WorldWideScience

Sample records for two-stage physical process

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

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  2. Dynamic Modelling of the Two-stage Gasification Process

    DEFF Research Database (Denmark)

    Gøbel, Benny; Henriksen, Ulrik B.; Houbak, Niels

    1999-01-01

    A two-stage gasification pilot plant was designed and built as a co-operative project between the Technical University of Denmark and the company REKA.A dynamic, mathematical model of the two-stage pilot plant was developed to serve as a tool for optimising the process and the operating conditions...... of the gasification plant.The model consists of modules corresponding to the different elements in the plant. The modules are coupled together through mass and heat conservation.Results from the model are compared with experimental data obtained during steady and unsteady operation of the pilot plant. A good...

  3. Lightweight Concrete Produced Using a Two-Stage Casting Process

    Directory of Open Access Journals (Sweden)

    Jin Young Yoon

    2015-03-01

    Full Text Available The type of lightweight aggregate and its volume fraction in a mix determine the density of lightweight concrete. Minimizing the density obviously requires a higher volume fraction, but this usually causes aggregates segregation in a conventional mixing process. This paper proposes a two-stage casting process to produce a lightweight concrete. This process involves placing lightweight aggregates in a frame and then filling in the remaining interstitial voids with cementitious grout. The casting process results in the lowest density of lightweight concrete, which consequently has low compressive strength. The irregularly shaped aggregates compensate for the weak point in terms of strength while the round-shape aggregates provide a strength of 20 MPa. Therefore, the proposed casting process can be applied for manufacturing non-structural elements and structural composites requiring a very low density and a strength of at most 20 MPa.

  4. Two stages kinetics of municipal solid waste inoculation composting processes

    Institute of Scientific and Technical Information of China (English)

    XI Bei-dou1; HUANG Guo-he; QIN Xiao-sheng; LIU Hong-liang

    2004-01-01

    In order to understand the key mechanisms of the composting processes, the municipal solid waste(MSW) composting processes were divided into two stages, and the characteristics of typical experimental scenarios from the viewpoint of microbial kinetics was analyzed. Through experimentation with advanced composting reactor under controlled composting conditions, several equations were worked out to simulate the degradation rate of the substrate. The equations showed that the degradation rate was controlled by concentration of microbes in the first stage. The degradation rates of substrates of inoculation Run A, B, C and Control composting systems were 13.61 g/(kg·h), 13.08 g/(kg·h), 15.671 g/(kg·h), and 10.5 g/(kg·h), respectively. The value of Run C is around 1.5 times higher than that of Control system. The decomposition rate of the second stage is controlled by concentration of substrate. Although the organic matter decomposition rates were similar to all Runs, inoculation could reduce the values of the half velocity coefficient and could be more efficient to make the composting stable. Particularly. For Run C, the decomposition rate is high in the first stage, and is low in the second stage. The results indicated that the inoculation was efficient for the composting processes.

  5. Performance analysis of RDF gasification in a two stage fluidized bed-plasma process.

    Science.gov (United States)

    Materazzi, M; Lettieri, P; Taylor, R; Chapman, C

    2016-01-01

    The major technical problems faced by stand-alone fluidized bed gasifiers (FBG) for waste-to gas applications are intrinsically related to the composition and physical properties of waste materials, such as RDF. The high quantity of ash and volatile material in RDF can provide a decrease in thermal output, create high ash clinkering, and increase emission of tars and CO2, thus affecting the operability for clean syngas generation at industrial scale. By contrast, a two-stage process which separates primary gasification and selective tar and ash conversion would be inherently more forgiving and stable. This can be achieved with the use of a separate plasma converter, which has been successfully used in conjunction with conventional thermal treatment units, for the ability to 'polish' the producer gas by organic contaminants and collect the inorganic fraction in a molten (and inert) state. This research focused on the performance analysis of a two-stage fluid bed gasification-plasma process to transform solid waste into clean syngas. Thermodynamic assessment using the two-stage equilibrium method was carried out to determine optimum conditions for the gasification of RDF and to understand the limitations and influence of the second stage on the process performance (gas heating value, cold gas efficiency, carbon conversion efficiency), along with other parameters. Comparison with a different thermal refining stage, i.e. thermal cracking (via partial oxidation) was also performed. The analysis is supported by experimental data from a pilot plant.

  6. Terephthalic acid wastewater treatment by using two-stage aerobic process

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Based on the tests between anoxic and aerobic process, the two-stage aerobic process with a biological selector was chosen to treat terephthalic acid wastewater (PTA). By adopting the two- stage aerobic process, the CODCr in PTA wastewater could be reduced from 4000-6000 mg/L to below 100 mg/L; the COD loading in the first aerobic tank could reach 7.0-8.0 kgCODCr/(m3.d) and that of the second stage was from 0.2 to 0.4 kgCODCr/(m3.d). Further researches on the kinetics of substrate degradation were carried out.

  7. Innovative two-stage anaerobic process for effective codigestion of cheese whey and cattle manure.

    Science.gov (United States)

    Bertin, Lorenzo; Grilli, Selene; Spagni, Alessandro; Fava, Fabio

    2013-01-01

    The valorisation of agroindustrial waste through anaerobic digestion represents a significant opportunity for refuse treatment and renewable energy production. This study aimed to improve the codigestion of cheese whey (CW) and cattle manure (CM) by an innovative two-stage process, based on concentric acidogenic and methanogenic phases, designed for enhancing performance and reducing footprint. The optimum CW to CM ratio was evaluated under batch conditions. Thereafter, codigestion was implemented under continuous-flow conditions comparing one- and two-stage processes. The results demonstrated that the addition of CM in codigestion with CW greatly improved the anaerobic process. The highest methane yield was obtained co-treating the two substrates at equal ratio by using the innovative two-stage process. The proposed system reached the maximum value of 258 mL(CH4) g(gv(-1), which was more than twice the value obtained by the one-stage process and 10% higher than the value obtained by the two-stage one.

  8. ADM1-based modeling of methane production from acidified sweet sorghum extractin a two stage process

    DEFF Research Database (Denmark)

    Antonopoulou, Georgia; Gavala, Hariklia N.; Skiadas, Ioannis

    2012-01-01

    The present study focused on the application of the Anaerobic Digestion Model 1 οn the methane production from acidified sorghum extract generated from a hydrogen producing bioreactor in a two-stage anaerobic process. The kinetic parameters for hydrogen and volatile fatty acids consumption were...

  9. The rearrangement process in a two-stage broadcast switching network

    DEFF Research Database (Denmark)

    Jacobsen, Søren B.

    1988-01-01

    The rearrangement process in the two-stage broadcast switching network presented by F.K. Hwang and G.W. Richards (ibid., vol.COM-33, no.10, p.1025-1035, Oct. 1985) is considered. By defining a certain function it is possible to calculate an upper bound on the number of connections to be moved...

  10. Biological hydrogen production from olive mill wastewater with two-stage processes

    Energy Technology Data Exchange (ETDEWEB)

    Eroglu, Ela; Eroglu, Inci [Department of Chemical Engineering, Middle East Technical University, 06531, Ankara (Turkey); Guenduez, Ufuk; Yuecel, Meral [Department of Biology, Middle East Technical University, 06531, Ankara (Turkey); Tuerker, Lemi [Department of Chemistry, Middle East Technical University, 06531, Ankara (Turkey)

    2006-09-15

    In the present work two novel two-stage hydrogen production processes from olive mill wastewater (OMW) have been introduced. The first two-stage process involved dark-fermentation followed by a photofermentation process. Dark-fermentation by activated sludge cultures and photofermentation by Rhodobacter sphaeroides O.U.001 were both performed in 55ml glass vessels, under anaerobic conditions. In some cases of dark-fermentation, activated sludge was initially acclimatized to the OMW to provide the adaptation of microorganisms to the extreme conditions of OMW. The highest hydrogen production potential obtained was 29l{sub H{sub 2}}/l{sub OMW} after photofermentation with 50% (v/v) effluent of dark fermentation with activated sludge. Photofermentation with 50% (v/v) effluent of dark fermentation with acclimated activated sludge had the highest hydrogen production rate (0.008ll{sup -1}h{sup -1}). The second two-stage process involved a clay treatment step followed by photofermentation by R. sphaeroides O.U.001. Photofermentation with the effluent of the clay pretreatment process (4% (v/v)) gives the highest hydrogen production potential (35l{sub H{sub 2}}/l{sub OMW}), light conversion efficiency (0.42%) and COD conversion efficiency (52%). It was concluded that both pretreatment processes enhanced the photofermentative hydrogen production process. Moreover, hydrogen could be produced with highly concentrated OMW. Two-stage processes developed in the present investigation have a high potential for solving the environmental problems caused by OMW. (author)

  11. Two-stage precipitation process of iron and arsenic from acid leaching solutions

    Institute of Scientific and Technical Information of China (English)

    N.J.BOLIN; J.E.SUNDKVIST

    2008-01-01

    A leaching process for base metals recovery often generates considerable amounts of impurities such as iron and arsenic into the solution.It is a challenge to separate the non-valuable metals into manageable and stable waste products for final disposal,without loosing the valuable constituents.Boliden Mineral AB has patented a two-stage precipitation process that gives a very clean iron-arsenic precipitate by a minimum of coprecipitation of base metals.The obtained product shows to have good sedimentation and filtration properties,which makes it easy to recover the iron-arsenic depleted solution by filtration and washing of the precipitate.Continuos bench scale tests have been done,showing the excellent results achieved by the two-stage precipitation process.

  12. HRI catalytic two-stage liquefaction (CTSL) process materials: chemical analysis and biological testing

    Energy Technology Data Exchange (ETDEWEB)

    Wright, C.W.; Later, D.W.

    1985-12-01

    This report presents data from the chemical analysis and biological testing of coal liquefaction materials obtained from the Hydrocarbon Research, Incorporated (HRI) catalytic two-stage liquefaction (CTSL) process. Materials from both an experimental run and a 25-day demonstration run were analyzed. Chemical methods of analysis included adsorption column chromatography, high-resolution gas chromatography, gas chromatography/mass spectrometry, low-voltage probe-inlet mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The biological activity was evaluated using the standard microbial mutagenicity assay and an initiation/promotion assay for mouse-skin tumorigenicity. Where applicable, the results obtained from the analyses of the CTSL materials have been compared to those obtained from the integrated and nonintegrated two-stage coal liquefaction processes. 18 refs., 26 figs., 22 tabs.

  13. HRI catalytic two-stage liquefaction (CTSL) process materials: chemical analysis and biological testing

    Energy Technology Data Exchange (ETDEWEB)

    Wright, C.W.; Later, D.W.

    1985-12-01

    This report presents data from the chemical analysis and biological testing of coal liquefaction materials obtained from the Hydrocarbon Research, Incorporated (HRI) catalytic two-stage liquefaction (CTSL) process. Materials from both an experimental run and a 25-day demonstration run were analyzed. Chemical methods of analysis included adsorption column chromatography, high-resolution gas chromatography, gas chromatography/mass spectrometry, low-voltage probe-inlet mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The biological activity was evaluated using the standard microbial mutagenicity assay and an initiation/promotion assay for mouse-skin tumorigenicity. Where applicable, the results obtained from the analyses of the CTSL materials have been compared to those obtained from the integrated and nonintegrated two-stage coal liquefaction processes. 18 refs., 26 figs., 22 tabs.

  14. Industrial demonstration plant for the gasification of herb residue by fluidized bed two-stage process.

    Science.gov (United States)

    Zeng, Xi; Shao, Ruyi; Wang, Fang; Dong, Pengwei; Yu, Jian; Xu, Guangwen

    2016-04-01

    A fluidized bed two-stage gasification process, consisting of a fluidized-bed (FB) pyrolyzer and a transport fluidized bed (TFB) gasifier, has been proposed to gasify biomass for fuel gas production with low tar content. On the basis of our previous fundamental study, an autothermal two-stage gasifier has been designed and built for gasify a kind of Chinese herb residue with a treating capacity of 600 kg/h. The testing data in the operational stable stage of the industrial demonstration plant showed that when keeping the reaction temperatures of pyrolyzer and gasifier respectively at about 700 °C and 850 °C, the heating value of fuel gas can reach 1200 kcal/Nm(3), and the tar content in the produced fuel gas was about 0.4 g/Nm(3). The results from this pilot industrial demonstration plant fully verified the feasibility and technical features of the proposed FB two-stage gasification process.

  15. Metamodeling and Optimization of a Blister Copper Two-Stage Production Process

    Science.gov (United States)

    Jarosz, Piotr; Kusiak, Jan; Małecki, Stanisław; Morkisz, Paweł; Oprocha, Piotr; Pietrucha, Wojciech; Sztangret, Łukasz

    2016-06-01

    It is often difficult to estimate parameters for a two-stage production process of blister copper (containing 99.4 wt.% of Cu metal) as well as those for most industrial processes with high accuracy, which leads to problems related to process modeling and control. The first objective of this study was to model flash smelting and converting of Cu matte stages using three different techniques: artificial neural networks, support vector machines, and random forests, which utilized noisy technological data. Subsequently, more advanced models were applied to optimize the entire process (which was the second goal of this research). The obtained optimal solution was a Pareto-optimal one because the process consisted of two stages, making the optimization problem a multi-criteria one. A sequential optimization strategy was employed, which aimed for optimal control parameters consecutively for both stages. The obtained optimal output parameters for the first smelting stage were used as input parameters for the second converting stage. Finally, a search for another optimal set of control parameters for the second stage of a Kennecott-Outokumpu process was performed. The optimization process was modeled using a Monte-Carlo method, and both modeling parameters and computed optimal solutions are discussed.

  16. Hydrogen and methane production from household solid waste in the two-stage fermentation process

    DEFF Research Database (Denmark)

    Lui, D.; Liu, D.; Zeng, Raymond Jianxiong

    2006-01-01

    A two-stage process combined hydrogen and methane production from household solid waste was demonstrated working successfully. The yield of 43 mL H-2/g volatile solid (VS) added was generated in the first hydrogen production stage and the methane production in the second stage was 500 mL CH4/g VS....... Furthermore, this study also provided direct evidence in the dynamic fermentation process that, hydrogen production increase was reflected by acetate to butyrate ratio increase in liquid phase. (c) 2006 Elsevier Ltd. All rights reserved.......A two-stage process combined hydrogen and methane production from household solid waste was demonstrated working successfully. The yield of 43 mL H-2/g volatile solid (VS) added was generated in the first hydrogen production stage and the methane production in the second stage was 500 mL CH4/g VS...... added. This figure was 21% higher than the methane yield from the one-stage process, which was run as control. Sparging of the hydrogen reactor with methane gas resulted in doubling of the hydrogen production. PH was observed as a key factor affecting fermentation pathway in hydrogen production stage...

  17. Development of a Two-Stage Microalgae Dewatering Process – A Life Cycle Assessment Approach

    Science.gov (United States)

    Soomro, Rizwan R.; Zeng, Xianhai; Lu, Yinghua; Lin, Lu; Danquah, Michael K.

    2016-01-01

    Even though microalgal biomass is leading the third generation biofuel research, significant effort is required to establish an economically viable commercial-scale microalgal biofuel production system. Whilst a significant amount of work has been reported on large-scale cultivation of microalgae using photo-bioreactors and pond systems, research focus on establishing high performance downstream dewatering operations for large-scale processing under optimal economy is limited. The enormous amount of energy and associated cost required for dewatering large-volume microalgal cultures has been the primary hindrance to the development of the needed biomass quantity for industrial-scale microalgal biofuels production. The extremely dilute nature of large-volume microalgal suspension and the small size of microalgae cells in suspension create a significant processing cost during dewatering and this has raised major concerns towards the economic success of commercial-scale microalgal biofuel production as an alternative to conventional petroleum fuels. This article reports an effective framework to assess the performance of different dewatering technologies as the basis to establish an effective two-stage dewatering system. Bioflocculation coupled with tangential flow filtration (TFF) emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass. A streamlined process for operational analysis of two-stage microalgae dewatering technique, encompassing energy input, carbon dioxide emission, and process cost, is presented. PMID:26904075

  18. Two stages of parafoveal processing during reading: Evidence from a display change detection task.

    Science.gov (United States)

    Angele, Bernhard; Slattery, Timothy J; Rayner, Keith

    2016-08-01

    We used a display change detection paradigm (Slattery, Angele, & Rayner Human Perception and Performance, 37, 1924-1938 2011) to investigate whether display change detection uses orthographic regularity and whether detection is affected by the processing difficulty of the word preceding the boundary that triggers the display change. Subjects were significantly more sensitive to display changes when the change was from a nonwordlike preview than when the change was from a wordlike preview, but the preview benefit effect on the target word was not affected by whether the preview was wordlike or nonwordlike. Additionally, we did not find any influence of preboundary word frequency on display change detection performance. Our results suggest that display change detection and lexical processing do not use the same cognitive mechanisms. We propose that parafoveal processing takes place in two stages: an early, orthography-based, preattentional stage, and a late, attention-dependent lexical access stage.

  19. A two-stage metal valorisation process from electric arc furnace dust (EAFD

    Directory of Open Access Journals (Sweden)

    H. Issa

    2016-04-01

    Full Text Available This paper demonstrates possibility of separate zinc and lead recovery from coal composite pellets, composed of EAFD with other synergetic iron-bearing wastes and by-products (mill scale, pyrite-cinder, magnetite concentrate, through a two-stage process. The results show that in the first, low temp erature stage performed in electro-resistant furnace, removal of lead is enabled due to presence of chlorides in the system. In the second stage, performed at higher temperatures in Direct Current (DC plasma furnace, valorisation of zinc is conducted. Using this process, several final products were obtained, including a higher purity zinc oxide, which, by its properties, corresponds washed Waelz oxide.

  20. ADM1-based modeling of methane production from acidified sweet sorghum extractin a two stage process

    DEFF Research Database (Denmark)

    Antonopoulou, Georgia; Gavala, Hariklia N.; Skiadas, Ioannis

    2012-01-01

    The present study focused on the application of the Anaerobic Digestion Model 1 οn the methane production from acidified sorghum extract generated from a hydrogen producing bioreactor in a two-stage anaerobic process. The kinetic parameters for hydrogen and volatile fatty acids consumption were...... estimated through fitting of the model equations to the data obtained from batch experiments. The simulation of the continuous reactor performance at all HRTs tested (20, 15 and 10d) was very satisfactory. Specifically, the largest deviation of the theoretical predictions against the experimental data...... was 12% for the methane production rate at the HRT of 20d while the deviation values for the 15 and 10 d HRT were 1.9% and 1.1%, respectively. The model predictions regarding pH, methane percentage in the gas phase and COD removal were in very good agreement with the experimental data with a deviation...

  1. Treatment of Domestic Sewage by Two-Stage-Bio-Contact Oxidation Process

    Institute of Scientific and Technical Information of China (English)

    LI Xiang-dong; FENG Qi-yan; LIU Zhong-wei; XIAO Xin; LIN Guo-hua

    2005-01-01

    Effects of hydraulic retention time (HRT) and gas volume on efficiency of wastewater treatment are discussed based on a simulation experiment in which the domestic swage was treated by the two-stage-bio-contact oxidation process. The result shows that the average CODcr, BOD5, suspended solid (SS), and ammonia-nitrogen removal rate are 94.5 %, 93.2 %, 91.7 % and 46.9 %, respectively, under the conditions of a total air/water ratio of 5: 1 , an air/water ratio of 3:1 for oxidation tank 1 and 2:1for oxidation tank 2 and a hydraulic retention time of 1 h for each stage. This method is suitable for domestic sewage treatment of residential community and small towns as well.

  2. Synchronous rapid start-up of the methanation and anammox processes in two-stage ASBRs

    Science.gov (United States)

    Duan, Y.; Li, W. R.; Zhao, Y.

    2017-01-01

    The “methanation + anaerobic ammonia oxidation autotrophic denitrification” method was adopted by using anaerobic sequencing batch reactors (ASBRs) and realized a satisfactory synchronous removal of chemical oxygen demand (COD) and ammonia-nitrogen (NH4 +-N) in wastewater after 75 days operation. 90% of COD was removed at a COD load of 1.2 kg/(m3•d) and 90% of TN was removed at a TN load of 0.14 kg/(m3•d). The anammox reaction ratio was estimated to be 1: 1.32: 0.26. The results showed that synchronous rapid start-up of the methanation and anaerobic ammonia oxidation processes in two-stage ASBRs was feasible.

  3. Ecotoxicity of materials from integrated two-stage liquefaction and Exxon Donor Solvent processes

    Energy Technology Data Exchange (ETDEWEB)

    Dauble, D.D.; Scott, A.J.; Lusty, E.W.; Thomas, B.L.; Hanf, R.W. Jr.

    1983-05-01

    Coal-derived materials from two coal conversion processes were screened for potential ecological toxicity. We examined the toxicity of materials from different engineering or process options to an aquatic invertebrate and also related potential hazard to relative concentration, composition, and stability of water soluble components. For materials tested from the Integrated Two-Stage Liquefaction (ITSL) process, only the LC finer (LCF) 650/sup 0/F distillate was highly soluble in water at 20/sup 0/C. The LCF feed and Total Liquid Product (TLP) were not in liquid state at 20/sup 0/C and were relatively insoluble in water. Relative hazard to daphnids from ITSL materials was as follows: LCF 650/sup 0/F distillate greater than or equal to LCF feed greater than or equal to TLP. For Exxon Donor Solvent (EDS) materials, process solvent produced in the bottoms recycle mode was more soluble in water than once-through process solvent and, hence, slightly more acutely toxic to daphnids. When compared to other coal liquids or petroleum products, the ITSL or EDS liquids were intermediate in toxicity; relative hazard ranged from 1/7 to 1/13 of the Solvent Refined Coal (SRC)-II distillable blend, but was several times greater than the relative hazard for No. 2 diesel fuel oil or Prudhoe Bay crude oil. Although compositonal differences in water-soluble fractions (WSF) were noted among materials, phenolics were the major compound class in all WSFs and probably the primary contributor to acute toxicity.

  4. Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process

    DEFF Research Database (Denmark)

    Luo, Gang; Xie, Li; Zhou, Qi

    2011-01-01

    The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single......-stage methanogenic process (HRT 15d) under organic loading rate (OLR) 3gVS/(Ld). The two-stage process was still stable when the OLR was increased to 4.5gVS/(Ld), while the single-stage process failed. The study further revealed that by changing the HRThydrogen:HRTmethane ratio of the two-stage process from 3...

  5. Hydrogen and methane production from household solid waste in the two-stage fermentation process.

    Science.gov (United States)

    Liu, Dawei; Liu, Dapeng; Zeng, Raymond J; Angelidaki, Irini

    2006-06-01

    A two-stage process combined hydrogen and methane production from household solid waste was demonstrated working successfully. The yield of 43 mL H(2)/g volatile solid (VS) added was generated in the first hydrogen production stage and the methane production in the second stage was 500 mL CH(4)/g VS added. This figure was 21% higher than the methane yield from the one-stage process, which was run as control. Sparging of the hydrogen reactor with methane gas resulted in doubling of the hydrogen production. pH was observed as a key factor affecting fermentation pathway in hydrogen production stage. The optimum pH range for hydrogen production in this system was in the range from 5 to 5.5. The short hydraulic retention time (2 days) applied in the first stage was enough to separate acidogenesis from methanogenesis. No additional control for preventing methanogenesis in the first stage was necessary. Furthermore, this study also provided direct evidence in the dynamic fermentation process that, hydrogen production increase was reflected by acetate to butyrate ratio increase in liquid phase.

  6. Food behavior change in late-life widowhood: A two-stage process.

    Science.gov (United States)

    Vesnaver, Elisabeth; Keller, Heather H; Sutherland, Olga; Maitland, Scott B; Locher, J L

    2015-12-01

    Widowhood is a common life event for married older women. Prior research has found disruptions in eating behaviors to be common among widows. Little is known about the process underlying these disruptions. The aim of this study was to generate a theoretical understanding of the changing food behaviors of older women during the transition of widowhood. Qualitative methods based on constructivist grounded theory guided by a critical realist worldview were used. Individual active interviews were conducted with 15 community-living women, aged 71-86 years, living alone, and widowed six months to 15 years at the time of the interview. Participants described a variety of educational backgrounds and levels of health, were mainly white and of Canadian or European descent, and reported sufficient income to meet their needs. The loss of regular shared meals initiated a two-stage process whereby women first fall into new patterns and then re-establish the personal food system, thus enabling women to redirect their food system from one that satisfied the couple to one that satisfied their personal food needs. Influences on the trajectory of the change process included the couple's food system, experience with nutritional care, food-related values, and food-related resources. Implications for research and practice are discussed.

  7. Hydrogen and methane production from condensed molasses fermentation soluble by a two-stage anaerobic process

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chiu-Yue; Liang, You-Chyuan; Lay, Chyi-How [Feng Chia Univ., Taichung, Taiwan (China). Dept. of Environmental Engineering and Science; Chen, Chin-Chao [Chungchou Institute of Technology, Taiwan (China). Environmental Resources Lab.; Chang, Feng-Yuan [Feng Chia Univ., Taichung, Taiwan (China). Research Center for Energy and Resources

    2010-07-01

    The treatment of condensed molasses fermentation soluble (CMS) is a troublesome problem for glutamate manufacturing factory. However, CMS contains high carbohydrate and nutrient contents and is an attractive and commercially potential feedstock for bioenergy production. The aim of this paper is to produce hydrogen and methane by two-stage anaerobic fermentation process. The fermentative hydrogen production from CMS was conducted in a continuously-stirred tank bioreactor (working volume 4 L) which was operated at a hydraulic retention time (HRT) of 8 h, organic loading rate (OLR) of 120 kg COD/m{sup 3}-d, temperature of 35 C, pH 5.5 and sewage sludge as seed. The anaerobic methane production was conducted in an up-flow bioreactor (working volume 11 L) which was operated at a HRT of 24 -60 hrs, OLR of 4.0-10 kg COD/m{sup 3}-d, temperature of 35 C, pH 7.0 with using anaerobic granule sludge from fructose manufacturing factory as the seed and the effluent from hydrogen production process as the substrate. These two reactors have been operated successfully for more than 400 days. The steady-state hydrogen content, hydrogen production rate and hydrogen production yield in the hydrogen fermentation system were 37%, 169 mmol-H{sub 2}/L-d and 93 mmol-H{sub 2}/g carbohydrate{sub removed}, respectively. In the methane fermentation system, the peak methane content and methane production rate were 66.5 and 86.8 mmol-CH{sub 4}/L-d with methane production yield of 189.3 mmol-CH{sub 4}/g COD{sub removed} at an OLR 10 kg/m{sup 3}-d. The energy production rate was used to elucidate the energy efficiency for this two-stage process. The total energy production rate of 133.3 kJ/L/d was obtained with 5.5 kJ/L/d from hydrogen fermentation and 127.8 kJ/L/d from methane fermentation. (orig.)

  8. Hydrogen production from cellulose in a two-stage process combining fermentation and electrohydrogenesis

    KAUST Repository

    Lalaurette, Elodie

    2009-08-01

    A two-stage dark-fermentation and electrohydrogenesis process was used to convert the recalcitrant lignocellulosic materials into hydrogen gas at high yields and rates. Fermentation using Clostridium thermocellum produced 1.67 mol H2/mol-glucose at a rate of 0.25 L H2/L-d with a corn stover lignocellulose feed, and 1.64 mol H2/mol-glucose and 1.65 L H2/L-d with a cellobiose feed. The lignocelluose and cellobiose fermentation effluent consisted primarily of: acetic, lactic, succinic, and formic acids and ethanol. An additional 800 ± 290 mL H2/g-COD was produced from a synthetic effluent with a wastewater inoculum (fermentation effluent inoculum; FEI) by electrohydrogensis using microbial electrolysis cells (MECs). Hydrogen yields were increased to 980 ± 110 mL H2/g-COD with the synthetic effluent by combining in the inoculum samples from multiple microbial fuel cells (MFCs) each pre-acclimated to a single substrate (single substrate inocula; SSI). Hydrogen yields and production rates with SSI and the actual fermentation effluents were 980 ± 110 mL/g-COD and 1.11 ± 0.13 L/L-d (synthetic); 900 ± 140 mL/g-COD and 0.96 ± 0.16 L/L-d (cellobiose); and 750 ± 180 mL/g-COD and 1.00 ± 0.19 L/L-d (lignocellulose). A maximum hydrogen production rate of 1.11 ± 0.13 L H2/L reactor/d was produced with synthetic effluent. Energy efficiencies based on electricity needed for the MEC using SSI were 270 ± 20% for the synthetic effluent, 230 ± 50% for lignocellulose effluent and 220 ± 30% for the cellobiose effluent. COD removals were ∼90% for the synthetic effluents, and 70-85% based on VFA removal (65% COD removal) with the cellobiose and lignocellulose effluent. The overall hydrogen yield was 9.95 mol-H2/mol-glucose for the cellobiose. These results show that pre-acclimation of MFCs to single substrates improves performance with a complex mixture of substrates, and that high hydrogen yields and gas production rates can be achieved using a two-stage fermentation and MEC

  9. TEXTURAL AND CHEMICAL CHARACTERISATION OF ACTIVATED CARBONS PREPARED FROM RICE HUSK (ORYZA SATIVA USING A TWO- STAGE ACTIVATION PROCESS

    Directory of Open Access Journals (Sweden)

    JOSEPH G. COLLIN

    2008-12-01

    Full Text Available Activated carbons from agro-industrial wastes; rice husk; were prepared by physical and chemical activation using phosphoric acid as the dehydrating agent. A two-stage activation process method was used; with semi-carbonisation stage at 200oC for 15 minutes as the first stage followed by an activation stage at 500oC for 45 minutes as the second stage. The precursor material with the impregnation agent was exposed straightaway to semi-carbonization and activation temperature unlike the specific temperature progression as reported in the literature. All experiments were conducted in a laboratory scale muffle furnace under static conditions in a self generated atmosphere covering process parameters such as impregnation ratios. We found that by using this method, the AC5 had the highest iodine number and methylene blue adsorption capacity which was 506.6 mg/g and 319.0 mg/g respectively.

  10. Neural mechanisms of human perceptual learning: electrophysiological evidence for a two-stage process.

    Science.gov (United States)

    Hamamé, Carlos M; Cosmelli, Diego; Henriquez, Rodrigo; Aboitiz, Francisco

    2011-04-26

    Humans and other animals change the way they perceive the world due to experience. This process has been labeled as perceptual learning, and implies that adult nervous systems can adaptively modify the way in which they process sensory stimulation. However, the mechanisms by which the brain modifies this capacity have not been sufficiently analyzed. We studied the neural mechanisms of human perceptual learning by combining electroencephalographic (EEG) recordings of brain activity and the assessment of psychophysical performance during training in a visual search task. All participants improved their perceptual performance as reflected by an increase in sensitivity (d') and a decrease in reaction time. The EEG signal was acquired throughout the entire experiment revealing amplitude increments, specific and unspecific to the trained stimulus, in event-related potential (ERP) components N2pc and P3 respectively. P3 unspecific modification can be related to context or task-based learning, while N2pc may be reflecting a more specific attentional-related boosting of target detection. Moreover, bell and U-shaped profiles of oscillatory brain activity in gamma (30-60 Hz) and alpha (8-14 Hz) frequency bands may suggest the existence of two phases for learning acquisition, which can be understood as distinctive optimization mechanisms in stimulus processing. We conclude that there are reorganizations in several neural processes that contribute differently to perceptual learning in a visual search task. We propose an integrative model of neural activity reorganization, whereby perceptual learning takes place as a two-stage phenomenon including perceptual, attentional and contextual processes.

  11. Neural mechanisms of human perceptual learning: electrophysiological evidence for a two-stage process.

    Directory of Open Access Journals (Sweden)

    Carlos M Hamamé

    Full Text Available BACKGROUND: Humans and other animals change the way they perceive the world due to experience. This process has been labeled as perceptual learning, and implies that adult nervous systems can adaptively modify the way in which they process sensory stimulation. However, the mechanisms by which the brain modifies this capacity have not been sufficiently analyzed. METHODOLOGY/PRINCIPAL FINDINGS: We studied the neural mechanisms of human perceptual learning by combining electroencephalographic (EEG recordings of brain activity and the assessment of psychophysical performance during training in a visual search task. All participants improved their perceptual performance as reflected by an increase in sensitivity (d' and a decrease in reaction time. The EEG signal was acquired throughout the entire experiment revealing amplitude increments, specific and unspecific to the trained stimulus, in event-related potential (ERP components N2pc and P3 respectively. P3 unspecific modification can be related to context or task-based learning, while N2pc may be reflecting a more specific attentional-related boosting of target detection. Moreover, bell and U-shaped profiles of oscillatory brain activity in gamma (30-60 Hz and alpha (8-14 Hz frequency bands may suggest the existence of two phases for learning acquisition, which can be understood as distinctive optimization mechanisms in stimulus processing. CONCLUSIONS/SIGNIFICANCE: We conclude that there are reorganizations in several neural processes that contribute differently to perceptual learning in a visual search task. We propose an integrative model of neural activity reorganization, whereby perceptual learning takes place as a two-stage phenomenon including perceptual, attentional and contextual processes.

  12. Integration of a Water Scrubbing Technique and Two-Stage Pressurized Anaerobic Digestion in One Process

    Directory of Open Access Journals (Sweden)

    Andreas Lemmer

    2015-03-01

    Full Text Available Two-stage pressurized anaerobic digestion is a promising technology. This technology integrates in one process biogas production with upgrading and pressure boosting for grid injection. To investigate whether the efficiency of this novel system could be further increased, a water scrubbing system was integrated into the methanogensis step. Therefore, six leach-bed reactors were used for hydrolysis/acidification and a 30-L pressurized anaerobic filter operated at 9 bar was adopted for acetogenesis/methanogenesis. The fermentation liquid of the pressurized anaerobic filter was circulated periodically via a flash tank, operating at atmospheric pressure. Due to the pressure drop, part of dissolved carbon dioxide was released from the liquid phase into the flash tank. The depressurized fermentation liquid was then recycled to the pressurized reactor. Three different flow rates (0 L·day−1, 20 L·day−1 and 40 L·day−1 were tested with three repetitions. As the daily recycled flashed liquid flow was increased from 0 to 40 L, six times as much as the daily feeding, the methane content in the biogas increased from 75 molar percent (mol% to 87 mol%. The pH value of the substrate in the methane reactor rose simultaneously from 6.5 to 6.7. The experimental data were verified by calculation.

  13. Operation of a two-stage fermentation process producing hydrogen and methane from organic waste.

    Science.gov (United States)

    Ueno, Yoshiyuki; Fukui, Hisatomo; Goto, Masafumi

    2007-02-15

    A pilot-scale experimental plant for the production of hydrogen and methane by a two-stage fermentation process was constructed and operated using a mixture of pulverized garbage and shredded paper wastes. Thermophilic hydrogen fermentation was established at 60 degrees C in the first bioreactor by inoculating with seed microflora. Following the hydrogenogenic process, methanogenesis in the second bioreactor was conducted at 55 degrees C using an internal recirculation packed-bed reactor (IRPR). After conducting steady-state operations under a few selected conditions, the overall hydraulic retention time was optimized at 8 d (hydrogenogenesis, 1.2 d; methanogenesis, 6.8 d), producing 5.4 m3/m3/d of hydrogen and 6.1 m3/m3/d of methane with chemical oxygen demand and volatile suspended solid removal efficiencies of 79.3% and 87.8%, respectively. Maximum hydrogen production yield was calculated to be 2.4 mol/mol hexose and 56 L/kg COD loaded. The methanogenic performance of the IRPR was stable, although the organic loading rate and the composition of the effluent from the hydrogenogenic process fluctuated substantially. A clone library analysis of the microflora in the hydrogenogenic reactor indicated that hydrogen-producing Thermoanaerobacterium-related organisms in the inoculum were active in the hydrogen fermentation of garbage and paper wastes, although no aseptic operations were applied. We speculate that the operation at high temperature and the inoculation of thermophiles enabled the selective growth of the introduced microorganisms and gave hydrogen fermentation efficiencies comparable to laboratory experiments. This is the first report on fermentative production of hydrogen and methane from organic waste at an actual level.

  14. Biotransformation of Domestic Wastewater Treatment Plant Sludge by Two-Stage Integrated Processes -Lsb & Ssb

    Directory of Open Access Journals (Sweden)

    Md. Zahangir Alam, A. H. Molla and A. Fakhru’l-Razi

    2012-10-01

    Full Text Available The study of biotransformation of domestic wastewater treatment plant (DWTP sludge was conducted in laboratory-scale by two-stage integrated process i.e. liquid state bioconversion (LSB and solid state bioconversion (SSB processes. The liquid wastewater sludge [4% w/w of total suspended solids (TSS] was treated by mixed filamentous fungi Penicillium corylophilum and Aspergillus niger, isolated, screened and mixed cultured in terms of their higher biodegradation potential to wastewater sludge. The biosolids was increased to about 10% w/w. Conversely, the soluble [i.e. Total dissolve solid (TDS] and insoluble substances (TSS in treated supernatant were decreased effectively in the LSB process. In the developed LSB process, 93.8 g kg-1of biosolids were enriched with fungal biomass protein and nutrients (NPK, and 98.8% of TSS, 98.2% of TDS, 97.3% of turbidity, 80.2% of soluble protein, 98.8% of reducing sugar and 92.7% of chemical oxygen demand (COD in treated sludge supernatant were removed after 8 days of treatment. Specific resistance to filtration (1.39x1012 m/kg was decreased tremendously by the microbial treatment of DWTP sludge after 6 days of fermentation. The treated biosolids in DWTP sludge was considered as pretreated resource materials for composting and converted into compost by SSB process. The SSB process was evaluated for composting by monitoring the microbial growth and its subsequent roles in biodegradation in composting bin (CB. The process was conducted using two mixed fungal cultures, Trichoderma harzianum with Phanerochaete chrysosporium 2094 and (T/P and T. harzianum and Mucor hiemalis (T/M; and two bulking materials, sawdust (SD and rice straw (RS. The most encouraging results of microbial growth and subsequent solid state bioconversion were exhibited in the RS than the SD. Significant decrease of the C/N ratio and germination index (GI were attained as well as the higher value of glucosamine was exhibited in compost; which

  15. Methane production from sweet sorghum residues via a two-stage process

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelatou, K.; Dravillas, K.; Lyberatos, G. [University of Patras (Greece). Department of Chemical Engineering, Laboratory of Biochemical Engineering and Environmental Technology

    2003-07-01

    The start-up of a two-stage reactor configuration for the anaerobic digestion of sweet sorghum residues was evaluated. The sweet sorghum residues were a waste stream originating from the alcoholic fermentation of sweet sorghum and the subsequent distillation step. This waste stream contained high concentration of solid matter (9% TS) and thus could be characterized as a semi-solid, not easily biodegradable wastewater with high COD (115 g/l). The application of the proposed two-stage configuration (consisting of one thermophilic hydrolyser and one mesophilic methaniser) achieved a methane production of 16 l/l wastewater under a hydraulic retention time of 19 d. (author)

  16. Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process.

    Science.gov (United States)

    Luo, Gang; Xie, Li; Zhou, Qi; Angelidaki, Irini

    2011-09-01

    The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single-stage methanogenic process (HRT 15 d) under organic loading rate (OLR) 3 gVS/(L d). The two-stage process was still stable when the OLR was increased to 4.5 gVS/(Ld), while the single-stage process failed. The study further revealed that by changing the HRT(hydrogen):HRT(methane) ratio of the two-stage process from 3:12 to 1:14, 6.7%, more energy could be obtained. Microbial community analysis indicated that the dominant bacterial species were different in the hydrogen reactors (Thermoanaerobacterium thermosaccharolyticum-like species) and methane reactors (Clostridium thermocellum-like species). The changes of substrates and HRT did not change the dominant species. The archaeal community structures in methane reactors were similar both in single- and two- stage reactors, with acetoclastic methanogens Methanosarcina acetivorans-like organisms as the dominant species.

  17. Effect of two-stage coagulant addition on coagulation-ultrafiltration process for treatment of humic-rich water.

    Science.gov (United States)

    Liu, Ting; Chen, Zhong-lin; Yu, Wen-zheng; Shen, Ji-min; Gregory, John

    2011-08-01

    A novel two-stage coagulant addition strategy applied in a coagulation-ultrafiltration (UF) process for treatment of humic-rich water at neutral pH was investigated in this study. When aluminum sulfate (alum) doses were set at a ratio of 3:1 added during rapid mix stage and half way through flocculation stage, the integrated process of two-stage alum addition achieved almost the same organic matter removal as that of conventional one-stage alum addition at the same overall dose. Whereas membrane fouling could be effectively mitigated by the two-stage addition exhibited by trans-membrane pressure (TMP) developments. The TMP developments were found to be primarily attributed to external fouling on membrane surface, which was closely associated with floc characteristics. The results of jar tests indicated that the average size of flocs formed in two-stage addition mode roughly reached one half larger than that in one-stage addition mode, which implied a beneficial effect on membrane fouling reduction. Moreover, the flocs with more irregular structure and lower effective density resulted from the two-stage alum addition, which caused higher porosity of cake layer formed by such flocs on membrane surface. Microscopic observations of membrane surface demonstrated that internal fouling in membrane pores could be also remarkably limited by two-stage alum addition. It is likely that the freshly formed hydroxide precipitates were distinct in surface characteristics from the aged precipitates due to formation of more active groups or adsorption of more labile aluminum species. Consequently, the flocs could further connect and aggregate to contribute to preferable properties for filtration performance of the coagulation-UF process. As a simple and efficient approach, two-stage coagulant addition strategy could have great practical significance in coagulation-membrane processes.

  18. Two-stage, self-cycling process for the production of bacteriophages

    Directory of Open Access Journals (Sweden)

    Cooper David G

    2010-11-01

    Full Text Available Abstract Background A two-stage, self-cycling process for the production of bacteriophages was developed. The first stage, containing only the uninfected host bacterium, was operated under self-cycling fermentation (SCF conditions. This automated method, using the derivative of the carbon dioxide evolution rate (CER as the control parameter, led to the synchronization of the host bacterium. The second stage, containing both the host and the phage, was operated using self-cycling infection (SCI with CER and CER-derived data as the control parameters. When each infection cycle was terminated, phages were harvested and a new infection cycle was initiated by adding host cells from the SCF (first stage. This was augmented with fresh medium and the small amount of phages left from the previous cycle initiated the next infection cycle. Both stages were operated independently, except for this short period of time when the SCF harvest was added to the SCI to initiate the next cycle. Results It was demonstrated that this mode of operation resulted in stable infection cycles if the growth of the host cells in the SCF was synchronized. The final phage titers obtained were reproducible among cycles and were as good as those obtained in batch productions performed under the same conditions (medium, temperature, initial multiplicity of infection, etc.. Moreover, phages obtained in different cycles showed no important difference in infectivity. Finally, it was shown that cell synchronization of the host cells in the first stage (SCF not only maintained the volumetric productivity (phages per volume but also led to higher specific productivity (phage per cell per hour in the second stage (SCI. Conclusions Production of bacteriophage T4 in the semi-continuous, automated SCF/SCI system was efficient and reproducible from cycle to cycle. Synchronization of the host in the first stage prior to infection led to improvements in the specific productivity of phages in

  19. Synthetic control charts with two-stage sampling for monitoring bivariate processes

    Directory of Open Access Journals (Sweden)

    Antonio F. B. Costa

    2007-04-01

    Full Text Available In this article, we consider the synthetic control chart with two-stage sampling (SyTS chart to control bivariate processes. During the first stage, one item of the sample is inspected and two correlated quality characteristics (x;y are measured. If the Hotelling statistic T1² for these individual observations of (x;y is lower than a specified value UCL1 the sampling is interrupted. Otherwise, the sampling goes on to the second stage, where the remaining items are inspected and the Hotelling statistic T2² for the sample means of (x;y is computed. When the statistic T2² is larger than a specified value UCL2, the sample is classified as nonconforming. According to the synthetic control chart procedure, the signal is based on the number of conforming samples between two neighbor nonconforming samples. The proposed chart detects process disturbances faster than the bivariate charts with variable sample size and it is from the practical viewpoint more convenient to administer.Este artigo apresenta um gráfico de controle com regra especial de decisão e amostragens em dois estágios para o monitoramento de processos bivariados. No primeiro estágio, um item da amostra é inspecionado e duas características de qualidade correlacionadas (x;y são medidas. Se a estatística de Hotelling T1² para as observações individuais de (x;y for menor que um valor especificado UCL1 a amostragem é interrompida. Caso contrário, a amostragem segue para o segundo estágio, onde os demais itens da amostra são inspecionados e a estatística de Hotelling T2² para as médias de (x;y é calculada. Quando a estatística T2² é maior que um valor especificado UCL2, a amostra é classificada como não conforme. De acordo com a regra especial de decisão, o alarme é baseado no número de amostras entre duas não conformes. O gráfico proposto é mais ágil e mais simples do ponto de vista operacional que o gráfico de controle bivariado com tamanho de amostras variável.

  20. Influence of bulking agents on physical, chemical, and microbiological properties during the two-stage composting of green waste.

    Science.gov (United States)

    Zhang, Lu; Sun, Xiangyang

    2016-02-01

    A recyclable organic bulking agent (BA) that can be screened and was developed to optimize green waste (GW) composting. This study investigated the use of wood chips (WC) (at 0%, 15%, and 25%) and/or composted green waste (CGW) (at 0%, 25%, and 35%) as the BAs in the two-stage composting of GW. The combined addition of WC and CGW improved the conditions of composting process and the quality of compost product in terms of composting temperature, porosity, water retention, particle-size distribution, pH, electrical conductivity (EC), cation exchange capacity (CEC), nitrogen losses, humification indices, microbial numbers, enzyme activities, macro- and micro-nutrient contents, and toxicity to germinating seeds. The compost matured in only 22days with the optimized two-stage composting method rather than in the 90-270days typically required for traditional composting. The optimal two-stage composting process and the best quality of compost product were obtained with the combined addition of 15% WC and 35% CGW.

  1. Biomass waste gasification - can be the two stage process suitable for tar reduction and power generation?

    Science.gov (United States)

    Sulc, Jindřich; Stojdl, Jiří; Richter, Miroslav; Popelka, Jan; Svoboda, Karel; Smetana, Jiří; Vacek, Jiří; Skoblja, Siarhei; Buryan, Petr

    2012-04-01

    A pilot scale gasification unit with novel co-current, updraft arrangement in the first stage and counter-current downdraft in the second stage was developed and exploited for studying effects of two stage gasification in comparison with one stage gasification of biomass (wood pellets) on fuel gas composition and attainable gas purity. Significant producer gas parameters (gas composition, heating value, content of tar compounds, content of inorganic gas impurities) were compared for the two stage and the one stage method of the gasification arrangement with only the upward moving bed (co-current updraft). The main novel features of the gasifier conception include grate-less reactor, upward moving bed of biomass particles (e.g. pellets) by means of a screw elevator with changeable rotational speed and gradual expanding diameter of the cylindrical reactor in the part above the upper end of the screw. The gasifier concept and arrangement are considered convenient for thermal power range 100-350 kW(th). The second stage of the gasifier served mainly for tar compounds destruction/reforming by increased temperature (around 950°C) and for gasification reaction of the fuel gas with char. The second stage used additional combustion of the fuel gas by preheated secondary air for attaining higher temperature and faster gasification of the remaining char from the first stage. The measurements of gas composition and tar compound contents confirmed superiority of the two stage gasification system, drastic decrease of aromatic compounds with two and higher number of benzene rings by 1-2 orders. On the other hand the two stage gasification (with overall ER=0.71) led to substantial reduction of gas heating value (LHV=3.15 MJ/Nm(3)), elevation of gas volume and increase of nitrogen content in fuel gas. The increased temperature (>950°C) at the entrance to the char bed caused also substantial decrease of ammonia content in fuel gas. The char with higher content of ash leaving the

  2. Enhanced biodiesel production in Neochloris oleoabundans by a semi-continuous process in two stage photobioreactors.

    Science.gov (United States)

    Yoon, Se Young; Hong, Min Eui; Chang, Won Seok; Sim, Sang Jun

    2015-07-01

    Under autotrophic conditions, highly productive biodiesel production was achieved using a semi-continuous culture system in Neochloris oleoabundans. In particular, the flue gas generated by combustion of liquefied natural gas and natural solar radiation were used for cost-effective microalgal culture system. In semi-continuous culture, the greater part (~80%) of the culture volume containing vegetative cells grown under nitrogen-replete conditions in a first photobioreactor (PBR) was directly transferred to a second PBR and cultured sequentially under nitrogen-deplete conditions for accelerating oil accumulation. As a result, in semi-continuous culture, the productivities of biomass and biodiesel in the cells were increased by 58% (growth phase) and 51% (induction phase) compared to the cells in batch culture, respectively. The semi-continuous culture system using two stage photobioreactors is a very efficient strategy to further improve biodiesel production from microalgae under photoautotrophic conditions.

  3. Operation of a two-stage continuous fermentation process producing hydrogen and methane from artificial food wastes

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Kohki; Mizuno, Shiho; Umeda, Yoshito; Sakka, Makiko [Toho Gas Co., Ltd. (Japan); Osaka, Noriko [Tokyo Gas Co. Ltd. (Japan); Sakka, Kazuo [Mie Univ. (Japan)

    2010-07-01

    An anaerobic two-stage continuous fermentation process with combined thermophilic hydrogenogenic and methanogenic stages (two-stage fermentation process) was applied to artificial food wastes on a laboratory scale. In this report, organic loading rate (OLR) conditions for hydrogen fermentation were optimized before operating the two-stage fermentation process. The OLR was set at 11.2, 24.3, 35.2, 45.6, 56.1, and 67.3 g-COD{sub cr} L{sup -1} day{sup -1} with a temperature of 60 C, pH5.5 and 5.0% total solids. As a result, approximately 1.8-2.0 mol-H{sub 2} mol-hexose{sup -1} was obtained at the OLR of 11.2-56.1 g-COD{sub cr} L{sup -1} day{sup -1}. In contrast, it was inferred that the hydrogen yield at the OLR of 67.3 g-COD{sub cr} L{sup -1} day{sup -1} decreased because of an increase in lactate concentration in the culture medium. The performance of the two-stage fermentation process was also evaluated over three months. The hydraulic retention time (HRT) of methane fermentation was able to be shortened 5.0 days (under OLR 12.4 g-COD{sub cr} L{sup -1} day{sup -1} conditions) when the OLR of hydrogen fermentation was 44.0 g-COD{sub cr} L{sup -1} day{sup -1}, and the average gasification efficiency of the two-stage fermentation process was 81% at the time. (orig.)

  4. An evaluation of a two-stage spiral processing ultrafine bituminous coal

    Energy Technology Data Exchange (ETDEWEB)

    Matthew D. Benusa; Mark S. Klima [Penn State University, University Park, PA (United States). Energy and Mineral Engineering

    2008-10-15

    Testing was conducted to evaluate the performance of a multistage Multotec SX7 spiral concentrator treating ultrafine bituminous coal. This spiral mimics a two-stage separation in that the refuse is removed after four turns, and the clean coal and middlings are repulped (without water addition) and then separated in the final three turns. Feed samples were collected from the spiral circuit of a coal cleaning plant located in southwestern Pennsylvania. The samples consisted of undeslimed cyclone feed (nominal -0.15 mm) and deslimed spiral feed (nominal 0.15 x 0.053 mm). Testing was carried out to investigate the effects of slurry flow rate and solids concentration on spiral performance. Detailed size and ash analyses were performed on the spiral feed and product samples. For selected tests, float-sink and sulfur analyses were performed. In nearly all cases, ash reduction occurred down to approximately 0.025 mm, with some sulfur reduction occurring even in the -0.025 mm interval. The separation of the +0.025 mm material was not significantly affected by the presence of the -0.025 mm material when treating the undeslimed feed. The -0.025 mm material split in approximately the same ratio as the slurry, and the majority of the water traveled to the clean coal stream. This split ultimately increased the overall clean coal ash value. A statistical analysis determined that both flow rate and solids concentration affected the clean coal ash value and yield, though the flow rate had a greater effect on the separation. 23 refs.

  5. A two-stage process for the anaerobic digestion of sludge generated during the production of bioethanol from sweet sorghum

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelatou, K.; Dravillas, K.; Lyberatos, G.

    2003-07-01

    Sweet sorghum is an energy crop, often cultivated to recover energy in the form of ethanol, hydrogen etc by applying biological processes. These processes, however, produce a significant amount of sludge (bagasse) which contains the recalcitrant unconverted portion of sorghum, the non-hydrolyzed portion of the plant biomass as well as microbial biomass. In this work, the sludge from the alcoholic fermentation of sweet sorghum following a distillation step (to remove the generated bioethanol) was subjected to anaerobic digestion for further biodegradation and energy production (methane). A two-stage configuration for the anaerobic digestion of this type of industrial sludge was conceived and compared with a single stage anaerobic digestion of bagasse. For the two-stage process, the sludge was separated into one solid and one liquid stream. The solid portion of the sludge (9%) contributed mainly to the total organic load, although there was a significant organic load dissolved in the liquid portion too (28.73{+-}11.01 g/l). In the two stage system the solid and liquid phases of the sludge were separately treated under different operating conditions in two separate reactors: the solid phase in a thermophilic hydrolyzing reactor and the liquid phase in a mesophilic high-rate digester. The overall yield of the continuous two-stage process was 16 l methane/l wastewater at a hydraulic retention time of almost 20 days, while the maximum methane yield that could be achieved in batch experiments (duration 40d) was 30 l/l wastewater. (author)

  6. Evaluation of aeration pretreatment to prepare an inoculum for the two-stage hydrogen and methane production process.

    Science.gov (United States)

    Giordano, Andrea; Sarli, Valentina; Lavagnolo, Maria Cristina; Spagni, Alessandro

    2014-08-01

    This study evaluates the effect of aeration pretreatment to prepare an inoculum for H₂ and CH₄ production in a two-stage process. Moreover, the biochemical hydrogen potential and biochemical methane potential of waste from the food industry in a two-stage process was assessed. The results confirmed the possibility of using an aerobic stress for selecting a hydrogen-producing inoculum. The inoculum was fairly stable since no hydrogenotrophic-methanogenic activity was observed in 25 days. The yields measured using glucose as substrate were of approximately 160 and 280 N mL(H₂) g(COD⁻¹) of glucose for hydrogen and methane, respectively, which are in agreement with other studies using heat-shock for the pretreatment of the inoculum. When waste of the food industry (wheat milling) was used as substrate, a lower H₂ yield was achieved by the aerobically-pretreated inoculum if compared to heat-shock; however, when combined with methane production in a two-stage process, much higher CH₄ yield was achieved.

  7. Two-stage pervaporation process for effective in situ removal acetone-butanol-ethanol from fermentation broth.

    Science.gov (United States)

    Cai, Di; Hu, Song; Miao, Qi; Chen, Changjing; Chen, Huidong; Zhang, Changwei; Li, Ping; Qin, Peiyong; Tan, Tianwei

    2017-01-01

    Two-stage pervaporation for ABE recovery from fermentation broth was studied to reduce the energy cost. The permeate after the first stage in situ pervaporation system was further used as the feedstock in the second stage of pervaporation unit using the same PDMS/PVDF membrane. A total 782.5g/L of ABE (304.56g/L of acetone, 451.98g/L of butanol and 25.97g/L of ethanol) was achieved in the second stage permeate, while the overall acetone, butanol and ethanol separation factors were: 70.7-89.73, 70.48-84.74 and 9.05-13.58, respectively. Furthermore, the theoretical evaporation energy requirement for ABE separation in the consolidate fermentation, which containing two-stage pervaporation and the following distillation process, was estimated less than ∼13.2MJ/kg-butanol. The required evaporation energy was only 36.7% of the energy content of butanol. The novel two-stage pervaporation process was effective in increasing ABE production and reducing energy consumption of the solvents separation system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Fuzzy self-tuning PID control of the operation temperatures in a two-staged membrane separation process

    Institute of Scientific and Technical Information of China (English)

    Lei Wang; Wencai Du; Hai Wang; Hong Wu

    2008-01-01

    A two-staged membrane separation process for hydrogen recovery from refinery gases is introduced. The principle of the gas membrane separation process and the influence of the operation temperatures are analyzed. As the conventional PID controller is difficult to make the operation temperatures steady, a fuzzy self-tuning PID control algorithm is proposed. The application shows that the algorithm is effective, the operation temperatures of both stages can be controlled steadily, and the operation flexibility and adaptability of the hydrogen recovery unit are enhanced with safety. This study lays a foundation to optimize the control of the membrane separation process and thus ensure the membrane performance.

  9. Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process

    DEFF Research Database (Denmark)

    Lehtinen, Tapio; Efimova, Elena; Tremblay, Pier-Luc

    2017-01-01

    Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long...... in an aerobic bioprocess. In this proof-of-principle study, we demonstrate for the first time the bacterial production of long alkyl esters (wax esters) from carbon dioxide and electricity as the sole sources of carbon and energy. The process holds potential for the efficient production of carbon...

  10. HOSPITAL SITE SELECTION USING TWO-STAGE FUZZY MULTI-CRITERIA DECISION MAKING PROCESS

    Directory of Open Access Journals (Sweden)

    Ali Soltani

    2011-01-01

    Full Text Available Site selection for sitting of urban activities/facilities is one of the crucial policy-related decisions taken by urban planners and policy makers. The process of site selection is inherently complicated. A careless site imposes exorbitant costs on city budget and damages the environment inevitably. Nowadays, multi-attributes decision making approaches are suggested to use to improve precision of decision making and reduce surplus side effects. Two well-known techniques, analytical hierarchal process and analytical network process are among multi-criteria decision making systems which can easily be consistent with both quantitative and qualitative criteria. These are also developed to be fuzzy analytical hierarchal process and fuzzy analytical network process systems which are capable of accommodating inherent uncertainty and vagueness in multi-criteria decision-making. This paper reports the process and results of a hospital site selection within the Region 5 of Shiraz metropolitan area, Iran using integrated fuzzy analytical network process systems with Geographic Information System (GIS. The weights of the alternatives were calculated using fuzzy analytical network process. Then a sensitivity analysis was conducted to measure the elasticity of a decision in regards to different criteria. This study contributes to planning practice by suggesting a more comprehensive decision making tool for site selection.

  11. HOSPITAL SITE SELECTION USING TWO-STAGE FUZZY MULTI-CRITERIA DECISION MAKING PROCESS

    Directory of Open Access Journals (Sweden)

    Ali Soltani

    2011-06-01

    Full Text Available Site selection for sitting of urban activities/facilities is one of the crucial policy-related decisions taken by urban planners and policy makers. The process of site selection is inherently complicated. A careless site imposes exorbitant costs on city budget and damages the environment inevitably. Nowadays, multi-attributes decision making approaches are suggested to use to improve precision of decision making and reduce surplus side effects. Two well-known techniques, analytical hierarchal process and analytical network process are among multi-criteria decision making systems which can easily be consistent with both quantitative and qualitative criteria. These are also developed to be fuzzy analytical hierarchal process and fuzzy analytical network process systems which are capable of accommodating inherent uncertainty and vagueness in multi-criteria decision-making. This paper reports the process and results of a hospital site selection within the Region 5 of Shiraz metropolitan area, Iran using integrated fuzzy analytical network process systems with Geographic Information System (GIS. The weights of the alternatives were calculated using fuzzy analytical network process. Then a sensitivity analysis was conducted to measure the elasticity of a decision in regards to different criteria. This study contributes to planning practice by suggesting a more comprehensive decision making tool for site selection.

  12. Enhancing the hydrolysis process of a two-stage biogas technology for the organic fraction of municipal solid waste

    DEFF Research Database (Denmark)

    Nasir, Zeeshan; Uellendahl, Hinrich

    2015-01-01

    The Danish company Solum A/S has developed a two-stage dry anaerobic digestion process labelled AIKAN® for the biological conversion of the organic fraction of municipal solid waste (OFMSW) into biogas and compost. In the AIKAN® process design the methanogenic (2nd) stage is separated from...... time, recirculation rate of percolate, ratio of admixing effluent from the anaerobic stage to the percolate, water submerge of waste) on the efficiency of the hydrolytic stage. •The effect of addition of adapted mixed cultures and specific hydrolytic microorganisms on the hydrolysis of the waste. •The...

  13. Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

    KAUST Repository

    Alfazazi, Adamu

    2016-08-10

    The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate the ignition delay of n-dodecane and n-heptane in a constant volume combustion chamber (CVCC), which is archived in the engine combustion network (ECN) library (http://www.ca.sandia.gov/ecn). A detailed chemical kinetic model for gasoline surrogates from the Lawrence Livermore National Laboratory (LLNL) was utilized for the simulation of n-heptane and isooctane. Additional simulations were performed using an optimized gasoline surrogate mechanism from RWTH Aachen University. Validations of the simulated data were also performed with experimental results from an IQT at KAUST. For simulation of n-dodecane in the CVCC, two n-dodecane kinetic models from the literature were utilized. The primary aim of this study is to test the ability of TSL to replicate ignition timings in the IQT and the CVCC. The agreement between the model and the experiment is acceptable except for isooctane in the IQT and n-heptane and n-dodecane in the CVCC. The ability of the simulations to replicate observable trends in ignition delay times with regard to changes in ambient temperature and pressure allows the model to provide insights into the reactions contributing towards ignition. Thus, the TSL model was further employed to investigate the physical and chemical processes responsible for controlling the overall ignition under various conditions. The effects of exothermicity, ambient pressure, and ambient oxygen concentration on first stage ignition were also studied. Increasing ambient pressure and oxygen concentration was found to shorten the overall ignition delay time, but does not affect the timing of the first stage ignition. Additionally, the temperature at the end of the first stage ignition was found to increase at higher ambient pressure

  14. A Two-Stage Process Model of Sensory Discrimination: An Alternative to Drift-Diffusion.

    Science.gov (United States)

    Sun, Peng; Landy, Michael S

    2016-11-02

    Discrimination of the direction of motion of a noisy stimulus is an example of sensory discrimination under uncertainty. For stimuli that are extended in time, reaction time is quicker for larger signal values (e.g., discrimination of opposite directions of motion compared with neighboring orientations) and larger signal strength (e.g., stimuli with higher contrast or motion coherence, that is, lower noise). The standard model of neural responses (e.g., in lateral intraparietal cortex) and reaction time for discrimination is drift-diffusion. This model makes two clear predictions. (1) The effects of signal strength and value on reaction time should interact multiplicatively because the diffusion process depends on the signal-to-noise ratio. (2) If the diffusion process is interrupted, as in a cued-response task, the time to decision after the cue should be independent of the strength of accumulated sensory evidence. In two experiments with human participants, we show that neither prediction holds. A simple alternative model is developed that is consistent with the results. In this estimate-then-decide model, evidence is accumulated until estimation precision reaches a threshold value. Then, a decision is made with duration that depends on the signal-to-noise ratio achieved by the first stage. Sensory decision-making under uncertainty is usually modeled as the slow accumulation of noisy sensory evidence until a threshold amount of evidence supporting one of the possible decision outcomes is reached. Furthermore, it has been suggested that this accumulation process is reflected in neural responses, e.g., in lateral intraparietal cortex. We derive two behavioral predictions of this model and show that neither prediction holds. We introduce a simple alternative model in which evidence is accumulated until a sufficiently precise estimate of the stimulus is achieved, and then that estimate is used to guide the discrimination decision. This model is consistent with the

  15. Preliminary chemical analysis and biological testing of materials from the HRI catalytic two-stage liquefaction (CTSL) process. [Aliphatic hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Later, D.W.; Wilson, B.W.

    1985-01-01

    Coal-derived materials from experimental runs of Hydrocarbon Research Incorporated's (HRI) catalytic two-stage liquefaction (CTSL) process were chemically characterized and screened for microbial mutagenicity. This process differs from two-stage coal liquefaction processes in that catalyst is used in both stages. Samples from both the first and second stages were class-fractionated by alumina adsorption chromatography. The fractions were analyzed by capillary column gas chromatography; gas chromatography/mass spectrometry; direct probe, low voltage mass spectrometry; and proton nuclear magnetic resonance spectrometry. Mutagenicity assays were performed with the crude and class fractions in Salmonella typhimurium, TA98. Preliminary results of chemical analyses indicate that >80% CTSL materials from both process stages were aliphatic hydrocarbon and polynuclear aromatic hydrocarbon (PAH) compounds. Furthermore, the gross and specific chemical composition of process materials from the first stage were very similar to those of the second stage. In general, the unfractionated materials were only slightly active in the TA98 mutagenicity assay. Like other coal liquefaction materials investigated in this laboratory, the nitrogen-containing polycyclic aromatic compound (N-PAC) class fractions were responsible for the bulk of the mutagenic activity of the crudes. Finally, it was shown that this activity correlated with the presence of amino-PAH. 20 figures, 9 tables.

  16. A novel two-stage MBR denitrification process for the treatment of high strength pet food wastewater.

    Science.gov (United States)

    Acharya, C; Nakhla, G; Bassi, A

    2006-02-28

    A novel paradigm using pre-denitrification process is presented to optimize an existing system of two-stage MBRs treating high strength pet food wastewater. Successive reduction of organics in the 1st stage and almost complete nitrification in the 2nd stage generated effluent meeting stringent surface discharge criteria i.e. BOD5, TSS and NH4+ -N of recycle ratio of 3:1, total nitrogen was reduced by 84%, aeration energy by 25% and the external alkalinity requirement by 65%, enhancing economical viability of the system.

  17. Production of long chain alkyl esters from carbon dioxide and electricity by a two-stage bacterial process.

    Science.gov (United States)

    Lehtinen, Tapio; Efimova, Elena; Tremblay, Pier-Luc; Santala, Suvi; Zhang, Tian; Santala, Ville

    2017-11-01

    Microbial electrosynthesis (MES) is a promising technology for the reduction of carbon dioxide into value-added multicarbon molecules. In order to broaden the product profile of MES processes, we developed a two-stage process for microbial conversion of carbon dioxide and electricity into long chain alkyl esters. In the first stage, the carbon dioxide is reduced to organic compounds, mainly acetate, in a MES process by Sporomusa ovata. In the second stage, the liquid end-products of the MES process are converted to the final product by a second microorganism, Acinetobacter baylyi in an aerobic bioprocess. In this proof-of-principle study, we demonstrate for the first time the bacterial production of long alkyl esters (wax esters) from carbon dioxide and electricity as the sole sources of carbon and energy. The process holds potential for the efficient production of carbon-neutral chemicals or biofuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. ADM1-based modeling of methane production from acidified sweet sorghum extract in a two stage process.

    Science.gov (United States)

    Antonopoulou, Georgia; Gavala, Hariklia N; Skiadas, Ioannis V; Lyberatos, Gerasimos

    2012-02-01

    The present study focused on the application of the Anaerobic Digestion Model 1 on the methane production from acidified sorghum extract generated from a hydrogen producing bioreactor in a two-stage anaerobic process. The kinetic parameters for hydrogen and volatile fatty acids consumption were estimated through fitting of the model equations to the data obtained from batch experiments. The simulation of the continuous reactor performance at all HRTs tested (20, 15, and 10d) was very satisfactory. Specifically, the largest deviation of the theoretical predictions against the experimental data was 12% for the methane production rate at the HRT of 20d while the deviation values for the 15 and 10d HRT were 1.9% and 1.1%, respectively. The model predictions regarding pH, methane percentage in the gas phase and COD removal were in very good agreement with the experimental data with a deviation less than 5% for all steady states. Therefore, the ADM1 is a valuable tool for process design in the case of a two-stage anaerobic process as well.

  19. Enhancing the hydrolysis process of a two-stage biogas technology for the organic fraction of municipal solid waste

    DEFF Research Database (Denmark)

    Nasir, Zeeshan; Uellendahl, Hinrich

    2015-01-01

    the hydrolytic (1st) stage, which enables pump-free feeding of the waste into the 1st stage (processing module), and eliminates the risk for blocking of pumps and pipes by pumping only the percolate from the 1st stage into the 2nd stage (biogas reactor tank). The biogas yield of the AIKAN® two-stage process...... as lab-scale batch and pilot-scale reactor tests. A lab-scale reactor system to mimic the 2-stage set-up in large-scale is currently set-up and the results will be included in the final conference paper. The first pilot-scale tests were performed at Solum’s pilot-scale modules by adjusting the p...

  20. THE MATHEMATICAL MODEL DEVELOPMENT OF THE ETHYLBENZENE DEHYDROGENATION PROCESS KINETICS IN A TWO-STAGE ADIABATIC CONTINUOUS REACTOR

    Directory of Open Access Journals (Sweden)

    V. K. Bityukov

    2015-01-01

    Full Text Available The article is devoted to the mathematical modeling of the kinetics of ethyl benzene dehydrogenation in a two-stage adiabatic reactor with a catalytic bed functioning on continuous technology. The analysis of chemical reactions taking place parallel to the main reaction of styrene formation has been carried out on the basis of which a number of assumptions were made proceeding from which a kinetic scheme describing the mechanism of the chemical reactions during the dehydrogenation process was developed. A mathematical model of the dehydrogenation process, describing the dynamics of chemical reactions taking place in each of the two stages of the reactor block at a constant temperature is developed. The estimation of the rate constants of direct and reverse reactions of each component, formation and exhaustion of the reacted mixture was made. The dynamics of the starting material concentration variations (ethyl benzene batch was obtained as well as styrene formation dynamics and all byproducts of dehydrogenation (benzene, toluene, ethylene, carbon, hydrogen, ect.. The calculated the variations of the component composition of the reaction mixture during its passage through the first and second stages of the reactor showed that the proposed mathematical description adequately reproduces the kinetics of the process under investigation. This demonstrates the advantage of the developed model, as well as loyalty to the values found for the rate constants of reactions, which enable the use of models for calculating the kinetics of ethyl benzene dehydrogenation under nonisothermal mode in order to determine the optimal temperature trajectory of the reactor operation. In the future, it will reduce energy and resource consumption, increase the volume of produced styrene and improve the economic indexes of the process.

  1. Long-term performance and microbial ecology of a two-stage PN-ANAMMOX process treating mature landfill leachate.

    Science.gov (United States)

    Li, Huosheng; Zhou, Shaoqi; Ma, Weihao; Huang, Pengfei; Huang, Guotao; Qin, Yujie; Xu, Bin; Ouyang, Hai

    2014-05-01

    Long-term performance of a two-stage partial nitritation (PN)-anaerobic ammonium oxidation (ANAMMOX) process treating mature landfill leachate was investigated. Stable partial nitritation performance was achieved in a sequencing batch reactor (SBR) using endpoint pH control, providing an effluent with a ratio of NO2(-)-N/NH4(+)-N at 1.23 ± 0.23. High rate nitrogen removal over 4 kg N/m(3)/d was observed in the ANAMMOX reactor in the first three months. However, during long-term operation, the ANAMMOX reactor can only stably operate under nitrogen load of 1 kg N/m(3)/d, with 85 ± 1% of nitrogen removal. The ammonium oxidizing bacteria (AOB) in the PN-SBR were mainly affiliated to Nitrosomonas sp. IWT514, Nitrosomonas eutropha and Nitrosomonas eutropha, the anaerobic ammonium oxidizing bacteria (AnAOB) in the ANAMMOX reactor were mainly affiliated to Kuenenia stuttgartiensis.

  2. A study of the process of two staged anaerobic fermentation as a possible method for purifying sewage

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y.; Kouama, K.; Matsuo, T.

    1983-01-01

    Great attention has recently been given to the study of the processes of anaerobic fermentation, which may become alternatives to the existing methods for purifying waste waters which use aerobic microorganisms. A series of experimentswere conducted with the use of an artificially prepared liquid (fermented milk and starch) which imitates the waste to be purified, in order to explain the capabilities of the process of two staged anaerobic fermentation (DAS) as a method for purifying waste waters. The industrial system of the process includes: a fermentation vat for acetic fermentation with recirculation of the sediment, a primary settler, a fermentation tank for methane fermentation and a secondary settler. The process was conducted at a loading speed (based on Carbon) from 0.15 to 0.4 kilograms per cubic meter per day at a temperature of 38C. The degree of conversion of the fermented organic substances into volatile organic acids was not a function of the loading speed and was 54 to 57 percent in the acetic fermentation tank, where 95 to 97 percent of the organic material was broken down with the production of methane and carbon dioxide.

  3. Mathematical modeling of a continuous alcoholic fermentation process in a two-stage tower reactor cascade with flocculating yeast recycle.

    Science.gov (United States)

    de Oliveira, Samuel Conceição; de Castro, Heizir Ferreira; Visconti, Alexandre Eliseu Stourdze; Giudici, Reinaldo

    2015-03-01

    Experiments of continuous alcoholic fermentation of sugarcane juice with flocculating yeast recycle were conducted in a system of two 0.22-L tower bioreactors in series, operated at a range of dilution rates (D 1 = D 2 = 0.27-0.95 h(-1)), constant recycle ratio (α = F R /F = 4.0) and a sugar concentration in the feed stream (S 0) around 150 g/L. The data obtained in these experimental conditions were used to adjust the parameters of a mathematical model previously developed for the single-stage process. This model considers each of the tower bioreactors as a perfectly mixed continuous reactor and the kinetics of cell growth and product formation takes into account the limitation by substrate and the inhibition by ethanol and biomass, as well as the substrate consumption for cellular maintenance. The model predictions agreed satisfactorily with the measurements taken in both stages of the cascade. The major differences with respect to the kinetic parameters previously estimated for a single-stage system were observed for the maximum specific growth rate, for the inhibition constants of cell growth and for the specific rate of substrate consumption for cell maintenance. Mathematical models were validated and used to simulate alternative operating conditions as well as to analyze the performance of the two-stage process against that of the single-stage process.

  4. Operational strategy for nitrogen removal from centrate in a two-stage partial nitrification--anammox process.

    Science.gov (United States)

    Kosari, S F; Rezania, B; Lo, K V; Mavinic, D S

    2014-01-01

    This paper presents the operational strategy for nitrogen removal in a two-stage, partial nitrification (PN) process coupled with anaerobic ammonium oxidation (Anammox) process. The process was used to remove ammonium from centrate obtained from a full-scale, wastewater treatment plant in British Columbia, Canada. The PN, which was carried out in a sequencing batch reactor (SBR), successfully converted approximately 49.5 +/- 1.0% of ammonium to nitrite. The operation of SBR under higher dissolved oxygen in combination with slow feeding resulted in significant reduced HRT without nitrate accumulation. Partially nitrified centrate was further treated in Anammox reactors, where the mixture of ammonium and nitrite was converted mainly to nitrogen gas. Anammox treatment was carried out in two different types of Anammox reactors: a moving bed hybrid reactor and an up-flow fixed-bed biofilm reactor. The hybrid Anammox reactor removed an average of 55.8% of NH4-N, versus the 48.3% NH4-N removed in the up-flow fixed-bed reactor. Nitrite removal in the hybrid and up-flow fixed-bed Anammox reactors averaged 80.8% and 62.5%, respectively. This study also illustrated that in both Anammox reactors, better ammonium removal was achieved when the nitrite to ammonium ratio is between 1.35 and 1.45. As such, alkalinity was found to neither control nor limit the Anammox reaction.

  5. USE OF GAC TECHNOLOGY AND TWO STAGE ION EXCHANGE TECHNIQUE FOR RECYCLING OF WASTEWATER IN TEXTILE WET PROCESSING

    Directory of Open Access Journals (Sweden)

    PROF. MAHESH B. CHOUGULE

    2012-01-01

    Full Text Available Water is essential natural resource for sustaining life and environment, which is always thought to be available in abundance and free gift of nature. Textile industries are one of the major consumers of water and disposing large volumes of effluent to the environment. The textile industry utilizes abundant water in dyeing and finishing processes. There is need to adopt economical practices for the use of water in textile industries. It has been estimated that 3.5 % of the total cost of running the industry is required for water utilization in textile industry. In India textile units are developed all over the country in the form of small industrial estates. Textiles are manufactured to perform a multitude of functions. They are produced to a range of specifications using avariety of fibers, resulting in a complex waste or effluent. Textile waste occurs in a variety of forms throughout production process. The surface water sources are limited and availability of water from them vary from year to year depending upon monsoon conditions. The underground water resources are also getting depleted with theincreasing amount of water drawn from them every year without adequate replenishments. Therefore, the cost of water is rising steeply and the textile mills, which need a large quantity of water, have started taking measures to conserve and recycling. This paper focuses on recycling of wastewater in textile wet processing with experimental analysis of GAC technology and two-stage ion exchange technology.

  6. Catalytic Two-Stage Liquefaction (CTSL) process bench studies with bituminous coal. Final report, [October 1, 1988--December 31, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Comolli, A.G.; Johanson, E.S.; Karolkiewicz, W.F.; Lee, L.K.; Stalzer, R.H.; Smith, T.O.

    1993-03-01

    Reported herein are the details and results of Laboratory and Bench-Scale experiments using bituminous coal concluded at Hydrocarbon Research, Inc., under DOE contract during the period October 1, 1988 to December 31, 1992. The work described is primarily concerned with the application of coal cleaning methods and solids separation methods to the Catalytic Two-Stage Liquefaction (CTSL) Process. Additionally a predispersed catalyst was evaluated in a thermal/catalytic configuration, and an alternative nickel molybdenum catalyst was evaluated for the CTSL process. Three coals were evaluated in this program: Bituminous Illinois No. 6 Burning Star and Sub-bituminous Wyoming Black Thunder and New Mexico McKinley Mine seams. The results from a total of 16 bench-scale runs are reported and analyzed in detail. The tests involving the Illinois coal are reported herein, and the tests involving the Wyoming and New Mexico coals are described in Topical Report No. 1. On the laboratory scale, microautoclave tests evaluating coal, start-up oils, catalysts, thermal treatment, CO{sub 2} addition and sulfur compound effects are reported in Topical Report No. 3. Other microautoclave tests, such as tests on rejuvenated catalyst, coker liquids, and cleaned coals, are described in the Bench Run sections to which they refer. The microautoclave tests conducted for modelling the CTSL process are described in the CTSL Modelling section of Topical Report No. 3 under this contract.

  7. A hybrid cascade control scheme for the VFA and COD regulation in two-stage anaerobic digestion processes.

    Science.gov (United States)

    Méndez-Acosta, H O; Campos-Rodríguez, A; González-Álvarez, V; García-Sandoval, J P; Snell-Castro, R; Latrille, E

    2016-10-01

    A hybrid (continuous-discrete) cascade control is proposed to regulate both, volatile fatty acids (VFA) and chemical oxygen demand (COD) concentrations in two-stage (acidogenic-methanogenic) anaerobic digestion (TSAD) processes. The outer loop is a discrete controller that regulates the COD concentration of the methanogenic bioreactor by using a daily off-line measurement and that modifies the set-point tracked by inner loop, which manipulates the dilution rate to regulate the VFA concentration of the acidogenic bioreactor, estimated by continuous on-line conductivity measurements, avoiding acidification. The experimental validation was conducted in a TSAD process for the treatment of tequila vinasses during 110days. Results showed that the proposed cascade control scheme was able to achieve the VFA and COD regulation by using conventional measurements under different set-point values in spite of adverse common scenarios in full-scale anaerobic digestion processes. Microbial composition analysis showed that the controller also favors the abundance and diversity toward methane production.

  8. Pyrolysis of Pinus pinaster in a two-stage gasifier: Influence of processing parameters and thermal cracking of tar

    Energy Technology Data Exchange (ETDEWEB)

    Fassinou, Wanignon Ferdinand; Toure, Siaka [Laboratoire d' Energie Solaire-UFR-S.S.M.T. Universite de Cocody, 22BP582 Abidjan 22 (Ivory Coast); Van de Steene, Laurent; Volle, Ghislaine; Girard, Philippe [CIRAD-Foret, TA 10/16, 73, avenue J.-F. Breton, 34398 Montpellier, Cedex 5 (France)

    2009-01-15

    A new two-stage gasifier with fixed-bed has recently been installed on CIRAD facilities in Montpellier. The pyrolysis and the gasifier units are removable. In order to characterise the pyrolysis products before their gasification, experiments were carried out, for the first time only with the pyrolysis unit and this paper deals with the results obtained. The biomass used is Pinus pinaster. The parameters investigated are: temperature, residence time and biomass flow rate. It has been found that increasing temperature and residence time improve the cracking of tars, gas production and char quality (fixed carbon rate more than 90%, volatile matter rate less than 4%). The increase of biomass flow rate leads to a bad char quality. The efficiency of tar cracking, the quality and the heating value of the charcoal and the gases, indicate that: temperature between 650 C and 750 C, residence time of 30 min, biomass flow rate between 10 and 15 kg/h should be the most convenient experimental conditions to get better results from the experimental device and from the biomass pyrolysis process. The kinetic study of charcoal generation shows that the pyrolysis process, in experimental conditions, is a first-order reaction. The kinetic parameters calculated are comparable with those found by other researchers. (author)

  9. A two-stage process with temperature-shift for enhanced anthocyanin production in strawberry cell suspension cultures

    Institute of Scientific and Technical Information of China (English)

    张卫; Shintaro; Furusaki; Chris; Franco

    1999-01-01

    A two-stage process with temperature-shift has been developed to enhance the anthocyanin yield in suspension cultures of strawberry cells. The effect of the temperature-shift interval and the shift-time point was investigated for the optimization of this strategy. In this process, strawberry cells were grown at 30℃ (the optimum temperature for cell growth) for a certain period as the first stage, with the temperature shifted to a lower temperature for the second stage. In response to the temperature shift-down, anthoeyanin synthesis was stimulated and a higher content could be achieved than that at both boundary temperatures but cell growth was suppressed. When the lower boundary temperature was deereased, cell growth was lowered and a delayed, sustained maximum anthocyanin content was achieved. Anthocyanin synthesis was strongly influeneed by the shift-time point but cell growth was not. Consequently, the maximum anthocyanin content of 2.7 mg(?)g-fresh cell-1 was obtained on day 9 by a temperature-

  10. Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

    Science.gov (United States)

    Grübel, Klaudiusz; Suschka, Jan

    2015-05-01

    The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

  11. Sensory shelf life estimation of minimally processed lettuce considering two stages of consumers' decision-making process.

    Science.gov (United States)

    Ares, Gastón; Giménez, Ana; Gámbaro, Adriana

    2008-01-01

    The aim of the present work was to study the influence of context, particularly the stage of the decision-making process (purchase vs consumption stage), on sensory shelf life of minimally processed lettuce. Leaves of butterhead lettuce were placed in common polypropylene bags and stored at 5, 10 and 15 degrees C. Periodically, a panel of six assessors evaluated the appearance of the samples, and a panel of 40 consumers evaluated their appearance and answered "yes" or "no" to the questions: "Imagine you are in a supermarket, you want to buy a minimally processed lettuce, and you find a package of lettuce with leaves like this, would you normally buy it?" and "Imagine you have this leaf of lettuce stored in your refrigerator, would you normally consume it?". Survival analysis was used to calculate the shelf lives of minimally processed lettuce, considering both decision-making stages. Shelf lives estimated considering rejection to purchase were significantly lower than those estimated considering rejection to consume. Therefore, in order to be conservative and assure the products' quality, shelf life should be estimated considering consumers' rejection to purchase instead of rejection to consume, as traditionally has been done. On the other hand, results from logistic regressions of consumers' rejection percentage as a function of the evaluated appearance attributes suggested that consumers considered them differently while deciding whether to purchase or to consume minimally processed lettuce.

  12. Removal Natural Organic Matter (NOM in Peat Water from Wetland Area by Coagulation-Ultrafiltration Hybrid Process with Pretreatment Two-Stage Coagulation

    Directory of Open Access Journals (Sweden)

    Mahmud Mahmud

    2013-11-01

    Full Text Available The primary problem encountered in the application of membrane technology was membrane fouling. During this time, hybrid process by coagulation-ultrafiltration in drinking water treatment that has been conducted by some research, using by one-stage coagulation. The goal of this research was to investigate the effect of two-stage coagulation as a pretreatment towards performance of the coagulation-ultrafiltration hybrid process for removal NOM in the peat water. Coagulation process, either with the one-stage or two-stage coagulation was very good in removing charge hydrophilic fraction, i.e. more than 98%. NOM fractions of the peat water, from the most easily removed by the two-stage coagulation and one-stage coagulation process was charged hydrophilic>strongly hydrophobic>weakly hydrophobic>neutral hydrophilic. The two-stage coagulation process could removed UV254 and colors with a little better than the one-stage coagulation at the optimum coagulant dose. Neutral hydrophilic fraction of peat water NOM was the most influential fraction of UF membrane fouling. The two-stage coagulation process better in removing the neutral hidrophilic fraction, while removing of the charged hydrophilic, strongly hydrophobic and weakly hydrophobic similar to the one-stage coagulation. Hybrid process by pretreatment with two-stage coagulation, beside can increased removal efficiency of UV254 and color, also can reduced fouling rate of the ultrafiltration membraneIt must not exceed 250 words, contains a brief summary of the text, covering the whole manuscript without being too elaborate on every section. Avoid any abbreviation, unless it is a common knowledge or has been previously stated.

  13. Performance and microbial community analysis of two-stage process with extreme thermophilic hydrogen and thermophilic methane production from hydrolysate in UASB reactors

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2011-01-01

    The two-stage process for extreme thermophilic hydrogen and thermophilic methane production from wheat straw hydrolysate was investigated in up-flow anaerobic sludge bed (UASB) reactors. Specific hydrogen and methane yields of 89ml-H2/g-VS (190ml-H2/g-sugars) and 307ml-CH4/g-VS, respectively were...

  14. Treatment of natural rubber processing wastewater using a combination system of a two-stage up-flow anaerobic sludge blanket and down-flow hanging sponge system.

    Science.gov (United States)

    Tanikawa, D; Syutsubo, K; Hatamoto, M; Fukuda, M; Takahashi, M; Choeisai, P K; Yamaguchi, T

    2016-01-01

    A pilot-scale experiment of natural rubber processing wastewater treatment was conducted using a combination system consisting of a two-stage up-flow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) reactor for more than 10 months. The system achieved a chemical oxygen demand (COD) removal efficiency of 95.7% ± 1.3% at an organic loading rate of 0.8 kg COD/(m(3).d). Bacterial activity measurement of retained sludge from the UASB showed that sulfate-reducing bacteria (SRB), especially hydrogen-utilizing SRB, possessed high activity compared with methane-producing bacteria (MPB). Conversely, the acetate-utilizing activity of MPB was superior to SRB in the second stage of the reactor. The two-stage UASB-DHS system can reduce power consumption by 95% and excess sludge by 98%. In addition, it is possible to prevent emissions of greenhouse gases (GHG), such as methane, using this system. Furthermore, recovered methane from the two-stage UASB can completely cover the electricity needs for the operation of the two-stage UASB-DHS system, accounting for approximately 15% of the electricity used in the natural rubber manufacturing process.

  15. Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol Wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xuefei; REN Nanqi

    2007-01-01

    In this study,the two-stage upflow anaerobic sludge blanket(UASB)system and batch experiments were employed to evaluate the performance of anaerobic digestion for the treatment of high concentration methanol wastewater.The acid resistance of granular sludge and methanogenic bacteria and their metabolizing activity were investigated.The results show that the pH of the first UASB changed from 4.9 to 5.8 and 5.5 to 6.2 for the second reactor.Apparently,these were not the advisable pH levels that common metha nogenic bacteria could accept.The methanogenic bacteria of the system,viz.Methanosarcina barkeri,had some acid resistance and could still degrade methanol at pH 5.0.If the methanogenic bacteria were trained further,their acid resistance would be improved somewhat.Granular sludge of the system could protect the methanogenic bacteria within its body against the impact of the acidic environment and make them degrade methanol at pH 4.5.The performance of granular sludge was attributed to its structure,bacteria species,and the distribution of bacterium inside the granule.

  16. Production of Limonoids with Insect Antifeedant Activity in a Two-Stage Bioreactor Process with Cell Suspension Culture of Azadirachta indica.

    Science.gov (United States)

    Vásquez-Rivera, Andrés; Chicaiza-Finley, Diego; Hoyos, Rodrigo A; Orozco-Sánchez, Fernando

    2015-09-01

    Neem tree (Azadirachta indica) cell suspension culture is an alternative for the production of limonoids for insect control that overcomes limitations related to the supply of neem seeds. To establish conditions for cell growth and azadiracthin-related limonoid production, the effect of different sucrose concentrations, nitrate and phosphate in Murashige and Skoog (MS) medium, and the addition of one precursor and three elicitors was evaluated in shake flasks. The process was scaled up to a 3-l stirred tank bioreactor in one- and two-stage batch cultivation. In shake flasks, more than fivefold increase in the production of limonoids with the modified MS medium was observed (increase from 0.77 to 4.52 mg limonoids/g dry cell weight, DCW), while an increase of more than fourfold was achieved by adding the elicitors chitosan, salicylic acid, and jasmonic acid together (increase from 1.03 to 4.32 mg limonoids/g DCW). In the bioreactor, the volumetric production of limonoids was increased more than threefold with a two-stage culture in day 18 (13.82 mg limonoids/l in control single-stage process and 41.44 mg/l in two-stage process). The cultivation and operating mode of the bioreactor reported in this study may be adapted and used in optimization and process plant development for production of insect antifeedant limonoids with A. indica cell suspension cultures.

  17. Ethanolic fermentation in whey and whey-molasses mixtures. Pt. 2. Two-stage fermentation process of ethanol production from whey and beet molasses

    Energy Technology Data Exchange (ETDEWEB)

    Zakrzewski, E.; Zmarlicki, S.

    1988-01-01

    A two-stage fermentation process has been developed for ethanol production from regular or partly concentrated whey and molasses. In the first stage ethanolic fermentation in whey is performed with Kluyveromyces marxianus subsp. marxianus. Such prefermented whey is then used for dilution of molasses instead of water and the resulting medium subjected to the second stage fermentation performed with Saccharomyces cerevisiae. The process enables complete fermentation of lactose and all fermentble sugars from molasses, leading to an ethanol content of about 10% in the final medium, which makes the distillation much more economical than the separate processing of whey and molasses into spirit.

  18. An Integrated Process of a Two-Stage Fixed Bed Syngas Production and F-T Synthesis for GTL in Remote Gas Field

    Institute of Scientific and Technical Information of China (English)

    代小平; 余长春; 等

    2003-01-01

    A novel process for catalytic oxidation of methane to synthesis gas (syngas),which consists of two consecutive fixed-bed reactors with air introduced into the reactors,integrated Fischer-Tropsch synthesis,was investigated.At the Same time,a catalytic combustion technology has been investigated for utilizing the F-T offgas to generate heat or powr energy.The results show that the two-stage fixed reactor process keep away from explosion of CH4/O2.The integrated process is fitted to produce diesel oil and lubricating oil in remote gas field.

  19. A novel full recycling process through two-stage anaerobic treatment of distillery wastewater for bioethanol production from cassava.

    Science.gov (United States)

    Zhang, Qing-Hua; Lu, Xin; Tang, Lei; Mao, Zhong-Gui; Zhang, Jian-Hua; Zhang, Hong-Jian; Sun, Fu-Bao

    2010-07-15

    In the present study, a novel full recycling process for bioethanol production was investigated, where three mathematical models were established to simulate the accumulation of major soluble inhibitory substances, including organic compounds, total ions, volatile fatty acids (VFAs) and colorants. These inhibitory substances in the reused water reached a relative steady state after 3-7 batches of anaerobic treatment and recycling process, which coincided with the results of mathematical models. There were no negative effects of these inhibitory substances on ethanol fermentation and the final ethanol yield, fermentation time, starch utilization ratio were very close to that of the conventional process using tap water. However, approximately 7.54% (w/w) of water was lost during each circulation, which was replenished in subsequent circulations, to assure consistent fermentation broth volume. This novel process was confirmed to have a stable operation over 13 recycles. It is concluded the stable states of the inhibitory substances in the reused water can assure this recycling process will run successfully.

  20. Two-stage coal liquefaction process materials from the Wilsonville Facility operated in the nonintegrated and integrated modes: chemical analyses and biological testing

    Energy Technology Data Exchange (ETDEWEB)

    Later, D.W.

    1985-01-01

    This document reports the results from chemical analyses and biological testing of process materials sampled during operation of the Wilsonville Advanced Coal Liquefaction Research and Development Facility (Wilsonville, Alabama) in both the noncoupled or nonintegrated (NTSL Run 241) and coupled or integrated (ITSL Run 242) two-stage liquefaction operating modes. Mutagenicity and carcinogenicity assays were conducted in conjunction with chromatographic and mass spectrometric analyses to provide detailed, comparative chemical and biological assessments of several NTSL and ITSL process materials. In general, the NTSL process materials were biologically more active and chemically more refractory than analogous ITSL process materials. To provide perspective, the NTSL and ITSL results are compared with those from similar testing and analyses of other direct coal liquefaction materials from the solvent refined coal (SRC) I, SRC II and EDS processes. Comparisons are also made between two-stage coal liquefaction materials from the Wilsonville pilot plant and the C.E. Lummus PDU-ITSL Facility in an effort to assess scale-up effects in these two similar processes. 36 references, 26 figures, 37 tables.

  1. Two-stage anaerobic and post-aerobic mesophilic digestion of sewage sludge: Analysis of process performance and hygienization potential.

    Science.gov (United States)

    Tomei, M Concetta; Mosca Angelucci, Domenica; Levantesi, Caterina

    2016-03-01

    Sequential anaerobic-aerobic digestion has been demonstrated to be effective for enhanced sludge stabilization, in terms of increased solid reduction and improvement of sludge dewaterability. In this study, we propose a modified version of the sequential anaerobic-aerobic digestion process by operating the aerobic step under mesophilic conditions (T=37 °C), in order to improve the aerobic degradation kinetics of soluble and particulate chemical oxygen demand (COD). Process performance has been assessed in terms of "classical parameters" such as volatile solids (VS) removal, biogas production, COD removal, nitrogen species, and polysaccharide and protein fate. The aerobic step was operated under intermittent aeration to achieve nitrogen removal. Aerobic mesophilic conditions consistently increased VS removal, providing 32% additional removal vs. 20% at 20 °C. Similar results were obtained for nitrogen removal, increasing from 64% up to 99% at the higher temperature. Improved sludge dewaterability was also observed with a capillary suction time decrease of ~50% during the mesophilic aerobic step. This finding may be attributable to the decreased protein content in the aerobic digested sludge. The post-aerobic digestion exerted a positive effect on the reduction of microbial indicators while no consistent improvement of hygienization related to the increased temperature was observed. The techno-economic analysis of the proposed digestion layout showed a net cost saving for sludge disposal estimated in the range of 28-35% in comparison to the single-phase anaerobic digestion.

  2. A two-stage process using electrokinetic remediation and electrochemical degradation for treating benzo[a]pyrene spiked kaolin.

    Science.gov (United States)

    Gómez, J; Alcántara, M T; Pazos, M; Sanromán, M A

    2009-03-01

    An innovative process that combines soil electrokinetic remediation and liquid electrochemical oxidation for the degradation of organic compounds present in a polluted soil was developed and evaluated by using benzo[a]pyrene spiked kaolin. In order to increase benzo[a]pyrene solubility during electrokinetic treatment, the addition of a co-solvent or surfactant, such as ethanol or Brij 35, as flushing solution was tested. The research carried out demonstrated the influence of the desorption agent employed on benzo[a]pyrene remediation from the kaolin matrix. Thus, if the flushing solution was ethanol at 40%, there was no presence of contaminant in either chamber. On the contrary, when a solution of surfactant Brij 35 was used, benzo[a]pyrene was transported towards the cathode chamber, where it was collected. Moreover, the extent of this recovery depends on the pH profile on the soil. When no pH control was used, around 17% of initial contaminant was detected in the cathode chamber; however, when pH control was applied, the recovery of benzo[a]pyrene could be higher than 76%, when the pH control in the anode chamber was set at 7.0. In order to obtain the total degradation of mobilised benzo[a]pyrene from the contaminated soil, the liquid collected by electrokinetic remediation was oxidised by electrochemical treatment. This oxidation was accomplished via an electrochemical cell with a working volume of 0.4 L, and graphite as electrode material. The benzo[a]pyrene was almost totally degraded in 1d, reaching a degradation of about 73% in 16 h.

  3. Biological testing and chemical analysis of process materials from an integrated two stage coal liquefaction: a status report

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, B.W.; Buhl, P.; Moroni, E.C.

    1983-07-01

    Samples for chemical characterization and biological testing were obtained from ITSL runs 3LCF7, 3LCF8 and 3LCF9. Chemical analysis of these materials showed that SCT products were composed of fewer compounds than analogous materials from Solvent Refined Coal (SRC) processes. Major components in the SCT materials were three-, four-, five- and six-ring neutral polycyclic aromatic hydrocarbons (PAH). Methyl(C/sub 1/) and C/sub 2/ homologs of these compounds were present in relatively low concentrations, compared to their non-alkylated homologs. Organic nitrogen was primarily in the form of tertiary polycyclic aromatic nitrogen heterocycles and carbazoles. Little or no amino PAH (APAH) or cyano PAH were detected in samples taken during normal PDU operations, however, mutagenic APAH were produced during off-normal operation. Microbial mutagenicity appeared to be due mainly to the presence of APAH which were probably formed in the LC finer due to failure of the catalyst to promote deamination following carbon-nitrogen bond scission of nitrogen-containing hydroaromatics. This failure was observed for the off-normal runs where it was likely that the catalyst had been deactivated. Carcinogenic activity of ITSL materials as assessed by (tumors per animal) in the initiation/promotion mouse skin painting assay was slightly reduced for materials produced with good catalyst under normal operation compared to those collected during recycle of the LC Finer feed. Initiation activity of the latter samples did not appear to be significantly different from that of other coal derived materials with comparable boiling ranges. The observed initiation activity was not unexpected, considering analytical data which showed the presence of four-, five- and six-ring PAH in ITSL materials.

  4. Reconfigured, close-coupled reconfigured, and Wyodak coal integrated two-stage coal liquefaction process materials from the Wilsonville facility: Chemical and toxicological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Wright, C.W.

    1987-03-01

    This document reports the results of the chemical analysis and toxicological testing of process materials sampled during the operation of the Advanced Coal Liquefaction Research and Development Facility (Wilsonville, AL) in the reconfigured, integrated (RITSL run No. 247), the close-coupled, reconfigured, integrated (CCRITSL run No. 249), and the Wyodak coal integrated (ITSL run No. 246) two-stage liquefaction operating modes. Chemical methods of analysis included proton nuclear magnetic resonance spectroscopy, adsorption column chromatography, high resolution gas chromatography, gas chromatography/mass spectrometry, and low-voltage probe-inlet mass spectrometry. Toxicological evaluation of the process materials included a histidine reversion assay for microbial mutagenicity, an initiation/promotion assay for tumorigenicity in mouse skin, and an aquatic toxicity assay using Daphnia magna. The results of these analyses and tests are compared to the previously reported results derived from the Illinois No. 6 coal ITSL and nonintegrated two-stage liquefaction (NTSL) process materials from the Wilsonville facility. 21 refs., 13 figs., 21 tabs.

  5. A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover.

    Science.gov (United States)

    Li, Wenzhi; Liu, Qiyu; Ma, Qiaozhi; Zhang, Tingwei; Ma, Longlong; Jameel, Hasan; Chang, Hou-Min

    2016-11-01

    A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Effect of aerobic pre-treatment on hydrogen and methane production in a two-stage anaerobic digestion process using food waste with different compositions.

    Science.gov (United States)

    Rafieenia, Razieh; Girotto, Francesca; Peng, Wei; Cossu, Raffaello; Pivato, Alberto; Raga, Roberto; Lavagnolo, Maria Cristina

    2017-01-01

    Aerobic pre-treatment was applied prior to two-stage anaerobic digestion process. Three different food wastes samples, namely carbohydrate rich, protein rich and lipid rich, were prepared as substrates. Effect of aerobic pre-treatment on hydrogen and methane production was studied. Pre-aeration of substrates showed no positive impact on hydrogen production in the first stage. All three categories of pre-aerated food wastes produced less hydrogen compared to samples without pre-aeration. In the second stage, methane production increased for aerated protein rich and carbohydrate rich samples. In addition, the lag phase for carbohydrate rich substrate was shorter for aerated samples. Aerated protein rich substrate yielded the best results among substrates for methane production, with a cumulative production of approximately 351ml/gVS. With regard to non-aerated substrates, lipid rich was the best substrate for CH4 production (263ml/gVS). Pre-aerated P substrate was the best in terms of total energy generation which amounted to 9.64kJ/gVS. This study revealed aerobic pre-treatment to be a promising option for use in achieving enhanced substrate conversion efficiencies and CH4 production in a two-stage AD process, particularly when the substrate contains high amounts of proteins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Effective conversion of maize straw wastes into bio-hydrogen by two-stage process integrating H2 fermentation and MECs.

    Science.gov (United States)

    Li, Yan-Hong; Bai, Yan-Xia; Pan, Chun-Mei; Li, Wei-Wei; Zheng, Hui-Qin; Zhang, Jing-Nan; Fan, Yao-Ting; Hou, Hong-Wei

    2015-12-01

    The enhanced H2 production from maize straw had been achieved through the two-stage process of integrating H2 fermentation and microbial electrolysis cells (MECs) in the present work. Several key parameters affecting hydrolysis of maize straw through subcritical H2O were optimized by orthogonal design for saccharification of maize straw followed by H2 production through H2 fermentation. The maximum reducing sugar (RS) content of maize straw reached 469.7 mg/g-TS under the optimal hydrolysis condition with subcritical H2O combining with dilute HCl of 0.3% at 230 °C. The maximum H2 yield, H2 production rate, and H2 content was 115.1 mL/g-TVS, 2.6 mL/g-TVS/h, and 48.9% by H2 fermentation, respectively. In addition, the effluent from H2 fermentation was used as feedstock of MECs for additional H2 production. The maximum H2 yield of 1060 mL/g-COD appeared at an applied voltage of 0.8 V, and total COD removal reached about 35%. The overall H2 yield from maize straw reached 318.5 mL/g-TVS through two-stage processes. The structural characterization of maize straw was also carefully investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectra.

  8. Mass cultivation of microalgae on animal wastewater: a sequential two-stage cultivation process for energy crop and omega-3-rich animal feed production.

    Science.gov (United States)

    Zhou, Wenguang; Hu, Bing; Li, Yecong; Min, Min; Mohr, Michael; Du, Zhenyi; Chen, Paul; Ruan, Roger

    2012-09-01

    In this study, 97 microalgal strains purchased from algae bank and 50 microalgal strains isolated from local waters in Minnesota were screened for their adaptability growing on a 20-fold diluted digested swine manure wastewater (DSMW). A pool of candidate strains well adapted to the DSMW was established through a high-throughput screening process. Two top-performing facultative heterotrophic strains with high growth rate (0.536 day(-1) for UMN 271 and 0.433 day(-1) for UMN 231) and one strain with high omega-3 unsaturated fatty acid (EPA, 3.75 % of total fatty acids for UMN 231) were selected. Subsequently, a sequential two-stage mixo-photoautotrophic culture strategy was developed for biofuel and animal feed production as well as simultaneous swine wastewater treatment using above two strains. The maximal biomass concentration and lipid content at the first and second stages reached 2.03 g/L and 23.0 %, and 0.83 g/L and 19.0 % for UMN 271 and UMN 231, respectively. The maximal nutrient removals for total phosphorus and ammonia after second-stage cultivation were 100 and 89.46 %, respectively. The experiments showed that this sequential two-stage cultivation process has great potential for economically viable and environmentally friendly production of both renewable biofuel and high-value animal feed and at the same time for animal wastewater treatment.

  9. Performance and microbial community analysis of two-stage process with extreme thermophilic hydrogen and thermophilic methane production from hydrolysate in UASB reactors.

    Science.gov (United States)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2011-03-01

    The two-stage process for extreme thermophilic hydrogen and thermophilic methane production from wheat straw hydrolysate was investigated in up-flow anaerobic sludge bed (UASB) reactors. Specific hydrogen and methane yields of 89 ml-H(2)/g-VS (190 ml-H(2)/g-sugars) and 307 ml-CH(4)/g-VS, respectively were achieved simultaneously with the overall VS removal efficiency of 81% by operating with total hydraulic retention time (HRT) of 4 days . The energy conversion efficiency was dramatically increased from only 7.5% in the hydrogen stage to 87.5% of the potential energy from hydrolysate, corresponding to total energy of 13.4 kJ/g-VS. Dominant hydrogen-producing bacteria in the H(2)-UASB reactor were Thermoanaerobacter wiegelii, Caldanaerobacter subteraneus, and Caloramator fervidus. Meanwhile, the CH(4)-UASB reactor was dominated with methanogens of Methanosarcina mazei and Methanothermobacter defluvii. The results from this study suggest the two stage anaerobic process can be effectively used for energy recovery and for stabilization of hydrolysate at anaerobic conditions.

  10. Eliminating methanogenic activity in hydrogen reactor to improve biogas production in a two-stage anaerobic digestion process co-digesting municipal food waste and sewage sludge.

    Science.gov (United States)

    Zhu, Heguang; Parker, Wayne; Conidi, Daniela; Basnar, Robert; Seto, Peter

    2011-07-01

    Laboratory scale two-stage anaerobic digestion process model was operated for 280 days to investigate the feasibility to produce both hydrogen and methane from a mixture feedstock (1:1 (v/v)) of municipal food waste and sewage sludge. The maximum hydrogen and methane yields obtained in the two stages were 0.93 and 9.5 mL/mL feedstock. To eliminate methanogenic activity and obtain substantial hydrogen production in the hydrogen reactor, both feedstock and mixed liquor required treatment. The heat treatment (100°C, 10 min) for feedstock and a periodical treatment (every 2-5 weeks, either heating, removal of biomass particles or flushing with air) for mixed liquor were effective in different extent. The methane production in the second stage was significantly improved by the hydrogen production in the first stage. The maximum methane production obtained in the period of high hydrogen production was more than 2-fold of that observed in the low hydrogen production period.

  11. Preparation of Cd(Zn)Te and CuInSe sub 2 films and devices by a two-stage process

    Energy Technology Data Exchange (ETDEWEB)

    Basol, B.M.; Kapur, V.K. (International Solar Electric Technology (ISET), Inglewood, CA (USA))

    1991-05-01

    The two-stage process was used to prepare thin films of Cd(Zn)Te and CuInSe{sub 2}. The technique involves first depositing the elemental components of the compound onto a substrate in the form of thin stacked layers and then reacting these elemental components to obtain a thin film of the desired compound. While CdTe films grown on thin CdS layers have uniform stoichiometries and sharp interfaces with the underlying CdS layers, CdZnTe films deposited onto similar substrates give rise to diffused CdZnTe-CdS interfaces because of the reactive nature of zinc. In CuInSe{sub 2} processing, the nature of the reacted compound film strongly depends on the nature of the Cu-In layers. CdS/CuInSe{sub 2} device efficiencies are also influenced by the method of deposition for the CdS window layers. (orig.).

  12. Catalytic Two-Stage Liquefaction (CTSL{trademark}) process bench studies and PDU scale-up with sub-bituminous coal. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Comolli, A.G.; Johanson, E.S.; Karolkiewicz, W.F.; Lee, L.K.T.; Stalzer, R.H.; Smith, T.O.

    1993-03-01

    Reported are the details and results of Laboratory and Bench-Scale experiments using sub-bituminous coal conducted at Hydrocarbon Research, Inc., under DOE Contract No. DE-AC22-88PC88818 during the period October 1, 1988 to December 31, 1992. The work described is primarily concerned with testing of the baseline Catalytic Two-Stage Liquefaction (CTSL{trademark}) process with comparisons with other two stage process configurations, catalyst evaluations and unit operations such as solid separation, pretreatments, on-line hydrotreating, and an examination of new concepts. In the overall program, three coals were evaluated, bituminous Illinois No. 6, Burning Star and sub-bituminous Wyoming Black Thunder and New Mexico McKinley Mine seams. The results from a total of 16 bench-scale runs are reported and analyzed in detail. The runs (experiments) concern process variables, variable reactor volumes, catalysts (both supported, dispersed and rejuvenated), coal cleaned by agglomeration, hot slurry treatments, reactor sequence, on-line hydrotreating, dispersed catalyst with pretreatment reactors and CO{sub 2}/coal effects. The tests involving the Wyoming and New Mexico Coals are reported herein, and the tests involving the Illinois coal are described in Topical Report No. 2. On a laboratory scale, microautoclave tests evaluating coal, start-up oils, catalysts, thermal treatment, CO{sub 2} addition and sulfur compound effects were conducted and reported in Topical Report No. 3. Other microautoclave tests are described in the Bench Run sections to which they refer such as: rejuvenated catalyst, coker liquids and cleaned coals. The microautoclave tests conducted for modelling the CTSL{trademark} process are described in the CTSL{trademark} Modelling section of Topical Report No. 3 under this contract.

  13. Two stage leaching process of copper-cobalt oxide ore in Central Africa%中非铜-钴氧化矿两段浸出过程

    Institute of Scientific and Technical Information of China (English)

    李淑梅; 刘凯华; 李辉; 丛自范

    2015-01-01

    A two stage leaching process of the copper-cobalt oxide ore from Africa was investigated. The two stage leaching process was used to realize selective leaching of copper and cobalt in the ore. The first stage was the leaching of copper in ore using sulfuric acid, and the second stage was the leaching of cobalt using sulfuric acid and reductant. The optimum conditions for the first stage are as follows: the ratio of ore less than 75μm is 89%, sulfuric acid mass fraction of the ore is 13%, liquid-solid ratio is 4:1, leaching time is 60 min and temperature is 25℃. The optimum conditions for the second stage are follows: liquid-solid ratio is 4:1, temperature is 65℃, time is 150 min, initial acid concentration is 20 g/L and reductant dosage is 1.5 times of the theory amount. The results show that the leaching efficiencies of copper and cobalt in two stage leaching process reach 97.13% and 96.05%, respectively.%研究一种非洲铜−钴氧化矿两段浸出过程。采取两段浸出的目的是实现矿石中铜和钴的选择性浸出。第一段主要用硫酸浸出矿石中的铜,第二段用硫酸和还原剂浸出矿石中的钴。第一段浸出的最佳技术条件:矿石粒度小于75μm的比例占89%,硫酸加入量为铜−钴氧化矿质量的13%,液固比为4:1,浸出时间为60 min,温度为常温(25℃);第二段浸出的最佳技术条件:浸铜渣液固比为4:1,温度为65℃,时间为150 min,初始酸浓度为20 g/L,还原剂加入量为理论量的1.5倍。结果表明:两段浸出过程铜和钴的浸出率分别达到97.13%和96.05%。

  14. Description of two-stage processes in reactions of nucleon and cluster knock out by medium-energy protons on the basis of the effective t-matrix

    Energy Technology Data Exchange (ETDEWEB)

    Vdovin, A.I.; Golovin, A.V.; Loshchakov, I.I.

    1986-06-01

    We propose to calculate the amplitude for the two-stage processes in reactions of nucleon and cluster knock out from light nuclei by medium-energy protons as a coherent sum of amplitudes of the probability of the quasielastic pp (or px) interaction and of inelastic proton scattering by the target nucleus with formation of excited states of the intermediate nucleus and with their subsequent decay with emission of a nucleon or a particle x. The reaction matrix element is calculated on the basis of the t-matrix distorted-wave approximation. All functions entering into the matrix element are given analytically, which allows the analytic calculation of multidimensional integrals entering into the matrix element. The calculations of the energy spectra of protons carried out with this model are in good agreement with experiment.

  15. Changes in physical, chemical, and microbiological properties during the two-stage co-composting of green waste with spent mushroom compost and biochar.

    Science.gov (United States)

    Zhang, Lu; Sun, Xiangyang

    2014-11-01

    This research determined whether the two-stage co-composting can be used to convert green waste (GW) into a useful compost. The GW was co-composted with spent mushroom compost (SMC) (at 0%, 35%, and 55%) and biochar (BC) (at 0%, 20%, and 30%). The combined addition of SMC and BC greatly increased the nutrient contents of the compost product and also improved the compost quality in terms of composting temperature, particle-size distribution, free air space, cation exchange capacity, nitrogen transformation, organic matter degradation, humification, element contents, abundance of aerobic heterotrophs, dehydrogenase activity, and toxicity to germinating seeds. The addition of 35% SMC and 20% BC to GW (dry weight % of initial GW) and the two-stage co-composting technology resulted in the production of the highest quality compost product in only 24 days rather than the 90-270 days required with traditional composting.

  16. Close-coupled Catalytic Two-Stage Liquefaction (CTSL{trademark}) process bench studies. Final report, [October 1, 1988--July 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Comolli, A.G.; Johanson, E.S.; Karolkiewicz, W.F.; Lee, L.K.; Popper, G.A.; Stalzer, R.H.; Smith, T.O.

    1993-06-01

    This is the final report of a four year and ten month contract starting on October 1, 1988 to July 31, 1993 with the US Department of Energy to study and improve Close-Coupled Catalytic Two-Stage Direct Liquefaction of coal by producing high yields of distillate with improved quality at lower capital and production costs in comparison to existing technologies. Laboratory, Bench and PDU scale studies on sub-bituminous and bituminous coals are summarized and referenced in this volume. Details are presented in the three topical reports of this contract; CTSL Process Bench Studies and PDU Scale-Up with Sub-Bituminous Coal-DE-88818-TOP-1, CTSL Process Bench Studies with Bituminous Coal-DE-88818-TOP-2, and CTSL Process Laboratory Scale Studies, Modelling and Technical Assessment-DE-88818-TOP-3. Results are summarized on experiments and studies covering several process configurations, cleaned coals, solid separation methods, additives and catalysts both dispersed and supported. Laboratory microautoclave scale experiments, economic analysis and modelling studies are also included along with the PDU-Scale-Up of the CTSL processing of sub-bituminous Black Thunder Mine Wyoming coal. During this DOE/HRI effort, high distillate yields were maintained at higher throughput rates while quality was markedly improved using on-line hydrotreating and cleaned coals. Solid separations options of filtration and delayed coking were evaluated on a Bench-Scale with filtration successfully scaled to a PDU demonstration. Directions for future direct coal liquefaction related work are outlined herein based on the results from this and previous programs.

  17. Production of poly(hydroxybutyrate-hydroxyvalerate) from waste organics by the two-stage process: focus on the intermediate volatile fatty acids.

    Science.gov (United States)

    Shen, Liang; Hu, Hongyou; Ji, Hongfang; Cai, Jiyuan; He, Ning; Li, Qingbiao; Wang, Yuanpeng

    2014-08-01

    The two-stage process, coupling volatile fatty acids (VFAs) fermentation and poly(hydroxybutyrate-hydroxyvalerate) (P(HB/HV)) biosynthesis, was investigated for five waste organic materials. The overall conversion efficiencies were glycerol>starch>molasses>waste sludge>protein, meanwhile the maximum P(HB/HV) (1.674 g/L) was obtained from waste starch. Altering the waste type brought more effects on VFAs composition other than the yield in the first stage, which in turn greatly changed the yield in the second stage. Further study showed that even-number carbon VFAs (or odd-number ones) had a good positive linear relationship with P(HB/HV) content of HB (or HV). Additionally, VFA producing microbiota was analyzed by pyrosequencing methods for five wastes, which indicated that specific species (e.g., Lactobacillus for protein; Ethanoligenens for starch; Ruminococcus and Limnobacter for glycerol) were dominant in the community for VFAs production. Potential competition among acidogenic bacteria specially involved to produce some VFA was proposed as well.

  18. High Performance Gasification with the Two-Stage Gasifier

    DEFF Research Database (Denmark)

    Gøbel, Benny; Hindsgaul, Claus; Henriksen, Ulrik Birk

    2002-01-01

    Based on more than 15 years of research and practical experience, the Technical University of Denmark (DTU) and COWI Consulting Engineers and Planners AS present the two-stage gasification process, a concept for high efficiency gasification of biomass producing negligible amounts of tars. In the ......Based on more than 15 years of research and practical experience, the Technical University of Denmark (DTU) and COWI Consulting Engineers and Planners AS present the two-stage gasification process, a concept for high efficiency gasification of biomass producing negligible amounts of tars....... In the two-stage gasification concept, the pyrolysis and the gasification processes are physical separated. The volatiles from the pyrolysis are partially oxidized, and the hot gases are used as gasification medium to gasify the char. Hot gases from the gasifier and a combustion unit can be used for drying...... a cold gas efficiency exceeding 90% is obtained. In the original design of the two-stage gasification process, the pyrolysis unit consists of a screw conveyor with external heating, and the char unit is a fixed bed gasifier. This design is well proven during more than 1000 hours of testing with various...

  19. Characteristics of a-GaN films and a-AlGaN/GaN heterojunctions prepared on r-sapphire by two-stage growth process

    Science.gov (United States)

    Polyakov, A. Y.; Jang, Lee-Woon; Smirnov, N. B.; Govorkov, A. V.; Kozhukhova, E. A.; Yugova, T. G.; Reznik, V. Y.; Pearton, S. J.; Baik, Kwang Hyeon; Hwang, Sung-Min; Jung, Sukkoo; Lee, In-Hwan

    2011-11-01

    The electrical properties, presence of deep electron and hole traps and photoluminescence spectra were measured for undoped a-GaN films grown by metal-organic chemical vapor deposition (MOCVD) in a two-stage process using a high V/III ratio at the first stage and low V/III ratio at the second stage. Growth was performed on r-sapphire substrates with a high temperature GaN nucleation layer. The films showed a full width at half maximum of 450-470 arcseconds for the (11-20) x-ray rocking curve with little anisotropy with respect to the sample rotation around the growth direction. The stacking fault (SF) density determined by selective etching was ˜5 × 104 cm-1. The residual donor concentration was 1014-1015 cm-3, with a very low density (2.5 × 1013 cm-3) of electron traps located at Ec - 0.6 eV, which are believed to be one of the major non-radiative recombination centers in nonpolar GaN. Consequently, the films showed a high intensity of bandedge luminescence with negligible contribution from defect bands associated with SFs. In contrast to previously studied nonpolar GaN films, the a-GaN layers showed a high concentration of gallium-vacancy-related acceptors near Ev + 1 eV and a strong yellow luminescence band, both indicating that growth conditions were effectively N-rich. a-AlGaN/GaN heterojunctions with thin heavily Si doped AlGaN barriers made on a-GaN substrates showed two-dimensional electron gas (2DEG) concentrations of 1.2 × 1013 cm-3, with 2DEG mobility of 80 cm2/Vs. Capacitance-voltage profiling of Schottky diodes on these HJs suggest that the 2DEG is fully depleted by the built-in voltage of the Schottky diode.

  20. Two-stage digestion of renewable raw materials. Applying the flooding process to utilizing grass silage; Zweiphasige Vergaerung nachwachsender Rohstoffe. Einsatz des Einstau-Verfahrens zur Verwertung von Grassilage

    Energy Technology Data Exchange (ETDEWEB)

    Zielonka, S.; Lemmer, A.; Oechsner, H. [Hohenheim Univ. (Germany). Landesanstalt fuer Landwirtschaftliches Maschinen- und Bauwesen; Jungbluth, T. [Stuttgart Univ. (Germany). Inst. fuer Agrartechnik

    2008-08-15

    The input of fibre-rich renewable raw materials, e.g. grass silage, as a co-substrate in agricultural biogas plants, often caused technical problems. Within the framework of this project a process is being developed, which makes it possible to digest grass silage as a single substrate, a process which additionally through a two-stage process better supplies what the bacteria involved require. An intermittently operating two- stage process is being used, which has had good results with degradation and methane yields. (orig.)

  1. Evaluation of the methanogenic step of a two-stage anaerobic digestion process of acidified olive mill solid residue from a previous hydrolytic-acidogenic step.

    Science.gov (United States)

    Rincón, B; Borja, R; Martín, M A; Martín, A

    2009-09-01

    A study of the second step or methanogenic stage of a two-stage anaerobic digestion process treating two-phase olive oil mill solid residue (OMSR) was conducted at mesophilic temperature (35 degrees C). The substrate fed to the methanogenic step was the effluent from a hydrolytic-acidogenic reactor operating at an organic loading rate (OLR) of 12.9 g chemical oxygen demand (COD) L(-1) d(-1) and at a hydraulic retention time (HRT) of 12.4 days; these OLR and HRT were found to be the best values to achieve the maximum total volatile fatty acid concentration (14.5 g L(-1) expressed as acetic acid) with a high concentration in acetic acid (57.5% of the total concentration) as the principal precursor of methane. The methanogenic stage was carried out in an anaerobic stirred tank reactor containing saponite as support media for the immobilization of microorganisms. OLRs of between 0.8 and 22.0 g COD L(-1) d(-1) were studied. These OLRs corresponded to HRTs of between 142.9 and 4.6 days. The methanogenic reactor operated with high stability for OLRs lower than 20.0 g COD L(-1) d(-1). This behaviour was shown by the total volatile fatty acids/total alkalinity ratio, whose values were always kept 0.12 for HRTs>4.6 days. The total COD (T-COD) removed was in the range of 94.3-61.3% and the volatile solids (VS) removed between 92.8% and 56.1% for OLRs between 0.8 and 20.0 g COD L(-1) d(-1). In the same way, a reduction of 43.8% was achieved for phenolic content. The low concentration of total volatile fatty acids (TVFA) observed (below 1 g L(-1) expressed as CH(3)COOH) in the methanogenic reactor effluents showed the high percentage of consumption and conversion of these acids to methane. A methane yield of 0.268+/-0.003 L CH(4) at standard temperature and pressure conditions (STP) g(-1) COD eliminated was achieved.

  2. Hydrogen and methane production by co-digestion of waste activated sludge and food waste in the two-stage fermentation process: substrate conversion and energy yield.

    Science.gov (United States)

    Liu, Xinyuan; Li, Ruying; Ji, Min; Han, Li

    2013-10-01

    Batch experiments were conducted to produce hydrogen and methane from waste activated sludge and food waste by two-stage mesophilic fermentation. Hydrogen and methane production, energy yield, soluble organic matters, volatile solid removal efficiency and carbon footprint were investigated during two-stage digestion at various food waste proportions. The highest energy yield reached 14.0 kJ/g-VS at the food waste proportion of 85%, with hydrogen and methane yields of 106.4 ml-H2/g-VS and 353.5 ml-CH4/g-VS respectively. The dominant VFA composition was butyrate for co-digestion and sole food waste fermentation, whereas acetate was dominate in VFA for sole waste activated sludge fermentation. The VS removal efficiencies of co-digestion were 10-77% higher than that of waste activated sludge fermentation. Only 0.1-3.2% of the COD in feedstock was converted into hydrogen, and 14.1-40.9% to methane, with the highest value of 40.9% in methane achieved at food waste proportion of 85%. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Bioaugmentation with an anaerobic fungus in a two-stage process for biohydrogen and biogas production using corn silage and cattail.

    Science.gov (United States)

    Nkemka, Valentine Nkongndem; Gilroyed, Brandon; Yanke, Jay; Gruninger, Robert; Vedres, Darrell; McAllister, Tim; Hao, Xiying

    2015-06-01

    Bioaugmentation with an anaerobic fungus, Piromyces rhizinflata YM600, was evaluated in an anaerobic two-stage system digesting corn silage and cattail. Comparable methane yields of 328.8±16.8mLg(-1)VS and 295.4±14.5mLg(-1)VS and hydrogen yields of 59.4±4.1mLg(-1)VS and 55.6±6.7mLg(-1)VS were obtained for unaugmented and bioaugmented corn silage, respectively. Similar CH4 yields of 101.0±4.8mLg(-1)VS and 104±19.1mLg(-1)VS and a low H2 yield (biohydrogen production.

  4. Two stages of fluid-rock interaction in UHP marbles (Dabie Shan, China): grain-scale processes and map-scale metasomatism

    Science.gov (United States)

    Wawrzenitz, N. H.; Romer, R. L.; Grasemann, B.; Rhede, D.

    2012-12-01

    Fluid-mediated element mobility during ultra-deep subduction and exhumation of continental crust results in characteristic isotope signatures of UHP rocks. In the Dabie UHP complex large volumes of meta-carbonates show unusually unradiogenic 87Sr/86Sr ratios, as low as 0.7037 (Romer et al. 2003). The mineral reaction history, combined with the initial Sr isotopic record of prograde and retrograde phases of the meta-carbonates provide evidence for two stages of fluid-rock interaction during exhumation along the subduction zone. To constrain (i) the mechanisms of fluid transport through the rocks, (ii) the source of the fluid(s) and (iii) the timing of fluid-rock interactions, a calcsilicate marble has been investigated at the grain-scale. A crucial advantage of the studied sample is the record of the initial Sr isotopic signature of the carbonate rock preserved in the core of a large pre-UHP titanite (U-Pb crystallization age of 244±2 Ma, Wawrzenitz et al., 2006). Based on the results of microdrilling, ID TIMS and mineral chemical investigations, two pulses of infiltration of external fluids distinct in their Sr isotopic composition are inferred. During the first stage, fluids with very low 87Sr/86Sr values induced dissolution-precipitation reactions resulting in the isotopically homogeneous phases clinozoisite, titanite, amphibole and calcite, that replace the UHP assemblage (garnet, omphacite, rutile, phengite, aragonite, coesite) in the marble. The source of the very unradiogenic fluids may be the dehydrating young mafic rocks from the downgoing slab. Dissolution-precipitation reactions resulted in a high porosity, and efficiently supported material transport through the carbonate rock and isotope chemical exchange among fluids and rocks. This first stage of fluid-infiltration is recorded by a U-Pb isochron age (224±2 Ma, Wawrzenitz et al., 2006) of titanite, clinozoisite, feldspar, epidote from a marble from the same unit, assuming a common pressure

  5. A two-stage planning and control model toward Economically Adapted Power Distribution Systems using analytical hierarchy processes and fuzzy optimization

    Energy Technology Data Exchange (ETDEWEB)

    Schweickardt, Gustavo [Instituto de Economia Energetica, Fundacion Bariloche, Centro Atomico Bariloche - Pabellon 7, Av. Bustillo km 9500, 8400 Bariloche (Argentina); Miranda, Vladimiro [INESC Porto, Instituto de Engenharia de Sistemas e Computadores do Porto and FEUP, Faculdade de Engenharia da Universidade do Porto, R. Dr. Roberto Frias, 378, 4200-465 Porto (Portugal)

    2009-07-15

    This work presents a model to evaluate the Distribution System Dynamic De-adaptation respecting its planning for a given period of Tariff Control. The starting point for modeling is brought about by the results from a multi-criteria method based on Fuzzy Dynamic Programming and on Analytic Hierarchy Processes applied in a mid/short-term horizon (stage 1). Then, the decision-making activities using the Hierarchy Analytical Processes will allow defining, for a Control of System De-adaptation (stage 2), a Vector to evaluate the System Dynamic Adaptation. It is directly associated to an eventual series of inbalances that take place during its evolution. (author)

  6. Two-stage model for time-varying effects of discrete longitudinal covariates with applications in analysis of daily process data.

    Science.gov (United States)

    Yang, Hanyu; Cranford, James A; Li, Runze; Buu, Anne

    2015-02-20

    This study proposes a generalized time-varying effect model that can be used to characterize a discrete longitudinal covariate process and its time-varying effect on a later outcome that may be discrete. The proposed method can be applied to examine two important research questions for daily process data: measurement reactivity and predictive validity. We demonstrate these applications using health risk behavior data collected from alcoholic couples through an interactive voice response system. The statistical analysis results show that the effect of measurement reactivity may only be evident in the first week of interactive voice response assessment. Moreover, the level of urge to drink before measurement reactivity takes effect may be more predictive of a later depression outcome. Our simulation study shows that the performance of the proposed method improves with larger sample sizes, more time points, and smaller proportions of zeros in the binary longitudinal covariate.

  7. The influence of precursor Cu content and two-stage processing conditions on the microstructure of Cu{sub 2}ZnSnSe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Márquez-Prieto, J., E-mail: jose.prieto@northumbria.ac.uk [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom); Ren, Y. [Ångström Solar Center, Solid State Electronics, Uppsala University, Uppsala 751 21 (Sweden); Miles, R.W.; Pearsall, N.; Forbes, I. [Northumbria Photovoltaic Application Centre, Faculty of Engineering and Environment, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST (United Kingdom)

    2015-05-01

    This paper reports the influence of processing temperature on the microstructure of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) absorber layers for temperatures between 380 and 550 °C produced using a 2-stage process. X-ray diffraction analysis showed the formation of Cu{sub 2}ZnSnSe{sub 4} over this temperatures range. The Williamson-Hall method was used for microstructural analysis of the CZTSe absorbers, and this showed a progressive decrease of the micro-strain of the CZTSe with increasing selenisation temperature. The influence of precursor Cu content on the microstructure of the CZTSe was also studied. An increase of Cu content in the precursor is correlated to an increase in grain size and a decrease in micro-strain. Raman measurements show an asymmetrical broadening towards lower energies of the main 197 cm{sup −1} mode for Cu-poor compositions. This study provides an insight into the dependency of the crystallinity of CZTSe on composition and synthesis temperature. - Highlights: • We fabricate Cu{sub 2}ZnSnSe{sub 4} thin films by sputtering and post-reactive annealing. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases. • The micro-strain of Cu{sub 2}ZnSnSe{sub 4} decreases with increasing processing temperature. • The defect concentration of Cu{sub 2}ZnSnSe{sub 4} increases when Cu content decreases.

  8. Coal liquefaction process streams characterization and evaluation: Application of liquid chromatographic separation methods to THF-soluble portions of integrated two-stage coal liquefaction resids

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.B.; Pearson, C.D.; Young, L.L.; Green, J.A. (National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States))

    1992-05-01

    This study demonstrated the feasibility of using non-aqueous ion exchange liquid chromatography (NIELC) for the examination of the tetrahydrofuran (THF)-soluble distillation resids and THF-soluble whole oils derived from direct coal liquefaction. The technique can be used to separate the material into a number of acid, base, and neutral fractions. Each of the fractions obtained by NIELC was analyzed and then further fractionated by high-performance liquid chromatography (HPLC). The separation and analysis schemes are given in the accompanying report. With this approach, differences can be distinguished among samples obtained from different process streams in the liquefaction plant and among samples obtained at the same sampling location, but produced from different feed coals. HPLC was directly applied to one THF-soluble whole process oil without the NIELC preparation, with limited success. The direct HPLC technique used was directed toward the elution of the acid species into defined classes. The non-retained neutral and basic components of the oil were not analyzable by the direct HPLC method because of solubility limitations. Sample solubility is a major concern in the application of these techniques.

  9. Changes in microbial community during hydrogen and methane production in two-stage thermophilic anaerobic co-digestion process from biowaste.

    Science.gov (United States)

    Zahedi, S; Solera, R; Micolucci, F; Cavinato, C; Bolzonella, D

    2016-03-01

    In this paper, the microbial community in a two-phase thermophilic anaerobic co-digestion process was investigated for its role in hydrogen and methane production, treating waste activated sludge and treating the organic fraction of municipal solid waste. In the acidogenic phase, in which hydrogen is produced, Clostridium sp. clusters represented 76% of total Firmicutes. When feeding the acidogenic effluent into the methanogenic reactors, these acidic conditions negatively influenced methanogenic microorganisms: Methanosaeta sp., (Methanobacteriales, Methanomicrobiales, Methanococcales) decreased by 75%, 50%, 38% and 52%, respectively. At the same time, methanogenic digestion lowered the numbers of Clostridium sp. clusters due to both pH increasing and substrate reduction, and an increase in both Firmicutes genera (non Clostridium) and methanogenic microorganisms, especially Methanosaeta sp. (208%). This was in accordance with the observed decrease in acetic (98%) and butyric (100%) acid contents. To ensure the activity of the acetate-utilizing methanogens (AUM) and the acetogens, high ratios of H2-utilizing methanogens (HUM)/AUM (3.6) were required.

  10. Two-stage processing of sounds explains behavioral performance variations due to changes in stimulus contrast and selective attention: an MEG study.

    Directory of Open Access Journals (Sweden)

    Jaakko Kauramäki

    Full Text Available Selectively attending to task-relevant sounds whilst ignoring background noise is one of the most amazing feats performed by the human brain. Here, we studied the underlying neural mechanisms by recording magnetoencephalographic (MEG responses of 14 healthy human subjects while they performed a near-threshold auditory discrimination task vs. a visual control task of similar difficulty. The auditory stimuli consisted of notch-filtered continuous noise masker sounds, and of 1020-Hz target tones occasionally (p = 0.1 replacing 1000-Hz standard tones of 300-ms duration that were embedded at the center of the notches, the widths of which were parametrically varied. As a control for masker effects, tone-evoked responses were additionally recorded without masker sound. Selective attention to tones significantly increased the amplitude of the onset M100 response at ~100 ms to the standard tones during presence of the masker sounds especially with notches narrower than the critical band. Further, attention modulated sustained response most clearly at 300-400 ms time range from sound onset, with narrower notches than in case of the M100, thus selectively reducing the masker-induced suppression of the tone-evoked response. Our results show evidence of a multiple-stage filtering mechanism of sensory input in the human auditory cortex: 1 one at early (~100 ms latencies bilaterally in posterior parts of the secondary auditory areas, and 2 adaptive filtering of attended sounds from task-irrelevant background masker at longer latency (~300 ms in more medial auditory cortical regions, predominantly in the left hemisphere, enhancing processing of near-threshold sounds.

  11. Exoplanet atmospheres physical processes

    CERN Document Server

    Seager, Sara

    2010-01-01

    Over the past twenty years, astronomers have identified hundreds of extrasolar planets--planets orbiting stars other than the sun. Recent research in this burgeoning field has made it possible to observe and measure the atmospheres of these exoplanets. This is the first textbook to describe the basic physical processes--including radiative transfer, molecular absorption, and chemical processes--common to all planetary atmospheres, as well as the transit, eclipse, and thermal phase variation observations that are unique to exoplanets. In each chapter, Sara Seager offers a conceptual introdu

  12. The construction of two-stage tests

    NARCIS (Netherlands)

    Adema, Jos J.

    1988-01-01

    Although two-stage testing is not the most efficient form of adaptive testing, it has some advantages. In this paper, linear programming models are given for the construction of two-stage tests. In these models, practical constraints with respect to, among other things, test composition, administrat

  13. LOGISTICS SCHEDULING: ANALYSIS OF TWO-STAGE PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Yung-Chia CHANG; Chung-Yee LEE

    2003-01-01

    This paper studies the coordination effects between stages for scheduling problems where decision-making is a two-stage process. Two stages are considered as one system. The system can be a supply chain that links two stages, one stage representing a manufacturer; and the other, a distributor.It also can represent a single manufacturer, while each stage represents a different department responsible for a part of operations. A problem that jointly considers both stages in order to achieve ideal overall system performance is defined as a system problem. In practice, at times, it might not be feasible for the two stages to make coordinated decisions due to (i) the lack of channels that allow decision makers at the two stages to cooperate, and/or (ii) the optimal solution to the system problem is too difficult (or costly) to achieve.Two practical approaches are applied to solve a variant of two-stage logistic scheduling problems. The Forward Approach is defined as a solution procedure by which the first stage of the system problem is solved first, followed by the second stage. Similarly, the Backward Approach is defined as a solution procedure by which the second stage of the system problem is solved prior to solving the first stage. In each approach, two stages are solved sequentially and the solution generated is treated as a heuristic solution with respect to the corresponding system problem. When decision makers at two stages make decisions locally without considering consequences to the entire system,ineffectiveness may result - even when each stage optimally solves its own problem. The trade-off between the time complexity and the solution quality is the main concern. This paper provides the worst-case performance analysis for each approach.

  14. A TWO-STAGE SEMI-HYBRID FLOWSHOP PROBLEM IN GRAPHICS PROCESSING%图像处理中的一个两阶段半杂交流水作业问题

    Institute of Scientific and Technical Information of China (English)

    魏麒; 何勇

    2005-01-01

    In this paper,a two-stage semi-hybrid flowshop problem which appears in graphics processing is studied.For this problem,there are two machines M1 and M2,and a set of independent jobs J={J1,J2,...,Jn}. Each Ji consists of two tasks Ai and Bi,and task Ai must be completed before task Bi can start.Furthermore,task Ai can be processed on M1 for ai time units,or on M2 for ai' time units,while task Bi can only be processed on M2 for bi time units.Jobs and machines are available at time zero and no preemption is allowed.The objective is to minimize the maximum job completion time.It is showed that this problem is NP-hard.And a pseudo-polynomial time optimal algorithm is presented.A polynomial time approximation algorithm with worst-case ratio 2 is also presented.

  15. Preparation and characterization of Cu2ZnSnSe4 thin films grown from ZnSe and Cu2SnS3 precursors in a two stage process

    Science.gov (United States)

    Moreno, R.; Leguizamon, A.; Hurtado, M.; Guzmán, F.; Gordillo, G.

    2014-04-01

    Compound of the kesterite familie has been considered as an alternative absorber layer in the manufacture of thin film solar cells due to its earth abundant and environmental friendly constituents and high absorption coefficient. In this work we propose a new route to grow single phase Cu2ZnSnSe4 (CZTSe) thin films with tetragonal-kesterite type structure; this consist in sequential evaporation of thin films of CuSe, SnSe and ZnSe in a two stage process. Measurements of X-ray diffraction (XRD) revealed the formation of the Cu2ZnSnSe4 compound, grown with tetragonal Kësterite type structure. Optical characterization performed through spectral transmittance measurements established that this compound has high absorption (absorption coefficient > 104 cm-1) and a forbidden energy gap of 1.46 eV; these results indicate that the CZTSe thin films we have prepared has properties suitable for later use as absorber layer in solar cells. Results regarding electrical transport properties determined from temperature dependent conductivity measurements are also reported.

  16. 含钪Al-Zn-Mg-Zr合金双级时效工艺的正交优化%Two-stage Aging Process Orthogonal Optimization of Al-Zn-Mg-Zr Alloy Containing Scandium

    Institute of Scientific and Technical Information of China (English)

    聂俊红; 聂辉文; 潘清林; 韦莉莉

    2016-01-01

    The two-stage aging process optimization was conducted on Al-Zn-Mg-Zr alloy containing 0.25wt% scandium by orthogonal experiment.The influences of the two-stage aging process parameters (pre-aging time and temperature,final-aging time and temperature)on the mechanical properties and electrical conductivity of the alloy were studied and the microstructure of the alloy after treatment by this process was observed.The results show that the influence significance of the factors on the comprehensive performance especially mechanical properties of the alloy was ranked from high to low as follows:final-aging temperature,final-aging time,pre-aging time and pre-aging temperature.The suitable two-step aging process of the alloy was determined as pre-aging at 120 ℃ for 4 h followed by final-aging at 140 ℃ for 12 h.After treated with this process,the tensile strength,yield strength, elongation and electrical conductivity of the alloy was 553 MPa,534 MPa,12.0%,37.3%IACS respectively.Theη′phase and Al3 (Sc,Zr)particles distributed dispersively in the base structure of the alloy,contributing to the improvement the strength and stress corrosion resistance of the alloy.%采用正交试验对含0.25%(质量分数)钪 Al-Zn-Mg-Zr 合金的双级时效进行了工艺优化,研究了双级时效工艺参数(预时效温度和时间、终时效温度和时间)对合金力学性能和电导率的影响,观察了最佳工艺处理后合金的显微组织.结果表明:对该合金综合性能,尤其是力学性能影响程度由大到小的参数依次为终时效温度、终时效时间、预时效时间、预时效温度;该合金适宜的双级时效工艺为120℃×4 h+140℃×12 h,经该工艺处理后,合金的抗拉强度为553 MPa,屈服强度为534 MPa,伸长率为12.0%,电导率为37.3%IACS;合金基体组织中弥散分布着η′相以及Al3(Sc,Zr)粒子,有助于合金强度以及抗应力腐蚀性能的提高.

  17. Stochastic processes - quantum physics

    Energy Technology Data Exchange (ETDEWEB)

    Streit, L. (Bielefeld Univ. (Germany, F.R.))

    1984-01-01

    The author presents an elementary introduction to stochastic processes. He starts from simple quantum mechanics and considers problems in probability, finally presenting quantum dynamics in terms of stochastic processes.

  18. Recovery of Ni and Co from Nickel Laterite with Two Stages Sulphation Roasting-Water Leaching Process%两段硫酸化焙烧—水浸从红土镍矿中回收镍钴

    Institute of Scientific and Technical Information of China (English)

    汪云华; 董海刚; 范兴祥; 吴跃东; 赵家春; 暂林寒; 李柏榆; 李楠

    2012-01-01

    Ni and Co were recovered from an Australia nonferrous nickel laterite by two stages sulpation roasting-water leaching process. The process and conditions was studied. The effects of acid to materials ratio, roasting temperature and time in low roasting action and high roasting action on Ni and Co leaching rate were investigated, respectively. The results show that the sulfation roasting is performed under the conditions of sulfuric acid to materials ratio of 0. 6, first low temperature roasting temperature of 250 ℃ , roasting time of 60 min, second high temperature roasting temperature of 650 ℃, and roasting time of 3 h. The roasted product is subjected to water leaching, and the leaching rate of Ni and Co are up to 93. 38% and 91. 95%, respectively.%以澳大利亚某红土镍矿为原料,采用两段硫酸化焙烧—水浸工艺回收镍钴.重点探讨酸料比、低温焙烧段温度及时间、高温焙烧段温度及时间对镍钴浸出率的影响.结果表明,在酸料比为0.6,一段低温焙烧温度250℃,焙烧时间60 min,二段高温焙烧温度650℃,焙烧时间3h的条件下进行硫酸化焙烧,焙烧产物经过水浸,Ni和Co浸出率分别达到93.38%和91.95%.

  19. Two stage sorption type cryogenic refrigerator including heat regeneration system

    Science.gov (United States)

    Jones, Jack A.; Wen, Liang-Chi; Bard, Steven

    1989-01-01

    A lower stage chemisorption refrigeration system physically and functionally coupled to an upper stage physical adsorption refrigeration system is disclosed. Waste heat generated by the lower stage cycle is regenerated to fuel the upper stage cycle thereby greatly improving the energy efficiency of a two-stage sorption refrigerator. The two stages are joined by disposing a first pressurization chamber providing a high pressure flow of a first refrigerant for the lower stage refrigeration cycle within a second pressurization chamber providing a high pressure flow of a second refrigerant for the upper stage refrigeration cycle. The first pressurization chamber is separated from the second pressurization chamber by a gas-gap thermal switch which at times is filled with a thermoconductive fluid to allow conduction of heat from the first pressurization chamber to the second pressurization chamber.

  20. Two-stage sampling for acceptance testing

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, C.L.; Bryan, M.F.

    1992-09-01

    Sometimes a regulatory requirement or a quality-assurance procedure sets an allowed maximum on a confidence limit for a mean. If the sample mean of the measurements is below the allowed maximum, but the confidence limit is above it, a very widespread practice is to increase the sample size and recalculate the confidence bound. The confidence level of this two-stage procedure is rarely found correctly, but instead is typically taken to be the nominal confidence level, found as if the final sample size had been specified in advance. In typical settings, the correct nominal [alpha] should be between the desired P(Type I error) and half that value. This note gives tables for the correct a to use, some plots of power curves, and an example of correct two-stage sampling.

  1. Two-stage sampling for acceptance testing

    Energy Technology Data Exchange (ETDEWEB)

    Atwood, C.L.; Bryan, M.F.

    1992-09-01

    Sometimes a regulatory requirement or a quality-assurance procedure sets an allowed maximum on a confidence limit for a mean. If the sample mean of the measurements is below the allowed maximum, but the confidence limit is above it, a very widespread practice is to increase the sample size and recalculate the confidence bound. The confidence level of this two-stage procedure is rarely found correctly, but instead is typically taken to be the nominal confidence level, found as if the final sample size had been specified in advance. In typical settings, the correct nominal {alpha} should be between the desired P(Type I error) and half that value. This note gives tables for the correct a to use, some plots of power curves, and an example of correct two-stage sampling.

  2. Two Stage Gear Tooth Dynamics Program

    Science.gov (United States)

    1989-08-01

    cordi - tions and associated iteration prooedure become more complex. This is due to both the increased number of components and to the time for a...solved for each stage in the two stage solution . There are (3 + ntrrber of planets) degrees of freedom fcr eacb stage plus two degrees of freedom...should be devised. It should be noted that this is not minor task. In general, each stage plus an input or output shaft will have 2 times (4 + number

  3. 两级臭氧一活性炭组合工艺净化太湖水中试研究%Pilot Study on Two-stage Ozonization and Activated Carbon Process for Taihu Lake Water Purification

    Institute of Scientific and Technical Information of China (English)

    刘洋; 崔云霞

    2011-01-01

    采用两级臭氧-活性炭组合工艺在以太湖水为水源的某水厂进行深度处理中试研究.结果表明:该组合处理工艺对有机污染物有稳定的去除效果,在预臭氧投加重为0.5 mg/L、主臭氧投加量为0.7 mg/L下,相对于原水对CODMn,UV254(紫外吸光度),DOC,THMEP,氨氮,亚硝酸盐氮和硝酸盐氨的平均去除率分别为47.06%,80%,31.92%,58.9%,65.5%,81.25%和9.1%,出永满足GB 5749-2006《生活饮用水卫生标准》的要求,炭滤池出水中臭氧消毒副产物均低于标准限值,组合工艺对有害物质冲击负荷有一定的抵抗能力.%The pilot experiments were carried out to investigate the advanced treatment by the combined process of two-stage ozonization and activated carbon in a plant using Taihu Lake water as raw water. The results showed that the removal of organic pollutants by the combined process was stable. Relative to the raw water, the average removal rates of CODmns UV254, DOC, THMEP, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen were 47.06%, 80%, 31.92%, 58.9%, 65.3%, 81.25% and 9.1% respectively, when the pre-ozonizaiton dosage was 0.5mg/L and the main ozonization dosage was 0.7mg/L. The effluent could meet "Standards of Drinking Water Quality "(GB 5749-2006). The disinfection by-products of ozone were lower than the standard limit in the effluent from carbon filter. The combined process has some resistibility to the impact load of hazardous substances.

  4. Condensate from a two-stage gasifier

    DEFF Research Database (Denmark)

    Bentzen, Jens Dall; Henriksen, Ulrik Birk; Hindsgaul, Claus

    2000-01-01

    that the organic compounds and the inhibition effect are very low even before treatment with activated carbon. The moderate inhibition effect relates to a high content of ammonia in the condensate. The nitrifiers become tolerant to the condensate after a few weeks of exposure. The level of organic compounds......Condensate, produced when gas from downdraft biomass gasifier is cooled, contains organic compounds that inhibit nitrifiers. Treatment with activated carbon removes most of the organics and makes the condensate far less inhibitory. The condensate from an optimised two-stage gasifier is so clean...

  5. Two Stage Sibling Cycle Compressor/Expander.

    Science.gov (United States)

    1994-02-01

    vol. 5, p. 424. 11. L. Bauwens and M.P. Mitchell, " Regenerator Analysis: Validation of the MS*2 Stirling Cycle Code," Proc. XVIIIth International...PL-TR--94-1051 PL-TR-- 94-1051 TWO STAGE SIBLING CYCLE COMPRESSOR/EXPANDER Matthew P. Mitchell . Mitchell/ Stirling Machines/Systems, Inc. No\\ 1995...ty. THIS PAGE IS UNCLASSIFIED PL-TR-94-1051 This final report was prepared byMitchell/ Stirling Machines/Systems, Inc., Berkeley, CA under Contract

  6. 两段式脱臭过程对大豆油中反式脂肪酸含量的影响%Effect of Two- Stage Deodorizing Process on Content of TransFatty Acid in Soybean Oil

    Institute of Scientific and Technical Information of China (English)

    李振岚; 罗淑年; 史加宁; 冯丽丽; 于殿宇

    2011-01-01

    In this experiment, bleaching vegetable oil was chosen as a raw material, and two - stage deodoriza-tion was obtained by using the external heating method in the process of oil deodorizing. First, deodorizing temperature of the oil reached to 170 ℃ , and the direct steam came into the tray column in order to remove low boiling point materials, including ketone. The water steam pressure was 0.5 Mpa,deodorizing time was 12 min,the consumption of water stream was 1% of oil weight,and residual pressure was 266 Pa. After the preliminary deodorization,the content of trans fatty acid in Soybean Oil was 0.016 %. Then in order to remove high boiling point materials, such as Free fatty acid and hydrocarbon, deodorizing temperature reached to 240 ℃ , deodorizing time was 40 min, the consumption of water stream was 0.5% of oil weight and residual pressure was 266 Pa. The deodorizing time of the oil was greatly shortened at a high temperature,it was unlikely to form trans -fatty acids,and the trans -fatty acids content in the soybean oil was only 0.38%.%本试验以脱色大豆油为原料,采用两段式的脱臭方式,首先将脱色大豆油加热至170℃,通入直接蒸汽脱除油脂中的酮类等低沸点的物质,通入压力为0.5 MPa蒸汽,蒸汽用量为油重的0.3%,脱臭时间为12 min,残压为266Pa,初步脱臭后大豆油中反式脂肪酸的质量分数为0.016%,为了脱除油脂中的游离脂肪酸、烃类等高沸点的物质,将大豆油加热至240℃,蒸汽用量为油重的0.5%,脱臭时间为40 min,残压为266Pa.由于大豆油在高温条件下脱臭时间短,不易形成反式脂肪酸,成品油中反式脂肪酸质量分数仅为0.38%.

  7. Multiphoton Processes and Attosecond Physics

    CERN Document Server

    Midorikawa, Katsumi; 12th International Conference on Multiphoton Processes; 3rd International Conference on Attosecond Physics

    2012-01-01

    Recent advances in ultrashort pulsed laser technology have opened new frontiers in atomic, molecular and optical sciences. The 12th International Conference on Multiphoton Processes (ICOMP12) and the 3rd International Conference on Attosecond Physics (ATTO3), held jointly in Sapporo, Japan, during July 3-8, showcased studies at the forefront of research on multiphoton processes and attosecond physics. This book summarizes presentations and discussions from these two conferences.

  8. Classification in two-stage screening.

    Science.gov (United States)

    Longford, Nicholas T

    2015-11-10

    Decision theory is applied to the problem of setting thresholds in medical screening when it is organised in two stages. In the first stage that involves a less expensive procedure that can be applied on a mass scale, an individual is classified as a negative or a likely positive. In the second stage, the likely positives are subjected to another test that classifies them as (definite) positives or negatives. The second-stage test is more accurate, but also more expensive and more involved, and so there are incentives to restrict its application. Robustness of the method with respect to the parameters, some of which have to be set by elicitation, is assessed by sensitivity analysis.

  9. Two stage gear tooth dynamics program

    Science.gov (United States)

    Boyd, Linda S.

    1989-01-01

    The epicyclic gear dynamics program was expanded to add the option of evaluating the tooth pair dynamics for two epicyclic gear stages with peripheral components. This was a practical extension to the program as multiple gear stages are often used for speed reduction, space, weight, and/or auxiliary units. The option was developed for either stage to be a basic planetary, star, single external-external mesh, or single external-internal mesh. The two stage system allows for modeling of the peripherals with an input mass and shaft, an output mass and shaft, and a connecting shaft. Execution of the initial test case indicated an instability in the solution with the tooth paid loads growing to excessive magnitudes. A procedure to trace the instability is recommended as well as a method of reducing the program's computation time by reducing the number of boundary condition iterations.

  10. Measuring the Learning from Two-Stage Collaborative Group Exams

    CERN Document Server

    Ives, Joss

    2014-01-01

    A two-stage collaborative exam is one in which students first complete the exam individually, and then complete the same or similar exam in collaborative groups immediately afterward. To quantify the learning effect from the group component of these two-stage exams in an introductory Physics course, a randomized crossover design was used where each student participated in both the treatment and control groups. For each of the two two-stage collaborative group midterm exams, questions were designed to form matched near-transfer pairs with questions on an end-of-term diagnostic which was used as a learning test. For learning test questions paired with questions from the first midterm, which took place six to seven weeks before the learning test, an analysis using a mixed-effects logistic regression found no significant differences in learning-test performance between the control and treatment group. For learning test questions paired with questions from the second midterm, which took place one to two weeks prio...

  11. Square Kilometre Array station configuration using two-stage beamforming

    CERN Document Server

    Jiwani, Aziz; Razavi-Ghods, Nima; Hall, Peter J; Padhi, Shantanu; de Vaate, Jan Geralt bij

    2012-01-01

    The lowest frequency band (70 - 450 MHz) of the Square Kilometre Array will consist of sparse aperture arrays grouped into geographically-localised patches, or stations. Signals from thousands of antennas in each station will be beamformed to produce station beams which form the inputs for the central correlator. Two-stage beamforming within stations can reduce SKA-low signal processing load and costs, but has not been previously explored for the irregular station layouts now favoured in radio astronomy arrays. This paper illustrates the effects of two-stage beamforming on sidelobes and effective area, for two representative station layouts (regular and irregular gridded tile on an irregular station). The performance is compared with a single-stage, irregular station. The inner sidelobe levels do not change significantly between layouts, but the more distant sidelobes are affected by the tile layouts; regular tile creates diffuse, but regular, grating lobes. With very sparse arrays, the station effective area...

  12. Two-Stage Modelling Of Random Phenomena

    Science.gov (United States)

    Barańska, Anna

    2015-12-01

    The main objective of this publication was to present a two-stage algorithm of modelling random phenomena, based on multidimensional function modelling, on the example of modelling the real estate market for the purpose of real estate valuation and estimation of model parameters of foundations vertical displacements. The first stage of the presented algorithm includes a selection of a suitable form of the function model. In the classical algorithms, based on function modelling, prediction of the dependent variable is its value obtained directly from the model. The better the model reflects a relationship between the independent variables and their effect on the dependent variable, the more reliable is the model value. In this paper, an algorithm has been proposed which comprises adjustment of the value obtained from the model with a random correction determined from the residuals of the model for these cases which, in a separate analysis, were considered to be the most similar to the object for which we want to model the dependent variable. The effect of applying the developed quantitative procedures for calculating the corrections and qualitative methods to assess the similarity on the final outcome of the prediction and its accuracy, was examined by statistical methods, mainly using appropriate parametric tests of significance. The idea of the presented algorithm has been designed so as to approximate the value of the dependent variable of the studied phenomenon to its value in reality and, at the same time, to have it "smoothed out" by a well fitted modelling function.

  13. Physical processes in protoplanetary disks

    CERN Document Server

    Armitage, Philip J

    2015-01-01

    This review introduces physical processes in protoplanetary disks relevant to accretion and the initial stages of planet formation. After reprising the elementary theory of disk structure and evolution, I discuss the gas-phase physics of angular momentum transport through turbulence and disk winds, and how this may be related to episodic accretion observed in Young Stellar Objects. Turning to solids, I review the evolution of single particles under aerodynamic forces, and describe the conditions necessary for the development of collective gas-particle instabilities. Observations show that disks are not always radially smooth axisymmetric structures, and I discuss how gas and particle processes can interact to form observable large-scale structure (at ice lines, vortices and in zonal flows). I conclude with disk dispersal.

  14. Two-Stage Aggregate Formation via Streams in Myxobacteria

    Science.gov (United States)

    Alber, Mark; Kiskowski, Maria; Jiang, Yi

    2005-03-01

    In response to adverse conditions, myxobacteria form aggregates which develop into fruiting bodies. We model myxobacteria aggregation with a lattice cell model based entirely on short range (non-chemotactic) cell-cell interactions. Local rules result in a two-stage process of aggregation mediated by transient streams. Aggregates resemble those observed in experiment and are stable against even very large perturbations. Noise in individual cell behavior increases the effects of streams and result in larger, more stable aggregates. Phys. Rev. Lett. 93: 068301 (2004).

  15. Two-Stage Eagle Strategy with Differential Evolution

    CERN Document Server

    Yang, Xin-She

    2012-01-01

    Efficiency of an optimization process is largely determined by the search algorithm and its fundamental characteristics. In a given optimization, a single type of algorithm is used in most applications. In this paper, we will investigate the Eagle Strategy recently developed for global optimization, which uses a two-stage strategy by combing two different algorithms to improve the overall search efficiency. We will discuss this strategy with differential evolution and then evaluate their performance by solving real-world optimization problems such as pressure vessel and speed reducer design. Results suggest that we can reduce the computing effort by a factor of up to 10 in many applications.

  16. Composite likelihood and two-stage estimation in family studies

    DEFF Research Database (Denmark)

    Andersen, Elisabeth Anne Wreford

    2002-01-01

    Composite likelihood; Two-stage estimation; Family studies; Copula; Optimal weights; All possible pairs......Composite likelihood; Two-stage estimation; Family studies; Copula; Optimal weights; All possible pairs...

  17. Preemptive scheduling in a two-stage supply chain to minimize the makespan

    NARCIS (Netherlands)

    Pei, Jun; Fan, Wenjuan; Pardalos, Panos M.; Liu, Xinbao; Goldengorin, Boris; Yang, Shanlin

    2015-01-01

    This paper deals with the problem of preemptive scheduling in a two-stage supply chain framework. The supply chain environment contains two stages: production and transportation. In the production stage jobs are processed on a manufacturer's bounded serial batching machine, preemptions are allowed,

  18. On the robustness of two-stage estimators

    KAUST Repository

    Zhelonkin, Mikhail

    2012-04-01

    The aim of this note is to provide a general framework for the analysis of the robustness properties of a broad class of two-stage models. We derive the influence function, the change-of-variance function, and the asymptotic variance of a general two-stage M-estimator, and provide their interpretations. We illustrate our results in the case of the two-stage maximum likelihood estimator and the two-stage least squares estimator. © 2011.

  19. Two-stage perceptual learning to break visual crowding.

    Science.gov (United States)

    Zhu, Ziyun; Fan, Zhenzhi; Fang, Fang

    2016-01-01

    When a target is presented with nearby flankers in the peripheral visual field, it becomes harder to identify, which is referred to as crowding. Crowding sets a fundamental limit of object recognition in peripheral vision, preventing us from fully appreciating cluttered visual scenes. We trained adult human subjects on a crowded orientation discrimination task and investigated whether crowding could be completely eliminated by training. We discovered a two-stage learning process with this training task. In the early stage, when the target and flankers were separated beyond a certain distance, subjects acquired a relatively general ability to break crowding, as evidenced by the fact that the breaking of crowding could transfer to another crowded orientation, even a crowded motion stimulus, although the transfer to the opposite visual hemi-field was weak. In the late stage, like many classical perceptual learning effects, subjects' performance gradually improved and showed specificity to the trained orientation. We also found that, when the target and flankers were spaced too finely, training could only reduce, rather than completely eliminate, the crowding effect. This two-stage learning process illustrates a learning strategy for our brain to deal with the notoriously difficult problem of identifying peripheral objects in clutter. The brain first learned to solve the "easy and general" part of the problem (i.e., improving the processing resolution and segmenting the target and flankers) and then tackle the "difficult and specific" part (i.e., refining the representation of the target).

  20. Effect of ammoniacal nitrogen on one-stage and two-stage anaerobic digestion of food waste

    Energy Technology Data Exchange (ETDEWEB)

    Ariunbaatar, Javkhlan, E-mail: jaka@unicas.it [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Scotto Di Perta, Ester [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy); Panico, Antonio [Telematic University PEGASO, Piazza Trieste e Trento, 48, 80132 Naples (Italy); Frunzo, Luigi [Department of Mathematics and Applications Renato Caccioppoli, University of Naples Federico II, Via Claudio, 21, 80125 Naples (Italy); Esposito, Giovanni [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); Lens, Piet N.L. [UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Pirozzi, Francesco [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy)

    2015-04-15

    Highlights: • Almost 100% of the biomethane potential of food waste was recovered during AD in a two-stage CSTR. • Recirculation of the liquid fraction of the digestate provided the necessary buffer in the AD reactors. • A higher OLR (0.9 gVS/L·d) led to higher accumulation of TAN, which caused more toxicity. • A two-stage reactor is more sensitive to elevated concentrations of ammonia. • The IC{sub 50} of TAN for the AD of food waste amounts to 3.8 g/L. - Abstract: This research compares the operation of one-stage and two-stage anaerobic continuously stirred tank reactor (CSTR) systems fed semi-continuously with food waste. The main purpose was to investigate the effects of ammoniacal nitrogen on the anaerobic digestion process. The two-stage system gave more reliable operation compared to one-stage due to: (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; and (iii) a higher conversion rate of organic substrate to biomethane. Also a small amount of biohydrogen was detected from the first stage of the two-stage reactor making this system attractive for biohythane production. As the digestate contains ammoniacal nitrogen, re-circulating it provided the necessary alkalinity in the systems, thus preventing an eventual failure by volatile fatty acids (VFA) accumulation. However, re-circulation also resulted in an ammonium accumulation, yielding a lower biomethane production. Based on the batch experimental results the 50% inhibitory concentration of total ammoniacal nitrogen on the methanogenic activities was calculated as 3.8 g/L, corresponding to 146 mg/L free ammonia for the inoculum used for this research. The two-stage system was affected by the inhibition more than the one-stage system, as it requires less alkalinity and the physically separated methanogens are more sensitive to inhibitory factors, such as ammonium and propionic acid.

  1. Space plasma physics stationary processes

    CERN Document Server

    Hasegawa, Akira

    1989-01-01

    During the 30 years of space exploration, important discoveries in the near-earth environment such as the Van Allen belts, the plasmapause, the magnetotail and the bow shock, to name a few, have been made. Coupling between the solar wind and the magnetosphere and energy transfer processes between them are being identified. Space physics is clearly approaching a new era, where the emphasis is being shifted from discoveries to understanding. One way of identifying the new direction may be found in the recent contribution of atmospheric science and oceanography to the development of fluid dynamics. Hydrodynamics is a branch of classical physics in which important discoveries have been made in the era of Rayleigh, Taylor, Kelvin and Helmholtz. However, recent progress in global measurements using man-made satellites and in large scale computer simulations carried out by scientists in the fields of atmospheric science and oceanography have created new activities in hydrodynamics and produced important new discover...

  2. Two stage treatment of dairy effluent using immobilized Chlorella pyrenoidosa.

    Science.gov (United States)

    Yadavalli, Rajasri; Heggers, Goutham Rao Venkata Naga

    2013-12-19

    Dairy effluents contains high organic load and unscrupulous discharge of these effluents into aquatic bodies is a matter of serious concern besides deteriorating their water quality. Whilst physico-chemical treatment is the common mode of treatment, immobilized microalgae can be potentially employed to treat high organic content which offer numerous benefits along with waste water treatment. A novel low cost two stage treatment was employed for the complete treatment of dairy effluent. The first stage consists of treating the diary effluent in a photobioreactor (1 L) using immobilized Chlorella pyrenoidosa while the second stage involves a two column sand bed filtration technique. Whilst NH4+-N was completely removed, a 98% removal of PO43--P was achieved within 96 h of two stage purification processes. The filtrate was tested for toxicity and no mortality was observed in the zebra fish which was used as a model at the end of 96 h bioassay. Moreover, a significant decrease in biological oxygen demand and chemical oxygen demand was achieved by this novel method. Also the biomass separated was tested as a biofertilizer to the rice seeds and a 30% increase in terms of length of root and shoot was observed after the addition of biomass to the rice plants. We conclude that the two stage treatment of dairy effluent is highly effective in removal of BOD and COD besides nutrients like nitrates and phosphates. The treatment also helps in discharging treated waste water safely into the receiving water bodies since it is non toxic for aquatic life. Further, the algal biomass separated after first stage of treatment was highly capable of increasing the growth of rice plants because of nitrogen fixation ability of the green alga and offers a great potential as a biofertilizer.

  3. Golographic interferometry of physical processes

    Science.gov (United States)

    Ostrovskaya, G. V.

    2016-06-01

    This paper is devoted to the contribution of Yuri Ostrovsky to holographic interferometry, one of the fundamental scientific and practical applications of holography. The title of this paper is the same as the title of his doctoral thesis that he defended in 1974, and, as it seems to me, reflects most of the specific features of the majority of his scientific publications, viz., an inseparable link of the methods developed by him with the results obtained with the help of these methods in a wide range of investigations of physical processes and phenomena.

  4. 联合两段氧化制合成气/F-T合成的GTL工艺和催化剂%An Integrated Process of a Two-Stage Fixed Bed Syngas Production and F-T Synthesis for GTL in Remote Gas Field

    Institute of Scientific and Technical Information of China (English)

    代小平; 余长春; 李强; 张长斌; 江启滢; 沈师孔

    2003-01-01

    A novel process for catalytic oxidation of methane to synthesis gas (syngas), which consists of twoconsecutive fixed-bed reactors with air introduced into the reactors, integrated Fischer-Tropsch synthesis, was inves-tigated. At the same time, a catalytic combustion technology has been investigated for utilizing the F-T offgas togenerate heat or power energy. The results show that the two-stage fixed reactor process keep away from explosionof CH4/O2. The integrated process is fitted to produce diesel oil and lubricating oil in remote gas field.

  5. Stochastic processes in chemical physics

    CERN Document Server

    Shuler, K E

    2009-01-01

    The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

  6. Development of two-stage grain grinder

    Directory of Open Access Journals (Sweden)

    V. N. Trubnikov

    2016-01-01

    Full Text Available The most important task in the development of the diet of farm animals feeding is a selection of the most balanced in its composition and most nutritious feeds, which are safe and meet all the necessary requirements at the same time. To evaluate the productive value of feeds and their effectiveness the rate of food productive action η was proposed. This ratio reflects the productive part of the total value of the exchange energy of the daily feed ration and is an essential criterion of the feed quality indicators. In the feed rations of animals the most expensive, but energy-rich feed is a mixed fodder, a mixture of grinded seeds of agricultural crops and protein, mineral and vitamin additives. In the diet for its nutritional value, this feed product is for cattle – 50, pigs – 60… 100 and birds – 100%. The basic operation in the production of mixed fodder is seeds grinding, i.e. their destruction under the influence of external forces, exceeding the forces of molecular adhesion of the grains particles. To grind the grain different ways are used: chopping, grinding, impact «in flight», crushing, etc. In the production of mixed fodder on the existing production equipment, there is the problem of getting the grain mixed fodder the necessary degree of grinding and uniform in its particle size distribution at the same time. When receiving too coarse grinding there is a problem of difficult digestibility of mixed fodder by farm animals. Moreover grinding process is accompanied by a high energy consumption. Grain grinder, the principle of which is based on the implementation of two ways of grinding grain: splitting and impact «in flight» is proposed. The proposed constructive solutions allow to obtain a high-performance technical means for crushing seeds of crops, as well as reduce energy costs that arise during the course of the process of obtaining of mixed fodder. The methodology justification of degree of grain grinding by

  7. A Two-Stage Waste Gasification Reactor for Mars In-Situ Resource Utilization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design, build, and test a two-stage waste processing reactor for space applications. Our proposed technology converts waste from space missions into...

  8. Two Stage Assessment of Thermal Hazard in An Underground Mine

    Science.gov (United States)

    Drenda, Jan; Sułkowski, Józef; Pach, Grzegorz; Różański, Zenon; Wrona, Paweł

    2016-06-01

    The results of research into the application of selected thermal indices of men's work and climate indices in a two stage assessment of climatic work conditions in underground mines have been presented in this article. The difference between these two kinds of indices was pointed out during the project entitled "The recruiting requirements for miners working in hot underground mine environments". The project was coordinated by The Institute of Mining Technologies at Silesian University of Technology. It was a part of a Polish strategic project: "Improvement of safety in mines" being financed by the National Centre of Research and Development. Climate indices are based only on physical parameters of air and their measurements. Thermal indices include additional factors which are strictly connected with work, e.g. thermal resistance of clothing, kind of work etc. Special emphasis has been put on the following indices - substitute Silesian temperature (TS) which is considered as the climatic index, and the thermal discomfort index (δ) which belongs to the thermal indices group. The possibility of the two stage application of these indices has been taken into consideration (preliminary and detailed estimation). Based on the examples it was proved that by the application of thermal hazard (detailed estimation) it is possible to avoid the use of additional technical solutions which would be necessary to reduce thermal hazard in particular work places according to the climate index. The threshold limit value for TS has been set, based on these results. It was shown that below TS = 24°C it is not necessary to perform detailed estimation.

  9. 甲烷氧化制合成气两段反应新工艺%A Novel Process of Two-Stage Reactor for Catalytic Oxidation of Methane to Syngas

    Institute of Scientific and Technical Information of China (English)

    沈师孔; 潘智勇; 董朝阳; 江启滢; 余长春

    2000-01-01

    @@ Interest in conversion of natural gas to liquid hydrocarbons (GTL) by Fischer-Tropsch synthesis has grown significantly over the last decade. Most research and development work has focused on syngas production step, which accounts for more than 50% of the total investment. Reducing the cost of syngas production would have great beneficial effects on GTL process. Catalytic partial oxidation of methane (CPOM) to syngas is a slightly exothermic, highly selective, and energy efficient process. It gives syngas with n(H2)/n(CO)=2, directly suitable for F-T synthesis. However, CPOM process has not yet been used commercially. The major engineering problems are the high temperature gradient and the risk of explosion with premixed CH4-O2 mixture, which is within the ignition and explosion limit. In fluidized-bed reactors, the heat transfer is much better, which ensures a more uniform temperature and safer operation. A technology for syngas production by contacting CH4 with limited amount of steam and O2 in a fluidized-bed reactor has been developed[1].

  10. Two-stage combustion of coal in a pressurized fluidized bed combustor for use in gas turbine processes; Zweistufige Verbrennung von Kohlen in einer Druckwirbelschichtanlage fuer den Einsatz in Gasturbinenprozessen

    Energy Technology Data Exchange (ETDEWEB)

    Mieden, M.; Bonn, B.; Baumann, H.

    1996-12-31

    The power raising efficiencies of PFBC-processes depend on the temperature of the flue-gas at the entrance of gas-turbines. In order to rise efficiencies, hybrid combined cycles have been suggested in which the gas temperature increased e.g. by firing natural gas in an afterburner at the entrance of the turbine. Alternatively a fuel gas can be produced by gasifying coal in a carboniser or gasifier. This fuel gas can be used to heat up the flue gas of the PFBC to a temperature that ensures an optimum gas-turbine efficiency. A process has been examined at DMT that provides a fuel gas with high CO concentration by substoichiometric combustion of coal in a PFBC. In order to increase the gas temperature the fuel gas is mixed with oxygen in an afterburner and then burns spontaneously. The experiments showed that it was possible to reach a temperature of about 1300 C in the afterburner. As the laboratory scale PFBC plant is provided with flue gas recirculation, equilibrium calculations have been made to examine the feasibility of the process for operation with air. (orig.) [Deutsch] Fuer die Erhoehung des Wirkungsgrades von druckwirbelschichtgefeuerten Kombiprozessen durch die Temperaturerhoehung im Eingang der Gasturbine wurde ein neuartiges Verfahren mit extrem gestufter Verbrennung der Kohle untersucht. Durch unterstoechiometrische Verbrennung von Kohle in einem Druckwirbelschichtreaktor (p=5 bar; T=900 C) wird zunaechst ein stark CO-haltiges Gas erzeugt, das nach der Entstaubung durch Vermischung mit Sauerstoff in einer zweiten Stufe, die als Nachbrennkammer diente, ausgebrannt wurde. Dabei erhoehte sich die Temperatur des Rauchgases, und es wurden Temperaturen von ueber 1300 C erreicht. Bei Sauerstoffzahlen von minimal {lambda}=0,75 betrugen die CO-Konzentrationen des Schwachgases der ersten Stufe bis zu 14%. Der Sauerstoffmangel fuehrte dazu, dass auch unverbrannter Kohlenstoff aus der Druckwirbelschicht ausgetragen wurde und in die Nachbrennkammer gelangte. Bei den

  11. Experiment research on two-stage dry-fed entrained flow coal gasifier

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The process flow and the main devices of a new two-stage dry-fed coal gasification pilot plant with a throughout of 36 t/d are introduced in this paper. For comparison with the traditional one-stage gasifiers, the influences of the coal feed ratio between two stages on the performance of the gasifier are detailedly studied by a series of experiments. The results reveal that the two-stage gasification decreases the temperature of the syngas at the outlet of the gasifier, simplifies the gasification process, and reduces the size of the syngas cooler. Moreover, the cold gas efficiency of the gasifier can be improved by using the two-stage gasification. In our experiments, the efficiency is about 3%-6% higher than the existing one-stage gasifiers.

  12. Two-Stage Conversion of Land and Marine Biomass for Biogas and Biohydrogen Production

    OpenAIRE

    Nkemka, Valentine

    2012-01-01

    The replacement of fossil fuels by renewable fuels such as biogas and biohydrogen will require efficient and economically competitive process technologies together with new kinds of biomass. A two-stage system for biogas production has several advantages over the widely used one-stage continuous stirred tank reactor (CSTR). However, it has not yet been widely implemented on a large scale. Biohydrogen can be produced in the anaerobic two-stage system. It is considered to be a useful fuel for t...

  13. 乳清两步发酵法制取环保型融雪剂醋酸钙镁盐%Production of environment friendly deicer calcium magnesium acetate by two-stage fermentation process from cheese whey

    Institute of Scientific and Technical Information of China (English)

    韩爱霞; 吕海棠; 王兆谦; 任彦蓉; 王海鹏; 郗怡佳; 黄靖; 李春花

    2012-01-01

    To reasonably utilize cheese whey which was a by-product from the manufacture of cheese and casein,the anaerobic fermentation process was developed to produce acetic acid from lactose in cheese whey .Then environment friendly deicers calcium magnesium acetate (CMA) can be produced with the acetic acid and CaO/MgO.A lactobacillus plantarum was used to convert lactose in cheese whey to lactic acid in the first stage,the conversion rate of lactic acid was 47.47%. Propionibac-terium was used to convert lactic acid to acetic acid and propionic acid which could be separated by gas chromatography method in the second stage,and the conversion rate of acetic acid was 5.643%.Structure of CMA was verified by IR.This method effectively utilized cheese whey and reduced production costs of calcium magnesium acetate, will have a bright future.%为合理利用乳酪和乳酪素的副产品乳清,研究了一种新的厌氧发酵方法将乳清中的乳糖发酵成醋酸,以此醋酸与CaO/MgO反应制备得到环保型融雪剂醋酸钙镁盐(CMA).第一步用植物乳杆菌将乳清中的乳糖发酵成乳酸,乳酸的转化率是47.47%;第二步用丙酸杆菌将乳酸发酵成醋酸与丙酸,用气相色谱法将二者分离,得到醋酸的转化率为5.643%;用红外光谱法验证了此醋酸与CaO/MgO反应制备得到的CMA的结构.该法既有效地利用了乳酪和乳酪素的副产品乳清,又降低了环保型融雪剂醋酸钙镁盐的生产成本,具有很好的应用前景.

  14. Residential Two-Stage Gas Furnaces - Do They Save Energy?

    Energy Technology Data Exchange (ETDEWEB)

    Lekov, Alex; Franco, Victor; Lutz, James

    2006-05-12

    Residential two-stage gas furnaces account for almost a quarter of the total number of models listed in the March 2005 GAMA directory of equipment certified for sale in the United States. Two-stage furnaces are expanding their presence in the market mostly because they meet consumer expectations for improved comfort. Currently, the U.S. Department of Energy (DOE) test procedure serves as the method for reporting furnace total fuel and electricity consumption under laboratory conditions. In 2006, American Society of Heating Refrigeration and Air-conditioning Engineers (ASHRAE) proposed an update to its test procedure which corrects some of the discrepancies found in the DOE test procedure and provides an improved methodology for calculating the energy consumption of two-stage furnaces. The objectives of this paper are to explore the differences in the methods for calculating two-stage residential gas furnace energy consumption in the DOE test procedure and in the 2006 ASHRAE test procedure and to compare test results to research results from field tests. Overall, the DOE test procedure shows a reduction in the total site energy consumption of about 3 percent for two-stage compared to single-stage furnaces at the same efficiency level. In contrast, the 2006 ASHRAE test procedure shows almost no difference in the total site energy consumption. The 2006 ASHRAE test procedure appears to provide a better methodology for calculating the energy consumption of two-stage furnaces. The results indicate that, although two-stage technology by itself does not save site energy, the combination of two-stage furnaces with BPM motors provides electricity savings, which are confirmed by field studies.

  15. Two-stage local M-estimation of additive models

    Institute of Scientific and Technical Information of China (English)

    JIANG JianCheng; LI JianTao

    2008-01-01

    This paper studies local M-estimation of the nonparametric components of additive models. A two-stage local M-estimation procedure is proposed for estimating the additive components and their derivatives. Under very mild conditions, the proposed estimators of each additive component and its derivative are jointly asymptotically normal and share the same asymptotic distributions as they would be if the other components were known. The established asymptotic results also hold for two particular local M-estimations: the local least squares and least absolute deviation estimations. However,for general two-stage local M-estimation with continuous and nonlinear ψ-functions, its implementation is time-consuming. To reduce the computational burden, one-step approximations to the two-stage local M-estimators are developed. The one-step estimators are shown to achieve the same efficiency as the fully iterative two-stage local M-estimators, which makes the two-stage local M-estimation more feasible in practice. The proposed estimators inherit the advantages and at the same time overcome the disadvantages of the local least-squares based smoothers. In addition, the practical implementation of the proposed estimation is considered in details. Simulations demonstrate the merits of the two-stage local M-estimation, and a real example illustrates the performance of the methodology.

  16. Two-stage local M-estimation of additive models

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper studies local M-estimation of the nonparametric components of additive models.A two-stage local M-estimation procedure is proposed for estimating the additive components and their derivatives.Under very mild conditions,the proposed estimators of each additive component and its derivative are jointly asymptotically normal and share the same asymptotic distributions as they would be if the other components were known.The established asymptotic results also hold for two particular local M-estimations:the local least squares and least absolute deviation estimations.However,for general two-stage local M-estimation with continuous and nonlinear ψ-functions,its implementation is time-consuming.To reduce the computational burden,one-step approximations to the two-stage local M-estimators are developed.The one-step estimators are shown to achieve the same effciency as the fully iterative two-stage local M-estimators,which makes the two-stage local M-estimation more feasible in practice.The proposed estimators inherit the advantages and at the same time overcome the disadvantages of the local least-squares based smoothers.In addition,the practical implementation of the proposed estimation is considered in details.Simulations demonstrate the merits of the two-stage local M-estimation,and a real example illustrates the performance of the methodology.

  17. Processing multidimensional nuclear physics data

    Energy Technology Data Exchange (ETDEWEB)

    Becker, J. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    Modern Ge detector arrays for gamma-ray spectroscopy are producing data sets unprecedented in size and event multiplicity. Gammasphere, the DOE sponsored array, has the following characteristics: (1) High granularity (110 detectors); (2) High efficiency (10%); and (3) Precision energy measurements (Delta EE = 0.2%). Characteristics of detector line shape, the data set, and the standard practice in the nuclear physics community to the nuclear gamma-ray cascades from the 4096 times 4096 times 4096 data cube will be discussed.

  18. Effect of Silica Fume on two-stage Concrete Strength

    Science.gov (United States)

    Abdelgader, H. S.; El-Baden, A. S.

    2015-11-01

    Two-stage concrete (TSC) is an innovative concrete that does not require vibration for placing and compaction. TSC is a simple concept; it is made using the same basic constituents as traditional concrete: cement, coarse aggregate, sand and water as well as mineral and chemical admixtures. As its name suggests, it is produced through a two-stage process. Firstly washed coarse aggregate is placed into the formwork in-situ. Later a specifically designed self compacting grout is introduced into the form from the lowest point under gravity pressure to fill the voids, cementing the aggregate into a monolith. The hardened concrete is dense, homogeneous and has in general improved engineering properties and durability. This paper presents the results from a research work attempt to study the effect of silica fume (SF) and superplasticizers admixtures (SP) on compressive and tensile strength of TSC using various combinations of water to cement ratio (w/c) and cement to sand ratio (c/s). Thirty six concrete mixes with different grout constituents were tested. From each mix twenty four standard cylinder samples of size (150mm×300mm) of concrete containing crushed aggregate were produced. The tested samples were made from combinations of w/c equal to: 0.45, 0.55 and 0.85, and three c/s of values: 0.5, 1 and 1.5. Silica fume was added at a dosage of 6% of weight of cement, while superplasticizer was added at a dosage of 2% of cement weight. Results indicated that both tensile and compressive strength of TSC can be statistically derived as a function of w/c and c/s with good correlation coefficients. The basic principle of traditional concrete, which says that an increase in water/cement ratio will lead to a reduction in compressive strength, was shown to hold true for TSC specimens tested. Using a combination of both silica fume and superplasticisers caused a significant increase in strength relative to control mixes.

  19. A continuous two stage solar coal gasification system

    Science.gov (United States)

    Mathur, V. K.; Breault, R. W.; Lakshmanan, S.; Manasse, F. K.; Venkataramanan, V.

    The characteristics of a two-stage fluidized-bed hybrid coal gasification system to produce syngas from coal, lignite, and peat are described. Devolatilization heat of 823 K is supplied by recirculating gas heated by a solar receiver/coal heater. A second-stage gasifier maintained at 1227 K serves to crack remaining tar and light oil to yield a product free from tar and other condensables, and sulfur can be removed by hot clean-up processes. CO is minimized because the coal is not burned with oxygen, and the product gas contains 50% H2. Bench scale reactors consist of a stage I unit 0.1 m in diam which is fed coal 200 microns in size. A stage II reactor has an inner diam of 0.36 m and serves to gasify the char from stage I. A solar power source of 10 kWt is required for the bench model, and will be obtained from a central receiver with quartz or heat pipe configurations for heat transfer.

  20. Physical Processes Controlling Earth's Climate

    Science.gov (United States)

    Genio, Anthony Del

    2013-01-01

    As background for consideration of the climates of the other terrestrial planets in our solar system and the potential habitability of rocky exoplanets, we discuss the basic physics that controls the Earths present climate, with particular emphasis on the energy and water cycles. We define several dimensionless parameters relevant to characterizing a planets general circulation, climate and hydrological cycle. We also consider issues associated with the use of past climate variations as indicators of future anthropogenically forced climate change, and recent advances in understanding projections of future climate that might have implications for Earth-like exoplanets.

  1. Dynamical processes in atomic and molecular physics

    CERN Document Server

    Ogurtsov, Gennadi

    2012-01-01

    Atomic and molecular physics underlie a basis for our knowledge of fundamental processes in nature and technology and in such applications as solid state physics, chemistry and biology. In recent years, atomic and molecular physics has undergone a revolutionary change due to great achievements in computing and experimental techniques. As a result, it has become possible to obtain information both on atomic and molecular characteristics and on dynamics of atomic and molecular processes. This e-book highlights the present state of investigations in the field of atomic and molecular physics. Rece

  2. A two-stage ethanol-based biodiesel production in a packed bed reactor

    DEFF Research Database (Denmark)

    Xu, Yuan; Nordblad, Mathias; Woodley, John

    2012-01-01

    A two-stage enzymatic process for producing fatty acid ethyl ester (FAEE) in a packed bed reactor is reported. The process uses an experimental immobilized lipase (NS 88001) and Novozym 435 to catalyze transesterification (first stage) and esterification (second stage), respectively. Both stages...

  3. Two-stage, dilute sulfuric acid hydrolysis of wood : an investigation of fundamentals

    Science.gov (United States)

    John F. Harris; Andrew J. Baker; Anthony H. Conner; Thomas W. Jeffries; James L. Minor; Roger C. Pettersen; Ralph W. Scott; Edward L Springer; Theodore H. Wegner; John I. Zerbe

    1985-01-01

    This paper presents a fundamental analysis of the processing steps in the production of methanol from southern red oak (Quercus falcata Michx.) by two-stage dilute sulfuric acid hydrolysis. Data for hemicellulose and cellulose hydrolysis are correlated using models. This information is used to develop and evaluate a process design.

  4. Macroscopic flame structure in a premixed-spray burner. 1st Report. formation and disappearance processes of droplet clusters and two-stage flame structure; Yokongo funmu kaen no kyoshiteki nensho kyodo. 1. Yuteki cluster no keisei shoshitsu katei to niju kaen kozo

    Energy Technology Data Exchange (ETDEWEB)

    Tsushima, S.; Saito, H.; Akamatsu, F.; Katsuki, M. [Osaka University, Osaka (Japan)

    2000-08-25

    In an attempt to elucidate formation and disappearance processes of droplet clusters in spray flames, simultaneous measurements consisting of laser tomography and flame chemiluminescence detection are applied to a premixed-spay burner. The smart combination of measurements provides time-series data-set serving for better understanding of spray flames, which essentially contains inhomogeneity in space and time. It is revealed that referential flame propagation through a premixed-spray stream plays a significant role in creating droplet clusters and that droplet clusters formed in this manner evanesces from their outer boundaries. Those observation confirms that the premixed-spray flame comprises both premixed-mode flame in upstream region and diffusion-mode flame in downstream region, respectively, i.e, two-stage flame structure previously reported for spray flames stabilized in either counter or stagnation flows. (author)

  5. STARS A Two Stage High Gain Harmonic Generation FEL Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    M. Abo-Bakr; W. Anders; J. Bahrdt; P. Budz; K.B. Buerkmann-Gehrlein; O. Dressler; H.A. Duerr; V. Duerr; W. Eberhardt; S. Eisebitt; J. Feikes; R. Follath; A. Gaupp; R. Goergen; K. Goldammer; S.C. Hessler; K. Holldack; E. Jaeschke; Thorsten Kamps; S. Klauke; J. Knobloch; O. Kugeler; B.C. Kuske; P. Kuske; A. Meseck; R. Mitzner; R. Mueller; M. Neeb; A. Neumann; K. Ott; D. Pfluckhahn; T. Quast; M. Scheer; Th. Schroeter; M. Schuster; F. Senf; G. Wuestefeld; D. Kramer; Frank Marhauser

    2007-08-01

    BESSY is proposing a demonstration facility, called STARS, for a two-stage high-gain harmonic generation free electron laser (HGHG FEL). STARS is planned for lasing in the wavelength range 40 to 70 nm, requiring a beam energy of 325 MeV. The facility consists of a normal conducting gun, three superconducting TESLA-type acceleration modules modified for CW operation, a single stage bunch compressor and finally a two-stage HGHG cascaded FEL. This paper describes the faciliy layout and the rationale behind the operation parameters.

  6. Physical Processes of Interstellar Turbulence

    CERN Document Server

    Vazquez-Semadeni, Enrique

    2012-01-01

    I discuss the role of self-gravity and radiative heating and cooling in shaping the nature of the turbulence in the interstellar medium (ISM) of our galaxy. The heating and cooling cause it to be highly compressible, and, in some regimes of density and temperature, to become thermally unstable, tending to spontaneously segregate into warm/diffuse and cold/dense phases. On the other hand, turbulence is an inherently mixing process, tending to replenish the density and temperature ranges that would be forbidden under thermal processes alone. The turbulence in the ionized ISM appears to be transonic (i.e, with Mach numbers $\\Ms \\sim 1$), and thus to behave essentially incompressibly. However, in the neutral medium, thermal instability causes the sound speed of the gas to fluctuate by up to factors of $\\sim 30$, and thus the flow can be highly supersonic with respect to the dense/cold gas, although numerical simulations suggest that this behavior corresponds more to the ensemble of cold clumps than to the clumps'...

  7. Two-stage data envelopment analysis technique for evaluating internal supply chain efficiency

    Directory of Open Access Journals (Sweden)

    Nisakorn Somsuk

    2014-12-01

    Full Text Available A two-stage data envelopment analysis (DEA which uses mathematical linear programming techniques is applied to evaluate the efficiency of a system composed of two relational sub-processes, by which the outputs from the first sub-process (as the intermediate outputs of the system are the inputs for the second sub-process. The relative efficiencies of the system and its sub-processes can be measured by applying the two-stage DEA. According to the literature review on the supply chain management, this technique can be used as a tool for evaluating the efficiency of the supply chain composed of two relational sub-processes. The technique can help to determine the inefficient sub-processes. Once the inefficient sub-process was improved its efficiency, it would result in better aggregate efficiency of the supply chain. This paper aims to present a procedure for evaluating the efficiency of the supply chain by using the two-stage DEA, under the assumption of constant returns to scale, with an example of internal supply chain efficiency measurement of insurance companies by applying the two-stage DEA for illustration. Moreover, in this paper the authors also present some observations on the application of this technique.

  8. Soil physical land degradation processes

    Science.gov (United States)

    Horn, Rainer

    2017-04-01

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

  9. Physical processes in the Indian seas

    Digital Repository Service at National Institute of Oceanography (India)

    Swamy, G.N.; Das, V.K.; Antony, M.K.

    The proceedings volume comprise 38 papers covering air-sea boundary problems, open-ocean dynamics, nearshore processes, observational and analysis techniques, etc. This volume helps in taking stock of physical oceanographic activities in India...

  10. Two-Stage Fuzzy Portfolio Selection Problem with Transaction Costs

    Directory of Open Access Journals (Sweden)

    Yanju Chen

    2015-01-01

    Full Text Available This paper studies a two-period portfolio selection problem. The problem is formulated as a two-stage fuzzy portfolio selection model with transaction costs, in which the future returns of risky security are characterized by possibility distributions. The objective of the proposed model is to achieve the maximum utility in terms of the expected value and variance of the final wealth. Given the first-stage decision vector and a realization of fuzzy return, the optimal value expression of the second-stage programming problem is derived. As a result, the proposed two-stage model is equivalent to a single-stage model, and the analytical optimal solution of the two-stage model is obtained, which helps us to discuss the properties of the optimal solution. Finally, some numerical experiments are performed to demonstrate the new modeling idea and the effectiveness. The computational results provided by the proposed model show that the more risk-averse investor will invest more wealth in the risk-free security. They also show that the optimal invested amount in risky security increases as the risk-free return decreases and the optimal utility increases as the risk-free return increases, whereas the optimal utility increases as the transaction costs decrease. In most instances the utilities provided by the proposed two-stage model are larger than those provided by the single-stage model.

  11. Efficient Two-Stage Group Testing Algorithms for DNA Screening

    CERN Document Server

    Huber, Michael

    2011-01-01

    Group testing algorithms are very useful tools for DNA library screening. Building on recent work by Levenshtein (2003) and Tonchev (2008), we construct in this paper new infinite classes of combinatorial structures, the existence of which are essential for attaining the minimum number of individual tests at the second stage of a two-stage disjunctive testing algorithm.

  12. FREE GRAFT TWO-STAGE URETHROPLASTY FOR HYPOSPADIAS REPAIR

    Institute of Scientific and Technical Information of China (English)

    Zhong-jin Yue; Ling-jun Zuo; Jia-ji Wang; Gan-ping Zhong; Jian-ming Duan; Zhi-ping Wang; Da-shan Qin

    2005-01-01

    Objective To evaluate the effectiveness of free graft transplantation two-stage urethroplasty for hypospadias repair.Methods Fifty-eight cases with different types of hypospadias including 10 subcoronal, 36 penile shaft, 9 scrotal, and 3 perineal were treated with free full-thickness skin graft or (and) buccal mucosal graft transplantation two-stage urethroplasty. Of 58 cases, 45 were new cases, 13 had history of previous failed surgeries. Operative procedure included two stages: the first stage is to correct penile curvature (chordee), prepare transplanting bed, harvest and prepare full-thickness skin graft, buccal mucosal graft, and perform graft transplantation. The second stage is to complete urethroplasty and glanuloplasty.Results After the first stage operation, 56 of 58 cases (96.6%) were successful with grafts healing well, another 2foreskin grafts got gangrened. After the second stage operation on 56 cases, 5 cases failed with newly formed urethras opened due to infection, 8 cases had fistulas, 43 (76.8%) cases healed well.Conclusions Free graft transplantation two-stage urethroplasty for hypospadias repair is a kind of effective treatment with broad indication, comparatively high success rate, less complicationsand good cosmatic results, indicative of various types of hypospadias repair.

  13. Composite likelihood and two-stage estimation in family studies

    DEFF Research Database (Denmark)

    Andersen, Elisabeth Anne Wreford

    2004-01-01

    In this paper register based family studies provide the motivation for linking a two-stage estimation procedure in copula models for multivariate failure time data with a composite likelihood approach. The asymptotic properties of the estimators in both parametric and semi-parametric models are d...

  14. A two-stage rank test using density estimation

    NARCIS (Netherlands)

    Albers, Willem/Wim

    1995-01-01

    For the one-sample problem, a two-stage rank test is derived which realizes a required power against a given local alternative, for all sufficiently smooth underlying distributions. This is achieved using asymptotic expansions resulting in a precision of orderm −1, wherem is the size of the first

  15. The construction of customized two-stage tests

    NARCIS (Netherlands)

    Adema, Jos J.

    1990-01-01

    In this paper mixed integer linear programming models for customizing two-stage tests are given. Model constraints are imposed with respect to test composition, administration time, inter-item dependencies, and other practical considerations. It is not difficult to modify the models to make them use

  16. Accuracy of the One-Stage and Two-Stage Impression Techniques: A Comparative Analysis

    Directory of Open Access Journals (Sweden)

    Ladan Jamshidy

    2016-01-01

    Full Text Available Introduction. One of the main steps of impression is the selection and preparation of an appropriate tray. Hence, the present study aimed to analyze and compare the accuracy of one- and two-stage impression techniques. Materials and Methods. A resin laboratory-made model, as the first molar, was prepared by standard method for full crowns with processed preparation finish line of 1 mm depth and convergence angle of 3-4°. Impression was made 20 times with one-stage technique and 20 times with two-stage technique using an appropriate tray. To measure the marginal gap, the distance between the restoration margin and preparation finish line of plaster dies was vertically determined in mid mesial, distal, buccal, and lingual (MDBL regions by a stereomicroscope using a standard method. Results. The results of independent test showed that the mean value of the marginal gap obtained by one-stage impression technique was higher than that of two-stage impression technique. Further, there was no significant difference between one- and two-stage impression techniques in mid buccal region, but a significant difference was reported between the two impression techniques in MDL regions and in general. Conclusion. The findings of the present study indicated higher accuracy for two-stage impression technique than for the one-stage impression technique.

  17. Effects of earthworm casts and zeolite on the two-stage composting of green waste.

    Science.gov (United States)

    Zhang, Lu; Sun, Xiangyang

    2015-05-01

    Because it helps protect the environment and encourages economic development, composting has become a viable method for organic waste disposal. The objective of this study was to investigate the effects of earthworm casts (EWCs) (at 0.0%, 0.30%, and 0.60%) and zeolite (clinoptilolite, CL) (at 0%, 15%, and 25%) on the two-stage composting of green waste. The combination of EWCs and CL improved the conditions of the composting process and the quality of the compost products in terms of the thermophilic phase, humification, nitrification, microbial numbers and enzyme activities, the degradation of cellulose and hemicellulose, and physico-chemical characteristics and nutrient contents of final composts. The compost matured in only 21days with the optimized two-stage composting method rather than in the 90-270days required for traditional composting. The optimal two-stage composting and the best quality compost were obtained with 0.30% EWCs and 25% CL.

  18. Capacity Analysis of Two-Stage Production lines with Many Products

    NARCIS (Netherlands)

    M.B.M. de Koster (René)

    1987-01-01

    textabstractWe consider two-stage production lines with an intermediate buffer. A buffer is needed when fluctuations occur. For single-product production lines fluctuations in capacity availability may be caused by random processing times, failures and random repair times. For multi-product producti

  19. Physical and mathematical modelling of extrusion processes

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Gronostajski, Z.; Niechajowics, A.

    2000-01-01

    The main objective of the work is to study the extrusion process using physical modelling and to compare the findings of the study with finite element predictions. The possibilities and advantages of the simultaneous application of both of these methods for the analysis of metal forming processes...

  20. Physical and mathematical modelling of extrusion processes

    DEFF Research Database (Denmark)

    Arentoft, Mogens; Gronostajski, Z.; Niechajowics, A.

    2000-01-01

    The main objective of the work is to study the extrusion process using physical modelling and to compare the findings of the study with finite element predictions. The possibilities and advantages of the simultaneous application of both of these methods for the analysis of metal forming processes...

  1. Recursive algorithm for the two-stage EFOP estimation method

    Institute of Scientific and Technical Information of China (English)

    LUO GuiMing; HUANG Jian

    2008-01-01

    A recursive algorithm for the two-stage empirical frequency-domain optimal param-eter (EFOP) estimation method Was proposed. The EFOP method was a novel sys-tem identificallon method for Black-box models that combines time-domain esti-mation and frequency-domain estimation. It has improved anti-disturbance perfor-mance, and could precisely identify models with fewer sample numbers. The two-stage EFOP method based on the boot-strap technique was generally suitable for Black-box models, but it was an iterative method and takes too much computation work so that it did not work well online. A recursive algorithm was proposed for dis-turbed stochastic systems. Some simulation examples are included to demonstrate the validity of the new method.

  2. Two-stage approach to full Chinese parsing

    Institute of Scientific and Technical Information of China (English)

    Cao Hailong; Zhao Tiejun; Yang Muyun; Li Sheng

    2005-01-01

    Natural language parsing is a task of great importance and extreme difficulty. In this paper, we present a full Chinese parsing system based on a two-stage approach. Rather than identifying all phrases by a uniform model, we utilize a divide and conquer strategy. We propose an effective and fast method based on Markov model to identify the base phrases. Then we make the first attempt to extend one of the best English parsing models i.e. the head-driven model to recognize Chinese complex phrases. Our two-stage approach is superior to the uniform approach in two aspects. First, it creates synergy between the Markov model and the head-driven model. Second, it reduces the complexity of full Chinese parsing and makes the parsing system space and time efficient. We evaluate our approach in PARSEVAL measures on the open test set, the parsing system performances at 87.53% precision, 87.95% recall.

  3. Thermal design of two-stage evaporative cooler based on thermal comfort criterion

    Science.gov (United States)

    Gilani, Neda; Poshtiri, Amin Haghighi

    2017-04-01

    Performance of two-stage evaporative coolers at various outdoor air conditions was numerically studied, and its geometric and physical characteristics were obtained based on thermal comfort criteria. For this purpose, a mathematical model was developed based on conservation equations of mass, momentum and energy to determine heat and mass transfer characteristics of the system. The results showed that two-stage indirect/direct cooler can provide the thermal comfort condition when outdoor air temperature and relative humidity are located in the range of 34-54 °C and 10-60 %, respectively. Moreover, as relative humidity of the ambient air rises, two-stage evaporative cooler with the smaller direct and larger indirect cooler will be needed. In building with high cooling demand, thermal comfort may be achieved at a greater air change per hour number, and thus an expensive two-stage evaporative cooler with a higher electricity consumption would be required. Finally, a design guideline was proposed to determine the size of required plate heat exchangers at various operating conditions.

  4. Thermal design of two-stage evaporative cooler based on thermal comfort criterion

    Science.gov (United States)

    Gilani, Neda; Poshtiri, Amin Haghighi

    2016-09-01

    Performance of two-stage evaporative coolers at various outdoor air conditions was numerically studied, and its geometric and physical characteristics were obtained based on thermal comfort criteria. For this purpose, a mathematical model was developed based on conservation equations of mass, momentum and energy to determine heat and mass transfer characteristics of the system. The results showed that two-stage indirect/direct cooler can provide the thermal comfort condition when outdoor air temperature and relative humidity are located in the range of 34-54 °C and 10-60 %, respectively. Moreover, as relative humidity of the ambient air rises, two-stage evaporative cooler with the smaller direct and larger indirect cooler will be needed. In building with high cooling demand, thermal comfort may be achieved at a greater air change per hour number, and thus an expensive two-stage evaporative cooler with a higher electricity consumption would be required. Finally, a design guideline was proposed to determine the size of required plate heat exchangers at various operating conditions.

  5. Income and Poverty across SMSAs: A Two-Stage Analysis

    OpenAIRE

    1993-01-01

    Two popular explanations of urban poverty are the "welfare-disincentive" and "urban-deindustrialization" theories. Using cross-sectional Census data, we develop a two-stage model to predict an SMSAs median family income and poverty rate. The model allows the city's welfare level and industrial structure to affect its median family income and poverty rate directly. It also allows welfare and industrial structure to affect income and poverty indirectly, through their effects on family structure...

  6. A Two-stage Polynomial Method for Spectrum Emissivity Modeling

    OpenAIRE

    Qiu, Qirong; Liu, Shi; Teng, Jing; Yan, Yong

    2015-01-01

    Spectral emissivity is a key in the temperature measurement by radiation methods, but not easy to determine in a combustion environment, due to the interrelated influence of temperature and wave length of the radiation. In multi-wavelength radiation thermometry, knowing the spectral emissivity of the material is a prerequisite. However in many circumstances such a property is a complex function of temperature and wavelength and reliable models are yet to be sought. In this study, a two stages...

  7. Physical activity (PA) and the disablement process

    DEFF Research Database (Denmark)

    Schultz-Larsen, Kirsten; Rahmanfard, Naghmeh; Holst, Claus

    2012-01-01

    . Among older women, the association between RPA and incidence of disability was attenuated in analyses that controlled for baseline mobility function. Thus, the association between physical activity and mortality reflected processes different from those underlying a simple relation between physical...... activity, disability and mortality. Physical activity was an ubiquitous predictor of longevity, but only for women....... community-living persons, aged 75-83 years, we evaluated the 1021 who reported no disability in basic activities of daily living. Participants were followed for a median of 8.34 years in public registers to determine onset of disability and mortality. RPA predicted mortality in older women (HR=1.77, 95%CI=1...

  8. Physical processes in the interstellar medium

    CERN Document Server

    Spitzer, Lyman

    2008-01-01

    Physical Processes in the Interstellar Medium discusses the nature of interstellar matter, with a strong emphasis on basic physical principles, and summarizes the present state of knowledge about the interstellar medium by providing the latest observational data. Physics and chemistry of the interstellar medium are treated, with frequent references to observational results. The overall equilibrium and dynamical state of the interstellar gas are described, with discussions of explosions produced by star birth and star death and the initial phases of cloud collapse leading to star formation.

  9. 难浸含砷金精矿两段生物氧化—氰化提金工艺试验研究%Study on the two-stage biooxidation-cyanidation process in leaching refractory arsenious gold concentrates

    Institute of Scientific and Technical Information of China (English)

    郑艳平; 祁玉海; 赵禧民

    2013-01-01

    某难浸含砷金精矿中金矿物嵌布粒度极细,有92.00%呈次显微金(不可见)的形式存在,且金矿物嵌存状态以包裹金为主,占94.58%.对金精矿进行常规氰化浸出,金的浸出率仅为3.41%.通过采用两段生物氧化预处理—氰化提金工艺,金的浸出率提高到95.02%,比常规氰化提高了91.61%.%The dissemination of gold mineral existing in the refractory arsenious gold concentrates is so fine that there are 92. 00 % of them taking the form of submicroscopic gold( not visible) ,and 94. 58 % of them are embedded inclusion gold. Conventional cyanide leaching of the concentrates only achieves a leaching rate of 3. 41 %. However, gold leaching rate can reach 95. 02 % after applying the two-stage biooxidation-cyanidation process, which is 91. 61% higher than conventional cyanide leaching process.

  10. Overcoming the bottlenecks of anaerobic digestion of olive mill solid waste by two-stage fermentation.

    Science.gov (United States)

    Stoyanova, Elitza; Lundaa, Tserennyam; Bochmann, Günther; Fuchs, Werner

    2017-02-01

    Two-stage anaerobic digestion (AD) of two-phase olive mill solid waste (OMSW) was applied for reducing the inhibiting factors by optimizing the acidification stage. Single-stage AD and co-fermentation with chicken manure were conducted coinstantaneous for direct comparison. Degradation of the polyphenols up to 61% was observed during the methanogenic stage. Nevertheless the concentration of phenolic substances was still high; the two-stage fermentation remained stable at OLR 1.5 kgVS/m³day. The buffer capacity of the system was twice as high, compared to the one-stage fermentation, without additives. The two-stage AD was a combined process - thermophilic first stage and mesophilic second stage, which pointed out to be the most profitable for AD of OMSW for the reduced hydraulic retention time (HRT) from 230 to 150 days, and three times faster than the single-stage and the co-fermentation start-up of the fermentation. The optimal HRT and incubation temperature for the first stage were determined to four days and 55°C. The performance of the two-stage AD concerning the stability of the process was followed by the co-digestion of OMSW with chicken manure as a nitrogen-rich co-substrate, which makes them viable options for waste disposal with concomitant energy recovery.

  11. Treatment of corn ethanol distillery wastewater using two-stage anaerobic digestion.

    Science.gov (United States)

    Ráduly, B; Gyenge, L; Szilveszter, Sz; Kedves, A; Crognale, S

    In this study the mesophilic two-stage anaerobic digestion (AD) of corn bioethanol distillery wastewater is investigated in laboratory-scale reactors. Two-stage AD technology separates the different sub-processes of the AD in two distinct reactors, enabling the use of optimal conditions for the different microbial consortia involved in the different process phases, and thus allowing for higher applicable organic loading rates (OLRs), shorter hydraulic retention times (HRTs) and better conversion rates of the organic matter, as well as higher methane content of the produced biogas. In our experiments the reactors have been operated in semi-continuous phase-separated mode. A specific methane production of 1,092 mL/(L·d) has been reached at an OLR of 6.5 g TCOD/(L·d) (TCOD: total chemical oxygen demand) and a total HRT of 21 days (5.7 days in the first-stage, and 15.3 days in the second-stage reactor). Nonetheless the methane concentration in the second-stage reactor was very high (78.9%); the two-stage AD outperformed the reference single-stage AD (conducted at the same reactor loading rate and retention time) by only a small margin in terms of volumetric methane production rate. This makes questionable whether the higher methane content of the biogas counterbalances the added complexity of the two-stage digestion.

  12. Predictive Modeling of a Two-Stage Gearbox towards Fault Detection

    Directory of Open Access Journals (Sweden)

    Edward J. Diehl

    2016-01-01

    Full Text Available This paper presents a systematic approach to the modeling and analysis of a benchmark two-stage gearbox test bed to characterize gear fault signatures when processed with harmonic wavelet transform (HWT analysis. The eventual goal of condition monitoring is to be able to interpret vibration signals from nonstationary machinery in order to identify the type and severity of gear damage. To advance towards this goal, a lumped-parameter model that can be analyzed efficiently is developed which characterizes the gearbox vibratory response at the system level. The model parameters are identified through correlated numerical and experimental investigations. The model fidelity is validated first by spectrum analysis, using constant speed experimental data, and secondly by HWT analysis, using nonstationary experimental data. Model prediction and experimental data are compared for healthy gear operation and a seeded fault gear with a missing tooth. The comparison confirms that both the frequency content and the predicted, relative response magnitudes match with physical measurements. The research demonstrates that the modeling method in combination with the HWT data analysis has the potential for facilitating successful fault detection and diagnosis for gearbox systems.

  13. Forty-five-degree two-stage venous cannula: advantages over standard two-stage venous cannulation.

    Science.gov (United States)

    Lawrence, D R; Desai, J B

    1997-01-01

    We present a 45-degree two-stage venous cannula that confers advantage to the surgeon using cardiopulmonary bypass. This cannula exits the mediastinum under the transverse bar of the sternal retractor, leaving the rostral end of the sternal incision free of apparatus. It allows for lifting of the heart with minimal effect on venous return and does not interfere with the radially laid out sutures of an aortic valve replacement using an interrupted suture technique.

  14. Statistical Physics for Natural Language Processing

    CERN Document Server

    Moreno, Juan-Manuel Torres; SanJuan, Eric

    2010-01-01

    In this paper we study the {\\sc Enertex} model that has been applied to fundamental tasks in Natural Language Processing (NLP) including automatic document summarization and topic segmentation. The model is language independent. It is based on the intuitive concept of Textual Energy, inspired by Neural Networks and Statistical Physics of magnetic systems. It can be implemented using simple matrix operations and on the contrary of PageRank algorithms, it avoids any iterative process.

  15. On Two-stage Seamless Adaptive Design in Clinical Trials

    Directory of Open Access Journals (Sweden)

    Shein-Chung Chow

    2008-12-01

    Full Text Available In recent years, the use of adaptive design methods in clinical research and development based on accrued data has become very popular because of its efficiency and flexibility in modifying trial and/or statistical procedures of ongoing clinical trials. One of the most commonly considered adaptive designs is probably a two-stage seamless adaptive trial design that combines two separate studies into one single study. In many cases, study endpoints considered in a two-stage seamless adaptive design may be similar but different (e.g. a biomarker versus a regular clinical endpoint or the same study endpoint with different treatment durations. In this case, it is important to determine how the data collected from both stages should be combined for the final analysis. It is also of interest to know how the sample size calculation/allocation should be done for achieving the study objectives originally set for the two stages (separate studies. In this article, formulas for sample size calculation/allocation are derived for cases in which the study endpoints are continuous, discrete (e.g. binary responses, and contain time-to-event data assuming that there is a well-established relationship between the study endpoints at different stages, and that the study objectives at different stages are the same. In cases in which the study objectives at different stages are different (e.g. dose finding at the first stage and efficacy confirmation at the second stage and when there is a shift in patient population caused by protocol amendments, the derived test statistics and formulas for sample size calculation and allocation are necessarily modified for controlling the overall type I error at the prespecified level.

  16. Space plasma physics: I - Stationary processes

    Science.gov (United States)

    Hasegawa, Akira; Sato, Tetsuya

    1989-01-01

    The physics of stationary processes in space plasmas is examined theoretically in an introduction intended for graduate students. The approach involves the extensive use of numerical simulations. Chapters are devoted to fundamental principles, small-amplitude waves, and the stationary solar plasma system; typical measurement data and simulation results are presented graphically.

  17. Two-stage series array SQUID amplifier for space applications

    Science.gov (United States)

    Tuttle, J. G.; DiPirro, M. J.; Shirron, P. J.; Welty, R. P.; Radparvar, M.

    We present test results for a two-stage integrated SQUID amplifier which uses a series array of d.c. SQUIDS to amplify the signal from a single input SQUID. The device was developed by Welty and Martinis at NIST and recent versions have been manufactured by HYPRES, Inc. Shielding and filtering techniques were employed during the testing to minimize the external noise. Energy resolution of 300 h was demonstrated using a d.c. excitation at frequencies above 1 kHz, and better than 500 h resolution was typical down to 300 Hz.

  18. A Two Stage Classification Approach for Handwritten Devanagari Characters

    CERN Document Server

    Arora, Sandhya; Nasipuri, Mita; Malik, Latesh

    2010-01-01

    The paper presents a two stage classification approach for handwritten devanagari characters The first stage is using structural properties like shirorekha, spine in character and second stage exploits some intersection features of characters which are fed to a feedforward neural network. Simple histogram based method does not work for finding shirorekha, vertical bar (Spine) in handwritten devnagari characters. So we designed a differential distance based technique to find a near straight line for shirorekha and spine. This approach has been tested for 50000 samples and we got 89.12% success

  19. Straw Gasification in a Two-Stage Gasifier

    DEFF Research Database (Denmark)

    Bentzen, Jens Dall; Hindsgaul, Claus; Henriksen, Ulrik Birk

    2002-01-01

    Additive-prepared straw pellets were gasified in the 100 kW two-stage gasifier at The Department of Mechanical Engineering of the Technical University of Denmark (DTU). The fixed bed temperature range was 800-1000°C. In order to avoid bed sintering, as observed earlier with straw gasification...... residues were examined after the test. No agglomeration or sintering was observed in the ash residues. The tar content was measured both by solid phase amino adsorption (SPA) method and cold trapping (Petersen method). Both showed low tar contents (~42 mg/Nm3 without gas cleaning). The particle content...

  20. Two-Stage Fan I: Aerodynamic and Mechanical Design

    Science.gov (United States)

    Messenger, H. E.; Kennedy, E. E.

    1972-01-01

    A two-stage, highly-loaded fan was designed to deliver an overall pressure ratio of 2.8 with an adiabatic efficiency of 83.9 percent. At the first rotor inlet, design flow per unit annulus area is 42 lbm/sec/sq ft (205 kg/sec/sq m), hub/tip ratio is 0.4 with a tip diameter of 31 inches (0.787 m), and design tip speed is 1450 ft/sec (441.96 m/sec). Other features include use of multiple-circular-arc airfoils, resettable stators, and split casings over the rotor tip sections for casing treatment tests.

  1. Optimisation of two-stage screw expanders for waste heat recovery applications

    Science.gov (United States)

    Read, M. G.; Smith, I. K.; Stosic, N.

    2015-08-01

    It has previously been shown that the use of two-phase screw expanders in power generation cycles can achieve an increase in the utilisation of available energy from a low temperature heat source when compared with more conventional single-phase turbines. However, screw expander efficiencies are more sensitive to expansion volume ratio than turbines, and this increases as the expander inlet vapour dryness fraction decreases. For singlestage screw machines with low inlet dryness, this can lead to under expansion of the working fluid and low isentropic efficiency for the expansion process. The performance of the cycle can potentially be improved by using a two-stage expander, consisting of a low pressure machine and a smaller high pressure machine connected in series. By expanding the working fluid over two stages, the built-in volume ratios of the two machines can be selected to provide a better match with the overall expansion process, thereby increasing efficiency for particular inlet and discharge conditions. The mass flow rate though both stages must however be matched, and the compromise between increasing efficiency and maximising power output must also be considered. This research uses a rigorous thermodynamic screw machine model to compare the performance of single and two-stage expanders over a range of operating conditions. The model allows optimisation of the required intermediate pressure in the two- stage expander, along with the rotational speed and built-in volume ratio of both screw machine stages. The results allow the two-stage machine to be fully specified in order to achieve maximum efficiency for a required power output.

  2. Runway Operations Planning: A Two-Stage Heuristic Algorithm

    Science.gov (United States)

    Anagnostakis, Ioannis; Clarke, John-Paul

    2003-01-01

    The airport runway is a scarce resource that must be shared by different runway operations (arrivals, departures and runway crossings). Given the possible sequences of runway events, careful Runway Operations Planning (ROP) is required if runway utilization is to be maximized. From the perspective of departures, ROP solutions are aircraft departure schedules developed by optimally allocating runway time for departures given the time required for arrivals and crossings. In addition to the obvious objective of maximizing throughput, other objectives, such as guaranteeing fairness and minimizing environmental impact, can also be incorporated into the ROP solution subject to constraints introduced by Air Traffic Control (ATC) procedures. This paper introduces a two stage heuristic algorithm for solving the Runway Operations Planning (ROP) problem. In the first stage, sequences of departure class slots and runway crossings slots are generated and ranked based on departure runway throughput under stochastic conditions. In the second stage, the departure class slots are populated with specific flights from the pool of available aircraft, by solving an integer program with a Branch & Bound algorithm implementation. Preliminary results from this implementation of the two-stage algorithm on real-world traffic data are presented.

  3. Two-Stage Heuristic Algorithm for Aircraft Recovery Problem

    Directory of Open Access Journals (Sweden)

    Cheng Zhang

    2017-01-01

    Full Text Available This study focuses on the aircraft recovery problem (ARP. In real-life operations, disruptions always cause schedule failures and make airlines suffer from great loss. Therefore, the main objective of the aircraft recovery problem is to minimize the total recovery cost and solve the problem within reasonable runtimes. An aircraft recovery model (ARM is proposed herein to formulate the ARP and use feasible line of flights as the basic variables in the model. We define the feasible line of flights (LOFs as a sequence of flights flown by an aircraft within one day. The number of LOFs exponentially grows with the number of flights. Hence, a two-stage heuristic is proposed to reduce the problem scale. The algorithm integrates a heuristic scoring procedure with an aggregated aircraft recovery model (AARM to preselect LOFs. The approach is tested on five real-life test scenarios. The computational results show that the proposed model provides a good formulation of the problem and can be solved within reasonable runtimes with the proposed methodology. The two-stage heuristic significantly reduces the number of LOFs after each stage and finally reduces the number of variables and constraints in the aircraft recovery model.

  4. Introduction to quantum physics and information processing

    CERN Document Server

    Vathsan, Radhika

    2016-01-01

    An Elementary Guide to the State of the Art in the Quantum Information FieldIntroduction to Quantum Physics and Information Processing guides beginners in understanding the current state of research in the novel, interdisciplinary area of quantum information. Suitable for undergraduate and beginning graduate students in physics, mathematics, or engineering, the book goes deep into issues of quantum theory without raising the technical level too much.The text begins with the basics of quantum mechanics required to understand how two-level systems are used as qubits. It goes on to show how quant

  5. Analysis of physical processes via imaging vectors

    Science.gov (United States)

    Volovodenko, V.; Efremova, N.; Efremov, V.

    2016-06-01

    Practically, all modeling processes in one way or another are random. The foremost formulated theoretical foundation embraces Markov processes, being represented in different forms. Markov processes are characterized as a random process that undergoes transitions from one state to another on a state space, whereas the probability distribution of the next state depends only on the current state and not on the sequence of events that preceded it. In the Markov processes the proposition (model) of the future by no means changes in the event of the expansion and/or strong information progression relative to preceding time. Basically, modeling physical fields involves process changing in time, i.e. non-stationay processes. In this case, the application of Laplace transformation provides unjustified description complications. Transition to other possibilities results in explicit simplification. The method of imaging vectors renders constructive mathematical models and necessary transition in the modeling process and analysis itself. The flexibility of the model itself using polynomial basis leads to the possible rapid transition of the mathematical model and further analysis acceleration. It should be noted that the mathematical description permits operator representation. Conversely, operator representation of the structures, algorithms and data processing procedures significantly improve the flexibility of the modeling process.

  6. Development of a Novel Type Catalyst SY-2 for Two-Stage Hydrogenation of Pyrolysis Gasoline

    Institute of Scientific and Technical Information of China (English)

    Wu Linmei; Zhang Xuejun; Zhang Zhihua; Wang Fucun

    2004-01-01

    By using the group ⅢB or groupⅦB metals and modulating the characteristics of electric charges on carrier surface, improving the catalyst preparation process and techniques for loading the active metal components, a novel type SY-2 catalyst earmarked for two-stage hydrogenation of pyrolysis gasoline has been developed. The catalyst evaluation results have indicated that the novel catalyst is characterized by a better hydrogenation reaction activity to give higher aromatic yield.

  7. Two-Stage Part-Based Pedestrian Detection

    DEFF Research Database (Denmark)

    Møgelmose, Andreas; Prioletti, Antonio; Trivedi, Mohan M.

    2012-01-01

    Detecting pedestrians is still a challenging task for automotive vision system due the extreme variability of targets, lighting conditions, occlusions, and high speed vehicle motion. A lot of research has been focused on this problem in the last 10 years and detectors based on classifiers has...... gained a special place among the different approaches presented. This work presents a state-of-the-art pedestrian detection system based on a two stages classifier. Candidates are extracted with a Haar cascade classifier trained with the DaimlerDB dataset and then validated through part-based HOG...... of several metrics, such as detection rate, false positives per hour, and frame rate. The novelty of this system rely in the combination of HOG part-based approach, tracking based on specific optimized feature and porting on a real prototype....

  8. A two-stage method for inverse medium scattering

    KAUST Repository

    Ito, Kazufumi

    2013-03-01

    We present a novel numerical method to the time-harmonic inverse medium scattering problem of recovering the refractive index from noisy near-field scattered data. The approach consists of two stages, one pruning step of detecting the scatterer support, and one resolution enhancing step with nonsmooth mixed regularization. The first step is strictly direct and of sampling type, and it faithfully detects the scatterer support. The second step is an innovative application of nonsmooth mixed regularization, and it accurately resolves the scatterer size as well as intensities. The nonsmooth model can be efficiently solved by a semi-smooth Newton-type method. Numerical results for two- and three-dimensional examples indicate that the new approach is accurate, computationally efficient, and robust with respect to data noise. © 2012 Elsevier Inc.

  9. Laparoscopic management of a two staged gall bladdertorsion

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Gall bladder torsion (GBT) is a relatively uncommonentity and rarely diagnosed preoperatively. A constantfactor in all occurrences of GBT is a freely mobilegall bladder due to congenital or acquired anomalies.GBT is commonly observed in elderly white females.We report a 77-year-old, Caucasian lady who wasoriginally diagnosed as gall bladder perforation butwas eventually found with a two staged torsion of thegall bladder with twisting of the Riedel's lobe (partof tongue like projection of liver segment 4A). Thistogether, has not been reported in literature, to thebest of our knowledge. We performed laparoscopiccholecystectomy and she had an uneventful postoperativeperiod. GBT may create a diagnostic dilemmain the context of acute cholecystitis. Timely diagnosisand intervention is necessary, with extra care whileoperating as the anatomy is generally distorted. Thefundus first approach can be useful due to alteredanatomy in the region of Calot's triangle. Laparoscopiccholecystectomy has the benefit of early recovery.

  10. TWO-STAGE OCCLUDED OBJECT RECOGNITION METHOD FOR MICROASSEMBLY

    Institute of Scientific and Technical Information of China (English)

    WANG Huaming; ZHU Jianying

    2007-01-01

    A two-stage object recognition algorithm with the presence of occlusion is presented for microassembly. Coarse localization determines whether template is in image or not and approximately where it is, and fine localization gives its accurate position. In coarse localization, local feature, which is invariant to translation, rotation and occlusion, is used to form signatures. By comparing signature of template with that of image, approximate transformation parameter from template to image is obtained, which is used as initial parameter value for fine localization. An objective function, which is a function of transformation parameter, is constructed in fine localization and minimized to realize sub-pixel localization accuracy. The occluded pixels are not taken into account in objective function, so the localization accuracy will not be influenced by the occlusion.

  11. Two-stage designs for cross-over bioequivalence trials.

    Science.gov (United States)

    Kieser, Meinhard; Rauch, Geraldine

    2015-07-20

    The topic of applying two-stage designs in the field of bioequivalence studies has recently gained attention in the literature and in regulatory guidelines. While there exists some methodological research on the application of group sequential designs in bioequivalence studies, implementation of adaptive approaches has focused up to now on superiority and non-inferiority trials. Especially, no comparison of the features and performance characteristics of these designs has been performed, and therefore, the question of which design to employ in this setting remains open. In this paper, we discuss and compare 'classical' group sequential designs and three types of adaptive designs that offer the option of mid-course sample size recalculation. A comprehensive simulation study demonstrates that group sequential designs can be identified, which show power characteristics that are similar to those of the adaptive designs but require a lower average sample size. The methods are illustrated with a real bioequivalence study example.

  12. The hybrid two stage anticlockwise cycle for ecological energy conversion

    Directory of Open Access Journals (Sweden)

    Cyklis Piotr

    2016-01-01

    Full Text Available The anticlockwise cycle is commonly used for refrigeration, air conditioning and heat pumps applications. The application of refrigerant in the compression cycle is within the temperature limits of the triple point and the critical point. New refrigerants such as 1234yf or 1234ze have many disadvantages, therefore natural refrigerants application is favourable. The carbon dioxide and water can be applied only in the hybrid two stages cycle. The possibilities of this solutions are shown for refrigerating applications, as well some experimental results of the adsorption-compression double stages cycle, powered with solar collectors are shown. As a high temperature cycle the adsorption system is applied. The low temperature cycle is the compression stage with carbon dioxide as a working fluid. This allows to achieve relatively high COP for low temperature cycle and for the whole system.

  13. Continuous removal of endocrine disruptors by versatile peroxidase using a two-stage system.

    Science.gov (United States)

    Taboada-Puig, Roberto; Lu-Chau, Thelmo A; Eibes, Gemma; Feijoo, Gumersindo; Moreira, Maria T; Lema, Juan M

    2015-01-01

    The oxidant Mn(3+) -malonate, generated by the ligninolytic enzyme versatile peroxidase in a two-stage system, was used for the continuous removal of endocrine disrupting compounds (EDCs) from synthetic and real wastewaters. One plasticizer (bisphenol-A), one bactericide (triclosan) and three estrogenic compounds (estrone, 17β-estradiol, and 17α-ethinylestradiol) were removed from wastewater at degradation rates in the range of 28-58 µg/L·min, with low enzyme inactivation. First, the optimization of three main parameters affecting the generation of Mn(3+) -malonate (hydraulic retention time as well as Na-malonate and H2 O2 feeding rates) was conducted following a response surface methodology (RSM). Under optimal conditions, the degradation of the EDCs was proven at high (1.3-8.8 mg/L) and environmental (1.2-6.1 µg/L) concentrations. Finally, when the two-stage system was compared with a conventional enzymatic membrane reactor (EMR) using the same enzyme, a 14-fold increase of the removal efficiency was observed. At the same time, operational problems found during EDCs removal in the EMR system (e.g., clogging of the membrane and enzyme inactivation) were avoided by physically separating the stages of complex formation and pollutant oxidation, allowing the system to be operated for a longer period (∼8 h). This study demonstrates the feasibility of the two-stage enzymatic system for removing EDCs both at high and environmental concentrations.

  14. Thermodynamically reversible processes in statistical physics

    Science.gov (United States)

    Norton, John D.

    2017-02-01

    Equilibrium states are used as limit states to define thermodynamically reversible processes. When these processes are understood in terms of statistical physics, these limit states can change with time due to thermal fluctuations. For macroscopic systems, the changes are insignificant on ordinary time scales and what little change there is can be suppressed by macroscopically negligible, entropy-creating dissipation. For systems of molecular sizes, the changes are large on short time scales. They can only sometimes be suppressed with significant entropy-creating dissipation, and this entropy creation is unavoidable if any process is to proceed to completion. As a result, at molecular scales, thermodynamically reversible processes are impossible in principle. Unlike the macroscopic case, they cannot be realized even approximately when we account for all sources of dissipation, and argumentation invoking them on molecular scales can lead to spurious conclusions.

  15. PHYSICAL RESOURCES OF INFORMATION PROCESSES AND TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    Mikhail O. Kolbanev

    2014-11-01

    Full Text Available Subject of study. The paper describes basic information technologies for automating of information processes of data storage, distribution and processing in terms of required physical resources. It is shown that the study of these processes with such traditional objectives of modern computer science, as the ability to transfer knowledge, degree of automation, information security, coding, reliability, and others, is not enough. The reasons are: on the one hand, the increase in the volume and intensity of information exchange in the subject of human activity and, on the other hand, drawing near to the limit of information systems efficiency based on semiconductor technologies. Creation of such technologies, which not only provide support for information interaction, but also consume a rational amount of physical resources, has become an actual problem of modern engineering development. Thus, basic information technologies for storage, distribution and processing of information to support the interaction between people are the object of study, and physical temporal, spatial and energy resources required for implementation of these technologies are the subject of study. Approaches. An attempt is made to enlarge the possibilities of traditional cybernetics methodology, which replaces the consideration of material information component by states search for information objects. It is done by taking explicitly into account the amount of physical resources required for changes in the states of information media. Purpose of study. The paper deals with working out of a common approach to the comparison and subsequent selection of basic information technologies for storage, distribution and processing of data, taking into account not only the requirements for the quality of information exchange in particular subject area and the degree of technology application, but also the amounts of consumed physical resources. Main findings. Classification of resources

  16. Two stage bioethanol refining with multi litre stacked microbial fuel cell and microbial electrolysis cell.

    Science.gov (United States)

    Sugnaux, Marc; Happe, Manuel; Cachelin, Christian Pierre; Gloriod, Olivier; Huguenin, Gérald; Blatter, Maxime; Fischer, Fabian

    2016-12-01

    Ethanol, electricity, hydrogen and methane were produced in a two stage bioethanol refinery setup based on a 10L microbial fuel cell (MFC) and a 33L microbial electrolysis cell (MEC). The MFC was a triple stack for ethanol and electricity co-generation. The stack configuration produced more ethanol with faster glucose consumption the higher the stack potential. Under electrolytic conditions ethanol productivity outperformed standard conditions and reached 96.3% of the theoretically best case. At lower external loads currents and working potentials oscillated in a self-synchronized manner over all three MFC units in the stack. In the second refining stage, fermentation waste was converted into methane, using the scale up MEC stack. The bioelectric methanisation reached 91% efficiency at room temperature with an applied voltage of 1.5V using nickel cathodes. The two stage bioethanol refining process employing bioelectrochemical reactors produces more energy vectors than is possible with today's ethanol distilleries.

  17. Physical Processes in the Interstellar Medium

    CERN Document Server

    Klessen, Ralf S

    2014-01-01

    Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). Understanding its physical properties and dynamical behavior is of pivotal importance to many areas of astronomy and astrophysics. Galaxy formation and evolution, the formation of stars, cosmic nucleosynthesis, the origin of large complex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental building blocks of planets, all these processes are intimately coupled to the physics of the interstellar medium. However, despite its importance, its structure and evolution is still not fully understood. Observations reveal that the interstellar medium is highly turbulent, consists of different chemical phases, and is characterized by complex structure on all resolvable spatial and temporal scales. Our current numerical and theoretical models describe it as a strongly coupled system that is far from equilibrium and where th...

  18. Two-Stage Power Factor Corrected Power Supplies: The Low Component-Stress Approach

    DEFF Research Database (Denmark)

    Petersen, Lars; Andersen, Michael Andreas E.

    2002-01-01

    The discussion concerning the use of single-stage contra two-stage PFC solutions has been going on for the last decade and it continues. The purpose of this paper is to direct the focus back on how the power is processed and not so much as to the number of stages or the amount of power processed....... The performance of the basic DC/DC topologies is reviewed with focus on the component stress. The knowledge obtained in this process is used to review some examples of the alternative PFC solutions and compare these solutions with the basic twostage PFC solution....

  19. Characterization of component interactions in two-stage axial turbine

    Directory of Open Access Journals (Sweden)

    Adel Ghenaiet

    2016-08-01

    Full Text Available This study concerns the characterization of both the steady and unsteady flows and the analysis of stator/rotor interactions of a two-stage axial turbine. The predicted aerodynamic performances show noticeable differences when simulating the turbine stages simultaneously or separately. By considering the multi-blade per row and the scaling technique, the Computational fluid dynamics (CFD produced better results concerning the effect of pitchwise positions between vanes and blades. The recorded pressure fluctuations exhibit a high unsteadiness characterized by a space–time periodicity described by a double Fourier decomposition. The Fast Fourier Transform FFT analysis of the static pressure fluctuations recorded at different interfaces reveals the existence of principal harmonics and their multiples, and each lobed structure of pressure wave corresponds to the number of vane/blade count. The potential effect is seen to propagate both upstream and downstream of each blade row and becomes accentuated at low mass flow rates. Between vanes and blades, the potential effect is seen to dominate the quasi totality of blade span, while downstream the blades this effect seems to dominate from hub to mid span. Near the shroud the prevailing effect is rather linked to the blade tip flow structure.

  20. Characterization of component interactions in two-stage axial turbine

    Institute of Scientific and Technical Information of China (English)

    Adel Ghenaiet; Kaddour Touil

    2016-01-01

    This study concerns the characterization of both the steady and unsteady flows and the analysis of stator/rotor interactions of a two-stage axial turbine. The predicted aerodynamic perfor-mances show noticeable differences when simulating the turbine stages simultaneously or sepa-rately. By considering the multi-blade per row and the scaling technique, the Computational fluid dynamics (CFD) produced better results concerning the effect of pitchwise positions between vanes and blades. The recorded pressure fluctuations exhibit a high unsteadiness characterized by a space–time periodicity described by a double Fourier decomposition. The Fast Fourier Transform FFT analysis of the static pressure fluctuations recorded at different interfaces reveals the existence of principal harmonics and their multiples, and each lobed structure of pressure wave corresponds to the number of vane/blade count. The potential effect is seen to propagate both upstream and downstream of each blade row and becomes accentuated at low mass flow rates. Between vanes and blades, the potential effect is seen to dominate the quasi totality of blade span, while down-stream the blades this effect seems to dominate from hub to mid span. Near the shroud the prevail-ing effect is rather linked to the blade tip flow structure.

  1. Gas loading system for LANL two-stage gas guns

    Science.gov (United States)

    Gibson, Lee; Bartram, Brian; Dattelbaum, Dana; Lang, John; Morris, John

    2015-06-01

    A novel gas loading system was designed for the specific application of remotely loading high purity gases into targets for gas-gun driven plate impact experiments. The high purity gases are loaded into well-defined target configurations to obtain Hugoniot states in the gas phase at greater than ambient pressures. The small volume of the gas samples is challenging, as slight changing in the ambient temperature result in measurable pressure changes. Therefore, the ability to load a gas gun target and continually monitor the sample pressure prior to firing provides the most stable and reliable target fielding approach. We present the design and evaluation of a gas loading system built for the LANL 50 mm bore two-stage light gas gun. Targets for the gun are made of 6061 Al or OFHC Cu, and assembled to form a gas containment cell with a volume of approximately 1.38 cc. The compatibility of materials was a major consideration in the design of the system, particularly for its use with corrosive gases. Piping and valves are stainless steel with wetted seals made from Kalrez and Teflon. Preliminary testing was completed to ensure proper flow rate and that the proper safety controls were in place. The system has been used to successfully load Ar, Kr, Xe, and anhydrous ammonia with purities of up to 99.999 percent. The design of the system, and example data from the plate impact experiments will be shown. LA-UR-15-20521

  2. Reducing the risk of foaming and decreasing viscosity by two-stage anaerobic digestion of sugar beet pressed pulp.

    Science.gov (United States)

    Stoyanova, Elitza; Forsthuber, Boris; Pohn, Stefan; Schwarz, Christian; Fuchs, Werner; Bochmann, Günther

    2014-04-01

    Anaerobic digestion (AD) of sugar beet pressed pulp (SBPP) is a promising treatment concept. It produces biogas as a renewable energy source making sugar production more energy efficient and it turns SBPP from a residue into a valuable resource. In this study one- and two-stage mono fermentation at mesophilic conditions in a continuous stirred tank reactor were compared. Also the optimal incubation temperature for the pre-acidification stage was studied. The fastest pre-acidification, with a hydraulic retention time (HRT) of 4 days, occurred at a temperature of 55 °C. In the methanogenic reactor of the two-stage system stable fermentation at loading rate of 7 kg VS/m³ d was demonstrated. No artificial pH adjustment was necessary to maintain optimum levels in both the pre-acidification and the methanogenic reactor. The total HRT of the two-stage AD was 36 days which is considerably lower compared to the one-stage AD (50 days). The frequently observed problem of foaming at high loading rates was less severe in the two-stage reactor. Moreover the viscosity of digestate in the methanogenic stage of the two-stage fermentation was in average tenfold lower than in the one-stage fermentation. This decreases the energy input for the reactor stirring about 80 %. The observed advantages make the two-stage process economically attractive, despite higher investments for a two reactor system.

  3. Effects of earthworm casts and zeolite on the two-stage composting of green waste

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lu, E-mail: zhanglu1211@gmail.com; Sun, Xiangyang, E-mail: xysunbjfu@gmail.com

    2015-05-15

    Highlights: • Earthworm casts (EWCs) and clinoptilolite (CL) were used in green waste composting. • Addition of EWCs + CL improved physico-chemical and microbiological properties. • Addition of EWCs + CL extended the duration of thermophilic periods during composting. • Addition of EWCs + CL enhanced humification, cellulose degradation, and nutrients. • Combined addition of 0.30% EWCs + 25% CL reduced composting time to 21 days. - Abstract: Because it helps protect the environment and encourages economic development, composting has become a viable method for organic waste disposal. The objective of this study was to investigate the effects of earthworm casts (EWCs) (at 0.0%, 0.30%, and 0.60%) and zeolite (clinoptilolite, CL) (at 0%, 15%, and 25%) on the two-stage composting of green waste. The combination of EWCs and CL improved the conditions of the composting process and the quality of the compost products in terms of the thermophilic phase, humification, nitrification, microbial numbers and enzyme activities, the degradation of cellulose and hemicellulose, and physico-chemical characteristics and nutrient contents of final composts. The compost matured in only 21 days with the optimized two-stage composting method rather than in the 90–270 days required for traditional composting. The optimal two-stage composting and the best quality compost were obtained with 0.30% EWCs and 25% CL.

  4. Stochastic processes from physics to finance

    CERN Document Server

    Paul, Wolfgang

    2013-01-01

    This book introduces the theory of stochastic processes with applications taken from physics and finance. Fundamental concepts like the random walk or Brownian motion but also Levy-stable distributions are discussed. Applications are selected to show the interdisciplinary character of the concepts and methods. In the second edition of the book a discussion of extreme events ranging from their mathematical definition to their importance for financial crashes was included. The exposition of basic notions of probability theory and the Brownian motion problem as well as the relation between conservative diffusion processes and quantum mechanics is expanded. The second edition also enlarges the treatment of financial markets. Beyond a presentation of geometric Brownian motion and the Black-Scholes approach to option pricing as well as the econophysics analysis of the stylized facts of financial markets, an introduction to agent based modeling approaches is given.

  5. Noncausal two-stage image filtration at presence of observations with anomalous errors

    Directory of Open Access Journals (Sweden)

    S. V. Vishnevyy

    2013-04-01

    Full Text Available Introduction. It is necessary to develop adaptive algorithms, which allow to detect such regions and to apply filter with respective parameters for suppression of anomalous noises for the purposes of image filtration, which consist of regions with anomalous errors. Development of adaptive algorithm for non-causal two-stage images filtration at pres-ence of observations with anomalous errors. The adaptive algorithm for noncausal two-stage filtration is developed. On the first stage the adaptive one-dimensional algorithm for causal filtration is used for independent processing along rows and columns of image. On the second stage the obtained data are united and a posteriori estimations are calculated. Results of experimental investigations. The developed adaptive algorithm for noncausal images filtration at presence of observations with anomalous errors is investigated on the model sample by means of statistical modeling on PC. The image is modeled as a realization of Gaussian-Markov random field. The modeled image is corrupted with uncorrelated Gaussian noise. Regions of image with anomalous errors are corrupted with uncorrelated Gaussian noise which has higher power than normal noise on the rest part of the image. Conclusions. The analysis of adaptive algorithm for noncausal two-stage filtration is done. The characteristics of accuracy of computed estimations are shown. The comparisons of first stage and second stage of the developed adaptive algorithm are done. Adaptive algorithm is compared with known uniform two-stage algorithm of image filtration. According to the obtained results the uniform algorithm does not suppress anomalous noise meanwhile the adaptive algorithm shows good results.

  6. Residence time and physical processes in lakes

    Directory of Open Access Journals (Sweden)

    Nicoletta SALA

    2003-09-01

    Full Text Available The residence time of a lake is highly dependent on internal physical processes in the water mass conditioning its hydrodynamics; early attempts to evaluate this physical parameter emphasize the complexity of the problem, which depends on very different natural phenomena with widespread synergies. The aim of this study is to analyse the agents involved in these processes and arrive at a more realistic definition of water residence time which takes account of these agents, and how they influence internal hydrodynamics. With particular reference to temperate lakes, the following characteristics are analysed: 1 the set of the lake's caloric components which, along with summer heating, determine the stabilizing effect of the surface layers, and the consequent thermal stratification, as well as the winter destabilizing effect; 2 the wind force, which transfers part of its momentum to the water mass, generating a complex of movements (turbulence, waves, currents with the production of active kinetic energy; 3 the water flowing into the lake from the tributaries, and flowing out through the outflow, from the standpoint of hydrology and of the kinetic effect generated by the introduction of these water masses into the lake. These factors were studied in the context of the general geographical properties of the lake basin and the watershed (latitude, longitude, morphology, also taking account of the local and regional climatic situation. Also analysed is the impact of ongoing climatic change on the renewal of the lake water, which is currently changing the equilibrium between lake and atmosphere, river and lake, and relationships

  7. Two-stage continuous fermentation of Saccharomycopsis fibuligeria and Candida utilis.

    Science.gov (United States)

    Admassu, W; Korus, R A; Heimsch, R C

    1983-11-01

    Biomass production and carbohydrate reduction were determined for a two-stage continuous fermentation process with a simulated potato processing waste feed. The amylolytic yeast Saccharomycopsis fibuligera was grown in the first stage and a mixed culture of S. fibuligera and Candida utilis was maintained in the second stage. All conditions for the first and second stages were fixed except the flow of medium to the second stage was varied. Maximum biomass production occurred at a second stage dilution rate, D(2), of 0.27 h (-1). Carbohydrate reduction was inversely proportional to D(2), between 0.10 and 0.35 h (-1).

  8. PERFORMANCE STUDY OF A TWO STAGE SOLAR ADSORPTION REFRIGERATION SYSTEM

    Directory of Open Access Journals (Sweden)

    BAIJU. V

    2011-07-01

    Full Text Available The present study deals with the performance of a two stage solar adsorption refrigeration system with activated carbon-methanol pair investigated experimentally. Such a system was fabricated and tested under the conditions of National Institute of Technology Calicut, Kerala, India. The system consists of a parabolic solar concentrator,two water tanks, two adsorbent beds, condenser, expansion device, evaporator and accumulator. In this particular system the second water tank is act as a sensible heat storage device so that the system can be used during night time also. The system has been designed for heating 50 litres of water from 25oC to 90oC as well ascooling 10 litres of water from 30oC to 10oC within one hour. The performance parameters such as specific cooling power (SCP, coefficient of performance, solar COP and exergetic efficiency are studied. The dependency between the exergetic efficiency and cycle COP with the driving heat source temperature is also studied. The optimum heat source temperature for this system is determined as 72.4oC. The results show that the system has better performance during night time as compared to the day time. The system has a mean cycle COP of 0.196 during day time and 0.335 for night time. The mean SCP values during day time and night time are 47.83 and 68.2, respectively. The experimental results also demonstrate that the refrigerator has cooling capacity of 47 to 78 W during day time and 57.6 W to 104.4W during night time.

  9. Bringing life to soil physical processes

    Science.gov (United States)

    Hallett, P. D.

    2013-12-01

    When Oklahoma's native prairie grass roots were replaced by corn, the greatest environmental (and social) disaster ever to hit America ensued. The soils lost structure, physical binding by roots was annihilated and when drought came the Great Dust Bowl commenced. This form of environmental disaster has repeated over history and although not always apparent, similar processes drive the degradation of seemingly productive farmland and forests. But just as negative impacts on biology are deleterious to soil physical properties, positive impacts could reverse these trends. In finding solutions to soil sustainability and food security, we should be able to exploit biological processes to improve soil physical properties. This talk will focus on a quantitative understanding of how biology changes soil physical behaviour. Like the Great Dust Bowl, it starts with reinforcement mechanisms by plant roots. We found that binding of soil by cereal (barley) roots within 5 weeks of planting can more than double soil shear strength, with greater plant density causing greater reinforcement. With time, however, the relative impact of root reinforcement diminishes due to root turnover and aging of the seedbed. From mechanical tests of individual roots, reasonable predictions of reinforcement by tree roots are possible with fibre bundle models. With herbaceous plants like cereals, however, the same parameters (root strength, stiffness, size and distribution) result in a poor prediction. We found that root type, root age and abiotic factors such as compaction and waterlogging affect mechanical behaviour, further complicating the understanding and prediction of root reinforcement. For soil physical stability, the interface between root and soil is an extremely important zone in terms of resistance of roots to pull-out and rhizosphere formation. Compounds analogous to root exudates have been found with rheological tests to initially decrease the shear stress where wet soils flow, but

  10. Digital Signal Processing applied to Physical Signals

    CERN Document Server

    Alberto, Diego; Musa, L

    2011-01-01

    It is well known that many of the scientific and technological discoveries of the XXI century will depend on the capability of processing and understanding a huge quantity of data. With the advent of the digital era, a fully digital and automated treatment can be designed and performed. From data mining to data compression, from signal elaboration to noise reduction, a processing is essential to manage and enhance features of interest after every data acquisition (DAQ) session. In the near future, science will go towards interdisciplinary research. In this work there will be given an example of the application of signal processing to different fields of Physics from nuclear particle detectors to biomedical examinations. In Chapter 1 a brief description of the collaborations that allowed this thesis is given, together with a list of the publications co-produced by the author in these three years. The most important notations, definitions and acronyms used in the work are also provided. In Chapter 2, the last r...

  11. Desempenho de processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB para tratamento de águas residuárias de suinocultura Performance of two-stage anaerobic process (baffled reactor (ABR followed by an upflow sludge blanket reactor (UASB treating swine wastewater

    Directory of Open Access Journals (Sweden)

    Gracie F. R. Fernandes

    2006-04-01

    Full Text Available Avaliou-se o efeito das águas residuárias de suinocultura com concentrações de sólidos suspensos totais em torno de 6.000 mg L-1 (DQOtotal variando de 7.557 a 11.640 mg L-1 no desempenho de processo anaeróbio em dois estágios compostos por reator compartimentado (ABR e reator de fluxo ascendente com manta de lodo (UASB, instalados em série, em escala-piloto (volumes de 530 e 120 L, respectivamente, submetidos a tempos de detenção hidráulica (TDH de 56 a 18 h no primeiro reator e de 13 a 4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 71,1 a 87,5% no reator ABR e de 41,5 a 50,1% no reator UASB, resultando em valores médios de 86,8 a 94,9% para o sistema de tratamento anaeróbio em dois estágios com carga orgânica volumétrica (COV, na faixa de 5,05 a 10,12 kg DQOtotal (m³ d-1, no reator ABR, e de 2,83 a 9,63 kg DQOtotal (m³ d-1, no reator UASB. As eficiências de remoção de SST e SSV foram da ordem de 95,6%. O teor de metano no biogás manteve-se acima de 70% para os dois reatores. A produção volumétrica de metano máxima de 0,755 m³ CH4 (m³ d-1 ocorreu no reator 1, com COV de 10,12 kg DQOtotal (m³ d-1 e TDH de 18 h. Os valores médios de pH variaram na faixa de 7,2 a 8,0 para os efluentes dos reatores 1 e 2. Os ácidos voláteis totais mantiveram-se estáveis com concentrações abaixo de 200 mg L-1. Com variações abruptas e acentuadas de concentrações de SST e DQOtotal do afluente, os reatores mantiveram as eficiências de remoção de DQO e sólidos suspensos, em torno de 70%, e a qualidade do biogás, com 80% de CH4.In this work it was evaluated the effect of swine wastewater with total suspended solid (TSS concentration around 6000 mg L-1 (CODtotal from 7557 to 11640 mg L-1 on the performance of two stage anaerobic process constituted of anaerobic baffled reactors (ABR and an upflow sludge blanket reactor (UASB installed in series, in pilot scale testing (volumes of 530 L and

  12. Thermodynamics principles characterizing physical and chemical processes

    CERN Document Server

    Honig, Jurgen M

    1999-01-01

    This book provides a concise overview of thermodynamics, and is written in a manner which makes the difficult subject matter understandable. Thermodynamics is systematic in its presentation and covers many subjects that are generally not dealt with in competing books such as: Carathéodory''s approach to the Second Law, the general theory of phase transitions, the origin of phase diagrams, the treatment of matter subjected to a variety of external fields, and the subject of irreversible thermodynamics.The book provides a first-principles, postulational, self-contained description of physical and chemical processes. Designed both as a textbook and as a monograph, the book stresses the fundamental principles, the logical development of the subject matter, and the applications in a variety of disciplines. This revised edition is based on teaching experience in the classroom, and incorporates many exercises in varying degrees of sophistication. The stress laid on a didactic, logical presentation, and on the relat...

  13. Physical processes in collapse driven supernova

    Energy Technology Data Exchange (ETDEWEB)

    Mayle, R.W.

    1985-11-01

    A model of the supernova explosion is discussed. The method of neutrino transport is discussed, since the explosive mechanism depends on neutrino heating of the material behind the accretion shock. The core region of these exploding stars becomes unstable to convective motions during the supernova evolution. Convective mixing allows more neutrinos to escape from under the neutrinosphere, and thus increases the amount of heating by neutrinos. An approximate method of incorporating convection is described, and some results of including convection in a computer model is presented. Another phenomena is seen in computer simulations of supernova, oscillations in the neutrino luminosity and mass accretion rate onto the protoneutron star. The last topic discussed in this thesis describes the attempt to understand this oscillation by perturbation of the steady state solution to equations approximating the complex physical processes occurring in the late time supernova. 42 refs., 31 figs.

  14. ONE AND TWO STAGE AUTOHYDROLYSIS PRETREATMENTS FOR ENZYME HYDROLYSIS OF COASTAL BERMUDA GRASS TO PRODUCE FERMENTABLE SUGARS

    Directory of Open Access Journals (Sweden)

    Jung Myoung Lee

    2010-05-01

    Full Text Available Coastal Bermuda grass (CBG is an agricultural residue with considerable potential as a feedstock for lignocellulosic-based ethanol. The treatment of biomass with water at high temperature, termed autohydrolysis, can be used to recover sugars in the filtrate and to improve enzyme digestibility of the pretreated solids. The effect of a two- stage autohydrolysis process with respect to total sugar recovery relative to a one stage process was investigated. CBG was subjected to lab scale one-stage (150, 160, and 170 C and two-stage (150/170 C and 160/170 C isothermal autohydrolysis processes followed by enzyme hydrolysis on the residual solids with different loadings (5 to 30 FPU/g. Two-stage autohydrolysis (160/170 C solubilized 94.2% of the hemicellulose based on the original CBG material but only 17.7% of the cellulose and 30.4% of the lignin. Increases in the severity factor (a combination of time and temperature of autohydrolysis pretreatments decreased the recoverable carbohydrates and total solids. Two-stage autohydrolysis enhanced enzyme digestibility of the cellulose in pretreated solids relative to one-stage autohydrolysis, especially at higher values of FPU/g. The overall total theoretical sugar recovery achievable by the two stage process was 57.8% and for the one stage process only 51.6% with 30 FPU/g. This marginal increase would have to be considered relative to increased complexity of operations when deciding whether to implement one or two stage autohydrolysis.

  15. Health care planning and education via gaming-simulation: a two-stage experiment.

    Science.gov (United States)

    Gagnon, J H; Greenblat, C S

    1977-01-01

    A two-stage process of gaming-simulation design was conducted: the first stage of design concerned national planning for hemophilia care; the second stage of design was for gaming-simulation concerning the problems of hemophilia patients and health care providers. The planning design was intended to be adaptable to large-scale planning for a variety of health care problems. The educational game was designed using data developed in designing the planning game. A broad range of policy-makers participated in the planning game.

  16. Influence of capacity- and time-constrained intermediate storage in two-stage food production systems

    DEFF Research Database (Denmark)

    Akkerman, Renzo; van Donk, Dirk Pieter; Gaalman, Gerard

    2007-01-01

    In food processing, two-stage production systems with a batch processor in the first stage and packaging lines in the second stage are common and mostly separated by capacity- and time-constrained intermediate storage. This combination of constraints is common in practice, but the literature hardly...... of systems like this. Contrary to the common sense in operations management, the LPT rule is able to maximize the total production volume per day. Furthermore, we show that adding one tank has considerable effects. Finally, we conclude that the optimal setup frequency for batches in the first stage...

  17. Accuracy of the One-Stage and Two-Stage Impression Techniques: A Comparative Analysis

    OpenAIRE

    Ladan Jamshidy; Hamid Reza Mozaffari; Payam Faraji; Roohollah Sharifi

    2016-01-01

    Introduction. One of the main steps of impression is the selection and preparation of an appropriate tray. Hence, the present study aimed to analyze and compare the accuracy of one- and two-stage impression techniques. Materials and Methods. A resin laboratory-made model, as the first molar, was prepared by standard method for full crowns with processed preparation finish line of 1 mm depth and convergence angle of 3-4°. Impression was made 20 times with one-stage technique and 20 times with ...

  18. An Investigation on the Formation of Carbon Nanotubes by Two-Stage Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    M. S. Shamsudin

    2012-01-01

    Full Text Available High density of carbon nanotubes (CNTs has been synthesized from agricultural hydrocarbon: camphor oil using a one-hour synthesis time and a titanium dioxide sol gel catalyst. The pyrolysis temperature is studied in the range of 700–900°C at increments of 50°C. The synthesis process is done using a custom-made two-stage catalytic chemical vapor deposition apparatus. The CNT characteristics are investigated by field emission scanning electron microscopy and micro-Raman spectroscopy. The experimental results showed that structural properties of CNT are highly dependent on pyrolysis temperature changes.

  19. Right Axillary Sweating After Left Thoracoscopic Sypathectomy in Two-Stage Surgery

    Directory of Open Access Journals (Sweden)

    Berkant Ozpolat

    2013-06-01

    Full Text Available One stage bilateral or two stage unilateral video assisted thoracoscopic sympathectomy could be performed in the treatment of primary focal hyperhidrosis. Here we present a case with compensatory sweating of contralateral side after a two stage operation.

  20. The Two-stage Constrained Equal Awards and Losses Rules for Multi-Issue Allocation Situation

    NARCIS (Netherlands)

    Lorenzo-Freire, S.; Casas-Mendez, B.; Hendrickx, R.L.P.

    2005-01-01

    This paper considers two-stage solutions for multi-issue allocation situations.Characterisations are provided for the two-stage constrained equal awards and constrained equal losses rules, based on the properties of composition and path independence.

  1. Modelling of two-stage anaerobic digestion using the IWA Anaerobic Digestion Model No. 1 (ADM1).

    Science.gov (United States)

    Blumensaat, F; Keller, J

    2005-01-01

    The aim of the study presented was to implement a process model to simulate the dynamic behaviour of a pilot-scale process for anaerobic two-stage digestion of sewage sludge. The model implemented was initiated to support experimental investigations of the anaerobic two-stage digestion process. The model concept implemented in the simulation software package MATLAB/Simulink is a derivative of the IWA Anaerobic Digestion Model No.1 (ADM1) that has been developed by the IWA task group for mathematical modelling of anaerobic processes. In the present study the original model concept has been adapted and applied to replicate a two-stage digestion process. Testing procedures, including balance checks and 'benchmarking' tests were carried out to verify the accuracy of the implementation. These combined measures ensured a faultless model implementation without numerical inconsistencies. Parameters for both, the thermophilic and the mesophilic process stage, have been estimated successfully using data from lab-scale experiments described in literature. Due to the high number of parameters in the structured model, it was necessary to develop a customised procedure that limited the range of parameters to be estimated. The accuracy of the optimised parameter sets has been assessed against experimental data from pilot-scale experiments. Under these conditions, the model predicted reasonably well the dynamic behaviour of a two-stage digestion process in pilot scale.

  2. A Computational Model for Two-stage 4K-Pulse Tube Cooler: Part I.Theoretical Model and Numerical Method

    Institute of Scientific and Technical Information of China (English)

    Y.L. Ju; A.T.A.M. de Waele

    2001-01-01

    A new mixed Eulerian-Lagrangian computational model for simulating and visualizing the internal processes and the variations of dynamic parameters of a two-stage pulse tube cooler (PTC) operating at 4 K-temperature region has been developed. We use the Lagrangian method, a set of moving grids, to follow the exact tracks of gas particles as they move with pressure oscillation in the pulse tube to avoid any numerical false diffusion. The Eulerian approach, a set of fixed computational grids, is used to simulate the variations of dynamic parameters in the regenerator. A variety of physical factors, such as real thermal properties of helium, multi-layered magnetic regenerative materials, pressure drop and heat transfer in the regenerator, and heat exchangers, are taken into account in this model. The present modeling is very effective for visualizing the internal physical processes in 4 K-pulse tube coolers.

  3. Physics as an Enterprise of Process Philosophy

    Science.gov (United States)

    Rangacharyulu, Chary

    2005-01-01

    Physics, as a discipline, attempts to discern the mysteries of physical universe and it is also an inspiration for technological innovations which contribute to the good or demise of human civilization. While it continues to have tremendous impact on the technological front, one wonders if physics, as an enterprise engaged in providing a coherent…

  4. The Stress Process in Physical Education

    Science.gov (United States)

    Blankenship, Bonnie Tjeerdsma

    2007-01-01

    Negative stress in physical education can reduce a student's enjoyment of physical activity and destroy the individual's desire to be a lifelong mover. The purpose of this article is to explore the concept of stress in physical education. Stress is defined as a substantial imbalance between the demand of a situation and the individual's capability…

  5. Two-Stage Exams Improve Student Learning in an Introductory Geology Course: Logistics, Attendance, and Grades

    Science.gov (United States)

    Knierim, Katherine; Turner, Henry; Davis, Ralph K.

    2015-01-01

    Two-stage exams--where students complete part one of an exam closed book and independently and part two is completed open book and independently (two-stage independent, or TS-I) or collaboratively (two-stage collaborative, or TS-C)--provide a means to include collaborative learning in summative assessments. Collaborative learning has been shown to…

  6. An integrated two-stage support vector machine approach to forecast inundation maps during typhoons

    Science.gov (United States)

    Jhong, Bing-Chen; Wang, Jhih-Huang; Lin, Gwo-Fong

    2017-04-01

    During typhoons, accurate forecasts of hourly inundation depths are essential for inundation warning and mitigation. Due to the lack of observed data of inundation maps, sufficient observed data are not available for developing inundation forecasting models. In this paper, the inundation depths, which are simulated and validated by a physically based two-dimensional model (FLO-2D), are used as a database for inundation forecasting. A two-stage inundation forecasting approach based on Support Vector Machine (SVM) is proposed to yield 1- to 6-h lead-time inundation maps during typhoons. In the first stage (point forecasting), the proposed approach not only considers the rainfall intensity and inundation depth as model input but also simultaneously considers cumulative rainfall and forecasted inundation depths. In the second stage (spatial expansion), the geographic information of inundation grids and the inundation forecasts of reference points are used to yield inundation maps. The results clearly indicate that the proposed approach effectively improves the forecasting performance and decreases the negative impact of increasing forecast lead time. Moreover, the proposed approach is capable of providing accurate inundation maps for 1- to 6-h lead times. In conclusion, the proposed two-stage forecasting approach is suitable and useful for improving the inundation forecasting during typhoons, especially for long lead times.

  7. Radiative torque alignment: Essential Physical Processes

    CERN Document Server

    Hoang, Thiem

    2007-01-01

    We study physical processes that affect the alignment of grains subject to radiative torques (RATs). To describe the action of the RATs we use the analytical model (AMO) of RATs introduced in Paper I, namely, in Lazarian & Hoang (2007). We focus our discussion on the RAT alignment by anisotropic radiation flux in respect to magnetic field. Such an alignment does not invoke paramagnetic, i.e. Davis-Greenstein, dissipation, but, nevertheless, grains tend to align with long axes perpendicular to magnetic field. We use phase space trajectory maps to describe the alignment. When we account for thermal fluctuations within grain material, we show that for grains, which are characterized by a triaxial ellipsoid of inertia, the zero-J attractor point obtained in our earlier study develops into a low-J attractor point. Value at the latter point is the order of thermal angular momentum corresponding to the grain temperature. We show that the alignment of grains with long axes parallel to magnetic field (``wrong alig...

  8. Statistical physics of media processes: Mediaphysics

    Science.gov (United States)

    Kuznetsov, Dmitri V.; Mandel, Igor

    2007-04-01

    The processes of mass communications in complicated social or sociobiological systems such as marketing, economics, politics, animal populations, etc. as a subject for the special scientific subbranch-“mediaphysics”-are considered in its relation with sociophysics. A new statistical physics approach to analyze these phenomena is proposed. A keystone of the approach is an analysis of population distribution between two or many alternatives: brands, political affiliations, or opinions. Relative distances between a state of a “person's mind” and the alternatives are measures of propensity to buy (to affiliate, or to have a certain opinion). The distribution of population by those relative distances is time dependent and affected by external (economic, social, marketing, natural) and internal (influential propagation of opinions, “word of mouth”, etc.) factors, considered as fields. Specifically, the interaction and opinion-influence field can be generalized to incorporate important elements of Ising-spin-based sociophysical models and kinetic-equation ones. The distributions were described by a Schrödinger-type equation in terms of Green's functions. The developed approach has been applied to a real mass-media efficiency problem for a large company and generally demonstrated very good results despite low initial correlations of factors and the target variable.

  9. Proton computed tomography from multiple physics processes

    Science.gov (United States)

    Bopp, C.; Colin, J.; Cussol, D.; Finck, Ch; Labalme, M.; Rousseau, M.; Brasse, D.

    2013-10-01

    Proton CT (pCT) nowadays aims at improving hadron therapy treatment planning by mapping the relative stopping power (RSP) of materials with respect to water. The RSP depends mainly on the electron density of the materials. The main information used is the energy of the protons. However, during a pCT acquisition, the spatial and angular deviation of each particle is recorded and the information about its transmission is implicitly available. The potential use of those observables in order to get information about the materials is being investigated. Monte Carlo simulations of protons sent into homogeneous materials were performed, and the influence of the chemical composition on the outputs was studied. A pCT acquisition of a head phantom scan was simulated. Brain lesions with the same electron density but different concentrations of oxygen were used to evaluate the different observables. Tomographic images from the different physics processes were reconstructed using a filtered back-projection algorithm. Preliminary results indicate that information is present in the reconstructed images of transmission and angular deviation that may help differentiate tissues. However, the statistical uncertainty on these observables generates further challenge in order to obtain an optimal reconstruction and extract the most pertinent information.

  10. Development and optimization of a two-stage gasifier for heat and power production

    Science.gov (United States)

    Kosov, V. V.; Zaichenko, V. M.

    2016-11-01

    The major methods of biomass thermal conversion are combustion in excess oxygen, gasification in reduced oxygen, and pyrolysis in the absence of oxygen. The end products of these methods are heat, gas, liquid and solid fuels. From the point of view of energy production, none of these methods can be considered optimal. A two-stage thermal conversion of biomass based on pyrolysis as the first stage and pyrolysis products cracking as the second stage can be considered the optimal method for energy production that allows obtaining synthesis gas consisting of hydrogen and carbon monoxide and not containing liquid or solid particles. On the base of the two stage cracking technology, there was designed an experimental power plant of electric power up to 50 kW. The power plant consists of a thermal conversion module and a gas engine power generator adapted for operation on syngas. Purposes of the work were determination of an optimal operation temperature of the thermal conversion module and an optimal mass ratio of processed biomass and charcoal in cracking chamber of the thermal conversion module. Experiments on the pyrolysis products cracking at various temperatures show that the optimum cracking temperature is equal to 1000 °C. From the results of measuring the volume of gas produced in different mass ratios of charcoal and wood biomass processed, it follows that the maximum volume of the gas in the range of the mass ratio equal to 0.5-0.6.

  11. The influence of partial oxidation mechanisms on tar destruction in TwoStage biomass gasification

    DEFF Research Database (Denmark)

    Ahrenfeldt, Jesper; Egsgaard, Helge; Stelte, Wolfgang

    2013-01-01

    TwoStage gasification of biomass results in almost tar free producer gas suitable for multiple end-use purposes. In the present study, it is investigated to what extent the partial oxidation process of the pyrolysis gas from the first stage is involved in direct and in-direct tar destruction and ...... tar destruction and a high moisture content of the biomass enhances the decomposition of phenol and inhibits the formation of naphthalene. This enhances tar conversion and gasification in the char-bed, and thus contributes in-directly to the tar destruction.......TwoStage gasification of biomass results in almost tar free producer gas suitable for multiple end-use purposes. In the present study, it is investigated to what extent the partial oxidation process of the pyrolysis gas from the first stage is involved in direct and in-direct tar destruction...... and conversion. The study identifies the following major impact factors regarding tar content in the producer gas: oxidation temperature, excess air ratio and biomass moisture content. In a experimental setup, wood pellets were pyrolyzed and the resulting pyrolysis gas was transferred in a heated partial...

  12. Two stage heterotrophy/photoinduction culture of Scenedesmus incrassatulus: potential for lutein production.

    Science.gov (United States)

    Flórez-Miranda, Liliana; Cañizares-Villanueva, Rosa Olivia; Melchy-Antonio, Orlando; Jerónimo, Fernando Martínez-; Flores-Ortíz, Cesar Mateo

    2017-09-16

    A biomass production process including two stages, heterotrophy/photoinduction (TSHP), was developed to improve biomass and lutein production by the green microalgae Scenedesmus incrassatulus. To determine the effects of different nitrogen sources (yeast extract and urea) and temperature in the heterotrophic stage, experiments using shake flask cultures with glucose as the carbon source were carried out. The highest biomass productivity and specific pigment concentrations were reached using urea+vitamins (U+V) at 30°C. The first stage of the TSHP process was done in a 6L bioreactor, and the inductions in a 3L airlift photobioreactor. At the end of the heterotrophic stage, S. incrassatulus achieved the maximal biomass concentration, increasing from 7.22gL(-1) to 17.98gL(-1) with an increase in initial glucose concentration from 10.6gL(-1) to 30.3gL(-1). However, the higher initial glucose concentration resulted in a lower specific growth rate (μ) and lower cell yield (Yx/s), possibly due to substrate inhibition. After 24h of photoinduction, lutein content in S. incrassatulus biomass was 7 times higher than that obtained at the end of heterotrophic cultivation, and the lutein productivity was 1.6 times higher compared with autotrophic culture of this microalga. Hence, the two-stage heterotrophy/photoinduction culture is an effective strategy for high cell density and lutein production in S. incrassatulus. Copyright © 2017. Published by Elsevier B.V.

  13. Aerobic and two-stage anaerobic-aerobic sludge digestion with pure oxygen and air aeration.

    Science.gov (United States)

    Zupancic, Gregor D; Ros, Milenko

    2008-01-01

    The degradability of excess activated sludge from a wastewater treatment plant was studied. The objective was establishing the degree of degradation using either air or pure oxygen at different temperatures. Sludge treated with pure oxygen was degraded at temperatures from 22 degrees C to 50 degrees C while samples treated with air were degraded between 32 degrees C and 65 degrees C. Using air, sludge is efficiently degraded at 37 degrees C and at 50-55 degrees C. With oxygen, sludge was most effectively degraded at 38 degrees C or at 25-30 degrees C. Two-stage anaerobic-aerobic processes were studied. The first anaerobic stage was always operated for 5 days HRT, and the second stage involved aeration with pure oxygen and an HRT between 5 and 10 days. Under these conditions, there is 53.5% VSS removal and 55.4% COD degradation at 15 days HRT - 5 days anaerobic, 10 days aerobic. Sludge digested with pure oxygen at 25 degrees C in a batch reactor converted 48% of sludge total Kjeldahl nitrogen to nitrate. Addition of an aerobic stage with pure oxygen aeration to the anaerobic digestion enhances ammonium nitrogen removal. In a two-stage anaerobic-aerobic sludge digestion process within 8 days HRT of the aerobic stage, the removal of ammonium nitrogen was 85%.

  14. Two-stage estimation for multivariate recurrent event data with a dependent terminal event.

    Science.gov (United States)

    Chen, Chyong-Mei; Chuang, Ya-Wen; Shen, Pao-Sheng

    2015-03-01

    Recurrent event data arise in longitudinal follow-up studies, where each subject may experience the same type of events repeatedly. The work in this article is motivated by the data from a study of repeated peritonitis for patients on peritoneal dialysis. Due to the aspects of medicine and cost, the peritonitis cases were classified into two types: Gram-positive and non-Gram-positive peritonitis. Further, since the death and hemodialysis therapy preclude the occurrence of recurrent events, we face multivariate recurrent event data with a dependent terminal event. We propose a flexible marginal model, which has three characteristics: first, we assume marginal proportional hazard and proportional rates models for terminal event time and recurrent event processes, respectively; second, the inter-recurrences dependence and the correlation between the multivariate recurrent event processes and terminal event time are modeled through three multiplicative frailties corresponding to the specified marginal models; third, the rate model with frailties for recurrent events is specified only on the time before the terminal event. We propose a two-stage estimation procedure for estimating unknown parameters. We also establish the consistency of the two-stage estimator. Simulation studies show that the proposed approach is appropriate for practical use. The methodology is applied to the peritonitis cohort data that motivated this study. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Effekt of a two-stage nursing assesment and intervention - a randomized intervention study

    DEFF Research Database (Denmark)

    Rosted, Elizabeth Emilie; Poulsen, Ingrid; Hendriksen, Carsten

    to the geriatric outpatient clinic, community health centre, primary physician or arrangements with next-of-kin. Findings: Primary endpoints will be presented as unplanned readmission to ED; admission to nursing home; and death. Secondary endpoints will be presented as physical function; depressive symptoms......Background: Geriatric patients recently discharged from hospital are at risk of unplanned readmissions and admission to nursing home. When discharged directly from Emergency Department (ED) the risk increases, as time pressure often requires focus on the presenting problem, although 80...... % of geriatric patients have complex and often unresolved caring needs. The objective was to examine the effect of a two-stage nursing assessment and intervention to address the patients uncompensated problems given just after discharge from ED and one and six months after. Method: We conducted a prospective...

  16. Numerical simulation of municipal solid waste combustion in a novel two-stage reciprocating incinerator.

    Science.gov (United States)

    Huai, X L; Xu, W L; Qu, Z Y; Li, Z G; Zhang, F P; Xiang, G M; Zhu, S Y; Chen, G

    2008-01-01

    A mathematical model was presented in this paper for the combustion of municipal solid waste in a novel two-stage reciprocating grate furnace. Numerical simulations were performed to predict the temperature, the flow and the species distributions in the furnace, with practical operational conditions taken into account. The calculated results agree well with the test data, and the burning behavior of municipal solid waste in the novel two-stage reciprocating incinerator can be demonstrated well. The thickness of waste bed, the initial moisture content, the excessive air coefficient and the secondary air are the major factors that influence the combustion process. If the initial moisture content of waste is high, both the heat value of waste and the temperature inside incinerator are low, and less oxygen is necessary for combustion. The air supply rate and the primary air distribution along the grate should be adjusted according to the initial moisture content of the waste. A reasonable bed thickness and an adequate excessive air coefficient can keep a higher temperature, promote the burnout of combustibles, and consequently reduce the emission of dioxin pollutants. When the total air supply is constant, reducing primary air and introducing secondary air properly can enhance turbulence and mixing, prolong the residence time of flue gas, and promote the complete combustion of combustibles. This study provides an important reference for optimizing the design and operation of municipal solid wastes furnace.

  17. Two-stage electrodialytic concentration of glyceric acid from fermentation broth.

    Science.gov (United States)

    Habe, Hiroshi; Shimada, Yuko; Fukuoka, Tokuma; Kitamoto, Dai; Itagaki, Masayuki; Watanabe, Kunihiko; Yanagishita, Hiroshi; Sakaki, Keiji

    2010-12-01

    The aim of this research was the application of a two-stage electrodialysis (ED) method for glyceric acid (GA) recovery from fermentation broth. First, by desalting ED, glycerate solutions (counterpart is Na+) were concentrated using ion-exchange membranes, and the glycerate recovery and energy consumption became more efficient with increasing the initial glycerate concentration (30 to 130 g/l). Second, by water-splitting ED, the concentrated glycerate was electroconverted to GA using bipolar membranes. Using a culture broth of Acetobacter tropicalis containing 68.6 g/l of D-glycerate, a final D-GA concentration of 116 g/l was obtained following the two-stage ED process. The total energy consumption for the D-glycerate concentration and its electroconversion to D-GA was approximately 0.92 kWh per 1 kg of D-GA. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Two-stage effects of awareness cascade on epidemic spreading in multiplex networks

    Science.gov (United States)

    Guo, Quantong; Jiang, Xin; Lei, Yanjun; Li, Meng; Ma, Yifang; Zheng, Zhiming

    2015-01-01

    Human awareness plays an important role in the spread of infectious diseases and the control of propagation patterns. The dynamic process with human awareness is called awareness cascade, during which individuals exhibit herd-like behavior because they are making decisions based on the actions of other individuals [Borge-Holthoefer et al., J. Complex Networks 1, 3 (2013), 10.1093/comnet/cnt006]. In this paper, to investigate the epidemic spreading with awareness cascade, we propose a local awareness controlled contagion spreading model on multiplex networks. By theoretical analysis using a microscopic Markov chain approach and numerical simulations, we find the emergence of an abrupt transition of epidemic threshold βc with the local awareness ratio α approximating 0.5 , which induces two-stage effects on epidemic threshold and the final epidemic size. These findings indicate that the increase of α can accelerate the outbreak of epidemics. Furthermore, a simple 1D lattice model is investigated to illustrate the two-stage-like sharp transition at αc≈0.5 . The results can give us a better understanding of why some epidemics cannot break out in reality and also provide a potential access to suppressing and controlling the awareness cascading systems.

  19. Waste-gasification efficiency of a two-stage fluidized-bed gasification system.

    Science.gov (United States)

    Liu, Zhen-Shu; Lin, Chiou-Liang; Chang, Tsung-Jen; Weng, Wang-Chang

    2016-02-01

    This study employed a two-stage fluidized-bed gasifier as a gasification reactor and two additives (CaO and activated carbon) as the Stage-II bed material to investigate the effects of the operating temperature (700°C, 800°C, and 900°C) on the syngas composition, total gas yield, and gas-heating value during simulated waste gasification. The results showed that when the operating temperature increased from 700 to 900°C, the molar percentage of H2 in the syngas produced by the two-stage gasification process increased from 19.4 to 29.7mol% and that the total gas yield and gas-heating value also increased. When CaO was used as the additive, the molar percentage of CO2 in the syngas decreased, and the molar percentage of H2 increased. When activated carbon was used, the molar percentage of CH4 in the syngas increased, and the total gas yield and gas-heating value increased. Overall, CaO had better effects on the production of H2, whereas activated carbon clearly enhanced the total gas yield and gas-heating value. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  20. Two-stage high temperature sludge gasification using the waste heat from hot blast furnace slags.

    Science.gov (United States)

    Sun, Yongqi; Zhang, Zuotai; Liu, Lili; Wang, Xidong

    2015-12-01

    Nowadays, disposal of sewage sludge from wastewater treatment plants and recovery of waste heat from steel industry, become two important environmental issues and to integrate these two problems, a two-stage high temperature sludge gasification approach was investigated using the waste heat in hot slags herein. The whole process was divided into two stages, i.e., the low temperature sludge pyrolysis at ⩽ 900°C in argon agent and the high temperature char gasification at ⩾ 900°C in CO2 agent, during which the heat required was supplied by hot slags in different temperature ranges. Both the thermodynamic and kinetic mechanisms were identified and it was indicated that an Avrami-Erofeev model could best interpret the stage of char gasification. Furthermore, a schematic concept of this strategy was portrayed, based on which the potential CO yield and CO2 emission reduction achieved in China could be ∼1.92∗10(9)m(3) and 1.93∗10(6)t, respectively.

  1. Two staged incentive contract focused on efficiency and innovation matching in critical chain project management

    Directory of Open Access Journals (Sweden)

    Min Zhang

    2014-09-01

    Full Text Available Purpose: The purpose of this paper is to define the relative optimal incentive contract to effectively encourage employees to improve work efficiency while actively implementing innovative behavior. Design/methodology/approach: This paper analyzes a two staged incentive contract coordinated with efficiency and innovation in Critical Chain Project Management using learning real options, based on principle-agent theory. The situational experiment is used to analyze the validity of the basic model. Finding: The two staged incentive scheme is more suitable for employees to create and implement learning real options, which will throw themselves into innovation process efficiently in Critical Chain Project Management. We prove that the combination of tolerance for early failure and reward for long-term success is effective in motivating innovation. Research limitations/implications: We do not include the individual characteristics of uncertain perception, which might affect the consistency of external validity. The basic model and the experiment design need to improve. Practical Implications: The project managers should pay closer attention to early innovation behavior and monitoring feedback of competition time in the implementation of Critical Chain Project Management. Originality/value: The central contribution of this paper is the theoretical and experimental analysis of incentive schemes for innovation in Critical Chain Project Management using the principal-agent theory, to encourage the completion of CCPM methods as well as imitative free-riding on the creative ideas of other members in the team.

  2. Efficiency assessment of wind farms: a two-stage approach

    OpenAIRE

    Vaz, Clara B.; Ferreira, Ângela P.

    2015-01-01

    This study proposes an integrated methodology to provide insights regarding the efficiency of wind farms of two major promoters in the Portuguese energy sector. The focus of the wind farms performance assessment is on the operating stage which corresponds to the electrical energy production process. In a first stage, Data Envelopment Analysis is used to measure the efficiency of wind farms in producing electrical energy from the resources available and exogenous variables. This me...

  3. Two-stage acceleration of solar cosmic rays

    Science.gov (United States)

    Tsap, Yu. T.; Isaeva, E. A.

    2012-12-01

    On the basis of data from the Radio Solar Telescope Network (RSTN), as well as the Geostationary Operational Environmental Satellite (GOES) and the WIND spacecraft, for the period from 1989 to 2006 covering 107 flare events, we investigated the relationship between the intensity of solar cosmic rays and parameters of continuum radio bursts (25-15400 MHz), as well as type II radio bursts in the meter and decahectometer wavelength ranges. Proton fluxes with energies E p > 1-100 MeV were calculated with regard to a reduced heliolongitude. The maximum correlation between solar cosmic rays and solar parameters of microwave bursts was 0.80. Its value was no more than 0.40 for the drift rate of type II bursts and 0.70 for the compression rate of coronal shock waves. Based on linear regression equations, we estimated the contribution of coronal shock waves to the acceleration of protons. We found that major acceleration processes occur in the area of burst energy release and complimentary processes occur at the fronts of coronal shock waves. The contribution of the latter to the acceleration process increases significantly with proton energy.

  4. Product prioritization in a two-stage food production system with intermediate storage

    DEFF Research Database (Denmark)

    Akkerman, Renzo; van Donk, Dirk Pieter

    2007-01-01

    In the food-processing industry, usually a limited number of storage tanks for intermediate storage is available, which are used for different products. The market sometimes requires extremely short lead times for some products, leading to prioritization of these products, partly through the dedi......In the food-processing industry, usually a limited number of storage tanks for intermediate storage is available, which are used for different products. The market sometimes requires extremely short lead times for some products, leading to prioritization of these products, partly through...... the dedication of a storage tank. This type of situation has hardly been investigated, although planners struggle with it in practice. This paper aims at investigating the fundamental effect of prioritization and dedicated storage in a two-stage production system, for various product mixes. We show...

  5. Generating the option of a two-stage nuclear renaissance.

    Science.gov (United States)

    Grimes, Robin W; Nuttall, William J

    2010-08-13

    Concerns about climate change, security of supply, and depleting fossil fuel reserves have spurred a revival of interest in nuclear power generation in Europe and North America, while other regions continue or initiate an expansion. We suggest that the first stage of this process will include replacing or extending the life of existing nuclear power plants, with continued incremental improvements in efficiency and reliability. After 2030, a large-scale second period of construction would allow nuclear energy to contribute substantially to the decarbonization of electricity generation. For nuclear energy to be sustainable, new large-scale fuel cycles will be required that may include fuel reprocessing. Here, we explore the opportunities and constraints in both time periods and suggests ways in which measures taken today might, at modest cost, provide more options in the decades to come. Careful long-term planning, along with parallel efforts aimed at containing waste products and avoiding diversion of material into weapons production, can ensure that nuclear power generation remains a carbon-neutral option.

  6. Two stage hydrolysis of corn stover at high solids content for mixing power saving and scale-up applications.

    Science.gov (United States)

    Liu, Ke; Zhang, Jian; Bao, Jie

    2015-11-01

    A two stage hydrolysis of corn stover was designed to solve the difficulties between sufficient mixing at high solids content and high power input encountered in large scale bioreactors. The process starts with the quick liquefaction to convert solid cellulose to liquid slurry with strong mixing in small reactors, then followed the comprehensive hydrolysis to complete saccharification into fermentable sugars in large reactors without agitation apparatus. 60% of the mixing energy consumption was saved by removing the mixing apparatus in large scale vessels. Scale-up ratio was small for the first step hydrolysis reactors because of the reduced reactor volume. For large saccharification reactors in the second step, the scale-up was easy because of no mixing mechanism was involved. This two stage hydrolysis is applicable for either simple hydrolysis or combined fermentation processes. The method provided a practical process option for industrial scale biorefinery processing of lignocellulose biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Two stage thermophilic sludge digestion - solids degradation, heat and energy considerations

    Energy Technology Data Exchange (ETDEWEB)

    Zupancic, Gregor Drago; Ros, Milenko

    2003-07-01

    The conventional process for solids treatment is mesophilic anaerobic sludge digestion (at about 35{sup o}C). In this process about 44% of volatile solids (VSS) are removed at about 40-50 days retention time with the specific biogas production of about 400 L/kg of VSS inserted. At the National Institute of Chemistry Ljubljana, thermophilic sludge digestion at 50 to 60{sup o}C was studied. As the result of research two-stage anaerobic-aerobic process was developed and patented. A case of 3+12 days retention time (anaerobic + aerobic stage) gave specific biogas production equal to mesophilic process (about 400 L/kg of VSS inserted) and VSS removal of 62% in 15 days of total retention time. A case of 3+6 days retention time gave the same biogas production of 400 L/kg and VSS removal of 49% in 9 days of total retention time. The main problem at thermophilic sludge digestion is the heat requirements for sustaining the process. The biogas produced is not sufficient for covering the heat requirements. This problem was resolved with heat regeneration between outflow and inflow sludge. Such regeneration brought the process equal to mesophilic process. With 80 to 95% excess heat of power production from produced biogas all heat requirements were covered. (author)

  8. A characteristics study on the performance of a two-stage light gas gun

    Institute of Scientific and Technical Information of China (English)

    吴应湘; 郑之初; P.Kupschus

    1995-01-01

    In order to obtain an overall and systematic understanding of the performance of a two-stage light gas gun (TLGG), a numerical code to simulate the process occurring in a gun shot is advanced based on the quasi-one-dimensional unsteady equations of motion with the real gas effect, friction and heat transfer taken into account in a characteristic formulation for both driver and propellant gas. Comparisons of projectile velocities and projectile pressures along the barrel with experimental results from JET (Joint European Torus) and with computational data got by the Lagrangian method indicate that this code can provide results with good accuracy over a wide range of gun geometry and loading conditions.

  9. A Two-stage Tuning Method of Servo Parameters for Feed Drives in Machine Tools

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the evaluation of dynamic performance for feed drives in machine tools, this paper presents a two-stage tuning method of servo parameters. In the first stage, the evaluation of dynamic performance, parameter tuning and optimization on a mechatronic integrated system simulation platform of feed drives are performed. As a result, a servo parameter combination is acquired. In the second stage, the servo parameter combination from the first stage is set and tuned further in a real machine tool whose dynamic performance is measured and evaluated using the cross grid encoder developed by Heidenhain GmbH. A case study shows that this method simplifies the test process effectively and results in a good dynamic performance in a real machine tool.

  10. Physical modeling of failure process of the excavation in horizontal strata based on IR thermography

    Institute of Scientific and Technical Information of China (English)

    HE Man-chao; GONG Wei-li; LI De-jian; ZHAI Hui-ming

    2009-01-01

    In order to capture the mechanism of roadway instability in deep mines, a new approach of Physically Finite Elemental Slab Assemblage (PFESA) is proposed in order to construct a large-scale physical model simulating the geologically horizontal strata. We carried out physical modeling on the deformation and failure processes of roadways subjected to a plane loading scheme. Our laboratory tests were based on work which incorporated infrared (IR) detection, IR radiation temperature (IRT) statistics, image feature extraction and 2D Fourier transformation, from resulting thermographies. The IRT characterizes the mechanical responses from the roadway after loading with two stages, i.e., IRT evolving at higher levels corresponded to shallow mining (≤500 m) during which the roadway deformed gradually (referred to as the "steady deformation stage"); IRT evolving in a quasi-cyclical manner with multiple peaks corresponded to deep mining (800-2600 m), in which the failure mode for the roadway are dominated by breakage and collapse (called the "unsteady deformation stage"). The IR images and 2D Fourier spectra illustrate detailed informa-tion in terms of initiation, nucleation and coalescence of the damage to rock masses and the eventual failure of roadways subject to external loading.

  11. Physical Processes in the Interstellar Medium

    OpenAIRE

    2014-01-01

    Interstellar space is filled with a dilute mixture of charged particles, atoms, molecules and dust grains, called the interstellar medium (ISM). Understanding its physical properties and dynamical behavior is of pivotal importance to many areas of astronomy and astrophysics. Galaxy formation and evolution, the formation of stars, cosmic nucleosynthesis, the origin of large complex, prebiotic molecules and the abundance, structure and growth of dust grains which constitute the fundamental buil...

  12. PHYSICAL SIMULATION OF CONTINUOUS ROLL CASTING PROCESS

    Institute of Scientific and Technical Information of China (English)

    L.H. Zhan; J. Zhong; X.Q. Li; M.H. Huang

    2005-01-01

    A series of simulating experimental studies on the rheological behavior and its influential factors of aluminum alloy in continuous roll-casting process have been explored in this paper with a Gleeble-1500 Thermal-Mechanical Simulation Tester and a set of special clamp system. Relevant rheological rules in the process of coupling transient solidification and continuous deformation of roll-casting conditions are obtained. Experimental results indicate that four different characteristic stages exist in the whole rheological process, and relative constitutive models suitable for the given conditions of continuous roll casting process have been established through multivariable linear regression analysis of the experimental data.

  13. Printed circuit board recycling: Physical processing and copper extraction by selective leaching.

    Science.gov (United States)

    Silvas, Flávia P C; Correa, Mónica M Jiménez; Caldas, Marcos P K; de Moraes, Viviane T; Espinosa, Denise C R; Tenório, Jorge A S

    2015-12-01

    Global generation of waste electrical and electronic equipment (WEEE) is about 40 million tons per year. Constant increase in WEEE generation added to international legislations has improved the development of processes for materials recovery and sustainability of electrical and electronic industry. This paper describes a new hydrometallurgical route (leaching process) to recycle printed circuit boards (PCBs) from printers to recover copper. Methodology included PCBs characterization and a combined route of physical and hydrometallurgical processing. Magnetic separation, acid digestion and chemical analysis by ICP-OES were performed. On leaching process were used two stages: the first one in a sulfuric media and the second in an oxidant media. The results showed that the PCBs composition was 74.6 wt.% of non-magnetic material and 25.4 wt.% of magnetic one. The metallic fraction corresponded to 44.0 wt.%, the polymeric to 28.5 wt.% and the ceramic to 27.5 wt.%. The main metal was copper and its initial content was 32.5 wt.%. On sulfuric leaching 90 wt.% of Al, 40 wt.% of Zn and 8.6 wt.% of Sn were extracted, whereas on oxidant leaching tests the extraction percentage of Cu was 100 wt.%, of Zn 60 wt.% and of Al 10 wt.%. At the end of the hydrometallurgical processing was obtained 100% of copper extraction and the recovery factor was 98.46%, which corresponds to a 32 kg of Cu in 100 kg of PCB. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Electrical Storm Simulation to Improve the Learning Physics Process

    Science.gov (United States)

    Martínez Muñoz, Miriam; Jiménez Rodríguez, María Lourdes; Gutiérrez de Mesa, José Antonio

    2013-01-01

    This work is part of a research project whose main objective is to understand the impact that the use of Information and Communication Technology (ICT) has on the teaching and learning process on the subject of Physics. We will show that, with the use of a storm simulator, physics students improve their learning process on one hand they understand…

  15. Process Physics From Quantum Foam to General Relativity

    CERN Document Server

    Cahill, R T

    2002-01-01

    Progress in the new information-theoretic process physics is reported in which the link to the phenomenology of general relativity is made. In process physics the fundamental assumption is that reality is to be modelled as self-organising semantic (or internal or relational) information using a self-referentially limited neural network model. Previous progress in process physics included the demonstration that space and quantum physics are emergent and unified, with time a distinct non-geometric process, that quantum phenomena are caused by fractal topological defects embedded in and forming a growing three-dimensional fractal process-space, which is essentially a quantum foam. Other features of the emergent physics were: quantum field theory with emergent flavour and confined colour, limited causality and the Born quantum measurement metarule, inertia, time-dilation effects, gravity and the equivalence principle, a growing universe with a cosmological constant, black holes and event horizons, and the emergen...

  16. Performance assessment of two-stage anaerobic digestion of kitchen wastes.

    Science.gov (United States)

    Bo, Zhang; Pin-Jing, He

    2014-01-01

    This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

  17. An unit cost adjusting heuristic algorithm for the integrated planning and scheduling of a two-stage supply chain

    Directory of Open Access Journals (Sweden)

    Jianhua Wang

    2014-10-01

    Full Text Available Purpose: The stable relationship of one-supplier-one-customer is replaced by a dynamic relationship of multi-supplier-multi-customer in current market gradually, and efficient scheduling techniques are important tools of the dynamic supply chain relationship establishing process. This paper studies the optimization of the integrated planning and scheduling problem of a two-stage supply chain with multiple manufacturers and multiple retailers to obtain a minimum supply chain operating cost, whose manufacturers have different production capacities, holding and producing cost rates, transportation costs to retailers.Design/methodology/approach: As a complex task allocation and scheduling problem, this paper sets up an INLP model for it and designs a Unit Cost Adjusting (UCA heuristic algorithm that adjust the suppliers’ supplying quantity according to their unit costs step by step to solve the model.Findings: Relying on the contrasting analysis between the UCA and the Lingo solvers for optimizing many numerical experiments, results show that the INLP model and the UCA algorithm can obtain its near optimal solution of the two-stage supply chain’s planning and scheduling problem within very short CPU time.Research limitations/implications: The proposed UCA heuristic can easily help managers to optimizing the two-stage supply chain scheduling problems which doesn’t include the delivery time and batch of orders. For two-stage supply chains are the most common form of actual commercial relationships, so to make some modification and study on the UCA heuristic should be able to optimize the integrated planning and scheduling problems of a supply chain with more reality constraints.Originality/value: This research proposes an innovative UCA heuristic for optimizing the integrated planning and scheduling problem of two-stage supply chains with the constraints of suppliers’ production capacity and the orders’ delivering time, and has a great

  18. Removal of trichloroethylene (TCE) contaminated soil using a two-stage anaerobic-aerobic composting technique.

    Science.gov (United States)

    Ponza, Supat; Parkpian, Preeda; Polprasert, Chongrak; Shrestha, Rajendra P; Jugsujinda, Aroon

    2010-01-01

    The effect of organic carbon addition on remediation of trichloroethylene (TCE) contaminated clay soil was investigated using a two stage anaerobic-aerobic composting system. TCE removal rate and processes involved were determined. Uncontaminated clay soil was treated with composting materials (dried cow manure, rice husk and cane molasses) to represent carbon based treatments (5%, 10% and 20% OC). All treatments were spiked with TCE at 1,000 mg TCE/kg DW and incubated under anaerobic and mesophillic condition (35 degrees C) for 8 weeks followed by continuous aerobic condition for another 6 weeks. TCE dissipation, its metabolites and biogas composition were measured throughout the experimental period. Results show that TCE degradation depended upon the amount of organic carbon (OC) contained within the composting treatments/matrices. The highest TCE removal percentage (97%) and rate (75.06 micro Mole/kg DW/day) were obtained from a treatment of 10% OC composting matrices as compared to 87% and 27.75 micro Mole/kg DW/day for 20% OC, and 83% and 38.08 micro Mole/kg DW/day for soil control treatment. TCE removal rate was first order reaction kinetics. Highest degradation rate constant (k(1) = 0.035 day(- 1)) was also obtained from the 10% OC treatment, followed by 20% OC (k(1) = 0.026 day(- 1)) and 5% OC or soil control treatment (k(1) = 0.023 day(- 1)). The half-life was 20, 27 and 30 days, respectively. The overall results suggest that sequential two stages anaerobic-aerobic composting technique has potential for remediation of TCE in heavy texture soil, providing that easily biodegradable source of organic carbon is present.

  19. Focused ultrasound simultaneous irradiation/MRI imaging, and two-stage general kinetic model.

    Directory of Open Access Journals (Sweden)

    Sheng-Yao Huang

    Full Text Available Many studies have investigated how to use focused ultrasound (FUS to temporarily disrupt the blood-brain barrier (BBB in order to facilitate the delivery of medication into lesion sites in the brain. In this study, through the setup of a real-time system, FUS irradiation and injections of ultrasound contrast agent (UCA and Gadodiamide (Gd, an MRI contrast agent can be conducted simultaneously during MRI scanning. By using this real-time system, we were able to investigate in detail how the general kinetic model (GKM is used to estimate Gd penetration in the FUS irradiated area in a rat's brain resulting from UCA concentration changes after single FUS irradiation. Two-stage GKM was proposed to estimate the Gd penetration in the FUS irradiated area in a rat's brain under experimental conditions with repeated FUS irradiation combined with different UCA concentrations. The results showed that the focal increase in the transfer rate constant of Ktrans caused by BBB disruption was dependent on the doses of UCA. Moreover, the amount of in vivo penetration of Evans blue in the FUS irradiated area in a rat's brain under various FUS irradiation experimental conditions was assessed to show the positive correlation with the transfer rate constants. Compared to the GKM method, the Two-stage GKM is more suitable for estimating the transfer rate constants of the brain treated with repeated FUS irradiations. This study demonstrated that the entire process of BBB disrupted by FUS could be quantitatively monitored by real-time dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI.

  20. Removal of cesium from simulated liquid waste with countercurrent two-stage adsorption followed by microfiltration

    Energy Technology Data Exchange (ETDEWEB)

    Han, Fei; Zhang, Guang-Hui [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China); Gu, Ping, E-mail: guping@tju.edu.cn [School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer The adsorption isotherm of cesium by copper ferrocyanide followed a Freundlich model. Black-Right-Pointing-Pointer Decontamination factor of cesium was higher in lab-scale test than that in jar test. Black-Right-Pointing-Pointer A countercurrent two-stage adsorption-microfiltration process was achieved. Black-Right-Pointing-Pointer Cesium concentration in the effluent could be calculated. Black-Right-Pointing-Pointer It is a new cesium removal process with a higher decontamination factor. - Abstract: Copper ferrocyanide (CuFC) was used as an adsorbent to remove cesium. Jar test results showed that the adsorption capacity of CuFC was better than that of potassium zinc hexacyanoferrate. Lab-scale tests were performed by an adsorption-microfiltration process, and the mean decontamination factor (DF) was 463 when the initial cesium concentration was 101.3 {mu}g/L, the dosage of CuFC was 40 mg/L and the adsorption time was 20 min. The cesium concentration in the effluent continuously decreased with the operation time, which indicated that the used adsorbent retained its adsorption capacity. To use this capacity, experiments on a countercurrent two-stage adsorption (CTA)-microfiltration (MF) process were carried out with CuFC adsorption combined with membrane separation. A calculation method for determining the cesium concentration in the effluent was given, and batch tests in a pressure cup were performed to verify the calculated method. The results showed that the experimental values fitted well with the calculated values in the CTA-MF process. The mean DF was 1123 when the dilution factor was 0.4, the initial cesium concentration was 98.75 {mu}g/L and the dosage of CuFC and adsorption time were the same as those used in the lab-scale test. The DF obtained by CTA-MF process was more than three times higher than the single-stage adsorption in the jar test.

  1. Markov processes an introduction for physical scientists

    CERN Document Server

    Gillespie, Daniel T

    1991-01-01

    Markov process theory is basically an extension of ordinary calculus to accommodate functions whos time evolutions are not entirely deterministic. It is a subject that is becoming increasingly important for many fields of science. This book develops the single-variable theory of both continuous and jump Markov processes in a way that should appeal especially to physicists and chemists at the senior and graduate level.Key Features* A self-contained, prgamatic exposition of the needed elements of random variable theory* Logically integrated derviations of the Chapman-Kolmogorov e

  2. Two-stage categorization in brand extension evaluation: electrophysiological time course evidence.

    Directory of Open Access Journals (Sweden)

    Qingguo Ma

    Full Text Available A brand name can be considered a mental category. Similarity-based categorization theory has been used to explain how consumers judge a new product as a member of a known brand, a process called brand extension evaluation. This study was an event-related potential study conducted in two experiments. The study found a two-stage categorization process reflected by the P2 and N400 components in brand extension evaluation. In experiment 1, a prime-probe paradigm was presented in a pair consisting of a brand name and a product name in three conditions, i.e., in-category extension, similar-category extension, and out-of-category extension. Although the task was unrelated to brand extension evaluation, P2 distinguished out-of-category extensions from similar-category and in-category ones, and N400 distinguished similar-category extensions from in-category ones. In experiment 2, a prime-probe paradigm with a related task was used, in which product names included subcategory and major-category product names. The N400 elicited by subcategory products was more significantly negative than that elicited by major-category products, with no salient difference in P2. We speculated that P2 could reflect the early low-level and similarity-based processing in the first stage, whereas N400 could reflect the late analytic and category-based processing in the second stage.

  3. Human sperm rheotaxis: a passive physical process

    OpenAIRE

    Zhuoran Zhang; Jun Liu; Jim Meriano; Changhai Ru; Shaorong Xie; Jun Luo; Yu Sun

    2016-01-01

    A long-standing question in natural reproduction is how mammalian sperm navigate inside female reproductive tract and finally reach the egg cell, or oocyte. Recently, fluid flow was proposed as a long–range guidance cue for sperm navigation. Coitus induces fluid flow from oviduct to uterus, and sperm align themselves against the flow direction and swim upstream, a phenomenon termed rheotaxis. Whether sperm rheotaxis is a passive process dominated by fluid mechanics, or sperm actively sense an...

  4. On the design of a low-voltage two-stage OTA using bulk-driven and positive feedback techniques

    Science.gov (United States)

    Khameh, Hassan; Shamsi, Hossein

    2012-09-01

    This article presents the design and simulation of a fully differential two-stage operational transconductance amplifier (OTA) in a 0.18 µm CMOS process with a 0.9 V supply voltage. For this purpose, both the bulk-driven and positive feedback techniques are employed. These techniques increase the DC gain by about 18.5 dB without consuming more power and changing the unity-gain bandwidth and phase margin of the OTA.

  5. Physics of Laser Materials Processing Theory and Experiment

    CERN Document Server

    Gladush, Gennady G

    2011-01-01

    This book describes the basic mechanisms, theory, simulations and technological aspects of Laser processing techniques. It covers the principles of laser quenching, welding, cutting, alloying, selective sintering, ablation, etc. The main attention is paid to the quantitative description. The diversity and complexity of technological and physical processes is discussed using a unitary approach. The book aims on understanding the cause-and-effect relations in physical processes in Laser technologies. It will help researchers and engineers to improve the existing and develop new Laser machining techniques. The book addresses readers with a certain background in general physics and mathematical analysis: graduate students, researchers and engineers practicing laser applications.

  6. Contribution of underlying processes to improved visuospatial working memory associated with physical activity

    Directory of Open Access Journals (Sweden)

    Qingchun Ji

    2017-06-01

    Full Text Available Background Working memory is critical for various cognitive processes and can be separated into two stages: short-term memory storage and manipulation processing. Although previous studies have demonstrated that increased physical activity (PA improves working memory and that males outperform females on visuospatial working memory tasks, few studies have determined the contribution of the two underlying stages to the visuospatial working memory improvement associated with PA. Thus, the aims of the present study were to verify the relationship between physical activity and visuospatial working memory, determine whether one or both stages were affected by PA, and investigate any sex differences. Methods A total of 56 undergraduate students were recruited for this study. Their scores on the International Physical Activity Questionnaire (IPAQ were used to separate them into either a lower PA (n = 26; IPAQ score ≤3,000 metabolic equivalent [MET]-min/week or higher PA (n = 30; IPAQ score >3,000 MET-min/week group. Participants were required to complete three tasks: a visuospatial working memory task, a task that examines the short-term memory storage stage, and a mental rotation task that examines the active manipulation stage. Results Participants in the higher PA group maintained similar accuracy but displayed significantly faster reaction times (RT than those in the lower PA group on the visuospatial working memory and manipulation tasks. By contrast, no difference was observed between groups on the short-term memory storage task. In addition, no effects of sex were detected. Discussion Our results confirm that PA was positively to visuospatial working memory and that this positive relationship was associated with more rapid cognitive processing during the manipulation stage, with little or no relationship between PA and the memory storage stage of visuospatial working memory.

  7. Electric and hybrid electric vehicles: A technology assessment based on a two-stage Delphi study

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, A.D.; Ng, H.K.; Santini, D.J.; Anderson, J.L.

    1997-12-01

    To address the uncertainty regarding future costs and operating attributes of electric and hybrid electric vehicles, a two stage, worldwide Delphi study was conducted. Expert opinions on vehicle attributes, current state of the technology, possible advancements, costs, and market penetration potential were sought for the years 2000, 2010, and 2020. Opinions related to such critical components as batteries, electric drive systems, and hybrid vehicle engines, as well as their respective technical and economic viabilities, were also obtained. This report contains descriptions of the survey methodology, analytical approach, and results of the analysis of survey data, together with a summary of other factors that will influence the degree of market success of electric and hybrid electric vehicle technologies. Responses by industry participants, the largest fraction among all the participating groups, are compared with the overall responses. An evaluation of changes between the two Delphi stages is also summarized. An analysis of battery replacement costs for various types is summarized, and variable operating costs for electric and hybrid vehicles are compared with those of conventional vehicles. A market penetration analysis is summarized, in which projected market shares from the survey are compared with predictions of shares on the basis of two market share projection models that use the cost and physical attributes provided by the survey. Finally, projections of market shares beyond the year 2020 are developed by use of constrained logit models of market shares, statistically fitted to the survey data.

  8. Two-Photon Physics in Hadronic Processes

    Energy Technology Data Exchange (ETDEWEB)

    Carl Carlson; Marc Vanderhaeghen

    2007-11-01

    Two-photon exchange contributions to elastic electron-scattering are reviewed. The apparent discrepancy in the extraction of elastic nucleon form factors between unpolarized Rosenbluth and polarization transfer experiments is discussed, as well as the understanding of this puzzle in terms of two-photon exchange corrections. Calculations of such corrections both within partonic and hadronic frameworks are reviewed. In view of recent spin-dependent electron scattering data, the relation of the two-photon exchange process to the hyperfine splitting in hydrogen is critically examined. The imaginary part of the two-photon exchange amplitude as can be accessed from the beam normal spin asymmetry in elastic electron-nucleon scattering is reviewed. Further extensions and open issues in this field are outlined.

  9. Two-Stage Chaos Optimization Search Application in Maximum Power Point Tracking of PV Array

    Directory of Open Access Journals (Sweden)

    Lihua Wang

    2014-01-01

    Full Text Available In order to deliver the maximum available power to the load under the condition of varying solar irradiation and environment temperature, maximum power point tracking (MPPT technologies have been used widely in PV systems. Among all the MPPT schemes, the chaos method is one of the hot topics in recent years. In this paper, a novel two-stage chaos optimization method is presented which can make search faster and more effective. In the process of proposed chaos search, the improved logistic mapping with the better ergodic is used as the first carrier process. After finding the current optimal solution in a certain guarantee, the power function carrier as the secondary carrier process is used to reduce the search space of optimized variables and eventually find the maximum power point. Comparing with the traditional chaos search method, the proposed method can track the change quickly and accurately and also has better optimization results. The proposed method provides a new efficient way to track the maximum power point of PV array.

  10. A Two-Stage Queue Model to Optimize Layout of Urban Drainage System considering Extreme Rainstorms

    Directory of Open Access Journals (Sweden)

    Xinhua He

    2017-01-01

    Full Text Available Extreme rainstorm is a main factor to cause urban floods when urban drainage system cannot discharge stormwater successfully. This paper investigates distribution feature of rainstorms and draining process of urban drainage systems and uses a two-stage single-counter queue method M/M/1→M/D/1 to model urban drainage system. The model emphasizes randomness of extreme rainstorms, fuzziness of draining process, and construction and operation cost of drainage system. Its two objectives are total cost of construction and operation and overall sojourn time of stormwater. An improved genetic algorithm is redesigned to solve this complex nondeterministic problem, which incorporates with stochastic and fuzzy characteristics in whole drainage process. A numerical example in Shanghai illustrates how to implement the model, and comparisons with alternative algorithms show its performance in computational flexibility and efficiency. Discussions on sensitivity of four main parameters, that is, quantity of pump stations, drainage pipe diameter, rainstorm precipitation intensity, and confidence levels, are also presented to provide guidance for designing urban drainage system.

  11. Autothermal two-stage gasification of low-density waste-derived fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hamel, Stefan [Universitaet Siegen, Institut fuer Energietechnik, Paul-Bonatz-Str. 9-11, D-57068 Siegen (Germany); Hasselbach, Holger [Universitaet Siegen, Institut fuer Energietechnik, Paul-Bonatz-Str. 9-11, D-57068 Siegen (Germany); Weil, Steffen [Universitaet Siegen, Institut fuer Energietechnik, Paul-Bonatz-Str. 9-11, D-57068 Siegen (Germany); Krumm, Wolfgang [Universitaet Siegen, Institut fuer Energietechnik, Paul-Bonatz-Str. 9-11, D-57068 Siegen (Germany)]. E-mail: w.krumm@et.mb.uni-siegen.de

    2007-02-15

    In order to increase the efficiency of waste utilization in thermal conversion processes, pre-treatment is advantageous. With the Herhof Stabilat[reg] process, residual domestic waste is upgraded to waste-derived fuel by means of biological drying and mechanical separation of inerts and metals. The dried and homogenized waste-derived Stabilat[reg] fuel has a relatively high calorific value and contains high volatile matter which makes it suitable for gasification. As a result of extensive mechanical treatment, the Stabilat[reg] produced is of a fluffy appearance with a low density. A two-stage gasifier, based on a parallel-arranged bubbling fluidized bed and a fixed bed reactor, has been developed to convert Stabilat[reg] into hydrogen-rich product gas. This paper focuses on the design and construction of the configured laboratory-scale gasifier and experience with its operation. The processing of low-density fluffy waste-derived fuel using small-scale equipment demands special technical solutions for the core components as well as for the peripheral equipment. These are discussed here. The operating results of Stabilat[reg] gasification are also presented.

  12. Experimental and numerical studies on two-stage combustion of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Houshfar, Eshan

    2012-07-01

    In this thesis, two-stage combustion of biomass was experimentally/numerically investigated in a multifuel reactor. The following emissions issues have been the main focus of the work: 1- NOx and N2O 2- Unburnt species (CO and CxHy) 3- Corrosion related emissions.The study had a focus on two-stage combustion in order to reduce pollutant emissions (primarily NOx emissions). It is well known that pollutant emissions are very dependent on the process conditions such as temperature, reactant concentrations and residence times. On the other hand, emissions are also dependent on the fuel properties (moisture content, volatiles, alkali content, etc.). A detailed study of the important parameters with suitable biomass fuels in order to optimize the various process conditions was performed. Different experimental studies were carried out on biomass fuels in order to study the effect of fuel properties and combustion parameters on pollutant emissions. Process conditions typical for biomass combustion processes were studied. Advanced experimental equipment was used in these studies. The experiments showed the effects of staged air combustion, compared to non-staged combustion, on the emission levels clearly. A NOx reduction of up to 85% was reached with staged air combustion using demolition wood as fuel. An optimum primary excess air ratio of 0.8-0.95 was found as a minimizing parameter for the NOx emissions for staged air combustion. Air staging had, however, a negative effect on N2O emissions. Even though the trends showed a very small reduction in the NOx level as temperature increased for non-staged combustion, the effect of temperature was not significant for NOx and CxHy, neither in staged air combustion or non-staged combustion, while it had a great influence on the N2O and CO emissions, with decreasing levels with increasing temperature. Furthermore, flue gas recirculation (FGR) was used in combination with staged combustion to obtain an enhanced NOx reduction. The

  13. DEVELOPMENT OF COLD CLIMATE HEAT PUMP USING TWO-STAGE COMPRESSION

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Rice, C Keith [ORNL; Abdelaziz, Omar [ORNL; Shrestha, Som S [ORNL

    2015-01-01

    This paper uses a well-regarded, hardware based heat pump system model to investigate a two-stage economizing cycle for cold climate heat pump applications. The two-stage compression cycle has two variable-speed compressors. The high stage compressor was modelled using a compressor map, and the low stage compressor was experimentally studied using calorimeter testing. A single-stage heat pump system was modelled as the baseline. The system performance predictions are compared between the two-stage and single-stage systems. Special considerations for designing a cold climate heat pump are addressed at both the system and component levels.

  14. DEVELOPMENT OF COLD CLIMATE HEAT PUMP USING TWO-STAGE COMPRESSION

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Rice, C Keith [ORNL; Abdelaziz, Omar [ORNL; Shrestha, Som S [ORNL

    2015-01-01

    This paper uses a well-regarded, hardware based heat pump system model to investigate a two-stage economizing cycle for cold climate heat pump applications. The two-stage compression cycle has two variable-speed compressors. The high stage compressor was modelled using a compressor map, and the low stage compressor was experimentally studied using calorimeter testing. A single-stage heat pump system was modelled as the baseline. The system performance predictions are compared between the two-stage and single-stage systems. Special considerations for designing a cold climate heat pump are addressed at both the system and component levels.

  15. [Study on supply and demand relation based on two stages division of market of Chinese materia medica].

    Science.gov (United States)

    Yang, Guang; Guo, Lan-Ping; Wang, Nuo; Zeng, Yan; Huang, Lu-Qi

    2014-01-01

    The complex production processes and long industrial chain in traditional Chinese medicine (TCM) market result in difficulty in Chinese market microstructure research. Based on the defining the logical relationships among different concepts. This paper divides TCM market into two stages as Chinese materia medica resource market and traditional Chinese Patent Medicines market. Under this foundation, we investigated the supply capacity, approaching rules and motivation system of suppliers in TCM market, analyzed the demand situation in the perspective of demand side, and evaluated the purchasing power in terms of population profile, income, and insurance. Furthermore we also analyzed the price formation mechanism in two stages of TCM market. We hope this study can make a positive and promotion effect on TCM market related research.

  16. 后喷技术与两级增压系统的优化匹配对燃烧过程的影响%Effect of Optimization Matching Between Post Injection Technology and Two-Stage Turbocharging System on Combustion Process

    Institute of Scientific and Technical Information of China (English)

    韩志强; 战强; 吴松林; 周小波; 苏万华

    2013-01-01

    根据“高密度-低温燃烧”方案匹配的两级增压系统,使重型柴油机在中低速能实现低排放和高有效热效率。然而,在高速中高负荷工况,增压系统不经过必要的调压手段,会存在排气背压过高的问题,从而使柴油机油耗和烟度均较高,有效热效率较低。为此,本文采用后喷技术和涡端放气技术,通过分析后喷定时、主后喷油量比例和进气压力等参数对排放和有效热效率的影响,得到油路参数与气路参数的协同优化控制方法。研究表明,在高涡前压力工况,相比单次喷射模式,采用“主喷+后喷”的喷油模式,能实现更低排放,但有效热效率会下降。进一步研究发现,随着后喷定时和主后喷油量比例的变化,存在一个适当的后喷定时和后喷油量区间,使缸内碳烟易于降低。同时,随着涡端旁通阀开度增加,NOx排放会不断减小,碳烟排放会出现一个拐点,呈现先减小后增加的趋势,而有效热效率则逐渐增加。这充分说明,在高涡前压力工况,适时放气,能同时改善排放和有效热效率。%Low emissions and high brake thermal efficiency could be achieved in medium and low speed condition by the heavy-duty diesel engine with two-stage turbocharging system based on the high-density low temperature combus-tion theory. However,if the turbocharging system had none pressure regulation means,the exhaust backpressure would be so high that the fuel consumption and smoke intensity of the diesel engine would be relatively high and the brake thermal efficiency would be relatively low in high speed,medium and high load conditions. So post injection and turbo-side deflating technology was used in this paper,and the control method of collaborative optimization of oil and gas parameters could be achieved by analyzing the parameters of post injection timing,fuel quantity propor-tion of main and post injection

  17. Physical processing efficiency of saline vs. alkaline spent batteries

    OpenAIRE

    Cabral,Marta; Nogueira, C. A.; Margarido, F.

    2008-01-01

    Physical processing of spent batteries which includes shredding and sieving operation is the first step for chemical treatment by hydrometallurgy. A laboratory study was carried out to evaluate physical processing efficiency, by analysing the resulting particle size, of alkaline and saline mignon-type Zn-MnO2 batteries. After shredding with a tip shredder, results obtained showed that alkaline batteries were more efficiently size reduced than saline batteries. Difference in particle size dist...

  18. Distributed System of Processing of Data of Physical Experiments

    Science.gov (United States)

    Nazarov, A. A.; Moiseev, A. N.

    2014-11-01

    Complication of physical experiments and increasing volumes of experimental data necessitate the application of supercomputer and distributed computing systems for data processing. Design and development of such systems, their mathematical modeling, and investigation of their characteristics and functional capabilities is an urgent scientific and practical problem. In the present work, the characteristics of operation of such distributed system of processing of data of physical experiments are investigated using the apparatus of theory of queuing networks.

  19. Two-stage light-gas magnetoplasma accelerator for hypervelocity impact simulation

    Science.gov (United States)

    Khramtsov, P. P.; Vasetskij, V. A.; Makhnach, A. I.; Grishenko, V. M.; Chernik, M. Yu; Shikh, I. A.; Doroshko, M. V.

    2016-11-01

    The development of macroparticles acceleration methods for high-speed impact simulation in a laboratory is an actual problem due to increasing of space flights duration and necessity of providing adequate spacecraft protection against micrometeoroid and space debris impacts. This paper presents results of experimental study of a two-stage light- gas magnetoplasma launcher for acceleration of a macroparticle, in which a coaxial plasma accelerator creates a shock wave in a high-pressure channel filled with light gas. Graphite and steel spheres with diameter of 2.5-4 mm were used as a projectile and were accelerated to the speed of 0.8-4.8 km/s. A launching of particle occurred in vacuum. For projectile velocity control the speed measuring method was developed. The error of this metod does not exceed 5%. The process of projectile flight from the barrel and the process of a particle collision with a target were registered by use of high-speed camera. The results of projectile collision with elements of meteoroid shielding are presented. In order to increase the projectile velocity, the high-pressure channel should be filled with hydrogen. However, we used helium in our experiments for safety reasons. Therefore, we can expect that the range of mass and velocity of the accelerated particles can be extended by use of hydrogen as an accelerating gas.

  20. Comparison of microalgae cultivation in photobioreactor, open raceway pond, and a two-stage hybrid system

    Directory of Open Access Journals (Sweden)

    Rakesh R Narala

    2016-08-01

    Full Text Available In the wake of intensive fossil fuel usage and CO2 accumulation in the environment, research is targeted towards sustainable alternate bioenergy that can suffice the growing need for fuel and also that leaves a minimal carbon footprint. Oil production from microalgae can potentially be carried out more efficiently, leaving a smaller footprint and without competing for arable land or biodiverse landscapes. However, current algae cultivation systems and lipid induction processes must be significantly improved and are threatened by contamination with other algae or algal grazers. To address this issue, we have developed an efficient two-stage cultivation system using the marine microalga Tetraselmis sp. M8. This hybrid system combines exponential biomass production in positive pressure air lift-driven bioreactors with a separate synchronized high-lipid induction phase in nutrient deplete open raceway ponds. A comparison to either bioreactor or open raceway pond cultivation system suggests that this process potentially leads to significantly higher productivity of algal lipids. Nutrients are only added to the closed bioreactors while open raceway ponds have turnovers of only a few days, thus reducing the issue of microalgal grazers.

  1. Evidence that viral RNAs have evolved for efficient, two-stage packaging.

    Science.gov (United States)

    Borodavka, Alexander; Tuma, Roman; Stockley, Peter G

    2012-09-25

    Genome packaging is an essential step in virus replication and a potential drug target. Single-stranded RNA viruses have been thought to encapsidate their genomes by gradual co-assembly with capsid subunits. In contrast, using a single molecule fluorescence assay to monitor RNA conformation and virus assembly in real time, with two viruses from differing structural families, we have discovered that packaging is a two-stage process. Initially, the genomic RNAs undergo rapid and dramatic (approximately 20-30%) collapse of their solution conformations upon addition of cognate coat proteins. The collapse occurs with a substoichiometric ratio of coat protein subunits and is followed by a gradual increase in particle size, consistent with the recruitment of additional subunits to complete a growing capsid. Equivalently sized nonviral RNAs, including high copy potential in vivo competitor mRNAs, do not collapse. They do support particle assembly, however, but yield many aberrant structures in contrast to viral RNAs that make only capsids of the correct size. The collapse is specific to viral RNA fragments, implying that it depends on a series of specific RNA-protein interactions. For bacteriophage MS2, we have shown that collapse is driven by subsequent protein-protein interactions, consistent with the RNA-protein contacts occurring in defined spatial locations. Conformational collapse appears to be a distinct feature of viral RNA that has evolved to facilitate assembly. Aspects of this process mimic those seen in ribosome assembly.

  2. The Effect of Effluent Recirculation in a Semi-Continuous Two-Stage Anaerobic Digestion System

    Directory of Open Access Journals (Sweden)

    Karthik Rajendran

    2013-06-01

    Full Text Available The effect of recirculation in increasing organic loading rate (OLR and decreasing hydraulic retention time (HRT in a semi-continuous two-stage anaerobic digestion system using stirred tank reactor (CSTR and an upflow anaerobic sludge bed (UASB was evaluated. Two-parallel processes were in operation for 100 days, one with recirculation (closed system and the other without recirculation (open system. For this purpose, two structurally different carbohydrate-based substrates were used; starch and cotton. The digestion of starch and cotton in the closed system resulted in production of 91% and 80% of the theoretical methane yield during the first 60 days. In contrast, in the open system the methane yield was decreased to 82% and 56% of the theoretical value, for starch and cotton, respectively. The OLR could successfully be increased to 4 gVS/L/day for cotton and 10 gVS/L/day for starch. It is concluded that the recirculation supports the microorganisms for effective hydrolysis of polyhydrocarbons in CSTR and to preserve the nutrients in the system at higher OLRs, thereby improving the overall performance and stability of the process.

  3. AREA DETERMINATION OF DIABETIC FOOT ULCER IMAGES USING A CASCADED TWO-STAGE SVM BASED CLASSIFICATION.

    Science.gov (United States)

    Wang, Lei; Pedersen, Peder; Agu, Emmanuel; Strong, Diane; Tulu, Bengisu

    2016-11-23

    It is standard practice for clinicians and nurses to primarily assess patients' wounds via visual examination. This subjective method can be inaccurate in wound assessment and also represents a significant clinical workload. Hence, computer-based systems, especially implemented on mobile devices, can provide automatic, quantitative wound assessment and can thus be valuable for accurately monitoring wound healing status. Out of all wound assessment parameters, the measurement of the wound area is the most suitable for automated analysis. Most of the current wound boundary determination methods only process the image of the wound area along with a small amount of surrounding healthy skin. In this paper, we present a novel approach that uses Support Vector Machine (SVM) to determine the wound boundary on a foot ulcer image captured with an image capture box, which provides controlled lighting, angle and range conditions. The Simple Linear Iterative Clustering (SLIC) method is applied for effective super-pixel segmentation. A cascaded two-stage classifier is trained as follows: in the first stage a set of k binary SVM classifiers are trained and applied to different subsets of the entire training images dataset, and a set of incorrectly classified instances are collected. In the second stage, another binary SVM classifier is trained on the incorrectly classified set. We extracted various color and texture descriptors from super-pixels that are used as input for each stage in the classifier training. Specifically, we apply the color and Bag-of-Word (BoW) representation of local Dense SIFT features (DSIFT) as the descriptor for ruling out irrelevant regions (first stage), and apply color and wavelet based features as descriptors for distinguishing healthy tissue from wound regions (second stage). Finally, the detected wound boundary is refined by applying a Conditional Random Field (CRF) image processing technique. We have implemented the wound classification on a Nexus

  4. Numerical simulation of a step-piston type series two-stage pulse tube refrigerator

    Science.gov (United States)

    Zhu, Shaowei; Nogawa, Masafumi; Inoue, Tatsuo

    2007-09-01

    A two-stage pulse tube refrigerator has a great advantage in that there are no moving parts at low temperatures. The problem is low theoretical efficiency. In an ordinary two-stage pulse tube refrigerator, the expansion work of the first stage pulse tube is rather large, but is changed to heat. The theoretical efficiency is lower than that of a Stirling refrigerator. A series two-stage pulse tube refrigerator was introduced for solving this problem. The hot end of the regenerator of the second stage is connected to the hot end of the first stage pulse tube. The expansion work in the first stage pulse tube is part of the input work of the second stage, therefore the efficiency is increased. In a simulation result for a step-piston type two-stage series pulse tube refrigerator, the efficiency is increased by 13.8%.

  5. Theory and calculation of two-stage voltage stabilizer on zener diodes

    Directory of Open Access Journals (Sweden)

    G. S. Veksler

    1966-12-01

    Full Text Available Two-stage stabilizer is compared with one-stage. There have been got formulas, which give the possibility to make an engineering calculation. There is an example of the calculation.

  6. Two-stage fungal pre-treatment for improved biogas production from sisal leaf decortication residues

    National Research Council Canada - National Science Library

    Muthangya, Mutemi; Mshandete, Anthony Manoni; Kivaisi, Amelia Kajumulo

    2009-01-01

    .... Pre-treatment of the residue prior to its anaerobic digestion (AD) was investigated using a two-stage pre-treatment approach with two fungal strains, CCHT-1 and Trichoderma reesei in succession in anaerobic batch bioreactors...

  7. TWO-STAGE CHARACTER CLASSIFICATION : A COMBINED APPROACH OF CLUSTERING AND SUPPORT VECTOR CLASSIFIERS

    NARCIS (Netherlands)

    Vuurpijl, L.; Schomaker, L.

    2000-01-01

    This paper describes a two-stage classification method for (1) classification of isolated characters and (2) verification of the classification result. Character prototypes are generated using hierarchical clustering. For those prototypes known to sometimes produce wrong classification results, a

  8. Physical Processes in the MAGO/MFT Systems

    Energy Technology Data Exchange (ETDEWEB)

    Garanin, Sergey F [RFNC-VNIIEF; Reinovsky, Robert E. [Los Alamos National Laboratory

    2015-03-23

    The Monograph is devoted to theoretical discussion of the physical effects, which are most significant for the alternative approach to the problem of controlled thermonuclear fusion (CTF): the MAGO/MTF approach. The book includes the description of the approach, its difference from the major CTF systems—magnetic confinement and inertial confinement systems. General physical methods of the processes simulation in this approach are considered, including plasma transport phenomena and radiation, and the theory of transverse collisionless shock waves, the surface discharges theory, important for such kind of research. Different flows and magneto-hydrodynamic plasma instabilities occurring in the frames of this approach are also considered. In virtue of the general physical essence of the considered phenomena the presented results are applicable to a wide range of plasma physics and hydrodynamics processes. The book is intended for the plasma physics and hydrodynamics specialists, post-graduate students, and senior students-physicists.

  9. The Processes of Inclusion and Exclusion in Physical Education

    DEFF Research Database (Denmark)

    Jensen, Mette Munk; Agergaard, Sine

    2015-01-01

    Existing research on inclusion and exclusion processes in physical education (PE) has particularly focused on exclusion from PE as something being done to students and attributed to specific social categories such as (female) gender, (low) physical skills or (minority) ethnic background. This art......Existing research on inclusion and exclusion processes in physical education (PE) has particularly focused on exclusion from PE as something being done to students and attributed to specific social categories such as (female) gender, (low) physical skills or (minority) ethnic background....... Some students were excluded from PE because they did not have the physical skills and social relations necessary to gain legitimacy from other students. Others chose not to participate because PE was not meaningful to them. This latter type of non-participation from students who experienced lacking...

  10. A new multi-motor drive system based on two-stage direct power converter

    OpenAIRE

    Kumar, Dinesh

    2011-01-01

    The two-stage AC to AC direct power converter is an alternative matrix converter topology, which offers the benefits of sinusoidal input currents and output voltages, bidirectional power flow and controllable input power factor. The absence of any energy storage devices, such as electrolytic capacitors, has increased the potential lifetime of the converter. In this research work, a new multi-motor drive system based on a two-stage direct power converter has been proposed, with two motors c...

  11. Maximally efficient two-stage screening: Determining intellectual disability in Taiwanese military conscripts

    Directory of Open Access Journals (Sweden)

    Chia-Chang Chien

    2009-01-01

    Full Text Available Chia-Chang Chien1, Shu-Fen Huang1,2,3,4, For-Wey Lung1,2,3,41Department of Psychiatry, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan; 2Graduate Institute of Behavioral Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan; 3Department of Psychiatry, National Defense Medical Center, Taipei, Taiwan; 4Calo Psychiatric Center, Pingtung County, TaiwanObjective: The purpose of this study was to apply a two-stage screening method for the large-scale intelligence screening of military conscripts.Methods: We collected 99 conscripted soldiers whose educational levels were senior high school level or lower to be the participants. Every participant was required to take the Wisconsin Card Sorting Test (WCST and the Wechsler Adult Intelligence Scale-Revised (WAIS-R assessments.Results: Logistic regression analysis showed the conceptual level responses (CLR index of the WCST was the most significant index for determining intellectual disability (ID; FIQ ≤ 84. We used the receiver operating characteristic curve to determine the optimum cut-off point of CLR. The optimum one cut-off point of CLR was 66; the two cut-off points were 49 and 66. Comparing the two-stage window screening with the two-stage positive screening, the area under the curve and the positive predictive value increased. Moreover, the cost of the two-stage window screening decreased by 59%.Conclusion: The two-stage window screening is more accurate and economical than the two-stage positive screening. Our results provide an example for the use of two-stage screening and the possibility of the WCST to replace WAIS-R in large-scale screenings for ID in the future.Keywords: intellectual disability, intelligence screening, two-stage positive screening, Wisconsin Card Sorting Test, Wechsler Adult Intelligence Scale-Revised

  12. Planning of process of physical education of students.

    Directory of Open Access Journals (Sweden)

    Pylypey L.P.

    2012-09-01

    Full Text Available Going is considered near the personality oriented system professionally-applied physical training of students. In an experiment 500 students of 1-3 courses took part in age from 17 to 23 years. In research of motivation to employments 52 students took part 3 courses. The results of cross-correlation analysis of computer-integrated indexes of level of physical training are resulted. Aims, functions of structure, typology and principles of physical education, are certain. Progress of professional training trends are exposed. The organizational and methodical aspects of construction of the system of physical education are recommended. Directions of planning of educational process are offered on physical education on the basis of professionally-applied physical training of students. Attention is accented on the necessity of exposure of terms for realization of creative capabilities of teacher, leaders and students.

  13. Two-Stage Robust Security-Constrained Unit Commitment with Optimizable Interval of Uncertain Wind Power Output

    Directory of Open Access Journals (Sweden)

    Dayan Sun

    2017-01-01

    Full Text Available Because wind power spillage is barely considered, the existing robust unit commitment cannot accurately analyze the impacts of wind power accommodation on on/off schedules and spinning reserve requirements of conventional generators and cannot consider the network security limits. In this regard, a novel double-level robust security-constrained unit commitment formulation with optimizable interval of uncertain wind power output is firstly proposed in this paper to obtain allowable interval solutions for wind power generation and provide the optimal schedules for conventional generators to cope with the uncertainty in wind power generation. The proposed double-level model is difficult to be solved because of the invalid dual transform in solution process caused by the coupling relation between the discrete and continuous variables. Therefore, a two-stage iterative solution method based on Benders Decomposition is also presented. The proposed double-level model is transformed into a single-level and two-stage robust interval unit commitment model by eliminating the coupling relation, and then this two-stage model can be solved by Benders Decomposition iteratively. Simulation studies on a modified IEEE 26-generator reliability test system connected to a wind farm are conducted to verify the effectiveness and advantages of the proposed model and solution method.

  14. A Two-Stage Bayesian Network Method for 3D Human Pose Estimation from Monocular Image Sequences

    Directory of Open Access Journals (Sweden)

    Wang Yuan-Kai

    2010-01-01

    Full Text Available Abstract This paper proposes a novel human motion capture method that locates human body joint position and reconstructs the human pose in 3D space from monocular images. We propose a two-stage framework including 2D and 3D probabilistic graphical models which can solve the occlusion problem for the estimation of human joint positions. The 2D and 3D models adopt directed acyclic structure to avoid error propagation of inference. Image observations corresponding to shape and appearance features of humans are considered as evidence for the inference of 2D joint positions in the 2D model. Both the 2D and 3D models utilize the Expectation Maximization algorithm to learn prior distributions of the models. An annealed Gibbs sampling method is proposed for the two-stage method to inference the maximum posteriori distributions of joint positions. The annealing process can efficiently explore the mode of distributions and find solutions in high-dimensional space. Experiments are conducted on the HumanEva dataset with image sequences of walking motion, which has challenges of occlusion and loss of image observations. Experimental results show that the proposed two-stage approach can efficiently estimate more accurate human poses.

  15. A farm-scale pilot plant for biohydrogen and biomethane production by two-stage fermentation

    Directory of Open Access Journals (Sweden)

    R. Oberti

    2013-09-01

    Full Text Available Hydrogen is considered one of the possible main energy carriers for the future, thanks to its unique environmental properties. Indeed, its energy content (120 MJ/kg can be exploited virtually without emitting any exhaust in the atmosphere except for water. Renewable production of hydrogen can be obtained through common biological processes on which relies anaerobic digestion, a well-established technology in use at farm-scale for treating different biomass and residues. Despite two-stage hydrogen and methane producing fermentation is a simple variant of the traditional anaerobic digestion, it is a relatively new approach mainly studied at laboratory scale. It is based on biomass fermentation in two separate, seuqential stages, each maintaining conditions optimized to promote specific bacterial consortia: in the first acidophilic reactorhydrogen is produced production, while volatile fatty acids-rich effluent is sent to the second reactor where traditional methane rich biogas production is accomplished. A two-stage pilot-scale plant was designed, manufactured and installed at the experimental farm of the University of Milano and operated using a biomass mixture of livestock effluents mixed with sugar/starch-rich residues (rotten fruits and potatoes and expired fruit juices, afeedstock mixture based on waste biomasses directly available in the rural area where plant is installed. The hydrogenic and the methanogenic reactors, both CSTR type, had a total volume of 0.7m3 and 3.8 m3 respectively, and were operated in thermophilic conditions (55 2 °C without any external pH control, and were fully automated. After a brief description of the requirements of the system, this contribution gives a detailed description of its components and of engineering solutions to the problems encountered during the plant realization and start-up. The paper also discusses the results obtained in a first experimental run which lead to production in the range of previous

  16. Physical-chemical processes in a protoplanetary cloud

    Science.gov (United States)

    Lavrukhina, Avgusta K.

    1991-01-01

    Physical-chemical processes in a protoplanetary cloud are discussed. The following subject areas are covered: (1) characteristics of the chemical composition of molecular interstellar clouds; (2) properties and physico-chemical process in the genesis of interstellar dust grains; and (3) the isotope composition of volatiles in bodies of the Solar System.

  17. Process evaluation results from the HEALTHY physical education intervention

    Science.gov (United States)

    Process evaluation is an assessment of the implementation of an intervention. A process evaluation component was embedded in the HEALTHY study, a primary prevention trial for Type 2 diabetes implemented over 3 years in 21 middle schools across the United States. The HEALTHY physical education (PE) i...

  18. Contextual Classification of Point Clouds Using a Two-Stage Crf

    Science.gov (United States)

    Niemeyer, J.; Rottensteiner, F.; Soergel, U.; Heipke, C.

    2015-03-01

    In this investigation, we address the task of airborne LiDAR point cloud labelling for urban areas by presenting a contextual classification methodology based on a Conditional Random Field (CRF). A two-stage CRF is set up: in a first step, a point-based CRF is applied. The resulting labellings are then used to generate a segmentation of the classified points using a Conditional Euclidean Clustering algorithm. This algorithm combines neighbouring points with the same object label into one segment. The second step comprises the classification of these segments, again with a CRF. As the number of the segments is much smaller than the number of points, it is computationally feasible to integrate long range interactions into this framework. Additionally, two different types of interactions are introduced: one for the local neighbourhood and another one operating on a coarser scale. This paper presents the entire processing chain. We show preliminary results achieved using the Vaihingen LiDAR dataset from the ISPRS Benchmark on Urban Classification and 3D Reconstruction, which consists of three test areas characterised by different and challenging conditions. The utilised classification features are described, and the advantages and remaining problems of our approach are discussed. We also compare our results to those generated by a point-based classification and show that a slight improvement is obtained with this first implementation.

  19. CO removal by two-stage methanation for polymer electrolyte fuel cell

    Institute of Scientific and Technical Information of China (English)

    Zhiyuan Li; Wanliang Mi; Juan Gong; Zhenlong Lu; Lihao Xu; Qingquan Su

    2008-01-01

    In order to remove CO to achieve lower CO content of below 10 ppm in the CO removal step of reformer for polymer electrolyte fuel cell (PEFC) co-generation systems, CO preferential methanation under various conditions were studied in this paper. Results showed that, with a single kind of catalyst, it was difficult to reach both CO removal depth and CO2 conversion ratio of below 5%. Thus, a two-stage methanation process applying two kinds of catalysts is proposed in this study, that is, one kind of catalyst with relatively low activity and high selectivity for the first stage at higher temperature, and another kind of catalyst with relatively high activity and high selectivity for the second stage at lower temperature. Experimental results showed that at the first stage CO content was decreased from 1% to below 0.1% at 250-300 ℃, and at the second stage to below 10 ppm at 150-185 ℃. CO2 conversion was kept less than 5%. At the same time, influence of inlet CO content and GHSV on CO removal depth was also discussed in this paper.

  20. Dynamic two-stage mechanism of versatile DNA damage recognition by xeroderma pigmentosum group C protein

    Energy Technology Data Exchange (ETDEWEB)

    Clement, Flurina C.; Camenisch, Ulrike; Fei, Jia; Kaczmarek, Nina; Mathieu, Nadine [Institute of Pharmacology and Toxicology, University of Zuerich-Vetsuisse, Winterthurerstrasse 260, CH-8057 Zuerich (Switzerland); Naegeli, Hanspeter, E-mail: naegelih@vetpharm.uzh.ch [Institute of Pharmacology and Toxicology, University of Zuerich-Vetsuisse, Winterthurerstrasse 260, CH-8057 Zuerich (Switzerland)

    2010-03-01

    The recognition and subsequent repair of DNA damage are essential reactions for the maintenance of genome stability. A key general sensor of DNA lesions is xeroderma pigmentosum group C (XPC) protein, which recognizes a wide variety of helix-distorting DNA adducts arising from ultraviolet (UV) radiation, genotoxic chemicals and reactive metabolic byproducts. By detecting damaged DNA sites, this unique molecular sensor initiates the global genome repair (GGR) pathway, which allows for the removal of all the aforementioned lesions by a limited repertoire of excision factors. A faulty GGR activity causes the accumulation of DNA adducts leading to mutagenesis, carcinogenesis, neurological degeneration and other traits of premature aging. Recent findings indicate that XPC protein achieves its extraordinary substrate versatility by an entirely indirect readout strategy implemented in two clearly discernible stages. First, the XPC subunit uses a dynamic sensor interface to monitor the double helix for the presence of non-hydrogen-bonded bases. This initial screening generates a transient nucleoprotein intermediate that subsequently matures into the ultimate recognition complex by trapping undamaged nucleotides in the abnormally oscillating native strand, in a way that no direct contacts are made between XPC protein and the offending lesion itself. It remains to be elucidated how accessory factors like Rad23B, centrin-2 or the UV-damaged DNA-binding complex contribute to this dynamic two-stage quality control process.

  1. A two-stage storage routing model for green roof runoff detention.

    Science.gov (United States)

    Vesuviano, Gianni; Sonnenwald, Fred; Stovin, Virginia

    2014-01-01

    Green roofs have been adopted in urban drainage systems to control the total quantity and volumetric flow rate of runoff. Modern green roof designs are multi-layered, their main components being vegetation, substrate and, in almost all cases, a separate drainage layer. Most current hydrological models of green roofs combine the modelling of the separate layers into a single process; these models have limited predictive capability for roofs not sharing the same design. An adaptable, generic, two-stage model for a system consisting of a granular substrate over a hard plastic 'egg box'-style drainage layer and fibrous protection mat is presented. The substrate and drainage layer/protection mat are modelled separately by previously verified sub-models. Controlled storm events are applied to a green roof system in a rainfall simulator. The time-series modelled runoff is compared to the monitored runoff for each storm event. The modelled runoff profiles are accurate (mean Rt(2) = 0.971), but further characterization of the substrate component is required for the model to be generically applicable to other roof configurations with different substrate.

  2. A New Two-Stage Approach to Short Term Electrical Load Forecasting

    Directory of Open Access Journals (Sweden)

    Dragan Tasić

    2013-04-01

    Full Text Available In the deregulated energy market, the accuracy of load forecasting has a significant effect on the planning and operational decision making of utility companies. Electric load is a random non-stationary process influenced by a number of factors which make it difficult to model. To achieve better forecasting accuracy, a wide variety of models have been proposed. These models are based on different mathematical methods and offer different features. This paper presents a new two-stage approach for short-term electrical load forecasting based on least-squares support vector machines. With the aim of improving forecasting accuracy, one more feature was added to the model feature set, the next day average load demand. As this feature is unknown for one day ahead, in the first stage, forecasting of the next day average load demand is done and then used in the model in the second stage for next day hourly load forecasting. The effectiveness of the presented model is shown on the real data of the ISO New England electricity market. The obtained results confirm the validity advantage of the proposed approach.

  3. Solar Impulsive Hard X-Ray Emission and Two-Stage Electron Acceleration

    Institute of Scientific and Technical Information of China (English)

    Tian-Xi Zhang; Arjun Tan; Shi Tsan Wu

    2006-01-01

    Heating and acceleration of electrons in solar impulsive hard X-ray (HXR) flares are studied according to the two-stage acceleration model developed by Zhang for solar 3Herich events. It is shown that electrostatic H-cyclotron waves can be excited at a parallel phase velocity less than about the electron thermal velocity and thus can significantly heat the electrons (up to 40 MK) through Landau resonance. The preheated electrons with velocities above a threshold are further accelerated to high energies in the flare-acceleration process. The flareproduced electron spectrum is obtained and shown to be thermal at low energies and power law at high energies. In the non-thermal energy range, the spectrum can be double power law if the spectral power index is energy dependent or related. The electron energy spectrum obtained by this study agrees quantitatively with the result derived from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) HXR observations in the flare of 2002 July 23. The total flux and energy flux of electrons accelerated in the solar flare also agree with the measurements.

  4. Stepwise encapsulation and controlled two-stage release system for cis-Diamminediiodoplatinum

    Directory of Open Access Journals (Sweden)

    Chen Y

    2014-06-01

    Full Text Available Yun Chen,1,* Qian Li,1,2,* Qingsheng Wu1 1Department of Chemistry, Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai; 2Shanghai Institute of Quality Inspection and Technical Research, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: cis-Diamminediiodoplatinum (cis-DIDP is a cisplatin-like anticancer drug with higher anticancer activity, but lower stability and price than cisplatin. In this study, a cis-DIDP carrier system based on micro-sized stearic acid was prepared by an emulsion solvent evaporation method. The maximum drug loading capacity of cis-DIDP-loaded solid lipid nanoparticles was 22.03%, and their encapsulation efficiency was 97.24%. In vitro drug release in phosphate-buffered saline (pH =7.4 at 37.5°C exhibited a unique two-stage process, which could prove beneficial for patients with tumors and malignancies. MTT (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay results showed that cis-DIDP released from cis-DIDP-loaded solid lipid nanoparticles had better inhibition activity than cis-DIDP that had not been loaded. Keywords: stearic acid, emulsion solvent evaporation method, drug delivery, cis-DIDP, in vitro

  5. Viroporins, Examples of the Two-Stage Membrane Protein Folding Model

    Directory of Open Access Journals (Sweden)

    Luis Martinez-Gil

    2015-06-01

    Full Text Available Viroporins are small, α-helical, hydrophobic virus encoded proteins, engineered to form homo-oligomeric hydrophilic pores in the host membrane. Viroporins participate in multiple steps of the viral life cycle, from entry to budding. As any other membrane protein, viroporins have to find the way to bury their hydrophobic regions into the lipid bilayer. Once within the membrane, the hydrophobic helices of viroporins interact with each other to form higher ordered structures required to correctly perform their porating activities. This two-step process resembles the two-stage model proposed for membrane protein folding by Engelman and Poppot. In this review we use the membrane protein folding model as a leading thread to analyze the mechanism and forces behind the membrane insertion and folding of viroporins. We start by describing the transmembrane segment architecture of viroporins, including the number and sequence characteristics of their membrane-spanning domains. Next, we connect the differences found among viroporin families to their viral genome organization, and finalize focusing on the pathways used by viroporins in their way to the membrane and on the transmembrane helix-helix interactions required to achieve proper folding and assembly.

  6. A two-stage cascade model of BOLD responses in human visual cortex.

    Directory of Open Access Journals (Sweden)

    Kendrick N Kay

    Full Text Available Visual neuroscientists have discovered fundamental properties of neural representation through careful analysis of responses to controlled stimuli. Typically, different properties are studied and modeled separately. To integrate our knowledge, it is necessary to build general models that begin with an input image and predict responses to a wide range of stimuli. In this study, we develop a model that accepts an arbitrary band-pass grayscale image as input and predicts blood oxygenation level dependent (BOLD responses in early visual cortex as output. The model has a cascade architecture, consisting of two stages of linear and nonlinear operations. The first stage involves well-established computations-local oriented filters and divisive normalization-whereas the second stage involves novel computations-compressive spatial summation (a form of normalization and a variance-like nonlinearity that generates selectivity for second-order contrast. The parameters of the model, which are estimated from BOLD data, vary systematically across visual field maps: compared to primary visual cortex, extrastriate maps generally have larger receptive field size, stronger levels of normalization, and increased selectivity for second-order contrast. Our results provide insight into how stimuli are encoded and transformed in successive stages of visual processing.

  7. TWO-STAGE PRODUCTION SCHEDULING WITH AN OPTION OF OUTSOURCING FROM A REMOTE SUPPLIER

    Institute of Scientific and Technical Information of China (English)

    Xiangtong QI

    2009-01-01

    This paper studies a two-stage production system with n job orders where each job needs two sequential operations. In addition to the two in-house production facilities, the manufacturer has another option of outsourcing some stage-one operations to a remote outside supplier. The jobs with their stage-one operations outsourced are subject to a batch transportation delay from the outside supplier before their respective stage-two operations can be started in-house. The problem is to design an integrated schedule that considers both the in-house production and the outsourcing with the aim of optimally balancing the outsourcing cost and the makespan. The problem is NP-hard. We have developed an optimal algorithm and a heuristic algorithm to solve the problem, and conducted computational experiments to validate our model and algorithms. Our modeling and algorithm framework can be extended to handle other more general cases such as when the outside supplier has a production facility with a different processing efficiency and when there are many outside suppliers on a spot market.

  8. The emergence of the physical world from information processing

    CERN Document Server

    Whitworth, B

    2010-01-01

    This paper links the conjecture that the physical world is a virtual reality to the findings of modern physics. What is usually the subject of science fiction is here proposed as a scientific theory open to empirical evaluation. We know from physics how the world behaves, and from computing how information behaves, so whether the physical world arises from ongoing information processing is a question science can evaluate. A prima facie case for the virtual reality conjecture is presented. If a photon is a pixel on a multi-dimensional grid that gives rise to space, the speed of light could reflect its refresh rate. If mass, charge and energy all arise from processing, the many conservation laws of physics could reduce to a single law of dynamic information conservation. If the universe is a virtual reality, then its big bang creation could be simply when the system was booted up. Deriving core physics from information processing could reconcile relativity and quantum theory, with the former how processing crea...

  9. Combustion of coked sand in a two-stage fluidized bed system

    Energy Technology Data Exchange (ETDEWEB)

    Coronella, C.J.; Seader, J.D. (University of Utah, Salt Lake City, UT (USA). Dept. of Chemical Engineering)

    1992-02-01

    An advanced multiple-stage fluidized bed reactor system has been devised for the energy-efficient extraction and conversion, from tar sand, of bitumen into synthetic crude oil. The reactor consists of four fluidized beds arranged as stages in series with respect to flow of sand. In the first stage, tar sands are heated, causing the bitumen to pyrolyse into coke, which is deposited on the sand, and gas, which is mostly condensed into oil. The coke is partially combusted with air or enriched oxygen in the second stage, which is thermally coupled to the first stage by multiple vertical heat pipes. Combustion is completed adiabatically in the third stage and heat recovery from the sand is carried out in the fourth stage. By conducting the coke combustion in two stages in this manner, the overall reactor residence time to produce clean sand is greatly reduced from that for a single combustion stage. Laboratory experimental studies have confirmed the ability to operate and control the two thermally coupled stages. The two-phase bubbling bed model of Grace, amended to account for bubble growth in the axial direction, has been adopted to model the mass transfer and fluid mechanics of the fluidized beds. The model for the first and second combustion stages is complete. Predictions for exit reactor conditions at various operating conditions are in reasonable agreement with experimental observations. The operating parameters have been found to exert a much greater influence on the predictions of the model than do the values of the physical parameters, indicating a desirable degree of reactor stability. Extension of the model to the pyrolysis and heat recovery stages will permit the optimization of the reactor configuration and operating conditions. 26 refs., 6 figs.

  10. Student-centred instruction and learning processes in physics

    Science.gov (United States)

    Welzel, Manuela

    1997-09-01

    During the 1970s, student-centred instruction—that is, “play orientation in physics education” (Spielorientierter Unterricht)—was at the centre of curriculum development at the Institute of Physics Education in Bremen. During the past decade, we investigated this kind of instruction with a particular focus on students' learning processes using a situated cognition perspective. Our research group at the Institute conducted several empirical studies of physics learning for different age groups. The aim of these case studies was to construct detailed understandings of how individual learning processes unfold. On the basis of these studies, we attempt to design physics lessons more effectively than they have been in the past. This paper exemplifies our approach providing information about the theoretical and methodological frameworks, the main outcomes of our studies; and reflections about the possibilities for “more effective” student-centred instruction.

  11. Microbial community structure and dynamics in two-stage vs single-stage thermophilic anaerobic digestion of mixed swine slurry and market bio-waste.

    Science.gov (United States)

    Merlino, Giuseppe; Rizzi, Aurora; Schievano, Andrea; Tenca, Alberto; Scaglia, Barbara; Oberti, Roberto; Adani, Fabrizio; Daffonchio, Daniele

    2013-04-15

    The microbial community of a thermophilic two-stage process was monitored during two-months operation and compared to a conventional single-stage process. Qualitative and quantitative microbial dynamics were analysed by Denaturing Gradient Gel Electrophoresis (DGGE) and real-time PCR techniques, respectively. The bacterial community was dominated by heat-shock resistant, spore-forming clostridia in the two-stage process, whereas a more diverse and dynamic community (Firmicutes, Bacteroidetes, Synergistes) was observed in the single-stage process. A significant evolution of bacterial community occurred over time in the acidogenic phase of the two-phase process with the selection of few dominant species associated to stable hydrogen production. The archaeal community, dominated by the acetoclastic Methanosarcinales in both methanogen reactors, showed a significant diversity change in the single-stage process after a period of adaptation to the feeding conditions, compared to a constant stability in the methanogenic reactor of the two-stage process. The more diverse and dynamic bacterial and archaeal community of single-stage process compared to the two-stage process accounted for the best degradation activity, and consequently the best performance, in this reactor. The microbiological perspective proved a useful tool for a better understanding and comparison of anaerobic digestion processes.

  12. Remoção de matéria orgânica, de nutrientes e de coliformes no processo anaeróbio em dois estágios (reator compartimentado seguido de reator UASB para o tratamento de águas residuárias de suinocultura Organic matter, nutrients and coliforms removal in two-stage anaerobic process (anaerobic baffled reactor followed by UASB reactor for swine wastewater treatment

    Directory of Open Access Journals (Sweden)

    Mário S. de Abreu Neto

    2009-03-01

    Full Text Available Neste trabalho, avaliou-se o efeito das águas residuárias de suinocultura, com concentrações médias de sólidos suspensos totais variando de 4.591 a 13.001 mg L-1, no desempenho de processo anaeróbio, em dois estágios, compostos por reator compartimentado (ABR e reator de fluxo ascendente com manta de lodo (UASB, instalados em série, em escala- -piloto (volumes de 530 e 120 L, respectivamente, submetidos a tempos de detenção hidráulica (TDH de 60; 36 e 24 h no primeiro reator, e de 13,6; 8,2 e 5,4 h no segundo reator. As eficiências médias de remoção de DQOtotal variaram de 69 a 84% no reator ABR e de 39 a 58% no reator UASB, resultando em valores médios de 87 a 94% para o sistema de tratamento anaeróbio em dois estágios, com carga orgânica volumétrica (COV na faixa de 11,5 a 18,0 g DQOtotal (L d-1 no reator ABR, e de 4,2 a 13,4 g DQOtotal (L d-1 no reator UASB. A produção volumétrica máxima de metano de 0,227 m³ CH4 (m³ reator d-1 ocorreu no reator UASB, com COV de 10,6 g DQOtotal (L d-1 e TDH de 5,4 h. As maiores eficiências de remoção de coliformes totais e termotolerantes (99,7%, DQOdiss (94%, SST (96%, NTK (71%, P-total (61% e outros nutrientes, no sistema de tratamento anaeróbio em dois estágios, foram obtidas com o TDH de 73,6 h e temperatura climatológica média de 24,6 °C, aplicando-se a menor COV (de 11,5 g DQOtotal (L d-1 no reator ABR, e de 4,2 g DQOtotal (L d-1 no reator UASB com a maior concentração de SST do afluente (13.001 mg L-1.In this work it was evaluated the effect of swine wastewater with mean total suspended solid (TSS concentration ranging from 4.591 to 13.001 mg L-1 on the performance of the anaerobic process in two stages composed of anaerobic baffled reactors (ABR and an upflow sludge blanket reactor (UASB, installed in series, in pilot scale testing (volumes of 530 and 120 L, respectively and with hydraulic detention times (HDT of 60; 36 and 24 h in the ABR reactor and 13.6; 8.2 and

  13. Physics-based signal processing algorithms for micromachined cantilever arrays

    Science.gov (United States)

    Candy, James V; Clague, David S; Lee, Christopher L; Rudd, Robert E; Burnham, Alan K; Tringe, Joseph W

    2013-11-19

    A method of using physics-based signal processing algorithms for micromachined cantilever arrays. The methods utilize deflection of a micromachined cantilever that represents the chemical, biological, or physical element being detected. One embodiment of the method comprises the steps of modeling the deflection of the micromachined cantilever producing a deflection model, sensing the deflection of the micromachined cantilever and producing a signal representing the deflection, and comparing the signal representing the deflection with the deflection model.

  14. Physical and chemical characterization of bioaerosols - Implications for nucleation processes

    Science.gov (United States)

    Ariya, P. A.; Sun, J.; Eltouny, N. A.; Hudson, E. D.; Hayes, C. T.; Kos, G.

    The importance of organic compounds in the oxidative capacity of the atmosphere, and as cloud condensation and ice-forming nuclei, has been recognized for several decades. Organic compounds comprise a significant fraction of the suspended matter mass, leading to local (e.g. toxicity, health hazards) and global (e.g. climate change) impacts. The state of knowledge of the physical chemistry of organic aerosols has increased during the last few decades. However, due to their complex chemistry and the multifaceted processes in which they are involved, the importance of organic aerosols, particularly bioaerosols, in driving physical and chemical atmospheric processes is still very uncertain and poorly understood. Factors such as solubility, surface tension, chemical impurities, volatility, morphology, contact angle, deliquescence, wettability, and the oxidation process are pivotal in the understanding of the activation processes of cloud droplets, and their chemical structures, solubilities and even the molecular configuration of the microbial outer membrane, all impact ice and cloud nucleation processes in the atmosphere. The aim of this review paper is to assess the current state of knowledge regarding chemical and physical characterization of bioaerosols with a focus on those properties important in nucleation processes. We herein discuss the potential importance (or lack thereof) of physical and chemical properties of bioaerosols and illustrate how the knowledge of these properties can be employed to study nucleation processes using a modeling exercise. We also outline a list of major uncertainties due to a lack of understanding of the processes involved or lack of available data. We will also discuss key issues of atmospheric significance deserving future physical chemistry research in the fields of bioaerosol characterization and microphysics, as well as bioaerosol modeling. These fundamental questions are to be addressed prior to any definite conclusions on the

  15. Method of oxygen-enriched two-stage underground coal gasification

    Institute of Scientific and Technical Information of China (English)

    Liu Hongtao; Chen Feng; Pan Xia; Yao Kai; Liu Shuqin

    2011-01-01

    Two-stage underground coal gasification was studied to improve the caloric value of the syngas and to extend gas production times. A model test using the oxygen-enriched two-stage coal gasification method was carried out. The composition of the gas produced, the time ratio of the two stages, and the role of the temperature field were analysed. The results show that oxygen-enriched two-stage gasification shortens the time of the first stage and prolongs the time of the second stage. Feed oxygen concentrations of 30%,35%, 40%, 45%, 60%, or 80% gave time ratios (first stage to second stage) of 1:0.12, 1:0.21, 1:0.51, 1:0.64,1:0.90, and 1:4.0 respectively. Cooling rates of the temperature field after steam injection decreased with time from about 19.1-27.4 ℃/min to 2.3-6.8 ℃/min. But this rate increased with increasing oxygen concentrations in the first stage. The caloric value of the syngas improves with increased oxygen concentration in the first stage. Injection of 80% oxygen-enriched air gave gas with the highest caloric value and also gave the longest production time. The caloric value of the gas obtained from the oxygenenriched two-stage gasification method lies in the range from 5.31 MJ/Nm3 to 10.54 MJ/Nm3.

  16. High magnetostriction parameters for low-temperature sintered cobalt ferrite obtained by two-stage sintering

    Energy Technology Data Exchange (ETDEWEB)

    Khaja Mohaideen, K.; Joy, P.A., E-mail: pa.joy@ncl.res.in

    2014-12-15

    From the studies on the magnetostriction characteristics of two-stage sintered polycrystalline CoFe{sub 2}O{sub 4} made from nanocrystalline powders, it is found that two-stage sintering at low temperatures is very effective for enhancing the density and for attaining higher magnetostriction coefficient. Magnetostriction coefficient and strain derivative are further enhanced by magnetic field annealing and relatively larger enhancement in the magnetostriction parameters is obtained for the samples sintered at lower temperatures, after magnetic annealing, despite the fact that samples sintered at higher temperatures show larger magnetostriction coefficients before annealing. A high magnetostriction coefficient of ∼380 ppm is obtained after field annealing for the sample sintered at 1100 °C, below a magnetic field of 400 kA/m, which is the highest value so far reported at low magnetic fields for sintered polycrystalline cobalt ferrite. - Highlights: • Effect of two-stage sintering on the magnetostriction characteristics of CoFe{sub 2}O{sub 4} is studied. • Two-stage sintering is very effective for enhancing the density and the magnetostriction parameters. • Higher magnetostriction for samples sintered at low temperatures and after magnetic field annealing. • Highest reported magnetostriction of 380 ppm at low fields after two-stage, low-temperature sintering.

  17. 13 K thermally coupled two-stage Stirling-type pulse tube refrigerator

    Institute of Scientific and Technical Information of China (English)

    TANG Ke; CHEN Guobang; THUMMES Günter

    2005-01-01

    Stirling-type pulse tube refrigerators have attracted academic and commercial interest in recent years due to their more compact configuration and higher efficiency than those of G-M type pulse tube refrigerators. In order to achieve a no-load cooling temperature below 20 K, a thermally coupled two-stage Stirling-type pulse tube refrigerator has been built. The thermally coupled arrangement was expected to minimize the interference between the two stages and to simplify the adjustment and optimization of the phase shifters. A no-load cooling temperature of 14.97 K has been realized with the two-stage cooler driven by one linear compressor of 200 W electric input. When the two stages are driven by two compressors respectively, with total electric input of 400 W, the prototype has attained a no-load cooling temperature of 12.96 K, which is the lowest temperature ever reported with two-stage Stirling-type pulse tube refrigerators.

  18. Pilot plant testing of IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor

    Energy Technology Data Exchange (ETDEWEB)

    Rehmat, A.; Mensinger, M.C. [Institute of Gas Technology, Chicago, IL (United States); Richardson, T.L. [Environmental Protection Agency, Cincinnati, OH (United States)

    1993-12-31

    The Institute of Gas Technology (IGT) is conducting a multi-year experimental program to develop and test, through pilot-scale operation, IGT`s two-stage fluidized-bed/cyclonic agglomerating combustor (AGGCOM). The AGGCOM process is based on combining the fluidized-bed agglomeration and gasification technology with the cyclonic combustion technology, both of which have been developed at IGT over many years. AGGCOM is a unique and extremely flexible combustor that can operate over a wide range of conditions in the fluidized-bed first stage from low temperature (desorption) to high temperature (agglomeration), including gasification of high-energy-content wastes. The ACCCOM combustor can easily and efficiently destroy solid, liquid, and gaseous organic wastes, while isolating solid inorganic contaminants within an essentially non-leachable glassy matrix, suitable for disposal in ordinary landfills. Fines elutriated from the first stage are captured by a high-efficiency cyclone and returned to the fluidized bed for ultimate incorporation into the agglomerates. Intense mixing in the second-stage cyclonic combustor ensures high destruction and removal efficiencies (DRE) for organic compounds that may be present in the feed material. This paper presents an overview of the experimental development of the AGGCOM process and progress made to date in designing, constructing, and operating the 6-ton/day AGGCOM pilot plant. Results of the bench-scale tests conducted to determine the operating conditions necessary to agglomerate a soil were presented at the 1991 Incineration Conference. On-site construction of the AGGCOM pilot plant was initiated in August 1992 and completed at the end of March 1993, with shakedown testing following immediately thereafter. The initial tests in the AGGCOM pilot plant will focus on the integrated operation of both stages of the combustor and will be conducted with ``clean`` topsoil.

  19. Design and construction of the X-2 two-stage free piston driven expansion tube

    Science.gov (United States)

    Doolan, Con

    1995-01-01

    This report outlines the design and construction of the X-2 two-stage free piston driven expansion tube. The project has completed its construction phase and the facility has been installed in the new impulsive research laboratory where commissioning is about to take place. The X-2 uses a unique, two-stage driver design which allows a more compact and lower overall cost free piston compressor. The new facility has been constructed in order to examine the performance envelope of the two-stage driver and how well it couple to sub-orbital and super-orbital expansion tubes. Data obtained from these experiments will be used for the design of a much larger facility, X-3, utilizing the same free piston driver concept.

  20. Analysis of performance and optimum configuration of two-stage semiconductor thermoelectric module

    Institute of Scientific and Technical Information of China (English)

    Li Kai-Zhen; Liang Rui-Sheng; Wei Zheng-Jun

    2008-01-01

    In this paper, the theoretical analysis and simulating calculation were conducted for a basic two-stage semiconductor thermoelectric module, which contains one thermocouple in the second stage and several thermocouples in the first stage. The study focused on the configuration of the two-stage semiconductor thermoelectric cooler, especially investigating the influences of some parameters, such as the current I1 of the first stage, the area A1 of every thermocouple and the number n of thermocouples in the first stage, on the cooling performance of the module. The obtained results of analysis indicate that changing the current I1 of the first stage, the area A1 of thcrmocouples and the number n of thermocouples in the first stage can improve the cooling performance of the module. These results can be used to optimize the configuration of the two-stage semiconductor thermoelectric module and provide guides for the design and application of thermoelectric cooler.

  1. Two-Stage Revision Anterior Cruciate Ligament Reconstruction: Bone Grafting Technique Using an Allograft Bone Matrix.

    Science.gov (United States)

    Chahla, Jorge; Dean, Chase S; Cram, Tyler R; Civitarese, David; O'Brien, Luke; Moulton, Samuel G; LaPrade, Robert F

    2016-02-01

    Outcomes of primary anterior cruciate ligament (ACL) reconstruction have been reported to be far superior to those of revision reconstruction. However, as the incidence of ACL reconstruction is rapidly increasing, so is the number of failures. The subsequent need for revision ACL reconstruction is estimated to occur in up to 13,000 patients each year in the United States. Revision ACL reconstruction can be performed in one or two stages. A two-stage approach is recommended in cases of improper placement of the original tunnels or in cases of unacceptable tunnel enlargement. The aim of this study was to describe the technique for allograft ACL tunnel bone grafting in patients requiring a two-stage revision ACL reconstruction.

  2. The CSS and The Two-Staged Methods for Parameter Estimation in SARFIMA Models

    Directory of Open Access Journals (Sweden)

    Erol Egrioglu

    2011-01-01

    Full Text Available Seasonal Autoregressive Fractionally Integrated Moving Average (SARFIMA models are used in the analysis of seasonal long memory-dependent time series. Two methods, which are conditional sum of squares (CSS and two-staged methods introduced by Hosking (1984, are proposed to estimate the parameters of SARFIMA models. However, no simulation study has been conducted in the literature. Therefore, it is not known how these methods behave under different parameter settings and sample sizes in SARFIMA models. The aim of this study is to show the behavior of these methods by a simulation study. According to results of the simulation, advantages and disadvantages of both methods under different parameter settings and sample sizes are discussed by comparing the root mean square error (RMSE obtained by the CSS and two-staged methods. As a result of the comparison, it is seen that CSS method produces better results than those obtained from the two-staged method.

  3. A two-stage subsurface vertical flow constructed wetland for high-rate nitrogen removal.

    Science.gov (United States)

    Langergraber, Guenter; Leroch, Klaus; Pressl, Alexander; Rohrhofer, Roland; Haberl, Raimund

    2008-01-01

    By using a two-stage constructed wetland (CW) system operated with an organic load of 40 gCOD.m(-2).d(-1) (2 m2 per person equivalent) average nitrogen removal efficiencies of about 50% and average nitrogen elimination rates of 980 g N.m(-2).yr(-1) could be achieved. Two vertical flow beds with intermittent loading have been operated in series. The first stage uses sand with a grain size of 2-3.2 mm for the main layer and has a drainage layer that is impounded; the second stage sand with a grain size of 0.06-4 mm and a drainage layer with free drainage. The high nitrogen removal can be achieved without recirculation thus it is possible to operate the two-stage CW system without energy input. The paper shows performance data for the two-stage CW system regarding removal of organic matter and nitrogen for the two year operating period of the system. Additionally, its efficiency is compared with the efficiency of a single-stage vertical flow CW system designed and operated according to the Austrian design standards with 4 m2 per person equivalent. The comparison shows that a higher effluent quality could be reached with the two-stage system although the two-stage CW system is operated with the double organic load or half the specific surface area requirement, respectively. Another advantage is that the specific investment costs of the two-stage CW system amount to 1,200 EUR per person (without mechanical pre-treatment) and are only about 60% of the specific investment costs of the singe-stage CW system. IWA Publishing 2008.

  4. Two Stage Fully Differential Sample and Hold Circuit Using .18µm Technology

    Directory of Open Access Journals (Sweden)

    Dharmendra Dongardiye

    2014-05-01

    Full Text Available This paper presents a well-established Fully Differential sample & hold circuitry, implemented in 180-nm CMOS technology. In this two stage method the first stage give us very high gain and second stage gives large voltage swing. The proposed opamp provides 149MHz unity-gain bandwidth , 78 degree phase margin and a differential peak to peak output swing more than 2.4v. using the improved fully differential two stage operational amplifier of 76.7dB gain. Although the sample and hold circuit meets the requirements of SNR specifications.

  5. One-stage and two-stage penile buccal mucosa urethroplasty

    Directory of Open Access Journals (Sweden)

    G. Barbagli

    2016-03-01

    Full Text Available The paper provides the reader with the detailed description of current techniques of one-stage and two-stage penile buccal mucosa urethroplasty. The paper provides the reader with the preoperative patient evaluation paying attention to the use of diagnostic tools. The one-stage penile urethroplasty using buccal mucosa graft with the application of glue is preliminary showed and discussed. Two-stage penile urethroplasty is then reported. A detailed description of first-stage urethroplasty according Johanson technique is reported. A second-stage urethroplasty using buccal mucosa graft and glue is presented. Finally postoperative course and follow-up are addressed.

  6. Development of a linear compressor for two-stage pulse tube cryocoolers

    Institute of Scientific and Technical Information of China (English)

    Peng-da YAN; Wei-li GAO; Guo-bang CHEN

    2009-01-01

    A valveless linear compressor was built up to drive a self-made two-stage pulse tube cryocooler. With a designed maximum swept volume of 60 cm~3, the compressor can provide the cryocooler with a pressure volume (PV) power of 400 W.Preliminary measurements of the compressor indicated that both an efficiency of 35%~55% and a pressure ratio of 1.3~1.4 could be obtained. The two-stage pulse tube cryocooler driven by this compressor achieved the lowest temperature of 14.2 K.

  7. Two-stage pH Control Mode in Batch Fermentation of a Novel Bioflocculant from Corynebacterium Glutamicum

    Institute of Scientific and Technical Information of China (English)

    HE Ning; WU Xiao-jie; DENG Xu; LU Ying-hua; LI Qing-biao

    2004-01-01

    The effect of pH of the fermentation medium on cell growth and the production of a novel bioflocculant (named REA-11 ) by Corynebacterium glutamicum CCTCC M201005 were investigated. The maximum biomass (2.23 g/L) and flocculating activity (142.2 U/mL) were simultaneously obtained at the 14th hour when the pH value of the culture medium was maintained at 7.0 during the whole fermentation process. The production of REA-11 kept on a trend of increase till the later phase of fermentation process, which resulted in the ultimate flocculating activity of the culture broth to enhance to nearly 100 U/mL at pH 6.0. A twostage pH control mode was adopted in REA-11 production in which the pH value of the culture medium was controlled at 7.0 during the first 14 h, then decreased to 6.0 that was maintained until the end of the fermentation process. With the two-stage pH control mode, the maximum flocculating activity reached 178.8 U/mL which was 30% higher than that obtained under the condition of pH 7.0 and the biomass enhanced about 15%. Compared with the fermentation process without pH control, REA-11 production and cell growth via the two-stage pH control mode increased 80% and 25%, respectively.

  8. The role of quantum measurements in physical processes and protocols

    Science.gov (United States)

    Cruikshank, Benjamin; Jacobs, Kurt

    2017-09-01

    In this mainly pedagogical article, we discuss under what circumstances measurements play a special role in quantum processes. In particular, we discuss the following facts that appear to be a common area of confusion. (i) From a fundamental point of view, measurements play no special role whatsoever: all dynamics that can be generated by measurements can be generated by unitary processes (for which post-selection is no exception). (ii) From a purely physical point of view, measurements are not ‘outside’ of quantum mechanics. (iii) The only difference between the abilities of measurement-based protocols and unitary circuits for quantum computing comes from practical (technology dependent) constraints. We emphasise the importance of distinguishing between differences that are (i) fundamental but without physical import; (ii) fundamental and possess physical import; and (iii) are not fundamental but have practical import. We also emphasise the importance of separating theoretical and experimental elements of measurement, primarily projection and amplification, which are physically very different. Note that since we are concerned with facts regarding physical processes, this article has little if anything to do with interpretations of quantum mechanics.

  9. Physical Processes in the Far and Near Space

    CERN Document Server

    B., Dubovichenko S; M, Chechin L

    2010-01-01

    The book examines some of the questions of modern cosmology, the physics of atmospheric phenomena, the physics of quasi-particles and atomic nuclei in the Universe. It consists of three parts, each discusses the theoretical problems of various subjects of cosmic physics. The first part examines the physics of the expanding Universe, with emphasis on the content of the latest revolution in cosmology. It is today well established that the universe is dominated by a vacuum that exceeds the density of baryonic forms of cosmic matter, that the dynamics of the cosmic expansion controls the vacuum antigravity and, finally, that the cosmological expansion is accelerating. In the second part we investigate the processes leading to the electrization of gas fluxes in the solar atmosphere and the generation of neutrons in the active regions of its atmosphere, issues of electrization of thunderstorm clouds in the troposphere of the Earth, the formation and development of noctilucent clouds in the area of the mesosphere. I...

  10. First Law Analysis of a Two-stage Ejector-vapor Compression Refrigeration Cycle working with R404A

    National Research Council Canada - National Science Library

    Feiza Memet; Daniela-Elena Mitu

    2011-01-01

    The traditional two-stage vapor compression refrigeration cycle might be replaced by a two-stage ejector-vapor compression refrigeration cycle if it is aimed the decrease of irreversibility during expansion...

  11. The s Process: Nuclear Physics, Stellar Models, Observations

    CERN Document Server

    Kaeppeler, Franz; Bisterzo, Sara; Aoki, Wako

    2010-01-01

    Nucleosynthesis in the s process takes place in the He burning layers of low mass AGB stars and during the He and C burning phases of massive stars. The s process contributes about half of the element abundances between Cu and Bi in solar system material. Depending on stellar mass and metallicity the resulting s-abundance patterns exhibit characteristic features, which provide comprehensive information for our understanding of the stellar life cycle and for the chemical evolution of galaxies. The rapidly growing body of detailed abundance observations, in particular for AGB and post-AGB stars, for objects in binary systems, and for the very faint metal-poor population represents exciting challenges and constraints for stellar model calculations. Based on updated and improved nuclear physics data for the s-process reaction network, current models are aiming at ab initio solution for the stellar physics related to convection and mixing processes. Progress in the intimately related areas of observations, nuclear...

  12. Two-Stage Multi-Objective Collaborative Scheduling for Wind Farm and Battery Switch Station

    Directory of Open Access Journals (Sweden)

    Zhe Jiang

    2016-10-01

    Full Text Available In order to deal with the uncertainties of wind power, wind farm and electric vehicle (EV battery switch station (BSS were proposed to work together as an integrated system. In this paper, the collaborative scheduling problems of such a system were studied. Considering the features of the integrated system, three indices, which include battery swapping demand curtailment of BSS, wind curtailment of wind farm, and generation schedule tracking of the integrated system are proposed. In addition, a two-stage multi-objective collaborative scheduling model was designed. In the first stage, a day-ahead model was built based on the theory of dependent chance programming. With the aim of maximizing the realization probabilities of these three operating indices, random fluctuations of wind power and battery switch demand were taken into account simultaneously. In order to explore the capability of BSS as reserve, the readjustment process of the BSS within each hour was considered in this stage. In addition, the stored energy rather than the charging/discharging power of BSS during each period was optimized, which will provide basis for hour-ahead further correction of BSS. In the second stage, an hour-ahead model was established. In order to cope with the randomness of wind power and battery swapping demand, the proposed hour-ahead model utilized ultra-short term prediction of the wind power and the battery switch demand to schedule the charging/discharging power of BSS in a rolling manner. Finally, the effectiveness of the proposed models was validated by case studies. The simulation results indicated that the proposed model could realize complement between wind farm and BSS, reduce the dependence on power grid, and facilitate the accommodation of wind power.

  13. Two-stage re-estimation adaptive design: a simulation study

    Directory of Open Access Journals (Sweden)

    Francesca Galli

    2013-10-01

    Full Text Available Background: adaptive clinical trial design has been proposed as a promising new approach to improve the drug discovery process. Among the many options available, adaptive sample size re-estimation is of great interest mainly because of its ability to avoid a large ‘up-front’ commitment of resources. In this simulation study, we investigate the statistical properties of two-stage sample size re-estimation designs in terms of type I error control, study power and sample size, in comparison with the fixed-sample study.Methods: we simulated a balanced two-arm trial aimed at comparing two means of normally distributed data, using the inverse normal method to combine the results of each stage, and considering scenarios jointly defined by the following factors: the sample size re-estimation method, the information fraction, the type of group sequential boundaries and the use of futility stopping. Calculations were performed using the statistical software SAS™ (version 9.2.Results: under the null hypothesis, any type of adaptive design considered maintained the prefixed type I error rate, but futility stopping was required to avoid the unwanted increase in sample size. When deviating from the null hypothesis, the gain in power usually achieved with the adaptive design and its performance in terms of sample size were influenced by the specific design options considered.Conclusions: we show that adaptive designs incorporating futility stopping, a sufficiently high information fraction (50-70% and the conditional power method for sample size re-estimation have good statistical properties, which include a gain in power when trial results are less favourable than anticipated. 

  14. CFD Modelling of Bore Erosion in Two-Stage Light Gas Guns

    Science.gov (United States)

    Bogdanoff, D. W.

    1998-01-01

    A well-validated quasi-one-dimensional computational fluid dynamics (CFD) code for the analysis of the internal ballistics of two-stage light gas guns is modified to explicitly calculate the ablation of steel from the gun bore and the incorporation of the ablated wall material into the hydrogen working cas. The modified code is used to model 45 shots made with the NASA Ames 0.5 inch light gas gun over an extremely wide variety of gun operating conditions. Good agreement is found between the experimental and theoretical piston velocities (maximum errors of +/-2% to +/-6%) and maximum powder pressures (maximum errors of +/-10% with good igniters). Overall, the agreement between the experimental and numerically calculated gun erosion values (within a factor of 2) was judged to be reasonably good, considering the complexity of the processes modelled. Experimental muzzle velocities agree very well (maximum errors of 0.5-0.7 km/sec) with theoretical muzzle velocities calculated with loading of the hydrogen gas with the ablated barrel wall material. Comparison of results for pump tube volumes of 100%, 60% and 40% of an initial benchmark value show that, at the higher muzzle velocities, operation at 40% pump tube volume produces much lower hydrogen loading and gun erosion and substantially lower maximum pressures in the gun. Large muzzle velocity gains (2.4-5.4 km/sec) are predicted upon driving the gun harder (that is, upon using, higher powder loads and/or lower hydrogen fill pressures) when hydrogen loading is neglected; much smaller muzzle velocity gains (1.1-2.2 km/sec) are predicted when hydrogen loading is taken into account. These smaller predicted velocity gains agree well with those achieved in practice. CFD snapshots of the hydrogen mass fraction, density and pressure of the in-bore medium are presented for a very erosive shot.

  15. Enhancement of pyruvate production by Torulopsis glabrata using a two-stage oxygen supply control strategy.

    Science.gov (United States)

    Li, Y; Hugenholtz, J; Chen, J; Lun, S-Y

    2002-10-01

    The effect of agitation speeds on the performance of producing pyruvate by a multi-vitamin auxotrophic yeast, Torulopsis glabrata, was investigated in batch fermentation. High pyruvate yield on glucose (0.797 g g(-1)) was achieved under high agitation speed (700 rpm), but the glucose consumption rate was rather low (1.14 g l(-1) h(-1)). Glucose consumption was enhanced under low agitation speed (500 rpm), but the pyruvate yield on glucose decreased to 0.483 g g(-1). Glycerol production was observed under low agitation speed and decreased with increasing agitation speed. Based on process analysis and carbon flux distribution calculation, a two-stage oxygen supply control strategy was proposed, in which the agitation speed was controlled at 700 rpm in the first 16 h and then switched to 500 rpm. This was experimentally proven to be successful. Relatively high concentration of pyruvate (69.4 g l(-1)), high pyruvate yield on glucose (0.636 g g(-1)), and high glucose consumption rate (1.95 g l(-1)h(-1)) were achieved by applying this strategy. The productivity (1.24 g l(-1) h(-1)) was improved by 36%, 23% and 31%, respectively, compared with fermentations in which agitation speeds were kept constant at 700 rpm, 600 rpm, and 500 rpm. Experimental results indicate that the difference between the performances for producing pyruvate under a favorable state of oxygen supply (dissolved oxygen concentration >50%) was caused by the different regeneration pathways of NADH generated from glycolysis.

  16. Reflector antenna analysis using physical optics on Graphics Processing Units

    DEFF Research Database (Denmark)

    Borries, Oscar Peter; Sørensen, Hans Henrik Brandenborg; Dammann, Bernd

    2014-01-01

    The Physical Optics approximation is a widely used asymptotic method for calculating the scattering from electrically large bodies. It requires significant computational work and little memory, and is thus well suited for application on a Graphics Processing Unit. Here, we investigate...... the performance of an implementation and demonstrate that while there are some implementational pitfalls, a careful implementation can result in impressive improvements....

  17. Multiscale physical processes of fine sediment in an estuary

    NARCIS (Netherlands)

    Wan, Y.

    2015-01-01

    This study presented in this book investigates micro- and macro- scale physical processes of a large-scale fine sediment estuarine system with a moderate tidal range as well as a highly seasonal-varying freshwater inflow. Based on a series measured, experimented and modeled results, the research hig

  18. Brownian Motion as a Limit to Physical Measuring Processes

    DEFF Research Database (Denmark)

    Niss, Martin

    2016-01-01

    and received widespread recognition, but his way of modeling the system was contested by his contemporaries. With the more embracing notion of noise that developed during and after World War II, Ising’s conclusion was reinterpreted as showing that noise puts a limit on physical measurement processes. Hence...

  19. Greenhouse climate : from physical processes to a dynamic model

    NARCIS (Netherlands)

    Bot, G.P.A.

    1983-01-01

    In this thesis greenhouse climate has been studied as the set of environmental conditions in a greenhouse in so far as they affect crop growth and development. In chapter 2 this set has been defined in terms of temperatures and vapour pressures. Moreover we have indicated which physical processes

  20. Upper ocean physical processes in the Tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, L.V.G.; Ram, P.S.

    This monograph is the outcome of an attempt by the authors to present a synthesis of the studies on physical processes in the Tropical Indian Ocean (TIO) in relation to air-sea interaction, monsoon/climate variability and biological productivity...

  1. A two-stage bio hydrogen process for energy generation from municipal solid wastes

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo-Benitez, J. a.; Poggi-Varaldo, H. M.

    2009-07-01

    Energy supply and disposal of solid wastes are two big challenges that great cities face at the present time. Several experts have shown that hydrogen is the fuel of the future, due to their high energy content (three times more than that of the gasoline) and its clean combustion. (Author)

  2. Heat Transfer Processes for the Thermal Energy Balance of Organisms. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Stevenson, R. D.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module describes heat transfer processes involved in the exchange of heat…

  3. Microbial decolorization of reactive black-5 in a two-stage anaerobic-aerobic reactor using acclimatized activated textile sludge.

    Science.gov (United States)

    Mohanty, Sagarika; Dafale, Nishant; Rao, Nageswara Neti

    2006-10-01

    A two-stage anaerobic-aerobic treatment process based on mixed culture of bacteria isolated from textile dye effluent was used to degrade reactive black 5 dye (RB-5). The anaerobic step was studied in more detail by varying the dye concentration from 100 to 3000 mg l(-1). The results showed that major decolorization was achieved during the anaerobic process. The time required for decolorization by > 90% increased as the concentration of the dye increased. It was also found that maintaining dissolved oxygen (DO) concentration below 0.5 mg l(-1 )and addition of a co-substrate viz., glucose, facilitates anaerobic decolorization reaction remarkably. An attempt was made to identify the metabolites formed in anaerobic process by using high performance liquid chromatography (HPLC) and UV-VIS spectrophotometry. A plate assay was performed for the detection of dominant decolorizing bacteria. Only a few bacterial colonies with high clearing zones (decolorization zones) were found. The results showed that under anaerobic condition RB-5 molecules were reduced and aromatic amines were generated. The aromatic amine metabolite was partly removed in subsequent aerobic bio-treatment. It was possible to achieve more than 90% decolorization and approximately 46% reduction in amine metabolite concentration through two-stage anaerobic-aerobic treatment after a reaction period of 2 days.

  4. Modern approaches of monitoring children's physical state in the process of physical education

    Directory of Open Access Journals (Sweden)

    Kashuba V.A.

    2010-01-01

    Full Text Available The questions of the use of the systems of estimation of bodily condition are considered in an educational process on physical education. Certain and grounded informing indexes of bodily condition of children of midchildhood. Indexes are fixed in basis of the checking system. The questions of possibility of the use of modern information technologies are exposed in an educational process on physical education. System of control of bodily condition is offered. The checking system is characterized moduleness. It is based on integral approach.

  5. The Design, Construction and Operation of a 75 kW Two-Stage Gasifier

    DEFF Research Database (Denmark)

    Henriksen, Ulrik Birk; Ahrenfeldt, Jesper; Jensen, Torben Kvist

    2003-01-01

    The Two-Stage Gasifier was operated for several weeks (465 hours) and of these 190 hours continuously. The gasifier is operated automatically unattended day and night, and only small adjustments of the feeding rate were necessary once or twice a day. The operation was successful, and the output a...... of the reactor had to be constructed in some other material....

  6. Two-Stage MAS Technique for Analysis of DRA Elements and Arrays on Finite Ground Planes

    DEFF Research Database (Denmark)

    Larsen, Niels Vesterdal; Breinbjerg, Olav

    2007-01-01

    A two-stage Method of Auxiliary Sources (MAS) technique is proposed for analysis of dielectric resonator antenna (DRA) elements and arrays on finite ground planes (FGPs). The problem is solved by first analysing the DRA on an infinite ground plane (IGP) and then using this solution to model the FGP...... problem....

  7. Use a Log Splitter to Demonstrate Two-Stage Hydraulic Pump

    Science.gov (United States)

    Dell, Timothy W.

    2012-01-01

    The two-stage hydraulic pump is commonly used in many high school and college courses to demonstrate hydraulic systems. Unfortunately, many textbooks do not provide a good explanation of how the technology works. Another challenge that instructors run into with teaching hydraulic systems is the cost of procuring an expensive real-world machine…

  8. Two-Stage Sampling Procedures for Comparing Means When Population Distributions Are Non-Normal.

    Science.gov (United States)

    Luh, Wei-Ming; Olejnik, Stephen

    Two-stage sampling procedures for comparing two population means when variances are heterogeneous have been developed by D. G. Chapman (1950) and B. K. Ghosh (1975). Both procedures assume sampling from populations that are normally distributed. The present study reports on the effect that sampling from non-normal distributions has on Type I error…

  9. Some design aspects of a two-stage rail-to-rail CMOS op amp

    NARCIS (Netherlands)

    Gierkink, S.L.J.; Holzmann, Peter J.; Wiegerink, R.J.; Wassenaar, R.F.

    1999-01-01

    A two-stage low-voltage CMOS op amp with rail-to-rail input and output voltage ranges is presented. The circuit uses complementary differential input pairs to achieve the rail-to-rail common-mode input voltage range. The differential pairs operate in strong inversion, and the constant transconductan

  10. Kinetics analysis of two-stage austenitization in supermartensitic stainless steel

    DEFF Research Database (Denmark)

    Nießen, Frank; Villa, Matteo; Hald, John

    2017-01-01

    The martensite-to-austenite transformation in X4CrNiMo16-5-1 supermartensitic stainless steel was followed in-situ during isochronal heating at 2, 6 and 18 K min−1 applying energy-dispersive synchrotron X-ray diffraction at the BESSY II facility. Austenitization occurred in two stages, separated...

  11. An intracooling system for a novel two-stage sliding-vane air compressor

    Science.gov (United States)

    Murgia, Stefano; Valenti, Gianluca; Costanzo, Ida; Colletta, Daniele; Contaldi, Giulio

    2017-08-01

    Lube-oil injection is used in positive-displacement compressors and, among them, in sliding-vane machines to guarantee the correct lubrication of the moving parts and as sealing to prevent air leakage. Furthermore, lube-oil injection allows to exploit lubricant also as thermal ballast with a great thermal capacity to minimize the temperature increase during the compression. This study presents the design of a two-stage sliding-vane rotary compressor in which the air cooling is operated by high-pressure cold oil injection into a connection duct between the two stages. The heat exchange between the atomized oil jet and the air results in a decrease of the air temperature before the second stage, improving the overall system efficiency. This cooling system is named here intracooling, as opposed to intercooling. The oil injection is realized via pressure-swirl nozzles, both within the compressors and inside the intracooling duct. The design of the two-stage sliding-vane compressor is accomplished by way of a lumped parameter model. The model predicts an input power reduction as large as 10% for intercooled and intracooled two-stage compressors, the latter being slightly better, with respect to a conventional single-stage compressor for compressed air applications. An experimental campaign is conducted on a first prototype that comprises the low-pressure compressor and the intracooling duct, indicating that a significant temperature reduction is achieved in the duct.

  12. Development of a heavy-duty diesel engine with two-stage turbocharging

    NARCIS (Netherlands)

    Sturm, L.; Kruithof, J.

    2001-01-01

    A mean value model was developed by using Matrixx/ Systembuild simulation tool for designing real-time control algorithms for the two-stage engine. All desired characteristics are achieved, apart from lower A/F ratio at lower engine speeds and Turbocharger matches calculations. The CANbus is used to

  13. Two-stage estimation in copula models used in family studies

    DEFF Research Database (Denmark)

    Andersen, Elisabeth Anne Wreford

    2005-01-01

    In this paper register based family studies provide the motivation for studying a two-stage estimation procedure in copula models for multivariate failure time data. The asymptotic properties of the estimators in both parametric and semi-parametric models are derived, generalising the approach by...

  14. Extraoral implants for orbit rehabilitation: a comparison between one-stage and two-stage surgeries.

    Science.gov (United States)

    de Mello, M C L M P; Guedes, R; de Oliveira, J A P; Pecorari, V A; Abrahão, M; Dib, L L

    2014-03-01

    The aim of the study was to compare the osseointegration success rate and time for delivery of the prosthesis among cases treated by two-stage or one-stage surgery for orbit rehabilitation between 2003 and 2011. Forty-five patients were included, 31 males and 14 females; 22 patients had two-stage surgery and 23 patients had one-stage surgery. A total 138 implants were installed, 42 (30.4%) on previously irradiated bone. The implant survival rate was 96.4%, with a success rate of 99.0% among non-irradiated patients and 90.5% among irradiated patients. Two-stage patients received 74 implants with a survival rate of 94.6% (four implants lost); one-stage surgery patients received 64 implants with a survival rate of 98.4% (one implant lost). The median time interval between implant fixation and delivery of the prosthesis for the two-stage group was 9.6 months and for the one-stage group was 4.0 months (P < 0.001). The one-stage technique proved to be reliable and was associated with few risks and complications; the rate of successful osseointegration was similar to those reported in the literature. The one-stage technique should be considered a viable procedure that shortens the time to final rehabilitation and facilitates appropriate patient follow-up treatment.

  15. Validation of Continuous CHP Operation of a Two-Stage Biomass Gasifier

    DEFF Research Database (Denmark)

    Ahrenfeldt, Jesper; Henriksen, Ulrik Birk; Jensen, Torben Kvist

    2006-01-01

    The Viking gasification plant at the Technical University of Denmark was built to demonstrate a continuous combined heat and power operation of a two-stage gasifier fueled with wood chips. The nominal input of the gasifier is 75 kW thermal. To validate the continuous operation of the plant, a 9-d...

  16. High rate treatment of terephthalic acid production wastewater in a two-stage anaerobic bioreactor

    NARCIS (Netherlands)

    Kleerebezem, R.; Beckers, J.; Pol, L.W.H.; Lettinga, G.

    2005-01-01

    The feasibility was studied of anaerobic treatment of wastewater generated during purified terephthalic acid (PTA) production in two-stage upflow anaerobic sludge blanket (UASB) reactor system. The artificial influent of the system contained the main organic substrates of PTA-wastewater: acetate, be

  17. A Two-Stage Exercise on the Binomial Distribution Using Minitab.

    Science.gov (United States)

    Shibli, M. Abdullah

    1990-01-01

    Describes a two-stage experiment that was designed to explain binomial distribution to undergraduate statistics students. A manual coin flipping exercise is explained as the first stage; a computerized simulation using MINITAB software is presented as stage two; and output from the MINITAB exercises is included. (two references) (LRW)

  18. Two-stage laparoscopic resection of colon cancer and metastatic liver tumour

    Directory of Open Access Journals (Sweden)

    Yukio Iwashita

    2012-01-01

    Full Text Available We report herein the case of 70-year-old woman in whom colon cancer and a synchronous metastatic liver tumour were successfully resected laparoscopically. The tumours were treated in two stages. Both post-operative courses were uneventful, and there has been no recurrence during the 8 months since the second procedure.

  19. Two-stage laparoscopic resection of colon cancer and metastatic liver tumour

    Directory of Open Access Journals (Sweden)

    Iwashita Yukio

    2005-01-01

    Full Text Available We report herein the case of 70-year-old woman in whom colon cancer and a synchronous metastatic liver tumour were successfully resected laparoscopically. The tumours were treated in two stages. Both postoperative courses were uneventful, and there has been no recurrence during the 8 months since the second procedure.

  20. Two-stage bargaining with coverage extension in a dual labour market

    DEFF Research Database (Denmark)

    Roberts, Mark A.; Stæhr, Karsten; Tranæs, Torben

    2000-01-01

    This paper studies coverage extension in a simple general equilibrium model with a dual labour market. The union sector is characterized by two-stage bargaining whereas the firms set wages in the non-union sector. In this model firms and unions of the union sector have a commonality of interest...

  1. Designing quantum information processing via structural physical approximation

    Science.gov (United States)

    Bae, Joonwoo

    2017-10-01

    In quantum information processing it may be possible to have efficient computation and secure communication beyond the limitations of classical systems. In a fundamental point of view, however, evolution of quantum systems by the laws of quantum mechanics is more restrictive than classical systems, identified to a specific form of dynamics, that is, unitary transformations and, consequently, positive and completely positive maps to subsystems. This also characterizes classes of disallowed transformations on quantum systems, among which positive but not completely maps are of particular interest as they characterize entangled states, a general resource in quantum information processing. Structural physical approximation offers a systematic way of approximating those non-physical maps, positive but not completely positive maps, with quantum channels. Since it has been proposed as a method of detecting entangled states, it has stimulated fundamental problems on classifications of positive maps and the structure of Hermitian operators and quantum states, as well as on quantum measurement such as quantum design in quantum information theory. It has developed efficient and feasible methods of directly detecting entangled states in practice, for which proof-of-principle experimental demonstrations have also been performed with photonic qubit states. Here, we present a comprehensive review on quantum information processing with structural physical approximations and the related progress. The review mainly focuses on properties of structural physical approximations and their applications toward practical information applications.

  2. Multi-Scale Physical Process in the Magnetosphere

    Institute of Scientific and Technical Information of China (English)

    CAO Jinbin; LIU Zhenxing

    2008-01-01

    The brief report presents a part of the research results of the magnetospheric physics researches in China during the period of 2006--2008.During the past two years,China-ESA cooperation DSP(Double Star Program)satellites were basically operating normally in its extended lifetime.The DSP and Cluster missions provide Chinese space physicists high quality data to study multi-scale physical process in the magnetosphere.The work made based on the data of DSP is presented in the paper of"Progress of Double Star Program"of this issue.

  3. Relationship between snow microstructure and physical and chemical processes

    Directory of Open Access Journals (Sweden)

    T. Bartels-Rausch

    2012-11-01

    Full Text Available Ice and snow in the environment are important because they not only act as a host to rich chemistry but also provide a matrix for physical exchanges of contaminants within the ecosystem. This review discusses how the structure of snow influences both chemical reactivity and physical processes, which thereby makes snow a unique medium for study. The focus is placed on impacts of the presence of liquid and surface disorder using many experimental studies, simulations, and field observations from the molecular to the micro-scale.

  4. Contextualization processes and the initial education of physics teachers

    Directory of Open Access Journals (Sweden)

    Cristina Cândida de Macedo

    2014-03-01

    Full Text Available Contextualization of school contents has been seen as a possibility of facilitating students’ learning, since it makes the educative process more significant to them. However, there is no agreement as to the meaning and the forms of applying such processes. Particularly in the area of Science teaching, the creation of thematic projects has been seen as a way of contextualizing school contents. It is noteworthy that the experience with the education of Physics teachers shows that the creation and execution of such projects brings many difficulties to teachers, the main obstacle being the understanding of what contextualized educative processes are. Having this in mind, a project has been elaborated with the objective of analyzing the comprehension Physics teachers that are going through teacher education courses have of the processes of contextualization. The data for this investigation has been obtained from students who attended a course of the Physics Teacher Education module at the Federal University of Itajubá. It is significant to mention that in this course students are asked to create three versions of a thematic project. In order to analyze the data, the procedure of Thematic Content and Category Analysis was adopted. This research shows that Physics teachers to be incorporate the discourses of the educative ideas throughout the course. However, there is a series of obstacles they face as they attempt to understand and carry out contextualized educative processes. Those difficulties are connected to their experience with this kind of educative process throughout the years they spend at school and in the teacher education course. We conclude thus that it is essential that contextualized educative activities be part of the reality of teacher education programs.

  5. The Bracka two-stage repair for severe proximal hypospadias: A single center experience

    Directory of Open Access Journals (Sweden)

    Rakesh S Joshi

    2015-01-01

    Full Text Available Background: Surgical correction of severe proximal hypospadias represents a significant surgical challenge and single-stage corrections are often associated with complications and reoperations. Bracka two-stage repair is an attractive alternative surgical procedure with superior, reliable, and reproducible results. Purpose: To study the feasibility and applicability of Bracka two-stage repair for the severe proximal hypospadias and to analyze the outcomes and complications of this surgical technique. Materials and Methods: This prospective study was conducted from January 2011 to December 2013. Bracka two-stage repair was performed using inner preputial skin as a free graft in subjects with proximal hypospadias in whom severe degree of chordee and/or poor urethral plate was present. Only primary cases were included in this study. All subjects received three doses of intra-muscular testosterone 3 weeks apart before first stage. Second stage was performed 6 months after the first stage. Follow-up ranged from 6 months to 24 months. Results: A total of 43 patients operated for Bracka repair, out of which 30 patients completed two-stage repair. Mean age of the patients was 4 years and 8 months. We achieved 100% graft uptake and no revision was required. Three patients developed fistula, while two had metal stenosis. Glans dehiscence, urethral stricture and the residual chordee were not found during follow-up and satisfactory cosmetic results with good urinary stream were achieved in all cases. Conclusion: The Bracka two-stage repair is a safe and reliable approach in select patients in whom it is impractical to maintain the axial integrity of the urethral plate, and, therefore, a full circumference urethral reconstruction become necessary. This gives good results both in terms of restoration of normal function with minimal complication.

  6. Influence of one- or two-stage methods for polymerizing complete dentures on adaptation and teeth movements

    Directory of Open Access Journals (Sweden)

    Moises NOGUEIRA

    Full Text Available Abstract Introduction The quality of complete dentures might be influenced by the method of confection. Objective To evaluate the influence of two different methods of processing muco-supported complete dentures on their adaptation and teeth movements. Material and method Denture confection was assigned in two groups (n=10 for upper and lower arches according to polymerization method: 1 conventional one-stage - a wax trial base was made, teeth were arranged and polymerized; 2 two-stage method - the base was waxed and first polymerized. With the denture base polymerized, the teeth were arranged and then, performed the final polymerization. Teeth movements were evaluated in the distances between incisive (I-I, pre-molars (P-P, molars (M-M, left incisor to left molar (LI-LM and right incisor to right molar (RI-RM. For the adaptation analysis, dentures were cut in three different positions: (A distal face of canines, (B mesial face of the first molars, and (C distal face of second molars. Result Denture bases have shown a significant better adaptation when polymerized in the one-stage procedure for both the upper (p=0.000 and the lower (p=0.000 arches, with region A presenting significant better adaptation than region C. In the upper arch, significant reduction in the distance between I-I was observed in the one-stage technique, while the two-stage technique promoted significant reduction in the RI-RM distance. In the lower arch, one-stage technique promoted significant reduction in the distance for RI-RM and two-stage promoted significant reduction in the LI-LM distance. Conclusion Conventional one-stage method presented the better results for denture adaptation. Both fabrication methods presented some alteration in teeth movements.

  7. Two-stage high-rate biogas (H2 and CH4) production from food waste using anaerobic mixed microflora

    Science.gov (United States)

    Xu, K.; Lee, D.; Kobayashi, T.; Ebie, Y.; Li, Y.; Inamori, Y.

    2010-12-01

    To achieve the high-rate H2 and CH4 production from food waste using fermentative anaerobic microflora, the effects of carbonate-alkalinity in the recirculated digestion sludge on continuous two-stage fermentation were investigated. Higher H2 production rate of 2.9 L-H2/L/day was achieved at the recycle ratio of 1.0 in an alkalinity range of 9000 to 10000 mg-CaCO3/L. The maximum CH4 production rate was stably maintained at the range of 1.85 to 1.88 L-CH4/L/day without alkalinity change. Carbonate alkalinity in digestion sludge could reduce the H2 partial pressure in the headspace of the fermentation reactors, and improve a biogas production capacity in the two-stage fermentation process. The average volatile solids degradation rate in the overall process increased as the digestion sludge recycle increased from 0.5 to 1.0. These results show that the alkalinity in recycle of the digestion sludge is crucial factor in determining biogas (H2 and CH4) production capacity and reducing the total solids.

  8. Modelling of Two-Stage Anaerobic Treating Wastewater from a Molasses-Based Ethanol Distillery with the IWA Anaerobic Digestion Model No.1

    OpenAIRE

    Kittikhun Taruyanon; Sarun Tejasen

    2010-01-01

    This paper presents the application of ADM1 model to simulate the dynamic behaviour of a two-stage anaerobic treatment process treating the wastewater generated from the ethanol distillery process. The laboratory-scale process comprised an anaerobic continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket (UASB) connecting in series, was used to treat wastewater from the ethanol distillery process. The CSTR and UASB hydraulic retention times (HRT) were 12 and 70 hours, re...

  9. Physical activity across the curriculum: year one process evaluation results

    Directory of Open Access Journals (Sweden)

    Sullivan Debra K

    2008-07-01

    Full Text Available Abstract Background Physical Activity Across the Curriculum (PAAC is a 3-year elementary school-based intervention to determine if increased amounts of moderate intensity physical activity performed in the classroom will diminish gains in body mass index (BMI. It is a cluster-randomized, controlled trial, involving 4905 children (2505 intervention, 2400 control. Methods We collected both qualitative and quantitative process evaluation data from 24 schools (14 intervention and 10 control, which included tracking teacher training issues, challenges and barriers to effective implementation of PAAC lessons, initial and continual use of program specified activities, and potential competing factors, which might contaminate or lessen program effects. Results Overall teacher attendance at training sessions showed exceptional reach. Teachers incorporated active lessons on most days, resulting in significantly greater student physical activity levels compared to controls (p Conclusion In the first year of the PAAC intervention, process evaluation results were instrumental in identifying successes and challenges faced by teachers when trying to modify existing academic lessons to incorporate physical activity.

  10. The construction and use of bacterial DNA microarrays based on an optimized two-stage PCR strategy

    Directory of Open Access Journals (Sweden)

    Pesta David

    2003-06-01

    Full Text Available Abstract Background DNA microarrays are a powerful tool with important applications such as global gene expression profiling. Construction of bacterial DNA microarrays from genomic sequence data using a two-stage PCR amplification approach for the production of arrayed DNA is attractive because it allows, in principal, the continued re-amplification of DNA fragments and facilitates further utilization of the DNA fragments for additional uses (e.g. over-expression of protein. We describe the successful construction and use of DNA microarrays by the two-stage amplification approach and discuss the technical challenges that were met and resolved during the project. Results Chimeric primers that contained both gene-specific and shared, universal sequence allowed the two-stage amplification of the 3,168 genes identified on the genome of Synechocystis sp. PCC6803, an important prokaryotic model organism for the study of oxygenic photosynthesis. The gene-specific component of the primer was of variable length to maintain uniform annealing temperatures during the 1st round of PCR synthesis, and situated to preserve full-length ORFs. Genes were truncated at 2 kb for efficient amplification, so that about 92% of the PCR fragments were full-length genes. The two-stage amplification had the additional advantage of normalizing the yield of PCR products and this improved the uniformity of DNA features robotically deposited onto the microarray surface. We also describe the techniques utilized to optimize hybridization conditions and signal-to-noise ratio of the transcription profile. The inter-lab transportability was demonstrated by the virtual error-free amplification of the entire genome complement of 3,168 genes using the universal primers in partner labs. The printed slides have been successfully used to identify differentially expressed genes in response to a number of environmental conditions, including salt stress. Conclusions The technique detailed

  11. Geneva University: Experiments in Physics: Hands-on Creative Processes

    CERN Multimedia

    Université de Genève

    2011-01-01

    Geneva University Physics Department 24, quai Ernest-Ansermet CH-1211 Geneva 4 Tel: (022) 379 62 73 Fax: (022) 379 69 92   Lundi 3 octobre 2011, 17h00 Ecole de Physique, Auditoire Stueckelberg «Experiments in Physics : Hands-on Creative Processes» Prof. Manfred Euler Leibniz-Institute for Mathematics and Science Education (IPN) University of Kiel, Deutschland Experiments play a variety of different roles in knowledge generation. The lecture will focus on the function of experiments as engines of intuition that foster insights into complex processes. The experimental presentations consider self-organization phenomena in various domains that range from the nanomechanics of biomolecules to perception and cognition. The inherent universality contributes to elucidating the enigmatic phenomenon of creativity. Une verrée en compagnie du conférencier sera offerte après le colloque.       &...

  12. Coal conversion processes and their materials requirements. Physical sciences

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, J.B.; Voorde, M. van de; Betteridge, W.

    1984-01-01

    The coal conversion processes combustion, gasification and liquefaction are discussed with respect to current industrial developments and material problems in industrial plants due to fouling, corrosion and erosion. The available materials are discussed by means of high temperature corrosion, erosion, ductibility, creep, fatigue and physical properties. Ceramics and refractories which are particularly used as thermal insulation are also discussed by means of corrosion and erosion and mechanical properties.

  13. Influence of different natural physical fields on biological processes

    Science.gov (United States)

    Mashinsky, A. L.

    2001-01-01

    In space flight conditions gravity, magnetic, and electrical fields as well as ionizing radiation change both in size, and in direction. This causes disruptions in the conduct of some physical processes, chemical reactions, and metabolism in living organisms. In these conditions organisms of different phylogenetic level change their metabolic reactions undergo changes such as disturbances in ionic exchange both in lower and in higher plants, changes in cell morphology for example, gyrosity in Proteus ( Proteus vulgaris), spatial disorientation in coleoptiles of Wheat ( Triticum aestivum) and Pea ( Pisum sativum) seedlings, mutational changes in Crepis ( Crepis capillaris) and Arabidopsis ( Arabidopsis thaliana) seedling. It has been found that even in the absence of gravity, gravireceptors determining spatial orientation in higher plants under terrestrial conditions are formed in the course of ontogenesis. Under weightlessness this system does not function and spatial orientation is determined by the light flux gradient or by the action of some other factors. Peculiarities of the formation of the gravireceptor apparatus in higher plants, amphibians, fish, and birds under space flight conditions have been observed. It has been found that the system in which responses were accompanied by phase transition have proven to be gravity-sensitive under microgravity conditions. Such reactions include also the process of photosynthesis which is the main energy production process in plants. In view of the established effects of microgravity and different natural physical fields on biological processes, it has been shown that these processes change due to the absence of initially rigid determination. The established biological effect of physical fields influence on biological processes in organisms is the starting point for elucidating the role of gravity and evolutionary development of various organisms on Earth.

  14. An efficient and accurate two-stage fourth-order gas-kinetic scheme for the Euler and Navier-Stokes equations

    Science.gov (United States)

    Pan, Liang; Xu, Kun; Li, Qibing; Li, Jiequan

    2016-12-01

    provides a dynamic process of evolution from the kinetic scale particle free transport to the hydrodynamic scale wave propagation, which provides the physics for the non-equilibrium numerical shock structure construction to the near equilibrium NS solution. As a result, with the implementation of the fifth-order WENO initial reconstruction, in the smooth region the current two-stage GKS provides an accuracy of O ((Δx) 5 ,(Δt) 4) for the Euler equations, and O ((Δx) 5 ,τ2 Δt) for the NS equations, where τ is the time between particle collisions. Many numerical tests, including difficult ones for the Navier-Stokes solvers, have been used to validate the current method. Perfect numerical solutions can be obtained from the high Reynolds number boundary layer to the hypersonic viscous heat conducting flow. Following the two-stage time-stepping framework, the third-order GKS flux function can be used as well to construct a fifth-order method with the usage of both first-order and second-order time derivatives of the flux function. The use of time-accurate flux function may have great advantages on the development of higher-order CFD methods.

  15. Urgency of evolution-process congruent thinking in physics

    Science.gov (United States)

    Roychoudhuri, Chandrasekhar

    2015-09-01

    It is now generally recognized that physics has not been contributing anything conceptually fundamentally new beyond the century old Relativity and 90 years old Quantum Mechanics [1-4]. We have also started recognizing that there is an increasing rate of species extinction all over the world, especially since the last century [5]; and we are beginning to understand that the related problems are being steadily accelerated by human behavior to conquer nature, rather than understanding nature as is and living within its system logics [6,7]. We are beginning to appreciate that our long-term sustainability as a species literally depends upon proactively learning to nurture the entire bio-diversity [8-10]. Thus, humans must consciously become evolution process congruent thinkers. The evolutionary biologists have been crying out loud for us to listen [5,6, 8-10]. Social scientists, political scientists, economic scientists [13] have started chiming in to become consilient thinkers [6] for re-constructing sustainable societies. But, the path to consilient thinking requires us to recognize and accept a common vision based thinking process, which functionally serves as a uniting platform. I am articulating that platform as the "evolution process congruent thinking" (EPCT). Do physicists have any obligation to co-opt this EPCT? Is there any immediate and/or long-term gain for them? This paper argues affirmatively that co-opting EPCT is the best way to re-anchor physics back to reality ontology and develop newer and deeper understanding of natural phenomena based on understanding of the diverse interaction processes going on in nature. Physics is mature enough to acknowledge that all of our theories are "work in progress". This is a good time to start iteratively re-evaluating and re-structuring all the foundational postulates behind all the working theories. This will also consistently energize all the follow-on generation of physicists to keep on fully utilizing their

  16. Process depending morphology and resulting physical properties of TPU

    Energy Technology Data Exchange (ETDEWEB)

    Frick, Achim, E-mail: achim.frick@hs-aalen.de; Spadaro, Marcel, E-mail: marcel.spadaro@hs-aalen.de [Institute of Polymer Science and Processing (iPSP), Aalen University (Germany)

    2015-12-17

    Thermoplastic polyurethane (TPU) is a rubber like material with outstanding properties, e.g. for seal applications. TPU basically provides high strength, low frictional behavior and excellent wear resistance. Though, due to segmented structure of TPU, which is composed of hard segments (HSs) and soft segments (SSs), physical properties depend strongly on the morphological arrangement of the phase separated HSs at a certain ratio of HSs to SSs. It is obvious that the TPU deforms differently depending on its bulk morphology. Basically, the morphology can either consist of HSs segregated into small domains, which are well dispersed in the SS matrix or of few strongly phase separated large size HS domains embedded in the SS matrix. The morphology development is hardly ruled by the melt processing conditions of the TPU. Depending on the morphology, TPU provides quite different physical properties with respect to strength, deformation behavior, thermal stability, creep resistance and tribological performance. The paper deals with the influence of important melt processing parameters, such as temperature, pressure and shear conditions, on the resulting physical properties tested by tensile and relaxation experiments. Furthermore the morphology is studied employing differential scanning calorimeter (DSC), transmission light microscopy (TLM), scanning electron beam microscopy (SEM) and transmission electron beam microscopy (TEM) investigations. Correlations between processing conditions and resulting TPU material properties are elaborated. Flow and shear simulations contribute to the understanding of thermal and flow induced morphology development.

  17. Quantum Processes and Dynamic Networks in Physical and Biological Systems.

    Science.gov (United States)

    Dudziak, Martin Joseph

    Quantum theory since its earliest formulations in the Copenhagen Interpretation has been difficult to integrate with general relativity and with classical Newtonian physics. There has been traditionally a regard for quantum phenomena as being a limiting case for a natural order that is fundamentally classical except for microscopic extrema where quantum mechanics must be applied, more as a mathematical reconciliation rather than as a description and explanation. Macroscopic sciences including the study of biological neural networks, cellular energy transports and the broad field of non-linear and chaotic systems point to a quantum dimension extending across all scales of measurement and encompassing all of Nature as a fundamentally quantum universe. Theory and observation lead to a number of hypotheses all of which point to dynamic, evolving networks of fundamental or elementary processes as the underlying logico-physical structure (manifestation) in Nature and a strongly quantized dimension to macroscalar processes such as are found in biological, ecological and social systems. The fundamental thesis advanced and presented herein is that quantum phenomena may be the direct consequence of a universe built not from objects and substance but from interacting, interdependent processes collectively operating as sets and networks, giving rise to systems that on microcosmic or macroscopic scales function wholistically and organically, exhibiting non-locality and other non -classical phenomena. The argument is made that such effects as non-locality are not aberrations or departures from the norm but ordinary consequences of the process-network dynamics of Nature. Quantum processes are taken to be the fundamental action-events within Nature; rather than being the exception quantum theory is the rule. The argument is also presented that the study of quantum physics could benefit from the study of selective higher-scale complex systems, such as neural processes in the brain

  18. Physical Processes in Strong Magnetic Fields of Neutron Stars

    CERN Document Server

    Harding, A K

    2003-01-01

    Neutron stars have inferred surface magnetic fields of up to 10^{14} Gauss, in the case of radio pulsars, and up to possibly 10^{15} Gauss, in the case of Soft Gamma-Ray Repeaters and Anomalous X-ray Pulsars. In fields this high, QED effects will profoundly change the characteristics of continuum radiation processes such as synchrotron emission and Compton scattering and will also allow the possibility of additional physical processes such as one-photon pair production, vacuum polarization and photon splitting. Atomic line processes will also be significantly affected by the presence of strong fields. I will review some of the properties of radiation processes in strong magnetic fields that are most relevant to pulsars, SGRs and AXPs and the role they play in models for these sources.

  19. Matching tutor to student: rules and mechanisms for efficient two-stage learning in neural circuits

    CERN Document Server

    Tesileanu, Tiberiu; Balasubramanian, Vijay

    2016-01-01

    Existing models of birdsong learning assume that brain area LMAN introduces variability into song for trial-and-error learning. Recent data suggest that LMAN also encodes a corrective bias driving short-term improvements in song. These later consolidate in area RA, a motor cortex analogue downstream of LMAN. We develop a new model of such two-stage learning. Using a stochastic gradient descent approach, we derive how 'tutor' circuits should match plasticity mechanisms in 'student' circuits for efficient learning. We further describe a reinforcement learning framework with which the tutor can build its teaching signal. We show that mismatching the tutor signal and plasticity mechanism can impair or abolish learning. Applied to birdsong, our results predict the temporal structure of the corrective bias from LMAN given a plasticity rule in RA. Our framework can be applied predictively to other paired brain areas showing two-stage learning.

  20. S-band gain-flattened EDFA with two-stage double-pass configuration

    Science.gov (United States)

    Fu, Hai-Wei; Xu, Shi-Chao; Qiao, Xue-Guang; Jia, Zhen-An; Liu, Ying-Gang; Zhou, Hong

    2011-11-01

    A gain-flattened S-band erbium-doped fiber amplifier (EDFA) using standard erbium-doped fiber (EDF) is proposed and experimentally demonstrated. The proposed amplifier with two-stage double-pass configuration employs two C-band suppressing filters to obtain the optical gain in S-band. The amplifier provides a maximum signal gain of 41.6 dB at 1524 nm with the corresponding noise figure of 3.8 dB. Furthermore, with a well-designed short-pass filter as a gain flattening filter (GFF), we are able to develop the S-band EDFA with a flattened gain of more than 20 dB in 1504-1524 nm. In the experiment, the two-stage double-pass amplifier configuration improves performance of gain and noise figure compared with the configuration of single-stage double-pass S-band EDFA.

  1. Power Frequency Oscillation Suppression Using Two-Stage Optimized Fuzzy Logic Controller for Multigeneration System

    Directory of Open Access Journals (Sweden)

    Y. K. Bhateshvar

    2016-01-01

    Full Text Available This paper attempts to develop a linearized model of automatic generation control (AGC for an interconnected two-area reheat type thermal power system in deregulated environment. A comparison between genetic algorithm optimized PID controller (GA-PID, particle swarm optimized PID controller (PSO-PID, and proposed two-stage based PSO optimized fuzzy logic controller (TSO-FLC is presented. The proposed fuzzy based controller is optimized at two stages: one is rule base optimization and other is scaling factor and gain factor optimization. This shows the best dynamic response following a step load change with different cases of bilateral contracts in deregulated environment. In addition, performance of proposed TSO-FLC is also examined for ±30% changes in system parameters with different type of contractual demands between control areas and compared with GA-PID and PSO-PID. MATLAB/Simulink® is used for all simulations.

  2. A two-stage scheme for multi-view human pose estimation

    Science.gov (United States)

    Yan, Junchi; Sun, Bing; Liu, Yuncai

    2010-08-01

    We present a two-stage scheme integrating voxel reconstruction and human motion tacking. By combining voxel reconstruction with human motion tracking interactively, our method can work in a cluttered background where perfect foreground silhouettes are hardly available. For each frame, a silhouette-based 3D volume reconstruction method and hierarchical tracking algorithm are applied in two stages. In the first stage, coarse reconstruction and tracking results are obtained, and then the refinement for reconstruction is applied in the second stage. The experimental results demonstrate our approach is promising. Although our method focuses on the problem of human body voxel reconstruction and motion tracking in this paper, our scheme can be used to reconstruct voxel data and infer the pose of many specified rigid and articulated objects.

  3. Toward Improving Electrocardiogram (ECG) Biometric Verification using Mobile Sensors: A Two-Stage Classifier Approach.

    Science.gov (United States)

    Tan, Robin; Perkowski, Marek

    2017-02-20

    Electrocardiogram (ECG) signals sensed from mobile devices pertain the potential for biometric identity recognition applicable in remote access control systems where enhanced data security is demanding. In this study, we propose a new algorithm that consists of a two-stage classifier combining random forest and wavelet distance measure through a probabilistic threshold schema, to improve the effectiveness and robustness of a biometric recognition system using ECG data acquired from a biosensor integrated into mobile devices. The proposed algorithm is evaluated using a mixed dataset from 184 subjects under different health conditions. The proposed two-stage classifier achieves a total of 99.52% subject verification accuracy, better than the 98.33% accuracy from random forest alone and 96.31% accuracy from wavelet distance measure algorithm alone. These results demonstrate the superiority of the proposed algorithm for biometric identification, hence supporting its practicality in areas such as cloud data security, cyber-security or remote healthcare systems.

  4. Effect of two-stage aging on superplasticity of Al-Li alloy

    Institute of Scientific and Technical Information of China (English)

    LUO Zhi-hui; ZHANG Xin-ming; DU Yu-xuan; YE Ling-ying

    2006-01-01

    The effect of two-stage aging on the microstructures and superplasticity of 01420 Al-Li alloy was investigated by means of OM, TEM analysis and stretching experiment. The results demonstrate that the second phase particles distributed more uniformly with a larger volume fraction can be observed after the two-stage aging (120 ℃, 12 h+300 ℃, 36 h) compared with the single-aging(300 ℃, 48 h). After rolling and recrystallization annealing, fine grains with size of 8-10 μm are obtained, and the superplastic elongation of the specimens reaches 560% at strain rate of 8×10-4 s-1 and 480 ℃. Uniformly distributed fine particles precipitate both on grain boundaries and in grains at lower temperature. When the sheet is aged at high temperature, the particles become coarser with a large volume fraction.

  5. Performance measurement of insurance firms using a two-stage DEA method

    Directory of Open Access Journals (Sweden)

    Raha Jalili Sabet

    2013-01-01

    Full Text Available Measuring the relative performance of insurance firms plays an important role in this industry. In this paper, we present a two-stage data envelopment analysis to measure the performance of insurance firms, which were active over the period of 2006-2010. The proposed study of this paper performs DEA method in two stages where the first stage considers five inputs and three outputs while the second stage considers the outputs of the first stage as the inputs of the second stage and uses three different outputs for this stage. The results of our survey have indicated that while there were 4 efficient insurance firms most other insurances were noticeably inefficient. This means market was monopolized mostly by a limited number of insurance firms and competition was not fare enough to let other firms participate in economy, more efficiently.

  6. Direct Torque Control of Sensorless Induction Machine Drives: A Two-Stage Kalman Filter Approach

    Directory of Open Access Journals (Sweden)

    Jinliang Zhang

    2015-01-01

    Full Text Available Extended Kalman filter (EKF has been widely applied for sensorless direct torque control (DTC in induction machines (IMs. One key problem associated with EKF is that the estimator suffers from computational burden and numerical problems resulting from high order mathematical models. To reduce the computational cost, a two-stage extended Kalman filter (TEKF based solution is presented for closed-loop stator flux, speed, and torque estimation of IM to achieve sensorless DTC-SVM operations in this paper. The novel observer can be similarly derived as the optimal two-stage Kalman filter (TKF which has been proposed by several researchers. Compared to a straightforward implementation of a conventional EKF, the TEKF estimator can reduce the number of arithmetic operations. Simulation and experimental results verify the performance of the proposed TEKF estimator for DTC of IMs.

  7. Syme's two-stage amputation in insulin-requiring diabetics with gangrene of the forefoot.

    Science.gov (United States)

    Pinzur, M S; Morrison, C; Sage, R; Stuck, R; Osterman, H; Vrbos, L

    1991-06-01

    Thirty-five insulin-requiring adult diabetic patients underwent 38 Syme's Two-Stage amputations for gangrene of the forefoot with nonreconstructible peripheral vascular insufficiency. All had a minimum Doppler ischemic index of 0.5, serum albumin of 3.0 gm/dl, and total lymphocyte count of 1500. Thirty-one (81.6%) eventually healed and were uneventfully fit with a prosthesis. Regional anesthesia was used in all of the patients, with 22 spinal and 16 ankle block anesthetics. Twenty-seven (71%) returned to their preamputation level of ambulatory function. Six (16%) had major, and fifteen (39%) minor complications following the first stage surgery. The results of this study support the use of the Syme's Two-Stage amputation in adult diabetic patients with gangrene of the forefoot requiring amputation.

  8. Low-noise SQUIDs with large transfer: two-stage SQUIDs based on DROSs

    Science.gov (United States)

    Podt, M.; Flokstra, J.; Rogalla, H.

    2002-08-01

    We have realized a two-stage integrated superconducting quantum interference device (SQUID) system with a closed loop bandwidth of 2.5 MHz, operated in a direct voltage readout mode. The corresponding flux slew rate was 1.3×10 5Φ0/s and the measured white flux noise was 1.3 μ Φ0/√Hz at 4.2 K. The system is based on a conventional dc SQUID with a double relaxation oscillation SQUID (DROS) as the second stage. Because of the large flux-to-voltage transfer, the sensitivity of the system is completely determined by the sensor SQUID and not by the DROS or the room-temperature preamplifier. Decreasing the Josephson junction area enables a further improvement of the sensitivity of the two-stage SQUID systems.

  9. Interval estimation of binomial proportion in clinical trials with a two-stage design.

    Science.gov (United States)

    Tsai, Wei-Yann; Chi, Yunchan; Chen, Chia-Min

    2008-01-15

    Generally, a two-stage design is employed in Phase II clinical trials to avoid giving patients an ineffective drug. If the number of patients with significant improvement, which is a binomial response, is greater than a pre-specified value at the first stage, then another binomial response at the second stage is also observed. This paper considers interval estimation of the response probability when the second stage is allowed to continue. Two asymptotic interval estimators, Wald and score, as well as two exact interval estimators, Clopper-Pearson and Sterne, are constructed according to the two binomial responses from this two-stage design, where the binomial response at the first stage follows a truncated binomial distribution. The mean actual coverage probability and expected interval width are employed to evaluate the performance of these interval estimators. According to the comparison results, the score interval is recommended for both Simon's optimal and minimax designs.

  10. Experiment and surge analysis of centrifugal two-stage turbocharging system

    Institute of Scientific and Technical Information of China (English)

    Yituan HE; Chaochen MA

    2008-01-01

    To study a centrifugal two-stage turbocharging system's surge and influencing factors, a special test bench was set up and the system surge test was performed. The test results indicate that the measured parameters such as air mass flow and rotation speed of a high pressure (HP) stage compressor can be converted into corrected para-meters under a standard condition according to the Mach number similarity criterion, because the air flow in a HP stage compressor has entered the Reynolds number (Re) auto-modeling range. Accordingly, the reasons leading to a two-stage turbocharging system's surge can be analyzed according to the corrected mass flow characteristic maps and actual operating conditions of HP and low pressure (LP) stage compressors.

  11. A New Soil Infiltration Technology for Decentralized Sewage Treatment: Two-Stage Anaerobic Tank and Soil Trench System

    Institute of Scientific and Technical Information of China (English)

    YE Chun; HU Zhan-Bo; KONG Hai-Nan; WANG Xin-Ze; HE Sheng-Bing

    2008-01-01

    The low removal efficiency of total nitrogen (TN) is one of the main disadvantages of traditional single stage subsurface infiltration system,which combines an anaerobic tank and a soil filter field.In this study,a full-scale,two-stage anaerobic tank and soil trench system was designed and operated to evaluate the feasibility and performances in treating sewage from a school campus for over a one-year monitoring period.The raw sewage was prepared and fed into the first anaerobic tank and second tank by 60% and 40%,respectively.This novel process could decrease chemical oxygen demand with the dichromate method by 89%-96%,suspended solids by 91%-97%,and total phosphorus by 91%-97%.The denitrification was satisfactory in the second stage soil trench,so the removals of TN as well as ammonia nitrogen (NH+4-N) reached 68%-75% and 96%-99%,respectively.It appeared that the removal efficiency of TN in this two-stage anaerobic tank and soil trench system was more effective than that in the single stage soil infiltration system.The effluent met the discharge standard for the sewage treatment plant (GB18918-2002) of China.

  12. A Mathematical Programming Model for Tactical Planning with Set-up Continuity in a Two-stage Ceramic Firm

    Directory of Open Access Journals (Sweden)

    David Pérez Perales

    2016-07-01

    Full Text Available It is known that capacity issues in tactical production plans in a hierarchical context are relevant since its inaccurate determination may lead to unrealistic or simply non-feasible plans at the operational level. Semi-continuous industrial processes, such as ceramic ones, often imply large setups and their consideration is crucial for accurate capacity estimation. However, in most of production planning models developed in a hierarchical context at this tactical (aggregated level, setup changes are not explicitly considered. Their consideration includes not only decisions about lot sizing of production, but also allocation, known as Capacitated Lot Sizing and Loading Problem (CLSLP. However, CLSLP does not account for set-up continuity, specially important in contexts with lengthy and costly set-ups and where product families minimum run length are similar to planning periods. In this work, a mixed integer linear programming (MILP model for a two stage ceramic firm which accounts for lot sizing and loading decisions including minimum lot-sizes and set-up continuity between two consecutive periods is proposed. Set-up continuity inclusion is modelled just considering which product families are produced at the beginning and at the end of each period of time, and not the complete sequence. The model is solved over a simplified two-stage real-case within a Spanish ceramic firm. Obtained results confirm its validity.

  13. Two-staged management for all types of congenital pouch colon

    Directory of Open Access Journals (Sweden)

    Rajendra K Ghritlaharey

    2013-01-01

    Full Text Available Background: The aim of this study was to review our experience with two-staged management for all types of congenital pouch colon (CPC. Patients and Methods: This retrospective study included CPC cases that were managed with two-staged procedures in the Department of Paediatric Surgery, over a period of 12 years from 1 January 2000 to 31 December 2011. Results: CPC comprised of 13.71% (97 of 707 of all anorectal malformations (ARM and 28.19% (97 of 344 of high ARM. Eleven CPC cases (all males were managed with two-staged procedures. Distribution of cases (Narsimha Rao et al.′s classification into types I, II, III, and IV were 1, 2, 6, and 2, respectively. Initial operative procedures performed were window colostomy (n = 6, colostomy proximal to pouch (n = 4, and ligation of colovesical fistula and end colostomy (n = 1. As definitive procedures, pouch excision with abdomino-perineal pull through (APPT of colon in eight, and pouch excision with APPT of ileum in three were performed. The mean age at the time of definitive procedures was 15.6 months (ranges from 3 to 53 months and the mean weight was 7.5 kg (ranges from 4 to 11 kg. Good fecal continence was observed in six and fair in two cases in follow-up periods, while three of our cases lost to follow up. There was no mortality following definitive procedures amongst above 11 cases. Conclusions: Two-staged procedures for all types of CPC can also be performed safely with good results. The most important fact that the definitive procedure is being done without protective stoma and therefore, it avoids stoma closure, stoma-related complications, related cost of stoma closure and hospital stay.

  14. Hybrid staging of a Lysholm positive displacement engine with two Westinghouse two stage impulse Curtis turbines

    Energy Technology Data Exchange (ETDEWEB)

    Parker, D.A.

    1982-06-01

    The University of California at Berkeley has tested and modeled satisfactorly a hybrid staged Lysholm engine (positive displacement) with a two stage Curtis wheel turbine. The system operates in a stable manner over its operating range (0/1-3/1 water ratio, 120 psia input). Proposals are made for controlling interstage pressure with a partial admission turbine and volume expansion to control mass flow and pressure ratio for the Lysholm engine.

  15. Full noise characterization of a low-noise two-stage SQUID amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Falferi, P [Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, 38100 Povo, Trento (Italy); Mezzena, R [INFN, Gruppo Collegato di Trento, Sezione di Padova, 38100 Povo, Trento (Italy); Vinante, A [INFN, Sezione di Padova, 35131 Padova (Italy)], E-mail: falferi@science.unitn.it

    2009-07-15

    From measurements performed on a low-noise two-stage SQUID amplifier coupled to a high- Q electrical resonator we give a complete noise characterization of the SQUID amplifier around the resonator frequency of 11 kHz in terms of additive, back action and cross-correlation noise spectral densities. The minimum noise temperature evaluated at 135 mK is 10 {mu}K and corresponds to an energy resolution of 18{Dirac_h}.

  16. A covariate adjusted two-stage allocation design for binary responses in randomized clinical trials.

    Science.gov (United States)

    Bandyopadhyay, Uttam; Biswas, Atanu; Bhattacharya, Rahul

    2007-10-30

    In the present work, we develop a two-stage allocation rule for binary response using the log-odds ratio within the Bayesian framework allowing the current allocation to depend on the covariate value of the current subject. We study, both numerically and theoretically, several exact and limiting properties of this design. The applicability of the proposed methodology is illustrated by using some data set. We compare this rule with some of the existing rules by computing various performance measures.

  17. Investigation on a two-stage solvay refrigerator with magnetic material regenerator

    Science.gov (United States)

    Chen, Guobang; Zheng, Jianyao; Zhang, Fagao; Yu, Jianping; Tao, Zhenshi; Ding, Cenyu; Zhang, Liang; Wu, Peiyi; Long, Yi

    This paper describes experimental results that the no-load temperature of a two-stage Solvay refrigerator has been reached in liquid helium temperature region from the original 11.5 K by using magnetic regenerative material instead of lead. The structure and technological characteristics of the prototype machine are presented. The effects of operating frequency and pressure on the refrigerating temperature have been discussed in this paper.

  18. The two-stage aegean extension, from localized to distributed, a result of slab rollback acceleration

    OpenAIRE

    Brun, Jean-Pierre; Faccenna, Claudio; Gueydan, Frédéric; Sokoutis, Dimitrios; Philippon, Mélody; Kydonakis, Konstantinos; Gorini, Christian

    2016-01-01

    International audience; Back-arc extension in the Aegean, which was driven by slab rollback since 45 Ma, is described here for the first time in two stages. From Middle Eocene to Middle Miocene, deformation was localized leading to i) the exhumation of high-pressure metamorphic rocks to crustal depths, ii) the exhumation of high-temperature metamorphic rocks in core complexes and iii) the deposition of sedimentary basins. Since Middle Miocene, extension distributed over the whole Aegean domai...

  19. A Two-stage Discriminating Framework for Making Supply Chain Operation Decisions under Uncertainties

    OpenAIRE

    Gu, H; Rong, G

    2010-01-01

    This paper addresses the problem of making supply chain operation decisions for refineries under two types of uncertainties: demand uncertainty and incomplete information shared with suppliers and transport companies. Most of the literature only focus on one uncertainty or treat more uncertainties identically. However, we note that refineries have more power to control uncertainties in procurement and transportation than in demand in the real world. Thus, a two-stage framework for dealing wit...

  20. Low-noise SQUIDs with large transfer: two-stage SQUIDs based on DROSs

    NARCIS (Netherlands)

    Podt, M.; Flokstra, Jakob; Rogalla, Horst

    2002-01-01

    We have realized a two-stage integrated superconducting quantum interference device (SQUID) system with a closed loop bandwidth of 2.5 MHz, operated in a direct voltage readout mode. The corresponding flux slew rate was 1.3×105 Φ0/s and the measured white flux noise was 1.3 μΦ0/√Hz at 4.2 K. The

  1. Latent Inhibition as a Function of US Intensity in a Two-Stage CER Procedure

    Science.gov (United States)

    Rodriguez, Gabriel; Alonso, Gumersinda

    2004-01-01

    An experiment is reported in which the effect of unconditioned stimulus (US) intensity on latent inhibition (LI) was examined, using a two-stage conditioned emotional response (CER) procedure in rats. A tone was used as the pre-exposed and conditioned stimulus (CS), and a foot-shock of either a low (0.3 mA) or high (0.7 mA) intensity was used as…

  2. Two stage dual gate MESFET monolithic gain control amplifier for Ka-band

    Science.gov (United States)

    Sokolov, V.; Geddes, J.; Contolatis, A.

    A monolithic two stage gain control amplifier has been developed using submicron gate length dual gate MESFETs fabricated on ion implanted material. The amplifier has a gain of 12 dB at 30 GHz with a gain control range of over 30 dB. This ion implanted monolithic IC is readily integrable with other phased array receiver functions such as low noise amplifiers and phase shifters.

  3. Exergy analysis of vapor compression refrigeration cycle with two-stage and intercooler

    Science.gov (United States)

    Kılıç, Bayram

    2012-07-01

    In this study, exergy analyses of vapor compression refrigeration cycle with two-stage and intercooler using refrigerants R507, R407c, R404a were carried out. The necessary thermodynamic values for analyses were calculated by Solkane program. The coefficient of performance, exergetic efficiency and total irreversibility rate of the system in the different operating conditions for these refrigerants were investigated. The coefficient of performance, exergetic efficiency and total irreversibility rate for alternative refrigerants were compared.

  4. Exergy analysis of vapor compression refrigeration cycle with two-stage and intercooler

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, Bayram [Mehmet Akif Ersoy University, Bucak Emin Guelmez Vocational School, Bucak, Burdur (Turkey)

    2012-07-15

    In this study, exergy analyses of vapor compression refrigeration cycle with two-stage and intercooler using refrigerants R507, R407c, R404a were carried out. The necessary thermodynamic values for analyses were calculated by Solkane program. The coefficient of performance, exergetic efficiency and total irreversibility rate of the system in the different operating conditions for these refrigerants were investigated. The coefficient of performance, exergetic efficiency and total irreversibility rate for alternative refrigerants were compared. (orig.)

  5. Performance of Combined Water Turbine Darrieus-Savonius with Two Stage Savonius Buckets and Single Deflector

    OpenAIRE

    Sahim, Kaprawi; Santoso, Dyos; Sipahutar, Riman

    2016-01-01

    The objective of this study is to show the effect of single deflector plate on the performance of combined Darrieus-Savonius water turbine. In order to overcome the disadvantages of low torque of solo Darrieus turbine, a plate deflector mounted in front of returning Savonius bucket of combined water turbine composing of Darrieus and Savonius rotor has been proposed in this study. Some configurations of combined turbines with two stage Savonius rotors were experimentally tested in a river of c...

  6. Perceived Health Benefits and Soy Consumption Behavior: Two-Stage Decision Model Approach

    OpenAIRE

    Moon, Wanki; Balasubramanian, Siva K.; Rimal, Arbindra

    2005-01-01

    A two-stage decision model is developed to assess the effect of perceived soy health benefits on consumers' decisions with respect to soy food. The first stage captures whether or not to consume soy food, while the second stage reflects how often to consume. A conceptual/analytical framework is also employed, combining Lancaster's characteristics model and Fishbein's multi-attribute model. Results show that perceived soy health benefits significantly influence both decision stages. Further, c...

  7. High quantum efficiency mid-wavelength interband cascade infrared photodetectors with one and two stages

    Science.gov (United States)

    Zhou, Yi; Chen, Jianxin; Xu, Zhicheng; He, Li

    2016-08-01

    In this paper, we report on mid-wavelength infrared interband cascade photodetectors grown on InAs substrates. We studied the transport properties of the photon-generated carriers in the interband cascade structures by comparing two different detectors, a single stage detector and a two-stage cascade detector. The two-stage device showed quantum efficiency around 19.8% at room temperature, and clear optical response was measured even at a temperature of 323 K. The two detectors showed similar Johnson-noise limited detectivity. The peak detectivity of the one- and two-stage devices was measured to be 2.15 × 1014 cm·Hz1/02/W and 2.19 × 1014 cm·Hz1/02/W at 80 K, 1.21 × 109 cm·Hz1/02/W and 1.23 × 109 cm·Hz1/02/W at 300 K, respectively. The 300 K background limited infrared performance (BLIP) operation temperature is estimated to be over 140 K.

  8. Development of Two-Stage Stirling Cooler for ASTRO-F

    Science.gov (United States)

    Narasaki, K.; Tsunematsu, S.; Ootsuka, K.; Kyoya, M.; Matsumoto, T.; Murakami, H.; Nakagawa, T.

    2004-06-01

    A two-stage small Stirling cooler has been developed and tested for the infrared astronomical satellite ASTRO-F that is planned to be launched by Japanese M-V rocket in 2005. ASTRO-F has a hybrid cryogenic system that is a combination of superfluid liquid helium (HeII) and two-stage Stirling coolers. The mechanical cooler has a two-stage displacer driven by a linear motor in a cold head and a new linear-ball-bearing system for the piston-supporting structure in a compressor. The linear-ball-bearing supporting system achieves the piston clearance seal, the long piston-stroke operation and the low frequency operation. The typical cooling power is 200 mW at 20 K and the total input power to the compressor and the cold head is below 90 W without driver electronics. The engineering, the prototype and the flight models of the cooler have been fabricated and evaluated to verify the capability for ASTRO-F. This paper describes the design of the cooler and the results from verification tests including cooler performance test, thermal vacuum test, vibration test and lifetime test.

  9. A two-stage Stirling-type pulse tube cryocooler with a cold inertance tube

    Science.gov (United States)

    Gan, Z. H.; Fan, B. Y.; Wu, Y. Z.; Qiu, L. M.; Zhang, X. J.; Chen, G. B.

    2010-06-01

    A thermally coupled two-stage Stirling-type pulse tube cryocooler (PTC) with inertance tubes as phase shifters has been designed, manufactured and tested. In order to obtain a larger phase shift at the low acoustic power of about 2.0 W, a cold inertance tube as well as a cold reservoir for the second stage, precooled by the cold end of the first stage, was introduced into the system. The transmission line model was used to calculate the phase shift produced by the cold inertance tube. Effect of regenerator material, geometry and charging pressure on the performance of the second stage of the two-stage PTC was investigated based on the well known regenerator model REGEN. Experimental results of the two-stage PTC were carried out with an emphasis on the performance of the second stage. A lowest cooling temperature of 23.7 K and 0.50 W at 33.9 K were obtained with an input electric power of 150.0 W and an operating frequency of 40 Hz.

  10. Rehabilitation outcomes in patients with early and two-stage reconstruction of flexor tendon injuries.

    Science.gov (United States)

    Sade, Ilgin; İnanir, Murat; Şen, Suzan; Çakmak, Esra; Kablanoğlu, Serkan; Selçuk, Barin; Dursun, Nigar

    2016-08-01

    [Purpose] The primary aim of this study was to assess rehabilitation outcomes for early and two-stage repair of hand flexor tendon injuries. The secondary purpose of this study was to compare the findings between treatment groups. [Subjects and Methods] Twenty-three patients were included in this study. Early repair (n=14) and two-stage repair (n=9) groups were included in a rehabilitation program that used hand splints. This retrospective evaluated patients according to their demographic characteristics, including age, gender, injured hand, dominant hand, cause of injury, zone of injury, number of affected fingers, and accompanying injuries. Pain, range of motion, and grip strength were evaluated using a visual analog scale, goniometer, and dynamometer, respectively. [Results] Both groups showed significant improvements in pain and finger flexion after treatment compared with baseline measurements. However, no significant differences were observed between the two treatment groups. Similar results were obtained for grip strength and pinch grip, whereas gross grip was better in the early tendon repair group. [Conclusion] Early and two-stage reconstruction of patients with flexor tendon injuries can be performed with similarly favorable responses and effective rehabilitation programs.

  11. A Comparison of Direct and Two-Stage Transportation of Patients to Hospital in Poland

    Directory of Open Access Journals (Sweden)

    Anna Rosiek

    2015-04-01

    Full Text Available Background: The rapid international expansion of telemedicine reflects the growth of technological innovations. This technological advancement is transforming the way in which patients can receive health care. Materials and Methods: The study was conducted in Poland, at the Department of Cardiology of the Regional Hospital of Louis Rydygier in Torun. The researchers analyzed the delay in the treatment of patients with acute coronary syndrome. The study was conducted as a survey and examined 67 consecutively admitted patients treated invasively in a two-stage transport system. Data were analyzed statistically. Results: Two-stage transportation does not meet the timeframe guidelines for the treatment of patients with acute myocardial infarction. Intervals for the analyzed group of patients were statistically significant (p < 0.0001. Conclusions: Direct transportation of the patient to a reference center with interventional cardiology laboratory has a significant impact on reducing in-hospital delay in case of patients with acute coronary syndrome. Perspectives: This article presents the results of two-stage transportation of the patient with acute coronary syndrome. This measure could help clinicians who seek to assess time needed for intervention. It also shows how time from the beginning of pain in chest is important and may contribute to patient disability, death or well-being.

  12. Two-Stage Liver Transplantation with Temporary Porto-Middle Hepatic Vein Shunt

    Directory of Open Access Journals (Sweden)

    Giovanni Varotti

    2010-01-01

    Full Text Available Two-stage liver transplantation (LT has been reported for cases of fulminant liver failure that can lead to toxic hepatic syndrome, or massive hemorrhages resulting in uncontrollable bleeding. Technically, the first stage of the procedure consists of a total hepatectomy with preservation of the recipient's inferior vena cava (IVC, followed by the creation of a temporary end-to-side porto-caval shunt (TPCS. The second stage consists of removing the TPCS and implanting a liver graft when one becomes available. We report a case of a two-stage total hepatectomy and LT in which a temporary end-to-end anastomosis between the portal vein and the middle hepatic vein (TPMHV was performed as an alternative to the classic end-to-end TPCS. The creation of a TPMHV proved technically feasible and showed some advantages compared to the standard TPCS. In cases in which a two-stage LT with side-to-side caval reconstruction is utilized, TPMHV can be considered as a safe and effective alternative to standard TPCS.

  13. Two-stage residual inclusion estimation: addressing endogeneity in health econometric modeling.

    Science.gov (United States)

    Terza, Joseph V; Basu, Anirban; Rathouz, Paul J

    2008-05-01

    The paper focuses on two estimation methods that have been widely used to address endogeneity in empirical research in health economics and health services research-two-stage predictor substitution (2SPS) and two-stage residual inclusion (2SRI). 2SPS is the rote extension (to nonlinear models) of the popular linear two-stage least squares estimator. The 2SRI estimator is similar except that in the second-stage regression, the endogenous variables are not replaced by first-stage predictors. Instead, first-stage residuals are included as additional regressors. In a generic parametric framework, we show that 2SRI is consistent and 2SPS is not. Results from a simulation study and an illustrative example also recommend against 2SPS and favor 2SRI. Our findings are important given that there are many prominent examples of the application of inconsistent 2SPS in the recent literature. This study can be used as a guide by future researchers in health economics who are confronted with endogeneity in their empirical work.

  14. Two-stage solar concentrators based on parabolic troughs: asymmetric versus symmetric designs.

    Science.gov (United States)

    Schmitz, Max; Cooper, Thomas; Ambrosetti, Gianluca; Steinfeld, Aldo

    2015-11-20

    While nonimaging concentrators can approach the thermodynamic limit of concentration, they generally suffer from poor compactness when designed for small acceptance angles, e.g., to capture direct solar irradiation. Symmetric two-stage systems utilizing an image-forming primary parabolic concentrator in tandem with a nonimaging secondary concentrator partially overcome this compactness problem, but their achievable concentration ratio is ultimately limited by the central obstruction caused by the secondary. Significant improvements can be realized by two-stage systems having asymmetric cross-sections, particularly for 2D line-focus trough designs. We therefore present a detailed analysis of two-stage line-focus asymmetric concentrators for flat receiver geometries and compare them to their symmetric counterparts. Exemplary designs are examined in terms of the key optical performance metrics, namely, geometric concentration ratio, acceptance angle, concentration-acceptance product, aspect ratio, active area fraction, and average number of reflections. Notably, we show that asymmetric designs can achieve significantly higher overall concentrations and are always more compact than symmetric systems designed for the same concentration ratio. Using this analysis as a basis, we develop novel asymmetric designs, including two-wing and nested configurations, which surpass the optical performance of two-mirror aplanats and are comparable with the best reported 2D simultaneous multiple surface designs for both hollow and dielectric-filled secondaries.

  15. Study on two stage activated carbon/HFC-134a based adsorption chiller

    Science.gov (United States)

    >K Habib,

    2013-06-01

    In this paper, a theoretical analysis on the performance of a thermally driven two-stage four-bed adsorption chiller utilizing low-grade waste heat of temperatures between 50°C and 70°C in combination with a heat sink (cooling water) of 30°C for air-conditioning applications has been described. Activated carbon (AC) of type Maxsorb III/HFC-134a pair has been examined as an adsorbent/refrigerant pair. FORTRAN simulation program is developed to analyze the influence of operating conditions (hot and cooling water temperatures and adsorption/desorption cycle times) on the cycle performance in terms of cooling capacity and COP. The main advantage of this two-stage chiller is that it can be operational with smaller regenerating temperature lifts than other heat-driven single-stage chillers. Simulation results shows that the two-stage chiller can be operated effectively with heat sources of 50°C and 70°C in combination with a coolant at 30°C.

  16. A Two-stage injection-locked magnetron for accelerators with superconducting cavities

    CERN Document Server

    Kazakevich, Grigory; Flanagan, Gene; Marhauser, Frank; Neubauer, Mike; Yakovlev, Vyacheslav; Chase, Brian; Nagaitsev, Sergey; Pasquinelli, Ralph; Solyak, Nikolay; Tupikov, Vitali; Wolff, Daniel

    2013-01-01

    A concept for a two-stage injection-locked CW magnetron intended to drive Superconducting Cavities (SC) for intensity-frontier accelerators has been proposed. The concept considers two magnetrons in which the output power differs by 15-20 dB and the lower power magnetron being frequency-locked from an external source locks the higher power magnetron. The injection-locked two-stage CW magnetron can be used as an RF power source for Fermilab's Project-X to feed separately each of the 1.3 GHz SC of the 8 GeV pulsed linac. We expect output/locking power ratio of about 30-40 dB assuming operation in a pulsed mode with pulse duration of ~ 8 ms and repetition rate of 10 Hz. The experimental setup of a two-stage magnetron utilising CW, S-band, 1 kW tubes operating at pulse duration of 1-10 ms, and the obtained results are presented and discussed in this paper.

  17. Study on the Control Algorithm of Two-Stage DC-DC Converter for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Changhao Piao

    2014-01-01

    Full Text Available The fast response, high efficiency, and good reliability are very important characteristics to electric vehicles (EVs dc/dc converters. Two-stage dc-dc converter is a kind of dc-dc topologies that can offer those characteristics to EVs. Presently, nonlinear control is an active area of research in the field of the control algorithm of dc-dc converters. However, very few papers research on two-stage converter for EVs. In this paper, a fixed switching frequency sliding mode (FSFSM controller and double-integral sliding mode (DISM controller for two-stage dc-dc converter are proposed. And a conventional linear control (lag is chosen as the comparison. The performances of the proposed FSFSM controller are compared with those obtained by the lag controller. In consequence, the satisfactory simulation and experiment results show that the FSFSM controller is capable of offering good large-signal operations with fast dynamical responses to the converter. At last, some other simulation results are presented to prove that the DISM controller is a promising method for the converter to eliminate the steady-state error.

  18. Automotic Recognition of Sleep Spindles Based on Two-Stage Classifier with Artificial Neural Networks and Support Vector Machines

    Directory of Open Access Journals (Sweden)

    MohammadHoseyn Khaksar

    2008-03-01

    Full Text Available Sleep spindles are one of the most important transient waveforms found in the sleep EEG signal. Here, we introduce a two-stage procedure based on artificial neural networks for the automatic recognition of sleep spindles (SS in a 19-channel electroencephalographic signal. In the first stage, a pre-processing perception is used for enhancing overall detection and also reducing computation time. In the second stage, the selected Sleep spindles (SS, classified with neural network post-classifier. Classifying tools in post-processing procedure were MLP and RBSVM that their operations are compared in the last section of the report. Visual inspection of 19-channel EEG from six subjects by one expert in this theme, showed that RBSVM operation is better than MLP with BP (Back propagation training, that SVM provided 91.4% average sensitivity and 3.85% average false detection rate.

  19. Performance Evaluation of Two Node Tandem Communication Network with Dynamic Bandwidth Allocation having Two Stage Direct Bulk Arrivals

    Directory of Open Access Journals (Sweden)

    K. Srinivasa Rao

    2011-01-01

    Full Text Available A two node tandem communication network with dynamic bandwidth allocation (DBA having two stage direct bulk arrivals is developed and analyzed. The messages arriving to the source are packetized and stored in the buffers for forward transmission. Dynamic bandwidth allocation strategy is proposed by adjusting the transmission rate at every node just before transmission of each packet. The arrival and transmission processes at each node are characterized through compound Poisson and Poisson processes such that several of the statistical characteristics of communication networks identically matches. Using the difference - differential equations, the performance measures like the joint probability generating function of the content of two buffers, average buffer content, mean delays and throughput of nodes are derived and analyzed. It is observed that the bulk arrivals at two nodes and DBA have significant influence on performance measures. This network is much useful in Tele and Satellite communications.

  20. Two-stage crossed beam cooling with ⁶Li and ¹³³Cs atoms in microgravity.

    Science.gov (United States)

    Luan, Tian; Yao, Hepeng; Wang, Lu; Li, Chen; Yang, Shifeng; Chen, Xuzong; Ma, Zhaoyuan

    2015-05-04

    Applying the direct simulation Monte Carlo (DSMC) method developed for ultracold Bose-Fermi mixture gases research, we study the sympathetic cooling process of 6Li and 133Cs atoms in a crossed optical dipole trap. The obstacles to producing 6Li Fermi degenerate gas via direct sympathetic cooling with 133Cs are also analyzed, by which we find that the side-effect of the gravity is one of the main obstacles. Based on the dynamic nature of 6Li and 133Cs atoms, we suggest a two-stage cooling process with two pairs of crossed beams in microgravity environment. According to our simulations, the temperature of 6Li atoms can be cooled to T = 29.5 pK and T/TF = 0.59 with several thousand atoms, which propose a novel way to get ultracold fermion atoms with quantum degeneracy near pico-Kelvin.

  1. Two-stage acceleration of interstellar ions due to the interaction of high-energy lepton plasma flow

    CERN Document Server

    Cui, Yun-Qian; Lu, Quan-Ming; Li, Yu-Tong; Zhang, Jie

    2015-01-01

    We present the particle-in-cell (PIC) simulation results of the interaction of a high-energy lepton plasma flow with background electron-proton plasma and focus on the acceleration processes of the protons. It is found that the acceleration follows a two-stage processes. In the first stage, protons are accelerated transversely (perpendicular to the lepton flow) by the turbulent magnetic field "islands" generated via the strong Weibel-type instabilities. The accelerated protons shows a perfect inverse-power energy spectrum. As the interaction continues, a shockwave structure forms and the protons in front of the shockwave are reflected at twice of the shock speed, resulting in a quasi-monoenergetic peak located near 200MeV under the simulation parameters.

  2. Holistic simulation of geotechnical installation processes numerical and physical modelling

    CERN Document Server

    2015-01-01

    The book provides suitable methods for the simulations of boundary value problems of geotechnical installation processes with reliable prediction for the deformation behavior of structures in static or dynamic interaction with the soil. It summarizes the basic research of a research group from scientists dealing with constitutive relations of soils and their implementations as well as contact element formulations in FE-codes. Numerical and physical experiments are presented providing benchmarks for future developments in this field. Boundary value problems have been formulated and solved with the developed tools in order to show the effectivity of the methods. Parametric studies of geotechnical installation processes in order to identify the governing parameters for the optimization of the process are given in such a way that the findings can be recommended to practice for further use. For many design engineers in practice the assessment of the serviceability of nearby structures due to geotechnical installat...

  3. Physics Colloquium: The optical route to quantum information processing

    CERN Multimedia

    Université de Genève

    2011-01-01

    Geneva University Physics Department 24, Quai Ernest Ansermet CH-1211 Geneva 4 Monday 11 April 2011 17h00 - Ecole de Physique, Auditoire Stückelberg The optical route to quantum information processing Prof. Terry Rudolph/Imperial College, London Photons are attractive as carriers of quantum information both because they travel, and can thus transmit information, but also because of their good coherence properties and ease in undergoing single-qubit manipulations. The main obstacle to their use in information processing is inducing an effective interaction between them in order to produce entanglement. The most promising approach in photon-based information processing architectures is so-called measurement-based quantum computing. This relies on creating upfront a multi-qubit highly entangled state (the cluster state) which has the remarkable property that, once prepared, it can be used to perform quantum computation by making only single qubit measurements. In this talk I will discuss generically the...

  4. Determining the thermal and physicals properties of oil processing products

    Directory of Open Access Journals (Sweden)

    Viktoria I. Kryvda

    2015-03-01

    Full Text Available In the last decades both technological process’ improvement and primary energy resources saving are the main tasks of oil refineries. Using various oil products does impose an accurate knowledge of their properties. The dispersion analysis applied makes possible to construct a model simulating the primary oil refining products’ and raw materials’ thermal physical properties. As a result of data approximation there were obtained polynomials with coefficients differing from attributable to the studied oil products fractions. The research represents graphic dependences of thermal physical properties on temperature values for diesel oil fraction. The linear character of density and calorific capacity dependencies from temperature is represented with a proportional error in calculations. The relative minimum error is below 2% that confirms the implemented calculations’ adequacy. The resulting model can be used in calculations for further technological process improvements.

  5. Physical processes in the growth of the continental crust

    Science.gov (United States)

    Schubert, G.

    1988-01-01

    Major mechanisms of crustal addition are volcanism and plutonism at plate boundaries and within plate interiors. One approach to deciding if island arc magmatism dominated ancient crustal growth is to assess the rate at which the process has operated in the recent past. The localized addition rates were found to be comparable to present day global rates. One physical observable that was used to constrain models of crustal growth is sea level. A simple physical model was developed to explore the consequences of constant freeboard (the height of the continents above sea level). Global geoid and sea floor topography data were used to identify and study oceanic plateaus and swells that have either continental crustal roots or anomalously thick ocean crusts.

  6. Modelling of Two-Stage Anaerobic Treating Wastewater from a Molasses-Based Ethanol Distillery with the IWA Anaerobic Digestion Model No.1

    Directory of Open Access Journals (Sweden)

    Kittikhun Taruyanon

    2010-03-01

    Full Text Available This paper presents the application of ADM1 model to simulate the dynamic behaviour of a two-stage anaerobic treatment process treating the wastewater generated from the ethanol distillery process. The laboratory-scale process comprised an anaerobic continuous stirred tank reactor (CSTR and an upflow anaerobic sludge blanket (UASB connecting in series, was used to treat wastewater from the ethanol distillery process. The CSTR and UASB hydraulic retention times (HRT were 12 and 70 hours, respectively. The model was developed based on ADM1 basic structure and implemented with the simulation software AQUASIM. The simulated results were compared with measured data obtained from using the laboratory-scale two-stage anaerobic treatment process to treat wastewater. The sensitivity analysis identified maximum specific uptake rate (km and half-saturation constant (Ks of acetate degrader and sulfate reducing bacteria as the kinetic parameters which highly affected the process behaviour, which were further estimated. The study concluded that the model could predict the dynamic behaviour of a two-stage anaerobic treatment process treating the ethanol distillery process wastewater with varying strength of influents with reasonable accuracy.

  7. The physics of spreading processes in multilayer networks

    Science.gov (United States)

    de Domenico, Manlio; Granell, Clara; Porter, Mason A.; Arenas, Alex

    2016-10-01

    Despite the success of traditional network analysis, standard networks provide a limited representation of complex systems, which often include different types of relationships (or `multiplexity’) between their components. Such structural complexity has a significant effect on both dynamics and function. Throwing away or aggregating available structural information can generate misleading results and be a major obstacle towards attempts to understand complex systems. The recent multilayer approach for modelling networked systems explicitly allows the incorporation of multiplexity and other features of realistic systems. It allows one to couple different structural relationships by encoding them in a convenient mathematical object. It also allows one to couple different dynamical processes on top of such interconnected structures. The resulting framework plays a crucial role in helping to achieve a thorough, accurate understanding of complex systems. The study of multilayer networks has also revealed new physical phenomena that remain hidden when using ordinary graphs, the traditional network representation. Here we survey progress towards attaining a deeper understanding of spreading processes on multilayer networks, and we highlight some of the physical phenomena related to spreading processes that emerge from multilayer structure.

  8. Multiple heavy metals extraction and recovery from hazardous electroplating sludge waste via ultrasonically enhanced two-stage acid leaching.

    Science.gov (United States)

    Li, Chuncheng; Xie, Fengchun; Ma, Yang; Cai, Tingting; Li, Haiying; Huang, Zhiyuan; Yuan, Gaoqing

    2010-06-15

    An ultrasonically enhanced two-stage acid leaching process on extracting and recovering multiple heavy metals from actual electroplating sludge was studied in lab tests. It provided an effective technique for separation of valuable metals (Cu, Ni and Zn) from less valuable metals (Fe and Cr) in electroplating sludge. The efficiency of the process had been measured with the leaching efficiencies and recovery rates of the metals. Enhanced by ultrasonic power, the first-stage acid leaching demonstrated leaching rates of 96.72%, 97.77%, 98.00%, 53.03%, and 0.44% for Cu, Ni, Zn, Cr, and Fe respectively, effectively separated half of Cr and almost all of Fe from mixed metals. The subsequent second-stage leaching achieved leaching rates of 75.03%, 81.05%, 81.39%, 1.02%, and 0% for Cu, Ni, Zn, Cr, and Fe that further separated Cu, Ni, and Zn from mixed metals. With the stabilized two-stage ultrasonically enhanced leaching, the resulting over all recovery rates of Cu, Ni, Zn, Cr and Fe from electroplating sludge could be achieved at 97.42%, 98.46%, 98.63%, 98.32% and 100% respectively, with Cr and Fe in solids and the rest of the metals in an aqueous solution discharged from the leaching system. The process performance parameters studied were pH, ultrasonic power, and contact time. The results were also confirmed in an industrial pilot-scale test, and same high metal recoveries were performed.

  9. Two stage leaching of activated spent HDS catalyst and solvent extraction of aluminium using organo-phosphinic extractant, Cyanex 272.

    Science.gov (United States)

    Park, Kyung Ho; Mohapatra, Debasish; Nam, Chul-Woo

    2007-09-05

    Spent catalyst generally contains valuable metals like Mo, Co, Ni on a supporting material, such as gamma-A1(2)O(3). In the present study, a two stage alkali/acid leaching process is proposed to selectively target molybdenum and cobalt/nickel separately to facilitate the downstream processing. Prior to the leaching, the spent catalyst was calcined at 500 degrees C to remove C and S; and to convert metal sulphides to metal oxides. 98% Mo, 93% Co and 90% Ni was effectively recovered by this process. The sulphuric acid leaching of spent catalyst, previously treated by alkali solutions to remove Mo, yielded a solution rich in Ni, Co and Al. In order to recover Co and Ni, the Al impurity must be eliminated. The extraction and stripping of Al has been carried out using the organo-phosphinic extractant, Cyanex 272 diluted in carbon tetrachloride. Quantitative Al extraction efficiency was achieved with 1.0M Cyanex 272 in two stages at an aqueous:organic (A:O) phase ratio of 1:1 and equilibrium pH of 3.2. Complete stripping of Al from the loaded organic was carried out using 2M H(2)SO(4) at an A:O phase ratio of 1:1. The extraction reaction proceeded via the cation exchange mechanism and the extracted species was assumed to be AlA(3).3HA. The extraction of Al was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. The regenerated solvent was successfully used for 8 cycles without any significant loss of extraction efficiency, suggesting that Cyanex 272 is extremely stable under present experimental conditions.

  10. Physics of Stochastic Processes How Randomness Acts in Time

    CERN Document Server

    Mahnke, Reinhard; Lubashevsky, Ihor

    2008-01-01

    Based on lectures given by one of the authors with many years of experience in teaching stochastic processes, this textbook is unique in combining basic mathematical and physical theory with numerous simple and sophisticated examples as well as detailed calculations. In addition, applications from different fields are included so as to strengthen the background learned in the first part of the book. With its exercises at the end of each chapter (and solutions only available to lecturers) this book will benefit students and researchers at different educational levels. Solutions manual available

  11. Influence of wheat kernel physical properties on the pulverizing process.

    Science.gov (United States)

    Dziki, Dariusz; Cacak-Pietrzak, Grażyna; Miś, Antoni; Jończyk, Krzysztof; Gawlik-Dziki, Urszula

    2014-10-01

    The physical properties of wheat kernel were determined and related to pulverizing performance by correlation analysis. Nineteen samples of wheat cultivars about similar level of protein content (11.2-12.8 % w.b.) and obtained from organic farming system were used for analysis. The kernel (moisture content 10 % w.b.) was pulverized by using the laboratory hammer mill equipped with round holes 1.0 mm screen. The specific grinding energy ranged from 120 kJkg(-1) to 159 kJkg(-1). On the basis of data obtained many of significant correlations (p kernel physical properties and pulverizing process of wheat kernel, especially wheat kernel hardness index (obtained on the basis of Single Kernel Characterization System) and vitreousness significantly and positively correlated with the grinding energy indices and the mass fraction of coarse particles (> 0.5 mm). Among the kernel mechanical properties determined on the basis of uniaxial compression test only the rapture force was correlated with the impact grinding results. The results showed also positive and significant relationships between kernel ash content and grinding energy requirements. On the basis of wheat physical properties the multiple linear regression was proposed for predicting the average particle size of pulverized kernel.

  12. A STUDY OF NUCLEAR PHYSICS PROCESSES AT MIDDLE SCHOOL

    Directory of Open Access Journals (Sweden)

    Mykola I. Sadovyi

    2011-02-01

    Full Text Available The article discloses the problem of new technology usage for the physics’ experiment in the quantum physics modeling. Currency of investigation consists in the need of physics experiment organization and realization in high energy physics with the consistent usage of activity method in middle education institutions. This kind of method considerably stirs up the process of model usage and modeling, abstracting, idealization and analogy. Idealized objects’ creation, elementary part transmutation, in particular, that does not exist in the objective reality, but possesses definite prototypes in the real world that help in their first approximation to the truth. The program Macromedia Flesh has been used in the article. This program has a range of advantages comparing to other possible software according to their possibilities and usage simplicity. The program uses all kinds of computer graph (raster, vectorial, which gives great opportunities for graphic objects’ creation, and prepared files take minimum of the constant memory. A part of developed experiments of the modeling character is given in the article. Demonstrations are done in dynamic rate.

  13. Two-stage digestion of renewable raw materials. Applying bioleaching for utilizing grass silage; Zweiphasige Vergaerung nachwachsender Rohstoffe. Einsatz des Bioleaching-Verfahrens zur Verwertung von Grassilage

    Energy Technology Data Exchange (ETDEWEB)

    Zielonka, S.; Lemmer, A.; Oechsner, H. [Hohenheim Univ., Stuttgart (Germany). Landesanstalt fuer Landwirtschaftliches Maschinen- und Bauwesen; Jungbluth, T. [Hohenheim Univ., Stuttgart (Germany). Inst. fuer Agrartechnik

    2007-07-01

    Currently renewable raw materials are being used in full scale biogas plants as co-substrates. Using grass silage frequently caused technical problems till now. Within the framework of this project, a process to digest grass silage as a single substrate is being developed. An intermittently operating two-stage process is used. As far as the degree of degradation and methane yields are concerned, good and promising results have been achieved. (orig.)

  14. Economically efficient operation of two-stage fluidized-bed combustion systems; Wirtschaftliche Betriebsweise von zweistufigen Wirbelschicht-Verbrennungsanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E. [Hoelter-ABT GmbH, Essen (Germany)

    1996-11-01

    Two-stage stationary fluidized-bed combustion is an efficient technology for thermal treatment of residues. This includes, e.g. sorted residues from industrial processes, materials soiled with coatings, varnishes or glues, biomass (wood, straw, hay) and packaging materials. A simple and robust design of the plant with few mobile parts ensures high availability, good performance, and low investment and operation cost. The modular structure contributes to this. (orig.) [Deutsch] Mit der gestuften stationaeren Wirbelschichtverbrennung stellt eine Technologie zur thermischen Verwertung von Reststoffen fuer vielfaeltige Einsatzbereiche zur Verfuegung. Dazu zaehlten zum Beispiel sortenreine Reststoffe aus der Industrieproduktion, durch Beschichtungen, Anstriche oder Klebstoffe verunreinigte Materialien, Biomassen (Holz, Stroh, Heu) und Verpackungsmittelrueckstaende. Ein einfacher und robuster Anlagenaufbau mit wenigen beweglichen Teilen gewaehrleistet eine hohe Betriebssicherheit sowie die Anlagenverfuegbarkeit und verringert gleichzeitig die Investitions- und Betriebskosten. Hierzu traegt auch der Aufbau aus verschiedenen, immer gleichartigen Funktionsmodulen bei. (orig.)

  15. Two-stage epitaxial growth of vertically-aligned SnO2 nano-rods on (001) ceria

    Energy Technology Data Exchange (ETDEWEB)

    Solovyov, VF; Wu, LJ; Rupich, MW; Sathyamurthy, S; Li, XP; Li, Q

    2014-12-15

    Growth of high-aspect ratio oriented tin oxide, SnO2, nano-rods is complicated by a limited choice of matching substrates. We show that a (001) cerium oxide, CeO2, surface uniquely enables epitaxial growth of tin-oxide nano-rods via a two-stage process. First, (100) oriented nano-wires coat the ceria surface by lateral growth, forming a uniaxially-textured SnO2 deposit. Second, vertical SnO2 nano-rods nucleate on the deposit by homoepitaxy. We demonstrate growth of vertically oriented 1-2 mu m long nano-rods with an average diameter of approximate to 20 nm. 2014 Elsevier B.V. All rights reserved.

  16. The Construction of Cold-Chain Logistics Park of Agricultural Products in Sanshui from Two-stage Perspective

    Institute of Scientific and Technical Information of China (English)

    Jianhui; HUANG; Wei; WANG; Quan; LI

    2015-01-01

    This paper firstly analyzed the operation model,market positioning,market demand forecast as well as market competition and challenges,park site selection,and transportation conditions for construction of the Cold-Chain Logistics Park of Agricultural Products in Sanshui.Then,it presented the overall planning scheme for construction of the Cold-Chain Logistics Park of Agricultural Products from a progressive two-stage perspective of overall planning and stage-by-stage implementation.The first stage mainly performs the function as a transaction platform of agricultural products and meanwhile provides customers with agricultural products storage and inspection services.The second stage adds value-added services such as distribution processing,modified atmosphere storage,freezing and refrigeration,market price information distribution,E-commerce of agricultural products and personalized services.It is expected to provide references and suggestions for the construction of the Cold-Chain Logistics Park of Agricultural Products.

  17. Solar physics applications of computer graphics and image processing

    Science.gov (United States)

    Altschuler, M. D.

    1985-01-01

    Computer graphics devices coupled with computers and carefully developed software provide new opportunities to achieve insight into the geometry and time evolution of scalar, vector, and tensor fields and to extract more information quickly and cheaply from the same image data. Two or more different fields which overlay in space can be calculated from the data (and the physics), then displayed from any perspective, and compared visually. The maximum regions of one field can be compared with the gradients of another. Time changing fields can also be compared. Images can be added, subtracted, transformed, noise filtered, frequency filtered, contrast enhanced, color coded, enlarged, compressed, parameterized, and histogrammed, in whole or section by section. Today it is possible to process multiple digital images to reveal spatial and temporal correlations and cross correlations. Data from different observatories taken at different times can be processed, interpolated, and transformed to a common coordinate system.

  18. Solar physics applications of computer graphics and image processing

    Science.gov (United States)

    Altschuler, M. D.

    1985-01-01

    Computer graphics devices coupled with computers and carefully developed software provide new opportunities to achieve insight into the geometry and time evolution of scalar, vector, and tensor fields and to extract more information quickly and cheaply from the same image data. Two or more different fields which overlay in space can be calculated from the data (and the physics), then displayed from any perspective, and compared visually. The maximum regions of one field can be compared with the gradients of another. Time changing fields can also be compared. Images can be added, subtracted, transformed, noise filtered, frequency filtered, contrast enhanced, color coded, enlarged, compressed, parameterized, and histogrammed, in whole or section by section. Today it is possible to process multiple digital images to reveal spatial and temporal correlations and cross correlations. Data from different observatories taken at different times can be processed, interpolated, and transformed to a common coordinate system.

  19. Physics students' approaches to learning and cognitive processes in solving physics problems

    Science.gov (United States)

    Bouchard, Josee

    This study examined traditional instruction and problem-based learning (PBL) approaches to teaching and the extent to which they foster the development of desirable cognitive processes, including metacognition, critical thinking, physical intuition, and problem solving among undergraduate physics students. The study also examined students' approaches to learning and their perceived role as physics students. The research took place in the context of advanced courses of electromagnetism at a Canadian research university. The cognitive science, expertise, physics and science education, instructional psychology, and discourse processes literature provided the framework and background to conceptualize and structure this study. A within-stage mixed-model design was used and a number of instruments, including a survey, observation grids, and problem sets were developed specifically for this study. A special one-week long problem-based learning (PBL) intervention was also designed. Interviews with the instructors participating in the study provided complementary data. Findings include evidence that students in general engage in metacognitive processes in the organization of their personal study time. However, this potential, including the development of other cognitive processes, might not be stimulated as much as it could in the traditional lecture instructional context. The PBL approach was deemed as more empowering for the students. An unexpected finding came from the realisation that a simple exposure to a structured exercise of problem-solving (pre-test) was sufficient to produce superior planning and solving strategies on a second exposure (post-test) even for the students who had not been exposed to any special treatment. Maturation was ruled out as a potential threat to the validity of this finding. Another promising finding appears to be that the problem-based learning (PBL) intervention tends to foster the development of cognitive competencies, particularly

  20. Generalized Yule-walker and two-stage identification algorithms for dual-rate systems

    Institute of Scientific and Technical Information of China (English)

    Feng DING

    2006-01-01

    In this paper, two approaches are developed for directly identifying single-rate models of dual-rate stochastic systems in which the input updating frequency is an integer multiple of the output sampling frequency. The first is the generalized Yule-Walker algorithm and the second is a two-stage algorithm based on the correlation technique. The basic idea is to directly identify the parameters of underlying single-rate models instead of the lifted models of dual-rate systems from the dual-rate input-output data, assuming that the measurement data are stationary and ergodic. An example is given.

  1. Two-stage bargaining with coverage extension in a dual labour market

    DEFF Research Database (Denmark)

    Roberts, Mark A.; Stæhr, Karsten; Tranæs, Torben

    2000-01-01

    in extending coverage of a minimum wage to the non-union sector. Furthermore, the union sector does not seek to increase the non-union wage to a level above the market-clearing wage. In fact, it is optimal for the union sector to impose a market-clearing wage on the non-union sector. Finally, coverage......This paper studies coverage extension in a simple general equilibrium model with a dual labour market. The union sector is characterized by two-stage bargaining whereas the firms set wages in the non-union sector. In this model firms and unions of the union sector have a commonality of interest...

  2. SQL/JavaScript Hybrid Worms As Two-stage Quines

    CERN Document Server

    Orlicki, José I

    2009-01-01

    Delving into present trends and anticipating future malware trends, a hybrid, SQL on the server-side, JavaScript on the client-side, self-replicating worm based on two-stage quines was designed and implemented on an ad-hoc scenario instantiating a very common software pattern. The proof of concept code combines techniques seen in the wild, in the form of SQL injections leading to cross-site scripting JavaScript inclusion, and seen in the laboratory, in the form of SQL quines propa- gated via RFIDs, resulting in a hybrid code injection. General features of hybrid worms are also discussed.

  3. Two stage DOA and Fundamental Frequency Estimation based on Subspace Techniques

    DEFF Research Database (Denmark)

    Zhou, Zhenhua; Christensen, Mads Græsbøll; So, Hing-Cheung

    2012-01-01

    optimally weighted harmonic multiple signal classification (MCOW-HMUSIC) estimator is devised for the estimation of fundamental frequencies. Secondly, the spatio- temporal multiple signal classification (ST-MUSIC) estimator is proposed for the estimation of DOA with the estimated frequencies. Statistical......In this paper, the problem of fundamental frequency and direction-of-arrival (DOA) estimation for multi-channel harmonic sinusoidal signal is addressed. The estimation procedure consists of two stages. Firstly, by making use of the subspace technique and Markov-based eigenanalysis, a multi- channel...... evaluation with synthetic signals shows the high accuracy of the proposed methods compared with their non-weighting versions....

  4. Performance of the SITP 35K two-stage Stirling cryocooler

    Science.gov (United States)

    Liu, Dongyu; Li, Ao; Li, Shanshan; Wu, Yinong

    2010-04-01

    This paper presents the design, development, optimization experiment and performance of the SITP two-stage Stirling cryocooler. The geometry size of the cooler, especially the diameter and length of the regenerator were analyzed. Operating parameters by experiments were optimized to maximize the second stage cooling performance. In the test the cooler was operated at various drive frequency, phase shift between displacer and piston, fill pressure. The experimental results indicate that the cryocooler has a higher efficiency with a performance of 0.85W at 35K with a compressor input power of 56W at a phase shift of 65°, an operating frequency of 40Hz, 1MPa fill pressure.

  5. Two-Stage Bulk Electron Heating in the Diffusion Region of Anti-Parallel Symmetric Reconnection

    CERN Document Server

    Le, Ari; Daughton, William

    2016-01-01

    Electron bulk energization in the diffusion region during anti-parallel symmetric reconnection entails two stages. First, the inflowing electrons are adiabatically trapped and energized by an ambipolar parallel electric field. Next, the electrons gain energy from the reconnection electric field as they undergo meandering motion. These collisionless mechanisms have been decribed previously, and they lead to highly-structured electron velocity distributions. Nevertheless, a simplified control-volume analysis gives estimates for how the net effective heating scales with the upstream plasma conditions in agreement with fully kinetic simulations and spacecraft observations.

  6. Use of two-stage membrane countercurrent cascade for natural gas purification from carbon dioxide

    Science.gov (United States)

    Kurchatov, I. M.; Laguntsov, N. I.; Karaseva, M. D.

    2016-09-01

    Membrane technology scheme is offered and presented as a two-stage countercurrent recirculating cascade, in order to solve the problem of natural gas dehydration and purification from CO2. The first stage is a single divider, and the second stage is a recirculating two-module divider. This scheme allows natural gas to be cleaned from impurities, with any desired degree of methane extraction. In this paper, the optimal values of the basic parameters of the selected technological scheme are determined. An estimation of energy efficiency was carried out, taking into account the energy consumption of interstage compressor and methane losses in energy units.

  7. Forecasting long memory series subject to structural change: A two-stage approach

    DEFF Research Database (Denmark)

    Papailias, Fotis; Dias, Gustavo Fruet

    2015-01-01

    A two-stage forecasting approach for long memory time series is introduced. In the first step, we estimate the fractional exponent and, by applying the fractional differencing operator, obtain the underlying weakly dependent series. In the second step, we produce multi-step-ahead forecasts...... for the weakly dependent series and obtain their long memory counterparts by applying the fractional cumulation operator. The methodology applies to both stationary and nonstationary cases. Simulations and an application to seven time series provide evidence that the new methodology is more robust to structural...... change and yields good forecasting results....

  8. Space Station Freedom carbon dioxide removal assembly two-stage rotary sliding vane pump

    Science.gov (United States)

    Matteau, Dennis

    1992-07-01

    The design and development of a positive displacement pump selected to operate as an essential part of the carbon dioxide removal assembly (CDRA) are described. An oilless two-stage rotary sliding vane pump was selected as the optimum concept to meet the CDRA application requirements. This positive displacement pump is characterized by low weight and small envelope per unit flow, ability to pump saturated gases and moderate amount of liquid, small clearance volumes, and low vibration. It is easily modified to accommodate several stages on a single shaft optimizing space and weight, which makes the concept ideal for a range of demanding space applications.

  9. Two-Stage Maximum Likelihood Estimation (TSMLE for MT-CDMA Signals in the Indoor Environment

    Directory of Open Access Journals (Sweden)

    Sesay Abu B

    2004-01-01

    Full Text Available This paper proposes a two-stage maximum likelihood estimation (TSMLE technique suited for multitone code division multiple access (MT-CDMA system. Here, an analytical framework is presented in the indoor environment for determining the average bit error rate (BER of the system, over Rayleigh and Ricean fading channels. The analytical model is derived for quadrature phase shift keying (QPSK modulation technique by taking into account the number of tones, signal bandwidth (BW, bit rate, and transmission power. Numerical results are presented to validate the analysis, and to justify the approximations made therein. Moreover, these results are shown to agree completely with those obtained by simulation.

  10. Two-Stage Electric Vehicle Charging Coordination in Low Voltage Distribution Grids

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

    2014-01-01

    Increased environmental awareness in the recent years has encouraged rapid growth of renewable energy sources (RESs); especially solar PV and wind. One of the effective solutions to compensate intermittencies in generation from the RESs is to enable consumer participation in demand response (DR......). Being a sizable rated element, electric vehicles (EVs) can offer a great deal of demand flexibility in future intelligent grids. This paper first investigates and analyzes driving pattern and charging requirements of EVs. Secondly, a two-stage charging algorithm, namely local adaptive control...

  11. The global stability of a delayed predator-prey system with two stage-structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang Fengyan [College of Science, Jimei University, Xiamen Fujian 361021 (China)], E-mail: wangfy68@163.com; Pang Guoping [Department of Mathematics and Computer Science, Yulin Normal University, Yulin Guangxi 537000 (China)

    2009-04-30

    Based on the classical delayed stage-structured model and Lotka-Volterra predator-prey model, we introduce and study a delayed predator-prey system, where prey and predator have two stages, an immature stage and a mature stage. The time delays are the time lengths between the immature's birth and maturity of prey and predator species. Results on global asymptotic stability of nonnegative equilibria of the delay system are given, which generalize and suggest that good continuity exists between the predator-prey system and its corresponding stage-structured system.

  12. A Two-Stage Assembly-Type Flowshop Scheduling Problem for Minimizing Total Tardiness

    Directory of Open Access Journals (Sweden)

    Ju-Yong Lee

    2016-01-01

    Full Text Available This research considers a two-stage assembly-type flowshop scheduling problem with the objective of minimizing the total tardiness. The first stage consists of two independent machines, and the second stage consists of a single machine. Two types of components are fabricated in the first stage, and then they are assembled in the second stage. Dominance properties and lower bounds are developed, and a branch and bound algorithm is presented that uses these properties and lower bounds as well as an upper bound obtained from a heuristic algorithm. The algorithm performance is evaluated using a series of computational experiments on randomly generated instances and the results are reported.

  13. Structural requirements and basic design concepts for a two-stage winged launcher system (Saenger)

    Science.gov (United States)

    Kuczera, H.; Keller, K.; Kunz, R.

    1988-10-01

    An evaluation is made of materials and structures technologies deemed capable of increasing the mass fraction-to-orbit of the Saenger two-stage launcher system while adequately addressing thermal-control and cryogenic fuel storage insulation problems. Except in its leading edges, nose cone, and airbreathing propulsion system air intakes, Ti alloy-based materials will be the basis of the airframe primary structure. Lightweight metallic thermal-protection measures will be employed. Attention is given to the design of the large lower stage element of Saenger.

  14. FORMATION OF HIGHLY RESISTANT CARBIDE AND BORIDE COATINGS BY A TWO-STAGE DEPOSITION METHOD

    Directory of Open Access Journals (Sweden)

    W. I. Sawich

    2011-01-01

    Full Text Available A study was made of the aspects of forming highly resistant coatings in the surface zone of tool steels and solid carbide inserts by a two-stage method. at the first stage of the method, pure Ta or Nb coatings were electrodeposited on samples of tool steel and solid carbide insert in a molten salt bath containing Ta and Nb fluorides. at the second stage, the electrodeposited coating of Ta (Nb was subjected to carburizing or boriding to form carbide (TaC, NbC or boride (TaB, NbB cladding layers.

  15. Pilot investigation of two-stage biofiltration for removal of natural organic matter in drinking water treatment.

    Science.gov (United States)

    Fu, Jie; Lee, Wan-Ning; Coleman, Clark; Meyer, Melissa; Carter, Jason; Nowack, Kirk; Huang, Ching-Hua

    2017-01-01

    A pilot study employing two parallel trains of two-stage biofiltration, i.e., a sand/anthracite (SA) biofilter followed by a biologically-active granular activated carbon (GAC) contactor, was conducted to test the efficiency, feasibility and stability of biofiltration for removing natural organic matter (NOM) after coagulation in a drinking water treatment plant. Results showed the biofiltration process could effectively remove turbidity (24% of dissolved organic carbon (DOC), >57% of UV254, and >44% of SUVA254), where the SA biofilters showed a strong capacity for turbidity removal, while the GAC contactors played the dominant role in NOM removal. The vertical profile of water quality in the GAC contactors indicated the middle-upper portion was the critical zone for the removal of NOM, where relatively higher adsorption and enhanced biological removal were afforded. Fluorescence excitation-emission matrix (EEM) analysis of NOM showed that the GAC contactors effectively decreased the content of humic-like component, while protein-like component was refractory for the biofiltration process. Nutrients (NH4-N and PO4-P) supplementation applied upstream of one of the two-stage biofiltration trains (called engineered biofiltration) stimulated the growth of microorganisms, and showed a modest effect on promoting the biological removal of small non-aromatic compositions in NOM. Redundancy analysis (RDA) indicated influent UV254 was the most explanatory water quality parameter for GAC contactors' treatment performance, and a high load of UV254 would result in significantly reduced removals of UV254 and SUVA254. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Consistency check of photon beam physical data after recommissioning process

    Science.gov (United States)

    Kadman, B.; Chawapun, N.; Ua-apisitwong, S.; Asakit, T.; Chumpu, N.; Rueansri, J.

    2016-03-01

    In radiotherapy, medical linear accelerator (Linac) is the key system used for radiation treatments delivery. Although, recommissioning was recommended after major modification of the machine by AAPM TG53, but it might not be practical in radiotherapy center with heavy workloads. The main purpose of this study was to compare photon beam physical data between initial commissioning and recommissioning of 6 MV Elekta Precise linac. The parameters for comparing were the percentage depth dose (PDD) and beam profiles. The clinical commissioning test cases followed IAEA-TECDOC-1583 were planned on REF 91230 IMRT Dose Verification Phantom by Philips’ Pinnacle treatment planning system. The Delta4PT was used for dose distribution verification with 90% passing criteria of the gamma index (3%/3mm). Our results revealed that the PDDs and beam profiles agreed within a tolerance limit recommended by TRS430. Most of the point doses and dose distribution verification passed the acceptance criteria. This study showed the consistency of photon beam physical data after recommissioning process. There was a good agreement between initial commissioning and recommissioning within a tolerance limit, demonstrated that the full recommissioning process might not be required. However, in the complex treatment planning geometry, the initial data should be applied with great caution.

  17. Physical anthropology: the search for general processes and principles.

    Science.gov (United States)

    Lasker, G W

    1970-02-01

    Physical anthropology consists of two interdependent types of study: (1) the biological history of man and (2) general biological processes in man (such as mechanisms of evolution and growth). Popular interest may focus on the former, the fascinating story of the origin of man and of specific people, but the latter affords physical anthropology potential practical value in respect to medicine, dentistry, public health, and population policy. The study of general processes is the study of human beings in particular situations, not for what we can learn about these particular populations but for the sake of generalization about mankind anywhere in comparable situations. This is, of course, the purpose of experimental science in general, but in anthropology the method is usually comparative. Long ago the study of the growth of the two sexes and of children in different countries was started on a comparative basis as was the study of the so-called secular change in adult stature. By 1911 Franz Boas had compared the changes in stature and head form of children of several different immigrant groups in the United States. There have since been comparative studies of the amount and distribution of body fat (but not yet adequate comparative measurements of the relation of tissue components to diet and to diseases). Demographic patterns, inbreeding, outbreeding, and their effects are other general problems. The Human Adaptability Project of the International Biological Program promises studies of human response to heat, cold, altitude, and other conditions on a wide international basis. If supported, these could turn physical anthropology's search in a useful direction. The functional biology of people of even out-of-the-way communities will be compared with each other. These studies can yield general statements concerning human response to types of ecological situation including such sociocultural conditions as those of hunting-gathering tribes and urban slums.

  18. Direct and two-stage data analysis procedures based on PCA, PLS-DA and ANN for ISE-based electronic tongue-Effect of supervised feature extraction.

    Science.gov (United States)

    Ciosek, P; Brzózka, Z; Wróblewski, W; Martinelli, E; Di Natale, C; D'Amico, A

    2005-09-15

    A novel strategy of data analysis for artificial taste and odour systems is presented in this work. It is demonstrated that using a supervised method also in feature extraction phase enhances fruit juice classification capability of sensor array developed at Warsaw University of Technology. Comparison of direct processing (raw data processed by Artificial Neural Network (ANN), raw data processed by Partial Least Squares-Discriminant Analysis (PLS-DA)) and two-stage processing (Principal Components Analysis (PCA) outputs processed by ANN, PLS-DA outputs processed by ANN) is presented. It is shown that considerable increase of classification capability occurred in the case of the new method proposed by the authors.

  19. Guidelines for Automatic Data Processing Physical Security and Risk Management. Federal Information Processing Standards Publication 31.

    Science.gov (United States)

    National Bureau of Standards (DOC), Washington, DC.

    These guidelines provide a handbook for use by federal organizations in structuring physical security and risk management programs for their automatic data processing facilities. This publication discusses security analysis, natural disasters, supporting utilities, system reliability, procedural measures and controls, off-site facilities,…

  20. Complex Dynamical Behavior of a Two-Stage Colpitts Oscillator with Magnetically Coupled Inductors

    Directory of Open Access Journals (Sweden)

    V. Kamdoum Tamba

    2014-01-01

    Full Text Available A five-dimensional (5D controlled two-stage Colpitts oscillator is introduced and analyzed. This new electronic oscillator is constructed by considering the well-known two-stage Colpitts oscillator with two further elements (coupled inductors and variable resistor. In contrast to current approaches based on piecewise linear (PWL model, we propose a smooth mathematical model (with exponential nonlinearity to investigate the dynamics of the oscillator. Several issues, such as the basic dynamical behaviour, bifurcation diagrams, Lyapunov exponents, and frequency spectra of the oscillator, are investigated theoretically and numerically by varying a single control resistor. It is found that the oscillator moves from the state of fixed point motion to chaos via the usual paths of period-doubling and interior crisis routes as the single control resistor is monitored. Furthermore, an experimental study of controlled Colpitts oscillator is carried out. An appropriate electronic circuit is proposed for the investigations of the complex dynamics behaviour of the system. A very good qualitative agreement is obtained between the theoretical/numerical and experimental results.

  1. Optimization of Two-Stage Peltier Modules: Structure and Exergetic Efficiency

    Directory of Open Access Journals (Sweden)

    Cesar Ramirez-Lopez

    2012-08-01

    Full Text Available In this paper we undertake the theoretical analysis of a two-stage semiconductor thermoelectric module (TEM which contains an arbitrary and different number of thermocouples, n1 and n2, in each stage (pyramid-styled TEM. The analysis is based on a dimensionless entropy balance set of equations. We study the effects of n1 and n2, the flowing electric currents through each stage, the applied temperatures and the thermoelectric properties of the semiconductor materials on the exergetic efficiency. Our main result implies that the electric currents flowing in each stage must necessarily be different with a ratio about 4.3 if the best thermal performance and the highest temperature difference possible between the cold and hot side of the device are pursued. This fact had not been pointed out before for pyramid-styled two stage TEM. The ratio n1/n2 should be about 8.

  2. A two-stage series diode for intense large-area moderate pulsed X rays production

    Science.gov (United States)

    Lai, Dingguo; Qiu, Mengtong; Xu, Qifu; Su, Zhaofeng; Li, Mo; Ren, Shuqing; Huang, Zhongliang

    2017-01-01

    This paper presents a method for moderate pulsed X rays produced by a series diode, which can be driven by high voltage pulse to generate intense large-area uniform sub-100-keV X rays. A two stage series diode was designed for Flash-II accelerator and experimentally investigated. A compact support system of floating converter/cathode was invented, the extra cathode is floating electrically and mechanically, by withdrawing three support pins several milliseconds before a diode electrical pulse. A double ring cathode was developed to improve the surface electric field and emission stability. The cathode radii and diode separation gap were optimized to enhance the uniformity of X rays and coincidence of the two diode voltages based on the simulation and theoretical calculation. The experimental results show that the two stage series diode can work stably under 700 kV and 300 kA, the average energy of X rays is 86 keV, and the dose is about 296 rad(Si) over 615 cm2 area with uniformity 2:1 at 5 cm from the last converter. Compared with the single diode, the average X rays' energy reduces from 132 keV to 88 keV, and the proportion of sub-100-keV photons increases from 39% to 69%.

  3. Study on a high capacity two-stage free piston Stirling cryocooler working around 30 K

    Science.gov (United States)

    Wang, Xiaotao; Zhu, Jian; Chen, Shuai; Dai, Wei; Li, Ke; Pang, Xiaomin; Yu, Guoyao; Luo, Ercang

    2016-12-01

    This paper presents a two-stage high-capacity free-piston Stirling cryocooler driven by a linear compressor to meet the requirement of the high temperature superconductor (HTS) motor applications. The cryocooler system comprises a single piston linear compressor, a two-stage free piston Stirling cryocooler and a passive oscillator. A single stepped displacer configuration was adopted. A numerical model based on the thermoacoustic theory was used to optimize the system operating and structure parameters. Distributions of pressure wave, phase differences between the pressure wave and the volume flow rate and different energy flows are presented for a better understanding of the system. Some characterizing experimental results are presented. Thus far, the cryocooler has reached a lowest cold-head temperature of 27.6 K and achieved a cooling power of 78 W at 40 K with an input electric power of 3.2 kW, which indicates a relative Carnot efficiency of 14.8%. When the cold-head temperature increased to 77 K, the cooling power reached 284 W with a relative Carnot efficiency of 25.9%. The influences of different parameters such as mean pressure, input electric power and cold-head temperature are also investigated.

  4. Planning an Agricultural Water Resources Management System: A Two-Stage Stochastic Fractional Programming Model

    Directory of Open Access Journals (Sweden)

    Liang Cui

    2015-07-01

    Full Text Available Irrigation water management is crucial for agricultural production and livelihood security in many regions and countries throughout the world. In this study, a two-stage stochastic fractional programming (TSFP method is developed for planning an agricultural water resources management system under uncertainty. TSFP can provide an effective linkage between conflicting economic benefits and the associated penalties; it can also balance conflicting objectives and maximize the system marginal benefit with per unit of input under uncertainty. The developed TSFP method is applied to a real case of agricultural water resources management of the Zhangweinan River Basin China, which is one of the main food and cotton producing regions in north China and faces serious water shortage. The results demonstrate that the TSFP model is advantageous in balancing conflicting objectives and reflecting complicated relationships among multiple system factors. Results also indicate that, under the optimized irrigation target, the optimized water allocation rate of Minyou Channel and Zhangnan Channel are 57.3% and 42.7%, respectively, which adapts the changes in the actual agricultural water resources management problem. Compared with the inexact two-stage water management (ITSP method, TSFP could more effectively address the sustainable water management problem, provide more information regarding tradeoffs between multiple input factors and system benefits, and help the water managers maintain sustainable water resources development of the Zhangweinan River Basin.

  5. A separate two-stage pulse tube cooler working at liquid helium temperature

    Institute of Scientific and Technical Information of China (English)

    QIU Limin; HE Yonglin; GAN Zhihua; WAN Laihong; CHEN Guobang

    2005-01-01

    A novel 4 K separate two-stage pulse tube cooler (PTC) was designed and tested. The cooler consists of two separate pulse tube coolers, in which the cold end of the first stage regenerator is thermally connected with the middle part of the second regenerator. Compared to the traditional coupled multi-stage pulse tube cooler, the mutual interference between stages can be significantly eliminated. The lowest refrigeration temperature obtained at the first stage pulse tube was 13.8 K. This is a new record for single stage PTC. With two compressors and two rotary valves driving mode, the separate two-stage PTC obtained a refrigeration temperature of 2.5 K at the second stage. Cooling capacities of 508 mW at 4.2 K and 15 W at 37.5 K were achieved simultaneously. A one-compressor and one-rotary valve driving mode has been proposed to further simplify the structure of separate type PTC.

  6. Multiobjective Two-Stage Stochastic Programming Problems with Interval Discrete Random Variables

    Directory of Open Access Journals (Sweden)

    S. K. Barik

    2012-01-01

    Full Text Available Most of the real-life decision-making problems have more than one conflicting and incommensurable objective functions. In this paper, we present a multiobjective two-stage stochastic linear programming problem considering some parameters of the linear constraints as interval type discrete random variables with known probability distribution. Randomness of the discrete intervals are considered for the model parameters. Further, the concepts of best optimum and worst optimum solution are analyzed in two-stage stochastic programming. To solve the stated problem, first we remove the randomness of the problem and formulate an equivalent deterministic linear programming model with multiobjective interval coefficients. Then the deterministic multiobjective model is solved using weighting method, where we apply the solution procedure of interval linear programming technique. We obtain the upper and lower bound of the objective function as the best and the worst value, respectively. It highlights the possible risk involved in the decision-making tool. A numerical example is presented to demonstrate the proposed solution procedure.

  7. Two-Stage Single-Compartment Models to Evaluate Dissolution in the Lower Intestine.

    Science.gov (United States)

    Markopoulos, Constantinos; Vertzoni, Maria; Symillides, Mira; Kesisoglou, Filippos; Reppas, Christos

    2015-09-01

    The purpose was to propose two-stage single-compartment models for evaluating dissolution characteristics in distal ileum and ascending colon, under conditions simulating the bioavailability and bioequivalence studies in fasted and fed state by using the mini-paddle and the compendial flow-through apparatus (closed-loop mode). Immediate release products of two highly dosed active pharmaceutical ingredients (APIs), sulfasalazine and L-870,810, and one mesalamine colon targeting product were used for evaluating their usefulness. Change of medium composition simulating the conditions in distal ileum (SIFileum ) to a medium simulating the conditions in ascending colon in fasted state and in fed state was achieved by adding an appropriate solution in SIFileum . Data with immediate release products suggest that dissolution in lower intestine is substantially different than in upper intestine and is affected by regional pH differences > type/intensity of fluid convection > differences in concentration of other luminal components. Asacol® (400 mg/tab) was more sensitive to type/intensity of fluid convection. In all the cases, data were in line with available human data. Two-stage single-compartment models may be useful for the evaluation of dissolution in lower intestine. The impact of type/intensity of fluid convection and viscosity of media on luminal performance of other APIs and drug products requires further exploration.

  8. Simultaneous bile duct and portal venous branch ligation in two-stage hepatectomy

    Institute of Scientific and Technical Information of China (English)

    Hiroya Iida; Chiaki Yasui; Tsukasa Aihara; Shinichi Ikuta; Hidenori Yoshie; Naoki Yamanaka

    2011-01-01

    Hepatectomy is an effective surgical treatment for multiple bilobar liver metastases from colon cancer; however, one of the primary obstacles to completing surgical resection for these cases is an insufficient volume of the future remnant liver, which may cause postoperative liver failure. To induce atrophy of the unilateral lobe and hypertrophy of the future remnant liver, procedures to occlude the portal vein have been conventionally used prior to major hepatectomy. We report a case of a 50-year-old woman in whom two-stage hepatectomy was performed in combination with intraoperative ligation of the portal vein and the bile duct of the right hepatic lobe. This procedure was designed to promote the atrophic effect on the right hepatic lobe more effectively than the conventional technique, and to the best of our knowledge, it was used for the first time in the present case. Despite successful induction of liver volume shift as well as the following procedure, the patient died of subsequent liver failure after developing recurrent tumors. We discuss the first case in which simultaneous ligation of the portal vein and the biliary system was successfully applied as part of the first step of two-stage hepatectomy.

  9. On bi-criteria two-stage transportation problem: a case study

    Directory of Open Access Journals (Sweden)

    Ahmad MURAD

    2010-01-01

    Full Text Available The study of the optimum distribution of goods between sources and destinations is one of the important topics in projects economics. This importance comes as a result of minimizing the transportation cost, deterioration, time, etc. The classical transportation problem constitutes one of the major areas of application for linear programming. The aim of this problem is to obtain the optimum distribution of goods from different sources to different destinations which minimizes the total transportation cost. From the practical point of view, the transportation problems may differ from the classical form. It may contain one or more objective function, one or more stage to transport, one or more type of commodity with one or more means of transport. The aim of this paper is to construct an optimization model for transportation problem for one of mill-stones companies. The model is formulated as a bi-criteria two-stage transportation problem with a special structure depending on the capacities of suppliers, warehouses and requirements of the destinations. A solution algorithm is introduced to solve this class of bi-criteria two-stage transportation problem to obtain the set of non-dominated extreme points and the efficient solutions accompanied with each one that enables the decision maker to choose the best one. The solution algorithm mainly based on the fruitful application of the methods for treating transportation problems, theory of duality of linear programming and the methods of solving bi-criteria linear programming problems.

  10. Dynamics of installation way for the actuator of a two-stage active vibration-isolator

    Institute of Scientific and Technical Information of China (English)

    HU Li; HUANG Qi-bai; HE Xue-song; YUAN Ji-xuan

    2008-01-01

    We investigated the behaviors of an active control system of two-stage vibration isolation with the actuator installed in parallel with either the upper passive mount or the lower passive isolation mount. We revealed the relationships between the active control force of the actuator and the parameters of the passive isolators by studying the dynamics of two-stage active vibration isolation for the actuator at the foregoing two positions in turn. With the actuator installed beside the upper mount, a small active force can achieve a very good isolating effect when the frequency of the stimulating force is much larger than the natural frequency of the upper mount; a larger active force is required in the low-frequency domain; and the active force equals the stimulating force when the upper mount works within the resonance region, suggesting an approach to reducing wobble and ensuring desirable installation accuracy by increasing the upper-mount stiffness. In either the low or the high frequency region far away from the resonance region, the active force is smaller when the actuator is beside the lower mount than beside the upper mount.

  11. Final Report on Two-Stage Fast Spectrum Fuel Cycle Options

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Won Sik [Purdue Univ., West Lafayette, IN (United States); Lin, C. S. [Purdue Univ., West Lafayette, IN (United States); Hader, J. S. [Purdue Univ., West Lafayette, IN (United States); Park, T. K. [Purdue Univ., West Lafayette, IN (United States); Deng, P. [Purdue Univ., West Lafayette, IN (United States); Yang, G. [Purdue Univ., West Lafayette, IN (United States); Jung, Y. S. [Purdue Univ., West Lafayette, IN (United States); Kim, T. K. [Argonne National Lab. (ANL), Argonne, IL (United States); Stauff, N. E. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-30

    This report presents the performance characteristics of two “two-stage” fast spectrum fuel cycle options proposed to enhance uranium resource utilization and to reduce nuclear waste generation. One is a two-stage fast spectrum fuel cycle option of continuous recycle of plutonium (Pu) in a fast reactor (FR) and subsequent burning of minor actinides (MAs) in an accelerator-driven system (ADS). The first stage is a sodium-cooled FR fuel cycle starting with low-enriched uranium (LEU) fuel; at the equilibrium cycle, the FR is operated using the recovered Pu and natural uranium without supporting LEU. Pu and uranium (U) are co-extracted from the discharged fuel and recycled in the first stage, and the recovered MAs are sent to the second stage. The second stage is a sodium-cooled ADS in which MAs are burned in an inert matrix fuel form. The discharged fuel of ADS is reprocessed, and all the recovered heavy metals (HMs) are recycled into the ADS. The other is a two-stage FR/ADS fuel cycle option with MA targets loaded in the FR. The recovered MAs are not directly sent to ADS, but partially incinerated in the FR in order to reduce the amount of MAs to be sent to the ADS. This is a heterogeneous recycling option of transuranic (TRU) elements

  12. Occurrence of two-stage hardening in C-Mn steel wire rods containing pearlitic microstructure

    Science.gov (United States)

    Singh, Balbir; Sahoo, Gadadhar; Saxena, Atul

    2016-09-01

    The 8 and 10 mm diameter wire rods intended for use as concrete reinforcement were produced/ hot rolled from C-Mn steel chemistry containing various elements within the range of C:0.55-0.65, Mn:0.85-1.50, Si:0.05-0.09, S:0.04 max, P:0.04 max and N:0.006 max wt%. Depending upon the C and Mn contents the product attained pearlitic microstructure in the range of 85-93% with balance amount of polygonal ferrite transformed at prior austenite grain boundaries. The pearlitic microstructure in the wire rods helped in achieving yield strength, tensile strength, total elongation and reduction in area values within the range of 422-515 MPa, 790-950 MPa, 22-15% and 45-35%, respectively. On analyzing the tensile results it was revealed that the material experienced hardening in two stages separable by a knee strain value of about 0.05. The occurrence of two stage hardening thus in the steel with hardening coefficients of 0.26 and 0.09 could be demonstrated with the help of derived relationships existed between flow stress and the strain.

  13. Rules and mechanisms for efficient two-stage learning in neural circuits

    Science.gov (United States)

    Teşileanu, Tiberiu; Ölveczky, Bence; Balasubramanian, Vijay

    2017-01-01

    Trial-and-error learning requires evaluating variable actions and reinforcing successful variants. In songbirds, vocal exploration is induced by LMAN, the output of a basal ganglia-related circuit that also contributes a corrective bias to the vocal output. This bias is gradually consolidated in RA, a motor cortex analogue downstream of LMAN. We develop a new model of such two-stage learning. Using stochastic gradient descent, we derive how the activity in ‘tutor’ circuits (e.g., LMAN) should match plasticity mechanisms in ‘student’ circuits (e.g., RA) to achieve efficient learning. We further describe a reinforcement learning framework through which the tutor can build its teaching signal. We show that mismatches between the tutor signal and the plasticity mechanism can impair learning. Applied to birdsong, our results predict the temporal structure of the corrective bias from LMAN given a plasticity rule in RA. Our framework can be applied predictively to other paired brain areas showing two-stage learning. DOI: http://dx.doi.org/10.7554/eLife.20944.001 PMID:28374674

  14. Two-stage earth-to-orbit vehicles with dual-fuel propulsion in the Orbiter

    Science.gov (United States)

    Martin, J. A.

    1982-01-01

    Earth-to-orbit vehicle studies of future replacements for the Space Shuttle are needed to guide technology development. Previous studies that have examined single-stage vehicles have shown advantages for dual-fuel propulsion. Previous two-stage system studies have assumed all-hydrogen fuel for the Orbiters. The present study examined dual-fuel Orbiters and found that the system dry mass could be reduced with this concept. The possibility of staging the booster at a staging velocity low enough to allow coast-back to the launch site is shown to be beneficial, particularly in combination with a dual-fuel Orbiter. An engine evaluation indicated the same ranking of engines as did a previous single-stage study. Propane and RP-1 fuels result in lower vehicle dry mass than methane, and staged-combustion engines are preferred over gas-generator engines. The sensitivity to the engine selection is less for two-stage systems than for single-stage systems.

  15. Configuration Consideration for Expander in Transcritical Carbon Dioxide Two-Stage Compression Cycle

    Institute of Scientific and Technical Information of China (English)

    MA Yitai; YANG Junlan; GUAN Haiqing; LI Minxia

    2005-01-01

    To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve the system efficiency. The expander and the compressor are connected to the same shaft and integrated into one unit, with the latter being driven by the former, thus the transfer loss and leakage loss can be decreased greatly. In these systems, the expander can be either connected with the first stage compressor (shortened as DCDL cycle) or the second stage compressor (shortened as DCDH cycle), but the two configuration ways can get different performances. By setting up theoretical model for two kinds of expander configuration ways in the transcritical carbon dioxide two-stage compression cycle, the first and the second laws of thermodynamics are used to analyze the coefficient of performance, exergy efficiency, inter-stage pressure, discharge temperature and exergy losses of each component for the two cycles. From the model results, the performance of DCDH cycle is better than that of DCDL cycle. The analysis results are indispensable to providing a theoretical basis for practical design and operating.

  16. Two-stage coordination multi-radio multi-channel mac protocol for wireless mesh networks

    CERN Document Server

    Zhao, Bingxuan

    2011-01-01

    Within the wireless mesh network, a bottleneck problem arises as the number of concurrent traffic flows (NCTF) increases over a single common control channel, as it is for most conventional networks. To alleviate this problem, this paper proposes a two-stage coordination multi-radio multi-channel MAC (TSC-M2MAC) protocol that designates all available channels as both control channels and data channels in a time division manner through a two-stage coordination. At the first stage, a load balancing breadth-first-search-based vertex coloring algorithm for multi-radio conflict graph is proposed to intelligently allocate multiple control channels. At the second stage, a REQ/ACK/RES mechanism is proposed to realize dynamical channel allocation for data transmission. At this stage, the Channel-and-Radio Utilization Structure (CRUS) maintained by each node is able to alleviate the hidden nodes problem; also, the proposed adaptive adjustment algorithm for the Channel Negotiation and Allocation (CNA) sub-interval is ab...

  17. Two-stage image segmentation based on edge and region information

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A two-stage method for image segmentation based on edge and region information is proposed. Different deformation schemes are used at two stages for segmenting the object correctly in image plane. At the first stage, the contour of the model is divided into several segments hierarchically that deform respectively using affine transformation. After the contour is deformed to the approximate boundary of object, a fine match mechanism using statistical information of local region to redefine the external energy of the model is used to make the contour fit the object's boundary exactly. The algorithm is effective, as the hierarchical segmental deformation makes use of the globe and local information of the image, the affine transformation keeps the consistency of the model, and the reformative approaches of computing the internal energy and external energy are proposed to reduce the algorithm complexity. The adaptive method of defining the search area at the second stage makes the model converge quickly. The experimental results indicate that the proposed model is effective and robust to local minima and able to search for concave objects.

  18. Two-Stage Orthogonal Least Squares Methods for Neural Network Construction.

    Science.gov (United States)

    Zhang, Long; Li, Kang; Bai, Er-Wei; Irwin, George W

    2015-08-01

    A number of neural networks can be formulated as the linear-in-the-parameters models. Training such networks can be transformed to a model selection problem where a compact model is selected from all the candidates using subset selection algorithms. Forward selection methods are popular fast subset selection approaches. However, they may only produce suboptimal models and can be trapped into a local minimum. More recently, a two-stage fast recursive algorithm (TSFRA) combining forward selection and backward model refinement has been proposed to improve the compactness and generalization performance of the model. This paper proposes unified two-stage orthogonal least squares methods instead of the fast recursive-based methods. In contrast to the TSFRA, this paper derives a new simplified relationship between the forward and the backward stages to avoid repetitive computations using the inherent orthogonal properties of the least squares methods. Furthermore, a new term exchanging scheme for backward model refinement is introduced to reduce computational demand. Finally, given the error reduction ratio criterion, effective and efficient forward and backward subset selection procedures are proposed. Extensive examples are presented to demonstrate the improved model compactness constructed by the proposed technique in comparison with some popular methods.

  19. Two-stage numerical simulation for temperature profile in furnace of tangentially fired pulverized coal boiler

    Institute of Scientific and Technical Information of China (English)

    ZHOU Nai-jun; XU Qiong-hui; ZHOU Ping

    2005-01-01

    Considering the fact that the temperature distribution in furnace of a tangential fired pulverized coal boiler is difficult to be measured and monitored, two-stage numerical simulation method was put forward. First, multi-field coupling simulation in typical work conditions was carried out off-line with the software CFX-4.3, and then the expression of temperature profile varying with operating parameter was obtained. According to real-time operating parameters, the temperature at arbitrary point of the furnace can be calculated by using this expression. Thus the temperature profile can be shown on-line and monitoring for combustion state in the furnace is realized. The simul-ation model was checked by the parameters measured in an operating boiler, DG130-9.8/540. The maximum of relative error is less than 12% and the absolute error is less than 120 ℃, which shows that the proposed two-stage simulation method is reliable and able to satisfy the requirement of industrial application.

  20. A low-voltage sense amplifier with two-stage operational amplifier clamping for flash memory

    Science.gov (United States)

    Guo, Jiarong

    2017-04-01

    A low-voltage sense amplifier with reference current generator utilizing two-stage operational amplifier clamp structure for flash memory is presented in this paper, capable of operating with minimum supply voltage at 1 V. A new reference current generation circuit composed of a reference cell and a two-stage operational amplifier clamping the drain pole of the reference cell is used to generate the reference current, which avoids the threshold limitation caused by current mirror transistor in the traditional sense amplifier. A novel reference voltage generation circuit using dummy bit-line structure without pull-down current is also adopted, which not only improves the sense window enhancing read precision but also saves power consumption. The sense amplifier was implemented in a flash realized in 90 nm flash technology. Experimental results show the access time is 14.7 ns with power supply of 1.2 V and slow corner at 125 °C. Project supported by the National Natural Science Fundation of China (No. 61376028).