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Sample records for anammox process rates

  1. Effects of Inhibition Conditions on Anammox process

    Science.gov (United States)

    Xie, Haitao; Ji, Dandan; Zang, Lihua

    2017-12-01

    Anaerobic ammonium oxidation (Anammox) is a very suitable process for the treatment of nitrogen-rich wastewater, which is a promising new biological nitrogen removal process, and has a good application prospects. However, the Anammox process is inhibited by many factors, which hinders the process improvement and the application of the Anammox process. Such as organic,temperature,salts,heavy metals, phosphates, sulfides, pH and other inhibitors are usually present in practical applications. We have reviewed the previous researches on the inhibition of Anammox processes. The effect of the substrate on the anaerobic oxide is mainly caused by free ammonia or nitrite nitrogen. Most heavy metals inhibit Anammox growth and activity. The inhibition of organic matter depends on the content of organic matter and species. High salinity inhibits Anammox activity. Dissolved oxygen allows the flora to be in a balanced state. The optimum pH and temperature, as well as other factors, can provide a good growth environment for Anammox. The knowledge of inhibition on Anammox will help prevent the application and improvement of the Anammox process.

  2. Oxygen at nanomolar levels reversibly suppresses process rates and gene expression of anammox and denitrification in the oxygen minimum zone off northern Chile

    DEFF Research Database (Denmark)

    Dalsgaard, Tage; Stewart, Frank J.; Thamdrup, Bo

    2014-01-01

    UNLABELLED: A major percentage (20 to 40%) of global marine fixed-nitrogen loss occurs in oxygen minimum zones (OMZs). Concentrations of O2 and the sensitivity of the anaerobic N2-producing processes of anammox and denitrification determine where this loss occurs. We studied experimentally how O2...... at nanomolar levels affects anammox and denitrification rates and the transcription of nitrogen cycle genes in the anoxic OMZ off Chile. Rates of anammox and denitrification were reversibly suppressed, most likely at the enzyme level. Fiftypercent inhibition of N2 and N2O production by denitrification....... This O2 concentration did not suppress the transcription of other dissimilatory nitrogen cycle genes, including nitrate reductase (narG), hydrazine oxidoreductase (hzo), and nitrite reductase (nirK). However, taxonomic characterization of transcripts suggested inhibition of narG transcription...

  3. [Application and obstacles of ANAMMOX process].

    Science.gov (United States)

    Jin Rencun; Zhang, Zhengzhe; Ji, Yuxin; Chen, Hui; Guo, Qiong; Zhou, Yuhuang; Wu, Conghui; Jin, Rencun

    2014-12-01

    Anaerobic ammonium oxidation (ANAMMOX), as its essential advantages of high efficiency and low cost, is a promising novel biological nitrogen elimination process with attractive application prospects. Over the past two decades, many processes based on the ANAMMOX reaction have been continuously studied and applied to practical engineering, with the perspective of reaching 100 full-scale installations in operation worldwide by 2014. Our review summarizes various forms of ANAMMOX processes, including partial nitritation-ANAMMOX, completely autotrophic nitrogen removal over nitrite, oxygen limited autotrophic nitrification and denitrification, denitrifying ammonium oxidation, aerobic deammonification, simultaneous partial nitrification, ANAMMOX and denitrification, single-stage nitrogen removal using ANAMMOX and partial nitritation. We also compare the operating conditions for one-stage and two-stage processes and summarize the obstacles and countermeasures in engineering application of ANAMMOX systems, such as moving bed biofilm reactor, sequencing batch reactor and granular sludge reactor. Finally, we discuss the future research and application direction, which should focus on the optimization of operating conditions and applicability of the process to the actual wastewater, especially on automated control and the impact of special wastewater composition on process performance.

  4. The Increasing Interest of ANAMMOX Research in China: Bacteria, Process Development, and Application

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    Chai, Li-Yuan; Tang, Chong-Jian; Zheng, Ping; Min, Xiao-Bo; Yang, Zhi-Hui; Song, Yu-Xia

    2013-01-01

    Nitrogen pollution created severe environmental problems and increasingly has become an important issue in China. Since the first discovery of ANAMMOX in the early 1990s, this related technology has become a promising as well as sustainable bioprocess for treating strong nitrogenous wastewater. Many Chinese research groups have concentrated their efforts on the ANAMMOX research including bacteria, process development, and application during the past 20 years. A series of new and outstanding outcomes including the discovery of new ANAMMOX bacterial species (Brocadia sinica), sulfate-dependent ANAMMOX bacteria (Anammoxoglobus sulfate and Bacillus benzoevorans), and the highest nitrogen removal performance (74.3–76.7 kg-N/m3/d) in lab scale granule-based UASB reactors around the world were achieved. The characteristics, structure, packing pattern and floatation mechanism of the high-rate ANAMMOX granules in ANAMMOX reactors were also carefully illustrated by native researchers. Nowadays, some pilot and full-scale ANAMMOX reactors were constructed to treat different types of ammonium-rich wastewater including monosodium glutamate wastewater, pharmaceutical wastewater, and leachate. The prime objective of the present review is to elucidate the ongoing ANAMMOX research in China from lab scale to full scale applications, comparative analysis, and evaluation of significant findings and to set a design to usher ANAMMOX research in culmination. PMID:24381935

  5. The Increasing Interest of ANAMMOX Research in China: Bacteria, Process Development, and Application

    Directory of Open Access Journals (Sweden)

    Mohammad Ali

    2013-01-01

    Full Text Available Nitrogen pollution created severe environmental problems and increasingly has become an important issue in China. Since the first discovery of ANAMMOX in the early 1990s, this related technology has become a promising as well as sustainable bioprocess for treating strong nitrogenous wastewater. Many Chinese research groups have concentrated their efforts on the ANAMMOX research including bacteria, process development, and application during the past 20 years. A series of new and outstanding outcomes including the discovery of new ANAMMOX bacterial species (Brocadia sinica, sulfate-dependent ANAMMOX bacteria (Anammoxoglobus sulfate and Bacillus benzoevorans, and the highest nitrogen removal performance (74.3–76.7 kg-N/m3/d in lab scale granule-based UASB reactors around the world were achieved. The characteristics, structure, packing pattern and floatation mechanism of the high-rate ANAMMOX granules in ANAMMOX reactors were also carefully illustrated by native researchers. Nowadays, some pilot and full-scale ANAMMOX reactors were constructed to treat different types of ammonium-rich wastewater including monosodium glutamate wastewater, pharmaceutical wastewater, and leachate. The prime objective of the present review is to elucidate the ongoing ANAMMOX research in China from lab scale to full scale applications, comparative analysis, and evaluation of significant findings and to set a design to usher ANAMMOX research in culmination.

  6. Kinetic models for nitrogen inhibition in ANAMMOX and nitrification process on deammonification system at room temperature.

    Science.gov (United States)

    De Prá, Marina C; Kunz, Airton; Bortoli, Marcelo; Scussiato, Lucas A; Coldebella, Arlei; Vanotti, Matias; Soares, Hugo M

    2016-02-01

    In this study were fitted the best kinetic model for nitrogen removal inhibition by ammonium and/or nitrite in three different nitrogen removal systems operated at 25 °C: a nitrifying system (NF) containing only ammonia oxidizing bacteria (AOB), an ANAMMOX system (AMX) containing only ANAMMOX bacteria, and a deammonification system (DMX) containing both AOB and ANAMMOX bacteria. NF system showed inhibition by ammonium and was best described by Andrews model. The AMX system showed a strong inhibition by nitrite and Edwards model presented a best system representation. For DMX system, the increased substrate concentration (until 1060 mg NH3-N/L) tested was not limiting for the ammonia consumption rate and the Monod model was the best model to describe this process. The AOB and ANAMMOX sludges combined in the DMX system displayed a better activity, substrate affinity and excellent substrate tolerance than in nitrifying and ANAMMOX process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Enhanced nitrogen removal from pharmaceutical wastewater using SBA-ANAMMOX process.

    Science.gov (United States)

    Tang, Chong-Jian; Zheng, Ping; Chen, Ting-Ting; Zhang, Ji-Qiang; Mahmood, Qaisar; Ding, Shuang; Chen, Xiao-Guang; Chen, Jian-Wei; Wu, Da-Tian

    2011-01-01

    Efficient biological nitrogen removal from pharmaceutical wastewater has been focused recently. The present study dealt with the treatment of colistin sulfate and kitasamycin manufacturing wastewater through anaerobic ammonium oxidation (ANAMMOX). The biotoxicity assay on luminescent bacterium Photobacterium phosphoreum (T3 mutation) showed that the pharmaceutical wastewater imparted severe toxicity with a relative luminosity of 3.46% ± 0.45%. During long-term operation, the cumulative toxicity from toxic pollutants in wastewater resulted in the performance collapse of conventional ANAMMOX process. A novel ANAMMOX process with sequential biocatalyst (ANAMMOX granules) addition (SBA-ANAMMOX process) was developed by combining high-rate ANAMMOX reactor with sequential biocatalyst addition (SBA). At biocatalyst addition rate of 0.025 g VSS (L wastewater)(-1) day(-1), the nitrogen removal rate of the process reached up to 9.4 kg N m(-3) day(-1) in pharmaceutical wastewater treatment. The effluent ammonium concentration was lower than 50 mg N L(-1), which met the Discharge Standard of Water Pollutants for Pharmaceutical Industry in China (GB 21903-2008). The application of SBA-ANAMMOX process in refractory ammonium-rich wastewater is promising. Copyright © 2010 Elsevier Ltd. All rights reserved.

  8. Inhibition factors and Kinetic model for ammonium inhibition on the anammox process of the SNAD biofilm.

    Science.gov (United States)

    Zheng, Zhaoming; Li, Jun; Ma, Jing; Du, Jia; Wang, Fan; Bian, Wei; Zhang, Yanzhuo; Zhao, Baihang

    2017-03-01

    The aim of the present work was to evaluate the anaerobic ammonium oxidation (anammox) activity of simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm with different substrate concentrations and pH values. Kaldnes rings taken from the SNAD biofilm reactor were incubated in batch tests to determine the anammox activity. Haldane model was applied to investigate the ammonium inhibition on anammox process. As for nitrite inhibition, the NH 4 + -N removal rate of anammox process remained 87.4% of the maximum rate with the NO 2 - -N concentration of 100mg/L. Based on the results of Haldane model, no obvious difference in kinetic coefficients was observed under high or low free ammonia (FA) conditions, indicating that ammonium rather than FA was the true inhibitor for anammox process of SNAD biofilm. With the pH value of 7.0, the r max , Ks and K I of ammonium were 0.209kg NO 2 - -N/kg VSS/day, 9.5mg/L and 422mg/L, respectively. The suitable pH ranges for anammox process were 5.0 to 9.0. These results indicate that the SNAD biofilm performs excellent tolerance to adverse conditions. Copyright © 2016. Published by Elsevier B.V.

  9. Impact of reactor configuration on anammox process start-up: MBR versus SBR.

    Science.gov (United States)

    Tao, Yu; Gao, Da-Wen; Fu, Yuan; Wu, Wei-Min; Ren, Nan-Qi

    2012-01-01

    Anaerobic ammonium oxidation (anammox) is an energy saving biological nitrogen removal process which was limited to slow growth rate of anammox bacteria during start-up period. This study investigated the start-up of anammox process by a laboratory sequential batch reactor (SBR) for 218 days and subsequently modified the reactor as a membrane bioreactor (MBR) for 178 days. Modification of a SBR as MBR with installation of an external membrane module resulted in acceleration of specific anammox activity by 19 times. The acceleration of specific anammox activity with MBR was further confirmed by starting-up another MBR for a 242 day period. Molecular microbial analyses showed that Candidatus "Brocadia anammoxidans" and Candidatus "Kuenenia stuttgartiensis" were the dominant species in the inocula and biomass developed in the reactor. The start-up with MBR appeared to be more effective than SBR for the enrichment of anammox bacteria due to high sludge retention property of MBR configuration. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Comprehensive study for Anammox process via multistage anaerobic baffled reactors

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    Ismail, Sherif; Tawfik, Ahmed

    2017-11-01

    Continuous anaerobic ammonia oxidation (Anammox) process in multistage anaerobic baffled (MABR) reactor was investigated. The reactor was operated for approximately 150 days at constant hydraulic retention time (HRT) of 48 h and was fed with synthetic wastewater containing nitrite and ammonium as main substrates. The MABR was inoculated with mixed culture bacteria collected from activated sludge plant (41.6 g MLSS/L and 19.1 g MLVSS/L). The MABR reactor exhibited excellent performance for the start-up of Anammox process within a period of 35 days. The start-up period was divided into four successive phases; cell lysis, lag, activity elevation and steady state. Total inorganic nitrogen (TIN) removal efficiency of 96.8± 0.9% was achieved at steady state conditions, corresponding to nitrogen removal rate (NRR) of 50.2±1.7 mg N/L·d. Moreover, the effect of HRT on the Anammox process was assessed with applying five different HRTs of (48, 38.4, 28.8, 19.2 and 9.6 h). Decreasing HRT from 48 to 9.6 h reduced the removal efficiencies of NH4-N, NO2-N and TIN from 97.7±2.2 to 49.0±9.8%, from 95.7±1.9 to 71.0±8.5% and from 96.8±0.9 to 57.9±9.1%, respectively, that corresponding to reduction in NRR from 50.8±1.2 mg N/L·d at HRT of 48 h to 32.5±5.0 mg N/L·d at HRT of 9.6 h.

  11. Comprehensive study for Anammox process via multistage anaerobic baffled reactors

    Directory of Open Access Journals (Sweden)

    Ismail Sherif

    2017-01-01

    Full Text Available Continuous anaerobic ammonia oxidation (Anammox process in multistage anaerobic baffled (MABR reactor was investigated. The reactor was operated for approximately 150 days at constant hydraulic retention time (HRT of 48 h and was fed with synthetic wastewater containing nitrite and ammonium as main substrates. The MABR was inoculated with mixed culture bacteria collected from activated sludge plant (41.6 g MLSS/L and 19.1 g MLVSS/L. The MABR reactor exhibited excellent performance for the start-up of Anammox process within a period of 35 days. The start-up period was divided into four successive phases; cell lysis, lag, activity elevation and steady state. Total inorganic nitrogen (TIN removal efficiency of 96.8± 0.9% was achieved at steady state conditions, corresponding to nitrogen removal rate (NRR of 50.2±1.7 mg N/L·d. Moreover, the effect of HRT on the Anammox process was assessed with applying five different HRTs of (48, 38.4, 28.8, 19.2 and 9.6 h. Decreasing HRT from 48 to 9.6 h reduced the removal efficiencies of NH4-N, NO2-N and TIN from 97.7±2.2 to 49.0±9.8%, from 95.7±1.9 to 71.0±8.5% and from 96.8±0.9 to 57.9±9.1%, respectively, that corresponding to reduction in NRR from 50.8±1.2 mg N/L·d at HRT of 48 h to 32.5±5.0 mg N/L·d at HRT of 9.6 h.

  12. Simultaneous Fe(III) reduction and ammonia oxidation process in Anammox sludge.

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    Li, Xiang; Huang, Yong; Liu, Heng-Wei; Wu, Chuan; Bi, Wei; Yuan, Yi; Liu, Xin

    2018-02-01

    In recent years, there have been a number of reports on the phenomenon in which ferric iron (Fe(III)) is reduced to ferrous iron [Fe(II)] in anaerobic environments, accompanied by simultaneous oxidation of ammonia to NO 2 - , NO 3 - , or N 2. However, studies on the relevant reaction characteristics and mechanisms are rare. Recently, in research on the effect of Fe(III) on the activity of Anammox sludge, excess ammonia oxidization has also been found. Hence, in the present study, Fe(III) was used to serve as the electron acceptor instead of NO 2 - , and the feasibility and characteristics of Anammox coupled to Fe(III) reduction (termed Feammox) were investigated. After 160days of cultivation, the conversion rate of ammonia in the reactor was above 80%, accompanied by the production of a large amount of NO 3 - and a small amount of NO 2 - . The total nitrogen removal rate was up to 71.8%. Furthermore, quantities of Fe(II) were detected in the sludge fluorescence in situ hybridization (FISH) and denaturated gradient gel electrophoresis (DGGE) analyses further revealed that in the sludge, some Anammox bacteria were retained, and some microbes were enriched during the acclimatization process. We thus deduced that in Anammox sludge, Fe(III) reduction takes place together with ammonia oxidation to NO 2 - and NO 3 - along with the Anammox process. Copyright © 2017. Published by Elsevier B.V.

  13. Start-up and long-term operation of the Anammox process in a fixed bed reactor (FBR) filled with novel non-woven ring carriers.

    Science.gov (United States)

    Wang, Tao; Zhang, Hanmin; Yang, Fenglin; Li, Yifei; Zhang, Guangyi

    2013-04-01

    A novel kind of non-woven ring carriers was used to improve a fixed bed reactor (FBR) as Anammox reactor. The improved FBR was operated for about 1 year. The Anammox activity occurred on day 39. On day 367, the maximum total nitrogen removal rate reached 9.2 kg Nm(-3)d(-1). FISH analysis showed that Anammox bacteria predominated in the mature sludge and accounted for 78% of the total bacteria. Phylogenetic analysis further showed that Candidatus Kuenenia stuttgartiensis occupied 70% of Anammox bacteria, which benefited keeping the stability of Anammox reactor. The FBR was proved to be a suitable reactor for start-up and long-term operation of Anammox process. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  14. ANAMMOX process start up and stabilization with an anaerobic seed in Anaerobic Membrane Bioreactor (AnMBR).

    Science.gov (United States)

    Suneethi, S; Joseph, Kurian

    2011-10-01

    ANaerobic AMMonium OXidation (ANAMMOX) process, an advanced biological nitrogen removal alternative to traditional nitrification--denitrification removes ammonia using nitrite as the electron acceptor without oxygen. The feasibility of enriching anammox bacteria from anaerobic seed culture to start up an Anaerobic Membrane Bioreactor (AnMBR) for N-removal is reported in this paper. The Anammox activity was established in the AnMBR with anaerobic digester seed culture from a Sewage Treatment Plant in batch mode with recirculation followed by semi continuous process and continuous modes of operation. The AnMBR performance under varying Nitrogen Loading Rates (NLR) and HRTs is reported for a year, in terms of nitrogen transformations to ammoniacal nitrogen, nitrite and nitrate along with hydrazine and hydroxylamine. Interestingly ANAMMOX process was evident from simultaneous Amm-N and nitrite reduction, consistent nitrate production, hydrazine and hydroxylamine presence, notable organic load reduction and bicarbonate consumption. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. The role of paraffin oil on the interaction between denitrifying anaerobic methane oxidation and Anammox processes.

    Science.gov (United States)

    Fu, Liang; Ding, Zhao-Wei; Ding, Jing; Zhang, Fang; Zeng, Raymond J

    2015-10-01

    Methane is sparingly soluble in water, resulting in a slow reaction rate in the denitrifying anaerobic methane oxidation (DAMO) process. The slow rate limits the feasibility of research to examine the interaction between the DAMO and the anaerobic ammonium oxidation (Anammox) process. In this study, optimized 5 % (v/v) paraffin oil was added as a second liquid phase to improve methane solubility in a reactor containing DAMO and Anammox microbes. After just addition, methane solubility was found to increase by 25 % and DAMO activity was enhanced. After a 100-day cultivation, the paraffin reactor showed almost two times higher consumption rates of NO3 (-) (0.2268 mmol/day) and NH4 (+) (0.1403 mmol/day), compared to the control reactor without paraffin oil. The microbes tended to distribute in the oil-water interface. The quantitative (q) PCR result showed the abundance of gene copies of DAMO archaea, DAMO bacteria, and Anammox bacteria in the paraffin reactor were higher than those in the control reactor after 1 month. Fluorescence in situ hybridization revealed that the percentages of the three microbes were 55.5 and 77.6 % in the control and paraffin reactors after 100 days, respectively. A simple model of mass balance was developed to describe the interactions between DAMO and Anammox microbes and validate the activity results. A mechanism was proposed to describe the possible way that paraffin oil enhanced DAMO activity. It is quite clear that paraffin oil enhances not only DAMO activity but also Anammox activity via the interaction between them; both NO3 (-) and NH4 (+) consumption rates were about two times those of the control.

  16. The Zeolite-Anammox Treatment Process for Nitrogen Removal from Wastewater—A Review

    Directory of Open Access Journals (Sweden)

    Mark E. Grismer

    2017-11-01

    Full Text Available Water quality in San Francisco Bay has been adversely affected by nitrogen loading from wastewater treatment plants (WWTPs discharging around the periphery of the Bay. While there is documented use of zeolites and anammox bacteria in removing ammonia and possibly nitrate during wastewater treatment, there is little information available about the combined process. Though relatively large, zeolite beds have a finite ammonium adsorption potential and require periodic re-generation depending on the wastewater nitrogen loading. Use of anammox bacteria reactors for wastewater treatment have shown that ammonium (and to some degree, nitrate can be successfully removed from the wastewater, but the reactors require careful attention to loading rates and internal redox conditions. Generally, their application has been limited to treatment of high-ammonia strength wastewater at relatively warm temperatures. Moreover, few studies are available describing commercial or full-scale application of these reactors. We briefly review the literature considering use of zeolites or anammox bacteria in wastewater treatment to set the stage for description of an integrated zeolite-anammox process used to remove both ammonium and nitrate without substrate regeneration from mainstream WWTP effluent or anaerobic digester filtrate at ambient temperatures.

  17. Substrate inhibition and concentration control in an UASB-Anammox process.

    Science.gov (United States)

    Ma, Haiyuan; Niu, Qigui; Zhang, Yanlong; He, Shilong; Li, Yu-You

    2017-08-01

    An UASB-Anammox reactor was operated for more than one year to study the process performance variations respond to the nitrogen loading rate (NLR) and substrate concentration. The IC 10 (451.1mg/L) , IC 50 (725.3mg/L) and the prospected threshold of influent total nitrogen (TN) concentration were simulated. A stable TN removal efficiency was obtained when the TN influent was controlled. The disequilibrium distribution of the substrate following the plug flow with the height of the reactor resulted in significant variations in specific Anammox activity from the bottom to the top of the reactor (348→3mgN/gVSS/d). With long term acclimation, the nitrogen removal capacity of Anammox sludge varied significantly, with the most activated sludge obtained in the bottom part a 100 times capacity greater than that of the top. A stable performance with high removal efficiency in the constructed UASB-Anammox reactor was obtained when the influent TN concentration was below 451.1mg/L. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns

    International Nuclear Information System (INIS)

    Tang, Chong-Jian; He, Rui; Zheng, Ping; Chai, Li-Yuan; Min, Xiao-Bo

    2013-01-01

    Highlights: ► A novel model was conducted to estimate volumetric nitrogen conversion rates. ► The packing patterns of the granules in Anammox reactor are investigated. ► The simple cubic packing pattern was simulated in high-rate Anammox UASB reactor. ► Operational strategies concerning sludge concentration were proposed by the modeling. -- Abstract: A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50–55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor

  19. Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chong-Jian, E-mail: chjtangzju@yahoo.com.cn [Department of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083 (China); He, Rui; Zheng, Ping [Department of Environmental Engineering, Zhejiang University, Zijingang Campus, Hangzhou 310058 (China); Chai, Li-Yuan; Min, Xiao-Bo [Department of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083 (China)

    2013-04-15

    Highlights: ► A novel model was conducted to estimate volumetric nitrogen conversion rates. ► The packing patterns of the granules in Anammox reactor are investigated. ► The simple cubic packing pattern was simulated in high-rate Anammox UASB reactor. ► Operational strategies concerning sludge concentration were proposed by the modeling. -- Abstract: A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50–55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor.

  20. Startup of the Anammox Process in a Membrane Bioreactor (AnMBR) from Conventional Activated Sludge.

    Science.gov (United States)

    Gutwiński, P; Cema, G; Ziembińska-Buczyńska, A; Surmacz-Górska, J; Osadnik, M

    2016-12-01

      In this study, a laboratory-scale anammox process in a membrane bioreactor (AnMBR) was used to startup the anaerobic ammonium oxidation (anammox) process from conventional activated sludge. Stable operation was achieved after 125 days. From that time, nitrogen load was gradually increased. After six months, the average nitrogen removal efficiency exceeded 80%. The highest obtained special anammox activity (SAA) achieved was 0.17 g (-N + -N) (g VSS × d)-1. Fluorescent in situ hybridization also proved the presence of the anammox bacteria, typically a genus of Brocadia anammoxidans and Kuenenia stuttgartiensis.

  1. Anammox for ammonia removal from pig manure effluents: Effect of organic matter content on process performance

    DEFF Research Database (Denmark)

    Salces, Beatriz Molinuevo; García, M. C.; Karakashev, Dimitar Borisov

    2009-01-01

    The anammox process, under different organic loading rates (COD), was evaluated using a semi-continous UASB reactor at 37 degrees C. Three different substrates were used: initially, synthetic wastewater, and later, two different pig manure effluents (after UASB-post-digestion and after partial...... oxidation) diluted with synthetic wastewater. High ammonium removal was achieved, up to 92.1 +/- 4.9% for diluted UASB-post-digested effluent (95 mg COD L-1) and up to 98.5 +/- 0.8% for diluted partially oxidized effluent (121 mg COD L-1). Mass balance clearly showed that an increase in organic loading...... (from 95 mg COD L-1 to 237 mg COD L-1 and from 121 mg COD L-1 to 290 mg COD L-1 for the UASB-post-digested effluent and the partially oxidized effluent, respectively) negatively affected the anammox process and facilitated heterotrophic denitrification. Partial oxidation as a pre-treatment method...

  2. Effect of HCO3- concentration on anammox nitrogen removal rate in a moving bed biofilm reactor.

    Science.gov (United States)

    Zekker, Ivar; Rikmann, Ergo; Tenno, Toomas; Vabamäe, Priit; Kroon, Kristel; Loorits, Liis; Saluste, Alar; Tenno, Taavo

    2012-01-01

    Anammox biomass enriched in a moving bed biofilm reactor (MBBR) fed by actual sewage sludge reject water and synthetically added NO2- was used to study the total nitrogen (TN) removal rate of the anammox process depending on bicarbonate (HCO3-) concentration. MBBR performance resulted in the maximum TN removal rate of 1100 g N m(-3) d(-1) when the optimum HCO3- concentration (910 mg L(-1)) was used. The average reaction ratio of NO2- removal, NO3- production and NH4+ removal were 1.18/0.20/1. When the HCO3- concentration was increased to 1760mg L(-1) the TN removal rate diminished to 270 g N m(-3) d(-1). The process recovered from bicarbonate inhibition within 1 week. The batch tests performed with biomass taken from the MBBR showed that for the HCO3- concentration of 615 mg L(-1) the TN removal rate was 3.3 mg N L(-1) h(-1), whereas for both lower (120 mg L(-1)) and higher (5750 mg L(-1)) HCO3- concentrations the TN removal rates were 2.3 (+/- 0.15) and 1.6 (+/- 0.12) mg N L(-1) d(-1), respectively. PCR and DGGE analyses resulted in the detection of uncultured Planctomycetales bacterium clone P4 and, surprisingly, low-oxygen-tolerant aerobic ammonia oxidizers. The ability of anammox bacteria for mixotrophy was established by diminished amounts of nitrate produced when comparing the experiments with an organic carbon source and an inorganic carbon source.

  3. Pre-concentration of ammonium to enhance treatment of wastewater using the partial nitritation/anammox process.

    Science.gov (United States)

    Owusu-Agyeman, Isaac; Malovanyy, Andriy; Plaza, Elzbieta

    2015-01-01

    The anaerobic ammonium oxidation (anammox) process is one of the most cost-effective technologies for removing excessive nitrogen compounds from effluents of wastewater treatment plants. The study was conducted to assess the feasibility of using ion exchange (IE) and reverse osmosis (RO) methods to concentrate ammonium to support partial nitritation/anammox process, which so far has been used for treating only wastewater with high concentrations of ammonium. Upflow anaerobic sludge blanket (UASB) reactor effluents with 40.40, 37.90 and 21.80 mg NH4─N/L levels were concentrated with IE method to 367.20, 329.50 and 187.50 mg NH4─N/L, respectively, which were about nine times the initial concentrations. RO method was also used to concentrate 41.0 mg NH4─N/L of UASB effluent to 163 mg NH4─N/L at volume reduction factor 5. The rates of nitrogen removal from respective RO pretreated concentrates by partial nitritation/anammox technology were 0.60, 1.10 and 0.50 g N/m2 day. The rates were largely influenced by initial nitrogen concentration. However, rates of RO concentrates were 0.74, 0.92 and 0.81 g N/m2 day even at lower initial NH4─N concentration. It was found out from the study that higher salinity decreased the rate of nitrogen removal when using partial nitritation/anammox process. Dissolved oxygen concentration of ∼1 mg/L was optimal for the operation of the partial nitritation/anammox process when treating IE and RO concentrates. The result shows that IE and RO methods can precede a partial nitritation/anammox process to enhance the treatment of wastewater with low ammonium loads.

  4. Comparison between MBR and SBR on Anammox start-up process from the conventional activated sludge.

    Science.gov (United States)

    Wang, Tao; Zhang, Hanmin; Gao, Dawen; Yang, Fenglin; Zhang, Guangyi

    2012-10-01

    Anammox start-up performances from the conventional activated sludge were compared between a MBR and SBR. Both the reactors successfully started up Anammox process. The start-up period in the MBR (59 days) was notably shorter than that in the SBR (101 days), and the max nitrogen (NH(4)(+)+NO(2)(-)) removal capacity of 345.2 mg N L(-1) d(-1) in the MBR was also higher than that of 292.0 mg N L(-1) d(-1) in the SBR. FISH analysis showed that Anammox bacteria predominated in both reactors. Phylogenetic analysis further disclosed that the MBR had the better biodiversity of Anammox bacteria and gained a higher ecological stability. Generally, the results showed that MBR exhibited a more excellent performance for Anammox start-up. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  5. Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns.

    Science.gov (United States)

    Tang, Chong-Jian; He, Rui; Zheng, Ping; Chai, Li-Yuan; Min, Xiao-Bo

    2013-04-15

    A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50-55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Ammonium removal from municipal wastewater with application of ion exchange and partial nitritation/Anammox process

    OpenAIRE

    Malovanyy, Andriy

    2014-01-01

    Nitrogen removal from municipal wastewater with application of Anammox process offers cost reduction, especially if it is combined with maximal use of organic content of wastewater for biogas production. In this study a new technology is proposed, which is based on ammonium concentration from municipal wastewater by ion exchange followed by biological removal of ammonium from the concentrated stream by partial nitritation/Anammox process. In experiments on ammonium concentration four the most...

  7. Combined SHARON and ANAMMOX processes for ammoniacal nitrogen stabilisation in landfill bioreactors.

    Science.gov (United States)

    Sri Shalini, S; Joseph, Kurian

    2018-02-01

    Stabilisation of ammoniacal nitrogen from solid waste and leachate significantly improved by combining novel processes like SHARON (single reactor system for high activity ammonia removal over nitrite) and ANAMMOX (anaerobic ammonium oxidation) with advantages of lower carbon requirements, aeration and N 2 O emissions. This paper deals with establishing combined SHARON-ANAMMOX processes in situ pilot-scale landfill bioreactors (LFBR). Molecular analysis in LFBR with changes in nitrogen, hydrazine, hydroxylamine confirmed aerobic and anaerobic ammonium oxidising bacteria (AOB & ANAMMOX) as key players in SHARON-ANAMMOX processes. In situ SHARON-ANAMMOX process was established in LFBR with total nitrogen and ammoniacal nitrogen removal efficiency of 84% and 71%, respectively at NLR of 1.2 kgN/m 3 /d in 147 d, compared to ammoniacal nitrogen removal of 49% at NLR of 1.0 kgNH 4 -N/m 3 /d in 336 d feasible in Control LFBR. Nitrogen massbalance demonstrated in situ SHARON-ANAMMOX advantageous than control LFBR with higher nitrogen transformation to N 2 (50.8%) and lower residual nitrogen in solid waste (7.7%). Copyright © 2017. Published by Elsevier Ltd.

  8. Controlling the nitrite:ammonium ratio in a SHARON reactor in view of its coupling with an Anammox process.

    Science.gov (United States)

    Volcke, E I P; van Loosdrecht, M C M; Vanrolleghem, P A

    2006-01-01

    The combined SHARON-Anammox process for treating wastewater streams with high ammonia load is the focus of this paper. In particular, partial nitritation in the SHARON reactor should be performed to such an extent that a nitrite:ammonium ratio is generated which is optimal for full conversion in an Anammox process. In the simulation studies performed in this contribution, the nitrite:ammonium ratio produced in a SHARON process with fixed volume, as well as its effect on the subsequent Anammox process, is examined for realistic influent conditions and considering both direct and indirect pH effects on the SHARON process. Several possible operating modes for the SHARON reactor, differing in control strategies for O2, pH and the produced nitrite:ammonium ratio and based on regulating the air flow rate and/or acid/base addition, are systematically evaluated. The results are quantified through an operating cost index. Best results are obtained by means of cascade feedback control of the SHARON effluent nitrite:ammonium ratio through setting an O2 set-point that is tracked by adjusting the air flow rate, combined with single loop pH control through acid/base addition.

  9. Nitrogen Loss from Pristine Carbonate-Rock Aquifers of the Hainich Critical Zone Exploratory (Germany Is Primarily Driven by Chemolithoautotrophic Anammox Processes

    Directory of Open Access Journals (Sweden)

    Swatantar Kumar

    2017-10-01

    Full Text Available Despite the high relevance of anaerobic ammonium oxidation (anammox for nitrogen loss from marine systems, its relative importance compared to denitrification has less been studied in freshwater ecosystems, and our knowledge is especially scarce for groundwater. Surprisingly, phospholipid fatty acids (PLFA-based studies identified zones with potentially active anammox bacteria within two superimposed pristine limestone aquifer assemblages of the Hainich Critical Zone Exploratory (CZE; Germany. We found anammox to contribute an estimated 83% to total nitrogen loss in suboxic groundwaters of these aquifer assemblages at rates of 3.5–4.7 nmol L−1 d−1, presumably favored over denitrification by low organic carbon availability. Transcript abundances of hzsA genes encoding hydrazine synthase exceeded nirS and nirK transcript abundances encoding denitrifier nitrite reductase by up to two orders of magnitude, providing further support of a predominance of anammox. Anammox bacteria, dominated by groups closely related to Cand. Brocadia fulgida, constituted up to 10.6% of the groundwater microbial community and were ubiquitously present across the two aquifer assemblages with indication of active anammox bacteria even in the presence of 103 μmol L−1 oxygen. Co-occurrence of hzsA and amoA gene transcripts encoding ammonia mono-oxygenase suggested coupling between aerobic and anaerobic ammonium oxidation under suboxic conditions. These results clearly demonstrate the relevance of anammox as a key process driving nitrogen loss from oligotrophic groundwater environments, which might further be enhanced through coupling with incomplete nitrification.

  10. Systematic design of an optimal control system for the SHARON-Anammox process

    DEFF Research Database (Denmark)

    Valverde Perez, Borja; Mauricio Iglesias, Miguel; Sin, Gürkan

    2016-01-01

    A systematic design of an optimal control structure for the SHARON-Anammox nitrogen removal process is studied. The methodology incorporates two novel features to assess the controllability of the design variables candidate for the regulatory control layer: (i) H- control method, which formulates...

  11. Oxygen sensitivity of anammox and coupled N-cycle processes in oxygen minimum zones.

    Science.gov (United States)

    Kalvelage, Tim; Jensen, Marlene M; Contreras, Sergio; Revsbech, Niels Peter; Lam, Phyllis; Günter, Marcel; LaRoche, Julie; Lavik, Gaute; Kuypers, Marcel M M

    2011-01-01

    Nutrient measurements indicate that 30-50% of the total nitrogen (N) loss in the ocean occurs in oxygen minimum zones (OMZs). This pelagic N-removal takes place within only ~0.1% of the ocean volume, hence moderate variations in the extent of OMZs due to global warming may have a large impact on the global N-cycle. We examined the effect of oxygen (O(2)) on anammox, NH(3) oxidation and NO(3)(-) reduction in (15)N-labeling experiments with varying O(2) concentrations (0-25 µmol L(-1)) in the Namibian and Peruvian OMZs. Our results show that O(2) is a major controlling factor for anammox activity in OMZ waters. Based on our O(2) assays we estimate the upper limit for anammox to be ~20 µmol L(-1). In contrast, NH(3) oxidation to NO(2)(-) and NO(3)(-) reduction to NO(2)(-) as the main NH(4)(+) and NO(2)(-) sources for anammox were only moderately affected by changing O(2) concentrations. Intriguingly, aerobic NH(3) oxidation was active at non-detectable concentrations of O(2), while anaerobic NO(3)(-) reduction was fully active up to at least 25 µmol L(-1) O(2). Hence, aerobic and anaerobic N-cycle pathways in OMZs can co-occur over a larger range of O(2) concentrations than previously assumed. The zone where N-loss can occur is primarily controlled by the O(2)-sensitivity of anammox itself, and not by any effects of O(2) on the tightly coupled pathways of aerobic NH(3) oxidation and NO(3)(-) reduction. With anammox bacteria in the marine environment being active at O(2) levels ~20 times higher than those known to inhibit their cultured counterparts, the oceanic volume potentially acting as a N-sink increases tenfold. The predicted expansion of OMZs may enlarge this volume even further. Our study provides the first robust estimates of O(2) sensitivities for processes directly and indirectly connected with N-loss. These are essential to assess the effects of ocean de-oxygenation on oceanic N-cycling. © 2011 Kalvelage et al.

  12. Oxygen sensitivity of anammox and coupled N-cycle processes in oxygen minimum zones.

    Directory of Open Access Journals (Sweden)

    Tim Kalvelage

    Full Text Available Nutrient measurements indicate that 30-50% of the total nitrogen (N loss in the ocean occurs in oxygen minimum zones (OMZs. This pelagic N-removal takes place within only ~0.1% of the ocean volume, hence moderate variations in the extent of OMZs due to global warming may have a large impact on the global N-cycle. We examined the effect of oxygen (O(2 on anammox, NH(3 oxidation and NO(3(- reduction in (15N-labeling experiments with varying O(2 concentrations (0-25 µmol L(-1 in the Namibian and Peruvian OMZs. Our results show that O(2 is a major controlling factor for anammox activity in OMZ waters. Based on our O(2 assays we estimate the upper limit for anammox to be ~20 µmol L(-1. In contrast, NH(3 oxidation to NO(2(- and NO(3(- reduction to NO(2(- as the main NH(4(+ and NO(2(- sources for anammox were only moderately affected by changing O(2 concentrations. Intriguingly, aerobic NH(3 oxidation was active at non-detectable concentrations of O(2, while anaerobic NO(3(- reduction was fully active up to at least 25 µmol L(-1 O(2. Hence, aerobic and anaerobic N-cycle pathways in OMZs can co-occur over a larger range of O(2 concentrations than previously assumed. The zone where N-loss can occur is primarily controlled by the O(2-sensitivity of anammox itself, and not by any effects of O(2 on the tightly coupled pathways of aerobic NH(3 oxidation and NO(3(- reduction. With anammox bacteria in the marine environment being active at O(2 levels ~20 times higher than those known to inhibit their cultured counterparts, the oceanic volume potentially acting as a N-sink increases tenfold. The predicted expansion of OMZs may enlarge this volume even further. Our study provides the first robust estimates of O(2 sensitivities for processes directly and indirectly connected with N-loss. These are essential to assess the effects of ocean de-oxygenation on oceanic N-cycling.

  13. A pilot-scale study on the start-up of partial nitrification-anammox process for anaerobic sludge digester liquor treatment.

    Science.gov (United States)

    Wang, Gang; Xu, Xiaochen; Zhou, Liang; Wang, Chao; Yang, Fenglin

    2017-10-01

    Treatment of sludge digester liquor was successfully accomplished using a pilot-scale partial nitrification-anammox (PN/A) reactor with a nitrogen removal rate (NRR) of 1.23kgN/m 3 /d. A stable and efficient PN process was attained by controlling the concentration of free ammonia (0.7-8.4mg/L) and free nitrous acid (0.02-1.0mg/L). The application of hydroxylamine played a vital role in the reactivation of anammox bacteria. The bacteria exhibited improved granule properties at a specific input power between 0.065 and 0.097kW/m 3 , and achieved a specific anammox activity (SAA) of 1.01kgN/kgVSS/d on day 148. From day 0 to 120, the heme c content in the granules increased from 0.42±0.1 to 5.77±1.0µmol/gVSS, with a corresponding increase in NRRs and SAAs. High-throughput sequencing techniques revealed that the dominant anammox bacterial genus was Candidatus Brocadia. These conclusions provide valuable information for the full-scale treatment of sludge digester liquor. Copyright © 2017. Published by Elsevier Ltd.

  14. Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor.

    Science.gov (United States)

    Ge, Huoqing; Batstone, Damien; Keller, Jurg

    2016-01-01

    The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

  15. An autotrophic nitrogen removal process: short-cut nitrification combined with ANAMMOX for treating diluted effluent from an UASB reactor fed by landfill leachate.

    Science.gov (United States)

    Liu, Jie; Zuo, Jian'e; Yang, Yang; Zhu, Shuquan; Kuang, Sulin; Wang, Kaijun

    2010-01-01

    A combined process consisting of a short-cut nitrification (SN) reactor and an anaerobic ammonium oxidation upflow anaerobic sludge bed (ANAMMOX) reactor was developed to treat the diluted effluent from an upflow anaerobic sludge bed (UASB) reactor treating high ammonium municipal landfill leachate. The SN process was performed in an aerated upflow sludge bed (AUSB) reactor (working volume 3.05 L), treating about 50% of the diluted raw wastewater. The ammonium removal efficiency and the ratio of NO2- -N to NOx- -N in the effluent were both higher than 80%, at a maximum nitrogen loading rate of 1.47 kg/(m3 x ay). The ANAMMOX process was performed in an UASB reactor (working volume 8.5 L), using the mix of SN reactor effluent and diluted raw wastewater at a ratio of 1:1. The ammonium and nitrite removal efficiency reached over 93% and 95%, respectively, after 70-day continuous operation, at a maximum total nitrogen loading rate of 0.91 kg/(m3 x day), suggesting a successful operation of the combined process. The average nitrogen loading rate of the combined system was 0.56 kg/(m3 x day), with an average total inorganic nitrogen removal efficiency 87%. The nitrogen in the effluent was mostly nitrate. The results provided important evidence for the possibility of applying SN-ANAMMOX after UASB reactor to treat municipal landfill leachate.

  16. Optimization of process performance in a granule-based anaerobic ammonium oxidation (anammox) upflow anaerobic sludge blanket (UASB) reactor.

    Science.gov (United States)

    Xing, Bao-Shan; Guo, Qiong; Zhang, Zheng-Zhe; Zhang, Jue; Wang, Hui-Zhong; Jin, Ren-Cun

    2014-10-01

    In this study, the individual and interactive effects of influent substrate concentration (TNinf), hydraulic retention time (HRT) and upflow velocity (Vup) on the performance of anaerobic ammonium oxidation (anammox) in a granule-based upflow anaerobic sludge blanket (UASB) reactor were investigated by employing response surface methodology (RSM) with a central composite design. The purpose of this work was to identify the optimal combination of TNinf, HRT and Vup with respect to the nitrogen removal efficiency (NRE) and nitrogen removal rate (NRR). The reduced cubic models developed for the responses indicated that the optimal conditions corresponded to a TNinf content of 644-728mgNL(-1), an HRT of 0.90-1.25h, and a Vup of 0.60-1.79mh(-1). The results of confirmation trials were similar to the predictions of the developed models. These results provide useful information for improving the nitrogen removal performance of the anammox process in a UASB reactor. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. O processo ANAMMOX como alternativa para tratamento de águas residuárias, contendo alta concentração de nitrogênio The ANAMMOX process as an alternative for treatment of water with high containing nitrogen

    Directory of Open Access Journals (Sweden)

    Marina B. Scheeren

    2011-12-01

    Full Text Available O aumento da escala de produção agropecuária e agroindustrial traz, como consequência, a necessidade por alternativas para a mitigação dos impactos ambientais. As cadeias produtivas de proteína animal (ex.: suinocultura, bovinocultura e avicultura produzem efluentes com elevada concentração de compostos nitrogenados. Neste contexto, o processo ANAMMOX (do inglês Anaerobic Ammonium Oxidation se constitui em uma nova estratégia de alto desempenho visando remover compostos nitrogenados de águas residuárias, agropecuárias e agroindustriais, sob condições quimiolitoautotróficas. Este artigo apresenta uma revisão bibliográfica de trabalhos publicados nos últimos 15 anos sobre estudos deste processo, discutindo sua rota metabólica, demonstrando os micro-organismos envolvidos e os parâmetros de controle do processo, além de estudos desenvolvidos no Brasil e possíveis aplicações.The increase in agriculture and agro-industrial scale production brings the necessity for alternatives to mitigate environmental impacts. The animal protein production chains (e.g. swine, cattle and poultry produce effluents with high concentration of nitrogen compounds. In this context, the ANAMMOX (Anaerobic Ammonium Oxidation process is a new strategy for nitrogen removal in a high rate from agricultural and agro-industrial wastewaters under chemolithoautotrophic conditions. This paper presents a literature review of papers published in the last 15 years about the ANAMMOX process, discussing their metabolic pathway, microorganisms, main control parameters as well as studies conducted in Brazil and application possibilities.

  18. High-rate nitrogen removal from waste brine by marine anammox bacteria in a pilot-scale UASB reactor.

    Science.gov (United States)

    Yokota, Nobuyuki; Watanabe, Yasutsugu; Tokutomi, Takaaki; Kiyokawa, Tomohiro; Hori, Tomoyuki; Ikeda, Daisuke; Song, Kang; Hosomi, Masaaki; Terada, Akihiko

    2018-02-01

    The goal of this study was to develop a startup strategy for a high-rate anaerobic ammonium oxidation (anammox) reactor to treat waste brine with high concentrations of ammonium from a natural gas plant. An upflow anaerobic sludge blanket (UASB) anammox reactor with an effective volume of 294 L was fed continuously with waste brine with a salinity of 3% and a NH 4 + concentration of 180 mg-N/L, as well as a NaNO 2 solution. By inoculating a methanogenic granular biomass as a biomass carrier, the reactor attained the maximum volumetric nitrogen removal rate (NRR) of 10.7 kg-N/m 3 /day on day 209, which was 1.7 times higher than the highest reported NRR for wastewater of comparable salinity. High-throughput sequencing of 16S rRNA gene amplicons revealed that Candidatus Scalindua wagneri was enriched successfully in granules in the UASB, and it replaced Methanosaeta and became dominant in the granule. The inhibitory effect of NO 2 - on the anammox reaction in the granules was assessed by a 15 N tracer method, and the results showed that anammox activity was maintained at 60% after exposure to 300 mg-N/L of NO 2 - for 24 h. Compared with previous studies of the susceptibilities of Candidatus Brocadia and Candidatus Kuenenia to NO 2 - , the enriched marine anammox bacteria were proven to have comparable or even higher tolerances for high NO 2 - concentrations after a long exposure.

  19. Selection of controlled variables in bioprocesses. Application to a SHARON-Anammox process for autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Valverde Perez, Borja; Sin, Gürkan

    Selecting the right controlled variables in a bioprocess is challenging since the objectives of the process (yields, product or substrate concentration) are difficult to relate with a given actuator. We apply here process control tools that can be used to assist in the selection of controlled var...... variables to the case of the SHARON-Anammox process for autotrophic nitrogen removal....

  20. Plant-wide (BSM2) evaluation of reject water treatment with a SHARON-Anammox process

    DEFF Research Database (Denmark)

    Volcke, Eveline; Gernaey, Krist; Vrecko, Darko

    2006-01-01

    treatment plant, reject water treatment with a combined SHARON-Anammox process seems a promising option. The simulation results indicate that significant improvements of the effluent quality of the main wastewater treatment plant can be realized. An economic evaluation of the different scenarios......In wastewater treatment plants (WWTPs) equipped with sludge digestion and dewatering systems, the reject water originating from these facilities contributes significantly to the nitrogen load of the activated sludge tanks, to which it is typically recycled. In this paper, the impact of reject water...... streams on the performance of a WWTP is assessed in a simulation study, using the Benchmark Simulation Model no. 2 (BSM2), that includes the processes describing sludge treatment and in this way allows for plant-wide evaluation. Comparison of performance of a WWTP without reject water with a WWTP where...

  1. Microbial community structure and biodiversity of size-fractionated granules in a partial nitritation-anammox process.

    Science.gov (United States)

    Luo, Jinghuan; Chen, Hui; Han, Xiaoyu; Sun, Yanfang; Yuan, Zhiguo; Guo, Jianhua

    2017-06-01

    The performance of a granule-based partial nitritation-anammox process is expected to be affected by the granule size distribution, but little is known about the impact of granule size on microbial community structure and diversity. To reveal how the microbial composition and diversity vary with granule size, granules from a partial nitritation-anammox reactor were size-fractionated into five classes (1.0 mm). Microbial communities and diversity in these size-fractionated granules were investigated using 16S rRNA gene high-throughput sequencing. It was found that larger granules harbor more diverse microbial communities than small granules. Both quantitative PCR and 16S rRNA gene sequencing indicated that the abundance of anammox bacteria (dominated by Candidatus Brocadia) exhibited an increasing trend with granule size. In contrast, the abundance of ammonia-oxidizing bacteria (Nitrosomonas) decreased with increasing granule size. Moreover, larger granules harbored more diverse anammox bacteria, with four genera found in the largest granules while only two with limited abundance were detected in the smallest granules. The findings highlight an important role for granule size in shaping community structure and biodiversity. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Using low frequency and intensity ultrasound to enhance start-up and operation performance of Anammox process inoculated with the conventional sludge.

    Science.gov (United States)

    Wang, Tao; Zhang, Diandian; Sun, Yating; Zhou, Shanshan; Li, Lin; Shao, Jingjing

    2018-04-01

    A lab-scale ultrasound enhancing Anammox reactor (R1) was established and irradiated once a week by ultrasound with the optimal parameter (frequency of 25 kHz, intensity of 0.2 W cm -2 and exposure time of 3 min) obtained by batch experiments. R1 and the controlled Anammox reactor (R2) without exposure to the ultrasound were operated in parallel. The start-up period of Anammox process (53 days) in R1 was shorter than that (61 days) in R2. The nitrogen loading-enhancing period (day 53-day 135) in R1 was also shorter than that (day 61-day 151) in R2. At the end of the nitrogen loading-enhancing period, NLR (0.76 kg N m -3  d -1 ) and NRR (0.68 kg N m -3  d -1 ) of R1 were both higher than NLR (0.66 kg N m -3  d -1 ) and NRR (0.56 kg N m -3  d -1 ) of R2. Moreover, The stability of Anammox process in R1 was better than that in R2. The results demonstrated that the periodical irradiation of ultrasound enhanced the start-up and operational performance of Anammox reactor. Microbial community analysis indicated that the ultrasound accelerated the microbial succession from some other bacteria to Anammox bacteria so that shorten the start-up period of Anammox process from the conventional activated sludge. It also indicated that the ultrasound strengthened the competitive advantage of Candidatus Kuenenia stuttgartiensis in Anammox bacteria of the mature sludge so as to enhance the nitrogen removal performance of the Anammox reactor under the operation condition of high nitrogen loading. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Establishment of anammox process in sludge samples collected from swine wastewater treatment system Estabelecimento do processo anammox a partir de lodo de sistema de tratamento de efluente da suinocultura

    Directory of Open Access Journals (Sweden)

    Caroline G Casagrande

    2011-12-01

    Full Text Available The high load of nitrogen present in swine wastewater is one of the biggest management challenges of the activity. The Anammox process emerges as a good alternative for biological removal of nitrogen. This study aims to acclimate sludge collected from swine effluent treatment systems to establish the Anammox process. Two sludge samples were collected at Embrapa Swine and Poultry, Concordia - SC, Brazil, one from the bottom of an inactive anaerobic pond (inoculum A and another from an aeration tank (inoculum B. Both were acclimated until the depletion of NO3-N, being subsequently inoculated in two reactors (Reactor A - Inoculum A and Reactor B - Inoculum B. The Reactor A showed activity after 110 days of operation, while the Reactor B needed 170 days. The difference in the start-up time could be explained by the different environmental conditions to which each sludge was submitted. FISH and PCR analyses confirmed the presence of microorganisms with Anammox activity, demonstrating that the sludge of swine wastewater treatment systems is a good source of inoculum for the development of the Anammox process.A elevada carga de nitrogênio presente em efluentes da suinocultura é um dos maiores desafios de manejo da atividade. O processo Anammox surge como boa alternativa para a remoção biológica desse nutriente. Este trabalho teve como objetivo aclimatar diferentes amostras de lodos de sistemas de tratamento de efluentes da suinocultura com vistas ao estabelecimento do processo Anammox. Dois inóculos foram coletados na Embrapa Suínos e Aves, Concórdia - SC, um dos quais no fundo de uma lagoa anaeróbia inativa (Inóculo A e o outro, em um tanque de aeração (Inóculo B. Ambos foram aclimatados até cessar o consumo de N-NO3- e, posteriormente, inoculados em dois reatores (Reator A - Inóculo A e Reator B - Inóculo B. O Reator A apresentou atividade, após aproximadamente 110 dias de operação, enquanto o Reator B precisou de aproximadamente

  4. Feasibility and interest of the anammox process as treatment alternative for anaerobic digester supernatants in manure processing--an overview.

    Science.gov (United States)

    Magrí, Albert; Béline, Fabrice; Dabert, Patrick

    2013-12-15

    Completely autotrophic nitrogen removal (ANR) is based on the combination of partial nitritation (PN) and anaerobic ammonium oxidation (anammox). It is a promising alternative for the subsequent treatment of biogas digester supernatants in livestock manure processing and nitrogen surplus scenarios. However, as no full-scale experiences in the treatment of manure digestates by ANR have been published to date, future field studies addressing treatment of this kind of effluent would be of great interest. Some topics to be considered in these studies would be coupling anaerobic digestion and ANR, analysis of the factors that affect the process, comparing reactor configurations, microbial ecology, gas emissions, and achieving robust performance. This paper provides an overview of published studies on ANR. Specific issues related to the applicability of the process for treating manure digestates are discussed. The energy requirements of ANR are compared with those of other technological alternatives aimed at recovering nitrogen from digester supernatants. The results of the assessment were shown to depend on the composition of the supernatant. In this regard, the PN-anammox process was shown to be more competitive than other alternatives particularly at concentrations of up to 2 kg NH4(+)-N m(-3). Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Startup of reactors for anoxic ammonium oxidation: experiences from the first full-scale anammox reactor in Rotterdam.

    Science.gov (United States)

    van der Star, Wouter R L; Abma, Wiebe R; Blommers, Dennis; Mulder, Jan-Willem; Tokutomi, Takaaki; Strous, Marc; Picioreanu, Cristian; van Loosdrecht, Mark C M

    2007-10-01

    The first full-scale anammox reactor in the world was started in Rotterdam (NL). The reactor was scaled-up directly from laboratory-scale to full-scale and treats up to 750 kg-N/d. In the initial phase of the startup, anammox conversions could not be identified by traditional methods, but quantitative PCR proved to be a reliable indicator for growth of the anammox population, indicating an anammox doubling time of 10-12 days. The experience gained during this first startup in combination with the availability of seed sludge from this reactor, will lead to a faster startup of anammox reactors in the future. The anammox reactor type employed in Rotterdam was compared to other reactor types for the anammox process. Reactors with a high specific surface area like the granular sludge reactor employed in Rotterdam provide the highest volumetric loading rates. Mass transfer of nitrite into the biofilm is limiting the conversion of those reactor types that have a lower specific surface area. Now the first full-scale commercial anammox reactor is in operation, a consistent and descriptive nomenclature is suggested for reactors in which the anammox process is employed.

  6. Occurrence, activity and contribution of anammox in some freshwater extreme environments.

    Science.gov (United States)

    Zhu, Guibing; Xia, Chao; Shanyun, Wang; Zhou, Leiliu; Liu, Lu; Zhao, Siyan

    2015-12-01

    Anaerobic ammonium oxidation (anammox) widely occurs in marine ecosystems, and it plays an important role in the global nitrogen cycle. But in freshwater ecosystems its occurrence, distribution and contribution, especially in extreme environments, are still not well known. In this study, anammox process was investigated in some extreme environments of freshwater ecosystems, such as those with high (above 75°C) and low (below -35°C) temperature, high (pH > 8) and low (pH  300 mg kg(-1) ). The polymerase chain reaction (PCR) screening results showed that anammox bacteria were widespread in the examined sediments from freshwater extreme environments. Quantitative PCR showed that the abundance of anammox bacteria ranged from 6.94 × 10(4) to 8.05 × 10(6) hydrazine synthase (hzsB) gene copies g(-1) dry soil. (15) N-labelled incubation experiments indicated the occurrence of anammox in all examined sediments and the potential anammox rates ranged from 0.02 to 6.24 nmol N g(-1)  h(-1) , with a contribution of 3.45-58.74% of the total N2 production. In summary, these results demonstrate the occurrence of anammox in these extreme environments, inferring that anammox may harbour a wide ecological niche in the freshwater ecosystems. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Nitrous oxide production in intermittently aerated Partial Nitritation-Anammox reactor: oxic N2O production dominates and relates with ammonia removal rate

    DEFF Research Database (Denmark)

    Blum, Jan-Michael; Jensen, Marlene Mark; Smets, Barth F.

    2018-01-01

    to an effective control of accumulation of nitrogen intermediates. However, due to frequent changes of redox conditions under intermittent aeration regimes, nitrous oxide production and emissions are dynamic. In this study the production and emission dynamics of nitrous oxide in an intermittently aerated......Emissions of the greenhouse gas nitrous oxide from the Partial Nitritation-Anammox process are of concern and can determine the carbon footprint of the process. In order to reduce nitrous oxide emissions intermittent aeration regimes have been shown to be a promising mode of operation, possibly due......-production rates were observed at ammonia removal rates below 5 mg NH3-N*gVSS−1*L−1, when the fraction of nitrous oxide produced was 0.011 ± 0.004% (per ammonia removed). Based on the nitrous oxide dynamics and correlations, reactor operation at relatively low nitrogen loadings (below 100 mg NH4+-N*L−1), ammonia...

  8. Incremental design of control system of SHARON-Anammox process for autotrophic nitrogen removal

    DEFF Research Database (Denmark)

    Mauricio Iglesias, Miguel; Valverde Perez, Borja; Sin, Gürkan

    2012-01-01

    With the perspective of investigating a suitable control design for autotrophic nitrogen removal, this work explores the control design for a SHARON-Anammox reactor sequence. With this aim, a full model is developed, including the pH dependency, in order to simulate the reactor and determine...

  9. Oxygen sensitivity of anammox and coupled N-cycle processes in oxygen minimum zones

    DEFF Research Database (Denmark)

    Kalvelage, Tim; Jensen, Marlene Mark; Contreras, Sergio

    2011-01-01

    on the global N-cycle. We examined the effect of oxygen (O2) on anammox, NH3 oxidation and NO3 2 reduction in 15N-labeling experiments with varying O2 concentrations (0–25 mmol L21) in the Namibian and Peruvian OMZs. Our results show that O2 is a major controlling factor for anammox activity in OMZ waters...... of ocean de-oxygenation on oceanic N-cycling.......Nutrient measurements indicate that 30–50% of the total nitrogen (N) loss in the ocean occurs in oxygen minimum zones (OMZs). This pelagic N-removal takes place within only ,0.1% of the ocean volume, hence moderate variations in the extent of OMZs due to global warming may have a large impact...

  10. Nitrogen Removal by Anammox Biofilm Column Reactor at Moderately Low Temperature

    Directory of Open Access Journals (Sweden)

    Tuty Emilia Agustina

    2017-10-01

    Full Text Available The anaerobic ammonium oxidation (anammox as a new biological approach for nitrogen removal has been considered to be more cost-effective compared with the combination of nitrification and denitrification process. However, the anammox bioreactors are mostly explored at high temperature (>300C in which temperature controlling system is fully required. This research was intended to develop and to apply anammox process for high nitrogen concentration removal at ambient temperature used for treating wastewater in tropical countries. An up-flow biofilm column reactor, which the upper part constructed with a porous polyester non-woven fabric material as a carrier to attach the anammox bacteria was operated without heating system. A maximum nitrogen removal rate (NRR of 1.05 kg-N m3 d-1 was reached in the operation days of 178 with a Total Nitrogen (TN removal efficiency of 74%. This showed the biofilm column anammox reactor was successfully applied to moderate high nitrogen removal from synthetic wastewater at moderately low temperature. Keywords: Anammox, biofilm column reactor, ambient temperature, nitrogen removal

  11. Implications of full-scale implementation of an anammox-based process as post-treatment of a municipal anaerobic sludge digester operated with co-digestion.

    Science.gov (United States)

    Vázquez-Padín, J R; Morales, N; Gutiérrez, R; Fernández, R; Rogalla, F; Barrio, J P; Campos, J L; Mosquera-Corral, A; Méndez, R

    2014-01-01

    The feasibility of treating the supernatant of a municipal sludge digester supplemented with co-substrates by means of an anammox-based process (ELAN(®)) was tested in Guillarei (NW of Spain). Ammonia concentration measured in the supernatant of the sludge digester varied in the range 800-1,500 g N/m(3) due to the fact that the sludge produced in the plant was co-digested with wastes coming from surrounding food industries. Treating this supernatant in the ELAN(®) reactor, nitrogen removal rates up to 1.1 kg N/(m(3) d) were reached in experiments run in a pilot plant reactor operated in batch mode. No nitrite oxidation was registered after several months of operation despite the average dissolved oxygen (DO) concentrations being 1.5 g O2/m(3) and the temperature reaching values as low as 18 °C. By keeping the DO set point at 1-2 g O2/m(3) and tuning the hydraulic retention time, the stability of the process was guaranteed and the presence of co-substrates in the anaerobic digester did not affect negatively the operation of the autotrophic nitrogen removal process. Due to the success of the pilot plant experiment, an upscale of the process to full scale is proposed. Mass balances applied to Guillarei wastewater treatment plant revealed that in the main stream line the average denitrification rate calculated with the data of year 2011 was 226 kg N/d. Since the nitrogen removal efficiency is limited by the amount of readily biodegradable organic matter available to carry out denitrification in the water line, the implementation of an anammox-based process to treat the supernatant seems the best option to improve the effluent quality in terms of nitrogen content. The nitrogen removal rate in the sludge line would be 30 times higher than the one in the water line. The implementation of the process would improve the energetic balance and the nitrogen removal performance of the plant.

  12. Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor

    International Nuclear Information System (INIS)

    Yang Zhiquan; Zhou Shaoqi; Sun Yanbo

    2009-01-01

    A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L -1 respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L -1 , respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic

  13. Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor.

    Science.gov (United States)

    Yang, Zhiquan; Zhou, Shaoqi; Sun, Yanbo

    2009-09-30

    A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L(-1) respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L(-1), respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic

  14. Long-term operation of oxygen-limiting membrane bioreactor (MBR) for the development of simultaneous partial nitrification, anammox and denitrification (SNAD) process.

    Science.gov (United States)

    Zhao, Chuanqi; Wang, Gang; Xu, Xiaochen; Yang, Yuesuo; Yang, Fenglin

    2017-07-18

    In this study, an oxygen-limiting membrane bioreactor (MBR) with recirculation of biogas for relieving membrane fouling was successfully operated to realize the simultaneous partial nitrification, anammox and denitrification (SNAD) process. The MBR operation was considered effective in the long-term test with total nitrogen (TN) and chemical oxygen demand (COD) removal efficiencies of 94.86% and 98.91%, respectively. Membrane fouling was significantly alleviated due to the recirculation of biogas and the membrane had been cleaned four times with a normal filtration period of 52 days. The co-existence of ammonia-oxidizing bacteria (AOB), anammox and denitrifying bacteria in MBR was confirmed by scanning electron microscopy (SEM) and fluorescence in situ hybridizations (FISH) analysis. Furthermore, AOB were found close to the granule surface, while denitrifying bacteria and anammox were in the deeper layer of granules. Potential in excellent TN and COD removal, operational stability and sustainability, as well as in alleviating membrane fouling is expected by using this oxygen-limiting MBR.

  15. NOx and ammonium isotopic fingerprints of anammox in natural and engineered systems: Implications for N isotope budgets and the use of NOx isotopes to diagnose process stability in wastewater treatment

    Science.gov (United States)

    Lehmann, M. F.; Stöcklin, N.; Brunner, B.; Frame, C. H.; Joss, A.; Kipf, M.; Kuhn, T.; Wunderlin, P.

    2014-12-01

    The anaerobic oxidation of ammonium with nitrite (anammox) has been identified as a very important fixed nitrogen (N) sink, accounting for a large fraction of global fixed N loss in marine, freshwater, and semi-terrestrial environments. In engineered systems, combined nitritation-anammox is an efficient process to remove N from ammonium-rich wastewater, with nitrite as the central intermediate. During the anammox process, nitrate is being produced, providing reducing equivalents for carbon fixation. Measuring the N isotope ratios in fixed N species (i.e., ammonium, nitrite, nitrate) has proven to be a valuable tool to track N cycling in freshwater and marine ecosystems, yet its application in wastewater treatment as a tool to diagnose nitrate production pathways is novel. In this presentation we will elucidate, and compare, the N isotope effects associated with anammox 1) in vitro, 2) in a lacustrine setting, and 3) in a small-scale batch reactor for wastewater treatment. We demonstrate that the anammox nitrite/nitrate isotopic signatures are modulated by the superposition of strong kinetic (normal and inverse) and equilibrium (nitrite-nitrate) N isotope fractionation. The ammonium N isotope effect is driven by kinetic N isotope fractionation, and is similar to that of nitrification. We will discuss the possible controls on the expression of the anammox N isotope effects in the natural environment. We will also evaluate the use of nitrate/nitrite N (and O) isotope signatures to distinguish between nitrate production by anammox versus nitrite oxidation, which is important for optimizing process efficiency during wastewater treatment.

  16. Short chain ladderanes: oxic biodegradation products of anammox lipids

    NARCIS (Netherlands)

    Rush, D.; Jaeschke, A.; Hopmans, E.C.; Geenevasen, J.A.J.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Anammox, the microbial anaerobic oxidation of ammonium by nitrite to produce dinitrogen gas, has been recognized as a key process in both the marine and freshwater nitrogen cycles, and found to be a major sink for fixed inorganic nitrogen in the oceans. Ladderane lipids are unique anammox bacterial

  17. Short chain ladderanes: Oxic biodegradation products of anammox lipids

    NARCIS (Netherlands)

    Rush, D.; Jaeschke, A.; Hopmans, E.C.; Geenevasen, J.A.J.; Schouten, S.; Sinninghe Damsté, J.S.

    2011-01-01

    Anammox, the microbial anaerobic oxidation of ammonium by nitrite to produce dinitrogen gas, has been recognized as a key process in both the marine and freshwater nitrogen cycles, and found to be a major sink for fixed inorganic nitrogen in the oceans. Ladderane lipids are unique anammox bacterial

  18. ANAMMOX-like performances for nitrogen removal from ammonium-sulfate-rich wastewater in an anaerobic sequencing batch reactor.

    Science.gov (United States)

    Prachakittikul, Pensiri; Wantawin, Chalermraj; Noophan, Pongsak Lek; Boonapatcharoen, Nimaradee

    2016-01-01

    Ammonium removal by the ANaerobic AMonium OXidation (ANAMMOX) process was observed through the Sulfate-Reducing Ammonium Oxidation (SRAO) process. The same concentration of ammonium (100 mg N L(-1)) was applied to two anaerobic sequencing batch reactors (AnSBRs) that were inoculated with the same activated sludge from the Vermicelli wastewater treatment process, while nitrite was fed in ANAMMOX and sulfate in SRAO reactors. In SRAO-AnSBR, in substrates that were fed with a ratio of NH4(+)/SO4(2-) at 1:0.4 ± 0.03, a hydraulic retention time (HRT) of 48 h and without sludge draining, the Ammonium Removal Rate (ARR) was 0.02 ± 0.01 kg N m(-3).d(-1). Adding specific ANAMMOX substrates to SRAO-AnSBR sludge in batch tests results in specific ammonium and nitrite removal rates of 0.198 and 0.139 g N g(-1) VSS.d, respectively, indicating that the ANAMMOX activity contributes to the removal of ammonium in the SRAO process using the nitrite that is produced from SRAO. Nevertheless, the inability of ANAMMOX to utilize sulfate to oxidize ammonium was also investigated in batch tests by augmenting enriched ANAMMOX culture in SRAO-AnSBR sludge and without nitrite supply. The time course of sulfate in a 24-hour cycle of SRAO-AnSBR showed an increase in sulfate after 6 h. For enriched SRAO culture, the uptake molar ratio of NH4(+)/SO4(2-) at 8 hours in a batch test was 1:0.82 lower than the value of 1:0.20 ± 0.09 as obtained in an SRAO-AnSBR effluent, while the stoichiometric ratio of 1:0.5 that includes the ANAMMOX reaction was in this range. After a longer operation of more than 2 years without sludge draining, the accumulation of sulfate and the reduction of ammonium removal were observed, probably due to the gradual increase in the sulfur denitrification rate and the competitive use of nitrite with ANAMMOX. The 16S rRNA gene PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and PCR cloning analyses resulted in the detection of the ANAMMOX

  19. Process stability and the recovery control associated with inhibition factors in a UASB-anammox reactor with a long-term operation.

    Science.gov (United States)

    Niu, Qigui; He, Shilong; Zhang, Yanlong; Ma, Haiyuan; Liu, Yuan; Li, Yu-You

    2016-03-01

    A UASB-anammox reactor was operated for 900 days to study its process stability. The negative effects of free ammonia (FA) and free nitrous acid (FNA) were investigated over three separate inhibitions and recoveries. The IC10, IC50 and IC90 (inhibitory concentration/a 10%, 50% and 90% activity loss) of FNA and FA responding to the NH4(+)-N, NO2(-)-N and TN removal efficiency were evaluated. In the 1st inhibition, the average FNA-IC10 observed was 0.67 μg L(-1) and the FA-IC10 for TN removal was 4.85 mg L(-1). In the 2nd inhibition, an FNA-IC10 of 0.44μ g L(-1) and an FA-IC10 of 3.56 were found. In the 3rd inhibition, however, both the FNA-IC10 and FA-IC10 were found to have increased, with values of 0.50 μg L(-1) and 4.42 mg L(-1), respectively. A clear control region was established for multiple inhibitions and the recoveries, which followed (pH 7.5-8.5, FA below 10mg/100mg NH4(+)-N and an FNA below 0.005 mg/100 mg NO2(-)-N) for the purpose of optimizing the operation conditions of the UASB-anammox reactor. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Microbial Community Composition and Ultrastructure of Granules from a Full-Scale Anammox Reactor

    KAUST Repository

    Gonzalez-Gil, Graciela

    2014-12-11

    Granules in anammox reactors contain besides anammox bacteria other microbial communities whose identity and relationship with the anammox bacteria are not well understood. High calcium concentrations are often supplied to anammox reactors to obtain sufficient bacterial aggregation and biomass retention. The aim of this study was to provide the first characterization of bacterial and archaeal communities in anammox granules from a full-scale anammox reactor and to explore on the possible role of calcium in such aggregates. High magnification imaging using backscattered electrons revealed that anammox bacteria may be embedded in calcium phosphate precipitates. Pyrosequencing of 16S rRNA gene fragments showed, besides anammox bacteria (Brocadiacea, 32 %), substantial numbers of heterotrophic bacteria Ignavibacteriacea (18 %) and Anaerolinea (7 %) along with heterotrophic denitrifiers Rhodocyclacea (9 %), Comamonadacea (3 %), and Shewanellacea (3 %) in the granules. It is hypothesized that these bacteria may form a network in which heterotrophic denitrifiers cooperate to achieve a well-functioning denitrification system as they can utilize the nitrate intrinsically produced by the anammox reaction. This network may provide a niche for the proliferation of archaea. Hydrogenotrophic methananogens, which scavenge the key fermentation product H2, were the most abundant archaea detected. Cells resembling the polygon-shaped denitrifying methanotroph Candidatus Methylomirabilis oxyfera were observed by electron microscopy. It is hypothesized that the anammox process in a full-scale reactor triggers various reactions overall leading to efficient denitrification and a sink of carbon as biomass in anammox granules.

  1. Startup and operating characteristics of an external air-lift reflux partial nitritation-ANAMMOX integrative reactor.

    Science.gov (United States)

    Li, Xiang; Huang, Yong; Yuan, Yi; Bi, Zhen; Liu, Xin

    2017-08-01

    The differences in the physiological characteristics between AOB and ANAMMOX bacteria lead to suboptimal performance when used in a single reactor. In this study, aerobic and anaerobic zones with different survival environments were constructed in a single reactor to realize partitioned culture of AOB and ANAMMOX bacteria. An external air-lift reflux system was formed which used the exhaust from the aeration zone as power to return the effluent to the aeration zone. The reflux system effectively alleviated the large pH fluctuations and promoted NO 2 - -N to rapidly use by ANAMMOX bacteria, effectively inhibiting the activity of NOB. After 95d of running, the nitrogen removal rate increased from the initial 0.21kg/(m 3 ·d) to 3.1kg/(m 3 ·d). FISH analyses further demonstrated that AOB and ANAMMOX bacteria acquired efficient enrichment in the corresponding zone. Thus, this type of integrative reactor may create the environments needed for the partial nitritation-ANAMMOX processing. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Interaction of anammox bacteria and inactive methanogenic granules under high nitrogen selective pressure.

    Science.gov (United States)

    Ni, Shou-Qing; Fessehaie, Anania; Lee, Po-Heng; Gao, Bao-Yu; Xu, Xing; Sung, Shihwu

    2010-09-01

    Granular anammox reactors usually adopted anaerobic/aerobic granules as source sludge, in which the washout of other species and enrichment of anammox biomass were very slow because of the competition of the coexisting bacteria. In this study, inactive methanogenic granules were proved to be suitable for rapid anammox granulation under high nitrogen concentrations by investigating their interaction with anammox bacteria. The start-up nitrite concentration was significantly higher than the published toxic level for anammox bacteria and other lab-scale studies. The nitrogen loading rate increased from 141 to 480 mg/L/d in 120 days operation with a total nitrogen removal efficiency of 96.0+/-0.6%. Anammox granules with a diameter of 1.3+/-0.4mm were observed over the course of three months. Molecular analysis showed that over 67% of the cells in the anammox granules were anammox bacteria after 90 days. The accommodations and proliferations of anammox bacteria in the inactive methanogenic granules might be the main reason for the high anammox purity in a short period. The important role of the extracellular polymer in the granule structure was observed via morphological observation. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Denitrification and Anammox in Tropical Aquaculture Settlement Ponds: An Isotope Tracer Approach for Evaluating N2 Production

    Science.gov (United States)

    Castine, Sarah A.; Erler, Dirk V.; Trott, Lindsay A.; Paul, Nicholas A.; de Nys, Rocky; Eyre, Bradley D.

    2012-01-01

    Settlement ponds are used to treat aquaculture discharge water by removing nutrients through physical (settling) and biological (microbial transformation) processes. Nutrient removal through settling has been quantified, however, the occurrence of, and potential for microbial nitrogen (N) removal is largely unknown in these systems. Therefore, isotope tracer techniques were used to measure potential rates of denitrification and anaerobic ammonium oxidation (anammox) in the sediment of settlement ponds in tropical aquaculture systems. Dinitrogen gas (N2) was produced in all ponds, although potential rates were low (0–7.07 nmol N cm−3 h−1) relative to other aquatic systems. Denitrification was the main driver of N2 production, with anammox only detected in two of the four ponds. No correlations were detected between the measured sediment variables (total organic carbon, total nitrogen, iron, manganese, sulphur and phosphorous) and denitrification or anammox. Furthermore, denitrification was not carbon limited as the addition of particulate organic matter (paired t-Test; P = 0.350, n = 3) or methanol (paired t-Test; P = 0.744, n = 3) did not stimulate production of N2. A simple mass balance model showed that only 2.5% of added fixed N was removed in the studied settlement ponds through the denitrification and anammox processes. It is recommended that settlement ponds be used in conjunction with additional technologies (i.e. constructed wetlands or biological reactors) to enhance N2 production and N removal from aquaculture wastewater. PMID:22962581

  4. Denitrification and anammox in tropical aquaculture settlement ponds: an isotope tracer approach for evaluating N2 production.

    Directory of Open Access Journals (Sweden)

    Sarah A Castine

    Full Text Available Settlement ponds are used to treat aquaculture discharge water by removing nutrients through physical (settling and biological (microbial transformation processes. Nutrient removal through settling has been quantified, however, the occurrence of, and potential for microbial nitrogen (N removal is largely unknown in these systems. Therefore, isotope tracer techniques were used to measure potential rates of denitrification and anaerobic ammonium oxidation (anammox in the sediment of settlement ponds in tropical aquaculture systems. Dinitrogen gas (N(2 was produced in all ponds, although potential rates were low (0-7.07 nmol N cm(-3 h(-1 relative to other aquatic systems. Denitrification was the main driver of N(2 production, with anammox only detected in two of the four ponds. No correlations were detected between the measured sediment variables (total organic carbon, total nitrogen, iron, manganese, sulphur and phosphorous and denitrification or anammox. Furthermore, denitrification was not carbon limited as the addition of particulate organic matter (paired t-Test; P = 0.350, n = 3 or methanol (paired t-Test; P = 0.744, n = 3 did not stimulate production of N(2. A simple mass balance model showed that only 2.5% of added fixed N was removed in the studied settlement ponds through the denitrification and anammox processes. It is recommended that settlement ponds be used in conjunction with additional technologies (i.e. constructed wetlands or biological reactors to enhance N(2 production and N removal from aquaculture wastewater.

  5. Metatranscriptomics reveals the molecular mechanism of large granule formation in granular anammox reactor

    KAUST Repository

    Bagchi, Samik

    2016-06-20

    Granules enriched with anammox bacteria are essential in enhancing the treatment of ammonia-rich wastewater, but little is known about how anammox bacteria grow and multiply inside granules. Here, we combined metatranscriptomics, quantitative PCR and 16S rRNA gene sequencing to study the changes in community composition, metabolic gene content and gene expression in a granular anammox reactor with the objective of understanding the molecular mechanism of anammox growth and multiplication that led to formation of large granules. Size distribution analysis revealed the spatial distribution of granules in which large granules having higher abundance of anammox bacteria (genus Brocadia) dominated the bottom biomass. Metatranscriptomics analysis detected all the essential transcripts for anammox metabolism. During the later stage of reactor operation, higher expression of ammonia and nitrite transport proteins and key metabolic enzymes mainly in the bottom large granules facilitated anammox bacteria activity. The high activity resulted in higher growth and multiplication of anammox bacteria and expanded the size of the granules. This conceptual model for large granule formation proposed here may assist in the future design of anammox processes for mainstream wastewater treatment.

  6. Mainstream partial nitritation-anammox in municipal wastewater treatment: status, bottlenecks, and further studies.

    Science.gov (United States)

    Cao, Yeshi; van Loosdrecht, Mark C M; Daigger, Glen T

    2017-02-01

    Driven by energy neutral/positive of wastewater treatment plants, significant efforts have been made on the research and development of mainstream partial nitritation and anaerobic ammonium oxidation (anammox) (PN/A) (deammonification) process since the early 2010s. To date, feasibility of mainstream PN/A process has been demonstrated and proven by experimental results at various scales although with the low loading rates and elevated nitrogen concentration in the effluent at low temperatures (15-10 °C). This review paper provides an overview of the current state of research and development of mainstream PN/A process and critically analyzes the bottlenecks for its full-scale application. The paper discusses the following: (i) the current status of research and development of mainstream PN/A process; (ii) the interactions among aerobic ammonium-oxidizing bacteria, aerobic nitrite-oxidizing bacteria, anammox bacteria, and heterotrophic bacteria; (iii) the suppression of aerobic nitrite-oxidizing bacteria; (iv) process and bioreactors; and (v) suggested further studies including efficient and robust carbon concentrating pretreatment, deepening of understanding competition between autotrophic nitrogen-converting organisms, intensification of biofilm anammox activity, reactor design, and final polishing.

  7. Isolation and characterization of a prokaryotic cell organelle from the anammox bacterium

    NARCIS (Netherlands)

    Neumann, S.; Wessels, H.J.C.T.; Rijpstra, W.I.C.; Sinninghe Damsté, J.S.; Kartal, B.; Jetten, M.S.M.; van Niftrik, L.

    2014-01-01

    Anaerobic ammonium oxidizing (anammox) bacteria oxidize ammonium with nitrite to nitrogen gas in the absence of oxygen. These microorganisms form a significant sink for fixed nitrogen in the oceans and the anammox process is applied as a cost-effective and environment-friendly nitrogen removal

  8. Roles of EDTA washing and Ca{sup 2+} regulation on the restoration of anammox granules inhibited by copper(II)

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zheng-Zhe; Cheng, Ya-Fei; Zhou, Yu-Huang; Buayi, Xiemuguli [Department of Environmental Science and Engineering, Hangzhou Normal University, Hangzhou 310036 (China); Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036 (China); Jin, Ren-Cun, E-mail: jrczju@aliyun.com [Department of Environmental Science and Engineering, Hangzhou Normal University, Hangzhou 310036 (China); Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036 (China)

    2016-01-15

    Highlights: • 80.5% of the Cu in anammox granules was introduced via adsorption. • Cu(II) internalized on/into AnAOB cells plays a crucial role in toxicity. • EDTA washing contributes to the detoxification of anammox granules. • Ca{sup 2+} can stimulate the re-growth of damaged anammox consortium. - Abstract: We investigated the feasibility of using ethylene diamine tetraacetic acid (EDTA) washing followed by Ca{sup 2+} enhancement for the recovery of anammox reactors inhibited by Cu(II). Kinetic experiments and batch activity assays were employed to determine the optimal concentration of EDTA and washing time; and the performance and physiological dynamics were tracked by continuous-flow monitoring to evaluate the long-term effects. The two-step desorption process revealed that the Cu in anammox granules was primarily introduced via adsorption (approximately, 80.5%), and the portion of Cu in the dispersible layer was predominant (accounting for 71.1%). Afterwards, the Cu internalized in the cells (approximately, 14.7%) could diffuse out of the cells and be gradually washed out of the reactor over the next 20 days. The Ca{sup 2+} addition that followed led to an accelerated nitrogen removal rate recovery slope (0.1491 kgN m{sup −3} d{sup −2}) and a normal biomass growth rate (0.054 d{sup −1}). The nitrogen removal rate returned to normal levels within 90 days and gradual improvements in granular characteristics were also achieved. Therefore, this study provides a new insight that externally removing the adsorbed heavy metals followed by internally repairing the metabolic system may represent an optimal restoration strategy for anammox consortium damaged by heavy metals.

  9. Unexpectedly high degree of anammox and DNRA in seagrass sediments: Description and application of a revised isotope pairing technique

    Science.gov (United States)

    Salk, Kateri R.; Erler, Dirk V.; Eyre, Bradley D.; Carlson-Perret, Natasha; Ostrom, Nathaniel E.

    2017-08-01

    Understanding the magnitude of nitrogen (N) loss and recycling pathways is crucial for coastal N management efforts. However, quantification of denitrification and anammox by a widely-used method, the isotope pairing technique, is challenged when dissimilatory NO3- reduction to NH4+ (DNRA) occurs. In this study, we describe a revised isotope pairing technique that accounts for the influence of DNRA on NO3- reduction (R-IPT-DNRA). The new calculation procedure improves on previous techniques by (1) accounting for N2O production, (2) distinguishing canonical anammox from coupled DNRA-anammox, and (3) including the production of 30N2 by anammox in the quantification of DNRA. This approach avoids the potential for substantial underestimates of anammox rates and overestimates of denitrification rates in systems where DNRA is a significant NO3- reduction pathway. We apply this technique to simultaneously quantify rates of anammox, denitrification, and DNRA in intact sediments adjacent to a seagrass bed in subtropical Australia. The effect of organic carbon lability on NO3- reduction was also addressed by adding detrital sources with differing C:N (phytoplankton- or seagrass-derived). DNRA was the predominant pathway, contributing 49-74% of total NO3- reduction (mean 0.42 μmol N m-2 h-1). In this high C:N system, DNRA outcompetes denitrification for NO3-, functioning to recycle rather than remove N. Anammox exceeded denitrification (mean 0.18 and 0.04 μmol N m-2 h-1, respectively) and accounted for 64-86% of N loss, a rare high percentage in shallow coastal environments. Owing to low denitrification activity, N2O production was ∼100-fold lower than in other coastal sediments (mean 7.7 nmol N m-2 h-1). All NO3- reduction pathways were stimulated by seagrass detritus but not by phytoplankton detritus, suggesting this microbial community is adapted to process organic matter that is typically encountered. The R-IPT-DNRA is widely applicable in other environments where the

  10. Modelling and control design for SHARON/Anammox reactor sequence

    DEFF Research Database (Denmark)

    Valverde Perez, Borja; Mauricio Iglesias, Miguel; Sin, Gürkan

    2012-01-01

    With the perspective of investigating a suitable control design for autotrophic nitrogen removal, this work presents a complete model of the SHARON/Anammox reactor sequence. The dynamics of the reactor were explored pointing out the different scales of the rates in the system: slow microbial...

  11. Anammox revisited: thermodynamic considerations in early studies of the microbial nitrogen cycle.

    Science.gov (United States)

    Oren, Aharon

    2015-08-01

    This paper explores the early literature on the thermodynamics of processes in the microbial nitrogen cycle, evaluating parameters of transfer of energy which depends on the initial and final states of the system, the mechanism of the reactions involved and the rates of these reactions. Processes discussed include the anaerobic oxidation of ammonium (the anammox reaction), the use of inorganic nitrogen compounds as electron donors for anoxygenic photosynthesis, and the mechanism and bioenergetics of biological nitrogen fixation. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Development of a fixed-bed anammox reactor with high treatment potential.

    Science.gov (United States)

    Okamoto, Hiroyuki; Kawamura, Kimito; Nishiyama, Takashi; Fujii, Takao; Furukawa, Kenji

    2013-02-01

    A plug-flow type anaerobic ammonium oxidation (anammox) reactor was developed using malt ceramics (MC) produced from carbonized spent grains as the biomass carriers for anammox sludge. Partial nitrified effluent of the filtrate from the sludge dehydrator of a brewery company was used as influent to a 20 L anammox reactor using MC. An average volumetric nitrogen removal rate (VNR) of 8.78 kg-N/m(3)/day was maintained stably for 76 days with 1 h of HRT. In a larger anammox reactor (400 L), an average VNR of 4.84 kg-N/m(3)/day could be maintained for 86 days during the treatment of low strength synthetic inorganic wastewater. As a result of bacterial community analysis for the 20 L anammox reactor, Asahi BRW1, probably originating from the wastewater collected at Asahi Breweries, was detected as the dominant anammox bacterium. These anammox reactors were characterized by a high NH(4)-N removal capacity for low strength wastewater with a short hydraulic retention time.

  13. Microbial Aggregate and Functional Community Distribution in a Sequencing Batch Reactor with Anammox Granules

    KAUST Repository

    Sun, Shan

    2013-05-01

    Anammox (anaerobic ammonium oxidation) process is a one-step conversion of ammonia into nitrogen gas with nitrite as an electron acceptor. It has been developed as a sustainable technology for ammonia removal from wastewater in the last decade. For wastewater treatment, anammox biomass was widely developed as microbial aggregate where the conditions for enrichment of anammox community must be delicately controlled and growth of other bacteria especially NOB should be suppressed to enhance nitrogen removal efficiency. Little is known about the distribution of microbial aggregates in anammox process. Thus the objective of our study was to assess whether segregation of biomass occurs in granular anammox system. In this study, a laboratory-scale sequential batch reactor (SBR) was successfully operated for a period of 80 days with granular anammox biomass. Temporal and spatial distribution of microbial aggregates was studied by particle characterization system and the distribution of functional microbial communities was studied with qPCR and 16s rRNA amplicon pyrosequencing. Our study revealed the spatial and temporal distribution of biomass aggregates based on their sizes and density. Granules (>200 μm) preferentially accumulated in the bottom of the reactor while floccules (30-200 μm) were relatively rich at the top layer. The average density of aggregate was higher at the bottom than the density of those at the top layer. Degranulation caused by lack of hydrodynamic shear force in the top layer was considered responsible for this phenomenon. NOB was relatively rich in the top layer while percentage of anammox population was higher at the bottom, and anammox bacteria population gradually increased over a period of time. NOB growth was supposed to be associated with the increase of floccules based on the concurrent occurrence. Thus, segregation of biomass can be utilized to develop an effective strategy to enrich anammox and wash out NOB by shortening the settling

  14. Abundance and diversity of denitrifying and anammox bacteria in seasonally hypoxic and sulfidic sediments of the saline lake grevelingen

    NARCIS (Netherlands)

    Lipsewers, Yvonne A.; Hopmans, Ellen C.; Meysman, Filip J.R.; Sinninghe Damsté, Jaap S.; Villanueva, Laura

    2016-01-01

    Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity, and potential activity of denitrifying, anammox,

  15. Abundance and Diversity of Denitrifying and Anammox Bacteria in Seasonally Hypoxic and Sulfidic Sediments of the Saline Lake Grevelingen

    NARCIS (Netherlands)

    Lipsewers, Y.A.; Hopmans, E.C.; Meysman, F.J.R.; Sinninghe Damsté, J.S.; Villanueva, L.

    2016-01-01

    Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity, and potential activity of denitrifying, anammox,

  16. Inactivation of ANAMMOX communities under concurrent operation of anaerobic ammonium oxidation (ANAMMOX) and denitrification

    DEFF Research Database (Denmark)

    Chamchoi, N.; Nitisoravut, S.; Schmidt, Jens Ejbye

    2008-01-01

    A concurrent operation of anaerobic ammonium oxidation (ANAMMOX) and denitrification was investigated in a well known UASB reactor seeding with both ANAMMOX and anaerobic granular sludges. ANAMMOX activity was confirmed by hydroxylamine test and the hybridization of biomass using the gene probes...

  17. Anaerobic ammonium oxidation by anammox bacteria in the Black Sea

    Science.gov (United States)

    Kuypers, Marcel M. M.; Sliekers, A. Olav; Lavik, Gaute; Schmid, Markus; Jørgensen, Bo Barker; Kuenen, J. Gijs; Sinninghe Damsté, Jaap S.; Strous, Marc; Jetten, Mike S. M.

    2003-04-01

    The availability of fixed inorganic nitrogen (nitrate, nitrite and ammonium) limits primary productivity in many oceanic regions. The conversion of nitrate to N2 by heterotrophic bacteria (denitrification) is believed to be the only important sink for fixed inorganic nitrogen in the ocean. Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N2 in the world's largest anoxic basin, the Black Sea. Phylogenetic analysis of 16S ribosomal RNA gene sequences shows that these bacteria are related to members of the order Planctomycetales performing the anammox (anaerobic ammonium oxidation) process in ammonium-removing bioreactors. Nutrient profiles, fluorescently labelled RNA probes, 15N tracer experiments and the distribution of specific `ladderane' membrane lipids indicate that ammonium diffusing upwards from the anoxic deep water is consumed by anammox bacteria below the oxic zone. This is the first time that anammox bacteria have been identified and directly linked to the removal of fixed inorganic nitrogen in the environment. The widespread occurrence of ammonium consumption in suboxic marine settings indicates that anammox might be important in the oceanic nitrogen cycle.

  18. Denitrification synergized with ANAMMOX for the anaerobic degradation of benzene: performance and microbial community structure.

    Science.gov (United States)

    Peng, Shuchan; Zhang, Lilan; Zhang, DaiJun; Lu, Peili; Zhang, Xiaoting; He, Qiang

    2017-05-01

    To evaluate the effect of anaerobic ammonium oxidation (ANAMMOX) on benzene degradation under denitrification, a sequencing batch reactor (SBR) under denitrification synergized with ANAMMOX (SBR-DenAna) for benzene degradation was established by inoculating anaerobic ammonium-oxidizing bacteria (AnAOB) into a SBR under denitrification reactor (SBR-Den) for benzene degradation. The average rate of benzene degradation and the maximum first-order kinetic constant in SBR-DenAna were 2.34- and 1.41-fold those in SBR-Den, respectively, indicating that ANAMMOX improved the degradation of benzene under denitrification synergized with ANAMMOX. However, the average rate of benzene degradation decreased by 35% in the denitrification-ANAMMOX synergistic reactor when 10 mg N L -1 NO 2 - was added; the rate recovered once NO 2 - was depleted, indicating that ANAMMOX might detoxify NO 2 - . Results from high-throughput sequencing analysis revealed that Azoarcus within the family Rhodocyclaceae might be associated with benzene degradation in the two SBRs. AnAOB affiliated with the family Candidatus Brocadiaceae were just detected in SBR-DenAna.

  19. Influencing factors analysis of anammox bacteria cultured by mixing denitrifying-anammox

    OpenAIRE

    Sihui WANG; Yuanyuan SONG; Yunman LIU; Yankai GUO; Jing LIAN; Jianbo GUO

    2017-01-01

    In order to get the optimal growth conditions of anammox bacteria, the mature-cultured anammox granule sludge is used to investigate the influencing factors. The effects of temperature, pH value, COD and influent substrate (NO-2-N and NH+4-N) on anammox bacteria activity are investigated. The results demonstrate that the optimal temperature is 40 ℃ and the optimal pH value is between 7.0~8.0 for anammox bacteria. The anammox bacteria activity is not inhibited severely when COD concentration i...

  20. Advances in methods for detection of anaerobic ammonium oxidizing (anammox) bacteria

    OpenAIRE

    Li, Meng; Gu, Ji-Dong

    2011-01-01

    Anaerobic ammonium oxidation (anammox), the biochemical process oxidizing ammonium into dinitrogen gas using nitrite as an electron acceptor, has only been recognized for its significant role in the global nitrogen cycle not long ago, and its ubiquitous distribution in a wide range of environments has changed our knowledge about the contributors to the global nitrogen cycle. Currently, several groups of methods are used in detection of anammox bacteria based on their physiological and biochem...

  1. Anaerobic ammonium oxidation by anammox bacteria in the Black Sea RID B-8834-2011

    DEFF Research Database (Denmark)

    Kuypers, MMM; Sliekers, AO; Lavik, G.

    2003-01-01

    ). Here we provide evidence for bacteria that anaerobically oxidize ammonium with nitrite to N(2) in the world's largest anoxic basin, the Black Sea. Phylogenetic analysis of 16S ribosomal RNA gene sequences shows that these bacteria are related to members of the order Planctomycetales performing...... the anammox (anaerobic ammonium oxidation) process in ammonium-removing bioreactors(3). Nutrient profiles, fluorescently labelled RNA probes, (15)N tracer experiments and the distribution of specific 'ladderane' membrane lipids(4) indicate that ammonium diffusing upwards from the anoxic deep water is consumed...... by anammox bacteria below the oxic zone. This is the first time that anammox bacteria have been identified and directly linked to the removal of fixed inorganic nitrogen in the environment. The widespread occurrence of ammonium consumption in suboxic marine settings(5-7) indicates that anammox might...

  2. A microdiversity study of anammox bacteria reveals a novel Candidatus Scalindua phylotype in marine oxygen minimum zones.

    Science.gov (United States)

    Woebken, Dagmar; Lam, Phyllis; Kuypers, Marcel M M; Naqvi, S Wajih A; Kartal, Boran; Strous, Marc; Jetten, Mike S M; Fuchs, Bernhard M; Amann, Rudolf

    2008-11-01

    The anaerobic oxidation of ammonium (anammox) contributes significantly to the global loss of fixed nitrogen and is carried out by a deep branching monophyletic group of bacteria within the phylum Planctomycetes. Various studies have implicated anammox to be the most important process responsible for the nitrogen loss in the marine oxygen minimum zones (OMZs) with a low diversity of marine anammox bacteria. This comprehensive study investigated the anammox bacteria in the suboxic zone of the Black Sea and in three major OMZs (off Namibia, Peru and in the Arabian Sea). The diversity and population composition of anammox bacteria were investigated by both, the 16S rRNA gene sequences and the 16S-23S rRNA internal transcribed spacer (ITS). Our results showed that the anammox bacterial sequences of the investigated samples were all closely related to the Candidatus Scalindua genus. However, a greater microdiversity of marine anammox bacteria than previously assumed was observed. Both phylogenetic markers supported the classification of all sequences in two distinct anammox bacterial phylotypes: Candidatus Scalindua clades 1 and 2. Scalindua 1 could be further divided into four distinct clusters, all comprised of sequences from either the Namibian or the Peruvian OMZ. Scalindua 2 consisted of sequences from the Arabian Sea and the Peruvian OMZ and included one previously published 16S rRNA gene sequence from Lake Tanganyika and one from South China Sea sediment (97.9-99.4% sequence identity). This cluster showed only anammox bacteria of Scalindua clade 2 represent a novel anammox bacterial species, for which the name Candidatus Scalindua arabica is proposed. As sequences of this new cluster were found in the Arabian Sea, the Peruvian OMZ, in Lake Tanganyika and in South China sediment, we assume a global distribution of Candidatus Scalindua arabica as it is observed for Candidatus Scalindua sorokinii/brodae (or Scalindua clade 1).

  3. Successful application of nitritation/anammox to wastewater with elevated organic carbon to ammonia ratios.

    Science.gov (United States)

    Jenni, Sarina; Vlaeminck, Siegfried E; Morgenroth, Eberhard; Udert, Kai M

    2014-02-01

    The nitritation/anammox process has been mainly applied to high-strength nitrogenous wastewaters with very low biodegradable organic carbon content (wastewaters have biodegradable organic carbon to nitrogen (COD/N) ratios between 0.5 and 1.7 g COD∙g N(-1) and thus, contain elevated amounts of organic carbon but not enough for heterotrophic denitrification. In this study, the influence of elevated COD/N ratios was studied on a nitritation/anammox process with suspended sludge. In a step-wise manner, the influent COD/N ratio was increased to 1.4 g COD∙g N(-1) by supplementing digester supernatant with acetate. The increasing availability of COD led to an increase of the nitrogen removal efficiency from around 85% with pure digester supernatant to >95% with added acetate while the nitrogen elimination rate stayed constant (275 ± 40 mg N∙L(-1)∙d(-1)). Anammox activity and abundance of anammox bacteria (AMX) were strongly correlated, and with increasing influent COD/N ratio both decreased steadily. At the same time, heterotrophic denitrification with nitrite and the activity of ammonia oxidising bacteria (AOB) gradually increased. Simultaneously, the sludge retention time (SRT) decreased significantly with increasing COD loading to about 15 d and reached critical values for the slowly growing AMX. When the SRT was increased by reducing biomass loss with the effluent, AMX activity and abundance started to rise again, while the AOB activity remained unaltered. Fluorescent in-situ hybridisation (FISH) showed that the initial AMX community shifted within only 40 d from a mixed AMX community to "Candidatus Brocadia fulgida" as the dominant AMX type with an influent COD/N ratio of 0.8 g COD∙g N(-1) and higher. "Ca. Brocadia fulgida" is known to oxidise acetate, and its ability to outcompete other types of AMX indicates that AMX participated in acetate oxidation. In a later phase, glucose was added to the influent instead of acetate. The new substrate

  4. Rate independent Kurzweil processes

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel; Liero, M.

    2009-01-01

    Roč. 54, č. 2 (2009), s. 117-145 ISSN 0862-7940 Institutional research plan: CEZ:AV0Z10190503 Keywords : Kurzweil integral * rate independence Subject RIV: BA - General Mathematics Impact factor: 0.410, year: 2009 http://www.dml.cz/bitstream/handle/10338.dmlcz/140355/AplMat_54-2009-2_2.pdf

  5. Molecular detection of Candidatus Scalindua pacifica and environmental responses of sediment anammox bacterial community in the Bohai Sea, China.

    Directory of Open Access Journals (Sweden)

    Hongyue Dang

    Full Text Available The Bohai Sea is a large semi-enclosed shallow water basin, which receives extensive river discharges of various terrestrial and anthropogenic materials such as sediments, nutrients and contaminants. How these terrigenous inputs may influence the diversity, community structure, biogeographical distribution, abundance and ecophysiology of the sediment anaerobic ammonium oxidation (anammox bacteria was unknown. To answer this question, an investigation employing both 16S rRNA and hzo gene biomarkers was carried out. Ca. Scalindua bacteria were predominant in the surface sediments of the Bohai Sea, while non-Scalindua anammox bacteria were also detected in the Yellow River estuary and inner part of Liaodong Bay that received strong riverine and anthropogenic impacts. A novel 16S rRNA gene sequence clade was identified, putatively representing an anammox bacterial new candidate species tentatively named "Ca. Scalindua pacifica". Several groups of environmental factors, usually with distinct physicochemical or biogeochemical natures, including general marine and estuarine physicochemical properties, availability of anammox substrates (inorganic N compounds, alternative reductants and oxidants, environmental variations caused by river discharges and associated contaminants such as heavy metals, were identified to likely play important roles in influencing the ecology and biogeochemical functioning of the sediment anammox bacteria. In addition to inorganic N compounds that might play a key role in shaping the anammox microbiota, organic carbon, organic nitrogen, sulfate, sulfide and metals all showed the potentials to participate in the anammox process, releasing the strict dependence of the anammox bacteria upon the direct availability of inorganic N nutrients that might be limiting in certain areas of the Bohai Sea. The importance of inorganic N nutrients and certain other environmental factors to the sediment anammox microbiota suggests that these

  6. Molecular Detection of Candidatus Scalindua pacifica and Environmental Responses of Sediment Anammox Bacterial Community in the Bohai Sea, China

    Science.gov (United States)

    Dang, Hongyue; Zhou, Haixia; Zhang, Zhinan; Yu, Zishan; Hua, Er; Liu, Xiaoshou; Jiao, Nianzhi

    2013-01-01

    The Bohai Sea is a large semi-enclosed shallow water basin, which receives extensive river discharges of various terrestrial and anthropogenic materials such as sediments, nutrients and contaminants. How these terrigenous inputs may influence the diversity, community structure, biogeographical distribution, abundance and ecophysiology of the sediment anaerobic ammonium oxidation (anammox) bacteria was unknown. To answer this question, an investigation employing both 16S rRNA and hzo gene biomarkers was carried out. Ca. Scalindua bacteria were predominant in the surface sediments of the Bohai Sea, while non-Scalindua anammox bacteria were also detected in the Yellow River estuary and inner part of Liaodong Bay that received strong riverine and anthropogenic impacts. A novel 16S rRNA gene sequence clade was identified, putatively representing an anammox bacterial new candidate species tentatively named “Ca. Scalindua pacifica”. Several groups of environmental factors, usually with distinct physicochemical or biogeochemical natures, including general marine and estuarine physicochemical properties, availability of anammox substrates (inorganic N compounds), alternative reductants and oxidants, environmental variations caused by river discharges and associated contaminants such as heavy metals, were identified to likely play important roles in influencing the ecology and biogeochemical functioning of the sediment anammox bacteria. In addition to inorganic N compounds that might play a key role in shaping the anammox microbiota, organic carbon, organic nitrogen, sulfate, sulfide and metals all showed the potentials to participate in the anammox process, releasing the strict dependence of the anammox bacteria upon the direct availability of inorganic N nutrients that might be limiting in certain areas of the Bohai Sea. The importance of inorganic N nutrients and certain other environmental factors to the sediment anammox microbiota suggests that these bacteria were

  7. Concurrent activity of anammox and denitrifying bacteria in the Black Sea.

    Science.gov (United States)

    Kirkpatrick, John B; Fuchsman, Clara A; Yakushev, Evgeniy; Staley, James T; Murray, James W

    2012-01-01

    After the discovery of ANaerobic AMMonium OXidation (anammox) in the environment, the role of heterotrophic denitrification as the main marine pathway for fixed N loss has been questioned. A 3 part, 15 month time series investigating nitrite reductase (nirS) mRNA transcripts at a single location in the Black Sea was conducted in order to better understand the activity of anammox and denitrifying bacteria. Here we show that both of these groups were active, as well as being concurrent in the lower suboxic zone over this time span. Their distributions, however, differed in that only expression of denitrification-type nirS was seen in the upper suboxic zone, where geochemistry was variable. Depth profiles covering the suboxic zone showed that the four groups of anammox-type sequences were expressed consistently in the lower suboxic zone, and were consistent with anammox 16 S rDNA gene profiles. By contrast, denitrifier-type nirS sequence groups were mixed; some groups exhibited consistent expression in the lower suboxic zone, while others appeared less consistent. Co-occurrence of both anammox and denitrifier expression was common and ongoing. Both types of transcripts were also found in samples with low concentrations of sulfide (>2 μM). Six major groups of denitrifier-type nirS transcripts were identified, and several groups of denitrifier-type nirS transcripts were closely related to sequences from the Baltic Sea. An increase in denitrifier-type nirS transcript diversity and depth range in October 2007 corresponded to a small increase in mixed layer net community productivity (NCP) as measured by O(2)/Ar gas ratios, as well as to an increase in N(2) concentrations in the suboxic zone. Taken together, the variations in expression patterns between anammox and denitrification provide one possible explanation as to how near instantaneous rate measurements, such as isotope spike experiments, may regularly detect anammox activity but underreport denitrification.

  8. Concurrent Activity of Anammox and Denitrifying Bacteria in the Black Sea

    Directory of Open Access Journals (Sweden)

    John B. Kirkpatrick

    2012-07-01

    Full Text Available After the discovery of ANaerobic AMMonium OXidation (anammox in the Black Sea in 2003, the role of heterotrophic denitrification as the main marine pathway for fixed N loss was questioned. A 3 part, 15 month time series investigating Black Sea nitrite reductase (nirS mRNA transcripts at a single location was conducted in order to better understand the activity of anammox and denitrifying bacteria. Here we show that both of these groups were active, as well as being concurrent in the lower suboxic zone over this time span. Their distributions, however, were fundamentally different; denitrification expression was much more variable. Depth profiles covering the suboxic zone showed that the four groups of anammox-type sequences were expressed consistently in the lower suboxic zone, and were consistent with anammox 16S rDNA gene profiles. By contrast, denitrifier-type nirS sequence groups were mixed; half of the groups exhibited consistent expression in the lower suboxic zone, while others varied between season and depth. Co-occurrence of both anammox and denitrifier expression was common and ongoing. Both types of transcripts were also found in samples with low concentrations of sulfide ( >2 μM. 6 major groups of denitrifier-type nirS transcripts were identified, making these transcripts more diverse than previous DNA clone libraries. Several groups of denitrifier-type nirS transcripts were closely related to sequences from the Baltic Sea. An increase in denitrifier-type nirS transcript diversity and depth range in October 2007 corresponded to an increase in mixed layer net community productivity as measured by O2/Ar gas ratios, as well as to an increase in N2 concentrations in the upper suboxic zone. Taken together, the variations in expression patterns between anammox and denitrification provide one explanation as to how near instantaneous rate measurements, such as isotope spike experiments, may regularly detect anammox activity but underreport

  9. The anammoxosome : An intracytoplasmic compartment in anammox bacteria

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Niftrik, L.A. van; Fuerst, J.A.; Kuenen, J.G.; Jetten, M.S.M.; Strous, M.

    2004-01-01

    Anammox bacteria belong to the phylum Planctomycetes and perform anaerobic ammonium oxidation (anammox); they oxidize ammonium with nitrite as the electron acceptor to yield dinitrogen gas. The anammox reaction takes place inside the anammoxosome: an intracytoplasmic compartment bounded by a single

  10. The anammoxosome: an intracytoplasmic compartment in anammox bacteria

    NARCIS (Netherlands)

    Niftrik, L.A.M.P. van; Fuerst, J.A.; Damste, J.S.S.; Kuenen, J.G.; Jetten, M.S.M.; Strous, M.

    2004-01-01

    Anammox bacteria belong to the phylum Planctomycetes and perform anaerobic ammonium oxidation (anammox); they oxidize ammonium with nitrite as the electron acceptor to yield dinitrogen gas. The anammox reaction takes place inside the anammoxosome: an intracytoplasmic compartment bounded by a single

  11. Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Mutlu, A. Gizem; Jensen, Marlene Mark

    2014-01-01

    Autotrophic nitrogen removal is regarded as a resource efficient process to manage nitrogen-rich residual streams. However, nitrous oxide emissions of these processes are poorly documented and strategies to mitigate emissions unknown. In this study, two sequencing batch reactors performing single......-stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75g-N/L.d) and high nitrogen removal efficiencies (83 +/- 5 and 88 +/- 2%) obtained. Dynamics of liquid phase nitrous (N2O......) and nitric oxide (NO) concentrations were monitored and N2O emissions calculated. Significant decreases in N2O emissions were obtained when the frequency of aeration was increased while maintaining a constant air flow rate (from >6 to 1.7% Delta N2O/Delta TN). However, no significant effect on the emissions...

  12. Rapid startup and high rate nitrogen removal from anaerobic sludge digester liquor using a SNAP process.

    Science.gov (United States)

    Qiao, Sen; Nishiyama, Takashi; Fujii, Tatsuo; Bhatti, Zafar; Furukawa, Kenji

    2012-02-01

    In this study, a single-stage autotrophic nitrogen removal reactor, packed with a novel acrylic fiber biomass carrier material (Biofix), was applied for nitrogen removal from sludge digester liquor. For rapid start-up, conventional activated sludge was added to the reactor soon after the attachment of anammox biomass on the Biofix carriers, which allowed conventional activated sludge to form a protective layer of biofilm around the anammox biomass. The Nitrogen removal efficiency reached 75% within 1 week at a nitrogen loading rate of 0.46 kg-N/m(3)/day for synthetic wastewater treatment. By the end of the synthetic wastewater treatment period, the maximum nitrogen removal rate had increased to 0.92 kg-N/m(3)/day at a nitrogen loading rate of 1.0 kg-N/m(3)/day. High nitrogen removal rate was also achieved during the actual raw digester liquor treatment with the highest nitrogen removal rate being 0.83 kg-N/m(3)/day at a nitrogen loading rate of 0.93 kg-N/m(3)/day. The thick biofilm on Biofix carriers allowed anammox bacteria to survive under high DO concentration of 5-6 mg/l resulting in stable and high nitrogen removal performance. FISH and CLSM analysis demonstrated that anammox bacteria coexisted and surrounded by ammonium oxidizing bacteria.

  13. Source identification of nitrous oxide emission pathways from a single-stage nitritation-anammox granular reactor

    KAUST Repository

    Ali, Muhammad

    2016-06-16

    Nitrous oxide (N2O) production pathway in a signal-stage nitritation-anammox sequencing batch reactor (SBR) was investigated based on a multilateral approach including real-time N2O monitoring, N2O isotopic composition analysis, and in-situ analyses of spatial distribution of N2O production rate and microbial populations in granular biomass. N2O emission rate was high in the initial phase of the operation cycle and gradually decreased with decreasing NH4+ concentration. The average emission of N2O was 0.98 ± 0.42% and 1.35 ± 0.72% of the incoming nitrogen load and removed nitrogen, respectively. The N2O isotopic composition analysis revealed that N2O was produced via NH2OH oxidation and NO2− reduction pathways equally, although there is an unknown influence from N2O reduction and/or anammox N2O production. However, the N2O isotopomer analysis could not discriminate the relative contribution of nitrifier denitrification and heterotrophic denitrification in the NO2− reduction pathway. Various in-situ techniques (e.g. microsensor measurements and FISH (fluorescent in-situ hybridization) analysis) were therefore applied to further identify N2O producers. Microsensor measurements revealed that approximately 70% of N2O was produced in the oxic surface zone, where nitrifiers were predominantly localized. Thus, NH2OH oxidation and NO2 reduction by nitrifiers (nitrifier-denitrification) could be responsible for the N2O production in the oxic zone. The rest of N2O (ca. 30%) was produced in the anammox bacteria-dominated anoxic zone, probably suggesting that NO2− reduction by coexisting putative heterotrophic denitrifiers and some other unknown pathway(s) including the possibility of anammox process account for the anaerobic N2O production. Further study is required to identify the anaerobic N2O production pathways. Our multilateral approach can be useful to quantitatively examine the relative contributions of N2O production pathways. Good understanding of the key N2O

  14. Enrichment of anammox bacteria from three sludge sources for the startup of monosodium glutamate industrial wastewater treatment system.

    Science.gov (United States)

    Li-dong, Shen; An-hui, Hu; Ren-cun, Jin; Dong-qing, Cheng; Ping, Zheng; Xiang-yang, Xu; Bao-lan, Hu

    2012-01-15

    Three activated sludges from a landfill leachate treatment plant (S1), a municipal sewage treatment plant (S2) and a monosodium glutamate (MSG) wastewater treatment plant (S3) were used as inocula to enrich anaerobic ammonium oxidation (anammox) bacteria for the startup of MSG industrial wastewater treatment system. After 360 days of cultivation using MSG wastewater, obvious anammox activity was observed in all three cultures. The maximum specific anammox activities of cultures S1, S2 and S3 were 0.11 kg N kg(-1) VSS day(-1), 0.09 kg N kg(-1) VSS day(-1) and 0.16 kg N kg(-1) VSS day(-1), respectively. Brownish-red anammox granules having diameters in the range of 0.2-1.0mm were visible in cultures S1 and S2, and large red granules having diameters in the range of 0.5-2.5mm were formed in culture S3 after 420 days of cultivation. Phylogenetic analysis of 16S rRNA genes showed that Kuenenia organisms were the dominant anammox species in all three cultures. The copy numbers of 16S rRNA genes of anammox bacteria in cultures S1, S2 and S3 were 6.8 × 10(7) copies mL(-1), 9.4 × 10(7) copies mL(-1) and 7.5 × 10(8) copies mL(-1), respectively. The results of this study demonstrated that anammox cultivation from conventional activated sludges was highly possible using MSG wastewater. Thus the anammox process has possibility of applying to the nitrogen removal from MSG wastewater. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Biogeography of anaerobic ammonia-oxidizing (anammox bacteria

    Directory of Open Access Journals (Sweden)

    Puntipar eSonthiphand

    2014-08-01

    Full Text Available Anaerobic ammonia-oxidizing (anammox bacteria are able to oxidize ammonia and reduce nitrite to produce N2 gas. After being discovered in a wastewater treatment plant (WWTP, anammox bacteria were subsequently characterized in natural environments, including marine, estuary, freshwater, and terrestrial habitats. Anammox bacteria play an important role in removing fixed N from both engineered and natural ecosystems, but broad scale anammox bacterial distributions, based on available data, have not yet been summarized. The objectives of this study were to explore global distributions and diversity of anammox bacteria and to identify factors that influence their biogeography. Over 6,000 anammox 16S rRNA gene sequences from the public database were analyzed in this current study. Data ordinations indicated that salinity was an important factor governing anammox bacterial distributions, with distinct populations inhabiting natural and engineered ecosystems. Gene phylogenies and rarefaction analysis demonstrated that freshwater environments and the marine water column harbored the highest and the lowest diversity of anammox bacteria, respectively. A co-occurrence network analysis indicated that Ca. Scalindua strongly correlated with other Ca. Scalindua taxa, whereas Ca. Brocadia co-occurred with taxa from both known and unknown anammox genera. Our survey provides a better understanding of ecological factors affecting anammox bacterial distributions and provides a comprehensive baseline for understanding the relationships among anammox communities in global environments.

  16. Microbial competition among anammox bacteria in nitrite-limited bioreactors

    KAUST Repository

    Zhang, Lei

    2017-08-26

    Phylogenetically diverse anammox bacteria have been detected in most of anoxic natural and engineered ecosystems and thus regarded as key players in the global nitrogen cycle. However, ecological niche differentiation of anammox bacteria remains unresolved despite its ecological and practical importance. In this study, the microbial competitions for a common substrate (nitrite) among three anammox species (i.e. “Candidatus Brocadia sinica”, “Candidatus Jettenia caeni” and “Candidatus Kuenenia stuttgartiensis”) were systematically investigated in nitrite-limited gel-immobilized column reactors (GICR) and membrane bioreactors (MBRs) under different nitrogen loading rates (NLRs). 16 S rRNA gene-based population dynamics revealed that “Ca. J. caeni” could proliferate only at low NLRs, whereas “Ca. B. sinica” outcompeted other two species at higher NLRs in both types of reactors. Furthermore, FISH analysis revealed that “Ca. J. caeni” was mainly present as spherical microclusters at the inner part (low NO2− environment), whereas “Ca. B. sinica” was present throughout the gel beads and granules. This spatial distribution supports the outcomes of the competition experiments. However, the successful competition of “Ca. J. caeni” at low NLR could not be explained with the Monod model probably due to inaccuracy of kinetic parameters such as half saturation constant (Ks) for nitrite and a difference in the maintenance rate (m). In addition, the growth of “Ca. K. stuttgartiensis” could not be observed in any experimental conditions, suggesting possible unknown factor(s) is missing. Taken together, NLR was one of factors determining ecological niche differentiation of “Ca. B. sinica” and “Ca. J. caeni”.

  17. Stoichiometric variation and loading capacity of a high-loading anammox attached film expanded bed (AAEEB) reactor.

    Science.gov (United States)

    Zhang, Yanlong; Ma, Haiyuan; Chen, Rong; Niu, Qigui; Li, Yu-You

    2018-04-01

    The nitrogen loading rate (NLR) of an anammox attached film expanded bed (AAFEB) reactor was increased from 5.0 to 60.0 gN/L/d. During the stable operational period, the TN removal efficiency maintained at 87.3 ± 2.5%, and a maximum nitrogen removal rate (NRR) of 44.9 ± 0.3 gN/L/d was achieved. Overload resulted in the sharp deterioration of reactor performance, the ratio of (Food/Microorganism)/SAA should be maintained at lower than 66 ± 7% to ensure the stable operation of the AAFEB reactor. New stoichiometric equations for the anammox process under the low NLR condition (5.0 gN/L/d) and the high NLR condition (50.0 gN/L/d) were proposed. The quantitative SAA-cytochrome heme C relationship was established for the first time that providing a simple way for monitoring the reactor performance. Substrate tolerance ability was significantly increased that proving the stability of the AAFEB reactor was continuously enhanced during the stable operational periods. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Startup of a Partial Nitritation-Anammox MBBR and the Implementation of pH-Based Aeration Control.

    Science.gov (United States)

    Klaus, Stephanie; Baumler, Rick; Rutherford, Bob; Thesing, Glenn; Zhao, Hong; Bott, Charles

    2017-06-01

      The single-stage deammonification moving bed biofilm reactor (MBBR) is a process for treating high strength nitrogen waste streams. In this process, partial nitritation and anaerobic ammonia oxidation (anammox) occur simultaneously within a biofilm attached to plastic carriers. An existing tank at the James River Treatment Plant (76 ML/d) in Newport News, Virginia was modified to install a sidestream deammonification MBBR process. This was the second sidestream deammonification process in North America and the first MBBR type installation. After 4 months the process achieved greater than 85% ammonia removal at the design loading rate of 2.4 g /m2·d (256 kg /d) signaling the end of startup. Based on observations during startup and process optimization phases, a novel pH-based control system was developed that maximizes ammonium removal and results in stable aeration and effluent alkalinity.

  19. Enrichment and biofilm formation of Anammox bacteria in a non-woven membrane reactor.

    Science.gov (United States)

    Ni, Shou-Qing; Lee, Po-Heng; Fessehaie, Anania; Gao, Bao-Yu; Sung, Shihwu

    2010-03-01

    An innovative reactor configuration for Anammox enrichment by connecting a non-woven membrane module with an anaerobic reactor was developed in this study. The Anammox non-woven membrane reactor (ANMR) exhibited high biomass retention ability through the formation of aggregates in the reactor and biofilm on the interior surface of the non-woven membrane. No fouling problems occurred on the membrane after the development of mature biofilms. After 8 months of operation, the nitrogen loading rate (NLR) and nitrogen removal rate (NRR) reached 1263 mg N/l/d and 1047.5 mg N/l/d, respectively, with a maximum specific ammonium consumption (SAC) of 51 nmol/mg protein/min. At steady state, the average ammonium and nitrite removal efficiencies were 90.9% and 95.0%, respectively. Morphological observation of Anammox aggregates and biofilm showed a high degree of compactness. Also, enrichment of Anammox bacteria was quantified by real-time polymerase chain reaction (PCR) analysis as 97.7%. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  20. Effect of organic matter strength on anammox for modified greenhouse turtle breeding wastewater treatment.

    Science.gov (United States)

    Chen, Chongjun; Huang, Xiaoxiao; Lei, Chenxiao; Zhang, Tian C; Wu, Weixiang

    2013-11-01

    Anaerobic ammonium-N removal from modified greenhouse turtle breeding wastewater with different chemical oxygen demand (COD) strengths (194.0-577.8 mg L(-1)) at relatively fixed C/N ratios (≈ 2) was investigated using a lab-scale up-flow anaerobic sludge blanket (UASB) anammox reactor. During the entire experiment, the total nitrogen (TN) removal efficiency was about 85% or higher, while the average COD removal efficiency was around 56.5 ± 7.9%. Based on the nitrogen and carbon balance, the nitrogen removal contribution was 79.6 ± 4.2% for anammox, 12.7 ± 3.0% for denitrification+denitritation and 7.7 ± 4.9% for other mechanisms. Denaturing gradient gel electrophoresis (DGGE) analyses revealed that Planctomycete, Proteobacteria and Chloroflexi bacteria were coexisted in the reactor. Anammox was always dominant when the reactor was fed with different COD concentrations, which indicated the stability of the anammox process with the coexistence of the denitrification process in treating greenhouse turtle breeding wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. The anammoxosome: an intracytoplasmic compartment in anammox bacteria.

    Science.gov (United States)

    van Niftrik, Laura A; Fuerst, John A; Sinninghe Damsté, Jaap S; Kuenen, J Gijs; Jetten, Mike S M; Strous, Marc

    2004-04-01

    Anammox bacteria belong to the phylum Planctomycetes and perform anaerobic ammonium oxidation (anammox); they oxidize ammonium with nitrite as the electron acceptor to yield dinitrogen gas. The anammox reaction takes place inside the anammoxosome: an intracytoplasmic compartment bounded by a single ladderane lipid-containing membrane. The anammox bacteria, first found in a wastewater treatment plant in The Netherlands, have the potential to remove ammonium from wastewater without the addition of organic carbon. Very recently anammox bacteria were also discovered in the Black Sea where they are responsible for 30-50% of the nitrogen consumption. This review will introduce different forms of intracytoplasmic membrane systems found in prokaryotes and discuss the compartmentalization in anammox bacteria and its possible functional relation to catabolism and energy transduction.

  2. Abundance and Diversity of Denitrifying and Anammox Bacteria in Seasonally Hypoxic and Sulfidic Sediments of the Saline Lake Grevelingen

    Science.gov (United States)

    Lipsewers, Yvonne A.; Hopmans, Ellen C.; Meysman, Filip J. R.; Sinninghe Damsté, Jaap S.; Villanueva, Laura

    2016-01-01

    Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity, and potential activity of denitrifying, anammox, and sulfide-dependent denitrifying bacteria in the sediments of the seasonally hypoxic saline Lake Grevelingen, known to harbor an active microbial community involved in sulfur oxidation pathways. Depth distributions of 16S rRNA gene, nirS gene of denitrifying and anammox bacteria, aprA gene of sulfur-oxidizing and sulfate-reducing bacteria, and ladderane lipids of anammox bacteria were studied in sediments impacted by seasonally hypoxic bottom waters. Samples were collected down to 5 cm depth (1 cm resolution) at three different locations before (March) and during summer hypoxia (August). The abundance of denitrifying bacteria did not vary despite of differences in oxygen and sulfide availability in the sediments, whereas anammox bacteria were more abundant in the summer hypoxia but in those sediments with lower sulfide concentrations. The potential activity of denitrifying and anammox bacteria as well as of sulfur-oxidizing, including sulfide-dependent denitrifiers and sulfate-reducing bacteria, was potentially inhibited by the competition for nitrate and nitrite with cable and/or Beggiatoa-like bacteria in March and by the accumulation of sulfide in the summer hypoxia. The simultaneous presence and activity of organoheterotrophic denitrifying bacteria, sulfide-dependent denitrifiers, and anammox bacteria suggests a tight network of bacteria coupling carbon-, nitrogen-, and sulfur cycling in Lake Grevelingen sediments. PMID:27812355

  3. Abundance and diversity of denitrifying and anammox bacteria in seasonally hypoxic and sulfidic sediments of the saline Lake Grevelingen

    Directory of Open Access Journals (Sweden)

    Yvonne A. Lipsewers

    2016-10-01

    Full Text Available Denitrifying and anammox bacteria are involved in the nitrogen cycling in marine sediments but the environmental factors that regulate the relative importance of these processes are not well constrained. Here, we evaluated the abundance, diversity and potential activity of denitrifying, anammox, and sulfide-dependent denitrifying bacteria in the sediments of the seasonally hypoxic saline Lake Grevelingen, known to harbor an active microbial community involved in sulfur oxidation pathways. Depth distributions of 16S rRNA gene, nirS gene of denitrifying and anammox bacteria, aprA gene of sulfur-oxidizing and sulfate-reducing bacteria, and ladderane lipids of anammox bacteria were studied in sediments impacted by seasonally hypoxic bottom waters. Samples were collected down to 5 cm depth (1 cm resolution at three different locations before (March and during summer hypoxia (August. The abundance of denitrifying bacteria did not vary despite of differences in oxygen and sulfide availability in the sediments, whereas anammox bacteria were more abundant in the summer hypoxia but in those sediments with lower sulfide concentrations. The potential activity of denitrifying and anammox bacteria as well as of sulfur-oxidizing, including sulfide-dependent denitrifiers and sulfate-reducing bacteria, was potentially inhibited by the competition for nitrate and nitrite with cable and/or Beggiatoa-like bacteria in March and by the accumulation of sulfide in the summer hypoxia. The simultaneous presence and activity of organoheterotrophic denitrifying bacteria, sulfide-dependent denitrifiers and anammox bacteria suggests a tight network of bacteria coupling carbon-, nitrogen- and sulfur cycling in Lake Grevelingen sediments.

  4. Nitrogen removal performance of anaerobic ammonia oxidation (ANAMMOX) in presence of organic matter.

    Science.gov (United States)

    Zhu, Weiqiang; Zhang, Peiyu; Yu, Deshuang; Dong, Huiyu; Li, Jin

    2017-06-01

    A sequencing batch reactor (SBR) was used to test the nitrogen removal performance of anaerobic ammonium oxidation (ANAMMOX) in presence of organic matter. Mesophilic operation (30 ± 0.5 °C) was performed with influent pH 7.5. The results showed, independent of organic matter species, ANAMMOX reaction was promoted when COD was lower than 80 mg/L. However, specific ANAMMOX activity decreased with increasing organic matter content. Ammonium removal efficiency decreased to 80% when COD of sodium succinate, sodium potassium tartrate, peptone and lactose were 192.5, 210, 225 and 325 mg/L, respectively. The stoichiometry ratio resulting from different OM differed largely and R 1 could be as an indicator for OM inhibition. When COD concentration was 240 mg/L, the loss of SAA resulting from lactose, peptone, sodium potassium tartrate and sodium succinate were 28, 36, 50 and 55%, respectively. Sodium succinate had the highest inhibitory effect on SAA. When ANAMMOX process was used to treat wastewater containing OM, the modified Logistic model could be employed to predict the NRE max .

  5. High-throughput profiling of microbial community structures in an ANAMMOX-UASB reactor treating high-strength wastewater.

    Science.gov (United States)

    Cao, Shenbin; Du, Rui; Li, Baikun; Ren, Nanqi; Peng, Yongzhen

    2016-07-01

    In this study, the microbial community structure was assessed in an anaerobic ammonium oxidation-upflow anaerobic sludge blanket (ANAMMOX-UASB) reactor treating high-strength wastewater (approximately 700 mg N L(-1) in total nitrogen) by employing Illumina high-throughput sequencing analysis. The reactor was started up and reached a steady state in 26 days by seeding mature ANAMMOX granules, and a high nitrogen removal rate (NRR) of 2.96 kg N m(-3) day(-1) was obtained at 13.2∼17.6 °C. Results revealed that the abundance of ANAMMOX bacteria increased during the operation, though it occupied a low proportion in the system. The phylum Planctomycetes was only 8.39 % on day 148 and Candidatus Brocadia was identified as the dominant ANAMMOX species with a percentage of 2.70 %. The phylum of Chloroflexi, Bacteroidetes, and Proteobacteria constituted a percentage up to 70 % in the community, of which the Chloroflexi and Bacteroidetes were likely to be related to the sludge granulation. In addition, it was found that heterotrophic denitrifying bacteria of Denitratisoma belonging to Proteobacteria phylum occupied a large proportion (22.1∼23.58 %), which was likely caused by the bacteria lysis and decay with the internal carbon source production. The SEM images also showed that plenty of other microorganisms existed in the ANAMMOX-UASB reactor.

  6. Influence of biomass acclimation on the performance of a partial nitritation-anammox reactor treating industrial saline effluents.

    Science.gov (United States)

    Giustinianovich, Elisa A; Campos, José-Luis; Roeckel, Marlene D; Estrada, Alejandro J; Mosquera-Corral, Anuska; Val Del Río, Ángeles

    2018-03-01

    The performance of the partial nitritation/anammox processes was evaluated for the treatment of fish canning effluents. A sequencing batch reactor (SBR) was fed with industrial wastewater, with variable salt and total ammonium nitrogen (TAN) concentrations in the range of 1.75-18.00 g-NaCl L -1 and 112 - 267 mg-TAN L -1 . The SBR operation was divided into two experiments: (A) progressive increase of salt concentrations from 1.75 to 18.33 g-NaCl L -1 ; (B) direct application of high salt concentration (18 g-NaCl L -1 ). The progressive increase of NaCl concentration provoked the inhibition of the anammox biomass by up to 94% when 18 g-NaCl L -1 were added. The stable operation of the processes was achieved after 154 days when the nitrogen removal rate was 0.021 ± 0.007 g N/L·d (corresponding to 30% of removal efficiency). To avoid the development of NOB activity at low salt concentrations and to stabilize the performance of the processes dissolved oxygen was supplied by intermittent aeration. A greater removal rate of 0.029 ± 0.017 g-N L -1 d -1 was obtained with direct exposure of the inoculum to 18 g-NaCl L -1 in less than 40 days. Also, higher specific activities than those from the inoculum were achieved for salt concentrations of 15 and 20 g-NaCl L -1 after 39 days of operation. This first study of the performance of the partial nitritation/anammox processes, to treat saline wastewaters, indicates that the acclimation period can be avoided to shorten the start-up period for industrial application purposes. Nevertheless, further experiments are needed in order to improve the efficiency of the processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Microbial resource management of one‐stage partial nitritation/anammox

    OpenAIRE

    Vlaeminck, S. E.; De Clippeleir, H.; Verstraete, W.

    2012-01-01

    Summary About 30 full‐scale partial nitritation/anammox plants are established, treating mostly sewage sludge reject water, landfill leachate or food processing digestate. Although two‐stage and one‐stage processes each have their advantages, the one‐stage configuration is mostly applied, termed here as oxygen‐limited autotrophic nitrification/denitrification (OLAND), and is the focus of this review. The OLAND application domain is gradually expanding, with technical‐scale plants on source‐se...

  8. Coexistence of nitrifying, anammox and denitrifying bacteria in a sequencing batch reactor

    Directory of Open Access Journals (Sweden)

    Michela eLangone

    2014-02-01

    Full Text Available Elevated nitrogen removal efficiencies from ammonium-rich wastewaters have been demonstrated by several applications, that combine nitritation and anammox processes. Denitrification will occur simultaneously when organic carbon is also present. In this study, the activity of aerobic ammonia oxidizing, anammox and denitrifying bacteria in a full scale Sequencing Batch Reactor, treating digester supernatants, was studied by means of batch-assays. AOB and anammox activities were maximum at pH of 8.0 and 7.8-8.0, rispectively. Short term effect of nitrite on anammox activity was studied, showing nitrite up to 42 mg/L did not result in inhibition. Both denitrification via nitrate and nitrite were measured. To reduce nitrite-oxidizing activity, high of NH3 – N (1.9-10 mg N-NH3/L and low nitrite (3-8 mg TNN/L are required conditions during the whole SBR cycle.Molecular analysis showed the nitritation-anammox sludge harbored a high microbial diversity, where each microorganism has a specific role. Using ammonia monooxygenase α –subunit (amoA gene as a marker, our analyses suggested different macro- and micro-environments in the reactor strongly affect the AOB community, allowing the development of different AOB species, such as N. europaea/eutropha and N. oligotropha groups, which improve the stability of nitritation process. A specific PCR primer set, used to target the 16S rRNA gene of anammox bacteria, confirmed the presence of the Ca. Brocadia fulgida type, able to grow in precence of organic matter and to tolerate high nitrite concentrations. The diversity of denitrifiers was assessed by using dissimilatory nitrite reductase (nirS gene-based analyses, who showed denitifiers were related to different betaproteobacterial genera, such as Thauera, Pseudomonas, Dechloromonas and Aromatoleum, able to assist in forming microbial aggregates. Concerning possible secondary processes, no n-damo bacteria were found while NOB from the genus of Nitrobacter

  9. Sustainable operation of submerged Anammox membrane bioreactor with recycling biogas sparging for alleviating membrane fouling.

    Science.gov (United States)

    Li, Ziyin; Xu, Xindi; Xu, Xiaochen; Yang, FengLin; Zhang, ShuShen

    2015-12-01

    A submerged anaerobic ammonium oxidizing (Anammox) membrane bioreactor with recycling biogas sparging for alleviating membrane fouling has been successfully operated for 100d. Based on the batch tests, a recycling biogas sparging rate at 0.2m(3)h(-1) was fixed as an ultimate value for the sustainable operation. The mixed liquor volatile suspended solid (VSS) of the inoculum for the long operation was around 3000mgL(-1). With recycling biogas sparging rate increasing stepwise from 0 to 0.2m(3)h(-1), the reactor reached an influent total nitrogen (TN) up to 1.7gL(-1), a stable TN removal efficiency of 83% and a maximum specific Anammox activity (SAA) of 0.56kg TNkg(-1) VSSd(-1). With recycling biogas sparging rate at 0.2 m(3) h(-1) (corresponding to an aeration intensity of 118m(3)m(-2)h(-1)), the membrane operation circle could prolong by around 20 times compared to that without gas sparging. Furthermore, mechanism of membrane fouling was proposed. And with recycling biogas sparging, the VSS and EPS content increasing rate in cake layer were far less than the ones without biogas sparging. The TN removal performance and sustainable membrane operation of this system showed the appealing potential of the submerged Anammox MBR with recycling biogas sparging in treating high-strength nitrogen-containing wastewaters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Current perspectives on the application of N-damo and anammox in wastewater treatment.

    Science.gov (United States)

    van Kessel, Maartje Ahj; Stultiens, Karin; Slegers, Monique Fw; Guerrero Cruz, Simon; Jetten, Mike Sm; Kartal, Boran; Op den Camp, Huub Jm

    2018-02-22

    The efficient treatment of wastewater for the removal of nitrogen is of key importance to prevent eutrophication and deoxygenation of receiving water bodies. In addition, ineffective wastewater treatment can be a source of greenhouse gasses. The application of newly discovered microbial processes, such as nitrite/nitrate-dependent methane oxidation (N-damo), can make wastewater treatment systems more sustainable; especially when they are combined with anaerobic ammonium oxidation (anammox). A treatment system based on these microbial processes will need oxygen supply for the production of nitrite. This oxygen may inhibit N-damo and anammox and careful regulation of the oxygen supply is of key importance for the success of the application of N-damo in wastewater treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Engineering application of anaerobic ammonium oxidation process in wastewater treatment.

    Science.gov (United States)

    Mao, Nianjia; Ren, Hongqiang; Geng, Jinju; Ding, Lili; Xu, Ke

    2017-08-01

    Anaerobic ammonium oxidation (Anammox), a promising biological nitrogen removal process, has been verified as an efficient, sustainable and cost-effective alternative to conventional nitrification and denitrification processes. To date, more than 110 full-scale anammox plants have been installed and are in operation, treating industrial NH 4 + -rich wastewater worldwide, and anammox-based technologies are flourishing. This review the current state of the art for engineering applications of the anammox process, including various anammox-based technologies, reactor selection and attempts to apply it at different wastewater plants. Process control and implementation for stable performance are discussed as well as some remaining issues concerning engineering application are exposed, including the start-up period, process disturbances, greenhouse gas emissions and especially mainstream anammox applications. Finally, further development of the anammox engineering application is proposed in this review.

  12. The kinetics of nitrogen removal and biogas production in an anammox non-woven membrane reactor.

    Science.gov (United States)

    Ni, Shou-Qing; Lee, Po-Heng; Sung, Shihwu

    2010-08-01

    The anammox non-woven membrane reactor (ANMR) is a novel reactor configuration to culture the slowly growing anammox bacteria. Different mathematical models were used to study the process kinetics of the nitrogen removal in the ANMR. The kinetics of nitrogen gas production of anammox process was first evaluated in this paper. For substrate removal kinetics, the modified Stover-Kincannon model and the Grau second-order model were more applicable to the ANMR than the first-order model and the Monod model. For nitrogen gas production kinetics, the Van der Meer and Heertjes model was more appropriate than the modified Stover-Kincannon model. Model evaluation was carried out by comparing experimental data with predicted values calculated from suitable models. Both model kinetics study and model testing showed that the Grau second-order model and the Van der Meer and Heertjes model seemed to be the best models to describe the nitrogen removal and nitrogen gas production in the ANMR, respectively. (c) 2010 Elsevier Ltd. All rights reserved.

  13. Rate processes in gas phase

    International Nuclear Information System (INIS)

    Hansen, C.F.

    1983-05-01

    Reaction-rate theory and experiment are given a critical review from the engineers' point of view. Rates of heavy-particle, collision-induced reaction in gas phase are formulated in terms of the cross sections and activation energies of the reaction. The effect of cross section function shape and of excited state contributions to the reaction both cause the slope of Arrhenius plots to differ from the true activation energy, except at low temperature. The master equations for chemically reacting gases are introduced, and dissociation and ionization reactions are shown to proceed primarily from excited states about kT from the dissociation or ionization limit. Collision-induced vibration, vibration-rotation, and pure rotation transitions are treated, including three-dimensional effects and conservation of energy, which have usually been ignored. The quantum theory of transitions at potential surface crossing is derived, and results are found to be in fair agreement with experiment in spite of some questionable approximations involved

  14. Development of anaerobic ammonium oxidation (anammox) for biological nitrogen removal in domestic wastewater treatment (Case study: Surabaya City, Indonesia)

    Science.gov (United States)

    Wijaya, I. Made Wahyu; Soedjono, Eddy Setiadi; Fitriani, Nurina

    2017-11-01

    Domestic wastewater effluent is the main contributor to diverse water pollution problems. The contaminants contained in the wastewater lead the low quality of water. The presence of ammonium and nitrate along with phosphorus are potentially cause eutrophication and endanger aquatic life. Excess nutrients, mostly N and P is the main cause of eutrophication which is result in oxygen depletion, biodiversity reduction, fish kills, odor and increased toxicity. Most of the domestic wastewater in Surabaya City still contains nitrogen that exceeded the threshold. The range of ammonium and orthophosphate concentration in the domestic wastewater is between 6.29 mg/L - 38.91 mg/L and 0.44 mg/L - 1.86 mg/L, respectively. An advance biological nitrogen removal process called anammox is a sustainable and cost effective alternative to the basic method of nitrogen removal, such as nitrification and denitrification. Many research have been conducted through anammox and resulted promisingly way to remove nitrogen. In this process, ammonium will be oxidized with nitrite as an electron acceptor to produce nitrogen gas and low nitrate in anoxic condition. Anammox requires less oxygen demand, no needs external carbon source, and low operational cost. Based on its advantages, anammox is possible to apply in domestic wastewater treatment in Surabaya with many further studies.

  15. A coupled system of half-nitritation and ANAMMOX for mature landfill leachate nitrogen removal.

    Science.gov (United States)

    Li, Yun; Li, Jun; Zhao, Baihang; Wang, Xiujie; Zhang, Yanzhuo; Wei, Jia; Bian, Wei

    2017-09-01

    A coupled system of membrane bioreactor-nitritation (MBR-nitritation) and up-flow anaerobic sludge blanket-anaerobic ammonium oxidation (UASB-ANAMMOX) was employed to treat mature landfill leachate containing high ammonia nitrogen and low C/N. MBR-nitritation was successfully realized for undiluted mature landfill leachate with initial concentrations of 900-1500 mg/L [Formula: see text] and 2000-4000 mg/L chemical oxygen demand. The effluent [Formula: see text] concentration and the [Formula: see text] accumulation efficiency were 889 mg/L and 97% at 125 d, respectively. Half-nitritation was quickly realized by adjustment of hydraulic retention time and dissolved oxygen (DO), and a low DO control strategy could allow long-term stable operation. The UASB-ANAMMOX system showed high effective nitrogen removal at a low concentration of mature landfill leachate. The nitrogen removal efficiency was inhibited at excessive influent substrate concentration and the nitrogen removal efficiency of the system decreased as the concentration of mature landfill leachate increased. The MBR-nitritation and UASB-ANAMMOX processes were coupled for mature landfill leachate treatment and together resulted in high effective nitrogen removal. The effluent average total nitrogen concentration and removal efficiency values were 176 mg/L and 83%, respectively. However, the average nitrogen removal load decreased from 2.16 to 0.77 g/(L d) at higher concentrations of mature landfill leachate.

  16. Microbial dynamics of biofilm and suspended flocs in anammox membrane bioreactor: The effect of non-woven fabric membrane.

    Science.gov (United States)

    Ren, Long-Fei; Lv, Lu; Kang, Qi; Gao, Baoyu; Ni, Shou-Qing; Chen, Yi-Han; Xu, Shiping

    2018-01-01

    Membrane bioreactor with non-woven fabric membranes (NWMBR) is developing into a suitable method for anaerobic ammonium oxidation (anammox). As a carrier, non-woven fabric membrane divided total biomass into biofilm and suspended flocs gradually. Total nitrogen removal efficiency was maintained around 82.6% under nitrogen loading rate of 567.4mgN/L/d after 260days operation. Second-order substrate removal and Stover-Kincannon models were successfully used to simulate the nitrogen removal performance in NWMBR. High-throughput sequence was employed to elucidate the underlying microbial community dynamics. Candidatus Brocadia, Kuenenia, Jettenia were detected to affirm the dominant status of anammox microorganisms and 98.2% of anammox microorganisms distributed in biofilm. In addition, abundances of functional genes (hzs, nirK) in biofilm and suspended flocs were assessed by quantitative PCR to further investigate the coexistence of anammox and other microorganisms. Potential nitrogen removal pathways were established according to relevant nitrogen removal performance and microbial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Community N and O isotope fractionation by sulfide-dependent denitrification and anammox in a stratified lacustrine water column

    Science.gov (United States)

    Wenk, Christine B.; Zopfi, Jakob; Blees, Jan; Veronesi, Mauro; Niemann, Helge; Lehmann, Moritz F.

    2014-01-01

    We investigated the community nitrogen (N) and oxygen (O) isotope effects of fixed N loss in the northern basin of Lake Lugano, where sulfide-dependent denitrification and anammox are the main drivers of suboxic N2 production. A decrease in nitrate (NO3-) concentration toward the redox transition zone (RTZ) at mid-water depth was paralleled by an increase in δ15N and δ18O from approximately 5‰ to >20‰ and from 0‰ to >10‰, respectively. Ammonium (NH4+) concentrations were highest in the near-bottom water and decreased toward the RTZ concomitant with an increase in δ15N-NH4+ from ∼7‰ to >15‰. A diffusion-reaction model yielded N and O isotope enrichment factors that are significantly smaller than isotope effects reported previously for microbial NO3- reduction and NH4+ oxidation (15εNO3 ≈ 10‰, 18εNO3 ≈ 7‰, and 15εNH4 ≈ 10-12‰). For the Lake Lugano north basin, we constrain the apparent under-expression of the N isotope effects to: (1) environmental conditions (e.g., substrate limitation, low cell specific N transformation rates), or (2) low process-specific (chemolithotrophic denitrification and anammox) isotope fractionation. Our results have confirmed the robust nature of the co-linearity between N and O isotope enrichment during microbial denitrification beyond its organotrophic mode. However, the ratio of 18O to 15N enrichment (18εNO3:15εNO3) associated with NO3- reduction in the RTZ was ∼0.89, which is lower than observed in marine environments and in most culture experiments. We propose that chemolithotrophic NO3- reduction in the Lake Lugano north basin was partly catalyzed by the periplasmic dissimilatory nitrate reductase (Nap) (rather than the membrane-bound dissimilatory Nar), which is known to express comparably low 18εNO3:15εNO3 ratios in the ambient NO3- pool. However, NO2- re-oxidation, e.g., during anammox or microaerobic nitrification, could have contributed to the lowered 18O to 15N enrichment ratios. Although

  18. High rates of denitrification and nitrous oxide emission in arid biological soil crusts from the Sultanate of Oman

    DEFF Research Database (Denmark)

    Abed, Raeid M M; Lam, Phyllis; De Beer, Dirk

    2013-01-01

    Using a combination of process rate determination, microsensor profiling and molecular techniques, we demonstrated that denitrification, and not anaerobic ammonium oxidation (anammox), is the major nitrogen loss process in biological soil crusts from Oman. Potential denitrification rates were 584...... that nitrogen loss via denitrification is a dominant process in crusts from Oman, which leads to N 2 O gas emission and potentially reduces desert soil fertility....

  19. Novel anammox bacteria and nitrogen loss from Lake Superior

    DEFF Research Database (Denmark)

    Crowe, Sean A.; Treusch, Alexander H.; Forth, Michael

    2017-01-01

    Anaerobic ammonium oxidizing (anammox) bacteria own a central position in the global N-cycle, as they have the ability to oxidize NH4 + to N2 under anoxic conditions using NO2 -. They are responsible for up to 50% of all N2 released from marine ecosystems into the atmosphere and are thus...... indispensible for balancing the activity of N-fixing bacteria and completing the marine N-cycle. The contribution, diversity, and impact of anammox bacteria in freshwater ecosystems, however, is largely unknown, confounding assessments of their role in the global N-cycle. Here we report the activity...... within Lake Superior and those described from other locations. Our data thus reveal that novel anammox bacteria underpin N-loss from Lake Superior, and if more broadly distributed across inland waters would play an important role in continental N-cycling and mitigation of fixed nitrogen transfer from...

  20. Minimum Entropy Rate Simplification of Stochastic Processes.

    Science.gov (United States)

    Henter, Gustav Eje; Kleijn, W Bastiaan

    2016-02-23

    This document contains supplemental material for the IEEE Transactions on Pattern Analysis and Machine Intelligence article "Minimum Entropy Rate Simplification of Stochastic Processes." The supplement is divided into three appen- dices: the first on MERS for Gaussian processes, and the remaining two on, respectively, the theory and the experimental results of MERS for Markov chains.

  1. Effect of increase in salinity on ANAMMOX-UASB reactor stability.

    Science.gov (United States)

    Xing, Hui; Wang, Han; Fang, Fang; Li, Kai; Liu, Lianwei; Chen, Youpeng; Guo, Jinsong

    2017-05-01

    The effect of salinity on the anaerobic ammonium oxidation (ANAMMOX) process in a UASB reactor was investigated by analysing ammonium, nitrite, nitrate and TN concentrations, and TN removal efficiency. Extracellular polymeric substances (EPSs) and specific ANAMMOX activity (SAA) were evaluated. Results showed the effluent deteriorated after salinity was increased from 8 to 13 g/L and from 13 to 18 g/L, and TN removal efficiency decreased from 80% to 30% and 80% to 50%, respectively. However, ANAMMOX performance recovered and TN removal efficiency increased to 80% after 40 days when the influent concentrations of [Formula: see text] and [Formula: see text] were 200 mg/L and salinity levels were at 13 and 18 g/L, respectively. The amount of EPSs decreased from 58.9 to 37.1 mg/g volatile suspended solids (VSS) when the reactor was shocked by salinity of 13 g/L, and then increased to 57.2 mg/g VSS when the reactor recovered and ran stably at 13 g/L. The amount of EPSs decreased from 57.2 to 49.1 mg/g VSS when the reactor was shocked by salinity of 18 g/L, and then increased to 60.7 mg/g VSS when the reactor recovered and ran stably at 18 g/L. The amount of EPS and the amounts of polysaccharide, protein and humus showed no evident difference when the reactor recovered from different levels of salinity shocks. Batch tests showed salinity shock load from 8 to 38 g/L inhibited the SAA. However, when the reactor recovered from salinity shocks, SAA was higher compared to that when the reactor was subjected to the same level of salinity shock.

  2. Quantum mechanics of molecular rate processes

    CERN Document Server

    Levine, Raphael D

    1999-01-01

    This survey of applications of the theory of collisions and rate processes to molecular problems explores collisions of molecules with internal structure, generalized Ehrenfest theorem, theory of reactive collisions, and role of symmetry. It also reviews partitioning technique, equivalent potentials and quasibound states, theory of direct reactions, more. 1969 edition.

  3. Anammox sludge immobilized in polyvinyl alcohol (PVA) cryogel carriers

    Science.gov (United States)

    This study evaluated the use of polyvinyl alcohol (PVA) cryogels to encapsulate slow-growing anammox bacteria for deammonification treatment of wastewater. The cryogel pellets were prepared by a freezing-thawing procedure at -8 oC. On average, pellets contained 11.8 mg TSS/g-pellet of enriched anamm...

  4. Evaluation of oxygen adaptation and identification of functional bacteria composition for anammox consortium in non-woven biological rotating contactor.

    Science.gov (United States)

    Liu, Sitong; Yang, Fenglin; Xue, Yuan; Gong, Zheng; Chen, Huihui; Wang, Tao; Su, Zhencheng

    2008-11-01

    In this study, the anammox consortium was found to adapt to the wastewater containing dissolved oxygen (DO), as the DO was gradually increased. Batch tests indicated the maximum aerobic ammonium oxidizing activity of the consortium was 1.38mmolNH4+-N(gVSS)(-1)day(-1), which played key roles in the oxygen consumption process; the maximum anaerobic ammonium oxidizing activity was slightly decreased after long-term oxygen exposure, but only from 21.23mmolNH4+-N(gVSS)(-1)day(-1) to 20.23mmolNH4+-N(gVSS)(-1)day(-1). Microbiological community analysis identified two strains similar to Nitrosomonas eutropha were responsible for oxygen consumption, which were able to exist in the autotrophic anaerobic condition for long periods and protect anammox bacteria Planctomycetales from the influence of oxygen. Microbiological composition analysis showed Nitrosomonas and Planctomycetales approximately accounted for 10% and 70% of the bacteria, respectively. The possibility of cultivation anammox consortium in presence of DO will lead to substantial savings of energy and resource in the industrial application.

  5. Nitrogen cycling process rates across urban ecosystems.

    Science.gov (United States)

    Reisinger, Alexander J; Groffman, Peter M; Rosi-Marshall, Emma J

    2016-09-21

    Nitrogen (N) pollution of freshwater, estuarine, and marine ecosystems is widespread and has numerous environmental and economic impacts. A portion of this excess N comes from urban watersheds comprised of natural and engineered ecosystems which can alter downstream N export. Studies of urban N cycling have focused on either specific ecosystems or on watershed-scale mass balances. Comparisons of specific N transformations across ecosystems are required to contextualize rates from individual studies. Here we reviewed urban N cycling in terrestrial, aquatic, and engineered ecosystems, and compared N processing in these urban ecosystem types to native reference ecosystems. We found that net N mineralization and net nitrification rates were enhanced in urban forests and riparian zones relative to reference ecosystems. Denitrification was highly variable across urban ecosystem types, but no significant differences were found between urban and reference denitrification rates. When focusing on urban streams, ammonium uptake was more rapid than nitrate uptake in urban streams. Additionally, reduction of stormwater runoff coupled with potential decreases in N concentration suggests that green infrastructure may reduce downstream N export. Despite multiple environmental stressors in urban environments, ecosystems within urban watersheds can process and transform N at rates similar to or higher than reference ecosystems. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. [Influence of alkalinity and DO on ANAMMOX bioreactor at normal temperature and low substrate concentration].

    Science.gov (United States)

    Ren, Yu-Hui; Wang, Ke; Li, Xiang-Kun; Ma, Kai-Li; Zhang, Jie

    2014-11-01

    A lab-scale up-flow ANAMMOX bioreactor with ceramics as biomass carrier was started up. The influence of alkalinity and dissolved oxygen on ANAMMOX reaction at normal temperature and low substrate concentration was investigated. The results showed that, at (20 ± 2) degrees C and an HRT of 3 h, when the alkalinity was between 44 mg x L(-1) and 350 mg x L(-1), the ammonia removal efficiency was decreased from 97.2% to 75.6% and the TN removal efficiency was decreased from 89.7% to 75.1% as the alkalinity reduced. Meanwhile, the nitrite removal efficiency was stabilized at 99.7%. When the alkalinity was 0 mg x L(-1), the effluent nitrite concentration was increased to 4.9 mg x L(-1). Ammonia removal efficiency was decreased by 12.3% because of light. When the HRT was 1.5 h, the DO value was < 3 mg x L(-1), the average removal efficiencies of ammonia and nitrite were 99.7% and 100%, respectively, the nitrogen removal rate was 1.0 kg x (m3 x d)(-1). 16S rRNA phylogenic analysis was applied to analyze the microbial community structure. Results revealed that Candidatus Jettenia asiatica and Candidatus Brocadia sp. were adapted to normal temperature.

  7. Hot topics and application trends of the anammox biotechnology: a review by bibliometric analysis

    OpenAIRE

    Zhang, Zuotao; Liu, Sitong

    2014-01-01

    Anammox has been extensively identified as a novel and sustained biotechnology for wastewater treatment. This study was conducted to evaluate the hot topics and application trends of anammox biotechnology by bibliometric analysis. The results show that “Water science and technology” and “Environmental science ecology” are the prevalent journal and category in this field. Many researches about “process” and “inhibition” have been carried out to conquer common challenges of anammox biotechnolog...

  8. [Cultivation of ANAMMOX bacteria and the ammonium anaerobic oxidation technology in the plug flow bio-reactor].

    Science.gov (United States)

    Liu, Yin; Du, Bing; Si, Ya-an; Sun, Yan-ling; Shen, Li-xian

    2005-03-01

    It is feasible that the ANAMMOX bacteria can be enriched and cultivated to red granular in plug flow immobilized floc bioreactor. Average ammonium and nitrite removal rate are more than 98 %, and average total nitrogen removal rate is 86% combined with 14% nitrate production; the removal volumetric total nitrogen load is 2.56kg/(m3 x d). The influence of the influent substrate ratio of ammonium to nitrite on reactor's performance has been studied. The granule structure has been observed by the scan electro-microscope.

  9. Enrichment of Anammox biomass from municipal activated sludge: experimental and modelling results

    NARCIS (Netherlands)

    Dapena-Mora, A.; Hulle, S.W.H. van; Campos, J.L.; Mendez, R.; Rolleghem, P.A. van; Jetten, M.S.M.

    2004-01-01

    Anaerobic Ammonia Oxidising (Anammox) biomass was enriched from sludge collected at a municipal wastewater treatment plant, employing a Sequential Batch Reactor (SBR). After 60 days Anammox activity started to be detected, by consumption of stoichiometric amounts of NO2- and NH4+ in the system.

  10. Microbial resource management of one-stage partial nitritation/anammox.

    Science.gov (United States)

    Vlaeminck, S E; De Clippeleir, H; Verstraete, W

    2012-05-01

    About 30 full-scale partial nitritation/anammox plants are established, treating mostly sewage sludge reject water, landfill leachate or food processing digestate. Although two-stage and one-stage processes each have their advantages, the one-stage configuration is mostly applied, termed here as oxygen-limited autotrophic nitrification/denitrification (OLAND), and is the focus of this review. The OLAND application domain is gradually expanding, with technical-scale plants on source-separated domestic wastewater, pre-treated manure and sewage, and liquors from organic waste bioenergy plants. A 'microbial resource management' (MRM) OLAND framework was elaborated, showing how the OLAND engineer/operator (1: input) can design/steer the microbial community (2: biocatalyst) to obtain optimal functionality (3: output). In the physicochemical toolbox (1), design guidelines are provided, as well as advantages of different reactor technologies. Particularly the desirable aeration regime, feeding regime and shear forces are not clear yet. The development of OLAND trickling filters, membrane bioreactors and systems with immobilized biomass is awaited. The biocatalyst box (2) considers 'Who': biodiversity and its dynamic patterns, 'What': physiology, and 'Where': architecture creating substrate gradients. Particularly community dynamics and extracellular polymeric substances (EPS) still require insights. Performant OLAND (3) comprises fast start-up (storage possibility; fast growth of anammox bacteria), process stability (endured biomass retention; stress resilience), reasonable overall costs, high nitrogen removal efficiency and a low environmental footprint. Three important OLAND challenges are elaborated in detailed frameworks, demonstrating how to maximize nitrogen removal efficiency, minimize NO and N(2)O emissions and obtain through OLAND a plant-wide net energy gain from sewage treatment. © 2012 The Authors. Microbial Biotechnology © 2012 Society for Applied

  11. The content of trace element iron is a key factor for competition between anaerobic ammonium oxidation and methane-dependent denitrification processes.

    Science.gov (United States)

    Lu, Yong-Ze; Fu, Liang; Li, Na; Ding, Jing; Bai, Ya-Nan; Samaras, Petros; Zeng, Raymond Jianxiong

    2018-05-01

    Coupling of anaerobic ammonium oxidation (Anammox) with denitrifying anaerobic methane oxidation (DAMO) is a sustainable pathway for nitrogen removal and reducing methane emissions from wastewater treatment processes. However, studies on the competitive relation between Anammox bacteria and DAMO bacteria are limited. Here, we investigated the effects of variations in the contents of trace element iron on Anammox and DAMO microorganisms. The short-term results indicated that optimal concentrations of iron, which obviously stimulated the activity of Amammox bacteria, DAMO bacteria and DAMO archaea, were 80, 20, and 80 μM, respectively. The activity of Amammox bacteria increased more significant than DAMO bacteria with increasing contents of trace element iron. After long-term incubation with high content of trace element iron of 160 μM in the medium, Candidatus Brocadia (Amammox bacteria) outcompeted Candidatus Methylomirabilis oxyfera (DAMO bacteria), and ANME-2d (DAMO archaea) remarkably increased in number and dominated the co-culture systems (64.5%). Meanwhile, with further addition of iron, the removal rate of ammonium and nitrate increased by 13.6 and 9.2 times, respectively, when compared with that noted in the control. As far as we know, this study is the first to explore the important role of trace element iron contents in the competition between Anammox bacteria and DAMO bacteria and further enrichment of DAMO archaea by regulating the contents of trace element iron. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Achieve efficient nitrogen removal from real sewage in a plug-flow integrated fixed-film activated sludge (IFAS) reactor via partial nitritation/anammox pathway.

    Science.gov (United States)

    Yang, Yandong; Zhang, Liang; Cheng, Jun; Zhang, Shujun; Li, Baikun; Peng, Yongzhen

    2017-09-01

    This study tested the feasibility of plug-flow integrated fixed-film activated sludge (IFAS) reactor in applying sewage partial nitritation/anammox (PN/A) process. The IFAS reactor was fed with real pre-treated sewage (C/N ratio=1.3) and operated for 200days. High nitrogen removal efficiency of 82% was achieved with nitrogen removal rates of 0.097±0.019kgN/(m 3 ·d). Therefore, plug-flow IFAS reactor could be an alternative to applying sewage PN/A process. Besides, it was found that the stability of sewage PN/A process was significantly affected by residual ammonium. Nitrate accumulated in effluent and PN/A performance deteriorated when residual ammonium was below 1mg/L. On the contrary, long-term stable PN/A operation was achieved when residual ammonium was over 3mg/L. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The contrast study of anammox-denitrifying system in two non-woven fixed-bed bioreactors (NFBR) treating different low C/N ratio sewage.

    Science.gov (United States)

    Gao, Fan; Zhang, Hanmin; Yang, Fenglin; Qiang, Hong; Zhang, Guangyi

    2012-06-01

    Two non-woven fixed-bed bioreactors (NFBR) based on different substrates (nitrite and nitrate) were constructed to study the environmental adaptability for temperature and organic matter of anammox-denitrifying system and nitrogen removal performance. The two reactors were successfully operated for 200 days. The average removal rates of nitrogen and COD of R2 were 81% and 93%, respectively. Besides, the nitrogen removal rate of R1 was 95% under not more than 105 mg/l of COD. The experimental results indicated that the R2 based on nitrate had a good nitrogen removal performance at room temperature (25 °C). Additionally, the analysis results of fluorescence in situ hybridization (FISH) showed that the percentage compositions of anammox in R1 and R2 were 84% and 65% on day 189. Finally, the possible nitrogen removal model of anammox-denitrifying system was constructed. According to nitrogen balance and C/N ratios of denitrification, the nitrogen removal approaches of R1 and R2 were obtained. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Comparing BV solutions of rate independent processes

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel; Recupero, V.

    2014-01-01

    Roč. 21, č. 1 (2014), s. 121-146 ISSN 0944-6532 R&D Projects: GA ČR GAP201/10/2315 Institutional support: RVO:67985840 Keywords : variational inequalities * rate independence * convex sets Subject RIV: BA - General Mathematics Impact factor: 0.552, year: 2014 http://www.heldermann.de/JCA/JCA21/JCA211/jca21006.htm

  15. Molecular diversity and distribution of anammox community in sediments of the Dongjiang River, a drinking water source of Hong Kong.

    Science.gov (United States)

    Sun, W; Xu, M-Y; Wu, W-M; Guo, J; Xia, C-Y; Sun, G-P; Wang, A-J

    2014-02-01

    The aim of this study was to characterize anaerobic ammonium oxidation (anammox) community in sediments of the Dongjiang River, a drinking water source of Hong Kong. The diversity and distribution of the anammox community were investigated based on a comparative analyses of 16S rRNA and hydrazine oxidation (hzo) genes of anammox bacteria. Candidatus Brocadia and two new anammox bacterial clusters were detected based on phylogenetic analysis of 16S rRNA genes. In contrast, the targeting of hzo genes indicated the presence of only Candidatus Jettenia with four different clusters. It was found that the sequence diversities of hzo genes were higher than those of the 16S rRNA genes. The abundance of anammox bacteria varied significantly among the sediment samples based on qPCR. Pearson correlation analysis indicated that nitrite concentration was the key factor influencing the abundance of anammox bacteria. The redundance analysis (RDA) confirmed that the combination of the contents of nitrite and nitrate, and the ratio of total nitrogen vs total carbon (TN/TC) had significant impact on the anammox bacterial community structure. The results revealed that the diverse anammox bacteria were present in sediments of the Dongjiang River, and the community structures were associated with varied environmental factors caused by urban pollutant invasion. This is the first report about the distribution of anammox bacterial community in sediments of the Dongjiang River, which provides helpful information of anammox niche specificity and influencing factors in the river ecosystem. © 2013 The Society for Applied Microbiology.

  16. The indeterminate rate problem for birth-death processes

    NARCIS (Netherlands)

    van Doorn, Erik A.

    1987-01-01

    A birth-death process is completely determined by its set of rates if and only if this set satisfies a certain condition C, say. If for a set of rates R the condition C is not fulfilled, then the problem arises of characterizing all birth-death processes which have rate set R (the indeterminate rate

  17. Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake

    Science.gov (United States)

    Stoliker, Deborah L.; Repert, Deborah A.; Smith, Richard L.; Song, Bongkeun; LeBlanc, Denis R.; McCobb, Timothy D.; Conaway, Christopher; Hyun, Sung Pil; Koh, Dong-Chan; Moon, Hee Sun; Kent, Douglas B.

    2016-01-01

    The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water chemistry, seepage rates and direction of groundwater flow, and the abundance and potential rates of activity of N-cycling microbial communities. Genes coding for denitrification, anaerobic ammonium oxidation (anammox), and nitrification were identified at all sites regardless of flow direction or groundwater dissolved oxygen concentrations. Flow direction was, however, a controlling factor in the potential for N-attenuation via denitrification in the sediments. Potential rates of denitrification varied from 6 to 4500 pmol N/g/h from the inflow to the outflow side of the lake, owing to fundamental differences in the supply of labile organic matter. The results of laboratory incubations suggested that when anoxia and limiting labile organic matter prevailed, the potential existed for concomitant anammox and denitrification. Where oxic lake water was downwelling, potential rates of nitrification at shallow depths were substantial (1640 pmol N/g/h). Rates of anammox, denitrification, and nitrification may be linked to rates of organic N-mineralization, serving to increase N-mobility and transport downgradient.

  18. Hydrologic Controls on Nitrogen Cycling Processes and Functional Gene Abundance in Sediments of a Groundwater Flow-Through Lake.

    Science.gov (United States)

    Stoliker, Deborah L; Repert, Deborah A; Smith, Richard L; Song, Bongkeun; LeBlanc, Denis R; McCobb, Timothy D; Conaway, Christopher H; Hyun, Sung Pil; Koh, Dong-Chan; Moon, Hee Sun; Kent, Douglas B

    2016-04-05

    The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water chemistry, seepage rates and direction of groundwater flow, and the abundance and potential rates of activity of N-cycling microbial communities. Genes coding for denitrification, anaerobic ammonium oxidation (anammox), and nitrification were identified at all sites regardless of flow direction or groundwater dissolved oxygen concentrations. Flow direction was, however, a controlling factor in the potential for N-attenuation via denitrification in the sediments. Potential rates of denitrification varied from 6 to 4500 pmol N/g/h from the inflow to the outflow side of the lake, owing to fundamental differences in the supply of labile organic matter. The results of laboratory incubations suggested that when anoxia and limiting labile organic matter prevailed, the potential existed for concomitant anammox and denitrification. Where oxic lake water was downwelling, potential rates of nitrification at shallow depths were substantial (1640 pmol N/g/h). Rates of anammox, denitrification, and nitrification may be linked to rates of organic N-mineralization, serving to increase N-mobility and transport downgradient.

  19. Developing Anammox for mainstream municipal wastewater treatment

    OpenAIRE

    Lotti, T.

    2016-01-01

    Conventional wastewater treatment plants (WWTPs), like activated sludge systems, are energy demanding requiring a large electrical energy supply (e.g. 25 kWh PE-1 year-1) which, especially during peak-load periods, may account for an important quote of the grid installed power of the surrounding area. Only across the EU, there are 16000 WWTPs that consume around 10000 GWh year-1 of electricity. Furthermore, the volume of wastewater treated in WWTPs in the EU is increasing with a rate of aroun...

  20. Anammox biomass carrying efficiency of polyethylene non-woven sheets as a carrier material.

    Science.gov (United States)

    Cho, Sunja; Jung, Minki; Ju, Dongjin; Lee, Young-Hee; Cho, Kuk; Okabe, Satoshi

    2017-07-31

    To access the effects of the surface modification and fabric structure of polyethylene (PE) non-woven fabric sheets on retaining the attachment efficiency of anammox biomass, three different non-woven sheets were prepared and inserted in an anammox reactor. The hydrophobic surface modification with 10% KMnO 4 and gelatin did not improve the attachment efficiency of the anammox biomass on the surface of the PE non-woven fibers. Densely packed PE-755 having the highest specific surface area to volume ratio (SA/V) (755) retained 221.4 mg biomass per unit sheet, whereas PE-181 having the lowest SA/V (181) retained only 66.4 mg biomass per unit. Accordingly, the volumetric anammox activity of non-woven sheet PE-755 was the highest among the three PE non-woven sheets because of the strong positive relationship between the specific anammox activity and biomass amount (R = 0.835, P non-woven biocarriers for anammox biomass.

  1. HAZARD RATE ESTIMATION OF TEMPORAL POINT PROCESS CASE STUDY: EARTHQUAKE HAZARD RATE IN NUSATENGGARA REGION

    OpenAIRE

    Sunusi, Nurtiti

    2008-01-01

    Hazard rate estimation is one of the important topics in forecasting earthquake occurrence. Forecasting earthquake occurrence is a part of the statistical seismology where the main subject is the point process. Generally, earthquake hazard rate is estimated based on the point process likelihood equation called the Hazard Rate Likelihood of Point Process (HRLPP). In this research, we have developed estimation method, that is hazard rate single decrement HRSD. This method was adapted from estim...

  2. Subexponential loss rate asymptotics for Lévy processes

    DEFF Research Database (Denmark)

    Andersen, Lars Nørvang

    We consider a Lévy process reflected in barriers at 0 and K > 0. The loss rate is the mean time spent at the upper barrier K at time 1 when the process is started in stationarity, and is a natural continuous-time analogue of the stationary expected loss rate for a reflected random walk. We derive...

  3. Start-Up Characteristics of a Granule-Based Anammox UASB Reactor Seeded with Anaerobic Granular Sludge

    Directory of Open Access Journals (Sweden)

    Lei Xiong

    2013-01-01

    Full Text Available The granulation of anammox sludge plays an important role in the high nitrogen removal performance of the anammox reactor. In this study, anaerobic granular sludge was selected as the seeding sludge to start up anammox reactor in order to directly obtain anammox granules. Results showed that the anammox UASB reactor was successfully started up by inoculating anaerobic granular sludge, with substrate capacity of 4435.2 mg/(L·d and average ammonium and nitrite removal efficiency of 90.36% and 93.29%, respectively. During the start-up course, the granular sludge initially disintegrated and then reaggregated and turned red, suggesting the high anammox performance. Zn-Fe precipitation was observed on the surface of granules during the operation by SEM-EDS, which would impose inhibition to the anammox activity of the granules. Accordingly, it is suggested to relatively reduce the trace metals concentrations, of Fe and Zn in the conventional medium. The findings of this study are expected to be used for a shorter start-up and more stable operation of anammox system.

  4. Start-Up Characteristics of a Granule-Based Anammox UASB Reactor Seeded with Anaerobic Granular Sludge

    Science.gov (United States)

    Wang, Yun-Yan; Tang, Chong-Jian; Chai, Li-Yuan; Xu, Kang-Que; Song, Yu-Xia

    2013-01-01

    The granulation of anammox sludge plays an important role in the high nitrogen removal performance of the anammox reactor. In this study, anaerobic granular sludge was selected as the seeding sludge to start up anammox reactor in order to directly obtain anammox granules. Results showed that the anammox UASB reactor was successfully started up by inoculating anaerobic granular sludge, with substrate capacity of 4435.2 mg/(L·d) and average ammonium and nitrite removal efficiency of 90.36% and 93.29%, respectively. During the start-up course, the granular sludge initially disintegrated and then reaggregated and turned red, suggesting the high anammox performance. Zn-Fe precipitation was observed on the surface of granules during the operation by SEM-EDS, which would impose inhibition to the anammox activity of the granules. Accordingly, it is suggested to relatively reduce the trace metals concentrations, of Fe and Zn in the conventional medium. The findings of this study are expected to be used for a shorter start-up and more stable operation of anammox system. PMID:24455691

  5. Removing nitrogen from wastewater with side stream anammox: What are the trade-offs between environmental impacts?

    NARCIS (Netherlands)

    Hauck, M.; Maalcke-Luesken, F.A.; Jetten, M.S.M.; Huijbregts, M.A.J.

    2016-01-01

    Anaerobic ammonium oxidation (anammox) is a novel way to reduce nitrogen in ammonium rich wastewater. Although aquatic eutrophication will certainly be reduced, it is unknown how other environmental impacts may change by including anammox in the treatment of wastewater. Here, life cycle assessment

  6. Behavior and fate of copper ions in an anammox granular sludge reactor and strategies for remediation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zheng-Zhe; Deng, Rui; Cheng, Ya-Fei; Zhou, Yu-Huang; Buayi, Xiemuguli [College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036 (China); Zhang, Xian; Wang, Hui-Zhong [College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); Jin, Ren-Cun, E-mail: jrczju@aliyun.com [College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036 (China)

    2015-12-30

    Highlights: • The Cu partition in an anammox UASB reactor was predicted by models. • The distribution and form dynamics of Cu in anammox reactors were tracked. • The response of the EPS to Cu(II) was characterized by 3D-EEM spectra. • The mechanism of Cu inhibition on anammox granules was updated. • The feasibilities of two novel remediation strategies were investigated. - Abstract: In this study, the behavior, distribution and form dynamics of overloaded Cu(II) in anaerobic ammonium oxidation (anammox) granular sludge reactors were investigated. The performance and physiological characteristics were tracked by continuous-flow monitoring to evaluate the long-term effects. High Cu loading (0.24 g L{sup −1} d{sup −1}) exceeded sludge bearing capacity, and precipitation dominated the removal pathway. The Cu distribution migrated from the extracellular polymeric substances-bound to the cell-associated Cu and the Cu forms shifted from the weakly bound to strongly bound fractions over time. Pearson correlation and fluorescence spectra analyses showed that the increase in protein concentrations in the EPS was a clear self-defense response to Cu(II) stress. Two remediation strategies, i.e., ethylenediamine tetraacetic acid (EDTA) washing and ultrasound-enhanced EDTA washing, weakened the equilibrium metal partition coefficient from 5.8 to 0.45 and 0.34 L mg{sup −1}SS, respectively, thereby accelerating the external diffusion of the Cu that had accumulated in the anammox granules.

  7. Behavior and fate of copper ions in an anammox granular sludge reactor and strategies for remediation

    International Nuclear Information System (INIS)

    Zhang, Zheng-Zhe; Deng, Rui; Cheng, Ya-Fei; Zhou, Yu-Huang; Buayi, Xiemuguli; Zhang, Xian; Wang, Hui-Zhong; Jin, Ren-Cun

    2015-01-01

    Highlights: • The Cu partition in an anammox UASB reactor was predicted by models. • The distribution and form dynamics of Cu in anammox reactors were tracked. • The response of the EPS to Cu(II) was characterized by 3D-EEM spectra. • The mechanism of Cu inhibition on anammox granules was updated. • The feasibilities of two novel remediation strategies were investigated. - Abstract: In this study, the behavior, distribution and form dynamics of overloaded Cu(II) in anaerobic ammonium oxidation (anammox) granular sludge reactors were investigated. The performance and physiological characteristics were tracked by continuous-flow monitoring to evaluate the long-term effects. High Cu loading (0.24 g L −1 d −1 ) exceeded sludge bearing capacity, and precipitation dominated the removal pathway. The Cu distribution migrated from the extracellular polymeric substances-bound to the cell-associated Cu and the Cu forms shifted from the weakly bound to strongly bound fractions over time. Pearson correlation and fluorescence spectra analyses showed that the increase in protein concentrations in the EPS was a clear self-defense response to Cu(II) stress. Two remediation strategies, i.e., ethylenediamine tetraacetic acid (EDTA) washing and ultrasound-enhanced EDTA washing, weakened the equilibrium metal partition coefficient from 5.8 to 0.45 and 0.34 L mg −1 SS, respectively, thereby accelerating the external diffusion of the Cu that had accumulated in the anammox granules.

  8. Hydroxylamine-dependent Anaerobic Ammonium Oxidation (Anammox) by “ Candidatus Brocadia sinica”

    KAUST Repository

    Oshiki, Mamoru

    2016-04-26

    Although metabolic pathways and associated enzymes of anaerobic ammonium oxidation (anammox) of “Ca. Kuenenia stuttgartiensis” have been studied, those of other anammox bacteria are still poorly understood. NO2- reduction to NO is considered to be the first step in the anammox metabolism of “Ca. K. stuttgartiensis”, however, “Ca. Brocadia” lacks the genes that encode canonical NO-forming nitrite reductases (NirS or NirK) in its genome, which is different from “Ca. K. stuttgartiensis”. Here, we studied the anammox metabolism of “Ca. Brocadia sinica”. 15N-tracer experiments demonstrated that “Ca. B. sinica” cells could reduce NO2- to NH2OH, instead of NO, with as yet unidentified nitrite reductase(s). Furthermore, N2H4 synthesis, downstream reaction of NO2- reduction, was investigated using a purified “Ca. B. sinica” hydrazine synthase (Hzs) and intact cells. Both the “Ca. B. sinica” Hzs and cells utilized NH2OH and NH4+, but not NO and NH4+, for N2H4 synthesis and further oxidized N2H4 to N2 gas. Taken together, the metabolic pathway of “Ca. B. sinica” is NH2OH-dependent and different from the one of “Ca. K. stuttgartiensis”, indicating metabolic diversity of anammox bacteria. This article is protected by copyright. All rights reserved.

  9. Predicting settling performance of ANAMMOX granular sludge based on fractal dimensions.

    Science.gov (United States)

    Wang, Zhiyao; Zheng, Ping

    2017-09-01

    The settling performance of ANAMMOX granular sludge determines the biomass retention in reactors, and finally determines the potential reaction capacity. In this paper, Stokes equation was modified by fractal dimensions to describe the settling performance of ANAMMOX granular sludge. A new method was developed to obtain fractal dimensions, and a fractal settling model was established for ANAMMOX granular sludge. The fractal settling model was excellent with only a small deviation of 0.8% from the experimental data. Assuming normal distribution of all Feret diameters, 88% experimental data fell into the 90% confidence interval of settling velocities. Further assuming logarithmic normal distribution, 95% experimental data fell into the 90% confidence interval. The fractal settling model is helpful for the prediction of settling velocities of granular sludge and the optimization of bioreactor performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Is metabolic rate a universal 'pacemaker' for biological processes?

    Science.gov (United States)

    Glazier, Douglas S

    2015-05-01

    A common, long-held belief is that metabolic rate drives the rates of various biological, ecological and evolutionary processes. Although this metabolic pacemaker view (as assumed by the recent, influential 'metabolic theory of ecology') may be true in at least some situations (e.g. those involving moderate temperature effects or physiological processes closely linked to metabolism, such as heartbeat and breathing rate), it suffers from several major limitations, including: (i) it is supported chiefly by indirect, correlational evidence (e.g. similarities between the body-size and temperature scaling of metabolic rate and that of other biological processes, which are not always observed) - direct, mechanistic or experimental support is scarce and much needed; (ii) it is contradicted by abundant evidence showing that various intrinsic and extrinsic factors (e.g. hormonal action and temperature changes) can dissociate the rates of metabolism, growth, development and other biological processes; (iii) there are many examples where metabolic rate appears to respond to, rather than drive the rates of various other biological processes (e.g. ontogenetic growth, food intake and locomotor activity); (iv) there are additional examples where metabolic rate appears to be unrelated to the rate of a biological process (e.g. ageing, circadian rhythms, and molecular evolution); and (v) the theoretical foundation for the metabolic pacemaker view focuses only on the energetic control of biological processes, while ignoring the importance of informational control, as mediated by various genetic, cellular, and neuroendocrine regulatory systems. I argue that a comprehensive understanding of the pace of life must include how biological activities depend on both energy and information and their environmentally sensitive interaction. This conclusion is supported by extensive evidence showing that hormones and other regulatory factors and signalling systems coordinate the processes of

  11. Concurrent Activity of Anammox and Denitrifying Bacteria in the Black Sea

    OpenAIRE

    John B. Kirkpatrick; John B. Kirkpatrick; Clara A. Fuchsman; Evgeniy eYakushev; James T. Staley; James W. Murray

    2012-01-01

    After the discovery of ANaerobic AMMonium OXidation (anammox) in the Black Sea in 2003, the role of heterotrophic denitrification as the main marine pathway for fixed N loss was questioned. A 3 part, 15 month time series investigating Black Sea nitrite reductase (nirS) mRNA transcripts at a single location was conducted in order to better understand the activity of anammox and denitrifying bacteria. Here we show that both of these groups were active, as well as being concurrent in the lower s...

  12. Concurrent activity of anammox and denitrifying bacteria in the Black Sea

    OpenAIRE

    Kirkpatrick, John B.; Fuchsman, Clara A.; Yakushev, Evgeniy; Staley, James T.; Murray, James W.

    2012-01-01

    After the discovery of ANaerobic AMMonium OXidation (anammox) in the environment, the role of heterotrophic denitrification as the main marine pathway for fixed N loss has been questioned. A 3 part, 15 month time series investigating nitrite reductase (nirS) mRNA transcripts at a single location in the Black Sea was conducted in order to better understand the activity of anammox and denitrifying bacteria. Here we show that both of these groups were active, as well as being concurrent in the l...

  13. A Comparison of EFL Raters' Essay-Rating Processes across Two Types of Rating Scales

    Science.gov (United States)

    Li, Hang; He, Lianzhen

    2015-01-01

    This study used think-aloud protocols to compare essay-rating processes across holistic and analytic rating scales in the context of China's College English Test Band 6 (CET-6). A group of 9 experienced CET-6 raters scored the same batch of 10 CET-6 essays produced in an operational CET-6 administration twice, using both the CET-6 holistic…

  14. Engineering aspects of rate-related processes in food manufacturing.

    Science.gov (United States)

    Adachi, Shuji

    2015-01-01

    Many rate-related phenomena occur in food manufacturing processes. This review addresses four of them, all of which are topics that the author has studied in order to design food manufacturing processes that are favorable from the standpoint of food engineering. They include chromatographic separation through continuous separation with a simulated moving adsorber, lipid oxidation kinetics in emulsions and microencapsulated systems, kinetic analysis and extraction in subcritical water, and water migration in pasta.

  15. Structural identification of ladderane and other membrane lipids of planctomycetes capable of anaerobic ammonium oxidation (anammox)

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Rijpstra, W.I.C.; Geenevasen, J.A.J.; Strous, M.; Jetten, M.S.M.

    2005-01-01

    The membrane lipid composition of planctomycetes capable of the anaerobic oxidation of ammonium (anammox), i.e. Candidatus ‘Brocadia anammoxidans’ and Candidatus ‘Kuenenia stuttgartiensis’, was shown to be composed mainly of so-called ladderane lipids. These lipids are comprised of three to five

  16. Using graphene oxide to enhance the activity of anammox bacteria for nitrogen removal.

    Science.gov (United States)

    Wang, Dong; Wang, Guowen; Zhang, Guoquan; Xu, Xiaochen; Yang, Fenglin

    2013-03-01

    Graphene oxide (GO) was applied in this study to enhance the activity of anaerobic ammonium oxidation (anammox) bacteria for nitrogen removal. A GO dose-dependent effect on anammox bacteria was observed through batch tests. The results showed that the activity increased as the GO dose was varied within 0.05-0.1gL(-1). A maximum 10.26% increase of anaerobic ammonium oxidizing activity was achieved at 0.1gL(-1) GO. Analysis of extracellular polymeric substances (EPS) indicated that the highest carbohydrate, protein, and total EPS contents (42.5, 125.7, and 168.2mg (g volatile suspended solids)(-1), respectively) were obtained with 0.1gL(-1) GO. Appropriate GO dose stimulated EPS production to promote the activity of anammox bacteria. Transmission electron microscopy showed the large surface area of GO benefited cell attachment. These findings proved that the application of GO was an effective approach to enhancing the activity of anammox bacteria. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Evaluation on the microbial interactions of anaerobic ammonium oxidizers and heterotrophs in Anammox biofilm

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Ruscalleda, Mael; Smets, Barth F.

    2012-01-01

    with the experimental observations of the bacterial distribution, as well as the nitrogenous transformations in batch and continuous experiments. The modeling results showed that low nitrogen surface loading resulted in a lower availability of SMP leading to low heterotrophic growth in Anammox biofilm, but high...

  18. Nitrogen Removal from Digested Black Water by One-stage Partial Nitritation and Anammox

    DEFF Research Database (Denmark)

    Vlaeminck, S.E.; Terada, Akihiko; Smets, Barth F.

    2009-01-01

    anammox activity and sufficient buffering capacity, respectively. Quantitative FISH showed that aerobic and anoxic ammonium-oxidizing bacteria (AerAOB and AnAOB) made up 43 and 8% of the biofilm, respectively. Since a part of the AerAOB was probably present in anoxic biofilm zones, their specific ammonium...

  19. High-energy, high-rate materials processing

    Science.gov (United States)

    Marcus, H. L.; Bourell, D. L.; Eliezer, Z.; Persad, C.; Weldon, W.

    1987-12-01

    The increasingly available range of pulsed-power, high energy kinetic storage devices, such as low-inductance pulse-forming networks, compulsators, and homopolar generators, is presently considered as a basis for industrial high energy/high rate (HEHR) processing to accomplish shock hardening, drilling, rapid surface alloying and melting, welding and cutting, transformation hardening, and cladding and surface melting in metallic materials. Time-temperature-transformation concepts furnish the basis for a fundamental understanding of the potential advantages of this direct pulsed power processing. Attention is given to the HEHR processing of a refractory molybdenum alloy, a nickel-base metallic glass, tungsten, titanium aluminides, and metal-matrix composites.

  20. Presence and diversity of anammox bacteria in cold hydrocarbon-rich seeps and hydrothermal vent sediments of the Guaymas Basin

    NARCIS (Netherlands)

    Russ, L.; Kartal, B.; Op den Camp, H.J.M.; Sollai, M.; Le Bruchec, J.; Caprais, J.-C.; Godfroy, A.; Sinninghe Damsté, J.S.; Jetten, M.S.M.

    2013-01-01

    Hydrothermally active sediments are highly productive, chemosynthetic areas which are characterized by the rapid turnover of particulate organic matter under extreme conditions in which ammonia is liberated. These systems might be suitable habitats for anaerobic ammonium oxidizing (anammox) bacteria

  1. Signal processing methodologies for an acoustic fetal heart rate monitor

    Science.gov (United States)

    Pretlow, Robert A., III; Stoughton, John W.

    1992-01-01

    Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use.

  2. Predicting online ratings based on the opinion spreading process

    Science.gov (United States)

    He, Xing-Sheng; Zhou, Ming-Yang; Zhuo, Zhao; Fu, Zhong-Qian; Liu, Jian-Guo

    2015-10-01

    Predicting users' online ratings is always a challenge issue and has drawn lots of attention. In this paper, we present a rating prediction method by combining the user opinion spreading process with the collaborative filtering algorithm, where user similarity is defined by measuring the amount of opinion a user transfers to another based on the primitive user-item rating matrix. The proposed method could produce a more precise rating prediction for each unrated user-item pair. In addition, we introduce a tunable parameter λ to regulate the preferential diffusion relevant to the degree of both opinion sender and receiver. The numerical results for Movielens and Netflix data sets show that this algorithm has a better accuracy than the standard user-based collaborative filtering algorithm using Cosine and Pearson correlation without increasing computational complexity. By tuning λ, our method could further boost the prediction accuracy when using Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE) as measurements. In the optimal cases, on Movielens and Netflix data sets, the corresponding algorithmic accuracy (MAE and RMSE) are improved 11.26% and 8.84%, 13.49% and 10.52% compared to the item average method, respectively.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  5. Process Measurement Deviation Analysis for Flow Rate due to Miscalibration

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eunsuk; Kim, Byung Rae; Jeong, Seog Hwan; Choi, Ji Hye; Shin, Yong Chul; Yun, Jae Hee [KEPCO Engineering and Construction Co., Deajeon (Korea, Republic of)

    2016-10-15

    An analysis was initiated to identify the root cause, and the exemption of high static line pressure correction to differential pressure (DP) transmitters was one of the major deviation factors. Also the miscalibrated DP transmitter range was identified as another major deviation factor. This paper presents considerations to be incorporated in the process flow measurement instrumentation calibration and the analysis results identified that the DP flow transmitter electrical output decreased by 3%. Thereafter, flow rate indication decreased by 1.9% resulting from the high static line pressure correction exemption and measurement range miscalibration. After re-calibration, the flow rate indication increased by 1.9%, which is consistent with the analysis result. This paper presents the brief calibration procedures for Rosemount DP flow transmitter, and analyzes possible three cases of measurement deviation including error and cause. Generally, the DP transmitter is required to be calibrated with precise process input range according to the calibration procedure provided for specific DP transmitter. Especially, in case of the DP transmitter installed in high static line pressure, it is important to correct the high static line pressure effect to avoid the inherent systematic error for Rosemount DP transmitter. Otherwise, failure to notice the correction may lead to indicating deviation from actual value.

  6. Presence and diversity of anammox bacteria in cold hydrocarbon-rich seeps and hydrothermal vent sediments of the Guaymas Basin.

    Science.gov (United States)

    Russ, Lina; Kartal, Boran; Op den Camp, Huub J M; Sollai, Martina; Le Bruchec, Julie; Caprais, Jean-Claude; Godfroy, Anne; Sinninghe Damsté, Jaap S; Jetten, Mike S M

    2013-01-01

    Hydrothermally active sediments are highly productive, chemosynthetic areas which are characterized by the rapid turnover of particulate organic matter under extreme conditions in which ammonia is liberated. These systems might be suitable habitats for anaerobic ammonium oxidizing (anammox) bacteria but this has not been investigated in detail. Here we report the diversity and abundance of anammox bacteria in sediments that seep cold hydrocarbon-rich fluids and hydrothermal vent areas of the Guaymas Basin in the Cortés Sea using the unique functional anammox marker gene, hydrazine synthase (hzsA). All clones retrieved were closely associated to the "Candidatus Scalindua" genus. Phylogenetic analysis revealed two distinct clusters of hzsA sequences (Ca. Scalindua hzsA cluster I and II). Comparison of individual sequences from both clusters showed that several of these sequences had a similarity as low as 76% on nucleotide level. Based on the analysis of this phylomarker, a very high interspecies diversity within the marine anammox group is apparent. Absolute numbers of anammox bacteria in the sediments samples were determined by amplification of a 257 bp fragment of the hszA gene in a qPCR assay. The results indicate that numbers of anammox bacteria are generally higher in cold hydrocarbon-rich sediments compared to the vent areas and the reference zone. Ladderanes, lipids unique to anammox bacteria were also detected in several of the sediment samples corroborating the hzsA analysis. Due to the high concentrations of reduced sulfur compounds and its potential impact on the cycling of nitrogen we aimed to get an indication about the key players in the oxidation of sulfide in the Guaymas Basin sediments using the alpha subunit of the adenosine-5'-phosphosulfate (APS) reductase (aprA). Amplification of the aprA gene revealed a high number of gammaproteobacterial aprA genes covering the two sulfur-oxidizing bacteria aprA lineages as well as sulfate-reducers.

  7. Metagenome analysis of a complex community reveals the metabolic blueprint of anammox bacterium ‘Candidatus Jettenia asiatica’

    Directory of Open Access Journals (Sweden)

    Ziye eHu

    2012-10-01

    Full Text Available Anammox bacteria are key players in the global nitrogen cycle and responsible for up to 50% of global nitrogen loss. Because of their cost effective application in anaerobic nitrogen removal, the anammox bacteria are widely implemented in wastewater treatment. Currently, five genera of anammox bacteria have been identified, together forming a deep branching order in the Planctomycetes-Verrucomicrobium- Chlamydiae (PVC superphylum. Members of all genera have been detected in wastewater treatment plants, but metagenomic information is not yet available for all genera. Here we report the metagenomic analysis of an enrichment dominated by ‘Candidatus Jettenia asiatica’. The whole microbial community of a granular sludge anammox reactor was sequenced using both illumina and 454 pyrosequencing. The sludge was previously shown to have a ~50% enrichment of the anammox bacterium ‘Candidatus Jettenia asiatica’ by 16S rRNA gene analysis. After de novo assembly 37,432 contigs with an average length of 571 nt were obtained. The contigs were then analyzed by BLASTx searches against the protein sequences of ‘Candidatus Kuenenia stuttgartiensis’ and a set of 25 genes essential in anammox metabolism were detected. Additionally all reads were mapped to the genome of an anammox strain KSU-1 and de novo assembly was performed again using the reads that could be mapped on KSU-1. Using this approach, a gene encoding copper-containing nitrite reductase NirK was identified in the genome, instead of cytochrome cd1-type nitrite reductase NirS that is responsible for the nitrite reduction of ‘Ca. Kuenenia stuttgartiensis’ and ‘Ca. Scalindua profunda’. Finally, the community composition was investigated through MetaCluster analysis, 16S rRNA gene analysis and read mapping, which showed the presence of other important community members such as aerobic ammonia-oxidizing bacteria, methane producing microorganisms and denitrifying methanotroph 'Ca

  8. [Simultaneous removal of carbon and nitrogen from organic-rich wastewater with Anammox].

    Science.gov (United States)

    Chen, Chongjun; Zhu, Weijing; Huang, Xiaoxiao; Wu, Weixiang

    2014-12-01

    In order to simultaneously remove carbon and nitrogen from organic-rich wastewater, we used an up-flow anaerobic sludge bed/blanket (UASB) reactor that was started up with anammox with high concentration of carbon and nitrogen by gradually raising the organic loading of influent. We optimized the removal of nitrogen and carbon when the chemical oxygen demand (COD) concentration varied from 172 to 620 mg/L. During the entire experiment, the ammonium and total nitrogen removal efficiency was higher than 85%, while the average COD removal efficiency was 56.6%. The high concentration of organic matter did not restrain the activity of anammox bacteria. Based on polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and tapping sequencing analyses, the Planctomycete, Proteobacteria, Chloroflexi, Chlorobi bacteria are detected in the UASB reactor, which indicated complex removal pathway of carbon and nitrogen coexisted in the reactor. However, a part of Planctomycete which referred to anammox bacteria could tolerate a high content of organic carbon, and it provided help for high performance of nitrogen removal in UASB reactor.

  9. Frictional processes of bimaterial interfaces at seismic slip rates.

    Science.gov (United States)

    Passelegue, F. X.; Fabbri, O.; Leclère, H.; Spagnuolo, E.; Di Toro, G.

    2017-12-01

    Large subduction earthquakes ruptures propagate from crustal rock toward the sea floor along frictional interfaces of different lythologies. Up to now, frictional processes of rocks were mainly investigated along single material experimental faults. Here, we present the results of high velocity friction experiments coupled with high frequency acoustic monitoring system on biomaterial interfaces including gabbro, pyroxenite and serpentinized peridotite (>95%), following a recent field investigation highlighting bimaterial contacts in the Corsica ophiolitic nappe. We first studied the frictional processes of single materials which result in a mechanical behaviour comparable to previous studies. Both gabbro and pyroxenite exhibit two weakening stages. The first one corresponds to flash heating and the second stage occurs concomitantly with complete melting of the interface. In the case of serpentinite, only one weakening stage is observed, after a weakening slip distance of only few centimeters. We then conducted bimaterial experiments. The two couples tested were gabbro/pyroxenite and gabbro/serpentinite, as observed along natural fault zones (Corsica, France). In the case of gabbro/serpentinite, we observe that frictional processes are controlled by serpentinite. Mechanical curves replicate the behaviour of single serpentinite friction experiments. We observe that few melting occurs, and that the product of experiments consists in fine grained cataclasite, as observed in the field. The case of gabbro/pyroxenite is more complicated. The first weakening is controlled by the lithology of the sample installed on the static part of the rotary apparatus. However, the second weakening is controlled by the gabbro and mechanical curves are identical than those obtained in the case of single gabbro experiments. Supported by microstructural analysis and acoustic activity, our results suggest that frictional processes of bimaterial interfaces are controlled by the material

  10. Global optimization numerical strategies for rate-independent processes

    Czech Academy of Sciences Publication Activity Database

    Benešová, Barbora

    2011-01-01

    Roč. 50, č. 2 (2011), s. 197-220 ISSN 0925-5001 R&D Projects: GA ČR GAP201/10/0357 Grant - others:GA MŠk(CZ) LC06052 Program:LC Institutional research plan: CEZ:AV0Z20760514 Keywords : rate-independent processes * numerical global optimization * energy estimates based algorithm Subject RIV: BA - General Mathematics Impact factor: 1.196, year: 2011 http://math.hnue.edu.vn/portal/rss.viewpage.php?id=0000037780&ap=L3BvcnRhbC9ncmFiYmVyLnBocD9jYXRpZD0xMDEyJnBhZ2U9Mg==

  11. Digital Signal Processing For Low Bit Rate TV Image Codecs

    Science.gov (United States)

    Rao, K. R.

    1987-06-01

    In view of the 56 KBPS digital switched network services and the ISDN, low bit rate codecs for providing real time full motion color video are under various stages of development. Some companies have already brought the codecs into the market. They are being used by industry and some Federal Agencies for video teleconferencing. In general, these codecs have various features such as multiplexing audio and data, high resolution graphics, encryption, error detection and correction, self diagnostics, freezeframe, split video, text overlay etc. To transmit the original color video on a 56 KBPS network requires bit rate reduction of the order of 1400:1. Such a large scale bandwidth compression can be realized only by implementing a number of sophisticated,digital signal processing techniques. This paper provides an overview of such techniques and outlines the newer concepts that are being investigated. Before resorting to the data compression techniques, various preprocessing operations such as noise filtering, composite-component transformation and horizontal and vertical blanking interval removal are to be implemented. Invariably spatio-temporal subsampling is achieved by appropriate filtering. Transform and/or prediction coupled with motion estimation and strengthened by adaptive features are some of the tools in the arsenal of the data reduction methods. Other essential blocks in the system are quantizer, bit allocation, buffer, multiplexer, channel coding etc.

  12. Treating landfill leachate using passive aeration trickling filters; effects of leachate characteristics and temperature on rates and process dynamics.

    Science.gov (United States)

    Matthews, Richard; Winson, Michael; Scullion, John

    2009-04-01

    Biological ammoniacal-nitrogen (NH(4)(+)-N) and organic carbon (TOC) treatment was investigated in replicated mesoscale attached microbial film trickling filters, treating strong and weak strength landfill leachates in batch mode at temperatures of 3, 10, 15 and 30 degrees C. Comparing leachates, rates of NH(4)(+)-N reduction (0.126-0.159 g m(-2) d(-1)) were predominantly unaffected by leachate characteristics; there were significant differences in TOC rates (0.072-0.194 g m(-2) d(-1)) but no trend relating to leachate strength. Rates of total oxidised nitrogen (TON) accumulation (0.012-0.144 g m(-2) d(-1)) were slower for strong leachates. Comparing temperatures, treatment rates varied between 0.029-0.319 g NH(4)(+)-N m(-2) d(-1) and 0.033-0.251 g C m(-2) d(-1) generally increasing with rising temperatures; rates at 3 degrees C were 9 and 13% of those at 30 degrees C for NH(4)(+)-N and TOC respectively. For the weak leachates (NH(4)(+)-N<140 mg l(-1)) complete oxidation of NH(4)(+)-N was achieved. For the strong leachates (NH(4)(+)-N 883-1150 mg l(-1)) a biphasic treatment response resulted in NH(4)(+)-N removal efficiencies of between 68 and 88% and for one leachate no direct transformation of NH(4)(+)-N to TON in bulk leachate. The temporal decoupling of NH(4)(+)-N oxidation and TON accumulation in this leachate could not be fully explained by denitrification, volatilisation or anammox, suggesting temporary storage of N within the treatment system. This study demonstrates that passive aeration trickling filters can treat well-buffered high NH(4)(+)-N strength landfill leachates under a range of temperatures and that leachate strength has no effect on initial NH(4)(+)-N treatment rates. Whether this approach is a practicable option depends on a range of site specific factors.

  13. Combination of upflow anaerobic sludge blanket (UASB) reactor and partial nitritation/anammox moving bed biofilm reactor (MBBR) for municipal wastewater treatment.

    Science.gov (United States)

    Malovanyy, Andriy; Yang, Jingjing; Trela, Jozef; Plaza, Elzbieta

    2015-03-01

    In this study the combination of an upflow anaerobic sludge blanket (UASB) reactor and a deammonification moving bed biofilm reactor (MBBR) for mainstream wastewater treatment was tested. The competition between aerobic ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) was studied during a 5months period of transition from reject water to mainstream wastewater followed by a 16months period of mainstream wastewater treatment. The decrease of influent ammonium concentration led to a wash-out of suspended biomass which had a major contribution to nitrite production. Influence of a dissolved oxygen concentration and a transient anoxia mechanism of NOB suppression were studied. It was shown that anoxic phase duration has no effect on NOB metabolism recovery and oxygen diffusion rather than affinities of AOB and NOB to oxygen determine the rate of nitrogen conversion in a biofilm system. Anammox activity remained on the level comparable to reject water treatment systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Rate process analysis of thermal damage in cartilage

    International Nuclear Information System (INIS)

    Diaz, Sergio H; Nelson, J Stuart; Wong, Brian J F

    2003-01-01

    Cartilage laser thermoforming (CLT) is a new surgical procedure that allows in situ treatment of deformities in the head and neck with less morbidity than traditional approaches. While some animal and human studies have shown promising results, the clinical feasibility of CLT depends on preservation of chondrocyte viability, which has not been extensively studied. The present paper characterizes cellular damage due to heat in rabbit nasal cartilage. Damage was modelled as a first order rate process for which two experimentally derived coefficients, A=1.2x10 70 s -1 and E a =4.5x10 5 J mole -1 , were determined by quantifying the decrease in concentration of healthy chondrocytes in tissue samples as a function of exposure time to constant-temperature water baths. After immersion, chondrocytes were enzymatically isolated from the matrix and stained with a two-component fluorescent dye. The dye binds nuclear DNA differentially depending upon chondrocyte viability. A flow cytometer was used to detect differential cell fluorescence to determine the percentage of live and dead cells in each sample. As a result, a damage kinetic model was obtained that can be used to predict the onset, extent and severity of cellular injury to thermal exposure

  15. Diversity of total and functional microbiome of anammox reactors fed with complex and synthetic nitrogen-rich wastewaters

    DEFF Research Database (Denmark)

    Gülay, Arda; Pellicer i Nàcher, Carles; Mutlu, Ayten Gizem

    implementations treating complex nitrogen-rich wastewaters and 14 were lab-scale implementations treating synthetic wastewaters. We found that nitritation/anammox bioreactors treating complex nitrogen-rich wastewaters were more diverse in terms of total microbial diversity but less diverse at anammox functional...... diversity than the bioreactors treating synthetic wastewaters inferred from observed OTUs0.03, Chao1, Shannon index and Phylogenetic distance calculations. Differences in total microbial diversity agreed with the ecological theory concerning the positive correlation between substrate complexity...... weighted UniFrac algorithm explained 29% of the variance where the bioreactor samples of complex nitrogen-rich wastewater feeding was clearly separated from the bioreactor samples of synthetic feeding. Here we examined and compared for the first time microbial diversity of nitritation-anammox reactors...

  16. PREFACE: International Workshop on Multi-Rate Processes and Hysteresis

    Science.gov (United States)

    Mortell, Michael P.; O'Malley, Robert E.; Pokrovskii, Alexei; Rachinskii, Dmitrii; Sobolev, Vladimir A.

    2008-07-01

    We are interested in singular perturbation problems and hysteresis as common strongly nonlinear phenomena that occur in many industrial, physical and economic systems. The wording `strongly nonlinear' means that linearization will not encapsulate the observed phenomena. Often these two types of phenomena are manifested for different stages of the same or similar processes. A number of fundamental hysteresis models can be considered as limit cases of time relaxation processes, or admit an approximation by a differential equation which is singular with respect to a particular parameter. However, the amount of interaction between practitioners of theories of systems with time relaxation and systems with hysteresis (and between the `relaxation' and `hysteresis' research communities) is still low, and cross-fertilization is small. In recent years Ireland has become a home for a series of prestigious International Workshops in Singular Perturbations and Hysteresis: International Workshop on Multi-rate Processes and Hysteresis (University College Cork, Ireland, 3-8 April 2006). Proceedings are published in Journal of Physics: Conference Series, volume 55. See further information at http://euclid.ucc.ie/murphys2008.htm International Workshop on Hysteresis and Multi-scale Asymptotics (University College Cork, Ireland, 17-21 March 2004). Proceedings are published in Journal of Physics: Conference Series, volume 22. See further information at http://euclid.ucc.ie/murphys2006.htm International Workshop on Relaxation Oscillations and Hysteresis (University College Cork, Ireland, 1-6 April 2002). The related collection of invited lectures, was published as a volume Singular Perturbations and Hysteresis, SIAM, Philadelphia, 2005. See further information at http://euclid.ucc.ie/hamsa2004.htm International Workshop on Geometrical Methods of Nonlinear Analysis and Semiconductor Laser Dynamics (University College Cork, Ireland, 5-5 April 2001). A collection of invited papers has been

  17. A microdiversity study of anammox bacteria reveals a novel Candidatus Scalindua phylotype in marine oxygen minimum zones

    Digital Repository Service at National Institute of Oceanography (India)

    Woebken, D.; Lam, P.; Kuypers, M.M.M.; Naqvi, S.W.A.; Kartal, B.; Strous, M.; Jetten, M.S.M.; Fuchs, B.M.; Amann, R.

    periods of starvation. FISH with probes targeting the ITS region (Oerther et al., 2000) has already been applied for anammox bacteria (Schmid et al., 2001). Hence, in addition to anammox bacterial abundance, the level of denovo rRNA synthesis as a central..., the cruise leaders V. Brüchert (Namibia) and G. Lavik and D. Gutiérrez (Peru) for organizing the cruises. Furthermore, the excellent technical assistance of Judith Ufkes and Christoph Walcher is acknowledged. The work was supported by the Deutsche...

  18. PREFACE: International Workshop on Multi-Rate processes and Hysterisis

    Science.gov (United States)

    Mortell, Michael P.; O'Malley, Robert E.; Pokrovskii, Alexei V.; Sobolev, Vladimir A.

    2006-12-01

    with an emphasis on hysteresis and singular perturbations; to learn and to share modern techniques in areas of common interest. The `International Workshop on Multi-Rate Processes and Hysteresis' (University College Cork, Ireland, April 3-8, 2006) brought together more than 50 scientists, actively researching in the areas of dynamical systems with hysteresis and singular perturbations, to analyze these phenomena that occur in many industrial, physical and economic systems. The Workshop has been sponsored by the University College Cork (UCC), the Boole Centre for Research in Informatics, UCC, Cork, the School of Mathematical Sciences UCC, Cork, Science Foundation Ireland and the Irish Mathematical Society. The supportive affiliation of the UK and Republic of Ireland SIAM Section is gratefully acknowledged. The Editors and the Organizers of the Workshop wish to place on record their sincere gratitude to Mr Andrew Zhezherun of University College Cork for both the assistance which he provided to all the presenters at the Workshop, and for the careful formatting of all the manuscripts prior to their being forwarded to the Publisher. More information about the Workshop can be found at http://euclid.ucc.ie/murphys2006.htm Michael P Mortell, Robert E O'Malley, Alexei Pokrovskii and Vladimir Sobolev Editors From left to right: M P Mortell, V Sobolev, R E O'Malley and A Pokrovskii.

  19. STANFORD IN-SITU HIGH RATE YBCO PROCESS: TRANSFER TO METAL TAPES AND PROCESS SCALE UP

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm R. Beasley; Robert H.Hammond

    2009-04-14

    Executive Summary The materials science understanding of high rate low cost processes for Coated Conductor will benefit the application to power utilities for low loss energy transportation and power generation as well for DOD applications. The research in this program investigated several materials processing approaches that are new and original, and are not being investigated elsewhere. This work added to the understanding of the material science of high rate PVD growth of HTSC YBCO assisted by a liquid phase. A new process discovered uses amorphous glassy precursors which can be made at high rate under flexible conditions of temperature and oxygen, and later brought to conditions of oxygen partial pressure and temperature for rapid conversion to YBCO superconductor. Good critical current densities were found, but further effort is needed to optimize the vortex pinning using known artificial inclusions. A new discovery of the physics and materials science of vortex pinning in the HTSC system using Sm in place of Y came at growth at unusually low oxygen pressure resulting in clusters of a low or non superconducting phase within the nominal high temperature phase. The driving force for this during growth is new physics, perhaps due to the low oxygen. This has the potential for high current in large magnetic fields at low cost, applicable to motors, generators and transformers. The technical demands of this project were the motivation for the development of instrumentation that could be essential to eventual process scale up. These include atomic absorption based on tunable diode lasers for remote monitoring and control of evaporation sources (developed under DARPA support), and the utility of Fourier Transform Infrared Reflectivity (FTIR) for aid in the synthesis of complex thin film materials (purchased by a DURIP-AFOSR grant).

  20. Stellar neutron capture rates and the s process

    Directory of Open Access Journals (Sweden)

    Käppeler F.

    2012-02-01

    Full Text Available Neutron reactions are responsible for the formation of the elements heavier than iron. The corresponding scenarios relate to helium burning in Red Giant stars (s process and to supernova explosions (r and p processes. The s process, which operates in or near the valley of β-stability, has produced about half of the elemental abundances between Fe and Bi. Accurate (n, γ cross sections are the essential input for s process studies, because they determine the abundances produced by that process. Following a brief summary of the neutron capture processes, the focus will be set on the s process in massive stars, where the role of reliable cross section information is particularly important. Eventually, the intriguing aspects of the origin of 60Fe will be addressed. Attempts to determine the stellar cross section of that isotope are pushing experimental possibilities to their limits and present a pertinent challenge for future facilities.

  1. Nitrous oxide production pathways in a partial nitritation-anammox reactor: Isotopic evidence for nitrous oxide production associated anaerobic ammonium oxidation?

    Science.gov (United States)

    Wunderlin, P.; Harris, E. J.; Joss, A.; Emmenegger, L.; Kipf, M.; Mohn, J.; Siegrist, H.

    2014-12-01

    Nitrous oxide (N2O) is a strong greenhouse gas and a major sink for stratospheric ozone. In biological wastewater treatment N2O can be produced via several pathways. This study investigates the dynamics of N2O emissions from a nitritation-anammox reactor, and links its interpretation to the nitrogen and oxygen isotopic signature of the emitted N2O. A 400-litre single-stage nitritation-anammox reactor was operated and continuously fed with digester liquid. The isotopic composition of N2O emissions was monitored online with quantum cascade laser absorption spectroscopy (QCLAS; Aerodyne Research, Inc.; Waechter et al., 2008). Dissolved ammonium and nitrate were monitored online (ISEmax, Endress + Hauser), while nitrite was measured with test strips (Nitrite-test 0-24mgN/l, Merck). Table 1. Summary of experiments conducted to understand N2O emissions Experimental conditions O2[mgO2/L] NO2-[mgN/L] NH4+[mgN/L] N2O/NH4+[%] Normal operation in the reactor. Our data reveal that N2O emissions increased when reactor operation was not ideal, for example when dissolved oxygen was too high (Table 1). SP measurements confirmed that these N2O peaks were due to enhanced nitrifier denitrification, generally related to nitrite build-up in the reactor (Figure 1; Table 1). Overall, process control via online N2O monitoring was confirmed to be an ideal method to detect imbalances in reactor operation and regulate aeration, to ensure optimal reactor conditions and minimise N2O emissions. ReferencesWaechter H. et al. (2008) Optics Express, 16: 9239-9244. Wunderlin, P et al. (2013) Environmental Science & Technology 47: 1339-1348.

  2. Mean level signal crossing rate for an arbitrary stochastic process

    DEFF Research Database (Denmark)

    Yura, Harold T.; Hanson, Steen Grüner

    2010-01-01

    The issue of the mean signal level crossing rate for various probability density functions with primary relevance for optics is discussed based on a new analytical method. This method relies on a unique transformation that transforms the probability distribution under investigation into a normal...... probability distribution, for which the distribution of mean level crossings is known. In general, the analytical results for the mean level crossing rate are supported and confirmed by numerical simulations. In particular, we illustrate the present method by presenting analytic expressions for the mean level...... crossing rate for various probability distributions, including ones that previously were unavailable, such as the uniform, the so-called gamma-gamma, and the Rice–Nakagami distribution. However, in a limited number of cases the present results differ somewhat from the result reported in the literature...

  3. Rate Theory for Correlated Processes: Double Jumps in Adatom Diffusion

    DEFF Research Database (Denmark)

    Jacobsen, J.; Jacobsen, Karsten Wedel; Sethna, J.

    1997-01-01

    We study the rate of activated motion over multiple barriers, in particular the correlated double jump of an adatom diffusing on a missing-row reconstructed platinum (110) surface. We develop a transition path theory, showing that the activation energy is given by the minimum-energy trajectory...... which succeeds in the double jump. We explicitly calculate this trajectory within an effective-medium molecular dynamics simulation. A cusp in the acceptance region leads to a root T prefactor for the activated rate of double jumps. Theory and numerical results agree....

  4. On the rate of convergence of some stochastic processes

    NARCIS (Netherlands)

    Kern, Walter

    1989-01-01

    We present a general technique for obtaining bounds on the deviation of the optimal value of some stochastic combinatorial problems from their mean. As a particular application, we prove an exponential rate of convergence for the length of a shortest path through n random points in the unit square.

  5. Biological Nitrogen Removal in a Photosequencing Batch Reactor with an Algal-Nitrifying Bacterial Consortium and Anammox Granules

    NARCIS (Netherlands)

    Manser, Nathan D.; Wang, Meng; Ergas, Sarina J.; Mihelcic, James R.; Mulder, Arnold; van de Vossenberg, Jack; van Lier, J.B.; Van Der Steen, Peter

    2016-01-01

    This study demonstrates the feasibility of combining microalgae, ammonia-oxidizing bacteria (AOB), and Anammox in a photosequencing batch reactor. Alternating light and dark periods were applied to achieve biological nitrogen removal without mechanical aeration or external electron donor

  6. Development of Electroactive and Anaerobic Ammonium-Oxidizing (Anammox Biofilms from Digestate in Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Enea Gino Di Domenico

    2015-01-01

    Full Text Available Microbial Fuel cells (MFCs have been proposed for nutrient removal and energy recovery from different wastes. In this study the anaerobic digestate was used to feed H-type MFC reactors, one with a graphite anode preconditioned with Geobacter sulfurreducens and the other with an unconditioned graphite anode. The data demonstrate that the digestate acts as a carbon source, and even in the absence of anode preconditioning, electroactive bacteria colonise the anodic chamber, producing a maximum power density of 172.2 mW/m2. The carbon content was also reduced by up to 60%, while anaerobic ammonium oxidation (anammox bacteria, which were found in the anodic compartment of the reactors, contributed to nitrogen removal from the digestate. Overall, these results demonstrate that MFCs can be used to recover anammox bacteria from natural sources, and it may represent a promising bioremediation unit in anaerobic digestor plants for the simultaneous nitrogen removal and electricity generation using digestate as substrate.

  7. Presence and diversity of anammox bacteria in cold hydrocarbon-rich seeps and hydrothermal vent sediments of the Guaymas Basin

    Directory of Open Access Journals (Sweden)

    Lina eRuss

    2013-08-01

    Full Text Available Hydrothermally active sediments are highly productive, chemosynthetic areas which are characterized by the rapid turnover of particulate organic matter under extreme conditions in which ammonia is liberated. These systems might be suitable habitats for anaerobic ammonium oxidizing (anammox bacteria but this has not been investigated in detail. Here we report the diversity and abundance of anammox bacteria in sediments that seep cold hydrocarbon-rich fluids and hydrothermal vent areas of the Guaymas Basin in the Cortés Sea using the unique functional anammox marker gene, hydrazine synthase (hzsA. All clones retrieved were closely associated to the ‘Candidatus Scalindua’ genus. Phylogenetic analysis revealed two distinct clusters of hzsA sequences (Ca. Scalindua hzsA cluster I and II. Comparison of individual sequences from both clusters showed that several of these sequences had a similarity as low as 76% on nucleotide level. Based on the analysis of this phylomarker, a very high interspecies diversity within the marine anammox group is apparent. Absolute numbers of anammox bacteria in the sediments samples were determined by amplification of a 257 bp fragment of the hszA gene in a qPCR assay. The results indicate that numbers of anammox bacteria are generally higher in cold hydrocarbon-rich sediments compared to the vent areas and the reference zone. Ladderanes, lipids unique to anammox bacteria were also detected in several of the sediment samples corroborating the hzsA analysis. Due to the high concentrations of reduced sulfur compounds and its potential impact on the cycling of nitrogen we aimed to get an indication about the key players in the oxidation of sulfide in the Guaymas Basin sediments using the alpha subunit of the adenosine-5’-phosphosulfate (APS reductase (aprA. Amplification of the aprA gene revealed a high number of gammaproteobacterial aprA genes covering the two sulfur-oxidizing bacteria aprA lineages as well as

  8. Rates and regulation of nitrogen cycling in seasonally hypoxic sediments during winter (Boknis Eck, SW Baltic Sea): Sensitivity to environmental variables

    Science.gov (United States)

    Dale, A. W.; Sommer, S.; Bohlen, L.; Treude, T.; Bertics, V. J.; Bange, H. W.; Pfannkuche, O.; Schorp, T.; Mattsdotter, M.; Wallmann, K.

    2011-11-01

    This study investigates the biogeochemical processes that control the benthic fluxes of dissolved nitrogen (N) species in Boknis Eck - a 28 m deep site in the Eckernförde Bay (southwestern Baltic Sea). Bottom water oxygen concentrations (O 2-BW) fluctuate greatly over the year at Boknis Eck, being well-oxygenated in winter and experiencing severe bottom water hypoxia and even anoxia in late summer. The present communication addresses the winter situation (February 2010). Fluxes of ammonium (NH 4+), nitrate (NO 3-) and nitrite (NO 2-) were simulated using a benthic model that accounted for transport and biogeochemical reactions and constrained with ex situ flux measurements and sediment geochemical analysis. The sediments were a net sink for NO 3- (-0.35 mmol m -2 d -1 of NO 3-), of which 75% was ascribed to dissimilatory reduction of nitrate to ammonium (DNRA) by sulfide oxidizing bacteria, and 25% to NO 3- reduction to NO 2- by denitrifying microorganisms. NH 4+ fluxes were high (1.74 mmol m -2 d -1 of NH 4+), mainly due to the degradation of organic nitrogen, and directed out of the sediment. NO 2- fluxes were negligible. The sediments in Boknis Eck are, therefore, a net source of dissolved inorganic nitrogen (DIN = NO 3- + NO 2- + NH 4+) during winter. This is in large part due to bioirrigation, which accounts for 76% of the benthic efflux of NH 4+, thus reducing the capacity for nitrification of NH 4+. The combined rate of fixed N loss by denitrification and anammox was estimated at 0.08 mmol m -2 d -1 of N 2, which is at the lower end of previously reported values. A systematic sensitivity analysis revealed that denitrification and anammox respond strongly and positively to the concentration of NO 3- in the bottom water (NO 3-BW). Higher O 2-BW decreases DNRA and denitrification but stimulates both anammox and the contribution of anammox to total N 2 production (%R amx). A complete mechanistic explanation of these findings is provided. Our analysis indicates

  9. Computer simulated rate processes in copper vapor lasers

    Science.gov (United States)

    Harstad, K. C.

    1980-01-01

    A computer model for metal vapor lasers has been developed which places emphasis on the change of excited state populations of the lasant through inelastic collisions and radiative interaction. Also included are an energy equation for the pumping electrons and rate equations for laser photon densities. Presented are results of calculations for copper vapor with a neon buffer over a range of conditions. General agreement with experiments was obtained.

  10. Fast optical signal processing in high bit rate OTDM systems

    DEFF Research Database (Denmark)

    Poulsen, Henrik Nørskov; Jepsen, Kim Stokholm; Clausen, Anders

    1998-01-01

    As all-optical signal processing is maturing, optical time division multiplexing (OTDM) has also gained interest for simple networking in high capacity backbone networks. As an example of a network scenario we show an OTDM bus interconnecting another OTDM bus, a single high capacity user represen...

  11. High Metal Removal Rate Process for Machining Difficult Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bates, Robert; McConnell, Elizabeth

    2016-06-29

    Machining methods across many industries generally require multiple operations to machine and process advanced materials, features with micron precision, and complex shapes. The resulting multiple machining platforms can significantly affect manufacturing cycle time and the precision of the final parts, with a resultant increase in cost and energy consumption. Ultrafast lasers represent a transformative and disruptive technology that removes material with micron precision and in a single step manufacturing process. Such precision results from athermal ablation without modification or damage to the remaining material which is the key differentiator between ultrafast laser technologies and traditional laser technologies or mechanical processes. Athermal ablation without modification or damage to the material eliminates post-processing or multiple manufacturing steps. Combined with the appropriate technology to control the motion of the work piece, ultrafast lasers are excellent candidates to provide breakthrough machining capability for difficult-to-machine materials. At the project onset in early 2012, the project team recognized that substantial effort was necessary to improve the application of ultrafast laser and precise motion control technologies (for micromachining difficult-to-machine materials) to further the aggregate throughput and yield improvements over conventional machining methods. The project described in this report advanced these leading-edge technologies thru the development and verification of two platforms: a hybrid enhanced laser chassis and a multi-application testbed.

  12. Prediction of Mass Flow Rate in Supersonic Natural Gas Processing

    Directory of Open Access Journals (Sweden)

    Wen Chuang

    2015-11-01

    Full Text Available The mass flow rate of natural gas through the supersonic separator was numerically calculated by various cubic equations of state. The numerical results show that the compressibility factor and specific heat ratio for ideal gas law diverge remarkably from real gas models at a high inlet pressure. Simultaneously, the deviation of mass flow calculated by the ideal and real gas models reaches over 10 %. The difference increases with the lower of the inlet temperature regardless of the inlet pressure. A higher back pressure results in an earlier location of the shock wave. The pressure ratio of 0.72 is the first threshold to get the separator work normally. The second threshold is 0.95, in which case the whole flow is subsonic and cannot reach the choked state. The shock position moves upstream with the real gas model compared to the ideal gas law in the cyclonic separation section.

  13. Breakdown processes in wire chambers, prevention and rate capability

    International Nuclear Information System (INIS)

    Atac, M.

    1983-01-01

    Breakdowns were optically and electronically observed in drift tubes and drift chambers. They occur at a critical gain for given intensity in a gas mixture when ultraviolet photons are not completely quenched. It was observed that the breakdowns depended critically on average current for a given gas mixture independent of the size of the drift tubes used. Using 4.6% ethyl alcohol vapor mixed into 50/50 argon ethane gas, breakdown are eliminated up to 7 /sub μ/A average current drawn by pulses on a 1 cm section of an anode wire under an intense source. Pulses with an avalanche size of 10 6 electron rates above 10 6 pulses per centimeter per wire may be obtained with the elimination of breakdowns

  14. Exchange Rate Exposure Management: The Benchmarking Process of Industrial Companies

    DEFF Research Database (Denmark)

    Aabo, Tom

    Based on a cross-case study of Danish industrial companies the paper analyzes the benchmarking of the optimal hedging strategy. A stock market approach is pursued but a serious question mark is put on the validity of the obtained information seen from a corporate value-adding point of view...... of practices and strategies that have been established in each company fairly independently over time. The paper argues that hedge benchmarks are useful in their creation process (by forcing a comprehensive analysis) as well as in their final status (by the establishment of a consistent hedging strategy....... The conducted interviews show that empirical reasons behind actual hedging strategies vary considerably - some in accordance with mainstream finance theory, some resting on asymmetric information. The diversity of attitudes seems to be partly a result of different competitive environments, partly a result...

  15. The first report of a microdiverse anammox bacteria community in waters of Colombian Pacific, a transition area between prominent oxygen minimum zones of the eastern tropical Pacific.

    Science.gov (United States)

    Castro-González, M; Molina, V; Rodríguez-Rubio, E; Ulloa, O

    2014-12-01

    Anaerobic ammonium oxidizers contribute to the removal of fixed nitrogen in oxygen-deficient marine ecosystems such as oxygen minimum zones (OMZ). Here we surveyed for the first time the occurrence and diversity of anammox bacteria in the Colombian Pacific, a transition area between the prominent South and North Pacific OMZs. Anammox bacteria were detected in the coastal and oceanic areas of the Colombian Pacific in low oxygen (ammonium (anammox bacteria were rich [∼ 7 operational taxonomic units (OTUs), 98% cut-off) and microdiverse (Shannon index H′ Sea and Black Sea. Anammox bacteria-like sequences from the Colombian Pacific were grouped together with sequences retrieved from the distinct OMZ's marine subclusters (Peru, Northern Chile and Arabian Sea) within Candidatus ‘Scalindua spp’. Moreover, some anammox bacteria OTUs shared a low similarity with environmental phylotypes (86–94%). Our results indicated that a microdiverse anammox community inhabits the Colombian Pacific, generating new questions about the ecological and biogeochemical differences influencing its community structure.

  16. Characterization of Anammox Hydrazine Dehydrogenase, a Key N2-producing Enzyme in the Global Nitrogen Cycle.

    Science.gov (United States)

    Maalcke, Wouter J; Reimann, Joachim; de Vries, Simon; Butt, Julea N; Dietl, Andreas; Kip, Nardy; Mersdorf, Ulrike; Barends, Thomas R M; Jetten, Mike S M; Keltjens, Jan T; Kartal, Boran

    2016-08-12

    Anaerobic ammonium-oxidizing (anammox) bacteria derive their energy for growth from the oxidation of ammonium with nitrite as the electron acceptor. N2, the end product of this metabolism, is produced from the oxidation of the intermediate, hydrazine (N2H4). Previously, we identified N2-producing hydrazine dehydrogenase (KsHDH) from the anammox organism Kuenenia stuttgartiensis as the gene product of kustc0694 and determined some of its catalytic properties. In the genome of K. stuttgartiensis, kustc0694 is one of 10 paralogs related to octaheme hydroxylamine (NH2OH) oxidoreductase (HAO). Here, we characterized KsHDH as a covalently cross-linked homotrimeric octaheme protein as found for HAO and HAO-related hydroxylamine-oxidizing enzyme kustc1061 from K. stuttgartiensis Interestingly, the HDH trimers formed octamers in solution, each octamer harboring an amazing 192 c-type heme moieties. Whereas HAO and kustc1061 are capable of hydrazine oxidation as well, KsHDH was highly specific for this activity. To understand this specificity, we performed detailed amino acid sequence analyses and investigated the catalytic and spectroscopic (electronic absorbance, EPR) properties of KsHDH in comparison with the well defined HAO and kustc1061. We conclude that HDH specificity is most likely derived from structural changes around the catalytic heme 4 (P460) and of the electron-wiring circuit comprising seven His/His-ligated c-type hemes in each subunit. These nuances make HDH a globally prominent N2-producing enzyme, next to nitrous oxide (N2O) reductase from denitrifying microorganisms. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Enhancement of the rate of radiative processes in the field of a magnetic monopole

    International Nuclear Information System (INIS)

    Barut, A.O.; Shnir, Ya.M.; Knyazev, M.A.; Tolkachev, E.A.

    1993-07-01

    The spontaneous emission rate for the bound system charge-dyon is calculated. It is shown that the magnetic monopole fields leads to the significant increase of the rate of radiative processes. (author). 14 refs

  18. Review of quantitative procedures to obtain earthquake occurrence rates from rates of geological processes: application to the eastern United States

    International Nuclear Information System (INIS)

    Anderson, J.G.

    1987-01-01

    This paper reviews the physical and experimental bases for a quantitative relationship between earthquake occurrence rates and geological deformation rates. In brief, these relationships are well founded on mathematical statement of the elastic rebound theory, and well supported by observations. A quantitative test for the adequacy of a historical catalog, motivated from results of Smith (1976), is presented. The role of aseismic creep, the width of the seismogenic zone, the shape of the earthquake magnitude - occurrence rate curve (including maximum earthquake), and the limitations of geological observations to define deformation rates are the most importance sources of uncertainty in the process. Anderson (1986) presented evidence consistent with the hypothesis that erosion and deposition rates might control the seismic strain rate, or might determine the lower bound for the seismic strain rate. This is one of the few hypotheses that allow for prediction of earthquake rates in the eastern US. This hypothesis might imply that earthquakes are without significance for tectonic deformation of the region and the widespread lack of surface faulting. It also might give a physical basis for estimates of the maximum earthquake, and allow for a (lower bound?) estimate of seismic hazard which is independent of the historical record of earthquakes

  19. The determinants of exchange rates and the movements of EUR/RON exchange rate via non-linear stochastic processes

    Directory of Open Access Journals (Sweden)

    Petrică Andreea-Cristina

    2017-07-01

    Full Text Available Modeling exchange rate volatility became an important topic for research debate starting with 1973, when many countries switched to floating exchange rate system. In this paper, we focus on the EUR/RON exchange rate both as an economic measure and present the implied economic links, and also as a financial investment and analyze its movements and fluctuations through two volatility stochastic processes: the Standard Generalized Autoregressive Conditionally Heteroscedastic Model (GARCH and the Exponential Generalized Autoregressive Conditionally Heteroscedastic Model (EGARCH. The objective of the conditional variance processes is to capture dependency in the return series of the EUR/RON exchange rate. On this account, analyzing exchange rates could be seen as the input for economic decisions regarding Romanian macroeconomics - the exchange rates being influenced by many factors such as: interest rates, inflation, trading relationships with other countries (imports and exports, or investments - portfolio optimization, risk management, asset pricing. Therefore, we talk about political stability and economic performance of a country that represents a link between the two types of inputs mentioned above and influences both the macroeconomics and the investments. Based on time-varying volatility, we examine implied volatility of daily returns of EUR/RON exchange rate using the standard GARCH model and the asymmetric EGARCH model, whose parameters are estimated through the maximum likelihood method and the error terms follow two distributions (Normal and Student’s t. The empirical results show EGARCH(2,1 with Asymmetric order 2 and Student’s t error terms distribution performs better than all the estimated standard GARCH models (GARCH(1,1, GARCH(1,2, GARCH(2,1 and GARCH(2,2. This conclusion is supported by the major advantage of the EGARCH model compared to the GARCH model which consists in allowing good and bad news having different impact on the

  20. Mass transfer characteristics, rheological behavior and fractal dimension of anammox granules: The roles of upflow velocity and temperature.

    Science.gov (United States)

    Shi, Zhi-Jian; Guo, Qiong; Xu, Yi-Qun; Wu, Dan; Liao, Si-Mo; Zhang, Fu-Yue; Zhang, Zheng-Zhe; Jin, Ren-Cun

    2017-11-01

    In this study, the mass transfer, rheological behavior and fractal dimension of anaerobic ammonium oxidation (anammox) granules in upflow anaerobic sludge blanket reactors at various temperatures (8.5-34.5°C) and upflow velocities (0.06, 0.18mh -1 ) were investigated. The results demonstrated that a lower temperature increased the external mass transfer coefficient and apparent viscosity and impaired the performance of anammox granules. The external mass transfer coefficient was decreased, but efficient nitrogen removal of up to 96% was achieved under high upflow velocity, which also decreased the apparent viscosity. Furthermore, a fractal dimension of up to 2.93 achieved at low temperature was higher than the previously reported values for mesophilic anammox granules. A higher upflow velocity was associated with the lower fractal dimension. Because of the disturbance in granule flaking, the effectiveness factor was less suitable than the external mass transfer coefficient for characterization of mass transfer resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Fermentation process using specific oxygen uptake rates as a process control

    Science.gov (United States)

    Van Hoek; Pim , Aristidou; Aristos , Rush; Brian

    2007-06-19

    Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

  2. Fermentation process using specific oxygen uptake rates as a process control

    Science.gov (United States)

    Van Hoek, Pim [Minnetonka, MN; Aristidou, Aristos [Maple Grove, MN; Rush, Brian [Minneapolis, MN

    2011-05-10

    Specific oxygen uptake (OUR) is used as a process control parameter in fermentation processes. OUR is determined during at least the production phase of a fermentation process, and process parameters are adjusted to maintain the OUR within desired ranges. The invention is particularly applicable when the fermentation is conducted using a microorganism having a natural PDC pathway that has been disrupted so that it no longer functions. Microorganisms of this sort often produce poorly under strictly anaerobic conditions. Microaeration controlled by monitoring OUR allows the performance of the microorganism to be optimized.

  3. Biomass is the main driver of changes in ecosystem process rates during tropical forest succession

    NARCIS (Netherlands)

    Lohbeck, M.W.M.; Poorter, L.; Martinez-Ramos, M.; Bongers, F.

    2015-01-01

    Over half of the world's forests are disturbed, and the rate at which ecosystem processes recover after disturbance is important for the services these forests can provide. We analyze the drivers' underlying changes in rates of key ecosystem processes (biomass productivity, litter productivity,

  4. A Flexible System for Processing Clinical Performance Ratings: Illustrative Applications in a Residency and Four Clerkships.

    Science.gov (United States)

    Cason, Gerald J.; And Others

    The Performance Rating portion of the University of Arkansas for Medical Sciences (UAMS) Objective Test Scoring and Performance Rating (OTS-PR) system is designed to help the clinical teacher evaluate students' clinical performance. The system collects, processes, and reports ratings of learners' performances in clinical settings. The system's 160…

  5. AUTOMATED SYSTEM OF DATA PROCESSING WITH THE IMPLEMENTATION OF RATING TECHNOLOGY OF TEACHING

    Directory of Open Access Journals (Sweden)

    О. И. Дзювина

    2014-01-01

    Full Text Available Rating technology of teaching enables independent and individual work of students, increase their motivation.Purpose: to increase the efficiency of data processing with the implementation of rating technology of teaching.Method: analysis, synthesis,experiment.Results. Developed an automated data processing system for the implementation of rating technology of teaching.Practical implication. Education.Purchase on Elibrary.ru > Buy now

  6. Rating

    OpenAIRE

    Karas, Vladimír

    2006-01-01

    Charakteristika ratingu. Dělení a druhy ratingu (rating emise × rating emitenta; dlouhodobý rating × krátkodobý rating; mezinárodní rating × lokální rating). Obecné požadavky kladené na rating. Proces tvorby ratingu. Vyžádaný rating. Nevyžádaný rating. Ratingový proces na bázi volně přístupných informací. Uplatňované ratingové systémy. Ratingová kriteria. Využití a interpretace ratingové známky. Funkce ratingu. Rating v souvislosti s BASEL II. Rating v souvislosti s hospodářskými krizemi....

  7. Evaluation of high-rate pulse processing in K-edge densitometry

    International Nuclear Information System (INIS)

    Eberle, H.; Matussek, P.; Michel-Piper, I.; Ottmar, H.

    1987-08-01

    Different pulse processing systems have been tested at high counting rates for K-edge densitometry measurements with a continuous X-ray beam. The total input counting rates presented to the gamma detector have been varied between 10 kcps and 100 kcps. This paper describes the results of the measurements, in particular the influence of high counting rates on the spectral resolution, on the pile-up behaviour, on the throughput rate, and on the K-edge densitometry results. (orig.) [de

  8. N2 production rates limited by nitrite availability in the Bay of Bengal oxygen minimum zone

    DEFF Research Database (Denmark)

    Bristow, Laura A.; Callbeck, C. M.; Larsen, M

    2017-01-01

    with isotopically labelled nitrogen compounds and analyse geochemical signatures of these processes in the water column. We find that the Bay of Bengal supports denitrifier and anammox microbial populations, mediating low, but significant N loss. Yet, unlike other oxygen minimum zones, our measurements using...

  9. The un-making of a method: From rating scales to the study of psychological processes

    DEFF Research Database (Denmark)

    Rosenbaum, Philip J.; Valsiner, Jaan

    2011-01-01

    Rating scales are standard instruments in psychology. They force the research participant to provide a numerical estimate of an assumed “degree” of some characteristic along a linear scale. We prove that such numerical estimates are artifacts based on unknown psychological processes that are used...... estimates by the rating task overlooks the qualitative (structural) relation between the implied opposites. We propose the reconstruction of the rating tasks into a method that accesses the process of meaning construction by the rater. When the rater faces a rating task, a field of meanings is constructed...

  10. THE ANALYSIS OF HEART RATE VARIABILITY IN ELITE ATHLETES DURING NON STATION NARY PROCESSES

    Directory of Open Access Journals (Sweden)

    G. V. Korobeynikov

    2016-06-01

    Full Text Available The heart rate variability during non stationary processes in athletes was studied. The 29 elite athletes were examined. The parameters of scattergram for analysis of non stationnary processes of heart rate regulation were used. The results are shows about of tendency for decrease of periodic and non periodic variations of cardiac intervals depending from characters of reaction of heart rate. The obtained result showed the aging increasing of tension of autonomic regulation of heart rate of athletes as fatigue or non adequate performance.

  11. To audit or not to audit : How is auditing being used in banks' credit rating processes?

    OpenAIRE

    Ademi, Aida; Stigborn, Ammeli

    2010-01-01

    Credit rating systems are complex processes and involve mainly two parties; a company and a bank. The complexity of a relationship between a company and a bank lies in the fact that a company usually has access to more information about the company than the bank. Hence, an auditor acts as a third party who validates the information involved in credit rating processes. The purpose of this dissertation is to explore how auditing is being used in credit rating processes and to identify the role ...

  12. Securing a robust electrical discharge drilling process by means of flow rate control

    Science.gov (United States)

    Risto, Matthias; Munz, Markus; Haas, Ruediger; Abdolahi, Ali

    2017-10-01

    This paper deals with the increase of the process robustness while drilling cemented carbide using electrical discharge machining (EDM). A demand for high efficiency in the resulting diameter is equivalent with a high robustness of the EDM drilling process. Analysis were done to investigate the process robustness (standard deviation of the borehole diameter) when drilling cemented carbide. The investigation has shown that the dielectric flow rate changes over the drilling process. In this case the flow rate decreased with a shorter tool electrode due to an uneven wear of the tool electrode's cross section. Using a controlled flow rate during the drilling process has led to a reduced standard deviation of the borehole diameter, thus to a higher process robustness when drilling cemented carbide.

  13. Separation of rate processes for isotopic exchange between hydrogen and liquid water in packed columns 10

    International Nuclear Information System (INIS)

    Butler, J.P.; Hartog, J. den; Goodale, J.W.; Rolston, J.H.

    1977-01-01

    Wetproofed platinum catalysts in packed columns promote isotopic exchange between counter-current streams of hydrogen saturated with water vapour and liquid water. The net rate of deuterium transfer from isotopically enriched hydrogen has been measured and separated into two rate processes involving the transfer of deuterium from hydrogen to water vapour and from water vapour to liquid. These are compared with independent measurements of the two rate processes to test the two-step successive exchange model for trickle bed reactors. The separated transfer rates are independent of bed height and characterize the deuterium concentrations of each stream along the length of the bed. The dependences of the transfer rates upon hydrogen and liquid flow, hydrogen pressure, platinum loading and the effect of dilution of the hydrophobic catalyst with inert hydrophilic packing are reported. The results indicate a third process may be important in the transfer of deuterium between hydrogen and liquid water. (author)

  14. Rates of convergence and asymptotic normality of curve estimators for ergodic diffusion processes

    NARCIS (Netherlands)

    J.H. van Zanten (Harry)

    2000-01-01

    textabstractFor ergodic diffusion processes, we study kernel-type estimators for the invariant density, its derivatives and the drift function. We determine rates of convergence and find the joint asymptotic distribution of the estimators at different points.

  15. Rate of Acquiring and Processing L2 Color Words in Relation to L1 Phonological Awareness

    Science.gov (United States)

    Hu, Chieh-Fang

    2008-01-01

    This study examined the effect of first language (L1) phonological awareness on the rate of learning new second language (L2) color terms and the rate of processing old color terms. Two groups of 37 children participated; they differed on L1 phonological awareness measured at Grade 3. At Grade 5, over multiple trials, the children learned new L2…

  16. The additive nonparametric and semiparametric Aalen model as the rate function for a counting process

    DEFF Research Database (Denmark)

    Scheike, Thomas Harder

    2002-01-01

    for the rate function, i.e., the instantaneous probability of an event conditional on only a selected set of covariates. When the rate function for the counting process is of Aalen form we show that the usual Aalen estimator can be used and gives almost unbiased estimates. The usual martingale based variance...

  17. Temporal analysis model extraction for optimizing modal multi-rate stream processing applications

    NARCIS (Netherlands)

    Geuns, S.J.; Hausmans, J.P.H.M.; Bekooij, Marco Jan Gerrit

    2014-01-01

    Modern real-time stream processing applications, such as Software Defined Radio (SDR) applications, typically have multiple modes and multi-rate behavior. Modes are often described using while-loops whereas multi-rate behavior is frequently described using arrays with pseudo-random indexing

  18. Shotgun metagenomic data reveals signifcant abundance but low diversity of Candidatus Scalindua marine anammox bacteria in the Arabian Sea oxygen minimum zone

    Directory of Open Access Journals (Sweden)

    laura eVillanueva

    2014-02-01

    Full Text Available Anaerobic ammonium oxidizing (anammox bacteria are responsible for a significant portion of the loss of fixed nitrogen from the oceans, making them important players in the global nitrogen cycle. To date, marine anammox bacteria found in both water columns and sediments worldwide belong almost exclusively to Candidatus Scalindua species. Recently the genome assembly of a marine anammox enrichment culture dominated by Candidatus Scalindua profunda became available and can now be used as a template to study metagenome data obtained from various oxygen minimum zones. Here, we sequenced genomic DNA from suspended particulate matter recovered at the upper (170 m deep and center (600 m area of the oxygen minimum zone in the Arabian Sea by SOLiD and Ion Torrent technology. The genome of Candidatus Scalindua profunda served as a template to collect reads. Based on the mapped reads marine anammox Abundance was estimated to be at least 0.4% in the upper and 1.7% in the center area. Single nucleotide variation (SNV analysis was performed to assess diversity of the Candidatus Scalindua populations. Most highly covered were the two diagnostic anammox genes hydrazine synthase (scal_01318c, hzsA and hydrazine dehydrogenase (scal_03295, hdh, while other genes involved in anammox metabolism (narGH, nirS, amtB, focA and ACS had a lower coverage but could still be assembled and analyzed. The results show that Candidatus Scalindua is abundantly present in the Arabian Sea OMZ, but that the diversity within the ecosystem is relatively low.

  19. Dominance of Candidatus Scalindua species in anammox community revealed in soils with different duration of rice paddy cultivation in Northeast China

    OpenAIRE

    Wang, Jing; Gu, Ji-Dong

    2012-01-01

    The anaerobic ammonium-oxidizing (anammox) bacteria play an important role in the oxygen-limited zone for nitrogen cycling, but their roles in agricultural ecosystems are still poorly understood. In this study, soil samples were taken from the rhizosphere and non-rhizosphere and from surface (0?5?cm) and subsurface (20?25?cm) layers with 1, 4, and 9?years of rice cultivation history on the typical albic soil of Northeast China to examine the diversity and distribution of anammox bacteria base...

  20. A review of control strategies for manipulating the feed rate in fed-batch fermentation processes

    DEFF Research Database (Denmark)

    Mears, Lisa; Stocks, Stuart M.; Sin, Gürkan

    2017-01-01

    A majority of industrial fermentation processes are operated in fed-batch mode. In this case, the rate of feed addition to the system is a focus for optimising the process operation, as it directly impacts metabolic activity, as well as directly affecting the volume dynamics in the system...

  1. Comparison of the Design of CO2-Capture Processes Using Equilibrium and Rate Based Models

    NARCIS (Netherlands)

    Arendsen, A. R J; Versteeg, G. F.; Van Der Lee, J.; Cota, R.; Satyro, M. A.

    2014-01-01

    The design of absorption processes with complex aqueous chemical reactions such as CO2-capture, selective H2S-removal as well as rate-limited physical separations like LNG pre-treatment is not simple or straightforward. Reaction kinetics, mass transfer, and thermodynamic-driven processes are coupled

  2. Interactions between rate processes with different timescales explain counterintuitive foraging patterns of arctic wintering eiders

    NARCIS (Netherlands)

    Heath, J.P.; Gilchrist, H.G.; Ydenberg, R.C.

    2010-01-01

    To maximize fitness, animals must respond to a variety of processes that operate at different rates or timescales. Appropriate decisions could therefore involve complex interactions among these processes. For example, eiders wintering in the arctic sea ice must consider locomotion and physiology of

  3. Rapid and accurate processing method for amide proton exchange rate measurement in proteins

    International Nuclear Information System (INIS)

    Koskela, Harri; Heikkinen, Outi; Kilpelaeinen, Ilkka; Heikkinen, Sami

    2007-01-01

    Exchange between protein backbone amide hydrogen and water gives relevant information about solvent accessibility and protein secondary structure stability. NMR spectroscopy provides a convenient tool to study these dynamic processes with saturation transfer experiments. Processing of this type of NMR spectra has traditionally required peak integration followed by exponential fitting, which can be tedious with large data sets. We propose here a computer-aided method that applies inverse Laplace transform in the exchange rate measurement. With this approach, the determination of exchange rates can be automated, and reliable results can be acquired rapidly without a need for manual processing

  4. Revisions to the SRCC Rating Process for Solar Water Heaters: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Burch, J.; Huggins, J.; Long, S.; Thornton, J.

    2012-06-01

    In the United States, annual performance ratings for solar water heaters are computed with component-based simulation models driven by typical meteorological year weather and specified water draw. Changes in the process are being implemented to enhance credibility through increased transparency and accuracy. Changes to the process include using a graphical rather than text-based model-building tool, performing analytical tests on all components and systems, checking energy balances on every component, loop, and system at every time step, comparing the results to detect outliers and potential errors, and documenting the modeling process in detail. Examples of changes in ratings are shown, along with analytical and comparative testing results.

  5. Numerical methods for realizing nonstationary Poisson processes with piecewise-constant instantaneous-rate functions

    DEFF Research Database (Denmark)

    Harrod, Steven; Kelton, W. David

    2006-01-01

    with piecewise-constant instantaneous rate functions, a capability that has been implemented in commercial simulation software. They test these algorithms in C programs and make comparisons of accuracy, speed, and variability across disparate rate functions and microprocessor architectures. Choice of optimal......Nonstationary Poisson processes are appropriate in many applications, including disease studies, transportation, finance, and social policy. The authors review the risks of ignoring nonstationarity in Poisson processes and demonstrate three algorithms for generation of Poisson processes...... algorithm could not be predicted without knowledge of microprocessor architecture....

  6. Volumetric erosion rate reduction of Hall thruster channel wall during ion sputtering process

    International Nuclear Information System (INIS)

    Yu Daren; Li Yuquan

    2007-01-01

    The mechanisms of the volumetric erosion rate reduction of the channel wall were studied theoretically and numerically in order to explain the reasons why the volumetric erosion rate of Hall thruster channel decreases over time. The results of the theoretical analysis indicate that the variation of three sputtering conditions results from the increase in the tilt angle and the erosion depth of the channel wall erosion surface during the surface evolution process. The mass loss of the Hall thruster channel wall material is a reduction process due to which the ion flux divergent angle is smaller than the value that corresponds to the sufficient condition of the reduction process. The simulation results of the channel wall erosion process qualitatively agree well with the experimental results, and the numerical analysis of the reduction process shows that the magnitude orders of three sputtering condition variation effects on the volumetric erosion rate reduction are the same, and the reduction rate reaches its maximum value in the initial operation period when the ion radiation angle equals the optimum sputtering rate angle. This work provides theoretical fundamentals of the channel wall erosion reduction process and it can be used for the lifetime prediction and optimum design of the Hall thruster

  7. Dual Rate Adaptive Control for an Industrial Heat Supply Process Using Signal Compensation Approach

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Tianyou; Jia, Yao; Wang, Hong; Su, Chun-Yi

    2017-07-09

    The industrial heat supply process (HSP) is a highly nonlinear cascaded process which uses a steam valve opening as its control input, the steam flow-rate as its inner loop output and the supply water temperature as its outer loop output. The relationship between the heat exchange rate and the model parameters, such as steam density, entropy, and fouling correction factor and heat exchange efficiency are unknown and nonlinear. Moreover, these model parameters vary in line with steam pressure, ambient temperature and the residuals caused by the quality variations of the circulation water. When the steam pressure and the ambient temperature are of high values and are subjected to frequent external random disturbances, the supply water temperature and the steam flow-rate would interact with each other and fluctuate a lot. This is also true when the process exhibits unknown characteristic variations of the process dynamics caused by the unexpected changes of the heat exchange residuals. As a result, it is difficult to control the supply water temperature and the rates of changes of steam flow-rate well inside their targeted ranges. In this paper, a novel compensation signal based dual rate adaptive controller is developed by representing the unknown variations of dynamics as unmodeled dynamics. In the proposed controller design, such a compensation signal is constructed and added onto the control signal obtained from the linear deterministic model based feedback control design. Such a compensation signal aims at eliminating the unmodeled dynamics and the rate of changes of the currently sample unmodeled dynamics. A successful industrial application is carried out, where it has been shown that both the supply water temperature and the rate of the changes of the steam flow-rate can be controlled well inside their targeted ranges when the process is subjected to unknown variations of its dynamics.

  8. Wafer size effect on material removal rate in copper CMP process

    Energy Technology Data Exchange (ETDEWEB)

    Yuh, Minjong; Jang, Soocheon; Park, Inho; Jeong, Haedo [Pusan National University, Busan (Korea, Republic of)

    2017-06-15

    The semiconductor industry has employed the Chemical mechanical planarization (CMP) to enable surface topography control. Copper has been used to build interconnects because of its low-resistivity and high-electromigration. In this study, the effect of wafer size on the Material removal rate (MRR) in copper CMP process was investigated. CMP experiments were conducted using copper blanket wafers with diameter of 100, 150, 200 and 300 mm, while temperature and friction force were measured by infrared and piezoelectric sen-sors. The MRR increases with an increase in wafer size under the same process conditions. The wafer size increased the sliding distance of pad, resulting in an increase in the process temperature. This increased the process temperature, accelerating the chemical etching rate and the dynamic etch rate. The sliding distance of the pad was proportional to the square of the wafer radius; it may be used to predict CMP results and design a CMP machine.

  9. High energy high rate pulsed power processing of materials by powder consolidation and by railgun deposition

    Science.gov (United States)

    Persad, C.; Marcus, H. L.; Weldon, W. F.

    1987-03-01

    This exploratory research program was initiated to investigate the potential of using pulse power sources for powder consolidation, deposition and other High Energy High Rate Processing. The characteristics of the High Energy High Rate (1MJ/s) powder consolidation using megampere current pulses from a Homopolar Generator, have been defined. Molybdenum Alloy TZM, A Nickel based metallic glass, Copper graphite composites, and P/M Aluminum Alloy X7091 have been investigated. The powder consolidation process produced high densification rates. Density values of 80% to 99% could be obtained with sub second high temperature exposure. Specific energy input and applied pressure were controlling process parameters. Time Temperature Transformation (TTT) concepts underpin a fundamental understanding of pulsed power processing. Deposition experiments were conducted using an exploding foil device (EFD) providing an armature feed to railgun mounted in a vacuum chamber. The material to be deposited - in plasma, gas, liquid or solid state - was accelerated electromagnetically in the railgun and deposited on a substrate.

  10. Effects of Injection Rate Profile on Combustion Process and Emissions in a Diesel Engine

    Directory of Open Access Journals (Sweden)

    Fuqiang Bai

    2017-01-01

    Full Text Available When multi-injection is implemented in diesel engine via high pressure common rail injection system, changed interval between injection pulses can induce variation of injection rate profile for sequential injection pulse, though other control parameters are the same. Variations of injection rate shape which influence the air-fuel mixing and combustion process will be important for designing injection strategy. In this research, CFD numerical simulations using KIVA-3V were conducted for examining the effects of injection rate shape on diesel combustion and emissions. After the model was validated by experimental results, five different shapes (including rectangle, slope, triangle, trapezoid, and wedge of injection rate profiles were investigated. Modeling results demonstrate that injection rate shape can have obvious influence on heat release process and heat release traces which cause different combustion process and emissions. It is observed that the baseline, rectangle (flat, shape of injection rate can have better balance between NOx and soot emissions than the other investigated shapes. As wedge shape brings about the lowest NOx emissions due to retarded heat release, it produces the highest soot emissions among the five shapes. Trapezoid shape has the lowest soot emissions, while its NOx is not the highest one. The highest NOx emissions were produced by triangle shape due to higher peak injection rate.

  11. Biomass is the main driver of changes in ecosystem process rates during tropical forest succession.

    Science.gov (United States)

    Lohbeck, Madelon; Poorter, Lourens; Martínez-Ramos, Miguel; Bongers, Frans

    2015-05-01

    Over half of the world's forests are disturbed, and the rate at which ecosystem processes recover after disturbance is important for the services these forests can provide. We analyze the drivers' underlying changes in rates of key ecosystem processes (biomass productivity, litter productivity, actual litter decomposition, and potential litter decomposition) during secondary succession after shifting cultivation in wet tropical forest of Mexico. We test the importance of three alternative drivers of ecosystem processes: vegetation biomass (vegetation quantity hypothesis), community-weighted trait mean (mass ratio hypothesis), and functional diversity (niche complementarity hypothesis) using structural equation modeling. This allows us to infer the relative importance of different mechanisms underlying ecosystem process recovery. Ecosystem process rates changed during succession, and the strongest driver was aboveground biomass for each of the processes. Productivity of aboveground stem biomass and leaf litter as well as actual litter decomposition increased with initial standing vegetation biomass, whereas potential litter decomposition decreased with standing biomass. Additionally, biomass productivity was positively affected by community-weighted mean of specific leaf area, and potential decomposition was positively affected by functional divergence, and negatively by community-weighted mean of leaf dry matter content. Our empirical results show that functional diversity and community-weighted means are of secondary importance for explaining changes in ecosystem process rates during tropical forest succession. Instead, simply, the amount of vegetation in a site is the major driver of changes, perhaps because there is a steep biomass buildup during succession that overrides more subtle effects of community functional properties on ecosystem processes. We recommend future studies in the field of biodiversity and ecosystem functioning to separate the effects of

  12. Adaptive Convergence Rates of a Dirichlet Process Mixture of Multivariate Normals

    OpenAIRE

    Tokdar, Surya T.

    2011-01-01

    It is shown that a simple Dirichlet process mixture of multivariate normals offers Bayesian density estimation with adaptive posterior convergence rates. Toward this, a novel sieve for non-parametric mixture densities is explored, and its rate adaptability to various smoothness classes of densities in arbitrary dimension is demonstrated. This sieve construction is expected to offer a substantial technical advancement in studying Bayesian non-parametric mixture models based on stick-breaking p...

  13. Point process analyses of variations in smoking rate by setting, mood, gender, and dependence

    Science.gov (United States)

    Shiffman, Saul; Rathbun, Stephen L.

    2010-01-01

    The immediate emotional and situational antecedents of ad libitum smoking are still not well understood. We re-analyzed data from Ecological Momentary Assessment using novel point-process analyses, to assess how craving, mood, and social setting influence smoking rate, as well as assessing the moderating effects of gender and nicotine dependence. 304 smokers recorded craving, mood, and social setting using electronic diaries when smoking and at random nonsmoking times over 16 days of smoking. Point-process analysis, which makes use of the known random sampling scheme for momentary variables, examined main effects of setting and interactions with gender and dependence. Increased craving was associated with higher rates of smoking, particularly among women. Negative affect was not associated with smoking rate, even in interaction with arousal, but restlessness was associated with substantially higher smoking rates. Women's smoking tended to be less affected by negative affect. Nicotine dependence had little moderating effect on situational influences. Smoking rates were higher when smokers were alone or with others smoking, and smoking restrictions reduced smoking rates. However, the presence of others smoking undermined the effects of restrictions. The more sensitive point-process analyses confirmed earlier findings, including the surprising conclusion that negative affect by itself was not related to smoking rates. Contrary to hypothesis, men's and not women's smoking was influenced by negative affect. Both smoking restrictions and the presence of others who are not smoking suppress smoking, but others’ smoking undermines the effects of restrictions. Point-process analyses of EMA data can bring out even small influences on smoking rate. PMID:21480683

  14. Scaling of black silicon processing time by high repetition rate femtosecond lasers

    Directory of Open Access Journals (Sweden)

    Nava Giorgio

    2013-11-01

    Full Text Available Surface texturing of silicon substrates is performed by femtosecond laser irradiation at high repetition rates. Various fabrication parameters are optimized in order to achieve very high absorptance in the visible region from the micro-structured silicon wafer as compared to the unstructured one. A 70-fold reduction of the processing time is demonstrated by increasing the laser repetition rate from 1 kHz to 200 kHz. Further scaling up to 1 MHz can be foreseen.

  15. Denitrification pathways and rates in the sandy sediments of the Georgia continental shelf, USA

    Directory of Open Access Journals (Sweden)

    Ingall Ellery

    2005-02-01

    Full Text Available Denitrification in continental shelf sediments has been estimated to be a significant sink of oceanic fixed nitrogen (N. The significance and mechanisms of denitrification in organic-poor sands, which comprise 70% of continental shelf sediments, are not well known. Core incubations and isotope tracer techniques were employed to determine processes and rates of denitrification in the coarse-grained, sandy sediments of the Georgia continental shelf. In these sediments, heterotrophic denitrification was the dominant process for fixed N removal. Processes such as coupled nitrification-denitrification, anammox (anaerobic ammonium oxidation, and oxygen-limited autotrophic nitrification-denitrification were not evident over the 24 and 48 h time scale of the incubation experiments. Heterotrophic denitrification processes produce 22.8–34.1 μmole N m-2 d-1 of N2 in these coarse-grained sediments. These denitrification rates are approximately two orders of magnitude lower than rates determined in fine-grained shelf sediments. These lower rates may help reconcile unbalanced marine N budgets which calculate global N losses exceeding N inputs.

  16. General Purpose Graphics Processing Unit Based High-Rate Rice Decompression and Reed-Solomon Decoding

    Energy Technology Data Exchange (ETDEWEB)

    Loughry, Thomas A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    As the volume of data acquired by space-based sensors increases, mission data compression/decompression and forward error correction code processing performance must likewise scale. This competency development effort was explored using the General Purpose Graphics Processing Unit (GPGPU) to accomplish high-rate Rice Decompression and high-rate Reed-Solomon (RS) decoding at the satellite mission ground station. Each algorithm was implemented and benchmarked on a single GPGPU. Distributed processing across one to four GPGPUs was also investigated. The results show that the GPGPU has considerable potential for performing satellite communication Data Signal Processing, with three times or better performance improvements and up to ten times reduction in cost over custom hardware, at least in the case of Rice Decompression and Reed-Solomon Decoding.

  17. Variations of the Earth's rotation rate and cyclic processes in geodynamics

    Directory of Open Access Journals (Sweden)

    B.W. Levin

    2017-05-01

    Full Text Available The authors analyzed the relationship between variations of the Earth's rotation rate and the geodynamic processes within the Earth's body, including seismic activity. The rotation rate of a planet determines its uniaxial compression along the axis of rotation and the areas of various surface elements of the body. The Earth's ellipticity variations, caused naturally by the rotation rate variations, are manifested in vertical components of precise GPS measurements. Comparative analysis of these variations is considered in view of modern theoretical ideas concerning the Earth's figure. The results justify further research that is of interest for improvement of space systems and technologies.

  18. Rate estimation in partially observed Markov jump processes with measurement errors

    OpenAIRE

    Amrein, Michael; Kuensch, Hans R.

    2010-01-01

    We present a simulation methodology for Bayesian estimation of rate parameters in Markov jump processes arising for example in stochastic kinetic models. To handle the problem of missing components and measurement errors in observed data, we embed the Markov jump process into the framework of a general state space model. We do not use diffusion approximations. Markov chain Monte Carlo and particle filter type algorithms are introduced, which allow sampling from the posterior distribution of t...

  19. Intact polar lipids of Thaumarchaeota and anammox bacteria as indicators of N cycling in the eastern tropical North Pacific oxygen-deficient zone

    NARCIS (Netherlands)

    Sollai, M.; Hopmans, E.C.; Schouten, S.; Keil, R.G.; Sinninghe Damsté, J.S.

    2015-01-01

    In the last decade our understanding of the marine nitrogen cycle has improved considerably thanks to the discovery of two novel groups of microorganisms: ammonia-oxidizing archaea (AOA) and anaerobic ammonia-oxidizing (anammox) bacteria. Both groups are important in oxygen-deficient zones (ODZs),

  20. Intact polar lipids of Thaumarchaeota and anammox bacteria as indicators of N cycling in the eastern tropical North Pacific oxygen-deficient zone

    NARCIS (Netherlands)

    Sollai, M.; Hopmans, Ellen C.; Schouten, Stefan; Keil, R.G.; Sinninghe Damste, J.S.

    2015-01-01

    . In the last decade our understanding of the marine nitrogen cycle has improved considerably thanks to the discovery of two novel groups of microorganisms: ammonia-oxidizing archaea (AOA) and anaerobic ammonia-oxidizing (anammox) bacteria. Both groups are important in oxygen-deficient zones (ODZs),

  1. On the time-homogeneous Ornstein–Uhlenbeck process in the foreign exchange rates

    International Nuclear Information System (INIS)

    Fonseca, Regina C.B. da; Matsushita, Raul Y.; Castro, Márcio T. de; Figueiredo, Annibal

    2015-01-01

    Since Gaussianity and stationarity assumptions cannot be fulfilled by financial data, the time-homogeneous Ornstein–Uhlenbeck (THOU) process was introduced as a candidate model to describe time series of financial returns [1]. It is an Ornstein–Uhlenbeck (OU) process in which these assumptions are replaced by linearity and time-homogeneity. We employ the OU and THOU processes to analyze daily foreign exchange rates against the US dollar. We confirm that the OU process does not fit the data, while in most cases the first four cumulants patterns from data can be described by the THOU process. However, there are some exceptions in which the data do not follow linearity or time-homogeneity assumptions. - Highlights: • Gaussianity and stationarity assumptions replaced by linearity and time-homogeneity. • We revisit the time-homogeneous Ornstein–Uhlenbeck (THOU) process. • We employ the THOU process to analyze foreign exchange rates against the US dollar. • The first four cumulants patterns from data can be described by the THOU process

  2. Analysis of heating effect on the process of high deposition rate microcrystalline silicon

    International Nuclear Information System (INIS)

    Xiao-Dan, Zhang; He, Zhang; Chang-Chun, Wei; Jian, Sun; Guo-Fu, Hou; Shao-Zhen, Xiong; Xin-Hua, Geng; Ying, Zhao

    2010-01-01

    A possible heating effect on the process of high deposition rate microcrystalline silicon has been studied. It includes the discharge time-accumulating heating effect, discharge power, inter-electrode distance, and total gas flow rate induced heating effect. It is found that the heating effects mentioned above are in some ways quite similar to and in other ways very different from each other. However, all of them will directly or indirectly cause the increase of the substrate surface temperature during the process of depositing microcrystalline silicon thin films, which will affect the properties of the materials with increasing time. This phenomenon is very serious for the high deposition rate of microcrystalline silicon thin films because of the high input power and the relatively small inter-electrode distance needed. Through analysis of the heating effects occurring in the process of depositing microcrystalline silicon, it is proposed that the discharge power and the heating temperature should be as low as possible, and the total gas flow rate and the inter-electrode distance should be suitable so that device-grade high quality deposition rate microcrystalline silicon thin films can be fabricated

  3. Modeling banded vegetation patterns in semiarid regions: Interdependence between biomass growth rate and relevant hydrological processes

    Science.gov (United States)

    Ursino, N.

    2007-04-01

    Vegetation patterns, such as regular spots and bands, have been observed in arid and semiarid lands. One of the most common explanations for vegetation banding is that the homogeneous steady state solution of soil moisture and vegetation biomass density balance, expressed in the form of a bucket model, may be unstable under conditions of scarce mean annual rainfall. Even though the theory seems to support our intuitive explanation of the phenomenon, there are still unresolved questions concerning soil parameterization, relevant hydrological processes, and the way plant physiology should be modeled in arid and semiarid environments where vegetation patterns have been observed. This paper examines the interrelation between hydrological processes and plant physiology. The biomass growth rate resembles plant physiology within the bucket model and determines the survival plant strategy given a limited soil moisture availability. The fact that very different hypotheses concerning the biomass growth rate have been formulated has not yet been given the important consideration it deserves. Different models for vegetation banding will be considered here. They are formulated by introducing different growth rates within the same soil moisture and vegetation balance equations. Linear stability analysis and numerical integration of the different models showed some relevant interrelation between hydrological and physiological features. It was demonstrated that the relation between biomass growth rate and biomass density determines which hydrological process enables vegetation pattern initiation. The discussion of this result leads to a critical review of previously published hypotheses on plant physiology and hydrological processes inducing vegetation organization.

  4. The effect of the composition and production process of concrete on the 222Rn exhalation rate

    NARCIS (Netherlands)

    Jong, P. de; Dijk, W. van; Hulst, J.G.A. van; Heijningen, R.J.J. van

    1997-01-01

    In a series of 18 concrete samples, the influence of several parameters related to composition and production processes on the radon exhalation rate was studied. The investigated parameters were: amount and type of cement, water-cement ratio, curing conditions and curing time, type of aggregates,

  5. Beta decay rates for nuclei with 115 process ...

    Indian Academy of Sciences (India)

    ∗E-mail: chakra@csupomona.edu. MS received 13 November 2005; revised 11 January 2006; accepted 15 March 2006. Abstract. For r-process nucleosynthesis the β-decay rates for a number of neutron-rich intermediate heavy nuclei are calculated. The model for the β-strength function is able to reproduce the observed ...

  6. High-precision (p,t) reactions to determine reaction rates of explosive stellar processes

    NARCIS (Netherlands)

    Matić, Andrija

    2007-01-01

    The aim of my study was to investigate the nuclear structure of 22Mg and 26Si. These two nuclei play a significant role in stellar reaction processes at high temperatures. On base of the obtained nuclear structure we calculated the stellar reaction rates for the following reactions: 18Ne(α,p)21Na,

  7. Hierarchical programming language for modal multi-rate real-time stream processing applications

    NARCIS (Netherlands)

    Geuns, S.J.; Hausmans, J.P.H.M.; Bekooij, Marco Jan Gerrit

    2014-01-01

    Modal multi-rate stream processing applications with real-time constraints which are executed on multi-core embedded systems often cannot be conveniently specified using current programming languages. An important issue is that sequential programming languages do not allow for convenient programming

  8. On diffusion processes with variable drift rates as models for decision making during learning

    International Nuclear Information System (INIS)

    Eckhoff, P; Holmes, P; Law, C; Connolly, P M; Gold, J I

    2008-01-01

    We investigate Ornstein-Uhlenbeck and diffusion processes with variable drift rates as models of evidence accumulation in a visual discrimination task. We derive power-law and exponential drift-rate models and characterize how parameters of these models affect the psychometric function describing performance accuracy as a function of stimulus strength and viewing time. We fit the models to psychophysical data from monkeys learning the task to identify parameters that best capture performance as it improves with training. The most informative parameter was the overall drift rate describing the signal-to-noise ratio of the sensory evidence used to form the decision, which increased steadily with training. In contrast, secondary parameters describing the time course of the drift during motion viewing did not exhibit steady trends. The results indicate that relatively simple versions of the diffusion model can fit behavior over the course of training, thereby giving a quantitative account of learning effects on the underlying decision process

  9. Coupled physical/biogeochemical modeling including O2-dependent processes in the Eastern Boundary Upwelling Systems: application in the Benguela

    Directory of Open Access Journals (Sweden)

    E. Gutknecht

    2013-06-01

    Full Text Available The Eastern Boundary Upwelling Systems (EBUS contribute to one fifth of the global catches in the ocean. Often associated with Oxygen Minimum Zones (OMZs, EBUS represent key regions for the oceanic nitrogen (N cycle. Important bioavailable N loss due to denitrification and anammox processes as well as greenhouse gas emissions (e.g, N2O occur also in these EBUS. However, their dynamics are currently crudely represented in global models. In the climate change context, improving our capability to properly represent these areas is crucial due to anticipated changes in the winds, productivity, and oxygen content. We developed a biogeochemical model (BioEBUS taking into account the main processes linked with EBUS and associated OMZs. We implemented this model in a 3-D realistic coupled physical/biogeochemical configuration in the Namibian upwelling system (northern Benguela using the high-resolution hydrodynamic ROMS model. We present here a validation using in situ and satellite data as well as diagnostic metrics and sensitivity analyses of key parameters and N2O parameterizations. The impact of parameter values on the OMZ off Namibia, on N loss, and on N2O concentrations and emissions is detailed. The model realistically reproduces the vertical distribution and seasonal cycle of observed oxygen, nitrate, and chlorophyll a concentrations, and the rates of microbial processes (e.g, NH4+ and NO2− oxidation, NO3− reduction, and anammox as well. Based on our sensitivity analyses, biogeochemical parameter values associated with organic matter decomposition, vertical sinking, and nitrification play a key role for the low-oxygen water content, N loss, and N2O concentrations in the OMZ. Moreover, the explicit parameterization of both steps of nitrification, ammonium oxidation to nitrate with nitrite as an explicit intermediate, is necessary to improve the representation of microbial activity linked with the OMZ. The simulated minimum oxygen

  10. On the time-homogeneous Ornstein-Uhlenbeck process in the foreign exchange rates

    Science.gov (United States)

    da Fonseca, Regina C. B.; Matsushita, Raul Y.; de Castro, Márcio T.; Figueiredo, Annibal

    2015-10-01

    Since Gaussianity and stationarity assumptions cannot be fulfilled by financial data, the time-homogeneous Ornstein-Uhlenbeck (THOU) process was introduced as a candidate model to describe time series of financial returns [1]. It is an Ornstein-Uhlenbeck (OU) process in which these assumptions are replaced by linearity and time-homogeneity. We employ the OU and THOU processes to analyze daily foreign exchange rates against the US dollar. We confirm that the OU process does not fit the data, while in most cases the first four cumulants patterns from data can be described by the THOU process. However, there are some exceptions in which the data do not follow linearity or time-homogeneity assumptions.

  11. Parallel photonic information processing at gigabyte per second data rates using transient states.

    Science.gov (United States)

    Brunner, Daniel; Soriano, Miguel C; Mirasso, Claudio R; Fischer, Ingo

    2013-01-01

    The increasing demands on information processing require novel computational concepts and true parallelism. Nevertheless, hardware realizations of unconventional computing approaches never exceeded a marginal existence. While the application of optics in super-computing receives reawakened interest, new concepts, partly neuro-inspired, are being considered and developed. Here we experimentally demonstrate the potential of a simple photonic architecture to process information at unprecedented data rates, implementing a learning-based approach. A semiconductor laser subject to delayed self-feedback and optical data injection is employed to solve computationally hard tasks. We demonstrate simultaneous spoken digit and speaker recognition and chaotic time-series prediction at data rates beyond 1 Gbyte/s. We identify all digits with very low classification errors and perform chaotic time-series prediction with 10% error. Our approach bridges the areas of photonic information processing, cognitive and information science.

  12. Sedimentation rates and depositional processes in Lake Superior from 210Pb geochronology

    International Nuclear Information System (INIS)

    Evans, J.E.; Johnson, T.C.; Alexander, E.C. Jr.; Lively, R.S.; Eisenreich, S.J.

    1981-01-01

    Sedimentation rates range from 0.01 to 0.32 cm/yr in 17 sediment box cores from Lake Superior, as determined by 210 Pb geochronology. Shoreline erosion and resuspension of nearshore sediments causes moderate to high (0.05-0.11 cm/yr) sedimentation rates in the western arm of Lake Superior. Sedimentation rates are very high (> 0.15 cm/yr) in marginal bays adjoining Lake Superior; and moderate to very high (0.07-0.19 cm/yr) in open lake regions adjacent to marginal bays. Resuspension of nearshore and shoal top sediments in southern and southeastern Lake Superior by storms is responsible for depositional anomalies in 210 Pb profiles corresponding to 1905, 1916-1918, and 1940 storms. Sedimentation rates are very low (0.01-0.03 cm/yr) in the central basins due to isolation from sediment sources. These data indicate that sedimentation rates and processes vary significantly in different regions of Lake Superior. The sedimentation rates provided by this study, in conjunction with previously-reported sedimentation rates, yield a better understanding of the Lake Superior depositional environment

  13. Parameter study of r-process lanthanide production and heating rates in kilonovae

    Science.gov (United States)

    Lippuner, Jonas; Roberts, Luke F.

    2015-04-01

    Explosive r-process nucleosynthesis in material ejected during compact object mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients are sensitive to the composition of the material after nuclear burning ceases, as the composition determines the local heating rate from nuclear decays and the opacity. The presence of lanthanides in the ejecta can drastically increase the opacity. We use the new general-purpose nuclear reaction network SkyNet to run a parameter study of r-process nucleosynthesis for a range of initial electron fractions Ye, initial entropies s, and density decay timescales τ. We find that the ejecta is lanthanide-free for Ye >~ 0 . 22 - 0 . 3 , depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Ye lead to reduced heating rates, because single nuclides dominate the heating. With a simple model we estimate the luminosity, time, and effective temperature at the peak of the light curve. Since the opacity is much lower in the lanthanide-free case, we find the luminosity peaks much earlier at ~ 1 day vs. ~ 15 days in the lanthanide-rich cases. Although there is significant variation in the heating rate with Ye, changes in the heating rate do not mitigate the effect of the lanthanides. This research is partially supported by NSF under Award Numbers AST-1333520 and AST-1205732.

  14. Research on the Signal Process of a Bell-Shaped Vibratory Angular Rate Gyro

    Science.gov (United States)

    Su, Zhong; Liu, Ning; Li, Qing; Fu, Mengyin; Liu, Hong; Fan, Junfang

    2014-01-01

    A bell-shaped vibratory angular rate gyro, which is inspired by the Chinese traditional bell, is a kind of axisymmetric shell resonator gyroscope. Its sensitive element is a vibratory-like Chinese traditional bell, using a piezoelectric element on the wall of the vibrator to detect the standing wave's precession to solve the input angular rate. This work mainly studies the circuit system of a bell-shaped vibratory angular rate gyro. It discusses the process of circuit system design, analysis and experiment, in detail, providing the foundation to develop a bell-shaped vibratory angular rate gyro. Since the bell-shaped resonator's curved structure has the characteristics of large noise in the piezoelectric signal and large harmonics, this paper analyzes its working and signal detection method, then gives the whole plan of the circuit system, including the drive module, the detection module and the control loop. It also studies every part of the whole system, gives a detailed design and analysis process and proves part of the circuit system using digital simulation. At the end of the article, the test result of the circuit system shows that it can remove the disadvantages of the curved structure having large noise in the piezoelectric signal and large harmonics and is more effective at solving the input angular rate. PMID:24633451

  15. Research on the Signal Process of a Bell-Shaped Vibratory Angular Rate Gyro

    Directory of Open Access Journals (Sweden)

    Zhong Su

    2014-03-01

    Full Text Available A bell-shaped vibratory angular rate gyro, which is inspired by the Chinese traditional bell, is a kind of axisymmetric shell resonator gyroscope. Its sensitive element is a vibratory-like Chinese traditional bell, using a piezoelectric element on the wall of the vibrator to detect the standing wave’s precession to solve the input angular rate. This work mainly studies the circuit system of a bell-shaped vibratory angular rate gyro. It discusses the process of circuit system design, analysis and experiment, in detail, providing the foundation to develop a bell-shaped vibratory angular rate gyro. Since the bell-shaped resonator’s curved structure has the characteristics of large noise in the piezoelectric signal and large harmonics, this paper analyzes its working and signal detection method, then gives the whole plan of the circuit system, including the drive module, the detection module and the control loop. It also studies every part of the whole system, gives a detailed design and analysis process and proves part of the circuit system using digital simulation. At the end of the article, the test result of the circuit system shows that it can remove the disadvantages of the curved structure having large noise in the piezoelectric signal and large harmonics and is more effective at solving the input angular rate.

  16. A review of control strategies for manipulating the feed rate in fed-batch fermentation processes.

    Science.gov (United States)

    Mears, Lisa; Stocks, Stuart M; Sin, Gürkan; Gernaey, Krist V

    2017-03-10

    A majority of industrial fermentation processes are operated in fed-batch mode. In this case, the rate of feed addition to the system is a focus for optimising the process operation, as it directly impacts metabolic activity, as well as directly affecting the volume dynamics in the system. This review covers a range of strategies which have been employed to use the feed rate as a manipulated variable in a control strategy. The feed rate is chosen as the focus for this review, as it is seen that this variable may be used towards many different objectives depending on the process of interest, the characteristics of the strain, or the product being produced, which leads to different drivers for process optimisation. This review summarises the methods, as well as focusing on the different objectives for the controllers, and the choice of measured variables involved in the strategy. The discussion includes a summary of considerations for control strategy development. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Rate of information processing and reaction time of aircraft pilots and non-pilots

    Directory of Open Access Journals (Sweden)

    Werner Barkhuizen

    2002-09-01

    Full Text Available Reaction time and rate of information processing are cited as critical components in the make-up of pilots. A need was identified to establish the validity of various chronometric measures in the selection of pilots. Fifty-eight military and commercial pilots and twenty non-pilots were subjected to Schepers’ Computerised Information Processing Test Battery, which measures reaction time, form discrimination time, colour discrimination time, rate of information processing (perceptual and rate of information processing (conceptual. Five hypotheses and one postulate were formulated and tested. The results indicate that pilots could be differentiated from non-pilots with 92,3% accuracy. However, the results need to be cross-validated before they are used for selection. Opsomming Reaksietyd en tempo van inligtingverwerking word as kritieke komponente in die samestelling van vlieëniers beskou. ‘n Behoefte is geïdentifiseer om die geldigheid van verskeie chronometriese metinge in vlieënierskeuring te bepaal. Agt en vyftig militêre en kommersiële vlieëniers en twintig nie-vlieëniers is onderwerp aan Schepers se Gerekenariseerde Inligtingverwerkingstoets-battery wat reaksietyd, vormdiskriminasietyd, kleurdiskriminasietyd, tempo van inligtingverwerking (perseptueel en tempo van inligtingverwerking (konseptueel meet. Vyf hipoteses en een postulaat is gestel en getoets. Die resultate dui daarop dat vlieëniers met 92,3% akkuraatheid van nievlieëniers onderskei kan word. Die resultate behoort egter eers gekruisvalideer te word voordat dit finaal vir keuring gebruik kan word.

  18. Rate-Independent Processes with Linear Growth Energies and Time-Dependent Boundary Conditions

    Czech Academy of Sciences Publication Activity Database

    Kružík, Martin; Zimmer, J.

    2012-01-01

    Roč. 5, č. 3 (2012), s. 591-604 ISSN 1937-1632 R&D Projects: GA AV ČR IAA100750802 Grant - others:GA ČR(CZ) GAP201/10/0357 Institutional research plan: CEZ:AV0Z10750506 Keywords : concentrations * oscillations * time-dependent boundary conditions * rate-independent evolution Subject RIV: BA - General Mathematics http://library.utia.cas.cz/separaty/2011/MTR/kruzik-rate-independent processes with linear growth energies and time-dependent boundary conditions.pdf

  19. High-rate anisotropic ablation and deposition of polytetrafluoroethylene using synchrotron radiation process

    International Nuclear Information System (INIS)

    Inayoshi, Muneto; Ikeda, Masanobu; Hori, Masaru; Goto, Toshio; Hiramatsu, Mineo; Hiraya, Atsunari.

    1995-01-01

    Both anisotropic ablation and thin film formation of polytetrafluoroethylene (PTFE) were successfully demonstrated using synchrotron radiation (SR) irradiation of PTFE, that is, the SR ablation process. Anisotropic ablation by the SR irradiation was performed at an extremely high rate of 3500 μm/min at a PTFE target temperature of 200degC. Moreover, a PTFE thin film was formed at a high rate of 2.6 μm/min using SR ablation of PTFE. The chemical structure of the deposited film was similar to that of the PTFE target as determined from Fourier transform infrared absorption spectroscopy (FT-IR) analysis. (author)

  20. Pacific Northwest geomorphology and hydrology: rates and probabilities of selected processes and events

    International Nuclear Information System (INIS)

    Tubbs, D.W.

    1979-01-01

    This report presents results of one of the geomorphological and hydrological studies that have been conducted for the release scenario analysis of the Waste Isolation Safety Assessment Program (WISAP). Three general topics are considered: (1) determination of rates of denudation, (2) estimation of the probability of flooding due to each of several causes, and (3) evaluation of other surface processes that should be considered in the release scenario analysis. The third general topic was ultimately narrowed to the possible effects of landsliding. Rates of erosion are expressed as centimeters per 100 years, except that the original units are retained in figures taken from other sources. Probabilities are also expressed per 100 years

  1. Systematic design of membership functions for fuzzy-logic control: A case study on one-stage partial nitritation/anammox treatment systems.

    Science.gov (United States)

    Boiocchi, Riccardo; Gernaey, Krist V; Sin, Gürkan

    2016-10-01

    A methodology is developed to systematically design the membership functions of fuzzy-logic controllers for multivariable systems. The methodology consists of a systematic derivation of the critical points of the membership functions as a function of predefined control objectives. Several constrained optimization problems corresponding to different qualitative operation states of the system are defined and solved to identify, in a consistent manner, the critical points of the membership functions for the input variables. The consistently identified critical points, together with the linguistic rules, determine the long term reachability of the control objectives by the fuzzy logic controller. The methodology is highlighted using a single-stage side-stream partial nitritation/Anammox reactor as a case study. As a result, a new fuzzy-logic controller for high and stable total nitrogen removal efficiency is designed. Rigorous simulations are carried out to evaluate and benchmark the performance of the controller. The results demonstrate that the novel control strategy is capable of rejecting the long-term influent disturbances, and can achieve a stable and high TN removal efficiency. Additionally, the controller was tested, and showed robustness, against measurement noise levels typical for wastewater sensors. A feedforward-feedback configuration using the present controller would give even better performance. In comparison, a previously developed fuzzy-logic controller using merely expert and intuitive knowledge performed worse. This proved the importance of using a systematic methodology for the derivation of the membership functions for multivariable systems. These results are promising for future applications of the controller in real full-scale plants. Furthermore, the methodology can be used as a tool to help systematically design fuzzy logic control applications for other biological processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Investigations of effect of phase change mass transfer rate on cavitation process with homogeneous relaxation model

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhixia; Zhang, Liang; Saha, Kaushik; Som, Sibendu; Duan, Lian; Wang, Qian

    2017-12-01

    The super high fuel injection pressure and micro size of nozzle orifice has been an important development trend for the fuel injection system. Accordingly, cavitation transient process, fuel compressibility, amount of noncondensable gas in the fuel and cavitation erosion have attracted more attention. Based on the fact of cavitation in itself is a kind of thermodynamic phase change process, this paper takes the perspective of the cavitation phase change mass transfer process to analyze above mentioned phenomenon. The two-phase cavitating turbulent flow simulations with VOF approach coupled with HRM cavitation model and U-RANS of standard k-ε turbulence model were performed for investigations of cavitation phase change mass transfer process. It is concluded the mass transfer time scale coefficient in the Homogenous Relaxation Model (HRM) representing mass transfer rate should tend to be as small as possible in a condition that ensured the solver stable. At very fast mass transfer rate, the phase change occurs at very thin interface between liquid and vapor phase and condensation occurs more focused and then will contribute predictably to a more serious cavitation erosion. Both the initial non-condensable gas in fuel and the fuel compressibility can accelerate the cavitation mass transfer process.

  3. Low-energy rate enhancement in recombination processes of electrons into bare uranium ions

    International Nuclear Information System (INIS)

    Wu Yong; Zeng Siliang; Duan Bin; Yan Jun; Wang Jianguo; Chinese Academy of Sciences, Lanzhou; Dong Chenzhong; Ma Xinwen

    2007-01-01

    Based on the Dirac-Fork-Slater method combined with the multichannel quantum defect theory, the recombination processes of electrons into bare uranium ions (U 92+ ) are investigated in the relative energy range close to zero, and the x-ray spectrum emitted in the direct radiative recombination and cascades processes are simulated. Compared with the recent measurement, it is found that the rate enhancement comes from the additional populations on high Rydberg states. These additional populations may be produced by other recombination mechanisms, such as the external electric-magnetic effects and the many-body correlation effects, which still remains an open problem. (authors)

  4. Transient kinetics and rate limiting steps for the processive cellobiohydrolase Cel7A

    DEFF Research Database (Denmark)

    Cruys-Bagger, Nicolaj; Hirosuke, Tatsumi; Robin Ren, Guilin

    2013-01-01

    Cellobiohydrolases are exo-acting, processive enzymes, which effectively hydrolyze crystalline cellulose. They have attracted considerable interest due to their role in both in natural carbon cycling and industrial enzyme cocktails used for the deconstruction of cellulosic biomass, but many...... mechanistic and regulatory aspects of their heterogeneous catalysis remain poorly understood. Here we address this by applying a deterministic model to real-time kinetic data with high temporal resolution. We used two variants of the cellobiohydrolase Cel7A from H. jecorina, and three types of cellulose...... as substrate. Analysis of the pre-steady state regime allowed delineation rate constants for both fast and slow steps in the enzymatic cycle and assessment of how these constants influenced the rate of hydrolysis at quasi-steady state. Processive movement on the cellulose strand advanced with characteristic...

  5. Recursive Estimation for Dynamical Systems with Different Delay Rates Sensor Network and Autocorrelated Process Noises

    Directory of Open Access Journals (Sweden)

    Jianxin Feng

    2014-01-01

    Full Text Available The recursive estimation problem is studied for a class of uncertain dynamical systems with different delay rates sensor network and autocorrelated process noises. The process noises are assumed to be autocorrelated across time and the autocorrelation property is described by the covariances between different time instants. The system model under consideration is subject to multiplicative noises or stochastic uncertainties. The sensor delay phenomenon occurs in a random way and each sensor in the sensor network has an individual delay rate which is characterized by a binary switching sequence obeying a conditional probability distribution. By using the orthogonal projection theorem and an innovation analysis approach, the desired recursive robust estimators including recursive robust filter, predictor, and smoother are obtained. Simulation results are provided to demonstrate the effectiveness of the proposed approaches.

  6. Climate Does Matter: Quantifying Rates and Processes for a Southern California Climate Gradient

    Science.gov (United States)

    Dixon, J. L.; Heimsath, A. M.; Kaste, J. M.; Amundson, R.

    2005-12-01

    Climate impacts Earth surface evolution by helping to set erosional processes. Despite the critical link between climate forcing and landscape change, field-based studies quantifying the connection are rare. Here, we use four independent, field-based methodologies to examine rates and mechanisms of erosion and provide a mechanistic connection between climate forcing and landscape response. We focus on a well-studied climate gradient for the southwestern Sierra Nevada, California, using four climate zones from the low elevation oak grasslands to the high, periglacial crest of the range. Catchment-averaged, hillslope and bare rock erosion rates are quantified using in situ produced cosmogenic 10-Be. Nuclide-determined denudation rates range from about 30 to 300 m/Ma, depending on erosional process. We also analyzed the fallout-delivered short-lived nuclides, 210-Pb and 137-Cs, in soils, as well as the bulk and trace chemistry of soils and saprolite for the climatic end-members (high and low elevation field sites) to quantify dominant transport processes and chemical weathering rates. Results show three orders of magnitude differences in soil zirconium percent depletion between the extremes, quantifying higher intensities of chemical weathering at lower elevations. Chemical weathering rates range from about 3 m/Ma at the high elevation site to about 70 m/Ma at the low elevation site, accounting for 12 to 70 % of the total denudation, respectively. Additionally, activity profiles for fallout 210-Pb and 137-Cs differ markedly between sites. Deeper profiles and subsurface activity maxima at the low elevation site indicate the dominance of soil transport by mammal burrowing, while depth depletion of nuclides at the high elevation site suggests surface sediment removal by overland flow. When combined, our results from these independent methodologies quantify how climate helps drive land surface evolution.

  7. Large-scale calculations of the beta-decay rates and r-process nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Borzov, I.N.; Goriely, S. [Inst. d`Astronomie et d`Astrophysique, Univ. Libre de Bruxelles, Campus Plaine, Bruxelles (Belgium); Pearson, J.M. [Inst. d`Astronomie et d`Astrophysique, Univ. Libre de Bruxelles, Campus Plaine, Bruxelles (Belgium)]|[Lab. de Physique Nucleaire, Univ. de Montreal, Montreal (Canada)

    1998-06-01

    An approximation to a self-consistent model of the ground state and {beta}-decay properties of neutron-rich nuclei is outlined. The structure of the {beta}-strength functions in stable and short-lived nuclei is discussed. The results of large-scale calculations of the {beta}-decay rates for spherical and slightly deformed nuclides of relevance to the r-process are analysed and compared with the results of existing global calculations and recent experimental data. (orig.)

  8. Supplier Outreach and Process Control (SOPC) and Supplier Rating Initiative (SRI)

    Science.gov (United States)

    Crenshaw, Harrel

    2003-01-01

    The viewgraph presentation presents an overview of NASA's Supplier Outreach and Process Control (SOPC) and Supplier Risk Initiatives. The discussion of the SOPC examines its importance, current groups who are involved, provides a mission statement, and describes outreach activities and how suppliers are selected. The discussion of the Supplier Risk Initiative examines the variety of ways that integrity, availability, and assurance factor in to supplier risk and describes a new supplier rating program.

  9. Isotopic Monitoring of N2O Emissions from Wastewater Treatment: Evidence for N2O Production Associated with Anammox Metabolism?

    Science.gov (United States)

    Harris, E. J.; Wunderlin, P.; Joss, A.; Emmenegger, L.; Kipf, M.; Wolf, B.; Mohn, J.

    2015-12-01

    Microbial production is the major source of N2O, the strongest greenhouse gas produced within the nitrogen cycle, and the most important stratospheric ozone destructant released in the 21st century. Wastewater treatment is an important and growing source of N2O, with best estimates predicting N2O emissions from this sector will have increased by >25% by 2020. Novel treatment employing partial nitritation-anammox, rather than traditional nitrification-denitrification, has the potential to achieve a neutral carbon footprint due to increased biogas production - if N2O production accounts for treatment can be applied to our understanding of N cycling in the natural environment. This study presents the first online isotopic measurements of offgas N2O from a partial-nitritation anammox reactor 1. The measured N2O isotopic composition - in particular the N2O isotopic site preference (SP = δ15Nα - δ15Nβ) - was used to understand N2O production pathways in the reactor. When N2O emissions peaked due to high dissolved oxygen concentrations, low SP showed that N2O was produced primarily via nitrifier denitrification by ammonia oxidizing bacteria (AOBs). N2O production by AOBs via NH2OH oxidation, in contrast, did not appear to be important under any conditions. Over the majority of the one-month measurement period, the measured SP was much higher than expected following our current understanding of N2O production pathways 2. SP reached 41‰ during normal operating conditions and achieved a maximum of 45‰ when nitrite was added under anoxic conditions. These results could be explained by unexpectedly strong heterotrophic N2O reduction despite low dissolved organic matter concentrations, or by an incomplete understanding of isotopic fractionation during N2O production from NH2OH oxidation by AOBs - however the explanation most consistent with all results is a previously unknown N2O production pathway associated with anammox metabolism. Harris et al. (2015) Water Res., 83

  10. Analytical Hierarchy Process for Developing a Building Performance-Risk Rating Tool

    Directory of Open Access Journals (Sweden)

    Khalil Natasha

    2016-01-01

    Full Text Available The need to optimize the performance of buildings has increased consequently due to the expansive supply of facilities in higher education building (HEB. Proper performance assessment as a proactive measure may help university building in achieving performance optimization. However, the current maintenance programs or performance evaluation in the HEB is a systemic and cyclic process where maintenance is considered as an operational issue and not as opposed to a strategic issue. Hence, this paper proposed a Building Performance Risk Rating Tool (BPRT as an improved measure for building performance evaluation by addressing the users' risk in health and safety aspects. The BPRT is developed from the result of a rating index using the Analytical Hierarchy Process (AHP method. 12 facilities management (FM experts and practitioners were involved in the rating process. The subjective weightings are analysed using the AHP computer software, the Expert Choice 11. The establishment of the BPRT was introduced as an aid of improvement towards the current performance assessment of HEB by emerging the concept of building performance and risk into a numerical strategic approach

  11. Probing polymer crystallization at processing-relevant cooling rates with synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Cavallo, Dario, E-mail: Dario.cavallo@unige.it [University of Genoa, Dept. of Chemistry and Industrial Chemistry, Via Dodecaneso 31, 16146 Genoa (Italy); Portale, Giuseppe [ESRF, Dubble CRG, Netherlands Organization of Scientific Research (NWO), 38043 Grenoble (France); Androsch, René [Martin-Luther-University Halle-Wittenberg, Center of Engineering Sciences, D-06099 Halle/S. (Germany)

    2015-12-17

    Processing of polymeric materials to produce any kind of goods, from films to complex objects, involves application of flow fields on the polymer melt, accompanied or followed by its rapid cooling. Typically, polymers solidify at cooling rates which span over a wide range, from a few to hundreds of °C/s. A novel method to probe polymer crystallization at processing-relevant cooling rates is proposed. Using a custom-built quenching device, thin polymer films are ballistically cooled from the melt at rates between approximately 10 and 200 °C/s. Thanks to highly brilliant synchrotron radiation and to state-of-the-art X-ray detectors, the crystallization process is followed in real-time, recording about 20 wide angle X-ray diffraction patterns per second while monitoring the instantaneous sample temperature. The method is applied to a series of industrially relevant polymers, such as isotactic polypropylene, its copolymers and virgin and nucleated polyamide-6. Their crystallization behaviour during rapid cooling is discussed, with particular attention to the occurrence of polymorphism, which deeply impact material’s properties.

  12. Video-rate processing in tomographic phase microscopy of biological cells using CUDA.

    Science.gov (United States)

    Dardikman, Gili; Habaza, Mor; Waller, Laura; Shaked, Natan T

    2016-05-30

    We suggest a new implementation for rapid reconstruction of three-dimensional (3-D) refractive index (RI) maps of biological cells acquired by tomographic phase microscopy (TPM). The TPM computational reconstruction process is extremely time consuming, making the analysis of large data sets unreasonably slow and the real-time 3-D visualization of the results impossible. Our implementation uses new phase extraction, phase unwrapping and Fourier slice algorithms, suitable for efficient CPU or GPU implementations. The experimental setup includes an external off-axis interferometric module connected to an inverted microscope illuminated coherently. We used single cell rotation by micro-manipulation to obtain interferometric projections from 73 viewing angles over a 180° angular range. Our parallel algorithms were implemented using Nvidia's CUDA C platform, running on Nvidia's Tesla K20c GPU. This implementation yields, for the first time to our knowledge, a 3-D reconstruction rate higher than video rate of 25 frames per second for 256 × 256-pixel interferograms with 73 different projection angles (64 × 64 × 64 output). This allows us to calculate additional cellular parameters, while still processing faster than video rate. This technique is expected to find uses for real-time 3-D cell visualization and processing, while yielding fast feedback for medical diagnosis and cell sorting.

  13. Melting processes of oligomeric α and β isotactic polypropylene crystals at ultrafast heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Xiaojing [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); He, Xuehao, E-mail: xhhe@tju.edu.cn, E-mail: scjiang@tju.edu.cn [Department of Chemistry, School of Science, Tianjin University, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Jiang, Shichun, E-mail: xhhe@tju.edu.cn, E-mail: scjiang@tju.edu.cn [School of Material, Tianjin University, Tianjin 300072 (China)

    2014-02-07

    The melting behaviors of α (stable) and β (metastable) isotactic polypropylene (iPP) crystals at ultrafast heating rates are simulated with atomistic molecular dynamics method. Quantitative information about the melting processes of α- and β-iPP crystals at atomistic level is achieved. The result shows that the melting process starts from the interfaces of lamellar crystal through random dislocation of iPP chains along the perpendicular direction of lamellar crystal structure. In the melting process, the lamellar crystal gradually expands but the corresponding thickness decreases. The analysis shows that the system expansion lags behind the crystallinity decreasing and the lagging extents for α- and β-iPP are significantly different. The apparent melting points of α- and β-iPP crystals rise with the increase of the heating rate and lamellar crystal thickness. The apparent melting point of α-iPP crystal is always higher than that of β-iPP at differently heating rates. Applying the Gibbs-Thomson rule and the scaling property of the melting kinetics, the equilibrium melting points of perfect α- and β-iPP crystals are finally predicted and it shows a good agreement with experimental result.

  14. Multiple recharge processes to heterogeneous Mediterranean coastal aquifers and implications on recharge rates evolution in time

    Science.gov (United States)

    Santoni, S.; Huneau, F.; Garel, E.; Celle-Jeanton, H.

    2018-04-01

    Climate change is nowadays widely considered to have major effects on groundwater resources. Climatic projections suggest a global increase in evaporation and higher frequency of strong rainfall events especially in Mediterranean context. Since evaporation is synonym of low recharge conditions whereas strong rainfall events are more favourable to recharge in heterogeneous subsurface contexts, a lack of knowledge remains then on the real ongoing and future drinking groundwater supply availability at aquifers scale. Due to low recharge potential and high inter-annual climate variability, this issue is strategic for the Mediterranean hydrosystems. This is especially the case for coastal aquifers because they are exposed to seawater intrusion, sea-level rise and overpumping risks. In this context, recharge processes and rates were investigated in a Mediterranean coastal aquifer with subsurface heterogeneity located in Southern Corsica (France). Aquifer recharge rates from combining ten physical and chemical methods were computed. In addition, hydrochemical and isotopic investigations were carried out through a monthly two years monitoring combining major ions and stable isotopes of water in rain, runoff and groundwater. Diffuse, focused, lateral mountain system and irrigation recharge processes were identified and characterized. A predominant focused recharge conditioned by subsurface heterogeneity is evidenced in agreement with variable but highly favourable recharge rates. The fast water transfer from the surface to the aquifer implied by this recharge process suggests less evaporation, which means higher groundwater renewal and availability in such Mediterranean coastal aquifers.

  15. On the Values at Equilibrium and Rate Constants in Inter - Conversion Processes.

    Science.gov (United States)

    Olteanu, Octav

    2016-01-01

    Inter - conversion processes of labile molecules obey similar rules to those of reversible chemical reactions. Solving the corresponding linear differential systems is used along this work, as well as in the preceding version. The main purpose of the present mini revue paper is to recall, improve and correct some mathematical methods in determining the optimal values at equilibrium, and remarkable particular rate constants. This part was not proved correctly in my previous work. In my previous work, the proof of the equality of the concentrations of the main species at equilibrium was not correct. In the current manuscript, we use increasing velocity in order to obtain this first important result. To this aim, one applies Schwarz inequality and the case when equality occurs. In order to determine significant rate constants, we characterize these special values in terms of the norm of the linear operator defined by the matrix of the differential system. In my previous work, the normal probability density function was used. The latter method was not realistic. Increasing the velocity, one obtains equal optimal values of the concentrations at equilibrium. This method represents a patent in the field. Secondly, characterization of remarkable rate constants (which are also equal) is deduced. The optimal solutions are written explicitly. Under suitable conditions, the values at equilibrium and the rate constants are equal. The common value at equilibrium equals the common value of the rate constants.

  16. Academic and scientometric ratings in the process of science and education globalization: Socio-political implications

    Directory of Open Access Journals (Sweden)

    V G Ivanov

    2015-12-01

    Full Text Available The authors analyze some actual socio-political implications of the contemporary process of the broad recognition and expansion of global academic and scientometric ratings, as well as their impact on the state policy in the scientific and educational fields in the Russian Federation. The authors introduce the concept “charts power” as an important component of “soft power” of nation-states and international institutions for the most popular global academic and scientometric ratings can be used as an economic and foreign policy weapon. The article considers the leading academic ratings (Shanghai Academic Ranking of World Universities, Higher Education Index and QS World University Ranking and the key scietometric ratings (Web of Science and Scopus. The authors believe that the charts power of other countries represents a real and potential threat for the national security of the Russian Federation, and provide some recommendations to mitigate the challenges, for instance, to create and promote (in due course internationally a comparative index of trust to the international ratings including academic ones.

  17. Using r-process enhanced galaxies to estimate the neutron star merger rate at high redshift

    Science.gov (United States)

    Roederer, Ian

    2018-01-01

    The rapid neutron-capture process, or r-process, is one of the fundamental ways that stars produce heavy elements. I describe a new approach that uses the existence of r-process enhanced galaxies, like the recently discovered ultra-faint dwarf galaxy Reticulum II, to derive a rate for neutron star mergers at high redshift. This method relies on three assertions. First, several lines of reasoning point to neutron star mergers as a rare yet prolific producer of r-process elements, and one merger event is capable of enriching most of the stars in a low-mass dwarf galaxy. Second, the Local Group is cosmologically representative of the halo mass function at the mass scales of low-luminosity dwarf galaxies, and the volume that their progenitors spanned at high redshifts can be estimated from simulations. Third, many of these dwarf galaxies are extremely old, and the metals found in their stars today date from the earliest times at high redshift. These galaxies occupy a quantifiable volume of the Universe, from which the frequency of r-process enhanced galaxies can be estimated. This frequency may be interpreted as lower limit to the neutron star merger rate at a redshift (z ~ 5-10) that is much higher than is accessible to gravitational wave observatories. I will present a proof of concept demonstration using medium-resolution multi-object spectroscopy from the Michigan/Magellan Fiber System (M2FS) to recover the known r-process galaxy Reticulum II, and I will discuss future plans to apply this method to other Local Group dwarf galaxies.

  18. Application of the TDABC model in the logistics process using different capacity cost rates

    International Nuclear Information System (INIS)

    Afonso, Paulo; Santana, Alex

    2016-01-01

    Purpose: The understanding of logistics process in terms of costs and profitability is a complex task and there is a need of more research and applied work on these issues. In this research project, the concepts underlying Time-Driven Activity Based Costing (TDABC) have been used in the context of logistics costs. Design/methodology/approach: A Distribution Centre of wood and carpentry related materials has been studied. A multidisciplinary team has been composed to support the project including the researchers and three employees of the company responsible for accounting, logistics and warehousing. The design and implementation of the costing model asked for a deep understanding of the different tasks and processes that should be considered. Accordingly, a TDABC model for the logistics function was developed. Findings: The cost model presented here is supported on a series of time equations designed for the logistics function which allow the analysis and discussion of costs and profitability of different cost objects namely, products, clients, distribution channels, processes and activities. The cost of unused capacity and the effectiveness of logistics processes are also highlighted in this model. Research limitations/implications: In a case study, results and implications cannot be directly or immediately generalized. Nevertheless, the proposed time equations and cost model can be easily adapted to explain other types of logistics functions and it gives the foundations or other TDABC models with more than one capacity cost rate. Practical implications: The TDABC model developed in this case study can be used in similar cases and as a basis for the analysis of logistics costs in other logistics processes. Furthermore, managers can rely on the proposed approach to analyze products’ profitability and logistics cost structure. Originality/value: In this case, different capacity cost rates were computed in order to reflect appropriately the logistics function which

  19. Application of the TDABC model in the logistics process using different capacity cost rates

    Directory of Open Access Journals (Sweden)

    Paulo Afonso

    2016-12-01

    Full Text Available Purpose: The understanding of logistics process in terms of costs and profitability is a complex task and there is a need of more research and applied work on these issues. In this research project, the concepts underlying Time-Driven Activity Based Costing (TDABC have been used in the context of logistics costs. Design/methodology/approach: A Distribution Centre of wood and carpentry related materials has been studied. A multidisciplinary team has been composed to support the project including the researchers and three employees of the company responsible for accounting, logistics and warehousing. The design and implementation of the costing model asked for a deep understanding of the different tasks and processes that should be considered. Accordingly, a TDABC model for the logistics function was developed. Findings: The cost model presented here is supported on a series of time equations designed for the logistics function which allow the analysis and discussion of costs and profitability of different cost objects namely, products, clients, distribution channels, processes and activities. The cost of unused capacity and the effectiveness of logistics processes are also highlighted in this model. Research limitations/implications: In a case study, results and implications cannot be directly or immediately generalized. Nevertheless, the proposed time equations and cost model can be easily adapted to explain other types of logistics functions and it gives the foundations or other TDABC models with more than one capacity cost rate. Practical implications: The TDABC model developed in this case study can be used in similar cases and as a basis for the analysis of logistics costs in other logistics processes. Furthermore, managers can rely on the proposed approach to analyze products’ profitability and logistics cost structure.  Originality/value: In this case, different capacity cost rates were computed in order to reflect appropriately the

  20. Monitoring granulation rate processes using three PAT tools in a pilot-scale fluidized bed.

    Science.gov (United States)

    Tok, Ai Tee; Goh, Xueping; Ng, Wai Kiong; Tan, Reginald B H

    2008-01-01

    The purpose of this research was to analyze and compare the responses of three Process Analytical Technology (PAT) techniques applied simultaneously to monitor a pilot-scale fluidized bed granulation process. Real-time measurements using focused beam reflectance measurement (Lasentec FBRM) and near-infra red spectroscopy (Bruker NIR) were taken by inserting in-line probes into the fluidized bed. Non-intrusive acoustic emission measurements (Physical Acoustic AE) were performed by attaching piezoelectric sensors on the external wall of the fluidized bed. Powder samples were collected at regular intervals during the granulation process and characterized offline using laser diffraction, scanning electron microscopy, stereo-optical microscopy and loss on drying method. PAT data comprising chord length distribution and chord count (from FBRM), absorption spectra (from NIR) and average signal levels and counts (from AE) were compared with the particle properties measured using offline samples. All three PAT techniques were able to detect the three granulation regimes or rate processes (wetting and nucleation, consolidation and growth, breakage) to varying degrees of sensitivity. Being dependent on optical signals, the sensitivities of the FBRM and NIR techniques were susceptible to fouling on probe windows. The AE technique was sensitive to background fluidizing air flows and external interferences. The sensitivity, strengths and weaknesses of the PAT techniques examined may facilitate the selection of suitable PAT tools for process development and scale-up studies.

  1. Stellar neutron capture rates – key data for the s process

    Directory of Open Access Journals (Sweden)

    Käppeler F.

    2013-12-01

    Full Text Available Neutron reactions are responsible for the formation of the elements heavier than iron. The corresponding scenarios relate to the He- and C- burning phases of stellar evolution (s process and to supernova explosions (r and p processes. The s process, which is characterized by low neutron densities, operates in or near the valley of β stability and has produced about half of the elemental abundances between Fe and Bi in the solar system and in the Universe. Because the s abundances are essentially determined by the (n, γ cross sections along the reaction path, accurate neutron data constitute the key input for s process studies. Important constraints for the physical conditions at the stellar sites can be inferred by comparison of the abundance patterns from current s-process models with solar system material or presolar grains. The experimental methods for the determination of stellar (n, γ rates are outlined at the example of recent cross section measurements and remaining quests will be discussed with respect to existing laboratory neutron sources and new developments.

  2. Coding efficiency of fly motion processing is set by firing rate, not firing precision.

    Directory of Open Access Journals (Sweden)

    Deusdedit Lineu Spavieri

    Full Text Available To comprehend the principles underlying sensory information processing, it is important to understand how the nervous system deals with various sources of perturbation. Here, we analyze how the representation of motion information in the fly's nervous system changes with temperature and luminance. Although these two environmental variables have a considerable impact on the fly's nervous system, they do not impede the fly to behave suitably over a wide range of conditions. We recorded responses from a motion-sensitive neuron, the H1-cell, to a time-varying stimulus at many different combinations of temperature and luminance. We found that the mean firing rate, but not firing precision, changes with temperature, while both were affected by mean luminance. Because we also found that information rate and coding efficiency are mainly set by the mean firing rate, our results suggest that, in the face of environmental perturbations, the coding efficiency is improved by an increase in the mean firing rate, rather than by an increased firing precision.

  3. Site selection and rating process, and criteria for a social and political approach

    International Nuclear Information System (INIS)

    Boisseson, P. de; David, J.F.

    1998-01-01

    Full text of publication follows: sensitive projects have been for long the problem of engineers and geologists, which tried to exert a kind of mono-cultural approach upon decisions regarding: a type of technical solution, a choice for a location. Experience drawn from various projects shows that public choices must be targeted to public acceptance and not only to hard-science community. Ways of rating site for sensitive projects according to criteria derived from social and political approach have been set up to provide global advice to decision makers. Bases are found among: socio economical statistics (type and rate of employment), land use regulations, history of public and local acceptance of former projects or public regulations. Representations can be drawn through social modeling and qualitative analysis. They can be of an utmost importance in decision making process. (authors)

  4. On the Pervasiveness of Long Range Memory Processes in Daily High School Attendance Rates.

    Science.gov (United States)

    Koopmans, Matthijs

    2018-04-01

    Few educational researchers or practitioners would question that high school attendance is an important mediator in the causal network that is used to explain academic achievement, yet attendance remains under-researched. The New York City Department of Education (NYCDOE) has created an opportunity to examine the longitudinal trends and dependencies in daily attendance rates as it created a repository of daily attendance rates for all its schools, starting in 2004. The present analysis examines the dynamical patterns in daily attendance rates over a ten-year period (Sept. 2004 - June 2014) in six small high schools and ten large ones. As was done in previous work, this analysis systematically distinguishes short range, seasonal and long range dependencies in the data using time series analysis. Seasonal cycles are predictable (here, fluctuation by days of the week), the long range dependencies indicate cycles that are unpredictable, suggestive of more complex dynamical processes, such as self-similarity, self-organized criticality and scale invariance, features that are difficult to detect by school building personnel, but are important aspects of the systems' behavior. Seasonal cycles were found in three of the nine large schools and in all six small ones. Significant long range dependencies (Hurst exponent) were found in all large schools and all but one of the small ones. The pervasiveness of the long range processes over and above the seasonal cycles is striking, and may suggest an adaptability of these systems to fluctuations in the exogenous processes that find their expression in daily attendance behavior (e.g., parental involvement). However, this latter interpretation is in need of further empirical support.

  5. Ring Laser Gyro-based Digital Processing Technique for Detecting Rotation Rate over Short Time Intervals

    Directory of Open Access Journals (Sweden)

    V. N. Enin

    2017-01-01

    Full Text Available The article investigates capabilities of digital techniques to improve measurement accuracy of dithering ring laser gyro (DRLG in detecting constant rotation rate over short time intervals. An array of the GL-1 device output within a LG triad to measure the vertical component of the angular rate of rotation of the Earth in the laboratory setting is selected as the object of study. The selected time of a single measurement is 2 minutes, and as a full standard deviation error of measurement is selected the magnitude at least 0.002 "/ min. The objective of this study is to develop and underpin a new effective technique of LG digital information processing to enable providing an appropriate accuracy to meet modern requirements with reducing measurement time of a constant rate Ωz component. The specific objectives are the comparative analysis of the precision capabilities of the known techniques over limited measurement time intervals, development and support of new, more efficient technique of digital information processing of dithering ring LG, and experimental verification and evaluation of effectiveness of the technique proposed. The article presents a comparative error analysis of practically applied digital techniques such a simple averaging method, Hamming method, and method of "conditional sample of regression lines" with the proposed technique of "recognition of the output signal of the image N". To compare the techniques were used the real digital processing device output data taken at a frequency of 400 Hz over 94 two-minute measurement intervals after the device has been switched on. The proposed LG output image recognition technique enables us to reach about three times higher measuring accuracy over two-minute interval as compared to the known techniques.

  6. Detecting Randomness: the Sensitivity of Statistical Tests to Deviations from a Constant Rate Poisson Process

    Science.gov (United States)

    Michael, A. J.

    2012-12-01

    Detecting trends in the rate of sporadic events is a problem for earthquakes and other natural hazards such as storms, floods, or landslides. I use synthetic events to judge the tests used to address this problem in seismology and consider their application to other hazards. Recent papers have analyzed the record of magnitude ≥7 earthquakes since 1900 and concluded that the events are consistent with a constant rate Poisson process plus localized aftershocks (Michael, GRL, 2011; Shearer and Stark, PNAS, 2012; Daub et al., GRL, 2012; Parsons and Geist, BSSA, 2012). Each paper removed localized aftershocks and then used a different suite of statistical tests to test the null hypothesis that the remaining data could be drawn from a constant rate Poisson process. The methods include KS tests between event times or inter-event times and predictions from a Poisson process, the autocorrelation function on inter-event times, and two tests on the number of events in time bins: the Poisson dispersion test and the multinomial chi-square test. The range of statistical tests gives us confidence in the conclusions; which are robust with respect to the choice of tests and parameters. But which tests are optimal and how sensitive are they to deviations from the null hypothesis? The latter point was raised by Dimer (arXiv, 2012), who suggested that the lack of consideration of Type 2 errors prevents these papers from being able to place limits on the degree of clustering and rate changes that could be present in the global seismogenic process. I produce synthetic sets of events that deviate from a constant rate Poisson process using a variety of statistical simulation methods including Gamma distributed inter-event times and random walks. The sets of synthetic events are examined with the statistical tests described above. Preliminary results suggest that with 100 to 1000 events, a data set that does not reject the Poisson null hypothesis could have a variability that is 30% to

  7. Experimental verification of preset time count rate meters based on adaptive digital signal processing algorithms

    Directory of Open Access Journals (Sweden)

    Žigić Aleksandar D.

    2005-01-01

    Full Text Available Experimental verifications of two optimized adaptive digital signal processing algorithms implemented in two pre set time count rate meters were per formed ac cording to appropriate standards. The random pulse generator realized using a personal computer, was used as an artificial radiation source for preliminary system tests and performance evaluations of the pro posed algorithms. Then measurement results for background radiation levels were obtained. Finally, measurements with a natural radiation source radioisotope 90Sr-90Y, were carried out. Measurement results, con ducted without and with radio isotopes for the specified errors of 10% and 5% showed to agree well with theoretical predictions.

  8. On-line statistical processing of radiation detector pulse trains with time-varying count rates

    International Nuclear Information System (INIS)

    Apostolopoulos, G.

    2008-01-01

    Statistical analysis is of primary importance for the correct interpretation of nuclear measurements, due to the inherent random nature of radioactive decay processes. This paper discusses the application of statistical signal processing techniques to the random pulse trains generated by radiation detectors. The aims of the presented algorithms are: (i) continuous, on-line estimation of the underlying time-varying count rate θ(t) and its first-order derivative dθ/dt; (ii) detection of abrupt changes in both of these quantities and estimation of their new value after the change point. Maximum-likelihood techniques, based on the Poisson probability distribution, are employed for the on-line estimation of θ and dθ/dt. Detection of abrupt changes is achieved on the basis of the generalized likelihood ratio statistical test. The properties of the proposed algorithms are evaluated by extensive simulations and possible applications for on-line radiation monitoring are discussed

  9. High-throughput sequencing-based microbial characterization of size fractionated biomass in an anoxic anammox reactor for low-strength wastewater at low temperatures.

    Science.gov (United States)

    Liu, Wenru; Yang, Dianhai; Chen, Wenjing; Gu, Xiao

    2017-05-01

    The microbial characterization of three size-fractionated sludge obtained from a suspended-growth anoxic anammox reactor treating low-strength wastewater at low temperatures were investigated by using high-throughput sequencing. Particularly, the spatial variability in relative abundance of microorganisms involved in nitrogen metabolism were analyzed in detail. Results showed that population segregation did occur in the reactor. It was found, for the first time, that the genus Nitrotoga was enriched only in large granules (>400μm). Three anammox genus including Candidatus Jettenia, Brocadia and Kuenenia were detected. Among them, Candidatus Brocadia and Kuenenia preferred to grow in large-sized granules (>400μm), whereas Candidatus Jettenia dominated in small- and moderate-sized sludge (biomass. However, further studies are required to identify the activity of different-size sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Auditory detection of an increment in the rate of a random process

    International Nuclear Information System (INIS)

    Brown, W.S.; Emmerich, D.S.

    1994-01-01

    Recent experiments have presented listeners with complex tonal stimuli consisting of components with values (i.e., intensities or frequencies) randomly sampled from probability distributions [e.g., R. A. Lutfi, J. Acoust. Soc. Am. 86, 934--944 (1989)]. In the present experiment, brief tones were presented at intervals corresponding to the intensity of a random process. Specifically, the intervals between tones were randomly selected from exponential probability functions. Listeners were asked to decide whether tones presented during a defined observation interval represented a ''noise'' process alone or the ''noise'' with a ''signal'' process added to it. The number of tones occurring in any observation interval is a Poisson variable; receiver operating characteristics (ROCs) arising from Poisson processes have been considered by Egan [Signal Detection Theory and ROC Analysis (Academic, New York, 1975)]. Several sets of noise and signal intensities and observation interval durations were selected which were expected to yield equivalent performance. Rating ROCs were generated based on subjects' responses in a single-interval, yes--no task. The performance levels achieved by listeners and the effects of intensity and duration are compared to those predicted for an ideal observer

  11. Spatial analysis of ambient gamma dose equivalent rate data by means of digital image processing techniques.

    Science.gov (United States)

    Szabó, Katalin Zsuzsanna; Jordan, Gyozo; Petrik, Attila; Horváth, Ákos; Szabó, Csaba

    2017-01-01

    A detailed ambient gamma dose equivalent rate mapping based on field measurements at ground level and at 1 m height was carried out at 142 sites in 80 × 90 km area in Pest County, Hungary. Detailed digital image processing analysis was carried out to identify and characterise spatial features such as outlying points, anomalous zones and linear edges in a smoothed TIN interpolated surface. The applied method proceeds from the simple shaded relief model and digital cross-sections to the more complex gradient magnitude and gradient direction maps, 2nd derivative profile curvature map, relief map and lineament density map. Each map is analysed for statistical characteristics and histogram-based image segmentation is used to delineate areas homogeneous with respect to the parameter values in these maps. Assessment of spatial anisotropy is implemented by 2D autocorrelogram and directional variogram analyses. The identified spatial features are related to underlying geological and tectonic conditions using GIS technology. Results show that detailed digital image processing is efficient in revealing the pattern present in field-measured ambient gamma dose equivalent rates and they are related to regional scale tectonic zones and surface sedimentary lithological conditions in the study area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Faunal burrows alter the diversity, abundance, and structure of AOA, AOB, anammox and n-damo communities in coastal mangrove sediments

    OpenAIRE

    Chen, Jing; Gu, Ji-Dong

    2017-01-01

    In the present work, the diversity, community structures, and abundances of aerobic ammonia-oxidizing archaea (AOA) and bacteria (AOB), anaerobic ammonium-oxidizing (anammox) bacteria, and denitrifying anaerobic methane oxidization (n-damo) bacteria were unraveled in the bioturbated areas of the coastal Mai Po mangrove sediments. Results indicated that the bioturbation by burrowing in mangrove sediments was associated with higher concentration of NH4+ but lower concentrations of both NO2− and...

  13. Sedimentation rates in relation to sedimentary processes of the Yangtze Estuary, China

    Science.gov (United States)

    Wei, Taoyuan; Chen, Zhongyuan; Duan, Lingyun; Gu, Jiawei; Saito, Yoshiki; Zhang, Weiguo; Wang, Yonghong; Kanai, Yutaka

    2007-01-01

    Radioisotope analysis and Digital Elevation Model (DEM) method were combined to examine sedimentation rates and associated sedimentary processes in the Yangtze River Estuary. The major depocenter is validated at the delta front sedimentary facies above the normal wave base (NWB), where accumulation exceeds erosion. This alternated sedimentation does not accommodate Pb-210 and Cs-137 measurement, although sedimentation rates of less than 0.2-5.0 cm yr -1 were recorded in the fine-grained (silty) sediments, which were interbedded with coarse-grained (sandy) sediments. However, historical DEM data provide more detailed information on sedimentation in the delta front facies, where accumulation is dominant in the sandy shoals (1.73-8.30 cm yr -1) and delta front slope (5.22 cm yr -1) facies. The DEM data also show that erosion (1.61-7.32 cm yr -1) dominates in the northern estuarine distributaries, and accumulation (3.01-4.97 cm yr -1) prevails in the southern ones, primarily owing to the superimposed runoff and ebb tidal currents. Pb-210 and Cs-137 measurements reveal sedimentation rate from 2.0 cm yr -1 to 6.3-6.6 cm yr -1 in the delta front slope facies, which progressively decreases to erosion in the delta front slope and prodelta facies, although accumulation predominates there. The present sedimentological database will be useful for estuarine environmental assessment after the Three-Gorges Dam is completed in 2009.

  14. [Achieve single-stage autotrophic biological nitrogen removal process by controlling the concentration of free ammonia].

    Science.gov (United States)

    Ji, Li-Li; Yang, Zhao-Hui; Xu, Zheng-Yong; Li, Xiao-Jiang; Tang, Zhi-Gang; Deng, Jiu-Hu

    2011-01-01

    Through controlling the concentration of free ammonia in the sequencing batch reactor (SBR), the single-stage autotrophic biological nitrogen removal process was achieved, including partial nitrification and anaerobic ammonium oxidation. The experiment was completed via two steps, the enrichment of nitrite bacteria and the inoculation of the mixture of anammox biomass. The operating temperature in the SBR was (31 +/- 2) degrees C. During the step of the enrichment of nitrite bacteria, pH was about 7.8. Changes of FA concentration were achieved by controlling the concentration of influent NH4(+) -N(56-446 mg x L(-1)), in order to inhibit and eliminate the nitrate bacteria. The activity tests of the sludge, 55d after enrichment, showed strong activity of aerobic ammonium oxidation [2.91 kg x (kg x d)(-1)] and low activity of nitrite oxidation [0.03 kg x(kg x d)(-1)]. During the inoculation of the mixture of anammox biomass, changes of FA concentration were achieved by controlling the concentration of influent NH4(+) -N and pH. As the inoculation of anammox biomass, abundant of bacteria and nutrient content were into the reactor and there kept high activity of aerobic ammonium oxidation [2.83 kg x (kg x d)(-1)] and a certain activity of nitrite oxidation, at the same time, the activity of anammox and heterotrophic denitrification reached 0.65 kg x (kg x d)(-1) and 0.11 kg x (kg x d)(-1), respectively.

  15. High-energy high-rate processing of high-temperature metal-matrix composites

    International Nuclear Information System (INIS)

    Persad, C.; Raghunathan, S.; Lee, B.H.; Bourell, D.L.; Eliezer, Z.; Marcus, H.L.

    1988-01-01

    Advances in kinetic energy storage devices have opened up a new approach to powder processing of high temperature composites. The processing consists of internal heating of a customized powder blend by a fast electrical discharge of homopolar generator. The high-energy high rate IMJ in 1s pulse permits rapid heating of a conducting powder in a cold wall die. This short time at temperature approach offers the opportunity to control phase transformations and the degree of microstructural coarsening not readily possible using standard powder processing approaches. This paper describes the consolidation results of two high temperature composite materials, (W-Ni-Fe)B 4 C and (Ti 3 Al + Nb)/SiC. The focus of this study was the identification of the reaction products formed at the matrix/reinforcement interface as a function of input energy and applied stress. Input energies beyond a threshold value for each system were required to produce detectable reaction products. In the (W-Ni-Fe)/B 4 C system, the reaction products formed at 4000 kj/kg input energy under 420 MPa applied stress were a series of complex carbides and borides including W 2 C,FeWb,Fe 3 C,Fe 6 W 6 C and Ni 4 B 3 . The intermetallic Fe 7 W 6 was also observed. In the (Ti 3 Al + Nb)SiC System, the reaction products observed at 3400 kj/kg and 210 MPa were TiC and TiSi 2

  16. Relative growth rates of three woody legumes: implications in the process of ecological invasion

    Directory of Open Access Journals (Sweden)

    J. A. Crisóstomo

    2007-03-01

    Full Text Available Acacia longifolia, an Australian leguminous tree, is one of the main invasive plant species in the coast of Portugal and a major threat to the native vegetation in the Reserva Natural das Dunas de São Jacinto. With the establishment of this exotic species, other native woody leguminous species such as Cytisus grandiflorus and Ulex europaeus have been displaced from their original areas. Several factors are involved in the process of biological invasion by exotic species. Plant physiology and development, characteristic of each species, can give certain advantages in the establishment and colonization of new areas. We tested if there are differences in the Relative Growth Rate (RGR of the exotic and native species because this could be relevant in the first stages of the invasion process. Our results showed that A. longifolia was the species with lowest RGR. Therefore, other factors apart from RGR might explain the invasion of coastal dunes by this species. We propose that A. longifolia might be a better competitor than the two native legumes and that this process might be mediated by the interaction with soil organisms.

  17. Evolution of the fracture process zone in high-strength concrete under different loading rates

    Directory of Open Access Journals (Sweden)

    Cámara M.

    2010-06-01

    Full Text Available For cementitious materials, the inelastic zone around a crack tip is termed as fracture process zone (FPZ and dominated by complicated mechanism, such as microcracking, crack deflection, bridging, crack face friction, crack tip blunting by voids, crack branching, and so on. Due to the length of the FPZ is related with the characteristic length of the cementitious materials, the size, extent and location of the FPZ has been the object of countless research efforts for several decades. For instance, Cedolin et al. [1] have used an optical method based on the moiré interferometry to determine FPZ in concrete. Castro-Montero et al. [2] have applied the method of holographic interferometry to mortar to study the extension of the FPZ. The advantage of the interferometry method is that the complete FPZ can be directly observed on the surface of the sample. Swartz et al. [3] has adopted the dye penetration technique to illustrate the changing patterns observed as the crack progress from the tensile side to the compression side of the beam. Moreover, acoustic emission (AE is also an experimental technique well suited for monitoring fracture process. Haidar et al. [4] and Maji et al. [5] have studied the relation between acoustic emission characteristics and the properties of the FPZ. Compared with the extensive research on properties of the FPZ under quasi-static loading conditions, much less information is available on its dynamic characterization, especially for high-strength concrete (HSC. This paper presents the very recent results of an experimental program aimed at disclosing the loading rate effect on the size and velocity of the (FPZ in HSC. Eighteen three-point bending specimens were conducted under a wide range of loading rates from from 10-4 mm/s to 103 mm/s using either a servo-hydraulic machine or a self-designed drop-weight impact device. The beam dimensions were 100 mm 100 mm in cross section, and 420 mm in length. The initial notch

  18. Effects of stochastic interest rates in decision making under risk: A Markov decision process model for forest management

    Science.gov (United States)

    Mo Zhou; Joseph Buongiorno

    2011-01-01

    Most economic studies of forest decision making under risk assume a fixed interest rate. This paper investigated some implications of this stochastic nature of interest rates. Markov decision process (MDP) models, used previously to integrate stochastic stand growth and prices, can be extended to include variable interest rates as well. This method was applied to...

  19. The rate of food processing in the Oystercatcher : Food intake and energy expenditure constrained by a digestive bottleneck

    NARCIS (Netherlands)

    Kersten, M.

    1. Whether food intake is determined by the maximum rate at which animals can collect food, or by the rate at which this food can be processed, will strongly affect the organization of their behaviour. We investigated whether the digestive system imposes a constraint on (I) instantaneous rate of

  20. PREFACE: 6th International Workshop on Multi-Rate Processes and Hysteresis (MURPHYS2012)

    Science.gov (United States)

    Dimian, Mihai; Rachinskii, Dmitrii

    2015-02-01

    The International Workshop on Multi-Rate Processes and Hysteresis (MURPHYS) conference series focuses on multiple scale systems, singular perturbation problems, phase transitions and hysteresis phenomena occurring in physical, biological, chemical, economical, engineering and information systems. The 6th edition was hosted by Stefan cel Mare University in the city of Suceava located in the beautiful multicultural land of Bukovina, Romania, from May 21 to 24, 2012. This continued the series of biennial multidisciplinary conferences organized in Cork, Ireland from 2002 to 2008 and in Pécs, Hungary in 2010. The MURPHYS 2012 Workshop brought together more than 50 researchers in hysteresis and multi-scale phenomena from the United State of America, the United Kingdom, France, Germany, Italy, Ireland, Czech Republic, Hungary, Greece, Ukraine, and Romania. Participants shared and discussed new developments of analytical techniques and numerical methods along with a variety of their applications in various areas, including material sciences, electrical and electronics engineering, mechanical engineering and civil structures, biological and eco-systems, economics and finance. The Workshop was sponsored by the European Social Fund through Sectoral Operational Program Human Resources 2007-2013 (PRO-DOCT) and Stefan cel Mare University, Suceava. The Organizing Committee was co-chaired by Mihai Dimian from Stefan cel Mare University, Suceava (Romania), Amalia Ivanyi from the University of Pecs (Hungary), and Dmitrii Rachinskii from the University College Cork (Ireland). All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing. The Guest Editors wish to place on record their sincere gratitude to Miss Sarah Toms for the assistance she provided

  1. Dynamic testing at high strain rates of an ultrafine-grained magnesium alloy processed by ECAP

    Energy Technology Data Exchange (ETDEWEB)

    Li, B., E-mail: bli@jhu.edu [Center for Advanced Metallic and Ceramic Systems, Johns Hopkins University, Baltimore, MD 21218 (United States); Joshi, S. [Center for Advanced Metallic and Ceramic Systems, Johns Hopkins University, Baltimore, MD 21218 (United States); Department of Mechanical Engineering, National University of Singapore, Singapore 117576 (Singapore); Azevedo, K.; Ma, E.; Ramesh, K.T. [Center for Advanced Metallic and Ceramic Systems, Johns Hopkins University, Baltimore, MD 21218 (United States); Figueiredo, R.B. [Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1453 (United States); Department of Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Langdon, T.G. [Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1453 (United States); Department of Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Materials Research Group, School of Engineering Sciences, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2009-08-20

    A ZK60 magnesium alloy was processed by equal-channel angular pressing (ECAP) at 473 K to produce a grain size of {approx}0.8 {mu}m and it was then tested under dynamic conditions at strain rates up to 4.0 x 10{sup 3} s{sup -1} using a split-Hopkinson bar. The stress-strain curves in dynamic testing exhibited upwards concave curvature suggesting the occurrence of twinning. Examination by transmission electron microscopy showed that dislocation slip played a major role in the flow behavior with dislocation accumulation as the main source of work hardening. An identification of Burgers vectors revealed the extensive presence of prismatic dislocations. Rod-shaped Mg{sub 1}(Zn,Zr){sub 1} precipitates present in the as-received alloy become fragmented and overaged during ECAP.

  2. Bidding process in online auctions and winning strategy: Rate equation approach

    Science.gov (United States)

    Yang, I.; Kahng, B.

    2006-06-01

    Online auctions have expanded rapidly over the last decade and have become a fascinating new type of business or commercial transaction in this digital era. Here we introduce a master equation for the bidding process that takes place in online auctions. We find that the number of distinct bidders who bid k times up to the t th bidding progresses, called the k -frequent bidder, seems to scale as nk(t)˜tk-2.4 . The successfully transmitted bidding rate by the k -frequent bidder is likely to scale as qk(t)˜k-1.4 , independent of t for large t . This theoretical prediction is close to empirical data. These results imply that bidding at the last moment is a rational and effective strategy to win in an eBay auction.

  3. Utilization of electromigration in civil and environmental engineering--processes, transport rates and matrix changes.

    Science.gov (United States)

    Ottosen, Lisbeth M; Christensen, Iben V; Rorig-Dalgård, Inge; Jensen, Pernille E; Hansen, Henrik K

    2008-07-01

    Electromigration (movement of ions in an applied electric field) is utilized for supply or extraction of ions from various porous materials within both civil and environmental engineering. In civil engineering, most research has been conducted on the removal of chlorides from concrete to hinder reinforcement corrosion while in environmental engineering remediation of heavy metal polluted soil is the issue most studied. Never the less, experiments have been conducted with utilization for several other materials and purposes within both engineering fields. Even though there are many topics of common interest in the use of electromigration for the two fields, there is no tradition for collaboration. The present paper is a review with the aim of pointing out areas of shared interest. Focus is laid on the purposes of the different processes, transport rates of various ions in different materials and on changes in the matrix itself. Desorption and dissolution of the target elements into ionic form is a key issue to most of the processes, and can be the limiting step. The removal rate is generally below 1 cm day(- 1), but it can be much less than 1 mm day(- 1) when desorption is slow and insufficient. Matrix changes occurs under the action of the applied electric field and it includes both physico-chemical and hydrological changes. Some of the solid phases is weathered and new can be formed. Increased fundamental understanding of the effects and side effects, when applying the electric field to a porous material, can lead to improvement of the known technologies and possibly to new applications.

  4. Regional processes in mangrove ecosystems: Spatial scaling relationships, biomass, and turnover rates following catastrophic disturbance

    Science.gov (United States)

    Ward, G.A.; Smith, T. J.; Whelan, K.R.T.; Doyle, T.W.

    2006-01-01

    Physiological processes and local-scale structural dynamics of mangroves are relatively well studied. Regional-scale processes, however, are not as well understood. Here we provide long-term data on trends in structure and forest turnover at a large scale, following hurricane damage in mangrove ecosystems of South Florida, U.S.A. Twelve mangrove vegetation plots were monitored at periodic intervals, between October 1992 and March 2005. Mangrove forests of this region are defined by a -1.5 scaling relationship between mean stem diameter and stem density, mirroring self-thinning theory for mono-specific stands. This relationship is reflected in tree size frequency scaling exponents which, through time, have exhibited trends toward a community average that is indicative of full spatial resource utilization. These trends, together with an asymptotic standing biomass accumulation, indicate that coastal mangrove ecosystems do adhere to size-structured organizing principles as described for upland tree communities. Regenerative dynamics are different between areas inside and outside of the primary wind-path of Hurricane Andrew which occurred in 1992. Forest dynamic turnover rates, however, are steady through time. This suggests that ecological, more-so than structural factors, control forest productivity. In agreement, the relative mean rate of biomass growth exhibits an inverse relationship with the seasonal range of porewater salinities. The ecosystem average in forest scaling relationships may provide a useful investigative tool of mangrove community biomass relationships, as well as offer a robust indicator of general ecosystem health for use in mangrove forest ecosystem management and restoration. ?? Springer 2006.

  5. Investigation of fatigue crack growth rate of Al 5484 ultrafine grained alloy after ECAP process

    Energy Technology Data Exchange (ETDEWEB)

    Brynk, Tomasz; Rasinski, Marcin; Pakiela, Zbigniew; Kurzydlowski, Krzysztof J. [Faculty of Materials Science and Engineering, Warsaw University of Technology (Poland); Olejnik, Lech [Faculty of Production Engineering, Warsaw University of Technology (Poland)

    2010-05-15

    During the last decade equal-channel angular pressing (ECAP) has emerged as a widely used fabrication route of ultrafine-grained (UFG) metals and alloys. Enhanced mechanical properties of UFG materials produced by severe plastic deformation, with a grain size smaller than 1 {mu}m, have been reported in a large number of publications. However, the higher strength does not imply higher resistance to fatigue both high- and low-cyclic. In fact, due to reduced plasticity, higher fatigue crack propagation rates are reported for UFG materials, particularly in low-amplitude range. The aim of this work was to investigate fatigue crack propagation in samples of Al 5483 alloy subjected to ECAP treatment. Because of small dimensions of the coupons processed by ECAP, non-standard, mini-samples were used in a crack propagation tests. Two test procedures were used to estimate stress intensity factor (K). The first was based on optical measurements of crack length from images recorded during the test. The second method was based on digital image correlation (DIC), which was used to determine K value directly from displacement field near the crack tip. Comparison of these two methods is made and the relationship between the intensity of ECAP process (measured in terms of the number of ECAP passes) and fatigue crack propagation rates proposed. In addition to fatigue resistance, the results of tensile tests carried out with mini-samples are presented. Applicability of such samples in the investigations of the mechanical properties of UFG materials is discussed. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Hydrothermal decomposition of industrial jarosite in alkaline media: The rate determining step of the process kinetics

    Directory of Open Access Journals (Sweden)

    González-Ibarra A.A.

    2016-01-01

    Full Text Available This work examines the role of NaOH and Ca(OH2 on the hydrothermal decomposition of industrial jarosite deposited by a Mexican company in a tailings dam. The industrial jarosite is mainly composed by natrojarosite and contains 150 g Ag/t, showing a narrow particle size distribution, as revealed by XRD, fire assay, SEM-EDS and laser-diffraction analysis. The effect of the pH, when using NaOH or Ca(OH2 as alkalinizing agent was studied by carrying out decomposition experiments at different pH values and 60°C in a homogeneous size particle system (pH = 8, 9, 10 and 11 and in a heterogeneous size particle system (pH = 11. Also, the kinetic study of the process and the controlling step of the decomposition reaction when NaOH and Ca(OH2 are used was determined by fitting the data obtained to the shrinking core model for spherical particles of constant size. These results, supported by chemical (EDS, morphological (SEM and mapping of elements (EDS analysis of a partially reacted jarosite particle allowed to conclude that when NaOH is used, the process kinetics is controlled by the chemical reaction and when Ca(OH2 is used, the rate determining step is changed to a diffusion control through a layer of solid products.

  7. Geochemical information and isotopic ratios in pinpointing the rates of contamination processes generated at mine sites

    Science.gov (United States)

    Turunen, Kaisa; Kittilä, Anniina; Backnäs, Soile; Pasanen, Antti; Hendriksson, Nina

    2015-04-01

    The isotopic composition of water is an important fingerprinting method for tracing recharge sources, distribution processes and possible hydraulic connections of mine waters. However, since, the isotopes alone do not indicate the contamination derived from mining activities; also a set of geochemical analysis of harmful substance in water is acquired. This complex approach will allow a detailed insight in migration of potentially harmful substances, their reactions, mixing and dilution in ground and surface waters. The data can be applied also when comparing geogenic and anthropogenic emissions. Isotopic methods are rather new approach to estimate mining related emissions in Finland and thus, a novel approach of isotopic methods for investigation and monitoring of migration of harmful substances from mine sites are tested in two mine sites in Finland. The aim of this study is to assess the emission sources, flow paths and interaction between mine waters, groundwater and surface waters. A set of isotopic data, including S, Li, Mg, U, Sr, Pb, O, and H, will be combined with chemical information and physical parameters of water in order to assess the source and extent of possible contamination as well as the rates of processes that generate or at best attenuate the contamination. The results obtained from water analyses and field measurements will be used in hydrogeochemical modelling for the prediction of chemical transformation and long-term impacts of mining at study site and its surroundings.

  8. An operational protocol for facilitating start-up of single-stage autotrophic nitrogen-removing reactors based on process stoichiometry

    DEFF Research Database (Denmark)

    Mutlu, Ayten Gizem; Vangsgaard, Anna Katrine; Sin, Gürkan

    2013-01-01

    Start-up and operation of single-stage nitritation–anammox sequencing batch reactors (SBRs) for completely autotrophic nitrogen removal can be challenging and far from trivial. In this study, a step-wise procedure is developed based on stoichiometric analysis of the process performance from...

  9. Automatic processing of high-rate, high-density multibeam echosounder data

    Science.gov (United States)

    Calder, B. R.; Mayer, L. A.

    2003-06-01

    Multibeam echosounders (MBES) are currently the best way to determine the bathymetry of large regions of the seabed with high accuracy. They are becoming the standard instrument for hydrographic surveying and are also used in geological studies, mineral exploration and scientific investigation of the earth's crustal deformations and life cycle. The significantly increased data density provided by an MBES has significant advantages in accurately delineating the morphology of the seabed, but comes with the attendant disadvantage of having to handle and process a much greater volume of data. Current data processing approaches typically involve (computer aided) human inspection of all data, with time-consuming and subjective assessment of all data points. As data rates increase with each new generation of instrument and required turn-around times decrease, manual approaches become unwieldy and automatic methods of processing essential. We propose a new method for automatically processing MBES data that attempts to address concerns of efficiency, objectivity, robustness and accuracy. The method attributes each sounding with an estimate of vertical and horizontal error, and then uses a model of information propagation to transfer information about the depth from each sounding to its local neighborhood. Embedded in the survey area are estimation nodes that aim to determine the true depth at an absolutely defined location, along with its associated uncertainty. As soon as soundings are made available, the nodes independently assimilate propagated information to form depth hypotheses which are then tracked and updated on-line as more data is gathered. Consequently, we can extract at any time a "current-best" estimate for all nodes, plus co-located uncertainties and other metrics. The method can assimilate data from multiple surveys, multiple instruments or repeated passes of the same instrument in real-time as data is being gathered. The data assimilation scheme is

  10. Rates and processes of crystallization in on-axis and off-axis MOR basaltic melts

    Science.gov (United States)

    Zellmer, Georg F.; Dulski, Peter; Iizuka, Yoshiyuki; Perfit, Michael R.

    2012-12-01

    Residence times of olivine and plagioclase phenocrysts and xenocrysts in mid-ocean ridge (MOR) basaltic melts have been studied since the mid 1980s using geospeedometric techniques (i.e. using diffusion of major and trace elements) in order to constrain the processes of melt ascent and differentiation in this important magmatic setting. Residence times range from a few hours to several years, but potential links between these timescales and specific tectonomagmatic variables such as spreading rate and relative locations of eruption site and ridge axis have remained elusive. Here we demonstrate how incomplete chemical diffusion of Sr within plagioclase crystals from MOR basalts erupted in on- and off-axis settings on a number of ridges with variable spreading rates provide geospeedometric constraints. We combine electron probe microanalytical crystal maps with detailed laser ablation profiles of almost 70 plagioclase crystals from the fast spreading East Pacific Rise (EPR) at 9-10°N, the intermediate spreading Gorda and Juan de Fuca (JdF) ridges, and the ultraslow spreading Gakkel ridge to calculate crystal residence times. These range from a few days to several months. The scarcity of residence times exceeding years corroborates previous data indicating that most of the growth of plagioclase phenocrysts occurs within the conduit at the onset of and during eruption on the sea floor, and extends this result to the fast-spreading EPR. Further, statistical analysis is employed to show for the first time that residence times are systematically longer at slower spreading rates, in off-axis samples, and samples sourced from laterally distal axial melt lenses. Plagioclase textures and residence time variations appear to be linked to differences in the dynamics of late-stage, pre-eruptive magma storage and ascent in the different tectonomagmatic settings investigated. In the future, geospeedometric work on MOR samples will be required to assess if the effect of spreading

  11. Consideration of demand rate in overall equipment effetiveness (OEE on equipment with constant process time

    Directory of Open Access Journals (Sweden)

    Tay C.C.

    2013-06-01

    research should be conducted to test the possibility and to verify the definition of such performance ratio including Takt time on those processes of which its operating time is possibly to be reduced, especially those are not constant and fixed. This piece of research is temporarily done on the process where its operating time is constant from time to time and there is no ideal cycle time possible.Practical implications: The awareness of the overproduction should be emphasized and raised in the intention of pursuing higher OEE value. As the definition proposed such, the process with constant cycle time could even be defined in different performance ratio from time to time regarding to the customer demands and corresponding production rate. These two variables can be adjusted and balanced to increase the OEE value through optimization of average cycle time. Over this, optimization of average cycle time on equipment with constant operating time can be achieved through the optimization of loading number per each processing.Originality/value: The novelty of the paper is the inclusion of customer demand in obtaining OEE value of any particular equipment. Besides that, the equipment without ideal cycle time, which means those processes carried out in constant cycle time are possibly to be evaluated with performance ratio. As consequence of that, the machine utilization and capability used could be quantified and visualized using the performance ratio data of the OEE proposed.

  12. Influence of the relative deformation rate on tube processing by ultrasonic vibration drawing

    Directory of Open Access Journals (Sweden)

    Susan, M.

    2004-04-01

    Full Text Available After a brief review of the "friction reversion mechanism" during ultrasonic vibration drawing of tubes (UVD, the paper introduces a method to determine the drawing force based on the theorem of total consumed power, in the case of tube processing. The experiments performed on tubes made from 10TiNiCr180 (AISI321 austenitic stainless steel confirm the superiority of UVD technology regarding the diminution of the drawing force, the increase of the plasticity and the improvement of the safety coefficient, tendencies that are enhanced with the decrease of the relative drawing rate. The best results were obtained for the relative drawing rate of 0.12 for which the drawing force decreased with 33 %, plasticity increased with 9 % and safety coefficient with 22 %, as compared to CT.

    Después de un breve resumen del mecanismo de reversión de la fricción al estirado por vibraciones ultrasonoras (EVU, el trabajo propone un método para calcular la fuerza de estirado en base al teorema de la potencia total consumida, en el caso particular de la elaboración de tubos. Los experimentos realizados con tubos de acero inoxidable austenítico 10TiNiCr180 (AISI321 demuestran la superioridad de la tecnología EVU sobre la tecnología clásica (TC, en lo concerniente a la reducción de la fuerza de estirado, el incremento de la plasticidad y la mejora del coeficiente de seguridad, tendencias que se acentúan al diminuirse la velocidad relativa de estirado. Los mejores resultados se han obtenido en el caso de la velocidad relativa de 0,12, para la cual la fuerza de estirado se redujo, aproximadamente, un 33 %; la plasticidad se incrementó en el 9 %; y el coeficiente de seguridad aumentó un 22 % frente a la TC.

  13. Nitrogen removal assessment through nitrification rates and media biofilm accumulation in an IFAS process demonstration study.

    Science.gov (United States)

    Regmi, Pusker; Thomas, Wes; Schafran, Gary; Bott, Charles; Rutherford, Bob; Waltrip, David

    2011-12-15

    An IFAS demonstration study was conducted at the 76,000 m(3)/day (20MGD) James River Wastewater Treatment Plant (JRTP) located in Newport News, Virginia by converting one fully-aerobic conventional aeration basin with dedicated secondary clarification to a 7041 m(3)/day (8404 m(3)/day max month) IFAS train in a modified Ludzack-Ettinger (MLE) configuration. During the study, biomass concentrations on the biofilm carriers were monitored (weekly) as well as nitrogen species concentrations in the IFAS reactor to quantify the nitrogen transformations occurring within the demonstration tank. In a related effort, nitrification kinetics for ammonia and nitrite oxidizing bacteria were monitored on a weekly basis for IFAS media alone, IFAS process mixed liquor without media, and IFAS mixed liquor and media together in an effort to identify the location of nitrification activity (i.e. on the media or in the suspended culture) in the IFAS process. Biomass quantity on the media was generally observed to be inversely related to temperature except during a period when an auxiliary carbon source contaminated with fungi was introduced. Both ammonia oxidizing and nitrite oxidizing bacterial activity were elevated on the carriers compared to the suspended culture (AOB(media): 4.97 mgNOx/gMLSS/hr; AOB(suspended): 1.72 mgNOx/gMLSS/hr; NOB(media): 7.55 mgNOx/gMLSS/hr; NOB(suspended): 0.82 mgNOx/gMLSS/hr) during all periods of the study. In-basin nitrification rates calculated based on nitrogen profiling efforts averaged 0.90 mgNOx/m(2)/day which was in good agreement with the average of 0.89 mgNOx/m(2)/day for IFAS mixed liquor and media from batch testing. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Migration processes and self-rated health among marriage migrants in South Korea.

    Science.gov (United States)

    Chang, Hsin-Chieh; Wallace, Steven P

    2016-01-01

    Research on migrant health mostly examines labor migrants, with some attention paid to the trauma faced by refugees. Marriage migrants represent an understudied vulnerable population in the migration and health literature. Drawing on a Social Determinants of Health (SDH) approach, we use a large Korean national survey and stratified multivariate regressions to examine the link between migration processes and the self-rated health of Korea's three largest ethnic groups of marriage migrants: Korean-Chinese, Vietnamese, and Han Chinese. We find that post-migration socioeconomic status and several social integration factors are associated with the health of marriage migrants of all three groups. Specifically, having more social relationships with Koreans is associated with good health among marriage migrants, while having more social relationships with co-ethnics is associated with worse health. Marriage migrants' perceived social status of their natal and marital families is a better predictor of their health than more objective measures such as their education attainment and that of their Korean husbands. The post-migration social gradients among all ethnic groups demonstrate a dose-response effect of marital family's social standing on marriage migrants' health, independent of their own education and the social standing of their natal families. Lastly, we find some ethnicity-specific predictors such as the association between higher educational level and worse health status among the Vietnamese. This variability by group suggests a more complex set of SDH occurred during the marriage migration processes than a basic SDH framework would predict. Using a new immigrant destination, South Korea, as an example, we conclude that migration and health policies that reduce ethnicity-specific barriers and offer integration programs in early post-migration stages may offer a pathway to good health among marriage migrants.

  15. Monte Carlo dose calculations for high-dose-rate brachytherapy using GPU-accelerated processing.

    Science.gov (United States)

    Tian, Z; Zhang, M; Hrycushko, B; Albuquerque, K; Jiang, S B; Jia, X

    2016-01-01

    Current clinical brachytherapy dose calculations are typically based on the Association of American Physicists in Medicine Task Group report 43 (TG-43) guidelines, which approximate patient geometry as an infinitely large water phantom. This ignores patient and applicator geometries and heterogeneities, causing dosimetric errors. Although Monte Carlo (MC) dose calculation is commonly recognized as the most accurate method, its associated long computational time is a major bottleneck for routine clinical applications. This article presents our recent developments of a fast MC dose calculation package for high-dose-rate (HDR) brachytherapy, gBMC, built on a graphics processing unit (GPU) platform. gBMC-simulated photon transport in voxelized geometry with physics in (192)Ir HDR brachytherapy energy range considered. A phase-space file was used as a source model. GPU-based parallel computation was used to simultaneously transport multiple photons, one on a GPU thread. We validated gBMC by comparing the dose calculation results in water with that computed TG-43. We also studied heterogeneous phantom cases and a patient case and compared gBMC results with Acuros BV results. Radial dose function in water calculated by gBMC showed GPU-based MC dose calculation package, gBMC, for HDR brachytherapy make it attractive for clinical applications. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  16. On dual nature of effect of adsorbed polymeric hydroxide films on rate of different electrode processes

    International Nuclear Information System (INIS)

    Zakharkina, P.S.; Korshunov, V.N.

    1985-01-01

    The effect of cation Er 3+ hydrolysis products on the electrochemical behaviour of Zn and Na amalgams is studied. The i, t-curves are presented which are moasUred from a film Hg-electrode in 1M LiCl- and 1MNaCl solUtions both with and without the 10 -3 MErCl 3 addition, along with the I, t-dependences obtained from a rotation disk Zn-electrode at E=-1.45 B against the background of 0.1 MLi 2 SO 4 with the 1.5x10 -3 M Er 2 (SO 4 ) 3 addition. Polymeric films of REE oxohydroxo compounds exhibit a distinct dualism in the effect on the rate of different electrode reactions; provided a proton donor is the depolarizator, the films being considered confirm their name of catalytically active matrices accelerating hydrogen evolution by a modified bridge mechanism variant. In case of metal charge-ionization process these films become inhibitors and the more effective, the more hydrated is the corresponding REE ion

  17. Task Balanced Workflow Scheduling Technique considering Task Processing Rate in Spot Market

    Directory of Open Access Journals (Sweden)

    Daeyong Jung

    2014-01-01

    Full Text Available Recently, the cloud computing is a computing paradigm that constitutes an advanced computing environment that evolved from the distributed computing. And the cloud computing provides acquired computing resources in a pay-as-you-go manner. For example, Amazon EC2 offers the Infrastructure-as-a-Service (IaaS instances in three different ways with different price, reliability, and various performances of instances. Our study is based on the environment using spot instances. Spot instances can significantly decrease costs compared to reserved and on-demand instances. However, spot instances give a more unreliable environment than other instances. In this paper, we propose the workflow scheduling scheme that reduces the out-of-bid situation. Consequently, the total task completion time is decreased. The simulation results reveal that, compared to various instance types, our scheme achieves performance improvements in terms of an average combined metric of 12.76% over workflow scheme without considering the processing rate. However, the cost in our scheme is higher than an instance with low performance and is lower than an instance with high performance.

  18. Earth-based radar and LRO Diviner constraints on the recent rate of lunar ejecta processing

    Science.gov (United States)

    Ghent, Rebecca R.; Hayne, Paul O.; Bandfield, Joshua L.; Campbell, Bruce A.; Carter, Lynn M.; Allen, Carlton

    2013-04-01

    Many large craters on the lunar nearside show radar circular polarization ratio (CPR) signatures consistent with the presence of blocky ejecta blankets, to distances of 0.5 to 1.5 crater radii. However, most of these surfaces show very low surface rock concentration values and only limited enhancements in regolith temperatures calculated from Diviner nighttime infrared observations. Because the radar signal is integrated over the radar penetration depth (up to several meters), but the Diviner signal is sensitive only to rocks within the upper meter of the surface, this indicates that ejecta blocks on the surface and in the shallow subsurface are quickly removed by continued bombardment. Deeper subsurface rocks, which are clearly evident in radar CPR maps but are covered by a sufficiently thick layer of thermally insulating regolith material to render them invisible to Diviner, persist for much longer. By matching the results of one-dimensional thermal models to Diviner nighttime temperatures, we can constrain the thermophysical properties of the upper 1 meter of regolith. We find that Diviner nighttime cooling curves are best fit by a density profile that varies exponentially with depth, consistent with a mixture of rocks and regolith fines, with increasing rock content with depth. Using this density profile together with the surface rock abundance, we can estimate the excess rock mass represented by rocks on the surface and within the upper meter of regolith for individual craters. We find that for craters of known age younger than ~1.7Ga, a robust correlation exists between ejecta mass and crater age, which yields the first observational estimate of the rate of lunar ejecta processing. Our results show that crater ejecta are initially removed very quickly (perhaps up to ~1cm / m.y.), with the rate slowing over a short period of time to less than 1 mm / m.y., as the number of blocks on the surface decreases and the volume of protective regolith material increases

  19. The Effect of Shear Rate on Dissolution of Gas and Cell Density in Continuous Foaming Process

    Directory of Open Access Journals (Sweden)

    M.H.N. Famili

    2009-12-01

    Full Text Available The effect of shear rate on dissolution of carbon dioxide in viscoelastic wheat flour matrix and cell density in a glass barrel twin screw extruder is investigated. It is found that by increasing the shear rate there will be a decrease in the required thermodynamic conditions and hence, it improves blowing agent dissolution and increases the cell density. Shear rate breaks up big bubbles and helps to better distribute the blowing agent in the matrix and hence it increases the cell density. Cell density decreases by dropping foam cooling rate. For a given cell density, a higher screw speed is needed, ifthe cooling rate is decreased.

  20. Learning to maximize reward rate: a model based on semi-Markov decision processes.

    Science.gov (United States)

    Khodadadi, Arash; Fakhari, Pegah; Busemeyer, Jerome R

    2014-01-01

    WHEN ANIMALS HAVE TO MAKE A NUMBER OF DECISIONS DURING A LIMITED TIME INTERVAL, THEY FACE A FUNDAMENTAL PROBLEM: how much time they should spend on each decision in order to achieve the maximum possible total outcome. Deliberating more on one decision usually leads to more outcome but less time will remain for other decisions. In the framework of sequential sampling models, the question is how animals learn to set their decision threshold such that the total expected outcome achieved during a limited time is maximized. The aim of this paper is to provide a theoretical framework for answering this question. To this end, we consider an experimental design in which each trial can come from one of the several possible "conditions." A condition specifies the difficulty of the trial, the reward, the penalty and so on. We show that to maximize the expected reward during a limited time, the subject should set a separate value of decision threshold for each condition. We propose a model of learning the optimal value of decision thresholds based on the theory of semi-Markov decision processes (SMDP). In our model, the experimental environment is modeled as an SMDP with each "condition" being a "state" and the value of decision thresholds being the "actions" taken in those states. The problem of finding the optimal decision thresholds then is cast as the stochastic optimal control problem of taking actions in each state in the corresponding SMDP such that the average reward rate is maximized. Our model utilizes a biologically plausible learning algorithm to solve this problem. The simulation results show that at the beginning of learning the model choses high values of decision threshold which lead to sub-optimal performance. With experience, however, the model learns to lower the value of decision thresholds till finally it finds the optimal values.

  1. The effect of Process Parameters on Material Removal Rate in Drilling of Al 6061-SiC composite

    Directory of Open Access Journals (Sweden)

    Deepak D.

    2018-01-01

    Full Text Available This study investigates the effect of process parameters such as diameter of drill, cutting velocity, feed rate and coolant supply on material removal rate while drilling of Al-SiC composite. Sample specimens are prepared by stir-casting method and experiments are designed using Taguchi’s L9 orthogonal array. Response data is analysed using S/N ratio and significant process parameters are identified using Analysis of Variance (ANOVA. Study shows that drill diameter, followed by feed rate are found to be the most significant factors which influence MRR.

  2. Economic analysis of solar industrial process heat systems: A methodology to determine annual required revenue and internal rate of return

    Science.gov (United States)

    Dickinson, W. C.; Brown, K. C.

    1981-08-01

    An economic evaluation of solar industrial process heat systems, is developed to determine the annual required revenue and the internal rate of return. First, a format is provided to estimate the solar system's installed cost, annual operating and maintenance expenses, and net annual solar energy delivered to the industrial process. The annual required revenue and the price of solar is calculated. The economic attractiveness of the potential solar investment can be determined by comparing the price of solar energy with the price of fossilfuel, both expressed in levelized terms. This requires calcuation of the internal rate of return on the solar investment or, in certain cases, the growth rate of return.

  3. The Effect of Shear Rate on Dissolution of Gas and Cell Density in Continuous Foaming Process

    OpenAIRE

    M.H.N. Famili; M. Ako

    2009-01-01

    The effect of shear rate on dissolution of carbon dioxide in viscoelastic wheat flour matrix and cell density in a glass barrel twin screw extruder is investigated. It is found that by increasing the shear rate there will be a decrease in the required thermodynamic conditions and hence, it improves blowing agent dissolution and increases the cell density. Shear rate breaks up big bubbles and helps to better distribute the blowing agent in the matrix and hence it increases the cell density. Ce...

  4. Evaluation of Chemical Kinetic for Mathematics Model Reduction of Cadmium Reaction Rate, Constant and Reaction Orde in to Electrochemical Process

    International Nuclear Information System (INIS)

    Prayitno

    2007-01-01

    The experiment was reduction of cadmium rate with electrochemical influenced by time process, concentration, current strength and type of electrode plate. The aim of the experiment was to know the influence, mathematic model reduction of cadmium the reaction rate, reaction rate constant and reaction orde influenced by time process, concentration, current strength and type of electrode plate. Result of research indicate the time processing if using plate of copper electrode is during 30 minutes and using plate of aluminium electrode is during 20 minutes. Condition of strong current that used in process of electrochemical is only 0.8 ampere and concentration effective is 5.23 mg/l. The most effective type Al of electrode plate for reduction from waste and the efficiency of reduction is 98 %. (author)

  5. Heuristic Processes in Ratings of Leader Behavior: Assessing Item-Induced Availability Biases.

    Science.gov (United States)

    Binning, John F.; Fernandez, Guadalupe

    Since observers' memory-based ratings of organizational phenomena provide data in research and decision-making contexts, bias in observers' judgments must be examined. A study was conducted to explore the extent to which leader behavior ratings are more generally biased by the availability heuristic. The availability heuristic is operative when a…

  6. Can Two Psychotherapy Process Measures Be Dependably Rated Simultaneously? A Generalizability Study

    Science.gov (United States)

    Ulvenes, Pal G.; Berggraf, Lene; Hoffart, Asle; Levy, Raymon A.; Ablon, J. Stuart; McCullough, Leigh; Wampold, Bruce E.

    2012-01-01

    Observer ratings in psychotherapy are a common way of collecting information in psychotherapy research. However, human observers are imperfect instruments, and their ratings may be subject to variability from several sources. One source of variability can be raters' assessing more than 1 instrument at a time. The purpose of this research is to…

  7. Generalized Temporal Acceleration Scheme for Kinetic Monte Carlo Simulations of Surface Catalytic Processes by Scaling the Rates of Fast Reactions.

    Science.gov (United States)

    Dybeck, Eric C; Plaisance, Craig P; Neurock, Matthew

    2017-04-11

    A novel algorithm is presented that achieves temporal acceleration during kinetic Monte Carlo (KMC) simulations of surface catalytic processes. This algorithm allows for the direct simulation of reaction networks containing kinetic processes occurring on vastly disparate time scales which computationally overburden standard KMC methods. Previously developed methods for temporal acceleration in KMC were designed for specific systems and often require a priori information from the user such as identifying the fast and slow processes. In the approach presented herein, quasi-equilibrated processes are identified automatically based on previous executions of the forward and reverse reactions. Temporal acceleration is achieved by automatically scaling the intrinsic rate constants of the quasi-equilibrated processes, bringing their rates closer to the time scales of the slow kinetically relevant nonequilibrated processes. All reactions are still simulated directly, although with modified rate constants. Abrupt changes in the underlying dynamics of the reaction network are identified during the simulation, and the reaction rate constants are rescaled accordingly. The algorithm was utilized here to model the Fischer-Tropsch synthesis reaction over ruthenium nanoparticles. This reaction network has multiple time-scale-disparate processes which would be intractable to simulate without the aid of temporal acceleration. The accelerated simulations are found to give reaction rates and selectivities indistinguishable from those calculated by an equivalent mean-field kinetic model. The computational savings of the algorithm can span many orders of magnitude in realistic systems, and the computational cost is not limited by the magnitude of the time scale disparity in the system processes. Furthermore, the algorithm has been designed in a generic fashion and can easily be applied to other surface catalytic processes of interest.

  8. Steam distillation extraction of ginger essential oil: Study of the effect of steam flow rate and time process

    Science.gov (United States)

    Fitriady, Muhammad Arifuddin; Sulaswatty, Anny; Agustian, Egi; Salahuddin, Aditama, Deska Prayoga Fauzi

    2017-01-01

    In Indonesia ginger was usually used as a seasoning for dishes, an ingredient for beverage and a source of herbal medicines. Beside raw usage, ginger can be processed to obtain the essential oil which has many advantages such as proven to be an active antimicrobial and having an antioxidant ability. There are a lot of methods to extract essential oil from ginger, one of which is steam distillation. The aim of the current study was to investigate the effect of variation of time process and steam flow rate in the yield on ginger essential oil steam distillation extraction process. It was found that the best operation condition was 0.35 ml/s as the steam flow rate which yields 2.43% oil. The optimum time process was predicted at 7.5 hours. The composition of the oil was varied depend on the flow rate and every flow rate has its own major component contained in the oil. Curcumene composition in the oil was increased as increased steam flow rate applied, but the composition of camphene was decreased along with the increasing steam flow rate.

  9. Don't speak too fast! Processing of fast rate speech in children with specific language impairment.

    Directory of Open Access Journals (Sweden)

    Hélène Guiraud

    Full Text Available Perception of speech rhythm requires the auditory system to track temporal envelope fluctuations, which carry syllabic and stress information. Reduced sensitivity to rhythmic acoustic cues has been evidenced in children with Specific Language Impairment (SLI, impeding syllabic parsing and speech decoding. Our study investigated whether these children experience specific difficulties processing fast rate speech as compared with typically developing (TD children.Sixteen French children with SLI (8-13 years old with mainly expressive phonological disorders and with preserved comprehension and 16 age-matched TD children performed a judgment task on sentences produced 1 at normal rate, 2 at fast rate or 3 time-compressed. Sensitivity index (d' to semantically incongruent sentence-final words was measured.Overall children with SLI perform significantly worse than TD children. Importantly, as revealed by the significant Group × Speech Rate interaction, children with SLI find it more challenging than TD children to process both naturally or artificially accelerated speech. The two groups do not significantly differ in normal rate speech processing.In agreement with rhythm-processing deficits in atypical language development, our results suggest that children with SLI face difficulties adjusting to rapid speech rate. These findings are interpreted in light of temporal sampling and prosodic phrasing frameworks and of oscillatory mechanisms underlying speech perception.

  10. Don't speak too fast! Processing of fast rate speech in children with specific language impairment.

    Science.gov (United States)

    Guiraud, Hélène; Bedoin, Nathalie; Krifi-Papoz, Sonia; Herbillon, Vania; Caillot-Bascoul, Aurélia; Gonzalez-Monge, Sibylle; Boulenger, Véronique

    2018-01-01

    Perception of speech rhythm requires the auditory system to track temporal envelope fluctuations, which carry syllabic and stress information. Reduced sensitivity to rhythmic acoustic cues has been evidenced in children with Specific Language Impairment (SLI), impeding syllabic parsing and speech decoding. Our study investigated whether these children experience specific difficulties processing fast rate speech as compared with typically developing (TD) children. Sixteen French children with SLI (8-13 years old) with mainly expressive phonological disorders and with preserved comprehension and 16 age-matched TD children performed a judgment task on sentences produced 1) at normal rate, 2) at fast rate or 3) time-compressed. Sensitivity index (d') to semantically incongruent sentence-final words was measured. Overall children with SLI perform significantly worse than TD children. Importantly, as revealed by the significant Group × Speech Rate interaction, children with SLI find it more challenging than TD children to process both naturally or artificially accelerated speech. The two groups do not significantly differ in normal rate speech processing. In agreement with rhythm-processing deficits in atypical language development, our results suggest that children with SLI face difficulties adjusting to rapid speech rate. These findings are interpreted in light of temporal sampling and prosodic phrasing frameworks and of oscillatory mechanisms underlying speech perception.

  11. Nonequilibrium thermodynamics transport and rate processes in physical, chemical and biological systems

    CERN Document Server

    Demirel, Yasar

    2014-01-01

    Natural phenomena consist of simultaneously occurring transport processes and chemical reactions. These processes may interact with each other and may lead to self-organized structures, fluctuations, instabilities, and evolutionary systems. Nonequilibrium Thermodynamics, 3rd edition emphasizes the unifying role of thermodynamics in analyzing the natural phenomena. This third edition updates and expands on the first and second editions by focusing on the general balance equations for coupled processes of physical, chemical, and biological systems. The new edition contains a new chapte

  12. (n,{gamma}) and (p,{gamma}) rates for s- and p-process nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kaeppeler, F. [Forschungszentrum Karlsruhe, Karlsruhe (Germany)

    1998-06-01

    The late stages of stellar evolution are characterized by a series of nucleosynthesis events. With respect to the heavy elements, these are the s process associated with the helium burning layers in Red Giant stars as well as the r and p processes which occur in supernova explosions. In contrast to the explosive scenarios, the nuclear physics data for s-process studies can be determined in laboratory experiments as illustrated at few recent examples. The application of these techniques to measurements of relevance for the p process are also discussed. (orig.)

  13. Sustainable agro-food industrial wastewater treatment using high rate anaerobic process

    OpenAIRE

    Rajagopal, Rajinikanth; Saady, Noori M. Cata; Torrijos, Michel; Thanikal, Joseph V.; Hung, Yung-Tse

    2013-01-01

    This review article compiles the various advances made since 2008 in sustainable high-rate anaerobic technologies with emphasis on their performance enhancement when treating agro-food industrial wastewater. The review explores the generation and characteristics of different agro-food industrial wastewaters; the need for and the performance of high rate anaerobic reactors, such as an upflow anaerobic fixed bed reactor, an upflow anaerobic sludge blanket (UASB) reactor, hybrid systems etc.; op...

  14. A comprehensive mathematical model for estimating oil drainage rate in SAGD process considering wellbore/formation coupling effect

    Science.gov (United States)

    Cheng, Linsong; Gu, Hao; Huang, Shijun

    2017-05-01

    The aim of this work is to present a comprehensive mathematical model for estimating oil drainage rate in Steam-assisted gravity drainage (SAGD) process, more importantly, wellbore/formation coupling effect is considered. Firstly, mass and heat transfer in vertical and horizontal wellbores are described briefly. Then, a function of steam chamber height is introduced and the expressions for oil drainage rate in rising and expanding steam chamber stages are derived in detail. Next, a calculation flowchart is provided and an example is given to introduce how to use the proposed method. Finally, after the mathematical model is validated, the effects of wellhead steam injection rate on simulated results are further analyzed. The results indicate that heat injection power per meter reduces gradually along the horizontal wellbore, which affects both steam chamber height and oil drainage rate in the SAGD process. In addition, when production time is the same, the calculated oil drainage rate from the new method is lower than that from Butler's method. Moreover, the paper shows that when wellhead steam injection rate is low enough, the steam chamber is not formed at the horizontal well's toe position and enhancing the wellhead steam injection rate can increase the oil drainage rate.

  15. Dry fermentation of manure with straw in continuous plug flow reactor: Reactor development and process stability at different loading rates.

    Science.gov (United States)

    Patinvoh, Regina J; Kalantar Mehrjerdi, Adib; Sárvári Horváth, Ilona; Taherzadeh, Mohammad J

    2017-01-01

    In this work, a plug flow reactor was developed for continuous dry digestion processes and its efficiency was investigated using untreated manure bedded with straw at 22% total solids content. This newly developed reactor worked successfully for 230days at increasing organic loading rates of 2.8, 4.2 and 6gVS/L/d and retention times of 60, 40 and 28days, respectively. Organic loading rates up to 4.2gVS/L/d gave a better process stability, with methane yields up to 0.163LCH 4 /gVS added /d which is 56% of the theoretical yield. Further increase of organic loading rate to 6gVS/L/d caused process instability with lower volatile solid removal efficiency and cellulose degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Hazard rate model and statistical analysis of a compound point process

    Czech Academy of Sciences Publication Activity Database

    Volf, Petr

    2005-01-01

    Roč. 41, č. 6 (2005), s. 773-786 ISSN 0023-5954 R&D Projects: GA ČR(CZ) GA402/04/1294 Institutional research plan: CEZ:AV0Z10750506 Keywords : couting process * compound process * Cox regression model * intensity Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.343, year: 2005

  17. Unbounded-rate Markov decision processes : structural properties via a parametrisation approach

    NARCIS (Netherlands)

    Blok, H.

    2016-01-01

    This research is interested in optimal control of Markov decision processes (MDPs). Herein a key role is played by structural properties. Properties such as monotonicity and convexity help in finding the optimal policy. Value iteration is a tool to derive such properties in discrete time processes.

  18. Can rasch analysis enhance the abstract ranking process in scientific conferences? Issues of interrater variability and abstract rating burden.

    Science.gov (United States)

    Scanlan, Justin Newton; Lannin, Natasha A; Hoffmann, Tammy

    2015-01-01

    Abstract ranking processes for scientific conferences are essential but controversial. This study examined the validity of a structured abstract rating instrument, evaluated interrater variability, and modeled the impact of interrater variability on abstract ranking decisions. Additionally, we examined whether a more efficient rating process (abstracts rated by two rather than three raters) supported valid abstract rankings. Data were 4016 sets of abstract ratings from the 2011 and 2013 national scientific conferences for a health discipline. Many-faceted Rasch analysis procedures were used to examine validity of the abstract rating instrument and to identify and adjust for the presence of interrater variability. The two-rater simulation was created by the deletion of one set of ratings for each abstract in the 2013 data set. The abstract rating instrument demonstrated sound measurement properties. Although each rater applied the rating criteria consistently (intrarater reliability), there was significant variability between raters. Adjusting for interrater variability changed the final presentation format for approximately 10-20% of abstracts. The two-rater simulation demonstrated that abstract rankings derived through this process were valid, although the impact of interrater variability was more substantial. Interrater variability exerts a small but important influence on overall abstract acceptance outcome. The use of many-faceted Rasch analysis allows for this variability to be adjusted for. Additionally, Rasch processes allow for more efficient abstract ranking by reducing the need for multiple raters. © 2015 The Alliance for Continuing Education in the Health Professions, the Society for Academic Continuing Medical Education, and the Council on Continuing Medical Education, Association for Hospital Medical Education.

  19. Acetylene Flow Rate as a Crucial Parameter of Vacuum Carburizing Process of Modern Tool Steels

    Directory of Open Access Journals (Sweden)

    Rokicki P.

    2016-12-01

    Full Text Available Carburizing is one of the most popular and wide used thermo-chemical treatment methods of surface modification of tool steels. It is a process based on carbon diffusive enrichment of the surface material and is applied for elements that are supposed to present higher hardness and wear resistance sustaining core ductility. Typical elements submitted to carburizing process are gears, shafts, pins and bearing elements. In the last years, more and more popular, especially in highly advanced treatment procedures used in the aerospace industry is vacuum carburizing. It is a process based on chemical treatment of the surface in lower pressure, providing much higher uniformity of carburized layer, lower process cost and much lesser negative impact on environment to compare with conventional carburizing methods, as for example gas carburizing in Endo atmosphere. Unfortunately, aerospace industry requires much more detailed description of the phenomena linked to this process method and the literature background shows lack of tests that could confirm fulfilment of all needed requirements and to understand the process itself in much deeper meaning. In the presented paper, authors focused their research on acetylene flow impact on carburized layer characteristic. This is one of the most crucial parameters concerning homogeneity and uniformity of carburized layer properties. That is why, specific process methodology have been planned based on different acetylene flow values, and the surface layer of the steel gears have been investigated in meaning to impact on any possible change in potential properties of the final product.

  20. Shell-model calculations of beta-decay rates for s- and r-process nucleosyntheses

    International Nuclear Information System (INIS)

    Takahashi, K.; Mathews, G.J.; Bloom, S.D.

    1985-01-01

    Examples of large-basis shell-model calculations of Gamow-Teller β-decay properties of specific interest in the astrophysical s- and r- processes are presented. Numerical results are given for: (1) the GT-matrix elements for the excited state decays of the unstable s-process nucleus 99 Tc; and (2) the GT-strength function for the neutron-rich nucleus 130 Cd, which lies on the r-process path. The results are discussed in conjunction with the astrophysics problems. 23 refs., 3 figs

  1. Reducing Error Rates for Iris Image using higher Contrast in Normalization process

    Science.gov (United States)

    Aminu Ghali, Abdulrahman; Jamel, Sapiee; Abubakar Pindar, Zahraddeen; Hasssan Disina, Abdulkadir; Mat Daris, Mustafa

    2017-08-01

    Iris recognition system is the most secured, and faster means of identification and authentication. However, iris recognition system suffers a setback from blurring, low contrast and illumination due to low quality image which compromises the accuracy of the system. The acceptance or rejection rates of verified user depend solely on the quality of the image. In many cases, iris recognition system with low image contrast could falsely accept or reject user. Therefore this paper adopts Histogram Equalization Technique to address the problem of False Rejection Rate (FRR) and False Acceptance Rate (FAR) by enhancing the contrast of the iris image. A histogram equalization technique enhances the image quality and neutralizes the low contrast of the image at normalization stage. The experimental result shows that Histogram Equalization Technique has reduced FRR and FAR compared to the existing techniques.

  2. Sustainable Agro-Food Industrial Wastewater Treatment Using High Rate Anaerobic Process

    Directory of Open Access Journals (Sweden)

    Yung-Tse Hung

    2013-03-01

    Full Text Available This review article compiles the various advances made since 2008 in sustainable high-rate anaerobic technologies with emphasis on their performance enhancement when treating agro-food industrial wastewater. The review explores the generation and characteristics of different agro-food industrial wastewaters; the need for and the performance of high rate anaerobic reactors, such as an upflow anaerobic fixed bed reactor, an upflow anaerobic sludge blanket (UASB reactor, hybrid systems etc.; operational challenges, mass transfer considerations, energy production estimation, toxicity, modeling, technology assessment and recommendations for successful operation

  3. Bioreactor scale-up and oxygen transfer rate in microbial processes: an overview.

    Science.gov (United States)

    Garcia-Ochoa, Felix; Gomez, Emilio

    2009-01-01

    In aerobic bioprocesses, oxygen is a key substrate; due to its low solubility in broths (aqueous solutions), a continuous supply is needed. The oxygen transfer rate (OTR) must be known, and if possible predicted to achieve an optimum design operation and scale-up of bioreactors. Many studies have been conducted to enhance the efficiency of oxygen transfer. The dissolved oxygen concentration in a suspension of aerobic microorganisms depends on the rate of oxygen transfer from the gas phase to the liquid, on the rate at which oxygen is transported into the cells (where it is consumed), and on the oxygen uptake rate (OUR) by the microorganism for growth, maintenance and production. The gas-liquid mass transfer in a bioprocess is strongly influenced by the hydrodynamic conditions in the bioreactors. These conditions are known to be a function of energy dissipation that depends on the operational conditions, the physicochemical properties of the culture, the geometrical parameters of the bioreactor and also on the presence of oxygen consuming cells. Stirred tank and bubble column (of various types) bioreactors are widely used in a large variety of bioprocesses (such as aerobic fermentation and biological wastewater treatments, among others). Stirred tanks bioreactors provide high values of mass and heat transfer rates and excellent mixing. In these systems, a high number of variables affect the mass transfer and mixing, but the most important among them are stirrer speed, type and number of stirrers and gas flow rate used. In bubble columns and airlifts, the low-shear environment compared to the stirred tanks has enabled successful cultivation of shear sensitive and filamentous cells. Oxygen transfer is often the rate-limiting step in the aerobic bioprocess due to the low solubility of oxygen in the medium. The correct measurement and/or prediction of the volumetric mass transfer coefficient, (k(L)a), is a crucial step in the design, operation and scale-up of

  4. Collaborative Project: Understanding the Chemical Processes tat Affect Growth rates of Freshly Nucleated Particles

    Energy Technology Data Exchange (ETDEWEB)

    McMurry, Peter [Univ. of Minnesota, Minneapolis, MN (United States); Smuth, James [University Corporation for Atmospheric Research, Irvine, CA (United States)

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate.

  5. Effect of process parameters on growth rate and diameter of nano ...

    Indian Academy of Sciences (India)

    pores with high aspect ratio was fabricated by two-step anodization processes from high purity aluminium foil. It was observed that pore dimen- sions were affected by anodizing voltage, electrolyte temperature and the duration of anodization ...

  6. The rate limiting process and its activation energy in the forming process of a Cu/Ta2O5/Pt gapless-type atomic switch

    Science.gov (United States)

    Shigeoka, Yuki; Tsuruoka, Tohru; Hasegawa, Tsuyoshi

    2018-03-01

    The rate limiting process in first resistive switching, called the “forming process”, is determined by measuring the switching time of an as-fabricated Cu/Ta2O5/Pt atomic switch as a function of the ambient temperature and the Ta2O5 thickness. The temperature dependence is well fitted by the Arrhenius equation, suggesting that a certain activation process dominates the switching phenomenon. The switching time increases linearly as the Ta2O5 thickness increases. The results herein clearly suggest that the rate limiting process is the drift of Cu cations in the Ta2O5 layer. We determine that the activation energy is 0.4 eV.

  7. Morphological characteristics of polyvinyl chloride (PVC) dechlorination during pyrolysis process: Influence of PVC content and heating rate.

    Science.gov (United States)

    Cao, Qiongmin; Yuan, Guoan; Yin, Lijie; Chen, Dezhen; He, Pinjing; Wang, Hai

    2016-12-01

    In this research morphological techniques were used to characterize dechlorination process of PVC when it is in the mixed waste plastics and the two important factors influencing this process, namely, the proportion of PVC in the mixed plastics and heating rate adopted in the pyrolysis process were investigated. During the pyrolysis process for the mixed plastics containing PVC, the morphologic characteristics describing PVC dechlorination behaviors were obtained with help of a high-speed infrared camera and image processing tools. At the same time emission of hydrogen chloride (HCl) was detected to find out the start and termination of HCl release. The PVC contents in the mixed plastics varied from 0% to 12% in mass and the heating rate for PVC was changed from 10 to 60°C/min. The morphologic parameters including "bubble ratio" (BR) and "pixel area" (PA) were found to have obvious features matching with PVC dechlorination process therefore can be used to characterize dechlorination of PVC alone and in the mixed plastics. It has been also found that shape of HCl emission curve is independent of PVC proportions in the mixed plastics, but shifts to right side with elevated heating rate; and all of which can be quantitatively reflected in morphologic parameters vs. temperature curves. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The Perceived Impact of Teacher Performance Ratings on the Teacher Evaluation Process: Voices from the Field

    Science.gov (United States)

    Bullis, Brian

    2014-01-01

    The purpose of this study was focused on the various perceived impacts created by the expansion to a four-tier teacher performance evaluation rating model which would inform educational leaders in the State of Illinois. By studying the experiences of principals in two other states who previously underwent the same change, Florida and…

  9. Simulating species loss following perturbation: assessing the effects on process rates.

    Science.gov (United States)

    Jonsson, Micael; Dangles, Olivier; Malmqvist, Björn; Guérold, Francois

    2002-01-01

    We removed stream-living macroinvertebrate shredder species in the sequences in which they are predicted to disappear, in response to two common types of anthropogenic disturbances: acidification and organic pollution, and analysed the effects on leaf breakdown rates. The experiment was performed in field microcosms using three shredder species. Species identity significantly affected leaf breakdown rates, while species richness per se was non-significant. The simulated sequential species loss showed large effects on leaf breakdown rates, with observed rates being significantly higher than expected from single-species treatments in two, out of four, two-species, and in all four three-species treatments. The invertebrates used in this study were taxonomically distinct (Insecta: Plecoptera and Trichoptera; Crustacea: Amphipoda), and of different sizes, hence a high degree of complementarity was probably present. A method to study the effects of species loss, characteristic of perturbation type, could be more useful than a random approach when investigating the impact of perturbation. Our results may have general applicability for investigations on the effects of diversity loss on ecosystem functioning in any ecosystem exposed to human perturbations, given that the order of extinction is known or can easily be assessed. PMID:12028762

  10. Attentional Processing and Teacher Ratings in Hyperactive, Learning Disabled and Normal Boys.

    Science.gov (United States)

    Brown, Ronald T.; Wynne, Martha Ellen

    Sustained attention and inhibitory control of 15 nonhyperactive, learning disabled (LD) boys, 15 hyperactive but not LD boys, and 15 normal boys (11-12 years old) were studied, on teacher ratings of impulse control in the classroom and testing results. Coming to attention, decision making, sustained attention, and attention-concentration were…

  11. Effect of ammonia on methane production pathways and reaction rates in acetate-fed biogas processes.

    Science.gov (United States)

    Hao, L P; Mazéas, L; Lü, F; Grossin-Debattista, J; He, P J; Bouchez, T

    2017-04-01

    In order to understand the correlation between ammonia and methanogenesis metabolism, methane production pathways and their specific rates were studied at total ammonium nitrogen (TAN) concentrations of 0.14-9 g/L in three methanogenic sludges fed with acetate, at both mesophilic and thermophilic conditions. Results showed that high levels of TAN had significant inhibition on methanogenesis; this could, however, be recovered via syntrophic acetate oxidation (SAO) coupled with Hydrogenotrophic Methanogenesis (HM) performed by acetate oxidizing syntrophs or through Acetoclastic Methanogenesis (AM) catalyzed by Methanosarcinaceae, after a long lag phase >50 d. Free ammonia (NH 3 ) was the active component for this inhibition, of which 200 mg/L is suggested as the threshold for the pathway shift from AM to SAO-HM. Methane production rate via SAO-HM at TAN of 7-9 g/L was about 5-9-fold lower than that of AM at TAN of 0.14 g/L, which was also lower than the rate of AM pathway recovered at TAN of 7 g/L in the incubations with a French mesophilic inoculum. Thermophilic condition favored the establishment of the SAO-catalyzing microbial community, as indicated by the higher reaction rate and shorter lag phase. The operational strategy is thus suggested to be adjusted when NH 3 exceeds 200 mg/L.

  12. Simultaneous time-resolved measurement of the reaction rates and the refractive index of photopolymerization processes

    NARCIS (Netherlands)

    Bak, Tomasz M; Beusink, J Bianca; Subramaniam, Vinod; Kanger, Johannes S

    2010-01-01

    We explore the use of imaging surface plasmon resonance (iSPR) to simultaneously measure the refractive index and reaction rates of the commercially available Ormocore photosensitive resist during photopolymerization. To this end, we adapted a commercially available iSPR device. We demonstrate good

  13. 49 CFR Appendix B to Part 385 - Explanation of Safety Rating Process

    Science.gov (United States)

    2010-10-01

    ... commerce or within Canada or Mexico (if the motor carrier also operates in the United States) that results..., including if applicable its operations in Canada and/or Mexico. I. Source of Data for Rating Methodology (a... motor vehicles operating in interstate or foreign commerce. The Secretary, in turn, delegated this...

  14. Seasonal variations in ectotherm growth rates: Quantifying growth as an intermittent non steady state compensatory process

    Science.gov (United States)

    Guarini, J.-M.; Chauvaud, Laurent; Cloern, J.E.; Clavier, J.; Coston-Guarini, J.; Patry, Y.

    2011-01-01

    Generally, growth rates of living organisms are considered to be at steady state, varying only under environmental forcing factors. For example, these rates may be described as a function of light for plants or organic food resources for animals and these could be regulated (or not) by temperature or other conditions. But, what are the consequences for an individual's growth (and also for the population growth) if growth rate variations are themselves dynamic and not steady state? For organisms presenting phases of dormancy or long periods of stress, this is a crucial question. A dynamic perspective for quantifying short-term growth was explored using the daily growth record of the scallop Pecten maximus (L.). This species is a good biological model for ectotherm growth because the shell records growth striae daily. Independently, a generic mathematical function representing the dynamics of mean daily growth rate (MDGR) was implemented to simulate a diverse set of growth patterns. Once the function was calibrated with the striae patterns, the growth rate dynamics appeared as a forced damped oscillation during the growth period having a basic periodicity during two transitory phases (mean duration 43. days) and appearing at both growth start and growth end. This phase is most likely due to the internal dynamics of energy transfer within the organism rather than to external forcing factors. After growth restart, the transitory regime represents successive phases of over-growth and regulation. This pattern corresponds to a typical representation of compensatory growth, which from an evolutionary perspective can be interpreted as an adaptive strategy to coping with a fluctuating environment. ?? 2011 Elsevier B.V.

  15. Aggregate size and architecture determine biomass activity for one-stage partial nitritation and anammox

    DEFF Research Database (Denmark)

    Vlaeminck, S.; Terada, Akihiko; Smets, Barth F.

    2010-01-01

    to the inoculation and operation of the reactors. Fluorescent in-situ hybridization (FISH) was applied on aggregate sections to quantify AerAOB and AnAOB, as well as to visualize the aggregate architecture. The activity balance of the aggregates was calculated as the nitrite accumulation rate ratio (NARR), i.......e. the net aerobic nitrite production rate divided by the anoxic nitrite consumption rate, with all rates determined in aerobic and anoxic batch tests. The space occupied by extracellular polymeric substances (EPS) was calculated from transmission electron micrographs. All smallest aggregates were flocs...... and nitrite sources (NARR, > 1.7). Large A and C aggregates were granules capable of autonomous nitrogen removal (NARR, 0.6 to 1.1) with internal AnAOB zones surrounded by an AerAOB rim. Around 50% of the autotrophic space in these granules consisted of AerAOB- and AnAOB-specific EPS. Large B aggregates were...

  16. Reduction in Repair rate of Welding Processes by Determination & Controlling of Critical KPIVs

    Directory of Open Access Journals (Sweden)

    Faheem Yousaf

    2014-01-01

    Full Text Available Six Sigma is being Implemented all over the World as a successful Quality Improvement Methodology. Many Companies are now days are using Six Sigma as an Approach towards zero defects. This article provides a practical case study regarding the implementation of Six Sigma Project in a Welding Facility and discusses the Statistical Analysis performed for bringing the welding processes in the desired sigma Limits.DMAIC was chosen as potential Six Sigma methodology with the help of findings of this Methodology, Six Sigma Team First Identified the critical Factors affecting the Process Yield and then certain Improvement Measures were taken to improve the Capability of Individual welding Processes and also of Overall Welding Facility.   Cost of Quality was also measured to Validate the Improvement results achieved after Conducting the Six Sigma Project.

  17. Pulse shaping for all-optical signal processing of ultra-high bit rate serial data signals

    DEFF Research Database (Denmark)

    Palushani, Evarist

    The following thesis concerns pulse shaping and optical waveform manipulation for all-optical signal processing of ultra-high bit rate serial data signals, including generation of optical pulses in the femtosecond regime, serial-to-parallel conversion and terabaud coherent optical time division...

  18. Students' Motivational Processes and Their Relationship to Teacher Ratings in School Physical Education: A Self-Determination Theory Approach

    Science.gov (United States)

    Standage, Martyn; Duda, Joan L.; Ntoumanis, Nikos

    2006-01-01

    In the present study, we used a model of motivation grounded in self-determination theory (Deci & Ryan, 1985, 1991; Ryan & Deci, 2000a, 2000b, 2002) to examine the relationship between physical education (PE) students' motivational processes and ratings of their effort and persistence as provided by their PE teacher. Data were obtained…

  19. A non-permselective membrane reactor for chemical processes normally requiring strict stoichiometric feed rates of reactants

    NARCIS (Netherlands)

    Sloot, H.J.; Versteeg, Geert; van Swaaij, Willibrordus Petrus Maria

    1990-01-01

    A novel type of membrane reactor with separated feeding of the reactants is presented for chemical processes normally requiring strict stoichiometric feed rates of premixed reactants. The reactants are fed in the reactor to the different sides of a porous membrane which is impregnated with a

  20. Modular continuous wavelet processing of biosignals: extracting heart rate and oxygen saturation from a video signal.

    Science.gov (United States)

    Addison, Paul S

    2016-06-01

    A novel method of extracting heart rate and oxygen saturation from a video-based biosignal is described. The method comprises a novel modular continuous wavelet transform approach which includes: performing the transform, undertaking running wavelet archetyping to enhance the pulse information, extraction of the pulse ridge time-frequency information [and thus a heart rate (HRvid) signal], creation of a wavelet ratio surface, projection of the pulse ridge onto the ratio surface to determine the ratio of ratios from which a saturation trending signal is derived, and calibrating this signal to provide an absolute saturation signal (SvidO2). The method is illustrated through its application to a video photoplethysmogram acquired during a porcine model of acute desaturation. The modular continuous wavelet transform-based approach is advocated by the author as a powerful methodology to deal with noisy, non-stationary biosignals in general.

  1. Final Report: "Collaborative Project. Understanding the Chemical Processes That Affect Growth Rates of Freshly Nucleated Particles"

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James N. [NCAR, Boulder, CO (United States); McMurry, Peter H. [NCAR, Boulder, CO (United States)

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate. Our measurements include a self-organized, DOE-ARM funded project at the Southern Great Plains site, the New Particle Formation Study (NPFS), which took place during spring 2013. NPFS data are available to the research community on the ARM data archive, providing a unique suite observations of trace gas and aerosols that are associated with the formation and growth of atmospheric aerosol particles.

  2. Flow rate effect on the structure and morphology of molybdenum oxide nanoparticles deposited by atmospheric-pressure microplasma processing

    International Nuclear Information System (INIS)

    Bose, Arumugam Chandra; Shimizu, Yoshiki; Mariotti, Davide; Sasaki, Takeshi; Terashima, Kazuo; Koshizaki, Naoto

    2006-01-01

    Nanoparticles of crystalline molybdenum oxide were prepared by changing the flow rate of plasma gas (2% oxygen balanced by Ar) using an atmospheric-pressure microplasma technique. The morphology and crystalline structure of the nanoparticles were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The FESEM results revealed that the shape of the deposited nanoparticles depended on the plasma gas flow rate. The TEM results supported the FESEM observations. The transmission electron diffraction (TED) pattern revealed that the obtained nanoparticles changed from MoO 2 to MoO 3 with the flow-rate increase, and correspondingly the nanoparticle size drastically decreased. A process mechanism is proposed from the observations of optical emission spectroscopy (OES) during the process and consumed wire surface analysis from x-ray photoelectron spectroscopy (XPS) and FESEM studies

  3. Statistical Process Control Charts for Measuring and Monitoring Temporal Consistency of Ratings

    Science.gov (United States)

    Omar, M. Hafidz

    2010-01-01

    Methods of statistical process control were briefly investigated in the field of educational measurement as early as 1999. However, only the use of a cumulative sum chart was explored. In this article other methods of statistical quality control are introduced and explored. In particular, methods in the form of Shewhart mean and standard deviation…

  4. 77 FR 72197 - Pears Grown in Oregon and Washington; Assessment Rate Decrease for Processed Pears

    Science.gov (United States)

    2012-12-05

    ... / Wednesday, December 5, 2012 / Rules and Regulations#0;#0; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing..., as amended (7 U.S.C. 601-674), hereinafter referred to as the ``Act.'' The Department of Agriculture...- Washington processed pears. They are familiar with the Committee's needs and with the costs for goods and...

  5. 76 FR 53811 - Pears Grown in Oregon and Washington; Assessment Rate Decrease for Processed Pears

    Science.gov (United States)

    2011-08-30

    ... / Tuesday, August 30, 2011 / Rules and Regulations#0;#0; ] DEPARTMENT OF AGRICULTURE Agricultural Marketing..., as amended (7 U.S.C. 601-674), hereinafter referred to as the ``Act.'' The Department of Agriculture...- Washington processed pears. They are familiar with the Committee's needs and with the costs for goods and...

  6. Effect of process parameters on growth rate and diameter of nano ...

    Indian Academy of Sciences (India)

    Anodic aluminium oxide (AAO) template with hexagonal shaped nano-pores with high aspect ratio was fabricated by two-step anodization processes from high purity aluminium foil. It was observed that pore dimensions were affected by anodizing voltage, electrolyte temperature and the duration of anodization time.

  7. Linking shrimp assemblages with rates of detrital processing along an elevational gradient in a tropical stream

    Science.gov (United States)

    James G. March; Jonathan P. Benstead; Catherine M. Pringle; Mark W. Ruebel

    2001-01-01

    We experimentally excluded freshwater shrimp assemblages (Atyidae, Xiphocarididae, and Palaemonidae) to examine their effects on detrital processing and benthic insect biomass at three sites along an elevational gradient in a tropical stream in Puerto Rico. We also determined which shrimp taxon was responsible for leaf decay in a subsequent laboratory experiment. At...

  8. Analysis of the influence of infeed rate and cutting fluid on cylindrical grinding processes using a conventional wheel

    Directory of Open Access Journals (Sweden)

    Bianchi Eduardo Carlos

    2004-01-01

    Full Text Available New worldwide trends such as globalization have rendered grinding processes increasingly important for industry, making it essential to perform in-depth studies of variations in grinding process parameters in the pursuit of greater cost effectiveness. This paper presents a comparative analysis of three different infeed rates, using a conventional grinding wheel on quenched and tempered D2 steel workpieces. Higher infeed rates are known to be correlated with shorter grinding times, rendering the process more economically attractive. Two different coolant fluids, 5% emulsion and pure oil, were used. The tests were carried out using the smallest possible amount of coolant and an optimized 5 mm diameter nozzle. The parameters analyzed were tangential force, specific energy, acoustic emission, roundness error and surface roughness. The surfaces of the workpieces were also examined by scanning electron microscopy (SEM. The results revealed that increased infeed rates could reduce processing times without compromising the quality of the workpiece profile, thereby reducing the cost of the process. The best cutting fluid, albeit more harmful to human health and less environmentally friendly, was found to be pure oil.

  9. Aggregate Size and Architecture Determine Microbial Activity Balance for One-Stage Partial Nitritation and Anammox

    DEFF Research Database (Denmark)

    Vlaeminck, S.E.; Terada, Akihiko; Smets, Barth F.

    2010-01-01

    and the activity balance for the different aggregate sizes and (ii) to relate aggregate morphology, size distribution, and architecture putatively to the inoculation and operation of the three reactors. A nitrite accumulation rate ratio (NARR) was defined as the net aerobic nitrite production rate divided...... by the anoxic nitrite consumption rate. The smallest reactor A, B, and C aggregates were nitrite sources (NARR, > 1.7). Large reactor A and C aggregates were granules capable of autonomous nitrogen removal (NARR, 0.6 to 1.1) with internal AnAOB zones surrounded by an AerAOB rim. Around 50% of the autotrophic...... space in these granules consisted of AerAOB- and AnAOB-specific extracellular polymeric substances. Large reactor B aggregates were thin film-like nitrite sinks (NARR,

  10. Hourly rate of direct labor - contributions to its applicability in the pricing process inserted in a competitive market

    Directory of Open Access Journals (Sweden)

    Antonio Benedito Silva Oliveira

    2016-12-01

    Full Text Available The detailed cost analysis is currently required as a result of increasingly competitive markets. The strategic cost management, analyzed from the optic of the target costing, can be a powerful tool for companies to keep themselves competitive. In this way, this study aimed to present a meticulous analysis of the hourly rate of direct labor in the pricing process of a new product, in order to understand if its use is appropriate in a pricing process. We used the deductive method supported in a case study, and the result achieved is that the hourly rate of direct current labor cannot be used in the pricing process, otherwise will be determined unrealistic costs to the product. It is important to highlight that this analysis applies to micro and small until large corporations.

  11. Anammox-based systems for nitrogen removal from mainstream municipal wastewater

    OpenAIRE

    Malovanyy, Andriy

    2017-01-01

    Nitrogen removal from municipal wastewater with the application of deammonification process offers an operational cost reduction, especially if it is combined with a maximal use of organic content of wastewater for biogas production. In this thesis, two approaches for integration of the deammonification process into the municipal wastewater treatment scheme were studied. The first approach is based on ammonium concentration from municipal wastewater by ion exchange followed by biological remo...

  12. Modelling Chemical Kinetics of Soybean Oil Transesterification Process for Biodiesel Production: An Analysis of Molar Ratio between Alcohol and Soybean Oil Temperature Changes on the Process Conversion Rate

    Directory of Open Access Journals (Sweden)

    Maicon Tait

    2006-12-01

    Full Text Available A mathematical model describing chemical kinetics of transesterification of soybean oil for biodiesel production has been developed. The model is based on the reverse mechanism of transesterification reactions and describes dynamics concentration changes of triglycerides, diglycerides, monoglycerides, biodiesel, and glycerol production. Reaction rate constants were written in the Arrhenius form. An analysis of key process variables such as temperature and molar ratio soybean oil- alcohol using response surface analysis was performed to achieve the maximum soybean conversion rate to biodiesel. The predictive power of the developed model was checked for the very wide range of operational conditions and parameters values by fitting different experimental results for homogeneous catalytic and non-catalytic processes published in the literature. A very good correlation between model simulations and experimental data was observed.

  13. When do plants modify fluvial processes? Plant-hydraulic interactions under variable flow and sediment supply rates

    Science.gov (United States)

    Manners, Rebecca B.; Wilcox, Andrew C.; Kui, Li; Lightbody, Anne F.; Stella, John C.; Sklar, Leonard S.

    2015-02-01

    Flow and sediment regimes shape alluvial river channels; yet the influence of these abiotic drivers can be strongly mediated by biotic factors such as the size and density of riparian vegetation. We present results from an experiment designed to identify when plants control fluvial processes and to investigate the sensitivity of fluvial processes to changes in plant characteristics versus changes in flow rate or sediment supply. Live seedlings of two species with distinct morphologies, tamarisk (Tamarix spp.) and cottonwood (Populus fremontii), were placed in different configurations in a mobile sand-bed flume. We measured the hydraulic and sediment flux responses of the channel at different flow rates and sediment supply conditions representing equilibrium (sediment supply = transport rate) and deficit (sediment supply plant species and configuration. Species-specific traits controlled the hydraulic response: compared to cottonwood, which has a more tree-like morphology, the shrubby morphology of tamarisk resulted in less pronation and greater reductions in near-bed velocities, Reynolds stress, and sediment flux rates. Under sediment-deficit conditions, on the other hand, abiotic factors dampened the effect of variations in plant characteristics on the hydraulic response. We identified scenarios for which the highest stem-density patch, independent of abiotic factors, dominated the fluvial response. These results provide insight into how and when plants influence fluvial processes in natural systems.

  14. Integrated fixed-film activated sludge ANITA™Mox process--a new perspective for advanced nitrogen removal.

    Science.gov (United States)

    Veuillet, F; Lacroix, S; Bausseron, A; Gonidec, E; Ochoa, J; Christensson, M; Lemaire, R

    2014-01-01

    ANITA™Mox is a Veolia process using moving-bed biofilm reactor (MBBR) technology tested and validated in full-scale for energy- and cost-effective autotrophic N-removal from sidestream effluent using anammox (ANaerobic AMMonium OXidation) bacteria. In order to increase the ANITA™Mox process performances under different operating conditions (e.g. mainstream and sidestream application), substrate transport and accessibility inside the biofilm must be enhanced. In this work, (i) two laboratory scale biofilm ANITA™Mox reactors were operated using different configurations (IFAS - integrated fixed-film activated sludge - and MBBR) and (ii) the distribution of the anammox (AnAOB) and ammonia-oxidizing bacteria (AOB) in the suspended sludge and the biofilm was characterized using molecular tools (qPCR). This study showed that in IFAS configuration, the ANITA™Mox process achieved very high N-removal rate (up to 8 gN/m².d), which was three to four times higher than that achieved in the pure MBBR mode. The high concentration of suspended solids (mixed liquor suspended solids (MLSS)) in the bulk obtained within the IFAS mode induces a very efficient bacterial distribution between the AOB and AnAOB population. AnAOB activity mainly occurs in the biofilm (96% of total AnAOB in the reactor), whereas nitritation by AOB mostly takes place in the suspended phase (93% of total AOB). This spatial distribution observed in the IFAS reactor results from a natural selection due to more easily substrate accessibility for AOB in the bulk (NH4(+), O2) creating higher nitrite concentration in the bulk liquid compare to pure MBBR mode. The efficient control of MLSS level in the IFAS reactor is a key parameter to enhance the nitrite production by AOB and increase the substrate availability in the AnAOB-enriched biofilm leading to higher N-removal rate. These promising results obtained at laboratory scale have been further confirmed in on-going full-scale IFAS ANITA™Mox trials opening

  15. The combined effects of pre- and post-copulatory processes are masking sexual conflict over mating rate in Gerris buenoi.

    Science.gov (United States)

    Devost, E; Turgeon, J

    2016-01-01

    In polygynandrous animals, post-copulatory processes likely interfere with precopulatory sexual selection. In water striders, sexual conflict over mating rate and post-copulatory processes are well documented, but their combined effect on reproductive success has seldom been investigated. We combine genetic parentage analyses and behavioural observations conducted in a competitive reproductive environment to investigate how pre- and post-copulatory processes influence reproductive success in Gerris buenoi Kirkaldy. Precopulatory struggles had antagonistic effects on male and female reproductive success: efficiently gaining copulations was beneficial for males, whereas efficiently avoiding copulations was profitable for females. Also, high mating rates and an intermediate optimal resistance level of females supported the hypothesis of convenience polyandry. Contrary to formal predictions, high mating rates (i.e. the number of copulations) did not increase reproductive success in males or decrease reproductive success in females. Instead, the reproductive success of both sexes was higher when offspring were produced with several partners and when there were few unnecessary matings. Thus, male and female G. buenoi displayed different interests in reproduction, but post-copulatory processes were masking the effects of copulatory mating success on reproductive success. Given the high mating rates observed, sperm competition could easily counter the effect of mating rates, perhaps in interaction with cryptic female choice and/or fecundity selection. Our study presents a complex but realistic overview of sexual selection forces at work in a model organism for the study of sexual conflict, confirming that insights are gained from investigating all episodes in the reproduction cycle of polygynandrous animals. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

  16. Influence of the Chemical Interactions on the Removal Rate of Different Salts in Electrokinetic Desalination Processes

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

    2011-01-01

    Electrokinetic desalination techniques have been successfully applied for the prevention of salt-induced deterioration problems of masonry and other construction materials. A mathematical model for electrochemical desalination treatments is described, based on the Poisson-Nernst-Planck system...... of equations and accounting for the chemical interactions between the species in the pore solution and the solid matrix. Due to their high abundance in the natural environment, chlorides, nitrates and sulfates are considered the main ions responsible to the salt decay processes in buildings materials...

  17. A New Process for Hot Metal Production at Low Fuel Rate - Phase 1 Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Wei-Kao Lu

    2006-02-01

    The project is part of the continuing effort by the North American steel industry to develop a coal-based, cokeless process for hot metal production. The objective of Phase 1 is to determine the feasibility of designing and constructing a pilot scale facility with the capacity of 42,000 mtpy of direct reduced iron (DRI) with 95% metallization. The primary effort is performed by Bricmont, Inc., an international engineering firm, under the supervision of McMaster University. The study focused on the Paired Straight Hearth furnace concept developed previously by McMaster University, The American Iron and Steel Institute and the US Department of Energy.

  18. Insight into the Physical and Dynamical Processes that Control Rapid Increases in Total Flash Rate

    Science.gov (United States)

    Schultz, Christopher J.; Carey, Lawrence D.; Schultz, Elise V.; Blakeslee, Richard J.; Goodman, Steven J.

    2015-01-01

    Rapid increases in total lightning (also termed "lightning jumps") have been observed for many decades. Lightning jumps have been well correlated to severe and hazardous weather occurrence. The main focus of lightning jump work has been on the development of lightning algorithms to be used in real-time assessment of storm intensity. However, in these studies it is typically assumed that the updraft "increases" without direct measurements of the vertical motion, or specification of which updraft characteristic actually increases (e.g., average speed, maximum speed, or convective updraft volume). Therefore, an end-to-end physical and dynamical basis for coupling rapid increases in total flash rate to increases in updraft speed and volume must be understood in order to ultimately relate lightning occurrence to severe storm metrics. Herein, we use polarimetric, multi-Doppler, and lightning mapping array measurements to provide physical context as to why rapid increases in total lightning are closely tied to severe and hazardous weather.

  19. Effects of freezing rates and cryoprotectant on thermal expansion of articular cartilage during freezing process.

    Science.gov (United States)

    Xu, Y; Sun, H J; Lv, Y; Zou, J C; Lin, B L; Hua, T C

    2013-01-01

    The intact articular cartilage has not yet been successfully preserved at low temperature most likely due to the volume expansion from water to ice during freezing. The objective of this current study focuses on examining thermal expansion behavior of articular cartilage (AC) during freezing from 0 degree C to -100 degree C. Thermo Mechanical Analysis (TMA) was used to investigate the effects of different concentrations of dimethyl sulphoxide (DMSO) (0%, 10%, 30% and 60% v/v) and different freezing rates (1 C/min, 3 C/min and 5 C/min). The results showed that: (1) the inhomogeneous thermal expansion (or contraction) presents due to inhomogeneous water distributions in articular cartilage during freezing, which also may be the most likely reason that the matrix has been damaged in cryopreserved intact articular cartilage; (2) at the phase transition temperature range, the maximum thermal strain change value for 5C/min is approximately 1.45 times than that for 1 C/min, but the maximum thermal expansion coefficient of the later is about six times than that of the former; (3) the thermal expansion coefficient decreases with increasing cooling rate at the unfrozen temperature region, but some opposite results are obtained at the frozen temperature region; (4) the higher the DMSO concentration is, at the phase change temperature region, the smaller the thermal strain change as well as the maximum thermal expansion coefficient are, but DMSO concentration exhibits little effect on the thermal expansion coefficient at both unfrozen and frozen region. Once the DMSO concentration increasing enough, e.g. 60% v/v, the thermal strain decreases linearly and smoothly without any abrupt change due to little or no ice crystal forms (i.e. vitrification) in frozen articular cartilage. This study may improve our understanding of the thermal expansion (or contraction) behavior of cryopreserved articular cartilage and it may be useful for the future study on cryopreservation of intact

  20. Denitrification exceeds anammox as a nitrogen loss pathway in the Arabian Sea oxygen minimum zone

    Digital Repository Service at National Institute of Oceanography (India)

    Bulow, S.E.; Rich, J.J.; Naik, H.; Pratihary, A.K.; Ward, B.B.

    was detected at every depth at every station; the maximum rate (25.3 plus or minus 9.1 n mol l sup(-1) d sup(-1) from the sup(15)NO sub(2) tracer and 21.2 plus or minus 5.6 n moll sup(-1) d sup(-1) from the sup(46) N sub(2)O tracer) occurred at the depth...

  1. Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

    Science.gov (United States)

    Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

    2005-01-01

    This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes. PMID:16122390

  2. Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates.

    Science.gov (United States)

    Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

    2005-08-25

    This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL(-1) can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.

  3. Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

    Directory of Open Access Journals (Sweden)

    Karcher Patrick

    2005-08-01

    Full Text Available Abstract This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent or form flocs/aggregates (also called granules without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR, packed bed reactor (PBR, fluidized bed reactor (FBR, airlift reactor (ALR, upflow anaerobic sludge blanket (UASB reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.

  4. A longitudinal study investigating neural processing of speech envelope modulation rates in children with (a family risk for) dyslexia.

    Science.gov (United States)

    De Vos, Astrid; Vanvooren, Sophie; Vanderauwera, Jolijn; Ghesquière, Pol; Wouters, Jan

    2017-08-01

    Recent evidence suggests that a fundamental deficit in the synchronization of neural oscillations to temporal information in speech may underlie phonological processing problems in dyslexia. Since previous studies were performed cross-sectionally in school-aged children or adults, developmental aspects of neural auditory processing in relation to reading acquisition and dyslexia remain to be investigated. The present longitudinal study followed 68 children during development from pre-reader (5 years old) to beginning reader (7 years old) and more advanced reader (9 years old). Thirty-six children had a family risk for dyslexia and 14 children eventually developed dyslexia. EEG recordings of auditory steady-state responses to 4 and 20 Hz modulations, corresponding to syllable and phoneme rates, were collected at each point in time. Our results demonstrate an increase in neural synchronization to phoneme-rate modulations around the onset of reading acquisition. This effect was negatively correlated with later reading and phonological skills, indicating that children who exhibit the largest increase in neural synchronization to phoneme rates, develop the poorest reading and phonological skills. Accordingly, neural synchronization to phoneme-rate modulations was found to be significantly higher in beginning and more advanced readers with dyslexia. We found no developmental effects regarding neural synchronization to syllable rates, nor any effects of a family risk for dyslexia. Altogether, our findings suggest that the onset of reading instruction coincides with an increase in neural responsiveness to phoneme-rate modulations, and that the extent of this increase is related to (the outcome of) reading development. Hereby, dyslexic children persistently demonstrate atypically high neural synchronization to phoneme rates from the beginning of reading acquisition onwards. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Spatial patterns in soil biogeochemical process rates along a Louisiana wetland salinity gradient in the Barataria Bay estuarine system

    Science.gov (United States)

    Roberts, B. J.; Rich, M. W.; Sullivan, H. L.; Bledsoe, R.; Dawson, M.; Donnelly, B.; Marton, J. M.

    2014-12-01

    Louisiana has the highest rates of coastal wetland loss in the United States. In addition to being lost, Louisiana wetlands experience numerous other environmental stressors including changes in salinity regime (both increases from salt water intrusion and decreases from the creation of river diversions) and climate change induced changes in vegetation (e.g. the northward expansion of Avicennia germinans (black mangrove) into salt marshes). In this study, we examined how these changes might influence biogeochemical process rates important in regulating carbon balance and the cycling, retention, and removal of nutrients in Louisiana wetlands. Specifically, we measured net soil greenhouse gas fluxes and collected cores for the determination of rates of greenhouse gas production, denitrification potential, nitrification potential, iron reduction, and phosphorus sorption from surface (0-5cm) and subsurface (10-15cm) depths for three plots in each of 4 sites along the salinity gradient: a freshwater marsh site, a brackish (7 ppt) marsh site, a salt marsh (17 ppt), and a Avicennia germinans stand (17 ppt; adjacent to salt marsh site) in the Barataria Bay estuarine system. Most biogeochemical processes displayed similar spatial patterns with salt marsh rates being lower than rates in freshwater and/or brackish marsh sites and not having significantly different rates than in Avicennia germinans stands. Rates in surface soils were generally higher than in subsurface soils. These patterns were generally consistent with spatial patterns in soil properties with soil water content, organic matter quantity and quality, and extractable nutrients generally being higher in freshwater and brackish marsh sites than salt marsh and Avicennia germinans sites, especially in surface soils. These spatial patterns suggest that the ability of coastal wetlands to retain and remove nutrients might change significantly in response to future climate changes in the region and that these

  6. Is the algorithm used to process heart rate variability data clinically relevant? Analysis in male adolescents.

    Science.gov (United States)

    Soares, Antonio Henrique Germano; Farah, Breno Quintella; Cucato, Gabriel Grizzo; Bastos-Filho, Carmelo José Albanez; Christofaro, Diego Giulliano Destro; Vanderlei, Luiz Carlos Marques; Lima, Aluísio Henrique Rodrigues de Andrade; Ritti-Dias, Raphael Mendes

    2016-01-01

    To analyze whether the algorithm used for the heart rate variability assessment (fast Fourier transform versus autoregressive methods) influenced its association with cardiovascular risk factors in male adolescents. This cross-sectional study included 1,152 male adolescents (aged 14 to 19 years). The low frequency, high frequency components (absolute numbers and normalized units), low frequency/high frequency ratio, and total power of heart rate variability parameters were obtained using the fast Fourier transform and autoregressive methods, while the adolescents were resting in a supine position. All heart rate variability parameters calculated from both methods were different (palgoritmo usado para avaliação da variabilidade da frequência cardíaca (transformada rápida de Fourier versus autoregressivo) influencia em sua associação com fatores de risco cardiovascular adolescentes do gênero masculino. Estudo transversal, que incluiu 1.152 adolescentes do gênero masculino (14 a 19 anos). Componentes de baixa e alta frequência (absolutos e unidades normalizadas), razão componente de baixa frequência/componente de alta frequência e poder total da variabilidade da frequência cardíaca foram obtidos em repouso, na posição supina, usando os métodos transformada rápida de Fourier e autorregressivo. Todos os parâmetros da variabilidade da frequência cardíaca para ambos os métodos foram diferentes (p<0,05). Entretanto, um pequeno tamanho do efeito (<0,1) foi observado para todos os parâmetros. Os coeficientes de correlação intraclasse entre os métodos variaram de 0,96 a 0,99, enquanto os coeficientes de variação foram de 7,4 a 14,8%. A circunferência abdominal foi negativamente associada com o componente de alta frequência, e positivamente associada com o componente de baixa frequência e o balanço simpatovagal (p<0,001 para a transformada rápida de Fourier e o autorregressivo em todas as associações). A pressão arterial sistólica foi

  7. Improved Modeling of Finite-Rate Turbulent Combustion Processes in Research Combustors

    Science.gov (United States)

    VanOverbeke, Thomas J.

    1998-01-01

    The objective of this thesis is to further develop and test a stochastic model of turbulent combustion in recirculating flows. There is a requirement to increase the accuracy of multi-dimensional combustion predictions. As turbulence affects reaction rates, this interaction must be more accurately evaluated. In this work a more physically correct way of handling the interaction of turbulence on combustion is further developed and tested. As turbulence involves randomness, stochastic modeling is used. Averaged values such as temperature and species concentration are found by integrating the probability density function (pdf) over the range of the scalar. The model in this work does not assume the pdf type, but solves for the evolution of the pdf using the Monte Carlo solution technique. The model is further developed by including a more robust reaction solver, by using accurate thermodynamics and by more accurate transport elements. The stochastic method is used with Semi-Implicit Method for Pressure-Linked Equations. The SIMPLE method is used to solve for velocity, pressure, turbulent kinetic energy and dissipation. The pdf solver solves for temperature and species concentration. Thus, the method is partially familiar to combustor engineers. The method is compared to benchmark experimental data and baseline calculations. The baseline method was tested on isothermal flows, evaporating sprays and combusting sprays. Pdf and baseline predictions were performed for three diffusion flames and one premixed flame. The pdf method predicted lower combustion rates than the baseline method in agreement with the data, except for the premixed flame. The baseline and stochastic predictions bounded the experimental data for the premixed flame. The use of a continuous mixing model or relax to mean mixing model had little effect on the prediction of average temperature. Two grids were used in a hydrogen diffusion flame simulation. Grid density did not effect the predictions except

  8. Hawkes process model with a time-dependent background rate and its application to high-frequency financial data

    Science.gov (United States)

    Omi, Takahiro; Hirata, Yoshito; Aihara, Kazuyuki

    2017-07-01

    A Hawkes process model with a time-varying background rate is developed for analyzing the high-frequency financial data. In our model, the logarithm of the background rate is modeled by a linear model with a relatively large number of variable-width basis functions, and the parameters are estimated by a Bayesian method. Our model can capture not only the slow time variation, such as in the intraday seasonality, but also the rapid one, which follows a macroeconomic news announcement. By analyzing the tick data of the Nikkei 225 mini, we find that (i) our model is better fitted to the data than the Hawkes models with a constant background rate or a slowly varying background rate, which have been commonly used in the field of quantitative finance; (ii) the improvement in the goodness-of-fit to the data by our model is significant especially for sessions where considerable fluctuation of the background rate is present; and (iii) our model is statistically consistent with the data. The branching ratio, which quantifies the level of the endogeneity of markets, estimated by our model is 0.41, suggesting the relative importance of exogenous factors in the market dynamics. We also demonstrate that it is critically important to appropriately model the time-dependent background rate for the branching ratio estimation.

  9. Hawkes process model with a time-dependent background rate and its application to high-frequency financial data.

    Science.gov (United States)

    Omi, Takahiro; Hirata, Yoshito; Aihara, Kazuyuki

    2017-07-01

    A Hawkes process model with a time-varying background rate is developed for analyzing the high-frequency financial data. In our model, the logarithm of the background rate is modeled by a linear model with a relatively large number of variable-width basis functions, and the parameters are estimated by a Bayesian method. Our model can capture not only the slow time variation, such as in the intraday seasonality, but also the rapid one, which follows a macroeconomic news announcement. By analyzing the tick data of the Nikkei 225 mini, we find that (i) our model is better fitted to the data than the Hawkes models with a constant background rate or a slowly varying background rate, which have been commonly used in the field of quantitative finance; (ii) the improvement in the goodness-of-fit to the data by our model is significant especially for sessions where considerable fluctuation of the background rate is present; and (iii) our model is statistically consistent with the data. The branching ratio, which quantifies the level of the endogeneity of markets, estimated by our model is 0.41, suggesting the relative importance of exogenous factors in the market dynamics. We also demonstrate that it is critically important to appropriately model the time-dependent background rate for the branching ratio estimation.

  10. Nutritional value and digestion rate of rhea meat proteins in association with storage and cooking processes.

    Science.gov (United States)

    Filgueras, Renata S; Gatellier, Philippe; Ferreira, Claude; Zambiazi, Rui C; Santé-Lhoutellier, Véronique

    2011-09-01

    The nutritional value of proteins was investigated after the storage and cooking of rhea M. Gastrocnemius pars interna. Oxidation of basic and aromatic amino acids, surface hydrophobicity and aggregation state of proteins, were determined in raw and cooked meat. In addition, myofibrillar proteins were exposed in vitro to proteases of the digestive tract. Cooking markedly affected the protein surface hydrophobicity. The BBP bound content was three times greater in cooked than in fresh rhea meat. A small increment in tryptophan content after cooking was observed. Storage influenced Schiff bases formation indicating the presence of protein-aldehyde adducts after cooking. High content of Schiff bases was found after cooking of samples stored for 5 days, demonstrating a probable implication of free amino groups, most likely from lysine. Cooking decreased the myofibrillar protein susceptibility to pepsin activity. After cooking, the proteolysis rate by pancreatic enzymes increased. Our findings support the importance of protein aggregation in the nutritional value of meat proteins. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Effect of various process treatment conditions on the allyl isothiocyanate extraction rate from mustard meal.

    Science.gov (United States)

    Sharma, Harish K; Ingle, Sandeep; Singh, Charanjiv; Sarkar, Bhavesh C; Upadhyay, Ashutosh

    2012-06-01

    Allyl isothiocyanate (AITC), which has the potential to be used as flavoring, antibacterial, antifungal, antifermentative and antibrowning agent in food industry, was extracted from the pretreated MM by distillation technique. The mustard meal was analyzed for the proximate composition and the metals Fe, Mg and Zn. At the optimum pretreatment conditions of temperature 60 °C, time 120 min and pH 4.5, the effect of fractional distillation, mesh size and different additives was studied. Considerable effect of mesh size was observed, as the mesh size was decreased from 1,690 to 400 μm, the allyl isothiocyanate content was increased from 99.15 to 337.11 mg/100 ml. Addition of magnesium chloride (0.05 g/l to 0.2 g/l) and L-ascorbic acid (1 g/l to 5 g/l) increased allyl isothiocyanate from 257.79 to 317.28 mg/100 ml and 316.77 to 396.60 mg/100 ml respectively whereas the addition of the magnesium chloride and L-ascorbic acid in combination did not affect the AITC extraction rate as compare to their addition in single effect.

  12. Process For Controlling Flow Rate Of Viscous Materials Including Use Of Nozzle With Changeable Openings

    Science.gov (United States)

    Ellingson, William A.; Forster, George A.

    1999-11-02

    Apparatus and a method for controlling the flow rate of viscous materials through a nozzle includes an apertured main body and an apertured end cap coupled together and having an elongated, linear flow channel extending the length thereof. An end of the main body is disposed within the end cap and includes a plurality of elongated slots concentrically disposed about and aligned with the flow channel. A generally flat cam plate having a center aperture is disposed between the main body and end cap and is rotatable about the flow channel. A plurality of flow control vane assemblies are concentrically disposed about the flow channel and are coupled to the cam plate. Each vane assembly includes a vane element disposed adjacent the end of the flow channel. Rotation of the cam plate in a first direction causes a corresponding rotation of each of the vane elements for positioning the individual vane elements over the aperture in the end cap blocking flow through the flow channel, while rotation in an opposite direction removes the vane elements from the aperture and positions them about the flow channel in a nested configuration in the full open position, with a continuous range of vane element positions available between the full open and closed positions.

  13. "Rate My Therapist": Automated Detection of Empathy in Drug and Alcohol Counseling via Speech and Language Processing.

    Science.gov (United States)

    Xiao, Bo; Imel, Zac E; Georgiou, Panayiotis G; Atkins, David C; Narayanan, Shrikanth S

    2015-01-01

    The technology for evaluating patient-provider interactions in psychotherapy-observational coding-has not changed in 70 years. It is labor-intensive, error prone, and expensive, limiting its use in evaluating psychotherapy in the real world. Engineering solutions from speech and language processing provide new methods for the automatic evaluation of provider ratings from session recordings. The primary data are 200 Motivational Interviewing (MI) sessions from a study on MI training methods with observer ratings of counselor empathy. Automatic Speech Recognition (ASR) was used to transcribe sessions, and the resulting words were used in a text-based predictive model of empathy. Two supporting datasets trained the speech processing tasks including ASR (1200 transcripts from heterogeneous psychotherapy sessions and 153 transcripts and session recordings from 5 MI clinical trials). The accuracy of computationally-derived empathy ratings were evaluated against human ratings for each provider. Computationally-derived empathy scores and classifications (high vs. low) were highly accurate against human-based codes and classifications, with a correlation of 0.65 and F-score (a weighted average of sensitivity and specificity) of 0.86, respectively. Empathy prediction using human transcription as input (as opposed to ASR) resulted in a slight increase in prediction accuracies, suggesting that the fully automatic system with ASR is relatively robust. Using speech and language processing methods, it is possible to generate accurate predictions of provider performance in psychotherapy from audio recordings alone. This technology can support large-scale evaluation of psychotherapy for dissemination and process studies.

  14. Sensitivity of Induced Seismic Sequences to Rate-and-State Frictional Processes

    Science.gov (United States)

    Kroll, Kayla A.; Richards-Dinger, Keith B.; Dieterich, James H.

    2017-12-01

    It is well established that subsurface injection of fluids increases pore fluid pressures that may lead to shear failure along a preexisting fault surface. Concern among oil and gas, geothermal, and carbon storage operators has risen dramatically over the past decade due to the increase in the number and magnitude of induced earthquakes. Efforts to mitigate the risk associated with injection-induced earthquakes include modeling of the interaction between fluids and earthquake faults. Here we investigate this relationship with simulations that couple a geomechanical reservoir model and RSQSim, a physics-based earthquake simulator. RSQSim employs rate- and state-dependent friction (RSF) that enables the investigation of the time-dependent nature of earthquake sequences. We explore the effect of two RSF parameters and normal stress on the spatiotemporal characteristics of injection-induced seismicity. We perform >200 simulations to systematically investigate the effect of these model components on the evolution of induced seismicity sequences and compare the spatiotemporal characteristics of our synthetic catalogs to observations of induced earthquakes. We find that the RSF parameters control the ability of seismicity to migrate away from the injection well, the total number and maximum magnitude of induced events. Additionally, the RSF parameters control the occurrence/absence of premonitory events. Lastly, we find that earthquake stress drops can be modulated by the normal stress and/or the RSF parameters. Insight gained from this study can aid in further development of models that address best practice protocols for injection operations, site-specific models of injection-induced earthquakes, and probabilistic hazard and risk assessments.

  15. Influence of Groundwater Flow Rate on Nuclide Releases from Pyro-processed Waste Repository

    International Nuclear Information System (INIS)

    Lee, Youn Myoung; Jeong, Jong Tae

    2011-01-01

    Since the early 2000s several template programs for the safety assessment of a high-level radioactive waste repository as well as a low- and intermediate level radioactive waste repository systems have been developed by utilizing GoldSim and AMBER at KAERI. Very recently, another template program for a conceptual hybrid-typed repository system, called 'A-KRS' in which two kinds of pyroprocessed radioactive wastes, low-level metal wastes and ceramic high-level wastes that arise from pyroprocessing of PWR nuclear spent fuels has been developed and are to be disposed of by separate disposal strategies. The A-KRS is considered to be constructed at two different depths in geological media: 200m depth, at which a possible human intrusion is considered to be limited after closure, for the pyroprocessed metal wastes with lower or no decay heat producing nuclides, and 500m depth, believed to be in the reducing condition for nuclides with a rather higher radioactivity and heat generation rate. This program is ready for total system performance assessment which is able to evaluate nuclide release from the repository and farther transport into the geosphere and biosphere under various normal, disruptive natural and manmade events, and scenarios that can occur after a failure of waste package and canister. To quantify a nuclide release and transport through the possible various pathways especially in the near-fields of the A-KRS repository system, some illustrative evaluations have been made through the study. Even though all parameter values associated with the A-KRS were assumed for the time being, the illustrative results should be informative since the evaluation of such releases is very important not only in view of the safety assessment of the repository, but also for design feedback of its performance

  16. Impact of different cutoff criteria on rate of (central auditory processing disorders diagnosis using the central test battery

    Directory of Open Access Journals (Sweden)

    Mohsin Ahmed Shaikh

    2016-11-01

    Full Text Available The purpose of this study was to quantify how the use of two different cutoff criteria affects the test failure rate and potential diagnosis of central auditory processing disorder ([C]APD in a sample of children subjected to central auditory processing ([C]AP assessment. Test failure rates for the central test battery (CTB using two different cutoff criteria (1 and 2 SDs below the mean were measured retrospectively for 98 children who completed (CAP assessment. The rates of potential (CAPD diagnosis ranged from 86.8% [when a 1 standard deviation (SD cutoff was used] to 66.2% (when a 2 SD cutoff was used. The current use of two different cutoffs for the CTB has a large impact on the diagnostic rate for (CAPD. These findings have clinical implications for the diagnosis of (CAPD due to the widespread use of the CTB in the United States for the assessment of (CAPD in children. Thus, it is important to create awareness among audiologists that use of the 2 SDs cutoff criterion is recommended for reducing false positives (error.

  17. The effect of coarse second-phase particles on the rate of grain refinement during severe deformation processing

    DEFF Research Database (Denmark)

    Apps, P.J.; Bowen, Jacob R.; Prangnell, P.B.

    2003-01-01

    The effect of second-phase particles on the rate of grain refinement during severe deformation processing has been investigated, by comparing the microstructure evolution in an AA8079 aluminium alloy, containing 2.5 vol.% of ~2 μm particles, with that in a high purity, single-phase, Al-0.13% Mg a...... by an effective strain of only five in the particle-containing alloy, compared to ten in the single-phase material. The mechanisms that contribute to this acceleration of the grain refinement process are discussed.......The effect of second-phase particles on the rate of grain refinement during severe deformation processing has been investigated, by comparing the microstructure evolution in an AA8079 aluminium alloy, containing 2.5 vol.% of ~2 μm particles, with that in a high purity, single-phase, Al-0.13% Mg...... alloy, deformed identically by ECAE to an effective strain of ten. The materials were analysed by high-resolution EBSD orientation mapping, which revealed that grain refinement occurred at a dramatically higher rate in the particle-containing alloy. A submicron grain structure could be achieved...

  18. Preliminary Assessment of Growth Rates on Different Concentration of Microalgae Scenedesmus sp. in Industrial Meat Food Processing Wastewater

    Directory of Open Access Journals (Sweden)

    Latiffi Nur Atikah Ahmad

    2017-01-01

    Full Text Available This study is aimed to evaluate and access the growth rates and biomass productivity in different concentrations of microalgae Scenedesmus sp. using Industrial Meat Food Processing Wastewater as a media. The focus of this study is to determine the best concentrations of microalgae Scenedesmus sp. in raw wastewater in terms of kinetics of cells growth rates. The study verified that concentration of 1×106 cells/ml of microalgae gives the highest specific growth rates of biomass at 0.4488 day-1 and 1720 cells/ml/day compare to the other concentrations, while the lowest occurred at concentration of 1×103 cells/ml at 0.4108 day-1 and 14.9 cells/ml/day. The result shows the different concentration of microalgae Scenedesmus sp. culturing in Industrial Food Processing Wastewater influence the cells growth of biomass and the optimum were obtained at concentration of 1×106 cells/ml which suggested use for Industrial Meat Food Processing Wastewater Treatment purposed. With this finding, it should be seemly to adopt and applied efficiently in treating the wastewater especially for Scenedesmus sp. type of microalgae.

  19. High rates of denitrification and nitrous oxide emission in arid biological soil crusts from the Sultanate of Oman.

    Science.gov (United States)

    Abed, Raeid M M; Lam, Phyllis; de Beer, Dirk; Stief, Peter

    2013-09-01

    Using a combination of process rate determination, microsensor profiling and molecular techniques, we demonstrated that denitrification, and not anaerobic ammonium oxidation (anammox), is the major nitrogen loss process in biological soil crusts from Oman. Potential denitrification rates were 584±101 and 58±20 μmol N m(-2) h(-1) for cyanobacterial and lichen crust, respectively. Complete denitrification to N2 was further confirmed by an (15)NO3(-) tracer experiment with intact crust pieces that proceeded at rates of 103±19 and 27±8 μmol N m(-2) h(-1) for cyanobacterial and lichen crust, respectively. Strikingly, N2O gas was emitted at very high potential rates of 387±143 and 31±6 μmol N m(-2) h(-1) from the cyanobacterial and lichen crust, respectively, with N2O accounting for 53-66% of the total emission of nitrogenous gases. Microsensor measurements revealed that N2O was produced in the anoxic layer and thus apparently originated from incomplete denitrification. Using quantitative PCR, denitrification genes were detected in both the crusts and were expressed either in comparable (nirS) or slightly higher (narG) numbers in the cyanobacterial crusts. Although 99% of the nirS sequences in the cyanobacterial crust were affiliated to an uncultured denitrifying bacterium, 94% of these sequences were most closely affiliated to Paracoccus denitrificans in the lichen crust. Sequences of nosZ gene formed a distinct cluster that did not branch with known denitrifying bacteria. Our results demonstrate that nitrogen loss via denitrification is a dominant process in crusts from Oman, which leads to N2O gas emission and potentially reduces desert soil fertility.

  20. Entropic formulation for the protein folding process: Hydrophobic stability correlates with folding rates

    Science.gov (United States)

    Dal Molin, J. P.; Caliri, A.

    2018-01-01

    possible connection between the hydrophobic component of protein stability and the native structural topology. We simulated those same 200 targets again with the Mq A, only. However, this time we evaluated the relative frequency {ϕq } in which each target visits its corresponding native structure along an appropriate simulation time. Due to the presence of the hydrophobic effect in our approach we obtained a strong correlation between the stability and the folding rate (R = 0 . 85). So, as faster a sequence found its target, as larger is the hydrophobic component of its stability. The strong correlation fulfills our last goal. This final finding suggests that the hydrophobic effect could not be a general stabilizing factor for proteins.

  1. A Binaural CI Research Platform for Oticon Medical SP/XP Implants Enabling ITD/ILD and Variable Rate Processing

    Science.gov (United States)

    Adiloğlu, K.; Herzke, T.

    2015-01-01

    We present the first portable, binaural, real-time research platform compatible with Oticon Medical SP and XP generation cochlear implants. The platform consists of (a) a pair of behind-the-ear devices, each containing front and rear calibrated microphones, (b) a four-channel USB analog-to-digital converter, (c) real-time PC-based sound processing software called the Master Hearing Aid, and (d) USB-connected hardware and output coils capable of driving two implants simultaneously. The platform is capable of processing signals from the four microphones simultaneously and producing synchronized binaural cochlear implant outputs that drive two (bilaterally implanted) SP or XP implants. Both audio signal preprocessing algorithms (such as binaural beamforming) and novel binaural stimulation strategies (within the implant limitations) can be programmed by researchers. When the whole research platform is combined with Oticon Medical SP implants, interaural electrode timing can be controlled on individual electrodes to within ±1 µs and interaural electrode energy differences can be controlled to within ±2%. Hence, this new platform is particularly well suited to performing experiments related to interaural time differences in combination with interaural level differences in real-time. The platform also supports instantaneously variable stimulation rates and thereby enables investigations such as the effect of changing the stimulation rate on pitch perception. Because the processing can be changed on the fly, researchers can use this platform to study perceptual changes resulting from different processing strategies acutely. PMID:26721923

  2. Determination of Chemical Kinetic Rate Constants of a Model for Carbothermal Processing of Lunar Regolith Simulant Using Methane

    Science.gov (United States)

    Balasubramaniam, R; Gokoglu, S.; Hegde, U.

    2009-01-01

    We have previously developed a chemical conversion model of the carbothermal processing of lunar regolith using methane to predict the rate of production of carbon monoxide. In this carbothermal process, gaseous methane is pyrolyzed as it flows over the hot surface of a molten zone of lunar regolith and is converted to carbon and hydrogen. Hydrogen is carried away by the exiting stream of gases and carbon is deposited on the melt surface. The deposited carbon mixes with the melt and reacts with the metal oxides in it to produce carbon monoxide that bubbles out of the melt. In our model, we assume that the flux of carbon deposited is equal to the product of the surface reaction rate constant gamma and the concentration of methane adjacent to the melt surface. Similarly, the rate of consumption of carbon per unit volume in the melt is equal to the product of the melt reaction rate constant k and the concentrations of carbon and metal oxide in the melt. In this paper, we describe our effort to determine gamma and k by comparison of the predictions from our model with test data obtained by ORBITEC (Orbital Technologies Corporation). The concentration of methane adjacent to the melt surface is a necessary input to the model. It is inferred from the test data by a mass balance of methane, adopting the usual assumptions of the continuously-stirred-tank-reactor model, whereby the average concentration of a given gaseous species equals its exit concentration. The reaction rates gamma and k have been determined by a non-linear least-squares fit to the test data for the production of carbon monoxide and the fraction of the incoming methane that is converted. The comparison of test data with our model predictions using the determined chemical kinetic rate constants provides a consistent interpretation of the process over the full range of temperatures, pressures, and methane flow rates used in the tests, thereby increasing our confidence to use the model for scale-up purposes.

  3. Pathways and Controls of N2O Production in Nitritation-Anammox Biomass

    DEFF Research Database (Denmark)

    Ma, Chun; Jensen, Marlene Mark; Smets, Barth F.

    2017-01-01

    of N2O production from hydroxylamine oxidation at low O2 was unexpected and suggests that more than one enzymatic pathway may be involved in this process. N2O production by hydroxylamine oxidation was further stimulated by NH4+, whereas nitrifier denitrification at low O2 levels was stimulated by NO2...... contributed substantially to N2O accumulation across a wide range of conditions with varying concentrations of O2, NH4+, and NO2-. The O2 concentration exerted the strongest control on net N2O production with both production pathways stimulated by low O2, independent of NO2- concentrations. The stimulation......- at levels as low as 0.2 mM. Our study shows that 15N and 18O isotope labeling is a useful approach for direct quantification of N2O production pathways applicable to diverse environments....

  4. A user configurable data acquisition and signal processing system for high-rate, high channel count applications

    International Nuclear Information System (INIS)

    Salim, Arwa; Crockett, Louise; McLean, John; Milne, Peter

    2012-01-01

    Highlights: ► The development of a new digital signal processing platform is described. ► The system will allow users to configure the real-time signal processing through software routines. ► The architecture of the DRUID system and signal processing elements is described. ► A prototype of the DRUID system has been developed for the digital chopper-integrator. ► The results of acquisition on 96 channels at 500 kSamples/s per channel are presented. - Abstract: Real-time signal processing in plasma fusion experiments is required for control and for data reduction as plasma pulse times grow longer. The development time and cost for these high-rate, multichannel signal processing systems can be significant. This paper proposes a new digital signal processing (DSP) platform for the data acquisition system that will allow users to easily customize real-time signal processing systems to meet their individual requirements. The D-TACQ reconfigurable user in-line DSP (DRUID) system carries out the signal processing tasks in hardware co-processors (CPs) implemented in an FPGA, with an embedded microprocessor (μP) for control. In the fully developed platform, users will be able to choose co-processors from a library and configure programmable parameters through the μP to meet their requirements. The DRUID system is implemented on a Spartan 6 FPGA, on the new rear transition module (RTM-T), a field upgrade to existing D-TACQ digitizers. As proof of concept, a multiply-accumulate (MAC) co-processor has been developed, which can be configured as a digital chopper-integrator for long pulse magnetic fusion devices. The DRUID platform allows users to set options for the integrator, such as the number of masking samples. Results from the digital integrator are presented for a data acquisition system with 96 channels simultaneously acquiring data at 500 kSamples/s per channel.

  5. Australia's Health Star Rating policy process: Lessons for global policy-making in front-of-pack nutrition labelling.

    Science.gov (United States)

    Kumar, Medha; Gleeson, Deborah; Barraclough, Simon

    2017-11-12

    This study explored factors that shaped the development of Australia's Health Star Rating system for front-of-pack labelling (FoPL) on packaged foods and whether insights could be drawn from this experience to inform the development of global FoPL standards. Ten individual semi-structured interviews were conducted with public health or consumer advocates, academics in the field of nutrition labelling and policy, a food industry employee, and Australian public servants. Thematic analysis was undertaken, guided by Kingdon's Multiple Streams Framework, to identify factors which shaped Australian and international FoPL policy processes. Senior Australian bureaucrats played the policy entrepreneur role to facilitate the development of the Health Star Rating system. The public health and consumer advocacy groups formed an alliance to counter-balance the influence of the food industry in the Health Star Rating development process. Public health and consumer groups have less influence at Codex Alimentarius, where policy-making is constrained by political alliances and consensus voting structures. Strong leadership, policy entrepreneurship and a coherent alliance between public health and consumer groups enabled the development of a FoPL system in Australia and could contribute to advancing FoPL standards at the international level. © 2017 Dietitians Association of Australia.

  6. Amorphization and Frictional Processes in Smectite-Quartz Gouge Mixtures Sheared from Sub-seismic to Seismic Slip Rates

    Science.gov (United States)

    Aretusini, S.; Mittempergher, S.; Spagnuolo, E.; Di Toro, G.; Gualtieri, A.; Plümper, O.

    2015-12-01

    Slipping zones in shallow sections of megathrusts and large landslides are often made of smectite and quartz gouge mixtures. Experiments aimed at investigating the frictional processes operating at high slip rates (>1 m/s) may unravel the mechanics of these natural phenomena. Here we present a new dataset obtained with two rotary shear apparatus (ROSA, Padua University; SHIVA, INGV-Rome). Experiments were performed at room humidity and temperature on four mixtures of smectite (Ca-Montmorillonite) and quartz with 68, 50, 25, 0 wt% of smectite. The gouges were slid for 3 m at normal stress of 5 MPa and slip rate V from 300 µm/s to 1.5 m/s. Temperature during the experiments was monitored with four thermocouples and modeled with COMSOL Multiphysics. In smectite-rich mixtures, the friction coefficient µ evolved with slip according to three slip rate regimes: in regime 1 (V0.3 m/s) µ had strong slip-weakening behavior. Instead, in quartz-rich mixtures the gouge had a monotonic slip-weakening behavior, independently of V. Temperature modelling showed that the fraction of work rate converted into heat decreased with increasing smectite content and slip rate. Quantitative X-ray powder diffraction (Rietveld method) indicates that the production of amorphous material from smectite breakdown increased with frictional work but was independent of work rate. Scanning Electron Microscopy investigation evidenced strain localization and presence of dehydrated clays for V≥0.3 m/s; instead, for V<0.3 m/s, strain was distributed and the gouge layer pervasively foliated. In conclusion, amorphization of the sheared gouges was not responsible of the measured frictional weakening. Instead, slip-weakening was concomitant to strain localization and possible vaporization of water adsorbed on smectite grain surfaces.

  7. New types of coating systems for steel sheets by high-rate evaporation in combination with plasma processes

    Energy Technology Data Exchange (ETDEWEB)

    Scheffel, B.; Metzner, C. [Fraunhofer-Institut fuer Elektronenstrahl und Plasmatechnik (FEP), Dresden (Germany); Ehlers, K.D. [Salzgitter AG Stahl und Technologie (Germany); Schuhmacher, B. [Dortmunder Oberflaechencentrum GmbH, Dortmund (Germany); Flossdorf, F.J.; Steinbeck, G. [Verein Deutscher Eisenhuettenleute (VDEh), Duesseldorf (Germany); Steffen, R. [Stahlwerke Bremen GmbH (Germany); Hagler, J. [voestalpine Stahl GmbH, Linz (Austria)

    2002-03-01

    High-rate evaporation in combination with plasma processes is a promising approach to obtain new types of steel sheet coating with improved corrosion resistance and application properties. To estimate the potential for the application of PVD-coatings (physical vapour deposition) different coating systems for steel sheet as well as for hot-dip or electro-galvanized steel sheet were designed. The samples were produced on a laboratory scale using PVD processes with very high deposition rates (in the order of 1 {mu}m s{sup -1}) as well as high-power plasma processes for the pre-treatment. The relationship between the composition, microstructure and properties of the coating systems, in particular concerning corrosion protection, abrasion during forming, phosphating and paint adhesion, were studied. It was found that the corrosion resistance of galvanized steel sheets can be considerably improved by vapour deposition of metal or inorganic films with a thickness of several hundred nanometers. Investigations on vapour deposition of titanium and stainless steel coatings on steel sheets, for applications in a severely corrosive environment, showed that the corrosion resistance in relation to the coating thickness can be significantly enhanced by means of plasma activation during the vapour deposition process. Finally, an outlook on possible industrial applications including an estimation of the process costs will be presented. For certain coating systems the results look promising. Consequently, these particular coating systems will be investigated in more detail by means of using a large-scale in-line deposition plant for metallic strips and sheets. (orig.)

  8. Influence of biogas flow rate on biomass composition during the optimization of biogas upgrading in microalgal-bacterial processes.

    Science.gov (United States)

    Serejo, Mayara L; Posadas, Esther; Boncz, Marc A; Blanco, Saúl; García-Encina, Pedro; Muñoz, Raúl

    2015-03-03

    The influence of biogas flow rate (0, 0.3, 0.6, and 1.2 m(3) m(-2) h(-1)) on the elemental and macromolecular composition of the algal-bacterial biomass produced from biogas upgrading in a 180 L photobioreactor interconnected to a 2.5 L external bubbled absorption column was investigated using diluted anaerobically digested vinasse as cultivation medium. The influence of the external liquid recirculation/biogas ratio (0.5 biogas, was also evaluated. A L/G ratio of 10 was considered optimum to support CO2 and H2S removals of 80% and 100%, respectively, at all biogas flow rates tested. Biomass productivity increased at increasing biogas flow rate, with a maximum of 12 ± 1 g m(-2) d(-1) at 1.2 m(3) m(-2) h(-1), while the C, N, and P biomass content remained constant at 49 ± 2%, 9 ± 0%, and 1 ± 0%, respectively, over the 175 days of experimentation. The high carbohydrate contents (60-76%), inversely correlated to biogas flow rates, would allow the production of ≈100 L of ethanol per 1000 m(3) of biogas upgraded under a biorefinery process approach.

  9. The Impact of Warm-Rain Microphysical Processes on Rain Rate and Polarimetric Observables at X-Band

    Science.gov (United States)

    Xie, Xinxin; Evaristo, Raquel; Troemel, Silke; Simmer, Clemens

    2015-04-01

    Microphysical processes govern the evolution of drop size distribution (DSD) during the development of precipitating systems. Thus, an accurate knowledge on precipitating systems from a microphysical perspective is required for better quantitative precipitation estimates (QPE). Additionally, detection of microphysical processes in 3D polarimetric radar volumes paves the way for better parameterizations in numerical weather predictions (NWP). In this study, we focus on the impact of different microphysical processes on rain rate (RR) and polarimetric observables at X band. Microphysical processes during the evolution of warm-rain precipitating systems, including size sorting, evaporation, coalescence and breakup, are taken into account. Assuming that vertical rain shaft is composed of liquid spheroids distributed in a normalized Gamma size distribution, microphysical processes are reconstructed. The variation of RR governed by microphysical processes is also examined. Unique fingerprints caused by microphysical processes have been identified in polarimetric radar observations. For size sorting, large rain drops concentrating near ground surface or at leading edge induce strong Zdr (differential reflectivity) accompanied by small Zh (reflectivity). A larger mean size in DSD results in stronger Zdr during size sorting. The increasing mean size due to evaporation and coalescence enhances Zdr, while Zh during evaporation is reduced by the depletion of small rain drops. The reduction of Zh ranges between -10 dB and 0 dB considering different DSDs during evaporation. Zh, Zdr and Kdp (specific differential phase) all decrease when large rain drops break up. The evolution of DSD which depends on the ongoing microphysical processes results in a variation in RR. Though size sorting due to differential sedimentation occurs, RR approaches stable within 15 min. Suffering from vertical wind shear, RR is reduced because of the categorization of rain drops with different terminal

  10. Effect of Temperature on Precipitation Rate of Calcium Carbonate Produced through Microbial Metabolic Process of Bio Materials

    Directory of Open Access Journals (Sweden)

    Prima Yane Putri

    2016-09-01

    Full Text Available Concrete is the most widely used construction material in civil engineering. But plain concrete is a brittle material and has little resistance to cracking. The cracking in concrete promotes deterioration such as the corrosion of reinforcing rebar, therefore, repair in filling the crack is often carried out. Recently, repair methods using bio-based materials associated with microbial metabolic processes leading to precipitation of calcium carbonate have been intensively studied. In this study, influencing factors on the precipitation rate depending on the constituents of bio-based material comprising yeast, glucose and calcium acetate mixed in tris buffer solution was examined for improving the rate of initial reactions. In addition, effect of temperature change on the amount of calcium carbonate precipitation was also investigated. The precipitates were identified by X-ray diffraction. It was shown that the increase of temperature lead to a change on calcium carbonate precipitation and caused the pH decrease under 7.0.

  11. Increased delignification rate of Dendrocalamus strictus (Roxburgh nees by Schizophyllum commune Fr.; Fr. to reduce chemical consumption during pulping process

    Directory of Open Access Journals (Sweden)

    Vipin Kumar Saini

    2013-08-01

    Full Text Available Pulp and paper industry is traditionally known to be a large contributor to environmental pollution due its largeconsumption of energy and chemicals. To reduce the chemical consumption, rate of delignification was increased bySchizophyllum commune in destructured sample of Dendrocalamus stictus, which was destructured by Impressafiner (compression-cum dewatering process. The extent of delignification was determined and comparison was made between thenon-destructured and destructured samples. The influence of physical parameters like incubation time, moisture level, media,media concentration, pH and temperature were also examined during the study. It was found that rate of delignification wassignificantly 6.43% more in destructured sample than non-destructured sample. Kraft pulping of treated destructured sampleshows 2.59 point reduction in kappa number than untreated non-destructured sample. Thus this paper provides an insight ofthe delignification extent in Dendrocalamus strictus after mechanical operation at varying physical parameters.

  12. Processing and characterization of aluminium alloys or composites exhibiting low-temperature or high-rate superplasticity

    International Nuclear Information System (INIS)

    Huang, J. C.

    1997-01-01

    Wide applications of superplastic forming still face several problems, one is the high temperature that promotes grain growth, another is the low forming rate that makes economically inefficient. The current study is intended to develop a series of fabrication and thermomechanical processing, so as to result in materials possessing either low temperature superplasticity (LTSP) or high rate superplasticity (HRSP). The former has been achieved in the cast Al alloys, while the latter was accomplished in powder-metallurgy aluminium matrix composites. The aluminium alloys, after special thermomechanical processes, exhibited LTSP from 300 to 450 degree C with elongations varying from 300 to 700 %. The LTSP sheets after 700 % elongation at 350 degree C still possessed fine grains 3.7 μm size and narrow surface solute depletion zones 11 μm in with, resulting in a post-SP T6 strength of 500 MPa, significantly higher than that of the HTSP superplasticity alloys tested at 525 degree C or above. Meanwhile, it was found that LTSP materials may be transferred into HTSP materials simply by adding a preloading at 300-400 degree C for a small amount of work. As for the endeavor in making HRSP materials, 2024Al/SiC, 6061Al/SiC and Al/Al 3 Ti systems processed by powder metallurgy or mechanical alloying methods are under investigation. The average sizes of the reinforcing SiC or A13Ti particles, as well as the grain size are all around 1 μm. The aluminium composites have exhibited HRSP at 525-620 degree C and 10 -2 -10 -1 s -l , with elongations varying from 150 to 350 %. This ultimate goal is to produce an alloy or composite exhibiting low temperature and high strain rate superplasticity (LT and HRSP). (author)

  13. Implications of alteration processes on radon emanation, radon production rate and W-Sn exploration in the Panasqueira ore district.

    Science.gov (United States)

    Domingos, Filipa; Pereira, Alcides

    2018-05-01

    Alteration processes have strong impacts on the chemical and physical properties of rock masses. Because they can affect the contents and the distribution of U as well as enhance the permeability of the bedrock, they may lead to a significant increase of radon release to the environment. However, their influence on radon emanation and radon production rate has yet to be properly assessed. To investigate the impact of alteration processes on the radiological properties, samples were collected in the Panasqueira region under the influence of surface weathering, deuteric, hydrothermal and fault related alteration. Major and trace elements (U, Th), physical, and radiological properties were measured in metasedimentary and fault rocks. The degree of alteration and weathering progress were assessed through indices of alteration, porosity and bulk density. Overall, an increase of the radon emanation coefficient from (approximately) 0.1 to 0.4 and radon production rate (from 40 to over 160Bq·m -3 ·h -1 ) is observed with the progress of physicochemical alteration. Decoupling of physical and chemical alteration however implies both must be quantified towards a proper assessment of the degree of alteration. The behavior of radiogenic elements upon alteration is shown to be complex and contingent upon the alteration process. An atypical increase of radon emanation in the ore district due to U mobilization was caused by hydrothermal alteration. Because radon emanation is not dependent upon the pelitic nature of the metasedimentary rocks, it may thus become a proxy for W-Sn exploration. The dependency of radon production rate from the latter constrains its use for exploration. Nevertheless, it may provide a reliable estimation of the bedrock contribution to indoor radon concentrations. Higher indoor radon concentrations, hence, a higher risk of exposure to radon are expected in the ore district as well as within fault zones. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Controlling the COD removal of an A-stage pilot study with instrumentation and automatic process control.

    Science.gov (United States)

    Miller, Mark W; Elliott, Matt; DeArmond, Jon; Kinyua, Maureen; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

    2017-06-01

    The pursuit of fully autotrophic nitrogen removal via the anaerobic ammonium oxidation (anammox) pathway has led to an increased interest in carbon removal technologies, particularly the A-stage of the adsorption/bio-oxidation (A/B) process. The high-rate operation of the A-stage and lack of automatic process control often results in wide variations of chemical oxygen demand (COD) removal that can ultimately impact nitrogen removal in the downstream B-stage process. This study evaluated the use dissolved oxygen (DO) and mixed liquor suspended solids (MLSS) based automatic control strategies through the use of in situ on-line sensors in the A-stage of an A/B pilot study. The objective of using these control strategies was to reduce the variability of COD removal by the A-stage and thus the variability of the effluent C/N. The use of cascade DO control in the A-stage did not impact COD removal at the conditions tested in this study, likely because the bulk DO concentration (>0.5 mg/L) was maintained above the half saturation coefficient of heterotrophic organisms for DO. MLSS-based solids retention time (SRT) control, where MLSS was used as a surrogate for SRT, did not significantly reduce the effluent C/N variability but it was able to reduce COD removal variation in the A-stage by 90%.

  15. Brunovsky Normal Form of Monod Kinetics Models and Growth Rate Control of a Fed-batch Cultivation Process

    Directory of Open Access Journals (Sweden)

    Pavlov Y.

    2007-12-01

    Full Text Available A mathematical methodology that gives assistance to design of fed-batch stabilization and control is presented. The methodology is based both on Utility theory and optimal Control theory. The Utility theory deals with the expressed subjective preferences and allows for the expert preferences to be taken in consideration in complex biotechnological systems as criteria for control and optimization. The Control theory is used for parameters stabilization of a fed-batch cultivation process. The control is written based on information of the growth rate. The simulations show good efficiency of the control laws.

  16. Manganese reduction/oxidation reaction on graphene composites as a reversible process for storing enormous energy at a fast rate

    OpenAIRE

    Chen, Yanyi; Xu, Chengjun; Shi, Shan; Li, Jia; Kang, Feiyu; Wei, Chunguang

    2014-01-01

    Oxygen reduction/evolution reaction (ORR/OER) is a basic process for fuel cells or metal air batteries. However, ORR/OER generally requires noble metal catalysts and suffers from low solubility (10-3 molar per liter) of O2, low kinetics rate (10-6 cm2/s) and low reversibility. We report a manganese reduction/oxidation reaction (MRR/MOR) on graphene/MnO2 composites, delivering a high capacity (4200 mAh/g), fast kinetics (0.0024 cm2/s, three orders higher than ORR/OER), high solubility (three o...

  17. Nitrogen source effects on the denitrifying anaerobic methane oxidation culture and anaerobic ammonium oxidation bacteria enrichment process.

    Science.gov (United States)

    Fu, Liang; Ding, Jing; Lu, Yong-Ze; Ding, Zhao-Wei; Zeng, Raymond J

    2017-05-01

    The co-culture system of denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (Anammox) has a potential application in wastewater treatment plant. This study explored the effects of permutation and combination of nitrate, nitrite, and ammonium on the culture enrichment from freshwater sediments. The co-existence of NO 3 - , NO 2 - , and NH 4 + shortened the enrichment time from 75 to 30 days and achieved a total nitrogen removal rate of 106.5 mg/L/day on day 132. Even though ammonium addition led to Anammox bacteria increase and a higher nitrogen removal rate, DAMO bacteria still dominated in different reactors with the highest proportion of 64.7% and the maximum abundance was 3.07 ± 0.25 × 10 8 copies/L (increased by five orders of magnitude) in the nitrite reactor. DAMO bacteria showed greater diversity in the nitrate reactor, and one was similar to M. oxyfera; DAMO bacteria in the nitrite reactor were relatively unified and similar to M. sinica. Interestingly, no DAMO archaea were found in the nitrate reactor. This study will improve the understanding of the impact of nitrogen source on DAMO and Anammox co-culture enrichment.

  18. The effect of narrow-band digital processing and bit error rate on the intelligibility of ICAO spelling alphabet words

    Science.gov (United States)

    Schmidt-Nielsen, Astrid

    1987-08-01

    The recognition of ICAO spelling alphabet words (ALFA, BRAVO, CHARLIE, etc.) is compared with diagnostic rhyme test (DRT) scores for the same conditions. The voice conditions include unprocessed speech; speech processed through the DOD standard linear-predictive-coding algorithm operating at 2400 bit/s with random error rates of 0, 2, 5, 8, and 12 percent; and speech processed through an 800-bit/s pattern-matching algorithm. The results suggest that, with distinctive vocabularies, word intelligibility can be expected to remain high even when DRT scores fall into the poor range. However, once the DRT scores fall below 75 percent, the intelligibility can be expected to fall off rapidly; at DRT scores below 50, the recognition of a distinctive vocabulary should also fall below 50 percent.

  19. Yarn supplier selection using analytical hierarchy process (AHP) and standardized unitless rating (SUR) method on textile industry

    Science.gov (United States)

    Erfaisalsyah, M. H.; Mansur, A.; Khasanah, A. U.

    2017-11-01

    For a company which engaged in the textile field, specify the supplier of raw materials for production is one important part of supply chain management which can affect the company's business processes. This study aims to identify the best suppliers of raw material suppliers of yarn for PC. PKBI based on several criteria. In this study, the integration between the Analytical Hierarchy Process (AHP) and the Standardized Unitless Rating (SUR) are used to assess the performance of the suppliers. By using AHP, it can be known the value of the relative weighting of each criterion. While SUR shows the sequence performance value of the supplier. The result of supplier ranking calculation can be used to know the strengths and weaknesses of each supplier based on its performance criteria. From the final result, it can be known which suppliers should improve their performance in order to create long term cooperation with the company.

  20. Conductivity equations of protons transporting through 2D crystals obtained with the rate process theory and free volume concept

    Science.gov (United States)

    Hao, Tian; Xu, Yuanze; Hao, Ting

    2018-04-01

    The Eyring's rate process theory and free volume concept are employed to treat protons (or other particles) transporting through a 2D (two dimensional) crystal like graphene and hexagonal boron nitride. The protons are assumed to be activated first in order to participate conduction and the conduction rate is dependent on how much free volume available in the system. The obtained proton conductivity equations show that only the number of conduction protons, proton size and packing structure, and the energy barrier associated with 2D crystals are critical; the quantization conductance is unexpectedly predicted with a simple Arrhenius type temperature dependence. The predictions agree well with experimental observations and clear out many puzzles like much smaller energy barrier determined from experiments than from the density function calculations and isotope separation rate independent of the energy barrier of 2D crystals, etc. Our work may deepen our understandings on how protons transport through a membrane and has direct implications on hydrogen related technology and proton involved bioprocesses.

  1. The Rate and Process of Mangrove Forest Expansion on Above and Below Ground Carbon Relations in Coastal Louisiana

    Science.gov (United States)

    Doyle, T. W.; Pham, T. H.; Reyes, M. R.; Meriwether, J. R.

    2016-02-01

    Recent field studies have documented measureable mangrove expansion landward in tropical zones and poleward in temperate saltmarsh around the northern Gulf of Mexico. Louisiana, in particular, has been recolonized by black mangrove, Avicennia germinans, over a large spatial extent since complete dieback from freeze dating back two decades. Study sites were established near Fourchon, Louisiana to account for the rate and process of marsh/mangrove dominance on carbon burial and elevation change over the past 50 years. Transects were oriented perpendicular from waterway berm of tall and scrub mangrove cover on higher ground grading to low marsh settings of saltmarsh and mixed mangrove ingrowth. Elevation mapping, plant cover and biomass sampling, and soil core dating were conducted to evaluate carbon relations above and below ground. Results showed that sites with tall mangrove have significantly higher above ground biomass than Spartina marsh and mixed marsh/mangrove zone. AG biomass was positively correlated with soil surface elevation and negatively with tidal flood frequency. In addition, tall mangrove zones recorded a twofold increase in soil accretion and carbon burial rates compared with saltmarsh soils based on 137Cs dating. These findings support a positive feedback of mangrove ingrowth and persistence on carbon production and burial allowing higher accretion rates and elevation gains when favored by warmer climate periods lacking or following episodic freeze events.

  2. The valuation of equity warrants under the fractional Vasicek process of the short-term interest rate

    Science.gov (United States)

    Xiao, Weilin; Zhang, Weiguo; Zhang, Xili; Chen, Xiaoyan

    2014-01-01

    Motivated by the empirical evidence of long range dependence in short-term interest rates and considering the long maturities of equity warrants, we propose the fractional Vasicek model to describe the dynamics of the short rate in the pricing environment of equity warrants. Using the partial differential equation approach, we present a valuation model for equity warrants under the assumption that the short rate follows the fractional Vasicek process. After identifying the pricing model for equity warrants, we provide the parameter estimation procedure for the proposed pricing model. Since obtaining the values of equity warrants from the proposed model needs to solve a nonlinear equation, we employ a hybrid intelligent algorithm to get around this optimization problem. Furthermore, to illustrate the practicality of our proposed model, we conduct an empirical study to ascertain the performance of our proposed model using the data from China’s warrant market and the China Foreign Exchange Trade System. The comparison of traditional models (such as the Black-Scholes model, the Noreen-Wolfson model, the Lauterbach-Schultz model, and the Ukhov model) with our proposed model is also presented. The empirical results show that the mean absolute percentage error of our pricing model is 10.30%. By contrast, the Black-Scholes model, the Noreen-Wolfson model, the Lauterbach-Schultz model, and the Ukhov model applied to the same warrant produce mean absolute errors of 35.26%, 37.67%, 33.40%, 32.81%, respectively. Thus the long memory property in stochastic interest rates cannot be ignored in determining the valuation of equity warrants.

  3. The pre-rRNA processing factor DEF is rate limiting for the pathogenesis of MYCN-driven neuroblastoma.

    Science.gov (United States)

    Tao, T; Sondalle, S B; Shi, H; Zhu, S; Perez-Atayde, A R; Peng, J; Baserga, S J; Look, A T

    2017-07-06

    The nucleolar factor, digestive organ expansion factor (DEF), has a key role in ribosome biogenesis, functioning in pre-ribosomal RNA (pre-rRNA) processing as a component of the small ribosomal subunit (SSU) processome. Here we show that the peripheral sympathetic nervous system (PSNS) is very underdeveloped in def-deficient zebrafish, and that def haploinsufficiency significantly decreases disease penetrance and tumor growth rate in a MYCN-driven transgenic zebrafish model of neuroblastoma that arises in the PSNS. Consistent with these findings, DEF is highly expressed in human neuroblastoma, and its depletion in human neuroblastoma cell lines induces apoptosis. Interestingly, overexpression of MYCN in zebrafish and in human neuroblastoma cells results in the appearance of intermediate pre-rRNAs species that reflect the processing of pre-rRNAs through Pathway 2, a pathway that processes pre-rRNAs in a different temporal order than the more often used Pathway 1. Our results indicate that DEF and possibly other components of the SSU processome provide a novel site of vulnerability in neuroblastoma cells that could be exploited for targeted therapy.

  4. Acceleration and sensitivity analysis of lattice kinetic Monte Carlo simulations using parallel processing and rate constant rescaling.

    Science.gov (United States)

    Núñez, M; Robie, T; Vlachos, D G

    2017-10-28

    Kinetic Monte Carlo (KMC) simulation provides insights into catalytic reactions unobtainable with either experiments or mean-field microkinetic models. Sensitivity analysis of KMC models assesses the robustness of the predictions to parametric perturbations and identifies rate determining steps in a chemical reaction network. Stiffness in the chemical reaction network, a ubiquitous feature, demands lengthy run times for KMC models and renders efficient sensitivity analysis based on the likelihood ratio method unusable. We address the challenge of efficiently conducting KMC simulations and performing accurate sensitivity analysis in systems with unknown time scales by employing two acceleration techniques: rate constant rescaling and parallel processing. We develop statistical criteria that ensure sufficient sampling of non-equilibrium steady state conditions. Our approach provides the twofold benefit of accelerating the simulation itself and enabling likelihood ratio sensitivity analysis, which provides further speedup relative to finite difference sensitivity analysis. As a result, the likelihood ratio method can be applied to real chemistry. We apply our methodology to the water-gas shift reaction on Pt(111).

  5. Acceleration and sensitivity analysis of lattice kinetic Monte Carlo simulations using parallel processing and rate constant rescaling

    Science.gov (United States)

    Núñez, M.; Robie, T.; Vlachos, D. G.

    2017-10-01

    Kinetic Monte Carlo (KMC) simulation provides insights into catalytic reactions unobtainable with either experiments or mean-field microkinetic models. Sensitivity analysis of KMC models assesses the robustness of the predictions to parametric perturbations and identifies rate determining steps in a chemical reaction network. Stiffness in the chemical reaction network, a ubiquitous feature, demands lengthy run times for KMC models and renders efficient sensitivity analysis based on the likelihood ratio method unusable. We address the challenge of efficiently conducting KMC simulations and performing accurate sensitivity analysis in systems with unknown time scales by employing two acceleration techniques: rate constant rescaling and parallel processing. We develop statistical criteria that ensure sufficient sampling of non-equilibrium steady state conditions. Our approach provides the twofold benefit of accelerating the simulation itself and enabling likelihood ratio sensitivity analysis, which provides further speedup relative to finite difference sensitivity analysis. As a result, the likelihood ratio method can be applied to real chemistry. We apply our methodology to the water-gas shift reaction on Pt(111).

  6. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    KAUST Repository

    Moia, Davide

    2017-11-28

    We report a neutral salt water based battery which uses p-type and n-type solution processed polymer films as the cathode and the anode of the cell. The specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via formation of bipolarons in both the p-type and n-type polymers. By engineering ethylene glycol and zwitterion based side chains attached to the polymer backbone we facilitate rapid ion transport through the non-porous polymer films. This, combined with efficient transport of electronic charge via the conjugated polymer backbones, allowed the films to maintain constant capacity at high charge and discharge rates (>1000 C-rate). The electrodes also show good stability during electrochemical cycling (less than 30% decrease in capacity over >1000 cycles) and an output voltage up to 1.4 V. The performance of these semiconducting polymers with polar side-chains demonstrates the potential of this material class for fast-charging, water based electrochemical energy storage devices.

  7. Neural correlates of heart rate variability in PTSD during sub- and supraliminal processing of trauma-related cues.

    Science.gov (United States)

    Rabellino, Daniela; D'Andrea, Wendy; Siegle, Greg; Frewen, Paul A; Minshew, Reese; Densmore, Maria; Neufeld, Richard W; Théberge, Jean; McKinnon, Margaret C; Lanius, Ruth A

    2017-10-01

    Posttraumatic stress disorder (PTSD) is characterized by dysregulated arousal and altered cardiac autonomic response as evidenced by decreased high-frequency heart rate variability (HF-HRV), an indirect measure of parasympathetic modulation of the heart. Indeed, subtle threatening cues can cause autonomic dysregulation, even without explicit awareness of the triggering stimulus. Accordingly, examining the neural underpinnings associated with HF-HRV during both sub- and supraliminal exposure to trauma-related cues is critical to an enhanced understanding of autonomic nervous system dysfunction in PTSD. We compared neural activity in brain regions associated with HF-HRV in PTSD (n = 18) and healthy controls (n = 18) during exposure to sub- and supraliminal processing of personalized trauma-related words. As compared to controls, PTSD exhibited decreased HF-HRV reactivity in response to sub- and supraliminal cues. Notably, during subliminal processing of trauma-related versus neutral words, as compared to controls, PTSD showed decreased neural response associated with HF-HRV within the left dorsal anterior insula. By contrast, during supraliminal processing of trauma-related versus neutral words, decreased neural activity associated with HF-HRV within the posterior insula/superior temporal cortex, and increased neural activity associated with HF-HRV within the left centromedial amygdala was observed in PTSD as compared to controls. Impaired parasympathetic modulation of autonomic arousal in PTSD appears related to altered activation of cortical and subcortical regions involved in the central autonomic network. Interestingly, both sub- and supraliminal trauma-related cues appear to elicit dysregulated arousal and may contribute to the maintenance of hyperarousal in PTSD. Hum Brain Mapp 38:4898-4907, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. Net Reaction Rate and Neutrino Cooling Rate for the Urca Process in Departure from Chemical Equilibrium in the Crust of Fast-accreting Neutron Stars

    Science.gov (United States)

    Wang, Wei-Hua; Huang, Xi; Zheng, Xiao-Ping

    We discuss the effect of compression on Urca shells in the ocean and crust of accreting neutron stars, especially in superbursting sources. We find that Urca shells may be deviated from chemical equilibrium in neutron stars which accrete at several tenths of the local Eddington accretion rate. The deviation depends on the energy threshold of the parent and daughter nuclei, the transition strength, the temperature, and the local accretion rate. In a typical crust model of accreting neutron stars, the chemical departures range from a few tenths of kBT to tens of kBT for various Urca pairs. If the Urca shell can exist in crusts of accreting neutron stars, compression may enhance the net neutrino cooling rate by a factor of about 1-2 relative to the neutrino emissivity in chemical equilibrium. For some cases, such as Urca pairs with small energy thresholds and/or weak transition strength, the large chemical departure may result in net heating rather than cooling, although the released heat can be small. Strong Urca pairs in the deep crust are hard to be deviated even in neutron stars accreting at the local Eddington accretion rate.

  9. High-rate production of micro- and nanostructured surfaces: Injection molding and novel process for metal tooling manufacturing

    Science.gov (United States)

    De Jesus Vega, Marisely

    rapidly processed via liquid injection molding. LSR with its excellent mechanical properties, transparency, non-toxicity and rapid molding capabilities can bring the production of micro and nanostructured surfaces from laboratory research facilities to high-rate manufacturing. However, previous research on microstructured surfaces made off LSR does not focus on the processing aspect of this material. Therefore, there is a lack of understanding of how different processing conditions affect the replication of microstructures. Additionally, there are no reports molding nanostructures of LSR. Features between 115 microm and 0.250 microm were molded in this work and the effect of different processing conditions and features sizes were studied. For the last part of this work, a novel metal additive manufacturing technique was used for the production of microstructured surfaces to be used as tooling for injection molding. The printing method consists of metal pastes printed through a tip onto a steel substrate. Prior work has shown spreading and swelling of features when metal pastes extrude out of the printing tip. PDMS was studied as a binder material to minimize spreading and swelling of the features by curing right after printing. In addition, prior work has shown durability of this metal printed tool up to 5000 injection molding cycles. This work compares this durability to durability of commercially available selective laser sintering metal tools. Furthermore, surface roughness was studied as this is one of the most important things to consider when molding microchannels for certain applications.

  10. Reduced water vapor transmission rates of low-temperature solution-processed metal oxide barrier films via ultraviolet annealing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seonuk; Jeong, Yong Jin; Baek, Yonghwa; Kim, Lae Ho; Jang, Jin Hyuk; Kim, Yebyeol [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); An, Tae Kyu [Department of Polymer Science & Engineering, Korea National University of Transportation, 50 Daehak-Ro, Chungju (Korea, Republic of); Nam, Sooji, E-mail: sjnam15@etri.re.kr [Information Control Device Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700 (Korea, Republic of); Kim, Se Hyun, E-mail: shkim97@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, North Gyeongsang 712-749 (Korea, Republic of); Jang, Jaeyoung, E-mail: jyjang15@hanyang.ac.kr [Department of Energy Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Chan Eon, E-mail: cep@postech.ac.kr [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2017-08-31

    Highlights: • Sol-gel-derived aluminum oxide thin films were prepared using ultraviolet (UV) annealing. • UV irradiation dramatically promoted the densification of AlO{sub x} during the annealing stage, thereby forming a close-packed AlO{sub x} film. • The resulting AlO{sub x} films deposited on polymer substrates exhibited good water vapor blocking properties with low water vapor transmission rates (WVTRs). - Abstract: Here, we report the fabrication of low-temperature sol-gel-derived aluminum oxide (AlO{sub x}) films via ultraviolet (UV) annealing and the investigation of their water vapor blocking properties by measuring the water vapor transmission rates (WVTRs). The UV annealing process induced the formation of a dense metal-oxygen-metal bond (Al-O-Al structure) at low temperatures (<200 °C) that are compatible with commercial plastic substrates. The density of the UV-annealed AlO{sub x} thin film at 180 °C was comparable to that of AlO{sub x} thin films that have been thermally annealed at 350 °C. Furthermore, the UV-annealed AlO{sub x} thin films exhibited a high optical transparency in the visible region (>99%) and good electrical insulating properties (∼10{sup −7} A/cm{sup 2} at 2 MV/cm). Finally, we confirmed that a dense AlO{sub x} thin film was successfully deposited onto the plastic substrate via UV annealing at low temperatures, leading to a substantial reduction in the WVTRs. The Ca corrosion test was used to measure the WVTRs of AlO{sub x} thin films deposited onto polyethylene naphthalate or polyimide substrates, determined to be 0.0095 g m{sup −2} day{sup −1} (25 °C, 50% relative humidity) and 0.26 g m{sup −2} day{sup −1}, respectively.

  11. A Day in the Life of the Suwannee River: Lagrangian Sampling of Process Rates Along the River Continuum

    Science.gov (United States)

    Cohen, M. J.; Hensley, R. T.; Spangler, M.; Gooseff, M. N.

    2017-12-01

    A key organizing idea in stream ecology is the river continuum concept (RCC) which makes testable predictions about network-scale variation in metabolic and community attributes. Using high resolution (ca. 0.1 Hz) Lagrangian sampling of a wide suite of solutes - including nitrate, fDOM, dissolved oyxgen and specific conductance, we sampled the river continuum from headwaters to the sea in the Suwannee River (Florida, USA). We specifically sought to test two predictions that follow from the RCC: first, that changes in metabolism and hydraulics lead to progressive reduction in total N retention but greater diel variation with increasing stream order; and second, that variation in metabolic and nutrient processing rates is larger across stream orders than between low order streams. In addition to providing a novel test of theory, these measurements enabled new insights into the evolution of water quality through a complex landscape, in part because main-stem profiles were obtained for both high and historically low flow conditions. We observed strong evidence of metabolism and nutrient retention at low flow. Both the rate of uptake velocity and the mass retention per unit area declined with increasing stream order, and declined dramatically at high flow. Clear evidence for time varying retention (i.e., diel variation) was observed at low flow, but was masked or absent at high flow. In this geologically complex river - with alluvial, spring-fed, and blackwater headwater streams - variation across low-order streams was large, suggesting the presence of many river continuua across the network. This application of longitudinal sampling and inference underscores the utility of changing reference frames to draw new insights, but also highlights some of the challenges that need to be considered and, where possible, controlled.

  12. Effect of flaxseed supplementation rate and processing on the production, fatty acid profile, and texture of milk, butter, and cheese.

    Science.gov (United States)

    Oeffner, S P; Qu, Y; Just, J; Quezada, N; Ramsing, E; Keller, M; Cherian, G; Goddick, L; Bobe, G

    2013-02-01

    Health and nutrition professionals advise consumers to limit consumption of saturated fatty acids and increase the consumption of foods rich in n-3 fatty acids. Researchers have previously reported that feeding extruded flaxseed, which is high in C18:3n-3, improves the fatty acid profile of milk and dairy products to less saturated fatty acids and to more C18:3n-3. Fat concentrations in milk and butter decreased when cows were fed higher concentrations of extruded flaxseed. The objective of this study was to determine the optimal rate of flaxseed supplementation for improving the fatty acid profile without decreasing production characteristics of milk and dairy products. By using a double 5 × 5 Latin square design, 10 mid- to late-lactation Holstein cows were fed extruded (0, 0.91, 1.81, and 2.72 kg/d) and ground (1.81 kg/d) flaxseed as a top dressing for 2-wk periods each. At the end of each 2-wk treatment period, milk and serum samples were taken. Milk was subsequently manufactured into butter and fresh Mozzarella cheese. Increasing supplementation rates of extruded flaxseed improved the fatty acid profile of milk, butter, and cheese gradually to less saturated and atherogenic fatty acids and to more C18:3n-3 by increasing concentrations of C18:3n-3 in serum. The less saturated fatty acid profile was associated with decreased hardness and adhesiveness of refrigerated butter, which likely cause improved spreadability. Supplementation rates of extruded flaxseed did not affect dry matter intake of the total mixed ration, milk composition, and production of milk, butter, or cheese. Flaxseed processing did not affect production, fatty acid profile of milk, or texture of butter and cheese. Feeding up to 2.72 kg/d of extruded flaxseed to mid- to late-lactation Holstein cows may improve nutritional and functional properties of milk fat without compromising production parameters. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights

  13. Enhanced electrode-reducing rate during the enrichment process in an air-cathode microbial fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Shun' ichi [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan). Bio-Medical Research Inst.; J. Craig Venter Institute, San Diego, CA (United States); Japan Society for the Promotion of Science (JSPS), Tokyo (Japan); Logan, Bruce E. [Penn State Univ., University Park, PA (United States). Dept. of Civil and Environmental Engineering; Sekiguchi, Yuji [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki (Japan). Bio-Medical Research Inst.

    2012-05-15

    The improvement in electricity generation during the enrichment process of a microbial consortium was analyzed using an air-cathode microbial fuel cell (MFC) repeatedly fed with acetate that was originally inoculated with sludge from an anaerobic digester. The anodic maximum current density produced by the anode biofilm increased from 0.12 mA/cm{sup 2} at day 28 to 1.12 mA/cm{sup 2} at day 105. However, the microbial cell density on the carbon cloth anode increased only three times throughout this same time period from 0.21 to 0.69 mg protein/cm{sup 2}, indicating that the biocatalytic activity of the consortium was also enhanced. The microbial activity was calculated to have a per biomass anode-reducing rate of 374 {mu}mol electron g protein{sup -1} min{sup -1} at day 28 and 1,002 {mu}mol electron g protein{sup -1} min{sup -1} at day 105. A bacterial community analysis of the anode biofilm revealed that the dominant phylotype, which was closely related to the known exoelectrogenic bacterium, Geobacter sulfurreducens, showed an increase in abundance from 32% to 70% of the total microbial cells. Fluorescent in situ hybridization observation also showed the increase of Geobacter-like phylotypes from 53% to 72%. These results suggest that the improvement of microbial current generation in microbial fuel cells is a function of both microbial cell growth on the electrode and changes in the bacterial community highly dominated by a known exoelectrogenic bacterium during the enrichment process. (orig.)

  14. CONVERSION OF FOREIGN COMPANIES ACCOUNTS IN THE ACCOUNT CONSOLIDATION PROCESS IN ROMANIA UNDER THE CLOSING RATE METHOD

    Directory of Open Access Journals (Sweden)

    Mariana BANUTA

    2017-12-01

    Full Text Available The article approaches a topical theme of debate both in the professional academic environment and especially in the economic practice, i.e. the manner of converting the accounts of foreign companies in the account consolidation process, in Romania. We analyse the conditions of applying the accounting regulations related to the consolidation of accounts, in Romania, focusing on the manner of converting the accounts of the foreign companies according to Order no. 1802/2014 approving the accounting regulations on individual annual financial statements and consolidated annual financial statements and to the International Financial Reporting Standards (IFRS. We focused on the presentation of the practical method of applying the conversion of the accounts of the foreign companies according to the closing rate method, because irrespective of the accounting referential applied by the parent company for consolidation, this method occurs in the pre-consolidation stage, if the group leader has affiliates abroad, and the individual financial statements of the companies in the consolidation perimeter have different disclosure currencies.

  15. Sensitivity tests on the rates of the excited states of positron decays during the rapid proton capture process of the one-zone X-ray burst model

    Science.gov (United States)

    Lau, Rita

    2018-02-01

    In this paper, we investigate the sensitivities of positron decays on a one-zone model of type-I X-ray bursts. Most existing studies have multiplied or divided entire beta decay rates (electron captures and beta decay rates) by 10. Instead of using the standard Fuller & Fowler (FFNU) rates, we used the most recently developed weak library rates [1], which include rates from Langanke et al.'s table (the LMP table) (2000) [2], Langanke et al.'s table (the LMSH table) (2003) [3], and Oda et al.'s table (1994) [4] (all shell model rates). We then compared these table rates with the old FFNU rates [5] to study differences within the final abundances. Both positron decays and electron capture rates were included in the tables. We also used pn-QRPA rates [6,7] to study the differences within the final abundances. Many of the positron rates from the nuclei's ground states and initial excited energy states along the rapid proton capture (rp) process have been measured in existing studies. However, because temperature affects the rates of excited states, these studies should have also acknowledged the half-lives of the nuclei's excited states. Thus, instead of multiplying or dividing entire rates by 10, we studied how the half-lives of sensitive nuclei in excited states affected the abundances by dividing the half-lives of the ground states by 10, which allowed us to set the half-lives of the excited states. Interestingly, we found that the peak of the final abundance shifted when we modified the rates from the excited states of the 105Sn positron decay rates. Furthermore, the abundance of 80Zr also changed due to usage of pn-QRPA rates instead of weak library rates (the shell model rates).

  16. Realization of a digital rate meter as an IIR digital filter by implementing an optimized signal processing algorithm

    Directory of Open Access Journals (Sweden)

    Šaponjić Đorđe

    2009-01-01

    Full Text Available By applying the well known dualism: mean count rate - mean time between successive pulses - the equivalence between an IIR digital filter and a preset count digital rate meter has been demonstrated. By using a bank of four second order IIR filters and an optimized automated algorithm for filter selection, a practical realization of a preset count rate meter giving good tradeoff between statistical fluctuations and speed of response, particularly at low count rates such as background monitoring, is presented. The presented solution is suitable for designing portable count rate meters. The designed prototype is capable of operating up to 3600 pulses per second with an accuracy of over 4% in steady-state and response times of 1 second for the rising edge and 2 seconds for the falling edge of the mean count rate step-change.

  17. The large deviation principle and steady-state fluctuation theorem for the entropy production rate of a stochastic process in magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yong, E-mail: 83229994@qq.com [School of Mathematics and Computing Science, Hunan University of Science and Technology, Xiangtan 411201, Hunan (China); Ge, Hao, E-mail: haoge@pku.edu.cn [Beijing International Center for Mathematical Research and Biodynamic Optical Imaging Center, Peking University, Beijing 100871 (China); Xiong, Jie, E-mail: jiexiong@umac.mo [Department of Mathematics, Faculty of Science and Technology, University of Macau, Av. Padre Tomás Pereira, Taipa Macau (China); Xu, Lihu, E-mail: lihuxu@umac.mo [Department of Mathematics, Faculty of Science and Technology, University of Macau, Av. Padre Tomás Pereira, Taipa Macau (China); UMacau Zhuhai Research Institute, Zhuhai, 519080, Canton province (China)

    2016-07-15

    Fluctuation theorem is one of the major achievements in the field of nonequilibrium statistical mechanics during the past two decades. There exist very few results for steady-state fluctuation theorem of sample entropy production rate in terms of large deviation principle for diffusion processes due to the technical difficulties. Here we give a proof for the steady-state fluctuation theorem of a diffusion process in magnetic fields, with explicit expressions of the free energy function and rate function. The proof is based on the Karhunen-Loève expansion of complex-valued Ornstein-Uhlenbeck process.

  18. The use of think-aloud protocols to identify a decision-making process of community pharmacists aimed at improving CMS Star Ratings scores.

    Science.gov (United States)

    George, David L; Smith, Michael J; Draugalis, JoLaine R; Tolma, Eleni L; Keast, Shellie L; Wilson, Justin B

    2018-03-01

    The Center for Medicare and Medicaid Services (CMS) created the Star Rating system based on multiple measures that indicate the overall quality of health plans. Community pharmacists can impact certain Star Ratings measure scores through medication adherence and patient safety interventions. To explore methods, needs, and workflow issues of community pharmacists to improve CMS Star Ratings measures. Think-aloud protocols (TAPs) were conducted with active community retail pharmacists in Oklahoma. Each TAP was audio recorded and transcribed to documents for analysis. Analysts agreed on common themes, illuminated differences in findings, and saturation of the data gathered. Methods, needs, and workflow themes of community pharmacists associated with improving Star Ratings measures were compiled and organized to exhibit a decision-making process. Five TAPs were performed among three independent pharmacy owners, one multi-store owner, and one chain-store administrator. A thematically common 4-step process to monitor and improve CMS Star Ratings scores among participants was identified. To improve Star Ratings measures, pharmacists: 1) used technology to access scores, 2) analyzed data to strategically set goals, 3) assessed individual patient information for comprehensive assessment, and 4) decided on interventions to best impact Star Ratings scores. Participants also shared common needs, workflow issues, and benefits associated with methods used in improving Star Ratings. TAPs were useful in exploring processes of pharmacists who improve CMS Star Ratings scores. Pharmacists demonstrated and verbalized their methods, workflow issues, needs, and benefits related to performing the task. The themes and decision-making process identified to improving CMS Star Ratings scores will assist in the development of training and education programs for pharmacists in the community setting. Published by Elsevier Inc.

  19. Multi-rate Poisson tree processes for single-locus species delimitation under maximum likelihood and Markov chain Monte Carlo.

    Science.gov (United States)

    Kapli, P; Lutteropp, S; Zhang, J; Kobert, K; Pavlidis, P; Stamatakis, A; Flouri, T

    2017-06-01

    In recent years, molecular species delimitation has become a routine approach for quantifying and classifying biodiversity. Barcoding methods are of particular importance in large-scale surveys as they promote fast species discovery and biodiversity estimates. Among those, distance-based methods are the most common choice as they scale well with large datasets; however, they are sensitive to similarity threshold parameters and they ignore evolutionary relationships. The recently introduced "Poisson Tree Processes" (PTP) method is a phylogeny-aware approach that does not rely on such thresholds. Yet, two weaknesses of PTP impact its accuracy and practicality when applied to large datasets; it does not account for divergent intraspecific variation and is slow for a large number of sequences. We introduce the multi-rate PTP (mPTP), an improved method that alleviates the theoretical and technical shortcomings of PTP. It incorporates different levels of intraspecific genetic diversity deriving from differences in either the evolutionary history or sampling of each species. Results on empirical data suggest that mPTP is superior to PTP and popular distance-based methods as it, consistently yields more accurate delimitations with respect to the taxonomy (i.e., identifies more taxonomic species, infers species numbers closer to the taxonomy). Moreover, mPTP does not require any similarity threshold as input. The novel dynamic programming algorithm attains a speedup of at least five orders of magnitude compared to PTP, allowing it to delimit species in large (meta-) barcoding data. In addition, Markov Chain Monte Carlo sampling provides a comprehensive evaluation of the inferred delimitation in just a few seconds for millions of steps, independently of tree size. mPTP is implemented in C and is available for download at http://github.com/Pas-Kapli/mptp under the GNU Affero 3 license. A web-service is available at http://mptp.h-its.org . : paschalia.kapli@h-its.org or

  20. Effect of shear rate on aggregate size and structure in the process of aggregation and at steady state

    Czech Academy of Sciences Publication Activity Database

    Bubáková, Petra; Pivokonský, Martin; Filip, Petr

    2013-01-01

    Roč. 235, February (2013), s. 540-549 ISSN 0032-5910 R&D Projects: GA ČR GAP105/11/0247 Institutional support: RVO:67985874 Keywords : aggregation * aggregate size * fractal dimension * shear rate * steady state * time evolution Subject RIV: BK - Fluid Dynamics Impact factor: 2.269, year: 2013

  1. Learning control for riser-slug elimination and production-rate optimization for an offshore oil and gas production process

    DEFF Research Database (Denmark)

    Pedersen, Simon; Løhndorf, Petar Durdevic; Yang, Zhenyu

    2014-01-01

    , (ii) maximizing the production rate at the riser of an offshore production platform, by manipulating a topside choke valve through a learning switching model-free PID controller. The results show good steady-state performance, though a long settling time due to the unknown reference for no slugging...

  2. Gene regulation of UDP-galactose synthesis and transport: Potential rate limiting processes in initiation of milk production in humans

    Science.gov (United States)

    Lactose synthesis is believed to be rate-limiting for milk production. However, understanding the molecular events controlling lactose synthesis in humans is still rudimentary. We have utilized our established model of the RNA isolated from breast milk fat globule from 7 healthy exclusively breastfe...

  3. An analytical approach to model manufacturing a drift heterobipolar transistors: On approach to optimize technological process to increase integration rate

    Science.gov (United States)

    Pankratov, E. L.; Bulaeva, E. A.

    2015-03-01

    In this paper, we introduce an approach to increase integration rate of drift heterobipolar transistors. The approach is based on manufacturing of heterostructure with spatial configuration, doping of required areas of the heterostructure by diffusion or ion implantation and optimization of annealing of dopant and/or radiation defects.

  4. Educational Attainment as Process: Using Hierarchical Discrete-Time Event History Analysis to Model Rate of Progress

    Science.gov (United States)

    Bahr, Peter Riley

    2009-01-01

    Variables that address student enrollment patterns (e.g., persistence, enrollment inconsistency, completed credit hours, course credit load, course completion rate, procrastination) constitute a longstanding fixture of analytical strategies in educational research, particularly research that focuses on explaining variation in academic outcomes.…

  5. Creating a standardized process to offer the standard of care: continuous process improvement methodology is associated with increased rates of sperm cryopreservation among adolescent and young adult males with cancer.

    Science.gov (United States)

    Shnorhavorian, Margarett; Kroon, Leah; Jeffries, Howard; Johnson, Rebecca

    2012-11-01

    There is limited literature on strategies to overcome the barriers to sperm banking among adolescent and young adult (AYA) males with cancer. By standardizing our process for offering sperm banking to AYA males before cancer treatment, we aimed to improve rates of sperm banking at our institution. Continuous process improvement is a technique that has recently been applied to improve health care delivery. We used continuous process improvement methodologies to create a standard process for fertility preservation for AYA males with cancer at our institution. We compared rates of sperm banking before and after standardization. In the 12-month period after implementation of a standardized process, 90% of patients were offered sperm banking. We demonstrated an 8-fold increase in the proportion of AYA males' sperm banking, and a 5-fold increase in the rate of sperm banking at our institution. Implementation of a standardized process for sperm banking for AYA males with cancer was associated with increased rates of sperm banking at our institution. This study supports the role of standardized health care in decreasing barriers to sperm banking.

  6. An investigation of mechanical properties and material removal rate, tool wear rate in EDM machining process of AL2618 alloy reinforced with Si{sub 3}N{sub 4}, AlN and ZrB{sub 2} composites

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N. Mathan, E-mail: mathannagarajbe@gmail.com [Department of Mechanical Engineering and Mining Machinery Engineering, Indian Institute of Technology (ISM), Dhanbad 826004, Jharkhand (India); Kumaran, S. Senthil, E-mail: sskumaran@ymail.com [Department of Mechanical Engineering, RVS Educational Trust' s Group of Institutions, RVS School of Engineering and Technology, Dindigul 624005, Tamilnadu (India); Kumaraswamidhas, L.A., E-mail: lakdhas1978@gmail.com [Department of Mechanical Engineering and Mining Machinery Engineering, Indian Institute of Technology (ISM), Dhanbad 826004, Jharkhand (India)

    2015-11-25

    It is submitted that new approach is tried to find out what would be the outcome if Aluminum 2618 reinforced by AlN (Aluminum Nitride), Si{sub 3}N{sub 4} (Silicon Nitride) & ZrB{sub 2}(Zirconium Boride) particles were fabricated in Wt % (x = 0,2,4,6,8) by stir casting method. If the wt% is increased, the mechanical properties of the composite will proportionally increase. There will be no other promising technique than Electrical Discharge Machining (EDM) for machining metal matrix composites when they were conducted on the Aluminum 2618 composite work piece using a copper electrode in an EDM machining. It becomes very vital in the field machines and mechanism to find out Current(I), Pulse on time(T{sub ON}), Pulse off time (T{sub OFF}) on Metal Removal Rate (MRR),Tool Wear Rate(TWR) on the machining of hybrid Al2618 metal matrix composites. Taghuchi's design of experiment was used to analyse the machining characteristics of hybrid composites. To effect the parameters like current (I), Pulse on time(T{sub ON}), Pulse off time (T{sub OFF}) has been chosen as the input parameters of this work. Machining results go to show that Al2618 composites have improved mechanical properties and as a result of Material Removal Rate (MRR) and Tool Wear Rate (TWR) are reduced. Hence ANOVA (Analysis of Variance) and signal to Noise ratio are used to determine the influence of input parameters on the Material Removal Rate and Tool Wear Rate (TWR). - Highlights: • Increasing mechanical properties with addition of reinforcements. • EDM machining on AL2618 alloy reinforced with Si{sub 3}N{sub 4}, AlN and ZrB{sub 2} composites in insitu-composites. • To find out the best process parameters using Taguchi and ANOVA method. • Material removal rate (MRR) and tool wear rate (TWR) are minimized. • Composite is the best process parameter on influencing material removal rate (MRR) and tool wear rate (TWR) and depth.

  7. Processes and rates of sediment and wood accumulation in the headwater streams of the Oregon Coast Range, U.S.A.

    Science.gov (United States)

    C. L. May; R. E. Gresswell

    2003-01-01

    Abstract - Channels that have been scoured to bedrock by debris flows provide unique opportunities to calculate the rate of sediment and wood accumulation in low-order streams, to understand the temporal succession of channel morphology following disturbance, and to make inferences about processes associated with input and transport of sediment. Dendrochronology was...

  8. Analytical Hierarchy Process (Ahp) Approach on Consumer Decision Making to Stay in Star Rating Hotel in Manado City

    OpenAIRE

    Lapian, S.L.H.V. Joyce; Mokodaser, Andreas

    2015-01-01

    Hotel has became the new business that developing quickly in Manado. It is happened due to the Manado tourism city program established by the city government which indirectly opening up the opportunities for the growth of hospitality industry in Manado. The purpose of this study is to analyze the criteria hotel that influence consumer and analyze the most star rating hotel chosen by the people. This research held from May until June 2015 in Manado city. The respondent are 30 person with using...

  9. Growing Chlorella vulgaris in Photobioreactor by Continuous Process Using Concentrated Desalination: Effect of Dilution Rate on Biochemical Composition

    Directory of Open Access Journals (Sweden)

    Ângelo Paggi Matos

    2014-01-01

    Full Text Available Desalination wastewater, which contains large amount of salt waste, might lead to severely environmental pollution. This study evaluated the effect of dilution rate (0.1≤D≤0.3 day−1 on microalgal biomass productivity, lipid content, and fatty acid profile under steady-state condition of Chlorella vulgaris supplemented with concentrated desalination. Continuous culture was conducted for 55 days. Results show that the biomass productivity (Px varied from 57 to 126 mg L−1 d−1 (dry mass when the dilution rate ranged from 0.1 to 0.3 day−1. At lowest dilution rate (D=0.1 day−1, the continuous culture regime ensured the highest values of maximum biomass concentration (Xm=570±20 mL−1 and protein content (52%. Biomass lipid content was an increasing function of D. The most abundant fatty acids were the palmitic (25.3±0.6% at D=0.1 day−1 and the gamma-linolenic acid (23.5±0.1% at D=0.3 day−1 ones. These fatty acids present 14 to 18 carbons in the carbon chain, being mainly saturated and polyunsaturated, respectively. Overall, the results show that continuous culture is a powerful tool to investigate the cell growth kinetics and physiological behaviors of the algae growing on desalination wastewater.

  10. 26 Tbit s-1 line-rate super-channel transmission utilizing all-optical fast Fourier transform processing

    Science.gov (United States)

    Hillerkuss, D.; Schmogrow, R.; Schellinger, T.; Jordan, M.; Winter, M.; Huber, G.; Vallaitis, T.; Bonk, R.; Kleinow, P.; Frey, F.; Roeger, M.; Koenig, S.; Ludwig, A.; Marculescu, A.; Li, J.; Hoh, M.; Dreschmann, M.; Meyer, J.; Ben Ezra, S.; Narkiss, N.; Nebendahl, B.; Parmigiani, F.; Petropoulos, P.; Resan, B.; Oehler, A.; Weingarten, K.; Ellermeyer, T.; Lutz, J.; Moeller, M.; Huebner, M.; Becker, J.; Koos, C.; Freude, W.; Leuthold, J.

    2011-06-01

    Optical transmission systems with terabit per second (Tbit s-1) single-channel line rates no longer seem to be too far-fetched. New services such as cloud computing, three-dimensional high-definition television and virtual-reality applications require unprecedented optical channel bandwidths. These high-capacity optical channels, however, are fed from lower-bitrate signals. The question then is whether the lower-bitrate tributary information can viably, energy-efficiently and effortlessly be encoded to and extracted from terabit per second data streams. We demonstrate an optical fast Fourier transform scheme that provides the necessary computing power to encode lower-bitrate tributaries into 10.8 and 26.0 Tbit s-1 line-rate orthogonal frequency-division multiplexing (OFDM) data streams and to decode them from fibre-transmitted OFDM data streams. Experiments show the feasibility and ease of handling terabit per second data with low energy consumption. To the best of our knowledge, this is the largest line rate ever encoded onto a single light source.

  11. Seasonal variation in denitrification and dissimilatory nitrate reduction to ammonia process rates and corresponding key functional genes along an estuarine nitrate gradient

    Science.gov (United States)

    Smith, Cindy J.; Dong, Liang F.; Wilson, John; Stott, Andrew; Osborn, A. Mark; Nedwell, David B.

    2015-01-01

    This research investigated spatial-temporal variation in benthic bacterial community structure, rates of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) processes and abundances of corresponding genes and transcripts at three sites—the estuary-head, mid-estuary and the estuary mouth (EM) along the nitrate gradient of the Colne estuary over an annual cycle. Denitrification rates declined down the estuary, while DNRA rates were higher at the estuary head and middle than the EM. In four out of the six 2-monthly time-points, rates of DNRA were greater than denitrification at each site. Abundance of gene markers for nitrate-reduction (nitrate reductase narG and napA), denitrification (nitrite reductase nirS) and DNRA (DNRA nitrite reductase nrfA) declined along the estuary with significant relationships between denitrification and nirS abundance, and DNRA and nrfA abundance. Spatially, rates of denitrification, DNRA and corresponding functional gene abundances decreased along the estuary. However, temporal correlations between rate processes and functional gene and transcript abundances were not observed. PMID:26082763

  12. An experimental and analytical investigation into the effects of process vibrations on material removal rates during polishing

    Science.gov (United States)

    Mullany, B.; Mainuddin, M.; Williams, W.; Keanini, R.

    2013-06-01

    Experimental testing, using both commercially available polishing machines and a specially built test platform, demonstrates that material removal rates (MRRs) observed during polishing of fused silica are strongly affected by nanometer-scale vibration amplitudes. Specifically, a nanometer level increase in system vibrations can produce MRRs approximately 150% higher than on an inherently smoother running machine. Moreover the higher spatial frequency surface roughness values are little-effected by the spectral content of the polishing machine. Polishing under controlled conditions, using the test platform, shows that for vibration amplitudes, A ≲ 1.6 μm, and over a fairly wide range of vibration frequencies, MRR increases almost linearly with increasing input power. By contrast, for A ≳ 10 μm, MRR exhibits a rapid decay with increasing A. Order of magnitude analyses and physical arguments are presented in order to explain the qualitatively distinct MRR trends observed. In the small-amplitude limit, A ≲ 1.6 μm, two arguments are presented which suggest that the total observed removal rate, MRRtot, reflects the superposed action of chemical-mechanical removal, MRRcm, and vibration-driven, flow-induced removal, MRRflow, i.e., MRRtot=MRRcm+MRRflow. The analyses further indicate that MRRflow primarily reflects cyclic viscous shears and pressure gradients extant within the thin, non-Newtonian slurry film that exists between the polishing tool and workpiece. Shears and pressure gradients, and corresponding flow-induced MRRs, are, in turn, found to scale as √A /do ω, where A is the vibration amplitude, do is the characteristic gap thickness between the tool and workpiece, and ω is the vibration frequency. In the large-amplitude limit, A ≳ 5 μm, experimental measurements and a simple scaling argument show that the polishing slurry film becomes thick enough that the workpiece and polishing tool lose direct contact. In this limit, observed MRRs thus reflect

  13. Effect of Humidity of Poly-Cereal Flour Mixture and Screw Rotation Rate on Efficiency of Extrusion Process

    Science.gov (United States)

    Ospanov, ?bdymanap ?.; Muslimov, Nurzhan Zh.; Timurbekova, ?igul ?.; Jumabekova, Gulnar? B.

    2016-01-01

    The food industry is an important constituent of a country's economy, which provides the population with food. The development of the food industry and the supply of food products to the entire population requires improving food-manufacturing technologies, such as the process for production of extruded poly-cereal food products using…

  14. Evaluating Opportunities for Improved Processes and Flow Rates in Royal Saudi Air Force F-15 Reparable Items Supply Chain

    Science.gov (United States)

    2015-09-15

    the process (Anupindi et al, 2011). 27 How Does Lean Relate to Government? Lean started in the manufacturing sector to improve productivity...selected techniques are supply chain mapping, the lean management approach, and gap analysis. The research suggests that these techniques can improve F-15...14 Lean

  15. The astrophysical r-process and its dependence on properties of nuclei far from stability: Beta strength functions and neutron capture rates

    International Nuclear Information System (INIS)

    Klapdor, H.V.; Metzinger, J.; Oda, T.; Thielemann, F.K.; Hillebrandt, W.

    1981-01-01

    The question of the astrophysical site of the rapid neutron capture (r-) process which is believed to be responsible for the production of the heavy elements in the universe has been a problem in astrophysics for more than two decades. The solution of this problem is not only dependent on the development of realistic astrophysical supernova models, i.e. correct treatment of the hydrodynamics of gravitational collapse and supernova explosion and the equation of state of hot and dense matter, but is shown in this paper to be very sensitive also to 'standard' nuclear physics properties of nuclei far from stability such as beta decay properties and neutron capture rates. For both of the latter, strongly oversimplifying assumptions, not applying the development in nuclear physics during the last decade, have been made in almost all r-process calculations performed up to now. A critical discussion of the state of the art of such calculations seems therefore to be indicated. In this paper procedures are described which allow one to obtain: 1) β-decay properties (decay rates, β-delayed neutron emissions and fission rates); 2) neutron capture rates for neutron-rich nuclei considerably improved over what has been used up to now. The beta strength functions are calculated for approx. equal to6000 nuclei between beta stability line and neutron drip line. By hydrodynamical supernova explosion calculations using realistic stellar models it is shown that as a consequence of the improved β-rates explosive He burning is a convincing alternative site to the 'classical' r-process whose existence still is questionable. The new β-rates will be important also for the investigation of further astrophysical sites producing heavy elements such as the r(n)-processes in explosive C or Ne burning. (orig.)

  16. Slow Off-rates and Strong Product Binding Are Required for Processivity and Efficient Degradation of Recalcitrant Chitin by Family 18 Chitinases*

    Science.gov (United States)

    Kurašin, Mihhail; Kuusk, Silja; Kuusk, Piret; Sørlie, Morten; Väljamäe, Priit

    2015-01-01

    Processive glycoside hydrolases are the key components of enzymatic machineries that decompose recalcitrant polysaccharides, such as chitin and cellulose. The intrinsic processivity (PIntr) of cellulases has been shown to be governed by the rate constant of dissociation from polymer chain (koff). However, the reported koff values of cellulases are strongly dependent on the method used for their measurement. Here, we developed a new method for determining koff, based on measuring the exchange rate of the enzyme between a non-labeled and a 14C-labeled polymeric substrate. The method was applied to the study of the processive chitinase ChiA from Serratia marcescens. In parallel, ChiA variants with weaker binding of the N-acetylglucosamine unit either in substrate-binding site −3 (ChiA-W167A) or the product-binding site +1 (ChiA-W275A) were studied. Both ChiA variants showed increased off-rates and lower apparent processivity on α-chitin. The rate of the production of insoluble reducing groups on the reduced α-chitin was an order of magnitude higher than koff, suggesting that the enzyme can initiate several processive runs without leaving the substrate. On crystalline chitin, the general activity of the wild type enzyme was higher, and the difference was magnifying with hydrolysis time. On amorphous chitin, the variants clearly outperformed the wild type. A model is proposed whereby strong interactions with polymer in the substrate-binding sites (low off-rates) and strong binding of the product in the product-binding sites (high pushing potential) are required for the removal of obstacles, like disintegration of chitin microfibrils. PMID:26468285

  17. Slow Off-rates and Strong Product Binding Are Required for Processivity and Efficient Degradation of Recalcitrant Chitin by Family 18 Chitinases.

    Science.gov (United States)

    Kurašin, Mihhail; Kuusk, Silja; Kuusk, Piret; Sørlie, Morten; Väljamäe, Priit

    2015-11-27

    Processive glycoside hydrolases are the key components of enzymatic machineries that decompose recalcitrant polysaccharides, such as chitin and cellulose. The intrinsic processivity (P(Intr)) of cellulases has been shown to be governed by the rate constant of dissociation from polymer chain (koff). However, the reported koff values of cellulases are strongly dependent on the method used for their measurement. Here, we developed a new method for determining koff, based on measuring the exchange rate of the enzyme between a non-labeled and a (14)C-labeled polymeric substrate. The method was applied to the study of the processive chitinase ChiA from Serratia marcescens. In parallel, ChiA variants with weaker binding of the N-acetylglucosamine unit either in substrate-binding site -3 (ChiA-W167A) or the product-binding site +1 (ChiA-W275A) were studied. Both ChiA variants showed increased off-rates and lower apparent processivity on α-chitin. The rate of the production of insoluble reducing groups on the reduced α-chitin was an order of magnitude higher than koff, suggesting that the enzyme can initiate several processive runs without leaving the substrate. On crystalline chitin, the general activity of the wild type enzyme was higher, and the difference was magnifying with hydrolysis time. On amorphous chitin, the variants clearly outperformed the wild type. A model is proposed whereby strong interactions with polymer in the substrate-binding sites (low off-rates) and strong binding of the product in the product-binding sites (high pushing potential) are required for the removal of obstacles, like disintegration of chitin microfibrils. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. The rate coefficients for the processes of (n - n')-mixing in collisions of Rydberg atoms H*(n) with H(1s) atoms

    Energy Technology Data Exchange (ETDEWEB)

    Mihajlov, A A [Institute of Physics, PO Box 57, 11001 Belgrade (Serbia and Montenegro); Ignjatovic, Lj M [Institute of Physics, PO Box 57, 11001 Belgrade (Serbia and Montenegro); Djuric, Z [Silvaco Data Systems, Compass Point, St Ives PE27 5JL (United Kingdom); Ljepojevic, N N [Silvaco Data Systems, Compass Point, St Ives PE27 5JL (United Kingdom)

    2004-11-28

    This paper presents the results of semi-classical calculations of rate coefficients of (n - n')-mixing processes in collisions of Rydberg atoms H*(n) with H(1s) atoms. These processes have been modelled by the mechanism of the resonant energy exchange within the electron component of the H*(n) + H collisional system. The calculations of the rate coefficients, based on this model, were performed for the series of principal quantum numbers, n and n', and atomic, T{sub a}, and electronic, T{sub e}, temperatures. It was shown that these processes can be of significant influence on the populations of Rydberg atoms in weakly ionized plasmas (ionization degree {approx}<10{sup -4}), and therefore have to be included in appropriate models of such plasmas.

  19. The rate coefficients for the processes of (n - n')-mixing in collisions of Rydberg atoms H*(n) with H(1s) atoms

    International Nuclear Information System (INIS)

    Mihajlov, A A; Ignjatovic, Lj M; Djuric, Z; Ljepojevic, N N

    2004-01-01

    This paper presents the results of semi-classical calculations of rate coefficients of (n - n')-mixing processes in collisions of Rydberg atoms H*(n) with H(1s) atoms. These processes have been modelled by the mechanism of the resonant energy exchange within the electron component of the H*(n) + H collisional system. The calculations of the rate coefficients, based on this model, were performed for the series of principal quantum numbers, n and n', and atomic, T a , and electronic, T e , temperatures. It was shown that these processes can be of significant influence on the populations of Rydberg atoms in weakly ionized plasmas (ionization degree ∼ -4 ), and therefore have to be included in appropriate models of such plasmas

  20. Endoplasmic Reticulum-Associated rht-PA Processing in CHO Cells: Influence of Mild Hypothermia and Specific Growth Rates in Batch and Chemostat Cultures.

    Directory of Open Access Journals (Sweden)

    Mauricio Vergara

    Full Text Available Chinese hamster ovary (CHO cells are the main host for producing recombinant proteins with human therapeutic applications mainly because of their capability to perform proper folding and glycosylation processes. In addition, mild hypothermia is one of the main strategies for maximising the productivity of these systems. However, little information is available on the effect of culture temperature on the folding and degradation processes of recombinant proteins that takes place in the endoplasmic reticulum.In order to evaluate the effect of the mild hypothermia on processing/endoplasmatic reticulum-associated degradation (ERAD processes, batch cultures of CHO cells producing recombinant human tissue plasminogen activator (rht-PA were carried out at two temperatures (37°C and 33°C and treated with specific inhibitors of glycosylation and ERAD I (Ubiquitin/Proteasome system or ERAD II (Autophagosoma/Lisosomal system pathways. The effect of mild hypothermia was analysed separately from its indirect effect on specific cell growth rate. To do this, chemostat cultures were carried out at the same incubation conditions as the batch cultures, controlling cell growth at high (0.017 h-1 and low (0.012 h-1 dilution rates. For a better understanding of the investigated phenomenon, cell behaviour was also analysed using principal component analysis (PCA.Results suggest that rht-PA is susceptible to degradation by both ERAD pathways studied, revealing that processing and/or ERAD processes are sensitive to temperature cultivation in batch culture. Moreover, by isolating the effect of culture temperature from the effect of cell growth rate verifyed by using chemostat cultures, we have found that processing and/or ERAD processes are more sensitive to reduction in specific growth rate than low temperature, and that temperature reduction may have a positive effect on protein processing. Interestingly, PCA indicated that the integrated performance displayed by CHO

  1. The application of imperialist competitive algorithm for optimization of deposition rate in submerged arc welding process using TiO{sub 2} nano particle

    Energy Technology Data Exchange (ETDEWEB)

    Ghaderi, Mohammad Reza; Eslampanah, Amirhossein; Ghaderi, Kianoosh [Islamic Azad University, Sanandaj (Iran, Islamic Republic of); Aghakhani, Masood [Razi University, Kermanshah (Iran, Islamic Republic of)

    2015-01-15

    We used a novel optimization algorithm based on the imperialist competitive algorithm (ICA) to optimize the deposition rate in the submerged arc welding (SAW) process. This algorithm offers some advantages such as simplicity, accuracy and time saving. Experiments were conducted based on a five factor, five level rotatable central composite design (RCCD) to collect welding data for deposition rate as a function of welding current, arc voltage, contact tip to plate distance, welding speed and thickness of TiO{sub 2} nanoparticles coated on the plates of mild steel. Furthermore, regression equation for deposition rate was obtained using least squares method. The regression equation as the cost function was optimized using ICA. Ultimately, the levels of input variables to achieve maximum deposition rate were obtained using ICA. Computational results indicate that the proposed algorithm is quite effective and powerful in optimizing the cost function.

  2. The effect of temperature and strain rate on elongation to failure in nanostructured Al-0.2wt% Zr alloy fabricated by ARB process

    Directory of Open Access Journals (Sweden)

    Hanieh Solouki

    2015-12-01

    Full Text Available A nano/ultra-fine grain Al-0.2wt% Zr alloy was produced by accumulated roll bonding (ARB processafter 10 cycles. The fraction of high angle grain boundaries increased from 8% to 65.4% during 10passes during ARB process. This alloy was subjected to tensile test at different temperatures (523,573and 623 K and strain rates (0.1 and 0.01 s-1. The optimum condition of temperature and strain rate of623k and 0.01s-1 was achieved for maximum elongation to failure, leading to 100% elongation,although maximum elongation was achieved at higher strain rate and maximum chosen temperature.In fracture surfaces after the test, dimples in higher temperature were deeper, bigger, and longer thanlow temperature. Because of presenting the superplasticity character at elevated temperature andhigher strain rate, there was no evidence of necking after failure.

  3. On-line monitoring and modelling based process control of high rate nitrification - lab scale experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Pirsing, A. [Technische Univ. Berlin (Germany). Inst. fuer Verfahrenstechnik; Wiesmann, U. [Technische Univ. Berlin (Germany). Inst. fuer Verfahrenstechnik; Kelterbach, G. [Technische Univ. Berlin (Germany). Inst. fuer Mess- und Regelungstechnik; Schaffranietz, U. [Technische Univ. Berlin (Germany). Inst. fuer Mess- und Regelungstechnik; Roeck, H. [Technische Univ. Berlin (Germany). Inst. fuer Mess- und Regelungstechnik; Eichner, B. [Technische Univ. Berlin (Germany). Inst. fuer Anorganische und Analytische Chemie; Szukal, S. [Technische Univ. Berlin (Germany). Inst. fuer Anorganische und Analytische Chemie; Schulze, G. [Technische Univ. Berlin (Germany). Inst. fuer Anorganische und Analytische Chemie

    1996-09-01

    This paper presents a new concept for the control of nitrification in highly polluted waste waters. The approach is based on mathematical modelling. To determine the substrate degradation rates of the microorganisms involved, a mathematical model using gas measurement is used. A fuzzy-controller maximises the capacity utilisation efficiencies. The experiments carried out in a lab-scale reactor demonstrate that even with highly varying ammonia concentrations in the influent, the nitrogen concentrations in the effluent can be kept within legal limits. (orig.). With 11 figs.

  4. Growing Chlorella vulgaris in Photobioreactor by Continuous Process Using Concentrated Desalination: Effect of Dilution Rate on Biochemical Composition

    OpenAIRE

    Matos, Ângelo Paggi; Torres, Regina Coeli de Oliveira; Morioka, Luiz Rodrigo Ito; Moecke, Elisa Helena Siegel; França, Kepler Borges; Sant’Anna, Ernani Sebastião

    2014-01-01

    Desalination wastewater, which contains large amount of salt waste, might lead to severely environmental pollution. This study evaluated the effect of dilution rate (0.1≤D≤0.3 day−1) on microalgal biomass productivity, lipid content, and fatty acid profile under steady-state condition of Chlorella vulgaris supplemented with concentrated desalination. Continuous culture was conducted for 55 days. Results show that the biomass productivity (Px) varied from 57 to 126 mg L−1 d−1 (dry mass) when t...

  5. Effect of pressure-drop rate on the isolation of cananga oil using instantaneous controlled pressure-drop process

    OpenAIRE

    Kristiawan, Magdalena; Sobolik, Vaclav; Al Haddad, Mazen; Allaf, Karim

    2008-01-01

    The isolation of Indonesian cananga oil was carried out by a new process, instantaneous controlled pressure drop (DIC). Dry cananga flowers (Cananga odorata Hook. fil. et Thomson, forma macrophylla) were exposed for a short time to saturated steam and then the pressure was abruptly decreased to a vacuum level (about 5 kPa). This abrupt pressure drop provokes auto-vaporization of the superheated volatile compounds, expansion and breaking of the cell walls and instantaneous cooling. In this ...

  6. Workflow efficiency for the treatment planning process in CT-guided high-dose-rate brachytherapy for cervical cancer.

    Science.gov (United States)

    Michaud, Anthony L; Benedict, Stanley; Montemayor, Eliseo; Hunt, Jon Paul; Wright, Cari; Mathai, Mathew; Mayadev, Jyoti S

    2016-01-01

    To investigate process efficiency, we present a prospective investigation of the treatment planning phase of image-guided brachytherapy (BT) for cervical cancer using a specific checklist. From October 2012 to January 2014, 76 BT procedures were consecutively performed. Prospective data on the CT-based treatment planning process was collected using a specific checklist which details the following steps: (1) dosimetry planning, (2) physician review start, (3) physician review time, (4) dosimetry processing, (5) physics review start, (6) physics review, and (7) procedural pause. Variables examined included the use of a pre-BT MRI, clinic duty conflicts, resident teaching, and the use of specific BT planners. Analysis was performed using descriptive statistics, t-test, and analysis of variance. Seventy-five prospectively gathered checklists comprised this analysis. The mean time for treatment planning was 95 minutes (med 94, std 18). The mean intervals in the above steps were (1) = 42, (2) = 5, (3) = 19, (4) = 10, (5) = 6, (6) = 13, and (7) = 26 minutes. There was no statistical difference in patients who had a pre-BT MRI. Resident teaching did not influence time, p = 0.17. Treatment planning time was decreased with a specific planner, p = 0.0015. A skillful team approach is required for treatment planning efficiency in image-guided BT. We have found that the specific BT planners can have a significant effect on the overall planning efficiency. We continue to examine clinical and workflow-related factors that will enhance our safety and workflow process with BT. Published by Elsevier Inc.

  7. Investigation on the Effect of Nozzle Number on the Recirculation Rate and Mixing Time in the RH Process Using VOF + DPM Model

    Science.gov (United States)

    Ling, Haitao; Li, Fei; Zhang, Lifeng; Conejo, Alberto N.

    2016-06-01

    A mathematical model has been developed to explain the effect of the number of nozzles on recirculation flow rate in the RH process. Experimental data from water modeling were employed to validate the mathematical model. The experimental data included the velocity fields measured with a particle image velocimetry technique and mixing time. The multiphase model volume of fluid was employed to allow a more realistic representation of the free surface in the vacuum chamber while injected argon bubbles were treated as discrete phase particles and modeled using the discrete phase model. Interfacial forces between bubbles and liquid phase were considered, including the lift force. The simulations carried out with the mathematical model involved changes in the gas flow rate from 12 to 36 L/min and a number of nozzles from 4 to 8. The results indicated a logarithmic increment in the recirculation rate as the gas flow rate increased and also corresponded with an exponential decrease in mixing time. The plume area and liquid velocities resulting from individual nozzles were computed. A maximum optimum recirculation rate was defined based on a mechanism proposed to explain the effect of gas flow rate and the number of nozzles on the recirculation rate.

  8. Aging kinetics of levoglucosan orientational glass as a rate dispersion process and consequences for the heterogeneous dynamics view.

    Science.gov (United States)

    Righetti, Maria Cristina; Tombari, Elpidio; Johari, G P

    2016-08-07

    Aging kinetics of a glass is currently modeled in terms of slowing of its α-relaxation dynamics, whose features are interpreted in terms of dynamic heterogeneity, i.e., formation and decay of spatially and temporally distinct nm-size regions. To test the merits of this view, we studied the calorimetric effects of aging an orientational glass of levoglucosan crystal in which such regions would not form in the same way as they form in liquids, and persist in structural glasses, because there is no liquid-like molecular diffusion in the crystal. By measuring the heat capacity, Cp, we determined the change in the enthalpy, H, and the entropy, S, during two aging-protocols: (a) keeping the samples isothermally at temperature, Ta, and measuring the changes after different aging times, ta, and (b) keeping the samples at different Tas and measuring the changes after the same ta. A model-free analysis of the data shows that as ta is increased (procedure (a)), H and S decrease according to a dispersive rate kinetics, and as Ta is increased (procedure (b)), H and S first increase, reach a local maximum at a certain Ta, and then decrease. Even though there is no translational diffusion to produce (liquid-like) free volume, and no translational-rotational decoupling, the aging features are indistinguishable from those of structural glasses. We also find that the Kohlrausch parameter, originally fitted to the glass-aging data, decreases with decrease in Ta, which is incompatible with the current use of the aging data for estimating the α-relaxation time. We argue that the vibrational state of a glass is naturally incompatible with its configurational state, and both change on aging until they are compatible, in the equilibrium liquid. So, dipolar fluctuations seen as the α-relaxation would not be the same motions that cause aging. We suggest that aging kinetics is intrinsically dispersive with its own characteristic rate constant and it does not yield the α-relaxation rate

  9. Investigation of column flotation process on sulphide ore using 2-electrode capacitance sensor: The effect of air flow rate and solid percentage

    Science.gov (United States)

    Haryono, Didied; Harjanto, Sri; Wijaya, Rifky; Oediyani, Soesaptri; Nugraha, Harisma; Huda, Mahfudz Al; Taruno, Warsito Purwo

    2018-04-01

    Investigation of column flotation process on sulphide ore using 2-electrode capacitance sensor is presented in this paper. The effect of air flow rate and solid percentage on column flotation process has been experimentally investigated. The purpose of this paper is to understand the capacitance signal characteristic affected by the air flow rate and the solid percentage which can be used to determine the metallurgical performance. Experiments were performed using a laboratory column flotation cell which has a diameter of 5 cm and the total height of 140 cm. The sintered ceramic sparger and wash water were installed at the bottom and above of the column. Two-electrode concave type capacitance sensor was also installed at a distance of 50 cm from the sparger. The sensor was attached to the outer wall of the column, connected to data acquisition system, manufactured by CTECH Labs Edwar Technology and personal computer for further data processing. Feed consisting ZnS and SiO2 with the ratio of 3:2 was mixed with some reagents to make 1 litre of slurry. The slurry was fed into the aerated column at 100 cm above the sparger with a constant rate and the capacitance signals were captured during the process. In this paper, 7.5 and 10% of solid and 2-4 L/min of air flow rate with 0.5 L/min intervals were used as independent variables. The results show that the capacitance signal characteristics between the 7.5 and 10% of solid are different at any given air flow rate in which the 10% solid produced signals higher than those of 7.5%. Metallurgical performance and capacitance signal exhibit a good correlation.

  10. Effects of pH, Temperature, Dissolved Oxygen, and Flow Rate on Phosphorus Release Processes at the Sediment and Water Interface in Storm Sewer

    Directory of Open Access Journals (Sweden)

    Haiyan Li

    2013-01-01

    Full Text Available The effects of pH, temperature, dissolved oxygen (DO, and flow rate on the phosphorus (P release processes at the sediment and water interface in rainwater pipes were investigated. The sampling was conducted in a residential storm sewer of North Li Shi Road in Xi Cheng District of Beijing on August 3, 2011. The release rate of P increased with the increase of pH from 8 to 10. High temperature is favorable for the release of P. The concentration of total phosphorus (TP in the overlying water increased as the concentration of DO decreased. With the increase of flow rate from 0.7 m s−1 to 1.1 m s−1, the concentration of TP in the overlying water increased and then tends to be stable. Among all the factors examined in the present study, the flow rate is the primary influence factor on P release. The cumulative amount of P release increased with the process of pipeline runoff in the rainfall events with high intensities and shorter durations. Feasible measures such as best management practices and low-impact development can be conducted to control the P release on urban sediments by slowing down the flow rate.

  11. Image processing techniques revealing the relationship between the field-measured ambient gamma dose equivalent rate and geological conditions at a granitic area, Velence Mountains, Hungary

    Science.gov (United States)

    Beltran Torres, Silvana; Petrik, Attila; Zsuzsanna Szabó, Katalin; Jordan, Gyozo; Szabó, Csaba

    2017-04-01

    In order to estimate the annual dose that the public receive from natural radioactivity, the identification of the potential risk areas is required which, in turn, necessitates understanding the relationship between the spatial distribution of natural radioactivity and the geogenic risk factors (e.g., rock types, dykes, faults, soil conditions, etc.). A detailed spatial analysis of ambient gamma dose equivalent rate was performed in the western side of Velence Mountains, the largest outcropped granitic area in Hungary. In order to assess the role of local geology in the spatial distribution of ambient gamma dose rates, field measurements were carried out at ground level at 300 sites along a 250 m x 250 m regular grid in a total surface of 14.7 km2. Digital image processing methods were applied to identify anomalies, heterogeneities and spatial patterns in the measured gamma dose rates, including local maxima and minima determination, digital cross sections, gradient magnitude and gradient direction, second derivative profile curvature, local variability, lineament density, 2D autocorrelation and directional variogram analyses. Statistical inference showed that different gamma dose rate levels are associated with the rock types (i.e., Carboniferous granite, Pleistocene colluvial, proluvial, deluvial sediments and talus, and Pannonian sand and pebble), with the highest level on the Carboniferous granite including outlying values. Moreover, digital image processing revealed that linear gamma dose rate spatial features are parallel to the SW-NE dyke system and possibly to the NW-SE main fractures. The results of this study underline the importance of understanding the role of geogenic risk factors influencing the ambient gamma dose rate received by public. The study also demonstrates the power of the image processing techniques for the identification of spatial pattern in field-measured geogenic radiation.

  12. Trophic position and metabolic rate predict the long-term decay process of radioactive cesium in fish: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Hideyuki Doi

    Full Text Available Understanding the long-term behavior of radionuclides in organisms is important for estimating possible associated risks to human beings and ecosystems. As radioactive cesium (¹³⁷Cs can be accumulated in organisms and has a long physical half-life, it is very important to understand its long-term decay in organisms; however, the underlying mechanisms determining the decay process are little known. We performed a meta-analysis to collect published data on the long-term ¹³⁷Cs decay process in fish species to estimate biological (metabolic rate and ecological (trophic position, habitat, and diet type influences on this process. From the linear mixed models, we found that 1 trophic position could predict the day of maximum ¹³⁷Cs activity concentration in fish; and 2 the metabolic rate of the fish species and environmental water temperature could predict ecological half-lives and decay rates for fish species. These findings revealed that ecological and biological traits are important to predict the long-term decay process of ¹³⁷Cs activity concentration in fish.

  13. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    OpenAIRE

    Moia, Davide; Giovannitti, Alexander; Szumska, Anna A.; Schnurr, Martin; Rezasoltani, Elham; Maria, Iuliana P.; Barnes, Piers R. F.; McCulloch, Iain; Nelson, Jenny

    2017-01-01

    We report a neutral salt water based battery which uses p-type and n-type solution processed polymer films as the cathode and the anode of the cell. The specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via formation of bipolarons in both the p-type and n-type polymers. By engineering ethylene glycol and zwitterion based side chains attached to the polymer backbone we facilitate rapid ion transport through the non-porous polymer films. This, combined with efficient t...

  14. Effect of different rates of spent coffee grounds (SCG) on composting process, gaseous emissions and quality of end-product.

    Science.gov (United States)

    Santos, Cátia; Fonseca, João; Aires, Alfredo; Coutinho, João; Trindade, Henrique

    2017-01-01

    The use of spent coffee grounds (SCG) in composting for organic farming is a viable way of valorising these agro-industrial residues. In the present study, four treatments with different amounts of spent coffee grounds (SCG) were established, namely, C 0 (Control), C 10 , C 20 and C 40 , containing 0, 10, 20 and 40% of SCG (DM), respectively; and their effects on the composting process and the end-product quality characteristics were evaluated. The mixtures were completed with Acacia dealbata L. shoots and wheat straw. At different time intervals during composting, carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) emissions were measured and selected physicochemical characteristics of the composts were evaluated. During the composting process, all treatments showed a substantial decrease in total phenolics and total tannins, and an important increase in gallic acid. Emissions of greenhouse gases were very low and no significant difference between the treatments was registered. The results indicated that SCG may be successfully composted in all proportions. However C 40 , was the treatment which combined better conditions of composting, lower GHG emissions and better quality of end product. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Microstructure/processing relationships in high-energy high-rate consolidated powder composites of Nb-stabilized Ti3Al+TiAl

    Energy Technology Data Exchange (ETDEWEB)

    Persad, C.; Lee, B.; Hou, C.; Eliezer, Z.; Marcus, H.L.

    1989-01-01

    A new approach to powder processing is employed in forming titanium aluminide composites. The processing consists of internal heating of a customized powder blend by a fast electrical discharge of a homopolar generator. The high-energy high-rate '1MJ in 1s' pulse permits rapid heating of an electrically conducting powder mixture in a cold wall die. This short time at temperature approach offers the opportunity to control phase transformations and the degree of microstructural coarsening not readily possible with standard powder-processing approaches. This paper describes the consolidation results of titanium aluminide-based powder-composite materials. The focus of this study was the definition of microstructure/processing relationships for each of the composite constituents, first as monoliths and then in composite forms. Non-equilibrium phases present in rapidly solidified TiAl powders are transformed to metastable intermediates en route to the equilibrium gamma phase.

  16. Model-based intensification of a fed-batch microbial process for the maximization of polyhydroxybutyrate (PHB) production rate.

    Science.gov (United States)

    Penloglou, Giannis; Vasileiadou, Athina; Chatzidoukas, Christos; Kiparissides, Costas

    2017-08-01

    An integrated metabolic-polymerization-macroscopic model, describing the microbial production of polyhydroxybutyrate (PHB) in Azohydromonas lata bacteria, was developed and validated using a comprehensive series of experimental measurements. The model accounted for biomass growth, biopolymer accumulation, carbon and nitrogen sources utilization, oxygen mass transfer and uptake rates and average molecular weights of the accumulated PHB, produced under batch and fed-batch cultivation conditions. Model predictions were in excellent agreement with experimental measurements. The validated model was subsequently utilized to calculate optimal operating conditions and feeding policies for maximizing PHB productivity for desired PHB molecular properties. More specifically, two optimal fed-batch strategies were calculated and experimentally tested: (1) a nitrogen-limited fed-batch policy and (2) a nitrogen sufficient one. The calculated optimal operating policies resulted in a maximum PHB content (94% g/g) in the cultivated bacteria and a biopolymer productivity of 4.2 g/(l h), respectively. Moreover, it was demonstrated that different PHB grades with weight average molecular weights of up to 1513 kg/mol could be produced via the optimal selection of bioprocess operating conditions.

  17. Processing of fetal heart rate through non-invasive adaptive system based on recursive least squares algorithm

    Science.gov (United States)

    Fajkus, Marcel; Nedoma, Jan; Martinek, Radek; Vasinek, Vladimir

    2017-10-01

    In this article, we describe an innovative non-invasive method of Fetal Phonocardiography (fPCG) using fiber-optic sensors and adaptive algorithm for the measurement of fetal heart rate (fHR). Conventional PCG is based on a noninvasive scanning of acoustic signals by means of a microphone placed on the thorax. As for fPCG, the microphone is placed on the maternal abdomen. Our solution is based on patent pending non-invasive scanning of acoustic signals by means of a fiber-optic interferometer. Fiber-optic sensors are resistant to technical artifacts such as electromagnetic interferences (EMI), thus they can be used in situations where it is impossible to use conventional EFM methods, e.g. during Magnetic Resonance Imaging (MRI) examination or in case of delivery in water. The adaptive evaluation system is based on Recursive least squares (RLS) algorithm. Based on real measurements provided on five volunteers with their written consent, we created a simplified dynamic signal model of a distribution of heartbeat sounds (HS) through the human body. Our created model allows us to verification of the proposed adaptive system RLS algorithm. The functionality of the proposed non-invasive adaptive system was verified by objective parameters such as Sensitivity (S+) and Signal to Noise Ratio (SNR).

  18. 57Fe Moessbauer Spectroscopy Studies of Meteorites: Implications for Weathering Rates, Meteorite Flux, and Early Solar System Processes

    International Nuclear Information System (INIS)

    Bland, P. A.; Berry, F. J.; Jull, A. J. T.; Smith, T. B.; Bevan, A. W. R.; Cadogan, J. M.; Sexton, A. S.; Franchi, L. A.; Pillinger, C. T.

    2002-01-01

    Ordinary chondrite finds, terrestrial age dated using 14 C analyses, from different meteorite accumulation sites, have been examined by Moessbauer spectroscopy to quantitatively determine terrestrial oxidation. We observe differences in weathering rates between sites, and also between different chondrite groups. A comparison of weathering over time, and its effect in 'eroding' meteorites, together with the number and mass distribution of meteorites in each region, enables us to derive estimates of the number of meteorite falls over a given mass per year. Studies of how the oxygen isotopic composition of samples varies with weathering indicate that incipient alteration may occur without a pronounced isotopic effect, possibly due to weathering of silicates to topotactically oriented smectite confined spaces where the water volume is limited. This finding has profound implications for the use of oxygen isotopes as a tool in understanding water-rock interaction. It also may reconcile previously contradictory data regarding the nebular or asteroidal location of pre-terrestrial aqueous alteration. Finally, Moessbauer spectroscopy is also found to be a useful tool in determining mineral abundance in carbonaceous chondrites, where a fine-grained matrix makes traditional approaches inapplicable. Again, the results have implications for the modification of chondritic materials in the early solar system.

  19. Effects of organic loading rates on reactor performance and microbial community changes during thermophilic aerobic digestion process of high-strength food wastewater.

    Science.gov (United States)

    Jang, Hyun Min; Lee, Jae Won; Ha, Jeong Hyub; Park, Jong Moon

    2013-11-01

    To evaluate the applicability of single-stage thermophilic aerobic digestion (TAD) process treating high-strength food wastewater (FWW), TAD process was operated at four organic loading rates (OLRs) from 9.2 to 37.2 kg COD/m(3)d. The effects of OLRs on microbial community changes were also examined. The highest volumetric removal rate (13.3 kg COD/m(3)d) and the highest thermo-stable protease activity (0.95 unit/mL) were detected at OLR=18.6 kg COD/m(3)d. Denaturing gradient gel electrophoresis (DGGE) profiles and quantitative PCR (qPCR) results showed significant microbial community shifts in response to changes in OLR. In particular, DGGE and phylogenetic analysis demonstrate that the presence of Bacillus sp. (phylum of Firmicutes) was strongly correlated with efficient removal of organic particulates from high-strength food wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Stability of Mg-sulfates at-10C and the rates of dehydration/rehydration processes under conditions relevant to Mars

    Science.gov (United States)

    Wang, A.; Freeman, J.J.; Chou, I.-Ming; Jolliff, B.L.

    2011-01-01

    We report the results of low temperature (-10??C) experiments on the stability fields and phase transition pathways of five hydrous Mg-sulfates. A low temperature form of MgSO 47H 2O (LT-7w) was found to have a wide stability field that extends to low relative humidity (???13% RH at-10??C). Using information on the timing of phase transitions, we extracted information on the reaction rates of five important dehydration and rehydration processes. We found that the temperature dependencies of rate constants for dehydration processes differ from those of rehydration, which reflect differences in reaction mechanisms. By extrapolating these rate constants versus T correlations into the T range relevant to Mars, we can evaluate the possibility of occurrence of specific processes and the presence of common Mg-sulfate species present on Mars in different periods and locations. We anticipate in a moderate obliquity period, starkeyite and LH-MgSO 4H 2O should be two common Mg-sulfates at the surface, another polymorph MH-MgSO 4H 2O can exist at the locations where hydrothermal processes may have occurred. In polar regions or within the subsurface of other regions, meridianiite (coexisting with water ice, near 100% RH) and LT-7w (over a large RH range) are the stable phases. During a high obliquity period, meridianiite and LT-7w should exhibit widespread occurrence. The correlations of reaction rates versus temperature found in this study imply that dehydration and rehydration of hydrous Mg-sulfates would always be slower than the sublimation and crystallization of water ice, which would be supported by mission observations from Odyssey and by Mars Exploration Rovers. Copyright 2011 by the American Geophysical Union.

  1. Parallel processing for a 1-D time-dependent solution to impurity rate equations for fusion plasma simulations

    International Nuclear Information System (INIS)

    Veerasingam, R.

    1990-01-01

    In fusion plasmas impurities such as carbon, oxygen or nickel can contaminate the plasma and cause degradation of the performance of a fusion device through radiation. However, impurities can also be used as diagnostics to obtain information about a plasma through spectroscopic experiments which can then be used in plasma modeling and simulations. In the past, serial algorithms have been described for either the time dependent or steady state problem. In this paper, we describe a parallel procedure adopted to solve the time-dependent problem. It can be shown that for the steady state problem a parallel procedure would not be a useful application of parallelization because a few seconds of the Central Processing Unit time on a CRAY-XMP or IBM 3090/600S would suffice to obtain the solution, while this is not the case for the time-dependent problem. In order to study the effects of low Z and high Z impurities on the final state of a plasma, time-dependent solutions are necessary. For purposes of diagnostics and comparisons with experiments, a fast turn around time of the simulations would be advantageous. We have implemented a parallel algorithm on and IBM 3090/600S and tested its performance for a typical set of fusion plasma parameters. 4 refs., 1 tab

  2. Processing of hydrocarbon-containing ices by cosmic ray analogs: Unsaturated compounds production, cross sections and desorption rates.

    Science.gov (United States)

    Pilling, Sergio; Andrade, Diana; Domaracka, Alicja; Rothard, Hermann; Boduch, Philippe; Da Silveira, Enio

    2012-07-01

    The formation of C=C and C\\equivC bonds from the processing of pure c-C_6H_{12} (cyclohexane) and mixed H_2O:NH_3:c-C_6H_{12} (1:0.3:0.7) ices by highly-charged, and energetic ions (219 MeV ^{16}O^{7+} and 632 MeV ^{58}Ni^{24+}) is studied. The experiments simulate the physical chemistry induced by medium-mass and heavy-ion cosmic rays in interstellar ices. The measurements were performed inside a high vacuum chamber at the heavy-ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France. The gas samples were deposited onto a polished CsI substrate previously cooled to 13 K. In-situ analysis was performed by a Fourier transform infrared (FTIR) spectrometry at different ion fluences. Dissociation cross section of cyclohexane and its halflife in astrophysical environments were determined. A comparison between spectra of bombarded ices and young stellar sources indicates that the initial composition of grains in theses environments should contain a mixture of H_2O, NH_3, CO (or CO_2), simple alkanes, and CH_3OH. Several species containing double or triple bounds were identified in the radiochemical products, such as hexene, cyclohexene, benzene, OCN^-, CO, CO_2, as well as several aliphatic and aromatic alkanes and alkynes. The results suggest an alternative scenario for the production of unsaturated carbon chain species (and dehydrogenation) in interstellar ices induced by cosmic ray bombardment.

  3. Biological treatment of nitrogen-rich refinery wastewater by partial nitritation (SHARON) process.

    Science.gov (United States)

    Milia, S; Cappai, G; Perra, M; Carucci, A

    2012-01-01

    Wastewater discharges containing high nitrogen levels can be toxic to aquatic life and cause eutrophication. In this study, the application of the SHARON (Single reactor for High activity Ammonium Removal Over Nitrite) process for the treatment of refinery wastewater (sour water) was evaluated, in view of its coupling with the ANAMMOX (ANaerobic AMMonium OXidation) process. A Continuous Flow Stirred Tank Reactor was initially fed with a synthetic medium, and the applied NH4-N concentration and wastewater/synthetic medium ratio were progressively increased up to 2000 mgN/L and 100%, respectively. Despite the high potential toxic effect of the real wastewater, overall SHARON performance did not decrease with the increasing real wastewater/synthetic medium ratio, and biomass showed progressive acclimation to the toxic compounds in the real wastewater, as demonstrated by toxicity assessments. NH4-N and dissolved organic carbon removal efficiency were around 50% and 65%, respectively. Moreover, the effluent was characterized by a NO2-N/NH4-N ratio of 0.9 +/- 0.01 and low nitrate concentration (<30 mgN/L), in line with the requirements for the subsequent treatment by the ANAMMOX process.

  4. Multi-GNSS high-rate RTK, PPP and novel direct phase observation processing method: application to precise dynamic displacement detection

    Science.gov (United States)

    Paziewski, Jacek; Sieradzki, Rafal; Baryla, Radoslaw

    2018-03-01

    This paper provides the methodology and performance assessment of multi-GNSS signal processing for the detection of small-scale high-rate dynamic displacements. For this purpose, we used methods of relative (RTK) and absolute positioning (PPP), and a novel direct signal processing approach. The first two methods are recognized as providing accurate information on position in many navigation and surveying applications. The latter is an innovative method for dynamic displacement determination with the use of GNSS phase signal processing. This method is based on the developed functional model with parametrized epoch-wise topocentric relative coordinates derived from filtered GNSS observations. Current regular kinematic PPP positioning, as well as medium/long range RTK, may not offer coordinate estimates with subcentimeter precision. Thus, extended processing strategies of absolute and relative GNSS positioning have been developed and applied for displacement detection. The study also aimed to comparatively analyze the developed methods as well as to analyze the impact of combined GPS and BDS processing and the dependence of the results of the relative methods on the baseline length. All the methods were implemented with in-house developed software allowing for high-rate precise GNSS positioning and signal processing. The phase and pseudorange observations collected with a rate of 50 Hz during the field test served as the experiment’s data set. The displacements at the rover station were triggered in the horizontal plane using a device which was designed and constructed to ensure a periodic motion of GNSS antenna with an amplitude of ~3 cm and a frequency of ~4.5 Hz. Finally, a medium range RTK, PPP, and direct phase observation processing method demonstrated the capability of providing reliable and consistent results with the precision of the determined dynamic displacements at the millimeter level. Specifically, the research shows that the standard deviation of

  5. Improving Prediction Accuracy of a Rate-Based Model of an MEA-Based Carbon Capture Process for Large-Scale Commercial Deployment

    Directory of Open Access Journals (Sweden)

    Xiaobo Luo

    2017-04-01

    Full Text Available Carbon capture and storage (CCS technology will play a critical role in reducing anthropogenic carbon dioxide (CO2 emission from fossil-fired power plants and other energy-intensive processes. However, the increment of energy cost caused by equipping a carbon capture process is the main barrier to its commercial deployment. To reduce the capital and operating costs of carbon capture, great efforts have been made to achieve optimal design and operation through process modeling, simulation, and optimization. Accurate models form an essential foundation for this purpose. This paper presents a study on developing a more accurate rate-based model in Aspen Plus® for the monoethanolamine (MEA-based carbon capture process by multistage model validations. The modeling framework for this process was established first. The steady-state process model was then developed and validated at three stages, which included a thermodynamic model, physical properties calculations, and a process model at the pilot plant scale, covering a wide range of pressures, temperatures, and CO2 loadings. The calculation correlations of liquid density and interfacial area were updated by coding Fortran subroutines in Aspen Plus®. The validation results show that the correlation combination for the thermodynamic model used in this study has higher accuracy than those of three other key publications and the model prediction of the process model has a good agreement with the pilot plant experimental data. A case study was carried out for carbon capture from a 250 MWe combined cycle gas turbine (CCGT power plant. Shorter packing height and lower specific duty were achieved using this accurate model.

  6. The A daptations of SMEs into Rating Process within the S cope of Bas el Arrangements a Study in the city of Corum

    Directory of Open Access Journals (Sweden)

    Recep Çakar

    2014-12-01

    Full Text Available SMEs operate in certain hardships when the developments in financial markets are taken into account. The primary of these hardships is the difficulty in reaching low-cost finance facilities which are crucial for competing and growing. When it comes to today, the most important developments affecting the SMEs in terms of finance are Basel arrangements. From now on, financial institutions will take the rating notes of SMEs into consideration while giving credits to them. Financial resources will be provided for SMEs in accordance with their rating, and therefore competition advantage and disadvantages of SMEs will be ensued.A hesitation about the orientation of SMEs to the financing technique which is brought by Basel arrangements occurred and thus a study was conducted relating to the matter in the city of Corum. When the results of the study were analysed, it was realised that the SMEs operating in Corum were not sufficiently informed about the rating system brought about Basel arrangements and also the ones who were knowledgeable about these arrangements did not demand rating due to the cost issues of this system. The first and foremost reason of adaptation problems into Basel process was the fact that the SMEs were run by the proprietors themselves not the professional managers, and there were not finance managers in those SMEs

  7. STADEERS: a software package for the statistical design of experiments pertaining to the estimation of parameters in rate expressions that describe enzyme-catalyzed processes.

    Science.gov (United States)

    Balcão, V M; Malcata, F X

    1993-12-01

    This paper describes a computational algorithm (STADEERS--STAtistical Design of Experiments in Enzyme ReactorS) for the statistical design of biochemical engineering experiments. The type of experiment that qualifies for this package involves a batch reaction catalyzed by a soluble enzyme where the activity of the enzyme decays with time. Assuming that both the catalytic action and the deactivation of the enzyme obey known rate expressions, the present code is helpful in the process of obtaining estimates of the kinetic parameters by providing as output the times at which samples should be withdrawn from the reacting mixture. Starting D-optimal design is used as a basis for the statistical approach. This BASIC code is a powerful tool when fitting a rate expression to data because it increases the effectiveness of experimentation by helping the biochemical kineticist obtain data points with the largest possible informational content.

  8. Convergent validity of the Integrated Visual and Auditory Continuous Performance Test (IVA+Plus): associations with working memory, processing speed, and behavioral ratings.

    Science.gov (United States)

    Arble, Eamonn; Kuentzel, Jeffrey; Barnett, Douglas

    2014-05-01

    Though the Integrated Visual and Auditory Continuous Performance Test (IVA + Plus) is commonly used by researchers and clinicians, few investigations have assessed its convergent and discriminant validity, especially with regard to its use with children. The present study details correlates of the IVA + Plus using measures of cognitive ability and ratings of child behavior (parent and teacher), drawing upon a sample of 90 psychoeducational evaluations. Scores from the IVA + Plus correlated significantly with the Working Memory and Processing Speed Indexes from the Fourth Edition of the Wechsler Intelligence Scales for Children (WISC-IV), though fewer and weaker significant correlations were seen with behavior ratings scales, and significant associations also occurred with WISC-IV Verbal Comprehension and Perceptual Reasoning. The overall pattern of relations is supportive of the validity of the IVA + Plus; however, general cognitive ability was associated with better performance on most of the primary scores of the IVA + Plus, suggesting that interpretation should take intelligence into account.

  9. Prediction of Tungsten CMP Pad Life Using Blanket Removal Rate Data and Endpoint Data Obtained from Process Temperature and Carrier Motor Current Measurments

    International Nuclear Information System (INIS)

    Hetherington, Dale L.; Stein, David J.

    1999-01-01

    Several techniques to predict pad failure during tungsten CMP were investigated for a specific consumable set. These techniques include blanket polish rate measurements and metrics derived from two endpoint detection schemes. Blanket polish rate decreased significantly near pad failure. Metrics from the thermal endpoint technique included change in peak temperature, change in the time to reach peak temperature, and the change in the slope of the temperature trace just prior to peak temperature all as a function of pad life. Average carrier motor current before endpoint was also investigated. Changes in these metrics were observed however these changes, excluding time to peak process temperature, were either not consistent between pads or too noisy to be reliable predictors of pad failure

  10. Taxa de respiração de cenouras minimamente processadas e armazenadas em diferentes temperaturas Respiration rate of storage processed carrots at different temperatures

    Directory of Open Access Journals (Sweden)

    Wigberto Antonio Spagnol

    2006-09-01

    Full Text Available Entre as hortaliças minimamente processadas, a cenoura é uma das mais populares, sendo comercializada de várias maneiras: raladas, cortadas em fatias, palitos, e ainda apresentadas na forma de mini-cenoura (baby carrot. O objetivo deste estudo foi determinar as taxas respiratórias de cenouras (Daucus carota da cultivar Nantes minimamente processadas. O armazenamento foi realizado nas temperaturas de 1 °C, 5 °C e 11 °C, e 90% UR. A taxa respiratória foi determinada usando um fluxo contínuo de ar. O teor de CO2 e etileno foi medido por um cromatógrafo a gás. A taxa de respiração para as cenouras fatiadas foi mais alta do que para os produtos inteiros. Os valores da energia de ativação obtidos para as cenouras fatiadas e inteiras foi de 69,82 kJmol-1 e 54,60 kJmol-1, respectivamente. A produção de etileno foi insignificante para as cenouras durante os 14 dias de armazenamento.The carrot is one of the most popular vegetables from minimally processed vegetables. It is commercialized in many different ways: shreds, slices, sticks and baby carrots. The aim of this work is to determine the respiration rate of minimally processed carrots. They were in storage at temperatures of 1 °C, 5 °C and 11 °C, and 90% RH. The respiration rate was determined using continuous humidification airflow and measuring the CO2 concentration using a gas chromatograph connected to a microcomputer. The respiration rates of the minimally processed carrots showed a higher respiration rate than for the whole products. The activation energy values calculated for the minimally processed carrots corresponded to 69.82 kJmol-1 for the whole products. The ethylene production for the carrots remained insignificant throughout the 14 days of storage.

  11. Effect of mixing rate and temperature on primary Si phase of hypereutectic Al-20Si alloy during controlled diffusion solidification (CDS process

    Directory of Open Access Journals (Sweden)

    Yuan-dong Li

    2015-05-01

    Full Text Available Controlled Diffusion Solidification (CDS is a promising process relied on mixing two liquid alloys of precisely controlled chemistry and temperature in order to produce a predetermined alloy composition. In this study, the CDS was employed to prepare hypereutectic Al-20%Si (mass fraction alloy using Al-30%Si and pure Al of different temperatures. The mixing rate was controlled using three small crucibles with a hole of different diameters in their bottom. The effect of mixing rate and temperature on the microstructure of the primary Si-phase during the mixing of molten Al and Al-30%Si was studied. The results showed that when the diameter of the small crucible bottom hole is 16 mm, a higher mass mixing rate 0.217 kg·s-1 would results in a lower stream velocity 0.414 m·s-1. Conversely a lower mass mixing rate 0.114 kg·s-1 (the diameter of the small crucible bottom hole is 8 mm would result in a higher fluid stream velocity 0.879 m·s-1. A lower mass mixing rate would be better to refine the primary Si than a higher mass mixing rate. Meanwhile, the morphology and distribution of primary Si could also be improved. Especially, when Al-30%Si alloy at 820 °C was mixed with pure Al at 670 °C in the case of a mass mixing rate of 0.114 kg·s-1 and a pouring temperature of 680 °C, the average size of the primary Si phase would be only 18.2 μm. Its morphology would mostly be octahedral and the primary Si would distribute uniformly in the matrix microstructure. The lower mass mixing rate (0.114 kg·s-1 will enhance the broken tendency of Al-30%Si steam and the mixing agitation of resultant melt, so the primary Si phase can be better refined.

  12. Field Data Collection Methods and Data Processing of the Influence of Low Momentum Ratio and the Rate of Sediment Transport Forcing on Confluence Hydrodynamics, Morphodynamics and Mixing

    Science.gov (United States)

    Moradi, Gelare; Cardot, Romain; Lane, Stuart; Rennie, Colin

    2017-04-01

    River confluences are zones where two or more rivers join and form a single channel downstream of their junction. Because of their essential role in the dynamic of fluvial networks, there has been an increase in the attention given to their hydrodynamics and morphodynamics during last three decades. Despite this increased understanding of the complex flow behavior and morphological aspects, few studies has been focused on low momentum ratio river confluences and mixing processes. As among these few studies, most of them have been driven by the mean of laboratory experiments and numerical models, a combination of field data collection and data processing is required to study the effect of low momentum ratio on flow dynamic, rive morphology and rate of mixing in river confluences. In the present poster, the flow discharge and velocity data of two upper Rhône river confluences in Switzerland, which are characterized by low momentum ratio and a varied rate of poorly sorted sediment transport is shown. The data set is mostly collected, using spatial distributed acoustic Doppler current profiling (aDcp) measurements. The morphological changes are studied using a combination of high-resolution aerial imagery data obtained by a phantom drone and acoustic bathymetric surveys. The mixing processes are investigated by measuring the surface water temperature with a thermic camera mounted on an E-bee drone [, whereas sediment pathways can be explored through the use of the 'bottom-tracking' feature of the aDcp device (not sure there will be such results at the conference time)]. These collected data is processed using a matlab code, Pix4D and visualization software. These processed data then can be used to describe the flow behavior, morphological aspects and mixing processes at river confluences characterized by low momentum ratio and to test laboratory derived conceptual models of flow processes at such junctions. The obtained results can be used under a wider range of

  13. Investigating the effect of gas flow rate, inlet ozone concentration and relative humidity on the efficacy of catalytic ozonation process in the removal of xylene from waste airstream

    Directory of Open Access Journals (Sweden)

    H.R. MokaramI

    2010-10-01

    Full Text Available Background and aimsThe catalytic ozonation is an efficient process for the degradation of volatile organic compounds from contaminated air stream. This study was aimed at investigating the efficacy of catalytic ozonation process in removal of xylene from the polluted air stream andthe influence of retention time (gas flow rate, inlet ozone dose and relative humidity on this performanceMethodsthe catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selectedoperational variables.ResultsThe results indicated that the efficiency of catalytic ozonation was greater than that of single adsorption in removal of xylene under similar inlet concentration and relative humidity. We found a significant catalytic effect for activated carbon when used in combination with ozonation process, leading to improvement of xylene removal percentage. In addition, the elimination capacity of the system improved with the increase of inlet ozone dose as well as gas flow rate. The relative humidity showed a positive effect of the xylene removal at the range of 5 to 50%, while the higher humidity (more than 50% resulted in reduction of the performance.ConclusionThe findings of the present work revealed that the catalytic ozonation process can be an efficient technique for treating the air streams containing industrial concentrations of xylene. Furthermore, there is a practical potential to retrofit the present adsorption systems intothe catalytic ozonation simply by coupling them with the ozonation system. the catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selected

  14. High-Rate Fabrication of a-Si-Based Thin-Film Solar Cells Using Large-Area VHF PECVD Processes

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Xunming [University of Toledo; Fan, Qi Hua

    2011-12-31

    The University of Toledo (UT), working in concert with it’s a-Si-based PV industry partner Xunlight Corporation (Xunlight), has conducted a comprehensive study to develop a large-area (3ft x 3ft) VHF PECVD system for high rate uniform fabrication of silicon absorber layers, and the large-area VHF PECVD processes to achieve high performance a-Si/a-SiGe or a-Si/nc-Si tandem junction solar cells during the period of July 1, 2008 to Dec. 31, 2011, under DOE Award No. DE-FG36-08GO18073. The project had two primary goals: (i) to develop and improve a large area (3 ft × 3 ft) VHF PECVD system for high rate fabrication of > = 8 Å/s a-Si and >= 20 Å/s nc-Si or 4 Å/s a-SiGe absorber layers with high uniformity in film thicknesses and in material structures. (ii) to develop and optimize the large-area VHF PECVD processes to achieve high-performance a-Si/nc-Si or a-Si/a-SiGe tandem-junction solar cells with >= 10% stable efficiency. Our work has met the goals and is summarized in “Accomplishments versus goals and objectives”.

  15. A Study of Parameters Related to the Etch Rate for a Dry Etch Process Using NF3/O2 and SF6/O2

    Directory of Open Access Journals (Sweden)

    Seon-Geun Oh

    2014-01-01

    Full Text Available The characteristics of the dry etching of SiNx:H thin films for display devices using SF6/O2 and NF3/O2 were investigated using a dual-frequency capacitively coupled plasma reactive ion etching (CCP-RIE system. The investigation was carried out by varying the RF power ratio (13.56 MHz/2 MHz, pressure, and gas flow ratio. For the SiNx:H film, the etch rates obtained using NF3/O2 were higher than those obtained using SF6/O2 under various process conditions. The relationships between the etch rates and the usual monitoring parameters—the optical emission spectroscopy (OES intensity of atomic fluorine (685.1 nm and 702.89 nm and the voltages VH and VL—were investigated. The OES intensity data indicated a correlation between the bulk plasma density and the atomic fluorine density. The etch rate was proportional to the product of the OES intensity of atomic fluorine (I(F and the square root of the voltages (Vh+Vl on the assumption that the velocity of the reactive fluorine was proportional to the square root of the voltages.

  16. Investigating the timing of origin and evolutionary processes shaping regional species diversity: Insights from simulated data and neotropical butterfly diversification rates.

    Science.gov (United States)

    Matos-Maraví, Pável

    2016-07-01

    Different diversification scenarios have been proposed to explain the origin of extant biodiversity. However, most existing meta-analyses of time-calibrated phylogenies rely on approaches that do not quantitatively test alternative diversification processes. Here, I highlight the shortcomings of using species divergence ranks, which is a method widely used in meta-analyses. Divergence ranks consist of categorizing cladogenetic events to certain periods of time, typically to either Pleistocene or to pre-Pleistocene ages. This approach has been claimed to shed light on the origin of most extant species and the timing and dynamics of diversification in any biogeographical region. However, interpretations drawn from such method often confound two fundamental questions in macroevolutionary studies, tempo (timing of evolutionary rate shifts) and mode ("how" and "why" of speciation). By using simulated phylogenies under four diversification scenarios, constant-rate, diversity-dependence, high extinction, and high speciation rates in the Pleistocene, I showed that interpretations based on species divergence ranks might have been seriously misleading. Future meta-analyses of dated phylogenies need to be aware of the impacts of incomplete taxonomic sampling, tree topology, and divergence time uncertainties, as well as they might be benefited by including quantitative tests of alternative diversification models that acknowledge extinction and diversity dependence. © 2016 The Author(s).

  17. Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

    Directory of Open Access Journals (Sweden)

    B. Orcutt

    2008-11-01

    Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal were examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species can cause the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, none of the potential intermediates considered here is able to support metabolic activity matching the measured rates.

  18. Effect of directional solidification rate on the microstructure and properties of deformation-processed Cu–7Cr–0.1Ag in situ composites

    International Nuclear Information System (INIS)

    Liu, Keming; Jiang, Zhengyi; Zhao, Jingwei; Zou, Jin; Chen, Zhibao; Lu, Deping

    2014-01-01

    Highlights: • Effect of directional solidification (DS) rate on a Cu–Cr–Ag in situ composite. • The microstructure and properties of the DS in situ composite were investigated. • The second-phase Cr grains were parallel to drawing direction, and were finer. • The tensile strength was higher and the combination of properties was better. - Abstract: The influence of directional solidification rate on the microstructure, mechanical properties and conductivity of deformation-processed Cu–7Cr–0.1Ag in situ composites produced by thermo-mechanical processing was systematically investigated. The microstructure was analyzed by optical microscopy and scanning electronic microscopy. The mechanical properties and conductivity were evaluated by tensile-testing machine and micro-ohmmeter, respectively. The results indicate that the size, shape and distribution of second-phase Cr grains are significantly different in the Cu–7Cr–0.1Ag alloys with different growth rates. At a growth rate of 200 μm s −1 , the Cr grains transform into fine Cr fiber-like grains parallel to the pulling direction from the Cr dendrites. The tensile strength of the Cu–7Cr–0.1Ag in situ composites from the directional solidification (DS) alloys is significantly higher than that from the as-cast alloy, while the conductivity of the in situ composites from the DS alloys is slightly lower than that from the as-cast alloy. The following combinations of tensile strength, elongation to fracture and conductivity of the Cu–7Cr–0.1Ag in situ composites from the DS alloy with a growth rate of 200 μm s −1 and a cumulative cold deformation strain of 8 after isochronic aging treatment for 1 h can be obtained respectively as: (i) 1067 MPa, 2.9% and 74.9% IACS; or (ii) 1018 MPa, 3.0%, and 76.0% IACS or (iii) 906 MPa, 3.3% and 77.6% IACS

  19. Effect of directional solidification rate on the microstructure and properties of deformation-processed Cu–7Cr–0.1Ag in situ composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Keming [Jiangxi Key Laboratory for Advanced Copper and Tungsten Materials, Jiangxi Academy of Sciences, Nanchang 330029 (China); School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Jiang, Zhengyi; Zhao, Jingwei [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, NSW 2522 (Australia); Zou, Jin; Chen, Zhibao [Jiangxi Key Laboratory for Advanced Copper and Tungsten Materials, Jiangxi Academy of Sciences, Nanchang 330029 (China); Lu, Deping, E-mail: llludp@163.com [Jiangxi Key Laboratory for Advanced Copper and Tungsten Materials, Jiangxi Academy of Sciences, Nanchang 330029 (China)

    2014-11-05

    Highlights: • Effect of directional solidification (DS) rate on a Cu–Cr–Ag in situ composite. • The microstructure and properties of the DS in situ composite were investigated. • The second-phase Cr grains were parallel to drawing direction, and were finer. • The tensile strength was higher and the combination of properties was better. - Abstract: The influence of directional solidification rate on the microstructure, mechanical properties and conductivity of deformation-processed Cu–7Cr–0.1Ag in situ composites produced by thermo-mechanical processing was systematically investigated. The microstructure was analyzed by optical microscopy and scanning electronic microscopy. The mechanical properties and conductivity were evaluated by tensile-testing machine and micro-ohmmeter, respectively. The results indicate that the size, shape and distribution of second-phase Cr grains are significantly different in the Cu–7Cr–0.1Ag alloys with different growth rates. At a growth rate of 200 μm s{sup −1}, the Cr grains transform into fine Cr fiber-like grains parallel to the pulling direction from the Cr dendrites. The tensile strength of the Cu–7Cr–0.1Ag in situ composites from the directional solidification (DS) alloys is significantly higher than that from the as-cast alloy, while the conductivity of the in situ composites from the DS alloys is slightly lower than that from the as-cast alloy. The following combinations of tensile strength, elongation to fracture and conductivity of the Cu–7Cr–0.1Ag in situ composites from the DS alloy with a growth rate of 200 μm s{sup −1} and a cumulative cold deformation strain of 8 after isochronic aging treatment for 1 h can be obtained respectively as: (i) 1067 MPa, 2.9% and 74.9% IACS; or (ii) 1018 MPa, 3.0%, and 76.0% IACS or (iii) 906 MPa, 3.3% and 77.6% IACS.

  20. EFFECT OF FEED PROCESSING ON VOLATILE FATTY ACID PRODUCTION RATES MEASURED WITH 13C-ACETATE IN GRAZING LACTATING DAIRY COWS

    Directory of Open Access Journals (Sweden)

    R. Tothi

    2007-06-01

    Full Text Available The effect of processed cereal grain supplementation on volatile fatty acid (VFA production rates of grazing, lactating Holstein-Friesian cows were measured in a 5x5 Latin square experiment. The experimental treatments were as follows: control (only grazing, no supplement addition, NS, pelleted barley (PB, pelleted maize (PM, toasted and subsequently pelleted barley (TPB, and toasted and subsequently pelleted maize (TPM as supplements. An isotope dilution technique using stable isotope of carbon (13C as an internal marker was employed for the estimation of VFA production. At the beginning of a 3-hour long allowed grazing time, 100 mg of 99% enriched 13C2 Na-acetate were introduced in the rumen and repeated after grazing with 50 mg isotope, after which the cows were starved for 6 hours until evening milking. During grazing disappearance rate (kdis and production rate (kprod of acetate, propionate and butyrate were significantly higher (P≤0.05 in supplemented than in NS cows. Moreover the effect of barley grain and pelleting treatment was higher than the effect of maize grain and toasting. During starvation significantly higher (P≤0.05 kdis and kprod of VFAs were observed in PM and TPM treatments. Total VFA production for the experimental period (grazing + starvation were 49.5, 78.7, 69.9, 88.5, 80.8 mol/day for NS, PB, TPB, PM and TPM, respectively. The higher VFA productions measured in supplemented animals emphasis the extensive digestion that occurs in the rumen after feeding processed grains. In methodological terms, 13C2 Na-acetate labelling appears to be a useful means for examining the VFA acetate production in ruminants.