne particulates collected at the phosphate processing facility were also evaluated. The naturally occurring radioactive materials (NORM) are widely spread throughout the environment, it occupies the largest part of public radioactivity exposure. According to report of the US National Academy of Sciences, 82% of the human radiation dose received annually comes from the natural radionuclides. Radiation exposure doses from natural radionuclides is not significantly concerned level compared to those from artificial radionuclides which could be released into the environment by nuclear tests and power plant accident. It could make a serious risk problem to unspecific public when exposed to the natural radionuclides during long-term period at high activity concentration levels. Therefore, it is essential to make a professional and systematic approach for the proper handling and diminution.

  19. Report of the Committee of inquiry into a fire which occurred on 18 March 1987 in a radioisotope processing cell, Building 54 at the Lucas Heights Research Laboratories

    International Nuclear Information System (INIS)

    1987-01-01

    At about 1745 hours on Wednesday, 18 March 1987 a fire occurred in a small charcoal filter inside a processing cell (hot cell) in Building 54 at the Lucas Heights Research Laboratories (LHRL). This cell was being used to process irradiated uranium to separate the radioactive isotope molybdenum-99. Some radioactive contamination escaped from the hot cell into the operating area and three AAEC officers were found to have minor radioactive contamination on their skin/hair. The majority of the radioactive material released from the fire was trapped by the main filters outside the cell. The total amounts of radioactive noble gas and of radioiodine released to the environment during the week in which the fire occurred were within the normal range of discharge and were 53% and 2.1%, respectively, of the weekly limit authorised by the NSW Department of Health. On the evidence available to it, the Committee concludes that the fire was caused by spontaneous combustion in the charcoal filter used to trap radioactive gases released by the operations in the hot cell; the mechanism causing the fire cannot be clearly established at this stage; no member of AAEC staff, NSW emergency services personnel or the general public suffered, or will suffer, any adverse health effects from radioactivity as a result of the accident

  20. Organic contaminants degradation from the S(IV) autoxidation process catalyzed by ferrous-manganous ions: A noticeable Mn(III) oxidation process.

    Science.gov (United States)

    Zhang, Jiaming; Ma, Jun; Song, Haoran; Sun, Shaofang; Zhang, Zhongxiang; Yang, Tao

    2018-04-15

    Remarkable atrazine degradation in the S(IV) autoxidation process catalyzed by Fe 2+ -Mn 2+ (Fe 2+ /Mn 2+ /sulfite) was demonstrated in this study. Competitive kinetic experiments, alcohol inhibiting methods and electron spin resonance (ESR) experiments proved that sulfur radicals were not the major oxidation species. Mn(III) was demonstrated to be the primary active species in the Fe 2+ /Mn 2+ /sulfite process based on the comparison of oxidation selectivity. Moreover, the inhibiting effect of the Mn(III) hydrolysis and the S(IV) autoxidation in the presence of organic contaminants indicated the existence of three Mn(III) consumption routes in the Fe 2+ /Mn 2+ /sulfite process. The absence of hydroxyl radical and sulfate radical was interpreted by the competitive dynamics method. The oxidation capacity of the Fe 2+ /Mn 2+ /sulfite was independent of the initial pH (4.0-6.0) because the fast decay of S(IV) decreased initial pH below 4.0 rapidly. The rate of ATZ degradation was independent of the dissolved oxygen (DO) because that the major DO consumption process was not the rate determining step during the production of SO 5 •- . Phosphate and bicarbonate were confirmed to have greater inhibitory effects than other environmental factors because of their strong pH buffering capacity and complexing capacity for Fe 3+ . The proposed acetylation degradation pathway of ATZ showed the application of the Fe 2+ /Mn 2+ /sulfite process in the research of contaminants degradation pathways. This work investigated the characteristics of the Fe 2+ /Mn 2+ /sulfite process in the presence of organic contaminants, which might promote the development of Mn(III) oxidation technology. Copyright © 2018. Published by Elsevier Ltd.

  1. Small-scale barriers mitigate desertification processes and enhance plant recruitment in a degraded semiarid grassland

    Science.gov (United States)

    Fick, Stephen E; Decker, Cheryl E.; Duniway, Michael C.; Miller, Mark E.

    2016-01-01

    Anthropogenic desertification is a problem that plagues drylands globally; however, the factors which maintain degraded states are often unclear. In Canyonlands National Park on the Colorado Plateau of southeastern Utah, many degraded grasslands have not recovered structure and function >40 yr after release from livestock grazing pressure, necessitating active restoration. We hypothesized that multiple factors contribute to the persistent degraded state, including lack of seed availability, surficial soil-hydrological properties, and high levels of spatial connectivity (lack of perennial vegetation and other surface structure to retain water, litter, seed, and sediment). In combination with seeding and surface raking treatments, we tested the effect of small barrier structures (“ConMods”) designed to disrupt the loss of litter, seed and sediment in degraded soil patches within the park. Grass establishment was highest when all treatments (structures, seed addition, and soil disturbance) were combined, but only in the second year after installation, following favorable climatic conditions. We suggest that multiple limiting factors were ameliorated by treatments, including seed limitation and microsite availability, seed removal by harvester ants, and stressful abiotic conditions. Higher densities of grass seedlings on the north and east sides of barrier structures following the summer months suggest that structures may have functioned as artificial “nurse-plants”, sheltering seedlings from wind and radiation as well as accumulating wind-blown resources. Barrier structures increased the establishment of both native perennial grasses and exotic annuals, although there were species-specific differences in mortality related to spatial distribution of seedlings within barrier structures. The unique success of all treatments combined, and even then only under favorable climatic conditions and in certain soil patches, highlights that restoration success (and

  2. Determination of Polybutadiene Unsaturation Content in Thermal and Thermo-Oxidative Degradation Processes by NMR

    Directory of Open Access Journals (Sweden)

    Farshid Ziaee

    2013-01-01

    Full Text Available The unsaturation content of various polybutadiene (PBD types of 1,4-cis, 1,4-trans and 1,2-vinyl isomers with different molecular weights was investigated. An important parameter for unsaturation content of polybutadiene would be the determination of olefnic and aliphatic contents for three types of isomers. For this purpose, proton and carbon nuclear magnetic resonance spectroscopy methods were employed for determination of 1,4-cis, 1,4-trans and 1,2-vinyl contents. A change of adjustable parameter of NMR software was made for accurate integrals giving better results. The accuracy in calculation of low molecular weight PBD, surface area of chain end group decreased in aliphatic region. Furthermore, the changing of unsaturation content versus time was considered for 1,2-PBD and 1,4-PBD in thermal degradation conditions at 250°C. NMR results showed that during heating, the unsaturation content decreased for 1,2-PBD and was not changed for 1,4-PBD. In fact, the basic factor responsible for changing of unsaturation content in thermal degradation of PBD may be due to the presence of 1,2-vinyl isomer. Finally, changing in unsaturation content versus time was observed for 1,2-PBD and 1,4-PBD in thermo-oxidative degradation conditions at 100°C. The NMR results showed that at extended time, the unsaturation content decreased for 1,4-PBD and was not changed for 1,2-PBD. Moreover, the basic factor for changes in unsaturation content in thermo-oxidative degradation of PBD is due to the presence of 1,4-cis and 1,4-trans isomers.

  3. Aspects of Degradability and Aging of Natural Rubber Latex Films Obtained by Induced Ionizing Radiation Processes of Latex Vulcanization

    International Nuclear Information System (INIS)

    Parra, D. F.

    2006-01-01

    This study refers to the degradability of NRLF, natural rubber latex films, obtained by ionizing radiation. Three types of NRLF were prepared: irradiated latex, irradiated latex with about 1% of soy lecithin and sulfur-vulcanized latex, by cold vulcanization process. The films were buried in vases of two different kinds of soil: common soil and common soil with earthworm humus. Fast aging tests in laboratory with exposition to ultraviolet rays were done in irradiated latex films and irradiated latex films with soy lecithin. The results obtained after ten months of tests with buried films agree with the results of the fast aging tests, showing singularities of each type of soil and each kind of latex process. It also shows how weather inclemency can induce the films degradation process. The sulfur-vulcanized films were weakly degraded when buried. The films with lecithin and buried in vase with only common soil showed the biggest mass loss, but the films with lecithin buried in vases with common earthworm humus and soil increased their weigh and dimensions due to fungi formation. The irradiated latex films are more degradable then the sulfur-vulcanized films. The irradiated latex film, unlike the sulfur vulcanized film, showed high fungi colonization when buried. We conclude that the irradiated latex films are more easily biodegradable than the sulfur vulcanized latex films. The biodegradability increases with the addition of small amounts of soy lecithin (∼1%). The mechanical resistance of the buried films decreased related to the non-buried ones, proving that the outdoor aging in soil and the presence of fungi in the films can modify the mechanical properties of the irradiated latex owing to the biodegradation

  4. Factors affecting the roles of reactive species in the degradation of micropollutants by the UV/chlorine process.

    Science.gov (United States)

    Wu, Zihao; Guo, Kaiheng; Fang, Jingyun; Yang, Xueqin; Xiao, Hong; Hou, Shaodong; Kong, Xiujuan; Shang, Chii; Yang, Xin; Meng, Fangang; Chen, Liwei

    2017-12-01

    The UV/chlorine process is an emerging advanced oxidation process (AOP) that produces various reactive species, such as hydroxyl radicals (HO) and reactive chlorine species (RCS). The effects of the treatment conditions, such as chlorine dosage and pH, and the water matrix components of natural organic matter (NOM), alkalinity, ammonia and halides, on the kinetics and reactive species in the degradation of four micropollutants, metronidazole (MDZ), nalidixic acid (NDA), diethyltoluamide (DEET) and caffeine (CAF), by the UV/chlorine process were investigated. The degradation of MDZ and CAF was primarily attributable to HO and ClO, respectively, while that of NDA was primarily attributable to both ClO and CO 3 - . HO, Cl and CO 3 - are important for the degradation of DEET. The second-order rate constants for ClO with CAF and CO 3 - with NDA were determined to be 5.1 (±0.2) × 10 7  M -1 s -1 and 1.4 (±0.1) × 10 7  M -1 s -1 , respectively. Increasing chlorine dosage slightly changed the contribution of HO but linearly increased that of ClO to micropollutant degradation. Increasing pH decreased the contribution of either HO or Cl but not that of ClO. Both NOM and bicarbonate decreased the contributions of HO and Cl, whereas NOM but not bicarbonate significantly decreased that of ClO. The contribution of either HO or Cl first rose and then fell as the molar ratio of ammonia to chlorine increased from 0 to 1:1, while that of ClO decreased. The co-presence of high concentrations of Cl - and Br - enhanced the contribution of ClBr - and BrCl. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Computational simulation of coupled material degradation processes for probabilistic lifetime strength of aerospace materials

    Science.gov (United States)

    Boyce, Lola; Bast, Callie C.

    1992-01-01

    The research included ongoing development of methodology that provides probabilistic lifetime strength of aerospace materials via computational simulation. A probabilistic material strength degradation model, in the form of a randomized multifactor interaction equation, is postulated for strength degradation of structural components of aerospace propulsion systems subjected to a number of effects or primative variables. These primative variable may include high temperature, fatigue or creep. In most cases, strength is reduced as a result of the action of a variable. This multifactor interaction strength degradation equation has been randomized and is included in the computer program, PROMISS. Also included in the research is the development of methodology to calibrate the above described constitutive equation using actual experimental materials data together with linear regression of that data, thereby predicting values for the empirical material constraints for each effect or primative variable. This regression methodology is included in the computer program, PROMISC. Actual experimental materials data were obtained from the open literature for materials typically of interest to those studying aerospace propulsion system components. Material data for Inconel 718 was analyzed using the developed methodology.

  6. Kinetic and mechanistic investigations of the degradation of sulfamethazine in heat-activated persulfate oxidation process.

    Science.gov (United States)

    Fan, Yan; Ji, Yuefei; Kong, Deyang; Lu, Junhe; Zhou, Quansuo

    2015-12-30

    Sulfamethazine (SMZ) is widely used in livestock feeding and aquaculture as an antibiotic agent and growth promoter. Widespread occurrence of SMZ in surface water, groundwater, soil and sediment has been reported. In this study, degradation of SMZ by heat-activated persulfate (PS) oxidation was investigated in aqueous solution. Experimental results demonstrated that SMZ degradation followed pseudo-first-order reaction kinetics. The pseudo-first-order rate constant (kobs) was increased markedly with increasing concentration of PS and temperature. Radical scavenging tests revealed that the predominant oxidizing species was SO4·(-) with HO playing a less important role. Aniline moiety in SMZ molecule was confirmed to be the reactive site for SO4·(-) attack by comparison with substructural analogs. Nontarget natural water constituents affected SMZ removal significantly, e.g., Cl(-) and HCO3(-) improved the degradation while fulvic acid reduced it. Reaction products were enriched by solid phase extraction (SPE) and analyzed by liquid chromatography-electrospray ionization-triple quadrupole mass spectrometry (LC-ESI-MS/MS). 6 products derived from sulfonamide S--N bond cleavage, aniline moiety oxidation and Smiles-type rearrangement were identified, and transformation pathways of SMZ oxidation were proposed. Results reveal that heat-activated PS oxidation could be an efficient approach for remediation of water contaminated by SMZ and related sulfonamides. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. DI-(2-ETHYLHEXYL PHTHALATE OXIDATIVE DEGRADATION BY FENTON PROCESS IN SYNTHETIC AND REAL PETROCHEMICAL WASTEWATER

    Directory of Open Access Journals (Sweden)

    R. Esmaeli

    2011-09-01

    Full Text Available Di-(2-Ethylhexyl phthalate (DEHP belongs to the class of phthalate esters and is used as an additive in many products including plastics, paints and inks or as a solvent in industrial formulations. The degradation of DEHP in aqueous solution using oxidative Fenton reaction (H2O2/Fe2+ was carried out in this study. It was found that H2O2 concentration, Fe2+ concentration, and pH were the three main factors that could significantly influence the degradation rates of DEHP. The highest degradation percentage (85.6 % of DEHP was observed within 60 min at pH 3 in H2O2/Fe2+ system. The results of our study suggested that the concentration with 90 mg/L H2O2, 5 mg/L Fe2+, and 20 mg/L DEHP in the solution at pH 3 were the optimal conditions. The optimized reaction parameters were preceded for treatment of real wastewater obtained from a petrochemical plant.

  8. Increased fusiform area activation in schizophrenia during processing of spatial frequency-degraded faces, as revealed by fMRI.

    Science.gov (United States)

    Silverstein, S M; All, S D; Kasi, R; Berten, S; Essex, B; Lathrop, K L; Little, D M

    2010-07-01

    People with schizophrenia demonstrate perceptual organization impairments, and these are thought to contribute to their face processing difficulties. We examined the neural substrates of emotionally neutral face processing in schizophrenia by investigating neural activity under three stimulus conditions: faces characterized by the full spectrum of spatial frequencies, faces with low spatial frequency information removed [high spatial frequency (HSF) condition], and faces with high spatial frequency information removed [low spatial frequency (LSF) condition]. Face perception in the HSF condition is more reliant on local feature processing whereas perception in the LSF condition requires greater reliance on global form processing. Past studies of perceptual organization in schizophrenia indicate that patients perform relatively more poorly with degraded stimuli but also that, when global information is absent, patients may perform better than controls because of their relatively increased ability to initially process individual features. Therefore, we hypothesized that people with schizophrenia (n=14) would demonstrate greater face processing difficulties than controls (n=13) in the LSF condition, whereas they would demonstrate a smaller difference or superior performance in the HSF condition. In a gender-discrimination task, behavioral data indicated high levels of accuracy for both groups, with a trend toward an interaction involving higher patient performance in the HSF condition and poorer patient performance in the LSF condition. Patients demonstrated greater activity in the fusiform gyrus compared to controls in both degraded conditions. These data suggest that impairments in basic integration abilities may be compensated for by relatively increased activity in this region.

  9. Sulfate radical-induced degradation of Acid Orange 7 by a new magnetic composite catalyzed peroxymonosulfate oxidation process

    International Nuclear Information System (INIS)

    Chen, Dan; Ma, Xiaolong; Zhou, Jizhi; Chen, Xi; Qian, Guangren

    2014-01-01

    Graphical abstract: Organic dyes could be absorbed on the surface of the composite or dispersed in the solution. Sulfate radicals (SO 4 · − ) generated by the synergistic reaction between peroxymonosulfate (PMS) and the composite, attacked the organic functional groups of the dyes molecules both adsorbed on the composite surface and dispersed in the solution, which resulted in the degradation of AO7 dye. - Highlights: • A new composite was synthesized successfully via microwave hydrothermal method. • The complete degradation in the system of FLCN and PMS can be achieved. • The catalytic behavior of FLCN can be reused at least for five times. • The AO7 degradation mechanism in the system of FLCN and PMS was demonstrated. - Abstract: We synthesized a novel magnetic composite, Fe 3 O 4 /Cu(Ni)Cr-LDH, as a heterogeneous catalyst for the degradation of organic dyes in the solution using sulfate radical-based advanced oxidation processes. The physicochemical properties of the composite synthesized via two-step microwave hydrothermal method were characterized by several techniques, such as X-ray diffraction (XRD), inductively coupled plasma (ICP), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The degradation tests were performed at 25 °C with Acid Orange 7 (AO7) initial concentration of 25 mg/L and AO7/peroxymonosulfate (PMS) molar ratio of 1:10, which showed that the complete degradation by Fe 3 O 4 /Cu 1.5 Ni 0.5 Cr-LDH could be achieved and the mineralization rate could reach 46%. PMS was activated by Cu (II) and Fe (II/III) of Fe 3 O 4 /Cu(Ni)Cr-LDH to generate sulfate radicals (SO 4 · − ). Subsequently, the organic functional groups of AO7 molecules were destroyed by sulfate radicals (SO 4 · − ), inducing the degradation of AO7. Moreover, the catalytic behavior of the catalysts could be reused five times. Therefore, our work suggested that the Fe 3 O 4 /Cu(Ni)Cr-LDH composite could be applied widely for the

  10. Kinetics and energy efficiency for the degradation of 1,4-dioxane by electro-peroxone process

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huijiao; Bakheet, Belal; Yuan, Shi; Li, Xiang; Yu, Gang [School of Environment, Tsinghua University, Beijing 100084 (China); Murayama, Seiichi [Power and Industrial Systems R& D Center, Toshiba Corporation, Fuchu-shi, Tokyo (Japan); Wang, Yujue, E-mail: wangyujue@tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-08-30

    Highlights: • E-peroxone couples electrolysis with ozonation to driven peroxone reaction for pollutant degradation. • Significant amounts of ·OH can be efficiently produced in the E-peroxone process. • E-peroxone greatly enhances 1,4-dioxane degradation kinetics compared with ozonation and electrolysis. • E-peroxone consumes less energy for 1,4-dioxane mineralization than ozonation and electrolysis. • E-peroxone offers a cost-effective and energy-efficient alternative to degrade 1,4-dioxane. - Abstract: Degradation of 1,4-dioxane by ozonation, electrolysis, and their combined electro-peroxone (E-peroxone) process was investigated. The E-peroxone process used a carbon-polytetrafluorethylene cathode to electrocatalytically convert O{sub 2} in the sparged ozone generator effluent (O{sub 2} and O{sub 3} gas mixture) to H{sub 2}O{sub 2}. The electro-generated H{sub 2}O{sub 2} then react with sparged O{sub 3} to yield aqueous ·OH, which can in turn oxidize pollutants rapidly in the bulk solution. Using p-chlorobenzoic acid as ·OH probe, the pseudo-steady concentration of ·OH was determined to be ∼0.744 × 10{sup −9} mM in the E-peroxone process, which is approximately 10 and 186 times of that in ozonation and electrolysis using a Pt anode. Thanks to its higher ·OH concentration, the E-peroxone process eliminated 96.6% total organic carbon (TOC) from a 1,4-dioxane solution after 2 h treatment with a specific energy consumption (SEC) of 0.376 kWh g{sup −1} TOC{sub removed}. In comparison, ozonation and electrolysis using a boron-doped diamond anode removed only ∼6.1% and 26.9% TOC with SEC of 2.43 and 0.558 kWh g{sup −1} TOC{sub removed}, respectively. The results indicate that the E-peroxone process can significantly improve the kinetics and energy efficiency for 1,4-dioxane mineralization as compared to the two individual processes. The E-peroxone process may thus offer a highly effective and energy-efficient alternative to treat 1,4-dioxane

  11. Application of residual polysaccharide-degrading enzymes in dried shiitake mushrooms as an enzyme preparation in food processing.

    Science.gov (United States)

    Tatsumi, E; Konishi, Y; Tsujiyama, S

    2016-11-01

    To examine the activities of residual enzymes in dried shiitake mushrooms, which are a traditional foodstuff in Japanese cuisine, for possible applications in food processing. Polysaccharide-degrading enzymes remained intact in dried shiitake mushrooms and the activities of amylase, β-glucosidase and pectinase were high. A potato digestion was tested using dried shiitake powder. The enzymes reacted with potato tuber specimens to solubilize sugars even under a heterogeneous solid-state condition and that their reaction modes were different at 38 and 50 °C. Dried shiitake mushrooms have a potential use in food processing as an enzyme preparation.

  12. Modeling Aerobic Carbon Source Degradation Processes using Titrimetric Data and Combined Respirometric-Titrimetric Data: Structural and Practical Identifiability

    DEFF Research Database (Denmark)

    Gernaey, Krist; Petersen, B.; Dochain, D.

    2002-01-01

    The structural and practical identifiability of a model for description of respirometric-titrimetric data derived from aerobic batch substrate degradation experiments of a CxHyOz carbon source with activated sludge was evaluated. The model processes needed to describe titrimetric data included su...... the initial substrate concentration S-S(O) is known. The values found correspond to values reported in literature, but, interestingly, also seem able to reflect the occurrence of storage processes when pulses of acetate and dextrose are added. (C) 2002 Wiley Periodicals, Inc....

  13. COMPARATIVE ANALYSIS USING DIPIRONA DEGRADATION PROCESS WITH PHOTO-FENTON UV-C LIGHT AND SOLAR RADIATION

    Directory of Open Access Journals (Sweden)

    Daniella Carla Napoleão

    2015-01-01

    Full Text Available The contamination of water bodies is a major concern on the part of scientists from different parts of the world. Domestic and industrial activities are the cause of the daily pouring of various types of pollutants which are in most cases resistant to conventional treatments of waters. Among the contaminants, especially noteworthy are the drugs in which it is found that 50% to 90% are discarded without treatment. The concerns about these substances are the adverse effects to human health and animals, especially in aquatic environments. The advanced oxidation processes (AOP have been studied and applied as an efficient alternative treatment, in order that it can be applied to the degradation of the different pollutants, considering that can generate hydroxyl radicals, highly reactive even somewhat selective. This study evaluated the efficiency of the photo-Fenton process using UV-C radiation and sunlight to degradation of the drug dipyrone in aqueous solution contaminated with the active ingredient of the drug at a concentration of 20 mg.L-1. Assays were performed with 50 mL aliquots of the solution following 23 factorial designs with central point, and the variables studied: addition of H2O2, adding FeSO4.7H2O and time. The detection and quantification of dipyrone before and after the AOP was performed by high performance liquid chromatography (HPLC and verified that about DE100% degradation of the compound was obtained.

  14. Photo-stability study of a solution-processed small molecule solar cell system: correlation between molecular conformation and degradation.

    Science.gov (United States)

    Newman, Michael J; Speller, Emily M; Barbé, Jérémy; Luke, Joel; Li, Meng; Li, Zhe; Wang, Zhao-Kui; Jain, Sagar M; Kim, Ji-Seon; Lee, Harrison Ka Hin; Tsoi, Wing Chung

    2018-01-01

    Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-processed SMSC using benzodithiophene terthiophene rhodamine:[6,6]-phenyl C 71 butyric acid methyl ester (BTR:PC 71 BM) with increasing solvent vapour annealing time applied to the active layer, controlling the crystallisation of the BTR phase. We find that the burn-in behaviour is strongly correlated to the crystallinity of BTR. To look at the possible degradation mechanisms, we studied the fresh and photo-aged blend films with grazing incidence X-ray diffraction, UV-vis absorbance, Raman spectroscopy and photoluminescence (PL) spectroscopy. Although the crystallinity of BTR affects the performance drop during the burn-in period, the degradation is found not to originate from the crystallinity changes of the BTR phase, but correlates with changes in molecular conformation - rotation of the thiophene side chains, as resolved by Raman spectroscopy which could be correlated to slight photobleaching and changes in PL spectra.

  15. Self-bioremediation of cork-processing wastewaters by (chloro)phenol-degrading bacteria immobilised onto residual cork particles.

    Science.gov (United States)

    del Castillo, I; Hernández, P; Lafuente, A; Rodríguez-Llorente, I D; Caviedes, M A; Pajuelo, E

    2012-04-15

    Cork manufacturing is a traditional industry in Southern Europe, being the main application of this natural product in wine stoppers and insulation. Cork processing begins at boiling the raw material. As a consequence, great volumes of dark wastewaters, with elevated concentrations of chlorophenols, are generated, which must be depurated through costly physicochemical procedures before discarding them into public water courses. This work explores the potential of bacteria, isolated from cork-boiling waters storage ponds, in bioremediation of the same effluent. The bacterial population present in cork-processing wastewaters was analysed by DGGE; low bacterial biodiversity was found. Aerobic bacteria were isolated and investigated for their tolerance against phenol and two chlorophenols. The most tolerant strains were identified by sequencing 16S rDNA. The phenol-degrading capacity was investigated by determining enzyme activities of the phenol-degrading pathway. Moreover, the capacity to form biofilms was analysed in a microtitre plate assay. Finally, the capacity to form biofilms onto the surface of residual small cork particles was evaluated by acridine staining followed by epifluorescence microscopy and by SEM. A low-cost bioremediation system, using phenol-degrading bacteria immobilised onto residual cork particles (a by-product of the industry) is proposed for the remediation of this industrial effluent (self-bioremediation). Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Solution processable RGO-CdZnS composite for solar light responsive photocatalytic degradation of 4-Nitrophenol

    Science.gov (United States)

    Ibrahim, Sk; Chakraborty, Koushik; Pal, Tanusri; Ghosh, Surajit

    2017-05-01

    We report the one pot single step synthesis and characterization of solution processable reduced graphene oxide (RGO) - cadmium zinc sulfide (CdZnS) nanocomposite materials. The composite was characterized structurally and morphologically by XRD and TEM studies. The reduction of GO in RGO-CdZnS composite, was confirmed by XPS and Raman spectroscopy. The photocatalytic activity of the RGO-CdZnS composite was investigated towards the degradation of 4-Nitrophenol. A notable increase of photocatalytic efficiency of RGO-CdZnS compare to controlled CdZnS was observed. Here RGO plays a crucial role to efficient photo induced charge separation from the CdZnS, and decreases the electron-hole recombination probability and subsequently enhanced the photocatalytic activity of the RGO-CdZnS composite material under simulated solar light irradiation. This work highlights the potential application of RGO-based materials in the field of photocatalytic degradation of organic water pollutant.

  17. Enhancement of oxygen diffusion process on a rotating disk electrode for the electro-Fenton degradation of tetracycline

    International Nuclear Information System (INIS)

    Zhang, Yan; Gao, Ming-Ming; Wang, Xin-Hua; Wang, Shu-Guang; Liu, Rui-Ting

    2015-01-01

    An electro-Fenton process was developed for wastewater treatment in which hydrogen peroxide was generated in situ with a rotating graphite disk electrode as cathode. The maximum H 2 O 2 generation rate for the RDE reached 0.90 mg/L/h/cm 2 under the rotation speed of 400 rpm at pH 3, and −0.8 V vs SCE. The performance of this electro-Fenton reactor was assessed by tetracycline degradation in an aqueous solution. Experimental results showed the rotation of disk cathode resulted in the efficient production of H 2 O 2 without oxygen aeration, and excellent ability for degrading organic pollutants compared to the electro-Fenton system with fixed cathode. Tetracycline of 50 mg/L was degraded completely within 2 h with the addition of ferrous ion (1.0 mM). The chronoamperometry analysis was employed to investigate the oxygen diffusion on the rotating cathode. The results demonstrated that the diffusion coefficients of dissolved oxygen is 19.45 × 10 −5 cm 2 /s, which is greater than that reported in the literature. Further calculation indicated that oxygen is able to diffuse through the film on the rotating cathode within the contact time in each circle. This study proves that enhancement of oxygen diffusion on RDE is benefit for H 2 O 2 generation, thus provides a promising method for organic pollutants degradation by the combination of RDE with electro-Fenton reactor and offers a new insight on the oxygen transform process in this new system.

  18. Modelling of degradation processes in creep resistant steels through accelerated creep tests after long-term isothermal ageing

    Energy Technology Data Exchange (ETDEWEB)

    Sklenicka, V.; Kucharova, K.; Svoboda, M.; Kroupa, A.; Kloc, L. [Academy of Sciences of the Czech Republic, Brno (Czech Republic). Inst. of Physics of Materials; Cmakal, J. [UJP PRAHA a.s., Praha-Zbraslav (Czech Republic)

    2010-07-01

    Creep behaviour and degradation of creep properties of creep resistant materials are phenomena of major practical relevance, often limiting the lives of components and structures designed to operate for long periods under stress at elevated and/or high temperatures. Since life expectancy is, in reality, based on the ability of the material to retain its high-temperature creep strength for the projected designed life, methods of creep properties assessment based on microstructural evolution in the material during creep rather than simple parametric extrapolation of short-term creep tests are necessary. In this paper we will try to further clarify the creep-strength degradation of selected advanced creep resistant steels. In order to accelerate some microstructural changes and thus to simulate degradation processes in long-term service, isothermal ageing at 650 C for 10 000 h was applied to P91 and P23 steels in their as-received states. The accelerated tensile creep tests were performed at temperature 600 C in argon atmosphere on all steels both in the as-received state and after long-term isothermal ageing, in an effort to obtain a more complete description of the role of microstructural stability in high temperature creep of these steels. Creep tests were followed by microstructural investigations by means of both transmission and scanning electron microscopy and by the thermodynamic calculations. The applicability of the accelerated creep tests was verified by the theoretical modelling of the phase equilibria at different temperatures. It is suggested that under restructed oxidation due to argon atmosphere microstructural instability is the main detrimental process in the long-term degradation of the creep rupture strength of these steels. (orig.)

  19. Impact of compost process conditions on organic micro pollutant degradation during full scale composting.

    Science.gov (United States)

    Sadef, Yumna; Poulsen, Tjalfe Gorm; Bester, Kai

    2015-06-01

    Knowledge about the effects of oxygen concentration, nutrient availability and moisture content on removal of organic micro-pollutants during aerobic composting is at present very limited. Impact of oxygen concentration, readily available nitrogen content (NH4(+), NO3(-)), and moisture content on biological transformation of 15 key organic micro-pollutants during composting, was therefore investigated using bench-scale degradation experiments based on non-sterile compost samples, collected at full-scale composting facilities. In addition, the adequacy of bench-scale composting experiments for representing full-scale composting conditions, was investigated using micro-pollutant concentration measurements from both bench- and full-scale composting experiments. Results showed that lack of oxygen generally prevented transformation of organic micro-pollutants. Increasing readily available nitrogen content from about 50 mg N per 100 g compost to about 140 mg N per 100 g compost actually reduced micro-pollutant transformation, while changes in compost moisture content from 50% to 20% by weight, only had minor influence on micro-pollutant transformation. First-order micro-pollutant degradation rates for 13 organic micro-pollutants were calculated using data from both full- and bench-scale experiments. First-order degradation coefficients for both types of experiments were similar and ranged from 0.02 to 0.03 d(-1) on average, indicating that if a proper sampling strategy is employed, bench-scale experiments can be used to represent full-scale composting conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. A Miniature Membrane Reactor for Evaluation of Process Design Options on the Enzymatic Degradation of Pectin

    DEFF Research Database (Denmark)

    Zainal Alam, Muhd Nazrul Hisham; Pinelo, Manuel; Arnous, Anis

    2011-01-01

    was fabricated from poly(methylmethacrylate) (PMMA) and poly(dimethylsiloxane) (PDMS) with a working volume of ∼190 μL. The prototype also contained the necessary sensors and actuators, i.e., pressure transducer, mixing via magnetic stirrer bar and a temperature controller. The functionality of the prototype...... was demonstrated by performing a continuous enzymatic degradation of pectin experiment for a range of reactor conditions: different membrane molecular weight cutoff (MWCO) values, enzyme-to-substrate ratios (E/S), and substrate feeding rates (F) were assessed. Based on the experimental data, it was found...

  1. Enhanced heterogeneous photo-Fenton process modified by magnetite and EDDS: BPA degradation.

    Science.gov (United States)

    Huang, Wenyu; Luo, Mengqi; Wei, Chaoshuai; Wang, Yinghui; Hanna, Khalil; Mailhot, Gilles

    2017-04-01

    In this research, magnetite and ethylenediamine-N,N'-disuccinic acid (EDDS) are used in a heterogeneous photo-Fenton system in order to find a new way to remove organic contaminants from water. Influence of different parameters including magnetite dosage, EDDS concentration, H 2 O 2 concentration, and pH value were evaluated. The effect of different radical species including HO · and HO 2 · /O 2 ·- was investigated by addition of different scavengers into the system. The addition of EDDS improved the heterogeneous photo-Fenton degradation of bisphenol A (BPA) through the formation of photochemically efficient Fe-EDDS complex. This effect is dependent on the H 2 O 2 and EDDS concentrations and pH value. The high performance observed at pH 6.2 could be explained by the ability of O 2 ·- to generate Fe(II) from Fe(III) species reduction. GC-MS analysis suggested that the cleavage of the two benzene rings is the first degradation step followed by oxidation leading to the formation of the benzene derivatives. Then, the benzene ring was opened due to the attack of HO · radicals producing short-chain organic compounds of low molecular weight like glycerol and ethylene glycol. These findings regarding the capability of EDDS/magnetite system to promote heterogeneous photo-Fenton oxidation have important practical implications for water treatment technologies.

  2. Use of ZnO:Mn particles for degradation of methylene blue by photocatalysis process

    International Nuclear Information System (INIS)

    Giraldi, T. R.; Swerts, J. P.; Vicente, M. A.; Paris, E.C.; Ribeiro, C.

    2016-01-01

    The management of water use in the agricultural environment is a key factor to build new environmentally sustainable productive methods. Photocatalysis is a promising method for water decontamination. This research paper aimed to evaluate the photocatalytic potential of pure and Mn-doped ZnO particles. The materials were obtained by the polymeric precursor method, and characterized by X-ray diffraction, N_2 adsorption in low temperature, infrared and ultraviolet spectroscopy, and photoluminescence. In order to evaluate ZnO:Mn particles photo efficiency, experiments were carried out by applying the methylene blue dye solution to photodegradation under UVC exposure. The particles had ZnO single-phase, but low specific surface area. The sample ZnO:0.25% Mn presented higher efficiency in the methylene blue photocatalytic degradation test. This efficiency was related to a higher band gap energy value and a lower rate of electron recombination, which allows greater formation of hydroxyl radicals, which are responsible for dye degradation. (author)

  3. Fundamental study of hydrogen-attachment-induced peptide fragmentation occurring in the gas phase and during the matrix-assisted laser desorption/ionization process.

    Science.gov (United States)

    Asakawa, Daiki; Takahashi, Hidenori; Iwamoto, Shinichi; Tanaka, Koichi

    2018-05-09

    Mass spectrometry with hydrogen-radical-mediated fragmentation techniques has been used for the sequencing of proteins/peptides. The two methods, matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) and hydrogen attachment/abstraction dissociation (HAD) are known as hydrogen-radical-mediated fragmentation techniques. MALDI-ISD occurs during laser induced desorption processes, whereas HAD utilizes the association of hydrogen with peptide ions in the gas phase. In this study, the general mechanisms of MALDI-ISD and HAD of peptides were investigated. We demonstrated the fragmentation of four model peptides and investigated the fragment formation pathways using density functional theory (DFT) calculations. The current experimental and computational joint study indicated that MALDI-ISD and HAD produce aminoketyl radical intermediates, which immediately undergo radical-induced cleavage at the N-Cα bond located on the C-terminal side of the radical site, leading to the c'/z˙ fragment pair. In the case of MALDI-ISD, the z˙ fragments undergo a subsequent reaction with the matrix to give z' and matrix adducts of the z fragments. In contrast, the c' and z˙ fragments react with hydrogen atoms during the HAD processes, and various fragment species, such as c˙, c', z˙ and z', were observed in the HAD-MS/MS mass spectra.

  4. Determination of degradation products and process related impurities of asenapine maleate in asenapine sublingual tablets by UPLC

    Science.gov (United States)

    Kumar, Nitin; Sangeetha, D.; Kalyanraman, L.

    2017-11-01

    For determination of process related impurities and degradation products of asenapine maleate in asenapine sublingual Tablets, a reversed phase, stability indicating UPLC method was developed. Acetonitrile, methanol and potassium dihydrogen phosphate buffer with tetra-n- butyl ammonium hydrogen sulphate as ion pair (pH 2.2; 0.01 M) at flow rate of 0.2 ml/min were used in gradient elution mode. Separation was achieved by using acquity BEH Shield RP18 column (1.7 μm, 2.1 mm×100 mm) at 35 ºC. UV detection was performed at 228 nm. Subsequently the liquid chromatography method was validated as per ICH. The drug product was exposed to the stress conditions of acid hydrolysis, base hydrolysis, water hydrolysis, oxidative, thermal, and photolytic. In oxidative stress and thermal stress significant degradation was observed. All the degradation products were well separated from analyte peak and its impurities. Stability indicating nature of the method was proved by demonstrating the peak purity of Asenapine peak in all the stressed samples. The mass balance was found >95% for all the stress conditions. Based on method validation, the method was found specific, linear, accurate, precise, rugged and robust.

  5. Circadian Clock Synchronization of the Cell Cycle in Zebrafish Occurs through a Gating Mechanism Rather Than a Period-phase Locking Process.

    Science.gov (United States)

    Laranjeiro, Ricardo; Tamai, T Katherine; Letton, William; Hamilton, Noémie; Whitmore, David

    2018-04-01

    Studies from a number of model systems have shown that the circadian clock controls expression of key cell cycle checkpoints, thus providing permissive or inhibitory windows in which specific cell cycle events can occur. However, a major question remains: Is the clock actually regulating the cell cycle through such a gating mechanism or, alternatively, is there a coupling process that controls the speed of cell cycle progression? Using our light-responsive zebrafish cell lines, we address this issue directly by synchronizing the cell cycle in culture simply by changing the entraining light-dark (LD) cycle in the incubator without the need for pharmacological intervention. Our results show that the cell cycle rapidly reentrains to a shifted LD cycle within 36 h, with changes in p21 expression and subsequent S phase timing occurring within the first few hours of resetting. Reentrainment of mitosis appears to lag S phase resetting by 1 circadian cycle. The range of entrainment of the zebrafish clock to differing LD cycles is large, from 16 to 32 hour periods. We exploited this feature to explore cell cycle entrainment at both the population and single cell levels. At the population level, cell cycle length is shortened or lengthened under corresponding T-cycles, suggesting that a 1:1 coupling mechanism is capable of either speeding up or slowing down the cell cycle. However, analysis at the single cell level reveals that this, in fact, is not true and that a gating mechanism is the fundamental method of timed cell cycle regulation in zebrafish. Cell cycle length at the single cell level is virtually unaltered with varying T-cycles.

  6. Degradation alternatives for a commercial fungicide in water: biological, photo-Fenton, and coupled biological photo-Fenton processes.

    Science.gov (United States)

    López-Loveira, Elsa; Ariganello, Federico; Medina, María Sara; Centrón, Daniela; Candal, Roberto; Curutchet, Gustavo

    2017-11-01

    Imazalil (IMZ) is a widely used fungicide for the post-harvest treatment of citrus, classified as "likely to be carcinogenic in humans" for EPA, that can be only partially removed by conventional biological treatment. Consequently, specific or combined processes should be applied to prevent its release to the environment. Biological treatment with adapted microorganism consortium, photo-Fenton, and coupled biological photo-Fenton processes were tested as alternatives for the purification of water containing high concentration of the fungicide and the coadjutants present in the commercial formulation. IMZ-resistant consortium with the capacity to degrade IMZ in the presence of a C-rich co-substrate was isolated from sludge coming from a fruit packaging company wastewater treatment plant. This consortium was adapted to resist and degrade the organics present in photo-Fenton-oxidized IMZ water solution. Bacteria colonies from the consortia were isolated and identified. The effect of H 2 O 2 initial concentration and dosage on IMZ degradation rate, average oxidation state (AOS), organic acid concentration, oxidation, and mineralization percentage after photo-Fenton process was determined. The application of biological treatment to the oxidized solutions notably decreased the total organic carbon (TOC) in solution. The effect of the oxidation degree, limited by H 2 O 2 concentration and dosage, on the percentage of mineralization obtained after the biological treatment was determined and explained in terms of changes in AOS. The concentration of H 2 O 2 necessary to eliminate IMZ by photo-Fenton and to reduce TOC and chemical oxygen demand (COD) by biological treatment, in order to allow the release of the effluents to rivers with different flows, was estimated.

  7. Evaluation and Control of Mechanical Degradation of Austenitic Stainless 310S Steel Substrate During Coated Superconductor Processing

    Science.gov (United States)

    Kim, Seung-Gyu; Kim, Najung; Shim, Hyung-Seok; Kwon, Oh Min; Kwon, Dongil

    2018-05-01

    The superconductor industry considers cold-rolled austenitic stainless 310S steel a less expensive substitute for Hastelloy X as a substrate for coated superconductor. However, the mechanical properties of cold-rolled 310S substrate degrade significantly in the superconductor deposition process. To overcome this, we applied hot rolling at 900 °C (or 1000 °C) to the 310S substrate. To check the property changes, a simulated annealing condition equivalent to that used in manufacturing was determined and applied. The effects of the hot rolling on the substrate were evaluated by analyzing its physical properties and texture.

  8. Fermented liquid feed - Feed processing has a big impact on microbial degradation of free lysine during fermentation

    DEFF Research Database (Denmark)

    Canibe, Nuria; Jensen, Bent Borg

    2010-01-01

    In order to investigate the influence of feed processing on the microbial degradation of free lysine during fermentation of liquid feed, a study at laboratory scale was carried out. Based on a standard Danish grower diet with extra free amino acids added, two treatments were prepared: treatment 1...... a few hours of fermentation, the levels in both treatments became similar. The concentration of acetic acid was higher in the mixture containing the mash feed than in that containing the pelleted feed. The disappearance of free lysine was much higher when mash feed was fermented than when the same...

  9. Degradation and ecotoxicity of dye Reactive Black 5 after reductive-oxidative process : Environmental Science and Pollution Research.

    Science.gov (United States)

    Cuervo Lumbaque, Elisabeth; Gomes, Monike Felipe; Da Silva Carvalho, Vanessa; de Freitas, Adriane Martins; Tiburtius, Elaine Regina Lopes

    2017-03-01

    This research paper describes the study of a reduction-oxidation system using commercial steel wool (Fe 0 ) and H 2 O 2 for degradation of the dye Reactive Black 5 and aromatic compounds in water. The reductive process alone allowed the almost complete removal of color (97 ± 1 %) after 60 min of reaction. The decrease in spectral area (λ = 599 nm) associated with the chromophore group indicates breakage of the azo bonds. Moreover, the significant change in UV spectra can be associated with the formation of aromatic amines. Regarding the transformation products, a spectrophotometric method based on the diazotization reaction was employed to identify aromatic amines after reductive process, using sulfanilic acid as a model of aromatic amines. In addition, association with Fenton reagents improved the efficiency in the system with 93 ± 1 % degradation of intermediates formed during the reductive process. Ecotoxicological analysis revealed that the dye solution, after the reductive and oxidative processes, was not toxic to Lactuca sativa seeds. For Daphnia magna, the EC 50 (%) values observed revealed that dye solution has an EC 50 (%) = 74.1 and after reductive process, the toxicity increased (EC 50 (%) = 63.5), which might be related to the formation of aromatic amines. However, after the Fenton process, the EC 50 (%) was >100. These results demonstrated that the Fenton reaction using steel wool as an iron source was very efficient to decrease color, aromatic transformation products, and the ecotoxicity of Reactive Black 5 in solution.

  10. Distortion of genetically modified organism quantification in processed foods: influence of particle size compositions and heat-induced DNA degradation.

    Science.gov (United States)

    Moreano, Francisco; Busch, Ulrich; Engel, Karl-Heinz

    2005-12-28

    Milling fractions from conventional and transgenic corn were prepared at laboratory scale and used to study the influence of sample composition and heat-induced DNA degradation on the relative quantification of genetically modified organisms (GMO) in food products. Particle size distributions of the obtained fractions (coarse grits, regular grits, meal, and flour) were characterized using a laser diffraction system. The application of two DNA isolation protocols revealed a strong correlation between the degree of comminution of the milling fractions and the DNA yield in the extracts. Mixtures of milling fractions from conventional and transgenic material (1%) were prepared and analyzed via real-time polymerase chain reaction. Accurate quantification of the adjusted GMO content was only possible in mixtures containing conventional and transgenic material in the form of analogous milling fractions, whereas mixtures of fractions exhibiting different particle size distributions delivered significantly over- and underestimated GMO contents depending on their compositions. The process of heat-induced nucleic acid degradation was followed by applying two established quantitative assays showing differences between the lengths of the recombinant and reference target sequences (A, deltal(A) = -25 bp; B, deltal(B) = +16 bp; values related to the amplicon length of the reference gene). Data obtained by the application of method A resulted in underestimated recoveries of GMO contents in the samples of heat-treated products, reflecting the favored degradation of the longer target sequence used for the detection of the transgene. In contrast, data yielded by the application of method B resulted in increasingly overestimated recoveries of GMO contents. The results show how commonly used food technological processes may lead to distortions in the results of quantitative GMO analyses.

  11. Passive sampling of DDT, DDE and DDD in sediments: accounting for degradation processes with reaction-diffusion modeling.

    Science.gov (United States)

    Tcaciuc, A Patricia; Borrelli, Raffaella; Zaninetta, Luciano M; Gschwend, Philip M

    2018-01-24

    Passive sampling is becoming a widely used tool for assessing freely dissolved concentrations of hydrophobic organic contaminants in environmental media. For certain media and target analytes, the time to reach equilibrium exceeds the deployment time, and in such cases, the loss of performance reference compounds (PRCs), loaded in the sampler before deployment, is one of the common ways used to assess the fractional equilibration of target analytes. The key assumption behind the use of PRCs is that their release is solely diffusion driven. But in this work, we show that PRC transformations in the sediment can have a measurable impact on the PRC releases and even allow estimation of that compound's transformation rate in the environment of interest. We found that in both field and lab incubations, the loss of the 13 C 2,4'-DDT PRC from a polyethylene (PE) passive sampler deployed at the sediment-water interface was accelerated compared to the loss of other PRCs ( 13 C-labeled PCBs, 13 C-labeled DDE and DDD). The DDT PRC loss was also accompanied by accumulation in the PE of its degradation product, 13 C 2,4'-DDD. Using a 1D reaction-diffusion model, we deduced the in situ degradation rates of DDT from the measured PRC loss. The in situ degradation rates increased with depth into the sediment bed (0.14 d -1 at 0-10 cm and 1.4 d -1 at 30-40 cm) and although they could not be independently validated, these rates compared favorably with literature values. This work shows that passive sampling users should be cautious when choosing PRCs, as degradation processes can affect some PRC's releases from the passive sampler. More importantly, this work opens up the opportunity for novel applications of passive samplers, particularly with regard to investigating in situ degradation rates, pathways, and products for both legacy and emerging contaminants. However, further work is needed to confirm that the rates deduced from model fitting of PRC loss are a true reflection of DDT

  12. Prevenient dye-degradation mechanisms using UV/TiO{sub 2}/carbon nanotubes process

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, C.-Y. [Department of Safety Health and Environmental Engineering, National Yunlin University of Science and Technology, 123, Section 3, University Road, Douliu, Yunlin, Taiwan (China)], E-mail: kuocyr@ms35.hinet.net

    2009-04-15

    Photocatalysis research heavily emphasizes increasing photo-efficiency. This study presents the application of carbon nanotubes (CNTs) to increase the photocatalytic activity of TiO{sub 2}. It elucidates the effect of CNTs dose on the decolorization efficiency of aqueous azo dye, C.I. Reactive Red 2 (RR2), determines the effects of SO{sub 4}{sup 2-} formation and removal of total organic carbon (TOC), and measures the effects of various ultraviolet wavelengths. Scanning electron microscopy was used to elucidate the mixing phenomenon and the size of TiO{sub 2} and CNTs; X-ray diffraction was used to determine crystallinity; a BET meter was used to measure surface area and a spectrophotometry was used to determine the decolorization of RR2. Experimental results indicated significant effects of photodegradation on the combination of TiO{sub 2} with CNTs and electron transfer is higher for 410 nm irradiation than for 365 nm, revealing that solar light can be used. The electron transfer in the TiO{sub 2}/CNTs composites reduced the electron/hole recombination and increased the photon efficiency and the prevenient dye-degradation mechanisms using UV/TiO{sub 2}/CNTs were established.

  13. Fundamental processes governing operation and degradation in state of the art P-OLEDs

    Science.gov (United States)

    Roberts, Matthew; Asada, Kohei; Cass, Michael; Coward, Chris; King, Simon; Lee, Andrew; Pintani, Martina; Ramon, Miguel; Foden, Clare

    2010-05-01

    We present a theoretical and experimental analysis of operation and degradation of model fluorescent blue bilayer polymer organic light emitting diodes (P-OLED). Optical and electrical simulations of bilayer P-OLEDs are used to highlight the key material and device parameters required for efficient recombination and outcoupling of excitons. Mobility data for a model interlayer material poly (9,9-dioctylfluorene-N-(4-(2-butyl)phenyl)-diphenylamine) (TFB) and a model fluorescent blue light emitting material poly-(9,9'- dioctylfluorene-co-bis-N, N'-(4-butylphenyl)-bis-N,N'- phenyl-1,4-phenylenediamine) (95:5 mol%) (F8-PFB random copoloymer), is shown to satisfy the key charge transport characteristics required to ensure exciton formation at the optimum location for efficient extraction of the light where μh (LEP) 90%) of the quenching sites produced. This highlights the importance of understanding these reversible phenomena in improving P-OLED lifetime and commercial adoption of the technology.

  14. ER-associated degradation is required for vasopressin prohormone processing and systemic water homeostasis

    Science.gov (United States)

    Somlo, Diane R.M.; Kim, Geun Hyang; Prescianotto-Baschong, Cristina; Sun, Shengyi; Beuret, Nicole; Long, Qiaoming; Rutishauser, Jonas

    2017-01-01

    Peptide hormones are crucial regulators of many aspects of human physiology. Mutations that alter these signaling peptides are associated with physiological imbalances that underlie diseases. However, the conformational maturation of peptide hormone precursors (prohormones) in the ER remains largely unexplored. Here, we report that conformational maturation of proAVP, the precursor for the antidiuretic hormone arginine-vasopressin, within the ER requires the ER-associated degradation (ERAD) activity of the Sel1L-Hrd1 protein complex. Serum hyperosmolality induces expression of both ERAD components and proAVP in AVP-producing neurons. Mice with global or AVP neuron–specific ablation of Se1L-Hrd1 ERAD progressively developed polyuria and polydipsia, characteristics of diabetes insipidus. Mechanistically, we found that ERAD deficiency causes marked ER retention and aggregation of a large proportion of all proAVP protein. Further, we show that proAVP is an endogenous substrate of Sel1L-Hrd1 ERAD. The inability to clear misfolded proAVP with highly reactive cysteine thiols in the absence of Sel1L-Hrd1 ERAD causes proAVP to accumulate and participate in inappropriate intermolecular disulfide–bonded aggregates, promoted by the enzymatic activity of protein disulfide isomerase (PDI). This study highlights a pathway linking ERAD to prohormone conformational maturation in neuroendocrine cells, expanding the role of ERAD in providing a conducive ER environment for nascent proteins to reach proper conformation. PMID:28920920

  15. Unraveling micro- and nanoscale degradation processes during operation of high-temperature polymer-electrolyte-membrane fuel cells

    Science.gov (United States)

    Hengge, K.; Heinzl, C.; Perchthaler, M.; Varley, D.; Lochner, T.; Scheu, C.

    2017-10-01

    The work in hand presents an electron microscopy based in-depth study of micro- and nanoscale degradation processes that take place during the operation of high-temperature polymer-electrolyte-membrane fuel cells (HT-PEMFCs). Carbon supported Pt particles were used as cathodic catalyst material and the bimetallic, carbon supported Pt/Ru system was applied as anode. As membrane, cross-linked polybenzimidazole was used. Scanning electron microscopy analysis of cross-sections of as-prepared and long-term operated membrane-electrode-assemblies revealed insight into micrometer scale degradation processes: operation-caused catalyst redistribution and thinning of the membrane and electrodes. Transmission electron microscopy investigations were performed to unravel the nanometer scale phenomena: a band of Pt and Pt/Ru nanoparticles was detected in the membrane adjacent to the cathode catalyst layer. Quantification of the elemental composition of several individual nanoparticles and the overall band area revealed that they stem from both anode and cathode catalyst layers. The results presented do not demonstrate any catastrophic failure but rather intermediate states during fuel cell operation and indications to proceed with targeted HT-PEMFC optimization.

  16. Study on Handing Process and Quality Degradation of Oil Palm Fresh Fruit Bunches (FFB)

    Science.gov (United States)

    Mat Sharif, Zainon Binti; Taib, Norhasnina Binti Mohd; Yusof, Mohd Sallehuddin Bin; Rahim, Mohammad Zulafif Bin; Tobi, Abdul Latif Bin Mohd; Othman, Mohd Syafiq Bin

    2017-05-01

    The main objective of this study is to determine the relationship between quality of oil palm fresh fruit bunches (FFB) and handling processes. The study employs exploratory and descriptive design, with quantitative approach and purposive sampling using self-administrated questionnaires, were obtained from 30 smallholder respondents from the Southern Region, Peninsular Malaysia. The study reveals that there was a convincing relationship between quality of oil palm fresh fruit bunches (FFB) and handling processes. The main handling process factors influencing quality of oil palm fresh fruit bunches (FFB) were harvesting activity and handling at the plantation area. As a result, it can be deduced that the handling process factors variable explains 82.80% of the variance that reflects the quality of oil palm fresh fruit bunches (FFB). The overall findings reveal that the handling process factors do play a significant role in the quality of oil palm fresh fruit bunches (FFB).

  17. Degradation of Antibiotics in Wastewater during Sonolysis, Ozonation, and Their Simultaneous Application: Operating Conditions Effects and Processes Evaluation

    Directory of Open Access Journals (Sweden)

    Vincenzo Naddeo

    2012-01-01

    Full Text Available Pharmaceutical drugs frequently found in treated effluents, lakes and rivers, can exhibit adverse effects on aquatic organisms. The present study focuses on the application of advanced oxidation processes as ozonation (O3, sonolysis (US, and their combined application (US+O3 for the degradation of diclofenac in wastewater. Under the applied conditions, all three systems proved to be able to induce diclofenac oxidation, leading to 22% of mineralization for O3 and 36% for US process after 40 min of treatment. The synergy observed in the combined schemes, mainly due to the effects of US in enhancing the O3 decomposition, led to a higher mineralization (about 40% for 40-minute treatment and to a significantly higher mineralization level for shorter treatment duration.

  18. Photosynthetic and Ultrastructure Parameters of Maize Plants are Affected During the Phyto-Rhizoremediation Process of Degraded Metal Working Fluids.

    Science.gov (United States)

    Grijalbo, Lucía; Gutierrez Mañero, Francisco Javier; Fernandez-Pascual, Mercedes; Lucas, Jose Antonio

    2015-01-01

    A phyto-rhizoremediation system using corn and esparto fiber as rooting support to remediate degraded metal working fluids (dMWFs) has been developed in the present study. In order to improve the process, plants were inoculated at the root level with bacteria either individually, and with a consortium of strains. All strains used were able to grow with MWFs. The results show that this system significantly lowers the Chemical Oxygen Demand below legal limits within 5 days. However, results were only improved with the bacterial consortium. Despite the effectiveness of the phyto-rhizoremediation process, plants are damaged at the photosynthetic level according to the photosynthetic parameters measured, as well as at the ultrastructure of the vascular cylinder and the Bundle Sheath Cells. Interestingly, the bacterial inoculation protects against this damage. Therefore, it seems that that the inoculation with bacteria can protect the plants against these harmful effects.

  19. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: Enhanced removal of aromatic amines

    International Nuclear Information System (INIS)

    Hosseini Koupaie, E.; Alavi Moghaddam, M.R.; Hashemi, S.H.

    2011-01-01

    Highlights: → Biofilm process was applied as post-treatment of anaerobically degraded an azo dye. → More than 65% of the dye total metabolites was completely mineralized. → Based on HPLC analysis, more than 80% of 1-naphthylamine-4-sulfonate was removed. → Inhibition of biofilm growth was increased with increasing the initial dye concentration. → Considerable porous morphology was observed in the SEM photographs of the biofilm. - Abstract: The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  20. Efficient peroxydisulfate activation process not relying on sulfate radical generation for water pollutant degradation

    KAUST Repository

    Zhang, Tao; Chen, Yin; Wang, Yuru; Le Roux, Julien; Yang, Yang; Croue, Jean-Philippe

    2014-01-01

    Peroxydisulfate (PDS) is an appealing oxidant for contaminated groundwater and toxic industrial wastewaters. Activation of PDS is necessary for application because of its low reactivity. Present activation processes always generate sulfate radicals

  1. The study analysis of degradation product of Tributyl Phosphate by Gamma radiation and influence in extraction process

    International Nuclear Information System (INIS)

    Damunir; Didiek Herhady, R; Busron-Masduki; Ashar-Waskito; Armanu

    1996-01-01

    The analysis study of degradation product of TBP by gamma radiation using Co-60 Irradiator Irvasena was done. The investigation stressed on analysis and the relation of degradation product of TBP and extraction process. TBP-dodecane 30 % irradiated by radiation doses 1.172x10 3 rad, 1.155x10 5 rad, 1.125x10 7 and 1.155x10 9 rad. The analysis of degradation product of TBP mainly of MBP and DBP were determined in the mixture media of 5 ml isopropyl alcohol, 5 ml ethylene glycol, 5 ml acetone and 15 ml alcohol with potentiometric titration using NaOH 0.1 N in the alcohol solution, at potential condition of 500 mV and potential derivative 500 mV. The experiment shows that the gamma radiation doses 1.125x10 7 rad result 0.125 ± 0.049 mg MBP/ml solvent and 1.556 ± 0.084 mg DBP/ml solvent and radiation doses 1.115x10 9 rad result 26.135 ± 0.114 mg MBP/ml solvent and 62.454 ± 1.107 mg DBP/ml solvent, MBP dan DBP un detectable for radiation doses 1.172x10 3 rad and 1.055x10 5 rad. The result of MBP and DBP analysis compare to Tachehiko Ishihara and Erich Zimmer, using potentiometric titration method for MBP and DBP analysis was reliable addition and none addition. The TBP-dodecane solvent was irradiation by radiation doses 10 7 rad or greater than, is suggested to treat the solvent by regeneration so that doesn't disturbance extraction

  2. Co-Occurring Disorders

    Science.gov (United States)

    ... the mental health field. Alcohol and Drug Abuse, Addiction and Co-occurring Disorders: Co-occurring Disorders and ... 500 Montgomery Street, Suite 820 Alexandria, VA 22314 Phone (703) 684.7722 Toll Free (800) 969.6642 ...

  3. Lipid oxidation and vitamin D3 degradation in simulated whole milk powder as influenced by processing and storage.

    Science.gov (United States)

    Mahmoodani, Fatemeh; Perera, Conrad O; Abernethy, Grant; Fedrizzi, Bruno; Chen, Hong

    2018-09-30

    Vitamin D3 levels are known to sometimes decline in fortified products, which could be due to its degradation, although the exact mechanism is unknown. In this study, the influence of processing and storage conditions on lipid oxidation and vitamin D3 degradation were studied. Simulated whole milk powders with and without heat treatment were stored for 12 months at two different storage temperatures (20 °C and 40 °C). Stored samples without heat treatment showed higher lipid oxidation products analyzed by PV and TBARS values compared to those with heat treatment. Higher storage temperature also resulted in higher levels of lipid oxidation products. The concentration of vitamin D3 was also analyzed using UHPLC-MS/MS after PTAD derivatization in stored samples. An inverse relationship was observed between lipid oxidation products and vitamin D3 content. Finally, previtamin D3 and vitamin D3 oxidation products were quantified in stored samples using MRM analysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Photochemical degradation of emerging contaminants by solar processes: analytical assessment; Degradacion fotoquimica de contaminantes emergentes mediante procesos solares. Evaluacion analitica

    Energy Technology Data Exchange (ETDEWEB)

    Perez Estrada, L. A.; Aguera Lopez, A.; Malato Rodriguez, S.

    2009-07-01

    In recent years, the presence of pharmaceuticals in the aquatic environment has reached a growing interest. These new contaminants are important because many of them are not degraded under the typical biological treatments applied in the wastewater treatment plants and represent a continuous input into the environment. Thus compounds such as diclofenac, dipyrone and malachite green are present in surface waters in all Europe and crucial need for more enhanced technologies that can reduce its presence in the environment has become evident. In this sense, solar advanced oxidation processes represent a good choice for the treatment of hazardous non-biodegradable pollutants. This work deals with the solar photodegradation of these contaminants in aqueous solutions by TiO{sub 2} photo catalysis and photo-Fenton reaction. A pilot-scale facility using a compound parabolic collector (CPC) reactor was used for this study. Results obtained show rapid and complete oxidation of parent compounds and partial mineralization of dissolved organic carbon. The two treatment are compared on the basis of their kinetics (parent compound and TOC), formation of degradation products (as determined by ionic chromatography, GC/MS and LC/TOF-MS), and toxicity (as evaluated by Vibrio fischeri bacteria). (Author)

  5. Degradation Dynamics and Dietary Risk Assessments of Two Neonicotinoid Insecticides during Lonicera japonica Planting, Drying, and Tea Brewing Processes.

    Science.gov (United States)

    Fang, Qingkui; Shi, Yanhong; Cao, Haiqun; Tong, Zhou; Xiao, Jinjing; Liao, Min; Wu, Xiangwei; Hua, Rimao

    2017-03-01

    The degradation dynamics and dietary risk assessments of thiamethoxam and thiacloprid during Lonicera japonica planting, drying, and tea brewing processes were systematically investigated using high-performance liquid chromatography. The half-lives of thiamethoxam and thiacloprid were 1.0-4.1 d in the honeysuckle flowers and leaves, with degradation rate constants k ranging from -0.169 to -0.696. The safety interval time was 7 d. The sun- and oven-drying (70 °C) percent digestions were 59.4-81.0% for the residues, which were higher than the shade- and oven-drying percentages at lower temperatures (30, 40, 50, and 60 °C, which ranged from 37.7% to 57.0%). The percent transfers of thiamethoxam and thiacloprid were 0-48.4% and 0-25.2%, respectively, for the different tea brewing conditions. On the basis of the results of this study, abiding by the safety interval time is important, and using reasonable drying methods and tea brewing conditions can reduce the transfer of thiamethoxam and thiacloprid to humans.

  6. Metagenomic Analysis of Subtidal Sediments from Polar and Subpolar Coastal Environments Highlights the Relevance of Anaerobic Hydrocarbon Degradation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Espinola, Fernando J.; Dionisi, Hebe M.; Borglin, Sharon; Brislawn, Colin J.; Jansson, Janet K.; Mac Cormack, Walter P.; Carroll, Jolynn; Sjoling, Sara; Lozada , Mariana

    2018-01-02

    In this work, we analyzed the community structure and metabolic potential of sediment microbial communities in high-latitude coastal environments subjected to low to moderate levels of chronic pollution. Subtidal sediments from four low-energy inlets located in polar and subpolar regions from both Hemispheres were analyzed using large-scale 16S rRNA gene and metagenomic sequencing. Communities showed high diversity (Shannon’s index 6.8 to 10.2), with distinct phylogenetic structures (<40% shared taxa at the Phylum level among regions) but similar metabolic potential in terms of sequences assigned to KOs. Environmental factors (mainly salinity, temperature, and in less extent organic pollution) were drivers of both phylogenetic and functional traits. Bacterial taxa correlating with hydrocarbon pollution included families of anaerobic or facultative anaerobic lifestyle, such as Desulfuromonadaceae, Geobacteraceae, and Rhodocyclaceae. In accordance, biomarker genes for anaerobic hydrocarbon degradation (bamA, ebdA, bcrA, and bssA) were prevalent, only outnumbered by alkB, and their sequences were taxonomically binned to the same bacterial groups. BssA-assigned metagenomic sequences showed an extremely wide diversity distributed all along the phylogeny known for this gene, including bssA sensu stricto, nmsA, assA, and other clusters from poorly or not yet described variants. This work increases our understanding of microbial community patterns in cold coastal sediments, and highlights the relevance of anaerobic hydrocarbon degradation processes in subtidal environments.

  7. Role of Nitrite in Processed Meat Products and its Degradation during their Storage

    OpenAIRE

    ILIRJANA BOCI; ELDA ZIU; GENTJANA BARDHI

    2014-01-01

    This paper represents the analytical data of nitrite level obtained from the experimental work done on meat processed samples taken from a meat processing plant in Tirana. There has been a long debate and health concern about the nitrite content in meat products. Nitrite is added to e.g. sausages, and hams and other meat products to preserve these products and keep them free from dangerous bacteria. Among the aims are preventing botulism, a dangerous food poison. But also it’s important to us...

  8. Application of noise analysis to investigate core degradation process during PHEBUS-FPT1 test

    International Nuclear Information System (INIS)

    Oguma, Ritsuo

    1997-01-01

    Noise analysis has been performed for measurement data obtained during PHEBUS-FPT1 test. The purpose of the study is to evaluate the applicability of the noise analysis to the following problems: To get more knowledge about the physical processes going on during severe core conditions; To better understand the core melting process; To establish appropriate on-line shut-down data. Results of the study indicate that the noise analysis is quite promising as a tool for investigating physical processes during the experiment. Compared with conventional approach of evaluating the signal's mean value behaviour, the noise analysis can provide additional, more detailed information: It was found that the neutron flux signal is subjected to additional reactivity perturbations in conjunction with fuel melting and relocation. This can easily be detected by applying noise analysis for the neutron flux signal. It has been demonstrated that the method developed in the present study can provide more accurate estimates of the onset of fuel relocation than using temperature signals from thermocouples in the thermal shroud. Moreover, the result suggests a potential of the present method for tracking the whole process of relocation. The result of the data analysis suggests a possibility of sensor diagnostics which may be important for confirming the quality and reliability of the recorded data. Based on the results achieved it is believed that the combined use of noise analysis and thermocouple signals will provide reliable shut-down criteria for the experiment. 8 refs

  9. Effects of hydrologic conditions on biogeochemical processes and organic pollutant degradation in salt marsh sediments

    Science.gov (United States)

    W. James Catallo

    2000-01-01

    This work addressed the influence of tidal vs. static hydrologic conditions on biogeochemical processes and the transformation of pollutant organic chemicals (eight representative N-, O-, and S-heterocycles (NOSHs) from coal chemicals, crude oils, and pyrogenic mixtures) in salt marsh sediments. The goals were to: (1) determine the effects of static (flooded, drained)...

  10. Pilot-scale UV/H2O2 advanced oxidation process for municipal reuse water: Assessing micropollutant degradation and estrogenic impacts on goldfish (Carassius auratus L.).

    Science.gov (United States)

    Shu, Zengquan; Singh, Arvinder; Klamerth, Nikolaus; McPhedran, Kerry; Bolton, James R; Belosevic, Miodrag; Gamal El-Din, Mohamed

    2016-09-15

    Low concentrations (ng/L-μg/L) of emerging micropollutant contaminants in municipal wastewater treatment plant effluents affect the possibility to reuse these waters. Many of those micropollutants elicit endocrine disrupting effects in aquatic organisms resulting in an alteration of the endocrine system. A potential candidate for tertiary municipal wastewater treatment of these micropollutants is ultraviolet (UV)/hydrogen peroxide (H2O2) as an advanced oxidation process (AOP) which was currently applied to treat the secondary effluent of the Gold Bar Wastewater Treatment Plant (GBWWTP) in Edmonton, AB, Canada. A new approach is presented to predict the fluence-based degradation rate constants (kf') of environmentally occurring micropollutants including carbamazepine [(0.87-1.39) × 10(-3) cm(2)/mJ] and 2,4-Dichlorophenoxyacetic acid (2,4-D) [(0.60-0.91) × 10(-3) cm(2)/mJ for 2,4-D] in a medium pressure (MP) UV/H2O2 system based on a previous bench-scale investigation. Rather than using removal rates, this approach can be used to estimate the performance of the MP UV/H2O2 process for degrading trace contaminants of concern found in municipal wastewater. In addition to the ability to track contaminant removal/degradation, evaluation of the MP UV/H2O2 process was also accomplished by identifying critical ecotoxicological endpoints (i.e., estrogenicity) of the treated wastewater. Using quantitative PCR, mRNA levels of estrogen-responsive (ER) genes ERα1, ERα2, ERβ1, ERβ2 and NPR as well as two aromatase encoding genes (CYP19a and CYP19b) in goldfish (Carassius auratus L.) were measured during exposure to the GBWWTP effluent before and after MP UV/H2O2 treatment (a fluence of 1000 mJ/cm(2) and 20 mg/L of H2O2) in spring, summer and fall. Elevated expression of estrogen-responsive genes in goldfish exposed to UV/H2O2 treated effluent (a 7-day exposure) suggested that the UV/H2O2 process may induce acute estrogenic disruption to goldfish principally because

  11. Role of activated carbon on micropollutans degradation by different radiation processes

    Directory of Open Access Journals (Sweden)

    Inmaculada Velo Gala

    2015-04-01

    Full Text Available The objective of this study was to analyse the influence of the presence of activated carbon on radiation processes. The triiodinated contrast medium diatrizoate was chosen as the contaminant model. We selected four commercial activated carbons and sixteen gamma radiation-modified carbons derived from these. The different advanced oxidation/reduction processes that have been studied were improved through the addition of activated carbon in the UV light and gamma radiating processes. In the UV/activated carbon process, the synergic activity of the activated carbon is enhanced in the samples with higher percentages of surface oxygen, ester/anhydride groups and carbon atoms with sp2 hybridization. Band gap determination of activated carbons revealed that they behave as semiconductor materials and, therefore, as photoactive materials in the presence of UV radiation, given that all band gap values are <4 eV. We also observed that the gamma radiation treatment reduces the band gap values of the activated carbons and that, in a single series of commercial carbons, lower band gap values correspond to higher contaminant removal rate values. We observed that the activity of the reutilized activated carbons is similar to that of the original carbons. Based on these results, we proposed that the activated carbon acts as a photocatalyst, promoting electrons of the valence band to the conduction band and increasing the generation of HO• radicals in the medium. Similarly, there was a synergic effect made by the presence of activated carbon in gamma radiation system, which favours pollutant removal. This synergic effect is independent of the textural but not the chemical characteristics of the activated carbon, observing a higher synergic activity for carbons with a higher surface content of oxygen, specifically quinone groups. We highlight that the synergic effect of the activated carbon requires adsorbent–adsorbate electrostatic interaction and is absent

  12. Humic Acid Degradation via Solar Photo-Fenton Process in Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Seyed Ali Sajjadi

    2015-08-01

    Full Text Available Control of mutagenic and carcinogenic disinfection by-products, particularly Trihalomethanes (THMs and Halo Acetic Acids (HAAs in water treatment process is critical, due to their adverse effects on human health. Generally, reducing the toxicity of these by-products hinges on prior removal of the precursor materials, such as Humic Acid (HA in drinking water. This study was conducted to investigate the role of some parameters that could affect the removal of HA, including HA (5 and 10 ppm and H2O2 (20, 40, 60, and 80 ppm initial concentrations, Iron (II, sulfate heptahydrate dosage (4, 8, 12, and 16 ppm, pH (2, 3, 4 and 5, Oxidation time (5, 10, 15 and 30 min, and Sunlight levels (322±13 kWm-2. To accelerate the process of HA removal, the Solar Photo-Fenton (SPF process was employed by direct irradiation of converged sunlight in a Parabolic Trough Collectors (PTC, with 3m2 effective area. HA levels were measured via quantifying Dissolved Organic Carbon (DOC concentrations by means of a TOC Analyzer method. The results showed that the SPF process is under control of the Fe & H2O2 ratio, the Fe2+ dosage and especially the pH quantity. In optimal condition, (pH: 4, oxidation time: 30min, initial HA levels: 50 ppm, H2O2 concentrations: 20 ppm Fe+2 levels: 4 ppm, the study found more than 98% DOC removal. In conclusion, the SPF, as an economically effective technique, could be applied for the removal of HA in aqueous environments.

  13. Pyrimethanil degradation by photo-Fenton process: Influence of iron and irradiance level on treatment cost.

    Science.gov (United States)

    Cabrera Reina, A; Miralles-Cuevas, S; Casas López, J L; Sánchez Pérez, J A

    2017-12-15

    This study evaluates the combined effect of photo-catalyst concentration and irradiance level on photo-Fenton efficiency when this treatment is applied to industrial wastewater decontamination. Three levels of irradiance (18, 32 and 46W/m 2 ) and three iron concentrations (8, 20 and 32mg/L) were selected and their influence over the process studied using a raceway pond reactor placed inside a solar box. For 8mg/L, it was found that there was a lack of catalyst to make use of all the available photons. For 20mg/L, the treatment always improved with irradiance indicating that the process was photo-limited. For 32mg/L, the excess of iron caused an excess of radicals production which proved to be counter-productive for the overall process efficiency. The economic assessment showed that acquisition and maintenance costs represent the lowest relative values. The highest cost was found to be the cost of the reagents consumed. Both sulfuric acid and sodium hydroxide are negligible in terms of costs. Iron cost percentages were also very low and never higher than 10.5% while the highest cost was always that of hydrogen peroxide, representing at least 85% of the reagent costs. Thus, the total costs were between 0.76 and 1.39€/m 3 . Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Damaging process of graphite - new model and its impact on degradation of materials performance

    International Nuclear Information System (INIS)

    Tanabe, T.; Muto, S.

    1999-01-01

    The most widely accepted model for development of defect structure in neutron irradiated graphite has been such that following the first production of a pair of an interstitial and vacancy, di-interstitials and vacancies are formed and their subsequent growth would result in the production of an interstitial plane or loop in-between the basal planes and vacancy clusters, respectively, which could cause the loss of thermal conductivity and dimensional change. Recently we have claimed that the formation of vacancy clusters and growth of the interstitial planes are not necessarily a unique interpretation of the damaging process. Instead, the damaging process is described by orientational disordering within the basal planes, i.e. fragmentation into small crystallites and rotation of their crystalline axes, change of stacking order and elongation of the interplanar spacing. The orientational disordering within the basal planes proceeds coordinately over a few layers with their layered correlation maintained. This process accompanies changes in bonding nature producing 5 member- and 7 member-atomic rings as appeared in fullerenes. This is so to speak ''self-restoring or reconstruction'' to maintain resonance bonds as strict as possible without the formation of dangling bonds. This paper reviews irradiation effects in graphite such as increase of hydrogen retention, loss of thermal conductivity and dimensional change on the bases of our new model, taking account of the changes of the bonding nature in irradiated graphite. (orig.)

  15. Oxidative degradation processes in synthetic and biological polymers as studied by pulse radiolysis experiments

    International Nuclear Information System (INIS)

    Schnabel, W.

    1986-01-01

    On the basis of pulse radiolysis experiments carried out with various polymers in dilute solution three modes of action of molecular oxygen, O 2 can be discriminated with respect to main-chain scission: (a) O 2 acts as a promoter, (b) O 2 acts as an inhibitor, and (c) O 2 acts as a fixing agent for main-chain breaks. The promoting mode of action (a) is due to the inhibition of simultaneously occurring intermolecular crosslinking and/or to the combination of peroxyl radicals with the subsequent formation of readily decomposing oxyl radicals. The inhibiting mode of action (b) pertains to the reaction of O 2 with macroradicals that otherwise undergo main-chain rupture. Fixing of main-chain ruptures (mode c) becomes important if macroradicals generated by a very fast rupture of bonds in the main chain are prone to recombine quickly. This mode of action was evidenced in the case of polybutenesulfone, where main-chain scission involves the extrusion of small segments of the chain. (author)

  16. Optimisation of decolourisation and degradation of Reactive Black 5 dye under electro-Fenton process using Fe alginate gel beads.

    Science.gov (United States)

    Iglesias, O; Fernández de Dios, M A; Rosales, E; Pazos, M; Sanromán, M A

    2013-04-01

    The aim of this work was to improve the ability of the electro-Fenton process using Fe alginate gel beads for the remediation of wastewater contaminated with synthetic dyes and using a model diazo dye such as Reactive Black 5 (RB5). Batch experiments were conducted to study the effects of main parameters, such as voltage, pH and iron concentration. Dye decolourisation, reduction of chemical oxygen demand (COD) and energy consumption were studied. Central composite face-centred experimental design matrix and response surface methodology were applied to design the experiments and to evaluate the interactive effects of the three studied parameters. A total of 20 experimental runs were set, and the kinetic data were analysed using first-order and second-order models. In all cases, the experimental data were fitted to the empirical second-order model with a suitable degree for the maximum decolourisation of RB5, COD reduction and energy consumption by electro-Fenton-Fe alginate gel beads treatment. Working with the obtained empirical model, the optimisation of the process was carried out. The second-order polynomial regression model suggests that the optimum conditions for attaining maximum decolourisation, COD reduction and energy consumption are voltage, 5.69 V; pH 2.24 and iron concentration, 2.68 mM. Moreover, the fixation of iron on alginate beads suggests that the degradation process can be developed under this electro-Fenton process in repeated batches and in a continuous mode.

  17. Effects of Planting and Processing Modes on the Degradation of Dithianon and Pyraclostrobin in Chinese Yam (Dioscorea spp.).

    Science.gov (United States)

    Shi, Kaiwei; Wu, Xujin; Ma, Jingwei; Zhang, Junfeng; Zhou, Ling; Wang, Hong; Li, Li

    2017-12-06

    The yam (Dioscorea spp.) is widely cultivated in China. The degradation of dithianon and pyraclostrobin in yams with different planting and processing treatments was investigated in this article. An analytical method for two pesticides in yam and yam plant was developed, and recoveries were between 77% and 93%, with relative standard deviations from 0.8% to 7.4%, respectively. On the basis of this method, half-lives for plants grown on stakes versus plants grown without stakes were compared. The results indicated that the half-life for pesticide residues for plants grown on stakes versus plants grown without stakes differed as 6.7 versus 3.1 days for dithianon and 5.4 versus 5.2 days for pyraclostrobin. Dithianon was significantly influenced by planting mode because of its low stability under sunlight. The processing factors of various processing treatments (hot air-drying, vacuum freeze-drying, microwave vacuum-drying, infrared-drying, steaming, and boiling) were all <1, indicating that those processes can reduce residues of two pesticides at different levels. Significant amounts of residues were removed during the boiling treatment, whereas the others showed less effect.

  18. Evaluation of the performance degradation at PAFC investigation of dealloying process of electrocatalysts with in-situ XRD

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Noriyuki; Uchida, Hiroyuki; Watanabe, Masahiro [Yamanashi Univ., Kofu (Japan)] [and others

    1996-12-31

    As a complementary research project to the demonstration project of 5MW and 1 MW PAFC plants, the mechanism and rate of deterioration of the cells and stacks have been studied from 1995 FY, with the objective of establishing an estimation method for the service life-time of the cell stacks. This work has been performed in the Basic Research Project, as part of that project on PAFC`s, selecting four subjects (Electrocatalysts degradation, Electrolyte fill-level, Cell material corrosion, Electrolyte loss) as the essential factors relating to the life-time. In this study, the effect of temperature and potential on the dealloying process of electrocatalysts was examined in H{sub 3}PO{sub 4} electrolyte with X-ray diffraction measurement.

  19. Simultaneous atrazine degradation and E. coli inactivation by simulated solar photo-Fenton-like process using persulfate.

    Science.gov (United States)

    Garkusheva, Natalya; Matafonova, Galina; Tsenter, Irina; Beck, Sara; Batoev, Valeriy; Linden, Karl

    2017-07-29

    This work evaluated the feasibility of a photo-Fenton-like process using persulfate (PS) and ferrous iron (Fe 2+ ) under simulated solar radiation for degrading the herbicide atrazine (ATZ, 6-Chloro-N-ethyl-N'-isopropyl-1,3,5-triazine-2,4-diamine) and inactivating E. coli. Milli Q water, lake water, and diluted wastewater effluents were spiked both simultaneously and separately with ATZ (4 mg/L) and E. coli (10 5 CFU/mL), and exposed to treatment. A method for determining the average irradiance throughout the water media in the UV(A+B) range of the Xe lamp emission was developed for bench-scale experiments. These values were used to calculate the UV(A+B) fluences and the solar UV(A+B) energy doses per unit of volume (Q UV(A+B) , kJ/L). The obtained kinetic data were presented versus energy dose. Treatment of lake water at near-neutral pH was ineffective via the photo-Fenton-like process, attaining only 20% ATZ removal and 1-log reduction of E. coli. In Milli Q water and wastewater, the complete degradation of ATZ in the absence of bacteria was observed at an average energy dose of 1.5 kJ/L (60 min), while in the presence of cells the degradation efficiency was ∼60%. When ATZ was present, E. coli inactivation was also affected in Milli Q water, with 1.4-log reduction (93%) at a dose of 1.6 kJ/L (60 min), whereas in wastewater complete inactivation was achieved at a lower dose of 1.3 kJ/L (45 min). The energy requirements on a Q UV(A+B) basis for simultaneous 90% ATZ removal and 99.99% E. coli inactivation in Milli Q water and wastewater were shown to be less than 10 kJ/L. This suggests the solar/PS/Fe 2+ system is promising for simultaneous treatment and disinfection of wastewater effluents.

  20. Comprehensive study of the influence of different environments on degradation processes in F8BT: Correlating optoelectronic properties with Raman measurements

    International Nuclear Information System (INIS)

    Linde, Sivan; Shikler, Rafi

    2013-01-01

    There is a growing interest in conjugated polymers from both industrial and academic points of views. The reasons are their tunable optoelectronic properties, ease of production, and excellent mechanical properties. However, the ease with which their optoelectronic properties are tunable make devices based on them prone to fast degradation and therefore, short life time. The issue of degradation of organic based optoelectronic devices is the topic of many ongoing researches. However, much less attention is given to degradation processes of the individual components of the devices and their dependence on the environmental conditions. In this work, we report on the degradation of a film of a polyfluorene block copolymer F8BT that is used in a variety of optoelectronic devices under different environments: Sun exposure, heating, and UV exposure in inert and ambient conditions. Degradation was observed in most of the optoelectronic properties of the film. Topographic measurements did not show observable changes of the film morphology following degradation. However, Raman spectroscopy measurements show changes that indicate degradation in one of the building blocks of the copolymer that is associated with electron's conduction. The absolute value of the correlation coefficient between the decrease in the Raman signal and the decrease in the optoelectronic properties is larger than 0.95 under sun exposure it is larger than 0.8 under all other ambient exposures and smaller than 0.65 under inert conditions. These results support the assumption that Oxygen, not necessarily through photo-oxidation, and also water play an important role in the degradation process and indicate the part of the polymer that is most susceptible to degradation

  1. Degradation of edible oil during food processing by ultrasound: electron paramagnetic resonance, physicochemical, and sensory appreciation.

    Science.gov (United States)

    Pingret, Daniella; Durand, Grégory; Fabiano-Tixier, Anne-Sylvie; Rockenbauer, Antal; Ginies, Christian; Chemat, Farid

    2012-08-08

    During ultrasound processing of lipid-containing food, some off-flavors can be detected, which can incite depreciation by consumers. The impacts of ultrasound treatment on sunflower oil using two different ultrasound horns (titanium and pyrex) were evaluated. An electron paramagnetic resonance study was performed to identify and quantify the formed radicals, along with the assessment of classical physicochemical parameters such as peroxide value, acid value, anisidine value, conjugated dienes, polar compounds, water content, polymer quantification, fatty acid composition, and volatiles profile. The study shows an increase of formed radicals in sonicated oils, as well as the modification of physicochemical parameters evidencing an oxidation of treated oils.

  2. Activated sludge treatment by electro-Fenton process: Parameter optimization and degradation mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Rahmani, Ali Reza; Azarian, Ghasem; Berizi, Zohreh [Hamadan University of Medical Sciences, Hamadan (Iran, Islamic Republic of); Nematollahi, Davood [Bu-Ali-Sina University, Hamadan (Iran, Islamic Republic of); Godini, Kazem [Ilam University of Medical Sciences, Ilam (Iran, Islamic Republic of)

    2015-08-15

    This study was conducted to evaluate the mineralization of activated sludge (MAS) by a facile and environmentally friendly electro-Fenton process (EFP). The effects of initial H{sub 2}O{sub 2} concentration, pH value, applied current density and operating time on MAS through determining the removal rate of chemical oxygen demand (COD) and total coliform (TC) were studied. 72% of COD was removed by indirect oxidation double-mediated based on the electro- generation of hydroxyl radical and active chlorine, under the following optimum conditions: 127mmol L{sup -}1 of hydrogen peroxide, pH=3.0, 10 mA cm{sup -}2 of DC current, 120min of operating time, and 0.22mol L{sup -}1 of NaCl as the supporting electrolyte. Only in 10 min and pH 3.0 approximately 100% of TC was removed. The findings indicated that EFP can be applied efficiently for MAS by selecting appropriate operating conditions. The bottom line is that the process is entirely effective owing to the application of green oxidants (hydroxyl radical and active chlorine) and lack of being influenced by environmental situations, which can be introduced as an alternative to current conventional methods.

  3. Activated sludge treatment by electro-Fenton process: Parameter optimization and degradation mechanism

    International Nuclear Information System (INIS)

    Rahmani, Ali Reza; Azarian, Ghasem; Berizi, Zohreh; Nematollahi, Davood; Godini, Kazem

    2015-01-01

    This study was conducted to evaluate the mineralization of activated sludge (MAS) by a facile and environmentally friendly electro-Fenton process (EFP). The effects of initial H 2 O 2 concentration, pH value, applied current density and operating time on MAS through determining the removal rate of chemical oxygen demand (COD) and total coliform (TC) were studied. 72% of COD was removed by indirect oxidation double-mediated based on the electro- generation of hydroxyl radical and active chlorine, under the following optimum conditions: 127mmol L - 1 of hydrogen peroxide, pH=3.0, 10 mA cm - 2 of DC current, 120min of operating time, and 0.22mol L - 1 of NaCl as the supporting electrolyte. Only in 10 min and pH 3.0 approximately 100% of TC was removed. The findings indicated that EFP can be applied efficiently for MAS by selecting appropriate operating conditions. The bottom line is that the process is entirely effective owing to the application of green oxidants (hydroxyl radical and active chlorine) and lack of being influenced by environmental situations, which can be introduced as an alternative to current conventional methods.

  4. Shutdown and degradation: Optimization of thermal cutting processes for the dismantling of nuclear facilities. Final report

    International Nuclear Information System (INIS)

    Schultz, H.; Hammer, G.; Hampe, A.; Homburg, A.

    1996-01-01

    Cutting processes are required for the dismantling of nuclear facilities which emit only a minimum of contaminated material in the form of shavings, sparks, dust, steam concentrate etc. and equipment which is easy to handle and can be remote controlled. A check of the usual mechanical, thermal and thermo-mechanical cutting procedures showed to what varying extent they are suitable for these tasks. Also the laser beam cutting was able to reduce the material discharge by optimal joints. For the investigation, the plasma cutting and the laser beam cutting were used with the aim of reducing considerably the material discharge by changing the adjust and device setting data for theses cases. The adapting of the speed and the amounts of gas turned out to be effective measures in reducing discharge. Adhesion of metal mass and slag in the joint edge could be achieved with aggressive bearth formation. The expectations made of the project could be fulfilled and process parameters for a pollutant optimised cutting determined. (orig.) [de

  5. Studying the degradation of polyhydroxybutyrate-co-valerate during processing with clay-based nanofillers

    DEFF Research Database (Denmark)

    Cabedo, Luis; Plackett, David; Gimenez, Enrique

    2009-01-01

    Polyhydroxybutyrate-co-valerate (PHBV) is attracting interest as a new material for packaging applications and nanoparticulate layered silicates are being increasingly explored as a way to improve PHBV film properties. In this context, it is essential to understand how different types of nanofill......Polyhydroxybutyrate-co-valerate (PHBV) is attracting interest as a new material for packaging applications and nanoparticulate layered silicates are being increasingly explored as a way to improve PHBV film properties. In this context, it is essential to understand how different types...... of nanofillers could influence polymer properties. PHBV was processed with three-layered clay types using different mixing methods, and we examined the effect of processing time, clay type, and clay content on polymer molecular weight and composite morphology. PHBV molecular weight (Mw) decreased by 38% after......-ray diffraction studies indicated an intercalated morphology in the presence of modified montmorillonite but good dispersion was also achieved when unmodified kaolinite was blended with PHBV. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009...

  6. Fate of naturally occurring Escherichia coli O157:H7 and other zoonotic pathogens during minimally managed bovine feedlot manure composting processes

    Science.gov (United States)

    Reducing Escherichia coli O157:H7 in livestock manures before application to cropland is critical for reducing the risk of foodborne illness associated with produce. Our objective was to determine the fate of naturally occurring E. coli O157:H7 and other pathogens during minimally managed on-farm bo...

  7. New concepts of microbial treatment processes for the nitrogen removal: effect of protein and amino acids degradation.

    Science.gov (United States)

    González-Martínez, Alejandro; Calderón, Kadiya; González-López, Jesús

    2016-05-01

    High concentrations of proteins and amino acids can be found in wastewater and wastewater stream produced in anaerobic digesters, having shown that amino acids could persist over different managements for nitrogen removal affecting the nitrogen removal processes. Nitrogen removal is completely necessary because of their implications and the significant adverse environmental impact of ammonium such as eutrophication and toxicity to aquatic life on the receiving bodies. In the last decade, the treatment of effluents with high ammonium concentration through anammox-based bioprocesses has been enhanced because these biotechnologies are cheaper and more environmentally friendly than conventional technologies. However, it has been shown that the presence of important amounts of proteins and amino acids in the effluents seriously affects the microbial autotrophic consortia leading to important losses in terms of ammonium oxidation efficiency. Particularly the presence of sulfur amino acids such as methionine and cysteine has been reported to drastically decrease the autotrophic denitrification processes as well as affect the microbial community structure promoting the decline of ammonium oxidizing bacteria in favor of other phylotypes. In this context we discuss that new biotechnological processes that improve the degradation of protein and amino acids must be considered as a priority to increase the performance of the autotrophic denitrification biotechnologies.

  8. [Decomposition of corpses--a microbial degradation process with special reference to mummification, formation of adipocere and incomplete putrified corpes].

    Science.gov (United States)

    Schoenen, Dirk

    2013-01-01

    Decomposition of the human body is a microbial process. It is influenced by the environmental situation and it depends to a high degree on the exchange of substances between the corpse and the environment. Mummification occurs at low humidity or frost. Adipocere arises from lack of oxygen, incomplete putrified corpses develop when there is no exchange of air or water between the corpse and the environment.

  9. Mechanism of azo dye degradation in Advanced Oxidation Processes: Degradation of Sulfanilic Acid Azochromotrop and its parent compounds in aqueous solution by ionizing radiation

    International Nuclear Information System (INIS)

    Palfi, Tamas; Wojnarovits, Laszlo; Takacs, Erzsebet

    2011-01-01

    Mechanistic studies were made on hydroxyl radical and hydrated electron reaction with Sulfanilic Acid Azochromotrop (SPADNS) as model azo dye in dilute aqueous solution. SPADNS contains 4,5-dihydroxynaphthalene-2,7-disulfonic acid part and 4-sulfophenylazo group. To establish the details of the reaction mechanism the reactions of two simpler molecules without 4-sulfophenylazo part were also studied: one of them contained one (in position 4, II), the other two (in positions 4 and 5, III) -OH groups. Hydroxyl radicals react with these molecules with radical addition to the naphthalene-2,7-disulfonic acid part. The adduct hydroxycyclohexadienyl type radical decays in radical-radical reactions, or undergoes a (pH dependent) water elimination to yield naphthoxy radical. The radical decay takes place on the ms timescale. Degradation efficiencies are 0.6-0.8. Hydrated electron in the case of the two simpler molecules reacts with the rings, while in the case of dye with the azo bond. Electron scavenging is followed by protonation, this reaction in the case of II and III yields cyclohexadienyl, while with the dye hydrazo radical. The efficiency of degradation with II and III is 0.2-0.6, while for SPADNS it is close to 1.

  10. TAILS N-Terminomics and Proteomics Show Protein Degradation Dominates over Proteolytic Processing by Cathepsins in Pancreatic Tumors

    Directory of Open Access Journals (Sweden)

    Anna Prudova

    2016-08-01

    Full Text Available Deregulated cathepsin proteolysis occurs across numerous cancers, but in vivo substrates mediating tumorigenesis remain ill-defined. Applying 8-plex iTRAQ terminal amine isotopic labeling of substrates (TAILS, a systems-level N-terminome degradomics approach, we identified cathepsin B, H, L, S, and Z in vivo substrates and cleavage sites with the use of six different cathepsin knockout genotypes in the Rip1-Tag2 mouse model of pancreatic neuroendocrine tumorigenesis. Among 1,935 proteins and 1,114 N termini identified by TAILS, stable proteolytic products were identified in wild-type tumors compared with one or more different cathepsin knockouts (17%–44% of 139 cleavages. This suggests a lack of compensation at the substrate level by other cathepsins. The majority of neo-N termini (56%–83% for all cathepsins was consistent with protein degradation. We validated substrates, including the glycolytic enzyme pyruvate kinase M2 associated with the Warburg effect, the ER chaperone GRP78, and the oncoprotein prothymosin-alpha. Thus, the identification of cathepsin substrates in tumorigenesis improves the understanding of cathepsin functions in normal physiology and cancer.

  11. Degradation of phenol with using of Fenton-like Processes from water

    Directory of Open Access Journals (Sweden)

    Ahmad Reza Yazdanbakhsh

    2015-08-01

    Full Text Available Phenol is one of the serious pollutants from the chemical and petrochemical industries. This pollutant due to its convoluted structure is resistant to biodegradation. One of the methods that are useful to remove this pollutant is advanced oxidation (AOP. A laboratory scale study was done on a synthetic wastewater containing phenol. All experiments were done in batch conditions and effect of variables pH, amount of hydrogen peroxide, iron dosage, contact time and an initial concentration on the phenol removal were tested. The remaining phenol concentration was evaluated using the DR-5000 device. In order to effect of these parameters, the experiment was performance at pH 2 to 6, 5 to 45 ml/ml of peroxide, and time of 5 to 60 minutes with 2 to 15 g/ml iron (Fe˚. The optimum pH, the ratio of hydrogen, Fe˚and time were 3, 15 ml, 8g and 5 minutes respectively. Chemical oxygen demand (COD index was chosen as the parameter for evaluation in this study. Result showed that mineralization of phenol was not complete. The COD removal efficiency was obtained 71%. According to the results of this study, Fenton-like process can be used for conversion organic resistant compounds to other compounds with lower toxicity.

  12. Effects of process variables on micromeritic properties and drug release of non-degradable microparticles

    Directory of Open Access Journals (Sweden)

    Mitra Jelvehgari

    2011-06-01

    Full Text Available Introduction: The purpose of this investigation was to evaluate microencapsulated controlled release preparation of theophylline using Eudragit RS 100 as the retardant material with high entrapment efficiency. Methods: Microspheres were prepared by the emulsion-solvent evaporation method. A mixed solvent system consisting of methanol and acetone and light liquid paraffin as oily phase were chosen. Sucrose stearate was used as the surfactant to stabilize the emulsification process. The prepared microspheres were characterized by drug loading, Fourier-transform infrared spectroscopy (FTIR, differential scanning colorimetry (DSC and scanning electron microscopy (SEM. The in vitro release studies were performed at pH 1.2 and 7.4 aqueous medium. Results: Increasing the concentration of emulsifier, sucrose fatty acid ester F-70, decreased the particle size which contributed to increased drug release rate. The drug loading microparticle Eudragit RS100 (1:6 showed 60-75% of entrapment and mean particle size 205.93-352.76 µm. The results showed that, an increase in the ratio of polymer: drug (F5, 6: 1 resulted in a reduction in the release rate of the drug which may be attributed to the hydrophobic nature of the polymer. Conclusion: The release of theophylline is influenced by the drug to polymer ratio and particle size. Drug release is controlled by diffusion and the best-fit release kinetic is Higuchi model.

  13. Effects of process variables on micromeritic properties and drug release of non-degradable microparticles.

    Science.gov (United States)

    Jelvehgari, Mitra; Barar, Jaleh; Nokhodchi, Ali; Shadrou, Sanam; Valizadeh, Hadi

    2011-01-01

    The purpose of this investigation was to evaluate microencapsulated controlled release preparation of theophylline using Eudragit RS 100 as the retardant material with high entrapment efficiency. Microspheres were prepared by the emulsion-solvent evaporation method. A mixed solvent system consisting of methanol and acetone and light liquid paraffin as oily phase were chosen. Sucrose stearate was used as the surfactant to stabilize the emulsification process. The prepared microspheres were characterized by drug loading, Fourier-transform infrared spectroscopy (FTIR), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The in vitro release studies were performed at pH 1.2 and 7.4 aqueous medium. Increasing the concentration of emulsifier, sucrose fatty acid ester F-70, decreased the particle size which contributed to increased drug release rate. The drug loading microparticle Eudragit RS100(1:6) showed 60-75% of entrapment and mean particle size 205.93-352.76 μm.The results showed that, an increase in the ratio of polymer: drug (F5, 6: 1) resulted in a reduction in the release rate of the drug which may be attributed to the hydrophobic nature of the polymer. The release of theophylline is influenced by the drug to polymer ratio and particle size. Drug release is controlled by diffusion and the best-fit release kinetic is Higuchi model.

  14. Effect of Alumina Addition to Zirconia Nano-composite on Low Temperature Degradation Process and Biaxial Strength

    Directory of Open Access Journals (Sweden)

    Moluk Aivazi

    2016-12-01

    Full Text Available Ceramic dental materials have been considered as alternatives to metals for dental implants application. In this respect, zirconia tetragonal stabilized with %3 yttrium, is of great importance among the ceramic materials for endosseous dental implant application. Because of its good mechanical properties and color similar to tooth. The aim and novelty of this study was to design and prepare Y-TZP nano-composite to reduce the degradation process at low temperature by alumina addition and maintaining submicron grain sized. Also, flexural strength of nano-composite samples was evaluated. Toward this purpose, alumina-Y-TZP nano-composites containing 0–30 vol% alumina (denoted as A-Y-TZP 0-30 were fabricated using α-alumina and Y-TZP nano-sized by sintering pressure less method. The synthesized samples were characterized using x-ray diffraction, field emission scanning electron microscopy equipped with energy dispersive x-ray spectroscopy techniques. Nano-composite samples with high density (≥96% and grain sized of ≤ 400 nm was obtained by sintering at 1270 °C for 170 min. After low temperature degradation test (LTD, A-Y-TZP20 and A-Y-TZP30 not showed monoclinic phase and the flexural strength in all of samples were higher than A-Y-TZP0. It was concluded that the grains were remained in submicron sized and A-Y-TZP20 and A-Y-TZP30 did not present biaxial strength reduction after LTD test.

  15. Reactive transport modeling of chemical and isotope data to identify degradation processes of chlorinated ethenes in a diffusion-dominated media

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Damgaard, Ida; Jeannottat, Simon

    . Degradation and transport processes of chlorinated ethenes are not well understood in such geological settings, therefore risk assessment and remediation at these sites are particularly challenging. In this work, a combined approach of chemical and isotope analysis on core samples, and reactive transport...... the source zone (between 6 and 12 mbs). Concentrations and stable isotope ratios of the mother compounds and their daughter products, as well as redox parameters, fatty acids and microbial data, were analyzed with discrete sub-sampling along the cores. More samples (each 5 mm) were collected around...... of dechlorination and degradation pathways (biotic reductive dechlorination or abiotic β-elimination with iron minerals) in three core profiles. The model includes diffusion in the matrix, sequential reductive dechlorination, abiotic degradation, isotope fractionation due to degradation and due to diffusion...

  16. Natural Hematite and Siderite as Heterogeneous Catalysts for an Effective Degradation of 4-Chlorophenol via Photo-Fenton Process

    Directory of Open Access Journals (Sweden)

    Haithem Bel Hadjltaief

    2018-06-01

    Full Text Available This paper describes a simple and low-cost process for the degradation of 4-Chlorophenol (4-CP from aqueous solution, using natural Tunisian Hematite (M1 and Siderite (M2. Two natural samples were collected in the outcroppings of the Djerissa mining site (Kef district, northwestern Tunisia. Both Hematite and Siderite ferrous samples were characterized using several techniques, including X-Ray Diffraction (XRD, Nitrogen Physisorption (BET, Infrared Spectroscopy (FTIR, H2-Temperature Programmed Reduction (H2-TPR, Scanning Electronic Microscopy (SEM linked with Energy Dispersive X-ray (EDS and High-Resolution Transmission Electron Microscopy (HRTEM. Textural, structural and chemical characterization confirmed the presence of Hematite and Siderite phases with a high amount of iron on the both surface materials. Their activity was evaluated in the oxidation of 4-CP in aqueous medium under heterogeneous photo-Fenton process. Siderite exhibited higher photocatalytic oxidation activity than Hematite at pH 3. The experimental results also showed that 100% conversion of 4-CP and 54% TOC removal can be achieved using Siderite as catalyst. Negligible metal leaching and catalyst reutilization without any loss of activity point towards an excellent catalytic stability for both natural catalysts.

  17. Evidence for photolytic and microbial degradation processes in the dissipation of leptospermone, a natural β-triketone herbicide.

    Science.gov (United States)

    Romdhane, Sana; Devers-Lamrani, Marion; Martin-Laurent, Fabrice; Jrad, Amani Ben; Raviglione, Delphine; Salvia, Marie-Virginie; Besse-Hoggan, Pascale; Dayan, Franck E; Bertrand, Cédric; Barthelmebs, Lise

    2017-07-17

    Bioherbicides appear as an ecofriendly alternative to synthetic herbicides, generally used for weed management, because they are supposed to have low side on human health and ecosystems. In this context, our work aims to study abiotic (i.e., photolysis) and biotic (i.e,. biodegradation) processes involved in the fate of leptospermone, a natural β-triketone herbicide, by combining chemical and microbiological approaches. Under controlled conditions, the photolysis of leptospermone was sensitive to pH. Leptospermone has a half-life of 72 h under simulated solar light irradiations. Several transformation products, including hydroxy-leptospermone, were identified. For the first time, a bacterial strain able to degrade leptospermone was isolated from an arable soil. Based on its 16S ribosomal RNA (rRNA) gene sequence, it was affiliated to the Methylophilus group and was accordingly named as Methylophilus sp. LS1. Interestingly, we report that the abundance of OTUs, similar to the 16S rRNA gene sequence of Methylophilus sp. LS1, was strongly increased in soil treated with leptospermone. The leptospermone was completely dissipated by this bacteria, with a half-life time of 6 days, allowing concomitantly its growth. Hydroxy-leptospermone was identified in the bacterial culture as a major transformation product, allowing us to propose a pathway of transformation of leptospermone including both abiotic and biotic processes.

  18. Thermal stress during RTP processes and its possible effect on the light induced degradation in Cz-Si wafers

    Science.gov (United States)

    Kouhlane, Yacine; Bouhafs, Djoudi; Khelifati, Nabil; Guenda, Abdelkader; Demagh, Nacer-Eddine; Demagh, Assia; Pfeiffer, Pierre; Mezghiche, Salah; Hetatache, Warda; Derkaoui, Fahima; Nasraoui, Chahinez; Nwadiaru, Ogechi Vivian

    2018-04-01

    In this study, the carrier lifetime variation of p-type boron-doped Czochralski silicon (Cz-Si) wafers was investigated after a direct rapid thermal processing (RTP). Two wafers were passivated by silicon nitride (SiNx:H) layers, deposited by a PECVD system on both surfaces. Then the wafers were subjected to an RTP cycle at a peak temperature of 620 °C. The first wafer was protected (PW) from the direct radiative heating of the RTP furnace by placing the wafer between two as-cut Cz-Si shield wafers during the heat processing. The second wafer was not protected (NPW) and followed the same RTP cycle procedure. The carrier lifetime τ eff was measured using the QSSPC technique before and after illumination for 5 h duration at 0.5 suns. The immediate results of the measured lifetime (τ RTP ) after the RTP process have shown a regeneration in the lifetime of the two wafers with the PW wafer exhibiting an important enhancement in τ RTP as compared to the NPW wafer. The QSSPC measurements have indicated a good stable lifetime (τ d ) and a weak degradation effect was observed in the case of the PW wafer as compared to their initial lifetime value. Interferometry technique analyses have shown an enhancement in the surface roughness for the NPW wafer as compared to the protected one. Additionally, to improve the correlation between the RTP heat radiation stress and the carrier lifetime behavior, a simulation of the thermal stress and temperature profile using the finite element method on the wafers surface at RTP peak temperature of 620 °C was performed. The results confirm the reduction of the thermal stress with less heat losses for the PW wafer. Finally, the proposed method can lead to improving the lifetime of wafers by an RTP process at minimum energy costs.

  19. The structures of bacteriophages K1E and K1-5 explain processive degradation of polysaccharide capsules and evolution of new host specificities.

    Science.gov (United States)

    Leiman, Petr G; Battisti, Anthony J; Bowman, Valorie D; Stummeyer, Katharina; Mühlenhoff, Martina; Gerardy-Schahn, Rita; Scholl, Dean; Molineux, Ian J

    2007-08-17

    External polysaccharides of many pathogenic bacteria form capsules protecting the bacteria from the animal immune system and phage infection. However, some bacteriophages can digest these capsules using glycosidases displayed on the phage particle. We have utilized cryo-electron microscopy to determine the structures of phages K1E and K1-5 and thereby establish the mechanism by which these phages attain and switch their host specificity. Using a specific glycosidase, both phages penetrate the capsule and infect the neuroinvasive human pathogen Escherichia coli K1. In addition to the K1-specific glycosidase, each K1-5 particle carries a second enzyme that allows it to infect E. coli K5, whose capsule is chemically different from that of K1. The enzymes are organized into a multiprotein complex attached via an adapter protein to the virus portal vertex, through which the DNA is ejected during infection. The structure of the complex suggests a mechanism for the apparent processivity of degradation that occurs as the phage drills through the polysaccharide capsule. The enzymes recognize the adapter protein by a conserved N-terminal sequence, providing a mechanism for phages to acquire different enzymes and thus to evolve new host specificities.

  20. The influence of grazing intensity on soil properties and degradation processes in Mediterranean rangelands (Extremadura, SW Spain)

    Science.gov (United States)

    Pulido-Fernández, Manuel; Schnabel, Susanne; Francisco Lavado-Contador, Joaquín

    2014-05-01

    Rangelands cover vast extensions of land in Spain (>90,000 km2), where a total amount of 13 millions of domestic animals graze extensively their pastures. By clear-cutting shrubs, removing selected trees and by cultivation, these rangelands were created from former Mediterranean oak forests, mainly composed by holm oak and cork oak (Quercus ilex rotundifolia and Q. suber) as tree species, Nowadays this land system is exploited economically in large farms (>100 ha), most of them held on private ownership (80% of total) and dedicated to extensive ranching. Overgrazing is common and the excessive stocking rates may deteriorate soil quality, causing economic losses and environmental damage. Many studies have been developed on the effects of livestock grazing over soil properties and degradation processes, most of them by only comparing extreme cases (e.g. ungrazed vs. grazed or overgrazed areas). The main goal of this study is to contribute to the understanding on how animal grazing affects soil properties and degradation processes. The study is particularly focused on soil compaction and sheet erosion as related to the reduction of vegetation cover by defoliation. Soil properties were analysed from 119 environmental units selected from 56 farms distributed throughout the region of Extremadura (SW Spain). The units are representative of different rangeland types, i.e. scrublands of Retama sphaerocarpa, dehesas (wooded rangelands) and treeless grasslands. Soil surface cover was determined along transects in September 2010 (antecedent rainfall: 413-923 mm) considering the following classes: bare ground, grasses, mosses, litter, stones (<2 mm) and rock outcrops. Farmer interviews were also conducted in order to quantify stocking rates and to assess land management in 12 out of 56 farms. In the farms where transects and farmer interviews could not be carried out, bare soil surface and livestock densities were estimated. Bare soil surface was determined by classifying

  1. Degradation of the fungicide carbendazim in aqueous solutions with UV/TiO{sub 2} process: Optimization, kinetics and toxicity studies

    Energy Technology Data Exchange (ETDEWEB)

    Saien, J. [Department of Applied Chemistry, Bu-Ali Sina University, Hamedan 65174 (Iran, Islamic Republic of)], E-mail: saien@basu.ac.ir; Khezrianjoo, S. [Department of Applied Chemistry, Bu-Ali Sina University, Hamedan 65174 (Iran, Islamic Republic of)

    2008-09-15

    An attempt was made to investigate the potential of UV-photocatalytic process in the presence of TiO{sub 2} particles for the degradation of carbendazim (C{sub 9}H{sub 9}N{sub 3}O{sub 2}), a fungicide with a high worldwide consumption but considered as a 'priority hazard substance' by the Water Framework Directive of the European Commission (WFDEC). A circulating upflow photo-reactor was employed and the influence of catalyst concentration, pH and temperature were investigated. The results showed that degradation of this fungicide can be conducted in the both processes of only UV-irradiation and UV/TiO{sub 2}; however, the later provides much better results. Accordingly, a degradation of more than 90% of fungicide was achieved by applying the optimal operational conditions of 70 mg L{sup -1} of catalyst, natural pH of 6.73 and ambient temperature of 25 deg. C after 75 min irradiation. Under these mild conditions, the initial rate of degradation can be described well by the Langmuir-Hinshelwood kinetic model. Toxicological assessments on the obtained samples were also performed by measurement of the mycelium growth inhibition of Fusarium oxysporum fungus on PDA medium. The results indicate that the kinetics of degradation and toxicity are in reasonably good agreement mainly after 45 min of irradiation; confirming the effectiveness of photocatalytic process.

  2. A Time-Variant Reliability Model for Copper Bending Pipe under Seawater-Active Corrosion Based on the Stochastic Degradation Process

    Directory of Open Access Journals (Sweden)

    Bo Sun

    2018-03-01

    Full Text Available In the degradation process, the randomness and multiplicity of variables are difficult to describe by mathematical models. However, they are common in engineering and cannot be neglected, so it is necessary to study this issue in depth. In this paper, the copper bending pipe in seawater piping systems is taken as the analysis object, and the time-variant reliability is calculated by solving the interference of limit strength and maximum stress. We did degradation experiments and tensile experiments on copper material, and obtained the limit strength at each time. In addition, degradation experiments on copper bending pipe were done and the thickness at each time has been obtained, then the response of maximum stress was calculated by simulation. Further, with the help of one kind of Monte Carlo method we propose, the time-variant reliability of copper bending pipe was calculated based on the stochastic degradation process and interference theory. Compared with traditional methods and verified by maintenance records, the results show that the time-variant reliability model based on the stochastic degradation process proposed in this paper has better applicability in the reliability analysis, and it can be more convenient and accurate to predict the replacement cycle of copper bending pipe under seawater-active corrosion.

  3. Intrinsic immunogenicity of rapidly-degradable polymers evolves during degradation.

    Science.gov (United States)

    Andorko, James I; Hess, Krystina L; Pineault, Kevin G; Jewell, Christopher M

    2016-03-01

    Recent studies reveal many biomaterial vaccine carriers are able to activate immunostimulatory pathways, even in the absence of other immune signals. How the changing properties of polymers during biodegradation impact this intrinsic immunogenicity is not well studied, yet this information could contribute to rational design of degradable vaccine carriers that help direct immune response. We use degradable poly(beta-amino esters) (PBAEs) to explore intrinsic immunogenicity as a function of the degree of polymer degradation and polymer form (e.g., soluble, particles). PBAE particles condensed by electrostatic interaction to mimic a common vaccine approach strongly activate dendritic cells, drive antigen presentation, and enhance T cell proliferation in the presence of antigen. Polymer molecular weight strongly influences these effects, with maximum stimulation at short degradation times--corresponding to high molecular weight--and waning levels as degradation continues. In contrast, free polymer is immunologically inert. In mice, PBAE particles increase the numbers and activation state of cells in lymph nodes. Mechanistic studies reveal that this evolving immunogenicity occurs as the physicochemical properties and concentration of particles change during polymer degradation. This work confirms the immunological profile of degradable, synthetic polymers can evolve over time and creates an opportunity to leverage this feature in new vaccines. Degradable polymers are increasingly important in vaccination, but how the inherent immunogenicity of polymers changes during degradation is poorly understood. Using common rapidly-degradable vaccine carriers, we show that the activation of immune cells--even in the absence of other adjuvants--depends on polymer form (e.g., free, particulate) and the extent of degradation. These changing characteristics alter the physicochemical properties (e.g., charge, size, molecular weight) of polymer particles, driving changes in

  4. Lactose contaminant as steroid degradation enhancer

    NARCIS (Netherlands)

    Nieuwmeyer, Florentine; Maarschalk, Kees van der Voort; Vromans, Herman

    2008-01-01

    Purpose. By pharmaceutical processes and in the presence of solid excipients physical-chemical changes are known to occur, leading to increased rate of chemical degradation. The purpose of this work was to determine the critical aspects in the stability of a steroid in the presence of a commonly

  5. Lactose contaminant as steroid degradation enhancer

    NARCIS (Netherlands)

    Nieuwmeyer, Florentine; Maarschalk, Kees van der Voort; Vromans, Herman

    Purpose. By pharmaceutical processes and in the presence of solid excipients physical-chemical changes are known to occur, leading to increased rate of chemical degradation. The purpose of this work was to determine the critical aspects in the stability of a steroid in the presence of a commonly

  6. Degradation and detection of transgenic Bacillus thuringiensis DNA and proteins in flour of three genetically modified rice events submitted to a set of thermal processes.

    Science.gov (United States)

    Wang, Xiaofu; Chen, Xiaoyun; Xu, Junfeng; Dai, Chen; Shen, Wenbiao

    2015-10-01

    This study aimed to investigate the degradation of three transgenic Bacillus thuringiensis (Bt) genes (Cry1Ab, Cry1Ac, and Cry1Ab/Ac) and the corresponding encoded Bt proteins in KMD1, KF6, and TT51-1 rice powder, respectively, following autoclaving, cooking, baking, or microwaving. Exogenous Bt genes were more stable than the endogenous sucrose phosphate synthase (SPS) gene, and short DNA fragments were detected more frequently than long DNA fragments in both the Bt and SPS genes. Autoclaving, cooking (boiling in water, 30 min), and baking (200 °C, 30 min) induced the most severe Bt protein degradation effects, and Cry1Ab protein was more stable than Cry1Ac and Cry1Ab/Ac protein, which was further confirmed by baking samples at 180 °C for different periods of time. Microwaving induced mild degradation of the Bt and SPS genes, and Bt proteins, whereas baking (180 °C, 15 min), cooking and autoclaving led to further degradation, and baking (200 °C, 30 min) induced the most severe degradation. The findings of the study indicated that degradation of the Bt genes and proteins somewhat correlated with the treatment intensity. Polymerase chain reaction, enzyme-linked immunosorbent assay, and lateral flow tests were used to detect the corresponding transgenic components. Strategies for detecting transgenic ingredients in highly processed foods are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. An insight into the adsorption and electrochemical processes occurring during the analysis of copper and lead in wines, using an electrochemical quartz crystal nanobalance.

    Science.gov (United States)

    Yamasaki, Alzira; Oliveira, João A B P; Duarte, Armando C; Gomes, M Teresa S R

    2012-08-30

    Copper and lead in wine were quantified by anodic stripping voltammetry (ASV), performed onto the gold electrode of a piezoelectric quartz crystal. Both current or mass changes could be used as analytical signals, without a statistical difference in the results (α=0.05). However, the plot of mass vs. potential provided an in depth understanding of the electrochemical processes and allowed studying adsorption phenomena. Copper interaction with fructose is an example of a process which was not possible to ignore by observing the mass change on the gold electrode of the piezoelectric quartz crystal. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Degradability of dry matter and crude protein of dry grains and wet grain silages from different processing corn hybrids (Zea mays)

    OpenAIRE

    Wagner dos Reis; Ciniro Costa; Paulo Roberto de Lima Meirelles; Marina Gabriela Berchiol da Silva; Marco Aurélio Factori; Janaína Conte Hadlich; Kátia de Oliveira; Erikelly Aline Ribeiro de Santana; Cristiano Magalhães Pariz; Josineudson Augusto II de Vasconcelos Silva

    2013-01-01

    The objective of this work was to evaluate the effect of processing two corn hybrids conserved, dry and humid grains, the dry matter (DM) and crude protein (CP) degradability in situ. The particle size was determined and difference was verified in MGD (Medium Geometric Diameter) of processed ingredients. Three sheep were used with rumen canulated, in a completely randomized design, using a factorial outline 2 x 2 x 3, being two corn hybrid, two conservation methods and three processing forms ...

  9. Evaluations of the technical changes and social interactions that occurred during the participatory process, and summarizing on improved scientific skills. Jakfish Deliverable 6.1

    DEFF Research Database (Denmark)

    Röckmann, Christine; Ulrich, Clara; Dreyer, Marion

    Holders) invited fisheries stakeholders to participate in the process of framing the management problem, and to give input and evaluate the scientific models that are used to provide fisheries management advice. JAKFISH investigated various tools to assess and communicate uncertainty around fish stock assessments...

  10. Elimination of pyraclostrobin by simultaneous microbial degradation coupled with the Fenton process in microbial fuel cells and the microbial community.

    Science.gov (United States)

    Zhao, Huanhuan; Kong, Chui-Hua

    2018-06-01

    The elimination of pyraclostrobin by simultaneous microbial degradation and Fenton oxidation was achieved in a microbial fuel cell (MFC) system. After 12 h of incubation, the removal rate of pyraclostrobin was 1.4 mg/L/h at the anode and 1.7 mg/L/h at the cathode. The pyraclostrobin concentration was less than the detection limit (0.1 mg/L) after 72 h at the anode and 24 h at the cathode. The air flow rate, temperature, and pH of the catholyte had significant effects on the generation of H 2 O 2 . The maximum production of H 2 O 2 was 1.2 mg/L after reaction for 20 h during the Fenton process. Microbial community analysis indicated that functional bacteria in the genera Chryseobacterium, Stenotrophomonas, Arcobacter, and Comamonas were predominant in the anodic biofilm. In conclusion, the MFC-Fenton system provides an effective approach for treating environmental contaminants. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Influence of strain hardening and thickness changes occurring in press forming process; Seikeiji no kako koka/itaatsu henka no buzai akkai tokusei ni oyobosu eikyo bunseki

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, M; Hirota, K [Mazda Motor Corp., Hiroshima (Japan); Nakazawa, Y [Sumitomo Metal Industries Ltd., Osaka (Japan)

    1997-10-01

    Most components of the body structure are produced by press forming. This process make a uniform metal sheet into a component that have various material characteristics and thickness. This paper describes the estimation method of material characteristics and thickness changes based on the measured Vickers hardness, and the influence of these changes on the crush performance by using FE analysis. 4 refs., 12 figs., 2 tabs.

  12. The kinetics of sterane biological marker release and degradation processes during the hydrous pyrolysis of vitrinite kerogen

    Science.gov (United States)

    Abbott, G. D.; Wang, G. Y.; Eglinton, T. I.; Home, A. K.; Petch, G. S.

    1990-09-01

    The hydrous pyrolysis of a mineral-free vitrinite kerogen (Dinantian coal Lower Carboniferous, North East England) has been carried out at four temperatures (270, 300, 330, and 350°C) for heating times ranging from 2 to 648 h. No significant differences in the epimer-based maturation parameters 20S/(20S + 20R)-5α(H),14α(H),17α(H) C 29 non-rearranged steranes and 22S/(22S+22R)-17α(H), 21β(H) homohopanes were found for a comparison between "expelled oil" and "bitumen" fractions in the resulting pyrolysates. A deuterated model compound ((20R)-5α(H),14α(H),17α(H)-[2,2,4,4-d 4] cholestane) was added to a number of preextracted kerogens (vitrinite, Kimmeridge, Messel and Monterey) and the mixtures were heated under typical hydrous pyrolysis conditions. These experiments showed that direct chiral isomerisation at C-20 in the non-rearranged steranes appears to be relatively unimportant during hydrous pyrolysis which has also been suggested by other recent studies on geological samples.A kinetic model comprising consecutive release and degradation processes was derived to measure first-order rate coefficients from the bi-exponential concentration-time functions of both the (20R)-and (20S)-5α(H),14α(H),17α(H) C 29 "free" steranes in the vitrinite kerogen pyrolysates. This data was then used to calculate preliminary Arrhenius parameters for release ((20S): ΔEa = 125 ± 30 kJ mol -1, A ≈ 4.7 × 10 5 s -1;(20R): ΔEa = 151 ± 39 kJ mol -1, A ≈ 2.7 × 10 9 s -1) and degradation ((20S): ΔEa = 104 ± 22 kJ mol -1, A ≈ 5.8 × 10 3 s -1; (20R): Δa = 87 ± 6 kJ mol -1, A ≈ 2.2 × 10 2 s -1) of the above individual isomers and the values were found to be consistent with a free-radical chain mechanism. This work helps in the greater understanding of the important biomarker reactions that prevail in hydrous pyrolysis experiments.

  13. A Fe(II)/citrate/UV/PMS process for carbamazepine degradation at a very low Fe(II)/PMS ratio and neutral pH: The mechanisms.

    Science.gov (United States)

    Ling, Li; Zhang, Dapeng; Fan, Chihhao; Shang, Chii

    2017-11-01

    A novel Fe(II)/citrate/UV/PMS process for degrading a model micropollutant, carbamazepine (CBZ), at a low Fe(II)/PMS ratio and neutral pH has been proposed in this study, and the mechanisms of radical generation in the system was explored. With a UV dose of 302.4 mJ/cm 2 , an initial pH of 7, and CBZ, PMS, Fe(II) and citrate at initial concentrations of 10, 100, 12 and 26 μM, respectively, the CBZ degradation efficiency reached 71% in 20 min in the Fe(II)/citrate/UV/PMS process, which was 4.7 times higher than that in either the citrate/UV/PMS or Fe(II)/citrate/PMS process. The enhanced CBZ degradation in the Fe(II)/citrate/UV/PMS process was mainly attributed to the continuous activation of PMS by the UV-catalyzed regenerated Fe(II) from a Fe(III)-citrate complex, [Fe 3 O(cit) 3 H 3 ] 2- , which not only maintained Fe(III) soluble at neutral pH, but also increased 6.6 and 2.6 times of its molar absorbance and quantum yield as compared to those of ionic Fe(III), respectively. In the Fe(II)/citrate/UV/PMS process, the SO 4 •- produced from the fast reaction between PMS and the initially-added Fe(II) contributed 11% of CBZ degradation. The PMS activation by the UV radiation and regenerated Fe(II) contributed additional 14% and 46% of CBZ removal, respectively. The low iron and citrate doses and the fast radical generation at neutral pH make the Fe(II)/citrate/UV/PMS process suitable for degrading recalcitrant organic compounds in potable water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Developments in polymer degradation - 7

    International Nuclear Information System (INIS)

    Grassie, N.

    1987-01-01

    A selection of topics which are representative of the continually expanding area of polymer degradation is presented. The aspects emphasised include the products of degradation of specific polymers, degradation by high energy radiation and mechanical forces, fire retardant studies and the special role of small radicals in degradation processes. (author)

  15. Redox markers for drought-induced nodule senescence, a process occurring after drought-induced senescence of the lowest leaves in soybean (Glycine max).

    Science.gov (United States)

    Marquez-Garcia, Belén; Shaw, Daniel; Cooper, James William; Karpinska, Barbara; Quain, Marian Dorcas; Makgopa, Eugene Matome; Kunert, Karl; Foyer, Christine Helen

    2015-09-01

    Water is an increasingly scarce resource that limits crop productivity in many parts of the world, and the frequency and severity of drought are predicted to increase as a result of climate change. Improving tolerance to drought stress is therefore important for maximizing future crop yields. The aim of this study was to compare the effects of drought on soybean (Glycine max) leaves and nodules in order to define phenotypic markers and changes in cellular redox state that characterize the stress response in different organs, and to characterize the relationships between leaf and nodule senescence during drought. Leaf and crown nodule metabolite pools were measured together with leaf and soil water contents, and leaf chlorophyll, total protein contents and chlorophyll a fluorescence quenching parameters in nodulated soybeans that were grown under either well-watered conditions or deprived of water for up to 21 d. Ureides, ascorbate, protein, chlorophyll and the ratios of variable chlorophyll a fluorescence (Fv') to maximal chlorophyll a fluorescence (Fm') fell to levels below detection in the oldest leaves after 21 d of drought. While these drought-induced responses were not observed in the youngest leaf ranks, the Fv'/Fm' ratios, pyridine nucleotide levels and the reduction state of the ascorbate pool were lower in all leaf ranks after 21 d of drought. In contrast to leaves, total nodule protein, pyridine nucleotides, ureides, ascorbate and glutathione contents increased as a result of the drought treatment. However, the nodule ascorbate pool was significantly less reduced as a result of drought. Higher levels of transcripts encoding two peroxiredoxins were detected in nodules exposed to drought stress but senescence-associated transcripts and other mRNAs encoding redox-related proteins were similar under both conditions. While the physiological impact of the drought was perceived throughout the shoot, stress-induced senescence occurred only in the oldest

  16. Study by 31P NMR spectroscopy of the triacylglycerol degradation processes in olive oil with different heat-transfer mechanisms.

    OpenAIRE

    Lucas Torres, Covadonga; Pérez Martínez, Angel; Cabañas Galán, Beatriz; Moreno Moreno, Andrés

    2014-01-01

    The thermal degradation of olive oil using conventional and microwave heating under the same experimental conditions were compared. A powerful identification and quantification technique based on 31P NMR has been developed to characterise the differences between the minor components including diacylglycerol and free fatty acids in the heated samples. The 31P NMR spectra of the degraded olive oils, which contain single bondOH groups derivatised with a phosphorus reagent, showed that convention...

  17. A Doping Lattice of Aluminum and Copper with Accelerated Electron Transfer Process and Enhanced Reductive Degradation Performance

    OpenAIRE

    Zhang, Lin; Gao, Xue; Zhang, Zhixuan; Zhang, Mingbo; Cheng, Yiqian; Su, Jixin

    2016-01-01

    Treatment of azo dye effluents has received increasing concerns over the years due to their potential harms to natural environment and human health. The present study described the degrading ability of the as-synthesized crystalline Al-Cu alloys for removal of high-concentration Acid Scarlet 3R in alkaline aqueous solutions and its degradation mechanism. Al-Cu alloy particles with Al/Cu ratios 19:1 were successfully synthesized by high-energy mechanical milling. Characterization results showe...

  18. Influence of UV dose on the UV/H2O2 process for the degradation of carbamazepine in wastewater.

    Science.gov (United States)

    Somathilake, Purnima; Dominic, John Albino; Achari, Gopal; Langford, Cooper H; Tay, Joo-Hwa

    2018-05-02

    This study evaluates the influence of UV dose on degradation of carbamazepine (CBZ) in wastewater under UV-C (λ = 254 nm) photolysis with and without H 2 O 2 . The rate of degradation of CBZ exhibited a direct dependence on the intensity of incident UV irradiation as the rate of degradation was observed to increase linearly (R 2  = 0.98) with UV intensity between 1.67 and 8.95 × 10 17 photons/s. More than 95% of the CBZ that spiked in wastewater rapidly degraded within 4 min with a first-order rate constant of 1.2 min -1 for an optimum H 2 O 2 dose of 100 mg/L. Bench-scale continuous flow reactor experiments also showed that CBZ degraded with first-order kinetics at a rate constant of 1.02 min -1 . The kinetic parameters obtained for a continuous bench-scale reactor were in good agreement with the relationships developed through batch experiments with only a marginal deviation of ± 6.5%. The relationship between UV intensity and CBZ degradation rate obtained in this study was extrapolated to the UV disinfection unit of a wastewater treatment plant to predict possible degradation of CBZ during UV disinfection. The addition of 100 mg/L of H 2 O 2 to the secondary-treated effluent entering the UV disinfection unit is predicted to achieve over 60% degradation of CBZ.

  19. Enhancing ethylbenzene vapors degradation in a hybrid system based on photocatalytic oxidation UV/TiO2–In and a biofiltration process

    International Nuclear Information System (INIS)

    Hinojosa-Reyes, M.; Rodríguez-González, V.; Arriaga, S.

    2012-01-01

    Highlights: ► The best photocatalytic system for EB degradation was based on TiO 2 –In 1%/365 nm. ► A maximum EC of 290 g m −3 h −1 for the hybrid system was obtained. ► The hybrid process enhanced 40% the overall EC of ethylbenzene. ► An overall mineralization of 67% for EB degradation was reached in the hybrid system. - Abstract: The use of hybrid processes for the continuous degradation of ethylbenzene (EB) vapors has been evaluated. The hybrid system consists of an UV/TiO 2 –In photooxidation coupled with a biofiltration process. Both the photocatalytic system using P25-Degussa or indium-doped TiO 2 catalysts and the photolytic process were performed at UV-wavelengths of 254 nm and 365 nm. The experiments were carried out in an annular plug flow photoreactor packed with granular perlite previously impregnated with the catalysts, and in a glass biofilter packed with perlite and inoculated with a microbial consortium. Both reactors were operated at an inlet loading rate of 127 g m −3 h −1 . The greatest degradation rate of EB (0.414 ng m −2 min −1 ) was obtained with the TiO 2 –In 1%/365 nm photocatalytic system. The elimination capacity (EC) obtained in the control biofilter had values ∼60 g m −3 h −1 . Consequently, the coupled system was operated for 15 days, and a maximal EC of 275 g m −3 h −1 . Thus, the results indicate that the use of hybrid processes enhanced the EB vapor degradation and that this could be a promising technology for the abatement of recalcitrant volatile organic compounds.

  20. Enhancing ethylbenzene vapors degradation in a hybrid system based on photocatalytic oxidation UV/TiO{sub 2}-In and a biofiltration process

    Energy Technology Data Exchange (ETDEWEB)

    Hinojosa-Reyes, M. [Instituto Potosino de Investigacion Cientifica y Tecnologica A.C., Division de Ciencias Ambientales, Camino a la Presa San Jose 2055, Lomas 4a seccion, CP. 78216, San Luis Potosi, S.L.P. (Mexico); Rodriguez-Gonzalez, V. [Instituto Potosino de Investigacion Cientifica y Tecnologica A.C., Division de Materiales Avanzados, Camino a la Presa San Jose 2055, Lomas 4a seccion, CP. 78216, San Luis Potosi, S.L.P. (Mexico); Arriaga, S., E-mail: sonia@ipicyt.edu.mx [Instituto Potosino de Investigacion Cientifica y Tecnologica A.C., Division de Ciencias Ambientales, Camino a la Presa San Jose 2055, Lomas 4a seccion, CP. 78216, San Luis Potosi, S.L.P. (Mexico)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer The best photocatalytic system for EB degradation was based on TiO{sub 2}-In 1%/365 nm. Black-Right-Pointing-Pointer A maximum EC of 290 g m{sup -3} h{sup -1} for the hybrid system was obtained. Black-Right-Pointing-Pointer The hybrid process enhanced 40% the overall EC of ethylbenzene. Black-Right-Pointing-Pointer An overall mineralization of 67% for EB degradation was reached in the hybrid system. - Abstract: The use of hybrid processes for the continuous degradation of ethylbenzene (EB) vapors has been evaluated. The hybrid system consists of an UV/TiO{sub 2}-In photooxidation coupled with a biofiltration process. Both the photocatalytic system using P25-Degussa or indium-doped TiO{sub 2} catalysts and the photolytic process were performed at UV-wavelengths of 254 nm and 365 nm. The experiments were carried out in an annular plug flow photoreactor packed with granular perlite previously impregnated with the catalysts, and in a glass biofilter packed with perlite and inoculated with a microbial consortium. Both reactors were operated at an inlet loading rate of 127 g m{sup -3} h{sup -1}. The greatest degradation rate of EB (0.414 ng m{sup -2} min{sup -1}) was obtained with the TiO{sub 2}-In 1%/365 nm photocatalytic system. The elimination capacity (EC) obtained in the control biofilter had values {approx}60 g m{sup -3} h{sup -1}. Consequently, the coupled system was operated for 15 days, and a maximal EC of 275 g m{sup -3} h{sup -1}. Thus, the results indicate that the use of hybrid processes enhanced the EB vapor degradation and that this could be a promising technology for the abatement of recalcitrant volatile organic compounds.

  1. Degradation mechanisms of Microcystin-LR during UV-B photolysis and UV/H2O2 processes: Byproducts and pathways.

    Science.gov (United States)

    Moon, Bo-Ram; Kim, Tae-Kyoung; Kim, Moon-Kyung; Choi, Jaewon; Zoh, Kyung-Duk

    2017-10-01

    The removal and degradation pathways of microcystin-LR (MC-LR, [M+H] +  = 995.6) in UV-B photolysis and UV-B/H 2 O 2 processes were examined using liquid chromatography-tandem mass spectrometry. The UV/H 2 O 2 process was more efficient than UV-B photolysis for MC-LR removal. Eight by-products were newly identified in the UV-B photolysis ([M+H] +  = 414.3, 417.3, 709.6, 428.9, 608.6, 847.5, 807.4, and 823.6), and eleven by-products were identified in the UV-B/H 2 O 2 process ([M+H] +  = 707.4, 414.7, 429.3, 445.3, 608.6, 1052.0, 313.4, 823.6, 357.3, 245.2, and 805.7). Most of the MC-LR by-products had lower [M+H] + values than the MC-LR itself during both processes, except for the [M+H] + value of 1052.0 during UV-B photolysis. Based on identified by-products and peak area patterns, we proposed potential degradation pathways during the two processes. Bond cleavage and intramolecular electron rearrangement by electron pair in the nitrogen atom were the major reactions during UV-B photolysis and UV-B/H 2 O 2 processes, and hydroxylation by OH radical and the adduct formation reaction between the produced by-products were identified as additional pathways during the UV-B/H 2 O 2 process. Meanwhile, the degradation by-products identified from MC-LR during UV-B/H 2 O 2 process can be further degraded by increasing H 2 O 2 dose. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Analysis of land degradation processes on a tiger bush plateau in South West Niger using MODIS and LANDSAT TM/ETM+ data

    Science.gov (United States)

    Fiorillo, Edoardo; Maselli, Fabio; Tarchiani, Vieri; Vignaroli, Patrizio

    2017-10-01

    Remote sensing digital image analysis has been applied to monitor land clearing and degradation processes on a plateau covered by tiger bush near Niamey in South West Niger, where signs of severe landscape degradation due to fuelwood supply have been observed in the last decades. A MODIS NDVI dataset (2000-2015) and five LANDSAT images (1986-2012) were used to identify spatial and temporal dynamics and to emphasize areas of greater degradation. The study indicates that the land clearing found by previous investigations in the second part of the 20th century is still ongoing, with a decreasing trend of MODIS NDVI values recorded in the period 2000-2015. This trend appeared to be linked to an increase in bare soil areas that was demonstrated by analysis of LANDSAT SAVI images. The investigation also indicated that rates of degradation are stronger in more deteriorated areas like those located nearer Niamey; degradation patterns also tend to increase from the inner areas to the edges of the plateau. These results attest to the urgency to develop effective environmental preservation policies and find alternative solutions for domestic energy supply.

  3. APEX (Aqueous Photochemistry of Environmentally occurring Xenobiotics): a free software tool to predict the kinetics of photochemical processes in surface waters.

    Science.gov (United States)

    Bodrato, Marco; Vione, Davide

    2014-04-01

    The APEX software predicts the photochemical transformation kinetics of xenobiotics in surface waters as a function of: photoreactivity parameters (direct photolysis quantum yield and second-order reaction rate constants with transient species, namely ˙OH, CO₃(-)˙, (1)O₂ and the triplet states of chromophoric dissolved organic matter, (3)CDOM*), water chemistry (nitrate, nitrite, bicarbonate, carbonate, bromide and dissolved organic carbon, DOC), and water depth (more specifically, the optical path length of sunlight in water). It applies to well-mixed surface water layers, including the epilimnion of stratified lakes, and the output data are average values over the considered water column. Based on intermediate formation yields from the parent compound via the different photochemical pathways, the software can also predict intermediate formation kinetics and overall yield. APEX is based on a photochemical model that has been validated against available field data of pollutant phototransformation, with good agreement between model predictions and field results. The APEX software makes allowance for different levels of knowledge of a photochemical system. For instance, the absorption spectrum of surface water can be used if known, or otherwise it can be modelled from the values of DOC. Also the direct photolysis quantum yield can be entered as a detailed wavelength trend, as a single value (constant or average), or it can be defined as a variable if unknown. APEX is based on the free software Octave. Additional applications are provided within APEX to assess the σ-level uncertainty of the results and the seasonal trend of photochemical processes.

  4. Effect of continuous positive airway pressure treatment for obstructive sleep apnoea on visual processing of degraded words.

    Science.gov (United States)

    Proudlove, Katie; Manuel, Ari; Hall, Rachel; Rieu, Romelie; Villarroel, Mauricio; Stradling, John

    2014-01-01

    In a previous uncontrolled study, continuous positive airway pressure (CPAP) therapy for obstructive sleep apnoea (OSA) improved vision in patients with diabetic macular oedema. We investigated whether the above improvement in vision (or visual processing) might have been due to reduced sleepiness, rather than a true improvement in retinal function. Twelve normal control subjects and 20 patients with OSA were tested for their ability to recognise degraded words, by means of a computer programme displaying 5-letter words every 4 s for 10 min, with variable amounts of the bottom half of the word missing; the percentage of the word necessary to achieve correct identification on average half the time was 'hunted' (the test score). All subjects were tested twice, 2-3 weeks apart; the OSA group after the commencement of CPAP. The Epworth Sleepiness Score (ESS) in patients was measured at the same visit. The test score at visit 1 was 26.7% for normal subjects and 31.6% for patients with OSA. At visit 2, the test score was 25.0% for normal subjects and 29.9% for patients with OSA. The groups showed a small and identical improvement over the trial period in the test score, of 1.7% (p = 0.01 and p = 0.03 for the normal and OSA groups, respectively). The group with OSA experienced a drop in ESS of 7.5 (SD 5.5) points following treatment. The small and identical improvement in both groups suggests only a similar learning effect rather than any improvement due to reduced sleepiness.

  5. Some processes of energy saving and expenditure occurring during ethanol perfusion in the isolated liver of fed rats; a Nuclear Magnetic Resonance study.

    Directory of Open Access Journals (Sweden)

    Gin Henri

    2004-03-01

    Full Text Available Abstract Background In the isolated liver of fed rats, a 10 mM ethanol perfusion rapidly induced a rapid 25% decrease in the total ATP content, the new steady state resulting from both synthesis and consumption. The in situ rate of mitochondrial ATP synthesis without activation of the respiration was increased by 27%, implying an increased energy demand. An attempt to identify the ethanol-induced ATP-consuming pathways was performed using 31P and 13C Nuclear Magnetic Resonance. Results Ethanol (i transiently increased sn-glycerol-3-phosphate formation whereas glycogenolysis was continuously maintained; (ii decreased the glycolytic ATP supply and (iii diminished the intracellular pH in a dose-dependent manner in a slight extend. Although the cytosolic oxidation of ethanol largely generated H+ (and NADH, intracellular pHi was maintained by (i the large and passive excretion of cellular acetic acid arising from ethanol oxidation (evidenced by exogenous acetate administration, without energetic cost or (ii proton extrusion via the Na+-HCO3- symport (implying the indirect activation of the Na+-K+-ATPase pump and thus an energy use, demonstrated during the addition of their specific inhibitors SITS and ouabaïn, respectively. Conclusion Various cellular mechanisms diminish the cytosolic concentration of H+ and NADH produced by ethanol oxidation, such as (i the large but transient contribution of the dihydroxyacetone phosphate / sn-glycerol-3-phosphate shuttle between cytosol and mitochondria, mainly implicated in the redox state and (ii the major participation of acetic acid in passive proton extrusion out of the cell. These processes are not ATP-consuming and the latter is a cellular way to save some energy. Their starting in conjunction with the increase in mitochondrial ATP synthesis in ethanol-perfused whole liver was however insufficient to alleviate either the inhibition of glycolytic ATP synthesis and/or the implication of Na+-HCO3- symport and

  6. Terminal processes in the anaerobic degradation of an algal-bacterial mat in a high-sulfate hot spring

    International Nuclear Information System (INIS)

    Ward, D.M.; Olson, G.J.

    1980-01-01

    The algal-bacterial mat of a high-sulfate hot spring (Bath Lake) provided an environment in which to compare terminal processes involved in anaerobic decomposition. Sulfate reduction was found to dominate methane production, as indicated by comparison of initial electron flow through the two processes, rapid conversion of [2- 14 C]acetate to 14 CO 2 and not to 14 CH 4 , and the lack of rapid reduction of NaH 14 CO 3 to 14 CH 4 . Sulfate reduction was the dominant process at all depth intervals, but a marked decrease of sulfate reduction and sulfate-reducing bacteria was observed with depth. Concurrent methanogenesis was indicated by the presence of viable methanogenic bacteria and very low but detectable rates of methane production. A marked increase in methane production was observed after sulfate depletion despite high concentrations of sulfide (>1.25 mM), indicating that methanogenesis was not inhibited by sulfide in the natural environment. Although a sulfate minimum and sulfide maximum occurred in the region of maximal sulfate reduction, the absence of sulfate depletion in interstitial water suggests that methanogenesis is always severely limited in Bath Lake sediments. Low initial methanogenesis was not due to anaerobic methane oxidation

  7. Degradation of 4-chloro 2-aminophenol using a novel combined process based on hydrodynamic cavitation, UV photolysis and ozone.

    Science.gov (United States)

    Barik, Arati J; Gogate, Parag R

    2016-05-01

    The degradation of 4-chloro 2-aminophenol (4C2AP), an acute toxic organic compound, has been studied using different approaches based on the hydrodynamic cavitation (HC) with orifice plate as cavitating device, photolysis (UV) and ozonation (O3). The dependency of extent of degradation on operating parameters like operating pressure (2-5 bar), initial pH (3-8) and temperature (30-38 °C) have been established initially to maximize the efficacy of hydrodynamic cavitation. Subsequently the degradation has been studied using combined treatment strategies as HC+UV, HC+O3, UV+O3 and HC+UV+O3 at the established optimum parameters of operating temperature as 30 °C, initial pH of 6 and inlet pressure of 4 bar. The maximum extent of degradation as 96.85% and 73.6% reduction in TOC has been obtained using hydrodynamic cavitation in combination with UV photolysis and ozonation under the optimized operating conditions. The degradation products of 4C2AP have been identified using GC-MS. The present work has clearly established the efficacy of combined treatment approach (HC+UV+O3) for the removal of organic pollutant for the first time. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Modeling Aerobic Carbon Source Degradation Processes using Titrimetric Data and Combined Respirometric-Titrimetric Data: Experimental Data and Model Structure

    DEFF Research Database (Denmark)

    Gernaey, Krist; Petersen, B.; Nopens, I.

    2002-01-01

    Experimental data are presented that resulted from aerobic batch degradation experiments in activated sludge with simple carbon sources (acetate and dextrose) as substrates. Data collection was done using combined respirometric-titrimetric measurements. The respirometer consists of an open aerated....... For acetate, protons were consumed during aerobic degradation, whereas for dextrose protons were produced. For both carbon sources, a linear relationship was found between the amount of carbon source added and the amount of protons consumed (in case of acetate: 0.38 meq/mmol) or produced (in case of dextrose...

  9. Volatile fatty acid degradation kinetics in anaerobic process; Cinetica de la degradacion de acidos grasos volatiles en procesos anaerobios

    Energy Technology Data Exchange (ETDEWEB)

    Riscado, S.; Osuna, B.; Iza, J.; Ruiz, E. [Universidad del Pais Vasco. Bilbao (Spain)

    1998-10-01

    While searching for the optimal substrate load for anaerobic toxicity assays, the inhibition caused by the propionic acid has been addressed. Lab scale experiments have been carried out to assess the effects of different loads and acid ratios. Results bad been subjected to kinetic analysis and show the degradation follows a first order kinetic, and acetic is easier to degrade than propionic acid. The optimal load for a 100 ml vial assay is composed of 158 mg COD of the 3:1:1 HAc:HPr:HBu mixture. (Author) 9 refs.

  10. Tolfenamic acid degradation by direct photolysis and the UV-ABC/H2O2 process: factorial design, kinetics, identification of intermediates, and toxicity evaluation.

    Science.gov (United States)

    de Melo da Silva, Lucas; Pereira Cavalcante, Rodrigo; Fabbro Cunha, Rebeca; Gozzi, Fábio; Falcao Dantas, Renato; de Oliveira, Silvio Cesar; Machulek, Amilcar

    2016-12-15

    This study employed direct UV-ABC photolysis and the UV-ABC/H 2 O 2 process to investigate the degradation of tolfenamic acid (TA), a common anti-inflammatory drug used in both human and veterinary medicine. A 2 3 factorial design with added center point was used to evaluate the effect of three independent variables-namely, H 2 O 2 concentration ([H 2 O 2 ]), TA concentration ([TA]), and experiment time (time)-on TA degradation and H 2 O 2 photolysis during UV-ABC/H 2 O 2 treatment using a high-pressure mercury vapor lamp (photon flux of 2.6307 × 10 4 J s -1 ) as the UV irradiation source. The responses yielded similar values, revealing a linear behavior, with correlation coefficients R = 0.9968 and R adj = 0.9921 for TA degradation and R = 0.9828 and R adj = 0.9570 for H 2 O 2 photolysis. The most efficient combination of variables was [H 2 O 2 ] = 255 mg L -1 and [TA] = 25 mg L -1 , resulting in 100% TA degradation and 98.87% H 2 O 2 photolysis by 90 min of treatment. Additionally, the second-order kinetic constant of the reaction between TA and HO ● was determined using a competitive kinetic model, employing 2,4-dichlorophenoxyacetic acid (2,4D) as the reference compound. The kinetic constant was 1.9 × 10 10 M -1 s -1 in alkaline medium. TA degradation by direct photolysis generated quinone imines as by-products, responsible for the formation of a dark red "internal filter" that increased the value of acute toxicity to Artemia salina. The UV-ABC/H 2 O 2 process did not promote formation of quinone imines by 90 min of treatment and therefore did not increase acute toxicity values. Several by-products generated during TA degradation were identified and possible degradation pathways for the UV-ABC and UV-ABC/H 2 O 2 processes were proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Effects of rumen-degradable protein:rumen-undegradable protein ratio and corn processing on production performance, nitrogen efficiency, and feeding behavior of Holstein dairy cows.

    Science.gov (United States)

    Savari, M; Khorvash, M; Amanlou, H; Ghorbani, G R; Ghasemi, E; Mirzaei, M

    2018-02-01

    This study was conducted to investigate the effects of the ratio of rumen-degradable protein (RDP) to rumen-undegradable protein (RUP) and corn processing method on production performance, nitrogen (N) efficiency, and feeding behavior of high-producing Holstein dairy cows. Twelve multiparous Holstein cows (second parity; milk yield = 48 ± 3 kg/d) were assigned to a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Factor 1 was corn processing method [ground corn (GC) or steam flaked corn (SFC) with a flake density of about 390 g/L], and factor 2 was RDP:RUP ratio [low ratio (LR) = 60:40; high ratio (HR) = 65:35] based on crude protein (%). The crude protein concentrations were kept constant across the treatments (16.7% of DM). No significant interactions of main treatment effects occurred for lactation performance data. Cows fed 2 different RDP:RUP ratios exhibited similar dry matter intake (DMI), but those fed SFC showed decreased feed intake compared with those receiving GC (25.1 ± 0.48 vs. 26.2 ± 0.47 kg/d, respectively). Cows fed HR diets produced more milk than did those fed LR diets (44.4 ± 1.05 vs. 43.2 ± 1.05 kg/d, respectively). Milk fat content decreased but milk protein content increased in cows fed SFC compared with those fed GC. Feed efficiency (i.e., milk yield/DMI) was enhanced with increasing ratio of RDP:RUP (1.68 ± 0.04 vs. 1.74 ± 0.04 for LR and HR, respectively). Apparent N efficiency was higher in cows fed HR than in those fed LR (30.4 ± 0.61 vs. 29.2 ± 0.62, respectively). Compared with cows fed the GC-based diet, those receiving SFC exhibited lower values of N intake, N-NH 3 concentration, and fecal N excretion. Cows receiving SFC-based diets spent more time ruminating (min/kg of DMI) than did those fed GC. Although these results showed no interaction effects of RDP:RUP ratio and corn processing method on performance, higher RDP:RUP ratios and ground corn can be effective feeding strategies for

  12. Solar photo-Fenton process on the abatement of antibiotics at a pilot scale: Degradation kinetics, ecotoxicity and phytotoxicity assessment and removal of antibiotic resistant enterococci.

    Science.gov (United States)

    Michael, I; Hapeshi, E; Michael, C; Varela, A R; Kyriakou, S; Manaia, C M; Fatta-Kassinos, D

    2012-11-01

    This work investigated the application of a solar driven advanced oxidation process (solar photo-Fenton), for the degradation of antibiotics at low concentration level (μg L(-1)) in secondary treated domestic effluents at a pilot-scale. The examined antibiotics were ofloxacin (OFX) and trimethoprim (TMP). A compound parabolic collector (CPC) pilot plant was used for the photocatalytic experiments. The process was mainly evaluated by a fast and reliable analytical method based on a UPLC-MS/MS system. Solar photo-Fenton process using low iron and hydrogen peroxide doses ([Fe(2+)](0) = 5 mg L(-1); [H(2)O(2)](0) = 75 mg L(-1)) was proved to be an efficient method for the elimination of these compounds with relatively high degradation rates. The photocatalytic degradation of OFX and TMP with the solar photo-Fenton process followed apparent first-order kinetics. A modification of the first-order kinetic expression was proposed and has been successfully used to explain the degradation kinetics of the compounds during the solar photo-Fenton treatment. The results demonstrated the capacity of the applied advanced process to reduce the initial wastewater toxicity against the examined plant species (Sorghum saccharatum, Lepidium sativum, Sinapis alba) and the water flea Daphnia magna. The phytotoxicity of the treated samples, expressed as root growth inhibition, was higher compared to that observed on the inhibition of seed germination. Enterococci, including those resistant to OFX and TMP, were completely eliminated at the end of the treatment. The total cost of the full scale unit for the treatment of 150 m(3) day(-1) of secondary wastewater effluent was found to be 0.85 € m(-3). Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Spatial profiling of degradation processes in hindered-amine-stabilized polymers by electron spin resonance imaging of nitroxides

    Czech Academy of Sciences Publication Activity Database

    Marek, Antonín; Kaprálková, Ludmila; Pfleger, Jiří; Pospíšil, Jan; Pilař, Jan

    2005-01-01

    Roč. 99, S (2005), s. 195-198 ISSN 0009-2770. [Meeting on Chemistry and Life /3./. Brno, 20.9.2005-22.9.2005] Institutional research plan: CEZ:AV0Z40500505 Keywords : polymer degradation * nitroxides * electron spin resonance imaging Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.445, year: 2005

  14. Thermo-oxidative degradation study of melt-processed polyethylene and its blend with polyamide using time-resolved rheometry

    CSIR Research Space (South Africa)

    Salehiyan, Reza

    2017-05-01

    Full Text Available Time-resolved mechanical spectroscopy (TRMS) was conducted to study the thermo-oxidative degradation of linear low density polyethylene (LLDPE) samples with different thermal histories and their blends with a polyamide (PA6) in the melt state. Neat...

  15. Complex degradation processes lead to non-exponential decay patterns and age-dependent decay rates of messenger RNA.

    Directory of Open Access Journals (Sweden)

    Carlus Deneke

    Full Text Available Experimental studies on mRNA stability have established several, qualitatively distinct decay patterns for the amount of mRNA within the living cell. Furthermore, a variety of different and complex biochemical pathways for mRNA degradation have been identified. The central aim of this paper is to bring together both the experimental evidence about the decay patterns and the biochemical knowledge about the multi-step nature of mRNA degradation in a coherent mathematical theory. We first introduce a mathematical relationship between the mRNA decay pattern and the lifetime distribution of individual mRNA molecules. This relationship reveals that the mRNA decay patterns at steady state expression level must obey a general convexity condition, which applies to any degradation mechanism. Next, we develop a theory, formulated as a Markov chain model, that recapitulates some aspects of the multi-step nature of mRNA degradation. We apply our theory to experimental data for yeast and explicitly derive the lifetime distribution of the corresponding mRNAs. Thereby, we show how to extract single-molecule properties of an mRNA, such as the age-dependent decay rate and the residual lifetime. Finally, we analyze the decay patterns of the whole translatome of yeast cells and show that yeast mRNAs can be grouped into three broad classes that exhibit three distinct decay patterns. This paper provides both a method to accurately analyze non-exponential mRNA decay patterns and a tool to validate different models of degradation using decay data.

  16. Mechanistic Insight into the Elastin Degradation Process by the Metalloprotease Myroilysin from the Deep-Sea Bacterium Myroides profundi D25

    Science.gov (United States)

    Yang, Jie; Zhao, Hui-Lin; Tang, Bai-Lu; Chen, Xiu-Lan; Su, Hai-Nan; Zhang, Xi-Ying; Song, Xiao-Yan; Zhou, Bai-Cheng; Xie, Bin-Bin; Weiss, Anthony S.; Zhang, Yu-Zhong

    2015-01-01

    Elastases have been widely studied because of their important uses as medicine and meat tenderizers. However, there are relatively few studies on marine elastases. Myroilysin, secreted by Myroides profundi D25 from deep-sea sediment, is a novel elastase. In this study, we examined the elastin degradation mechanism of myroilysin. When mixed with insoluble bovine elastin, myroilysin bound hydrophobically, suggesting that this elastase may interact with the hydrophobic domains of elastin. Consistent with this, analysis of the cleavage pattern of myroilysin on bovine elastin and recombinant tropoelastin revealed that myroilysin preferentially cleaves peptide bonds with hydrophobic residues at the P1 and/or P1′ positions. Scanning electron microscopy (SEM) of cross-linked recombinant tropoelastin degraded by myroilysin showed preferential damages of spherules over cross-links, as expected for a hydrophobic preference. The degradation process of myroilysin on bovine elastin fibres was followed by light microscopy and SEM, revealing that degradation begins with the formation of crevices and cavities at the fibre surface, with these openings increasing in number and size until the fibre breaks into small pieces, which are subsequently fragmented. Our results are helpful for developing biotechnological applications for myroilysin. PMID:25793427

  17. Mechanistic Insight into the Degradation of Nitrosamines via Aqueous-Phase UV Photolysis or a UV-Based Advanced Oxidation Process: Quantum Mechanical Calculations

    Directory of Open Access Journals (Sweden)

    Daisuke Minakata

    2018-02-01

    Full Text Available Nitrosamines are a group of carcinogenic chemicals that are present in aquatic environments that result from byproducts of industrial processes and disinfection products. As indirect and direct potable reuse increase, the presence of trace nitrosamines presents challenges to water infrastructures that incorporate effluent from wastewater treatment. Ultraviolet (UV photolysis or UV-based advanced oxidation processes that produce highly reactive hydroxyl radicals are promising technologies to remove nitrosamines from water. However, complex reaction mechanisms involving radicals limit our understandings of the elementary reaction pathways embedded in the overall reactions identified experimentally. In this study, we perform quantum mechanical calculations to identify the hydroxyl radical-induced initial elementary reactions with N-nitrosodimethylamine (NDMA, N-nitrosomethylethylamine, and N-nitrosomethylbutylamine. We also investigate the UV-induced NDMA degradation mechanisms. Our calculations reveal that the alkyl side chains of nitrosamine affect the reaction mechanism of hydroxyl radicals with each nitrosamine investigated in this study. Nitrosamines with one- or two-carbon alkyl chains caused the delocalization of the electron density, leading to slower subsequent degradation. Additionally, three major initial elementary reactions and the subsequent radical-involved reaction pathways are identified in the UV-induced NDMA degradation process. This study provides mechanistic insight into the elementary reaction pathways, and a future study will combine these results with the kinetic information to predict the time-dependent concentration profiles of nitrosamines and their transformation products.

  18. Mechanistic Insight into the Degradation of Nitrosamines via Aqueous-Phase UV Photolysis or a UV-Based Advanced Oxidation Process: Quantum Mechanical Calculations.

    Science.gov (United States)

    Minakata, Daisuke; Coscarelli, Erica

    2018-02-28

    Nitrosamines are a group of carcinogenic chemicals that are present in aquatic environments that result from byproducts of industrial processes and disinfection products. As indirect and direct potable reuse increase, the presence of trace nitrosamines presents challenges to water infrastructures that incorporate effluent from wastewater treatment. Ultraviolet (UV) photolysis or UV-based advanced oxidation processes that produce highly reactive hydroxyl radicals are promising technologies to remove nitrosamines from water. However, complex reaction mechanisms involving radicals limit our understandings of the elementary reaction pathways embedded in the overall reactions identified experimentally. In this study, we perform quantum mechanical calculations to identify the hydroxyl radical-induced initial elementary reactions with N -nitrosodimethylamine (NDMA), N -nitrosomethylethylamine, and N -nitrosomethylbutylamine. We also investigate the UV-induced NDMA degradation mechanisms. Our calculations reveal that the alkyl side chains of nitrosamine affect the reaction mechanism of hydroxyl radicals with each nitrosamine investigated in this study. Nitrosamines with one- or two-carbon alkyl chains caused the delocalization of the electron density, leading to slower subsequent degradation. Additionally, three major initial elementary reactions and the subsequent radical-involved reaction pathways are identified in the UV-induced NDMA degradation process. This study provides mechanistic insight into the elementary reaction pathways, and a future study will combine these results with the kinetic information to predict the time-dependent concentration profiles of nitrosamines and their transformation products.

  19. Enhanced degradation of azo dye alizarin yellow R in a combined process of iron-carbon microelectrolysis and aerobic bio-contact oxidation.

    Science.gov (United States)

    Liang, Bin; Yao, Qian; Cheng, Haoyi; Gao, Shuhong; Kong, Fanying; Cui, Dan; Guo, Yuqi; Ren, Nanqi; Lee, Duu-Jong; Wang, Aijie

    2012-06-01

    With the aim of enhanced degradation of azo dye alizarin yellow R (AY) and further removal of the low-strength recalcitrant matter (LsRM) of the secondary effluent as much as possible, our research focused on the combination of aerobic bio-contact oxidation (ABO) with iron/carbon microelectrolysis (ICME) process. The combined ABO (with effective volume of 2.4 l) and ICME (with effectively volume of 0.4 l) process were studied with relatively short hydraulic retention time (HRT) of 4 or 6 h. At the HRT of 6 h with the reflux ratio of 1 and 2, the AY degradation efficiency in the final effluent was >96.5%, and the total organic carbon (TOC) removal efficiency were 69.86% and 79.44%, respectively. At the HRT of 4 h and the reflux ratio of 2, TOC removal efficiency and AY degradation efficiency were 73.94% and 94.89%, respectively. The ICME process obviously enhanced the total AY removal and the generated micromolecule acids and aldehydes then that wastewater backflow to the ABO where they were further biodegraded. The present research might provide the potential options for the advanced treatment azo dyes wastewater with short HRT and acceptable running costs.

  20. Solar degradation of diclofenac using Eosin-Y-activated TiO2: cost estimation, process optimization and parameter interaction study.

    Science.gov (United States)

    Hashim, Noshin; Thakur, Shaila; Patang, Mouska; Crapulli, Ferdinando; Ray, Ajay K

    2017-04-01

    Diclofenac (DCF), a widely used non-steroidal anti-inflammatory drug, is a commonly detected substance that readily accumulates in tissues of aquatic fish and poses a threat to wildlife and freshwater quality. Advanced Oxidation Processes have been employed as an alternative due to the inadequacy of conventional treatment methods of trace contaminants. This study utilized an innovative method of solar-activation of TiO 2 using Eosin-Y dye for the degradation of DCF. Furthermore, the study incorporated a central composite design (CCD) to optimize the dye concentration and estimated the cost for the present process. Optimized parameters for light intensity (750 mW/cm 2 ), Eosin-Y dye concentration (2 mg/L), TiO 2 loading (37.5 mg/cm 2 ) and DCF concentration (25 mg/L) were determined through a CCD. The optimized parameters convey a DCF degradation rate of 40% and 49% for 2 ppm (low range) and 4 ppm (high range) dye concentrations, respectively, for a 5-minute reaction time. Cost estimation for the materials used was for the current process was also performed. It was determined that the additional cost of using 4 ppm instead of 2 ppm to achieve only 10% more DCF degradation is not warranted and would require additional treatment to remove subsequently formed halogenated compounds.

  1. Naturally Occurring Radioactive Materials (NORM)

    International Nuclear Information System (INIS)

    Gray, P.

    1997-01-01

    This paper discusses the broad problems presented by Naturally Occuring Radioactive Materials (NORM). Technologically Enhanced naturally occuring radioactive material includes any radionuclides whose physical, chemical, radiological properties or radionuclide concentration have been altered from their natural state. With regard to NORM in particular, radioactive contamination is radioactive material in an undesired location. This is a concern in a range of industries: petroleum; uranium mining; phosphorus and phosphates; fertilizers; fossil fuels; forestry products; water treatment; metal mining and processing; geothermal energy. The author discusses in more detail the problem in the petroleum industry, including the isotopes of concern, the hazards they present, the contamination which they cause, ways to dispose of contaminated materials, and regulatory issues. He points out there are three key programs to reduce legal exposure and problems due to these contaminants: waste minimization; NORM assesment (surveys); NORM compliance (training)

  2. Naturally Occurring Radioactive Materials (NORM)

    Energy Technology Data Exchange (ETDEWEB)

    Gray, P. [ed.

    1997-02-01

    This paper discusses the broad problems presented by Naturally Occuring Radioactive Materials (NORM). Technologically Enhanced naturally occuring radioactive material includes any radionuclides whose physical, chemical, radiological properties or radionuclide concentration have been altered from their natural state. With regard to NORM in particular, radioactive contamination is radioactive material in an undesired location. This is a concern in a range of industries: petroleum; uranium mining; phosphorus and phosphates; fertilizers; fossil fuels; forestry products; water treatment; metal mining and processing; geothermal energy. The author discusses in more detail the problem in the petroleum industry, including the isotopes of concern, the hazards they present, the contamination which they cause, ways to dispose of contaminated materials, and regulatory issues. He points out there are three key programs to reduce legal exposure and problems due to these contaminants: waste minimization; NORM assesment (surveys); NORM compliance (training).

  3. Mechanochemical degradation of potato starch paste under ultrasonic irradiation

    Institute of Scientific and Technical Information of China (English)

    LI Jian-bin; LI Lin; LI Bing; CHEN Ling; GUI Lin

    2006-01-01

    In the paper, changes in the molecular weight, the intrinsic viscosity and the polydispersity (molecular mass distribution) of treated potato starch paste were studied under different ultrasonic conditions which include irradiation time, ultrasonic intensity, potato starch paste concentration, and distance from probe tip on the degradation of potato starch paste. Intrinsic viscosity of potato starch paste was determined following the ASTM (American Society for Testing and Materials) standard practice for dilute solution viscosity of polymers. Molecular mass and polydispersity of potato starch paste were measured on GPC (Gel Permeation Chromatography). The results showed that the average molecular mass and the intrinsic viscosity of starch strongly depended on irradiation time. Degradation increased with prolonged ultrasonic irradiation time, and the increase of ultrasonic intensity could accelerate the degradation, resulting in a faster degradation rate, a lower limiting value and a higher degradation extent. Starch samples were degraded faster in dilute solutions than in concentrated solutions. The molecular mass and the intrinsic viscosity of starch increased with the increase of distance from probe tip. Our results also showed that the polydispersity decreased with ultrasonic irradiation under all ultrasonic conditions. Ultrasonic degradation of potato starch paste occured based on the mechanism of molecular relaxation of starch paste. In the initial stage, ultrasonic degradation of potato starch paste was a random process, and the molecular mass distribution was broad. After that, ultrasonic degradation of potato starch paste changed to a nonrandom process, and the molecular mass distribution became narrower. Finally, molecular mass distribution tended toward a saturation value.

  4. Degradation of lipid regulators by the UV/chlorine process: Radical mechanisms, chlorine oxide radical (ClO•)-mediated transformation pathways and toxicity changes.

    Science.gov (United States)

    Kong, Xiujuan; Wu, Zihao; Ren, Ziran; Guo, Kaiheng; Hou, Shaodong; Hua, Zhechao; Li, Xuchun; Fang, Jingyun

    2018-06-15

    Degradation of three lipid regulators, i.e., gemfibrozil, bezafibrate and clofibric acid, by a UV/chlorine treatment was systematically investigated. The chlorine oxide radical (ClO • ) played an important role in the degradation of gemfibrozil and bezafibrate with second-order rate constants of 4.2 (±0.3) × 10 8  M -1  s -1 and 3.6 (±0.1) × 10 7  M -1  s -1 , respectively, whereas UV photolysis and the hydroxyl radical (HO • ) mainly contributed to the degradation of clofibric acid. The first-order rate constants (k') for the degradation of gemfibrozil and bezafibrate increased linearly with increasing chlorine dosage, primarily due to the linear increase in the ClO • concentration. The k' values for gemfibrozil, bezafibrate, and clofibric acid degradation decreased with increasing pH from 5.0 to 8.4; however, the contribution of the reactive chlorine species (RCS) increased. Degradation of gemfibrozil and bezafibrate was enhanced in the presence of Br - , whereas it was inhibited in the presence of natural organic matter (NOM). The presence of ammonia at a chlorine: ammonia molar ratio of 1:1 resulted in decreases in the k' values for gemfibrozil and bezafibrate of 69.7% and 7%, respectively, but led to an increase in that for clofibric acid of 61.8%. Degradation of gemfibrozil by ClO • was initiated by hydroxylation and chlorine substitution on the benzene ring. Then, subsequent hydroxylation, bond cleavage and chlorination reactions led to the formation of more stable products. Three chlorinated intermediates were identified during ClO • oxidation process. Formation of the chlorinated disinfection by-products chloral hydrate and 1,1,1-trichloropropanone was enhanced relative to that of other by-products. The acute toxicity of gemfibrozil to Vibrio fischeri increased significantly when subjected to direct UV photolysis, whereas it decreased when oxidized by ClO • . This study is the first to report the transformation pathway of a

  5. Effect of Rapid Thermal Processing on Light-Induced Degradation of Carrier Lifetime in Czochralski p-Type Silicon Bare Wafers

    Science.gov (United States)

    Kouhlane, Y.; Bouhafs, D.; Khelifati, N.; Belhousse, S.; Menari, H.; Guenda, A.; Khelfane, A.

    2016-11-01

    The electrical properties of Czochralski silicon (Cz-Si) p-type boron-doped bare wafers have been investigated after rapid thermal processing (RTP) with different peak temperatures. Treated wafers were exposed to light for various illumination times, and the effective carrier lifetime ( τ eff) measured using the quasi-steady-state photoconductance (QSSPC) technique. τ eff values dropped after prolonged illumination exposure due to light-induced degradation (LID) related to electrical activation of boron-oxygen (BO) complexes, except in the sample treated with peak temperature of 785°C, for which the τ eff degradation was less pronounced. Also, a reduction was observed when using the 830°C peak temperature, an effect that was enhanced by alteration of the wafer morphology (roughness). Furthermore, the electrical resistivity presented good stability under light exposure as a function of temperature compared with reference wafers. Additionally, the optical absorption edge shifted to higher wavelength, leading to increased free-carrier absorption by treated wafers. Moreover, a theoretical model is used to understand the lifetime degradation and regeneration behavior as a function of illumination time. We conclude that RTP plays an important role in carrier lifetime regeneration for Cz-Si wafers via modification of optoelectronic and structural properties. The balance between an optimized RTP cycle and the rest of the solar cell elaboration process can overcome the negative effect of LID and contribute to achievement of higher solar cell efficiency and module performance.

  6. Degradation of direct yellow 9 by electro-Fenton: process study and optimization and, monitoring of treated water toxicity using catalase.

    Science.gov (United States)

    Kourdali, Sidali; Badis, Abdelmalek; Boucherit, Ahmed

    2014-12-01

    The present study was undertaken to investigate the degradation and removal of direct yellow 9 (DY9) by the electro-Fenton (EF) process in batch reactor using iron and stainless steel electrodes. DY9 removal decreased with the increase in pH (3 to 8) and increased with the increase in current intensity (0.05 to 0.2A) and [H2O2] (0 to 0.5gL(-1), but not with high doses which led to low rates of DY9 removal and OH(∙) uptake). The regression quadratic models describing DY9 degradation yield "R (percent)" and electrical energy consumption "EEC (kWhkg(-1))" were validated by the analysis of variance (ANOVA) and were both noted to fit well with the experimental data. The R(2) correlation coefficients (0.995, 0.978), those adjusted coefficients (0.986, 0.939), and F values (110.7, 24.9) obtained for the responses validated the efficiency of model. The results revealed that among several other parameters, EEC depended essentially on the degradation yield. The eco-toxicity tests showed a positive correlation between catalase activity and DY9 concentration, and catalase could be qualitatively identified to assess the effect of dye and its by-products generated during the EF process. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. The Science of Battery Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, John P. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Physics; El Gabaly Marquez, Farid [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Physics; McCarty, Kevin [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Physics; Sugar, Joshua Daniel [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Physics; Talin, Alec A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Materials Physics; Fenton, Kyle R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Power Sources Design and Development; Nagasubramanian, Ganesan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Power Sources Design and Development; Harris, Charles Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanosystems Synthesis/Analysis; Jungjohann, Katherine Leigh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanosystems Synthesis/Analysis; Hayden, Carl C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Chemistry Dept.; Kliewer, Christopher Jesse [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Combustion Chemistry Dept.; Hudak, Nicholas S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Power Sources Research and Development; Leung, Kevin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanostructure Physics; McDaniel, Anthony H. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Hydrogen and Combustion Technology; Tenney, Craig M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Chemical and Biological Systems; Zavadil, Kevin R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Materials Lab.

    2015-01-01

    changes little with degradation but the origin of degradation in cathodes is kinetic in nature, i.e. lower rate cycling recovers lost capacity. Finally, our modeling of electrode-electrolyte interfaces revealed that electrolyte degradation may occur by either a single or double electron transfer process depending on thickness of the solid-electrolyte-interphase layer, and this cross-over can be modeled and predicted.

  8. Rapid degradation of abnormal proteins in vacuoles from Acer pseudoplatanus L. cells

    International Nuclear Information System (INIS)

    Canut, H.; Alibert, G.; Carrasco, A.; Boudet, A.M.

    1986-01-01

    In Acer pseudoplatanus cells, the proteins synthesized in the presence of an amino acid analog ([ 14 C]p-fluorophenylalanine), were degraded more rapidly than normal ones ([ 14 C]phenylalanine as precursor). The degradation of an important part of these abnormal proteins occurred inside the vacuoles. The degradation process was not apparently associated to a specific proteolytic system but was related to a preferential transfer of these aberrant proteins from the cytoplasm to the vacuole

  9. Determination of pharmacokinetic processes in body organs on the basis of the box model and, by analogy, of laws of radioactive disintegration of naturally occurring and artificially activated isotope families

    International Nuclear Information System (INIS)

    Rauser, P.

    1992-01-01

    The research work described is based on the simple law of degradation and disintegration for pharmaceutical substances. The transport, storage and, possibly, accumulation of beneficial and harmful pharmaceuticals in the organs of the human body are analysed using the box model. The studies are not restricted to asymptotic conditions occurring after continuous treatment with a particular drug but also investigate into the so-called stabilisation phase immediately after the beginning of medication, which is described mathematically. This phase is shown to be subject to a set of rules that are much more complex than those responsible for asymptotic substance levels. The analytical procedures used here are described on the basis of typical cases drawn from medical practice. The laws derived from these observations can, by analogy, also be applied to the radioactive disintegration of isotope families. They also permit formulas to be determined for the activity of multiple-link chain members. The report proceeds by discussing cases, where the baseline substance is the result of nuclear chain reacting. The last issue to be treated within the scope of this study is the radioactive disintegration and simultaneous activation of isotope families. (orig./MG) [de

  10. Quantitation of chlorophylls and 22 of their colored degradation products in culinary aromatic herbs by HPLC-DAD-MS and correlation with color changes during the dehydration process.

    Science.gov (United States)

    Lafeuille, Jean-Louis; Lefèvre, Stéphane; Lebuhotel, Julie

    2014-02-26

    Chlorophylls and their green and olive-brown derivatives were successfully separated from culinary herb extracts by HPLC with photodiode-array and mass spectrometry detection. The method involved a ternary gradient elution and reverse-phase separation conditions capable of resolving 24 different pigments (2 chlorophylls and 22 of their derivatives) of different polarities within 28 min. The method was applied to monitor color changes in 50 samples of culinary aromatic herbs subjected to five different drying treatments. Of the 24 pigments, 14 were key to understanding the differences between the primary degradation pathways of chlorophyll a and chlorophyll b in culinary herbs during drying processes. A color degradation ladder based on the total molar percentage of all the remaining green pigments was also proposed as a tool to measure the impact of drying treatments on aromatic herb visual aspects.

  11. Insights into the processes behind the contamination of degraded human teeth and bone samples with exogenous sources of DNA

    DEFF Research Database (Denmark)

    Gilbert, M. T. P.; Hansen, Anders J.; Willerslev, E.

    2006-01-01

    A principal problem facing human DNA studies that use old and degraded remains is contamination from other sources of human DNA. In this study we have attempted to contaminate deliberately bones and teeth sampled from a medieval collection excavated in Trondheim, Norway, in order to investigate......, prior to assaying for the residual presence of the handler's DNA. Surprisingly, although our results suggest that a large proportion of the teeth were contaminated with multiple sources of human DNA prior to our investigation, we were unable to contaminate the samples with further human DNA. One...

  12. Modelling sulfamethoxazole degradation under different redox conditions

    Science.gov (United States)

    Sanchez-Vila, X.; Rodriguez-Escales, P.

    2015-12-01

    Sulfamethoxazole (SMX) is a low adsorptive, polar, sulfonamide antibiotic, widely present in aquatic environments. Degradation of SMX in subsurface porous media is spatially and temporally variable, depending on various environmental factors such as in situ redox potential, availability of nutrients, local soil characteristics, and temperature. It has been reported that SMX is better degraded under anoxic conditions and by co-metabolism processes. In this work, we first develop a conceptual model of degradation of SMX under different redox conditions (denitrification and iron reducing conditions), and second, we construct a mathematical model that allows reproducing different experiments of SMX degradation reported in the literature. The conceptual model focuses on the molecular behavior and contemplates the formation of different metabolites. The model was validated using the experimental data from Barbieri et al. (2012) and Mohatt et al. (2011). It adequately reproduces the reversible degradation of SMX under the presence of nitrite as an intermediate product of denitrification. In those experiments degradation was mediated by the transient formation of a diazonium cation, which was considered responsible of the substitution of the amine radical by a nitro radical, forming the 4-nitro-SMX. The formation of this metabolite is a reversible process, so that once the concentration of nitrite was back to zero due to further advancement of denitrification, the concentration of SMX was fully recovered. The forward reaction, formation of 4-nitro SMX, was modeled considering a kinetic of second order, whereas the backward reaction, dissociation of 4-nitro-SMX back to the original compound, could be modeled with a first order degradation reaction. Regarding the iron conditions, SMX was degraded due to the oxidation of iron (Fe2+), which was previously oxidized from goethite due to the degradation of a pool of labile organic carbon. As the oxidation of iron occurred on the

  13. Enhancement of Fenton and photo-Fenton processes at initial circumneutral pH for the degradation of the β-blocker metoprolol.

    Science.gov (United States)

    Romero, V; Acevedo, S; Marco, P; Giménez, J; Esplugas, S

    2016-01-01

    The need for acidification in the Fenton and photo-Fenton process is often outlined as one of its major drawbacks, thus in this work the acidification of the Metoprolol (MET) is avoided by the addition of resorcinol (RES), which is used to simulate model organic matter. The experiments were carried out at natural pH (6.2) with different Fe(2+) (1, 2.5, 5, and 10 mg/L) and H2O2 (25, 50, 125 and 150 mg/L) concentrations. The performance of MET and RES degradation was assessed along the reaction time. Working with the highest concentrations (5 and 10 mg/L of ferrous iron and 125 and 150 mg/L of H2O2) more than 90% of MET and RES removals were reached within 50 and 20 min of treatment, respectively, by Fenton process. However a low mineralization was achieved in both cases, likely, due to by-products accumulation. Regarding to photo-Fenton process, within 3 min with the highest iron and hydrogen peroxide concentrations, a complete MET degradation was obtained and 95% of RES conversion was achieved. Parameters such Total Organic Carbon, Chemical Oxygen Demand, and AOS were measured. Intermediates were identified and MET degradation path was proposed in the presence of resorcinol. Finally, a comparison between Fenton and photo-Fenton processes at acid pH and at initial circumneutral pH was discussed. The positive effect of RES on Fenton and photo-Fenton systems has been confirmed, allowing the work at circumneutral pH. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Bifunctional composite from spent "Cyprus coffee" for tetracycline removal and phenol degradation: Solar-Fenton process and artificial neural network.

    Science.gov (United States)

    Oladipo, Akeem Adeyemi; Abureesh, Mosab Ali; Gazi, Mustafa

    2016-09-01

    Removals of tetracycline and photocatalytic degradation of phenol by Fe3O4/coffee residue (MCC) were investigated. Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM) and Boehm titration were employed to characterize MCC. Artificial neural network (ANN) model was developed to predict the tetracycline (TC) concentration in the column effluent. Maximum tetracycline adsorption capacity of 285.6mg/g was observed in a batch system. High removal efficiency (87%) was obtained at 3.3mL/min flow rate, 8.0cm bed height and 50mg/L influent TC concentration in a column system. Complete degradation of phenol by solar-Fenton was attained at 60min irradiation time. Total organic carbon (TOC) removal increased to 63.3% in the presence of 1.0g/L MCC, 1.2g/L H2O2 and solar irradiation. MCC showed remarkable potential to remove antibiotics from wastewater even in the presence of heavy metal (Ni(2+)) via magnetic separation. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Study of oil diesel degradation in soil using oxidative advanced processes; Estudo da degradacao do oleo diesel em solo utilizando processos oxidativos avancados

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Suenia S.; Silva, Valdinete L. da; Motta, Mauricio da [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Quimica; Silva, Paula Tereza de S. e; Barros Neto, Benicio de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Quimica Fundamental

    2004-07-01

    Recently it comes if observing several accidents during the exploration, refinement, transport and operation of storage of petroleum and yours derived, such as the diesel oil and the gasoline. In this paper We do a study of the degradation of the diesel oil in a characteristic soil of the state of Pernambuco using peroxide of hydrogen and Fenton reagent. Those two processes are based on the generation of the radical hydroxyl (OH.) that has to can oxidizer loud capable to promote the destruction of recalcitrant organic compositions. The studied soil has about 16,5{+-}0,3 g/kg of total organic carbon. A factorial planning was accomplished 2{sup 3} with 2 repetitions in the central point with the objective of finding the best conditions of degradation of the pollutant. The variables and the studied levels were: FeSO{sub 4} - 0,18 M (0, 4 and 8 Ml); pH (3; without adjustment and without adjustment) and Time of exhibition in the sun (8; 12 and 16:00). The volumes of H{sub 2}O{sub 2} used in the rehearsals were constant, being 80 mL. Soon afterwards it accomplished a fractional experimental planning 2{sup 3-1}, repeating the variables of the first planning, they put using a smaller volume of H{sub 2}O{sub 2}, 40 mL, to evaluate the influence of the amount of H{sub 2}O{sub 2} used about the degradation of the diesel oil. The mass of the soil used in each experiment was of 5 g. It was observed that there were not significant differences in the degradation in relation to the peroxide volume. The best found degradation was around 87% in the following conditions (4 mL of Faith, without pH adjustment, Time of exhibition in the sun of 12:00 and 80 ml of H{sub 2}O{sub 2}). That found degradation was quite satisfactory being still due to study more economical conditions. (author)

  16. Degradation and COD removal of catechol in wastewater using the catalytic ozonation process combined with the cyclic rotating-bed biological reactor.

    Science.gov (United States)

    Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

    2015-07-01

    The effect of ozonation catalyzed with MgO/granular activated carbon (MgO/GAC) composite as a pretreatment process on the performance of cyclic rotating-bed biological reactor (CRBR) for the catechol removal from wastewater has been investigated. CRBR with acclimated biomasses could efficiently remove catechol and its related COD from wastewater at organic loading rate (OLR) of 7.82 kg COD/m(3).d (HRT of 9 h). Then, OLR increased to 15.64 kg COD/m(3).d (HRT of 4.5 h) and CRBR failed. Catalytic ozonation process (COP) used as a pre-treatment and could improve the performance of the failed CRBR. The overall removal efficiency of the combined process attained respective steady states of 91% and 79% for degradation and COD removal of catechol. Therefore, the combined process is more effective in degradation and COD removal of catechol; it is also a viable alternative for upgrading industrial wastewater treatment plant. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Effect of ensiling process of total mixed ration on fermentation profile, nutrient loss and in situ ruminal degradation characteristics of diet.

    Science.gov (United States)

    Miyaji, Makoto; Matsuyama, Hiroki; Nonaka, Kazuhisa

    2017-01-01

    This experiment aimed to determine the changes in chemical composition, fermentation profile, in situ disappearance characteristics, and nutrient losses of ensiled total mixed ration (TMR) containing steam-flaked corn or brown rice (BR) during storage. TMRs for dairy cows, containing either steam-flaked corn or BR at 31.9% with 15.2% rye silage, 40.5% alfalfa silage, 5.0% beet pulp and 7.0% soybean meal, were prepared (dry matter (DM) basis). Each TMR was placed in a plastic drum silo, stored at 23°C in an air-conditioned room and sampled 0, 7, 14, 30, 90 and 210 days after preparation. In both grain sources, the fermentation products increased, while DM and starch storage losses increased and starch content greatly decreased during storage. The rapidly degradable fraction and effective ruminal degradability of DM, crude protein and starch increased during storage. These changes of dietary characteristics were large during 30 days of storage, but small after 90 days of storage. Replacing corn with BR led to increased fermentation products, starch loss and effective ruminal degradability of the ensiled TMR. These results indicate that the ensiling process of TMR changes the dietary characteristics and replacing corn with BR in TMR had a large impact on these dietary characteristics. © 2016 Japanese Society of Animal Science.

  18. Single gene retrieval from thermally degraded DNA

    Indian Academy of Sciences (India)

    Unknown

    DNA thermal degradation was shown to occur via a singlet oxygen pathway. A comparative study of the ther- mal degradation of cellular DNA and isolated DNA showed that cellular ..... definite level of energy (e.g. depurination active energy,.

  19. Process optimization for microcystin-LR degradation by Response Surface Methodology and mechanism analysis in gas-liquid hybrid discharge system.

    Science.gov (United States)

    Zhang, Yi; Wei, Hanyu; Xin, Qing; Wang, Mingang; Wang, Qi; Wang, Qiang; Cong, Yanqing

    2016-12-01

    A gas-liquid hybrid discharge system was applied to microcystin-LR (MC-LR) degradation. MC-LR degradation was completed after 1 min under a pulsed high voltage of 16 kV, gas-liquid interface gap of 10 mm and oxygen flow rate of 160 L/h. The Box-Behnken Design was proposed in Response Surface Methodology to evaluate the influence of pulsed high voltage, electrode distance and oxygen flow rate on MC-LR removal efficiency. Multiple regression analysis, focused on multivariable factors, was employed and a reduced cubic model was developed. The ANOVA analysis shows that the model is significant and the model prediction on MC-LR removal was also validated with experimental data. The optimum conditions for the process are obtained at pulsed voltage of 16 kV, gas-liquid interface gap of 10 mm and oxygen flow rate of 120 L/h with ta removal efficiency of MC-LR of 96.6%. The addition of catalysts (TiO 2 or Fe 2+ ) in the gas-liquid hybrid discharge system was found to enhance the removal of MC-LR. The intermediates of MC-LR degradation were analyzed by liquid chromatography/mass spectrometry. The degradation pathway proposed envisaged the oxidation of hydroxyl radicals and ozone, and attack of high-energy electrons on the unsaturated double bonds of Adda and Mdha, with MC-LR finally decomposing into small molecular products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Discovery of LPMO activity on hemicelluloses shows the importance of oxidative processes in plant cell wall degradation

    DEFF Research Database (Denmark)

    Agger, Jane W.; Isaksen, Trine; Várnai, Anikó

    2014-01-01

    of LPMOs, and considering the complexity and copolymeric nature of the plant cell wall, it has been speculated that some LPMOs may act on other substrates, in particular the hemicelluloses that tether to cellulose microfibrils. We demonstrate that an LPMO from Neurospora crassa, NcLPMO9C, indeed degrades...... walls. Products generated by NcLPMO9C were analyzed using high performance anion exchange chromatography and multidimensional mass spectrometry. We show that NcLPMO9C generates oxidized products from a variety of substrates and that its product profile differs from those of hydrolytic enzymes acting...... on the same substrates. The enzyme particularly acts on the glucose backbone of xyloglucan, accepting various substitutions (xylose, galactose) in almost all positions. Because the attachment of xyloglucan to cellulose hampers depolymerization of the latter, it is possible that the beneficial effect...

  1. On the experimental approaches for the assessment of the release of engineered nanomaterials from nanocomposites by physical degradation processes

    International Nuclear Information System (INIS)

    Blázquez, M; Unzueta, I; Egizabal, A

    2014-01-01

    The LIFE+ Project SIRENA, Simulation of the release of nanomaterials from consumer products for environmental exposure assessment, (LIFE11 ENV/ES/596) has set up a Technological Surveillance System (TSS) to trace technical references at worldwide level related to nanocomposites and the release from nanocomposites. So far a total of seventy three items of different nature (from peer reviewed articles to presentations and contributions to congresses) have been selected and classified as n anomaterials release simulation technologies . In present document, different approaches for the simulation of different life cycle stages through the physical degradation of polymer nanocomposites at laboratory scale are assessed. In absence of a reference methodology, the comparison of the different protocols used still remains a challenge

  2. On the experimental approaches for the assessment of the release of engineered nanomaterials from nanocomposites by physical degradation processes

    Science.gov (United States)

    Blázquez, M.; Egizabal, A.; Unzueta, I.

    2014-08-01

    The LIFE+ Project SIRENA, Simulation of the release of nanomaterials from consumer products for environmental exposure assessment, (LIFE11 ENV/ES/596) has set up a Technological Surveillance System (TSS) to trace technical references at worldwide level related to nanocomposites and the release from nanocomposites. So far a total of seventy three items of different nature (from peer reviewed articles to presentations and contributions to congresses) have been selected and classified as "nanomaterials release simulation technologies". In present document, different approaches for the simulation of different life cycle stages through the physical degradation of polymer nanocomposites at laboratory scale are assessed. In absence of a reference methodology, the comparison of the different protocols used still remains a challenge.

  3. Decontamination of PAH polluted soils by fungi. Subproject: PAH degradation balance and testing of the extended laboratory process. Final report

    International Nuclear Information System (INIS)

    Martens, R.; Zadrazil, F.; Wolter, M.; Bahadir, M.

    1997-01-01

    The aim of the research project was first to select a fungus with a high potential for mineralization of polycyclic aromatic hydrocarbons (PAH) and a good ability to colonize different soils. The application of this fungus for a degradation of PAH in soil had to be tested. In a screening of 57 white rot fungi the fungus Pleurotus sp. Florida fulfilled these requirements best. In pure culture it was able to metabolize and mineralize highly condensed 4-6 ring PAH to a great extent. For instance, up to 50% of 14 C-pyrene or 39% of 14 C-benzo(a)pyrene was mineralized to 14 CO 2 within 15 weeks. If different carriers for 14 C-pyrene were used the mineralization correlated with the bioavailability, which was characterized by the desorption of the compound from the carriers with water. The mineralization of 14 C-pyrene, 14 C-benz(a)anthracene; 14 C-benzo(a)-pyrene and 14 C-dibenz(a, h)anthracene in native soils showed that a colonization with Pl. sp Florida inhibited the degradation of the less recalcitrant 14 C-pyrene by the indigenous soil microflora. However, the mineralization of the carcinogenic, very recalcitrant and high condensed 14 C-PAH was considerably supported by the fungus. Therefore this capabilities of the fungus could not be proven in a joint medium-scale soil experiment (0.8 m 3 soil) which had been conducted within a parmership with scientists in Jena and an industriell firm. Because of safety aspects only the low condensed less recalcitrant PAH could be applied in this experiment. (orig./MG) [de

  4. DNA degradation in genetically modified rice with Cry1Ab by food processing methods: implications for the quantification of genetically modified organisms.

    Science.gov (United States)

    Xing, Fuguo; Zhang, Wei; Selvaraj, Jonathan Nimal; Liu, Yang

    2015-05-01

    Food processing methods contribute to DNA degradation, thereby affecting genetically modified organism detection and quantification. This study evaluated the effect of food processing methods on the relative transgenic content of genetically modified rice with Cry1Ab. In steamed rice and rice noodles, the levels of Cry1Ab were ⩾ 100% and <83%, respectively. Frying and baking in rice crackers contributed to a reduction in Pubi and Cry1Ab, while microwaving caused a decrease in Pubi and an increase in Cry1Ab. The processing methods of sweet rice wine had the most severe degradation effects on Pubi and Cry1Ab. In steamed rice and rice noodles, Cry1Ab was the most stable, followed by SPS and Pubi. However, in rice crackers and sweet rice wine, SPS was the most stable, followed by Cry1Ab and Pubi. Therefore, Cry1Ab is a better representative of transgenic components than is Pubi because the levels of Cry1Ab were less affected compared to Pubi. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Microbial consortia involved in the anaerobic degradation of hydrocarbons.

    Science.gov (United States)

    Zwolinski; Harris, R F; Hickey, W J

    2000-01-01

    In this review, we examine the energetics of well-characterized biodegradation pathways and explore the possibilities for these to support growth of multiple organisms interacting in consortia. The relevant phenotypic and/or phylogenetic characteristics of isolates and consortia mediating hydrocarbon degradation coupled with different terminal electron-accepting processes (TEAP) are also reviewed. While the information on metabolic pathways has been gained from the analysis of individual isolates, the energetic framework presented here demonstrates that microbial consortia could be readily postulated for hydrocarbon degradation coupled to any TEAP. Several specialized reactions occur within these pathways, and the organisms mediating these are likely to play a key role in defining the hydrocarbon degradation characteristics of the community under a given TEAP. Comparing these processes within and between TEAPs reveals biological unity in that divergent phylotypes display similar degradation mechanisms and biological diversity in that hydrocarbon-degraders closely related as phylotypes differ in the type and variety of hydrocarbon degradation pathways they possess. Analysis of microcosms and of field samples suggests that we have only begun to reveal the diversity of organisms mediating anaerobic hydrocarbon degradation. Advancements in the understanding of how hydrocarbon-degrading communities function will be significantly affected by the extent to which organisms mediating specialized reactions can be identified, and tools developed to allow their study in situ.

  6. Antifoam Degradation Products in Off Gas and Condensate of Sludge Batch 9 Simulant Nitric-Formic Flowsheet Testing for the Defense Waste Processing Facility

    Energy Technology Data Exchange (ETDEWEB)

    Smith, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-04-14

    Ten chemical processing cell (CPC) experiments were performed using simulant to evaluate Sludge Batch 9 for sludge-only and coupled processing using the nitric-formic flowsheet in the Defense Waste Processing Facility (DWPF). Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on eight of the ten. The other two were SRAT cycles only. Samples of the condensate, sludge, and off gas were taken to monitor the chemistry of the CPC experiments. The Savannah River National Laboratory (SRNL) has previously shown antifoam decomposes to form flammable organic products, (hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and propanal), that are present in the vapor phase and condensate of the CPC vessels. To minimize antifoam degradation product formation, a new antifoam addition strategy was implemented at SRNL and DWPF to add antifoam undiluted.

  7. Polycarbonate radiolytic degradation and stabilization

    International Nuclear Information System (INIS)

    Araujo, E.S. de

    1994-01-01

    Polycarbonate Durolon, useful for medical supplies fabrication, is submitted to gamma radiation for sterilization purposes. Scissions in main chain occur, in carbonyl groups, producing molecular degradations and yellowness. The radiolytic stabilization is obtained through additive to the polymer. In this work some degradation and stabilization aspects are presented. (L.C.J.A.). 7 refs, 7 figs, 2 tabs

  8. Plant species responses to oil degradation and toxicity reduction in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-01-05

    Jan 5, 2009 ... contaminated soil and sediment is an emerging techno- logy that promises effective and inexpensive clean up of certain hazardous wastes (Simeon 1993; Nwoko, 1995). Some of these processes occurs within the plants and involves the degradation or breakdown of organic and inorganic contaminants ...

  9. Intermittent degradation and schizotypy

    Directory of Open Access Journals (Sweden)

    Matthew W. Roché

    2015-06-01

    Full Text Available Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-report questionnaires assessing schizotypy and psychological state variables (e.g., anxiety, depression, and their reaction times were recorded as they did so. Intermittent degradation was defined as the number of times a subject’s reaction time for questionnaire items met or exceeded three standard deviations from his or her mean reaction time after controlling for each item’s information processing load. Intermittent degradation scores were correlated with questionnaire scores. Our results indicate that intermittent degradation is associated with total scores on measures of positive and disorganized schizotypy, but unrelated to total scores on measures of negative schizotypy and psychological state variables. Intermittent degradation is interpreted as potentially derivative of schizotypy and a candidate endophenotypic marker worthy of continued research.

  10. Impact of processing conditions on the kinetic of vitamin C degradation and 2-furoylmethyl amino acid formation in dried strawberries.

    Science.gov (United States)

    Gamboa-Santos, Juliana; Megías-Pérez, Roberto; Soria, A Cristina; Olano, Agustín; Montilla, Antonia; Villamiel, Mar

    2014-06-15

    In this paper, a study on the usefulness of the determination of vitamin C together with indicators of the initial steps of Maillard reaction (2-furoylmethyl amino acids, 2-FM-AA) during the convective drying of strawberries has been carried out for the first time, paying special attention to the kinetics of degradation and formation, respectively, of both parameters. Formation of 2-FM-AA of Lys, Arg and GABA and vitamin C loss increased with time and temperature following, respectively, a zero and first-order kinetics. As supported by its lower activation energy, 2-FM-GABA (55.9 kJ/mol) and 2-FM-Lys+2-FM-Arg (58.2 kJ/mol) were shown to be slightly more sensitive indicators than vitamin C (82.1 kJ/mol). The obtained results, together with a complementary study on the rehydration ability and sensorial attributes of samples, pointed out the suitability of the convective drying system to obtain dried strawberries of high nutritive quality and bioactivity and good consumer acceptance. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Electrocatalytic properties of N-doped graphite felt in electro-Fenton process and degradation mechanism of levofloxacin.

    Science.gov (United States)

    Liu, Xiaocheng; Yang, Danxing; Zhou, Yaoyu; Zhang, Jiachao; Luo, Lin; Meng, Sijun; Chen, Song; Tan, Mengjiao; Li, Zhicheng; Tang, Lin

    2017-09-01

    The degradation of antibiotic levofloxacin was investigated by dimensionally stable anode as well as modified cathode using low-cost chemical reagents of hydrazine hydrate and ethanol for electro-Fenton in an undivided cell at pH 3.0 under room temperature. Comparison of unmodified and modified cathode was performed. The apparent rate constant of levofloxacin decay was found to be 0.2883 min -1 for graphite felt-10 with the best performance at 200 mA, which is lower than graphite felt at 400 mA. The optimum modified cathode showed a significant improvement of complete mineralization of levofloxacin, reaching a 92% TOC removal at 200 mA for 480 min higher than unmodified one at twice the current. Surface physicochemical properties and morphology were investigated by scanning electron microscope, contact angle and X-ray photoelectron spectroscopy. The electrochemical characterization of hydrogen evolution reaction was adopted to clarify a possible pathway for the higher mineralization of levofloxacin, indicating a potential pilot-scale study to the pollution with the similar structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Synergistic operation of photocatalytic degradation and Fenton process by magnetic Fe3O4 loaded TiO2

    Science.gov (United States)

    Sun, Qiong; Hong, Yong; Liu, Qiuhong; Dong, Lifeng

    2018-02-01

    The magnetic Fe3O4 loaded anatase TiO2 photocatalysts with different mass ratios were successfully synthesized by a one-step convenient calcining method. The morphology and structure analysis revealed that Fe3O4 was formed in TiO2 with very fine-grained particles. After a small amount of Fe3O4 loaded onto TiO2, the photocatalytic property enhanced obviously for the degradation of organic dye. Furthermore, the photo-Fenton-like catalysis of the iron-containing samples could also be induced after the addition of hydrogen peroxide. The apparent kinetic constant of the reaction that catalyzed by Fe-TiO2 was about 5.3 and 8.3 times of that catalyzed by TiO2 or Fe3O4 only, respectively, proving an effective synergistic contribution of the photocatalysis and Fenton reaction in the composite. Compared with Fe3O4 or free Fe3+ ions, only 13% of iron in TiO2 dissolved into acidic solution (25% for Fe3O4 and 100% for Fe3+) after the reaction, which confirmed the iron had been well immobilized onto TiO2. In addition, the extremely stable photocatalytic activity in cycling experiments proved the immobilized iron had been tightly attached onto TiO2, indicating the great potential of the catalyst for practical applications.

  13. Comparative performance of anodic oxidation and electrocoagulation as clean processes for electrocatalytic degradation of diazo dye Acid Brown 14 in aqueous medium.

    Science.gov (United States)

    Bassyouni, D G; Hamad, H A; El-Ashtoukhy, E-S Z; Amin, N K; El-Latif, M M Abd

    2017-08-05

    In this study, a laboratory scale for the treatment of a recalcitrant and toxic synthetic wastewater containing diazo dye, acid brown 14 (AB-14) has been comparatively performed by two electro-catalytic treatment processes, namely anodic oxidation (AO) and electrocoagulation (EC) using a new batch electrochemical cell. Additionally, the influence of several operating parameters such as; current density (j), initial dye concentration (C o ), NaCl concentration (C N ), and pH on the color removal efficiency and chemical oxygen demand (COD) are evaluated. The powerful capability of the AO and EC of AB-14 which related to the mechanistic reaction pathway is shown. The poor degradation is ascribed to higher C o and pH, while the enhancement of j and C N is responsible for better degradation of AB-14 dye. The results indicate that the EC is more effective than AO under the same operational condition. A kinetic model is developed for evaluation of the pseudo-first-order-rate constant (k app ) as a function of various operational parameters. The results emphasize the high efficiency of AO and EC and the clean processes which are hopeful alternative for the treatment of the large volume wastewater of the textile industry. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Lignocellulose Biomass: Constitutive Polymers. Biological Processes of Lignin Degradation; Biomasa lignocelulosica, polimeros constitutivos. Procesos biologicos de degradacion de la lignina

    Energy Technology Data Exchange (ETDEWEB)

    Martin, C; Manzanares, P

    1994-07-01

    The structure of the lignocellulosic materials and the chemical composition of their main constitutive polymers, cellulose, hemicelluloses and lignin are described. The most promising transformation processes according to the type of biomass considered: hardwood, softwood an herbaceous and the perspectives of biotechnological processes for bio pulping, bio bleaching and effluents decolorisation in the paper pulp industry are also discussed. (Author) 7 refs.

  15. Oxidation of microcystin-LR by the Fenton process : Kinetics, degradation intermediates, water quality and toxicity assessment

    NARCIS (Netherlands)

    Park, Jeong-Ann; Yang, Boram; Park, Chanhyuk; Choi, Jae-Woo; van Genuchten, Case M.|info:eu-repo/dai/nl/413489647; Lee, Sang-Hyup

    2017-01-01

    The Fenton process was assessed as a cost-effective technology for the removal of Microcystin-LR (MC-LR) among UV, UV/H2O2, and Fenton process according to efficiency and electrical energy per order (EE/O). The determined practical concentrations of the Fenton reagents were 5 mg/L Fe(II) and 5 mg/L

  16. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  17. Aquatic degradation of textile dyes using ionizing and non ionizing radiation

    International Nuclear Information System (INIS)

    Sadek, S.A.; Abdel-Hamid, A.S.; Ebraheem, S.

    2002-01-01

    Complete text of publication follows. In this study the possibility of the use of γ-rays and sunlight for the degradation of fast violet 2rl (fv) and astrazone red 6b (ar) were investigated. These dyes are released to the wastewater streams originating from the industrial textile processing. The degree of degradation in dye concentration was calculated and was found to be completed at about 3.0 kGy for fast violet and at about 1.5 for astrazone in the case of using sunlight, the degradation was completed in two hours by using titanium dioxide as heterogeneous catalyst in the medium, while without any additives the degradation occurred in 30 days for both dyes. The kinetics of degradation process was found to follow first order reaction. The effect of O 2 , N 2 , H 2 O 2 on the rate of degradation was also studied

  18. Degradation of paracetamol by advance oxidation processes using modified reticulated vitreous carbon electrodes with TiO(2) and CuO/TiO(2)/Al(2)O(3).

    Science.gov (United States)

    Arredondo Valdez, H C; García Jiménez, G; Gutiérrez Granados, S; Ponce de León, C

    2012-11-01

    The degradation of paracetamol in aqueous solutions in the presence of hydrogen peroxide was carried out by photochemistry, electrolysis and photoelectrolysis using modified 100 pores per inch reticulated vitreous carbon electrodes. The electrodes were coated with catalysts such as TiO(2) and CuO/TiO(2)/Al(2)O(3) by electrophoresis followed by heat treatment. The results of the electrolysis with bare reticulated vitreous carbon electrodes show that 90% paracetamol degradation occurs in 4 h at 1.3 V vs. SCE, forming intermediates such as benzoquinone and carboxylic acids followed by their complete mineralisation. When the electrolysis was carried out with the modified electrodes such as TiO(2)/RVC, 90% degradation was achieved in 2 h while with CuO/TiO(2)/Al(2)O(3)/RVC, 98% degradation took only 1 h. The degradation was also carried out in the presence of UV reaching 95% degradation with TiO(2)/RVC/UV and 99% with CuO/TiO(2)/Al(2)O(3)/RVC/UV in 1 h. The reactions were followed by spectroscopy UV-Vis, HPLC and total organic carbon analysis. These studies show that the degradation of paracetamol follows a pseudo-first order reaction kinetics. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Electrochemically Obtained TiO2/CuxOy Nanotube Arrays Presenting a Photocatalytic Response in Processes of Pollutants Degradation and Bacteria Inactivation in Aqueous Phase

    Directory of Open Access Journals (Sweden)

    Magda Kozak

    2018-06-01

    Full Text Available TiO2/CuxOy nanotube (NT arrays were synthesized using the anodization method in the presence of ethylene glycol and different parameters applied. The presence, morphology, and chemical character of the obtained structures was characterized using a variety of methods—SEM (scanning electron microscopy, XPS (X-ray photoelectron spectroscopy, XRD (X-ray crystallography, PL (photoluminescence, and EDX (energy-dispersive X-ray spectroscopy. A p-n mixed oxide heterojunction of Ti-Cu was created with a proved response to the visible light range and the stable form that were in contact with Ti. TiO2/CuxOy NTs presented the appearance of both Cu2O (mainly and CuO components influencing the dimensions of the NTs (1.1–1.3 µm. Additionally, changes in voltage have been proven to affect the NTs’ length, which reached a value of 3.5 µm for Ti90Cu10_50V. Degradation of phenol in the aqueous phase was observed in 16% of Ti85Cu15_30V after 1 h of visible light irradiation (λ > 420 nm. Scavenger tests for phenol degradation process in presence of NT samples exposed the responsibility of superoxide radicals for degradation of organic compounds in Vis light region. Inactivation of bacteria strains Escherichia coli (E. coli, Bacillus subtilis (B. subtilis, and Clostridium sp. in presence of obtained TiO2/CuxOy NT photocatalysts, and Vis light has been studied showing a great improvement in inactivation efficiency with a response rate of 97% inactivation for E. coli and 98% for Clostridium sp. in 60 min. Evidently, TEM (transmission electron microscopy images confirmed the bacteria cells’ damage.

  20. Preliminary degradation process study of infectious biological waste in a 5 k W thermal plasma equipment.; Estudio Preliminar de Proceso de degradacion de residuos biologico-infecciosos en un equipo de plasma termico de 5 kW

    Energy Technology Data Exchange (ETDEWEB)

    Xochihua S M, M C

    1998-12-31

    This work is a preliminary study of infectious biological waste degradation process by thermal plasma and was made in Thermal Plasma Applications Laboratory of Environmental Studies Department of the National Institute of Nuclear Research (ININ). Infectious biological waste degradation process is realized by using samples such polyethylene, cotton, glass, etc., but the present study scope is to analyze polyethylene degradation process with mass and energy balances involved. Degradation method is realized as follow: a polyethylene sample is put in an appropriated crucible localized inside a pyrolysis reactor chamber, the plasma jet is projected to the sample, by the pyrolysis phenomena the sample is degraded into its constitutive particles: carbon and hydrogen. Air was utilized as a recombination gas in order to obtain the higher percent of CO{sub 2} if amount of O{sub 2} is greater in the recombination gas, the CO generation is reduced. The effluent gases of exhaust pyrolysis reactor through are passed through a heat exchanger to get cooled gases, the temperature water used is 15 Centigrade degrees. Finally the gases was tried into absorption tower with water as an absorbent fluid. Thermal plasma degradation process is a very promising technology, but is necessary to develop engineering process area to avail all advantages of thermal plasma. (Author).

  1. Degradation of fluorotelomer alcohols

    DEFF Research Database (Denmark)

    Ellis, David A; Martin, Jonathan W; De Silva, Amila O

    2004-01-01

    Human and animal tissues collected in urban and remote global locations contain persistent and bioaccumulative perfluorinated carboxylic acids (PFCAs). The source of PFCAs was previously unknown. Here we present smog chamber studies that indicate fluorotelomer alcohols (FTOHs) can degrade...... in the atmosphere to yield a homologous series of PFCAs. Atmospheric degradation of FTOHs is likely to contribute to the widespread dissemination of PFCAs. After their bioaccumulation potential is accounted for, the pattern of PFCAs yielded from FTOHs could account for the distinct contamination profile of PFCAs....... The significance of the gas-phase peroxy radical cross reactions that produce PFCAs has not been recognized previously. Such reactions are expected to occur during the atmospheric degradation of all polyfluorinated materials, necessitating a reexamination of the environmental fate and impact of this important...

  2. Integrated electrocoagulation-electrooxidation process for the treatment of soluble coffee effluent: Optimization of COD degradation and operation time analysis.

    Science.gov (United States)

    Ibarra-Taquez, Harold N; GilPavas, Edison; Blatchley, Ernest R; Gómez-García, Miguel-Ángel; Dobrosz-Gómez, Izabela

    2017-09-15

    Soluble coffee production generates wastewater containing complex mixtures of organic macromolecules. In this work, a sequential Electrocoagulation-Electrooxidation (EC-EO) process, using aluminum and graphite electrodes, was proposed as an alternative way for the treatment of soluble coffee effluent. Process operational parameters were optimized, achieving total decolorization, as well as 74% and 63.5% of COD and TOC removal, respectively. The integrated EC-EO process yielded a highly oxidized (AOS = 1.629) and biocompatible (BOD 5 /COD ≈ 0.6) effluent. The Molecular Weight Distribution (MWD) analysis showed that during the EC-EO process, EC effectively decomposed contaminants with molecular weight in the range of 10-30 kDa. In contrast, EO was quite efficient in mineralization of contaminants with molecular weight higher than 30 kDa. A kinetic analysis allowed determination of the time required to meet Colombian permissible discharge limits. Finally, a comprehensive operational cost analysis was performed. The integrated EC-EO process was demonstrated as an efficient alternative for the treatment of industrial effluents resulting from soluble coffee production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Degradability of dry matter and crude protein of dry grains and wet grain silages from different processing corn hybrids (Zea mays

    Directory of Open Access Journals (Sweden)

    Wagner dos Reis

    2013-03-01

    Full Text Available The objective of this work was to evaluate the effect of processing two corn hybrids conserved, dry and humid grains, the dry matter (DM and crude protein (CP degradability in situ. The particle size was determined and difference was verified in MGD (Medium Geometric Diameter of processed ingredients. Three sheep were used with rumen canulated, in a completely randomized design, using a factorial outline 2 x 2 x 3, being two corn hybrid, two conservation methods and three processing forms (whole, coarsely and finely ground, with five times of incubation (3, 6, 12, 24 and 48 hours. The fraction A in SDC (silage of dent corn of DM was superior to GDC (grain of dent corn in all of the particles size. The ensiling process increased the DM solubility, reducing the fraction B in comparison to dry grain. The values regarding the fractions DP and DE the 5% per hour of the protein, were larger for SDC and GDC, it presents a decreasing when the incubation time advances. The fermentation rate was superior for SDC and GDC. The ensiling process has positive effect in the decreasing of DM and CP in comparison to GDC.

  4. Cold Incineration of Chlorophenols in Aqueous Solution by Advanced Electrochemical Process Electro-Fenton. Effect of Number and Position of Chlorine Atoms on the Degradation Kinetics

    Science.gov (United States)

    Oturan, Nihal; Panizza, Marco; Oturan, Mehmet A.

    2009-09-01

    This study reports the kinetics of the degradation of several chlorophenols (CPs), such as monochlorophenols (2-chlorophenol and 4-chlorophenol), dichlorophenols (2,4-dichlorophenol and 2,6- dichlorophenol), trichlorophenols (2,3,5- trichlorophenol and 2,4,5-trichlorophenol), 2,3,5,6-tetrachlorophenol, and pentachlorophenol, by the electro-Fenton process using a carbon felt cathode and a Pt anode. The effect of number and the position of the chlorine atoms in the aromatic ring on the oxidative degradation rate was evaluated and discussed. The oxidation reaction of all the CPs with hydroxyl radicals evidenced a pseudo-first-order kinetics and the rate constant decreased with increasing the number of chlorine atoms. The absolute rate constant of second-order reaction kinetics between CPs and •OH was determined by the competition kinetics method in the range of (3.56-7.75) × 109 M-1 s-1 and follows the same sequence of the apparent rate constants. The mineralization of several CPs and of a mixture of all CPs under study was monitored by the total organic carbon (TOC) removal and the chlorine release during mineralization was followed by ion chromatography. Our results demonstrated that more chlorinated phenols are more difficult to mineralize; however for all the tested CPs, almost quantitative release of chloride ions was obtained after 6 h of treatment.

  5. Epstein-Barr virus nuclear antigen 1 (EBNA1) induced cytotoxicity in epithelial cells is associated with EBNA1 degradation and processing

    International Nuclear Information System (INIS)

    Jones, Richard J.; Smith, Laura J.; Dawson, Christopher W.; Haigh, Tracy; Blake, Neil W.; Young, Lawrence S.

    2003-01-01

    Epstein-Barr virus nuclear antigen 1 (EBNA1) has a central role in the maintenance and segregation of the Epstein-Barr virus (EBV) episome and by virtue of a glycine-alanine repeat domain is prevented from being endogenously processed for recognition by HLA class I restricted cytotoxic T lymphocytes (CTLs). We found that EBNA1 expression resulted in growth inhibition and a G2/M arrest in human squamous epithelial cell lines (SCC12F, SVK) but not epithelial cell lines of glandular origin (Hela, Ad/AH). The cytotoxicity of EBNA1 was associated with EBNA1 degradation and both these effects were blocked in SCC12F cells expressing either the anti-apoptotic bcl-2 protein or the EBV homolog of bcl-2, BHRF1. The endogenous degradation of EBNA1 in SVK epithelial cells was associated with specific CTL recognition, an effect not evident in EBNA1-expressing Hela cells. Consistent with the inability of SVK cells to tolerate EBNA1 expression, studies with a recombinant EBV demonstrated that SVK cells are unable to maintain stable virus infection, whereas Hela cells are able to efficiently establish latent EBV infection. These data have important implications for both the cellular requirements necessary to sustain a stable EBV infection and for the possible role of CTL responses in controlling EBV infection of epithelial cells

  6. Application of Radiation Degraded Chitosan as Plant Growth Promoter. A Pilot Scale Production and Field Trial Study of Radiation Processed Chitosan as Plant Growth Promoter for Rice Crops

    International Nuclear Information System (INIS)

    Dahlan, Khairul Zaman Hj Mohd; Hashim, Kamaruddin; Bahari, Kamarudin

    2010-01-01

    The application of radiation processed chitosan as plant growth promoter has been carried out in the 24 hectares of rice crops. For the field trial, a pilot scale production of oligochitosan was established using gamma irradiation for partial degradation of chitosan powder of DDA 90% and followed by gamma irradiation of aqueous solution of 3% irradiated chitosan powder in 2% lactic acids (3CL2). Radiation dose of 50 kGy was selected for initial degradation of chitosan powder and followed by 12 kGy irradiation of 3CL2. A viscosity average molecular weight of ~10,000 of oligochitosan was obtained and subsequently used in the field trial of MR219 type of rice seeds on 24 hectares of rice plots. The seedlings were carried out after the rice seeds were soaked 24hrs in water and 30 minutes in 200ppm oligochitosan. The rice plots that were sprayed with oligochitosan were found to have higher resistant towards blast diseases. Oligochitosan of 40ppm was found to be effective as fungicides and resulted in the increase of yield of rice seeds of about 5%. (author)

  7. Antifoam degradation testing

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Zamecnik, J. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Newell, D. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Williams, M. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL)

    2015-08-20

    This report describes the results of testing to quantify the degradation products resulting from the dilution and storage of Antifoam 747. Antifoam degradation is of concern to the Defense Waste Processing Facility (DWPF) due to flammable decomposition products in the vapor phase of the Chemical Process Cell vessels, as well as the collection of flammable and organic species in the offgas condensate. The discovery that hexamethyldisiloxane is formed from the antifoam decomposition was the basis for a Potential Inadequacy in the Safety Analysis declaration by the DWPF.

  8. The mechanism of degradation of bisphenol A using the magnetically separable CuFe_2O_4/peroxymonosulfate heterogeneous oxidation process

    International Nuclear Information System (INIS)

    Xu, Yin; Ai, Jia; Zhang, Hui

    2016-01-01

    Highlights: • Copper ferrite (CuFe_2O_4) was fabricated and utilized in heterogeneous PMS process. • The influence of reaction parameters for the mineralization of BPA were evaluated. • Possible reaction mechanism and the stability of CuFe_2O_4 were investigated. • Surface bound radicals (mainly ·OH) may be responsible for the BPA degradation. - Abstract: The removal of bisphenol A (BPA) in aqueous solution by an oxidation process involving peroxymonosulfate (PMS) activated by CuFe_2O_4 magnetic nanoparticles (MNPs) is reported herein. The effects of PMS concentration, CuFe_2O_4 dosage, initial pH, initial BPA concentration, catalyst addition mode, and anions (Cl"−, F"−, ClO_4"− and H_2PO_4"−) on BPA degradation were investigated. Results indicate that nearly complete removal of BPA (50 mg/L) within 60 min and 84.0% TOC removal in 120 min could be achieved at neutral pH by using 0.6 g/L CuFe_2O_4 MNPs and 0.3 g/L PMS. The generation of reactive radicals (mainly hydroxyl radicals) was confirmed using electron paramagnetic resonance (EPR). Possible mechanisms on the radical generation from CuFe_2O_4/PMS system are proposed based on the results of radical identification tests and XPS analysis. The lack of inhibition of the reaction by free radical scavengers such as methanol and tert-butyl alcohol suggests that these species may not be generated in the bulk solution, and methylene blue probe experiments confirm that this process does not involve free radical generation. Surface-bound, rather than free radicals generated by a surface catalyzed-redox cycle involving both Fe(III) and Cu(II), are postulated to be responsible for the mineralization of bisphenol A.

  9. Degradation of Pentachlorophenol in Aqueous Solution by the UV/ZrO 2 /H 2 O 2 Photocatalytic Process

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Samarghandi

    2015-12-01

    Full Text Available Pentachlorophenol (PCP, which is one of the resistant phenolic compounds, has been classified in the category of EPA’s priority pollutants due to its high toxicity and carcinogenic potential. Therefore, its removal from water and wastewater is very important. Various methods have been studied for removing the compound, among which advanced oxidation processes (AOPs have attracted much attention because of ease of application and high efficiency. Thus the aim of this study was to investigate the efficiency of the UV/ZrO2/H2O2 process, as an AOP, for PCP removal from aquatic environments. The effects of several parameters such as ultraviolet (UV exposure time, initial PCP concentration, pH, concentration of zirconium dioxide (ZrO2 nanoparticles, and H2O2 concentration were studied. Kinetics of the reaction was also detected. The concentration of the stated materials in the samples was determined using a spectrophotometer at 500 nm. The results showed that the highest efficiency (approximately 100% was reached at optimized conditions of pH 6, contact time of 30 minutes, initial PCP concentration of 20 mg/L, the nanoparticles concentration of 0.1 g/L and H2O2 concentration of 14.7 mM/L. Also, the process followed the first order kinetics reaction. The obtained results illustrated that the UV/ZrO2/H2O2 process has a high ability in removing PCP.

  10. Degradation and biodegradability improvement of the olive mill wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes.

    Science.gov (United States)

    Esfandyari, Yahya; Mahdavi, Yousef; Seyedsalehi, Mahdi; Hoseini, Mohammad; Safari, Gholam Hossein; Ghozikali, Mohammad Ghanbari; Kamani, Hossein; Jaafari, Jalil

    2015-04-01

    Olive mill wastewater is considered as one of the most polluting effluents of the food industry and constitutes a source of important environmental problems. In this study, the removal of pollutants (chemical oxygen demand (COD), biochemical oxygen demand (BOD5), polyphenols, turbidity, color, total suspended solids (TSS), and oil and grease) from olive oil mill processing wastewater by peroxi-electrocoagulation/electrooxidation-electroflotation process with bipolar aluminum electrodes was evaluated using a pilot continuous reactor. In the electrochemical unit, aluminum (Al), stainless steel, and RuO2/Ti plates were used. The effects of pH, hydrogen peroxide doses, current density, NaCl concentrations, and reaction times were studied. Under optimal conditions of pH 4, current density of 40 mA/m(2), 1000 mg/L H2O2, 1 g/L NaCl, and 30-min reaction time, the peroxi-electrochemical method yielded very effective removal of organic pollution from the olive mill wastewater diluted four times. The treatment process reduced COD by 96%, BOD5 by 93.6%, total, polyphenols by 94.4%, color by 91.4%, turbidity by 88.7, suspended solids by 97% and oil and grease by 97.1%. The biodegradability index (BOD5/COD) increased from 0.29 to 0.46. Therefore, the peroxi-electrocoagulation/electrooxidation-electroflotation process is considered as an effective and feasible process for pre-treating olive mill wastewater, making possible a post-treatment of the effluent in a biological system.

  11. SPR sensors for monitoring the degradation processes of Eu(dbm)3(phen) and Alq3 thin films under atmospheric and UVA exposure

    Science.gov (United States)

    Del Rosso, T.; Zaman, Q.; Cremona, M.; Pandoli, O.; Barreto, A. R. J.

    2018-06-01

    The degradation processes of tris(8-hydroxyquinoline) (Alq3) and tris(dibenzoylmethane) mono(1,10-phenanthroline)europium(III) (Eu(dbm)3(phen)) thin films are investigated by the use of AFM, photoluminescence and SPR spectroscopy. The plasmonic sensors are operated both in air and nitrogen environments, where they are irradiated with controlled doses of UVA radiation. AFM results don't reveal the formation of heterogeneous phases and crystallization under air exposure. The organic thin films change their refractive index under both types of exposure and act as a protective layer against oxidation for the SiO2/MPTS/metal interface of the plasmonic sensors. SPR measurements reveal a strict correlation between the refractive index increase and quenching of the photoluminescence of the organic thin films. The results are promising for the development of compact plasmonic UVA dosimeters in the surface plasmon coupled emission configuration (SPCE) with lanthanide β-diketonate complex materials (patent pending).

  12. In situ study of the growth and degradation processes in tetragonal lysozyme crystals on a silicon substrate by high-resolution X-ray diffractometry

    Science.gov (United States)

    Kovalchuk, M. V.; Prosekov, P. A.; Marchenkova, M. A.; Blagov, A. E.; D'yakova, Yu. A.; Tereshchenko, E. Yu.; Pisarevskii, Yu. V.; Kondratev, O. A.

    2014-09-01

    The results of an in situ study of the growth of tetragonal lysozyme crystals by high-resolution X-ray diffractometry are considered. The crystals are grown by the sitting-drop method on crystalline silicon substrates of different types: both on smooth substrates and substrates with artificial surface-relief structures using graphoepitaxy. The crystals are grown in a special hermetically closed crystallization cell, which enables one to obtain images with an optical microscope and perform in situ X-ray diffraction studies in the course of crystal growth. Measurements for lysozyme crystals were carried out in different stages of the crystallization process, including crystal nucleation and growth, developed crystals, the degradation of the crystal structure, and complete destruction.

  13. Study of degradation processes of metals used in some artworks from the cultural heritage of Andalusia, Spain

    Energy Technology Data Exchange (ETDEWEB)

    Duran, A.; Herrera, L. K.; Jimenez de Haro, M. C.; Pere-Rodriguez, J. L.; Justo, A.

    2009-07-01

    The study of the alteration processes of metals, such as lead, bronze, iron and tin-mercury alloys, used in some of the most important chosen artefacts of Andalusian Cultural Heritage is the main objective of this paper. Hydrocerussite and cerussete were detected in lead seals stored in a hole of cardboard. Bronze is altered to atacamite by environmental contamination, which is also responsible for the formation of rust from iron. Corrosion of the tin-mercury surface of amalgam mirrors produces tin monoxide and tin dioxide and releases liquid mercury from the solid phase. (Author) 38 refs.

  14. Application of advanced oxidation process by electron beam irradiation in the organic compounds degradation present in industrial effluents

    International Nuclear Information System (INIS)

    Duarte, Celina Lopes

    1999-01-01

    The inefficacy of conventional methods to destroy toxic organic compounds present in industrial effluent has taken the search for new technologies of treatment. he water irradiation is the most efficient process to generate radicals that mineralise these compounds. A study to evaluate the Advanced Oxidation Process by electron beam irradiation to treat industrial effluent with high toxic organic compounds concentration was carried out. Experiments were conducted using a Radiation Dynamics Electron Beam Accelerator with 1,5 MeV energy and 37 power. The effluent samples from a big industrial complex were irradiated using the IPEN's Liquid Effluent Irradiation Pilot Plant and the effluent samples from five steps of a Governmental Wastewater Treatment Plant from SABESP - ETE Suzano (industrial Receiver Unit, Coarse Bar Screens, Medium Bar Screens, Primary Sedimentation and Final Effluent), were irradiated in a batch system. The electron beam irradiation showed be efficient on destroying the organic compounds delivered in these effluents mainly chloroform, dichloroethane, methyl isobutyl ketone, benzene, toluene, xylene, phenol and in the decoloring of dyes present in some samples. To remove 90% of the most organic compounds was necessary a 20 kGy dose for industry's ETE, 20 kGy for IRU, CBS and MBS and 10 kGy to 20 kGy for PS and FE. (author)

  15. The distribution of naturally occurring radionuclides from ores processing to the environment - a case study of milling and treatment of ores for gold in Golden Star Resources of Bogoso Prestea Limited

    International Nuclear Information System (INIS)

    Gbadago, J.K.

    2010-01-01

    This research work was geared towards studying the distribution of naturally occurring radionuclides from the processing stages of oxide and sulphide ores for gold to the critical environment of the Golden Star Resources of Bogoso Prestea Limited in the Western region of Ghana. The study was carried out by measuring the natural radionuclide contents of raw feed ore and pulp samples from physical and chemical processing stages of oxide and sulphide ore treatment plants; tailings; de-silted sediments of a run-off from the tailings dam vicinity through a critical community and; soils and drinking water from the critical community. Also, as part of a comprehensive approach, the geochemical compositions were measured to determine any possible influence on the radionuclide distributions. Amongst the radionuclide decay chains, 238 U-series were the dominant throughout all the measurements. However, the concentrations are lower than the world permissible limits. The indicative doses associated with the activity concentration distributions in the processed feed ores at various processing stages ranged from 2 to 70 μSv/y in the oxide plant and from 2 to 108 μSv/y for the sulphide plant. If effective dose of ≤ 10 μSv/y recommended by IAEA for exemption from regulatory control is applied, the processing of ores in the plants must be regulated. However, the estimated annual effective dose received by the workers from any of these stages of operation did not exceed the range of 1-2 mSv recommended by the ICRP-75 (10 μSv/y ≤ Effective dose ≤ 1-2 mSv/y) for the exemption of a practice. This range is far lower than the annual occupational dose limit of 20 mSv/y recommended by IAEA for artificial radioactive sources. Imposing the IAEA recommendation of effective dose of ? 10 μSv/y for exemption from regulatory control of practices could result in many mining and other NORMs industries being regulated without any net benefit in terms of risk reduction. Conversely, Sn, As

  16. Pressurized Hot Water Extraction of anthocyanins from red onion: A study on extraction and degradation rates

    Energy Technology Data Exchange (ETDEWEB)

    Petersson, Erik V.; Liu Jiayin; Sjoeberg, Per J.R.; Danielsson, Rolf [Uppsala University, Department of Physical and Analytical Chemistry, P.O. Box 599, SE-751 24, Uppsala (Sweden); Turner, Charlotta, E-mail: Charlotta.Turner@kemi.uu.se [Uppsala University, Department of Physical and Analytical Chemistry, P.O. Box 599, SE-751 24, Uppsala (Sweden)

    2010-03-17

    Pressurized Hot Water Extraction (PHWE) is a quick, efficient and environmentally friendly technique for extractions. However, when using PHWE to extract thermally unstable analytes, extraction and degradation effects occur at the same time, and thereby compete. At first, the extraction effect dominates, but degradation effects soon take over. In this paper, extraction and degradation rates of anthocyanins from red onion were studied with experiments in a static batch reactor at 110 deg. C. A total extraction curve was calculated with data from the actual extraction and degradation curves, showing that more anthocyanins, 21-36% depending on the species, could be extracted if no degradation occurred, but then longer extraction times would be required than those needed to reach the peak level in the apparent extraction curves. The results give information about the different kinetic processes competing during an extraction procedure.

  17. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    D. Kicker

    2004-01-01

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal stress. (3) The DRKBA

  18. Drift Degradation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    D. Kicker

    2004-09-16

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal

  19. Application of quality by design concept to develop a dual gradient elution stability-indicating method for cloxacillin forced degradation studies using combined mixture-process variable models.

    Science.gov (United States)

    Zhang, Xia; Hu, Changqin

    2017-09-08

    Penicillins are typical of complex ionic samples which likely contain large number of degradation-related impurities (DRIs) with different polarities and charge properties. It is often a challenge to develop selective and robust high performance liquid chromatography (HPLC) methods for the efficient separation of all DRIs. In this study, an analytical quality by design (AQbD) approach was proposed for stability-indicating method development of cloxacillin. The structures, retention and UV characteristics rules of penicillins and their impurities were summarized and served as useful prior knowledge. Through quality risk assessment and screen design, 3 critical process parameters (CPPs) were defined, including 2 mixture variables (MVs) and 1 process variable (PV). A combined mixture-process variable (MPV) design was conducted to evaluate the 3 CPPs simultaneously and a response surface methodology (RSM) was used to achieve the optimal experiment parameters. A dual gradient elution was performed to change buffer pH, mobile-phase type and strength simultaneously. The design spaces (DSs) was evaluated using Monte Carlo simulation to give their possibility of meeting the specifications of CQAs. A Plackett-Burman design was performed to test the robustness around the working points and to decide the normal operating ranges (NORs). Finally, validation was performed following International Conference on Harmonisation (ICH) guidelines. To our knowledge, this is the first study of using MPV design and dual gradient elution to develop HPLC methods and improve separations for complex ionic samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Micropollutant degradation, bacterial inactivation and regrowth risk in wastewater effluents: Influence of the secondary (pre)treatment on the efficiency of Advanced Oxidation Processes.

    Science.gov (United States)

    Giannakis, Stefanos; Voumard, Margaux; Grandjean, Dominique; Magnet, Anoys; De Alencastro, Luiz Felippe; Pulgarin, César

    2016-10-01

    In this work, disinfection by 5 Advanced Oxidation Processes was preceded by 3 different secondary treatment systems present in the wastewater treatment plant of Vidy, Lausanne (Switzerland). 5 AOPs after two biological treatment methods (conventional activated sludge and moving bed bioreactor) and a physiochemical process (coagulation-flocculation) were tested in laboratory scale. The dependence among AOPs efficiency and secondary (pre)treatment was estimated by following the bacterial concentration i) before secondary treatment, ii) after the different secondary treatment methods and iii) after the various AOPs. Disinfection and post-treatment bacterial regrowth were the evaluation indicators. The order of efficiency was Moving Bed Bioreactor > Activated Sludge > Coagulation-Flocculation > Primary Treatment. As far as the different AOPs are concerned, the disinfection kinetics were: UVC/H2O2 > UVC and solar photo-Fenton > Fenton or solar light. The contextualization and parallel study of microorganisms with the micropollutants of the effluents revealed that higher exposure times were necessary for complete degradation compared to microorganisms for the UV-based processes and inversed for the Fenton-related ones. Nevertheless, in the Fenton-related systems, the nominal 80% removal of micropollutants deriving from the Swiss legislation, often took place before the elimination of bacterial regrowth risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Degradation process modelization in of metallic drink containers, in soil, in water and in water-soil interaction

    International Nuclear Information System (INIS)

    Rieiro, I.; Trivino, V.; Gutierrez, T.; Munoz, J.; Larrea, M. T.

    2013-01-01

    This study asses the environmental pollution by metal release that takes place during prolonged exposures when metallic drink containers are accidentally settle in the soil in a uncontrolled way, For comparative purposes, the F111 steel and the aluminium alloy 3003, widely used for the fabrication of these containers, are also considered. A experimental design is proposed to simulate the environmental pollution during prolonged exposures. Analytical indicators have been obtained determining the metallic concentration from three types of mediums; water, water in presence of soil, and absorption-adsorption in soil. An analytical methodology has been developed by Atomic Emission Spectrometry with ICP as exciting source (ICP-OES) for metallic quantification. The method was validated using Certified Reference Materials (CRMs) of soil and water and the precision obtained varies from 5.39 to 5.86% and from 5.75 to 6.27%, respectively according to of the element studied. A statistical descriptive study followed by a factorial analysis (linear general model) has been carried out for the treatment of the experimental data packages. The metallic quantification for the three mediums shows that the soil inhibits metallic solubility in water. The process to make packages reduces in both cases their metallic cession. (Author)

  2. Podocytes Degrade Endocytosed Albumin Primarily in Lysosomes

    Science.gov (United States)

    Carson, John M.; Okamura, Kayo; Wakashin, Hidefumi; McFann, Kim; Dobrinskikh, Evgenia; Kopp, Jeffrey B.; Blaine, Judith

    2014-01-01

    Albuminuria is a strong, independent predictor of chronic kidney disease progression. We hypothesize that podocyte processing of albumin via the lysosome may be an important determinant of podocyte injury and loss. A human urine derived podocyte-like epithelial cell (HUPEC) line was used for in vitro experiments. Albumin uptake was quantified by Western blot after loading HUPECs with fluorescein-labeled (FITC) albumin. Co-localization of albumin with lysosomes was determined by confocal microscopy. Albumin degradation was measured by quantifying FITC-albumin abundance in HUPEC lysates by Western blot. Degradation experiments were repeated using HUPECs treated with chloroquine, a lysosome inhibitor, or MG-132, a proteasome inhibitor. Lysosome activity was measured by fluorescence recovery after photo bleaching (FRAP). Cytokine production was measured by ELISA. Cell death was determined by trypan blue staining. In vivo, staining with lysosome-associated membrane protein-1 (LAMP-1) was performed on tissue from a Denys-Drash trangenic mouse model of nephrotic syndrome. HUPECs endocytosed albumin, which co-localized with lysosomes. Choloroquine, but not MG-132, inhibited albumin degradation, indicating that degradation occurs in lysosomes. Cathepsin B activity, measured by FRAP, significantly decreased in HUPECs exposed to albumin (12.5% of activity in controls) and chloroquine (12.8%), and declined further with exposure to albumin plus chloroquine (8.2%, palbumin and chloroquine alone, and these effects were potentiated by exposure to albumin plus chloroquine. Compared to wild-type mice, glomerular staining of LAMP-1 was significantly increased in Denys-Drash mice and appeared to be most prominent in podocytes. These data suggest lysosomes are involved in the processing of endocytosed albumin in podocytes, and lysosomal dysfunction may contribute to podocyte injury and glomerulosclerosis in albuminuric diseases. Modifiers of lysosomal activit