WorldWideScience

Sample records for degraded viewing conditions

  1. Research of Isolation and Degradation Conditions of Petroleum Degrading Marine

    Science.gov (United States)

    Fangrui, Guo

    2017-01-01

    A novel petroleum-degrading microbial strain was isolated from sediment samples in estuary of Bohai Sea estuary beaches. The strain was primarily identified as Alcanivorax sp. and named Alcanivorax sp. H34. Effect of PH values, temperature, nitrogen and phosphorus concentrations on degradation of H34 were investigated. The paraffinic components average degradation rate of H34 ungrowth cells under optimized conditions was studied. The results showed that the optimal growth conditions of H34 are were temperature of 30°C, initial PH of 7.0, nitrogen concentration of 3g/L, phosphorus concentration of 3g/L, and paraffinic components average degradation rates of H34 ungrowth cells was 41.6%, while total degradation rate was 45.5%.

  2. 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

  3. Degradation In Relation To Environmental Conditions

    Science.gov (United States)

    Putters, B.

    One of the parts of the natural attenuation capacity of the soil is its degradation ca- pacity. Usually, the degradation capacity is determined by monitoring contaminant concentrations in the field. However, it is desirable to estimate the degradation ca- pacity of a soil beforehand. For such an estimate, the factors which have the highest influence on the degradation process of a specific contaminant must be known. To find the soil parameters which dominate the degradation behaviour of contaminants in the subsurface, an approach is proposed. The approach consists of 3 steps 1. Derive expected patterns of behaviour under different environmental conditions from litera- ture review. 2. Collect data from published degradation experiments. 3. Explore the dataset by means of statistical techniques. The expected patterns of behaviour are used as guidelines for the exploration of the dataset. Three types of results are derived from dataset exploration: 1. The degree of influence of a variable on the degradation rate is found by application of the analysis- of-variance technique. 2. Factors, summarizing the variables under consideration, can be derived by application of principal components analysis. 3. Relationships can be quantified for the whole dataset or for subsets of the dataset by regression analysis. The approach has been applied to atrazine degradation experiments (see also abstract EGS02-A-01204 for poster presentation). The results will be used as an example and to illustrate problems and solutions during processing. This project is part of a Ph.D. study carried out in the framework of Delft Cluster during the period 1999-2003.

  4. Fungal degradation of nitrocellulose under aerobic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, A.; Sundaram, S.T.; Zhang, Y.Z. [Geo-Centers, Inc., Lake Hopatcong, NJ (United States); Brodman, B.W. [Armaments Research Development and Engineering Center, Picatinny Arsenal, NJ (United States)

    1995-12-31

    Mycelial fungi were screened alone or in combinations for their ability to degrade nitrocellulose (3 g/L) in liquid medium. All of the fungi tested used nitrocellulose to a varying extent, but a combination of Sclerotium rolfsii ATCC 24459 and Fusarium solani IFO 31093 was found to be the best because it significantly degraded nitrocellulose. About 38% of the nitrocellulose was degraded by these fungi in a 7-day period when the culture medium was buffered at pH 6.0 with morphilino ethane sulfonic acid.

  5. Nitroglycerin degradation mediated by soil organic carbon under aerobic conditions.

    Science.gov (United States)

    Bordeleau, Geneviève; Martel, Richard; Bamba, Abraham N'Valoua; Blais, Jean-François; Ampleman, Guy; Thiboutot, Sonia

    2014-10-01

    The presence of nitroglycerin (NG) has been reported in shallow soils and pore water of several military training ranges. In this context, NG concentrations can be reduced through various natural attenuation processes, but these have not been thoroughly documented. This study aimed at investigating the role of soil organic matter (SOM) in the natural attenuation of NG, under aerobic conditions typical of shallow soils. The role of SOM in NG degradation has already been documented under anoxic conditions, and was attributed to SOM-mediated electron transfer involving different reducing agents. However, unsaturated soils are usually well-oxygenated, and it was not clear whether SOM could participate in NG degradation under these conditions. Our results from batch- and column-type experiments clearly demonstrate that in presence of dissolved organic matter (DOM) leached from a natural soil, partial NG degradation can be achieved. In presence of particulate organic matter (POM) from the same soil, complete NG degradation was achieved. Furthermore, POM caused rapid sorption of NG, which should result in NG retention in the organic matter-rich shallow horizons of the soil profile, thus promoting degradation. Based on degradation products, the reaction pathway appears to be reductive, in spite of the aerobic conditions. The relatively rapid reaction rates suggest that this process could significantly participate in the natural attenuation of NG, both on military training ranges and in contaminated soil at production facilities.

  6. Performance of BTX degraders under substrate versatility conditions.

    Science.gov (United States)

    Maliyekkal, Shihabudeen M; Rene, Eldon R; Philip, Ligy; Swaminathan, T

    2004-06-18

    A microbial consortium acclimatized with benzene, toluene or xylene (BTX) was employed to study the degradation pattern of these compounds individually under aerobic conditions. Batch and continuous experiments were conducted to evaluate the adaptability of the enriched cultures under substrate versatility conditions. The bio-kinetic parameters obtained under substrate versatility conditions were compared with those of a single substrate condition. Similar degradation patterns were observed for all the substrates with inhibition occurring at higher concentration (approximately 150 mg/L for benzene and xylene, and approximately 200 mg/L for toluene). Toluene degradation was highest, followed by benzene and xylene in the aqueous phase. Adaptation to a more toxic compound like benzene and xylene improved the utilization of toluene. On the other hand, microbes grown on a less toxic compound (toluene) grew at a lower rate in the presence of more toxic compounds. Suitable kinetic parameters such as micro(max) (maximum specific growth rate per hour), Ks (half saturation constant, mg/L), and KI (threshold substrate inhibition constant, mg/L) were determined using Haldane and Levenspiel substrate inhibition models. The Haldane equation seems to be an adequate expression for the system. The degradation behavior of pollutants in the gas phase was also evaluated using a toluene acclimatized biotrickling filter operated in continuous mode. The biotrickling filter acclimatized with toluene could degrade benzene and xylene with a lower elimination capacity. But, the system could recover its original efficiency quite fast even after a prolonged shock loading. The degradation was better for toluene, followed by benzene and xylene.

  7. Material degradation - a nuclear utility's view

    Energy Technology Data Exchange (ETDEWEB)

    Spekkens, P. [Ontario Power Generation, Science and Technology Development, Toronto, Ontario (Canada)

    2007-07-01

    Degradation of nuclear plant materials has been responsible for major costs and unit outage time. As such, nuclear utilities are important end users of the information produced by R and D on material degradation. This plenary describes the significance of material degradation for the nuclear utilities, and how utilities use information about material degradation in their short, medium and long term planning activities. Utilities invest in R and D programs to assist them in their business objective of operating safely, reliably and cost competitively. Material degradation impacts all three of these business drivers. Utilities make decisions on life cycle planning, unit refurbishment and 'new build' projects on the basis of their understanding of the behaviour of a variety of materials in a broad range of environments. The R and D being carried out today will determine the future business success of the nuclear utilities. The R and D program needs to be broadly based to include a range of materials, environments and time-frames, particularly any new materials proposed for use in new units. The R and D community needs to help the utility managers make choices that will result in an optimized materials R and D program.

  8. Degradation of toxaphene in water during anaerobic and aerobic conditions.

    Science.gov (United States)

    LacayoR, M; van Bavel, B; Mattiasson, B

    2004-08-01

    The degradation of technical toxaphene in water with two kinds of bioreactors operating in sequence was studied. One packed bed reactor was filled with Poraver (foam glass particles) running at anaerobic conditions and one suspended carrier biofilm reactor working aerobically. Chemical oxygen demand (COD), chloride, sulphate, pH, dissolved oxygen, total toxaphene and specific toxaphene isomers were measured. After 6 weeks approx. 87% of the total toxaphene was degraded reaching 98% by week 39. The majority of the conversion took place in the anaerobic reactor. The concentrations of toxaphene isomers with more chlorine substituents decreased more rapidly than for isomers with less chlorine substituents.

  9. Degradation of hydrocarbons under methanogenic conditions in different geosystems

    Science.gov (United States)

    Straaten, Nontje; Jiménez García, Núria; Richnow, Hans-Hermann; Krueger, Martin

    2014-05-01

    With increasing energy demand the search for new resources is becoming increasingly important for the future energy supply. Therefore the knowledge about fossil fuels like oil or natural gas and their extraction should be expanded. Biodegraded oil is found in many reservoirs worldwide. Consequently, it is very important to get insight in the microbial communities and metabolic processes involved in hydrocarbon degradation. Due to the lack of alternative electron acceptors in hydrocarbon-rich geosystems, degradation often takes place under methanogenic conditions. The aim of the present study is to identify the microorganisms and mechanisms involved in the degradation of complex hydrocarbons, like BTEX and polycyclic aromatic hydrocarbons, using culture dependent and independent techniques. For this purpose enrichment cultures from marine sediments, shales, coal and oil reservoirs are monitored for their capability to degrade alkanes and aromatic compounds. Moreover the environmental samples of these different geosystems analysed for evidence for the in situ occurrence of methanogenic oil degradation. The gas geochemical data provided in several cases hints for a recent biological origin of the methane present. First results of the microbial community analysis showed in environmental samples and enrichment cultures the existence of Bacteria known to degrade hydrocarbons. Also a diverse community of methanogenic Archaea could be found in the clone libraries. Additionally, in oil and coal reservoir samples the degradation of model hydrocarbons, e.g. methylnaphthalene, hexadecane and BTEX, to CH4 was confirmed by 13C-labeling. To explore the mechanisms involved in biodegradation, the enrichments as well as the original environmental samples are further analysed for the presence of respective functional genes.

  10. 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.; DeVincenzi, Donald (Technical Monitor)

    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.

  11. Effects of Different Viewing Conditions on Radiographic Interpretation

    Directory of Open Access Journals (Sweden)

    Mahkameh Moshfeghi

    2016-08-01

    Full Text Available Objectives: Optimum viewing conditions facilitate identification of radiographic details and decrease the need for retakes, patients’ costs and radiation dose. This study sought to evaluate the effects of different viewing conditions on radiographic interpretation.Materials and Methods: This diagnostic study was performed by evaluating radiograph of a 7mm-thick aluminum block, in which 10 holes with 2mm diameters were randomly drilled with depths ranging from 0.05 mm to 0.50mm. The radiograph was viewed by four oral radiologists independently under four viewing conditions, including a white light viewing light box in a lit room, yellow light viewing light box in a lit room, white light viewing light box in a dark room and yellow light viewing light box in a dark room. Number of circular shadows observed on the film was recorded. The data were analyzed by two-way ANOVA.Results: The mean number of detected circular shadows was 6.75, 7.5, 7.25 and 7.75 in white light viewing light box in a lit room, white light viewing light box in a dark room, yellow light viewing light box in a lit room and yellow light viewing light box in a dark room, respectively. Although the surrounding illumination had statistically significant effect on the radiographic details (P≤0.03, the light color of the viewing light box had no significant effect on visibility of the radiographic details.Conclusion: White and yellow light of the viewing light box had no significant effect on visibility of the radiographic details but more information was obtained in a dark room.

  12. Effects of Different Viewing Conditions on Radiographic Interpretation.

    Science.gov (United States)

    Moshfeghi, Mahkameh; Shahbazian, Majid; Sajadi, Soodabeh Sadat; Sajadi, Sepideh; Ansari, Hossein

    2015-11-01

    Optimum viewing conditions facilitate identification of radiographic details and decrease the need for retakes, patients' costs and radiation dose. This study sought to evaluate the effects of different viewing conditions on radiographic interpretation. This diagnostic study was performed by evaluating radiograph of a 7mm-thick aluminum block, in which 10 holes with 2mm diameters were randomly drilled with depths ranging from 0.05 mm to 0.50mm. The radiograph was viewed by four oral radiologists independently under four viewing conditions, including a white light viewing light box in a lit room, yellow light viewing light box in a lit room, white light viewing light box in a dark room and yellow light viewing light box in a dark room. Number of circular shadows observed on the film was recorded. The data were analyzed by two-way ANOVA. The mean number of detected circular shadows was 6.75, 7.5, 7.25 and 7.75 in white light viewing light box in a lit room, white light viewing light box in a dark room, yellow light viewing light box in a lit room and yellow light viewing light box in a dark room, respectively. Although the surrounding illumination had statistically significant effect on the radiographic details (P≤0.03), the light color of the viewing light box had no significant effect on visibility of the radiographic details. White and yellow light of the viewing light box had no significant effect on visibility of the radiographic details but more information was obtained in a dark room.

  13. Microbial degradation of clomazone under simulated California rice field conditions.

    Science.gov (United States)

    Tomco, Patrick L; Holstege, Dirk M; Zou, Wei; Tjeerdema, Ronald S

    2010-03-24

    Clomazone (trade names Cerano and Command) is a popular herbicide used on California rice fields to control aquatic weeds. Its physicochemical characteristics indicate that it will persist primarily in the water column, where microbial degradation may drive its environmental fate. The objectives were to determine microbial degradation rates and compare the metabolic products under aerobic and anaerobic conditions similar to those in California rice fields during the summer. Time-series samples were extracted and analyzed by LC/MS/MS. Metabolic profiling revealed the following clomazone-derived transitions: m/z 240 --> 125 (clomazone), m/z 242 --> 125 (ring-open clomazone), m/z 256 --> 125 (5-hydroxyclomazone), m/z 256 --> 141 (aromatic hydroxyclomazone), m/z 268 --> 125 (unknown metabolite), and m/z 272 --> 141 (4'5-dihydroxyclomazone). Results indicate an anaerobic half-life of 7.9 days, with ring-open clomazone reaching 67.4% of application at 38 days. Aerobically, clomazone degraded more slowly (t(1/2) = 47.3 days), forming mostly soil-bound residues. Thus, under summer conditions, clomazone is likely to dissipate rapidly from fields via anaerobic degradation.

  14. Compression of perceived depth as a function of viewing conditions.

    Science.gov (United States)

    Nolan, Ann; Delshad, Rebecca; Sedgwick, Harold A

    2012-12-01

    The magnification produced by a low-vision telescope has been shown to compress perceived depth. Looking through such a telescope, however, also entails monocular viewing and visual field restriction, and these viewing conditions, taken together, were also shown to compress perceived depth. The research presented here quantitatively explores the separate effects of each of these viewing conditions on perceived depth. Participants made verbal estimates of the length, relative to the width, of rectangles presented in a controlled table-top setting. In experiment 1, the rectangles were either in the frontal plane or receding in depth, and they were viewed either binocularly or monocularly with an unrestricted field of view (FOV). In experiment 2, the rectangles were in depth and were viewed monocularly with an unrestricted FOV, a moderately (40 degrees) restricted FOV, or a severely (11.5 degrees) restricted FOV. Viewed in the frontal plane, either monocularly or binocularly, the vertical dimension was expanded by about 10%. Viewed in depth, with an unrestricted FOV, the (projectively vertical) depth dimension was compressed by 12% when seen binocularly or 24% when seen monocularly. A monocular moderately (40 degrees) restricted FOV was very similar to the unrestricted monocular FOV. A severely (11.5 degrees) restricted FOV, however, produced a substantially greater 44% compression of perceived depth. Even under near-optimal binocular viewing conditions, there is some compression of perceived depth. The compression found when viewing through a low-vision telescope has been shown to be substantially greater. In addition to the previously demonstrated contribution of telescopic magnification to this effect, we have now shown that the viewing conditions of monocularity and severely restricted (11.5 degrees) FOV can each produce substantial increments in the compression of perceived depth. We found, however, that a moderately restricted (40 degrees) FOV does not increase

  15. Degradation of Zearalenone by Essential Oils under In vitro Conditions

    Science.gov (United States)

    Perczak, Adam; Juś, Krzysztof; Marchwińska, Katarzyna; Gwiazdowska, Daniela; Waśkiewicz, Agnieszka; Goliński, Piotr

    2016-01-01

    Essential oils are volatile compounds, extracted from plants, which have a strong odor. These compounds are known for their antibacterial and antifungal properties. However, data concerning degradation of mycotoxins by these metabolites are very limited. The aim of the present study was to investigate the effect of essential oils (cedarwood, cinnamon leaf, cinnamon bark, white grapefruit, pink grapefruit, lemon, eucalyptus, palmarosa, mint, thymic, and rosemary) on zearalenone (ZEA) reduction under various in vitro conditions, including the influence of temperature, pH, incubation time and mycotoxin and essential oil concentrations. The degree of ZEA reduction was determined by HPLC method. It was found that the kind of essential oil influences the effectiveness of toxin level reduction, the highest being observed for lemon, grapefruit, eucalyptus and palmarosa oils, while lavender, thymic and rosemary oils did not degrade the toxin. In addition, the decrease in ZEA content was temperature, pH as well as toxin and essential oil concentration dependent. Generally, higher reduction was observed at higher temperature in a wide range of pH, with clear evidence that the degradation rate increased gradually with time. In some combinations (e.g., palmarosa oil at pH 6 and 4 or 20°C) a toxin degradation rate higher than 99% was observed. It was concluded that some of the tested essential oils may be effective in detoxification of ZEA. We suggested that essential oils should be recognized as an interesting and effective means of ZEA decontamination and/or detoxification. PMID:27563298

  16. DEGRADATION MODES OF ALLOY 22 IN YUCCA MOUNTAIN REPOSITORY CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; G.M. Gordon; R.B. Rebak

    2005-10-13

    The nuclear waste package design for Yucca Mountain (Nevada, USA), in its current configuration, consists of a double wall cylindrical container fabricated using a highly corrosion resistant Ni-based Alloy 22 for the outer barrier and type 316 stainless steel for the inner structural vessel. A mailbox-shaped drip shield fabricated primarily using Ti Grade 7 will cover the waste packages. The environmental degradation of the relevant materials have been extensively studied and modeled for over ten years. This paper reviews the state-of-the-art understanding of the degradation modes of Alloy 22 (N06022) due to its interaction with the predicted in-drift mountain conditions including temperature and types of electrolytes. Subjects discussed include thermal aging and phase stability, dry oxidation, general and localized corrosion, stress corrosion cracking and hydrogen induced cracking.

  17. Degradation Modes of Alloy 22 in Yucca Mountain Repository Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hua, F; Gordon, G M; Mon, K G; Rebak, R B

    2005-11-05

    The nuclear waste package design for Yucca Mountain (Nevada, USA), in its current configuration, consists of a double wall cylindrical container fabricated using a highly corrosion resistant Ni-based Alloy 22 for the outer barrier and type 316 stainless steel for the inner structural vessel. A mailbox-shaped drip shield fabricated primarily using Ti Grade 7 will cover the waste packages. The environmental degradation of the relevant materials have been extensively studied and modeled for over ten years. This paper reviews the state-of-the-art understanding of the degradation modes of Alloy 22 (N06022) due to its interaction with the predicted in-drift mountain conditions including temperature and types of electrolytes. Subjects discussed include thermal aging and phase stability, dry oxidation, general and localized corrosion, stress corrosion cracking and hydrogen induced cracking.

  18. Pentachlorophenol (PCP) degradation microorganism community structure under microaeration condition

    Institute of Scientific and Technical Information of China (English)

    Chen Yuancai; Hao Yuan; Fu Shiyu; Zhan Huaiyu

    2007-01-01

    The comparison of pentachlorophenol (PCP)degradation was conducted under micro-aeration and anaerobic condition with three series of batch experiment,results of which indicated that during micro-aeration condition co-immobilized of anaerobic granular sludge and isolated aerobic bacterial species could enhance the efficiency of PCP reduction through the synergism of aerobes and anaerobes reductive dechlorination and exchange of metabolites within the co-immobilized granular sludge.While during anaerobic condition,there was no great difference in the three series.The specific activities experiment further confirmed that strict anaerobes were not affected over the presence of micro aeration environment.Microorganism community construction of co-immobilized anaerobic granular sludge and the mixed isolated aerobic community was also deduced.By the efficient cooperation of aerobes and anaerobes,the high efficiency removal rate of PCP was implemented.

  19. Renewable Aromatics from the Degradation of Polystyrene under Mild Conditions

    KAUST Repository

    Al Jabri, Nouf M.

    2017-08-01

    Polystyrene (PS) is one of the most important polymers in the plastic sector due to its inexpensive cost as well as many preferred properties. Its international market is expected to achieve $28.2 billion by 2019. Although PS has a high calorific value of 87 GJ tonne-1, there is no a practical method to manage its waste but landfill. As a result, the PS debris in the oceans has reached 70% of the total plastic debris. This issue is considered as the main economical and environmental drivers of converting polystyrene waste into renewable chemical feedstocks. The aim of this work is to develop a catalyst for converting PS into renewable chemicals under mild conditions. We introduce FeCu/Alumina with excellent catalytic activity to fully degrade polystyrene with 66% liquid yield at 250 °C. The GC/MS confirmed that the primary products are in the gasoline range. Next, we present the bimetallic FeCo/Alumina and successfully we have obtained 100% PS conversion and 90% liquid yield with maintaining the products selectivity. Later, the tri-metallic FeCuCo/Alumina was synthesized and showed 100% PS conversion and 91% liquid yield. Surprisingly, ethylbenzene was the major product in which 80 wt. % was achieved with excellent reproducibility. Furthermore, the real waste Styrofoam was thermally and catalytically degraded at 250 °C. Interestingly, a high styrene content of 78 wt. % was recovered after 30 minutes of the reaction under mild conditions. Keeping in mind that a good balance between acidity and basicity is required to convert PS into aromatic under mild reaction conditions catalytically. Finally, the performance of the catalysts was compared to literature reports and showed novel liquid yields. In conclusion, we have synthesized cheap, easy to scale up, and efficient catalysts to fully degrade PS into high liquid yields of aromatics with excellent selectivity.

  20. Anaerobic degradation of citrate under sulfate reducing and methanogenic conditions.

    Science.gov (United States)

    Gámez, Victor M; Sierra-Alvarez, Reyes; Waltz, Rebecca J; Field, James A

    2009-07-01

    Citrate is an important component of metal processing effluents such as chemical mechanical planarization wastewaters of the semiconductor industry. Citrate can serve as an electron donor for sulfate reduction applied to promote the removal of metals, and it can also potentially be used by methanogens that coexist in anaerobic biofilms. The objective of this study was to evaluate the degradation of citrate with sulfate-reducing and methanogenic biofilms. During batch bioassays, the citrate, acetate, methane and sulfide concentrations were monitored. The results indicate that independent of the biofilm or incubation conditions used, citrate was rapidly fermented with specific rates ranging from 566 to 720 mg chemical oxygen demand (COD) consumed per gram volatile suspended solids per day. Acetate was found to be the main fermentation product of citrate degradation, which was later degraded completely under either methanogenic or sulfate reducing conditions. However, if either sulfate reduction or methanogenesis was infeasible due to specific inhibitors (2-bromoethane sulfonate), absence of sulfate or lack of adequate microorganisms in the biofilm, acetate accumulated to levels accounting for 90-100% of the citrate-COD consumed. Based on carbon balances measured in phosphate buffered bioassays, acetate, CO(2) and hydrogen are the main products of citrate fermentation, with a molar ratio of 2:2:1 per mol of citrate, respectively. In bicarbonate buffered bioassays, acetogenesis of H(2) and CO(2) increased the yield of acetate. The results taken as a whole suggest that in anaerobic biofilm systems, citrate is metabolized via the formation of acetate as the main metabolic intermediate prior to methanogenesis or sulfate reduction. Sulfate reducing consortia must be enriched to utilize acetate as an electron donor in order to utilize the majority of the electron-equivalents in citrate.

  1. Degradation in perovskite solar cells stored under different environmental conditions

    Science.gov (United States)

    Chauhan, Abhishek K.; Kumar, Pankaj

    2017-08-01

    Investigations carried out on the degradation of perovskite solar cells (PSCs) stored in different open air environmental conditions are reported here. The solar cells were stored in the open in the dark inside the laboratory (relative humidity 47  ±  5%, temperature 23  ±  4 °C), under compact fluorescent lamp (CFL) illumination (irradiance 10 mW cm2, relative humidity 47  ±  5%, temperature 23  ±  4 °C) and under natural sunlight outside the laboratory. In the outdoor storage situation the surrounding conditions varied from time to time and the environmental conditions during the day (irradiance 100 mW/cm2, relative humidity ~18%, temperature ~45 °C at noon) were entirely different from those at night (irradiance 0 mW/cm2, relative humidity ~66%, temperature ~16 °C at midnight). The photovoltaic parameters were measured from time to time inside the laboratory as per the International Summit on Organic Photovoltaic Stability (ISOS) protocols. All the photovoltaic parameters, such as short circuit current density (J sc), open circuit voltage (V oc), fill factor (FF) and power conversion efficiency (PCE), of the solar cells stored outdoors decayed more rapidly than those stored under CFL or in the dark. The solar cells stored in the dark exhibited maximum stability. While the encapsulated solar cells stored outdoors were completely dead after about 560 h, the solar cells stored under CFL illumination retained  >60% of their initial efficiency even after 1100 h. However, the solar cells stored in the dark and tested up to ~1100 h did not show any degradation in PCE but on the contrary exhibited slight improvement, and this improvement was mainly because of improvement in their V oc. Rapid degradation in the open air outside the laboratory under direct sunlight compared with the dark and CFL storage has been attributed to high temperature during the day, high humidity at night, high solar illumination intensity and the

  2. Modeling of Zircaloy cladding degradation under repository conditions

    Energy Technology Data Exchange (ETDEWEB)

    Santanam, L.; Raghavan, S.; Chin, B.A. [Auburn Univ., AL (USA). Dept. of Materials Engineering; Shaw, H. [Lawrence Livermore National Lab., CA (USA)

    1989-07-01

    Two potential degradation mechanisms, creep and stress corrosion cracking, of Zircaloy cladding during repository storage of spent nuclear fuel have been investigated. The deformation and fracture map methodology has been used to predict maximum allowable initial storage temperatures to achieve a thousand year life without rupture as a function of spent-fuel history. A stress analysis of fuel rods has been performed. Stresses in the outer zirconium oxide layer and the inner Zircaloy tube have been predicted for typical internal pressurization, oxide layer thickness, volume expansion from formation of the oxide layer and thermal expansion coefficients of the cladding and oxide. Stress relaxation occurring in-reactor has also been taken into account. The calculations indicate that for the anticipated storage conditions investigated, the outer zirconium oxide layer is in a state of compression thus making it unlikely that stress corrosion cracking of the exterior surface will occur. 20 refs., 6 figs., 9 tabs.

  3. Emotions' impact on viewing behavior under natural conditions.

    Science.gov (United States)

    Kaspar, Kai; Hloucal, Teresa-Maria; Kriz, Jürgen; Canzler, Sonja; Gameiro, Ricardo Ramos; Krapp, Vanessa; König, Peter

    2013-01-01

    Human overt attention under natural conditions is guided by stimulus features as well as by higher cognitive components, such as task and emotional context. In contrast to the considerable progress regarding the former, insight into the interaction of emotions and attention is limited. Here we investigate the influence of the current emotional context on viewing behavior under natural conditions.In two eye-tracking studies participants freely viewed complex scenes embedded in sequences of emotion-laden images. The latter primes constituted specific emotional contexts for neutral target images.Viewing behavior toward target images embedded into sets of primes was affected by the current emotional context, revealing the intensity of the emotional context as a significant moderator. The primes themselves were not scanned in different ways when presented within a block (Study 1), but when presented individually, negative primes were more actively scanned than positive primes (Study 2). These divergent results suggest an interaction between emotional priming and further context factors. Additionally, in most cases primes were scanned more actively than target images. Interestingly, the mere presence of emotion-laden stimuli in a set of images of different categories slowed down viewing activity overall, but the known effect of image category was not affected. Finally, viewing behavior remained largely constant on single images as well as across the targets' post-prime positions (Study 2).We conclude that the emotional context significantly influences the exploration of complex scenes and the emotional context has to be considered in predictions of eye-movement patterns.

  4. Heterogeneous photocatalytic degradation of gallic acid under different experimental conditions.

    Science.gov (United States)

    Quici, Natalia; Litter, Marta I

    2009-07-01

    UV/TiO(2)-heterogeneous photocatalysis was tested as a process to degrade gallic acid (Gal) in oxygenated solutions at pH 3. In the absence of oxidants other than oxygen, decay followed a zero order rate at different concentrations and was slow at concentrations higher than 0.5 mM. Addition of Fe(3+), H(2)O(2) and the combination Fe(3+)/H(2)O(2) improved Gal degradation. In the absence of H(2)O(2), an optimal Fe : Gal molar ratio of 0.33 : 1 was found for the photocatalytic decay, beyond which addition of Fe(3+) was detrimental and even worse in comparison with the system in the absence of Fe(3+). TiO(2) addition was beneficial compared with the same system in the absence of the photocatalyst if Fe(3+) was added at low concentration (0.33 : 1 Fe : Gal molar ratio), while at high concentration (1 : 1 Fe : Gal molar ratio) TiO(2) did not exert any significant effect. H(2)O(2) addition (1 : 0.33 Gal : H(2)O(2) molar ratio, absence of Fe(iii)) also enhanced the heterogeneous photocatalytic reaction. Simultaneous addition of Fe(3+) and H(2)O(2) was more effective than the addition of the separate oxidants. This system was compared with Fenton and photo-Fenton systems. At low H(2)O(2) concentration (0.33 : 1 : 0.2 Fe : Gal : H(2)O(2) molar ratio), the presence of TiO(2) also enhanced the reaction. The influence of the thermal charge transfer reaction between Gal and Fe(iii), which leads to an important Gal depletion in the dark with formation of quinones, was analysed. The mechanisms taking place in these complex systems are proposed, paying particular attention to the important charge transfer reaction of the Fe(iii)-Gal complex operative in dark conditions.

  5. Degradation of Artemisinin-Based Combination Therapies under Tropical Conditions

    Science.gov (United States)

    Hall, Zoe; Allan, Elizabeth Louise; van Schalkwyk, Donelly Andrew; van Wyk, Albert; Kaur, Harparkash

    2016-01-01

    Poor quality antimalarials, including falsified, substandard, and degraded drugs, are a serious health concern in malaria-endemic countries. Guidelines are lacking on how to distinguish between substandard and degraded drugs. “Forced degradation” in an oven was carried out on three common artemisinin-based combination therapy (ACT) brands to detect products of degradation using liquid chromatography mass spectrometry and help facilitate classification of degraded drugs. “Natural aging” of 2,880 tablets each of ACTs artemether/lumefantrine and artesunate/amodiaquine was undertaken to evaluate their long-term stability in tropical climates. Samples were aged in the presence and absence of light on-site in Ghana and in a stability chamber (London), removed at regular intervals, and analyzed to determine loss of the active pharmaceutical ingredients (APIs) over time and detect products of degradation. Loss of APIs in naturally aged tablets (both in Ghana and the pharmaceutical stability chamber) was 0–7% over 3 years (∼12 months beyond expiry) with low levels of degradation products detected. Using this developed methodology, it was found that a quarter of ACTs purchased in Enugu, Nigeria (concurrent study), that would have been classified as substandard, were in fact degraded. Presence of degradation products together with evidence of insufficient APIs can be used to classify drugs as degraded. PMID:26951346

  6. Emotions' impact on viewing behavior under natural conditions.

    Directory of Open Access Journals (Sweden)

    Kai Kaspar

    Full Text Available Human overt attention under natural conditions is guided by stimulus features as well as by higher cognitive components, such as task and emotional context. In contrast to the considerable progress regarding the former, insight into the interaction of emotions and attention is limited. Here we investigate the influence of the current emotional context on viewing behavior under natural conditions.In two eye-tracking studies participants freely viewed complex scenes embedded in sequences of emotion-laden images. The latter primes constituted specific emotional contexts for neutral target images.Viewing behavior toward target images embedded into sets of primes was affected by the current emotional context, revealing the intensity of the emotional context as a significant moderator. The primes themselves were not scanned in different ways when presented within a block (Study 1, but when presented individually, negative primes were more actively scanned than positive primes (Study 2. These divergent results suggest an interaction between emotional priming and further context factors. Additionally, in most cases primes were scanned more actively than target images. Interestingly, the mere presence of emotion-laden stimuli in a set of images of different categories slowed down viewing activity overall, but the known effect of image category was not affected. Finally, viewing behavior remained largely constant on single images as well as across the targets' post-prime positions (Study 2.We conclude that the emotional context significantly influences the exploration of complex scenes and the emotional context has to be considered in predictions of eye-movement patterns.

  7. Dynamics of the near response under natural viewing conditions with an open-view sensor.

    Science.gov (United States)

    Chirre, Emmanuel; Prieto, Pedro; Artal, Pablo

    2015-10-01

    We have studied the temporal dynamics of the near response (accommodation, convergence and pupil constriction) in healthy subjects when accommodation was performed under natural binocular and monocular viewing conditions. A binocular open-view multi-sensor based on an invisible infrared Hartmann-Shack sensor was used for non-invasive measurements of both eyes simultaneously in real time at 25Hz. Response times for each process under different conditions were measured. The accommodative responses for binocular vision were faster than for monocular conditions. When one eye was blocked, accommodation and convergence were triggered simultaneously and synchronized, despite the fact that no retinal disparity was available. We found that upon the onset of the near target, the unblocked eye rapidly changes its line of sight to fix it on the stimulus while the blocked eye moves in the same direction, producing the equivalent to a saccade, but then converges to the (blocked) target in synchrony with accommodation. This open-view instrument could be further used for additional experiments with other tasks and conditions.

  8. Varying Conditions for Hexanoic Acid Degradation with BioTiger™

    Energy Technology Data Exchange (ETDEWEB)

    Foreman, Koji [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Milliken, Charles [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brigmon, Robin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    BioTiger™ (BT) is a consortium of 12 bacteria designed for petroleum waste biodegradation. BT is currently being studied and could be considered for bioremediation of the Athabasca oil sands refineries in Canada and elsewhere. The run off ponds from the petroleum extraction processes, called tailings ponds, are a mixture of polycyclic aromatic hydrocarbons, naphthenic acids, hydrocarbons, toxic chemicals like heavy metals, water, and sand. Due to environmental regulations the oil industry would like to separate and degrade the hazardous chemical species from the tailings ponds while recycling the water. It has been shown that BT at 30 C° is able to completely degrade 10 mM hexanoic acid (HA) cometabolically with 0.2% yeast extract (w/v) in 48 hours when starting at 0.4 OD 600nm. After establishing this stable degradation capability, variations were tested to explore the wider parameters of BT activity in temperature, pH, intermediate degradation, co-metabolic dependence, and transfer stability. Due to the vast differences in temperature at various points in the refineries, a wide range of temperatures were assessed. The results indicate that BT retains the ability to degrade HA, a model surrogate for tailings pond contaminants, at temperatures ranging from 15°C to 35°C. Hexanamide (HAM) was shown to be an intermediate generated during the degradation of HA in an earlier work and HAM is completely degraded after 48 hours, indicating that HAM is not the final product of HA degradation. Various replacements for yeast extract were attempted. Glucose, a carbon source; casein amino acids, a protein source; additional ammonia, mimicking known media; and additional phosphate with Wolffe’s vitamins and minerals all showed no significant degradation of HA compared to control. Decreasing the yeast extract concentration (0.05%) demonstrated limited but significant degradation. Finally, serial inoculations of BT were performed to determine the stability of degradation

  9. Varying Conditions for Hexanoic Acid Degradation with BioTiger™

    Energy Technology Data Exchange (ETDEWEB)

    Foreman, Koji [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Milliken, Charles [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brigmon, Robin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    BioTiger™ (BT) is a consortium of 12 bacteria designed for petroleum waste biodegradation. BT is currently being studied and could be considered for bioremediation of the Athabasca oil sands refineries in Canada and elsewhere. The run-off ponds from the petroleum extraction processes, called tailings ponds, are a mixture of polycyclic aromatic hydrocarbons, naphthenic acids, hydrocarbons, toxic chemicals like heavy metals, water, and sand. Due to environmental regulations the oil industry would like to separate and degrade the hazardous chemical species from the tailings ponds while recycling the water. It has been shown that BT at 30 C° is able to completely degrade 10 mM hexanoic acid (HA) co-metabolically with 0.2% yeast extract (w/v) in 48 hours when starting at 0.4 OD 600nm. After establishing this stable degradation capability, variations were tested to explore the wider parameters of BT activity in temperature, pH, intermediate degradation, co-metabolic dependence, and transfer stability. Due to the vast differences in temperature at various points in the refineries, a wide range of temperatures were assessed. The results indicate that BT retains the ability to degrade HA, a model surrogate for tailings pond contaminants, at temperatures ranging from 15°C to 35°C. Hexanamide (HAM) was shown to be an intermediate generated during the degradation of HA in an earlier work and HAM is completely degraded after 48 hours, indicating that HAM is not the final product of HA degradation. Various replacements for yeast extract were attempted. Glucose, a carbon source; casein amino acids, a protein source; additional ammonia, mimicking known media; and additional phosphate with Wolffe’s vitamins and minerals all showed no significant degradation of HA compared to control. Decreasing the yeast extract concentration (0.05%) demonstrated limited but significant degradation. Finally, serial inoculations of BT were performed to determine the stability of degradation

  10. Degradation of phenanthrene-analogue azaarenes by Mycobacterium gilvum strain LB307T under aerobic conditions.

    Science.gov (United States)

    Willumsen, P A; Nielsen, J K; Karlson, U

    2001-08-01

    A polycyclic aromatic hydrocarbon degrading Mycobacterium gilvum, strain LB307T, was able to degrade the azaarenes 5,6-benzoquinoline, 7,8-benzoquinoline, and phenanthridine (nitrogen-containing heterocyclic aromatic hydrocarbons) under aerobic conditions. The strain was able to use 5,6-benzoquinoline as sole sources of carbon, nitrogen, and energy. However, inhibition of degradation and growth was observed with increasing substrate concentration. During degradation, metabolites built up transiently. One of the metabolites detected during 5,6-benzoquinoline degradation is suggested to be 2-oxo-5,6-benzoquinoline. This is the first report on bacterial degradation of phenanthrene-analogue azaarenes.

  11. Nitrate dependent salicylate degradation by Pseudomonas butanovora under anaerobic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kesseru, P.; Kiss, I.; Bihari, Z.; Pal, K.; Portoeroe, P.; Polyak, B. [Bay Zoltan Foundation for Applied Research, Szeged (Hungary). Inst. for Biotechnology

    2005-05-01

    Nitrate-dependent salicylate degradation by the denitrifying Pseudomonas butanovora was investigated and the molar ratio of the cometabolism under anaerobic circumstances was determined. The bacterium was able to utilize salicylate as an electron donor for the reduction of nitrate. Salicylate was eliminated via catechol, which is degraded by means of catechol 2,3-oxygenases (meta-cleavage), forming 2-hydroxymuconic semialdehyde. The molar ratios of NO{sub 3}{sup -}-N:salicylate existing during the experiment accorded well with the assumed 1:1 molar ratio. The tolerances of the growth, the salicylate degradation and the denitrification of P. butanovora to various heavy metal ions were also studied. Although the strain was tolerant to Pb{sup 2+} and Cu{sup 2+} up to 1 mM in complete medium, salicylate utilization took place only up to a concentration of 0.1 mM for both heavy metal ions. Of the heavy metal ions investigated, Cd{sup 2+} (at a concentration of 0.05 mM) displayed the highest inhibitory effect on salicylate degradation by P. butanovora. (author)

  12. Bearing Condition Recognition and Degradation Assessment under Varying Running Conditions Using NPE and SOM

    Directory of Open Access Journals (Sweden)

    Shaohui Zhang

    2014-01-01

    Full Text Available Manifold learning methods have been widely used in machine condition monitoring and fault diagnosis. However, the results reported in these studies focus on the machine faults under stable loading and rotational speeds, which cannot interpret the practical machine running. Rotating machine is always running under variable speeds and loading, which makes the vibration signal more complicated. To address such concern, the NPE (neighborhood preserving embedding is applied for bearing fault classification. Compared with other algorithms (PCA, LPP, LDA, and ISOP, the NPE performs well in feature extraction. Since the traditional time domain signal denoising is time consuming and memory consuming, we denoise the signal features directly in feature space. Furthermore, NPE and SOM (self-organizing map are combined to assess the bearing degradation performance. Simulation and experiment results validate the effectiveness of the proposed method.

  13. Pulse decomposition-based analysis of PAT/TAT error caused by negative lobes in limited-view conditions

    Institute of Scientific and Technical Information of China (English)

    刘良兵; 陶超; 刘晓峻; 李先利; 张海涛

    2015-01-01

    Pulse decomposition has been proven to be efficient to analyze the complicated signals and it is introduced into the photoacoustic and thermoacoustic tomography to eliminate reconstruction distortions caused by negative lobes. During image reconstruction, negative lobes bring errors in the estimation of acoustic pulse amplitude, which is closely related to the distribution of absorption coefficient. The negative lobe error degrades imaging quality seriously in limited-view conditions because it cannot be offset so well as in full-view conditions. Therefore, a pulse decomposition formula is provided with detailed deduction to eliminate the negative lobe error and is incorporated into the popular delay-and-sum method for better reconstructing the image without additional complicated computation. Numerical experiments show that the pulse decomposition improves the image quality obviously in the limited-view conditions, such as separating adjacent absorbers, discovering a small absorber despite disturbance from a big absorber nearby, etc.

  14. Degradation of aromatic compounds in plants grown under aseptic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mithaishvili, T.; Ugrekhelidze, D.; Tsereteli, B.; Sadunishvili, T.; Kvesitadze, G. [Durmishidze Inst. of Biochemistry and Biotechnology, Academy of Sciences of Georgia, Tbilisi (Georgia); Scalla, R. [Lab. des Xenobiotiques, INRA, Toulouse (France)

    2005-02-01

    The aim of the work is to investigate the ability of higher plants to absorb and detoxify environmental pollutants - aromatic compounds via aromatic ring cleavage. Transformation of {sup 14}C specifically labelled benzene derivatives, [1-6-{sup 14}C]-nitrobenzene, [1-6-{sup 14}C]-aniline, [1-{sup 14}C]- and [7-{sup 14}C]-benzoic acid, in axenic seedlings of maize (Zea mays L.), kidney bean (Phaseolus vulgaris L.), pea (Pisum sativum L.) and pumpkin (Cucurbita pepo L.) were studied. After penetration in plants, the above xenobiotics are transformed by oxidative or reductive reactions, conjugation with cell endogenous compounds, and binding to biopolymers. The initial stage of oxidative degradation consists in hydroxylation reactions. The aromatic ring can then be cleaved and degraded into organic acids of the Krebs cycle. Ring cleavage is accompanied by {sup 14}CO{sub 2} evolution. Aromatic ring cleavage in plants has thus been demonstrated for different xenobiotics carrying different substitutions on their benzene ring. Conjugation with low molecular peptides is the main pathway of aromatic xenobiotics detoxification. Peptide conjugates are formed both by the initial xenobiotics (except nitrobenzene) and by intermediate transformation products. The chemical nature of the radioactive fragment and the amino acid composition of peptides participating in conjugation were identified. (orig.)

  15. Lipid-derived aldehyde degradation under thermal conditions.

    Science.gov (United States)

    Zamora, Rosario; Navarro, José L; Aguilar, Isabel; Hidalgo, Francisco J

    2015-05-01

    Nucleophilic degradation produced by reactive carbonyls plays a major role in food quality and safety. Nevertheless, these reactions are complex because reactive carbonyls are usually involved in various competitive reactions. This study describes the thermal degradation of 2-alkenals (2-pentenal and 2-octenal) and 2,4-alkadienals (2,4-heptadienal and 2,4-decadienal) in an attempt to both clarify the stability of aldehydes and determine new compounds that might also play a role in nucleophile/aldehyde reactions. The obtained results showed that alkenals and alkadienals decomposed rapidly in the presence of buffer and air to produce formaldehyde, acetaldehyde, and the aldehydes corresponding to the breakage of the carboncarbon double bonds: propanal, hexanal, 2-pentenal, 2-octenal, glyoxal, and fumaraldehyde. The activation energy of double bond breakage was relatively low (∼ 25 kJ/mol) and the yield of alkanals (10-18%) was higher than that of 2-alkenals (∼ 1%). All these results indicate that these reactions should be considered in order to fully understand the range of nucleophile/aldehyde adducts produced.

  16. Conditions for selective degradation of lignin by the fungus Ganoderma australis

    Energy Technology Data Exchange (ETDEWEB)

    Rios, S.; Eyzaguirre, J. (Universidad Catolica de Chile, Santiago (Chile). Lab. de Bioquimica)

    1992-08-01

    The white-rot fungus Ganoderma australis selectively degrades lignin in the ecosystem 'palo podrido'. Using conditions that simulate those of 'palo podrido' in the laboratory, it was found that low nitrogen content and low O{sub 2} tension stimulate the production of manganese peroxidase and lignin degradation, and depress cellulose degradation and cellulase production. The inverse is found at high nitrogen concentration and high O{sub 2} tension. This agrees with previous results indicating that low O{sub 2} tension and low nitrogen stimulate selective lignin degradation by this fungus. (orig.).

  17. Influence of water solubility, side chain degradability and side chain configuration on the degradation of phthalic acid esters under methanogenic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Alnervik, M.

    1996-12-31

    Water solubility and degradability of side chains estrifying phthalic acid are factors possible to influence the degradation of phthalic acid esters (PAEs). To investigate the importance of these factors degradation of butyl 2-ethylhexyl phthalate (BEHP), bis(2-ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), dihexyl phthalate (DHP), dioctyl phthalate (DOP) and didecyl phthalate (DDP) were examined under methanogenic conditions as well as was the degradability of the alcohols estrifying these PAEs. We also investigated if the degradation of resistant PAEs could be stimulated by the addition of a degradable PAE. Synthesis of degradation intermediates and two methods for PAE analyses are presented. The investigation showed that all alcohols were degraded to methane and carbon dioxide and that the degradation of PAE occurred in incubations amended with BBP, BEHP, DHP and DBP, whilst DEHP, DOP and DDP were unaffected throughout the experimental period. BBP added to incubations with DEHP, could not stimulate DEHP degradation. In conclusion, the degradability of alcohols estrifying phthalic acid in this study does not affect the anaerobic degradability of PAEs. Water solubility of a PAE can not be rejected as a factor limiting phthalate degradation under methanogenic conditions. Anaerobic degradation of persistent PAEs can not be stimulated by mixing it with a degradable phthalate. 23 refs, 11 figs, 2 tabs

  18. Exploration of Experimental Data On Atrazine Degradation In Relation To Environmental Conditions

    Science.gov (United States)

    Putters, B.

    The objective of this project is to find the soil factors which dominate the degradation behaviour of atrazine (pesticide). From published experiments on atrazine degradation in the subsurface, the available data concerning soil characteristics, experimental conditions, and the measured degra- dation rates were put into a database. From literature, environmental conditions could be related to degradation rates. These relationships were tested by exploration of the dataset by statistical techniques. In general, the degradation is mainly determined by the availability of the substrate (atrazine) and the biological activity. More specific re- lationships could be derived from the dataset and will be presented at the conference. The relationships can also be used for degradation rate estimates for modelling pur- poses.

  19. Degradation of the pharmaceuticals diclofenac and sulfamethoxazole and their transformation products under controlled environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Poirier-Larabie, S. [Aquatic Contaminants Research Division, Science and Water Technology Directorate, Environment Canada, Montréal, Québec H2Y 2E7 (Canada); Segura, P.A. [Department of Chemistry, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1 (Canada); Gagnon, C., E-mail: christian.gagnon@canada.ca [Aquatic Contaminants Research Division, Science and Water Technology Directorate, Environment Canada, Montréal, Québec H2Y 2E7 (Canada)

    2016-07-01

    Contamination of the aquatic environment by pharmaceuticals via urban effluents is well known. Several classes of drugs have been identified in waterways surrounding these effluents in the last 15 years. To better understand the fate of pharmaceuticals in ecosystems, degradation processes need to be investigated and transformation products must be identified. Thus, this study presents the first comparative study between three different natural environmental conditions: photolysis and biodegradation in aerobic and anaerobic conditions both in the dark of diclofenac and sulfamethoxazole, two common drugs present in significant amounts in impacted surface waters. Results indicated that degradation kinetics differed depending on the process and the type of drug and the observed transformation products also differed among these exposure conditions. Diclofenac was nearly degraded by photolysis after 4 days, while its concentration only decreased by 42% after 57 days of exposure to bacteria in aerobic media and barely 1% in anaerobic media. For sulfamethoxazole, 84% of the initial concentration was still present after 11 days of exposure to light, while biodegradation decreased its concentration by 33% after 58 days of exposure under aerobic conditions and 5% after 70 days of anaerobic exposure. In addition, several transformation products were observed and persisted over time while others degraded in turn. For diclofenac, chlorine atoms were lost primarily in the photolysis, while a redox reaction was promoted by biodegradation under aerobic conditions. For sulfamethoxazole, isomerization was favored by photolysis while a redox reaction was also favored by the biodegradation under aerobic conditions. To summarize this study points out the occurrence of different transformation products under variable degradation conditions and demonstrates that specific functional groups are involved in the tested natural attenuation processes. Given the complexity of environmental

  20. Butachlor degradation in tropical soils: effect of application rate, biotic-abiotic interactions and soil conditions.

    Science.gov (United States)

    Pal, R; Das, P; Chakrabarti, K; Chakraborty, A; Chowdhury, A

    2006-01-01

    The degradative characteristics of butachlor (N-Butoxymethyl-2-chloro-2',6'-diethyla- cetanilide) were studied under controlled laboratory conditions in clay loam alluvial (AL) soil (Typic udifluvent) and coastal saline (CS) soil (Typic endoaquept) from rice cultivated fields. The application rates included field rate (FR), 2-times FR (2FR) and 10-times FR (10FR). The incubation study was carried out at 30 degrees C with and without decomposed cow manure (DCM) at 60% of maximum water holding capacity (WHC) and waterlogged soil condition. The half-life values depended on the soil types and initial concentrations of butachlor. Butachlor degraded faster in AL soil and in soil amended with DCM under waterlogged condition. Microbial degradation is the major avenue of butachlor degradation from soils.

  1. Isolation and characterization of heavy polycyclic aromatic hydrocarbon-degrading bacteria adapted to electrokinetic conditions.

    Science.gov (United States)

    Li, Fengmei; Guo, Shuhai; Hartog, Niels; Yuan, Ye; Yang, Xuelian

    2016-02-01

    Polycyclic aromatic hydrocarbon (PAH)-degrading bacteria capable of growing under electrokinetic conditions were isolated using an adjusted acclimation and enrichment procedure based on soil contaminated with heavy PAHs in the presence of an electric field. Their ability to degrade heavy PAHs under an electric field was individually investigated in artificially contaminated soils. The results showed that strains PB4 (Pseudomonas fluorescens) and FB6 (Kocuria sp.) were the most efficient heavy PAH degraders under electrokinetic conditions. They were re-inoculated into a polluted soil from an industrial site with a PAH concentration of 184.95 mg kg(-1). Compared to the experiments without an electric field, the degradation capability of Pseudomonas fluorescens and Kocuria sp. was enhanced in the industrially polluted soil under electrokinetic conditions. The degradation extents of total PAHs were increased by 15.4 and 14.0% in the electrokinetic PB4 and FB6 experiments (PB4 + EK and FB6 + EK) relative to the PB4 and FB6 experiments without electrokinetic conditions (PB4 and FB6), respectively. These results indicated that P. fluorescens and Kocuria sp. could efficiently degrade heavy PAHs under electrokinetic conditions and have the potential to be used for the electro-bioremediation of PAH-contaminated soil, especially if the soil is contaminated with heavy PAHs.

  2. Renewable Aromatics from the Degradation of Polystyrene under Mild Conditions

    KAUST Repository

    Jabri, Nouf M

    2017-05-25

    A bimetallic FeCu/alumina catalyst was prepared and characterized. It showed excellent catalytic activity to quantitatively convert polystyrene (PS) into aromatics at low temperatures. A clear goldish yellow liquid was produced at 250 °C in a batch reactor without distillation. A liquid yield of 66% in an inert environment was achieved without the formation of coke and gas by-products. An exposure time of 90 min. and a catalyst loading of 200 mg were considered as an optimum condition to minimize the styrene re-polymerization. The gas chromatography/ mass spectrometry (GC/MS) analysis confirms that the primary products are styrene, ethylbenzene, cumene, toluene and α-methylstyrene.

  3. Biological degradation and microbial function effect of norfloxacin in a soil under different conditions.

    Science.gov (United States)

    Yang, Ji-Feng; Ying, Guang-Guo; Liu, Shan; Zhou, Li-Jun; Zhao, Jian-Liang; Tao, Ran; Peng, Ping-An

    2012-01-01

    This paper investigated the degradation kinetics of norfloxacin in a soil, and its effects on soil respiration and nitrogen transformation under different conditions. Compared to the sterile control, the degradation rates of norfloxacin in the non-sterile soil were greatly enhanced, suggesting that microorganisms played a major role in the degradation. Accelerated degradation for norfloxacin in the soil was observed with decreasing concentrations (30 mg/kg to 5 mg/kg) with its half-life decreasing from 62 days to 31 days. Amending swine manure into the soil and increasing the soil moisture level enhanced the biological degradation of norfloxacin. No obvious inhibition of norfloxacin on soil respiration was observed in the soil, while only slight effect on nitrogen transformation was found. The results suggested that norfloxacin at the reported environmental concentrations (<100 mg/kg) would have little effect on microbial activity and functions in the soils.

  4. RDX degradation in bioaugmented model aquifer columns under aerobic and low oxygen conditions.

    Science.gov (United States)

    Fuller, Mark E; Hatzinger, Paul B; Condee, Charles W; Andaya, Christina; Rezes, Rachel; Michalsen, Mandy M; Crocker, Fiona H; Indest, Karl J; Jung, Carina M; Alon Blakeney, G; Istok, Jonathan D; Hammett, Steven A

    2017-07-01

    Degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in laboratory columns following biostimulation and bioaugmentation was investigated using sediment and groundwater from a contaminated aquifer at a US Navy facility. No RDX degradation was observed following aerobic biostimulation with either fructose or lactate (both 0.1 mM) prior to bioaugmentation. Replicate columns were then bioaugmented with either Gordonia sp. KTR9, Pseudomonas fluorescens I-C (Ps I-C), or both strains. Under aerobic conditions (influent dissolved oxygen (DO) >6 mg/L), RDX was degraded following the addition of fructose, and to a lesser extent with lactate, in columns bioaugmented with KTR9. No degradation was observed in columns bioaugmented with only Ps I-C under aerobic conditions, consistent with the known anaerobic RDX degradation pathway for this strain. When influent DO was reduced to RDX degradation was observed in the KTR9-bioaugmented column, and some degradation was also observed in the Ps I-C-bioaugmented column. After DO levels were kept below 1 mg/L for more than a month, columns bioaugmented with KTR9 became unresponsive to fructose addition, while RDX degradation was still observed in the Ps I-C-bioaugmented columns. These results indicate that bioaugmentation with the aerobic RDX degrader KTR9 could be effective at sites where site geology or geochemistry allow higher DO levels to be maintained. Further, inclusion of strains capable of anoxic RDX degradation such as Ps I-C may facilitate bimodal RDX removal when DO levels decrease.

  5. Preparing for an Important Event: Demonstrating the Modern View of Classical Conditioning.

    Science.gov (United States)

    Kohn, Art; Kalat, James W.

    1992-01-01

    Explains a simple classroom demonstration of the modern view of classical conditioning. Suggests that the exercise is a useful demonstration of the view that classical conditioning helps prepare an organism for an upcoming event. Argues that the demonstration can show students that classical conditioning is broader and more intriguing than…

  6. Constraints of propylene glycol degradation at low temperatures and saturated flow conditions.

    Science.gov (United States)

    Lissner, Heidi; Wehrer, Markus; Reinicke, Martin; Horváth, Nikoletta; Totsche, Kai Uwe

    2015-02-01

    During snowmelt, the infiltration of large amounts of propylene glycol (PG), the major compound of many aircraft deicing fluids, affects redox processes and poses a contamination risk for the groundwater. To gain a better understanding about the degradation of PG and the associated biogeochemical processes under these conditions, we conducted saturated soil column experiments at 4 °C. During two successive PG pulses, we monitored the effect of the runway deicer formate (FO) and changing redox conditions on PG degradation. Furthermore, we applied first-order and simplified Monod kinetics to describe PG and FO transport. The transport of 50 mg l(-1) PG showed three stages of microbial degradation, which were defined as lag phase, aerobic phase, and anaerobic phase. During the second pulse, lag effects diminished due to the already accomplished microbial adaption, and the initial degradation rate of PG increased. Degradation of PG was most efficient during aerobic conditions (aerobic phase), while the subsequent drop of the redox potential down to -300 mV decreased the degradation rate (anaerobic phase). Formate addition decreased the overall degradation of PG by 50 and 15 % during the first and second pulse, illustrating the inhibitory effect of FO on PG degradation. The concurrent increase of Fe(III), organic carbon, and the turbidity in the column effluent after PG and FO application suggest the combined export of Fe adsorbed to fragments of detached biofilm. Neither the first-order nor the simplified Monod model was able to reconstruct the dynamic breakthrough of 50 mg l(-1) PG. The breakthrough of 1,000 mg l(-1), however, was described reasonably well with first-order kinetics. At low temperature and high water saturation, the application of first-order degradation kinetics seems therefore appropriate to describe the transport of high concentrations of PG.

  7. Optimum conditions for enzymatic degradation of some oilseed proteins

    Directory of Open Access Journals (Sweden)

    El-Zanaty, E. A.

    2002-09-01

    Full Text Available Soybean, sesame seed, and rice bran meal proteins were hydrolyzed with two enzymes, namely, papain and bromelain. Experiments were carried out to elucidate the optimum condition for each enzyme when acting on each substrate seperately. Results revealed that the highest relative activities for papain were achieved with E/S 0.06 , 0.29, 0.19 and pH 7.2, 7.0, 7.0 for soybean, sesame,and rice bran meal proteins, respectively. Optimum temperature for papain while hydrolysing the three substrates was 50 ºC. When using bromelain optimum E/S resulting in highest relative activities were 0.067, 0.058 and 0.21 for soybean, sesame,and rice bran meal protein, respectively. Optimum pH was 6.0 and optimum temperature was 45 ºC for bromelain when hydrolysing the protein of the three substrates. A numerical correlation of enzymatic behaviour for the different substrates was calculated.Proteínas de haba de soja, semilla de sésamo y harina de germen de arroz se hidrolizaron con dos enzimas, denominadas, papaina y bromelaina. Se han llevado a cabo experimentos para determinar las condiciones óptimas de cada enzima cuando actúan separadamente sobre cada sustrato. Los resultados mostraron que las mayores actividades relativas para la papaina se consiguieron con una E/S 0,06, 0,29, 0,19 y un pH 7.2, 7.0, 7.0 para las proteínas de haba de soja, sésamo y harina de germen de arroz, respectivamente. La temperatura óptima para la papaina durante la hidrólisis de los tres sustratos fue de 50 ºC. Cuando se usa bromelaina las relaciones E/S óptimas que proporcionaron mayor actividad relativa fueron 0.067, 0.058 y 0.21 para las proteínas de habas de soja, sésamo y harina de germen de arroz respectivamente. El pH óptimo fue 6.0 y la temperatura óptima 45 ºC para la bromelaina cuando se hidroliza la proteína de los tres sustratos. Con estos datos se hizo una correlación numérica del comportamiento enzimático para los diferentes sustratos.

  8. Modeling the kinetics of microbial degradation of deicing chemicals in porous media under flow conditions.

    Science.gov (United States)

    Wehrer, Markus; Jaesche, Philipp; Totsche, Kai Uwe

    2012-09-01

    A quantitative knowledge of the fate of deicing chemicals in the subsurface can be provided by joint analysis of lab experiments with numerical simulation models. In the present study, published experimental data of microbial degradation of the deicing chemical propylene glycol (PG) under flow conditions in soil columns were simulated inversely to receive the parameters of degradation. We evaluated different scenarios of an advection-dispersion model including different terms for degradation, such as zero order, first order and inclusion of a growing and decaying biomass for their ability to explain the data. The general break-through behavior of propylene glycol in soil columns can be simulated well using a coupled model of solute transport and degradation with growth and decay of biomass. The susceptibility of the model to non-unique solutions was investigated using systematical forward and inverse simulations. We found that the model tends to equifinal solutions under certain conditions.

  9. Rapid degradation of 2,4-dichlorophenoxyacetic acid facilitated by acetate under methanogenic condition.

    Science.gov (United States)

    Yang, Zhiman; Xu, Xiaohui; Dai, Meng; Wang, Lin; Shi, Xiaoshuang; Guo, Rongbo

    2017-05-01

    Acetate can be used as an electron donor to stimulate 2,4-dichlorophenoxyacetic acid (2,4-D), which has not been determined under methanogenic condition. This study applied high-throughput sequencing and methanogenic inhibition approaches to investigate the 2,4-D degradation process using the enrichments obtained from paddy soil. Acetate addition significantly promoted 2,4-D degradation, which was 5-fold higher than in the acetate-unsupplemented enrichments in terms of the 2,4-D degradation rate constant. Dechloromonas and Pseudomonas were the dominant 2,4-D degraders. Methanogenic inhibition experiments indicated that the 2,4-D degradation was independent of methanogenesis. It was proposed that the accelerated 2,4-D degradation in the acetate-supplemented enrichment involved an unusual interaction, where members of the acetate oxidizers primarily oxidized acetate and produced H2. H2 was utilized by the 2,4-D degraders to degrade 2,4-D, but also partially consumed by the hydrogenotrophic methanogens to produce methane. The findings presented here provide a new strategy for the remediation of 2,4-D-polluted soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions

    OpenAIRE

    Jia, Xiangqing; Qin, Chuan; Friedberger, Tobias; Guan, Zhibin; Huang, Zheng

    2016-01-01

    Polyethylene (PE) is the largest-volume synthetic polymer, and its chemical inertness makes its degradation by low-energy processes a challenging problem. We report a tandem catalytic cross alkane metathesis method for highly efficient degradation of polyethylenes under mild conditions. With the use of widely available, low-value, short alkanes (for example, petroleum ethers) as cross metathesis partners, different types of polyethylenes with various molecular weights undergo complete convers...

  11. Degradation of soil and hydrological conditions in the Peštan River Basin

    Directory of Open Access Journals (Sweden)

    Živanović Мilica

    2013-01-01

    Full Text Available In the Peštan River Basin, the right tributary of the Kolubara River, a complex degradation of natural conditions has been expressed over the decades. The exploitation of lignite in the Kolubara Coal Basin, which is in large part located in the territory of this basin, as well as accompanying activities related to it, are the dominant activities that lead to the degradation of soil and hydrological conditions. If other land use types are added to this, it can be concluded that the land cover in the studied territory suffered significant negative changes. The above mentioned activities have led to land loss and deterioration of its quality, and the regulation works due to dislocation of the Kolubara watercourse into the Peštan riverbed have caused numerous degradation of landscapes, reduced the basin area and shortened its watercourse, led to morphological changes of the river network and deterioration of the surface water quality. The aim of this paper is to perform a geospatial analysis of all areas in which the degradation of soil and hydrological conditions is present, in order to prevent their further degradation and proper management of these areas. [Projekat Ministarstva nauke Republike Srbije, br. 43007: The Research on Climate Change Influences on Environment: Influence Monitoring, Adaptation and Mitigation, subproject No. 9: Torrential Floods Frequency, Soil and Water Degradation as the Consequence of Global Changes

  12. Effects of environmental conditions on aerobic degradation of a commercial naphthenic acid.

    Science.gov (United States)

    Kinley, Ciera M; Gaspari, Daniel P; McQueen, Andrew D; Rodgers, John H; Castle, James W; Friesen, Vanessa; Haakensen, Monique

    2016-10-01

    Naphthenic acids (NAs) are problematic constituents in energy-derived waters, and aerobic degradation may provide a strategy for mitigating risks to aquatic organisms. The overall objective of this study was to determine the influence of concentrations of N (as ammonia) and P (as phosphate), and DO, as well as pH and temperatures on degradation of a commercial NA in bench-scale reactors. Commercial NAs provided replicable compounds necessary to compare influences of environmental conditions on degradation. NAs were quantified using high performance liquid chromatography. Microbial diversity and relative abundance were measured in treatments as explanatory parameters for potential effects of environmental conditions on microbial populations to support analytically measured NA degradation. Environmental conditions that positively influenced degradation rates of Fluka NAs included nutrients (C:N 10:1-500:1, C:P 100:1-5000:1), DO (4.76-8.43 mg L(-1)), pH (6-8), and temperature (5-25 °C). Approximately 50% removal of 61 ± 8 mg L(-1) was achieved in less than 2 d after NA introduction, achieving the method detection limit (5 mg L(-1)) by day 6 of the experiment in treatments with a C:N:P ratio of 100:10:1, DO > 8 mg L(-1), pH ∼8-9, and temperatures >23 °C. Microbial diversity was lowest in lower temperature treatments (6-16 °C), which may have resulted in observed slower NA degradation. Based on results from this study, when macro- and micronutrients were available, DO, pH, and temperature (within environmentally relevant ranges) influenced rates of aerobic degradation of Fluka NAs. This study could serve as a model for systematically evaluating environmental factors that influence NA degradation in field scenarios.

  13. Kinetics of p-aminoazobenzene degradation by Bacillus subtilis under denitrifying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zissi, U.S.; Kornaros, M.E.; Lyberatos, G.C.

    1999-05-01

    Bacillus subtilis is an organism capable of degrading an azo dye, such as p-aminoazobenzene (pAAB), under both aerobic and anoxic conditions. In both cases, pAAB is co-metabolized with a main carbon source and under anoxic conditions denitrification is observed. Kinetic experiments were carried out with a pure culture of B. subtilis and a mathematical model that accurately describes both biodegradation of pAAB under anoxic conditions and the denitrification process under both carbon- and nitrate- or nitrite-limited conditions is developed. Presence of pAAB in culture medium causes an inhibition of bacterial growth and of nitrite accumulation. Bacterial growth and pAAB degradation rates are found to be slower under anoxic conditions compared to the corresponding rates under aerobic conditions.

  14. Soil-Column Test on Aniline Degradation in Riverbank Filtration under Denitrification Conditions

    Institute of Scientific and Technical Information of China (English)

    Wu Yaoguo; Wang Hui; Zhang Wencun; Sun Weijian

    2005-01-01

    Drinking water is at risk from aniline pollution and thus aniline degradation and its mechanism have received much attention. In this paper, a soil column, including sediments and aquifer media, was collected from the Weihe riverbed and its bank, and used to research the characteristics of aniline degradation in the riverbank filtration process under denitrification conditions. The results indicate that all aniline could be degraded by the habituated indigenous microbes, and even mostly mineralized under denitrification conditions, but with a long lag phase. Some aniline degradation must involve deamination, while the majority undergoes covalent binding with humic substances to form complexes, and the complexes are easily degraded and even mineralized. During the degradation no intermediates were harmful to denitrifiers. Therefore, under denitrifaction conditions, aniline is degraded in RBF, and up to now aniline has not been monitored in the groundwater along the polluted river. During the 153 d testing process, the nitrate-nitrogen concentration was about 23.0 mg/L, and aniline concentrations were 40, 80 or 400 mg/L at 0-74 d, 75-105 d and 106-153 d respectively in infiltrating water. Indigenous microbes pass a lag period of 37 d, and grow on aniline as the source of carbon in the RBF under denitrification conditions. Aniline concentration in leachate was lower than the detected limits, so its removal rate was 100 %. Total organic carbon (TOC) removal rates were 97.99 %, 91.39 % and 75.30 % for 40, 80 and 400 mg/L aniline concentrations respectively, based on TOC monitored in infiltrating water and leachate.

  15. Screening a strain of Aspergillus niger and optimization of fermentation conditions for degradation of aflatoxin B₁.

    Science.gov (United States)

    Zhang, Wei; Xue, Beibei; Li, Mengmeng; Mu, Yang; Chen, Zhihui; Li, Jianping; Shan, Anshan

    2014-11-13

    Aflatoxin B₁, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B₁ after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B₁ after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B₁ degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B₁ was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B₁ degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B₁ degradation by the supernatant were examined. Results indicated that aflatoxin B₁ degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.

  16. Multi-technique approach for qualitative and quantitative characterization of furazidin degradation kinetics under alkaline conditions.

    Science.gov (United States)

    Bērziņš, Kārlis; Kons, Artis; Grante, Ilze; Dzabijeva, Diana; Nakurte, Ilva; Actiņš, Andris

    2016-09-10

    Degradation of drug furazidin was studied under different conditions of environmental pH (11-13) and temperature (30-60°C). The novel approach of hybrid hard- and soft-multivariate curve resolution-alternating least squares (HS-MCR-ALS) method was applied to UV-vis spectral data to determine a valid kinetic model and kinetic parameters of the degradation process. The system was found to be comprised of three main species and best characterized by two consecutive first-order reactions. Furazidin degradation rate was found to be highly dependent on the applied environmental conditions, showing more prominent differences between both degradation steps towards higher pH and temperature. Complimentary qualitative analysis of the degradation process was carried out using HPLC-DAD-TOF-MS. Based on the obtained chromatographic and mass spectrometric results, as well as additional computational analysis of the species (theoretical UV-vis spectra calculations utilizing TD-DFT methodology), the operating degradation mechanism was proposed to include formation of a 5-hydroxyfuran derivative, followed by complete hydrolysis of furazidin hydantoin ring.

  17. Multistate Degradation Mo del for Prognostics of Solder Joints Under Vibration Conditions

    Institute of Scientific and Technical Information of China (English)

    TANG Wei; JING Bo; HUANG Yifeng; SHENG Zengjin; JIAO Xiaoxuan

    2016-01-01

    This paper develops a multistate degra-dation structure of the solder joints which can be used under various vibration conditions based on nonhomoge-neous continuous-time hidden semi-Markov process. The parameters of the structure were estimated to illustrate the stochastic relationship between the degradation pro-cess and the monitoring indicator by using unsupervised learning methods. Random vibration tests on solder joints with different levels of power spectral density and fixed forms were conducted with a real time monitoring electri-cal resistance to examine the suitability of the model. It was experimentally verified that the multistate degrada-tion structure matches the experimental process reason-ably and accurately. Based on this multistate degradation model, the online prognostics of solder joint were analyzed and the results indicated that faults or failures can be de-tected timely, leading to appreciate maintenance actions scheduled to avoid catastrophic failures of electronics.

  18. Microstructure degradation of LSM-YSZ cathode in SOFCs operated at various conditions

    DEFF Research Database (Denmark)

    Liu, Yi-Lin; Thydén, Karl Tor Sune; Chen, Ming

    2012-01-01

    mechanisms have been identified. And it has been observed that different mechanisms dominate the degradation process under different test conditions. The severe cathode degradation at 750 °C operation with high current density is attributed to a loss of the cathode/electrolyte interface stability......Systematic microstructural analyses have been carried out on a series of technological SOFCs that went through long-term cell tests with various operating parameters including temperature, current load and time length under current. For the LSM-YSZ cathode, a number of microstructure degradation....... For the cells tested at 850 °C, the interface stability is maintained due to further sintering during cell operation. A cell test lasting for 2 years (17500 h) at 850 °C with a moderate current density (not greater than 1 A/cm2) has shown that the cathode microstructure is fairly robust to the degradation...

  19. [Degradation of polyhydroxyalkanoates and the composition of microbial destructors under natural conditions].

    Science.gov (United States)

    Volova, T G; Gladyshev, M I; Trusova, M Iu; Zhila, N O

    2006-01-01

    The degradation dynamics of polyhydroxyalkanoates of different composition has been studied in an eutrophic storage reservoir for two seasons. It has been shown that the biodegradation of polymers under natural conditions depends not only on their structure and physicochemical properties but also, to a great extent, on a complex of weather-climatic conditions affecting the state of the reservoir ecosystem. The molecular genetic analysis of 16S rRNA has revealed bacterial species (clones) probably involved in the degradation of polyhydroxyalkanoates in a model storage reservoir.

  20. Conditions for supplemental biogenic substrates to enhance activated sludge degradation of xenobiotic.

    Science.gov (United States)

    Nguyen, Lan Huong; Chong, Nyuk-Min

    2015-10-01

    The effects of biogenic presence on the degradation of xenobiotic organics by natural microbial populations have been reported as either advantageous or disadvantageous. The inconsistency of the reports implies there could be a turning point from disadvantageous to advantageous outcomes so that conditions may exist that could bring an optimum advantage. This study tested the supplementations of varying concentrations of sucrose and peptone, separately and combined, to acclimated activated sludge degradation of xenobiotic 2,4-D, while other operational and microbiological conditions were held constant. Our test results showed that biogenic may indeed enhance or slow down xenobiotic degradation rates. The highest enhancements exist at concentrations of 50 and 80 mg/L, respectively, for sucrose and peptone when supplemented separately, and 20 mg/L sucrose and 40 mg/L peptone combined. Conditions for advantageous biogenic supplementation were identified for activated sludge degradation of a xenobiotic; specifically, the highest degradation rate enhancements occurred when biogenic supplementation was approximately 0.5 to 0.7 the concentration of 2,4-D base on chemical oxygen demand (COD), which brought a biomass yield of approximately double that yielded by 2,4-D. Kinetics analyses provided clues for the possible causes of advantageous and disadvantageous effects due to biogenic supplementation.

  1. Degradation Kinetics of Atorvastatin under Stress Conditions and Chemical Analysis by HPLC

    Directory of Open Access Journals (Sweden)

    Romanélia Spessemille Valotto

    2013-01-01

    Full Text Available Atorvastatin is an antilipemic drug belonging to the statins class, whose reference drug is Pfizer’s Lipitor®. It is used to reduce the levels of lipoproteins rich in cholesterol and reduce the risk of coronary artery disease. It is well-known that calcium atorvastatin (ATV, C66H68CaF2N4O10•3H2O, presents polymorphism. The drug in question is commonly sought after by pharmaceutical industries that produce generic drugs, due to the fact that the drug has a high value price, it is consumed globally, and its patent expired in late 2010. Many questions concerning this drug’s pharmaceutical scope demonstrate its importance regarding stability studies and the identification of degradation products of drugs and pharmaceutical formulations. ATV has been found to degrade under acid and basic conditions, including a first order kinetic degradation under acid conditions, as compared to a zero order kinetic degradation under basic conditions, which tends to be less stable when studied within acid mediums. The rate constant (k for degradation in acid medium was 1.88 × 10−2 s−1 (first order, while for basic medium k = 2.35 × 10−4 mol L−1 s−1 (zero order, demonstrating a lower stability of the drug within acid mediums.

  2. Transference in view of a classical conditioning model.

    Science.gov (United States)

    Rabinovich, Merav; Kacen, Lea

    2012-01-01

    This article presents a qualitative metasynthetic study, addressing 33 transference case studies, that investigates the interrelationship of the transference concept from psychoanalysis and cognitive-behavioral concepts in an attempt to construct a theoretical platform for clinical integration. Relationship between categories analysis was used to compare Luborsky's (1998) transference components (wish, response from other, and response of self) and cognitive-behavioral ones. Results showed reciprocal relations between transference and classical conditioning. Furthermore, explicit occurrences of distorted thinking due to overgeneralization were found in more than 90% of the cases. A conceptual model describes transference as a conditioned response activated by thematic conditioning, a particular case of classical conditioning that repeatedly pairs a given interpersonal situation with internal thematic stimuli, thus shaping the person's narrative. Theoretical and practical implications are discussed as well.

  3. [Degradation dynamics of POPs atrazine in soils under long-term located fertilization conditions].

    Science.gov (United States)

    Wang, Jun; Zhu, Lu-sheng; Xie, Hui; Song, Yan; Sun, Rui-lian; Zhang, Fu-dao

    2007-12-01

    To evaluate the difference of POPs atrazine degradation dynamics in soils under different fertilization conditions, we set up an analysis method of the atrazine residue in soils and studied residue dynamics of atrazine in soils under a long-term located fertilization conditions. After extracted by surging with acetone, liquid-liquid partition and eluted through florisil, the residue of atrazine in soils was detected by gas chromatogram with 63Ni-ECD. The minimum detectable quantity of atrazine is 6.4 x 10(-12) g and the minimum detectable concentration is 6.4 x 10(-9) g x kg(-1) in the soil. The spiked recoveries of atrazine with the three concentration of 0.11, 1.1, 11.0 mg x kg(-1) in soils are 91.41% +/- 4.36%, 93.58% +/- 4.54%, 90.35% +/- 3.59%, according with the request of pesticide residue analysis. The degradation of atrazine in soil under a long-term located fertilization conditions was studied. The results show the degradation of atrazine follows stair dynamic equation, and the degradation half-life of atrazine in soils fertilized with CK, NPK, NPK + M, NPK + S are 20.6, 23.0, 28.5, 33.2 d, respectively. Subjected to analysis of LSR, NPK and organic fertilizers are obviously propitious to the degradation of atrazine. The separate regression and stepwise regression analysis prove the degradation half-life of atrazine in soils is well related with the content of alkaline nitrogen, organic matter and total nitrogen, and the coefficients are 0.9983, 0.9826 and 0.9521, respectively. Maybe the reason is that these soil nutrient substance offers enough the element carbon and nitrogen for action of microbe, and the higher action of microbe quickens the degradation of atrazine in soils.

  4. Stability of barakol under hydrolytic stress conditions and its major degradation product.

    Science.gov (United States)

    Chantong, Boonrat; Wongtongtair, Supim; Nusuetrong, Punnee; Sotanaphun, Uthai; Chaichantipyuth, Chaiyo; Meksuriyen, Duangdeun

    2009-03-01

    The aim of the present study was to investigate the stability of barakol, an anxiolytic constituent extracted from leaves of Senna siamea (Lam.) Irwin & Barneby (syn. Cassia siamea Lam.), under the International Conference on Harmonisation suggested conditions using HPLC with photodiode array detection. Extensive degradation of barakol was found to occur under alkaline conditions through base-catalyzed hydrolysis. Mild degradation of barakol was observed under thermal and oxidative stress while it was stable under acidic conditions. The reaction rate constants (Kobs) of barakol degradation under alkaline conditions at pHs 12 and 13 were 3.0x10(-5) and 9.6x10(-3) min(-1), respectively. The activation energy according to the Arrhenius plot was calculated to be 26.9+/-3.3 kcal/mol at pH 13 and temperatures between 12 and 51 degrees C. The major degradation product of barakol under both alkaline and thermal stress conditions was characterized by LC-MS and NMR as cassiachromone.

  5. Degradation of the pharmaceuticals diclofenac and sulfamethoxazole and their transformation products under controlled environmental conditions.

    Science.gov (United States)

    Poirier-Larabie, S; Segura, P A; Gagnon, C

    2016-07-01

    Contamination of the aquatic environment by pharmaceuticals via urban effluents is well known. Several classes of drugs have been identified in waterways surrounding these effluents in the last 15years. To better understand the fate of pharmaceuticals in ecosystems, degradation processes need to be investigated and transformation products must be identified. Thus, this study presents the first comparative study between three different natural environmental conditions: photolysis and biodegradation in aerobic and anaerobic conditions both in the dark of diclofenac and sulfamethoxazole, two common drugs present in significant amounts in impacted surface waters. Results indicated that degradation kinetics differed depending on the process and the type of drug and the observed transformation products also differed among these exposure conditions. Diclofenac was nearly degraded by photolysis after 4days, while its concentration only decreased by 42% after 57days of exposure to bacteria in aerobic media and barely 1% in anaerobic media. For sulfamethoxazole, 84% of the initial concentration was still present after 11days of exposure to light, while biodegradation decreased its concentration by 33% after 58days of exposure under aerobic conditions and 5% after 70days of anaerobic exposure. In addition, several transformation products were observed and persisted over time while others degraded in turn. For diclofenac, chlorine atoms were lost primarily in the photolysis, while a redox reaction was promoted by biodegradation under aerobic conditions. For sulfamethoxazole, isomerization was favored by photolysis while a redox reaction was also favored by the biodegradation under aerobic conditions. To summarize this study points out the occurrence of different transformation products under variable degradation conditions and demonstrates that specific functional groups are involved in the tested natural attenuation processes. Given the complexity of environmental samples

  6. Modelling Visual Change Detection and Identification under Free Viewing Conditions.

    Science.gov (United States)

    McAnally, Ken; Martin, Russell

    2016-01-01

    We examined whether the abilities of observers to perform an analogue of a real-world monitoring task involving detection and identification of changes to items in a visual display could be explained better by models based on signal detection theory (SDT) or high threshold theory (HTT). Our study differed from most previous studies in that observers were allowed to inspect the initial display for 3s, simulating the long inspection times typical of natural viewing, and their eye movements were not constrained. For the majority of observers, combined change detection and identification performance was best modelled by a SDT-based process that assumed that memory resources were distributed across all eight items in our displays. Some observers required a parameter to allow for sometimes making random guesses at the identities of changes they had missed. However, the performance of a small proportion of observers was best explained by a HTT-based model that allowed for lapses of attention.

  7. LabVIEW based Condition Monitoring of Induction Machines

    Directory of Open Access Journals (Sweden)

    K.Vinoth Kumar

    2012-04-01

    Full Text Available This paper focuses on experimental results to prove that motor current signature analysis (MCSA can diagnose shorted turns in low voltage stator windings of 3-phase induction motors using LabVIEW. The diagnostic strategy is presented and variables that influence the diagnosis are discussed. Current spectra from motors with short-circuited turns (with and without short circuit current limiting resistors are presented and fully analyzed. Results from motors tested to failure are reported. The results in this paper were from industrial motors of different pole numbers with concentric and lap wound winding designs. Since stator failures account for a high percentage of failures the results are particularly relevant to industry.

  8. High-power UV-LED degradation: Continuous and cycled working condition influence

    Science.gov (United States)

    Arques-Orobon, F. J.; Nuñez, N.; Vazquez, M.; Segura-Antunez, C.; González-Posadas, V.

    2015-09-01

    High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3 W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal and optical HP UV-LED measurements has been performed. Static thermal and stress simulation analysis with the finite element method (FEM) identifies the causes of package degradation. Accelerated life test results prove that HP UV-LEDs working in cycled condition have a better performance than those working in continuous condition.

  9. Modelling Visual Change Detection and Identification under Free Viewing Conditions.

    Directory of Open Access Journals (Sweden)

    Ken McAnally

    Full Text Available We examined whether the abilities of observers to perform an analogue of a real-world monitoring task involving detection and identification of changes to items in a visual display could be explained better by models based on signal detection theory (SDT or high threshold theory (HTT. Our study differed from most previous studies in that observers were allowed to inspect the initial display for 3s, simulating the long inspection times typical of natural viewing, and their eye movements were not constrained. For the majority of observers, combined change detection and identification performance was best modelled by a SDT-based process that assumed that memory resources were distributed across all eight items in our displays. Some observers required a parameter to allow for sometimes making random guesses at the identities of changes they had missed. However, the performance of a small proportion of observers was best explained by a HTT-based model that allowed for lapses of attention.

  10. Eye tracking under dichoptic viewing conditions: a practical solution.

    Science.gov (United States)

    Brascamp, Jan W; Naber, Marnix

    2017-08-01

    In several research contexts it is important to obtain eye-tracking measures while presenting visual stimuli independently to each of the two eyes (dichoptic stimulation). However, the hardware that allows dichoptic viewing, such as mirrors, often interferes with high-quality eye tracking, especially when using a video-based eye tracker. Here we detail an approach to combining mirror-based dichoptic stimulation with video-based eye tracking, centered on the fact that some mirrors, although they reflect visible light, are selectively transparent to the infrared wavelength range in which eye trackers record their signal. Although the method we propose is straightforward, affordable (on the order of US$1,000) and easy to implement, for many purposes it makes for an improvement over existing methods, which tend to require specialized equipment and often compromise on the quality of the visual stimulus and/or the eye tracking signal. The proposed method is compatible with standard display screens and eye trackers, and poses no additional limitations on the quality or nature of the stimulus presented or the data obtained. We include an evaluation of the quality of eye tracking data obtained using our method, and a practical guide to building a specific version of the setup used in our laboratories.

  11. Promotive effect of pyridine on indole degradation by activated sludge under anoxic conditions

    Institute of Scientific and Technical Information of China (English)

    LI Yongmei; LI Wenshu; GU Guowei

    2007-01-01

    Batch experiments were carried out to investigate the promotive effect ofpyridine on indole degradation under denitrifying conditions.The seed sludge was obtained from a local coal-coking wastewater treatment facility and was acclimated in the laboratory.Indole and pyridine were supplemented to the synthetic wastewater at different ratios.The optimum ratio of chemical oxygen demand (COD) to nitrate (C/N) was 8.4-8.9 for both denitrification and indole and pyridine degradation.At a temperature of 28℃ and pH of 7.0-7.5,the nitrate reductase activity (NRA) was in the best state.The addition of pyridine could promote NRA and the degradation of indole.When the initial concentration of indole was 150 mg/L,the concentration ratio of indole to pyridine was in the range of 1-10.Under optimum C/N conditions,the degradation of indole could be described with pseudo-zero-order kinetics.There was no accumulation of nitrite during the reaction.When the concentration ratio of pyridine to indole was less than 0.25 with an increase in the pyridine proportion,there were more significant augment rates for NRA and the degradation of indole than the situation when the concentration ratio was more than 0.25.

  12. Cylindrospermopsin degradation in sediments--the role of temperature, redox conditions, and dissolved organic carbon.

    Science.gov (United States)

    Klitzke, Sondra; Fastner, Jutta

    2012-04-01

    One possible consequence of increasing water temperatures due to global warming in middle Europe is the proliferation of cylindrospermopsin-producing species from warmer regions. This may lead to more frequent and increased cylindrospermopsin (CYN) concentrations in surface waters. Hence, efficient elimination of CYN is important where contaminated surface waters are used as a resource for drinking water production via sediment passage. Sediments are often characterized by a lack of oxygen and low temperature (i.e. approx. 10 °C). The presence of dissolved organic carbon (DOC) is not only known to enhance but also to retard contaminant degradation by influencing the extent of lag phases. So far CYN degradation has only been investigated under oxic conditions and at room temperature. Therefore, the aim of our experiments was to understand CYN degradation, focusing on the effects of i) anoxic conditions, ii) low temperature (i.e. 10 °C) in comparison to room temperature (23±4 °C) and iii) DOC on lag phases. We used two natural sandy sediments (virgin and preconditioned) and surface water to conduct closed-loop column experiments. Anoxic conditions either inhibited CYN degradation completely or retarded CYN breakdown in comparison to oxic conditions (T(1/2) (oxic)=2.4 days, T(1/2) (anoxic)=23.6 days). A decrease in temperature from 20 °C to 10 °C slowed down degradation rates by a factor of 10. The presence of DOC shortened lag phases in virgin sediments at room temperature but induced a lag phase in preconditioned sediments at 10 °C, indicating potential substrate competition. These results show that information on physico-chemical conditions in sediments is crucial to assess the risk of CYN breakthrough. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Degradation and performance evaluation of PV module in desert climate conditions with estimate uncertainty in measuring

    Directory of Open Access Journals (Sweden)

    Fezzani Amor

    2017-01-01

    Full Text Available The performance of photovoltaic (PV module is affected by outdoor conditions. Outdoor testing consists installing a module, and collecting electrical performance data and climatic data over a certain period of time. It can also include the study of long-term performance under real work conditions. Tests are operated in URAER located in desert region of Ghardaïa (Algeria characterized by high irradiation and temperature levels. The degradation of PV module with temperature and time exposure to sunlight contributes significantly to the final output from the module, as the output reduces each year. This paper presents a comparative study of different methods to evaluate the degradation of PV module after a long term exposure of more than 12 years in desert region and calculates uncertainties in measuring. Firstly, this evaluation uses three methods: Visual inspection, data given by Solmetric PVA-600 Analyzer translated at Standard Test Condition (STC and based on the investigation results of the translation equations as ICE 60891. Secondly, the degradation rates calculated for all methods. Finally, a comparison between a degradation rates given by Solmetric PVA-600 analyzer, calculated by simulation model and calculated by two methods (ICE 60891 procedures 1, 2. We achieved a detailed uncertainty study in order to improve the procedure and measurement instrument.

  14. Chlorophyll b degradation by chlorophyll b reductase under high-light conditions.

    Science.gov (United States)

    Sato, Rei; Ito, Hisashi; Tanaka, Ayumi

    2015-12-01

    The light-harvesting chlorophyll a/b binding protein complex of photosystem II (LHCII) is the main antenna complex of photosystem II (PSII). Plants change their LHCII content depending on the light environment. Under high-light conditions, the content of LHCII should decrease because over-excitation damages the photosystem. Chlorophyll b is indispensable for accumulating LHCII, and chlorophyll b degradation induces LHCII degradation. Chlorophyll b degradation is initiated by chlorophyll b reductase (CBR). In land plants, NON-YELLOW COLORING 1 (NYC1) and NYC1-Like (NOL) are isozymes of CBR. We analyzed these mutants to determine their functions under high-light conditions. During high-light treatment, the chlorophyll a/b ratio was stable in the wild-type (WT) and nol plants, and the LHCII content decreased in WT plants. The chlorophyll a/b ratio decreased in the nyc1 and nyc1/nol plants, and a substantial degree of LHCII was retained in nyc1/nol plants after the high-light treatment. These results demonstrate that NYC1 degrades the chlorophyll b on LHCII under high-light conditions, thus decreasing the LHCII content. After the high-light treatment, the maximum quantum efficiency of the PSII photochemistry was lower in nyc1 and nyc1/nol plants than in WT and nol plants. A larger light-harvesting system would damage PSII in nyc1 and nyc1/nol plants. The fluorescence spectroscopy of the leaves indicated that photosystem I was also damaged by the excess LHCII in nyc1/nol plants. These observations suggest that chlorophyll b degradation by NYC1 is the initial reaction for the optimization of the light-harvesting capacity under high-light conditions.

  15. Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions.

    Science.gov (United States)

    Jia, Xiangqing; Qin, Chuan; Friedberger, Tobias; Guan, Zhibin; Huang, Zheng

    2016-06-01

    Polyethylene (PE) is the largest-volume synthetic polymer, and its chemical inertness makes its degradation by low-energy processes a challenging problem. We report a tandem catalytic cross alkane metathesis method for highly efficient degradation of polyethylenes under mild conditions. With the use of widely available, low-value, short alkanes (for example, petroleum ethers) as cross metathesis partners, different types of polyethylenes with various molecular weights undergo complete conversion into useful liquid fuels and waxes. This method shows excellent selectivity for linear alkane formation, and the degradation product distribution (liquid fuels versus waxes) can be controlled by the catalyst structure and reaction time. In addition, the catalysts are compatible with various polyolefin additives; therefore, common plastic wastes, such as postconsumer polyethylene bottles, bags, and films could be converted into valuable chemical feedstocks without any pretreatment.

  16. Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions

    Science.gov (United States)

    Jia, Xiangqing; Qin, Chuan; Friedberger, Tobias; Guan, Zhibin; Huang, Zheng

    2016-01-01

    Polyethylene (PE) is the largest-volume synthetic polymer, and its chemical inertness makes its degradation by low-energy processes a challenging problem. We report a tandem catalytic cross alkane metathesis method for highly efficient degradation of polyethylenes under mild conditions. With the use of widely available, low-value, short alkanes (for example, petroleum ethers) as cross metathesis partners, different types of polyethylenes with various molecular weights undergo complete conversion into useful liquid fuels and waxes. This method shows excellent selectivity for linear alkane formation, and the degradation product distribution (liquid fuels versus waxes) can be controlled by the catalyst structure and reaction time. In addition, the catalysts are compatible with various polyolefin additives; therefore, common plastic wastes, such as postconsumer polyethylene bottles, bags, and films could be converted into valuable chemical feedstocks without any pretreatment. PMID:27386559

  17. Atrazine degradation by fungal co-culture enzyme extracts under different soil conditions.

    Science.gov (United States)

    Chan-Cupul, Wilberth; Heredia-Abarca, Gabriela; Rodríguez-Vázquez, Refugio

    2016-01-01

    This investigation was undertaken to determine the atrazine degradation by fungal enzyme extracts (FEEs) in a clay-loam soil microcosm contaminated at field application rate (5 μg g(-1)) and to study the influence of different soil microcosm conditions, including the effect of soil sterilization, water holding capacity, soil pH and type of FEEs used in atrazine degradation through a 2(4) factorial experimental design. The Trametes maxima-Paecilomyces carneus co-culture extract contained more laccase activity and hydrogen peroxide (H2O2) content (laccase = 18956.0 U mg protein(-1), H2O2 = 6.2 mg L(-1)) than the T. maxima monoculture extract (laccase = 12866.7 U mg protein(-1), H2O2 = 4.0 mg L(-1)). Both extracts were able to degrade atrazine at 100%; however, the T. maxima monoculture extract (0.32 h) achieved a lower half-degradation time than its co-culture with P. carneus (1.2 h). The FEE type (p = 0.03) and soil pH (p = 0.01) significantly affected atrazine degradation. The best degradation rate was achieved by the T. maxima monoculture extract in an acid soil (pH = 4.86). This study demonstrated that both the monoculture extracts of the native strain T. maxima and its co-culture with P. carneus can efficiently and quickly degrade atrazine in clay-loam soils.

  18. Enantioselective degradation of (2RS,3RS)-paclobutrazol in peach and mandarin under field conditions.

    Science.gov (United States)

    Wang, Xiangyun; Qi, Peipei; Yang, Guiling; Wang, Xinquan; Zhang, Hu; Xu, Hao; Wang, Zhiwei; Wang, Qiang

    2014-08-01

    In this study we investigated the enantioselective degradation of (2RS,3RS)-paclobutrazol in peach and mandarin fruits under field conditions after foliar treatment at 500 mg active ingredient/L using a Lux Cellulose-1 chiral column on a reverse-phase liquid chromatography-tandem mass spectrometry system. Degradations of paclobutrazol in both fruits followed first-order kinetics, with half-lives of about 9 days. Initial deposits were 1.63 mg/kg on peach and 1.99 mg/kg on mandarin; terminal concentrations were lower than 0.05 mg/kg, which was acceptable in most cases. As anticipated, paclobutrazol levels in peels of mature mandarin were about 6.3 times higher than in pulp, indicating the potential risk of peel consumption. We also observed that paclobutrazol degradation in mature mandarin was relatively slow, indicating it might not be efficient enough to hold mandarin fruits on trees for lowering paclobutrazol concentrations. Significant enantioselectivity was observed: the (2R,3R)-enantiomer was preferentially degraded in mandarin (whole fruit, peels, and pulp) but enriched in peach. Because of its more rapid degradation in mandarin and the lower levels observed in pulp compared with peels, potential endocrine-related side effects due to the (2R,3R)-enantiomer pose less of a risk in mandarin than in peach.

  19. Bacterial assisted degradation of chlorpyrifos: The key role of environmental conditions, trace metals and organic solvents.

    Science.gov (United States)

    Khalid, Saira; Hashmi, Imran; Khan, Sher Jamal

    2016-03-01

    Wastewater from pesticide industries, agricultural or surface runoff containing pesticides and their residues has adverse environmental impacts. Present study demonstrates effect of petrochemicals and trace metals on chlorpyrifos (CP) biotransformation often released in wastewater of agrochemical industry. Biodegradation was investigated using bacterial strain Pseudomonas kilonensis SRK1 isolated from wastewater spiked with CP. Optimal environmental conditions for CP removal were CFU (306 × 10(6)), pH (8); initial CP concentration (150 mg/L) and glucose as additional carbon source. Among various organic solvents (petrochemicals) used in this study toluene has stimulatory effect on CP degradation process using SRK1, contrary to this benzene and phenol negatively inhibited degradation process. Application of metal ions (Cu (II), Fe (II) Zn (II) at low concentration (1 mg/L) took part in biochemical reaction and positively stimulated CP degradation process. Metal ions at high concentrations have inhibitory effect on degradation process. A first order growth model was shown to fit the data. It could be concluded that both type and concentration of metal ions and petrochemicals can affect CP degradation process.

  20. Enzymatic formulation capable of degrading scrapie prion under mild digestion conditions.

    Directory of Open Access Journals (Sweden)

    Emeka A Okoroma

    Full Text Available The prion agent is notoriously resistant to common proteases and conventional sterilisation procedures. The current methods known to destroy prion infectivity such as incineration, alkaline and thermal hydrolysis are harsh, destructive, environmentally polluting and potentially hazardous, thus limit their applications for decontamination of delicate medical and laboratory devices, remediation of prion contaminated environment and for processing animal by-products including specified risk materials and carcases. Therefore, an environmentally friendly, non-destructive enzymatic degradation approach is highly desirable. A feather-degrading Bacillus licheniformis N22 keratinase has been isolated which degraded scrapie prion to undetectable level of PrP(Sc signals as determined by Western Blot analysis. Prion infectivity was verified by ex vivo cell-based assay. An enzymatic formulation combining N22 keratinase and biosurfactant derived from Pseudomonas aeruginosa degraded PrP(Sc at 65 °C in 10 min to undetectable level -. A time-course degradation analysis carried out at 50 °C over 2 h revealed the progressive attenuation of PrP(Sc intensity. Test of residual infectivity by standard cell culture assay confirmed that the enzymatic formulation reduced PrP(Sc infectivity to undetectable levels as compared to cells challenged with untreated standard scrapie sheep prion (SSBP/1 (p-value = 0.008 at 95% confidence interval. This novel enzymatic formulation has significant potential application for prion decontamination in various environmentally friendly systems under mild treatment conditions.

  1. Aerobic versus Anaerobic Microbial Degradation of Clothianidin under Simulated California Rice Field Conditions.

    Science.gov (United States)

    Mulligan, Rebecca A; Tomco, Patrick L; Howard, Megan W; Schempp, Tabitha T; Stewart, Davis J; Stacey, Phillip M; Ball, David B; Tjeerdema, Ronald S

    2016-09-28

    Microbial degradation of clothianidin was characterized under aerobic and anaerobic California rice field conditions. Rate constants (k) and half-lives (DT50) were determined for aerobic and anaerobic microcosms, and an enrichment experiment was performed at various nutrient conditions and pesticide concentrations. Temperature effects on anaerobic degradation rates were determined at 22 ± 2 and 35 ± 2 °C. Microbial growth was assessed in the presence of various pesticide concentrations, and distinct colonies were isolated and identified. Slow aerobic degradation was observed, but anaerobic degradation occurred rapidly at both 25 and 35 °C. Transformation rates and DT50 values in flooded soil at 35 ± 2 °C (k = -7.16 × 10(-2) ± 3.08 × 10(-3) day(-1), DT50 = 9.7 days) were significantly faster than in 25 ± 2 °C microcosms (k= -2.45 × 10(-2) ± 1.59 × 10(-3) day(-1), DT50 = 28.3 days). At the field scale, biodegradation of clothianidin will vary with extent of oxygenation.

  2. Microbial degradation of nonylphenol and other alkylphenols--our evolving view.

    Science.gov (United States)

    Corvini, P F X; Schäffer, A; Schlosser, D

    2006-09-01

    Because the endocrine disrupting effects of nonylphenol (NP) and octylphenol became evident, the degradation of long-chain alkylphenols (AP) by microorganisms was intensively studied. Most NP-degrading bacteria belong to the sphingomonads and closely related genera, while NP metabolism is not restricted to defined fungal taxa. Growth on NP and its mineralization was demonstrated for bacterial isolates, whereas ultimate degradation by fungi still remains unclear. While both bacterial and fungal degradation of short-chain AP, such as cresols, and the bacterial degradation of long-chain branched AP involves aromatic ring hydroxylation, alkyl chain oxidation and the formation of phenolic polymers seem to be preferential elimination pathways of long-chain branched AP in fungi, whereby both intracellular and extracellular oxidative enzymes may be involved. The degradation of NP by sphingomonads does not proceed via the common degradation mechanisms reported for short-chain AP, rather, via an unusual ipso-substitution mechanism. This fact underlies the peculiarity of long-chain AP such as NP isomers, which possess highly branched alkyl groups mostly containing a quaternary alpha-carbon. In addition to physicochemical parameters influencing degradation rates, this structural characteristic confers to branched isomers of NP a biodegradability different to that of the widely used linear isomer of NP. Potential biotechnological applications for the removal of AP from contaminated media and the difficulties of analysis and application inherent to the hydrophobic NP, in particular, are also discussed. The combination of bacteria and fungi, attacking NP at both the phenolic and alkylic moiety, represents a promising perspective.

  3. Degradation of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl) urea by nanoscale zerovalent iron under aerobic and anaerobic conditions.

    Science.gov (United States)

    Lin, Haiying; Hou, Shaogang; Xie, Guohong; Yao, Ziwei; Zhou, Qingxiang

    2012-01-01

    The goal of present study was to investigate the applicability of nanoscale zerovalent iron (NZVI) on the degradation of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl) urea (CCU) under aerobic and anaerobic conditions, respectively. The experimental results showed that NZVI could effectively degrade CCU, but the removal efficiencies were different under these two different conditions. The best removal efficiencies for CCU were 90.2 and 75.8% under aerobic and anaerobic conditions, respectively. The highly oxidative hydroxyl radicals and reductively hydrogen would account for the rapid degradation of CCU under aerobic and anaerobic conditions, respectively. The experimental results also showed that surfactant Tween 20 significantly inhibited the degradation of CCU under aerobic conditions. However it markedly enhanced the degradation of CCU under anaerobic condition.

  4. Degradation kinetics of a potent antifouling agent, butenolide, under various environmental conditions

    KAUST Repository

    Chen, Lianguo

    2015-01-01

    © 2014 Elsevier Ltd. Here, we investigated the degradation kinetics of butenolide, a promising antifouling compound, under various environmental conditions. The active ingredient of the commercial antifoulant SeaNine 211, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), was used as positive control. The results showed that the degradation rate increased with increasing temperature. Half-lives of butenolide at 4. °C, 25. °C and 40. °C were. >64. d, 30.5. d and 3.9. d, respectively. Similar half-lives were recorded for DCOIT: >64. d at 4. °C, 27.9. d at 25. °C and 4.5. d at 40. °C. Exposure to sunlight accelerated the degradation of both butenolide and DCOIT. The photolysis half-lives of butenolide and DCOIT were 5.7. d and 6.8. d, respectively, compared with 9.7. d and 14.4. d for the dark control. Biodegradation led to the fastest rate of butenolide removal from natural seawater, with a half-life of 0.5. d, while no obvious degradation was observed for DCOIT after incubation for 4. d. The biodegradative ability of natural seawater for butenolide was attributed mainly to marine bacteria. During the degradation of butenolide and DCOIT, a gradual decrease in antifouling activity was observed, as indicated by the increased settlement percentage of cypris larvae from barnacle Balanus amphitrite. Besides, increased cell growth of marine diatom Skeletonema costatum demonstrated that the toxicity of seawater decreased gradually without generation of more toxic by-products. Overall, rapid degradation of butenolide in natural seawater supported its claim as a promising candidate for commercial antifouling industry.

  5. Degradation kinetics of a potent antifouling agent, butenolide, under various environmental conditions.

    Science.gov (United States)

    Chen, Lianguo; Xu, Ying; Wang, Wenxiong; Qian, Pei-Yuan

    2015-01-01

    Here, we investigated the degradation kinetics of butenolide, a promising antifouling compound, under various environmental conditions. The active ingredient of the commercial antifoulant SeaNine 211, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), was used as positive control. The results showed that the degradation rate increased with increasing temperature. Half-lives of butenolide at 4 °C, 25 °C and 40 °C were>64 d, 30.5 d and 3.9 d, respectively. Similar half-lives were recorded for DCOIT: >64 d at 4 °C, 27.9 d at 25 °C and 4.5d at 40 °C. Exposure to sunlight accelerated the degradation of both butenolide and DCOIT. The photolysis half-lives of butenolide and DCOIT were 5.7 d and 6.8 d, respectively, compared with 9.7 d and 14.4 d for the dark control. Biodegradation led to the fastest rate of butenolide removal from natural seawater, with a half-life of 0.5 d, while no obvious degradation was observed for DCOIT after incubation for 4 d. The biodegradative ability of natural seawater for butenolide was attributed mainly to marine bacteria. During the degradation of butenolide and DCOIT, a gradual decrease in antifouling activity was observed, as indicated by the increased settlement percentage of cypris larvae from barnacle Balanus amphitrite. Besides, increased cell growth of marine diatom Skeletonema costatum demonstrated that the toxicity of seawater decreased gradually without generation of more toxic by-products. Overall, rapid degradation of butenolide in natural seawater supported its claim as a promising candidate for commercial antifouling industry.

  6. A dimethacrylate cross-linker cleavable under thermolysis or alkaline hydrolysis conditions: synthesis, polymerization, and degradation.

    Science.gov (United States)

    Elladiou, Marios; Patrickios, Costas S

    2016-02-21

    We develop a new platform based on 2,6-pyridinediethanol diesters for introducing polymer degradability under thermolysis or alkaline hydrolysis conditions, with the latter being rare in polymers. Such labile diesters can be cross-linkers, bifunctional initiators and inimers. We demonstrate the power of this platform through the synthesis of the 2,6-pyridinediethanol dimethacrylate cross-linker, its controlled (co)polymerization, and the thermal and hydrolytic cleavage of its (co)polymers.

  7. Tidal Flushing Restores the Physiological Condition of Fish Residing in Degraded Salt Marshes

    OpenAIRE

    Dibble, Kimberly L.; Meyerson, Laura A.

    2012-01-01

    Roads, bridges, and dikes constructed across salt marshes can restrict tidal flow, degrade habitat quality for nekton, and facilitate invasion by non-native plants including Phragmites australis. Introduced P. australis contributes to marsh accretion and eliminates marsh surface pools thereby adversely affecting fish by reducing access to intertidal habitats essential for feeding, reproduction, and refuge. Our study assessed the condition of resident fish populations (Fundulus heteroclitus) a...

  8. Degradation studies of fenazaquin in soil under field and laboratory conditions.

    Science.gov (United States)

    Duhan, Anil; Kumari, Beena

    2011-08-01

    Degradation of fenazaquin in sandy loam soil was investigated under field and laboratory conditions. Fenazaquin (Magister 10EC) was applied @ 125 and 250 g a.i./ha in field and in pot under field capacity moisture in laboratory. Samples drawn periodically were analyzed on GC-NPD. The residues of fenazaquin in both the doses and conditions dissipated almost 90% in 90 days. Half-life period were 32.04 and 31.35 days at two doses, respectively at field conditions and 30.10 and 28.94 days at laboratory conditions. Dissipation was approximated to first order kinetics in both conditions having correlation coefficient ranging from -0.9848 to -0.9914.

  9. Degradation of municipal solid waste in simulated landfill bioreactors under aerobic conditions.

    Science.gov (United States)

    Slezak, Radoslaw; Krzystek, Liliana; Ledakowicz, Stanislaw

    2015-09-01

    In this study the municipal solid waste degradation processes in simulated landfill bioreactors under aerobic and anaerobic conditions is investigated. The effect of waste aeration on the dynamics of the aerobic degradation processes in lysimeters as well as during anaerobic processes after completion of aeration is presented. The results are compared with the anaerobic degradation process to determine the stabilization stage of waste in both experimental modes. The experiments in aerobic lysimeters were carried out at small aeration rate (4.41⋅10(-3)lmin(-1)kg(-1)) and for two recirculation rates (24.9 and 1.58lm(-3)d(-1)). The change of leachate and formed gases composition showed that the application of even a small aeration rate favored the degradation of organic matter. The amount of CO2 and CH4 released from anaerobic lysimeter was about 5 times lower than that from the aerobic lysimeters. Better stabilization of the waste was obtained in the aerobic lysimeter with small recirculation, from which the amount of CO2 produced was larger by about 19% in comparison with that from the aerobic lysimeter with large leachate recirculation.

  10. Characterization of degradation products of amorphous and polymorphic forms of clopidogrel bisulphate under solid state stress conditions

    DEFF Research Database (Denmark)

    Raijada, Dhara K; Prasad, Bhagwat; Paudel, Amrit

    2010-01-01

    The present study deals with the stress degradation studies on amorphous and polymorphic forms of clopidogrel bisulphate. The objective was to characterize the degradation products and postulate mechanism of decomposition of the drug under solid state stress conditions. For that, amorphous form...... degradation products were observed under various stress conditions. The structures of all of them were elucidated using LC-MS/TOF and LC-MS(n) studies. While one matched the known hydrolytic decomposition product of the drug in solution, seven others were new. The postulated degradation pathway and mechanism...

  11. 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.

  12. Green synthesized conditions impacting on the reactivity of Fe NPs for the degradation of malachite green

    Science.gov (United States)

    Huang, Lanlan; Luo, Fang; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

    2015-02-01

    This study investigates green tea extract synthesized conditions impacting on the reactivity of iron nanoparticles (Fe NPs) used for the degradation of malachite green (MG), including the volume ratio of Fe2+ and tea extract, the solution pH and temperature. Results indicated that the reactivity of Fe NPs increased with higher temperature, but fell with increasing pH and the volume ratio of Fe2+ and tea extract. Scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), Fourier transform infrared spectroscope (FTIR) and X-ray diffraction (XRD) indicated that Fe NPs were spherical in shape, their diameter was 70-80 nm and they were mainly composed of iron oxide nanoparticles. UV-visible (UV-vis) indicated that reactivity of Fe NPs used in degradation of MG significantly depended on the synthesized conditions of Fe NPs. This was due to their impact on the reactivity and morphology of Fe NPs. Finally, degradation of MG showed that 90.56% of MG was removed using Fe NPs.

  13. Laboratory test methods to determine the degradation of plastics in marine environmental conditions.

    Science.gov (United States)

    Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

    2012-01-01

    In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9 months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break = -66% in 2 years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment.

  14. Degradation of sustainable mulch materials in two types of soil under laboratory conditions

    Science.gov (United States)

    Villena, Jaime; González, Sara; Moreno, Carmen; Aceituno, Patricia; Campos, Juan; Meco, Ramón; María Moreno, Marta

    2017-04-01

    Mulching is a technique used in cultivation worldwide, especially for vegetable crops, for reducing weed growth, minimising or eliminating soil erosion, and often for enhancing total yields. Manufactured plastic films, mainly polyethylene (PE), have been widely used for this purpose due to their excellent mechanical properties, light weight and relatively low prices in recent years. However, the use of PE is associated with serious environmental problems related to its petrochemical origin and its long shelf-life, which causes a waste problem in our crop fields. For this reason, the use of biodegradable mulch materials (biopolymers and papers) as alternative to PE is increasing nowadays, especially in organic farming. However, these materials can suffer an undesirable early degradation (and therefore not fulfilling their function successfully), greatly resulting from the type of soil. For this reason, this study aimed to analyse the degradation pattern of different mulch materials buried in two types of soils, clay and sand, under laboratory conditions (25°C, dark surroundings, constant humidity). The mulch materials used were: 1) black polyethylene (15 µm); black biopolymers (15 µm): 2) maize starch-based, 3) potato starch-based, 4) polylactic acid-based, 5) black paper, 85 g/m2. Periodically (every 15-20 days), the weight and surface loss of the different materials were recorded. The results indicate that mulch degradation was earlier and higher in the clay soil, especially in the paper and in the potato starch-based materials, followed by the maize starch-based mulch, while polylactic acid-based suffered the least and the latest degradation. Keywords: mulch, biodegradable, biopolymer, paper, degradation. Acknowledgements: the research was funded by Project RTA2011-00104-C04-03 from the INIA (Spanish Ministry of Economy and Competitiveness).

  15. Laboratory Test Methods to Determine the Degradation of Plastics in Marine Environmental Conditions

    Science.gov (United States)

    Tosin, Maurizio; Weber, Miriam; Siotto, Michela; Lott, Christian; Degli Innocenti, Francesco

    2012-01-01

    In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain). However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing) as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation). Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi) was shown to degrade (total disintegration achieved in less than 9 months) when buried in wet sand (simulation test of the tidal zone), to lose mechanical properties but still maintain integrity (tensile strength at break = −66% in 2 years) when exposed to sea water in an aquarium (simulation of pelagic domain), and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88%) when located at the sediment/sea water interface (simulation of benthic domain). This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment. PMID:22737147

  16. Laboratory test methods to determine the degradation of plastics in marine environmental conditions

    Directory of Open Access Journals (Sweden)

    Maurizio eTosin

    2012-06-01

    Full Text Available In this technology report, three test methods were developed to characterize the degradation of plastic in marine environment. The aim was to outline a test methodology to measure the physical and biological degradation in different habitats where plastic waste can deposit when littered in the sea. Previously, research has focused mainly on the conditions encountered by plastic items when floating in the sea water (pelagic domain. However, this is just one of the possible habitats that plastic waste can be exposed to. Waves and tides tend to wash up plastic waste on the shoreline, which is also a relevant habitat to be studied. Therefore, the degradation of plastic items buried under sand kept wet with sea water has been followed by verifying the disintegration (visual disappearing as a simulation of the tidal zone. Most biodegradable plastics have higher densities than water and also as a consequence of fouling, they tend to sink and lay on the sea floor. Therefore, the fate of plastic items lying on the sediment has been followed by monitoring the oxygen consumption (biodegradation. Also the effect of a prolonged exposure to the sea water, to simulate the pelagic domain, has been tested by measuring the decay of mechanical properties. The test material (Mater-Bi was shown to degrade (total disintegration achieved in less than 9 months when buried in wet sand (simulation test of the tidal zone, to lose mechanical properties but still maintain integrity (tensile strength at break = -66% in 2 years when exposed to sea water in an aquarium (simulation of pelagic domain, and substantially biodegrade (69% in 236 days; biodegradation relative to paper: 88% when located at the sediment/sea water interface (simulation of benthic domain. This study is not conclusive as the methodological approach must be completed by also determining degradation occurring in the supralittoral zone, on the deep sea floor, and in the anoxic sediment.

  17. Degradation testing and failure analysis of DC film capacitors under high humidity conditions

    DEFF Research Database (Denmark)

    Wang, Huai; Nielsen, Dennis Achton; Blaabjerg, Frede

    2015-01-01

    Metallized polypropylene film capacitors are widely used for high-voltage DC-link applications in power electronic converters. They generally have better reliability performance compared to aluminum electrolytic capacitors under electro-thermal stresses within specifications. However......, the degradation of the film capacitors is a concern in applications exposed to high humidity environments. This paper investigates the degradation of a type of plastic-boxed metallized DC film capacitors under different humidity conditions based on a total of 8700 h of accelerated testing and also post failure...... of interest is also presented. The study enables a better understanding of the humidity-related failure mechanisms and reliability performance of DC film capacitors for power electronics applications....

  18. Cultivation and characters of aerobic granules for pentachlorophenol (PCP) degradation under microaerobic condition

    Institute of Scientific and Technical Information of China (English)

    LAN Hui-xia; CHEN Yuan-cai; CHEN Zhong-hao; CHEN Rong

    2005-01-01

    Cultivation of aerobic granular sludge for pentachlorophenol (PCP) degradation under microaerobic condition ( DO concentration was controlled at 0.2-0.7 mg/L) was studied in this paper. Anaerobic granules were selected as inoculum. The changes of appearance were observed and the variations of SVI, VSS/TSS, PN/PS and the size of sludge were measured during cultivating. The capabilities for degradation of PCP, AOX and CODcr were also studied. Observations on mature granules were carried out by scanning electron microscope, and the results indicated bacillus was dominant on the surface of granules while in the inner of granules both bacillus and coccus were the dominant microorganisms. K, Na, Fe, Ca, Mg, Ni, Co, Mn, Cu and Zn were detected in the granules by element analysis.

  19. An innovative wheel–rail contact model for railway vehicles under degraded adhesion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Meli, E., E-mail: enrico.meli@unifi.it; Ridolfi, A., E-mail: a.ridolfi@unifi.it [University of Florence, Department of Industrial Engineering (Italy)

    2015-03-15

    The accurate modelling of the wheel–rail contact plays a fundamental role in the railway field since the contact forces heavily affect the vehicle dynamics, the wear of the contact surfaces and the vehicle safety. Concerning the wheel–rail contact, an important open problem is represented by the degraded adhesion. A realistic adhesion model is quite difficult to obtain because of the complex and highly non-linear behaviour of the adhesion coefficient and the presence of external unknown contaminants (the third body); this is especially true when degraded adhesion and large sliding between the wheel and rail contact surfaces occur.In this work the authors present an adhesion model particularly developed to describe degraded adhesion conditions. The new approach will have to be suitable to be employed within the wheel–rail contact models typical of the multibody applications. In other words, the contact model, comprising the new adhesion model, will have to guarantee a good accuracy and, at the same time, a high numerical efficiency to be implemented directly online inside the general multibody model of the vehicles (e.g. in Matlab-Simulink or Simpack environments) ( www.mathworks.com http://www.mathworks.com , 2012; www.simpack.com http://www.simpack.com , 2012).The model analysed in the paper is based on some of the main phenomena characterising the degraded adhesion, such as large sliding at the contact interface, high energy dissipation, the consequent cleaning effect on the contact surfaces and the final adhesion recovery due to the removal of external unknown contaminants.The adhesion model has been validated because of the experimental data provided by Trenitalia S.p.A. coming from on-track tests performed in Velim (Czech Republic). The tests have been carried out on a straight railway track under degraded adhesion conditions with the railway vehicle UIC-Z1 equipped with a fully-working Wheel Slide Protection (WSP) system.The validation highlighted the

  20. Degradation of indomethacin in river water under stress and non-stress laboratory conditions: degradation products, long-term evolution and adsorption to sediment.

    Science.gov (United States)

    Jiménez, Juan J; Sánchez, María I; Pardo, Rafael; Muñoz, Beatriz E

    2017-01-01

    The pharmaceutical compound indomethacin is not totally removed in wastewater treatment plants, whose effluents flow into aquatic environments; concentrations in the 0.1-100ng/L range are commonly found in surface waters, and its fate is unknown. Here, biological, photochemical and thermal degradation assays were conducted under stress and non-stress conditions to estimate its degradation rate in river water and establish its degradation products over time. The results revealed that direct sunlight irradiation promoted the complete degradation of indomethacin (2μg/L) in less than 6hr, but indomethacin was detected over a period of 4months when water was kept under the natural day-night cycle and the exposure to sunlight was partially limited, as occurs inside a body of water. The biological degradation in water was negligible, while the hydrolysis at pH7.8 was slow. Residues were monitored by ultra-pressure liquid chromatography/quadrupole time-of-flight/mass spectrometry after solid-phase extraction, and six degradation products were found; their structures were proposed based on the molecular formulae and fragmentation observed in high-resolution tandem mass spectra. 4-Chlorobenzoic and 2-acetamido-5-methoxybenzoic acids were the long-term transformation products, persisting for at least 30weeks in water kept under non-stress conditions. Furthermore, the degradation in the presence of sediment was also monitored over time, with some differences being noted. The adsorption coefficients of indomethacin and degradation products on river sediment were calculated; long-term degradation products did not have significant adsorption to sediment. Copyright © 2016. Published by Elsevier B.V.

  1. Quantitative Study on Exact Reconstruction Sampling Condition in Limited-view CT

    CERN Document Server

    Yan, Bin; Li, Lei; Zhang, Hanming; Wang, Linyuan

    2016-01-01

    In limited-view computed tomography reconstruction, iterative image reconstruction with sparsity-exploiting methods, such as total variation (TV) minimization, inspired by compressive sensing, potentially claims large reductions in sampling requirements. However, a quantitative notion of this claim is non-trivial because of the ill-defined reduction in sampling achieved by the sparsity-exploiting method. In this paper, exact reconstruction sampling condition for limited-view problem is studied by verifying the uniqueness of solution in TV minimization model. Uniqueness is tested by solving a convex optimization problem derived from the sufficient and necessary condition of solution uniqueness. Through this method, the sufficient sampling number of exact reconstruction is quantified for any fixed phantom and settled geometrical parameter in the limited-view problem. This paper provides a reference to quantify the sampling condition. Using Shepp-Logan phantom as an example, the experiment results show the quant...

  2. A degradation study of cefepime hydrochloride in solutions under various stress conditions by TLC-densitometry.

    Science.gov (United States)

    Dąbrowska, Monika; Starek, Małgorzata; Krzek, Jan; Papp, Elżbieta; Król, Piotr

    2015-03-01

    A rapid, accurate and sensitive thin-layer chromatography (TLC) method with densitometric detection has been developed and validated for the determination of cefepime in pharmaceuticals. Chromatographic separation was achieved on a silica gel TLC F254 plates with a mobile phase consisting of ethanol-2-propanol-glacial acetic acid 99.5%-water (4:4:1:3, v/v). Densitometric detection was carried out at wavelength of 266 nm in reflectance/absorbance mode. The validation of the method was found to be satisfactory with high accuracy (from 99.24 to 101.37%) and precision (RSD from 0.06 to 0.36%). Additionally, the stability of cefepime in solution was investigated, including the effect of pH, temperature and incubation time. Favorable retention parameters (Rf , Rs, α) were obtained under the developed conditions, which guaranteed good separation of the studied components. The degradation process of cefepime hydrochloride was described by kinetic and thermodynamic parameters (k, t0.1 , t0.5 and Ea ). Moreover, the chemical properties of degradation products were characterized by the Rf values, absorption spectra, HPLC-MS/MS and TLC-densitometry analysis. As the method could effectively separate the active substance from its main degradation product (1-methylpyrrolidine), it can be employed as a method to indicate the stability of this drug. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Degradation of [(14)C]carfentrazone-ethyl under aerobic aquatic conditions.

    Science.gov (United States)

    Elmarakby, S A; Supplee, D; Cook, R

    2001-11-01

    Carfentrazone-ethyl (CF-E) is an aryl triazolinone reduced-risk herbicide for use on corn, wheat, and soybean. As part of the assessment of its metabolic fate, the aerobic aquatic metabolism of [(14)C]CF-E at a concentration of 0.22 microg/g was investigated. Two separate aquatic sediments (silty clay loam and clay loam soils, flooded with water) were used in the study. At each of eight samplings throughout the 30-day study, the distribution of radioactivity between surface water, sediment, and volatile fractions was assessed. At zero time, the majority of the applied radioactivity was contained in the water layer (83-90%), declining to 70-80% after 30 days. This was coupled with an increase in the percent radioactivity in the soil layer from 4-6% at day 0 to 13-19% after 30 days. Nonextractable soil residues and volatile degradation products were formed in negligible amounts. Analysis of the incubation extracts from either aquatic sediment indicated a rapid conversion (90% of the applied radioactivity were formed. Identification of these degradation products was initially achieved through chromatographic comparison with reference synthetic standards and subsequently confirmed using LC-MS analysis. A degradation pathway for CF-E under aerobic aquatic conditions is proposed.

  4. Conditional involvement of constitutive photomorphogenic1 in the degradation of phytochrome A.

    Science.gov (United States)

    Debrieux, Dimitry; Trevisan, Martine; Fankhauser, Christian

    2013-04-01

    All higher plants possess multiple phytochrome photoreceptors, with phytochrome A (phyA) being light labile and other members of the family being relatively light stable (phyB-phyE in Arabidopsis [Arabidopsis thaliana]). phyA also differs from other members of the family because it enables plants to deetiolate in far-red light-rich environments typical of dense vegetational cover. Later in development, phyA counteracts the shade avoidance syndrome. Light-induced degradation of phyA favors the establishment of a robust shade avoidance syndrome and was proposed to be important for phyA-mediated deetiolation in far-red light. phyA is ubiquitylated and targeted for proteasome-mediated degradation in response to light. Cullin1 and the ubiquitin E3 ligase constitutive photomorphogenic1 (COP1) have been implicated in this process. Here, we systematically analyze the requirement of cullins in this process and show that only CULLIN1 plays an important role in light-induced phyA degradation. In addition, the role of COP1 in this process is conditional and depends on the presence of metabolizable sugar in the growth medium. COP1 acts with SUppressor of phytochrome A (SPA) proteins. Unexpectedly, the light-induced decline of phyA levels is reduced in spa mutants irrespective of the growth medium, suggesting a COP1-independent role for SPA proteins.

  5. Conditional Involvement of CONSTITUTIVE PHOTOMORPHOGENIC1 in the Degradation of Phytochrome A1[W][OA

    Science.gov (United States)

    Debrieux, Dimitry; Trevisan, Martine; Fankhauser, Christian

    2013-01-01

    All higher plants possess multiple phytochrome photoreceptors, with phytochrome A (phyA) being light labile and other members of the family being relatively light stable (phyB–phyE in Arabidopsis [Arabidopsis thaliana]). phyA also differs from other members of the family because it enables plants to deetiolate in far-red light-rich environments typical of dense vegetational cover. Later in development, phyA counteracts the shade avoidance syndrome. Light-induced degradation of phyA favors the establishment of a robust shade avoidance syndrome and was proposed to be important for phyA-mediated deetiolation in far-red light. phyA is ubiquitylated and targeted for proteasome-mediated degradation in response to light. Cullin1 and the ubiquitin E3 ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) have been implicated in this process. Here, we systematically analyze the requirement of cullins in this process and show that only CULLIN1 plays an important role in light-induced phyA degradation. In addition, the role of COP1 in this process is conditional and depends on the presence of metabolizable sugar in the growth medium. COP1 acts with SUPPRESSOR OF PHYTOCHROME A (SPA) proteins. Unexpectedly, the light-induced decline of phyA levels is reduced in spa mutants irrespective of the growth medium, suggesting a COP1-independent role for SPA proteins. PMID:23391578

  6. The non-oxidative degradation of ascorbic acid at physiological conditions.

    Science.gov (United States)

    Simpson, G L; Ortwerth, B J

    2000-04-15

    The degradation of L-ascorbate (AsA) and its primary oxidation products, L-dehydroascorbate (DHA) and 2,3-L-diketogulonate (2, 3-DKG) were studied under physiological conditions. Analysis determined that L-erythrulose (ERU) and oxalate were the primary degradation products of ASA regardless of which compound was used as the starting material. The identification of ERU was determined by proton decoupled (13)C-nuclear magnetic resonance spectroscopy, and was quantified by high performance liquid chromatography, and enzymatic analysis. The molar yield of ERU from 2,3-DKG at pH 7.0 37 degrees C and limiting O(2)97%. This novel ketose product of AsA degradation, was additionally qualitatively identified by gas-liquid chromatography, and by thin layer chromatography. ERU is an extremely reactive ketose, which rapidly glycates and crosslinks proteins, and therefore may mediate the AsA-dependent modification of protein (ascorbylation) seen in vitro, and also proposed to occur in vivo in human lens during diabetic and age-onset cataract formation.

  7. Physics Based Degradation Models for Capacitor Prognostics under Thermal Overstress Conditions

    Directory of Open Access Journals (Sweden)

    Kai Goebel

    2013-01-01

    Full Text Available Electronics subsystems for monitoring, control, and enhanced functionality play an increasingly important role in safety critical systems. Electrolytic capacitors are an important component in several key subsystems that range from power supplies on safety critical avionics equipment to power drivers for electro-mechanical actuators. These capacitors are known to have comparatively low reliability, and given their criticality in electronics subsystems they are a good candidate for component level monitoring and prognostics. Prognostics provides a way to assess remaining useful life of components and systems based on their current state of health and their anticipated future use and operating conditions. Past experiences have shown that capacitor degradation and failures are quite prevalent under high electrical and thermal stress conditions that they are often subjected to during operations. Our focus in this work is on deriving a physics-based degradation model for electrolytic capacitors under thermal stress conditions. As part of our methodology, we study the effects of accelerated aging due to thermal stress on a batch of identically manufactured capacitors operating at different temperatures. This provides a framework for supplementing theoretical modeling with data collected from simultaneous experiments, which is then used to validate the derived models.

  8. Real-time mass spectroscopy analysis of Li-ion battery electrolyte degradation under abusive thermal conditions

    Science.gov (United States)

    Gaulupeau, B.; Delobel, B.; Cahen, S.; Fontana, S.; Hérold, C.

    2017-02-01

    The lithium-ion batteries are widely used in rechargeable electronic devices. The current challenges are to improve the capacity and safety of these systems in view of their development to a larger scale, such as for their application in electric and hybrid vehicles. Lithium-ion batteries use organic solvents because of the wide operating voltage. The corresponding electrolytes are usually based on combinations of linear, cyclic alkyl carbonates and a lithium salt such as LiPF6. It has been reported that in abusive thermal conditions, a catalytic effect of the cathode materials lead to the formation fluoro-organics compounds. In order to understand the degradation phenomenon, the study at 240 °C of the interaction between positive electrode materials (LiCoO2, LiNi1/3Mn1/3Co1/3O2, LiMn2O4 and LiFePO4) and electrolyte in dry and wet conditions has been realized by an original method which consists in analyzing by mass spectrometry in real time the volatile molecules produced. The evolution of specific gases channels coupled to the NMR reveal the formation of rarely discussed species such as 2-fluoroethanol and 1,4-dioxane. Furthermore, it appears that the presence of water or other protic impurities greatly influence their formation.

  9. An NMR Study of the Bortezomib Degradation under Clinical Use Conditions

    Directory of Open Access Journals (Sweden)

    Adele Bolognese

    2009-01-01

    Full Text Available The (R-3-methyl-1-((S-3-phenyl-2-(pyrazine-2-carboxamidopropanamidobutyl-boronic acid, bortezomib (BTZ, which binds the 20S proteasome subunit and causes a large inhibition of its activity, is a peptidomimetic boronic drug mainly used for the treatment of multiple myeloma. Commercial BTZ, stabilized as mannitol derivative, has been investigated under the common conditions of the clinical use because it is suspected to be easily degradable in the region of its boronic moiety. Commercial BTZ samples, reconstituted according to the reported commercial instructions and stored at 4∘C, were analyzed by high-field nuclear magnetic resonance spectroscopy in comparison with identical samples bubbled with air and argon, respectively. All the samples remained unchanged for a week. After a month, the air filled samples showed the presence of two main degradation products (6% of starting material, the N-(1-(1-hydroxy-3-methylbutylamino-1-oxo-3-phenylpropan-2-yl pyrazine-2-carboxamide (BTZ1; 5%, determined from NMR integration and the (S-N-(1-(3-methylbutanamido-1-oxo-3-phenylpropan-2-ylpyrazine-2-carboxamide (BTZ2; 1%, determined from NMR integration, identified on the basis of their chemical and spectroscopic properties. The BTZ1 and BTZ2 finding suggests that, under the common condition of use and at 4∘C, commercial BTZ-mannitol is stable for a week, and that, in time, it undergoes slow oxidative deboronation which partially inactivates the product. Low temperature and scarce contact with air decrease the degradation process.

  10. Modeling microbial degradation of propylene glycol: electron acceptors and their related redox conditions

    Science.gov (United States)

    Dathe, Annette; Fernandez, Perrine M.; Bloem, Esther; Meeussen, Johannes C. L.; French, Helen K.

    2014-05-01

    De-icing chemicals are applied in large amounts at airports during winter conditions to keep the runways and aircrafts ice-free. The commonly used propylene glycol (PG) is easily degradable by local microbial communities, but anoxic zones develop and soluble Fe+2 and Mn+2 ions can reach the groundwater. To enhance microbial induced remediation and reduce the release of iron and manganese, it was proposed to add NO3- together with PG. However, experiments conducted in the unsaturated zone at Gardermoen airport, Norway, revealed that manganese and iron were preferred over NO3- as electron acceptor [1]. The objectives of this study are to quantify mechanisms which control the order of reduction processes in an unsaturated sandy soil, and to test whether measured redox potentials can help to determine underlying biogeochemical reactions. We are modelling the microbial degradation of PG using Monod kinetics described for the chemical equilibrium tool ORCHESTRA [2], following an approach of [1]. The model is calibrated against gas measurements of CO2, NO2 and N2 released from batch experiments performed under controlled conditions. Fe+2 and Mn+2 were measured for the start and end of the experiment, as well as bulk resistivity, pH and electrical conductivity. With the calibrated model we are working towards a tool to quantify microbial induced redox reactions under different soil water saturations to account for seasonal water fluxes especially during snowmelt. [1] Schotanus, D., Meeussen, J.C.L., Lissner, H., van der Ploeg, M.J., Wehrer, M., Totsche, K.U., van der Zee, S.E.A.T.M., 2013. Transport and degradation of propylene glycol in the vadose zone: model development and sensitivity analysis. Environ Sci Pollut Res Int. [2] Meeussen, J.C.L., 2003. ORCHESTRA: An Object-Oriented Framework for Implementing Chemical Equilibrium Models. Environ. Sci. Technol. 37, 1175-1182.

  11. Study of the degradations caused by nuclear accidental conditions on a steel coating

    Energy Technology Data Exchange (ETDEWEB)

    Ayrinhac, F.; Terriol, J.M. [EDF Ceidre TEGG (France)

    2011-07-01

    The coatings used in nuclear power plants have an interest to make surfaces easily decontaminated and to protect carbon steel (liner and steelworks) from the corrosion. However, in the event of accidental conditions, in particular combining radiation and fast increase of temperature and pressure, these paintings must not constitute an uncontrolled source of debris which may block the safety related functions of core cooling. This experimental study reports the influence of thickness and colour of the withstanding of a steel coating during accidental conditions. The steel coating chosen has been qualified for the liner containment of EDF new generation nuclear power plants (EPR). According to its data sheet, it is composed of an anti-corrosion primer (45 {mu}m), of an intermediate coat (same nature than the primer, 45 {mu}m) and a top coat (50 {mu}m). The system, applied using an conventional spray, was studied by optical and electronic microscopy. After gun airless application and drying, steel samples underwent an irradiation test, a LOCA test followed by a post-accident (100 C an d 100% HR during 10 days). Microscopic analysis by SEM and optical microscopy were carried out in order to evaluate and compare degradations of samples. In conclusion, whatever the color chosen or the thickness obtained, the primers and second coat ('internal layer') do not undergo significant evolution during the test. The greatest part of degradations is inflicted on the top coat. These degradations take the form of vacuums of two types, micro-porosity (few microns diameter) and surface blisters connected with internal spherical vacuums of size ranging between 8 and 50 {mu}m

  12. Degradation of fenamiphos in soils collected from different geographical regions: the influence of soil properties and climatic conditions.

    Science.gov (United States)

    Cáceres, Tanya; Megharaj, Mallavarapu; Naidu, Ravi

    2008-05-01

    The persistence of fenamiphos (nematicide) in five soils collected from different geographical regions such as Australia, Ecuador and India under three temperature regimes (18, 25 and 37 degrees C) simulating typical environmental conditions was studied. The effect of soil properties (soil pH, temperature and microbial biomass) on the degradation of fenamiphos was determined. The rate of degradation increased with increase in temperature. Fenamiphos degradation was higher at 37 degrees C than at 25 and 18 degrees C (except under alkaline pH). The degradation pathway differed in different soils. Fenamiphos sulfoxide (FSO) was identified as the major degradation product in all the soils. Fenamiphos sulfone (FSO2), and the corresponding phenols: fenamiphos phenol (FP), fenamiphos sulfoxide phenol (FSOP) and fenamiphos sulfone phenol (FSO2P) were also detected. The degradation of fenamiphos was faster in the alkaline soils, followed by neutral and acidic soils. Under sterile conditions, the dissipation of the pesticide was slower than in the non-sterile soils suggesting microbial role in the pesticide degradation. The generation of new knowledge on fenamiphos degradation patterns under different environmental conditions is important to achieve better pesticide risk management.

  13. Performance degradation of a typical twin engine commuter type aircraft in measured natural icing conditions

    Science.gov (United States)

    Ranaudo, R. J.; Mikkelsen, K. L.; Mcknight, R. C.; Perkins, P. J., Jr.

    1984-01-01

    The performance of an aircraft in various measured icing conditions was investigated. Icing parameters such as liquid water content, temperature, cloud droplet sizes and distributions were measured continuously while in icinig. Flight data wre reduced to provide plots of the aircraft drag polars and lift curves (CL vs. alpha) for the measured 'iced' condition as referenced to the uniced aircraft. These data were also reduced to provide plots of thrust horsepower required vs. single engine power available to show how icing affects engine out capability. It is found that performance degradation is primarily influenced by the amount and shape of the accumulated ice. Glaze icing caused the greatest aerodynamic performance penalties in terms of increased drag and reduction in lift while aerodynamic penalties due to rime icing were significantly lower. Previously announced in STAR as N84-13173

  14. The Views of New Teachers at Private Teaching Institutions about Working Conditions

    Science.gov (United States)

    Yilmaz, Kursad; Altinkurt, Yahya

    2011-01-01

    The main purpose of the research was to determine the views of teachers about working conditions working at private teaching institutions for 5 years or less. The research was designed as a phenomenology model. The data were collected by focus group interview technique of qualitative research method. 10 teachers from private teaching institutions…

  15. Quantitative study on exact reconstruction sampling condition by verifying solution uniqueness in limited-view CT.

    Science.gov (United States)

    Yan, Bin; Zhang, Wenkun; Li, Lei; Zhang, Hanming; Wang, Linyuan

    2016-10-01

    In limited-view computed tomography reconstruction, iterative image reconstruction with sparsity-exploiting methods, such as total variation (TV) minimization, inspired by compressive sensing, potentially claims large reductions in sampling requirements. However, a quantitative notion of this claim is non-trivial because of the ill-defined reduction in sampling achieved by the sparsity-exploiting method. In this paper, exact reconstruction sampling condition for limited-view problem is studied by verifying the uniqueness of solution in TV minimization model. Uniqueness is tested by solving a convex optimization problem derived from the sufficient and necessary condition of solution uniqueness. Through this method, the sufficient sampling number of exact reconstruction is quantified for any fixed phantom and settled geometrical parameter in the limited-view problem. This paper provides a reference to quantify the sampling condition. Three phantoms are tested to study the sampling condition of limited view exact reconstruction in this paper. The experiment results show the quantified sampling number and indicate that an object would be accurately reconstructed as the scanning range becomes narrower by increasing sampling number. The increased samplings compensate for the deficiency of the projection angle. However, the lower bound of the scanning range corresponding to three different phantoms are presented, in which an exact reconstruction cannot be obtained once the projection angular is narrowed to this extent no matter how to increase sampling.

  16. Lytic polysaccharide monooxygenases: a crystallographer's view on a new class of biomass-degrading enzymes

    Directory of Open Access Journals (Sweden)

    Kristian E. H. Frandsen

    2016-11-01

    Full Text Available Lytic polysaccharide monooxygenases (LPMOs are a new class of microbial copper enzymes involved in the degradation of recalcitrant polysaccharides. They have only been discovered and characterized in the last 5–10 years and have stimulated strong interest both in biotechnology and in bioinorganic chemistry. In biotechnology, the hope is that these enzymes will finally help to make enzymatic biomass conversion, especially of lignocellulosic plant waste, economically attractive. Here, the role of LPMOs is likely to be in attacking bonds that are not accessible to other enzymes. LPMOs have attracted enormous interest since their discovery. The emphasis in this review is on the past and present contribution of crystallographic studies as a guide to functional understanding, with a final look towards the future.

  17. Screening of tetrachlorodibenzo- p-dioxin-degrading fungi capable of producing extracellular peroxidases under various conditions.

    Science.gov (United States)

    Manji, S; Ishihara, A

    2004-01-01

    Forty-six pulp-bleaching fungi were screened for production of key enzymes for conversion of polychlorinated dibenzo-p-dioxins--lignin peroxidase (LiP), manganese peroxidase (MnP), and manganese-independent peroxidase (MiP)--under various conditions that would allow their utilization in the environment. Of 38 MnP-producing strains with MiP activity, 22 produced LiP. Three of the new isolates, Bjerkandera sp. strains MS191, MS325, and MS1167, were the best producers of the three different peroxidases, and had reasonable growth rates. The most promising Bjerkandera sp. strain, MS325, exhibited significant levels of LiP and MnP activities under various conditions, e.g., nutrient nitrogen-sufficient or -limited conditions, conditions with or without Mn(II), and changes in temperature (15-37 degrees C). Furthermore, the ability of this strain to degrade 1,3,6,8-tetrachlorodibenzo- p-dioxin was confirmed. The results presented here indicate that utilization of Bjerkandera sp. strain MS325 on a practical scale in the environment has several advantages over many white rot fungi, which produce extracellular peroxidases only under specific conditions such as nutrient limitation.

  18. Microscopic study of surface degradation of glass fiber-reinforced polymer rods embedded in concrete castings subjected to environmental conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Bank, L.C. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Civil and Environmental Engineering; Puterman, M. [Technion, Haifa (Israel). National Building Research Inst.

    1997-12-31

    The surface degradation of glass fiber-reinforced polymer (GFRP) pultruded rods when embedded in concrete castings and subjected to environmental conditioning is discussed in this paper. Investigation of the degradation of the GFRP rods were performed using optical microscopy and scanning electron microscopy (SEM). Unidirectionally reinforced pultruded rods (6.3- and 12.7-mm diameters) containing E-glass fibers in polyester and vinylester matrices were conditioned at standard laboratory conditions (21 C, 65% relative humidity) or submerged in aqueous solutions (tap water) at 80 C for durations of 14 and 84 days. Observations of the surfaces and cross-sections of the rods by optical microscopy and SEM revealed a variety of degradation phenomena. Embedded hygrothermally conditioned rods were found to have developed surface blisters of different sizes and depths. SEM studies of the surface revealed degradation of the polymer matrix material and exposure and degradation of the fibers close to the surface of the rods. The rods with the vinylester resin matrix showed less extensive degradation than those with the polyester resin matrix; however, the degradation characteristics of the two types of rods appear to be similar.

  19. Brain dynamics during natural viewing conditions--a new guide for mapping connectivity in vivo.

    Science.gov (United States)

    Bartels, Andreas; Zeki, Semir

    2005-01-15

    We describe here a new way of obtaining maps of connectivity in the human brain based on interregional correlations of blood oxygen level-dependent (BOLD) signal during natural viewing conditions. We propose that anatomical connections are reflected in BOLD signal correlations during natural brain dynamics. This may provide a powerful approach to chart connectivity, more so than that based on the 'resting state' of the human brain, and it may complement diffusion tensor imaging. Our approach relies on natural brain dynamics and is therefore experimentally unbiased and independent of hypothesis-driven, specialized stimuli. It has the advantage that natural viewing leads to considerably stronger cortical activity than rest, thus facilitating detection of weaker connections. To validate our technique, we used functional magnetic resonance imaging (fMRI) to record BOLD signal while volunteers freely viewed a movie that was interrupted by resting periods. We used independent component analysis (ICA) to segregate cortical areas before characterizing the dynamics of their BOLD signal during free viewing and rest. Natural viewing and rest each revealed highly specific correlation maps, which reflected known anatomical connections. Examples are homologous regions in visual and auditory cortices in the two hemispheres and the language network consisting of Wernicke's area, Broca's area, and a premotor region. Correlations between regions known to be directly connected were always substantially higher than between nonconnected regions. Furthermore, compared to rest, natural viewing specifically increased correlations between anatomically connected regions while it decreased correlations between nonconnected regions. Our findings therefore demonstrate that natural viewing conditions lead to particularly specific interregional correlations and thus provide a powerful environment to reveal anatomical connectivity in vivo.

  20. Condition assessment and trending of condenser tube degradation for condenser life extension

    Science.gov (United States)

    Friant, C. Lee; Schlegel, Jennifer L.

    1995-05-01

    Eddy current testing (ET) is routinely used to assess tubing condition in heat exchangers at power plants. Generally, ET results provided by typical final report formats are not well- suited for facilitating condition assessments, especially when the component has a significant number of tubes. The main condenser at Calvert Cliffs Nuclear Power Plant (CCNPP) Unit #1 contains nearly 50,000 tubes. An accurate condition assessment based on 2,500 pages of final reports generated from a 100% condenser inspection in 1992 proved difficult, if not impossible, without some type of automated data management system. With the aid of a data management system, engineering recommendations, founded on database queries and graphics, can be made quickly and reliably. These displays effectively communicate information about overall condition, are helpful in making operating decisions, and aid in predicting future performance. Standard procedures for critical heat exchanger inspections require trending of indication growth over time to determine a rate of tube degradation. Specifically, for the 1994 ET inspection of CCNPP Unit #1 condenser, the size of indications were compared against their 1992 value to determine a mean growth rate. The results of these efforts are presented along with a discussion of how Baltimore Gas and Electric has used eddy current data to prolong the operating life of this condenser while ensuring leak tightness.

  1. Bacterial degradation of cyanide and its metal complexes under alkaline conditions.

    Science.gov (United States)

    Luque-Almagro, Víctor M; Huertas, María-J; Martínez-Luque, Manuel; Moreno-Vivián, Conrado; Roldán, M Dolores; García-Gil, L Jesús; Castillo, Francisco; Blasco, Rafael

    2005-02-01

    A bacterial strain able to use cyanide as the sole nitrogen source under alkaline conditions has been isolated. The bacterium was classified as Pseudomonas pseudoalcaligenes by comparison of its 16S RNA gene sequence to those of existing strains and deposited in the Coleccion Espanola de Cultivos Tipo (Spanish Type Culture Collection) as strain CECT5344. Cyanide consumption is an assimilative process, since (i) bacterial growth was concomitant and proportional to cyanide degradation and (ii) the bacterium stoichiometrically converted cyanide into ammonium in the presence of l-methionine-d,l-sulfoximine, a glutamine synthetase inhibitor. The bacterium was able to grow in alkaline media, up to an initial pH of 11.5, and tolerated free cyanide in concentrations of up to 30 mM, which makes it a good candidate for the biological treatment of cyanide-contaminated residues. Both acetate and d,l-malate were suitable carbon sources for cyanotrophic growth, but no growth was detected in media with cyanide as the sole carbon source. In addition to cyanide, P. pseudoalcaligenes CECT5344 used other nitrogen sources, namely ammonium, nitrate, cyanate, cyanoacetamide, nitroferricyanide (nitroprusside), and a variety of cyanide-metal complexes. Cyanide and ammonium were assimilated simultaneously, whereas cyanide strongly inhibited nitrate and nitrite assimilation. Cyanase activity was induced during growth with cyanide or cyanate, but not with ammonium or nitrate as the nitrogen source. This result suggests that cyanate could be an intermediate in the cyanide degradation pathway, but alternative routes cannot be excluded.

  2. MICROSTRUCTURE AND MECHANICAL PROPERTIES DEGRADATION OF CrMo CREEP RESISTANT STEEL OPERATING UNDER CREEP CONDITIONS

    Directory of Open Access Journals (Sweden)

    Ján Micheľ

    2011-07-01

    Full Text Available In this contribution microstructure degradation of a steam tube is analysed. The tube is made of CrMo creep resistant steel and was in service under creep conditions at temperature 530°C and calculated stress level in the tube wall 46.5 MPa. During service life in the steel gradual micro structure changes were observed, first pearlite spheroidization, precipitation, coagulation and precipitate coarsening. Despite the fact that there were evident changes in the micro structure the strength and deformation properties of the steel (Re, Rm, A5, Z, the resistance to brittle fracture and the creep strength limit, were near to unchanged after 2.1x10 5 hours in service. The steam tube is now in service more than 2.6x10 5 h.

  3. Degradation of tocopherols during rapeseed storage in simulated conditions of industrial silos

    Science.gov (United States)

    Gawrysiak-Witulska, Marzena; Siger, Aleksander; Rusinek, Robert

    2016-01-01

    The investigations consisted in laboratory simulation of conditions prevailing in the real ecosystem in an industrial rapeseed storage facility. The aim of the study was to assess the impact of temperature, moisture, and static pressure on degradation of tocopherols contained in rapeseed. Rapeseed varieties with high oil content were analysed in the investigations. Samples of seeds with 7, 10, 13, and 16% moisture levels were stored at a temperature of 25, 30, and 35°C in specially designed airtight pressure silos for storage in controlled conditions. During the storage, the seeds were subjected to overpressure in the range of 20-60 kPa. The seeds were stored in these conditions for 28 days. It was demonstrated that primarily moisture induced the greatest loss of the total content of tocopherol and its α-T and γ-T homologues, followed by temperature and, to a lesser extent, pressure. In addition, the results obtained showed that, in the case of seeds characterised by higher moisture levels (13 and 16%), an increase in the storage temperature in the range of 25-30°C rather than 30-35°C intensified tocopherol loss more efficiently.

  4. Biodegradability of biodegradable/degradable plastic materials under aerobic and anaerobic conditions.

    Science.gov (United States)

    Mohee, R; Unmar, G D; Mudhoo, A; Khadoo, P

    2008-01-01

    A study was conducted on two types of plastic materials, Mater-Bi Novamont (MB) and Environmental Product Inc. (EPI), to assess their biodegradability under aerobic and anaerobic conditions. For aerobic conditions, organic fractions of municipal solid wastes were composted. For the anaerobic process, anaerobic inoculum from a wastewater treatment plant was used. Cellulose filter papers (CFP) were used as a positive control for both mediums. The composting process was monitored in terms of temperature, moisture and volatile solids and the biodegradation of the samples were monitored in terms of mass loss. Monitoring results showed a biodegradation of 27.1% on a dry basis for MB plastic within a period of 72 days of composting. Biodegradability under an anaerobic environment was monitored in terms of biogas production. A cumulative methane gas production of 245 ml was obtained for MB, which showed good degradation as compared to CFP (246.8 ml). However, EPI plastic showed a cumulative methane value of 7.6 ml for a period of 32 days, which was close to the blank (4.0 ml). The EPI plastic did not biodegrade under either condition. The cumulative carbon dioxide evolution after 32 days was as follows: CFP 4.406 cm3, MB 2.198 cm3 and EPI 1.328 cm3. The cumulative level of CO2 varying with time fitted sigmoid type curves with R2 values of 0.996, 0.996 and 0.995 for CFP, MB and EPI, respectively.

  5. Ubiquitination is absolutely required for the degradation of hypoxia-inducible factor - 1 alpha protein in hypoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ronghai [Department of Urology, Linzi District People' s Hospital, Zibo, 255400 (China); Zhang, Ping, E-mail: zpskx001@163.com [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Li, Jinhang [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Guan, Hongzai [Laboratory Department, School of Medicine, Qingdao University, Qingdao, 266071 (China); Shi, Guangjun, E-mail: qdmhshigj@yahoo.com [Department of Hepatobiliary Surgery, Qingdao Municipal Hospital, Qingdao, 266071 (China)

    2016-01-29

    The hypoxia-inducible factor (HIF) is recognized as the master regulator of hypoxia response. HIF-α subunits expression are tightly regulated. In this study, our data show that ts20 cells still expressed detectable E1 protein even at 39.5° C for 12 h, and complete depletion of E1 protein expression at 39.5° C by siRNA enhanced HIF-1α and P53 protein expression. Further inhibition of E1 at 39.5 °C by siRNA, or E1 inhibitor Ube1-41 completely blocked HIF-1α degradation. Moreover, immunoprecipitations of co-transfection of HA-ubiquitin and FLAG–HIF–1α plasmids directly confirmed the involvement of ubiquitin in the hypoxic degradation of HIF-1α. Additionally, hypoxic HIF-1 α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization. Taken together, our data suggest that constitutive HIF-1α protein degradation in hypoxia is absolutely ubiquitination-dependent, and unidentified E3 ligase may exist for this degradation pathway. - Highlights: • HIF-1α protein is constitutively degraded in hypoxic conditions. • Requirement of ubiquitination for HIF-1α degradation in hypoxia. • Hypoxic HIF-1α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization.

  6. Selection of the Bacteria Being Able to Degrade Kerosene and Study on the Growth Conditions of the Bacteria

    Institute of Scientific and Technical Information of China (English)

    LI; Ping; ZHUO; Feng-ping; GAO; Li-hong; CAI; Ming

    2012-01-01

    [Objective] The study aimed at selecting the predominant strains being able to degrade kerosene and studying its best growth conditions. [Method] Choosing kerosene as the only carbon source, we selected and separated the predominant strains being able to degrade kerosene from the contaminated soil near petrochemical plants, and then optimized the grow conditions of the bacteria. [Result] The best conditions for the bacteria growth were determined as follows, that is, temperature was 30 ℃, pH=7, salinity was 2.5%, and the rotational speed of the thermostatic shake was 190 r/min. Under the optimal conditions, the degradation rate of kerosene by the bacteria cultured for three days reached 42.6%. [Conclusion] The research could provide scientific references for the restoration of polluted soil by kerosene.

  7. Adaptive strategies of remote systems operators exposed to perturbed camera-viewing conditions

    Science.gov (United States)

    Stuart, Mark A.; Manahan, Meera K.; Bierschwale, John M.; Sampaio, Carlos E.; Legendre, A. J.

    1991-01-01

    This report describes a preliminary investigation of the use of perturbed visual feedback during the performance of simulated space-based remote manipulation tasks. The primary objective of this NASA evaluation was to determine to what extent operators exhibit adaptive strategies which allow them to perform these specific types of remote manipulation tasks more efficiently while exposed to perturbed visual feedback. A secondary objective of this evaluation was to establish a set of preliminary guidelines for enhancing remote manipulation performance and reducing the adverse effects. These objectives were accomplished by studying the remote manipulator performance of test subjects exposed to various perturbed camera-viewing conditions while performing a simulated space-based remote manipulation task. Statistical analysis of performance and subjective data revealed that remote manipulation performance was adversely affected by the use of perturbed visual feedback and performance tended to improve with successive trials in most perturbed viewing conditions.

  8. Microbial degradation of acenapthene and napthalene under denitrification conditions in soil--water systems: Annual report, October 1987

    Energy Technology Data Exchange (ETDEWEB)

    Mihelcic, J.R.; Luthy, R.G.

    1987-10-01

    This study examined the microbial degradation of acenaphthene and naphthalene under denitrification conditions at soil-to-water ratios of 1:25 and 1:50 with soil containing approximately 10/sup 5/ denitrifying organisms per gram of soil. Under nitrate-excess conditions, both acenaphthene and naphthalene were degraded microbially from initial aqueous-phase concentrations of about one and several mg/l, respectively, to nondetectable levels (<0.01 mg/l) in time periods less than 9 weeks. Acclimation periods of 12 to 36 days were observed prior to the onset of microbial degradation in tests with soil not previously exposed to PAH, while acclimation periods were absent in tests with soil reserved from prior PAH degradation tests. It was judged that the apparent acclimation period resulted from the time for a small population of organisms capable of PAH degradation to attain sufficient densities to exhibit detectable PAH reduction. About 0.9 percent of the naturally occurring soil organic carbon could be mineralized under denitrification conditions, and this accounted for the greater proportion of the nitrate depletion. The mineralization of the labile fraction of the soil organic carbon via microbial denitrification occurred without an observed acclimation period, and was rapid compared to PAH degradation. Under nitrate-limiting conditions the PAH compounds were stable owing to the depletion of nitrate via the more rapid process of soil organic carbon mineralization. The microbial degradation of the PAH compound depends on the interrelationships between: the desorption kinetics and the reversibility of desorption of sorbed compound from the soil, the concentration of PAH-degrading microorganisms, and the competing reaction for nitrate utilization via mineralization of the labile fraction of naturally occurring soil organic carbon. 44 refs., 10 figs.

  9. Judgments of the distance to nearby virtual objects: interaction of viewing conditions and accommodative demand.

    Science.gov (United States)

    Ellis, S R; Menges, B M

    1997-08-01

    Ten subjects adjusted a real-object probe to match the distance of nearby virtual objects optically presented via a see-through, helmet-mounted display. Monocular, binocular, and stereoscopic viewing conditions were used with two levels of required focus. Observed errors may be related to changes in the subjects' binocular convergence. The results suggest ways in which virtual objects may be presented with improved spatial fidelity.

  10. Compound specific isotope analysis to investigate pesticide degradation in lysimeter experiments at field conditions

    Science.gov (United States)

    Ryabenko, Evgenia; Elsner, Martin; Bakkour, Rani; Hofstetter, Thomas; Torrento, Clara; Hunkeler, Daniel

    2015-04-01

    The frequent detection of organic micropollutants such as pesticides, consumer care products or pharmaceuticals in water is an increasing concern for human and ecosystem health. Degradation analysis of these compounds can be challenging in complex systems due to the fact that metabolites are not always found and mass balances frequently cannot be closed. Many abiotic and biotic degradation pathways cause, however, distinct isotope fractionation, where light isotopes are transferred preferentially from the reactant to the product pool (normal isotope fractionation). Compound-specific isotope analysis (CSIA) of multiple elements is a particularly powerful method to evaluate organic micropollutant transformation, because it can even give pathway-specific isotope fractionation (1,2). Available CSIA field studies, however, have focused almost exclusively on volatile petroleum and chlorinated hydrocarbons, which are present in high concentrations in the environment and can be extracted easily from water for GC-IRMS analysis. In the case of micropollutants, such as pesticides, CSIA in more challenging since it needs to be conducted at lower concentrations and requires pre-concentration, purification and high chromatographic performance (3). In this study we used lysimeters experiments to analyze transformation of atrazine, acetochlor, metolachlor and chloridazone by studying associated isotope fractionation. The project combines a) analytical method development for CSIA, b) identification of pathways of micropollutant degradation and c) quantification of transformation processes under field condition. The pesticides were applied both, at the soil surface and below the top soil under field-relevant concentrations in May 2014. After typical irrigation of the lysimeters, seepage water was collected in 50L bottles and stored for further SPE and CSIA. Here we present the very first result of a) analytical method development, b) improvement of SPE methods for complex pesticide

  11. Protein degradation by ubiquitin–proteasome system in formation and labilization of contextual conditioning memory

    Science.gov (United States)

    Sol Fustiñana, María; de la Fuente, Verónica; Federman, Noel; Freudenthal, Ramiro

    2014-01-01

    The ubiquitin–proteasome system (UPS) of protein degradation has been evaluated in different forms of neural plasticity and memory. The role of UPS in such processes is controversial. Several results support the idea that the activation of this system in memory consolidation is necessary to overcome negative constrains for plasticity. In this case, the inhibition of the UPS during consolidation impairs memory. Similar results were reported for memory reconsolidation. However, in other cases, the inhibition of UPS had no effect on memory consolidation and reconsolidation but impedes the amnesic action of protein synthesis inhibition after retrieval. The last finding suggests a specific action of the UPS inhibitor on memory labilization. However, another interpretation is possible in terms of the synthesis/degradation balance of positive and negative elements in neural plasticity, as was found in the case of long-term potentiation. To evaluate these alternative interpretations, other reconsolidation-interfering drugs than translation inhibitors should be tested. Here we analyzed initially the UPS inhibitor effect in contextual conditioning in crabs. We found that UPS inhibition during consolidation impaired long-term memory. In contrast, UPS inhibition did not affect memory reconsolidation after contextual retrieval but, in fact, impeded memory labilization, blocking the action of drugs that does not affect directly the protein synthesis. To extend these finding to vertebrates, we performed similar experiments in contextual fear memory in mice. We found that the UPS inhibitor in hippocampus affected memory consolidation and blocked memory labilization after retrieval. These findings exclude alternative interpretations to the requirement of UPS in memory labilization and give evidence of this mechanism in both vertebrates and invertebrates. PMID:25135196

  12. Assessment by HPLC of the degradation behavior of acitretin under hydrolytic, oxidative, photolytic and thermal stress conditions

    Directory of Open Access Journals (Sweden)

    Pawan K. Porwal

    2014-12-01

    Full Text Available Acitretin is a photosensitive oral retinoid with very limited data available on its degradation. The official HPLC method for acitretin determination was insufficient to resolve the degradation products generated during stability studies. Therefore, an isocratic RP-HPLC–UV method was developed for the determination of acitretin in the presence of its related impurities and degradation products. Efficient chromatographic separation was achieved on a Thermo beta-basic column C18 (100 mm×4.6 mm, 5 μm with mobile phase containing 0.3% (v/v glacial acetic acid with acetonitrile (ACN and isopropyl alcohol (IPA in an isocratic ratio of 70:30 at a flow rate of 1.0 mL/min with the eluent monitored at 360 nm. The method was validated for specificity, linearity, precision, accuracy and robustness. The calibration plot was linear over the concentration range of 50–150 μg/mL with a correlation coefficient (r2 of 0.999. The proposed method was used to investigate the degradation kinetics of acitretin under the different degradative conditions. The degradation rate constant (K, half-life (t1/2, and t90 were calculated. Degradation of acitretin followed pseudo-first-order kinetics. The drug was found to be less stable under acidic and photolytic degradation conditions: the photolytic degradation constants for acitretin in sunlight and UV light were 0.002698% and 0.0008402% min−1, respectively. The LOD for acitretin and the known impurities were at a level below 0.02%. The method shows consistent recoveries for ACTR (99.8%–101.2% and also for its known impurities (97.2–101.3%. The method was found to be accurate, precise, linear, specific, sensitive, rugged, robust, and useful for characterizing the stability of this chemical.

  13. Investigation on magnesium degradation under flow versus static conditions using a novel impedance-driven flow apparatus

    Institute of Scientific and Technical Information of China (English)

    Elbert David Mai; Huinan Liu

    2014-01-01

    This article reports a novel impedance-driven flow apparatus and its applicability for studying magnesium degradation under flow versus static conditions. Magnesium has potential to be an effective biomaterial for use inside the human body due to its biodegradability and biocompatibility. Magnesium undergoes degradation reactions in aqueous solutions such as body fluids, leading to mass loss and pH increase of the surrounding fluid. To compare the degradation process of magnesium under flow versus static conditions, a novel flow apparatus consisting of an impedance pump and a flow chamber was designed and constructed. In addition to low-cost, this apparatus is flexible to be sterilized and assembled, and is small enough for use inside an incubator, making it appealing for measuring and comparing magnesium degradation in vitro under flow versus static conditions. The average flow rate in this flow apparatus was 2.8 ml/s, mimicking the flow rate (2.6 ml/s) in coronary artery. In a simulated body fluid (SBF), magnesium samples lost their mass at a much faster rate under the flow condition than that under the static condition. Starting with a pH of 7.4, the SBF showed a pH increase to 8.5 under the flow condition within 96 h due to the degradation of magnesium, greater than the pH increase under the static condition. The results of this study demonstrated the effects of fluid flow on magnesium degradation using the impedance-driven flow apparatus, providing useful design guidelines for magnesium-based implants that may be exposed to body fluid flow.

  14. Progressive degradation of crude oil n-alkanes coupled to methane production under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Cheng, Lei; Shi, Shengbao; Li, Qiang; Chen, Jianfa; Zhang, Hui; Lu, Yahai

    2014-01-01

    Although methanogenic degradation of hydrocarbons has become a well-known process, little is known about which crude oil tend to be degraded at different temperatures and how the microbial community is responded. In this study, we assessed the methanogenic crude oil degradation capacity of oily sludge microbes enriched from the Shengli oilfield under mesophilic and thermophilic conditions. The microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of 16S rRNA genes combined with cloning and sequencing. Enrichment incubation demonstrated the microbial oxidation of crude oil coupled to methane production at 35 and 55°C, which generated 3.7±0.3 and 2.8±0.3 mmol of methane per gram oil, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that crude oil n-alkanes were obviously degraded, and high molecular weight n-alkanes were preferentially removed over relatively shorter-chain n-alkanes. Phylogenetic analysis revealed the concurrence of acetoclastic Methanosaeta and hydrogenotrophic methanogens but different methanogenic community structures under the two temperature conditions. Candidate divisions of JS1 and WWE 1, Proteobacteria (mainly consisting of Syntrophaceae, Desulfobacteraceae and Syntrophorhabdus) and Firmicutes (mainly consisting of Desulfotomaculum) were supposed to be involved with n-alkane degradation in the mesophilic conditions. By contrast, the different bacterial phylotypes affiliated with Caldisericales, "Shengli Cluster" and Synergistetes dominated the thermophilic consortium, which was most likely to be associated with thermophilic crude oil degradation. This study revealed that the oily sludge in Shengli oilfield harbors diverse uncultured microbes with great potential in methanogenic crude oil degradation over a wide temperature range, which extend our previous understanding of methanogenic degradation of crude oil alkanes.

  15. Progressive degradation of crude oil n-alkanes coupled to methane production under mesophilic and thermophilic conditions.

    Directory of Open Access Journals (Sweden)

    Lei Cheng

    Full Text Available Although methanogenic degradation of hydrocarbons has become a well-known process, little is known about which crude oil tend to be degraded at different temperatures and how the microbial community is responded. In this study, we assessed the methanogenic crude oil degradation capacity of oily sludge microbes enriched from the Shengli oilfield under mesophilic and thermophilic conditions. The microbial communities were investigated by terminal restriction fragment length polymorphism (T-RFLP analysis of 16S rRNA genes combined with cloning and sequencing. Enrichment incubation demonstrated the microbial oxidation of crude oil coupled to methane production at 35 and 55°C, which generated 3.7±0.3 and 2.8±0.3 mmol of methane per gram oil, respectively. Gas chromatography-mass spectrometry (GC-MS analysis revealed that crude oil n-alkanes were obviously degraded, and high molecular weight n-alkanes were preferentially removed over relatively shorter-chain n-alkanes. Phylogenetic analysis revealed the concurrence of acetoclastic Methanosaeta and hydrogenotrophic methanogens but different methanogenic community structures under the two temperature conditions. Candidate divisions of JS1 and WWE 1, Proteobacteria (mainly consisting of Syntrophaceae, Desulfobacteraceae and Syntrophorhabdus and Firmicutes (mainly consisting of Desulfotomaculum were supposed to be involved with n-alkane degradation in the mesophilic conditions. By contrast, the different bacterial phylotypes affiliated with Caldisericales, "Shengli Cluster" and Synergistetes dominated the thermophilic consortium, which was most likely to be associated with thermophilic crude oil degradation. This study revealed that the oily sludge in Shengli oilfield harbors diverse uncultured microbes with great potential in methanogenic crude oil degradation over a wide temperature range, which extend our previous understanding of methanogenic degradation of crude oil alkanes.

  16. 360⁰ -View of Quantum Theory and Ab Initio Simulation at Extreme Conditions: 2014 Sanibel Symposium

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hai-Ping [Univ. of Florida, Gainesville, FL (United States)

    2016-09-02

    The Sanibel Symposium 2014 was held February 16-21, 2014, at the King and Prince, St. Simons Island, GA. It was successful in bringing condensed-matter physicists and quantum chemists together productively to drive the emergence of those specialties. The Symposium had a significant role in preparing a whole generation of quantum theorists. The 54th Sanibel meeting looked to the future in two ways. We had 360⁰-View sessions to honor the exceptional contributions of Rodney Bartlett (70), Bill Butler (70), Yngve Öhrn (80), Fritz Schaefer (70), and Malcolm Stocks (70). The work of these five has greatly impacted several generations of quantum chemists and condensed matter physicists. The “360⁰” is the sum of their ages. More significantly, it symbolizes a panoramic view of critical developments and accomplishments in theoretical and computational chemistry and physics oriented toward the future. Thus, two of the eight 360⁰-View sessions focused specifically on younger scientists. The 360⁰-View program was the major component of the 2014 Sanibel meeting. Another four sessions included a sub-symposium on ab initio Simulations at Extreme Conditions, with focus on getting past the barriers of present-day Born-Oppenheimer molecular dynamics by advances in finite-temperature density functional theory, orbital-free DFT, and new all-numerical approaches.

  17. 360⁰ -View of Quantum Theory and Ab Initio Simulation at Extreme Conditions: 2014 Sanibel Symposium

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hai-Ping [Univ. of Florida, Gainesville, FL (United States)

    2016-09-02

    The Sanibel Symposium 2014 was held February 16-21 2014 at the King and Prince, St. Simons Island, GA. It was successful in bringing condensed-matter physicists and quantum chemists together productively to drive the emergence of those specialties. The Symposium had a significant role in preparing a whole generation of quantum theorists. The 54th Sanibel meeting looked to the future in two ways. We had 360⁰-View sessions to honor the exceptional contributions of Rodney Bartlett (70), Bill Butler (70), Yngve Öhrn (80), Fritz Schaefer (70), and Malcolm Stocks (70). The work of these five has greatly impacted several generations of quantum chemists and condensed matter physicists. The “360⁰” is the sum of their ages. More significantly, it symbolizes a panoramic view of critical developments and accomplishments in theoretical and computational chemistry and physics oriented toward the future. Thus, two of the eight 360⁰-View sessions focused specifically on younger scientists. The 360⁰-View program was the major component of the 2014 Sanibel meeting. Another four sessions included a sub-symposium on ab initio Simulations at Extreme Conditions, with focus on getting past the barriers of present-day Born-Oppenheimer molecular dynamics by advances in finite-temperature density functional theory, orbital-free DFT, and new all-numerical approaches.

  18. Screening a Strain of Aspergillus niger and Optimization of Fermentation Conditions for Degradation of Aflatoxin B1

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-11-01

    Full Text Available Aflatoxin B1, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1 was able to degrade aflatoxin B1 after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B1 after 48 h of fermentation in nutrient broth (NB. Optimization of fermentation conditions for aflatoxin B1 degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B1 was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B1 degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B1 degradation by the supernatant were examined. Results indicated that aflatoxin B1 degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.

  19. Proton exchange membrane fuel cell degradation under close to open-circuit conditions. Part I: In situ diagnosis

    Science.gov (United States)

    Wu, Jinfeng; Yuan, Xiao-Zi; Martin, Jonathan J.; Wang, Haijiang; Yang, Daijun; Qiao, Jinli; Ma, Jianxin

    Durability of polymer exchange membrane (PEM) fuel cells under a wide range of operational conditions has been generally identified as one of the top technical gaps that need to be overcome for the acceptance of this fuel cell technology as a commercially viable power source, especially for automotive and portable applications. In this study, a 1200 h lifetime test was conducted with a six-cell PEM fuel cell stack under close to open-circuit conditions. In situ measurements of the hydrogen crossover rate through the membrane, high frequency resistance and electrochemically active surface area of each single cell, in combination with cell polarization curves, were used to investigate the degradation mechanisms. Direct gas mass spectrometry of the cathode exhaust gas indicated the formation of HF, H 2O 2 and CO 2 during the durability testing. The overall cell degradation rate under this accelerated stress testing is approximately 0.128 mV h -1. The cell degradation rate for the first 800 h is much lower than that after 800 h, which may result from the dominance of different degradation mechanisms. For the first period, the degradation of fuel cell performance was mainly attributed to catalyst decay, while the subsequent dramatic degradation is likely caused by membrane failure.

  20. Physics based Degradation Modeling and Prognostics of Electrolytic Capacitors under Electrical Overstress Conditions

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper proposes a physics based degradation modeling and prognostics approach for electrolytic capacitors. Electrolytic capacitors are critical components in...

  1. Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

    OpenAIRE

    Prakash, Indra; Chaturvedula, Venkata; Markosyan, Avetik

    2014-01-01

    Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) &

  2. Structural characterization of the degradation products of a minor natural sweet diterpene glycoside Rebaudioside M under acidic conditions.

    Science.gov (United States)

    Prakash, Indra; Chaturvedula, Venkata Sai Prakash; Markosyan, Avetik

    2014-01-14

    Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) & 2D (COSY, HSQC, HMBC) NMR, HRMS, MS/MS spectral data as well as enzymatic and acid hydrolysis studies.

  3. Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

    OpenAIRE

    Indra Prakash; Venkata Sai Prakash Chaturvedula; Avetik Markosyan

    2014-01-01

    Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) &...

  4. Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

    OpenAIRE

    Prakash, Indra; Chaturvedula, Venkata Sai Prakash; Markosyan, Avetik

    2014-01-01

    Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) & 2D ...

  5. Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

    Directory of Open Access Journals (Sweden)

    Indra Prakash

    2014-01-01

    Full Text Available Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0 and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C- & 2D (COSY, HSQC, HMBC NMR, HRMS, MS/MS spectral data as well as enzymatic and acid hydrolysis studies.

  6. Structural Characterization of the Degradation Products of a Minor Natural Sweet Diterpene Glycoside Rebaudioside M under Acidic Conditions

    Science.gov (United States)

    Prakash, Indra; Chaturvedula, Venkata Sai Prakash; Markosyan, Avetik

    2014-01-01

    Degradation of rebaudioside M, a minor sweet component of Stevia rebaudiana Bertoni, under conditions that simulated extreme pH and temperature conditions has been studied. Thus, rebaudioside M was treated with 0.1 M phosphoric acid solution (pH 2.0) and 80 °C temperature for 24 h. Experimental results indicated that rebaudioside M under low pH and higher temperature yielded three minor degradation compounds, whose structural characterization was performed on the basis of 1D (1H-, 13C-) & 2D (COSY, HSQC, HMBC) NMR, HRMS, MS/MS spectral data as well as enzymatic and acid hydrolysis studies. PMID:24424316

  7. Air-condition Control System of Weaving Workshop Based on LabVIEW

    Science.gov (United States)

    Song, Jian

    The project of air-condition measurement and control system based on LabVIEW is put forward for the sake of controlling effectively the environmental targets in the weaving workshop. In this project, which is based on the virtual instrument technology and in which LabVIEW development platform by NI is adopted, the system is constructed on the basis of the virtual instrument technology. It is composed of the upper PC, central control nodes based on CC2530, sensor nodes, sensor modules and executive device. Fuzzy control algorithm is employed to achieve the accuracy control of the temperature and humidity. A user-friendly man-machine interaction interface is designed with virtual instrument technology at the core of the software. It is shown by experiments that the measurement and control system can run stably and reliably and meet the functional requirements for controlling the weaving workshop.

  8. Evaluation of the performance degradation at PAFC effect of operating conditions on acid loss

    Energy Technology Data Exchange (ETDEWEB)

    Miyoshi, Hideaki; Uchida, Hiroyuki; Watanabe, Masahiro [Yamanashi Univ., Kofu (Japan)] [and others

    1996-12-31

    As a complimentary 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 conducted by NEDO, with the objective of establishing an estimation method for the service life-time of the cell stacks. As part of this project, this work has been performed to clarify basic phenomena of the performance degradation at PAFCs jointly by Yamanashi University, PAFC-TRA and PAFC manufacturers. The acid loss into exhaust gases is one of life limiting factors in PAFCs. To design the cells of long-life, it is important to estimate the phosphoric acid loss and to contrive ideas eliminating it. With the objective of obtaining basic data for simulating the acid loss in the large size cells, the effect of the operating conditions on the acid loss into exhaust gases has been studied experimentally by using a single cell with an active electrode area of 100 cm{sup 2}.

  9. Main mechanisms of material properties degradation under reactor pressure vessel operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Karzov, Georgy; Timofeev, Boris [Central Research Inst. of Structural Materials ' prometey' , St. Petersburg (Russian Federation)

    1999-07-01

    In the process of NPP equipment operation materials are subjected to a prolonged influence of loads, associated with the variation of inner pressure and temperature under various conditions. Each equipment element damage is associated with some material fracture mechanism. For NPP equipment the mechanisms of irreversible damage accumulation are related with: irradiation embrittlement, thermal and strain aging, fatigue damages from mechanical and thermal loading, stress corrosion and fatigue corrosion, creep and thermal relaxation stresses, erosion and weak, thermal shock. The basic tasks of specialists working in the sphere of the provision of reliability and service life of nuclear power equipment are not only the determination of the main mechanisms of damages and reasons of their appearance, but also the study of methods which would permit to control these properties completely. By giving some examples of Russian NPP equipment with VVER-440 and VVER-1000 reactors the paper presents most typical degradation mechanisms of equipment material properties, including weldments, in the process of operation and methods to recover by using various technological means. (author)

  10. The degradation of nucleotide triphosphates extracted under boiling ethanol conditions is prevented by the yeast cellular matrix.

    Science.gov (United States)

    Gil, Andres; Siegel, David; Bonsing-Vedelaar, Silke; Permentier, Hjalmar; Reijngoud, Dirk-Jan; Dekker, Frank; Bischoff, Rainer

    2017-01-01

    Boiling ethanol extraction is a frequently used method for metabolomics studies of biological samples. However, the stability of several central carbon metabolites, including nucleotide triphosphates, and the influence of the cellular matrix on their degradation have not been addressed. To study how a complex cellular matrix extracted from yeast (Saccharomyces cerevisiae) may affect the degradation profiles of nucleotide triphosphates extracted under boiling ethanol conditions. We present a double-labelling LC-MS approach with a (13)C-labeled yeast cellular extract as complex surrogate matrix, and (13)C(15)N-labeled nucleotides as internal standards, to study the effect of the yeast matrix on the degradation of nucleotide triphosphates. While nucleotide triphosphates were degraded to the corresponding diphosphates in pure solutions, degradation was prevented in the presence of the yeast matrix under typical boiling ethanol extraction conditions. Extraction of biological samples under boiling ethanol extraction conditions that rapidly inactivate enzyme activity are suitable for labile central energy metabolites such as nucleotide triphosphates due to the stabilizing effect of the yeast matrix. The basis of this phenomenon requires further study.

  11. Degradation of BTEX compounds under iron-reducing conditions in contaminated aquifer microcosms

    NARCIS (Netherlands)

    S. Botton; J.R. Parsons

    2006-01-01

    The potential for benzene, toluene, ethylbenzene, and xylenes (BTEX) degradation was investigated in microcosms inoculated with sediment and groundwater from a polluted iron reducing aquifer. Benzene, toluene, and each of the three xylene isomers were degraded by the intrinsic microorganisms under i

  12. Degradation of BTEX compounds under iron-reducing conditions in contaminated aquifer microcosms

    NARCIS (Netherlands)

    Botton, S.; Parsons, J.R.

    2006-01-01

    The potential for benzene, toluene, ethylbenzene, and xylenes (BTEX) degradation was investigated in microcosms inoculated with sediment and groundwater from a polluted iron reducing aquifer. Benzene, toluene, and each of the three xylene isomers were degraded by the intrinsic microorganisms under i

  13. Degradation of herbicides under different redox conditions in eight Danish aquifers

    DEFF Research Database (Denmark)

    Pedersen, Philip Grinder; Mosbæk, Hans; Albrechtsen, Hans-Jørgen

    2000-01-01

    The degradation potential of the herbicides 2,4-D, 2,4,5-T, atrazine, dichlobenil, DNOC, bentazone, DCP (dichloroprop), IPU (isoproturon), MCPA and MCPP (mecoprop) and the degradation product from dichlobenil 2,6-dichlorobenzamide (BAM) were investigated in laboratory incubations with sediment...

  14. Tidal flushing restores the physiological condition of fish residing in degraded salt marshes.

    Science.gov (United States)

    Dibble, Kimberly L; Meyerson, Laura A

    2012-01-01

    Roads, bridges, and dikes constructed across salt marshes can restrict tidal flow, degrade habitat quality for nekton, and facilitate invasion by non-native plants including Phragmites australis. Introduced P. australis contributes to marsh accretion and eliminates marsh surface pools thereby adversely affecting fish by reducing access to intertidal habitats essential for feeding, reproduction, and refuge. Our study assessed the condition of resident fish populations (Fundulus heteroclitus) at four tidally restricted and four tidally restored marshes in New England invaded by P. australis relative to adjacent reference salt marshes. We used physiological and morphological indicators of fish condition, including proximate body composition (% lipid, % lean dry, % water), recent daily growth rate, age class distributions, parasite prevalence, female gravidity status, length-weight regressions, and a common morphological indicator (Fulton's K) to assess impacts to fish health. We detected a significant increase in the quantity of parasites infecting fish in tidally restricted marshes but not in those where tidal flow was restored to reduce P. australis cover. Using fish length as a covariate, we found that unparasitized, non-gravid F. heteroclitus in tidally restricted marshes had significantly reduced lipid reserves and increased lean dry (structural) mass relative to fish residing in reference marshes. Fish in tidally restored marshes were equivalent across all metrics relative to those in reference marshes indicating that habitat quality was restored via increased tidal flushing. Reference marshes adjacent to tidally restored sites contained the highest abundance of young fish (ages 0-1) while tidally restricted marshes contained the lowest. Results indicate that F. heteroclitus residing in physically and hydrologically altered marshes are at a disadvantage relative to fish in reference marshes but the effects can be reversed through ecological restoration.

  15. Tidal flushing restores the physiological condition of fish residing in degraded salt marshes.

    Directory of Open Access Journals (Sweden)

    Kimberly L Dibble

    Full Text Available Roads, bridges, and dikes constructed across salt marshes can restrict tidal flow, degrade habitat quality for nekton, and facilitate invasion by non-native plants including Phragmites australis. Introduced P. australis contributes to marsh accretion and eliminates marsh surface pools thereby adversely affecting fish by reducing access to intertidal habitats essential for feeding, reproduction, and refuge. Our study assessed the condition of resident fish populations (Fundulus heteroclitus at four tidally restricted and four tidally restored marshes in New England invaded by P. australis relative to adjacent reference salt marshes. We used physiological and morphological indicators of fish condition, including proximate body composition (% lipid, % lean dry, % water, recent daily growth rate, age class distributions, parasite prevalence, female gravidity status, length-weight regressions, and a common morphological indicator (Fulton's K to assess impacts to fish health. We detected a significant increase in the quantity of parasites infecting fish in tidally restricted marshes but not in those where tidal flow was restored to reduce P. australis cover. Using fish length as a covariate, we found that unparasitized, non-gravid F. heteroclitus in tidally restricted marshes had significantly reduced lipid reserves and increased lean dry (structural mass relative to fish residing in reference marshes. Fish in tidally restored marshes were equivalent across all metrics relative to those in reference marshes indicating that habitat quality was restored via increased tidal flushing. Reference marshes adjacent to tidally restored sites contained the highest abundance of young fish (ages 0-1 while tidally restricted marshes contained the lowest. Results indicate that F. heteroclitus residing in physically and hydrologically altered marshes are at a disadvantage relative to fish in reference marshes but the effects can be reversed through ecological

  16. Degradation of DEET and Caffeine under UV/Chlorine and Simulated Sunlight/Chlorine Conditions.

    Science.gov (United States)

    Sun, Peizhe; Lee, Wan-Ning; Zhang, Ruochun; Huang, Ching-Hua

    2016-12-20

    Photoactivation of aqueous chlorine could promote degradation of chlorine-resistant and photochemically stable chemicals accumulated in swimming pools. This study investigated the degradation of two such chemicals, N,N-diethyl-3-methylbenzamide (DEET) and caffeine, by low pressure ultraviolet (UV) light and simulated sunlight (SS) activated free chlorine (FC) in different water matrices. Both DEET and caffeine were rapidly degraded by UV/FC and SS/FC but exhibited different kinetic behaviors. The degradation of DEET followed pseudo-first-order kinetics, whereas the degradation of caffeine accelerated with reaction. Mechanistic study revealed that, under UV/FC, ·OH and Cl· were responsible for degradation of DEET, whereas ClO· related reactive species (ClOrrs), generated by the reaction between FC and ·OH/Cl·, played a major role in addition to ·OH and Cl· in degrading caffeine. Reaction rate constants of DEET and caffeine with the respective radical species were estimated. The imidazole moiety of caffeine was critical for the special reactivity with ClOrrs. Water matrix such as pH had a stronger impact on the UV/FC process than the SS/FC process. In saltwater matrix under UV/FC and SS/FC, the degradation of DEET was significantly inhibited, but the degradation of caffeine was much faster than that in nonsalty solutions. The interaction between Br(-) and Cl(-) may play an important role in the degradation of caffeine by UV/FC in saltwater. Reaction product analysis showed similar product patterns by UV/FC and SS/FC and minimal formation of chlorinated intermediates and disinfection byproducts.

  17. Pedestrian evacuation in view and hearing limited condition: The impact of communication and memory

    Science.gov (United States)

    Xue, Shuqi; Jia, Bin; Jiang, Rui; Shan, Jingjing

    2016-09-01

    This paper studies pedestrian evacuation in view and hearing limited condition based on the social force approach. It is assumed that there are two types of pedestrians: Informed individuals know the exit location whereas uninformed individuals do not. The uninformed individuals can communicate with the informed ones within their perceptual fields, thus learning to know and memorize the exit location. We consider cases with and without communication/memory. The simulations show communication and memory are able to enhance the evacuation efficiency. We also investigate the impact of communication on the efficiency of an emergency exit.

  18. A necessary condition for applying MUSIC algorithm in limited-view inverse scattering problem

    Science.gov (United States)

    Park, Taehoon; Park, Won-Kwang

    2015-09-01

    Throughout various results of numerical simulations, it is well-known that MUltiple SIgnal Classification (MUSIC) algorithm can be applied in the limited-view inverse scattering problems. However, the application is somehow heuristic. In this contribution, we identify a necessary condition of MUSIC for imaging of collection of small, perfectly conducting cracks. This is based on the fact that MUSIC imaging functional can be represented as an infinite series of Bessel function of integer order of the first kind. Numerical experiments from noisy synthetic data supports our investigation.

  19. Microbial Degradation of Phenols and Aromatic Hydrocarbons in Creosote-contaminated Groundwater Under Nitrate-reducing Conditions

    DEFF Research Database (Denmark)

    Flyvbjerg, John; Arvin, Erik; Jensen, Bjørn K.

    1993-01-01

    Batch experiments were carried out to investigate the biodegradation of phenols and aromatic hydrocarbons under anaerobic, nitrate-reducing conditions in groundwater from a creosote-contaminated site at Fredensborg, Denmark. The bacteria in the creosote-contaminated groundwater degraded a mixture...

  20. Impact of Charge Degradation on the Life Cycle Climate Performance of a Residential Air-Conditioning System

    Energy Technology Data Exchange (ETDEWEB)

    Beshr, Mohamed [University of Maryland, College Park; Aute, Vikrant [University of Maryland, College Park; Abdelaziz, Omar [ORNL; Fricke, Brian A [ORNL; Radermacher, Reinhard [University of Maryland, College Park

    2014-01-01

    Vapor compression systems continuously leak a small fraction of their refrigerant charge to the environment, whether during operation or servicing. As a result of the slow leak rate occurring during operation, the refrigerant charge decreases until the system is serviced and recharged. This charge degradation, after a certain limit, begins to have a detrimental effect on system capacity, energy consumption, and coefficient of performance (COP). This paper presents a literature review and a summary of previous experimental work on the effect of undercharging or charge degradation of different vapor compression systems, especially those without a receiver. These systems include residential air conditioning and heat pump systems utilizing different components and refrigerants, and water chiller systems. Most of these studies show similar trends for the effect of charge degradation on system performance. However, it is found that although much experimental work exists on the effect of charge degradation on system performance, no correlation or comparison between charge degradation and system performance yet exists. Thus, based on the literature review, three different correlations that characterize the effect of charge on system capacity and energy consumption are developed for different systems as follows: one for air-conditioning systems, one for vapor compression water-to-water chiller systems, and one for heat pumps. These correlations can be implemented in vapor compression cycle simulation tools to obtain a better prediction of the system performance throughout its lifetime. In this paper, these correlations are implemented in an open source tool for life cycle climate performance (LCCP) based design of vapor compression systems. The LCCP of a residential air-source heat pump is evaluated using the tool and the effect of charge degradation on the results is studied. The heat pump is simulated using a validated component-based vapor compression system model and

  1. Conditions Optimizing and Application of Laccase-mediator System (LMS) for the Laccase-catalyzed Pesticide Degradation

    Science.gov (United States)

    Jin, Xiaoting; Yu, Xiangyang; Zhu, Guangyan; Zheng, Zuntao; Feng, Fayun; Zhang, Zhiyong

    2016-01-01

    A high capacity of laccase from Trametes versicolor capable of degrading pesticides has been revealed. The conditions for degrading of five selected pesticides including chlorpyrifos, chlorothalonil, pyrimethanil, atrazine and isoproturon with the purified laccases from Trametes versicolor were optimized. The results showed that the optimum conditions for the highest activity were pH at 5.0 and temperature at 25 °C. The best mediators were violuric acid for pyrimethanil and isoproturon, vanillin for chlorpyrifos, and acetosyringone and HBT for chlorothalonil and atrazine, respectively. The laccase was found to be stable at a pH range from 5.0 to 7.0 and temperature from 25 to 30 °C. It was observed that each pesticide required a different laccase mediator concentration typically between 4.0–6.0 mmol/L. In the experiment, the degradation rates of pyrimethanil and isoproturon were significantly faster than those of chlorpyrifos, chlorothalonil and atrazine. For example, it was observed that pyrimethanil and isoproturon degraded up to nearly 100% after 24 hours while the other three pesticides just reached up 90% of degradation after 8 days of incubation. PMID:27775052

  2. Degradation pathway of 2-chloroethanol in Pseudomonas stutzeri strain JJ under denitrifying conditions

    NARCIS (Netherlands)

    Dijk, J.A.; Gerritse, J.; Schraa, G.; Stams, A.J.M.

    2004-01-01

    The pathway of 2-chloroethanol degradation in the denitrifying Pseudomonas stutzeri strain JJ was investigated. In cell-free extracts, activities of a phenazine methosulfate (PMS)-dependent chloroethanol dehydrogenase, an NAD-dependent chloroacetaldehyde dehydrogenase, and a chloroacetate dehalogena

  3. Model-based analysis of photoinitiated coating degradation under artificial exposure conditions

    DEFF Research Database (Denmark)

    Kiil, Søren

    2012-01-01

    Coating degradation mechanisms of thermoset coatings exposed to ultraviolet radiation and humidity at constant temperature are investigated. The essential processes, photoinitiated oxidation reactions, intrafilm oxygen permeability, water absorption and diffusion, reduction of crosslink density...

  4. Augmenting atrazine and hexachlorobenzene degradation under different soil redox conditions in a bioelectrochemistry system and an analysis of the relevant microorganisms.

    Science.gov (United States)

    Wang, Hui; Cao, Xian; Li, Lei; Fang, Zhou; Li, Xianning

    2017-09-20

    Soil microbial fuel cells (MFCs) are a sustainable technology that degrades organic pollutants while generating electricity. However, there have been no detailed studies of the mechanisms of pollutant degradation in soil MFCs. In this study, the effects of external resistance and electrode effectiveness on atrazine and hexachlorobenzene (HCB) degradation were evaluated, the performance of soil MFCs in the degradation of these pollutants under different soil redox conditions was assessed, and the associated microorganisms in the anode were investigated. With an external resistance of 20Ω, the degradation efficiencies of atrazine and HCB were 95% and 78%, respectively. The degradation efficiency, degradation rate increased with decreasing external resistance, while the half-life decreased. There were different degradation trends for different pollutants under different soil redox conditions. The fastest degradation rate of atrazine was in the upper MFC section (aerobic), whereas that of HCB was in the lower MFC section (anaerobic). The results showed that electrode effectiveness played a significant role in pollution degradation. In addition, the microbial community analysis demonstrated that Proteobacteria, especially Deltaproteobacteria involved in current generation was extremely abundant (27.49%) on soil MFC anodes, although the percentage abundances of atrazine degrading Rhodocyclaceae (8.77%), Desulfitobacterium (0.64%), and HCB degrading Desulfuromonas (0.73%), were considerably lower. The results of the study suggested that soil MFCs can enhance the degradation of atrazine and HCB, and bioelectrochemical reduction was the main mechanism for the pollutants degradation. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. A qualitative study of stakeholder views of the conditions for and outcomes of successful clinical networks

    Directory of Open Access Journals (Sweden)

    McInnes Elizabeth

    2012-02-01

    Full Text Available Abstract Background Clinical networks have been established to improve health outcomes and processes of care by implementing a range of innovations and undertaking projects based on perceived local need. Limited research exists on the necessary conditions required to bring about successful network outcomes and what characterises network success from the perspective of those involved in network initiatives. This qualitative study identified stakeholder views on i the conditions for effective clinical networks; and ii desirable outcomes of successful clinical networks. Methods Twenty-seven participants were interviewed using face-to-face audio-recorded semi-structured interviews. Transcribed data were coded and analysed to generate themes relating to the study aims. Results Five key factors represented as sub-themes were identified as important conditions for the establishment of successful clinical networks under the main theme of effective network structure, organisation and governance. These were: building relationships; effective leadership; strategic evidence-based workplans; adequate resources; and ability to implement and evaluate network initiatives. Two major themes encapsulated views on desirable outcomes of successful clinical networks: connecting and engaging which represented the outcomes of interdisciplinary and consumer collaboration and, partnerships with state health and local health services, and changing the landscape of care, which represented the importance of outcomes associated with improving services, care and patient health outcomes and implementing evidence-based practice. Conclusions This study provides new knowledge on the conditions needed to establish successful clinical networks and on desirable outcomes arising from network projects and initiatives that are considered to be valuable by those working in or associated with clinical networks. This provides health services with information on what needs to be in place

  6. Accelerated Degradation Test and Predictive Failure Analysis of B10 Copper-Nickel Alloy under Marine Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Bo Sun

    2015-09-01

    Full Text Available This paper studies the corrosion behavior of B10 copper-nickel alloy in marine environment. Accelerated degradation test under marine environmental conditions was designed and performed based on the accelerated testing principle and the corrosion degradation mechanism. With the prolongation of marine corrosion time, the thickness of Cu2O film increased gradually. Its corrosion product was Cu2(OH3Cl, which increased in quantity over time. Cl− was the major factor responsible for the marine corrosion of copper and copper alloy. Through the nonlinear fitting of corrosion rate and corrosion quantity (corrosion weight loss, degradation data of different corrosion cycles, the quantitative effects of two major factors, i.e., dissolved oxygen (DO and corrosion medium temperature, on corrosion behavior of copper alloy were analyzed. The corrosion failure prediction models under different ambient conditions were built. One-day corrosion weight loss under oxygenated stirring conditions was equivalent to 1.31-day weight loss under stationary conditions, and the corrosion rate under oxygenated conditions was 1.31 times higher than that under stationary conditions. In addition, corrosion medium temperature had a significant effect on the corrosion of B10 copper sheet.

  7. Dynamic spatiotemporal brain analyses of the visual checkerboard task: Similarities and differences between passive and active viewing conditions.

    Science.gov (United States)

    Cacioppo, Stephanie; Weiss, Robin M; Cacioppo, John T

    2016-10-01

    We introduce a new analytic technique for the microsegmentation of high-density EEG to identify the discrete brain microstates evoked by the visual reversal checkerboard task. To test the sensitivity of the present analytic approach to differences in evoked brain microstates across experimental conditions, subjects were instructed to (a) passively view the reversals of the checkerboard (passive viewing condition), or (b) actively search for a target stimulus that may appear at the fixation point, and they were offered a monetary reward if they correctly detected the stimulus (active viewing condition). Results revealed that, within the first 168 ms of a checkerboard presentation, the same four brain microstates were evoked in the passive and active viewing conditions, whereas the brain microstates evoked after 168 ms differed between these two conditions, with more brain microstates elicited in the active than in the passive viewing condition. Additionally, distinctions were found in the active condition between a change in a scalp configuration that reflects a change in microstate and a change in scalp configuration that reflects a change in the level of activation of the same microstate. Finally, the bootstrapping procedure identified that two microstates lacked robustness even though statistical significance thresholds were met, suggesting these microstates should be replicated prior to placing weight on their generalizability across individuals. These results illustrate the utility of the analytic approach and provide new information about the spatiotemporal dynamics of the brain states underlying passive and active viewing in the visual checkerboard task. © 2016 Society for Psychophysiological Research.

  8. Reorganization of gene network for degradation of polycyclic aromatic hydrocarbons (PAHs) in Pseudomonas aeruginosa PAO1 under several conditions.

    Science.gov (United States)

    Yan, Shaomin; Wu, Guang

    2017-07-07

    Although polycyclic aromatic hydrocarbons (PAHs) are harmful to human health, their elimination from the environment is not easy. Biodegradation of PAHs is promising since many bacteria have the ability to use hydrocarbons as their sole carbon and energy sources for growth. Of various microorganisms that can degrade PAHs, Pseudomonas aeruginosa is particularly important, not only because it causes a series of diseases including infection in cystic fibrosis patients, but also because it is a model bacterium in various studies. The genes that are responsible for degrading PAHs have been identified in P. aeruginosa, however, no gene acts alone as various stresses often initiate different metabolic pathways, quorum sensing, biofilm formation, antibiotic tolerance, etc. Therefore, it is important to study how PAH degradation genes behave under different conditions. In this study, we apply network analysis to investigating how 46 PAH degradation genes reorganized among 5549 genes in P. aeruginosa PAO1 under nine different conditions using publicly available gene coexpression data from GEO. The results provide six aspects of novelties: (i) comparing the number of gene clusters before and after stresses, (ii) comparing the membership in each gene cluster before and after stresses, (iii) defining which gene changed its membership together with PAH degradation genes before and after stresses, (iv) classifying membership-changed-genes in terms of category in Pseudomonas Genome Database, (v) postulating unknown gene's function, and (vi) proposing new mechanisms for genes of interests. This study can shed light on understanding of cooperative mechanisms of PAH degradation from the level of entire genes in an organism, and paves the way to conduct the similar studies on other genes.

  9. Assessment of the ability of sludge to degrade PCP under anaerobic conditions

    Directory of Open Access Journals (Sweden)

    R. M. L. Bolaños

    2005-12-01

    Full Text Available The capacity of sludge from different sources to degrade pentachlorophenol (PCP was evaluated. Three 2.5 liter reactors (R1, R2, and R3 were inoculated with different anaerobic sludges, semi continuously fed and maintained in orbital motion at 30±1°C. R1 was inoculated with aerobic sludge and river sediment collected downstream from a pulp and paper plant. R2 received sludge from an anaerobic reactor treating effluents from a paper recycling plant and R3 received anaerobic sludge from a biodigestor treating industrial and domestic effluents. The sludges were first acclimatized to a culture medium generally recommended for organochloride anaerobic degradation studies. The reactors were then subjected to increasing concentrations of PCP from 0.05 to 10.0 mg.l-1. PCP degradation and metabolite formation were monitored using gas chromatography, and the effects of PCP on the anaerobic process were verified by monitoring pH, volatile fatty acids, alkalinity, total suspended solids, and chemical oxygen demand. It was found that PCP did not affect reactor performance. All the sludges displayed the best PCP degradation capacity at a concentration of 0.2 mg.l-1, producing fewer chlorinated metabolites than when higher PCP concentrations were applied. R1 consistently produced fewer chlorinated metabolites, confirming the hypothesis that pre exposure to chlorinated compounds improves the sludge's capacity to degrade PCP.

  10. Anaerobic BTEX degradation in soil bioaugmented with mixed consortia under nitrate reducing conditions

    Institute of Scientific and Technical Information of China (English)

    DOU Junfeng; LIU Xiang; HU Zhifeng

    2008-01-01

    Different concentrations of BTEX, including benzene, toluene, ethylbenzene, and three xylene isomers, were added into soil samples to investigate the anaerobic degradation potential by the augmented BTEX-adapted consortia under niwate reducing conditiom. All the BTEX substrates could be anaerobically biodegraded to non-detectable levels within 70 d when the initial concentrations were below 100 mg/kg in soil. Toluene was degraded faster than any other BTEX compounds, and the high-to-low order ofdegradation rates were toluene>ethylbenzene>m. xylene>o-xylene>benzene>P. xylene. Nitrite was accumulated with nitrate reduction. but the accumulation of nitrite had no inhibitory effect on the degradation of BTEX throughout the whole incubation. Indigenous bacteria in tIle soil could enhance the BTEX biodegradation ability of the enriched mixed bacteria. When the six BTEX compounds were simultaneously present in soil, there was no apparent inhibitory effect on their degradation with lower initial concentrations. Alternatively, benzene, o-xylene, and P-xylene degradation were inhibited with higher initial concentrations of 300 mg/kg. Higher BTEX biodegradation rates were observed in soil samples with the addition of sodium acetate compared to the presence of a single BTEX substrate. and the hypothesis of primary-substrate stimulation or cometabolic enhancement of BTEX biodegradation seems likely.

  11. Hydrolysis and degradation of filtrated organic particulates in a biofilm reactor under anoxic and aerobic conditions

    DEFF Research Database (Denmark)

    Janning, K.F.; Mesterton, K.; Harremoës, P.

    1997-01-01

    carbon to the bulk liquid was observed as an indication of hydrolysis taking place. The second experiment was designed as a series of on-line OUR batch experiments in a biofilm reactor with recirculation, in order to investigate further the degradation of particulate organic matter. After the biofilm had...... been starved in order to remove the original organic matter, particulate organic matter was added and the degradation kinetics recorded. The initial removal rate was high, r(A.O2) = 2.1 g O-2/(m(2)d) though fast declining towards endogenous respiration. The respiration ratio between removed oxygen...... and produced carbon dioxide was declining from 1.3 to 1.0 g O-2/g CO2 during the degradation of organic particulates. The respiration ratio during endogenous respiration was determined to be 0.7 g O-2/g CO2 indicating a thorough mineralisation of biomass. (C) 1997 IAWQ. Published by Elsevier Science Ltd....

  12. Electrochemical performance of nickel/metal hydride batteries under unconventional conditions and degradation analysis

    Institute of Scientific and Technical Information of China (English)

    李丽; 吴锋; 杨凯; 王敬; 陈实

    2004-01-01

    The charge-discharge performance and cycle stability of D size Ni/MH batteries at -20 ℃, 25 ℃ and 55℃ were examined. The results show that the decline rate of Ni/MH battery discharge capacity at -20 ℃ and 55 ℃ are 12.1% and 13.6% ,and the average discharge voltage decreases by a value of 0.13 V and 0.06 V respectively,cycling stability declines obviously at various temperatures. The capacity degradation of Ni/MH batteries under low temperature is reversible, belonging to transient degradation and that of high and normal temperatures are not reversible, belonging to permanent degradation. Electrochemical impedance spectroscopy, scanning electron microscope and energy dispersive X-ray analyzer were introduced to study the main causes of cycling deterioration of Ni/MH batteries.

  13. Early development of dynamic shape perception under slit-viewing conditions.

    Science.gov (United States)

    Imura, Tomoko; Shirai, Nobu

    2014-01-01

    The developmental processes underpinning global shape and global motion perception in infancy have been relatively well described. However, the development of the ability to integrate both global motion and global shape information has remained unclear. In this study we employed a slit-viewing task to investigate the ability to integrate spatiotemporal information among infants ranging in age from 3 to 12 months. In experiment 1 each infant was familiarised with a moving object that was only partly visible through a slit. One of the two objects in the test trial was a novel object, and the other object had appeared previously in familiarisation trials. The findings suggested that infants aged 5 months and over looked longer at the novel drawings compared with the more familiar objects in the test trials. This implies that the infants recognised the whole shape of the object under the slit-viewing condition. In experiment 2 each infant was presented with partial images in a random order. In this case the infants were unable to distinguish the whole shape of the object. The findings suggest that infants did not rely on the local cues provided in experiment .

  14. Examination of dioxin degradation conditions for geobacillus midousuji SH2B-J2

    Energy Technology Data Exchange (ETDEWEB)

    Hoshina, S. [Jikei Univ., School of Medicine, Tokyo (Japan); Ohtsuka, Y. [Forestry and Forest Products Research Instiute; Goda, H. [Towa Kagaku Co., Ltd.

    2004-09-15

    Cellular membrane degradation capability of SH2B-J2 strains for dioxin mixtures that are greater than tetra-chlorinated have been examined. Optimal temperature, reaction time, optimal pH, and heavy metal resistance of cellular membrane enzyme were investigated, to examine dioxin degradation characteristics of SH2B-J2 strains. For chlorinated dioxins, a mixture (PCDD/PCDF mix) containing 7 species of dibenzo-p-dioxins greater than tetra-chlorinated, as well as 10 isomers of dibenzofurans, was used. Using GC/MS, decrease of 17 species of dioxin isomer/congener was measured.

  15. Role of active oxidative species on TiO2 photocatalysis of tetracycline and optimization of photocatalytic degradation conditions.

    Science.gov (United States)

    Luo, Zhaohui; Li, Lu; Wei, Chuanlin; Li, Huixin; Chen, Dan

    2015-07-01

    The optimum operating conditions for TiO2 photocatalytic degradation of tetracycline antibiotic (TC) in aqueous solution and the role of active oxidative species (AOS) from UV/TiO2 in its degradation were investigated. Response surface methodology (RSM) and central composite design (CCD) were adopted to optimize three parameters: TiO2 concentration, initial pH and UV irradiation time. Radical scavengers were added to reaction solution to assess the photocatalytic reaction mechanism of TC. The results showed that 93.1% degradation efficiency was obtained under optimum conditions established during experimentation (TiO2 concentration = 2.09 g l(-1), pH = 5.56 and t = 20.95 min). These results agree with the prediction made by the proposed model. Photocatalytic degradation of TC followed a pseudo first-order reaction rate. Photogenerated holes (h+(VB)) with minor participation from superoxide anions (O2*), were responsible for TC oxidation on TiO2, while hydroxyl radicals (*OH) played a negligible role in titania-TC oxidation.

  16. 油脂降解菌种的鉴定及降解条件优化%Identification of Oil Degradable Bacterial Strain & Optimization of Degradation Condition

    Institute of Scientific and Technical Information of China (English)

    张印; 薛永常

    2015-01-01

    从学校食堂排放的废水中筛选出1株油脂降解菌株,经形态特征、生理生化特征、16S rDNA 同源性序列分析,鉴定为克雷伯氏菌属,暂命名为 Klebsiella sp. X-1。并利用正交实验进一步考察了 pH、培养温度、摇床转速对油脂降解率的影响。实验结果表明,在高含油废水培养基中,pH 7.0、转速为140 r/ min、培养温度为30℃时,72 h 内该菌的油脂降解率最高达68.2%。%An oil degradable bacterial strain was screened from wastewater discharged from the university dining hall. It was identified as Klebsiella sp. X-1 through its morphological,physiological and biochemical features,and 16S rDNA homology sequencing analysis. The effects of pH,temperature,and shaking rpm on oil degradation were further observed adopted with orthogonal experiment. The results showed that within 72 hours,in the high oily wastewater me-dium,the optimum process conditions were as follows:pH 7,shaking at 140 r/ min,cultured at 30 ℃,the oil de-gradable rate of the strain reached at the highest of 68. 2% .

  17. Storage and degradation of poly-ß-hydroxybutyrate in activated sludge under aerobic conditions

    DEFF Research Database (Denmark)

    Dircks, Klaus; Henze, Mogens; van Loosdrecht, M.C.M.

    2001-01-01

    This research analyses the accumulation and degradation of poly-b-hydroxybutyrate (PHB) in experiments with pulse addition of acetate to samples of activated sludge from pilot-plant and full-scale wastewater treatment plants. The experiments are divided into two periods: a feast period defined...

  18. DEGRADATION OF POLYNUCLEAR AROMATIC HYDROCARBONS UNDER BENCH-SCALE COMPOST CONDITIONS

    Science.gov (United States)

    The relationship between biomass growth and degradation of polynuclear aromatic hydrocarbons (PAHs) in soil, and subsequent toxicity reduction, was evaluated in 10 in-vessel, bench-scale compost units. Field soil was aquired from the Reilly Tar and Chemical Company Superfund site...

  19. Extensions to modeling aerobic carbon degradation using combined respirometric-titrimetric measurements in view of activated sludge model calibration.

    Science.gov (United States)

    Sin, Gürkan; Vanrolleghem, Peter A

    2007-08-01

    Recently a model was introduced to interpret the respirometric (OUR) -titrimetric (Hp) data obtained from aerobic oxidation of different carbon sources in view of calibration of Activated Sludge Model No.1 (ASM1). The model requires, among others, the carbon dioxide transfer rate (CTR) to be relatively constant during aerobic experiments. As CTR is an inherently nonlinear process, this assumption may not hold for certain experimental conditions. Hence, we extended the model to describe the nonlinear CTR behavior. A simple calibration procedure of the CO2 model was developed only using titrimetric data. The identifiable parameter subset of this model when using titrimetric data only contained the first equilibrium constant of the CO2 dissociation, pK1, the initial aqueous CO2 concentration, C(Tinit) and the nitrogen content of biomass, i(NBM). The extended model was then successfully applied to interpret typical data obtained from respirometric-titrimetric measurements with a nonlinear CO2 stripping process. The parameter estimation results using titrimetric data were consistent with the results estimated using respirometric data (OUR) alone or combined OUR and Hp data, thereby supporting the validity of the dynamic CO2 model and its calibration approach. The increased range of applicability and accurate utilization of the titrimetric data are expected to contribute particularly to the improvement of calibration of ASM models using batch experiments.

  20. Characteristics of phenol degradation in saline conditions of a halophilic strain JS3 isolated from industrial activated sludge.

    Science.gov (United States)

    Jiang, Yu; Yang, Kai; Wang, Hongyu; Shang, Yu; Yang, Xiaojun

    2015-10-15

    Several halophilic bacteria have been reported to degrade phenol. However, there are a few works about salt-tolerant fungi which can utilize phenol as sole source of carbon. In this study, a halophilic strain JS3 which could degrade phenol with high efficiency was separated and identified. The effect of initial phenol concentration on phenol biodegradation was investigated and optimal pH, temperature, as well as salt-tolerance were evaluated. The isolate could degrade less than 800 mg/L phenol completely in 72 h. It grew well when pH, temperature, and salinity were at values of 4.0-9.0, 30-40°C, and 0-7%, respectively. The optimal pH, temperature and salinity were 6.0, 35°C and 0%. More than 99% of 500 mg/L phenol was degraded in the optimal condition within 24h. The tolerance of wide range of pH, temperature and salinity indicated that strain JS3 was effective for phenol removal in hypersaline wastewaters.

  1. Novel extracellular PHB depolymerase from Streptomyces ascomycinicus: PHB copolymers degradation in acidic conditions.

    Directory of Open Access Journals (Sweden)

    Javier García-Hidalgo

    Full Text Available The ascomycin-producer strain Streptomyces ascomycinicus has been proven to be an extracellular poly(R-3-hydroxybutyrate (PHB degrader. The fkbU gene, encoding a PHB depolymerase (PhaZ Sa , has been cloned in E. coli and Rhodococcus sp. T104 strains for gene expression. Gram-positive host Rhodococcus sp. T104 was able to produce and secrete to the extracellular medium an active protein form. PhaZ Sa was purified by two hydrophobic interaction chromatographic steps, and afterwards was biochemically as well as structurally characterized. The enzyme was found to be a monomer with a molecular mass of 48.4 kDa, and displayed highest activity at 45°C and pH 6, thus being the first PHB depolymerase from a gram-positive bacterium presenting an acidic pH optimum. The PHB depolymerase activity of PhaZ Sa was increased in the presence of divalent cations due to non-essential activation, and also in the presence of methyl-β-cyclodextrin and PEG 3350. Protein structure was analyzed, revealing a globular shape with an alpha-beta hydrolase fold. The amino acids comprising the catalytic triad, Ser(131-Asp(209-His(269, were identified by multiple sequence alignment, chemical modification of amino acids and site-directed mutagenesis. These structural results supported the proposal of a three-dimensional model for this depolymerase. PhaZ Sa was able to degrade PHB, but also demonstrated its ability to degrade films made of PHB, PHBV copolymers and a blend of PHB and starch (7∶3 proportion wt/wt. The features shown by PhaZ Sa make it an interesting candidate for industrial applications involving PHB degradation.

  2. Enhanced degradation of atrazine under field conditions correlates with a loss of weed control in the glasshouse.

    Science.gov (United States)

    Krutz, L Jason; Zablotowicz, Robert M; Reddy, Krishna N; Koger, Clifford H; Weaver, Mark A

    2007-01-01

    Enhanced degradation of atrazine has been reported in the literature, indicating the potential for reduced residual weed control with this herbicide. Experiments were conducted to determine the field dissipation of atrazine in three cropping systems: continuous Zea mays L. (CC) receiving atrazine applications each year, Gossypium hirsutum L.-Z. mays rotation (CCR) receiving applications of atrazine once every 2 years and a no atrazine history soil (NAH). Subsequent laboratory and greenhouse experiments were conducted with soil collected from these cropping systems to determine atrazine degradation, mineralization and residual weed control. Field dissipation of atrazine followed first-order kinetics, and calculated half-life values for atrazine combined over 2003 and 2005 increased in the order of CC (9 d) = CCR (10 d) atrazine was approximately twofold greater in NAH soil than in CC or CCR soil. Biometer flask mineralization studies suggested that enhanced degradation of atrazine was due to rapid catabolism of the s-triazine ring. Glasshouse efficacy studies revealed a loss of residual weed control in CC and CCR soil compared with NAH soil. These data indicate that, under typical Mississippi Delta field conditions and agronomic practices, the persistence of atrazine may be reduced by at least 50% if the herbicide is applied more than once every 24 months. Glasshouse studies suggest that under these conditions a loss of residual weed control is possible.

  3. Degradation of H3PO4/PBI High Temperature Polymer Electrolyte Membrane Fuel Cell under Stressed Operating Conditions

    DEFF Research Database (Denmark)

    Zhou, Fan

    for HT-PEM fuel cell based micro-CHP units for households, the daily startup/shutdown operation is necessary. Moreover, the faults in the H2 supply system or in controlling the reformer can cause the H2 starvation of the HT-PEM fuel cell. The effects of these operating conditions to the degradation...... of the HT-PEM fuel cell are studied in the current work. Both in-situ and ex-situ characterization techniques are conducted to gain insight into the degradation mechanisms of the HT-PEM fuel cell under these operating conditions. The experimental results in this work suggest that the presence of methanol...... results in the degradation in cell performance of the HT-PEM fuel cell by increasing the charge transfer resistance and mass transfer resistance. The CO with volume fraction of 1% – 3% can cause significant performance loss to the HT-PEM fuel cell at the operating temperature of 150 oC. The cell...

  4. Remote sensing of forest degradation in Southeast Asia—Aiming for a regional view through 5–30 m satellite data

    Directory of Open Access Journals (Sweden)

    Jukka Miettinen

    2014-12-01

    Full Text Available In this review paper we present geographical, ecological and historical aspects of Southeast Asia from the perspective of forest degradation monitoring and critically discuss available approaches for large area forest degradation monitoring with satellite remote sensing data at high to medium spatial resolution (5–30 m. Several authors have achieved promising results in geographically limited areas within Southeast Asia using automated detection algorithms. However, the application of automated methods to large area assessments remains a major challenge. To-date, nearly all large area assessments of forest degradation in the region have included a strong visual interpretation component. We conclude that due to the variety of forest types and forest disturbance levels, as well as the variable image acquisition conditions in Southeast Asia, it is unlikely that forest degradation monitoring can be conducted throughout the region using a single automated approach with currently available remote sensing data. The provision of regionally consistent information on forest degradation from satellite remote sensing data remains therefore challenging. However, the expected increase in observation frequency in the near future (due to Landsat 8 and Sentinel-2 satellites may lead to the desired improvement in data availability and enable consistent and robust regional forest degradation monitoring in Southeast Asia.

  5. SENP2 negatively regulates cellular antiviral response by deSUMOylating IRF3 and conditioning it for ubiquitination and degradation

    Institute of Scientific and Technical Information of China (English)

    Yong Ran; Tian-Tian Liu; Qian Zhou; Shu Li; Ai-Ping Mao; Ying Li; Li-Juan Liu; Jin-Ke Cheng; Hong-Bing Shu

    2011-01-01

    Transcription factor IRF3-mediated type I interferon induction is essential for antiviral innate immunity.We identified the deSUMOylating enzyme Sentrin/SUMO-specific protease (SENP) 2 as a negative regulator of virus-triggered IFN-β induction.Overexpression of SENP2 caused IRF3 deSUMOylation,K48-linked ubiquitination,and degradation,whereas depletion of SENP2 had opposite effects.Both the SUMOylation and K48-linked ubiquitination of IRF3 occurred at iysines 70 and 87,and these processes are competitive.The level of virus-triggered IFN-β was markedly up-regulated and viral replication was reduced in SENP2-deficient cells comparing with wild-type controls.Our findings suggest that SENP2 regulates antiviral innate immunity by deSUMOylating IRF3 and conditioning it for ubiquitination and degradation,and provide an example of cross-talk between the ubiquitin and SUMO pathways in innate immunity.%Transcription factor IRF3-mediated type I interferon induction is essential for antiviral innate immunity. We identified the deSUMOylating enzyme Sentrin/SUMO-specific protease (SENP) 2 as a negative regulator of virus-triggered IFN-p induction. Overexpression of SENP2 caused IRF3 deSUMOylation, K48-linked ubiquitination, and degradation, whereas depletion of SENP2 had opposite effects. Both the SUMOylation and K48-linked ubiquitination of IRF3 occurred at lysines 70 and 87, and these processes are competitive. The level of virus-triggered IFN-β was markedly up-regulated and viral replication was reduced in SENP2-deficient cells comparing with wild-type controls. Our findings suggest that SENP2 regulates antiviral innate immunity by deSUMOylating IRF3 and conditioning it for ubiquitination and degradation, and provide an example of cross-talk between the ubiquitin and SUMO pathways in innate immunity.

  6. Effects of operational conditions on sludge degradation and organic acids formation in low-critical wet air oxidation.

    Science.gov (United States)

    Chung, Jinwook; Lee, Mikyung; Ahn, Jaehwan; Bae, Wookeun; Lee, Yong-Woo; Shim, Hojae

    2009-02-15

    Wet air oxidation processes are to treat highly concentrated organic compounds including refractory materials, sludge, and night soil, and usually operated at supercritical water conditions of high temperature and pressure. In this study, the effects of operational conditions including temperature, pressure, and oxidant dose on sludge degradation and conversion into subsequent intermediates such as organic acids were investigated at low critical wet oxidation conditions. The reaction time and temperature in the wet air oxidation process was shown an important factor affecting the liquefaction of volatile solids, with more significant effect on the thermal hydrolysis reaction rather than the oxidation reaction. The degradation efficiency of sludge and the formation of organic acids were improved with longer reaction time and higher reaction temperature. For the sludge reduction and the organic acids formation under the wet air oxidation, the optimal conditions for reaction temperature, time, pressure, and oxidant dose were shown approximately 240 degrees C, 30min, 60atm, and 2.0L/min, respectively.

  7. Northern Islands, human error, and environmental degradation: A view of social and ecological change in the medieval North Atlantic

    Energy Technology Data Exchange (ETDEWEB)

    McGovern, T.H.; Bigelow, G.; Amorosi, T.; Russell, D. (City Univ. of New York, NY (USA))

    1988-09-01

    Between ca. 790 and 1,000 AD, Scandinavian settlers occupied the islands of the North Atlantic: Shetland, the Orkneys, the Hebrides, the Faroes, Iceland, and Greenland. These offshore islands initially supported stands of willow, alder, and birch, and a range of non-arboreal species suitable for pasture for the imported Norse domestic animals. Overstocking of domestic animals, fuel collection, ironworking, and construction activity seems to have rapidly depleted the dwarf trees, and several scholars argue that soil erosion and other forms of environmental degradation also resulted from Norse land-use practices in the region. Such degradation of pasture communities may have played a significant role in changing social relationships and late medieval economic decline in the western tier colonies of Iceland and Greenland. This paper presents simple quantified models for Scandinavian environmental impact in the region, and suggests some sociopolitical causes for ultimately maladaptive floral degradation.

  8. Degradation of carbon-based materials under ablative conditions produced by a high enthalpy plasma jet

    Directory of Open Access Journals (Sweden)

    Gilberto Petraconi

    2010-04-01

    Full Text Available A stationary experiment was performed to study the degradation of carbon-based materials by immersion in a plasma jet. In the experiment, graphite and C/C composite were chosen as the target materials, and the reactive plasma jet was generated by an air plasma torch. For macroscopic study of the material degradation, the sample’s mass losses were measured as function of the exposure time under various temperatures on the sample surface. A microscopic analysis was then carried out for the study of microscopic aspects of the erosion of material surface. These experiments showed that the mass loss per unit area is approximately proportional to the exposure time and strongly depends on the temperature of the material surface. The mass erosion rate of graphite was appreciably higher than the C/C composite. The ablation rate in the carbon matrix region in C/C composite was also noticeably higher than that in the fiber region. In addition, the latter varied according to the orientation of fibers relatively to the flow direction. These tests indicated an excellent ablation resistance of the C/C composite, thus being a reliable material for rocket nozzles and heat shielding elements of the protection systems of hypersonic apparatuses from aerodynamic heating.

  9. Evidence of CFC degradation in groundwater under pyrite-oxidizing conditions

    Science.gov (United States)

    Sebol, L.A.; Robertson, W.D.; Busenberg, E.; Plummer, L.N.; Ryan, M.C.; Schiff, S.L.

    2007-01-01

    A detailed local-scale monitoring network was used to assess CFC distribution in an unconfined sand aquifer in southwestern Ontario where the zone of 1-5-year-old groundwater was known with certainty because of prior use of a bromide tracer. Groundwater ???5 years old was confined to an aerobic zone at ???5 m depth and had CFC concentrations consistent with modern atmospheric mixing ratios at recharge temperatures of 7-11 ??C, as was observed in the 3-m thick vadose zone at the site. At depths below 6 m, the groundwater became progressively more reducing, however, with a denitrifying horizon at 6-7 m depth, and a Mn and Fe reducing zone below 7 m depth. In the anaerobic zone, 3H/3He ratios indicated that groundwater-age continued to increase uniformly with depth, to a maximum value of 27 years at 13 m depth. CFC concentrations, however, decreased abruptly within the denitrifying zone, leading to substantial age overestimation compared to the 3H/3He ages. Noble gas data indicated that the apparent CFC mass loss was not likely the result of gas stripping from possible bubble formation; thus, CFC degradation was indicated in the anoxic zone. The field data are consistent with first-order degradation rates of 0.3 yr-1 for CFC-12, 0.7 yr-1 for CFC-11, and 1.6 yr-1 for CFC-113. CFC attenuation at this site coincides with a zone where reduced S (pyrite) is actively oxidized by NO3 and dissolved oxygen (DO). Similar behavior has been observed at other sites [Tesoriero, A.J., Liebscher, H., Cox, S.E., 2000. Mechanism and rate of denitrification in an agricultural watershed: electron and mass balance along groundwater flow path. Water Resour. Res. 36 (6), 1545-1559; Hinsby, K., Hojberg, A.L., Engesgaard, P., Jensen, K.H., Larsen, F., Plummer, L.N., Busenberg, E., Accepted for publication. Transport and degradation of chlorofluorocarbons (CFCs) in a pyritic aquifer, Rabis Creek, Denmark. Water Resour. Res.], further demonstrating that the use of CFCs for age-dating anaerobic

  10. The use of the fungus Dichomitus squalens for degradation in rotating biological contactor conditions.

    Science.gov (United States)

    Novotný, Ceněk; Trošt, Nina; Šlušla, Martin; Svobodová, Kateřina; Mikesková, Hana; Válková, Hana; Malachová, Kateřina; Pavko, Aleksander

    2012-06-01

    Biodegradation potential of Dichomitus squalens in biofilm cultures and rotating biological contactor (RBC) was investigated. The fungus formed thick biofilms on inert and lignocellulosic supports and exhibited stable activities of laccase and manganese peroxidase to reach 40-62 and 25-32% decolorization of anthraquinone Remazol Brilliant Blue R and heterocyclic phthalocyanine dyes, respectively. The decolorization ceased when glucose concentration dropped to 1 mmol l(-1). In RBC reactor, respective decolorizations of Remazol Brilliant Blue R and heterocyclic Methylene Blue and Azure B dyes (50 mg l(-1)) attained 99%, 93%, and 59% within 7, 40 and 200 h. The fungus exhibited tolerance to coliform and non-coliform bacteria on rich organic media, the inhibition occurred only on media containing tryptone and NaCl. The degradation efficiency in RBC reactor, capability to decolorize a wide range of dye structures and tolerance to bacterial stress make D. squalens an organism applicable to remediation of textile wastewaters.

  11. Kinetics study of metaxalone degradation under hydrolytic, oxidative and thermal stress conditions using stability- indicating HPLC method

    Institute of Scientific and Technical Information of China (English)

    Vamsi Krishna Marothu; Rajendra N. Dash; Saritha Vemula; Shravani Donkena; Ramesh Devi; Madhavi Gorrepati

    2012-01-01

    An isocratic stability indicating RP-HPLC-UV method is presented for the determina- tion of metaxalone (MET) in the presence of its degradation products. The method uses Dr. Maisch C18 column (250 mm × 4.6 mm, 5μm) with mobile phase consisting of acetonitrile-potassium dihydrogen orthophosphate buffer with 4 mL of 0.4% triethyl amine (pH 3.0; 10 mM) (58:42, v/v) at a flow rate of 1.0 mL/min, pH of the buffer was adjusted with o-phosphoric acid. UV detection was performed at 225 nm. The method was validated for specificity, linearity, precision, accuracy, limit of detection, limit of quantification and robustness. The calibration plot was linear over the concentration range of 1-100 μg/mL having a correlation coefficient (r2) of 0.999. Limits of detection and quantification were 0.3 and 1μg/mL, respectively. Intra-day and inter-day precision (% RSD) was 0.65 and 0.79 respectively. The proposed method was used to investigate the degradation kinetics of MET under different stress conditions employed. Degradation of MET followed a pseudo-first-order kinetics, and rate constant (K), time left for 50% potency (t1/2), and time left for 90% potency 090) were calculated.

  12. Analysis of accelerated degradation of a HT-PEM fuel cell caused by cell reversal in fuel starvation condition

    DEFF Research Database (Denmark)

    Zhou, Fan; Andreasen, Søren Juhl; Kær, Søren Knudsen;

    2015-01-01

    This paper reports an accelerated degradation test of a high temperature PEM fuel cell under repeated H2 starvation condition. The H2 stoichiometry is cycled between 3.0 and 0.8 every 2 min during the test. The experimental results show that the polarity of the fuel cell is reversed under H2...... starvation condition, and the cell performance indicated by cell voltage at H2 stoichiometry of 3.0 declines from 0.59 V to 0.41 V in 19 cycles. Since CO2 is detected in anode exhaust under H2 starvation condition, carbon corrosion is believed to be the reason for the degradation in this test. After the test......, there is only a slight decrease in open circuit voltage of the fuel cell which implies the membrane is not affected by the test. The electrochemical impedance spectrum measurement shows that the H2 starvation can cause significant increase in the ohmic resistance and charge transfer resistance. By looking...

  13. Degradation of alumina and zirconia toughened alumina (ZTA) hip prostheses tested under microseparation conditions in a shock device

    CERN Document Server

    Uribe, Juliana; Gremillard, Laurent; Reynard, Bruno

    2013-01-01

    This paper considers the degradation of alumina and zirconia toughened alumina vs. alumina for hip implants. The materials are as assumed to be load bearing surfaces subjected to shocks in wet conditions. The load is a peak of force; 9 kN was applied over 15 ms at 2 Hz for 800,000 cycles. The volumetric wear and roughness are lower for ZTA than for alumina. The long ZTA ageing did not seem to have a direct influence on the roughness. The ageing increased the wear volumes of ZTA and it was found to have a higher wear resistance compared to alumina.

  14. Microbial Degradation of Phenols and Aromatic Hydrocarbons in Creosote-contaminated Groundwater Under Nitrate-reducing Conditions

    DEFF Research Database (Denmark)

    Flyvbjerg, John; Arvin, Erik; Jensen, Bjørn K.

    1993-01-01

    Batch experiments were carried out to investigate the biodegradation of phenols and aromatic hydrocarbons under anaerobic, nitrate-reducing conditions in groundwater from a creosote-contaminated site at Fredensborg, Denmark. The bacteria in the creosote-contaminated groundwater degraded a mixture......-reducing batches disappearance of toluene, phenol, o-cresol and o-cresol was observed, whereas no removal of benzene, the xylenes, naphthalane, 2,3-DMP, 2,4-DMP, 2,5-DMP and 3,5-DMP was detected during 7 months of incubation....

  15. Support-dependent active species formation for CuO catalysts: Leading to efficient pollutant degradation in alkaline conditions.

    Science.gov (United States)

    Li, Yibing; Guo, Lianshuang; Huang, Dekang; Jawad, Ali; Chen, Zhuqi; Yang, Jiakuan; Liu, Weidong; Shen, Yan; Wang, Mingkui; Yin, Guochuan

    2017-04-15

    Redox metal ions play the crucial role in versatile advanced oxidation technologies, in which controlling the active species formation through catalyst design is one of the key challenges in oxidant utilization. This work describes an example of different active species formations in CuO-mediated degradation just because of supporting material differences. Although three CuO catalysts were prepared by similar procedures, it was found that CuO-MgO catalyst demonstrated high efficiency in phenol degradation with bicarbonate activated H2O2, in which the superoxide radical is crucial, while hydroxyl radical and singlet oxygen are ignorable. For the CuO-MgO-Al2O3 and CuO-Al2O3 catalysts, the degradation proceeds by popular hydroxyl radical based process, however, the efficiency was poor. The EPR experiments also confirmed the absence of hydroxyl radical in CuO-MgO system but its presence in CuO-MgO-Al2O3 and CuO-Al2O3 system. The high catalytic efficiency with ignorable hydroxyl radical in the CuO-MgO system leads us to propose that an alternative Cu(III) species dominates the degradation. The basic MgO support may facilitate the formation of the Cu(III) species, whereas the neutral MgO-Al2O3 and acidic Al2O3 supports are unable to stabilize the high valent Cu(III) species, leading to the common hydroxyl radical mechanism with low efficiency of H2O2 in alkaline conditions. Copyright © 2016. Published by Elsevier B.V.

  16. Absolute Depth Sensitivity in Cat Primary Visual Cortex under Natural Viewing Conditions.

    Science.gov (United States)

    Pigarev, Ivan N; Levichkina, Ekaterina V

    2016-01-01

    Mechanisms of 3D perception, investigated in many laboratories, have defined depth either relative to the fixation plane or to other objects in the visual scene. It is obvious that for efficient perception of the 3D world, additional mechanisms of depth constancy could operate in the visual system to provide information about absolute distance. Neurons with properties reflecting some features of depth constancy have been described in the parietal and extrastriate occipital cortical areas. It has also been shown that, for some neurons in the visual area V1, responses to stimuli of constant angular size differ at close and remote distances. The present study was designed to investigate whether, in natural free gaze viewing conditions, neurons tuned to absolute depths can be found in the primary visual cortex (area V1). Single-unit extracellular activity was recorded from the visual cortex of waking cats sitting on a trolley in front of a large screen. The trolley was slowly approaching the visual scene, which consisted of stationary sinusoidal gratings of optimal orientation rear-projected over the whole surface of the screen. Each neuron was tested with two gratings, with spatial frequency of one grating being twice as high as that of the other. Assuming that a cell is tuned to a spatial frequency, its maximum response to the grating with a spatial frequency twice as high should be shifted to a distance half way closer to the screen in order to attain the same size of retinal projection. For hypothetical neurons selective to absolute depth, location of the maximum response should remain at the same distance irrespective of the type of stimulus. It was found that about 20% of neurons in our experimental paradigm demonstrated sensitivity to particular distances independently of the spatial frequencies of the gratings. We interpret these findings as an indication of the use of absolute depth information in the primary visual cortex.

  17. ICH GUIDANCE IN PRACTICE: DEVELOPMENT OF A VALIDATED STABILITY-INDICATING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHIC ASSAY METHOD FOR FEBUXOSTAT AND DEGRADATION KINETIC STUDY IN ACID HYDROLYTIC CONDITION

    Directory of Open Access Journals (Sweden)

    Megha V. Sheth* and Jigar J. Pandya

    2013-02-01

    Full Text Available The degradation behavior of Febuxostat was investigated under different stress degradation (hydrolytic, oxidative, photolytic and thermal conditions recommended by International Conference on Harmonization (ICH using HPLC and LCMS. Febuxostat was found to degrade significantly in acidic and alkaline conditions as well as in neutral hydrolysis. The drug was stable to dry heat, photolytic degradation and under oxidative condition. Resolution of drug and the degradation products formed under different stress studies were successfully achieved on a C-18 column utilizing Methanol- water (with 0.02%v/v TFA in the ratio of 95:5 and at the detection wavelength of 315 nm. The method was validated with respect to linearity, precision, accuracy, selectivity and specificity. The degradation kinetic of Febuxostat in acidic condition at different temperature was studied. The reaction order for Febuxostat in aqueous solvent system followed pseudo first order degradation kinetic. The catalytic rate constant and half-life at particular condition were determined. The Arrhenius plot showed the temperature dependence of Febuxostat.

  18. Rapid degradation of Congo red by molecularly imprinted polypyrrole-coated magnetic TiO{sub 2} nanoparticles in dark at ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Shoutai; Hu, Xiaolei; Liu, Hualong; Wang, Qiang; He, Chiyang, E-mail: chiyanghe@hotmail.com

    2015-08-30

    Highlights: • Molecularly imprinted polypyrrole-coated magnetic TiO{sub 2} catalyst was prepared. • The catalyst degraded Congo red rapidly in dark at ambient conditions. • Degradation mechanism was proposed according to LC–MS analysis. • The catalyst can be easily recycled by a magnet. - Abstract: A novel molecularly imprinted polymer (MIP)-coated magnetic TiO{sub 2} nanocomposite was prepared, using methyl orange (MO) as the dummy template and pyrrole as functional monomer, for degradation of Congo red (CR). The nanocomposite was characterized by Fourier transform infrared spectroscopy, thermo-gravimetric analysis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The imprinting efficiency of the imprinted nanoparticles was investigated by static binding test, and their degradation ability toward CR was also studied. Moreover, the effects of pH, temperature, dissolved oxygen and oscillation rate on degradation rate of CR were investigated. Results showed that the imprinted nanocomposite had higher adsorption ability for MO compared with the non-imprinted one. Moreover, it could degrade CR rapidly in dark at room temperature and atmospheric pressure and could be recycled easily by a magnet with a good reusability. A degradation mechanism was proposed according to LC–MS analysis of degradation products of CR. The new imprinted nanoparticles showed high catalytic activity at ambient conditions without light illumination and additional chemicals, and therefore, it can be potentially applied to the rapid, “green” and low-cost degradation of CR in industrial printing and dyeing wastewater.

  19. Targeted Protein Degradation by Salmonella under Phagosome-Mimicking Culture Conditions Investigated Using Comparative Peptidomics

    Energy Technology Data Exchange (ETDEWEB)

    Manes, Nathan P.; Gustin, Jean K.; Rue, Joanne; Mottaz, Heather M.; Purvine, Samuel O.; Norbeck, Angela D.; Monroe, Matthew E.; Zimmer, Jennifer S.; Metz, Thomas O.; Adkins, Joshua N.; Smith, Richard D.; Heffron, Fred

    2007-04-01

    The pathogen Salmonella enterica is known to cause both food poisoning and typhoid fever. Due to the emergence of antibiotic-resistant isolates and the threat of bioterrorism (e.g., contamination of the food supply), there is a growing need to study this bacterium. In this investigation, comparative peptidomics was used to study Salmonella enterica serovar Typhimurium cultured in either a rich medium or in an acidic, low magnesium, and minimal nutrient medium designed to roughly mimic the macrophage phagosomal compartment (within which Salmonella are known to survive). Native peptides from cleared cell lysates were enriched by using isopropanol extraction and analyzed by using both LC-MS/MS and LC-FTICR-MS. We identified 5,163 distinct peptides originating from 682 proteins and the data clearly indicated that compared to cells cultured in the rich medium, Salmonella cultured in the phagosome-mimicking medium had dramatically higher abundances of a wide variety of protein degradation products, especially from ribosomal proteins. Salmonella from the same cultures were also analyzed by using bottom-up proteomics, and when the peptidomic and proteomic data were analyzed together, two clusters of proteins targeted for proteolysis were tentatively identified. Possible roles of targeted proteolysis by phagocytosed Salmonella are discussed.

  20. Highly fluorescence-stable blue CdZnS/ZnS quantum dots against degradable environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Heon; Lee, Jeong-Hoon; Kang, Hee-Don; Han, Chang-Yeol [Department of Materials Science and Engineering, Hongik University, Seoul 121-791 (Korea, Republic of); Bae, Seung Muk [Kunsan National University Center For Research Facilities, Kunsan National University, Gunsan, Jeonbuk 573-701 (Korea, Republic of); Lee, Yangjin; Hwang, Jun Yeon [Institute of Advanced Composite Materials, Korea Institute of Science and Technology, Jeonbuk 565-905 (Korea, Republic of); Yang, Heesun, E-mail: hyang@hongik.ac.kr [Department of Materials Science and Engineering, Hongik University, Seoul 121-791 (Korea, Republic of)

    2014-10-15

    Graphical abstract: Blue-emitting CdZnS/ZnS alloy QDs exhibited the excellent fluorescent stability against a thorough purification cycle, long-term UV illumination, and hydrophobic-to-hydrophilic ligand exchange. - Highlights: • Highly efficient, color-pure blue CdZnS/ZnS QDs are synthesized. • Fluorescent properties of the QDs remain unchanged against various degradable conditions. • Closely-packed solid QD film is compared with QD solution in PL QY and emission decay dynamics. - Abstract: We report on synthesis of highly efficient, color-pure blue CdZnS/ZnS quantum dots (QDs) and their excellent fluorescent stability against degradable environmental conditions. The CdZnS/ZnS QDs finely emission-tunable in the range of 440–461 nm exhibit high photoluminescence (PL) quantum yields (QYs) of 81–92% along with an exceptionally narrow spectral bandwidth of 19 nm. These QDs are subjected to various post-treatments of a thorough purification cycle, long-term UV illumination, and hydrophobic-to-hydrophilic ligand exchange, each of which is usually detrimental to QD fluorescence. As a result, no noticeable deterioration in the fluorescent properties is observed, indicative of the insensitiveness of our CdZnS/ZnS QDs to the above degradable processes. Furthermore, PL properties of a solid film of multiple QD layers are assessed and compared with those of a diluted QD solution, showing an unprecedentedly small QY reduction of solid QD film versus QD solution. The above promising results are justified mainly by emphasizing the role of a thick ZnS shell present in CdZnS/ZnS QDs.

  1. Seed banks in a degraded desert shrubland: Influence of soil surface condition and harvester ant activity on seed abundance

    Science.gov (United States)

    DeFalco, L.A.; Esque, T.C.; Kane, J.M.; Nicklas, M.B.

    2009-01-01

    We compared seed banks between two contrasting anthropogenic surface disturbances (compacted, trenched) and adjacent undisturbed controls to determine whether site condition influences viable seed densities of perennial and annual Mojave Desert species. Viable seeds of perennials were rare in undisturbed areas (3-4 seeds/m2) and declined to harvester ant explained annual seed densities better than any other surface characteristics that were examined. Surface disturbances can have a varied impact on the condition of the soil surface in arid lands. Nevertheless, the consistently positive relationship between ground cover of litter and viable seed density emphasizes the importance of litter as an indicator of site degradation and recovery potential in arid lands.

  2. Electrochemical treatment of iopromide under conditions of reverse osmosis concentrates--elucidation of the degradation pathway.

    Science.gov (United States)

    Lütke Eversloh, C; Henning, N; Schulz, M; Ternes, T A

    2014-01-01

    Application of reverse osmosis for the reuse of treated wastewater on the one hand offers a way to provide high quality effluent waters. On the other hand reverse osmosis concentrates exhibiting highly concentrated contaminants are produced simultaneously. Electrochemical treatment of those concentrates is regarded as one possible answer to the problem of their disposal into surface waters. Nevertheless, due to the diversity of direct and indirect degradation processes during electrolysis, special care has to be taken about the formation of toxic transformation products (TPs). In this study the electrochemical transformation of the X-ray contrast medium iopromide was investigated as a representative of biologically persistent compounds. For this purpose, anodic oxidation at boron doped diamond as well as cathodic reduction using a platinum electrode were considered. Kinetic analyses revealed a transformation of 100 μM iopromide with first order kinetic constants between 0.6 and 1.6 × 10(-4) s(-1) at the beginning and a subsequent increase of the reaction order due to the influence of secondary oxidants formed during electrolysis. Mineralization up to 96% was achieved after about 7.5 h. At shorter treatment times several oxidatively and reductively formed transformation products were detected, whereas deiodinated iopromide represented the major fraction. Nevertheless, the latter exhibited negligible toxicological relevance according to tests on vibrio fisheri. Additional experiments utilizing a divided cell setup enabled the elucidation of the transformation pathway, whereas emerging TPs could be identified by means of high resolution mass spectrometry and MS(n)-fragmentations. During electrolysis the iodine released from Iopromide was found to 90% as iodide and to 10% as iodate even in the open cell experiments, limiting the potential formation of toxic iodo-disinfection by-products. Chlorinated TPs were not found.

  3. Mechanical properties of electrospun PCL scaffold under in vitro and accelerated degradation conditions

    DEFF Research Database (Denmark)

    Løvdal, Alexandra Liv Vest; Vange, Jakob; Nielsen, Lene Feldskov

    2014-01-01

    Within recent years, researchers have looked into using polycaprolactone (PCL) as a synthetic biodegradable scaffold for tissue engineering purposes. This study investigated the mechanical properties of an electrospun PCL, while being exposed to physiological fluids at 37C (in vitro conditions...

  4. Pretreatment combining ultrasound and sodium percarbonate under mild conditions for efficient degradation of corn stover.

    Science.gov (United States)

    Nakashima, Kazunori; Ebi, Yuuki; Kubo, Masaki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

    2016-03-01

    Ultrasound (US) can be used to disrupt microcrystalline cellulose to give nanofibers via ultrasonic cavitation. Sodium percarbonate (SP), consisting of sodium carbonate and hydrogen peroxide, generates highly reactive radicals, which cause oxidative delignification. Here, we describe a novel pretreatment technique using a combination of US and SP (US-SP) for the efficient saccharification of cellulose and hemicellulose in lignocellulosic corn stover. Although US-SP pretreatment was conducted under mild condition (i.e., at room temperature and atmospheric pressure), the pretreatment greatly increased lignin removal and cellulose digestibility. We also determined the optimum US-SP treatment conditions, such as ultrasonic power output, pretreatment time, pretreatment temperature, and SP concentration for an efficient cellulose saccharification. Moreover, xylose could be effectively recovered from US-SP pretreated biomass without the formation of microbial inhibitor furfural.

  5. Degradation of High Voltage Polymeric Insulators in Arid Desert's Simulated Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Yasin Khan

    2009-01-01

    Full Text Available Problem statement: High Voltage (HV polymeric insulators are replacing ceramic insulator commonly used for HV outdoor networks due to their ease of handling, reliability and cost. However, their long term performance and reliability are major concerns to power utilities. Approach: To investigate their performance in arid desert's conditions, two types of HV composite insulators were aged as per International Electrochemical Commission (IEC standard-61109. Additional test samples were subjected to accelerated aging conditions simulating the actual Ultraviolet (UV radiation intensity and temperature in the inland desert. Results: This study described the experimental results of the effects of thermo electric stress and UV radiations on the polymeric insulators aged under two conditions i.e., as per IEC standard and modified IEC standard that simulates the inland arid desert. The tests results after the artificial accelerated aging indicated that the dielectric response of thermoplastic insulators under the tested thermo-electric cum UV-irradiations outperforms Silicone rubber insulators.Conclusion: From the obtained results it will be easy to assess the performance and suitability of composite insulators for their applications in arid desert environments.

  6. New views on the degradation and disposition of organic particles as collected by sediment traps in the open sea

    Science.gov (United States)

    Banse, Karl

    1990-07-01

    Sharp gradients with depth ( z) of fluxes ( F) and concentrations ( C) of organic particles are present in the upper few 100 m of the open sea. Because of under-determination of the system in the field, the balance of processes that maintain these gradients cannot yet be specified. A new scenario, with both quickly settling ( ˜ 100 m d -1), slowly decaying material and slowly sinking ( ˜ 20-33 m d -1), labile material that is degraded from within, mimics the observed gradients of F and C. A critique of recent ideas, which minimize decomposition of particles from within, notes that unambiguous interpretation in differences of cumulative particle collection between poisoned and live traps is difficult if daily decomposition rates of ˜ 20 to ˜ 30% prevail; these are claimed here for the labile fraction but have occasionally been observed even in bulk material from traps. The gradients with depth of F or C cannot be modeled as due to a first-order reaction. In addition, the description C = azb may require b to change below the euphotic zone; quantitative and especially qualitative changes of mesozooplankton (0.2-0.3 mm) with depth are inferred as the cause. Finally, as in the euphotic zone, mesozooplankton might generate substantial amounts of dissolved organic matter at depth, which is presumably degraded by free-living bacteria. Attention to animals is urged for flux studies.

  7. Degradation of textile dyes using immobilized lignin peroxidase-like metalloporphines under mild experimental conditions

    Directory of Open Access Journals (Sweden)

    Zucca Paolo

    2012-12-01

    Full Text Available Abstract Background Synthetic dyes represent a broad and heterogeneous class of durable pollutants, that are released in large amounts by the textile industry. The ability of two immobilized metalloporphines (structurally emulating the ligninolytic peroxidases to bleach six chosen dyes (alizarin red S, phenosafranine, xylenol orange, methylene blue, methyl green, and methyl orange was compared to enzymatic catalysts. To achieve a green and sustainable process, very mild conditions were chosen. Results IPS/MnTSPP was the most promising biomimetic catalyst as it was able to effectively and quickly bleach all tested dyes. Biomimetic catalysis was fully characterized: maximum activity was centered at neutral pH, in the absence of any organic solvent, using hydrogen peroxide as the oxidant. The immobilized metalloporphine kept a large part of its activity during multi-cycle use; however, well-known redox mediators were not able to increase its catalytic activity. IPS/MnTSPP was also more promising for use in industrial applications than its enzymatic counterparts (lignin peroxidase, laccase, manganese peroxidase, and horseradish peroxidase. Conclusions On the whole, the conditions were very mild (standard pressure, room temperature and neutral pH, using no organic solvents, and the most environmental-friendly oxidant and a significant bleaching and partial mineralization of the dyes was achieved in approximately 1 h. Therefore, the process was consistent with large-scale applications. The biomimetic catalyst also had more promising features than the enzymatic catalysts.

  8. DEVELOPMENT AND VALIDATION OF A STABILITY INDICATING ASSAY METHOD OF MESALAMINE BY USING DIFFERENT STRESS DEGRADATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    S. H. Gatkal*, P. R. Mhatre, V. V. Chopade and P. D. Chaudhari

    2013-01-01

    Full Text Available A simple, sensitive, highly accurate UV spectrophotometric method has been developed for the determination of mesalamine in bulk and tablet dosage form. Solution of mesalamine in distilled water shows maximum absorbance at 330 nm. Beer’s law was obeyed in the concentration range of 2-16 μg/ml with the slope, intercept, correlation coefficient, detection and quantitation limits were also calculated. The proposed method has been applied successfully for the analysis of the drug in pure and in its tablets dosage forms. Result of percentage recovery and placebo interference shows that the method was not affected by the presence of common excipients. The method was validated by determining its sensitivity, accuracy and precision which proves suitability of the developed method for the routine estimation of mesalamine in bulk and solid dosage form. The method was then validated for different parameters as per the ICH (International Conference for Harmonization guidelines. Mesalamine was subjected to stress degradation under different conditions recommended by ICH. The samples generated were used for degradation studies using the developed method.

  9. Amino Acid and Peptide Utilization Profiles of the Fluoroacetate-Degrading Bacterium Synergistetes Strain MFA1 Under Varying Conditions.

    Science.gov (United States)

    Leong, Lex E X; Denman, Stuart E; Hugenholtz, Philip; McSweeney, Christopher S

    2016-02-01

    Synergistetes strain MFA1 is an asaccharolytic ruminal bacterium isolated based on its ability to degrade fluoroacetate, a plant toxin. The amino acid and peptide requirements of the bacterium were investigated under different culturing conditions. The growth of strain MFA1 and its fluoroacetate degradation rate were enhanced by peptide-rich protein hydrolysates (tryptone and yeast extract) compared to casamino acid, an amino acid-rich protein hydrolysate. Complete utilization and preference for arginine, asparagine, glutamate, glycine, and histidine as free amino acids from yeast extract were observed, while the utilization of serine, threonine, and lysine in free form and peptide-bound glutamate was stimulated during growth on fluoroacetate. A predominant peptide in yeast extract preferentially utilized by strain MFA1 was partially characterized by high-liquid performance chromatography-mass spectrometry as a hepta-glutamate oligopeptide. Similar utilization profiles of amino acids were observed between the co-culture of strain MFA1 with Methanobrevibacter smithii without fluoroacetate and pure strain MFA1 culture with fluoroacetate. This suggests that growth of strain MFA1 could be enhanced by a reduction of hydrogen partial pressure as a result of hydrogen removal by a methanogen or reduction of fluoroacetate.

  10. Imaging wellbore cement degradation by carbon dioxide under geologic sequestration conditions using X-ray computed microtomography.

    Science.gov (United States)

    Jung, Hun Bok; Jansik, Danielle; Um, Wooyong

    2013-01-02

    X-ray microtomography (XMT), a nondestructive three-dimensional imaging technique, was applied to demonstrate its capability to visualize the mineralogical alteration and microstructure changes in hydrated Portland cement exposed to carbon dioxide under geologic sequestration conditions. Steel coupons and basalt fragments were added to the cement paste in order to simulate cement-steel and cement-rock interfaces. XMT image analysis showed the changes of material density and porosity in the degradation front (density: 1.98 g/cm(3), porosity: 40%) and the carbonated zone (density: 2.27 g/cm(3), porosity: 23%) after reaction with CO(2)-saturated water for 5 months compared to unaltered cement (density: 2.15 g/cm(3), porosity: 30%). Three-dimensional XMT imaging was capable of displaying spatially heterogeneous alteration in cement pores, calcium carbonate precipitation in cement cracks, and preferential cement alteration along the cement-steel and cement-rock interfaces. This result also indicates that the interface between cement and host rock or steel casing is likely more vulnerable to a CO(2) attack than the cement matrix in a wellbore environment. It is shown here that XMT imaging can potentially provide a new insight into the physical and chemical degradation of wellbore cement by CO(2) leakage.

  11. Conditioned Media from Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Inhibits Melanogenesis by Promoting Proteasomal Degradation of MITF.

    Directory of Open Access Journals (Sweden)

    Eun Sung Kim

    Full Text Available Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs secrete various beneficial molecules, which have anti-apoptotic activity and cell proliferation. However, the effect of hUCB-MSCs in melanogenesis is largely unclear. In this study, we show that conditioned media (CM derived from hUCB-MSCs inhibit melanogenesis by regulating microphthalmia-associated transcription factor (MITF expression via the ERK signalling pathway. Treatment of hUCB-MSC-CM strongly inhibited the alpha-melanocyte stimulating hormone-induced hyperpigmentation in melanoma cells as well as melanocytes. Treatment of hUCB-MSC-CM induced ERK1/2 activation in melanocytes. In addition, inhibition of ERK1/2 suppressed the anti-pigmentation activity of the hUCB-MSC-CM in melanocytes and in vitro artificial skin models. We also found that the expression of MITF was appreciably diminished while expression of phosphorylated MITF, which leads to its proteasomal degradation, was increased in cells treated with hUCB-MSC-CM. These results suggested that hUCB-MSC-CM significantly suppresses melanin synthesis via MITF degradation by the ERK pathway activation.

  12. Effects of Frame of Reference and Viewing Condition on Attentional Issues with Helmet Mounted Displays

    Science.gov (United States)

    1998-01-01

    dominant image may shift from eye to eye, so that the two monocular views will appear as alternating images ( Arditi , 1986; Davis, 1997). Thus, the... Arditi , A. (1986). Binocular vision. In K.R. Boff, L. Kaufman, and J.P. Thomas (Eds.), Handbook of Perception and Human Performance. Vol 1, New

  13. Degradation of mechanical properties of CrMo creep resistant steel operating under conditions of creep

    Directory of Open Access Journals (Sweden)

    J. Michel

    2012-01-01

    Full Text Available Mechanical properties of a steam tube made of CrMo creep resistant steel are analysed in this contribution after up to 2,6•105 hours service life in creep conditions at temperature 530 °C and calculated stress level in the tube wall 46,5 MPa. During service life there were in the steel gradual micro structure changes, fi rst pearlite spheroidization, precipitation, coaugulation and precipitate coarsening. Nevertheless the strength and deformation properties of the steel (Re, Rm, A5, Z, and the resistance to brittle fracture and the creep strength limit, were near to unchanged after 2,1•105 hours in service. The steam tube is now in service more than 2,6•105 h.

  14. Lytic polysaccharide monooxygenases: a crystallographer’s view on a new class of biomass-degrading enzymes

    Science.gov (United States)

    Frandsen, Kristian E. H.; Lo Leggio, Leila

    2016-01-01

    Lytic polysaccharide monooxygenases (LPMOs) are a new class of microbial copper enzymes involved in the degradation of recalcitrant polysaccharides. They have only been discovered and characterized in the last 5–10 years and have stimulated strong interest both in biotechnology and in bioinorganic chemistry. In biotechnology, the hope is that these enzymes will finally help to make enzymatic biomass conversion, especially of lignocellulosic plant waste, economically attractive. Here, the role of LPMOs is likely to be in attacking bonds that are not accessible to other enzymes. LPMOs have attracted enormous interest since their discovery. The emphasis in this review is on the past and present contribution of crystallographic studies as a guide to functional understanding, with a final look towards the future. PMID:27840684

  15. 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.

  16. The framing effect with rectangular and trapezoidal surfaces: actual and pictorial surface slant, frame orientation, and viewing condition.

    Science.gov (United States)

    Reinhardt-Rutland, A H

    1999-01-01

    The perceived slant of a surface relative to the frontal plane can be reduced when the surface is viewed through a frame between the observer and the surface. Aspects of this framing effect were investigated in three experiments in which observers judged the orientations-in-depth of rectangular and trapezoidal surfaces which were matched for pictorial depth. In experiments 1 and 2, viewing was stationary-monocular. In experiment 1, a frontal rectangular frame was present or absent during viewing. The perceived slants of the surfaces were reduced in the presence of the frame; the reduction for the trapezoidal surface was greater, suggesting that conflict in stimulus information contributes to the phenomenon. In experiment 2, the rectangular frame was either frontal or slanted; in a third condition, a frame was trapezoidal and frontal. The conditions all elicited similar results, suggesting that the framing effect is not explained by pictorial perception of the display, or by assimilation of the surface orientation to the frame orientation. In experiment 3, viewing was moving-monocular to introduce motion parallax; the framing effect was reduced, being appreciable only for a trapezoidal surface. The results are related to other phenomena in which depth perception of points in space tends towards a frontal plane; this frontal-plane tendency is attributed to heavy experimental demands, mainly concerning impoverished, conflicting, and distracting information.

  17. The radiolytic and chemical degradation of organic ion exchange resins under alkaline conditions: effect on radionuclide speciation

    Energy Technology Data Exchange (ETDEWEB)

    Loon, L. van; Hummel, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1995-10-01

    The formation of water soluble organic ligands by the radiolytic and chemical degradation of several ion exchange resins was investigated under conditions close to those of the near field of a cementitious repository. The most important degradation products were characterised and their role on radionuclide speciation evaluated thoroughly. Irradiation of strong acidic cation exchange resins (Powdex PCH and Lewatite S-100) resulted in the formation of mainly sulphate and dissolved organic carbon. A small part of the carbon (10-20%) could be identified as oxalate. The identity of the remainder is unknown. Complexation studies with Cu{sup 2+} and Ni{sup 2+} showed the presence of two ligands: oxalate and ligand X. Although ligand X could not be identified, it could be characterised by its concentration, a deprotonation constant and a complexation constant for the NiX complex. The influence of oxalate and ligand X on the speciation of radionuclides is examined in detail. For oxalate no significant influence on the speciation of radionuclides is expected. The stronger complexing ligand X may exert some influence depending on its concentration and the values of other parameters. These critical parameters are discussed and limiting values are evaluated. In absence of irradiation, no evidence for the formation of ligands was found. Irradiation of strong basic anion exchange resins (Powdex PAO and Lewatite M-500) resulted in the formation of mainly ammonia, amines and dissolved organic carbon. Up to 50% of the carbon could be identified as methyl-, dimethyl- and trimethylamine. Complexation studies with Eu{sup 3+} showed that the complexing capacity under near field conditions was negligible. The speciation of cations such as Ag, Ni, Cu and Pd can be influenced by the presence of amins. The strongest amine-complexes are formed with Pd and therefore, as an example, the aqueous Pd-ammonia system is examined in great detail. (author) 30 figs., 10 tabs., refs.

  18. Residues and Analysis of Degradation of Novel Fungicide Picoxystrobin in Cucumber and Soil Under Field Conditions

    Directory of Open Access Journals (Sweden)

    SUN Yang

    2014-10-01

    Full Text Available The analytical method for the residues of picoxystrobin in cucumber vegetable and soil matrices was developed and the dissipation of picoxystrobin under field conditions was studied. The limit of detection(LODof picoxystrobin was 3.5×10 -11 g and the limit of quantifica-tion(LOQwas found to be 0.005 mg·kg -1 in cucumber and soil. At three different spiking levels(0.005, 0.05, 0.25 mg·kg -1, mean recoveries and relative standard deviation(RSDfrom fortified samples in five replicated experiments for each matrix were in the range of 68.61%-122.4% and 1.06%-17.2%, respectively. The results showed that the half-lives of picoxystrobin in cucumber and soil from Tianjin City were 5.71 d and 12.9 d, respectively, the half-lives of picoxystrobin in cucumber and soil from Shandong Province were 2.70 d and 10.3 d, respec-tively, and the half-lives of picoxystrobin in cucumber and soil from Jiangsu Province were 9.76 d and 14.9 d, respectively. The maximum residual concentration of picoxystrobin on the 5th day after the last application was 0.014 mg· kg -1, much lower than the Maximum Residue Limits(MRLsfor picoxystrobin in cucumber according to the standards of EU(0.05 mg·kg-1.

  19. Degradation of polynuclear aromatic hydrocarbons under bench-scale compost conditions

    Energy Technology Data Exchange (ETDEWEB)

    Potter, C.L.; Glaser, J.A.; Chang, L.W.; Meier, J.R.; Dosani, M.A.; Herrmann, R.F. [US Environmental Protection Agency, Cincinnati, OH (United States). National Risk Management Research Lab.

    1999-05-15

    Polycyclic aromatic hydrocarbons are a concern at many sites, including wood-treating facilities and manufactured gas plants. This research sought to evaluate the relationship between aerobic biomass development and removal of 19 individual PAHs and toxicity from field soil during the composting process in in-vessel reactors located at the US Environmental Protection Agency (EPA) Test & Evaluation (T & E) Facility in Cincinnati, OH. Five compost amendment conditions were formulated from different nutrients or amendments to the reactor mixtures. Operating parameters of interest included aeration, moisture dynamics, and heat production. Toxicity tests were conducted to evaluate the effect of composting on soil toxicity. Seed germination and root elongation tests were evaluated in lettuce and oats, and genotoxicity (mitotic abberations) testing was performed on Allium cepa (onion). Composting of PAH contaminated soil decreased toxicity to earthworms and oat roots but had no significant effect on lettuce root toxicity. Untreated soil evoked genotoxicity in the Allium assay. After composting, no significant genotoxicity was observed in Reilly soil. 35 refs., 5 figs., 7 tabs.

  20. Vitamin A is rapidly degraded in retinyl palmitate-fortified soybean oil stored under household conditions.

    Science.gov (United States)

    Pignitter, Marc; Dumhart, Bettina; Gartner, Stephanie; Jirsa, Franz; Steiger, Georg; Kraemer, Klaus; Somoza, Veronika

    2014-07-30

    Oil fortification with retinyl palmitate is intended to lower the prevalence of vitamin A deficiency in populations at risk. Although the stability of vitamin A in vegetable oil has been shown to depend on environmental factors, very little information is known about the stability of vitamin A in preoxidized vegetable oils. The present study investigated the stability of retinyl palmitate in mildly oxidized (peroxide value 10 mequiv O2/kg) soybean oil stored under domestic and retail conditions. Soybean oil was filled in transparent bottles, which were exposed to cold fluorescent light at 22 or 32 °C for 56 days. Periodic oil sampling increased the headspace, thereby mimicking consumer handling. Loss of retinyl palmitate in soybean oil by a maximum of 84.8 ± 5.76% was accompanied by a decrease of vitamin E by 53.3 ± 0.87% and by an increase of the peroxide value from 1.20 ± 0.004 to 24.3 ± 0.02 mequiv O2/kg. Fortification of highly oxidized oil with 31.6 IU/g retinyl palmitate led to a doubling of the average decrease of retinol per day compared to fortification of mildly oxidized oil. In conclusion, oil fortification programs need to consider the oxidative status of the oil used for retinyl palmitate fortification.

  1. Differential effects of mineral and organic acids on the kinetics of arabinose degradation under lignocellulose pretreatment conditions

    NARCIS (Netherlands)

    Kootstra, A.M.J.; Mosier, N.S.; Scott, E.L.; Beeftink, H.H.; Sanders, J.P.M.

    2009-01-01

    Sugar degradation occurs during acid-catalyzed pretreatment of lignocellulosic biomass at elevated temperatures, resulting in degradation products that inhibit microbial fermentation in the ethanol production process. Arabinose, the second most abundant pentose in grasses like corn stover and wheat

  2. Biodegradation of malachite green by Pseudomonas sp. strain DY1 under aerobic condition: characteristics, degradation products, enzyme analysis and phytotoxicity.

    Science.gov (United States)

    Du, Lin-Na; Wang, Sheng; Li, Gang; Wang, Bing; Jia, Xiao-Ming; Zhao, Yu-Hua; Chen, Yun-Long

    2011-03-01

    Malachite green (MG), a widely-used and recalcitrant dye, has been confirmed to be carcinogenic and mutagenic against many organisms. The main objective of this study is to investigate the capability of Pseudomonas sp. strain DY1 to decolorize MG, and to explore the possible mechanism. The results showed that this strain demonstrated high decolorizing capability (90.3-97.2%) at high concentrations of MG (100-1,000 mg/l) under shaking condition within 24 h. In static conditions, lower but still effective decolorization (78.9-84.3%) was achieved. The optimal pH and temperature for the decolorization was pH 6.6 and 28-30°C, respectively. Mg(2+) and Mn(2+) (1 mM) were observed to significantly enhance the decolorization. The intermediates of the MG degradation under aerobic condition identified by UV-visible, GC-MS and LC-MS analysis included malachite green carbinol, (dimethyl amino-phenyl)-phenyl-methanone, N,N-dimethylaniline, (methyl amino-phenyl)-phenyl-methanone, (amino phenyl)-phenyl methanone and di-benzyl methane. The enzyme analysis indicated that Mn-peroxidase, NADH-DCIP and MG reductase were involved in the biodegradation of MG. Moreover, phytotoxicity of MG and detoxification for MG by the strain were observed. Therefore, this strain could be potentially used for bioremediation of MG.

  3. Permafrost in the Yukon-Kuskokwim Delta, Alaska: a case for a holistic and integrated view of permafrost degradation

    Science.gov (United States)

    Herman-Mercer, N. M.; Schuster, P. F.; Laituri, M.; Elder, K.; Mutter, E. A.; Massey, M.; Matkin, E.; Toohey, R.

    2016-12-01

    The Yukon-Kuskokwim Delta (YKD) region of Alaska is a vast, marshy, lowland plain, underlain by discontinuous permafrost vulnerable to degradation. This region has been home to the Yup'ik and Cup'ik people, subsisting on local resources for centuries. Permafrost thaw in northern latitudes has become the focus of extensive scientific research in recent decades. However, the indigenous residents that live in these areas of degrading permafrost have been largely left out of scientific discussion and studies. More than fifty semi-structured interviews were conducted in four YKD communities. Interview questions were focused on the broad themes of seasonality of subsistence systems and observations of weather and landscape change. Responses revealed the myriad ways people interact with and observe permafrost in their day to day lives. For instance, permafrost is still utilized for food storage, people encounter permafrost when digging graves, and observe permafrost thaw in damage to their homes and other infrastructure in their communities. Yup'ik and Cup'ik residents have an intimate knowledge of the landscape owing to their subsistence based lifestyle and have reported observations of slumping ground, eroding river banks and coast lines as well as land that seems to be rising. Indigenous knowledge and observations complement broader scientific studies and should be used to inform permafrost research and assist in reconstructing historical baselines of permafrost distribution and active layer depth. Further, results of scientific research must be communicated to the people that may be impacted by present and future changes to permafrost that will likely result in changes to hydrologic flowpaths and ultimately ecosystem dynamics that may impact subsistence. Over millennia, northern indigenous communities have developed flexibility in resource harvesting and have exhibited adaptability to a variable and harsh environment. However, changes are being experienced at an

  4. 76 FR 63823 - Special Conditions: Gulfstream Aerospace LP (GALP) Model G280 Airplane Pilot-Compartment View...

    Science.gov (United States)

    2011-10-14

    ...These special conditions are issued for the Gulfstream Aerospace LP (GALP) Model G280 airplane. This airplane will have a novel or unusual design feature associated with the pilot-compartment view through a hydrophobic windshield coating, in lieu of windshield wipers. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.

  5. Analyzing pepsin degradation assay conditions used for allergenicity assessments to ensure that pepsin susceptible and pepsin resistant dietary proteins are distinguishable

    Science.gov (United States)

    Edrington, Thomas C.; Storrs, S. Bradley; Crowley, Kathleen S.; Ward, Jason M.; Lee, Thomas C.; Liu, Zi L.; Li, Bin; Glenn, Kevin C.

    2017-01-01

    The susceptibility of a dietary protein to proteolytic degradation by digestive enzymes, such as gastric pepsin, provides information on the likelihood of systemic exposure to a structurally intact and biologically active macromolecule, thus informing on the safety of proteins for human and animal consumption. Therefore, the purpose of standardized in vitro degradation studies that are performed during protein safety assessments is to distinguish whether proteins of interest are susceptible or resistant to pepsin degradation via a study design that enables study-to-study comparison. Attempting to assess pepsin degradation under a wide-range of possible physiological conditions poses a problem because of the lack of robust and consistent data collected under a large-range of sub-optimal conditions, which undermines the needs to harmonize in vitro degradation conditions. This report systematically compares the effects of pH, incubation time, and pepsin-to-substrate protein ratio on the relative degradation of five dietary proteins: three pepsin susceptible proteins [ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco), horseradish peroxidase (HRP), hemoglobin (Hb)], and two pepsin resistant proteins [lipid transfer protein (LTP) and soybean trypsin inhibitor (STI)]. The results indicate that proteins susceptible to pepsin degradation are readily distinguishable from pepsin-resistant proteins when the reaction conditions are within the well-characterized optima for pepsin. The current standardized in vitro pepsin resistant assay with low pH and high pepsin-to-substrate ratio fits this purpose. Using non-optimal pH and/or pepsin-to-substrate protein ratios resulted in susceptible proteins no longer being reliably degraded by this stomach enzyme, which compromises the ability of this in vitro assay to distinguish between resistant and susceptible proteins and, therefore, no longer providing useful data to an overall weight-of-evidence approach to assessing safety

  6. 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; Gomez, Juan Carlos; Happe, Francesca

    2010-01-01

    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…

  7. Effect of reaction conditions on methyl red degradation mediated by boron and nitrogen doped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Galenda, A., E-mail: galenda@ieni.cnr.it [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy); Crociani, L.; Habra, N. El; Favaro, M. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy); Natile, M.M. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo, 1 35131 Padova (Italy); Rossetto, G. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy)

    2014-09-30

    Highlights: • Boron and/or nitrogen-doped TiO{sub 2} for photocatalytic wastewater treatment. • Methyl red degradation/mineralisation as a function of pH, acids and dopants. • Adsorption time influence on photocatalytic process. • Recovery of worn-out catalyst. - Abstract: Nowadays the employment of renewable and sustainable energy sources, and solar light as main option, becomes an urgent need. Photocatalytic processes received great attention in wastewater treatment due to their cheapness, environmental compatibility and optimal performances. Despite the general low selectivity of the photocatalysts, an accurate optimisation of the operational parameters needs to be carried out in order to maximise the process yield. Because of this reason, the present contribution aims to deepen either the knowledge in boron and/or nitrogen doped TiO{sub 2}-based systems and their employment in methyl red removal from aqueous solutions. The samples were obtained by coprecipitation and characterised by XRD, SEM, BET specific surface area, UV–vis and XPS techniques. The catalytic activity was for the first time carefully evaluated with respect to methyl red photodegradation in different conditions as a function of working pH, counter-ions and pre-adsorption time. An ad-hoc study was performed on the importance of the pre-adsorption of the dye, suggesting that an extended adsorption is useless for the catalyst photoactivity, while a partial coverage is preferable. The photocatalytic tests demonstrate the positive influence of boron doping in photo-activated reactions and the great importance of the operational parameters with respect to the simple methyl red bleaching rather than the overall pollutant mineralisation. It is proved, indeed, that different working pH, acidifying means and substrate pre-adsorption time can enhance or limit the catalyst performances with respect to the complete pollutant degradation rather than its partial breakage.

  8. Preferential degradation of polyphenols from Sphagnum - 4-Isopropenylphenol as a proxy for past hydrological conditions in Sphagnum-dominated peat

    Science.gov (United States)

    Schellekens, Judith; Bindler, Richard; Martínez-Cortizas, Antonio; McClymont, Erin L.; Abbott, Geoffrey D.; Biester, Harald; Pontevedra-Pombal, Xabier; Buurman, Peter

    2015-02-01

    The net accumulation of remains of Sphagnum spp. is fundamental to the development of many peatlands. The effect of polyphenols from Sphagnum on decomposition processes is frequently cited but has barely been studied. The central area of the Rödmossamyran peatland (Sweden) is an open lawn that consists mostly of Sphagnum spp. with a very low contribution from vascular plants. In order to determine the effects of decay on sphagnum phenols, 53 samples of a 2.7 m deep core from this lawn were analysed with pyrolysis gas chromatography-mass spectrometry (pyrolysis-GC-MS) and compared with more traditional decomposition proxies such as C/N ratio, UV light transmission of alkaline peat extracts, and bulk density. Factor analysis of 72 quantified pyrolysis products suggested that the variation in 4-isopropenylphenol was largely determined by aerobic decomposition instead of Sphagnum abundance. In order to evaluate the effects of aerobic decay in Sphagnum peat, down-core records from different climatic regions were compared using molecular markers for plant biopolymers and C/N ratio. These included markers for lignin from vascular plants ((di)methoxyphenols), polyphenols from Sphagnum spp. (4-isopropenylphenol), and cellulose (levoglucosan). Our results indicate that polyphenols from Sphagnum are preferentially degraded over polysaccharides; consequently the variability of the marker for sphagnum acid, 4-isopropenylphenol, was found indicative of decomposition instead of reflecting the abundance of Sphagnum remains. The fact that 4-isopropenylphenol is aerobically degraded in combination with its specificity for Sphagnum spp. makes it a consistent indicator of past hydrological conditions in Sphagnum-dominated peat. In contrast, the variability of C/N records in Sphagnum-dominated peat was influenced by both vegetation shifts and decomposition, and the dominant effect differed between the studied peatlands. Our results provide direction for modelling studies that try to

  9. Research on patients with multiple health conditions: different constructs, different views, one voice

    Directory of Open Access Journals (Sweden)

    Jose M. Valderas

    2011-12-01

    Full Text Available Technological advances, improvements in medical care and public health policies have resulted in a growing proportion of patients with multiple health conditions. The prevalence of multiple health conditions among individuals increases with age, is substantial among older adults, and will increase dramatically in coming years [1–4]. This phenomenon has received growing interest in the most recent literature and has led to several – and often differing – conceptualizations. The term “comorbidity” was originally defined by Feinstein as “any distinct additional clinical entity that has existed or may occur during the clinical course of a patient who has the index disease under study” [5]. This definition places one disease in a central position and all other condition(s as secondary, in that they may or may not affect the course and treatment of the index disease [6]. Feinstein’s principle has been applied all too readily as if the effect of comorbidity was secondary or indeed negligible. In clinical research, individuals with a narrowly defined index condition and no major comorbidities are usually enrolled, leaving the majority of the patients seen in a typical family practice [7,8] out in the cold. In clinical practice, management of the index condition invariably takes priority, with disjointed – if any – treatment plans developed for each of the comorbidities [6]. This model of care is typical of delivery systems constructed around specialized care, where areas of expertise are defined around specific conditions and bodily systems [11]. Not surprisingly, clinical practice guidelines arising from that model of care lack pertinence for patients with multiple health conditions [9,10].

  10. A rapprochement of the operant-conditioning and awareness views of biofeedback training: the role of discrimination in voluntary control.

    Science.gov (United States)

    Plotkin, W B

    1981-09-01

    In order to adequately evaluate Cott, Pavloski and Black's claim that the discrimination of a physiological response is not necessary for the voluntary control of that response, this commentary presents a set of formal articulations and clarifications of intentional action, voluntary control, discrimination, awareness, and physiological response. It is concluded on logical grounds that Cott et al. are necessarily mistaken and that the conceptual foundations of the issue have not been clearly articulated heretofore. Based upon this discussion, a rapprochement is offered of the operant conditioning and awareness views of biofeedback training, demonstrating that the awareness view is essentially a tautology that aids us in understanding what is meant by "voluntary control of the physiological response." Finally, the issue of mediation in biofeedback-augmented self-regulation is reconceptualized and it is argued that the search for a "neurophysiological mechanism" of voluntary control is meaningless, reflecting a misappropriation of the concept of voluntary control.

  11. A thermodynamic view of tracer plume evolution: Complete mixing condition evaluation

    Directory of Open Access Journals (Sweden)

    Constain A.

    2013-05-01

    Full Text Available One of most controversial issues of modern tracer theory is the “complete mixing condition” because of its importance in evolution of hazardous solutes in natural flows. This condition named also as “Mixing length” measures the distance from pouring point when tracer particles have spread uniformly on cross section of stream. The point is that until now there is no rational, complete and easy to use formula to calculate it. Rather, this condition is evaluated mostly by means of empirical relationships; among them Ruthven's is one of current usage. Also there are statistical methods that applied by software packages allow to characterize this condition. However a new focus on this issue is important, because is necessary to tie together, generality, easiness and accuracy. This paper puts on discussion a thermodynamics method to understand when a tracer is in this remarkable condition. Herein it is developed the conditions when this method may be applied. It is shown also how the resulting formula is convergent with Ruthven's equation. An experimental demonstration is presented.

  12. [Modelling of the knee joint loading conditions in the view of mechanics].

    Science.gov (United States)

    Pustovoĭt, K B; Karpins'kyĭ, M Iu

    2013-02-01

    The results of mathematic modelling of work of femoropatellar joint in normal conditions and in the presence of dysplastic deformity were adduced. There was established, that a knee joint (KJ) by its external appearance and function constitutes a classic cam mechanism. Biomechanical scheme of interaction between the femoral bone processus and patella was elaborated. In accordance to scheme of cam mechanism its experimental roentgenometric investigations were performed. According to statistical analysis performed, in conditions of dysplasia in femoropatellar joint the changes in the KJ occur, which may cause its blockade; the patella position in the KJ depends on peculiarities of anatomical structure of the femoral bone processuses.

  13. A review on self-healing in reinforced concrete structures in view of serving conditions.

    NARCIS (Netherlands)

    Huang, H.; Ye, G.

    2014-01-01

    In this paper, different mechanisms of self-healing, i.e. self-healing based on adhesive agents, self-healing based on bacteria, self-healing based on autogenous self-healing were described. Their required conditions were summarized. The previous investigations showed that all mechanisms of self-hea

  14. Aquatic degradation of Cry1Ab protein and decomposition dynamics of transgenic corn leaves under controlled conditions.

    Science.gov (United States)

    Böttger, Rita; Schaller, Jörg; Lintow, Sven; Gert Dudel, E

    2015-03-01

    The increasing cultivation of genetically modified corn plants (Zea mays) during the last decades is suggested as a potential risk to the environment. One of these genetically modified variety expressed the insecticidal Cry1Ab protein originating from Bacillus thuringiensis (Bt), resulting in resistance against Ostrinia nubilalis, the European corn borer. Transgenic litter material is extensively studied regarding the decomposition in soils. However, only a few field studies analyzed the fate of the Cry1Ab protein and the impact of green and senescent leaf litter from corn on the decomposition rate and related ecosystem functions in aquatic environments. Consequently, a microbial litter decomposition experiment was conducted under controlled semi-natural conditions in batch culture using two maize varieties: one variety with Cry1Ab and another one with the appertaining Iso-line as control treatment. The results showed no significant differences between the treatment with Cry1Ab and the Iso-line regarding loss of total mass in dry weight of 43% for Iso-line and 45% for Bt-corn litter, lignin content increased to 137.5% (Iso-line) and 115.7% (Bt-corn), and phenol loss decreased by 53.6% (Iso-line), 62.2% (Bt-corn) during three weeks of the experiment. At the end of the experiment Cry1Ab protein was still detected with 6% of the initial concentration. A slightly but significant lower cellulose content was found for the Cry1Ab treatment compared to the Iso-line litter at the end of the experiment. The significant higher total protein (25%) and nitrogen (25%) content in Bt corn, most likely due to the additionally expression of the transgenic protein, may increase the microbial cellulose degradation and decrease microbial lignin degradation. In conclusion a relevant year by year input of protein and therefore nitrogen rich Bt corn litter into aquatic environments may affect the balanced nutrient turnover in aquatic ecosystems. Copyright © 2014 Elsevier Inc. All rights

  15. THREE DIMENSIONAL RECONSTRUCTION OF HUMAN HEART SURFACE FROM SINGLE IMAGE- VIEW UNDER DIFFERENT ILLUMINATION CONDITIONS

    Directory of Open Access Journals (Sweden)

    Aqeel Al-Surmi

    2013-01-01

    Full Text Available The 3D reconstruction from a single-view image is a longstanding issue in computer vision literature, especially in the medical field. Traditional medical imaging techniques that provide information about the heart and which are used to reconstruct the heart model, include Magnetic Resonance Imaging (MRI and Computed Tomography (CT images. However, in some cases, they are not available and the applications that use these techniques to model the human heart only produce acceptable results after a long process, which involves acquiring the input data, as well as the segmentation process, the matching process, effort and cost. Therefore, it would be useful to be able to use a 2D single image to reconstruct the 3D heart surface model. We introduce an image-based human heart surface reconstruction from a single image as input. To model the surface of the heart, the proposed method, first, detects and corrects the specular reflection from the heart’s surface, which causes deformation of the surface in the R3. Second, it extrudes the three axes for each image pixel (e.g., x, y and z axes from the input image, in which the z-axis is calculated using the intensity value. Finally, a 3D reconstruction of the heart surface is created to help the novice cardiac surgeon to reduce the period of time in learning cardiac surgery and to enhance their perception of the operating theatre. The experimental results for images of the heart show the efficiency of the proposed method compared to the existing methods.

  16. Palliative Care, Hospice, and Advance Care Planning: Views of People Living with HIV and Other Chronic Conditions.

    Science.gov (United States)

    Slomka, Jacquelyn; Prince-Paul, Maryjo; Webel, Allison; Daly, Barbara J

    2016-01-01

    People living with HIV (PLWH) who survive to older adulthood risk developing multiple chronic medical conditions. Health policymakers recognize the role of early palliative care and advance care planning in improving health quality for at-risk populations, but misperceptions about palliative care, hospice, and advance care planning are common. Before testing a program of early palliative care for PLWH and other chronic conditions, we conducted focus groups to elicit perceptions of palliative care, hospice, and advance care planning in our target population. Overall, participants were unfamiliar with the term palliative care, confused concepts of palliative care and hospice, and/or associated hospice care with dying. Participants misunderstood advance care planning, but valued communication about health care preferences. Accepting palliative care was contingent on distinguishing it from hospice and historical memories of HIV and dying. Provision of high-quality, comprehensive care will require changing public perceptions and individuals' views in this high-risk population.

  17. Clinical compliance of viewing conditions in radiology reporting environments against current guidelines and standards

    Science.gov (United States)

    Daly, S.; Rainford, L.; Butler, M. L.

    2014-03-01

    Several studies have demonstrated the importance of environmental conditions in the radiology reporting environment, with many indicating that incorrect parameters could lead to error and misinterpretation. Literature is available with recommendations as to the levels that should be achieved in clinical practice, but evidence of adherence to these guidelines in radiology reporting environments is absent. This study audited the reporting environments of four teleradiologist and eight hospital based radiology reporting areas. This audit aimed to quantify adherence to guidelines and identify differences in the locations with respect to layout and design, monitor distance and angle as well as the ambient factors of the reporting environments. In line with international recommendations, an audit tool was designed to enquire in relation to the layout and design of reporting environments, monitor angle and distances used by radiologists when reporting, as well as the ambient factors such as noise, light and temperature. The review of conditions were carried out by the same independent auditor for consistency. The results obtained were compared against international standards and current research. Each radiology environment was given an overall compliance score to establish whether or not their environments were in line with recommended guidelines. Poor compliance to international recommendations and standards among radiology reporting environments was identified. Teleradiology reporting environments demonstrated greater compliance than hospital environments. The findings of this study identified a need for greater awareness of environmental and perceptual issues in the clinical setting. Further work involving a larger number of clinical centres is recommended.

  18. Rumen-degradable protein in roll conditioned or macerated legume hays and silages estimated by in situ kinetics vs. alternative methods

    Science.gov (United States)

    Alternatives to the in situ method for estimating rumen-degradable protein (RDP) in diverse forage legumes should be validated. In this study, RDP in roll conditioned or macerated silages and hays of Medicago, Lotus, and Trifolium species with differing polyphenol compositions were estimated from in...

  19. In-situ Ruminal Protein, Fiber, and Dry Matter Degradability of Legume Silages and Hays as Influenced by Protein-binding Polyphenols and Conditioning Methods

    Science.gov (United States)

    Conditioning and conservation methods may alter polyphenol binding in forage legumes and the degradability of crude protein (CP), neutral detergent fiber (NDF) and dry matter (DM) in the rumen. In this study, alfalfa, birdsfoot trefoil with 6 or 15 g/kg condensed tannins (CT), and red clover with ~1...

  20. Effect of reaction conditions on methyl red degradation mediated by boron and nitrogen doped TiO2

    Science.gov (United States)

    Galenda, A.; Crociani, L.; Habra, N. El; Favaro, M.; Natile, M. M.; Rossetto, G.

    2014-09-01

    Nowadays the employment of renewable and sustainable energy sources, and solar light as main option, becomes an urgent need. Photocatalytic processes received great attention in wastewater treatment due to their cheapness, environmental compatibility and optimal performances. Despite the general low selectivity of the photocatalysts, an accurate optimisation of the operational parameters needs to be carried out in order to maximise the process yield. Because of this reason, the present contribution aims to deepen either the knowledge in boron and/or nitrogen doped TiO2-based systems and their employment in methyl red removal from aqueous solutions. The samples were obtained by coprecipitation and characterised by XRD, SEM, BET specific surface area, UV-vis and XPS techniques. The catalytic activity was for the first time carefully evaluated with respect to methyl red photodegradation in different conditions as a function of working pH, counter-ions and pre-adsorption time. An ad-hoc study was performed on the importance of the pre-adsorption of the dye, suggesting that an extended adsorption is useless for the catalyst photoactivity, while a partial coverage is preferable. The photocatalytic tests demonstrate the positive influence of boron doping in photo-activated reactions and the great importance of the operational parameters with respect to the simple methyl red bleaching rather than the overall pollutant mineralisation. It is proved, indeed, that different working pH, acidifying means and substrate pre-adsorption time can enhance or limit the catalyst performances with respect to the complete pollutant degradation rather than its partial breakage.

  1. A finer view of the conditional galaxy luminosity function and magnitude-gap statistics

    Science.gov (United States)

    Trevisan, M.; Mamon, G. A.

    2017-10-01

    The gap between first- and second-ranked galaxy magnitudes in groups is often considered a tracer of their merger histories, which in turn may affect galaxy properties, and also serves to test galaxy luminosity functions (LFs). We remeasure the conditional luminosity function (CLF) of the Main Galaxy Sample of the SDSS in an appropriately cleaned subsample of groups from the Yang catalogue. We find that, at low group masses, our best-fitting CLF has steeper satellite high ends, yet higher ratios of characteristic satellite to central luminosities in comparison with the CLF of Yang et al. The observed fractions of groups with large and small magnitude gaps as well as the Tremaine & Richstone statistics are not compatible with either a single Schechter LF or with a Schechter-like satellite plus lognormal central LF. These gap statistics, which naturally depend on the size of the subsamples, and also on the maximum projected radius, Rmax, for defining the second brightest galaxy, can only be reproduced with two-component CLFs if we allow small gap groups to preferentially have two central galaxies, as expected when groups merge. Finally, we find that the trend of higher gap for higher group velocity dispersion, σv, at a given richness, discovered by Hearin et al., is strongly reduced when we consider σv in bins of richness, and virtually disappears when we use group mass instead of σv. This limits the applicability of gaps in refining cosmographic studies based on cluster counts.

  2. Evaluation of reversible and irreversible degradation rates of polymer electrolyte membrane fuel cells tested in automotive conditions

    Science.gov (United States)

    Gazdzick, Pawel; Mitzel, Jens; Garcia Sanchez, Daniel; Schulze, Mathias; Friedrich, K. Andreas

    2016-09-01

    This work provides single cell durability tests of membrane electrode assemblies in dynamic operation regularly interrupted by recovery procedures for the removal of reversible voltage losses. Degradation rates at different loads in one single test can be determined from these tests. Hence, it is possible to report degradation rates versus current density instead of a single degradation rate value. A clear discrimination between reversible and irreversible voltage loss rates is provided. The irreversible degradation rate can be described by a linear regression of voltage values after the recovery steps. Using voltage values before refresh is less adequate due to possible impacts of reversible effects. The reversible contribution to the voltage decay is dominated by an exponential decay after restart, eventually turning into a linear one. A linear-exponential function is proposed to fit the reversible voltage degradation. Due to this function, the degradation behavior of an automotive fuel cell can be described correctly during the first hours after restart. The fit parameters decay constant, exponential amplitude and linear slope are evaluated. Eventually, the reasons for the voltage recovery during shutdown are analyzed showing that ionomer effects in the catalyst layer and/or membrane seem to be the key factor in this process.

  3. Isolation and lipid degradation profile of Raoultella planticola strain 232-2 capable of efficiently catabolizing edible oils under acidic conditions.

    Science.gov (United States)

    Sugimori, Daisuke; Watanabe, Mika; Utsue, Tomohiro

    2013-01-01

    The lipids (fats and oils) degradation capabilities of soil microorganisms were investigated for possible application in treatment of lipids-contaminated wastewater. We isolated a strain of the bacterium Raoultella planticola strain 232-2 that is capable of efficiently catabolizing lipids under acidic conditions such as in grease traps in restaurants and food processing plants. The strain 232-2 efficiently catabolized a mixture (mixed lipids) of commercial vegetable oil, lard, and beef tallow (1:1:1, w/w/w) at 20-35 °C, pH 3-9, and 1,000-5,000 ppm lipid content. Highly effective degradation rate was observed at 35 °C and pH 4.0, and the 24-h degradation rate was 62.5 ± 10.5 % for 3,000 ppm mixed lipids. The 24-h degradation rate for 3,000 ppm commercial vegetable oil, lard, beef tallow, mixed lipids, and oleic acid was 71.8 %, 58.7 %, 56.1 %, 55.3 ± 8.5 %, and 91.9 % at pH 4 and 30 °C, respectively. R. planticola NBRC14939 (type strain) was also able to efficiently catabolize the lipids after repeated subculturing. The composition of the culture medium strongly influenced the degradation efficiency, with yeast extract supporting more complete dissimilation than BactoPeptone or beef extract. The acid tolerance of strain 232-2 is proposed to result from neutralization of the culture medium by urease-mediated decomposition of urea to NH(3). The rate of lipids degradation increased with the rates of neutralization and cell growth. Efficient lipids degradation using strain 232-2 has been achieved in the batch treatment of a restaurant wastewater.

  4. Transmutation of All German Transuranium under Nuclear Phase Out Conditions - Is This Feasible from Neutronic Point of View?

    Science.gov (United States)

    Merk, Bruno; Litskevich, Dzianis

    2015-01-01

    The German government has decided for the nuclear phase out, but a decision on a strategy for the management of the highly radioactive waste is not defined yet. Partitioning and Transmutation (P&T) could be considered as a technological option for the management of highly radioactive waste, therefore a wide study has been conducted. In the study group objectives for P&T and the boundary conditions of the phase out have been discussed. The fulfillment of the given objectives is analyzed from neutronics point of view using simulations of a molten salt reactor with fast neutron spectrum. It is shown that the efficient transmutation of all existing transuranium isotopes would be possible from neutronic point of view in a time frame of about 60 years. For this task three reactors of a mostly new technology would have to be developed and a twofold life cycle consisting of a transmuter operation and a deep burn phase would be required. A basic insight for the optimization of the time duration of the deep burn phase is given. Further on, a detailed balance of different isotopic inventories is given to allow a deeper understanding of the processes during transmutation in the molten salt fast reactor. The effect of modeling and simulation is investigated based on three different modeling strategies and two different code versions.

  5. Transmutation of All German Transuranium under Nuclear Phase Out Conditions – Is This Feasible from Neutronic Point of View?

    Science.gov (United States)

    Merk, Bruno; Litskevich, Dzianis

    2015-01-01

    The German government has decided for the nuclear phase out, but a decision on a strategy for the management of the highly radioactive waste is not defined yet. Partitioning and Transmutation (P&T) could be considered as a technological option for the management of highly radioactive waste, therefore a wide study has been conducted. In the study group objectives for P&T and the boundary conditions of the phase out have been discussed. The fulfillment of the given objectives is analyzed from neutronics point of view using simulations of a molten salt reactor with fast neutron spectrum. It is shown that the efficient transmutation of all existing transuranium isotopes would be possible from neutronic point of view in a time frame of about 60 years. For this task three reactors of a mostly new technology would have to be developed and a twofold life cycle consisting of a transmuter operation and a deep burn phase would be required. A basic insight for the optimization of the time duration of the deep burn phase is given. Further on, a detailed balance of different isotopic inventories is given to allow a deeper understanding of the processes during transmutation in the molten salt fast reactor. The effect of modeling and simulation is investigated based on three different modeling strategies and two different code versions. PMID:26717509

  6. Transmutation of All German Transuranium under Nuclear Phase Out Conditions - Is This Feasible from Neutronic Point of View?

    Directory of Open Access Journals (Sweden)

    Bruno Merk

    Full Text Available The German government has decided for the nuclear phase out, but a decision on a strategy for the management of the highly radioactive waste is not defined yet. Partitioning and Transmutation (P&T could be considered as a technological option for the management of highly radioactive waste, therefore a wide study has been conducted. In the study group objectives for P&T and the boundary conditions of the phase out have been discussed. The fulfillment of the given objectives is analyzed from neutronics point of view using simulations of a molten salt reactor with fast neutron spectrum. It is shown that the efficient transmutation of all existing transuranium isotopes would be possible from neutronic point of view in a time frame of about 60 years. For this task three reactors of a mostly new technology would have to be developed and a twofold life cycle consisting of a transmuter operation and a deep burn phase would be required. A basic insight for the optimization of the time duration of the deep burn phase is given. Further on, a detailed balance of different isotopic inventories is given to allow a deeper understanding of the processes during transmutation in the molten salt fast reactor. The effect of modeling and simulation is investigated based on three different modeling strategies and two different code versions.

  7. Relationship between cross-linking conditions of ethylene vinyl acetate and potential induced degradation for crystalline silicon photovoltaic modules

    Science.gov (United States)

    Jonai, Sachiko; Hara, Kohjiro; Tsutsui, Yuji; Nakahama, Hidenari; Masuda, Atsushi

    2015-08-01

    In this study, we investigated the relationship in crystalline silicon (c-Si) photovoltaic (PV) modules between the cross-linking level of copolymer of ethylene and vinyl acetate (EVA) as the encapsulant and the degree of degradation due to potential induced degradation (PID) phenomenon. We used three methods for the determination of cross-linking level of EVA: xylene method, which is one of the solvent extraction methods (SEM), curing degree by differential scanning calorimetry (DSC), and viscoelastic properties by dynamic mechanical analysis (DMA). The results indicate that degradation of PV modules by PID test depends on the cross-linking level of EVA. The PV modules encapsulated by EVA with higher cross-linking level show lower degradation degree due to PID phenomenon. Also we showed that EVA with higher cross-linking level tended to be higher volume resistivity. This tendency is similar to that for electrical resistance value during the PID test. The PID test was also done by changing thickness of EVA between front cover glass and c-Si with the same cross-linking level. The PV modules encapsulated by thicker EVA between front cover glass and c-Si cell show lower degradation by PID. From these results, the PV modules encapsulated by EVA with higher cross-linking level, higher volume resistivity and increased thickness would be tolerant of PID phenomenon.

  8. 赤霉酸降解菌的筛选及其适宜降解条件的确定%Screening of Gibberellic Acid-degrading Strains and the Optimization of Its Degradation Conditions

    Institute of Scientific and Technical Information of China (English)

    李清平; 马丽莉; 唐洁; 黄灏; 姚开

    2012-01-01

    [ Objective] To screen a gibberellic acid-degrading strain and investigate the optimization of its degradation conditions. [ Method] An efficient gibberellic acid-degrading strain G-6 was screened from some domesticated strains tolerant to gibberellic acid ( GA3) by using basal salt medium with gibberellic acid as its only carbon source. In this paper, the effects of various factors on GA3 degradation by G-6 were investigated by single factor test and its condition for GA3 degradation was determined. [ Kesuit] The rate of GA3 degradation was up to 60.62% when the strain was incubated in 250 ml conical flask containing 40 ml mineral medium with 200 mg/L of gibberellic acid, 5. 0% of bacterial suspension and pH 7,0 on a rotary shaker (140 r/min) at 30 X for 120 h. [ Conclusion] The research supplied references for the biodegrada-tion pathway of GA3.%[目的]筛选一株赤霉酸( GA3)降解菌并探讨其适宜的降解备件.[方法]利用仅含赤霉酸为唯一碳源的基础盐培养基,对前期驯化得到的对GA3具有较强耐受性的微生物进行筛选,获得了具有较强降解GA3能力的菌株G-6;采用单因素试验系统考察了不同因素对菌株G-6降解GA3效果的影响,确定了其适宜的降解条件.[结果]在培养时间为120h、培养温度为30℃、初始pH为7.0、接种量(菌悬液OD600=1.000)为5.0% (V/V)、培养基中赤霉酸浓度为200 mg/L、摇床转速为140 r/min、250 ml锥形瓶培养基装量为40 ml的条件下,GA3降解率达到60.62%.[结论]为深入探讨GA3的生物降解途径提供了参考.

  9. Biological degradation of triclocarban and triclosan in a soil under aerobic and anaerobic conditions and comparison with environmental fate modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ying Guangguo [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); CSIRO Land and Water, Adelaide Laboratory, PMB2, Glen Osmond SA 5064 (Australia)], E-mail: guang-guo.ying@gig.ac.cn; Yu Xiangyang [CSIRO Land and Water, Adelaide Laboratory, PMB2, Glen Osmond SA 5064 (Australia); Food Safety Research Institute, Jiangsu Academy of Agricultural Sciences, Nanjing 210014 (China); Kookana, Rai S. [CSIRO Land and Water, Adelaide Laboratory, PMB2, Glen Osmond SA 5064 (Australia)

    2007-12-15

    Triclocarban and triclosan are two antimicrobial agents widely used in many personal care products. Their biodegradation behaviour in soil was investigated by laboratory degradation experiments and environmental fate modelling. Quantitative structure-activity relationship (QSAR) analyses showed that triclocarban and triclosan had a tendency to partition into soil or sediment in the environment. Fate modelling suggests that either triclocarban or triclosan 'does not degrade fast' with its primary biodegradation half-life of 'weeks' and ultimate biodegradation half-life of 'months'. Laboratory experiments showed that triclocarban and triclosan were degraded in the aerobic soil with half-life of 108 days and 18 days, respectively. No negative effect of these two antimicrobial agents on soil microbial activity was observed in the aerobic soil samples during the experiments. But these two compounds persisted in the anaerobic soil within 70 days of the experimental period. - Triclocarban and triclosan can be degraded by microbial processes in aerobic soil, but will persist in anaerobic soil.

  10. The AirView Study: Comparison of Intubation Conditions and Ease between the Airtraq-AirView and the King Vision

    Directory of Open Access Journals (Sweden)

    Patrick Schoettker

    2015-01-01

    Full Text Available We conducted a study assessing the quality and speed of intubation between the Airtraq with its new iPhone AirView app and the King Vision in a manikin. The primary endpoint was reduction of time needed for intubation. Secondary endpoints included times necessary for intubation. 30 anaesthetists randomly performed 3 intubations with each device on a difficult airway manikin. Participants had a professional experience of 12 years: 60.0% possessed the Airtraq in their hospital, 46.7% the King Vision, and 20.0% both. Median time difference [IQR] to identify glottis (1.1 [−1.3; 3.9] P=0.019, for tube insertion (2.1 [−2.6; 9.4] P=0.002 and lung ventilation (2.8 [−2.4; 11.5] P=0.001, was shorter with the Airtraq-AirView. Median time for glottis visualization was significantly shorter with the Airtraq-AirView (5.3 [4.0; 8.4] versus 6.4 [4.6; 9.1]. Cormack Lehane before intubation was better with the King Vision (P=0.03; no difference was noted during intubation, for subjective device insertion or quality of epiglottis visualisation. Assessment of tracheal tube insertion was better with the Airtraq-AirView. The Airtraq-AirView allows faster identification of the landmarks and intubation in a difficult airway manikin, while clinical relevance remains to be studied. Anaesthetists assessed the intubation better with the Airtraq-AirView.

  11. The irradiating field of view of imaging laser radar under fog conditions in a controlled laboratory environment

    Science.gov (United States)

    Song, Wen-Hua; Ghassemlooy, Zabih; Lai, Jian-Cheng; Yan, Wei; Wang, Chun-Yong; Li, Zhen-Hua

    2017-04-01

    This paper theoretically and experimentally investigates the performance of the imaging laser radar (ILR) system under the fog condition. Fog is generated and controlled homogeneously within a dedicated indoor atmospheric chamber. A physical model of the reflected laser pulses due to fog and a standard Lambertian target are developed to determine the width of each echo pulse for different fog concentrations. We show that there is a good agreement between the predicted and measured results for the width of backscattered return pulses. Based on experimental results an empirical model of the horizontal and vertical irradiating field of views (FOVs) of ILR under different visibilities is also developed. Consequently, a new model is proposed to predict the horizontal and vertical irradiating FOVs of ILR by using the width of the backscattered return pulse under different fog conditions. The reported results can be used to dynamically adjust the scanning interval based on the variation of the irradiating FOVs of laser radar and improve the precision of target ranging and imaging.

  12. Combining the auxin-inducible degradation system with CRISPR/Cas9-based genome editing for the conditional depletion of endogenous Drosophila melanogaster proteins.

    Science.gov (United States)

    Bence, Melinda; Jankovics, Ferenc; Lukácsovich, Tamás; Erdélyi, Miklós

    2017-04-01

    Inducible protein degradation techniques have considerable advantages over classical genetic approaches, which generate loss-of-function phenotypes at the gene or mRNA level. The plant-derived auxin-inducible degradation system (AID) is a promising technique which enables the degradation of target proteins tagged with the AID motif in nonplant cells. Here, we present a detailed characterization of this method employed during the adult oogenesis of Drosophila. Furthermore, with the help of CRISPR/Cas9-based genome editing, we improve the utility of the AID system in the conditional elimination of endogenously expressed proteins. We demonstrate that the AID system induces efficient and reversible protein depletion of maternally provided proteins both in the ovary and the early embryo. Moreover, the AID system provides a fine spatiotemporal control of protein degradation and allows for the generation of different levels of protein knockdown in a well-regulated manner. These features of the AID system enable the unraveling of the discrete phenotypes of genes with highly complex functions. We utilized this system to generate a conditional loss-of-function allele which allows for the specific degradation of the Vasa protein without affecting its alternative splice variant (solo) and the vasa intronic gene (vig). With the help of this special allele, we demonstrate that dramatic decrease of Vasa protein in the vitellarium does not influence the completion of oogenesis as well as the establishment of proper anteroposterior and dorsoventral polarity in the developing oocyte. Our study suggests that both the localization and the translation of gurken mRNA in the vitellarium is independent from Vasa. © 2017 Federation of European Biochemical Societies.

  13. Pore-scale insights to the rate of organic carbon degradation and biofilm formation under variable hydro-biogeochemical conditions in soils and sediments

    Science.gov (United States)

    Liu, C.; Yan, Z.; Liu, Y.; Li, M.; Bailey, V. L.

    2015-12-01

    Biogeochemical processes that control microbial growth, organic carbon degradation, and CO2 production and migration are fundamentally occur at the pore scale. In this presentation, we will describe our recent results of a pore-scale simulation research to investigate: 1) how moisture content and distribution affects oxygen delivery, organic carbon availability, and microbial activities that regulate the rate of organic carbon degradation and CO2 production in aerobic systems; and 2) how pore-scale reactive transport processes affect local microbial growth, biofilm formation, and overall rate of microbial reactions in anoxic systems. The results revealed that there is an optimal moisture content for aerobic bacterial respiration and CO2 production. When moisture is below the optimal value, organic carbon availability limits its degradation due to diffusion and osmotic stress to bacterial reactivity; and when moisture is above the optimal value, oxygen delivery limits microbial respiration. The optimal moisture condition is, however, a function of soil texture and physical heterogeneity, bioavailable soil organic carbon, and microbial community function. In anoxic and saturated system, simulation results show that biofilm preferentially forms in concave areas around sand particles and macro aggregates where cross-directional fluxes of organic carbon and electron acceptors (e.g., nitrate) favor microbial growth and attachment. The results provide important insights to the establishment of constitutive relationships between the macroscopic rates of soil organic carbon degradation and moisture content, and to the development of biogeochemical reactive transport models that incorporate biofilm structures and physio-chemical heterogeneity in soils and sediments.

  14. Progressive activation of degradation processes in solid oxide fuel cells stacks: Part I: Lifetime extension by optimisation of the operating conditions

    Science.gov (United States)

    Nakajo, Arata; Mueller, Fabian; Brouwer, Jacob; Van herle, Jan; Favrat, Daniel

    2012-10-01

    The degradation of solid oxide fuel cells (SOFC) depends on stack and system design and operation. A methodology to evaluate synergistically these aspects to achieve the lowest production cost of electricity has not yet been developed. A repeating unit model, with as degradation processes the decrease in ionic conductivity of the electrolyte, metallic interconnect corrosion, anode nickel particles coarsening and cathode chromium contamination, is used to investigate the impact of the operating conditions on the lifetime of an SOFC system. It predicts acceleration of the degradation due to the sequential activation of multiple processes. The requirements for the highest system efficiency at start and at long-term differ. Among the selected degradation processes, those on the cathode side here dominate. Simulations suggest that operation at lower system specific power and higher stack temperature can extend the lifetime by a factor up to 10, because the beneficial decrease in cathode overpotential prevails over the higher release of volatile chromium species, faster metallic interconnect corrosion and higher thermodynamic risks of zirconate formation, for maximum SRU temperature below 1150 K. The counter-flow configuration, combined with the beneficial effect of internal reforming on lowering the parasitic air blower consumption, similarly yields longer lifetime than co-flow.

  15. Screening a Strain of Aspergillus niger and Optimization of Fermentation Conditions for Degradation of Aflatoxin B1

    OpenAIRE

    Wei Zhang; Beibei Xue; Mengmeng Li; Yang Mu; Zhihui Chen; Jianping Li; Anshan Shan

    2014-01-01

    Aflatoxin B1, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B1 after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis ...

  16. Unravelling the Interactions between Hydrolytic and Oxidative Enzymes in Degradation of Lignocellulosic Biomass by Sporothrix carnis under Various Fermentation Conditions

    Directory of Open Access Journals (Sweden)

    Olusola A. Ogunyewo

    2016-01-01

    Full Text Available The mechanism underlying the action of lignocellulolytic enzymes in biodegradation of lignocellulosic biomass remains unclear; hence, it is crucial to investigate enzymatic interactions involved in the process. In this study, degradation of corn cob by Sporothrix carnis and involvement of lignocellulolytic enzymes in biodegradation were investigated over 240 h cultivation period. About 60% degradation of corn cob was achieved by S. carnis at the end of fermentation. The yields of hydrolytic enzymes, cellulase and xylanase, were higher than oxidative enzymes, laccase and peroxidase, over 144 h fermentation period. Maximum yields of cellulase (854.4 U/mg and xylanase (789.6 U/mg were at 96 and 144 h, respectively. Laccase and peroxidase were produced cooperatively with maximum yields of 489.06 U/mg and 585.39 U/mg at 144 h. Drastic decline in production of cellulase at 144 h (242.01 U/mg and xylanase at 192 h (192.2 U/mg indicates that they play initial roles in biodegradation of lignocellulosic biomass while laccase and peroxidase play later roles. Optimal degradation of corn cob (76.6% and production of hydrolytic and oxidative enzymes were achieved with 2.5% inoculum at pH 6.0. Results suggest synergy in interactions between the hydrolytic and oxidative enzymes which can be optimized for improved biodegradation.

  17. Microbial population responses to pH and salt shock during phenols degradation under high salt conditions revealed by RISA and AFDRA.

    Science.gov (United States)

    Yan, Bin; Wang, Ping; Liao, Wenchao; Ye, Qian; Xu, Meilan; Zhou, Jiti

    2013-01-01

    The responses of microbial community to pH and salt shock during phenols degradation under high salt conditions were revealed by two DNA fingerprint methods, i.e. ribosomal intergenic spacer analysis (RISA) and amplified functional DNA restriction analysis (AFDRA), together with 16S rDNA clone library analysis. It was shown that the phenols removal rate was improved with increasing NaCl concentration from 0 to 50 mg/L, and could remain at a high level even in the presence of 100 mg/L NaCl. The degradation efficiency remained stable under neutral conditions (pH 7.0-9.0), but decreased sharply under acidic (below pH 5.0) or more alkaline conditions (above pH 10.0). The community structure was dramatically changed during salt fluctuations, with Halomonas sp. and Marinobacter sp. as the predominant salt-tolerant species. Meanwhile, Marinobacter sp. and Alcaligenes faecalis sp. were the major species which might play the key role for stabilizing the treatment systems under different pH conditions. Moreover, the changes of phenol hydroxylase genes were analyzed by AFDRA, which showed that these functional genes were substantially different under any shock conditions.

  18. 壬基酚降解菌的分离筛选及其降解条件的优化%Isolation, screening of NP-degrading bacteria and the optimization of degradation conditions

    Institute of Scientific and Technical Information of China (English)

    马娟; 杨芬; 唐玉斌; 陈芳艳; 王新刚

    2015-01-01

    In order to effectively control the NP-polluted water and enrich microbial resources of NP-degrading bacteria, two bacterial strains were isolated from the landfill leachate.The two NP-degrading bacteria, designat-ed strains SLY7 and SLY8.The morphology observation and 16S rDNA identification revealed that the two strains belonged to Pseudomonas stutzeri and Leclercia adecarboxylata, respectively.By shaking flasks tests, the effects of the conditions of degradation of NP by the strains was studied.SLY7 was determined that the optimum condi-tions were inoculum amount 3%, pH 8.0, and 30℃, on a shaker at 120 rpm for 3 d.Under these conditions, when the initial concentration was 10 mg/L, the degrading rate of NP reached 72.83%.SLY8 was determined that the optimum conditions were inoculum amount 5%, pH 7.0, and 35℃, on a shaker at 120 rpm.Under these conditions, the duration was 3 d, when the initial concentration was 5 mg/L, the degrading rate of NP reached 64.43%.%为了有效地对壬基酚( NP)污染水环境进行生物修复,丰富高效降解NP的微生物资源,从垃圾填埋场的垃圾渗滤液中,分离得到两株NP高效降解菌SLY7和SLY8,根据菌落的形态特征和16S rDNA序列分析,初步鉴定SLY7为施氏假单胞菌( Pseudomonas stutzeri) ,SLY8为非脱羧勒克菌( Leclercia adecarboxylata) .通过摇瓶实验考察NP的初始浓度、pH、温度以及投菌量等因素对菌株降解NP能力的影响.结果表明:菌株SLY7的最佳降解条件为温度30℃,pH为8.0,接种量3%( V/V),振荡速率120 r/min,在此条件下,历时3 d,对初始浓度为10 mg/L的NP的降解率可达72.83%;菌株SLY8的最佳降解条件为温度35℃,pH为7.0,接种量5%(V/V),振荡速率120 r/min,在此条件下,历时3 d,对初始浓度为5 mg/L的NP的降解率可达64.43%.

  19. 马尾藻岩藻聚糖硫酸酯降解工艺的研究%Study on the degradation conditions of fucoidan from Sargassum henslowianum

    Institute of Scientific and Technical Information of China (English)

    陈亚静; 王维民; 谌素华; 谢恩义

    2012-01-01

    The degradation of SF1 from Sargassum hemiphyllum was depended on ultrasound. Reducing sugar release was the indicator to reflect the relativity among ultrasound power,temperature and time during the degradation. Response surface methodology was used to optimize the degradation conditions, The result showed that the behavior of the system was explained by a quadratic equation between reducing sugar release and factors (ultrasonic power ,temperature and time). The result showed degradation conditions were ultrasonic power 350W,temperature 50℃ ,time 59min,and the reducing sugar release was 32.86ug/mL. Polysaccharide content,fucose content,sulfate group content and uronic acid of SF1' were 70.55% ,37.62%, 36.12% and 6.15%.%利用超声波降解法,以还原糖释放量为指标,对超声波功率、超声波时间及温度与多糖(马尾藻岩藻聚糖硫酸酯SF1)降解率的相关性进行分析,用响应面设计优化降解条件,建立了多糖降解率与超声波功率、时间和温度之间的二次回归模型。选择超声功率350W,温度50℃,时间59min,还原糖释放量为32.86ug/mL;降解后总糖含量为70.55%.岩藻糖含量为37.62%,硫酸根含量为36.12%,糖醛酸含量为6.15%。

  20. Development and validation of UV-spectrophotometric methods for the determination of sumatriptan succinate in bulk and pharmaceutical dosage form and its degradation behavior under varied stress conditions

    Directory of Open Access Journals (Sweden)

    Kudige Nagaraj Prashanth

    2014-04-01

    Full Text Available The aim of the present work is to develop sensitive, simple, accurate, precise and cost effective UV-spectrophotometric methods for the determination of sumatriptan succinate (STS, an anti-migraine drug, in bulk and pharmaceutical dosage form; and also to monitor the degradation behavior of the drug under different ICH prescribed stress conditions. Two methods were developed using different solvents, 0.1 M HCl (method A and acetonitrile (method B. The calibration graphs are linear over the range of 0.2–6.0 μg ml−1 in both the methods with a correlation coefficient (r of 0.9999. The apparent molar absorptivity values are 7.59 × 104 and 7.81 × 104 l mol−1 cm−1, for method A and method B, respectively. The other optical characteristics such as Sandell’s sensitivity, limit of detection (LOD and limit of quantification (LOQ values are also reported. The accuracy and precision of the methods were evaluated based on intra-day and inter-day variations. The accuracy of the methods was further confirmed by standard addition procedure. The degradation behavior of the drug was studied by subjecting STS to an acid and alkaline hydrolysis, oxidative, thermal and UV degradation. This study indicated that STS was degraded in alkaline medium and in oxidative condition. The proposed methods were successfully applied to the determination of STS in tablets and the results obtained are comparable with the official method.

  1. Novel Na2Mo4O13/α-MoO3 hybrid material as highly efficient CWAO catalyst for dye degradation at ambient conditions

    Science.gov (United States)

    Zhang, Zhang; Yang, Ruoyan; Gao, Yanshan; Zhao, Yufei; Wang, Junyang; Huang, Liang; Guo, Jiang; Zhou, Tuantuan; Lu, Peng; Guo, Zhanhu; Wang, Qiang

    2014-10-01

    We report a novel hybrid material Na2Mo4O13/α-MoO3 as highly efficient catalytic wet air oxidation (CWAO) catalyst, which showed the highest ever activity at room temperature and atmosphere pressure for the degradation of cationic red GTL. SEM and TEM analyses indicated that this hybrid catalyst has bamboo-shaped nanofiber morphology. In view of practical applications, the influence of some key parameters including operation temperature, catalyst calcination temperature, and the volume of dye wastewater have been optimized. The mechanism for the superior catalytic performance was investigated. XRD, XPS, and ESR suggested the Na2Mo4O13/α-MoO3 hybrid catalyst possesses more O2- ions in the oxygen deficient regions than neat α-MoO3, promoting the formation of active .OH radicals and resulting in a higher activity. Considering the facile preparation and its superior activity, this novel catalyst is promising for practical dye wastewater treatment.

  2. A simple and effective plating method to screen polycyclic aromatic hydrocarbon-degrading bacteria under various redox conditions.

    Science.gov (United States)

    Um, Youngsoon; Chang, Matthew Wook; Holoman, Tracey Pulliam

    2010-09-01

    Agar plates with a polycyclic aromatic hydrocarbon (PAH) layer have been used to screen for microorganisms that degrade PAHs, leaving clear zones around colonies; however, there are several problems with previous methods such as undesired contamination in the fume hood and difficulty in controlling the amount of PAH on the plates. In this study, we developed a modified screening method to address the drawbacks encountered with previous screening methods. A uniform white layer of PAHs was generated by spreading PAHs dissolved in volatile solvents over a surface of solidified agar medium, followed by the evaporation of the solvents. An inoculation was then performed by spreading a molten agar medium containing microbial samples over the solidified agar medium with a PAH layer. Subsequently, the white PAH layer migrated to the surface of the molten agar medium. This essential modification enabled us not only to solve problems of the previous screening methods but also to prepare an agar plate with a PAH layer without a complicated experimental scheme in the anaerobic chamber. After solidification of the molten agar medium and incubation of the plates, clear zones were successfully detected around colonies with aerobic and anaerobic PAH-degrading microbial cultures.

  3. Determination of degradation conditions of exchange resins containing technetium; Determinacion de condiciones de degradacion de resinas de intercambio conteniendo tecnecio

    Energy Technology Data Exchange (ETDEWEB)

    Rivera S, A.; Monroy G, F.; Quintero P, E., E-mail: aa_1190@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    The quantification of Tc-99 in spent exchange resins, coming from nuclear power plants, is indispensable to define their administration. The Tc-99 is a pure beta emitter of 210000 years of half-life, volatile and of a high mobility in water and soil. For this reason, the objective of this work is to establish a digestion method of ionic exchange resins containing technetium that retains more than 95% of this radioisotope. Mineralization tests were carried out of a resin Amberlite IRN-150 by means of an oxidation heat, in acid medium, varying the resin mass, the medium volume, the media type, the temperature and the digestion time. The digested samples were analyzed by gas chromatography to estimate the grade of their degradation. The {sup 99m}Tc was used as tracer to determine the technetium percentage recovered after mineralizing the resin. The digestion process depends on the temperature and the resin mass. At higher temperature better mineralization of samples and to greater resin mass to a constant temperature, less degradation of the resin. The spectra beta of the {sup 99m}Tc and {sup 99}Tc are presented. (Author)

  4. Effects of Extraction and Purification Methods on Degradation Kinetics and Stability of Lycopene from Watermelon under Storage Conditions.

    Science.gov (United States)

    Saeid, Abu; Eun, Jong Bang; Sagor, Md Shafiul Azam; Rahman, Atikur; Akter, Mst Sorifa; Ahmed, Maruf

    2016-09-28

    Lycopene was extraction, isolation and purification using recrystallization, column chromatography, and preparative thin layer chromatography (TLC) methods as well as degradation kinetics of lycopene were studied at refrigerated temperature and room temperature for 3 wk from watermelon. Higher lycopene degradation was observed at refrigerated temperature as compared to ambient temperature throughout the storage periods. The highest amount of lycopene retained in recrystallization (101.69 μg/g) followed by column chromatography (18.20 μg/g) and preparative TLC (15.57 μg/g). Color parameters, half-life time (t1/2 ), and color retention (%R) were dependent on extraction, isolation, and purification methods and storage life. Recrystallization and preparative TLC were followed by first order reaction model. Preparative TLC exhibited higher activation energy than did the recrystallization and column chromatography. Therefore, the result shows that recrystallization method could apply to extract and purify lycopene from watermelon that would also be used as a natural colorant as well as value-added product.

  5. Study on the Degradation Condition of Chitosan by Bromelain%菠萝蛋白酶降解壳聚糖条件的研究

    Institute of Scientific and Technical Information of China (English)

    黄甫; 黄利芬; 张晗

    2012-01-01

    [目的]为菠萝蛋白酶降解壳聚糖制备壳寡糖提供工艺参数和科学依据.[方法]用DNS比色法测定还原糖的含量,探讨不同条件对菠萝蛋白酶降解壳聚糖的影响.用端基分析法测定壳寡糖的分子量,研究菠萝蛋白酶降解壳聚糖过程中壳聚糖分子量的变化.[结果]菠萝蛋白酶降解壳聚糖的最适pH为7.1,最适温度为53℃,最适酶浓度为0.30 g/L.在最适条件下,降解反应进行6h以上,可以得到平均聚合度为8,平均分子量为1306的壳寡糖.[结论]菠萝蛋白酶能有效降解壳聚糖,制备壳寡糖.%[Objective] The aim was to provide scientific basis and process parameters for bromelain degradation of chitosan. [Method] The reducing sugar content was measured by the DNS colorimetric. The effects of different conditions on the degradation of chitosan were investigated. The chitooligosaccharides molecular weight was measured by End-group analysis method. The chitosan molecular weight change was studied in bromelain degradation of chitosan process. [ Result] The optimum pH value for degrading chitosan by this enzyme was 7. 1 and the optimum temperature was 53 t and the optimum enzyme concentration was 0. 30 g/L. After reaction for 6 hours, the chitooligosaccharides which the average degree of polymerization is 8, average molecular weight is 1 306 can be obtained under optimum conditions. [ Conclusion ] Chitosan can be effectively degraded by bromelain under optimum conditions.

  6. Inhomogeneous degradation of graphite anodes in automotive lithium ion batteries under low-temperature pulse cycling conditions

    Science.gov (United States)

    Burow, Daniel; Sergeeva, Kseniya; Calles, Simon; Schorb, Klaus; Börger, Alexander; Roth, Christina; Heitjans, Paul

    2016-03-01

    The aging of graphite anodes in prismatic lithium ion cells during a low temperature pulse charging regime was studied by electrical tests and post-mortem analysis. The capacity decrease and impedance increase mainly occurs in the beginning of cycling and lithium plating was identified as the major aging mechanism. The degradation and the local states of charge show an inhomogeneous distribution over the anode, which is confirmed from spatially resolved XRD studies and SEM combined with EDX performed on electrode cross sections. Comparing a charged cell with a discharged cell reveals that ca. 1/3 of the lithium is plated reversibly at the given SOH of 60%. It is proposed that high charge rates at low temperatures induce inhomogeneities of temperature and anode utilization resulting in inhomogeneous aging effects that accumulate over lifetime.

  7. Toxicity assessment of anatase and rutile titanium dioxide nanoparticles: The role of degradation in different pH conditions and light exposure.

    Science.gov (United States)

    De Matteis, Valeria; Cascione, Mariafrancesca; Brunetti, Virgilio; Toma, Chiara Cristina; Rinaldi, Rosaria

    2016-12-01

    Titanium dioxide nanoparticles (TiO2NPs), in the two crystalline forms, rutile and anatase, have been widely used in many industrial fields, especially in cosmetics. Therefore, a lot of details about their safety issues have been discussed by the scientific community. Many studies have led to a general agreement about TiO2NPs toxicity, in particular for anatase form, but no mechanism details have been proved yet. In this study, data confirm the different toxic potential of rutile and anatase TiO2NPs in two cell lines up to 5nM nanoparticles concentration. Moreover, we evaluated the role of titanium ions released by TiO2NPs in different conditions, at pH=4.5 (the typical lysosomal compartment pH) and at pH=5.5 (the skin physiological pH) in conditions of darkness and light, to mimic the dermal exposure of cosmetics. Anatase nanoparticles were proner to degradation both in the acidic conditions and at skin pH. Our study demonstrates that pH and sunlight are dominant factors to induce oxidative stress, TiO2NPs degradation and toxicity effects.

  8. DNA stable-isotope probing of oil sands tailings pond enrichment cultures reveals different key players for toluene degradation under methanogenic and sulfidogenic conditions.

    Science.gov (United States)

    Laban, Nidal Abu; Dao, Anh; Foght, Julia

    2015-05-01

    Oil sands tailings ponds are anaerobic repositories of fluid wastes produced by extraction of bitumen from oil sands ores. Diverse indigenous microbiota biodegrade hydrocarbons (including toluene) in situ, producing methane, carbon dioxide and/or hydrogen sulfide, depending on electron acceptor availability. Stable-isotope probing of cultures enriched from tailings associated specific taxa and functional genes to (13)C6- and (12)C7-toluene degradation under methanogenic and sulfate-reducing conditions. Total DNA was subjected to isopycnic ultracentrifugation followed by gradient fraction analysis using terminal restriction fragment length polymorphism (T-RFLP) and construction of 16S rRNA, benzylsuccinate synthase (bssA) and dissimilatory sulfite reductase (dsrB) gene clone libraries. T-RFLP analysis plus sequencing and in silico digestion of cloned taxonomic and functional genes revealed that Clostridiales, particularly Desulfosporosinus (136 bp T-RF) contained bssA genes and were key toluene degraders during methanogenesis dominated by Methanosaeta. Deltaproteobacterial Desulfobulbaceae (157 bp T-RF) became dominant under sulfidogenic conditions, likely because the Desulfosporosinus T-RF 136 apparently lacks dsrB and therefore, unlike its close relatives, is presumed incapable of dissimilatory sulfate reduction. We infer incomplete oxidation of toluene by Desulfosporosinus in syntrophic association with Methanosaeta under methanogenic conditions, and complete toluene oxidation by Desulfobulbaceae during sulfate reduction. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Application of {sup 13}C and {sup 15}N stable isotope probing to characterize RDX degrading microbial communities under different electron-accepting conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Kun-Ching; Lee, Do Gyun [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States); Fuller, Mark E.; Hatzinger, Paul B.; Condee, Charles W. [CB& I Federal Services, Lawrenceville, NJ (United States); Chu, Kung-Hui, E-mail: kchu@civil.tamu.edu [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States)

    2015-10-30

    Highlights: • SIP characterized RDX-degrading communities under different e-accepting conditions. • Dominant RDX degradation pathways differed under different e-accepting conditions. • More complete detoxification of RDX occurred under methanogenic and sulfate-reducing conditions than under manganese(IV) and iron(III)-reducing conditions. - Abstract: This study identified microorganisms capable of using the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) or its metabolites as carbon and/or nitrogen sources under different electron-accepting conditions using {sup 13}C and {sup 15}N stable isotope probing (SIP). Mesocosms were constructed using groundwater and aquifer solids from an RDX-contaminated aquifer. The mesocosms received succinate as a carbon source and one of four electron acceptors (nitrate, manganese(IV), iron(III), or sulfate) or no additional electron acceptor (to stimulate methanogenesis). When RDX degradation was observed, subsamples from each mesocosm were removed and amended with {sup 13}C{sub 3}- or ring-{sup 15}N{sub 3}-, nitro-{sup 15}N{sub 3}-, or fully-labeled {sup 15}N{sub 6}-RDX, followed by additional incubation and isolation of labeled nucleic acids. A total of fifteen 16S rRNA sequences, clustering in α- and γ-Proteobacteria, Clostridia, and Actinobacteria, were detected in the {sup 13}C-DNA fractions. A total of twenty seven sequences were derived from different {sup 15}N-DNA fractions, with the sequences clustered in α- and γ-Proteobacteria, and Clostridia. Interestingly, sequences identified as Desulfosporosinus sp. (in the Clostridia) were not only observed to incorporate the labeled {sup 13}C or {sup 15}N from labeled RDX, but also were detected under each of the different electron-accepting conditions. The data suggest that {sup 13}C- and {sup 15}N-SIP can be used to characterize microbial communities involved in RDX biodegradation, and that the dominant pathway of RDX biodegradation may differ under different

  10. Degradation of H3PO4/PBI High Temperature Polymer Electrolyte Membrane Fuel Cell under Stressed Operating Conditions

    DEFF Research Database (Denmark)

    Zhou, Fan

    . Given the current challenges for production and storage of the H2, it is more practical to use a liquid fuel such as methanol as the energy carrier. However, the reformate gas produced from methanol contains impurities such as CO, CO2 and unconverted methanol. For stationary applications, especially...... of the HT-PEM fuel cell are studied in the current work. Both in-situ and ex-situ characterization techniques are conducted to gain insight into the degradation mechanisms of the HT-PEM fuel cell under these operating conditions. The experimental results in this work suggest that the presence of methanol...

  11. EFFECT OF UN-DEGRADABLE PROTEIN SUPPLEMENTATION ON SEMEN QUALITY OF BUFFALO BULLS UNDER HEAT STRESS CONDITIONS

    Directory of Open Access Journals (Sweden)

    Shafqat Hussain, M.M. Siddiqui and G. Habib

    2002-04-01

    Full Text Available A study was conducted to investigate the effect of feeding un-degradable protein (UDP supplement on the semen quality of buffalo bulls during hot and humid part of summer season in Peshawar. Six Nili-Ravi buffalo bulls maintained at a semen production unit, Peshawar were randomly divided into two equal groups (control and treatment; Both groups were fed a basal diet of maize fodder ( 15 Kg/day/bull and wheat straw (6 Kg/day/bull. Bulls in the control group received 5 kg /day/head of a commercial concentrate while the treatment group was fed 3 Kg commercial concentrate and 1 Kg UDP supplement. Both supplements were iso-nitrogenous and provided 150g nitrogen /head/day. The diets were fed in a switch over design over two periods. Each period lasted for 32 days. One-week adaptation period was allowed at the start of each experimental period. In~sacco protein degradability at 12 hours incubation for commercial concentrate and UDP supplement was 72.87 and 43.46%, respectively. Mean ambient temperature, humidity and temperature-humidity-index were 32.01°C, 66.66% and 84.97, respectively: Semen volume of bulls in the control and treatment groups did not vary and averaged 6.87 ± 0.41 and 7.41 ± 0.56 mI/collection day with a mean sperm concentration of 1004.5 ± 69.06 and 969.14 ± 77.88 xI06/ml, respectively. Number, of defective sperms (head abl1ormalities, mid-piece defects, proximal droplet and tail defects in the control and treatment groups was not different. Feeding of UDP supplement did not influence the blood concentrations of calcium, phosphorus, urea al1d glucose. The absence of UDP effect on semen volume, and quality could be attributed to low thermal stress, feeding small quantity of UDP and less number of replicate bulls used in the present study.

  12. Laboratory degradation studies of 14C-atrazine and -isoproturon in soil from sugarcane cultivated fields under Kenyan tropical conditions.

    Science.gov (United States)

    Getenga, Z M; Dörfler, U; Schroll, R

    2009-06-01

    A study to compare the degradation rates of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diammine) and isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] in soils from sugarcane fields with different practices of herbicides application was carried out. (14)C-atrazine was poorly mineralized to (14)CO(2) (1.10% +/- 0.22%) after 139 days of incubation in soil without previous exposure to atrazine. In the same soil also with no previous isoproturon exposure isoproturon was mineralized to (14)CO(2) by 7.70% +/- 0.94%. Atrazine mineralization after 98 days was 13.4% +/- 0.30% in soil which discontinued the use of atrazine in 1997 while it was 89.9% +/- 1.23% in soil in which atrazine is currently being used. The isoproturon mineralization values were 7.24% +/- 0.85% and 22.97% +/- 0.96% in soil which discontinued atrazine and soil currently using atrazine, respectively.

  13. Ferrioxalate-assisted solar photo-Fenton degradation of a herbicide at pH conditions close to neutrality.

    Science.gov (United States)

    Conte, Leandro O; Schenone, Agustina V; Alfano, Orlando M

    2017-03-01

    The solar photo-Fenton degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution at a natural pH (pH = 5) using ferrioxalate as iron source was investigated. The kinetic model proposed and validated in a previous contribution was used to predict the reactants concentrations during the oxidation process in a non-concentrating pilot-plant solar reactor. The effects of hydrogen peroxide to 2,4-D initial concentration ratios (R), temperature, and radiation levels were studied. Furthermore, the spectral UV/visible and broadband solar radiation fluxes incident on the reactor window were evaluated by the Simple Model for the Atmospheric Radiative Transfer of Sunshine (SMARTS2) code. The complete destruction of 2,4-D and its main intermediate 2,4-dichlorophenol (2,4-DCP) was achieved in all the experimental runs in only 90 and 120 min of reaction, respectively. In agreement with these results, a reduction of toxicity in the system (expressed as % of inhibition of Vibrio fischeri) for longer times to 90 min of reaction was attained. It is important to emphasize the good agreement between kinetic model results and experimental data obtained.

  14. Quantitative analysis of genomic DNA degradation in whole blood under various storage conditions for molecular diagnostic testing.

    Science.gov (United States)

    Permenter, Jessalyn; Ishwar, Arjun; Rounsavall, Angie; Smith, Maddie; Faske, Jennifer; Sailey, Charles J; Alfaro, Maria P

    2015-12-01

    Proper storage of whole blood is crucial for isolating nucleic acids from leukocytes and to ensure adequate performance of downstream assays in the molecular diagnostic laboratory. Short-term and long-term storage recommendations are lacking for successful isolation of genomic DNA (gDNA). Container type (EDTA or heparin), temperature (4 °C and room temperature) and time (1-130 days) were assessed as criterion for sample acceptance policies. The percentage of integrated area (%Ti) between 150 and 10,000 bp from the 2200 TapeStation electropherogram was calculated to measure gDNA degradation. Refrigerated EDTA samples yielded gDNA with low %Ti (high quality). Heparinized samples stored at room temperature yielded gDNA of worst quality. Downstream analysis demonstrated that the quality of the gDNA correlated with the quality of the data; samples with high %Ti generated significantly lower levels of high molecular weight amplicons. Recommendations from these analyses include storing blood samples intended for nucleic acid isolation in EDTA tubes at 4 °C for long term storage (>10 days). gDNA should be extracted within 3 days when blood is stored at room temperature regardless of the container. Finally, refrigerated heparinized samples should not be stored longer than 9 days if expecting high quality gDNA isolates. Laboratories should consider many factors, in addition to the results obtained herein, to update their policies for sample acceptance for gDNA extraction intended for molecular genetic testing.

  15. Activation of persulfate by irradiated magnetite: implications for the degradation of phenol under heterogeneous photo-Fenton-like conditions.

    Science.gov (United States)

    Avetta, Paola; Pensato, Alessia; Minella, Marco; Malandrino, Mery; Maurino, Valter; Minero, Claudio; Hanna, Khalil; Vione, Davide

    2015-01-20

    We show that phenol can be effectively degraded by magnetite in the presence of persulfate (S2O8(2–)) under UVA irradiation. The process involves the radical SO4(–•), formed from S2O8(2–) in the presence of Fe(II). Although magnetite naturally contains Fe(II), the air-exposed oxide surface is fully oxidized to Fe(III) and irradiation is required to produce Fe(II). The magnetite + S2O8(2–) system was superior to the corresponding magnetite + H2O2 one in the presence of radical scavengers and in a natural water matrix, but it induced phenol mineralization in ultrapure water to a lesser extent. The leaching of Fe from the oxide surface was very limited, and much below the wastewater discharge limits. The reasonable performance of the magnetite/persulfate system in a natural water matrix and the low levels of dissolved Fe are potentially important for the removal of organic contaminants in wastewater.

  16. Degradation pattern of black phosphorus multilayer field-effect transistors in ambient conditions: Strategy for contact resistance engineering in BP transistors

    Science.gov (United States)

    Lee, Byung Chul; Kim, Chul Min; Jang, Ho-Kyun; Lee, Jae Woo; Joo, Min-Kyu; Kim, Gyu-Tae

    2017-10-01

    Black phosphorus (BP) has been proposed as a future optoelectronic material owing to its direct bandgap with excellent electrical performances. However, oxygen (O2) and water (H2O) molecules in an ambient condition can create undesired bubbles on the surface of the BP, resulting in hampering its excellent intrinsic properties. Here, we report the electrical degradation pattern of a mechanically exfoliated BP field-effect transistor (FET) in terms of the channel and contact, separately. Various electrical parameters such as the threshold voltage (VTH), carrier mobility (μ), contact resistance (RCT) and channel resistance (RCH) are estimated by the Y function method (YFM) with respect to time (up to 2000 min). It is found that RCT reduces and then, increases with time; whereas, the behavior of RCH is vice versa in ambient conditions. We attribute these effects to oxygen doping at the contact and the surface oxidation effects on the surface of the BP, respectively.

  17. Numerical analysis of head degrade law under cavitation condition of contra-rotating axial flow waterjet pump

    Science.gov (United States)

    Huang, D.; Pan, Z. Y.

    2015-01-01

    In order to study the flow-head characteristic curve, the SST turbulence model, homogeneous multiphase model and Rayleigh-Plesset equation were applied to simulate the cavitation characteristics in contra-rotating axial flow waterjet pump under different conditions based on ANSYS CFX software. The distribution of cavity, pressure coefficient of the blade at the design point under different cavitation conditions were obtained. The analysis results of flow field show that the vapour volume distribution on the impeller indicates that the vapour first appears at the leading edge of blade and then extends to the outlet of impeller with the reduction of Net Positive Suction Head Allowance (NPSHA). The present study illustrates that the main reason for the decline of the pump performance is the development of cavitation, and the simulation can truly reflect the cavitation performance of the contra-rotating axial flow waterjet pump.

  18. DOCUMENTATION OF NATIONAL WEATHER CONDITIONS AFFECTING LONG-TERM DEGRADATION OF COMMERCIAL SPENT NUCLEAR FUEL AND DOE SPENT NUCLEAR FUEL AND HIGH-LEVEL WASTE

    Energy Technology Data Exchange (ETDEWEB)

    W. L. Poe, Jr.; P.F. Wise

    1998-11-01

    The U.S. Department of Energy (DOE) is preparing a proposal to construct, operate 2nd monitor, and eventually close a repository at Yucca Mountain in Nye County, Nevada, for the geologic disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW). As part of this effort, DOE has prepared a viability assessment and an assessment of potential consequences that may exist if the repository is not constructed. The assessment of potential consequences if the repository is not constructed assumes that all SNF and HLW would be left at the generator sites. These include 72 commercial generator sites (three commercial facility pairs--Salem and Hope Creek, Fitzpatrick and Nine Mile Point, and Dresden and Morris--would share common storage due to their close proximity to each other) and five DOE sites across the country. DOE analyzed the environmental consequences of the effects of the continued storage of these materials at these sites in a report titled Continued Storage Analysis Report (CSAR; Reference 1 ) . The CSAR analysis includes a discussion of the degradation of these materials when exposed to the environment. This document describes the environmental parameters that influence the degradation analyzed in the CSAR. These include temperature, relative humidity, precipitation chemistry (pH and chemical composition), annual precipitation rates, annual number of rain-days, and annual freeze/thaw cycles. The document also tabulates weather conditions for each storage site, evaluates the degradation of concrete storage modules and vaults in different regions of the country, and provides a thermal analysis of commercial SNF in storage.

  19. Mn2+ alters peroxidase profiles and lignin degradation by the white-rot fungus Pleurotus ostreatus under different nutritional and growth conditions.

    Science.gov (United States)

    Cohen, Roni; Persky, Limor; Hazan-Eitan, Zahit; Yarden, Oded; Hadar, Yitzhak

    2002-01-01

    The white-rot fungus Pleurotus ostreatus produces two types of extracellular peroxidases: manganese-dependent peroxidase (MnP) and versatile peroxidase (VP). The effect of Mn2+ on fungal growth, peroxidase activity profiles, and lignin degradation by P. ostreatus was studied in liquid culture and under solid-state fermentation conditions on perlite, the latter resembling the natural growth conditions of this fungus. The fungus was grown in either a defined asparagine-containing basidiomycete selective medium (BSM) or in a rich peptone medium (PM). Biomass production, as determined by respiration experiments in solid-state fermentation and liquid cultures and fungal growth on Petri dishes, was higher in the PM than in the BSM. Mn2+ affected biomass production only in the PM on Petri dishes. In the nonamended PM, high levels of MnP and VP activity were detected relative to the nonamended BSM. Nevertheless, a higher rate of 14C-lignin mineralization was measured in the Mn2+-amended BSM, as determined during the course of 47 d of fermentation. Mn2+ amendment of the PM increased mineralization rate to that obtained in the Mn2+-amended BSM. The enzyme activity profiles of MnP and VP were studied in the BSM using anion-exchange chromatography. In the nonamended BSM, only minute levels of MnP and VP were detected. On Mn2+ amendment, two MnP isoenzymes (B1 and B2) appeared. Isoenzyme B2 was purified and showed 100% identity with the MnP isoenzyme purified in our previous study from PM-solid-state fermentation (P6). P6 was found to be the dominant isoenzyme in terms of activity level and gene expression compared with the VP isoenzymes. Based on these results, we concluded that Mn2+ plays a key role in lignin degradation under different nutritional and growth conditions, since it is required for the production of MnP in P. ostreatus.

  20. Dietary Cholesterol Concentration and Duration Degrade Long-Term Memory of Classical Conditioning of the Rabbit’s Nictitating Membrane Response

    Directory of Open Access Journals (Sweden)

    Bernard G. Schreurs

    2012-01-01

    Full Text Available A rabbit model of Alzheimer’s disease based on feeding a cholesterol diet for eight weeks shows sixteen hallmarks of the disease, including learning and memory changes. Although we have shown 2% cholesterol and copper in water can retard learning, other studies show feeding dietary cholesterol before learning can improve acquisition whereas feeding cholesterol after learning can degrade long-term memory. We explored this issue by manipulating cholesterol concentration and duration following classical trace conditioning of the rabbit’s nictitating membrane response and assessed conditioned responding after eight weeks on cholesterol. First, rabbits given trace classical conditioning followed by 0.5%, 1%, or 2% cholesterol for eight weeks showed body weight and serum cholesterol levels that were a function of dietary cholesterol. Although all concentrations of cholesterol showed some sign of retarding long-term memory, the level of memory retardation was correlated with serum cholesterol levels. Second, rabbits given trace conditioning followed by different durations of a 2% cholesterol diet combined with different durations of a 0% control diet for 8 weeks showed duration and timing of a 2% cholesterol diet were important in affecting recall. The data support the idea that dietary cholesterol may retard long-term memory.

  1. Effect of High Temperature Storage in Vacuum, Air, and Humid Conditions on Degradation of Gold/Aluminum Wire Bonds in PEMs

    Science.gov (United States)

    Teverovsky, Alexander

    2006-01-01

    Microcircuits encapsulated in three plastic package styles were stored in different environments at temperatures varying from 130 C to 225 C for up to 4,000 hours in some cases. To assess the effect of oxygen, the parts were aged at high temperatures in air and in vacuum chambers. The effect of humidity was evaluated during long-term highly accelerated temperature and humidity stress testing (HAST) at temperatures of 130 C and 150 C. High temperature storage testing of decapsulated microcircuits in air, vacuum, and HAST chambers was carried out to evaluate the role of molding compounds in the environmentally-induced degradation and failure of wire bonds (WB). This paper reports on accelerating factors of environment and molding compound on WB failures. It has been shown that all environments, including oxygen, moisture, and the presence of molding compounds reduce time-to-failures compared to unencapsulated devices in vacuum conditions. The mechanism of the environmental effect on KB degradation is discussed.

  2. Novel Na₂Mo₄O₁₃/α-MoO₃ hybrid material as highly efficient CWAO catalyst for dye degradation at ambient conditions.

    Science.gov (United States)

    Zhang, Zhang; Yang, Ruoyan; Gao, Yanshan; Zhao, Yufei; Wang, Junyang; Huang, Liang; Guo, Jiang; Zhou, Tuantuan; Lu, Peng; Guo, Zhanhu; Wang, Qiang

    2014-10-28

    We report a novel hybrid material Na2Mo4O13/α-MoO3 as highly efficient catalytic wet air oxidation (CWAO) catalyst, which showed the highest ever activity at room temperature and atmosphere pressure for the degradation of cationic red GTL. SEM and TEM analyses indicated that this hybrid catalyst has bamboo-shaped nanofiber morphology. In view of practical applications, the influence of some key parameters including operation temperature, catalyst calcination temperature, and the volume of dye wastewater have been optimized. The mechanism for the superior catalytic performance was investigated. XRD, XPS, and ESR suggested the Na2Mo4O13/α-MoO3 hybrid catalyst possesses more O(2-) ions in the oxygen deficient regions than neat α-MoO3, promoting the formation of active ·OH radicals and resulting in a higher activity. Considering the facile preparation and its superior activity, this novel catalyst is promising for practical dye wastewater treatment.

  3. 高效阿特拉津降解菌株DNS10降解条件优化%Optimization for degradation conditions of atrazine-degrading strain DNS10

    Institute of Scientific and Technical Information of China (English)

    张庆媛; 葛世杰; 姜昭; 王志刚; 张颖

    2013-01-01

    An atrazine-degrading strain, which grew with atrazine as the nitrogen source, was isolated from the top of black soil (0~10 cm) in cold area of long-term applying atrazine. The strain was designated as Ar-throbacter sp. DNS10 according to the sequence of 16S rRNA. It is capable of removing 100 mg/L atrazine in medium about 99. 41% within 24 h with 108 CFU/mL inoculation. The results of single factor analysis show the optimal conditions for growth and degradation ability of DNS 10. The range of temperature is 25 ~ 35℃ , pH is 5.0 ~8.0, medium salinity is 0. 1% ~2% and the maximum resistance concentration of atrazine is 1 200 mg/L. Furthermore, based on orthogonal experiments, the optimal combination scheme for the growth and degradation ability of DNS10 is that temperature is 30X1 , pH is 7. 5 and medium salinity is 0. 5% . The primary and secondary order of environmental factors that influence the degradation ability of DNS10 is that: temperature > salinity > pH.%从长期施用阿特拉津的寒地黑土耕层(0~10 cm)土壤中筛选到一株能以除草剂阿特拉津为氮源生长的降解菌株,结合16S rRNA序列分析结果,将该菌株命名为Arthrobacter sp.DNS10.在接种量为108 CFU/mL的条件下,菌株DNS10在24 h内对100 mg/L阿特拉津的降解率为99.41%.单因子实验结果表明,菌株DNS10适宜生长和降解的条件范围是:温度25 ~ 35℃,pH值5.0 ~8.0,培养液盐度0.1% ~2%,对阿特拉津最大耐受浓度可达1 200 mg/L.正交实验法进一步表明,该菌株保持较好生长及降解能力的最优方案是温度30℃,pH值7.5,培养液盐度0.5%.影响其降解能力的环境因素的主次顺序依次是:温度>盐度> pH值.

  4. Separating Mangrove Species and Conditions Using Laboratory Hyperspectral Data: A Case Study of a Degraded Mangrove Forest of the Mexican Pacific

    Directory of Open Access Journals (Sweden)

    Chunhua Zhang

    2014-11-01

    Full Text Available Given the scale and rate of mangrove loss globally, it is increasingly important to map and monitor mangrove forest health in a timely fashion. This study aims to identify the conditions of mangroves in a coastal lagoon south of the city of Mazatlán, Mexico, using proximal hyperspectral remote sensing techniques. The dominant mangrove species in this area includes the red (Rhizophora mangle, the black (Avicennia germinans and the white (Laguncularia racemosa mangrove. Moreover, large patches of poor condition black and red mangrove and healthy dwarf black mangrove are commonly found. Mangrove leaves were collected from this forest representing all of the aforementioned species and conditions. The leaves were then transported to a laboratory for spectral measurements using an ASD FieldSpec® 3 JR spectroradiometer (Analytical Spectral Devices, Inc., USA. R2 plot, principal components analysis and stepwise discriminant analyses were then used to select wavebands deemed most appropriate for further mangrove classification. Specifically, the wavebands at 520, 560, 650, 710, 760, 2100 and 2230 nm were selected, which correspond to chlorophyll absorption, red edge, starch, cellulose, nitrogen and protein regions of the spectrum. The classification and validation indicate that these wavebands are capable of identifying mangrove species and mangrove conditions common to this degraded forest with an overall accuracy and Khat coefficient higher than 90% and 0.9, respectively. Although lower in accuracy, the classifications of the stressed (poor condition and dwarf mangroves were found to be satisfactory with accuracies higher than 80%. The results of this study indicate that it could be possible to apply laboratory hyperspectral data for classifying mangroves, not only at the species level, but also according to their health conditions.

  5. Seismic soil–structure interaction analysis of a nuclear power plant building founded on soil and in degraded concrete stiffness condition

    Energy Technology Data Exchange (ETDEWEB)

    Farahani, Reza V., E-mail: reza.farahani@rizzoassoc.com; Dessalegn, Tewodros M., E-mail: tewodros.dessalegn@rizzoassoc.com; Vaidya, Nishikant R., E-mail: nish.vaidya@rizzoassoc.com; Bazan-Zurita, Enrique, E-mail: enrique.bazanz@rizzoassoc.com

    2016-02-15

    Highlights: • Three dimensional finite element modeling of a Nuclear Power Plant (NPP) building founded on soil is described. • A simplified technique to consider degraded stiffness of concrete members in seismic analysis of NPP buildings is presented. • The effect of subsurface profiles on the seismic response of a NPP building is investigated. - Abstract: This study describes three-dimensional (3-D) finite element (FE) modeling and seismic Soil-Structure Interaction (SSI) analysis of a Nuclear Power Plant (NPP) Diesel Generator Building (DGB) that is founded on soil in degraded concrete stiffness condition. A new technique is presented that uses two horizontal and vertical FE models to consider the concrete stiffness reduction of NPP buildings subjected to orthogonal ground motion excitations, in which appropriate stiffness reduction factors, based on the input motion orientation, are applied. Seismic SSI analysis is performed for each model separately, and dynamic responses are calculated in the three global directions. The results of the analysis for the two FE models are then combined, using the square-root-of-the-sum-of-squares (SRSS) combination rule. A sensitivity analysis is also performed to investigate the subsurface profile effect on the In-Structure (acceleration) Response Spectra (ISRS) of the building when subjected to site-specific Foundation Input Response Spectra (FIRS) that exhibit high spectral amplifications in the high-frequency range. The sensitivity analysis considers three strain-compatible subsurface profiles that represent Lower-Bound (LB), Best-Estimate (BE), and Upper-Bound (UB) conditions at the DGB site. The sensitivity analysis results indicate that the seismic response of the DGB founded on soil highly depends on the subsurface profile; i.e., each of the LB, BE, and UB subsurface profiles can maximize building seismic response when subjected to FIRS that exhibit high spectral amplifications in the high-frequency range

  6. Trametes meyenii possesses elevated dye degradation abilities under normal nutritional conditions compared to other white rot fungi.

    Science.gov (United States)

    Chenaux, Peter R; Lalji, Narisa; Lefebvre, Daniel D

    2014-01-01

    Several species of white-rot fungi were investigated for their utility in prolonged decolouration of the recalcitrant sulfonated azo dye, amaranth. Trametes pubescens, T. multicolor, T. meyenii and T. versicolor decoloured amaranth azo-dye best on low-nitrogen agar-solidified media whereas Bjerkandera adusta and Phlebia radiata were most effective in low nitrogen medium supplemented with manganese. Trametes cotonea did not decolour effectively under any condition. The decolouring Trametes species were also effective in liquid culture whereas B. adusta and P. radiata were not. Trametes meyenii, T. pubescens and T. multicolor were equal to or better than commonly employed T. versicolor at decolouring amaranth. This is the first study to show the dye decolouration potential of T. meyenii, T. pubescens, and T. multicolor. Supplementing with Mn(II) increased assayable manganese peroxidase activity, but not long-term decolouration, indicating that laccase is the main decolourizing enzyme in these Trametes species. This appears to be because of inadequate Mn(3+) chelation required by manganese peroxidase because adding relatively low amounts of malonate enhanced decolouration rates. The ability of Trametes meyenii to simultaneously decolour dye over prolonged periods of time while growing in relatively nutrient-rich medium appears to be unique amongst white-rot fungi, indicating its potential in wastewater bioremediation.

  7. How depositional conditions control input, composition, and degradation of organic matter in sediments from the Chilean coastal upwelling region

    DEFF Research Database (Denmark)

    Niggemann, Jutta; Ferdelman, Timothy G.; Lomstein, Bente Aagaard;

    2007-01-01

    In a comprehensive study, we compared depositional conditions, organic matter (OM) composition, and organic carbon turnover in sediments from two different depositional systems along the Chilean continental margin: at ~23°S off Antofagasta and at ~36°S off Concepción. Both sites lie within...... investigated for excess 210Pb (210Pbxs) activity, total organic and total inorganic carbon concentrations (TOC and TIC, respectively), C/N-ratios, organic carbon isotopic compositions (d13C), chlorin concentrations, Chlorin Indices (CI), and sulfate reduction rates (SRR). Sediment accumulation rates obtained...... from 210Pb-analysis were similar in both regions (0.04‑0.15 cm yr‑1 at 23°S, 0.10‑0.19 cm yr‑1 at 36°S), although total 210Pbxs fluxes indicated that the vertical particle flux was higher at 36°S than at 23°S. We propose that sediment focusing in isolated deposition centers led to high sediment...

  8. Complete anaerobic mineralization of pentachlorophenol (PCP) under continuous flow conditions by sequential combination of PCP-dechlorinating and phenol-degrading consortia.

    Science.gov (United States)

    Li, Zhiling; Yang, Suyin; Inoue, Yasushi; Yoshida, Naoko; Katayama, Arata

    2010-12-01

    Complete mineralization of 50 µM of pentachlorophenol (PCP) was achieved anaerobically under continuous flow conditions using two columns connected in series with a hydraulic retention time of 14.2 days, showing the highest reported mineralization rate yet of 3.5 µM day(-1). The first column, when injected with a reductive PCP dechlorinating consortium, dechlorinated PCP to mainly phenol and traces of 3-chlorophenol (3-CP) using lactate supplied continuously as an electron donor. The second column, with an anaerobic phenol degrading consortium, decomposed phenol and 3-CP under iron-reducing conditions with substantial fermentative degradation of organic compounds. When 20 mM of lactate was introduced into the first column, the phenol degradation activity of the second column was lost in a short period of time, because the amorphous Fe(III) oxide (FeOOH) that had been packed in the column before use was depleted by lactate metabolites, such as acetate and propionate, flowing into the second column from the first column. The complete mineralization of PCP was maintained for a long period by reducing the lactate concentration to 4 mM, effectively extending the longevity of second-column activity with no depletion of FeOOH for more than 200 pore volumes (corresponding to 3,000 days). The carbon balance showed that 50 µM PCP and 4 mM lactate in the influent had transformed to CO(2) (81%) and CH(4) (3%) and had contributed to biomass growth (8%). A comparison of the microbial consortia introduced into the columns and those flowing out from the columns suggested that the introduced population did not flow out during the experiments, although the microbial composition of the phenol column was considered to be affected by the inflow of microbes from the PCP dechlorination column. These results suggest that a sequential combination of reductive dechlorinating and anaerobic oxidizing consortia is useful for anaerobic remediation of chlorinated aromatic compounds in

  9. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  10. Photo-Fenton degradation of the herbicide 2,4-D in aqueous medium at pH conditions close to neutrality.

    Science.gov (United States)

    Conte, Leandro O; Schenone, Agustina V; Alfano, Orlando M

    2016-04-01

    A theoretical and experimental study of the photo-Fenton degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in water is presented. A kinetic model derived from a reaction sequence is proposed using the ferrioxalate complex as iron source for conditions of pH = 5. The kinetic model was employed to predict the concentrations of 2,4-D, 2,4-dichlorophenol (2,4-DCP), hydrogen peroxide (HP) and oxalate (Ox) in a flat plate laboratory reactor irradiated with a solar simulator. Two types of incident irradiation levels were tested by different combinations of attenuation filters. The effects of the oxalate/Fe(+3) molar ratio (Ox/Fe), the reaction temperature (T) and the 2,4-D/HP molar ratio (R) on the photo-Fenton process were also investigated. For low radiation level and operating conditions of R = 50 and T = 50 °C, a 2,4-D conversion of 95.6% was obtained after 180 min. Moreover, the 2,4-D conversion was almost 100% in only 120 min when the system was operated under the same operating conditions and high radiation level. From the proposed model and the experimental data, the corresponding kinetic parameters were estimated applying a nonlinear regression method. A good agreement between the kinetic model and experimental data, for a wide range of simulated solar operating conditions, was observed. For 2,4-D, 2,4-DCP, HP and Ox concentrations, the calculated RMSE were 1.21 × 10(-2), 5.45 × 10(-3), 2.86 × 10(-1) and 2.65 × 10(-2) mM, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Effect of extrusion conditions and hydrolysis with fiber-degrading enzymes on the production of C5 and C6 sugars from brewers’ spent grain for bioethanol production

    Directory of Open Access Journals (Sweden)

    Erick Heredia-Olea

    2015-03-01

    Full Text Available The bioconversion of brewers’ spent grain into bioethanol was investigated in the present study using thermoplastic extrusion and the use of fiber degrading enzymes. The extrusion conditions i.e. tempering moisture, screws speed, and temperature of last zone of the barrel were taken into account in order to optimize the yield of C5 and C6 sugars during the subsequent enzymatic hydrolysis step of the fibers. The most important variable that affected the sugar yield was the extrusion temperature, followed by the screws speed. The best extrusion conditions were 20% tempering moisture, 200 rpm and 50 °C. No enzymatic and yeast inhibitors were detected in any of the enzymatically-treated fiber hydrolyzates. The fermentation resulted in 5.43 mL bioethanol per 100g of extruded brewers’ spent grain (dry weight basis. The only sugar consumed was glucose. The free amino nitrogen amount quantified in the hydrolyzates was as low as >20 mg L-1, negatively affecting sugars consumption during the fermentation and consequently the ethanol yield.

  12. 降解棉秸秆耐热菌株的鉴定及降解条件优化%Identification of degradation cotton straw thermophilic strains and optimal degradate conditions

    Institute of Scientific and Technical Information of China (English)

    詹发强; 崔卫东; 周亚飞; 王炜

    2012-01-01

    [Objective] Two thermophilic fungal species which were isolated from the compost of cotton residue in Xinjiang were identified, and increased degradation rate of straw by optimizing the impact factors for cellulase production. [Methods] Two thermophilic fungal species were identified by morphological observation and analyzed the clone of the ITS gene fragment, The filter paper enzyme activity (FPA) of fungi was determined when they grown in a series of liquid state media containing pretreated natural cellulose as the carbon source, different nitrogen source, different initial pH, different inoculated amount and culture time, by analyzing the change of the FPA. [Results] Z1 is Aspergillus fumigatus Fresen and Z2 belongs to Myceliophthora Cost. (homology 97%). The filter paper enzyme activity (FPA) of fungi was determined when they grown in a series of liquid state media containing pretreated natural cellulose as the carbon source, different nitrogen source, different initial pH, different inocu-lated amount and culture time, by analyzing the change of the FPA, we had got the optimal conditions of fermentation. Under the optimal conditions, the decomposing (cotton residue) rate of Z1 was 10.19% and MS was 53.45% for 10 days, the decomposing (wheat straw) rate of Z2 was 27.50% for 10 days. [Conclusion] Degradation rate of straw MS better than single strains was more than half. It has great potential in recycling natural cellulose of Xinjiang when applied the fungal, which can degrade not only cotton residue but also wheat and rice straw, it has great potential for further apply in straw degradation.%[目的] 鉴定从新疆棉花秸秆高温堆肥中分离出的两株耐热真菌Z1、Z2的属种,并通过优化影响菌株产生纤维素酶的因素来提高菌株对秸秆的降解率.[方法] 经形态学和菌株的ITS区克隆与序列分析确定属种,以液体摇瓶发酵产滤纸酶活性(FPA)变化为衡量指标,对Z1、Z2以及二者混合菌(MS)的纤维

  13. Usefulness of a large field of view sensor for physicochemical, textural, and yield predictions under industrial goat cheese (Murcia al Vino) manufacturing conditions.

    Science.gov (United States)

    Rovira, S; García, V; Ferrandini, E; Carrión, J; Castillo, M; López, M B

    2012-11-01

    The applicability of a light backscatter sensor with a large field of view was tested for on-line monitoring of coagulation and syneresis in a goat cheese (Murcia al Vino) manufactured under industrial conditions. Cheesemaking was carried out concurrently in a 12-L pilot vat and a 10,000-L industrial vat following the normal cheesemaking protocol. Cheese moisture, whey fat content, hardness, springiness, and adhesiveness were measured during syneresis. The results obtained show that cutting time is best predicted by considering the coagulation ratio at the inflection point and the percentage increase in the ratio during coagulation, with no need for the first derivative. The large field of view reflectance ratio provided good results for the prediction of moisture content, yield, hardness, springiness, and adhesiveness of the final cheese. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. Observer performance in estimating upper arm elevation angles under ideal viewing conditions when assisted by posture matching software.

    Science.gov (United States)

    Jackson, Jennie A; Mathiassen, Svend Erik; Liv, Per

    2016-07-01

    Selecting a suitable body posture measurement method requires performance indices of candidate tools. Such data are lacking for observational assessments made at a high degree of resolution. The aim of this study was to determine the performance (bias and between- and within-observer variance) of novice observers estimating upper arm elevation postures assisted by posture matching software to the nearest degree from still images taken under ideal conditions. Estimates were minimally biased from true angles: the mean error across observers was less than 2°. Variance between observers was minimal. Considerable variance within observers, however, underlined the risk of relying on single observations. Observers were more proficient at estimating 0° and 90° postures, and less proficient at 60°. Thus, under ideal visual conditions observers, on average, proved proficient at high resolution posture estimates; further investigation is required to determine how non-optimal image conditions, as would be expected from occupational data, impact proficiency.

  15. Having views, abandoning views

    DEFF Research Database (Denmark)

    Sobisch, Jan-Ulrich

    2013-01-01

    In the bKa' brgyud tradition of Tibetan Buddhism, holding a philosophical view cannot produce an understanding of ultimate reality. The article contains some arguments why views must ultimately be abandoned....

  16. Having views, abandoning views

    DEFF Research Database (Denmark)

    Sobisch, Jan-Ulrich

    2013-01-01

    In the bKa' brgyud tradition of Tibetan Buddhism, holding a philosophical view cannot produce an understanding of ultimate reality. The article contains some arguments why views must ultimately be abandoned.......In the bKa' brgyud tradition of Tibetan Buddhism, holding a philosophical view cannot produce an understanding of ultimate reality. The article contains some arguments why views must ultimately be abandoned....

  17. Coping with difficult weather and snow conditions: Reindeer herders’ views on climate change impacts and coping strategies

    Directory of Open Access Journals (Sweden)

    Minna T. Turunen

    2016-01-01

    Full Text Available Winter is a critical season for reindeer herding, with the amount and quality of snow being among the most important factors determining the condition of reindeer and the annual success of the livelihood. Our first aim was to model the future (2035–2064 snow conditions in northern Finland, especially the quantities related to ground ice and/or ice layers within the snow pack, exceptionally deep snow and late snow melt. Secondly, we studied the strategies by which herders cope with the impacts of difficult weather and snow conditions on herding by interviewing 21 herders. SNOWPACK simulations indicate that snow cover formation will be delayed by an average of 19 days and snow will melt 16 days earlier during the period 2035–2064 when compared to 1980–2009. There will be more frequent occurrence of ground ice that persists through the winter and the ice layers in open environments will be thicker in the future. The snow cover will be 26–40% thinner and snow in open environments will be denser. Variability between winters will grow. In interviews, herders indicated that a longer snowless season and thin snow cover would be advantageous for herding due to increased availability of forage, but more frequent icing conditions would cause problems. The most immediate reaction of reindeer to the decreased availability of forage caused by difficult snow conditions is to disperse. This effect is intensified when the lichen biomass on the pastures is low. To cope with the impacts of adverse climatic conditions, herders increase control over their herds, intensify the use of pasture diversity, take reindeer into enclosures and/or start or intensify supplementary feeding. The research also reveals that predators, competing land uses and the high prices of supplementary feed and fuel were the major threats to the herders’ coping capacity. Coping capacity was facilitated by, among other factors, the herders’ experience-based traditional knowledge

  18. Synergistic degradation of arabinoxylan with alpha-L-arabinofuranosidase, xylanase and beta-xylosidase from soy sauce koji mold, Aspergillus oryzae, in high salt condition.

    Science.gov (United States)

    Hashimoto, Tadaaki; Nakata, Yoshiyuki

    2003-01-01

    This study addresses induction and some properties of alpha-L-arabinofuranosidase from a soy sauce koji mold, Aspergillus oryzae HL15, cultured on solid and liquid media. Alpha-L-arabinofuranosidase was induced by soybean polysaccharide and secreted into media on solid cultivation; the enzyme was associated with mycelium as a cell-wall-bound form in liquid cultivation. A major alpha-L-arabinofuranosidase, which was purified homogeneously on SDS-PAGE, showed highest activity in the presence of 10% of NaCl; also, somewhat higher activity was observed even in 25% NaCl than in the absence of NaCl. Arabinoxylan was synergistically degraded by xylanase, beta-xylosidase, and alpha-L-arabinofuranosidase from A. oryzae HL15 in the condition of imitative pH 5.0 and 15% NaCl concentration of the soy sauce moromi mash. These results suggest that arabinose and xylose, which are closely related to melanoidin formation, can be released by synergistic action of these enzymes in soy sauce moromi mash.

  19. Research on Fermentation Condition of Lutein Degradation Bacterium from Tobacco%烟叶叶黄素降解菌发酵条件研究

    Institute of Scientific and Technical Information of China (English)

    杨雪鹏; 赵越; 胡仙妹; 马科; 毛多斌

    2015-01-01

    为探讨烟叶中叶黄素生物降解的方法,利用单因素试验和响应面分析法对叶黄素降解酶高产菌株Ewingella americana(Y32)的液体发酵工艺条件进行优化。结果表明,最适的碳源、氮源和无机盐分别为葡萄糖、酵母膏和KH2 PO4。在单因素试验的基础上,采用Box-Behnken试验设计进行回归分析得到最优培养基组成为:葡萄糖1.38%、酵母膏0.48%、KH2 PO40.19%,在该条件下叶黄素降解率为90.02%,与理论预测值(89.55%)基本吻合,比优化前的基础发酵培养基提高45.07%。%Optimization of lutein degradation enzyme production by Ewingella americana ( Y32 ) was investigated by response surface analysis methodology. First,the one-factor-at-a-time method was adopted to investigate the effects of variable of medium components( i. e. ,carbon, nitrogen,and mineral sources) on the enzyme production. Among these variables, glucose,yeast extract and KH2 PO4 were identified to be the most suitable carbon,nitrogen and inorganic salt,respectively. Subsequently,the concentration of glucose,yeast extract and KH2 PO4 were optimized using Box-Behnken regression analysis method. The optimal composition was found to be glucose 1. 38%, yeast extract 0. 48%, KH2 PO4 0. 19%. Under optimal culture conditions,the maximum degradation rate of lutein was 90. 02%,which was increased by 45. 07% compared with that before optimization. The experimental value was in according with that of predicting.

  20. Stability and Degradation of Caffeoylquinic Acids under Different Storage Conditions Studied by High-Performance Liquid Chromatography with Photo Diode Array Detection and High-Performance Liquid Chromatography with Electrospray Ionization Collision-Induced Dissociation Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Meng Xue

    2016-07-01

    Full Text Available Caffeoylquinic acids (CQAs are main constituents in many herbal medicines with various biological and pharmacological effects. However, CQAs will degrade or isomerize when affected by temperature, pH, light, etc. In this study, high-performance liquid chromatography with photodiode array detection (HPLC-PDA and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS was utilized to study the stability and degradation of CQAs (three mono-acyl CQAs and four di-acyl CQAs under various ordinary storage conditions (involving different temperatures, solvents, and light irradiation. The results indicated that the stability of CQAs was mainly affected by temperature and light irradiation, while solvents did not affect it in any obvious way under the conditions studied. Mono-acyl CQAs were generally much more stable than di-acyl CQAs under the same conditions. Meanwhile, the chemical structures of 30 degradation products were also characterized by HPLC-MSn, inferring that isomerization, methylation, and hydrolysis were three major degradation pathways. The result provides a meaningful clue for the storage conditions of CQAs standard substances and samples.

  1. Degradation of {gamma}-HCH spiked soil using stabilized Pd/Fe{sup 0} bimetallic nanoparticles: Pathways, kinetics and effect of reaction conditions

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ritu [Ecotoxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Lucknow 226 025, UP (India); Misra, Virendra, E-mail: virendra_misra2001@yahoo.co.in [Ecotoxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Mudiam, Mohana Krishna Reddy [Analytical Chemistry Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Chauhan, Lalit Kumar Singh [Petroleum Toxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow 226 001, UP (India); Singh, Rana Pratap [Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Raebareli Road, Lucknow 226 025, UP (India)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer This study explores the potential of CMC-Pd/nFe{sup 0} to degrade {gamma}-HCH in spiked soil. Black-Right-Pointing-Pointer Sorption-desorption characteristics and partitioning of {gamma}-HCH is investigated. Black-Right-Pointing-Pointer Three degradation pathways has been proposed and discussed. Black-Right-Pointing-Pointer {gamma}-HCH degradation mechanism and kinetics is elucidated. Black-Right-Pointing-Pointer Activation energy reveals that {gamma}-HCH degradation is a surface mediated reaction. - Abstract: This study investigates the degradation pathway of gamma-hexachlorocyclohexane ({gamma}-HCH) in spiked soil using carboxymethyl cellulose stabilized Pd/Fe{sup 0} bimetallic nanoparticles (CMC-Pd/nFe{sup 0}). GC-MS analysis of {gamma}-HCH degradation products showed the formation of pentachlorocyclohexene, tri- and di-chlorobenzene as intermediate products while benzene was formed as the most stable end product. On the basis of identified intermediates and final products, degradation pathway of {gamma}-HCH has been proposed. Batch studies showed complete {gamma}-HCH degradation at a loading of 0.20 g/L CMC-Pd/nFe{sup 0} within 6 h of incubation. The surface area normalized rate constant (k{sub SA}) was found to be 7.6 Multiplication-Sign 10{sup -2} L min{sup -1} m{sup -2}. CMC-Pd/nFe{sup 0} displayed {approx}7-fold greater efficiency for {gamma}-HCH degradation in comparison to Fe{sup 0} nanoparticles (nFe{sup 0}), synthesized without CMC and Pd. Further studies showed that increase in CMC-Pd/nFe{sup 0} loading and reaction temperature facilitates {gamma}-HCH degradation, whereas a declining trend in degradation was noticed with the increase in pH, initial {gamma}-HCH concentration and in the presence of cations. The data on activation energy (33.7 kJ/mol) suggests that {gamma}-HCH degradation is a surface mediated reaction. The significance of the study with respect to remediation of {gamma}-HCH contaminated soil using

  2. Use of factorial design for evaluation of plasma conditions and comparison of two liquid sample introduction systems for an axially viewed inductively coupled plasma optical emission spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Trevizan, Lilian C. [Grupo de Analise Instrumental Aplicada, Departamento de Quimica, Universidade Federal de Sao Carlos, Caixa Postal 676, Sao Carlos, SP, 13650-970 (Brazil); Vieira, Edivan C. [Grupo de Analise Instrumental Aplicada, Departamento de Quimica, Universidade Federal de Sao Carlos, Caixa Postal 676, Sao Carlos, SP, 13650-970 (Brazil); Embrapa Pecuaria Sudeste, Sao Carlos, SP (Brazil); Nogueira, Ana Rita A. [Embrapa Pecuaria Sudeste, Sao Carlos, SP (Brazil); Nobrega, Joaquim A. [Grupo de Analise Instrumental Aplicada, Departamento de Quimica, Universidade Federal de Sao Carlos, Caixa Postal 676, Sao Carlos, SP, 13650-970 (Brazil)]. E-mail: djan@terra.com.br

    2005-06-30

    A factorial design was applied to evaluate plasma conditions employing the Mg II 280/Mg I 285 nm intensity ratio in an axially viewed inductively coupled plasma optical emission spectrometer using different sample introduction devices: a concentric or a V-groove nebulizer and a cyclonic or a Sturman-Masters spray chamber. Effects of nebulizer gas flow-rate on Mg II/Mg I ratio were different in each introduction system. Robust conditions were obtained at low nebulizer gas flow-rate when using concentric nebulizer with a cyclonic spray chamber or a concentric nebulizer and a Sturman-Masters spray chamber. However, when using a V-groove nebulizer with a Sturman-Masters spray chamber, Mg II/Mg I ratio increased at high nebulizer gas flow-rates. Recovery experiments for a milk standard reference material diluted in water-soluble tertiary amines in both robust and non-robust conditions indicated that the robust condition was reached at higher nebulizer gas flow-rates and led to better accuracy and precision when using a V-groove nebulizer.

  3. Diagnostic accuracy of carious lesions in digital radiographs at a public dental clinic - can it be improved by optimizing viewing conditions and further education?.

    Science.gov (United States)

    Milosavljevic, Aleksandar; Westerberg, Jane; Hellén-Halme, Kristina

    2016-01-01

    This study investigated the diagnostic accuracy of digital dental radiograpny for detecting carious lesions on approximal surfaces before and after optimization of the environ- ment, and after joint training on evaluation and review of x-rays. A further aim was to evaluate differences in diagnostic accuracy between general dental practitioners (GDPs) and dental hygienists (DHs). One hundred extracted teeth (premolars and molars) underwent standardized radiography. Eleven participants (seven GDPs and four DHs) evaluated digital images for approximal carious lesions in three sessions: (1) at current conditions with no optimization or further training, (2) under optimized viewing conditions, and (3) under optimized viewing conditions after a short educational session. Receiver operating characteristic curves were,used to evaluate the results. Histological evaluation was made and served as a cri- terion standard for differentiating sound teeth and teeth with carious lesions. Kappa statistics evaluated intra-observer agreement. Diagnostic accuracy in the GDP group differed sig- nificantlyfor all types of carious lesions between the first and third evaluations (p=0.002), and also between the second and third (p=0.015). Diagnostic accuracy also differed significantly for carious lesions into the dentin between the first and third evaluations (p=0.010) and between the second and third (p=0.015). Most of the staff had optimized the environment when evaluating digital radiographs. A short educational session highlighting the difficulty of caries diagnostics in digital dental radiography can increase diagnostic accuracy. Diagnostic accuracy in the detection of approximal carious lesions on digital radiographs did not differ between GDPs and DHs.

  4. Research on the Optimum Degradation Conditions of Atrazine by White Rot Fungi Laccase%白腐菌漆酶对莠去津最适降解条件的探讨

    Institute of Scientific and Technical Information of China (English)

    程科; 毕云枫; 沈明浩

    2012-01-01

    [目的]将白腐菌Coprinopsis cinerea okayama 7#130漆酶对三嗪类农药莠去津的降解条件进行了研究.[方法]向纯漆酶溶液中加入一定浓度的莠去津溶液进行降解反应,采用HPLC测定其含量,计算降解率.利用Box-Behnken设计对影响降解此农药的关键因素进行优化.[结果]经Design-Expert软件二次回归分析,得到莠去津降解的最适条件:pH值为6.9,温度为38.3℃,反应体系体积为5.3 mL,转速为186 r/min.在此条件下,莠去津降解率响应预测值为52.41%,验证值为52.32%.[结论]最适条件下的降解率提高了10%~15%,这为降低莠去津对环境的危害提供了科学依据.%[Aims] The degradation conditions of triazine pesticide atrazine by white-rot fungi Coprinopsis cinerea okayama7# 130 laccase were studied. [Methods] Some certain concentration of atrazine was added to the pure laccase solution before the degradation. The HPLC was performed to determine the content, and then the degradation rate was calculated. The key factors influencing the degradation of atrazine were optimized by Box-Behnken design. [Results] The result was undertaken by the second regression analysis using Design-Expert software, which showed that the optimal condition of the atrazine degrading was as follows: The pH value was 6.9, the temperature was 38.3 °C, the reaction volume was 5.3 mL, and the shaking speed was 186 r/min respectively. Under the optimal condition, the predicted value of the atrazine degradation rate was 52.41%, and the experimental value of atrazine degradation rate was 52.32%. [Conclusions] The degradation rate increased by 10-15% under the optimal condition, which provided the scientific basis to reduce the harm to the environment caused by atrazine.

  5. Microbial aerobic and anaerobic degradation of acrylamide in sludge and water under environmental conditions--case study in a sand and gravel quarry.

    Science.gov (United States)

    Guezennec, A G; Michel, C; Ozturk, S; Togola, A; Guzzo, J; Desroche, N

    2015-05-01

    Polyacrylamides (PAMs) are used in sand and gravel quarries as water purification flocculants for recycling process water in a recycling loop system where the flocculants remove fine particles in the form of sludge. The PAM-based flocculants, however, contain residual amounts of acrylamide (AMD) that did not react during the polymerization process. This acrylamide is released into the environment when the sludge is discharged into a settling basin. Here, we explore the microbial diversity and the potential for AMD biodegradation in water and sludge samples collected in a quarry site submitted to low AMD concentrations. The microbial diversity, analyzed by culture-dependent methods and the denaturing gradient gel electrophoresis approach, reveals the presence of Proteobacteria, Cyanobacteria, and Actinobacteria, among which some species are known to have an AMD biodegradation activity. Results also show that the two main parts of the water recycling loop-the washing process and the settling basin-display significantly different bacterial profiles. The exposure time with residual AMD could, thus, be one of the parameters that lead to a selection of specific bacterial species. AMD degradation experiments with 0.5 g L(-1) AMD showed a high potential for biodegradation in all parts of the washing process, except the make-up water. The AMD biodegradation potential in samples collected from the washing process and settling basin was also analyzed taking into account on-site conditions: low (12 °C) and high (25 °C) temperatures reflecting the winter and summer seasons, and AMD concentrations of 50 μg L(-1). Batch tests showed rapid (as little as 18 h) AMD biodegradation under aerobic and anaerobic conditions at both the winter and summer temperatures, although there was a greater lag time before activity started with the AMD biodegradation at 12 °C. This study, thus, demonstrates that bacteria present in sludge and water samples exert an in situ and rapid

  6. Children and young people's views on access to a web-based application to support personal management of long-term conditions: a qualitative study.

    Science.gov (United States)

    Huby, K; Swallow, V; Smith, T; Carolan, I

    2017-01-01

    An exploration of children and young people's views on a proposed web-based application to support personal management of chronic kidney disease at home is important for developing resources that meet their needs and preferences. As part of a wider study to develop and evaluate a web-based information and support application for parents managing their child's chronic kidney disease, qualitative interviews were conducted with 26 children and young people aged 5-17 years. Interviews explored their views on content of a proposed child and young person-appropriate application to support personal management of their condition. Data were analysed by using framework technique and self-efficacy theory. One overarching theme of Access and three subthemes (information, accessibility and normalization) were identified. Information needed to be clear and accurate, age appropriate and secure. Access to Wi-Fi was essential to utilize information and retain contact with peers. For some, it was important to feel 'normal' and so they would choose not to access any care information when outside of the hospital as this reduced their ability to feel normal. Developing a web-based application that meets children and young peoples' information and support needs will maximize its utility and enhance the effectiveness of home-based clinical caregiving, therefore contributing to improved outcomes for patients. © 2016 John Wiley & Sons Ltd.

  7. 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.

  8. Motor degradation prediction methods

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  9. Effect of the position of the visible sky in determining the sky view factor on micrometeorological and human thermal comfort conditions in urban street canyons

    Science.gov (United States)

    Qaid, Adeb; Lamit, Hasanuddin Bin; Ossen, Dilshan Remaz; Rasidi, Mohd Hisyam

    2017-01-01

    Poor daytime and night-time micrometeorological conditions are issues that influence the quality of environmental conditions and can undermine a comfortable human lifestyle. The sky view factor (SVF) is one of the essential physical parameters used to assess the micrometeorological conditions and thermal comfort levels within city streets. The position of the visible sky relative to the path of the sun, in the cardinal and ordinal directions, has not been widely discerned as a parameter that could have an impact on the micrometeorological conditions of urban streets. To investigate this parameter, different urban streets that have a similar SVF value but diverse positions of visible sky were proposed in different street directions intersecting with the path of the sun, namely N-S, NE-SW and NW-SE. The effects of daytime and night-time micrometeorological variables and human thermal comfort variables on the street were investigated by applying ENVI-met V3.1 Beta software. The results show that the position of the visible sky has a greater influence on the street's meteorological and human thermal comfort conditions than the SVF value. It has the ability to maximise or minimise the mean radiation temperature (Tmrt, °C) and the physiological equivalent temperature (PET, °C) at street level. However, the visible sky positioned to the zenith in a NE-SW or N-S street direction and to the SW of a NW-SE street direction achieves the best daytime micrometeorological and thermal comfort conditions. Alternatively, the visible sky positioned to the NE for a NW-SE street direction, to the NW and the zenith for a NE-SW street direction and to the zenith for a N-S street direction reduces the night-time air temperature (Ta, °C). Therefore, SVF and the position of the visible sky relative to the sun's trajectory, in the cardinal and ordinal directions, must be considered during urban street planning to better understand the resultant micrometeorological and human thermal

  10. Environmental degradation in biocomposites

    CSIR Research Space (South Africa)

    John, Maya J

    2017-06-01

    Full Text Available molecular chain scission, surface oxidation, and breakdown of molecules to form active radicals. The main degradation processes occurring by weathering includes photoradiation, thermal degradation, photooxidation, and hydrolysis [22,23]. The effect... which exhibits transitions from glassy stage to a rubbery stage at its glass transition temperature. ● Weathering Composites commonly used in automotive and aerospace applications are subjected to varying conditions of sunlight, rain, moisture...

  11. A validated stability-indicating RP-LC method for the simultaneous determination of amlodipine and perindopril in tablet dosage form and their stress degradation behavior under ICH-recommended stress conditions.

    Science.gov (United States)

    Gumustas, Mehmet; Ozkan, Sibel A

    2013-01-01

    A stability-indicating RP-LC assay method was developed for the simultaneous determination of the cardiovascular drugs amlodipine and perindopril in the presence of degradation products generated from forced decomposition studies. The developed method is applicable for the determination of related substances in bulk drugs and simultaneous assay in a tablet pharmaceutical dosage form. Separation of the drugs and their degradation products was obtained using an RP Waters Spherisorb ODS1 column (250 x 4.6 mm id, 5 pm particle size) with the mobile phase acetonitrile-water (30 + 70, v/v) containing 15 mM phosphoric acid. The pH of the mobile phase was adjusted to 5.0. A flow rate of 1.2 mL/min was used for the separations, with detection at 215 nm. The chromatographic separation was performed at a column temperature of 45 degrees C. Atenolol was chosen as the internal standard. Amlodipine and perindopril were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Degradation studies showed that both compounds were degraded under these stress conditions. The method was found to be stability-indicating and can be used for the routine analysis of amlodipine and perindopril in the studied combined tablet dosage form.

  12. LabVIEW aplicado al diagnóstico de estado en tiempo real de transformadores de potencia LabVIEW apply to diagnostic that assess the condition in real time of the power transformers

    Directory of Open Access Journals (Sweden)

    Eliezer Fernández Padrón

    2012-02-01

    Full Text Available Este trabajo está dirigido al rediseño del Sistema de Adquisición y Procesamiento de Datos de la Estación para el Diagnóstico de Estado en Tiempo Real del Autotransformador de Potencia No. 2 de 100MVA, de la Subestación Barquisimeto de Venezuela, a partir de controladores embebidos en tiempo real de la familia cRIO de National Instruments y las técnicas de programación que ofrece la plataforma NI LabVIEW, con la finalidad de integrar un sistema único (software-hardware que permita aumentar la calidad en las mediciones, el procesamiento de los datos, la interface hombre-máquina, su capacidad de expansión y reproducibilidad. El mismo puede ser accedido mediante navegadores Web de Internet y transferir datos en tiempo real a través de la red, además es capaz de trabajar autónomo presentando respaldo en comunicación y alimentación de energía eléctrica, logrando un mejor servicio de diagnóstico continuo en dicho autotransformador.This work is focused on the redesign of the Acquisition System and Processing Data of the Station for the Diagnostic that Assess the Condition in Real Time of the 100MVA Power Autotransformer No. 2 of the Substation Barquisimeto from Venezuela with the embedded controllers in real time of the cRIO technology of the National Instruments and the programming techniques supported by the NI LabVIEW platform with the purpose of integrating an unique system (hardware-software that allows to improve the quality in the measurements, the processing data, the man-machine interface, its expansion capability and reproduction. This system can be obtained by the internet web browser and it can transfer data in real time through the network, it is also able to work autonomous having a back in communicating and electrical energy feeding, getting a better continuous diagnostic service and the autotransformer.

  13. LabVIEW aplicado al diagnóstico de estado en tiempo real de transformadores de potencia; LabVIEW apply to diagnostic that assess the condition in real time of the power transfor

    Directory of Open Access Journals (Sweden)

    Eliezer Fernández Padrón

    2014-04-01

    Full Text Available Este trabajo está dirigido al rediseño del Sistema de Adquisición y Procesamiento de Datos de la Estación para el Diagnóstico de Estado en Tiempo Real del Autotransformador de Potencia No. 2 de 100MVA, de la Subestación Barquisimeto de Venezuela, a partir de controladores embebidos en tiempo real de la familia cRIO de National Instruments y las técnicas de programación que ofrece la plataforma NI LabVIEW, con la finalidad de integrar un sistema único (software-hardware que permita aumentar la calidad en las mediciones, el procesamiento de los datos, la interface hombre-máquina, su capacidad de expansión y reproducibilidad. El mismo puede ser accedido mediante navegadores Web de Internet y transferir datos en tiempo real a través de la red, además es capaz de trabajar autónomo presentando respaldo en comunicación y alimentación de energía eléctrica, logrando un mejor servicio de diagnóstico continuo en dicho autotransformador.  This work is focused on the redesign of the Acquisition System and Processing Data of the Station for the Diagnostic that Assess the Condition in Real Time of the 100MVA Power Autotransformer No. 2 of the Substation Barquisimeto from Venezuela with the embedded controllers in real time of the cRIO technology of the National Instruments and the programming techniques supported by the NI LabVIEW platform with the purpose of integrating an unique system (hardware-software that allows to improve the quality in the measurements, the processing data, the man-machine interface, its expansion capability and reproduction. This system can be obtained by the internet web browser and it can transfer data in real time through the network, it is also able to work autonomous having a back in communicating and electrical energy feeding, getting a better continuous diagnostic service and the autotransformer.

  14. Controlled peroxide-induced degradation of polypropylene in a twin-screw extruder: change of molecular weight distribution under conditions controlled by micromixing

    NARCIS (Netherlands)

    Iedema, P.D.; Remerie, K.; van der Ham, M.; Biemond, E.; Tacx, J.

    2011-01-01

    Controlled degradation of polypropylene (PP) by peroxide was carried out in a laboratory twin-screw extruder ZSK 18 and the change in Molecular Weight Distribution (MWD) was measured using Size Exclusion Chromatography-Differential Viscosimetry (SEC-DV). The MWD results were compared to MWD predicti

  15. Solid lipid particles for oral delivery of peptide and protein drugs III - the effect of fed state conditions on the in vitro release and degradation of desmopressin

    DEFF Research Database (Denmark)

    Christophersen, Philip C; Vaghela, Dimple; Müllertz, Anette;

    2014-01-01

    of oleic acid glycerides accelerated the release of desmopressin significantly from all solid lipid particles both in the presence and absence of lipase. The presence of oleic acid glycerides also reduced the degradation rate of desmopressin, probably due to the interactions between the lipids...

  16. Self-induced bio-potential and graphite electron accepting conditions enhances petroleum sludge degradation in bio-electrochemical system with simultaneous power generation.

    Science.gov (United States)

    Mohan, S Venkata; Chandrasekhar, K

    2011-10-01

    Bio-electrochemical treatment (BET) documented effective degradation of real field petroleum sludge over the conventional anaerobic treatment (AnT). BET (41.08%) operation showed enhanced total petroleum hydrocarbons (TPH) removal over AnT (20.72%). Aromatic fraction visualized higher removal (75.54%) compared to other TPH fractions viz., aliphatics, asphaltenes and NSO (nitrogen, sulfur and oxygen) during BET operation. Higher ring aromatics (5-6) documented easy degradation in BET, while AnT was limited to lower ring (2-3) compounds. Voltammetric analysis evidenced simultaneous redox behavior during BET operation due to presence of graphite electrode as electron acceptor, while AnT showed extended reduction behavior only. Self-induced primary and secondary oxidation reactions and capacitive-deionization might have enhanced the degradation capability of BET. BET documented higher charge/capacitance (2810 mJ/1120 mF) than AnT (450 mJ/180 mF). Power output corroborated well with observed results supporting BET performance as fuel cell. Electrodes offer a potential alternative electron acceptor for promoting the degradation of organic contaminants.

  17. Survey of ectomycorrhizal, litter-degrading, and wood-degrading Basidiomycetes for dye decolorization and ligninolytic enzyme activity.

    Science.gov (United States)

    Casieri, Leonardo; Anastasi, Antonella; Prigione, Valeria; Varese, Giovanna Cristina

    2010-11-01

    Basidiomycetes are essential in forest ecology, being deeply involved in wood and litter decomposition, humification, and mineralization of soil organic matter. The fungal oxidoreductases involved in these processes are today the focus of much attention with a view to their applications. The ecological role and potential biotechnological applications of 300 isolates of Basidiomycetes were assessed, taking into account the degradation of model dyes in different culture conditions and the production of oxidoreductase enzymes. The tested isolates belong to different ecophysiological groups (wood-degrading, litter-degrading, ectomycorrhizal, and coprophilous fungi) and represent a broad systematic and functional biodiversity among Basidiomycetes occurring in deciduous and evergreen forests of northwest Italy (Piedmont Region). The high number of species tested and the use of different culture conditions allowed the investigation of the degradation activity of several novel species, neglected to date. Oxidative enzyme activities varied widely among all ecophysiological groups and laccases were the most commonly detected enzymes. A large number of isolates (86%), belonging to all ecophysiological groups, were found to be active against at least one model dye; the wood-degrading fungi represented the most efficient group. Noteworthily, also some isolates of litter-degrading and ectomycorrhizal fungi achieved good decolorization yield. The 25 best isolates were then tested against nine industrial dyes commonly employed in textile industries. Three isolates of Bjerkandera adusta efficiently decolorized the dyes on all media and can be considered important candidates for application in textile wastewater treatment.

  18. Validated specific HPLC methods for determination of prazosin, terazosin and doxazosin in the presence of degradation products formed under ICH-recommended stress conditions.

    Science.gov (United States)

    Bakshi, Monika; Ojha, Tina; Singh, Saranjit

    2004-01-27

    The present paper describes development of stability-indicating high-performance liquid chromatographic (HPLC) assay methods for three alpha-adrenergic-blocker drug substances, namely, prazosin, terazosin and doxazosin, in the presence of degradation products generated from forced decomposition studies. Resolution of drugs from degradation products was obtained using a reversed-phase C-18 column using water/acetonitrile/methanol/glacial acetic acid/diethylamine (25:35:40:1:0.017) as mobile phase for prazosin and terazosin and acetonitrile/water/glacial acetic acid/diethylamine (65:35:1:0.02) for doxazosin. The detection was done at 254 nm. The methods were validated with respect to linearity, precision, accuracy, specificity and robustness.

  19. Effect of a Convective Boundary Condition on Boundary Layer Slip Flow and Heat Transfer Over a Stretching Sheet in View of the Exact Solution

    Science.gov (United States)

    Aljoufi, Mona D.; Ebaid, Abdelhalim

    2016-12-01

    The exact solutions of a nonlinear differential equations system, describing the boundary layer flow over a stretching sheet with a convective boundary condition and a slip effect have been obtained in this paper. This problem has been numerically solved by using the shooting method in literature. The aim of the current paper is to check the accuracy of these published numerical results. This goal has been achieved via first obtaining the exact solutions of the governing nonlinear differential equations and then, by comparing them with the approximate numerical results reported in literature. The effects of the physical parameters on the flow field and the temperature distribution have been re-investigated through the new exact solutions. The main advantage of the current paper is the simple computational approach that has been introduced to analyze exactly the present physical problem. This simple analytical approach can be further applied to investigate similar problems. Although no remarkable differences have been detected between the current figures and those obtained in literature, the authors believe that if some numerical calculations were available for the fluid velocity and the temperature in literature then the convergence criteria and the accuracy of the shooting method used in Ref. [15] can be validated in view of the current exact expressions.

  20. Optimization of Lactose degradation conditions by mixed fermentation from Kluyveromyces Lactis and lactobacillus%乳酸克鲁维酵母与乳酸菌混菌发酵对乳糖降解条件的优化

    Institute of Scientific and Technical Information of China (English)

    梁龙; 牟光庆; 陈历俊; 姜铁民

    2013-01-01

    In order to optimize the lactose degradation conditions by mixed fermentation from Kluyveromyces Lactis and Lactobacillus bulgaricus and Streptococcus thermophilus,Three factors influenced the lactose degradation rate were studied,including inoculum density of Kluyveromyces Lactis,fermentation temperature,fermentation time,and orthogonal test was used to optimize the parameters.Direct colorimetric method was used for the determination of lactose content.The result showed that the optimum conditions of lactose degradation by mixed fermentation were inoculum density ofKluyveromyces Lactis 5log cfu·mL-1,fermentation temperature 30 ℃,fermentation time 6.5 h.Under the above conditions,the average lactose degradation rate was 25.45%.%为优化乳酸克鲁维酵母与德氏乳杆菌保加利亚亚种及嗜热链球菌混菌发酵降解乳糖的条件,研究了乳酸克鲁维酵母的接种量、发酵温度和发酵时间3个因素对乳糖降解率的影响,并采用正交试验优化参数.利用直接比色法测定乳糖质量浓度.结果表明,最佳混菌发酵降解乳糖的条件为乳酸克鲁维酵母的接种量5.5 mL-1(对数值),发酵温度32℃,发酵时间5.5 h.此条件平均乳糖降解率为25.45%.

  1. 纤维素降解菌株的筛选及其产酶条件优化%Studies on Screening of Methane Fermentation Cellulose degrading Bacteria and its Optimization of Culture Conditions

    Institute of Scientific and Technical Information of China (English)

    高星爱; 黄枭; 张永锋; 赵新颖; 程孟秋; 刘鹏; 刘思言

    2012-01-01

    为了寻求快速有效降解沼气发酵有机质中的高分子化合物,本实验从腐殖质土壤中筛选到一株高效降解纤维素菌株,在以羧甲基纤维素钠为唯一碳源的液体培养基中培养,所产生的纤维素酶对玉米芯和滤纸均表现出较强降解能力.其次做了对菌株培养条件优化的实验,结果表明,菌株的最佳降解纤维素条件为反应温度30℃、发酵液接种量为1%、0.75%羧甲基纤维素钠为碳源、1.5%胰蛋白胨为氮源,优化菌株培养条件后,纤维素酶活力增加了2.8倍.%In order to be effective, rapid degradation of organic polymer compound biogas fermentation, from soil degradation to a plant screening high efficiency degradation cellulose strain. In sodium carboxyl methyl cellulose as the only carbon source of liquid medium training strains, the cellulose enzyme produced for several and filter paper are show have better degradation ability. Next to the optimization of the strains of the culture condition experiment results show that the best cellulolytic strains of the conditions for the reaction temperature 30°C, fermented liquid 1% inoculated quantity, carbon source sodium carboxyl methyl cellulose 0.75%, had 1.5% nitrogen pancreatic specially designed, and so on. Optimization strains after the culture condition, cellulose enzyme activity has increased 2.8times.

  2. C3降解长链烷烃的条件优化及其机理研究%Conditions Optimization and Mechanism Study of Long -Chain Alkane Degradation by C3

    Institute of Scientific and Technical Information of China (English)

    吕立君; 王光华; 李文兵; 卢露露; 刘念汝; 陈彪; 刘贝

    2016-01-01

    以正十六烷无机盐培养基为选择培养基,从武汉石化输油管附近土壤中筛选出了1株高效降解长链烷烃的菌株C3。采用摇瓶实验,研究了菌株C3降解正十六烷的降解条件、降解动力学及降解机理。菌株C3降解正十六烷的最适宜条件为温度35℃、初始pH=7、摇床转速150 r/min。动力学研究显示,在底物质量浓度为1000 mg/L时,其降解动力学拟合结果符合Monod方程,半饱和常数 Ks=609.8 mg/L ,最大降解速率vmax=62.1mg/(L・h)。对C3降解正十六烷产物进行红外光谱及GC/MS分析,推测该降解方式为末端氧化。%Regarding the mineral salt medium with the n-hexadecane as the selecting medium ,strain C3 that can effec-tively degrade the long -chain alkane is screened out from the soil near the pipeline of Wuhan Petrochemical Company .The conditions of degrading n-hexadecane ,growth kinetics and mechanism of degradation are studied by shaking flask tests .It is found that the optimum conditions for the growth of strain C 3 are under 35℃ ,pH=7 and 150 r/min of table speed .The growth kinetics research shows that when the concentration of n-hexadecane is 1 000 mg/L under optimum conditions ,the n-hexadecane degradation is in accordance with Monod equation ,with Ks being 609 .8 mg/L and vmax being 62 .1 mg/(L・h) . The products from the degradation are analyzed by infrared spectrometer and GC/MS and it is forecast that the degradation is terminal oxidation .

  3. DDE remediation and degradation.

    Science.gov (United States)

    Thomas, John E; Ou, Li-Tse; All-Agely, Abid

    2008-01-01

    DDT and its metabolites, DDD and DDE, have been shown to be recalcitrant to degradation. The parent compound, DDT, was used extensively worldwide starting in 1939 and was banned in the United States in 1973. The daughter compound, DDE, may result from aerobic degradation, abiotic dehydrochlorination, or photochemical decomposition. DDE has also occurred as a contaminant in commercial-grade DDT. The p,p'-DDE isomer is more biologically active than the o,p-DDE, with a reported half-life of -5.7 years. However, when DDT was repeatedly applied to the soil, the DDE concentration may remain unchanged for more than 20 yr. Remediation of DDE-contaminated soil and water may be done by several techniques. Phytoremediation involves translocating DDT, DDD, and DDE from the soil into the plant, although some aquatic species (duckweed > elodea > parrot feather) can transform DDT into predominantly DDD with some DDE being formed. Of all the plants that can uptake DDE, Cucurbita pepo has been the most extensively studied, with translocation values approaching "hyperaccumulation" levels. Soil moisture, temperature, and plant density have all been documented as important factors in the uptake of DDE by Cucurbita pepo. Uptake may also be influenced positively by amendments such as biosurfactants, mycorrhizal inoculants, and low molecular weight organic acids (e.g., citric and oxalic acids). DDE microbial degradation by dehalogenases, dioxygenases, and hydrolases occurs under the proper conditions. Although several aerobic degradation pathways have been proposed, none has been fully verified. Very few aerobic pure cultures are capable of fully degrading DDE to CO2. Cometabolism of DDE by Pseudomonas sp., Alicaligens sp., and Terrabacter sp. grown on biphenyl has been reported; however, not all bacterial species that produce biphenyl dioxygenase degraded DDE. Arsenic and copper inhibit DDE degradation by aerobic microorganisms. Similarly, metal chelates such as EDTA inhibit the

  4. Monitoring automotive oil degradation: analytical tools and onboard sensing technologies.

    Science.gov (United States)

    Mujahid, Adnan; Dickert, Franz L

    2012-09-01

    Engine oil experiences a number of thermal and oxidative phases that yield acidic products in the matrix consequently leading to degradation of the base oil. Generally, oil oxidation is a complex process and difficult to elucidate; however, the degradation pathways can be defined for almost every type of oil because they mainly depend on the mechanical status and operating conditions. The exact time of oil change is nonetheless difficult to predict, but it is of great interest from an economic and ecological point of view. In order to make a quick and accurate decision about oil changes, onboard assessment of oil quality is highly desirable. For this purpose, a variety of physical and chemical sensors have been proposed along with spectroscopic strategies. We present a critical review of all these approaches and of recent developments to analyze the exact lifetime of automotive engine oil. Apart from their potential for degradation monitoring, their limitations and future perspectives have also been investigated.

  5. Fe{sup 3+}-doped zeolites. Optimised conditions for the oxidative degradation of 2,4-xylidine in laboratory and solar photochemical reactors

    Energy Technology Data Exchange (ETDEWEB)

    Shahin, N.; Thanh, H. le; Bonfill, A.; Woerner, M.; Lang, J.; Bossmann, S.H.; Oliveros, E.; Braun, A.M. [Lehrstuhl fuer Umweltmesstechnik am Engler-Bunte Inst. der Univ. Karlsruhe (Germany)

    2003-07-01

    Among advanced oxidation processes (AOP), the photochemically enhanced Fenton reaction (photo-Fenton) may be considered as one of the most efficient for the degradation of contaminants in industrial wastewater. This process involves a series of complex reactions, which cannot be described completely by conventional models. Therefore, the experimental design methodology has been employed for modelling the experimental data obtained in a laboratory batch reactor as well as in a novel type of solar reactor. As heterogeneous Fenton catalyst, a Fe{sup 3+}-exchanged zeolite Y photocatalyst was employed. As a model pollutant, 2,4-dimethyl aniline (2,4-xylidine) was chosen, because its oxidative degradation chemistry is well known. The experimental design model has been used for describing the behaviour of the reaction system in sensitivity studies aimed at optimising the amounts of Fenton reagents (heterogeneous Fenton catalyst and hydrogen peroxide) employed in the process. The results show that this heterogeneous photo-Fenton process is very sensitive to the concentration of catalyst as well as of added hydrogen peroxide. (orig.)

  6. Experimental studies on urea degradation in seawater

    Digital Repository Service at National Institute of Oceanography (India)

    Rajendran, A.; Joseph, T.; Reddy, C.V.G.

    The rate of urea degradation in seawater was studied under various conditions and the kinetics of urea degradation was evaluated. Urea decomposition experiments showed that the rates and quantity of ammonium oxidation were slower in the relatively...

  7. Formation of chlorinated by-products during photo-Fenton degradation of pyrimethanil under saline conditions. Influence on toxicity and biodegradability.

    Science.gov (United States)

    Sirtori, Carla; Zapata, Ana; Malato, Sixto; Agüera, Ana

    2012-05-30

    This study evaluated the formation of chlorinated transformation products during photo-Fenton treatment of pyrimethanil (PYR-20 mg L(-1)) in two water matrices, demineralised water (DW) and water containing 5 g L(-1) of NaCl (DW(NaCl)). All experiments were carried out in compound parabolic collectors (CPC) at an initial Fe(2+) concentration of 5 mg L(-1) and H(2)O(2) concentration of 150-350 mg L(-1). Dissolved Organic Carbon (DOC), High-Performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD), Liquid Chromatography-Time-Of-Flight Mass Spectrometry (LC-TOF-MS), toxicity and biodegradability tests were conducted to control the photocatalytic treatment. In DW, PYR was completely eliminated after 11.8 min of illumination and initial DOC was reduced 50% after 79 min of illumination with 33 mM of H(2)O(2) consumed. On the other hand, in DW(NaCl) water matrix, the same reduction in DOC took 110 min of illumination and H(2)O(2) consumption of 39 mM, and total degradation of PYR was observed at 12 min of illumination. PYR transformation products (TPs) were identified by LC-TOF-MS. It was demonstrated that photo-Fenton in a DW(NaCl) produces some chlorinated TPs in addition to the non-chlorinated TPs identified during degradation in the DW. All TPs formed were eliminated during photo-Fenton. Additionally, the presence of chlorinated TPs does not increase the toxicity of the water, and TPs formed are more biodegradable than PYR.

  8. Mn(2+)-mediated homogeneous Fenton-like reaction of Fe(III)-NTA complex for efficient degradation of organic contaminants under neutral conditions.

    Science.gov (United States)

    Li, Yifan; Sun, Jianhui; Sun, Sheng-Peng

    2016-08-05

    In this work, we report a novel Mn(2+)-mediated Fenton-like process based on Fe(III)-NTA complex that is super-efficient at circumneutral pH range. Kinetics experiments showed that the presence of Mn(2+) significantly enhanced the effectiveness of Fe(III)-NTA complex catalyzed Fenton-like reaction. The degradation rate constant of crotamiton (CRMT), a model compound, by the Fe(III)- NTA_Mn(2+) Fenton-like process was at least 1.6 orders of magnitude larger than that in the absence of Mn(2+). Other metal ions such as Ca(2+), Mg(2+), Co(2+) and Cu(2+) had no impacts or little inhibitory effect on the Fe(III)-NTA complex catalyzed Fenton-like reaction. The generation of hydroxyl radical (HO) and superoxide radical anion (O2(-)) in the Fe(III)-NTA_Mn(2+) Fenton-like process were suggested by radicals scavenging experiments. The degradation efficiency of CRMT was inhibited significantly (approximately 92%) by the addition of HO scavenger 2-propanol, while the addition of O2(-) scavenger chloroform resulted in 68% inhibition. Moreover, the results showed that other chelating agents such as EDTA- and s,s-EDDS-Fe(III) catalyzed Fenton-like reactions were also enhanced significantly by the presence of Mn(2+). The mechanism involves an enhanced generation of O2(-) from the reactions of Mn(2+)-chelates with H2O2, indirectly promoting the generation of HO by accelerating the reduction rate of Fe(III)-chelates to Fe(II)- chelates. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. 氧化铋光催化剂降解亚甲基兰反应条件研究%Study on Degradation Reaction Conditions of Methylene Blue by Bismuth Oxide

    Institute of Scientific and Technical Information of China (English)

    高红; 王学同

    2014-01-01

    氧化铋作为一种光催化剂,可应用于水中有机污染物的降解,并且氧化铋可实现对太阳光的有效利用,节约水处理成本。在氧化铋降解亚甲基兰模拟废水的实验中,影响其反应效果的因素包括催化剂用量、模拟废水浓度、pH值等。通过单因素和正交实验,确定了氧化铋降解亚甲基兰反应过程中的最佳实验条件。%As a photocatalyst, bismuth oxide could be applied to degrade organic pollutants in water, achieved the effective utilization of solar energy, and saved the cost of water treatment. In the degradation of methylene blue wastewater by bismuth oxide, influence factors included catalyst dosage, wastewater concentration and pH. Through single factor and orthogonal experiments, the optimal experimental conditions of degradation of methylene blue by bismuth oxide were obtained.

  10. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    Directory of Open Access Journals (Sweden)

    Zulfa Al Disi

    2017-01-01

    Full Text Available Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16 to longer chain n-alkanes (n-C21–n-C25 and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time.

  11. Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

    Science.gov (United States)

    Al Disi, Zulfa; Jaoua, Samir; Al-Thani, Dhabia; Al-Meer, Saeed

    2017-01-01

    Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16) to longer chain n-alkanes (n-C21–n-C25) and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time. PMID:28243605

  12. Thunderstorm activity in early Earth: same estimations from point of view a role of electric discharges in formation of prebiotic conditions

    Science.gov (United States)

    Serozhkin, Yu.

    2008-09-01

    Introduction The structure and the physical parameters of an early Earth atmosphere [1], most likely, played a determining role in formation of conditions for origin of life. The estimation of thunderstorm activity in atmosphere of the early Earth is important for understanding of the real role of electrical discharges during formation of biochemical compounds. The terrestrial lightning a long time are considered as one of components determining a physical state and chemical structure of an atmosphere. Liebig in 1827 has considered a capability of nitrogen fixation at discharges of lightning [2]. Recent investigations (Lamarque et al. 1996) have achieved that production rate of NOx due to lightning at 3·106 ton/year [3]. The efficiency of electric discharges as energy source for synthesis of low molecular weight organic compounds is explained by the several factors. To them concern effect of optical radiation, high temperature, shock waves and that is especially important, pulse character of these effects. The impulse impact is essentially reduced the probability of destruction of the formed compounds. However, for some reasons is not clear the real role of electric discharges in synthesis of biochemical compounds. The discharges used in experiments on synthesis of organic substances, do not remind the discharges observable in a nature. One more aspect of a problem about a role of electric discharges in forming pre-biotic conditions on the Earth is connected with the thunderstorm activity in a modern atmosphere. This activity is connected with the presence in an atmosphere of ice crystals and existing gradient of temperature. To tell something about a degree of thunderstorm activity during the early Earth, i.e. that period, when formed pre-biotic conditions were is very difficult. Astrobiological potential of various discharges First of all the diversity of electric discharges in terrestrial atmosphere (usual lightning, lightning at eruption of volcanoes

  13. Development of bearing lubrication condition monitoring system based on LabVIEW%基于LabVIEW的轴承润滑状态监测系统开发

    Institute of Scientific and Technical Information of China (English)

    彭娅楠; 刘丽冉

    2016-01-01

    Bearing plays an important support role in rotating machinery, but the poor working environment makes the bearing become one of the most easily damaged parts. Whether the rotating machinery can be safe and stable is decided by the bearing running. At the same time, the bearings which are in the car also play an extremely important role in the drive train and running gear , it is very important for working status real-time monitoring to ensure stable operation of the vehicle and to protect the safety of the driver. In this paper, LabVIEW virtual instrument technology has developed a bearing lubrication condition monitoring system, according to the bearing status information collected by sensors in real time to accurately diagnose the bearing lubrication is a important safeguard to improve vehicle operation safety and economy.%轴承是旋转机械中一个重要的支撑部件,其恶劣的工作环境使得轴承成为最容易损坏的部件之一。旋转机械是否能够安全稳定的运行起决定性作用的就是轴承的运行状态。同时由于轴承在汽车的传动系、行驶系中也具有极其重要的作用,对轴承工作状态进行实时监测以保证车辆的稳定运行、保障驾驶员的安全性是非常重要的。文章利用虚拟仪器LabVIEW技术开发了一个轴承润滑状态监测系统,根据传感器采集的轴承状态信息,实时准确地诊断轴承润滑状态,是提高汽车运行安全性和经济性的重要保障措施。

  14. Effect of operational conditions on the degradation of organic matter and development of microalgae-bacteria consortia when treating swine slurry.

    Science.gov (United States)

    González-Fernández, Cristina; Riaño-Irazábal, Berta; Molinuevo-Salces, Beatriz; Blanco, Saúl; García-González, Maria Cruz

    2011-05-01

    There is great controversy regarding the best substrate (fresh or anaerobically digested swine slurry) for the development of microalgae-bacteria consortia. This study aims to elucidate the best substrate by assessing biomass productivity, microorganism predominance, and their ability for organic matter removal. In addition to the different substrates, different operational conditions and influent strengths were evaluated. Increasing organic matter content when favourable temperature and illumination conditions were present improved biomass production. However, these conditions were not favourable for microalgal growth, but they were favourable for bacteria. Regardless of the operational conditions, reactors fed with fresh slurry not only resulted in the highest biomass productivity, but also the greatest removal of total and soluble chemical oxygen demand (COD). On the other hand, reactors fed with digested slurry showed biomass productivity and COD removal values lower than those obtained for reactors fed with fresh slurry, most probably due to the recalcitrant nature of the former. Nevertheless, digested slurry was the substrate more appropriate for microalgae growth under harsh operational conditions (16 °C and 9-h illumination) at low influent strength and optimum operational conditions (30 °C and 24-h illumination) at higher influent strength.

  15. Autochthonous arbuscular mycorrhizal fungi and Bacillus thuringiensis from a degraded Mediterranean area can be used to improve physiological traits and performance of a plant of agronomic interest under drought conditions.

    Science.gov (United States)

    Armada, Elisabeth; Azcón, Rosario; López-Castillo, Olga M; Calvo-Polanco, Mónica; Ruiz-Lozano, Juan Manuel

    2015-05-01

    Studies have shown that some microorganisms autochthonous from stressful environments are beneficial when used with autochthonous plants, but these microorganisms rarely have been tested with allochthonous plants of agronomic interest. This study investigates the effectiveness of drought-adapted autochthonous microorganisms [Bacillus thuringiensis (Bt) and a consortium of arbuscular mycorrhizal (AM) fungi] from a degraded Mediterranean area to improve plant growth and physiology in Zea mays under drought stress. Maize plants were inoculated or not with B. thuringiensis, a consortium of AM fungi or a combination of both microorganisms. Plants were cultivated under well-watered conditions or subjected to drought stress. Several physiological parameters were measured, including among others, plant growth, photosynthetic efficiency, nutrients content, oxidative damage to lipids, accumulation of proline and antioxidant compounds, root hydraulic conductivity and the expression of plant aquaporin genes. Under drought conditions, the inoculation of Bt increased significantly the accumulation of nutrients. The combined inoculation of both microorganisms decreased the oxidative damage to lipids and accumulation of proline induced by drought. Several maize aquaporins able to transport water, CO2 and other compounds were regulated by the microbial inoculants. The impact of these microorganisms on plant drought tolerance was complementary, since Bt increased mainly plant nutrition and AM fungi were more active improving stress tolerance/homeostatic mechanisms, including regulation of plant aquaporins with several putative physiological functions. Thus, the use of autochthonous beneficial microorganisms from a degraded Mediterranean area is useful to protect not only native plants against drought, but also an agronomically important plant such as maize.

  16. Plant biomass degradation by fungi.

    Science.gov (United States)

    Mäkelä, Miia R; Donofrio, Nicole; de Vries, Ronald P

    2014-11-01

    Plant biomass degradation by fungi has implications for several fields of science. The enzyme systems employed by fungi for this are broadly used in various industrial sectors such as food & feed, pulp & paper, detergents, textile, wine, and more recently biofuels and biochemicals. In addition, the topic is highly relevant in the field of plant pathogenic fungi as they degrade plant biomass to either gain access to the plant or as carbon source, resulting in significant crop losses. Finally, fungi are the main degraders of plant biomass in nature and as such have an essential role in the global carbon cycle and ecology in general. In this review we provide a global view on the development of this research topic in saprobic ascomycetes and basidiomycetes and in plant pathogenic fungi and link this to the other papers of this special issue on plant biomass degradation by fungi. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Thraustochytrid fungoid protists in faecal pellets of the tunicate Pegea confoederata, their tolerance to deep-sea conditions and implication in degradation processes

    Digital Repository Service at National Institute of Oceanography (India)

    Raghukumar, S.; Raghukumar, C.

    pressures, 0.1 (1 atm) and 10 MPa (100 atm), and 2 temperature conditions, 30 and 10 degrees C. The results suggest that thraustochytrids found in such particulate organic matter may actively contribute to decomposition processes not only in the surface...

  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. Effect of synthesis conditions on the photocatalytic property of multiferroic BiFeO3 towards the degradation of phenol red

    Science.gov (United States)

    Dhanalakshmi, Radhalayam; Muneeswaran, M.; Giridharan, N. V.

    2016-05-01

    Multiferroic BiFeO3 has been synthesized through hydrothermal route under different reaction conditions. From the basic characterization such as of X-Ray diffraction analysis (XRD), the synthesized Nps were found to having rhombohedral structure with R3c space group. Photodegradation studies of toxic dye phenol red have been investigated under visible light irradiation. Vibrating sample magnetometer (VSM) analysis has been carried out to identify the magnetic properties and recycle ability photocatalysts.

  20. Nylon biodegradation by lignin-degrading fungi.

    OpenAIRE

    Deguchi, T; Kakezawa, M; Nishida, T

    1997-01-01

    The biodegradation of nylon by lignin-degrading fungi was investigated. The fungus IZU-154 significantly degraded nylon-66 membrane under ligninolytic conditions. Nuclear magnetic resonance analysis showed that four end groups, CHO, NHCHO, CH3, and CONH2, were formed in the biodegraded nylon-66 membranes, suggesting that nylon-66 was degraded oxidatively.

  1. Endocytic collagen degradation

    DEFF Research Database (Denmark)

    Madsen, Daniel H.; Jürgensen, Henrik J.; Ingvarsen, Signe;

    2012-01-01

    it crucially important to understand both the collagen synthesis and turnover mechanisms in this condition. Here we show that the endocytic collagen receptor, uPARAP/Endo180, is a major determinant in governing the balance between collagen deposition and degradation. Cirrhotic human livers displayed a marked......Fibrosis of the liver and its end-stage, cirrhosis, represent major health problems worldwide. In these fibrotic conditions, activated fibroblasts and hepatic stellate cells display a net deposition of collagen. This collagen deposition is a major factor leading to liver dysfunction, thus making...... up-regulation of uPARAP/Endo180 in activated fibroblasts and hepatic stellate cells located close to the collagen deposits. In a hepatic stellate cell line, uPARAP/Endo180 was shown to be active in, and required for, the uptake and intracellular degradation of collagen. To evaluate the functional...

  2. 自养条件下高氯酸盐降解细菌群落研究%The Study of the Structure of Perchlorate(ClO4-)-degrading Bacterial Communities Under Autotrophic Conditions

    Institute of Scientific and Technical Information of China (English)

    谢宇轩; 关翔宇; 于丽莎; 刘菲

    2014-01-01

    For the purpose of further investigating the biological degradation under an autotrophic condition and well understanding the microbial community structures in a complex environment, hydrogen was used as an electron donor to completely reduce perchlorate(ClO4-)in this study. The composition of microbial communities after degradation was analyzed via the construction of a cloning library by using the High-Throughput Sequencing method(HiSeq 2000). 71 days were needed to completely degrade 10 mg/L ClO4-. Microbial phylogenic analysis of HD(hydrogen degradation)after degradation indicated that the relative abundance of total bacteria in the HD was 84.96%whereas the relative abundance of Proteobacteria was 68.11%, whose percentage accounting for the total bacteria reached to 80.16%. The relative abundance of Dechloromonas which is representative in PRB was 2.7%in the HD. Simultaneously, the relative abundance of Azospira was 3.1%. KEGG was used to analyze the function of bacteria in HD. The relative abundance of genes which engaged in carbohydrate metabolism was 4.75%, and the genes included in energy metabolism was 3.35%, whereas the genes participated in nitrogen cycle was 0.72%, and the genes involving chloride transformation was 0.83%. It was demonstrated that degradation of ClO4-in a complicated condition was achieved by various kinds of microbes rather than a single one. Adding hydrogen as an electron donor to change microbial community played a role in the purification or selection process in the system, which allowed the complex systems to have the specific capacity to remove given contaminates.%旨在研究自养条件下以氢气作为电子供体高氯酸根离子(ClO4-)的微生物降解机制,利用HiSeq 2000对微生物群落结构及多样性进行高通量测序及分析。结果表明,添加氢气的HD(hydrogen degradation)体系将10 mg/L ClO4-降至检出限以下共经历71 d。ClO4-完全降解后HD体系中总细菌的相对丰度为84

  3. Polysaccharide Degradation

    Science.gov (United States)

    Stone, Bruce A.; Svensson, Birte; Collins, Michelle E.; Rastall, Robert A.

    An overview of current and potential enzymes used to degrade polysaccharides is presented. Such depolymerases are comprised of glycoside hydrolases, glycosyl transferases, phosphorylases and lyases, and their classification, active sites and action patterns are discussed. Additionally, the mechanisms that these enzymes use to cleave glycosidic linkages is reviewed as are inhibitors of depolymerase activity; reagents which react with amino acid residues, glycoside derivatives, transition state inhibitors and proteinaceous inhibitors. The characterization of various enzymes of microbial, animal or plant origin has led to their widespread use in the production of important oligosaccharides which can be incorporated into food stuffs. Sources of polysaccharides of particular interest in this chapter are those from plants and include inulin, dextran, xylan and pectin, as their hydrolysis products are purported to be functional foods in the context of gastrointestinal health. An alternative use of degraded polysaccharides is in the treatment of disease. The possibility exists to treat bacterial exopolysaccharide with lyases from bacteriophage to produce oligosaccharides exhibiting bioactive sequences. Although this area is currently in its infancy the knowledge is available to investigate further.

  4. Detection of pump degradation

    Energy Technology Data Exchange (ETDEWEB)

    Greene, R.H.; Casada, D.A.; Ayers, C.W. [and others

    1995-08-01

    This Phase II Nuclear Plant Aging Research study examines the methods of detecting pump degradation that are currently employed in domestic and overseas nuclear facilities. This report evaluates the criteria mandated by required pump testing at U.S. nuclear power plants and compares them to those features characteristic of state-of-the-art diagnostic programs and practices currently implemented by other major industries. Since the working condition of the pump driver is crucial to pump operability, a brief review of new applications of motor diagnostics is provided that highlights recent developments in this technology. The routine collection and analysis of spectral data is superior to all other technologies in its ability to accurately detect numerous types and causes of pump degradation. Existing ASME Code testing criteria do not require the evaluation of pump vibration spectra but instead overall vibration amplitude. The mechanical information discernible from vibration amplitude analysis is limited, and several cases of pump failure were not detected in their early stages by vibration monitoring. Since spectral analysis can provide a wealth of pertinent information concerning the mechanical condition of rotating machinery, its incorporation into ASME testing criteria could merit a relaxation in the monthly-to-quarterly testing schedules that seek to verify and assure pump operability. Pump drivers are not included in the current battery of testing. Operational problems thought to be caused by pump degradation were found to be the result of motor degradation. Recent advances in nonintrusive monitoring techniques have made motor diagnostics a viable technology for assessing motor operability. Motor current/power analysis can detect rotor bar degradation and ascertain ranges of hydraulically unstable operation for a particular pump and motor set. The concept of using motor current or power fluctuations as an indicator of pump hydraulic load stability is presented.

  5. Detection of pump degradation

    Energy Technology Data Exchange (ETDEWEB)

    Casada, D. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    There are a variety of stressors that can affect the operation of centrifugal pumps. Although these general stressors are active in essentially all centrifugal pumps, the stressor level and the extent of wear and degradation can vary greatly. Parameters that affect the extent of stressor activity are manifold. In order to assure the long-term operational readiness of a pump, it is important to both understand the nature and magnitude of the specific degradation mechanisms and to monitor the performance of the pump. The most commonly applied method of monitoring the condition of not only pumps, but rotating machinery in general, is vibration analysis. Periodic or continuous special vibration analysis is a cornerstone of most pump monitoring programs. In the nuclear industry, non-spectral vibration monitoring of safety-related pumps is performed in accordance with the ASME code. Pump head and flow rate are also monitored, per code requirements. Although vibration analysis has dominated the condition monitoring field for many years, there are other measures that have been historically used to help understand pump condition; advances in historically applied technologies and developing technologies offer improved monitoring capabilities. The capabilities of several technologies (including vibration analysis, dynamic pressure analysis, and motor power analysis) to detect the presence and magnitude of both stressors and resultant degradation are discussed.

  6. View relations

    DEFF Research Database (Denmark)

    Knudsen, Søren; Carpendale, Sheelagh

    2016-01-01

    In this paper, we explore the potential of using visual representations to support people in managing, organizing, and understanding relations between multiple visualization views. Multiple views can help people understand different facets of data and data processing, and are a crucial part of data...... analysis particularly when it is done collaboratively. Both the growing use of multiple views and the increasing display sizes have amplified the need to explore how to better help people to understand the relations between many views. To improve our understanding of how to visualize view relations, we...... invited visualization and interaction designers to critique and sketch representations of view relations. The participants provided design critiques, and sketched their own relation representations. Our findings expand the range and palette of ways of visually linking visualization views and suggest new...

  7. 1株瓦克青霉降解玉米秸秆条件的初步研究%Conditions to Degrade Corn Stalk by Penicillium waskmanii Strain

    Institute of Scientific and Technical Information of China (English)

    孙军德; 王鹤; 侯静; 郝捷

    2012-01-01

    从林间土壤中分离筛选获得产纤维素酶活力较高的菌株,经鉴定为瓦克青霉(Penicillium s askmanii ZN6).以滤纸酶活力为测定指标,开展瓦克青霉降解玉米秸秆条件研究,确定最佳温度32℃,起始pH 5.0,接种量6%(体积比),最适添加麸皮量为10%,降解时间72 h的滤纸酶活力达到6.27 IU/g.%A strain with fairly high celluloses activity was screened from the forest soil and identified it as Penicillium waskmanii ZN6. Study on the conditions of degrading corn stalk taking filter paper enzyme activity as an index was inaugurated, and confirmed that the optimum temperature was 32℃ , starting at pH 5.0, with 6% (v/v) of inocula, the most suitable addition amount of wheat bran at 10% , and degraded for 72 hours, the activity of filter paper enzyme was as high as 6.27 IU/g.

  8. An activated carbon fiber cathode for the degradation of glyphosate in aqueous solutions by the Electro-Fenton mode: Optimal operational conditions and the deposition of iron on cathode on electrode reusability.

    Science.gov (United States)

    Lan, Huachun; He, Wenjing; Wang, Aimin; Liu, Ruiping; Liu, Huijuan; Qu, Jiuhui; Huang, C P

    2016-11-15

    An activated carbon fiber (ACF) cathode was fabricated and used to treat glyphosate containing wastewater by the Electro-Fenton (EF) process. The results showed that glyphosate was rapidly and efficiently degraded and the BOD5/COD ratio was increased to >0.3 implying the feasibility of subsequent treatment of the treated wastewater by biological methods. The results of ion chromatography and HPLC measurements indicated that glyphosate was completely decomposed. Effective OH generation and rapid recycling/recovery of the Fe(2+) ions at the cathode were responsible primarily for the high performance of the ACF-EF process. Factors such as inlet oxygen gas flow rate, Fe(2+) dosage, initial glyphosate concentration, applied current intensity, and solution pH that may affect the efficiency of the ACF-EF process were further studied and the optimum operation condition was established. Results of SEM/EDX, BET and XPS analysis showed the deposition of highly dispersed fine Fe2O3 particles on the ACF surface during the EF reaction. The possibility of using the Fe2O3-ACF as iron source in the EF process was assessed. Results showed that the Fe2O3-ACF electrode was effective in degrading glyphosate in the EF process. The deposition of Fe2O3 particles on the ACF electrode had no adverse effect on the reusability of the ACF cathode.

  9. Preliminary study on degradation property of PE/CaO composite materials under composting conditions%聚乙烯/CaO复合材料在堆肥条件下的降解性能初探

    Institute of Scientific and Technical Information of China (English)

    杨文卿; 卓倩; 肖荔人; 许兢; 陈庆华

    2012-01-01

    The degradation of polyethylene(PE)/CaO composite material, a typical photo-calcium degradable plastic,during the high temperature aerobic composting process was studied in self-made sludge composting and material aging integrate reactor. The scanning electron microscope (SEM) and fourier transform infrared spectrum (FTIR) were applied to characterize the variation of the composite material during the composting process. The results showed that compare to pure PE,PE/CaO composite materials was much more compostable under the condition of controlled aerobic composting. Because the CaO particle in PE/CaO composite materials could absorb H2O and CO2 in composting environment,the corresponding product Ca(OH)2 and CaCO3 enlarged the material particle and then slipped off, and lots of holes were produced on the surface of PE/CaO composite materials. These holes not only increased the contact area between material and environment,but also provide passage for degradable bacteria to enter the inside of material,which enchanced the degradation rate of materials.%以光钙型环境友好塑料——聚乙烯(PE)/CaO复合材料作为研究对象,通过自制的污泥堆肥与材料老化综合反应器,利用扫描电镜(SEM)与傅立叶红外光谱(FTIR)分析仪对比研究了其在高温好氧堆肥条件下的降解情况.结果表明,PE/CaO复合材料在受控高温好氧堆肥条件下,具有比纯PE材料更优的可堆肥性能.PE/CaO复合材料的CaO颗粒能吸收堆肥环境中的H2O和CO2而生成相应的产物Ca(OH)2或CaCO3,发生涨大与脱落,从而使复合材料的表面产生孔洞,而这些孔洞不仅增大了材料与环境的接触面积,同时更为降解细菌进入材料内部提供了通道,大大加速了材料的降解速度.

  10. Potential Degradation of Polyaromatic Hydrocarbons Under Anaerobic Conditions of Mangrove Ecosystem%红树林厌氧环境对多环芳烃类有毒物的降解预测

    Institute of Scientific and Technical Information of China (English)

    梁佩芝; 顾继东

    2003-01-01

    红树林是连接陆地和海洋的重要生态系统,由于潮汐活动,氧化还原条件表现出明显的昼夜间的交替,这一生态体系中不但有大量的动植物种类,同时还有数量极高的不同种类的细菌,包括好氧和厌氧类型,厌养的硫酸(盐)还原菌已证实在降解多环芳烃有机物方面有其独特的生化优势,但从红树林中分离出的此类纯细菌还很少,在降解方面,已初步确定萘的厌氧降解途径异于好氧细菌,厌氧降解时的一系列代谢中间产物也有明显的专一性,羰基化反应是开始的一个重要步骤,而后的每步生化反应还有待进一步验证.从现有的结果可以看出,红树林中厌养的硫酸还原菌应在降解多环芳烃有机物中起到非常重要的作用.%Mangroves are vulnerable habitats to pollution and accumulation of polycyclic aromatic hydrocarbons (PAHs.Many studies have reported the aerobic biochemical pathways of PAH degradation by bacteria and fungi but little is knownabout the anaerobic ones. In this paper, naphthalene was used as a model compound for PAHs demonstrating the possibleanaerobic degradation pathways in mangrove environments. Oxidation of naphthalene was firstly found under anaerobleconditions in sediment columns and subsequently under strict anaerobic conditions and the processes were proved to besulfate-reducing dependent by testing with sodium molybdate, a specific inhibitor of sulfate reduction. Further detailed studiesisolated and identified several intermediates such as 2-naphthoate, 5,6,7,8-tetrahydro-2-NA and decalin-2-carboxylate duringthe transformation processes of naphthalene. In these studies, different initial steps (hydroxylation or carboxylation) wereproposed for naphthalene degradation. However, specific transformation steps for naphthalene will need further investigation toelucidate if degradation pathway of benzoate is involved.

  11. Screening of a Strain of Xylan-degrading Fungi and Optimization of Its Fermentation Conditions%一株降解木聚糖真菌的筛选及其发酵条件优化

    Institute of Scientific and Technical Information of China (English)

    张健; 汪桐; 徐争辉; 郭莹莹; 李峰

    2012-01-01

    [目的]从自然界中筛选出具有木聚糖酶活力的菌株,为今后降解农作物秸秆提供材料.[方法]以木聚糖为唯一碳源,从土壤中筛选能够降解木聚糖的菌株,并对其进行鉴定和发酵条件优化.[结果]从土壤中筛选出一株能够降解木聚糖的菌株,综合菌落、菌体形态特征和18S rRNA序列分析,初步鉴定该菌株为土曲霉(Asperergillus terreus thom.)GY-1.单因素试验研究表明,菌株GY-1最佳碳源为蔗糖,Mg2+能提高其木聚糖酶活力,最佳氮源为硝酸铵,最适温度为30℃,最适pH为6.0,该菌在培养52 h时木聚糖酶活力最高,为880.11 U/ml.L16(45)正交试验结果表明,GY-1的接种量以及培养基中蔗糖、Mg2+和硝酸铵的添加量对其木聚糖酶活力均有显著影响,GY-1菌株的最优发酵条件为:50 ml基础发酵培养基中,接种量2%,蔗糖1g,硝酸铵0.03 g,Mg2+0.004 mol.[结论]该研究首次报道了土曲霉具有木聚糖酶活力,为研究土曲霉降解木聚糖提供了一定的试验依据.%[Objective] To screen some xylan-degrading strains from nature and also provide material for degrading straw. [ Method ] The xylan was used as sole carbon source to screen some strain capable of degrading xylan cellulolytic from the soil, the strain was then identified, and its fermentation conditions were optimized. [ Result ] A xylan-degrading strain was screened out from the soil. According its colony, morphological characteristics and the 18S rRNA sequence analysis,the strain was identified to be Aspergillus terreus,GY-1. The single factor experiments showed that the best carbon source was sucrose, Mg2 + could improve xylanase activity,the best nitrogen source was ammonium nitrate,the most suitable temperature was 30℃ ,the most suitable pH was 6.0,xylanase activity of GY-1 was the highest for 880.11 U/ml in 52 h. And L16(4S) orthogonal test showed that the quantity of GY-1' s inoculation, sucrose, Mg2 + and ammonium nitrate dosage had a

  12. Viscoelastic properties of wood across the grain measured under water-saturated conditions up to 135\\degree C: evidence of thermal degradation

    CERN Document Server

    Placet, Vincent; Perré, Patrick; 10.1007/s10853-008-2546-9

    2009-01-01

    In this paper, the viscoelastic properties of wood under water-saturated conditions are investigated from 10\\degree C to 135\\degree C using the WAVET* apparatus. Experiments were performed via harmonic tests at two frequencies (0.1 Hz and 1 Hz) for several hours. Four species of wood were tested in the radial and tangential material directions: oak (Quercus sessiliflora), beech (Fagus sylvatica), spruce (Picea abies) and fir (Abies pectinata). When the treatment is applied for several hours, a reduction of the wood rigidity is significant from temperature values as low as 80-90\\degree C, and increases rapidly with the temperature level. The storage modulus of oak wood is divided by a factor two after three hours of exposure at 135\\degree C. This marked reduction in rigidity is attributed to the hydrolysis of hemicelluloses. The softening temperature of wood is also noticeably affected by hygrothermal treatment. After three short successive treatments up to 135\\degree C, the softening temperature of oak shifte...

  13. Degradation and toxicity depletion of RB19 anthraquinone dye in water by ozone-based technologies.

    Science.gov (United States)

    Lovato, María E; Fiasconaro, María L; Martín, Carlos A

    2017-02-01

    This research investigated the discoloration and mineralization of Reactive Blue 19 (RB19) anthraquinone dye by single ozonation, single UV radiation and ozonation jointed with UV radiation (O3/UV). The problem was approached from two points of view: with the objective of color removal or the mineralization of solution. In each case, the optimum operating conditions were different. Ozonation was the most effective treatment for color removal, while the combined O3/UV treatment was for mineralization. Major intermediates of the dye degradation were identified by gas chromatography/mass spectrometry and a degradation pathway was proposed. In addition, a clear decrease of the toxicity of the dye was achieved at the end of the experiments. The effect of initial dye concentration, pH, ozone dose, and UV radiation on the degradation of the dye and decrease of total organic carbon was investigated, in order to establish the optimal operating conditions to achieve discoloration, mineralization or a combination of both.

  14. Nylon separators. [thermal degradation

    Science.gov (United States)

    Lim, H. S.

    1977-01-01

    A nylon separator was placed in a flooded condition in K0H solution and heated at various high temperatures ranging from 60 C to 110 C. The weight decrease was measured and the molecular weight and decomposition product were analyzed to determine: (1) the effect of K0H concentration on the hydrolysis rate; (2) the effect of K0H concentration on nylon degradation; (3) the activation energy at different K0H concentrations; and (4) the effect of oxygen on nylon degradation. The nylon hydrolysis rate is shown to increase as K0H concentration is decreased 34%, giving a maximum rate at about 16%. Separator hydrolysis is confirmed by molecular weight decrease in age of the batteries, and the reaction of nylon with molecular oxygen is probably negligible, compared to hydrolysis. The extrapolated rate value from the high temperature experiment correlates well with experimental values at 35 degrees.

  15. Using conditionality as a solution to the problem of low uptake of essential services among disadvantaged communities: a social determinants view.

    Science.gov (United States)

    Forde, Ian; Bell, Ruth; Marmot, Michael G

    2011-08-01

    Conditional cash transfer schemes, which use cash to incentivize uptake of basic health and educational services, are well established among social planners inlow- and middle-income countries and are now taking hold in high-income countries. We appraised these schemes within a social determinants framework and found some encouraging signs in their first decade of operation. Success, however, has been inconsistent, and it is unclear whether conditional cash transfer schemes can reliably secure meaningful improvements in participants' health and nutritional status or educational attainment. Conditional cash transfer schemes' objectives will not be met unless they are transformed in 3 ways: transferring power as well as resources, emphasizing entitlements alongside conditionality, and avoiding the trap of incoherent or residualized policy.

  16. Recovering of images degraded by atmosphere

    Science.gov (United States)

    Lin, Guang; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

    2017-08-01

    Remote sensing images are seriously degraded by multiple scattering and bad weather. Through the analysis of the radiative transfer procedure in atmosphere, an image atmospheric degradation model considering the influence of atmospheric absorption multiple scattering and non-uniform distribution is proposed in this paper. Based on the proposed model, a novel recovering method is presented to eliminate atmospheric degradation. Mean-shift image segmentation and block-wise deconvolution are used to reduce time cost, retaining a good result. The recovering results indicate that the proposed method can significantly remove atmospheric degradation and effectively improve contrast compared with other removal methods. The results also illustrate that our method is suitable for various degraded remote sensing, including images with large field of view (FOV), images taken in side-glance situations, image degraded by atmospheric non-uniform distribution and images with various forms of clouds.

  17. The Prevailing Weather and Traffic Conditions in the Evaluation of a Future ECA in the Mediterranean Sea. A view into the Western Mediterranean

    Directory of Open Access Journals (Sweden)

    Marcella Castells i Sanabra

    2014-03-01

    Full Text Available Appendix III of MARPOL's Annex VI sets out the criteria and procedures for designating an emission control area (ECA.These criteria includes: a clear delineation of the proposed ECA; types of emissions proposed for control, land and sea areas at risk; emission quantification and impact assessment; prevailing weather conditions; data and quality on marine traffic; land based measures concurrent with the ECA adoption and the relative costs of reducing emissions from ships. This paper analyses the climate parameter together with traffic conditions: prevailing weather conditions as a parameter to be kept in mind for the adoption of a future ECA in the Mediterranean Sea. Preliminary results would show how marine emissions coming from existing traffic will impact the sea and land ecology in the Mediterranean area.

  18. Degradation Kinetics of Pigments from Pitaya (Hylocereus polyrhizus) under Different pH Conditions%不同pH值条件下火龙果色素的降解动力学

    Institute of Scientific and Technical Information of China (English)

    叶丽君; 邵伟琪; 王兴莉; 黄雪松

    2012-01-01

    以火龙果色素提取液的吸光度变化为指标,研究其在pH2.0~9.0条件下的降解规律。结果表明:在室温(28℃)、pH2.0~9.0时,火龙果色素的最大吸收波长分别为532、534、536、534、535、536、538、543nm。火龙果色素在特定pH值条件下的降解符合一级反应规律。降解速率常数(脚与pH值呈抛物线关系。pH4.0~6.0范围内,列皮小,色素稳定性较好。%The effect of pH 2.0-9.0 on the maximum absorption wavelength of pitaya pigment extract was analyzed. Meanwhile, we studied the degradation kinetics of the pigment extract. It was found that pitaya pigment extract showed maximum absorption at 532, 534, 536, 534, 535, 536, 538 nm and 543 nm, respectively under the conditions of 28℃ and pH 2.0-9.0. The degradation of the extract obeyed first-order reaction at specific pH levels. A parabolic relationship between rate constant (k) and pH was found. At pH levels between 4.0 and 6.0, smaller k values were obtained and the extract was stable.

  19. Sono-synthesis of solar light responsive S-N-C-tri doped TiO2 photo-catalyst under optimized conditions for degradation and mineralization of Diclofenac.

    Science.gov (United States)

    Ramandi, Sara; Entezari, Mohammad H; Ghows, Narjes

    2017-09-01

    C-N-S-tri doped TiO2 anatase phase was synthesized using a facile, effective and novel sonochemical method at low frequency (20kHz) and at room temperature. Titanium butoxide as the titanium precursor and thiourea as the dopant source were used in the synthesis of the photo-catalyst. The effects of important parameters such as thiourea/Ti molar ratio, ultrasound intensity, sonication time and temperature were studied on the synthesis of tri-doped TiO2. The XPS results confirmed the presence of N, S, and C in the photo-catalyst. The photo-catalytic efficiency of the synthesized catalyst was studied toward the removal of Diclofenac as a model pharmaceutical organic pollutant. The results confirmed that the photo-catalyst synthesized with narrower band gap energy, shorter sonication time and higher ultrasound intensity leads to a rapid removal of Diclofenac. The effect of operational variables on the photo-catalytic activity of C-N-S tri doped TiO2 nanoparticles was studied and optimized using the Taguchi method as a statistical technique. Additionally, the degradation process followed the pseudo-first-order kinetics model and the highest apparent rate constant of 0.0632min(-1) achieved in 90min. Chemical oxygen demand (COD) analysis confirmed that the mineralization took place completely (100%) under the optimized conditions in 180min. Different scavengers were applied during the degradation process and active species such as OH and O2(-) had key roles in the photo-catalytic process. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Learning View Generalization Functions

    CERN Document Server

    Breuel, Thomas M

    2007-01-01

    Learning object models from views in 3D visual object recognition is usually formulated either as a function approximation problem of a function describing the view-manifold of an object, or as that of learning a class-conditional density. This paper describes an alternative framework for learning in visual object recognition, that of learning the view-generalization function. Using the view-generalization function, an observer can perform Bayes-optimal 3D object recognition given one or more 2D training views directly, without the need for a separate model acquisition step. The paper shows that view generalization functions can be computationally practical by restating two widely-used methods, the eigenspace and linear combination of views approaches, in a view generalization framework. The paper relates the approach to recent methods for object recognition based on non-uniform blurring. The paper presents results both on simulated 3D ``paperclip'' objects and real-world images from the COIL-100 database sho...

  1. Photocatalytic degradation investigation of dicofol

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Photocatalytic degradation of dicofol was investigated on TiO2 nano particles(TiO2-NPs)under UV light irradiation.It was shown that dicofol could be completely degraded into inorganic chloride ion under the condition of 0.25 mg/mL TiO2-NPs,2 h irradiation of 400 W high pressure mercury lamp with a wavelength of 365 nm and air at a rate of 100 mL/min.The effects of the experimental conditions,including the amount of TiO2-NPs,irradiation time and the intensity of light,were studied.The apparent photodegradation rate constant was 0.167/min under the optimal condition.The photocatalytic degradation mechanism of dicofol was also discussed.

  2. Microbial Enzymatic Degradation of Biodegradable Plastics.

    Science.gov (United States)

    Roohi; Bano, Kulsoom; Kuddus, Mohammed; Zaheer, Mohammed R; Zia, Qamar; Khan, Mohammed F; Ashraf, Ghulam Md; Gupta, Anamika; Aliev, Gjumrakch

    2017-01-01

    The renewable feedstock derived biodegradable plastics are important in various industries such as packaging, agricultural, paper coating, garbage bags and biomedical implants. The increasing water and waste pollution due to the available decomposition methods of plastic degradation have led to the emergence of biodegradable plastics and biological degradation with microbial (bacteria and fungi) extracellular enzymes. The microbes utilize biodegradable polymers as the substrate under starvation and in unavailability of microbial nutrients. Microbial enzymatic degradation is suitable from bioremediation point of view as no waste accumulation occurs. It is important to understand the microbial interaction and mechanism involved in the enzymatic degradation of biodegradable plastics under the influence of several environmental factors such as applied pH, thermo-stability, substrate molecular weight and/or complexity. To study the surface erosion of polymer film is another approach for hydrolytic degradation characteristion. The degradation of biopolymer is associated with the production of low molecular weight monomer and generation of carbon dioxide, methane and water molecule. This review reported the degradation study of various existing biodegradable plastics along with the potent degrading microbes (bacteria and fungi). Patents available on plastic biodegradation with biotechnological significance is also summarized in this paper. This paper assesses that new disposal technique should be adopted for the degradation of polymers and further research is required for the economical production of biodegradable plastics along with their enzymatic degradation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Pathophysiology of juvenile idiopathic arthritis induced pes planovalgus in static and walking condition: a functional view using 3D gait analysis.

    Science.gov (United States)

    Merker, Josephine; Hartmann, Matthias; Kreuzpointner, Florian; Schwirtz, Ansgar; Haas, Johannes-Peter

    2015-06-10

    Patients suffering from juvenile idiopathic arthritis (JIA) frequently have affected ankle joints, which can lead to foot deformities such as pes planovalgus (JIA-PPV). Usually, JIA-PPV is diagnosed by examining the foot in non-weightbearing or in weightbearing, static condition. However, functional limitations typically appear during dynamic use in daily activities such as walking. The aim of this study was to quantify the pathophysiology of JIA-PPV in both static and dynamic condition, i.e. in upright standing and during the stance phase of walking using three-dimensional (3d) gait analysis. Eleven JIA patients (age = 12y) with at least one affected ankle joint and fixed pes planovalgus (≥5°) were compared to healthy controls (CG) (n = 14, age = 11y). Kinematic and kinetic data were obtained in barefoot standing and walking condition (1.1-1.3 m/s) with an 8-camera 3d motion analysis system including two force-plates and one pressure distribution plate. All participants were prepared using reflecting markers according to the Oxford Foot and Plug-in-Gait Model. Results were compared using the Mann-Whitney-U-test and Wilcoxon signed-rank test (p walking condition. JIA-PPV showed a greater hindfoot/tibia eversion during walking (midstance) compared to standing (p = 0.021) in contrast to CG. The arch index, measured by plantar pressure distribution, indicates a reduced arch height in JIA-PPV (p = 0.007). Patients had a lower maximum dorsiflexion of hindfoot/tibia (p = 0.001) and a lower plantarflexion of forefoot/hindfoot (p = 0.028), both when standing and walking. The kinetic results showed lower maximum ankle dorsiflexion moments (p walking indicated that excessive hindfoot eversion produces accessory symptoms such as a reduced arch height, increased forefoot supination and reduced propulsion effect of the ankle. Muscular and coordinative insufficiency caused by arthritis can lead to the observed increased hindfoot eversion from

  4. Photothermal degradation studies

    Science.gov (United States)

    Liang, R. H.

    1985-01-01

    Key reaction intermediates of photooxidation identified and characterized by laser flash Electron Spin Resonance (ESR) spectroscopy were discussed. Effects of temperature and ultraviolet intensity were studied in order to develop meaningful accelerated testing procedures for encapsulant evaluation. In a program to study the failure of Tedlar/ethylene vinyl acetate (EVA)/stainless steel modules, failure modes similar to those observed outdoors in real-time conditions were simulated in accelerated testing. An experimental technique was developed to quantitatively assess the extent of degradation.

  5. Ecosystemic approaches to land degradation

    Energy Technology Data Exchange (ETDEWEB)

    Puigdefabregas, J.; Barrio, G. del; Hill, J.

    2009-07-01

    Land degradation is recognized as the main outcome of desertification. However available procedures for its assessment are still unsatisfactory because are often too costly for surveying large areas and rely on specific components of the degradation process without being able to integrate them in a unique process. One of the objectives of De Survey project is designing and implementing operational procedures for desertification surveillance, including land degradation. A strategic report was compiled and reproduced here for selecting the most appropriate approaches to the project conditions. The report focuses on using attributes of ecosystem maturity as a natural way to integrate the different drivers of land degradation in simple indices. The review surveys different families of attributes concerned with water and energy fluxes through the ecosystem, its capacity to sustain biomass and net primary productivity, and its capacity to structure the space. Finally, some conclusions are presented about the choice criteria of the different approaches in the framne of operational applications. (Author) 20 refs.

  6. MARKOV CHAIN MODELING OF PERFORMANCE DEGRADATION OF PHOTOVOLTAIC SYSTEM

    Directory of Open Access Journals (Sweden)

    E. Suresh Kumar

    2012-01-01

    Full Text Available Modern probability theory studies chance processes for which theknowledge of previous outcomes influence predictions for future experiments. In principle, when a sequence of chance experiments, all of the past outcomes could influence the predictions for the next experiment. In Markov chain type of chance, the outcome of a given experiment can affect the outcome of the next experiment. The system state changes with time and the state X and time t are two random variables. Each of these variables can be either continuous or discrete. Various degradation on photovoltaic (PV systems can be viewed as different Markov states and further degradation can be treated as the outcome of the present state. The PV system is treated as a discrete state continuous time system with four possible outcomes, namely, s1 : Good condition, s2 : System with partial degradation failures and fully operational, s3 : System with major faults and partially working and hence partial output power, s4 : System completely fails. The calculation of the reliability of the photovoltaic system is complicated since the system have elements or subsystems exhibiting dependent failures and involving repair and standby operations. Markov model is a better technique that has much appeal and works well when failure hazards and repair hazards are constant. The usual practice of reliability analysis techniques include FMEA((failure mode and effect analysis, Parts count analysis, RBD ( reliability block diagram , FTA( fault tree analysis etc. These are logical, boolean and block diagram approaches and never accounts the environmental degradation on the performance of the system. This is too relevant in the case of PV systems which are operated under harsh environmental conditions. This paper is an insight into the degradation of performance of PV systems and presenting a Markov model of the system by means of the different states and transitions between these states.

  7. Optimization of protoplast fusion conditions of bacteria able to de-grade bensulfuron-methyl and butachlor%苄嘧磺隆和丁草胺降解菌原生质体融合条件优化

    Institute of Scientific and Technical Information of China (English)

    李春艳; 吴志洋; 冯丽萍; 熊明华; 成小松

    2014-01-01

    In this study, functional fusants with dual functions to simultaneously degrade bensulfuron-methyl and butachlor were constructed through protoplast fusion of Rhodococcus sp. BX2 and Acinetobacter sp.LYC-1. The protoplast fusion condition was optimized and finally the fusion frequency reached to 2.67 × 10-7 under the following condition:40%of PEG4000, 10 min, 35℃, 500μL of freshly-prepared calcium phosphate, pH 7.5. The fusant F1 was obtained with the use of penicillin G and fosfomycin as selection markers and determined to be able to pass more than eight generations stablely on the plates containing bensulfuron-methyl and butachlor. The fusant F1 had respective high degradation rate of 65.35%BSM and 62.41%butachlor in mineral medium supplemented by BSM 100 mg·L-1 and butachlor 100 mg·L-1.%研究以苄嘧磺隆降解菌Rhodococcus sp. BX2与丁草胺降解菌Acinetobacter sp. LYC-1为亲本,优化用于构建可同时降解苄嘧磺隆与丁草胺的融合子的原生质体融合条件。通过单因素试验和正交试验,确定原生质体融合的最佳条件:PEG400040%、35℃、10 min,500μL新生磷酸钙溶液,pH 7.5,此条件下融合频率达到2.67×10-7。以青霉素和磷霉素作为筛选的遗传标记,最终获得在含有上述两种除草剂的无机盐培养基中可稳定继代培养8代以上的融合子F1。该融合子在含有100 mg·mL-1苄嘧磺隆和100 mg·mL-1丁草胺的无机盐培养基中,F1的降解率分别为65.35%和62.41%。

  8. Parent versus professional views of the developmental impact of a multi-faceted condition at school age: otitis media with effusion ('glue ear').

    Science.gov (United States)

    Higson, Josephine; Haggard, Mark

    2005-12-01

    Several aspects of children's health and development are known from empirical studies to be associated with otitis media with effusion (OME; 'glue ear'). The 'diffuse image' has been an obstacle to defining a core set of impacts about which inter-profession and parent-professional communication can be effective. The study quantifies similarities and differences in how the signs, symptoms, and developmental impact of OME are attributed and construed, between teachers, parents, and ear, nose, and throat (ENT)surgeons. Convenience samples were achieved of 118 teachers and 154 parents of affected children; 178 ENT surgeons from a professional sampling frame (association membership) responded. Questionnaires elicited the perceived frequency and concern-value of over 30 manifestations of OME--the various signs, symptoms, and behaviours suggested by the literature. Factor scores derived on the combined sample were compared between respondent groups. Teachers assign high importance to education and language problems but, relative to parents, they accord lower importance to continuing hearing problems. Teachers and parents weighted behaviour and balance problems similarly, placing behaviour higher, but balance lower, than the ENT specialists did. (1) A four-factor reduction of simple questionnaire items well defines the domains of impact of OME, and can express the ways in which views of impact differ between teachers, ENT specialists and parents.(2) Considerable differences of perspective exist between the groups examined. (3) In valuing a set of measured outcomes on actual children, or for other policy research, sets of weights are now available to represent the differing perspectives of parents and professionals (e.g. in testing robustness of a conclusion across differing stakeholder perspectives). (4) The research and development need in respect of teachers' involvement with OME could profitably play to existing strengths. This implies the systematic and structured

  9. Degradation analysis of thin film photovoltaic modules

    Energy Technology Data Exchange (ETDEWEB)

    Radue, C., E-mail: chantelle.radue@nmmu.ac.z [Department of Physics, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Dyk, E.E. van [Department of Physics, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2009-12-01

    Five thin film photovoltaic modules were deployed outdoors under open circuit conditions after a thorough indoor evaluation. Two technology types were investigated: amorphous silicon (a-Si:H) and copper indium gallium diselenide (CIGS). Two 14 W a-Si:H modules, labelled Si-1 and Si-2, were investigated. Both exhibited degradation, initially due to the well-known light-induced degradation described by Staebler and Wronski [Applied Physics Letters 31 (4) (1977) 292], and thereafter due to other degradation modes such as cell degradation. The various degradation modes contributing to the degradation of the a-Si:H modules will be discussed. The initial maximum power output (P{sub MAX}) of Si-1 was 9.92 W, with the initial light-induced degradation for Si-1 approx30% and a total degradation of approx42%. For Si-2 the initial P{sub MAX} was 7.93 W, with initial light-induced degradation of approx10% and a total degradation of approx17%. Three CIGS modules were investigated: two 20 W modules labelled CIGS-1 and CIGS-2, and a 40 W module labelled CIGS-3. CIGS-2 exhibited stable performance while CIGS-1 and CIGS-3 exhibited degradation. CIGS is known to be stable over long periods of time, and thus the possible reasons for the degradation of the two modules are discussed.

  10. The coming and going of a marl lake: multi-indicator palaeolimnology reveals abrupt ecological change and alternative views of reference conditions

    Directory of Open Access Journals (Sweden)

    Emma eWiik

    2015-08-01

    Full Text Available Eutrophication is the most pressing threat to highly calcareous (marl lakes in Europe. Despite their unique chemistry and biology, comprehensive studies into their unimpacted conditions and eutrophication responses are underrepresented in conservation literature. A multi-indicator palaeolimnological study spanning ca 1260 to 2009 was undertaken at Cunswick Tarn (UK, a small, presently eutrophic marl lake, in order to capture centennial timescales of impact. Specific aims were to 1 establish temporal patterns of change (gradual/abrupt across biological groups, thereby testing theories of resistance of marl lake benthic communities to enrichment, and 2 compare the core record of reference condition with prevailing descriptions of high ecological status. Analyses of sediment calcium (Ca, phosphorus (P, pigments, diatoms, testate amoebae, cladocerans, and macrofossils, revealed three abrupt changes in ecosystem structure. The first (1900s, with biomass increases in charophytes and other benthic nutrient-poor indicators, supported ideas of resistance to eutrophication in Chara lakes. The second transition (1930s, from charophyte to angiosperm dominance, occurred alongside reductions in macrophyte cover, increases in eutrophic indicators, and a breakdown in marling, in support of ideas of threshold responses to enrichment. Core P increased consistently into the 1990s when rapid transitions into pelagic shallow lake ecology occurred and Cunswick Tarn became biologically unidentifiable as a marl lake. The moderate total P at which these changes occurred suggests high sensitivity of marl lakes to eutrophication. Further, the early record challenges ideas of correlation between ecological condition, charophyte biomass and sediment Ca. Instead, low benthic production, macrophyte cover, and Ca sedimentation, was inferred. Management measures must focus on reducing external nutrient and sediment loads at early stages of impact in order to preserve marl lakes.

  11. Study on optimal cultivating bacteria and its biological conditions of anthracene degrading degrading kinetics to anthracene%蒽降解菌T2的最佳培养条件及其对蒽的生物降解动力学研究

    Institute of Scientific and Technical Information of China (English)

    单宝来; 张秀霞; 张剑杰; 赵朝成

    2011-01-01

    A mixed bacteria T2 which used anthracene as the sole carbon source was screened from the long-term petroleum polluted soil. When the inoculation amount of T2, pH, temperature, shaking-bed's speed and the initial concentration of anthracene were 1% , 7, 30℃, 120 r/rain and 100 rag/L, respectively, the degrading rate of T2 to anthracene could reach 56.6% through 5 days' cultivation. The optimal cultivating conditions of strain T2 were obtained through studying the cultivating conditions of T2 , the result showed that when the inoculation amount of T2, pH, temperature and the initial concentration of anthracene were 5% , 6, 35℃ and 40 mg/L, respectively, the strain grew best. In addition, the degrading kinetics experiment of strain T2 to anthracene was carried out, the result showed that the residual concentration of anthracene Y(mg/L) and time t (h) was in line with the equation Y=2. 544 e( -0.00275)t.%从长期被石油污染的土壤中筛选得到一株以蒽为惟一碳源的混合菌T2,在接种量为1%,pH为7,温度为30℃,摇床转速为120r/min,蒽的初始浓度为100mg/L的条件下培养5d后,其对蒽的降解率可以达到56.6%。通过单因素实验和正交实验对菌种T2的培养条件进行研究,得到菌种T2的最佳培养条件为:接种量为5%,pH为6,温度为35℃,蒽的初始浓度为40mg/L时,最适合菌种生长。另外,菌种T2对蒽的降解动力学实验的结果表明,蒽的残留浓度Y(mg/L)与时间t(h)符合方程y=2.544e(-0.00275)t.

  12. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS.

    Energy Technology Data Exchange (ETDEWEB)

    Braverman, J.I.; Miller, C.A.; Ellingwood, B.R.; Naus, D.J.; Hofmayer, C.H.; Bezler, P.; Chang, T.Y.

    2001-03-22

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits.

  13. Kinetic study and mechanism of Niclosamide degradation

    Science.gov (United States)

    Zaazaa, Hala E.; Abdelrahman, Maha M.; Ali, Nouruddin W.; Magdy, Maimana A.; Abdelkawy, M.

    2014-11-01

    A spectrophotometric kinetic study of Niclosamide alkaline degradation as a function of drug concentration, alkaline concentration and temperature has been established utilizing double divisor-ratio spectra spectrophotometric method. The developed method allowed determination of Niclosamide in presence of its alkaline degradation products; namely; 2-chloro-4-nitro aniline (DEG I) and 5-chloro salicylic acid (DEG II) with characterization of its degradation mechanism. It was found that degradation kinetic of Niclosamide followed pseudo-first order under the established experimental conditions with a degradation rate constant (k) of 0.0829 mol/h and half life (t1/2) of 8.35 h. The overall degradation rate constant as a function of the temperature under the given conditions obeyed Arrhenius equation where the activation energy was calculated to be 3.41 kcal/mol.

  14. Operationalizing measurement of forest degradation

    DEFF Research Database (Denmark)

    Dons, Klaus; Smith-Hall, Carsten; Meilby, Henrik

    2015-01-01

    Quantification of forest degradation in monitoring and reporting as well as in historic baselines is among the most challenging tasks in national REDD+ strategies. However, a recently introduced option is to base monitoring systems on subnational conditions such as prevalent degradation activities....... In Tanzania, charcoal production is considered a major cause of forest degradation, but is challenging to quantify due to sub-canopy biomass loss, remote production sites and illegal trade. We studied two charcoal production sites in dry Miombo woodland representing open woodland conditions near human...... settlements and remote forest with nearly closed canopies. Supervised classification and adaptive thresholding were applied on a pansharpened QuickBird (QB) image to detect kiln burn marks (KBMs). Supervised classification showed reasonable detection accuracy in the remote forest site only, while adaptive...

  15. Feasibility study of superconducting power cables for DC electric railway feeding systems in view of thermal condition at short circuit accident

    Science.gov (United States)

    Kumagai, Daisuke; Ohsaki, Hiroyuki; Tomita, Masaru

    2016-12-01

    A superconducting power cable has merits of a high power transmission capacity, transmission losses reduction, a compactness, etc., therefore, we have been studying the feasibility of applying superconducting power cables to DC electric railway feeding systems. However, a superconducting power cable is required to be cooled down and kept at a very low temperature, so it is important to reveal its thermal and cooling characteristics. In this study, electric circuit analysis models of the system and thermal analysis models of superconducting cables were constructed and the system behaviors were simulated. We analyzed the heat generation by a short circuit accident and transient temperature distribution of the cable to estimate the value of temperature rise and the time required from the accident. From these results, we discussed a feasibility of superconducting cables for DC electric railway feeding systems. The results showed that the short circuit accident had little impact on the thermal condition of a superconducting cable in the installed system.

  16. Physico-chemical study of the thermal degradation of ions exchange resins of nuclear origin: research of conditions to limit the pollution transfer, application to electric cables; Etude physico-chimique de la degradation thermique des resines echangeuses d'ions d'origine nucleaire: recherche des conditions limitant le transfert de pollution, application aux cables electriques

    Energy Technology Data Exchange (ETDEWEB)

    Antonetti, P

    1999-07-01

    The ions exchange resins are one solid form of radioactive wastes. They are found mainly during the demineralization operations of the water from reactors cooling systems. This study aims to determine the conditions of a thermal processing leading to the production of a smaller residue, containing the whole activity. A protocol is proposed and validated on resins allowing a decrease of the volume of 63% for 99,93% of the activity. (A.L.B.)

  17. 降解油茶粕发酵生产芽孢杆菌培养基条件优化%Optimizing of Culture Medium Condition for Yielding Bacillus Subtilis Using Degradation Camellia Meal

    Institute of Scientific and Technical Information of China (English)

    丁丽霞; 黎继烈; 朱晓媛; 钟海雁

    2013-01-01

    Used degradation camellia meal as raw material producted Bacillus subtilis in liquid fermentation. The single factor experiment, Plackett-Burman experiment, the steepest climbing experimentally determined the response and the center value of culture medium composition. And then, through the orthogonal experiments eventually determined manufacturing bacillus subtilis culture medium condition is degradation camellia meal 13 g, soluble starch 1 g, urea 1.5 g, Na2HPO4 0.05g, MgSO4·7H2O 0.015 g, beef cream 0.2 g, FeSO4·7H2O s 0.03 g, yeast anointed 0.5 g, distilled water 100 mL, natural pH, 121 ℃ sterilization 30min, 5 mL bacteria, 37 ℃, 150r/min wave bed and the fermentation time is 24 h, we got fermented liquid with 108/mL of Bacillus subtilis.%以降解油茶粕为原料,液态发酵生产枯草芽孢杆菌.经单因素实验、Plackett-Burman实验、最陡爬坡实验确定培养基组成因素的响应值及中心点,通过正交实验优化生产枯草芽孢杆菌的培养基条件.试验结果显示:优化的培养基条件是:降解油茶粕13g,可溶性淀粉1g,尿素1.5 g,磷酸氢二钠0.05 g,七水硫酸镁0.015 g,牛肉膏0.2 g,七水硫酸亚铁0.03 g,酵母膏0.5 g,蒸馏水100 mL,自然pH.于121℃灭菌30 min后接种5mL菌悬液,37℃150 r/min摇床培养24 h,得到含108个/mL的枯草芽孢杆菌液态发酵液.

  18. Quantitative proteomic view on secreted, cell surface-associated, and cytoplasmic proteins of the methicillin-resistant human pathogen Staphylococcus aureus under iron-limited conditions.

    Science.gov (United States)

    Hempel, Kristina; Herbst, Florian-Alexander; Moche, Martin; Hecker, Michael; Becher, Dörte

    2011-04-01

    Staphylococcus aureus is capable of colonizing and infecting humans by its arsenal of surface-exposed and secreted proteins. Iron-limited conditions in mammalian body fluids serve as a major environmental signal to bacteria to express virulence determinants. Here we present a comprehensive, gel-free, and GeLC-MS/MS-based quantitative proteome profiling of S. aureus under this infection-relevant situation. (14)N(15)N metabolic labeling and three complementing approaches were combined for relative quantitative analyses of surface-associated proteins. The surface-exposed and secreted proteome profiling approaches comprise trypsin shaving, biotinylation, and precipitation of the supernatant. By analysis of the outer subproteomic and cytoplasmic protein fraction, 1210 proteins could be identified including 221 surface-associated proteins. Thus, access was enabled to 70% of the predicted cell wall-associated proteins, 80% of the predicted sortase substrates, two/thirds of lipoproteins and more than 50% of secreted and cytoplasmic proteins. For iron-deficiency, 158 surface-associated proteins were quantified. Twenty-nine proteins were found in altered amounts showing particularly surface-exposed proteins strongly induced, such as the iron-regulated surface determinant proteins IsdA, IsdB, IsdC and IsdD as well as lipid-anchored iron compound-binding proteins. The work presents a crucial subject for understanding S. aureus pathophysiology by the use of methods that allow quantitative surface proteome profiling.

  19. Cu2O/Bi2O3光催化降解罗丹明B的工艺条件研究%Process Conditions of the Degradation of Rhodamine B by Cu2O/Bi2O3 Photocatalytic

    Institute of Scientific and Technical Information of China (English)

    梁光远; 孙伟

    2013-01-01

    This paper used supported catalyst Cu2O/Bi2O3 to study the degradation of soluble dye rhodamine B, and surveyed the impact of degradation conditions on catalytic degradation process of Rhodamine B. The results show that it has better degradation effect, degradation of 5mg/L Rhodamine B solution nearly to 100% for 5 minutes, under the optimum conditions its pH is 3-5, the catalyst is 1g/L, and the amount of hydrogen peroxide is 1.0% (volume ratio).%  本文采用负载型催化剂 Cu2O/Bi2O3,研究了对可溶性染料罗丹明 B 的降解情况。考察了降解条件对罗丹明 B 催化降解过程的影响。结果表明,对罗丹明 B 有较好的降解效果,5分钟使5mg/L 的罗丹明 B 溶液降解近100%,最佳工艺条件下 pH 为3-5,催化剂为1g/L,双氧水加入量为1.0%(体积比)。

  20. Pt/C Fuel Cell Catalyst Degradation

    DEFF Research Database (Denmark)

    Zana, Alessandro

    This thesis investigates the degradation behavior of Pt/C catalysts under simulated automotive conditions. By using the “tool box” synthesis method the Pt loading has been changed from low to high Pt loadings, therefore permitting to study the role of Pt on the degradation of high surface area (H...

  1. Pt/C Fuel Cell Catalyst Degradation

    DEFF Research Database (Denmark)

    Zana, Alessandro

    This thesis investigates the degradation behavior of Pt/C catalysts under simulated automotive conditions. By using the “tool box” synthesis method the Pt loading has been changed from low to high Pt loadings, therefore permitting to study the role of Pt on the degradation of high surface area (H...

  2. Lighting for remote viewing systems

    Energy Technology Data Exchange (ETDEWEB)

    Draper, J.V.

    1984-01-01

    Scenes viewed by television do not provide the same channels of information for judgement of distances as scenes viewed directly, since television eliminates or degrades several depth perception cues. However, it may be possible to improve depth perception of televised scenes by enhancing the information available through depth cues that are available from lighting. A literature survey and expert opinions were integrated to design a remote lighting arrangement which could enhance depth perception of operators performing remote handling operations. This paper describes the lighting arrangement and discusses some of its advantages and disadvantages. 10 references, 2 figures.

  3. Lighting for remote viewing systems

    Energy Technology Data Exchange (ETDEWEB)

    Draper, J.V.

    1984-01-01

    Scenes viewed by television do not provide the same channels of information for judgment of distances as scenes viewed directly, since television eliminates or degrades several depth perception cues. However, it may be possible to improve depth perception of televised scenes by enhancing the information available through depth cues that are available from lighting. A literature survey and expert opinions were integrated to design a remote lighting arrangement which could enhance depth perception of operators performing remote handling operations. This paper describes the lighting arrangement and discusses some of its advantages and disadvantages. 10 references, 2 figures.

  4. Screening of alginate degrading bacteria and optimization of fermentation conditions%一株高效褐藻胶降解菌的筛选及其发酵条件的优化

    Institute of Scientific and Technical Information of China (English)

    王霁宁; 严孝强; 杜宗军

    2012-01-01

    针对8株已知有褐藻胶降解酶活性的菌株,以褐藻酸钠为唯一碳源,驯化培养后筛选得到一株高效降解菌中华黄海杆菌QM42.经过发酵培养实验,确定其最佳产酶条件(w/v):以蛋白胨为氮源,以褐藻酸钠为碳源,褐藻酸钠浓度0.4%~0.7%,培养盐度5%~7%,培养初始pH值为7,培养温度31℃,150r/min摇床发酵72h,粗酶液酶活力达到9.74U/mL.%A screening work was carried out to get marine bacterium with high alginate lyase activity by using alginate as sole source of carbon. Strain QM42 was selected for further studies among the 8 alginate-degrading bacteria strains. Results showed that the optimal carbon and nitrogen sources for marine bacterium QM42 to produce extracellular alginate lyase were alginate and peptone, respectively. The optimal concentration of carbon source was 0.4%~0.7%(w/v). The culture temperature was 311. The initial pH value of the liquid. medium was about 7, and the salinity was 5%~7%. The optimal harvest time for extracellular alginate lyase was about 72h with 150r/min rotation. Under such conditions the marine bacterium QM42 could produce 9.74U/ml alginate lyase in crude fermentation medium.

  5. Ways of Viewing Pictorial Plasticity

    Directory of Open Access Journals (Sweden)

    Maarten W. A. Wijntjes

    2017-03-01

    Full Text Available The plastic effect is historically used to denote various forms of stereopsis. The vivid impression of depth often associated with binocular stereopsis can also be achieved in other ways, for example, using a synopter. Accounts of this go back over a hundred years. These ways of viewing all aim to diminish sensorial evidence that the picture is physically flat. Although various viewing modes have been proposed in the literature, their effects have never been compared. In the current study, we compared three viewing modes: monocular blur, synoptic viewing, and free viewing (using a placebo synopter. By designing a physical embodiment that was indistinguishable for the three experimental conditions, we kept observers naïve with respect to the differences between them; 197 observers participated in an experiment where the three viewing modes were compared by performing a rating task. Results indicate that synoptic viewing causes the largest plastic effect. Monocular blur scores lower than synoptic viewing but is still rated significantly higher than the baseline conditions. The results strengthen the idea that synoptic viewing is not due to a placebo effect. Furthermore, monocular blur has been verified for the first time as a way of experiencing the plastic effect, although the effect is smaller than synoptic viewing. We discuss the results with respect to the theoretical basis for the plastic effect. We show that current theories are not described with sufficient details to explain the differences we found.

  6. Remote viewing.

    Science.gov (United States)

    Scott, C

    1988-04-15

    Remote viewing is the supposed faculty which enables a percipient, sited in a closed room, to describe the perceptions of a remote agent visiting an unknown target site. To provide convincing demonstration of such a faculty poses a range of experimental and practical problems, especially if feedback to the percipient is allowed after each trial. The precautions needed are elaborate and troublesome; many potential loopholes have to be plugged and there will be strong temptations to relax standards, requiring exceptional discipline and dedication by the experimenters. Most reports of remote viewing experiments are rather superficial and do not permit assessment of the experimental procedures with confidence; in many cases there is clear evidence of particular loopholes left unclosed. Any serious appraisal of the evidence would have to go beyond the reports. Meanwhile the published evidence is far from compelling, and certainly insufficient to justify overthrow of well-established scientific principles.

  7. Degradação de diquat em condições de caixa d'água com e sem plantas de egéria Diquat degradation under small-tank conditions with and without egeria plants

    Directory of Open Access Journals (Sweden)

    E. Negrisoli

    2003-01-01

    navigation, fishing and power generation. The objective of this work was to study diquat degradation under small-tank conditions with and without Egeria densa and Egeria najas and in soil. This trial was carried out at Unesp (Brazil, 1999. The plots consisted of reservoirs with 300-liter water capacity, plus 20 cm soil and 5 cm sand on the bottom. Twenty branches of each Egeria species were planted. The treatments consisted of applying 6 ppm diquat (Reward under three different conditions: (i reservoirs with water only, (ii reservoirs with water and soil, and (iii reservoirs with water plant and soil. The concentration was measured spectrophotometrically (308 nm, obtaining the following curve: herbicide concentration (ppm = 0.7418 + 50.95391* A, where A= absorbance reading. The correlation coefficient was 0,9956648. Diquat half-life was 29 days after application, under condition (iii. Under condition (ii Diquat half-life was 23 days after application. Under condition (i its half-life was 18 days after application.

  8. The effects of temperature and pH bacterial degradation of latex ...

    African Journals Online (AJOL)

    The effects of temperature and pH bacterial degradation of latex paint in ... degradation of latex paint under humid condition by bacterial isolates was studied. ... can be preserved from bacterial contamination, deterioration and degradation by ...

  9. Microbial Aspects of Anaerobic BTEX Degradation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Combined with conventional methods, developments in both geochemical (delineation of redox processes) and molecular microbial methods (analysis of 16S rDNA genes and functional genes) have allowed us to study in details microorganisms and genes involved in the anaerobic degradation of benzene, toluene, ethylbenzene and xylene (BTEX) under specific redox conditions. This review summarizes recent research in this field. The potential for anaerobic BTEX degradation is widely spread. Specific groups of microorganisms appear to be involved in degradation under different redox conditions. Members of the Azoarcus/Thauera cluster perform BTEX degradation under denitrifying conditions, Geobacteraceae under Fe (III) reducing conditions and Desulfobacteriaceae under sulfate reducing conditions. The information so far obtained on biochemistry and molecular genetics of BTEX degradation indicates that each BTEX compound is funneled into the central benzyol-CoA pathway by a different peripheral pathway. The peripheral pathways of per BTEX compound show similarities among different physiological groups of microorganisms. We also describe how knowledge obtained on the microbial aspects of BTEX degradation can be used to enhance and monitor anaerobic BTEX degradation.

  10. Screening of agricultural waste straw-degrading strains and their enzyme-producing conditions%农业废弃秸秆降解菌的筛选及产酶特性研究

    Institute of Scientific and Technical Information of China (English)

    李波; 魏成熙; 文庭池; 石俊雄; 董玲玲; 郭萍

    2012-01-01

    从土壤和有机肥样品中分离出微生物菌株,经滤纸崩溃实验和透明圈实验得到了3株高效的农业废弃秸秆降解菌,分别为SA2、MA6和HA4.经鉴定,菌株SA2和MA6均为绿色木霉(Trichoderma viride),HA4为斜卧青霉(Penicillium decumbens).经拮抗实验可知,菌株SA2和HA4具有很好的兼容性,并对复合菌系(SA2+HA4)的产酶特性进行了初步研究.结果表明,复合菌系SA2+HA4在pH=6、温度30℃、接种量3%的条件下培养3d产酶最优,产酶能力明显高于单一菌株,其纤维素酶、蛋白酶和淀粉酶的活性分别达到了193.5、25.3和55.7U·mL-1.%In the study,some microbial strains were isolated from soil and manure samples.3 highly efficient straw-degrading strains,SA2,MA6 and HA4,were then obtained by the experiments of filter collapse and transparent circle method.MA6 and SA2 are Trichoderma viride,HA4 is PeniciUium decumbens in appraisal.Through the dual culture method,we found that SA2 and HA4 were in good compatibility.Experiments were also carried out for optimizing the conditions of enzyme production.The results showed that the optimal conditions of enzyme generation for SA2 + HA4 strains are the pH value of 5,the culture temperature of 30 ℃,the inoculum concentration of 3% and culture time of 72 h.Cellulase,protease and amylase activity are 193.5,25.3 and 55.7 U·mL-1,respectively.

  11. PEM fuel cell degradation

    Energy Technology Data Exchange (ETDEWEB)

    Borup, Rodney L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory

    2010-01-01

    The durability of PEM fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. While significant progress has been made in understanding degradation mechanisms and improving materials, further improvements in durability are required to meet commercialization targets. Catalyst and electrode durability remains a primary degradation mode, with much work reported on understanding how the catalyst and electrode structure degrades. Accelerated Stress Tests (ASTs) are used to rapidly evaluate component degradation, however the results are sometimes easy, and other times difficult to correlate. Tests that were developed to accelerate degradation of single components are shown to also affect other component's degradation modes. Non-ideal examples of this include ASTs examining catalyst degradation performances losses due to catalyst degradation do not always well correlate with catalyst surface area and also lead to losses in mass transport.

  12. Microbial degradation of chloro- and methylphenol mixtures under aerobic and denitrifying conditions. Regulation and interaction in a mixed culture; Mikrobieller Abbau von Chlor- und Methylphenolen im Gemisch unter aeroben und denitrifizierenden Bedingungen. Regulation und Interaktion in einer Mischkultur

    Energy Technology Data Exchange (ETDEWEB)

    Hollender, J.

    1994-12-31

    The mechanism and the regulation of the microbial aerobic degradation of chloro- and methylphenol mixtures were investigated by comparing the mixed culture enriched of these phenolic compounds with the isolated pure cultures. The degradation assays and the characterization of the central degrading enzymes involved show that the degradation potential of the mixed culture was essentially determined by the additive abilities of the three pure cultures Alcaligenes xylosoxidans subspecies denitrificans JH1, Pseudomonas stutzeri JH3 and Comamonas testosteroni JH5. Degradation of some substrate mixtures and avoidance of enrichment of metabolites can only be explained by the interaction of the pure cultures or the participation of other organisms in the mixed culture which were not further investigated. (orig.) [Deutsch] Bei den Untersuchungen zum Mechanismus und der Regulation des aeroben Abbaus von Chlor- und Methylphenolen im Gemisch stand der Vergleich zwischen der auf diesen Phenolen angereicherten Mischkultur und den daraus isolierten Reinkulturen im Vordergrund. Die Abbauversuche und die Charakterisierung der am Metabolismus beteiligten zentralen Enzyme zeigen, dass fuer das Abbaupotential der Mischkultur im wesentlichen die additiven Abbauleistungen der drei Reinkulturen Alcaligenes xylosoxidans subspecies dentrificans JH1, Pseudomonas stutzeri JH3 und Comamonas testosteroni JH5 verantwortlich sind. Der Abbau einiger Substratmischungen und die Vermeidung einer Anreicherung von Metaboliten in der Mischkultur sind jedoch nur durch eine Interaktion der Reinkulturen oder durch eine Beteiligung anderer nicht naeher untersuchter Organismen in der Mischkultur zu erklaeren. (orig.)

  13. Differences of accommodative responses between two eyes under binocular viewing condition mediated by polarizing glasses%偏光镜介导的双眼注视状态下调节反应差异性研究

    Institute of Scientific and Technical Information of China (English)

    王瑞卿; 张妍; 胡娱新; 何宇茜; 纪冬梅; 王淑荣

    2016-01-01

    目的::探讨利用偏振效应构建的3种不同注视方式下双眼调节反应的差异。方法:前瞻性对照研究。选取15名正视眼志愿者入选本试验(年龄18~38岁,男6名,女9名)。利用偏光镜和液晶显示器的偏振特性,设置3种不同的注视方式:(1)右眼能看到屏幕显示的视标,左眼无法看到;(2)右眼无法看到屏幕视标,左眼能看到;(3)双眼均能看到屏幕视标。使用红外电脑验光仪分别测量注视距离为5、2、1、0.5、0.33m时的客观验光值(以等效球镜计算),计算所有受试者在以上3种注视方式下的调节反应量。采用重复测量的方差分析和t检验比较不同注视方式下双眼调节反应的差异。结果:采用注视方式(1)(2)时,双眼在各种调节刺激下产生的调节反应有明显差异,其中使用眼(能看到屏幕视标眼)的调节反应均比未使用眼(不能看到屏幕视标眼)大(P0.05)。结论:双眼开放状态下,经常被使用眼的睫状肌处于相对紧张状态,较少使用眼则处于相对放松状态。这种调节反应的不均衡性,很可能是促发近视发生的危险因素。%AlM: To study the differences of accommodative responses between the two eyes under 3 different polarized viewing conditions.METHODS:Fifteen volunteers with emmetrope were recruited into this study ( aged 18 ~ 38 ) , 6 males and 9 females. Three different viewing conditions were set up by using polarizing glasses and liquid crystal display:(1) right eye could see the visual target on the screen, but left eye cannot see it;( 2 ) left eye could see the visual target on the screen, but right eye cannot see it;(3)both eyes could see the target. Accommodative responses were measured by infrared auto-refractor when fixating at the target at 5, 2, 1, 0. 5 and 0. 33m under the above 3 viewing conditions. The differences of accommodative responses under different viewing conditions were compared by using

  14. HIV is Now a Manageable Long-Term Condition, But What Makes it Unique? A Qualitative Study Exploring Views About Distinguishing Features from Multi-Professional HIV Specialists in North West England.

    Science.gov (United States)

    Jelliman, Pauline; Porcellato, Lorna

    HIV is evolving from a life-threatening infection to a long-term, manageable condition because of medical advances, radical changes in health and social care policy, and the impact of an aging population. However, HIV remains complex, presenting unique characteristics distinguishing it from other long-term conditions (LTCs). Our aim in this qualitative descriptive study was to identify and explore these features in the context of LTCs. A focus group (FG) method was used to gather the views and experiences of multi-professional HIV specialists who worked in North West England. Twenty-four staff participated in FGs (n = 3), which were audio recorded, manually transcribed, and thematically analyzed. We found four main themes: (a) stigma, (b) challenges faced by HIV specialists, (c) lack HIV-related knowledge, and (d) unique features, termed "stand alone." We concluded that these distinguishing features hindered full recognition and acceptance of HIV as an LTC. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  15. Variable Static Pressure Control Based on LabVIEW in VAV Air-Conditioning System%基于LabVIEW的变风量空调系统变静压控制

    Institute of Scientific and Technical Information of China (English)

    程贝贝; 任庆昌

    2011-01-01

    Aiming at the current situation that system airflow control mostly used fixed static pressure control method in VAV air-conditioning project, the variable static pressure control based on LabVIEW in VAV air-conditioning system is studied in Xi' an university of architecture & technology VAV laboratory. Compared with the fixed static pressure control mode, it verified that the variable static pressure control has energy-saving potential. It achieved good results based on RBF neural network auto-tuning PID control method.%针对目前变风量空调工程中系统风量多采用定静压控制的情况,结合西安建筑科技大学变风量空调实验室为研究平台。研究了基于LabVIEW的空调系统变静压控制。经验证,与定静压控制方式相比,变静压控制具有节能潜力。采用基于RBF神经网络自整定PID的控制方法,能取得良好的效果。

  16. Contribution of TopOwl head mounted display system in degraded visual environments

    Science.gov (United States)

    Lemoine, Olivier; François, Jean-Michel; Point, Pascal

    2013-05-01

    Piloting a rotorcraft in a Degraded Visual Environment (DVE) is a very complex task, and the evolution of the rotorcraft missions tend to augment the probability of such degraded flight conditions (increase of night flights, all-weather flights, with brownout or whiteout phenomena…). When the direct view of the external situation is degraded, the avionic system can be of great help for the crew to recover the lost visual references. TopOwl® Head Mounted Sight and Display (HMSD) system is particularly adapted to such situations, allowing the pilot to remain "eyes-out" while visualizing on a large field of view different information: a conformal enhanced image (EVS) coming from an on-board sensor, various 2D and 3D symbologies (flight, navigation, mission specific symbols), a conformal synthetic representation of the terrain (SVS), a night vision image coming from the integrated Image Intensifier Tubes, or a combination of these data, depending on the external conditions and the phase of flight, according to the pilot's choice.

  17. The effect of environmental humidity on radiation-induced degradation of carrageenans.

    Science.gov (United States)

    Sen, Murat; Toprak, Deniz; Güven, Olgun

    2014-12-19

    Better understanding of the chemistry of radiation-induced degradation is becoming of increasing importance on account of the utilization of polymeric materials in a variety of radiation environments as well as beneficial uses of degraded polymers. In this report the importance of environmental humidity on the degrading effect of radiation has been considered from the point of view of controlling the molecular weights of kappa- and iota-carrageenans. These two polysaccharides were irradiated in solid form under strictly controlled environmental humidity conditions by incubating and later irradiating the samples over saturated aqueous salt solutions of NaCl, NaNO3 and MgCl2. The degradation was followed in detail by a careful gel permeation chromatographic analysis of their respective molecular weights before and after irradiation. The chain scission yield values G(S) were found to decrease with the water adsorbed from environment at every absorbed dose in the range of 5-100 kGy. On the other hand at very high water uptakes the yield of chain scission again increases especially at low doses. The decrease in degradation yield was attributed to the plastifying effect of water trapped in between the polymer chains facilitating the macroradical recombinations thus reducing the extent of chain scission. This study showed that although carrageenans were irradiated in solid form, the difference in their water uptake from changing environmental humidity has a profound effect in controlling their molecular weights by irradiation with ionizing radiation.

  18. Degradation of microbial polyesters.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P

    2004-08-01

    Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

  19. Rising population and environmental degradation.

    Science.gov (United States)

    Mitra, A

    Environmental degradation is becoming an increasingly ominous threat to the well-being of India's population, and excessive population growth is the primary cause of environmental deterioration. Population growth increases the need to produce consumer products and this need, in turn, intensifies the trend to over-exploit and misuse environmental resources. Efforts to control population growth through contraceptive technology and the expansion of family planning services and to control environmental deterioration via technology and management will meet with little success. A prerequisite for controlling these dual problems is the improvement of living conditions for the masses. Only when individuals acquire a sense of security and have the prospect of acquiring a share in the resources of the country will they be willing to conserve and renew resources and to limit their fertility. Viewed from this prospective, various factors and trends in India can be assessed as either negative or positive. Positive factors, i.e., those which enhance economic oppotunities and security for the general population, include the recent achievement of economic grothw in the country's agricultural and industrial sectors, the growth in technological knowledge, and the expansion of the rural and urban infrastructure. Negative factors include 1) the increase in income inequality, 2) the refusal to grant distributive justice to the masses, 3) the lack of education which impedes public understanding and awareness of environmental issues and promotes under utilization of community and social services, 4) the high unemployment rate which prevents individuals from developing a sense of responsibility and self respect; and 5) the refusal of the government to establish fuel policies to halt the growing problem of deforestation. Major environmental problems include pollution and congestion associated with the geographical concentration of industry; the destruction of the forests which leads to

  20. Mechanisms of humic substances degradation by fungi

    Science.gov (United States)

    Chen, Y.; Hadar, Y.; Grinhut, T.

    2012-04-01

    . These strains were used throughout this study. This research shows that WRF are able to degrade different HA and under different culture conditions. We found that significant degradation occurred in high C/N media - conditions which are commonly present in the natural habitats of WRF. We suggest that in addition to lignin, these fungi play a crucial role during HS degradation in the environment. This work raises additional questions that are worth investigating in the future: what is the role of these fungi in dissolved organic matter degradation and its relationship to HA degradation? What is the detailed mechanism of iron reduction in Trametes sp. M23 as well as in other WRF? What is the exact involvement of hydroxyl radicals during degradation and what are the mechanisms of H2O2 production in Trametes sp. M23?

  1. Photoelectrocatalytic degradation of Rose Bengal

    Institute of Scientific and Technical Information of China (English)

    LIU Hui-ling; ZHOU Ding; LI Xiang-zhong; YUE Ping-tao

    2003-01-01

    An innovative photoelectrode, TiO2/Ti mesh electrode, was prepared by galvanostaticanodisation. The morphology and the crystalline texture of the TiO2 film on mesh electrode were examined by scanning electronic microscopy and Raman spectroscopy respectively. The examination results indicated that the structure and properties of the film depended on anodisation rate, and the anatase was the dominant component under the controlled experimental conditions. Degradation of Rose Bengal(RB) in photocatalytic(PC) and photoelectrocatalytic(PEC) reaction was investigated, the results demonstrated that electric biasing could improve the efficiency of photocatalytic reaction. The measurement results of TOC in photoelectrocatalytic degradation showed that the mineralisation of RB was complete relatively. The comparison between the degradation efficiency of RB in PEC process and that in aqueous TiO2 dispersion was conducted. The results showed that the apparent first-order rate constant of RB degradation in PEC process was larger than that in aqueous dispersion with 0.1%-0.3% TiO2 powder, but was smaller than that in aqueous dispersion with 1.0% TiO2.

  2. Updating Recursive XML Views of Relations

    DEFF Research Database (Denmark)

    Choi, Byron; Cong, Gao; Fan, Wenfei;

    2009-01-01

    that under this condition the analysis of deletions on relational views becomes PTIME while the insertion analysis is NP-complete. We develop an efficient algorithm to process relational view deletions, and a heuristic algorithm to handle view insertions. Finally, we present an experimental study to verify...

  3. Highly efficient degradation of 4-nitrophenol over the catalyst of Mn2O3/AC by microwave catalytic oxidation degradation method.

    Science.gov (United States)

    Yin, Cheng; Cai, Jinjun; Gao, Lingfei; Yin, Jingya; Zhou, Jicheng

    2016-03-15

    A new microwave catalytic oxidation process based on two kinds of catalysts, the commercially available activated carbon (AC) and Mn2O3 nanoparticle modified AC (Mn2O3/AC), was reported for the degradation of 4-nitrophenol (4-NP) without adding any oxidant. Effects of microwave power, catalyst dosage, irradiation time, and initial concentration for the degradation efficiency were studied. Results indicated that catalyst of Mn2O3/AC showed much higher catalytic activity than pure AC and Mn2O3 particles. Significantly, 4-NP degradation efficiency reached 99.6%, corresponding to 93.5% TOC removal under optimal conditions with microwave power of 400W, Mn2O3/AC dosage of 2g, reaction time of 5min, and initial concentration of 100mg/L. Hydroxyl radicals (OH) generated during catalytic reaction is the main oxidant, and O2 can not effectively improve removal rate. We proposed the microwave 'photoelectric effect' to interpret the generation of OH in view that microwave irradiation can directly excite the catalyst to produce electron-hole pairs and then transform H2O into OH on the surface of catalyst in solution. The obtained kinetic equation for microwave catalytic oxidation degradation of 4-NP was in line with pseudo-first-order kinetic model, that is, apparent rate constant increased as microwave power density increase.

  4. Watershed health assessment to monitor land degradation

    Science.gov (United States)

    Hamidreza Sadeghi, Seyed; Hazbavi, Zeinab; Cerdà, Artemi

    2017-04-01

    Land degradation is a worldwide issue that affects the Planet and the fate of the humankind (Cerdà et al., 2009; Choudhury et al., 2016; Fernández et al., 2016; Ferreira et al., 2016). Several processes affect the sustainability of the ecosystems, from soil erosion to soil compation, deforestation, Climate Change or water, soil and air pollution (Sadeghi et al., 2015a; 2015b; Gómez-Acanta et al., 2016; Mengistu et al., 2016; Mukai, 2016). Several ecosystem theories have been presented in the scientific literatures to monitor land degradation (Cerdà et al., 2016; Davudirad et al., 2016; Fava et al., 2016; Mahyou et al., 2016; Soulard et al., 2016). Besides the scientific tasks of improving the indication, the conviction of the potential users to change their concepts toward a higher consideration of ecosystem attributes, and toward a fruitful application of the health or integrity concepts, will be a main task of future activities. Reliability, resilience and vulnerability (R-R-V) indicators are often used in combination for quantifying risk and decision making in many systems. However, the use of hydrological series data for R-R-V computations has been rather limited. Toward this, the overall objective of this paper is to conduct a risk assessment analysis on stream flow discharge from Shazand Watershed located in the south western of Markazi Province in Iran for the period of 1972-2014 using R-R-V indicators. Based on the R-R-V analysis conducted in this study, the stream flow discharge of the study region followed a cyclic pattern with a decreasing trend. The results further showed a decreasing trend in reliability and resilience and an increasing trend in vulnerability in the Shazand Watershed. It may be concluded that the Shazand Watershed was in overall in unhealthy condition from view of stream flow discharge. Acknowledgements This research was funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant no. 603498 (RECARE Project

  5. 纳帕海湿地不同退化状态下土壤氮素的分异特征%Variation of Soil Nitrogen Components under different degradation condition in Napahai wetland reserve

    Institute of Scientific and Technical Information of China (English)

    胡金明; 董云霞; 袁寒; 李杰; 马彬斌

    2012-01-01

    纳帕海湿地区4类主要土壤的退化程度由高而低为弃耕地-中生草甸土(AFMMS)、中生草甸土(MMS)、湿草甸土(WMS)和沼泽土(MS),对4类土壤0~10 cm、10~20 cm、20~30 cm采样,分析全氮(TN)、速效氮(RAN)、溶解有机氮(DON)、无机氮(IN)含量。结果表明:在剖面垂向,沼泽土TN和RAN含量中上层相对富集,而DON和IN含量由上而下逐渐降低、上层相对富集;其它三类土壤氮素含量总体由上而下降低、上层相对富集;4类土壤间,上层氮素含量为AFMMS%There are 4 soil types of in Napahai wetland reserve,northwest Yunnan-Abandoned Farmland Mesophytic Meadow Soil(AFMMS),Mesophytic Meadow Soil(MMS),Wet Meadow Soil(WMS),and Marsh Soil(MS),correspondingly their degradation degrees from high to low.Contents of Total N(TN),Rapid Available N(RAN),Dissolved Organic N(DON) and Inorganic N(IN) at 3 layers(1st 0 ~ 10 cm,2nd 10 ~ 20 cm,3rd 20 ~ 30 cm) were analyzed for these 4 types of soils.Results showed that: ① From up to down in the soil profiles,contents of N components of AFMMS,MMS and WMS decreased gradually,but relatively concentrated in the 1st layer.The orders of the TN and RAN contents of MS were the 2nd layer the 1st layer the 3rd layer,which indicated relative enrichment in the 1st and 2nd layers;but the contents of DON and IN of MS decreased downwards and relatively enriched in the 1st layer.Both DON and IN accounted for very low percentages of RAN of the 4 types of soils.② Among 4 soils,the contents of N components in the 1st layer showed significant variation as AFMMS MMS WMS MS,but no obvious variation in the 2nd and 3rd layers(except the layers of MS).The significant variation of N components in the 1st layers among 4 soils revealed the effects of human disturbances within the wetland region.③ The corresponding relationship between the variation of N components in the 1st layers and the soil

  6. Bacterial Degradation of Pesticides

    DEFF Research Database (Denmark)

    Knudsen, Berith Elkær

    . Bioaugmentation i.e. addition of specific degrader organisms, has been suggested as an environmentally friendly and economically competitive strategy for cleaning polluted sites. Several organisms have been isolated, capable of degrading different compounds. However the capacity to degrade the desired compound...... SRS2, Variovorax SRS16 and Arthrobacter globiformis D47. The degradation capacity of each strain individually as well as two- and three-member consortia was studied in a sand column set up. Glass beads were added to the set up to create a dry patch, separating the organisms and the diuron-spiked sand...

  7. Comparison of Fenton, UV-Fenton and nano-Fe3O4 catalyzed UV-Fenton in degradation of phloroglucinol under neutral and alkaline conditions: Role of complexation of Fe3+ with hydroxyl group in phloroglucinol

    DEFF Research Database (Denmark)

    Wang, Yong; Lin, Xihuang; Shao, Zongze

    2017-01-01

    Phloroglucinol degradation at initial pH from 7.0 to 9.0 has been investigated in Fenton, UV-Fenton and nano-Fe3O4 catalyzed UV-Fenton (Hetero-Fenton). Within the reaction time given in this study (not more than 4 h), 150 mg·L−1 phloroglucinol was completely removed, while there was some...... difference in TOC removal efficiency: about 90% for UV-Fenton, nearly 60% for Fenton and Hetero-Fenton. Increasing initial pH from 7.0 to 9.0, there was an obvious decline in the degradation rate. The average values of H2O2 utilization efficiency were 0.65 ± 0.01 for Fenton, 0.66 ± 0.09 for UV...... important roles in Fenton degradation under neutral and alkaline pH. The result of effect of pollutant content showed phloroglucinol at lower concentrations of 20 and 50 mg·L−1 could still be completely removed by all Fenton-based systems at pH 7.0, however, in Fenton with 20 mg·L−1 phloroglucinol...

  8. Radiation degradation of alginate and chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, Naotsugu; Mitomo, Hiroshi [Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, Kiryu, Gunma (Japan); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Alginate and chitosan were irradiated in solid or aqueous solution condition with Co{sup 60} gamma rays in the dose range of 20 to 500 kGy. Degradation was observed both in solid and solution conditions. The degradation in solution was remarkably greater than that in solid. For example, the molecular weight of alginate in 4%(w/v) solution decreased from 2 x 10{sup 5} for 0 kGy to 6 x 10{sup 3} for 50 kGy irradiation while the equivalent degradation by solid irradiation required 500 kGy. The activated species from irradiated water must be responsible for the degradation in solution. The degradation was also accompanied with the color change of alginate: the color became deep brown for highly degraded alginate. UV spectra showed a distinct absorption peak at 265 nm for colored alginates, increasing with dose. The fact that discoloration of colored alginate was caused on exposure to ozone suggests a formation of double bond in pyranose-ring by scission of glycosidic bond. Degradation behavior of chitosan in irradiation was almost the same as that of alginate. (author)

  9. Autonomous valve for detection of biopolymer degradation

    DEFF Research Database (Denmark)

    Keller, Stephan Urs; Noeth, Nadine-Nicole; Fetz, Stefanie

    2009-01-01

    We present a polymer microvalve that allows the detection of biopolymer degradation without the need of external energy. The valve is based on a polymer container filled with a colored marker solution and closed by a thin lid. This structure is covered by a film of poly(L-lactide) and degradation...... of the biopolymer triggers the release of the color which is detected visually. The autonomous valve has potential for the fast testing of biopolymer degradation under various environmental conditions or by specific enzymes....

  10. CHANNEL WIDENING DURING DEGRADATION OF ALLUVIAL RIVERS

    Institute of Scientific and Technical Information of China (English)

    Guangqian WANG; Junqiang XIA

    2001-01-01

    This paper first describes the phenomenon of channel widening during degradation of alluvial rivers,explains the mechanisms of channel widening, and analyzes the stability of cohesive riverbank. Then a one-dimensional mathematical model is developed to simulate the transport of non-uniform suspended sediments, with a sub-model for the simulation of channel widening, and is used to study the process of channel widening during degradation. The effects of different incident flow and sediment conditions and different riverbank material characteristics on channel widening and bed degradation are compared.Finally, main factors that control the deformation processes are identified.

  11. Atmospheric degradation mechanism of organic sulfur compounds

    Energy Technology Data Exchange (ETDEWEB)

    Benter, T.; Arsene, C.

    2002-02-01

    In the present work a detailed product study has been performed on the OH radical initiated oxidation of dimethyl sulphide and dimethyl sulphoxide, under different conditions of temperature, partial pressure of oxygen and NO{sub x} concentration, in order to better define the degradation mechanism of the above compounds under conditions which prevail in the atmosphere. (orig.)

  12. Batteries: Imaging degradation

    Science.gov (United States)

    Shearing, Paul R.

    2016-11-01

    The degradation and failure of Li-ion batteries is strongly associated with electrode microstructure change upon (de)lithiation. Now, an operando X-ray tomography approach is shown to correlate changes in the microstructure of electrodes to cell performance, and thereby predict degradation pathways.

  13. Syntrophy in Methanogenic Degradation

    NARCIS (Netherlands)

    Worm, P.; Müller, N.; Plugge, C.M.; Stams, A.J.M.; Schink, B.

    2010-01-01

    This chapter deals with microbial communities of bacteria and archaea that closely cooperate in methanogenic degradation and perform metabolic functions in this community that neither one of them could carry out alone. The methanogenic degradation of fatty acids, alcohols, most aromatic compounds, a

  14. Rate of NDF degradation

    DEFF Research Database (Denmark)

    Weisbjerg, Martin Riis; Koukolová, V; Lund, Peter

    2007-01-01

    Degradation profiles for NDF were estimated for 83 samples of grass/grass-clover, 27 samples of cereal whole crop and 14 samples of maize whole crop.......Degradation profiles for NDF were estimated for 83 samples of grass/grass-clover, 27 samples of cereal whole crop and 14 samples of maize whole crop....

  15. Structural elucidation of gemifloxacin mesylate degradation product.

    Science.gov (United States)

    Paim, Clésio Soldateli; Führ, Fernanda; Martins, Magda Targa; Gnoatto, Simone; Bajerski, Lisiane; Garcia, Cássia Virginia; Steppe, Martin; Schapoval, Elfrides Eva Scherman

    2016-03-01

    Gemifloxacin mesylate (GFM), chemically (R,S)-7-[(4Z)-3-(aminomethyl)-4-(methoxyimino)-1-pyrrolidinyl]-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylic acid methanesulfonate, is a synthetic broad-spectrum antibacterial agent. Although many papers have been published in the literature describing the stability of fluorquinolones, little is known about the degradation products of GFM. Forced degradation studies of GFM were performed using radiation (UV-A), acid (1 mol L(-1) HCl) and alkaline conditions (0.2 mol L(-1) NaOH). The main degradation product, formed under alkaline conditions, was isolated using semi-preparative LC and structurally elucidated by nuclear magnetic resonance (proton - (1) H; carbon - (13) C; correlate spectroscopy - COSY; heteronuclear single quantum coherence - HSQC; heteronuclear multiple-bond correlation - HMBC; spectroscopy - infrared, atomic emission and mass spectrometry techniques). The degradation product isolated was characterized as sodium 7-amino-1-pyrrolidinyl-1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate, which was formed by loss of the 3-(aminomethyl)-4-(methoxyimino)-1-pyrrolidinyl ring and formation of the sodium carboxylate. The structural characterization of the degradation product was very important to understand the degradation mechanism of the GFM under alkaline conditions. In addition, the results highlight the importance of appropriate protection against hydrolysis and UV radiation during the drug-development process, storage, handling and quality control.

  16. Updating Recursive XML Views of Relations

    Institute of Scientific and Technical Information of China (English)

    Byron Choi; Gao Cong; Wenfei Fan; Stratis D. Viglas

    2008-01-01

    This paper investigates the view update problem for XML views published from relational data. We consider XML views defined in terms of mappings directed by possibly recursive DTDs compressed into DAGs and stored in relations.We provide new techniques to efficiently support XML view updates specified in terms of Xpath expressions with recursion and complex filters. The interaction between Xpath recursion and DAG compression of XML views makes the analysis of the XML view update problem rather intriguing. Furthermore, many issues are still open even for relational view updates,and need to be explored. In response to these, on the XML side, we revise the notion of side effects and update semantics based on the semantics of XML views, and present efficient algorithms to translate XML updates to relational view updates.On the relational side, we propose a mild condition on SPJ views, and show that under this condition the analysis of deletions on relational views becomes PTIME while the insertion analysis is NP-complete. We develop an efficient algorithm to process relational view deletions, and a heuristic algorithm to handle view insertions. Finally, we present an experimental study to verify the effectiveness of our techniques.

  17. 浓硫酸降解白酒丢糟制备降解糖液的条件研究%Production conditions of sugar juice from distiller′s grains of Chinese liquor by H2SO4-catalyzed degradation

    Institute of Scientific and Technical Information of China (English)

    刘跃红; 张文学; 谭力; 本田建次

    2011-01-01

    以降解白酒丢糟中的可降解多糖转化为燃料酒精为目的,通过初步研究浓硫酸对白酒丢糟中的粗纤维及粗淀粉的二次降解发现,得出干丢糟转化为还原糖的降解条件为:70%(m/m)的H2SO4与干丢糟按7:5的体积质量比混合,糊化30min,然后加水使硫酸的浓度稀释成22%(m/m)左右,在85℃的水浴条件下处理混合物1h,干丢糟的降解率可达到0.35g/g.在白酒鲜丢糟的浓硫酸降解放大试验中,用80%H2SO4与鲜丢糟干物质的体积质量比为1:1比例混合,鲜丢糟还原糖降解率亦达到0.33g/g(鲜丢糟干物质计)较高水平.%The degradable polysaccharides in distiller's grains of Chinese liquor could be degraded and converted into fuel ethanol For this purpose,the secondary degradation of raw fiber and raw starch in distiller's grains by H2SO4 was studied. The degradation conditions of dry distiller's grains into reducing sugars were determined. The 70% H2SO4 and dry distiller's grains were mixed at the ratio of 7:5(v/w) and gelatinize for 30min. Then,the H2SO4 concentration was regulated to 22%(m/m) or so by adding water, followed by water-bath at 85℃ for 1h. After the above treatment, the degradation rate of dry distiller's grains reached 0.35g/g. In the pilot scale test of H2SO4-catalyzed degradation of fresh distiller's grains, the degradation rate of fresh distiller's grains was 0.33g/g(using the dry matter of fresh distiller's grains for calculation) when 80% H2SO4 and fresh distiller's grains were mixed at the ratio of 1:1 (v/v).

  18. Determination on Degradation Condition of Phytic Acid in Rice Bran Fermented by Bacillus Natto%纳豆芽孢杆菌发酵米糠中植酸降解的测定

    Institute of Scientific and Technical Information of China (English)

    祁红兵; 宋莉; 陈钧

    2009-01-01

    优化了植酸分析样品的前处理工艺.在64 h 发酵过程中,米糠发酵物中植酸含量随发酵时间的延长而下降,降解率为34%.%The pretreatment process for analysis sample of phytic acid was optimized. In the whole fermentation process for 64 h,the phytic acid content in fermentation broth of rice bran was decreased with the delay of fermentation time,and its degradation rate was 34%.

  19. Degradation of chlorobenzoates and chlorophenols by methanogenic consortia

    NARCIS (Netherlands)

    Ennik-Maarsen, K.

    1999-01-01

    Pollution of the environment with chlorinated organic compounds mainly results from (agro)industrial activity. In many studies, biodegradation is examined under anaerobic conditions, because highly chlorinated compounds are more easily degradable under anaerobic than under aerobic conditions. Proble

  20. Environmental Degradation: Causes and Consequences

    Directory of Open Access Journals (Sweden)

    Swati Tyagi

    2014-08-01

    Full Text Available The subject of environmental economics is at the forefront of the green debate: the environment can no longer be viewed as an entity separate from the economy. Environmental degradation is of many types and have many consequences. To address this challenge a number of studies have been conducted in both developing and developed countries applying different methods to capture health benefits from improved environmental quality. Minimizing exposure to environmental risk factors by enhancing air quality and access to improved sources of drinking and bathing water, sanitation and clean energy is found to be associated with significant health benefits and can contribute significantly to the achievement of the Millennium Development Goals of environmental sustainability, health and development. In this paper, I describe the national and global causes and consequences of environmental degradation and social injustice. This paper provides a review of the literature on studies associated with reduced environmental risk and in particular focusing on reduced air pollution, enhanced water quality and climate change mitigation.

  1. 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.

  2. Silk structure and degradation.

    Science.gov (United States)

    Liu, Bin; Song, Yu-wei; Jin, Li; Wang, Zhi-jian; Pu, De-yong; Lin, Shao-qiang; Zhou, Chan; You, Hua-jian; Ma, Yan; Li, Jin-min; Yang, Li; Sung, K L Paul; Zhang, Yao-guang

    2015-07-01

    To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk.

  3. Impact of Sensor Degradation on the MODIS NDVI Time Series

    Science.gov (United States)

    Wang, Dongdong; Morton, Douglas Christopher; Masek, Jeffrey; Wu, Aisheng; Nagol, Jyoteshwar; Xiong, Xiaoxiong; Levy, Robert; Vermote, Eric; Wolfe, Robert

    2012-01-01

    Time series of satellite data provide unparalleled information on the response of vegetation to climate variability. Detecting subtle changes in vegetation over time requires consistent satellite-based measurements. Here, the impact of sensor degradation on trend detection was evaluated using Collection 5 data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors on the Terra and Aqua platforms. For Terra MODIS, the impact of blue band (Band 3, 470 nm) degradation on simulated surface reflectance was most pronounced at near-nadir view angles, leading to a 0.001-0.004 yr-1 decline in Normalized Difference Vegetation Index (NDVI) under a range of simulated aerosol conditions and surface types. Observed trends in MODIS NDVI over North America were consistentwith simulated results,with nearly a threefold difference in negative NDVI trends derived from Terra (17.4%) and Aqua (6.7%) MODIS sensors during 2002-2010. Planned adjustments to Terra MODIS calibration for Collection 6 data reprocessing will largely eliminate this negative bias in detection of NDVI trends.

  4. SPECIFIC DEGRADATION OF WATERSHEDS

    Institute of Scientific and Technical Information of China (English)

    Boubacar KANE; Pierre Y.JULIEN

    2007-01-01

    An extensive database of reservoir sedimentation surveys throughout continental United States is compiled and analyzed to determine specific degradation SD relationships as function of mean annual rainfall R, drainage area A, and watershed slope S. The database contains 1463 field measurements and specific degradation relationships are defined as function of A, R and S. Weak trends and significant variability in the data are noticeable. Specific degradation measurements are log normally distributed with respect to R, A, and S and 95% confidence intervals are determined accordingly. The accuracy of the predictions does not significantly increase as more independent variables are added to the regression analyses.

  5. Cu2O/TiO2光催化降解罗丹明B工艺条件的研究%Study on technical conditions for photocatalytic degradation of Rhodamine B by using Cu2O/TiO2

    Institute of Scientific and Technical Information of China (English)

    孙伟; 梁光远; 赵丽平; 叶兆伟; 殷东林

    2014-01-01

    The photocatalytic degradation of soluble dye Rhodamine B by using Cu2O/TiO2 as supported catalyst and sunlight as light source has been studied. The effects of the conditions ,such as concentration of catalyst ,concentra-tion of H2O2,acidity of solution,initial concentration of reactants on the course of photocatalytic degradation of Rho-damine B are mainly investigated,so as to study the technological conditions of photocatalytic degradation. The re-sults show that Cu2O/TiO2 has pretty good degradation effect on Rhodamine B . The optimal conditions are as follows:concentration of catalyst is 1 g/L,concentration of H2O2 1.5%(volume ratio),pH 5-7. Under these condi-tions,it takes only 10 min for 5 mg/L of Rhodamine B solution to reach the degradation rate 96%.%采用负载型催化剂Cu2O/TiO2,以太阳光为光源,研究了其对可溶性染料罗丹明B的降解情况。主要考察了催化剂投加量,H2O2投加体积分数,溶液的酸度和反应物初始浓度等条件对罗丹明B催化降解过程的影响,从而研究催化降解的工艺条件。结果表明:Cu2O/TiO2对罗丹明B有较好的降解效果,其最佳工艺条件为:催化剂用量为1g/L,H2O2投加体积分数为1.5%,pH为5~7。此条件下,10 min就能使5 mg/L的罗丹明B溶液达到96%的降解率。

  6. Using Remote Sensing and GIS Techniques to Study Soil Degradation Processes in North Shaanxi Province,China

    Institute of Scientific and Technical Information of China (English)

    Mushtak Talib Jabbar

    2003-01-01

    Satellite image data and thematic map data were used to provide comprehensive views of surface-bound conditions such as soil and vegetation degradation. The current work applies a computerized parametric methodology, developed by FAO, UNEP and UNESCO to assess and evaluate soil degradation at 1: 250 000 mapping scale. The study area is located in the arid and semi-arid zone of the northern part of Shaanxi Province in China, a region with considerable agricultural potential; Landsat TM images were utilized to provide recent data on land cover and use of the area. ARC/INFO and ArcView softwares were used to manage and manipulate thematic data, to process satellite images, and tabular data source. ER mapper software is utilized to derive the normalized difference vegetation index (ND VI) values while field data to estimate soil erodibility (SE) factor. A system is established for rating soil parameters, slope, climate factor and human factor activity. The rating values serve as inputs into a modified universal soil loss equation (USLE) to calculate the present state and risk for soil degradation processes, namely soil wind erosion. The produced maps and tabular data show the risk and the present status of different soil degradation processes. The study area, in general, is exposed to high risk of wind erosion and high hazards of water erosion. Several desertification maps were produced, which reflect the desertification types persisting in the study area. Wind erosion, water erosion, vegetation degradation,physical degradation and sulinization are the basic desertification maps, and others are combinations of these basic maps. In terms of statistic analysis, 33. 75 % of the total land area (120. 330 0 ha) is considered as sand or sand dune, and not included in our analysis of desertification. About 29. 41% of the total land area has slight or moderate desertification and 37. 465 % is facing severe desertification.

  7. Chronic Conditions Dashboard

    Data.gov (United States)

    U.S. Department of Health & Human Services — The CMS Chronic Conditions Dashboard presents statistical views of information on the prevalence, utilization and Medicare spending for Medicare beneficiaries with...

  8. Photochemical degradation of crude oil in seawater

    Institute of Scientific and Technical Information of China (English)

    YANG Guipeng; ZHANG Li; SUN Xiaojing; JING Weiwen

    2006-01-01

    Photochemical degradation of crude oil in seawater is an important issue in marine environmental protection and is studied in this work. Results showed that petroleum hydrocarbons could be effectively degraded by the irradiation of high-pressure mercury light or natural sunlight. Photochemical reaction was controlled by various factors including light source, aquatic medium, heavy metal ion and photo-sensitizer. The rate of photo-degradation was fast at the initial stage of exposure, exhibiting a first-order reaction kinetic behavior. However, after irradiation for a few hours, the concentration of water-soluble fraction (WSF) of petroleum hydrocarbons stabilized. For all experimental conditions, the range of the photo-degradation rate is from 0.001 3 to 0.005 7/min.

  9. Effects of Biogenic Supplementation on Xenobiotic Degradation

    Directory of Open Access Journals (Sweden)

    Truong Van-Hieu

    2016-06-01

    Full Text Available Activated sludge acclimated to 2,4-D was used to degrade 2,4-D in batch reactions. Biogenic substrates of sucrose and peptone, in varying concentrations, separately and combined, were supplemented to the degradation reactions to find if, how and why biogenic supplementations were beneficial to the degradation of the xenobiotic. With the biogenic supplement as a variable and other reaction conditions, optimal constant supplementation schemes were found which suit as feasible ways for enhancing the degradation rate of 2,4-D. Among the number of supplementation combinations, the ones having optimal advantage were 50 mg/L of sucrose, 80 mg/L of peptone, each separately, and 20 mg/L sucrose and 40 mg/L peptone combined.

  10. Thraustochytrid protists degrade hydrocarbons

    Digital Repository Service at National Institute of Oceanography (India)

    Raikar, M.T.; Raghukumar, S.; Vani, V.; David, J.J.; Chandramohan, D.

    Although thraustochytrid protists are known to be of widespread occurrence in the sea, their hydrocarbon-degrading abilities have never been investigated. We isolated thraustochytrids from coastal waters and sediments of Goa coast by enriching MPN...

  11. Degradation of implant materials

    CERN Document Server

    Eliaz, Noam

    2012-01-01

    This book surveys the degradation of implant materials, reviewing in detail such failure mechanisms as corrosion, fatigue and wear, along with monitoring techniques. Surveys common implant biomaterials, as well as procedures for implant retrieval and analysis.

  12. Degradation of endocrine disrupting chemicals by genetic transformants with two lignin degrading enzymes in Phlebia tremellosa.

    Science.gov (United States)

    Kum, Hyunwoo; Lee, Sungsuk; Ryu, Sunhwa; Choi, Hyoung T

    2011-10-01

    A white rot fungus Phlebia tremellosa produced lignin degrading enzymes, which showed degrading activity against various recalcitrant compounds. However, manganese peroxidase (MnP) activity, one of lignin degrading enzymes, was very low in this fungus under various culture conditions. An expression vector that carried both the laccase and MnP genes was constructed using laccase genomic DNA of P. tremellosa and MnP cDNA from Polyporus brumalis. P. tremellosa was genetically transformed using the expression vector to obtain fungal transformants showing increased laccase and MnP activity. Many transformants showed highly increased laccase and MnP activity at the same time in liquid medium, and three of them were used to degrade endocrine disrupting chemicals. The transformant not only degraded bisphenol A and nonylphenol more rapidly but also removed the estrogenic activities of the chemicals faster than the wild type strain.

  13. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  14. Polyanhydride degradation and erosion.

    Science.gov (United States)

    Göpferich, A; Tessmar, J

    2002-10-16

    It was the intention of this paper to give a survey on the degradation and erosion of polyanhydrides. Due to the multitude of polymers that have been synthesized in this class of material in recent years, it was not possible to discuss all polyanhydrides that have gained in significance based on their application. It was rather the intention to provide a broad picture on polyanhydride degradation and erosion based on the knowledge that we have from those polymers that have been intensively investigated. To reach this goal this review contains several sections. First, the foundation for an understanding of the nomenclature are laid by defining degradation and erosion which was deemed necessary because many different definitions exist in the current literature. Next, the properties of major classes of anhydrides are reviewed and the impact of geometry on degradation and erosion is discussed. A complicated issue is the control of drug release from degradable polymers. Therefore, the aspect of erosion-controlled release and drug stability inside polyanhydrides are discussed. Towards the end of the paper models are briefly reviewed that describe the erosion of polyanhydrides. Empirical models as well as Monte-Carlo-based approaches are described. Finally it is outlined how theoretical models can help to answer the question why polyanhydrides are surface eroding. A look at the microstructure and the results from these models lead to the conclusion that polyanhydrides are surface eroding due to their fast degradation. However they switch to bulk erosion once the device dimensions drop below a critical limit.

  15. High Modulus Biodegradable Polyurethanes for Vascular Stents: Evaluation of Accelerated in vitro Degradation and Cell Viability of Degradation Products.

    Science.gov (United States)

    Sgarioto, Melissa; Adhikari, Raju; Gunatillake, Pathiraja A; Moore, Tim; Patterson, John; Nagel, Marie-Danielle; Malherbe, François

    2015-01-01

    We have recently reported the mechanical properties and hydrolytic degradation behavior of a series of NovoSorb™ biodegradable polyurethanes (PUs) prepared by varying the hard segment (HS) weight percentage from 60 to 100. In this study, the in vitro degradation behavior of these PUs with and without extracellular matrix (ECM) coating was investigated under accelerated hydrolytic degradation (phosphate buffer saline; PBS/70°C) conditions. The mass loss at different time intervals and the effect of aqueous degradation products on the viability and growth of human umbilical vein endothelial cells (HUVEC) were examined. The results showed that PUs with HS 80% and below completely disintegrated leaving no visual polymer residue at 18 weeks and the degradation medium turned acidic due to the accumulation of products from the soft segment (SS) degradation. As expected the PU with the lowest HS was the fastest to degrade. The accumulated degradation products, when tested undiluted, showed viability of about 40% for HUVEC cells. However, the viability was over 80% when the solution was diluted to 50% and below. The growth of HUVEC cells is similar to but not identical to that observed with tissue culture polystyrene standard (TCPS). The results from this in vitro study suggested that the PUs in the series degraded primarily due to the SS degradation and the cell viability of the accumulated acidic degradation products showed poor viability to HUVEC cells when tested undiluted, however particles released to the degradation medium showed cell viability over 80%.

  16. Liquid chromatography and liquid chromatography-mass spectrometry analysis of donepezil degradation products

    Directory of Open Access Journals (Sweden)

    Mladenović Aleksandar R.

    2015-01-01

    Full Text Available This study describes the investigation of degradation products of donepezil (DP using stability indicating RP-HPLC method for determination of donepezil, which is a centrally acting reversible acetylcholinesterase inhibitor. In order to investigate the stability of drug and formed degradation products, a forced degradation study of drug sample and finished product under different forced degradation conditions has been conducted. Donepezil hydrochloride and donepezil tablets were subjected to stress degradation conditions recommended by International Conference on Harmonization (ICH. Donepezil hydrochloride solutions were subjected to acid and alkali hydrolysis, chemical oxidation and thermal degradation. Significant degradation was observed under alkali hydrolysis and oxidative degradation conditions. Additional degradation products were observed under the conditions of oxidative degradation. The degradation products observed during forced degradation studies were monitored using the high performance liquid chromatography (HPLC method developed. The parent method was modified in order to obtain LC-MS compatible method which was used to identify the degradation products from forced degradation samples using high resolution mass spectrometry. The mass spectrum provided the precise mass from which derived molecular formula of drug substance and degradation products formed and proved the specificity of the method unambiguously. [Projekat Ministarstva nauke Republike Srbije, br. 172013

  17. Early detection of materials degradation

    Science.gov (United States)

    Meyendorf, Norbert

    2017-02-01

    Lightweight components for transportation and aerospace applications are designed for an estimated lifecycle, taking expected mechanical and environmental loads into account. The main reason for catastrophic failure of components within the expected lifecycle are material inhomogeneities, like pores and inclusions as origin for fatigue cracks, that have not been detected by NDE. However, material degradation by designed or unexpected loading conditions or environmental impacts can accelerate the crack initiation or growth. Conventional NDE methods are usually able to detect cracks that are formed at the end of the degradation process, but methods for early detection of fatigue, creep, and corrosion are still a matter of research. For conventional materials ultrasonic, electromagnetic, or thermographic methods have been demonstrated as promising. Other approaches are focused to surface damage by using optical methods or characterization of the residual surface stresses that can significantly affect the creation of fatigue cracks. For conventional metallic materials, material models for nucleation and propagation of damage have been successfully applied for several years. Material microstructure/property relations are well established and the effect of loading conditions on the component life can be simulated. For advanced materials, for example carbon matrix composites or ceramic matrix composites, the processes of nucleation and propagation of damage is still not fully understood. For these materials NDE methods can not only be used for the periodic inspections, but can significantly contribute to the material scientific knowledge to understand and model the behavior of composite materials.

  18. Electrical condition monitoring method for polymers

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, Jr. Kenneth S. (Dahlonega, GA); Morris, Shelby J. (Hampton, VA); Masakowski, Daniel D. (Worcester, MA); Wong, Ching Ping (Duluth, GA); Luo, Shijian (Boise, ID)

    2010-02-16

    An electrical condition monitoring method utilizes measurement of electrical resistivity of a conductive composite degradation sensor to monitor environmentally induced degradation of a polymeric product such as insulated wire and cable. The degradation sensor comprises a polymeric matrix and conductive filler. The polymeric matrix may be a polymer used in the product, or it may be a polymer with degradation properties similar to that of a polymer used in the product. The method comprises a means for communicating the resistivity to a measuring instrument and a means to correlate resistivity of the degradation sensor with environmentally induced degradation of the product.

  19. Microbial degradation of herbicides.

    Science.gov (United States)

    Singh, Baljinder; Singh, Kashmir

    2016-01-01

    Herbicides remain the most effective, efficient and economical way to control weeds; and its market continues to grow even with the plethora of generic products. With the development of herbicide-tolerant crops, use of herbicides is increasing around the world that has resulted in severe contamination of the environment. The strategies are now being developed to clean these substances in an economical and eco-friendly manner. In this review, an attempt has been made to pool all the available literature on the biodegradation of key herbicides, clodinafop propargyl, 2,4-dichlorophenoxyacetic acid, atrazine, metolachlor, diuron, glyphosate, imazapyr, pendimethalin and paraquat under the following objectives: (1) to highlight the general characteristic and mode of action, (2) to enlist toxicity in animals, (3) to pool microorganisms capable of degrading herbicides, (4) to discuss the assessment of herbicides degradation by efficient microbes, (5) to highlight biodegradation pathways, (6) to discuss the molecular basis of degradation, (7) to enlist the products of herbicides under degradation process, (8) to highlight the factors effecting biodegradation of herbicides and (9) to discuss the future aspects of herbicides degradation. This review may be useful in developing safer and economic microbiological methods for cleanup of soil and water contaminated with such compounds.

  20. Effects of Electron Acceptors, Reducing Agents, and Toxic Metabolites on Anaerobic Degradation of Heterocyclic Compounds

    DEFF Research Database (Denmark)

    Licht, Dorthe; Ahring, Birgitte Kiær; Arvin, Erik

    1996-01-01

    Degradation of four heterocyclic compounds was examined under nitrate-reducing, sulphate-reducing and methanogenic conditions. Soil samples from a creosote-polluted site in Denmark were used as inoculum. Indole and quinoline were degraded under all redox conditions with the highest degradation...

  1. Flow accelerated organic coating degradation

    Science.gov (United States)

    Zhou, Qixin

    Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as

  2. Hydrocarbon degradation by Antarctic coastal bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Cavanagh, J.E. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre; CSIRO Div of Marine Research, Hobart (Australia); University of Tasmania, Hobart (Australia). Dept. of Agricultural Science; Nichols, P.D. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre; CSIRO Div. of Marine Research, Hobart (Australia); Franzmann, P.D. [CSIRO Land and Water, Wembley (Australia); McMeekin, T.A. [University of Tasmania, Hobart (Australia). Antarctic Cooperative Research Centre

    1999-07-01

    Bacterial cultures obtained through selective enrichment of beach sand collected 60 days and one year after treatment of sites in a pilot oil spill trial conducted at Airport Beach, Vestfold Hills, East Antarctica, were examined for the ability to degrade n-alkanes and phenanthrene. The effects of different hydrocarbon mixtures (Special Antarctic Blend [SAB] and BP-Visco), (fish oil [orange roughy]) and inoculation of replicate sites with water from Organic Lake, (previously shown to contain hydrocarbon-degrading bacteria) on the indigenous microbial population, were examined. Of the cultures obtained, those from sites treated with SAB and BP-Visco degraded n-alkanes most consistently and typically to the greatest extent. Two mixed cultures obtained from samples collected at 60 days and two isolates obtained from these cultures extensively degraded phenanthrene. 1-Hydroxy-naphthoic acid formed the major phenanthrene metabolite. Lower levels of salicyclic acid, 1-naphthol, 1,4-naphthaquinone and phenanthrene 9-10 dihydrodiol were detected in extracts of phenanthrene grown cultures. This study shows that under laboratory conditions indigenous Antarctica bacteria can degrade n-alkanes and the more recalcitrant polycyclic aromatic hydrocarbon, phenanthrene. The enrichment of hydrocarbon degrading microorganisms in Antarctic ecosystems exposed to hydrocarbons, is relevant for the long term fate of hydrocarbon spills in this environment. (author)

  3. Multiscale degradations of storage ring FEL optics

    CERN Document Server

    Gatto, A; Amra, C; Boccara, C; Couprie, Marie Emmanuelle; De Ninno, G; Feigl, T; Garzella, D; Grewe, M; Kaiser, N; Marsi, M; Paoloni, S; Reita, V; Roger, J P; Torchio, P; Trovò, M; Walker, R; Wille, K

    2002-01-01

    The advanced understanding of the complete degradation phenomena is crucial in order to develop robust optics for FEL. Under very harsh Synchrotron Radiation conditions, results show that multiscale wavelength damages could be observed, inducing local crystalline structure modifications of the high optical index material with a severe increase of the surface roughness.

  4. Anaerobic degradation of linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær

    2003-01-01

    increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C...

  5. 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.

  6. Photovoltaic Degradation Risk: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D. C.; Kurtz, S. R.

    2012-04-01

    The ability to accurately predict power delivery over the course of time is of vital importance to the growth of the photovoltaic (PV) industry. Important cost drivers include the efficiency with which sunlight is converted into power, how this relationship changes over time, and the uncertainty in this prediction. An accurate quantification of power decline over time, also known as degradation rate, is essential to all stakeholders - utility companies, integrators, investors, and researchers alike. In this paper we use a statistical approach based on historical data to quantify degradation rates, discern trends and quantify risks related to measurement uncertainties, number of measurements and methodologies.

  7. Anaerobic microbial degradation of organochlorine insecticides Aldrin

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, T.C.; Yen, J.H.; Wang, Y.S. [National Taiwan Univ. (Taiwan)

    2004-09-15

    Aldrin (1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-1,4-endo-exo-5,8-dimethanonnaphthalene), a cyclodiene organochlorine insecticide, was banned by nations and classified as B2 carcinogen by United States Environmental Protection Agency (EPA). Because of its chemical stability and lipophilicity, aldrin is regarded as a persistent and recalcitrant compound. Aldrin is easily adsorbed to soil and sediment after spreading to the environments, furthermore, it may be accumulated in animal's tissue or milk and then cause adverse effects by food-chain. The dissipation process of aldrin in environments has continuously been paid much attention by researchers. In general, the dissipation of aldrin has been thought as relating to three mechanisms: photo-degradation, chemical hydrolysis, and microbial degradation. And it has been well known that microbial degradation is the most important agent for breakdown of organochlorine pesticides. There has been shown that aldrin could be transformed to its metabolites, such as dieldrin or photo-dieldrin, by microorganisms under aerobic conditions, however, limited information has been shown under anaerobic conditions. For this reason, the degradation potential of aldrin by anaerobic microorganisms obtained from indigenous river sediment was evaluated, and the effect of environmental factors such as temperatures and nutrients on the aldrin degradation was also investigated in this study.

  8. 3D View of Grand Canyon, Arizona

    Science.gov (United States)

    2000-01-01

    well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.

  9. Effect of field of view and monocular viewing on angular size judgements in an outdoor scene

    Science.gov (United States)

    Denz, E. A.; Palmer, E. A.; Ellis, S. R.

    1980-01-01

    Observers typically overestimate the angular size of distant objects. Significantly, overestimations are greater in outdoor settings than in aircraft visual-scene simulators. The effect of field of view and monocular and binocular viewing conditions on angular size estimation in an outdoor field was examined. Subjects adjusted the size of a variable triangle to match the angular size of a standard triangle set at three greater distances. Goggles were used to vary the field of view from 11.5 deg to 90 deg for both monocular and binocular viewing. In addition, an unrestricted monocular and binocular viewing condition was used. It is concluded that neither restricted fields of view similar to those present in visual simulators nor the restriction of monocular viewing causes a significant loss in depth perception in outdoor settings. Thus, neither factor should significantly affect the depth realism of visual simulators.

  10. Terahertz (THz) Radar: A Solution for Degraded Visibility Environments (DVE)

    Science.gov (United States)

    2016-11-01

    AS AN OFFICIAL DEPARTMENT OF THE ARMY POSITION UNLESS SO DESIGNATED BY OTHER AUTHORIZED DOCUMENTS. TRADE NAMES USE OF TRADE NAMES OR...to compensate for environmental conditions, allowing for actionable images in Degraded Visibility Environments (DVE). 14. SUBJECT TERMS Radar...Terahertz (THz) Waves, Degraded Visibility Environments (DVE) 15. NUMBER OF PAGES 22 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT

  11. Ultrasonic Degradation of Biosynthetic Poly (3-Hydroxybutyrate-co-Hydroxyvalerate)

    Institute of Scientific and Technical Information of China (English)

    Zhang Ying; Zhong Ming; Zhuo Ren-xi; Qu Fan-qi

    2003-01-01

    In this article, ultrasonic degradation of copolymers--poly (3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) was first reported. Effect of reaction conditions on the degradation rate was investigated. By ultrasonic irradiation we find that copolymers with narrower molecular weight distributions and higher purity can be obtained in a short time and chain cleavage takes place at HV block.

  12. Bacterial Degradation of Pesticides

    DEFF Research Database (Denmark)

    Knudsen, Berith Elkær

    could potentially improve bioremediation of BAM. An important prerequisite for bioaugmentation is the potential to produce the degrader strain at large quantities within reasonable time. The aim of manuscript II, was to optimize the growth medium for Aminobacter MSH1 and to elucidate optimal growth...

  13. Starch-degrading polysaccharide monooxygenases.

    Science.gov (United States)

    Vu, Van V; Marletta, Michael A

    2016-07-01

    Polysaccharide degradation by hydrolytic enzymes glycoside hydrolases (GHs) is well known. More recently, polysaccharide monooxygenases (PMOs, also known as lytic PMOs or LPMOs) were found to oxidatively degrade various polysaccharides via a copper-dependent hydroxylation. PMOs were previously thought to be either GHs or carbohydrate binding modules (CBMs), and have been re-classified in carbohydrate active enzymes (CAZY) database as auxiliary activity (AA) families. These enzymes include cellulose-active fungal PMOs (AA9, formerly GH61), chitin- and cellulose-active bacterial PMOs (AA10, formerly CBM33), and chitin-active fungal PMOs (AA11). These PMOs significantly boost the activity of GHs under industrially relevant conditions, and thus have great potential in the biomass-based biofuel industry. PMOs that act on starch are the latest PMOs discovered (AA13), which has expanded our perspectives in PMOs studies and starch degradation. Starch-active PMOs have many common structural features and biochemical properties of the PMO superfamily, yet differ from other PMO families in several important aspects. These differences likely correlate, at least in part, to the differences in primary and higher order structures of starch and cellulose, and chitin. In this review we will discuss the discovery, structural features, biochemical and biophysical properties, and possible biological functions of starch-active PMOs, as well as their potential application in the biofuel, food, and other starch-based industries. Important questions regarding various aspects of starch-active PMOs and possible economical driving force for their future studies will also be highlighted.

  14. On the changes of the structure of perchlorate (ClO4-)-degrading bacterial communities under heterotrophic conditions%异养条件下高氯酸盐降解细菌群落变化研究

    Institute of Scientific and Technical Information of China (English)

    谢宇轩; 关翔宇; 王阳; 王鹤立

    2014-01-01

    了解特定环境中高氯酸盐(ClO4-)降解菌的群落组成,对ClO4-的降解具有重要的指导意义.通过添加醋酸盐作为电子供体降解ClO4-,利用高通量测序(HiSeq 2000)的方法获得了复杂环境中生物群落的组成,对比了降解前后菌种结构的变化.结果表明,补充醋酸盐的降解体系(Acetate Degradation,AD)将10 mg/L ClO4-降至检出限以下需100 h.降解完毕后代表性的ClO4-降解菌Dechloromonas的相对丰度为0.2%,与原始活性污泥相比无明显差别;另一典型ClO2降解菌脱氯菌属Azospira相对丰度为3.2%;一些同时参与ClO4-降解和脱氮作用的细菌如假单胞菌属Pseudomonas也有检出,相对丰度为8%.异养条件下ClO4-降解是假单胞菌属Pseudomonas和脱氨菌属Azospira起主导作用.AD体系内菌种多样性小于原始活性污泥.电子供体的加入使活性污泥类的混合体系内生物群落结构单一化,使降解基质具备了在特定环境下针对某种污染物降解的能力.

  15. Degradation of toluene-2,4-diamine by persulphate: kinetics, intermediates and degradation pathway.

    Science.gov (United States)

    Jiang, Yong-hai; Zhang, Jin-bao; Xi, Bei-dou; An, Da; Yang, Yu; Li, Ming-xiao

    2015-01-01

    In this study, the degradation of toluene-2,4-diamine (TDA) by persulphate (PS) in an aqueous solution at near-neutral pH was examined. The result showed that the degradation rate of TDA increased with increasing PS concentrations. The optimal dosage of PS in the reaction system was determined by efficiency indicator (I) coupling in the consumption of PS and decay half-life of TDA. Calculation showed that 0.74 mM of PS was the most effective dosage for TDA degradation, at that level the maximum I of 24.51 was obtained. PS can oxidize TDA for an extended reaction time period. Under neutral condition without activation, four degradation intermediates, 2,4-diamino-3-hydroxy-5-sulfonicacidtoluene, 2,4-diaminobenzaldehyde, 2,4-bis(vinylamino)benzaldehyde and 3,5-diamino-4-hydroxy-2-pentene, were identified by high-performance liquid chromatography-mass spectrometry. The tentative degradation pathway of TDA was proposed as well. It was found that hydroxyl radical played an important role in degradation of TDA with the activation of Fe2+, whereas PS anion and sulphate radicals were responsible for the degradation without activation of Fe2+.

  16. Degradation of poplar bark by Panaeolus

    Energy Technology Data Exchange (ETDEWEB)

    Scurti, J.C.; Fiussello, N.; Gullino, M.L.; Ferrara, R.

    1978-01-01

    Pure cultures of 41 strains of Paneolus were tested for their ability to break down poplar bark with a view to their possible use for biodegradation of this waste product of paper manufacture. Most strains were able to grow (slowly) on sterilized poplar bark and showed high ligninolytic activity. Some strains also showed cellulolytic action. Almost all the strains showed phenol-oxidase activity, but there was no correlation between lignin decomposition and phenol-oxidase activity. The amounts of bark degraded by the fungi were relatively small (3.2 - 13.0% loss of dry weight after six months incubation).

  17. Development of forced degradation and stability indicating studies of drugs-A review

    Institute of Scientific and Technical Information of China (English)

    Blessy Mn; Ruchi D. Patel; Prajesh N. Prajapati; Y.K. Agrawal

    2014-01-01

    Forced degradation is a degradation of new drug substance and drug product at conditions more severe than accelerated conditions. It is required to demonstrate specificity of stability indicating methods and also provides an insight into degradation pathways and degradation products of the drug substance and helps in elucidation of the structure of the degradation products. Forced degradation studies show the chemical behavior of the molecule which in turn helps in the development of formulation and package. In addition, the regulatory guidance is very general and does not explain about the performance of forced degradation studies. Thus, this review discusses the current trends in performance of forced degradation studies by providing a strategy for conducting studies on degradation mechanisms and also describes the analytical methods helpful for development of stability indicating method.

  18. 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.

  19. [Characteristics and selectivity of photocatalytic-degradation of tetracycline hydrochloride].

    Science.gov (United States)

    Song, Chen-Yi; Yin, Da-Qiang

    2014-02-01

    The photocatalytic-degradation behavior of tetracycline hydrochloride (TTC) was studied. The catalyst used was photosensitive semiconductor titanium dioxide (TiO2). The results showed that the photocatalytic degradation of TTC was well fitted to first order reaction kinetics model, and the adsorption was the control step of the whole photocatalytic-degradation process, indicating that the main degradation path was the photocatalytic reaction of TTC adsorbed on the surface of TiO2. Besides, through photocatalytic-degradation of the mixed solution of TTC and sulfamethoxazole or amoxicillin, the degradation of the two antibiotics showed obvious selectivity when the pH, TiO2 dosage and other conditions were changed.

  20. Carbamazepine degradation by photolysis and titanium dioxide photocatalysis.

    Science.gov (United States)

    Im, Jong-Kwon; Son, Hyun-Seok; Kang, Young-Min; Zoh, Kyung-Duk

    2012-07-01

    We investigated the degradation of carbamazepine by photolysis/ultraviolet (UV)-C only and titanium dioxide photocatalysis. The degradation of carbamazepine by UV-only and titanium-dioxide-only (adsorption) reactions were inefficient, however, complete degradation of carbamazepine was observed by titanium dioxide photocatalysis within 30 min. The rate of degradation increased as initial carbamazepine concentration decreased, and the removal kinetics fit well with the Langmuir-Hinshelwood model. The addition of methanol, a radical scavenger, decreased carbamazepine removal, suggesting that the hydroxide radical played an important role during carbamazepine degradation. The addition of oxygen during titanium dioxide photocatalysis accelerated hydroxide radical production, thus improving mineralization activity. The photocatalytic degradation was more efficient at a higher pH, whereas the removal of carbamazepine and acridine (a major intermediate) were more efficient under aerobic conditions. The mineralization of carbamazepine during photocatalysis produced various ionic by-products such as ammonium and nitrate by way of nitrogen dioxide.

  1. Degradation of Silicone Encapsulants in CPV Optics

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Can; Miller, David C.; Tappan, Ian A.; Dauskardt, Reinhold H.

    2016-11-21

    High efficiency multijunction solar cells in terrestrial concentrator photovoltaic (CPV) modules are becoming an increasingly cost effective and viable option in utility scale power generation. As with other utility scale photovoltaics, CPV modules need to guarantee operational lifetimes of at least 25 years. The reliability of optical elements in CPV modules poses a unique materials challenge due to the increased UV irradiance and enhanced temperature cycling associated with concentrated solar flux. The polymeric and thin film materials used in the optical elements are especially susceptible to UV damage, diurnal temperature cycling and active chemical species from the environment. We used fracture mechanics approaches to study the degradation modes including: the adhesion between the encapsulant and the cell or secondary optical element; and the cohesion of the encapsulant itself. Understanding the underlying mechanisms of materials degradation under elevated stress conditions is critical for commercialization of CPV technology and can offer unique insights into degradation modes in similar encapsulants used in other photovoltaic modules.

  2. Degradation of 5-hydroxymethylfurfural during yeast fermentation.

    Science.gov (United States)

    Akıllıoglu, Halise Gül; Mogol, Burçe Ataç; Gökmen, Vural

    2011-12-01

    5-Hydroxymethyl furfural (HMF) may occur in malt in high quantities depending on roasting conditions. However, the HMF content of different types of beers is relatively low, indicating its potential for degradation during fermentation. This study investigates the degradation kinetics of HMF in wort during fermentation by Saccharomyces cerevisiae. The results indicated that HMF decreased exponentially as fermentation progressed. The first-order degradation rate of HMF was 0.693 × 10(-2) and 1.397 × 10(-2)min(-1) for wort and sweet wort, respectively, indicating that sugar enhances the activity of yeasts. In wort, HMF was converted into hydroxymethyl furfuryl alcohol by yeasts with a high yield (79-84% conversion). Glucose and fructose were utilised more rapidly by the yeasts in dark roasted malt than in pale malt (pfermentation medium increases this activity.

  3. Hot carrier injection degradation under dynamic stress

    Institute of Scientific and Technical Information of China (English)

    Ma Xiao-Hua; Cao Yan-Rong; Hao Yue; Zhang Yue

    2011-01-01

    In this paper, we have studied hot carrier injection (HCI) under alternant stress. Under different stress modes, different degradations are obtained from the experiment results. The different alternate stresses can reduce or enhance the HC effect, which mainly depends on the latter condition of the stress cycle. In the stress mode A (DC stress with electron injection), the degradation keeps increasing. In the stress modes B (DC stress and then stress with the smallest gate injection) and C (DC stress and then stress with hole injection under Vg=0V and Vd = 1.8 V), recovery appears in the second stress period. And in the stress mode D (DC stress and then stress with hole injection under Vg = -1.8 V and Vd = 1.8 V), as the traps filled in by holes can be smaller or greater than the generated interface states, the continued degradation or recovery in different stress periods can be obtained.

  4. Studies on adsorption, reaction mechanisms and kinetics for photocatalytic degradation of CHD, a pharmaceutical waste.

    Science.gov (United States)

    Sarkar, Santanu; Bhattacharjee, Chiranjib; Curcio, Stefano

    2015-11-01

    The photocatalytic degradation of chlorhexidine digluconate (CHD), a disinfectant and topical antiseptic and adsorption of CHD catalyst surface in dark condition has been studied. Moreover, the value of kinetic parameters has been measured and the effect of adsorption on photocatalysis has been investigated here. Substantial removal was observed during the photocatalysis process, whereas 40% removal was possible through the adsorption route on TiO2 surface. The parametric variation has shown that alkaline pH, ambient temperature, low initial substrate concentration, high TiO2 loading were favourable, though at a certain concentration of TiO2 loading, photocatalytic degradation efficiency was found to be maximum. The adsorption study has shown good confirmation with Langmuir isotherm and during the reaction at initial stage, it followed pseudo-first-order reaction, after that Langmuir Hinshelwood model was found to be appropriate in describing the system. The present study also confirmed that there is a significant effect of adsorption on photocatalytic degradation. The possible mechanism for adsorption and photocatalysis has been shown here and process controlling step has been identified. The influences of pH and temperature have been explained with the help of surface charge distribution of reacting particles and thermodynamic point of view respectively.

  5. 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) were recognized as ... 1997) and as such waste waters generated from these industrial ..... foaming and led to solvent and cell losses. In this work,.

  6. Degradation of paracetamol and other constituents in Perfalgan®

    African Journals Online (AJOL)

    1H NMR (nuclear magnetic resonance) was used to analyse the changes in ... Note: 'Standard conditions' is synonymous with 'unstressed' and 'forced degradation study' with .... Sterility may be a legitimate barrier to the clinical application of.

  7. Fault Management: Degradation Signature Detection, Modeling, and Processing Project

    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...

  8. Degradation of chlorobenzoates and chlorophenols by methanogenic consortia

    NARCIS (Netherlands)

    Ennik-Maarsen, K.

    1999-01-01

    Pollution of the environment with chlorinated organic compounds mainly results from (agro)industrial activity. In many studies, biodegradation is examined under anaerobic conditions, because highly chlorinated compounds are more easily degradable under anaerobic than under aerobic

  9. Oils degradation in agricultural machinery

    Directory of Open Access Journals (Sweden)

    Vojtěch Kumbár

    2013-01-01

    Full Text Available Evaluating of oils condition in agricultural machinery is very important. With monitoring and evaluating we can prevent technical and economic losses. In this paper there were monitored the liquid lubricants taken from mobile thresher New Holland CX 860. Chemical and viscosity degradation of the lubricants were evaluated. Temperature dependence dynamic viscosity was observed in the range of temperature from −10 °C to 80 °C (for all oils. Considerable temperature dependence dynamic viscosity was found and demonstrated in case of all samples, which is in accordance with theoretical assumptions and literature data. Mathematical models were developed and tested. Temperature dependence dynamic viscosity was modeled using a polynomial 6th degree. The proposed models can be used for prediction of flow behavior of oils.

  10. Degradation and effect of hydrogen peroxide in small-scale recirculation aquaculture system biofilters

    DEFF Research Database (Denmark)

    Møller, Martin Sune; Arvin, Erik; Pedersen, Lars-Flemming

    2010-01-01

    From an environmental point of view, hydrogen peroxide (HP) has beneficial attributes compared with other disinfectants in terms of its ready degradation and neutral by-products. The rapid degradation of HP can, however, cause difficulties with regard to safe and efficient water treatment when...

  11. Measuring global canopy reduction: A forest degradation proxy for FRA2015

    Science.gov (United States)

    Kenneth MacDicken; Erik Lidquist

    2013-01-01

    Global interest in forest degradation is widespread – but is fraught with widely differing views. Forest degradation by one definition may be sustainable forest management by another. The Global Forest Resources Assessment, conducted by FAO every five years, is working to find an approach to a global estimation of forest area that can address these differing...

  12. Oxidation and degradation of polypropylene transvaginal mesh.

    Science.gov (United States)

    Talley, Anne D; Rogers, Bridget R; Iakovlev, Vladimir; Dunn, Russell F; Guelcher, Scott A

    2017-04-01

    Polypropylene (PP) transvaginal mesh (TVM) repair for stress urinary incontinence (SUI) has shown promising short-term objective cure rates. However, life-altering complications have been associated with the placement of PP mesh for SUI repair. PP degradation as a result of the foreign body reaction (FBR) has been proposed as a contributing factor to mesh complications. We hypothesized that PP oxidizes under in vitro conditions simulating the FBR, resulting in degradation of the PP. Three PP mid-urethral slings from two commercial manufacturers were evaluated. Test specimens (n = 6) were incubated in oxidative medium for up to 5 weeks. Oxidation was assessed by Fourier Transform Infrared Spectroscopy (FTIR), and degradation was evaluated by scanning electron microscopy (SEM). FTIR spectra of the slings revealed evidence of carbonyl and hydroxyl peaks after 5 weeks of incubation time, providing evidence of oxidation of PP. SEM images at 5 weeks showed evidence of surface degradation, including pitting and flaking. Thus, oxidation and degradation of PP pelvic mesh were evidenced by chemical and physical changes under simulated in vivo conditions. To assess changes in PP surface chemistry in vivo, fibers were recovered from PP mesh explanted from a single patient without formalin fixation, untreated (n = 5) or scraped (n = 5) to remove tissue, and analyzed by X-ray photoelectron spectroscopy. Mechanical scraping removed adherent tissue, revealing an underlying layer of oxidized PP. These findings underscore the need for further research into the relative contribution of oxidative degradation to complications associated with PP-based TVM devices in larger cohorts of patients.

  13. [The degradation characteristics of degrading bacterium of 2,6-di-tert-butylphenol].

    Science.gov (United States)

    Fang, Zhen-wei; Xu, De-qiang; Zhang, Ya-lei; Xiao, Yi-ping; Zhao, Jian-fu

    2004-05-01

    A degrading bacterial strain F-3-4 for 2,6-Di-tert-butylphenol (2,6-DTBP) was isolated from biofilm in acrylic fiber wastewater treatment structures. By acclimation, its capacity for degradation of 2,6-DTBP was enhanced by 26%. It was identified as Alcaligenes sp. according to morphological, physiological and biochemical characters. By tests in shaking flasks, the effects of the conditions of growth was studied, and it was determined that the optimum conditions of growth for the strain was 37 degrees C, pH 7.0 and inoculum amount 0.1%. Under these conditions, the kinetics of degradation for 2,6-DTBP of initial concentration 100 mg/L was studied, and the result indicated that the removal rate of 2,6-DTBP within 11 days was 62.4%, and the degradation process followed Eckenfelder kinetics. The half life of 2,6-DTBP was 9.38 days. The effect of initial concentration on degradation ability of the strain also was investigated. The results showed that the optimum initial concentration was 200 mg/L. When the initial concentrations were below it, the growth of strain and removal of 2,6-DTBP increased with the increase of initial concentration, while when above the value, they were inhibited.

  14. TALSPEAK Solvent Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Leigh R. Martin; Bruce J. Mincher

    2009-09-01

    Understanding the radiolytic degradation behavior of organic molecules involved in new or existing schemes for the recycle of used nuclear fuels is of significant interest for sustaining a closed nuclear fuel cycle. Here we have conducted several lines of investigation to begin understanding the effects of radiolysis on the aqueous phase of the TALSPEAK process for the separation of the trivalent lanthanides from the trivalent actinides. Using the 60-Co irradiator at the INL, we have begun to quantify the effects of radiation on the aqueous phase complexants used in this separation technique, and how this will affect the actinide lanthanide separation factor. In addition we have started to develop methodologies for stable product identification, a key element in determining the degradation pathways. We have also introduced a methodology to investigate the effects of alpha radiolysis that has previously received limited attention.

  15. Isolation, Identification and Enzyme Producing Conditions of Poly-L-lactic Acid (PLA)-degrading Bacillus sp.Strain DSL09%1株聚乳酸降解细菌的筛选、鉴定及产酶研究

    Institute of Scientific and Technical Information of China (English)

    刘玲绯; 李凡; 林秀梅; 刘东波; 夏红梅; 陈珊

    2011-01-01

    A strain possessing activity to degrade poly-L-lactic acid ( PLA) DSL09 was screened from sludge. The strain had the effect to degrade PLA in emulsion, powder or film. It was identified as Bacillus sp. By the analyses of morphology, 16S rDNA comparison, physiological and biochemical characteristics. In order to enhance the degradation activity it was mutated with UV and obtained a genetically stable mutant strain DSL09-60b which increased PLA-degrading activity by 1.5 times of the original strain. The fermentation conditions and medium composition for the production of PLA degradase by DSL09-60b were optimized, it was tested that medium at initial pH 8.0, 0. 5% casein as inducer, 6% ( v/v) of inoculum and fermented at 37 t for 54 h the fermentation broth had the highest enzymatic activity.%从污泥中筛选出1株对聚乳酸( poly-L-lactic acid,PLA)具有降解活力的细菌DSL09,该菌株对PLA的乳化液、粉末及薄膜都具有降解作用.通过形态学、16S rDNA比对及生理生化特性的分析,鉴定该菌株属于芽胞杆菌属(Bacillus sp.).为提高该菌株对PLA的降解活力,对其进行了紫外诱变,获得了稳定遗传的突变株DSL09-60b,该突变株的PLA降解活性提高至原始菌株的1.5倍.对该突变株产PLA降解酶的发酵条件进行了优化,经测定DSL09-60b在初始培养基pH为8.0、0.5%酪蛋白为诱导物、接种量6%(体积比)的条件下37℃培养54 h时发酵液酶活性最高.

  16. Diagnostic technology for degradation of feeder pipe and fuel channel; design of nuclear fuel channel mock-up and development of signature analysis technique for its condition monitoring system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S. K. [Inha University, Incheon (Korea)

    2002-04-01

    The main purpose of this project is to design the nuclear fuel channel and to develope the signal analysis method for the nonstationary signal. The design of mock-up is necessary for the pre-test of the nuclear plant. The fault signal due to the damage of the nuclear plant is generally nonstationary. It is difficult to analysis this non-stationary signal using traditional method. Thus in this research, time-frequency analysis, and wavelet transform are studied for the analysis of nonstationary signal. Basic program for analysis of nonstationary signal embedded in the background noise is developed. Results from this research can be applied to the early detection of damage of nuclear fuel channel. However, in order to apply to the real nuclear plant, further research project should be processed through the mock-up test. Then that result can be applied to the condition monitoring of a real nuclear plant. 10 refs., 18 figs., 2 tabs. (Author)

  17. Degradable polymeric materials for osteosynthesis: Tutorial

    Directory of Open Access Journals (Sweden)

    D Eglin

    2008-12-01

    Full Text Available This report summarizes the state of the art and recent developments and advances in the use of degradable polymers devices for osteosynthesis. The current generation of biodegradable polymeric implants for bone repair utilising designs copied from metal implants, originates from the concept that devices should be supportive and as “inert” substitute to bone tissue. Today degradable polymeric devices for osteosynthesis are successful in low or mild load bearing applications. However, the lack of carefully controlled randomized prospective trials that document their efficacy in treating a particular fracture pattern is still an issue. Then, the choice between degradable and non-degradable devices must be carefully weighed and depends on many factors such as the patient age and condition, the type of fracture, the risk of infection, etc. The improvement of the biodegradable devices mechanical properties and their degradation behaviour will have to be achieved to broaden their use. The next generation of biodegradable implants will probably see the implementation of the recent gained knowledge in cell-material interactions and cells therapy, with a better control of the spatial and temporal interfaces between the material and the surrounding bone tissue.

  18. PEM Degradation Investigation Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Dan Stevenson; Lee H Spangler

    2007-11-02

    The objectives of this paper are: (1) Develop a system capable of measuring current and voltage performance for each membrane in a Polymer Electrolyte Membranes (PEM) fuel cell stack and record the performance of each individual cell; (2) Develop a single cell PEM FC to allow in situ synchrotron x-ray measurements of the cell in operation and to perform spatially resolved x-ray measurements on fuel cell elements before and after degradation; and (3) Perform initial magnetic resonance microimaging experiments on membrane materials. The Montana State University PEM Membrane Degradation program is geared towards determining how and why membranes in fuel cells degrade and fail. By monitoring every individual membrane in a fuel cell 2000 times/sec while the cell is subjected to real-world type use, we hope to: (1) cause the types of degradation users see, but in a controlled environment; (2) determine an electrical signature that will identify what causes failure, or at least warns of impending failure; (3) allows us to perform advanced x-ray and MRI characterization of the degraded membranes to provide information that may result in improvements of the membrane material; and (4) perhaps allow design of electronic control systems that will prevent fuel cells from operating under conditions where damage is likely to occur.

  19. Nonline-of-sight laser gated viewing of scattered photons

    Science.gov (United States)

    Laurenzis, Martin; Velten, Andreas

    2014-02-01

    Laser gated viewing is a prominent sensing technology for optical imaging in harsh environments and can be applied for vision through fog, smoke, and other degraded environmental conditions as well as for the vision through sea water in submarine operation. A direct imaging of nonscattered photons (or ballistic photons) is limited in range and performance by the free optical path length, i.e., the length in which a photon can propagate without interaction with scattering particles or object surfaces. The imaging and analysis of scattered photons can overcome these classical limitations and it is possible to realize a nonline-of-sight imaging. The spatial and temporal distributions of scattered photons can be analyzed by means of computational optics and their information of the scenario can be restored. In particular, the information outside the line of sight or outside the visibility range is of high interest. We demonstrate nonline-of-sight imaging with a laser gated viewing system and different illumination concepts (point and surface scattering sources).

  20. Kinetics and characteristics of phenanthrene degradation by a microbial consortium

    Institute of Scientific and Technical Information of China (English)

    Wang Jin; Xu Hongke; An Mingquan; Yan Guiwen

    2008-01-01

    The kinetics and characteristics of phenanthrene degradation by a microbial consortium W4 isolated from Henan Oilfield were investigated. The degradation percentage of solid phenanthrene at 200 mg/L in liquid medium after 6 days of incubation was higher than 95% under the condition of 37 ℃ and 120 r/min by this microbial consortium. The degradation of phenanthrene could be fitted to a first-order kinetic model with the half-life of 1.25 days. The optimum conditions for degradation of phenanthrene by consortium W4 were as follows: temperature about 37 ℃, pH from 6.0 to 7.0 and salinity about 8.0 g/L.It was concluded that microbial consortium W4 might degrade phenanthrene via both salicylic acid and o-phthalic acid pathways by analyzing products with GC-MS.

  1. Elucidating PID Degradation Mechanisms and In Situ Dark I–V Monitoring for Modeling Degradation Rate in CdTe Thin-Film Modules

    Energy Technology Data Exchange (ETDEWEB)

    Hacke, Peter; Spataru, Sergiu; Johnston, Steve; Terwilliger, Kent; VanSant, Kaitlyn; Kempe, Michael; Wohlgemuth, John; Kurtz, Sarah; Olsson, Anders; Propst, Michelle

    2016-11-01

    A progression of potential-induced degradation (PID) mechanisms are observed in CdTe modules, including shunting/junction degradation and two different manifestations of series resistance depending on the stress level and water ingress. The dark I-V method for in-situ characterization of Pmax based on superposition was adapted for the thin-film modules undergoing PID in view of the degradation mechanisms observed. An exponential model based on module temperature and relative humidity was fit to the PID rate for multiple stress levels in chamber tests and validated by predicting the observed degradation of the module type in the field.

  2. Microbial Degradation of 2,2′,4,4′-Tetrabrominated Diphenyl Ether Under Anaerobic Condition%厌氧条件下2,2',4,4'-四溴联苯醚的微生物降解

    Institute of Scientific and Technical Information of China (English)

    卢晓霞; 陈超琪; 张姝; 欧阳; 尹力; 吴蔚

    2012-01-01

    Polybrominated diphenyl ethers are emerging contaminants in the environment,among which 2,2′4,4′-tetrabrominated diphenyl ether(BDE-47) is one of the most frequently detected and the most toxic to organisms.Using BDE-47 as the object,this study investigated the degradation of BDE-47 by six enriched cultures containing Dehalococcoides species.The purpose is to understand the microbial degradation of BDE-47 under anaerobic condition and its kinetics.Serum bottles of 100 mL were used to construct the microcosms and enrich the anaerobic microorganisms.For each culture,two treatments were performed.One used BDE-47 as the only energy source with the designed concentration of 200 μg·L-1,and the other used both BDE-47 and trichloroethene(TCE) as the energy source with the designed concentrations being 200 μg·L-1 and 13 mg·L-1,respectively.After three months of experiment,two enriched cultures(6M6B and T2) could obviously degrade BDE-47,producing BDE-17 and BDE-4(and small amount of DE).The presence of TCE inhibited the degradation of BDE-47 by 6M6B and T2 cultures to a certain degree.The PCR-DGGE assay was performed to compare the microbial community structure of various enrichments and it was found that Acetobacterium sp.had good correlation with the degradation of BDE-47.Under three different initial BDE-47 concentrations(50 μg·L-1,250 μg·L-1 and 500 μg·L-1),the degradation rates of BDE-47 were 0.003 3,0.001 4 and 0.001 0 d-1,respectively.This study demonstrated that BDE-47 could be reductively degraded by bacteria under anaerobic condition,producing BDE-17 and BDE-4.Acetobacterium sp.might play an important role in the degradation of BDE-47.High concentration of BDE-47 might inhibit the activity of the BDE-47 degrading bacteria to a certain degree.%多溴联苯醚是环境中的新兴污染物,其中2,2',4,4'-四溴联苯醚(BDE-47)在环境(尤其是水环境)中普遍存在且生物毒性很高.以BDE-47

  3. Biogeochemical Cycles in Degraded Lands

    Science.gov (United States)

    Davidson, Eric A.; Vieira, Ima Celia G.; ReisdeCarvalho, Claudio Jose; DeanedeAbreuSa, Tatiana; deSouzaMoutinho, Paulo R.; Figueiredo, Ricardo O.; Stone, Thomas A.

    2004-01-01

    The objectives of this project were to define and describe the types of landscapes that fall under the broad category of "degraded lands" and to study biogeochemical cycles across this range of degradation found in secondary forests. We define degraded land as that which has lost part of its capacity of renovation of a productive ecosystem, either in the context of agroecosystems or as native communities of vegetation. This definition of degradation permits evaluation of biogeochemical constraints to future land uses.

  4. Petroleum pollutant degradation by surface water microorganisms.

    Science.gov (United States)

    Antić, Malisa P; Jovancićević, Branimir S; Ilić, Mila; Vrvić, Miroslav M; Schwarzbauer, Jan

    2006-09-01

    It is well known that the composition of petroleum or some of its processing products changes in the environment mostly under the influence of microorganisms. A series of experiments was conducted in order to define the optimum conditions for an efficient biodegradation of petroleum pollutant, or bioremediation of different segments of the environment. The aim of these investigations was to show to what extent the hydrocarbons of a petroleum pollutant are degraded by microbial cultures which were isolated as dominant microorganisms from a surface water of a wastewater canal of an oil refinery and a nitrogen plant. Biodegradation experiments were conducted on one paraffinic, and one naphthenic type of petroleum during a three month period under aerobic conditions, varying the following parameters: Inorganic (Kp) or an organic medium (Bh) with or without exposition to light. Microorganisms were analyzed in a surface water sample from a canal (Pancevo, Serbia), into which wastewater from an oil refinery and a nitrogen plant is released. The consortia of microorganisms were isolated from the water sample (most abundant species: Phormidium foveolarum--filamentous Cyanobacteria, blue-green algae and Achanthes minutissima, diatoms, algae). The simulation experiments of biodegradation were conducted with the biomass suspension and crude oils Sirakovo (Sir, paraffinic type) and Velebit (Ve, naphthenic type). After a three month period, organic substance was extracted by means of chloroform. In the extracts, the content of saturated hydrocarbons, aromatic hydrocarbons, alcohols and fatty acids was determined (the group composition). n-Alkanes and isoprenoid aliphatic alkanes, pristane and phytane, in the aliphatic fractions, were analyzed using gas chromatography (GC). Total isoprenoid aliphatic alkanes and polycyclic alkanes of sterane and triterpane types were analyzed by GC-MS. Paraffinic type petroleums have a significant loss of saturated hydrocarbons. For naphthenic

  5. 青藏高原高寒沼泽湿地在退化梯度上植物群落组成的改变对湿地水分状况的影响%Effect of change of plant community composition along degradation gradients on water conditions in an alpine swamp wetland on the Qinghai-Tibetan Plateau of China

    Institute of Scientific and Technical Information of China (English)

    李宏林; 徐当会; 杜国祯

    2012-01-01

    Aims Wetlands degradation has drawn increased concern recently. Many researchers have reported the changes of plant communities and the relevant degradation mechanism of wetlands. However, few studies have explored the effects of plant community change on the water conditions of swamp meadow. Our objective was to investigate how change of alpine swamp meadow along degradation gradients affects its water conditions. Methods The study was conducted at the Research Station of Alpine Meadow and Wetland Ecosystems of Lanzhou University (Maqu Branch Station) (33°39' N, 101°53' E). We examined 47 species (15 families) selected from a degradation gradient of alpine swamp meadow. Net photosynthesis rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) were measured simultaneously with a portable gas exchange system LI-6400 (Li-COR, Lincoln, NE, USA). Measurements were performed from 9:00 am to 12:00 am on clear days in mid-July and mid-August, using photosynthetically active radiation (PAR) = 1 800 μmol·m-2·s-1 and flow = 750 μmol·s-1. The value of water use efficiency (WUE) was determined by PJTr. We also investigated the cover of different functional groups (grasses, sedges, legumes and other forbs) at different degradation levels. Important findings The photosynthetic physiology traits were different among species and functional groups (p sedges > legumes and other forbs, and WUE was sedges > grasses > legumes and other forbs. Species composition of the plant community had been changed due to the degradation of the swamp meadow. The abundance of forbs increased with degradation. WUE was lower for forbs than other functional groups, which implied that more soil water is transpired, exacerbating the drought condition of degraded meadows. Successful restoration requires protection and replenishment of the typical native species.%对青藏高原东缘玛曲高寒沼泽湿地分属于15科的47种主要植物进行光合测定,结合对不同退化类型植

  6. QlikView scripting

    CERN Document Server

    Floyd, Matt

    2013-01-01

    This mini book offers information about QlikView scripting written in an easy-to-understand manner, and covers QlikView scripting from basic to advanced features in a compact format.If you are a basic orintermediate developer with some knowledge of QlikView applications and a basic understanding of QlikView scripting and data extraction and manipulation, this book will be great for you. If you are an advanced user, you can also use this book as a reference guide and teaching aid. If you are a QlikView project team member such as a business user, data/ETL professional, project manager, orsystem

  7. Acetogenic microbial degradation of vinyl chloride

    Science.gov (United States)

    Bradley, P.M.; Chapelle, F.H.

    2000-01-01

    Under methanogenic conditions, microbial degradation of [1,2-14C]vinyl chloride (VC) resulted in significant (14 ?? 3% maximum recovery) but transient recovery of radioactivity as 14C-acetate. Subsequently, 14C- acetate was degraded to 14CH4 and 14CO2 (18 ?? 2% and 54 ?? 3% final recoveries, respectively). In contrast, under 2-bromoethanesulfonic acid (BES) amended conditions, 14C-acetate recovery remained high (27 ?? 1% maximum recovery) throughout the study, no 14CH4 was produced, and the final recovery of 14CO2 was only 35 ?? 4%. These results demonstrate that oxidative acetogenesis may be an important mechanism for anaerobic VC biodegradation. Moreover, these results (1) demonstrate that microbial degradation of VC to CH4 and CO2 may involve oxidative acetogenesis followed by acetotrophic methanogenesis and (2) suggest that oxidative acetogenesis may be the initial step in the net oxidation of VC to CO2 reported previously under Fe(III)-reducing, SO4-reducing, and humic acids- reducing conditions.Under methanogenic conditions, microbial degradation of [1,2-14C]vinyl chloride (VC) resulted in significant (14 ?? 3% maximum recovery) but transient recovery of radioactivity as 14C-acetate. Subsequently, 14C-acetate was degraded to 14CH4 and 14CO2 (18 ?? 2% and 54 ?? 3% final recoveries respectively). In contrast, under 2-bromoethanesulfonic acid (BES) amended conditions, 14C-acetate recovery remained high (27 ?? 1% maximum recovery) throughout the study, no 14CH4 was produced, and the final rec