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Sample records for closed recirculating culture

  1. The Effect of Stocking Density on Nitrification Rate in a Closed Recirculating Culture System

    Directory of Open Access Journals (Sweden)

    A.S. Sidik

    2007-08-01

    Full Text Available ABSTRACTNitrification rate in a closed recirculating water system with different stocking density of common carp (Cyprinus carpio L. had been observed in the Laboratory of Aquaculture, Faculty of Fisheries and Marine Science, Mulawarman University.   Fish were cultivated  in rounded tanks with four level of stocking densities i.e. 10, 20, 30 and 40 fish/100 l in a closed recirculting water system, and fed on a commercial pellet given thrice a day at a quantity of 5% from the total body weight of fish per day.  The experiment was designed completely randomized with three replications. Nitrification rate was calculated stoichiometrically through the determination of  ammonia and nitrite oxidation rate. Results showed that in this experiment the ammonia and nitrite oxidation rate, and nitrification rate in a closed recirculating water system was increased with the increasing stocking density of fish.   On the contrary, the growth of fish was decreased with the increasing of stocking density.Key words :  Nitrification rate, stocking density, recirculation system, common carp (Cyprinus carpio L.. ABSTRAKLaju nitrifikasi dalam budidaya sistem resirkulasi air tertutup dengan padat penebaran ikan mas (Cyprinus carpio L. yang berbeda telah diamati di Laboratorium Budidaya Perairan, Fakultas Perikanan dan Ilmu Kelautan Universitas Mulawarman.  Ikan dipelihara dalam tong plastik dengan empat tingkat padat penebaran, yaitu 10, 20, 30 dan 40 ekor/100 l, dan diberi makan pelet komersial tiga kali sehari dengan jumlah 5 % dari berat badan ikan per hari.  Penelitian ini dirancang secara acak lengkap dengan tiga ulangan.  Laju nitrifikasi dihitung secara stoikiometrik melalui penentuan laju oksidasi amoniak dan nitrit. Hasil penelitian menunjukkan bahwa laju oksidasi amoniak dan nitrit serta laju nitrifikasi dalam sistem resirkulasi air tertutup meningkat dengan meningkatnya padat penebaran.  Sebaliknya pertumbuhan ikan menurun dengan meningkatnya

  2. Design validation and performance of closed loop gas recirculation system

    Science.gov (United States)

    Kalmani, S. D.; Joshi, A. V.; Majumder, G.; Mondal, N. K.; Shinde, R. R.

    2016-11-01

    A pilot experimental set up of the India Based Neutrino Observatory's ICAL detector has been operational for the last 4 years at TIFR, Mumbai. Twelve glass RPC detectors of size 2 × 2 m2, with a gas gap of 2 mm are under test in a closed loop gas recirculation system. These RPCs are continuously purged individually, with a gas mixture of R134a (C2H2F4), isobutane (iC4H10) and sulphur hexafluoride (SF6) at a steady rate of 360 ml/h to maintain about one volume change a day. To economize gas mixture consumption and to reduce the effluents from being released into the atmosphere, a closed loop system has been designed, fabricated and installed at TIFR. The pressure and flow rate in the loop is controlled by mass flow controllers and pressure transmitters. The performance and integrity of RPCs in the pilot experimental set up is being monitored to assess the effect of periodic fluctuation and transients in atmospheric pressure and temperature, room pressure variation, flow pulsations, uniformity of gas distribution and power failures. The capability of closed loop gas recirculation system to respond to these changes is also studied. The conclusions from the above experiment are presented. The validations of the first design considerations and subsequent modifications have provided improved guidelines for the future design of the engineering module gas system.

  3. Nutrient Management in Recirculating Hydroponic Culture

    Science.gov (United States)

    Bugbee, Bruce

    2004-01-01

    There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

  4. Recurrent amoebic gill infestation in rainbow trout cultured in a semiclosed water recirculation system

    Science.gov (United States)

    Noble, A.C.; Herman, R.L.; Noga, E.J.; Bullock, G.L.

    1997-01-01

    Five lots of commercially purchased juvenile rainbow trout Oncorhynchus mykiss (17-44 g) stocked in a continuous-production water recirculation system became infested with gilt amoebae. The amoebae were introduced into the recirculation system, as evidenced by their presence on gills of fish held in quarantine tanks. Based on their morphology, as seen in histological sections and by electron microscopy, the amoebae appeared to be more closely related to the family Cochliopodiidae than to other taxa of free living amoebae. Attempts to culture the amoebae in different media, at different temperatures of incubation, and in fish cell culture were not successful. Initial treatment of the recirculation system with formalin at 167 parts per million (ppm) for 1 h eliminated amoebae from the gills. Subsequent treatments of the entire system with formalin at 50-167 ppm reduced the intensity of further infestations.

  5. Cost Characteristics of the African Catfish Culture in Recirculating ...

    African Journals Online (AJOL)

    Recirculating fish production technology re-‐uses water more than once by passing it through treatment processes thereby utilizing less water and space required by conventional ponds to produce similar yields of fish. Economic performance of the African catfish in three recirculating fish production facilities in Ibadan ...

  6. The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture

    International Nuclear Information System (INIS)

    Lin, Y.-F.; Jing, S.-R.; Lee, D.-Y.

    2003-01-01

    Constructed wetlands improved water qualities and consequently increased the shrimp growth and survival in a recirculating system. - A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of the culture tank on the growth and survival of shrimp postlarvae. During an 80-day culture period, the wetland unit operated at a mean hydraulic loading rate of 0.3 m/day and effectively reduced the influent concentrations of 5-day biochemical oxygen demand (BOD 5 , 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO 2 -N, 90%) and nitrate nitrogen (NO 3 -N, 68%). Phosphate (PO 4 -P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO 3 -N in the culture tank water in RAS were significantly (P≤0.05) lower than those in a control aquaculture system (CAS) that simulated static pond culture without wetland treatment. However, no significant difference (P≤0.05) in BOD 5 , TAN and NO 2 -N was found between the two systems. At the end of the study, the harvest results showed that shrimp weight and survival rate in the RAS (3.8±1.8 g/shrimp and 90%) significantly (P≤0.01) exceeded those in the CAS (2.3±1.5 g/shrimp and 71%). This study concludes that constructed wetlands can improve the water quality and provide a good culture environment, consequently increasing the shrimp growth and survival without water exchange, in a recirculating system

  7. Low-dose hydrogen peroxide application in closed recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Good, C.; Pedersen, Per Bovbjerg

    2012-01-01

    The aim of the present work was to simulate water treatment practices with hydrogen peroxide (HP) in recirculating aquaculture systems (RAS). Six identical 1,700-L pilot-scale RAS were divided into two experimental groups based on daily feed allocation and operated under constant conditions...

  8. Membrane biological reactors to remove nitrate, digest biosolids, and eliminate water flushing requirements within replicated recirculation systems culturing rainbow trout

    Science.gov (United States)

    Nutrients, particularly nitrate (NO3), can accumulate to very high levels within low exchange recirculation aquaculture systems (RAS) and negatively impact a number of cultured species. To prevent the harmful effects of nitrate accumulation and to dispose of concentrated waste biosolids, many RAS ar...

  9. THE WATER QUALITY MONITORING IN THE RECIRCULATING SYSTEMS FOR INTENSIVE STURGEON CULTURE

    Directory of Open Access Journals (Sweden)

    C. SAVIN

    2009-10-01

    Full Text Available The major modification of those parameters go to apparition of the biological and physico-chemical imbalance of water environment who produce disturbance to normal way of vital function, that respond through the primary physiological modification (endocrine follow by secondary physiological modification (hormonal, with direct influence over the growing parameters and the pathological condition. The rearing experiments were lasting 60 days and have been achieved on young beluga sturgeon (Huso huso in two different locations, with two different recirculating pilot systems. Was analyzed the main physico-chemical parameters of sturgeon culture, obtaining 23 - 25°C temperature, 4 – 5 mg/l dissolved oxygen, 7,6 upH pH, 0,02 – 0,23 mg/l ammonia, 0,13 – 0,17 mg/l ammonium, 0,09 – 0,45 mg/l nitrite and 10,55 – 72,06 mg/l nitrate.

  10. Landfill wall revegetation combined with leachate recirculation: a convenient procedure for management of closed landfills.

    Science.gov (United States)

    Del Moro, G; Barca, E; Cassano, D; Di Iaconi, C; Mascolo, G; Brunetti, G

    2014-01-01

    There is a need for a reliable sustainable option to effectively manage the landfill leachate generation. This study presents a simple procedure for the revegetation of the walls of closed landfills, employing the leachate as a fertirrigant. The native plants Lepidium sativum, Lactuca sativa, and Atriplex halimus, which suit the local climate, were chosen for this study in Southern Italy. The methodology was structured into three phases (i) early stage toxicity assessment phase (apical root length and germination tests), (ii) adult plant resistance assessment phase, and (iii) soil properties verification phase. The rationale of the proposed approach was first to look at the distinctive qualities and the potential toxicity in landfill leachates for fertigation purposes. Afterwards, through specific tests, the plants used were ranked in terms of resistance to the aqueous solution that contained leachate. Finally, after long-term irrigation, any possible worsening of soil properties was evaluated. The results demonstrated the real possibility of using blended leachate as a fertigant for the revegetation of the walls of closed landfills. In particular, the plants maintained good health when leachate was blended at concentrations of lower than 25 and 5%, respectively for A. halimus and Lepidium sativum. Irrigation tests showed good resistance of the plants, even at dosages of 112 and 133.5 mm m(-2), at maximum concentrations of 25 and 5%, respectively, for A. halimus and Lepidium sativum. The analysis of the total chlorophyll content and of aerial parts dried weight confirmed the results reported above.

  11. A semi-closed recirculating system for the in situ study of feeding and respiration of benthic suspension feeders

    Directory of Open Access Journals (Sweden)

    Marta Ribes

    2000-12-01

    Full Text Available Suspension feeding is one of the most widespread feeding strategies among benthic organisms. However, natural feeding ecology and energetics of benthic suspension feeders are poorly known. The scarcity of field methods, apparatus and protocols that facilitate obtention of reliable in situ data has contributed to this lack of knowledge. A detailed description of an improved semi-closed recirculating system as well as the experimental set up is provided for the study of energetics in benthic suspension feeders. The system, completely submersible and surface-independent, allows us to assess oxygen concentration changes and feeding rates under natural conditions. Methodological examinations are conducted to investigate: a the circulation of the water within the chamber; b the time required for the flushing pump to entirely renew the volume of water of the incubation chambers; c the behavior of the species within the chambers; d the time of acclimation to the chamber conditions for the different species; e the maximum decrease in oxygen concentration without affecting respiration rate; f the time required to detect changes in concentration of the natural food sources. The system and experimental protocol is tested with species from three representative phyla, Porifera, Cnidaria and Tunicata.

  12. Optimization of blue mussel (Mytilus edulis) seed culture using recirculation aquaculture systems

    NARCIS (Netherlands)

    Blanco Garcia, A.; Kamermans, P.

    2015-01-01

    By introducing recirculation aquaculture systems (RAS) in the nursery phase of the blue mussel (Mytilus edulis) (17–18 mm), we aimed at a similar growth and survival and a similar water quality compared to the commonly used flow-through systems (FTS). To calculate water flow and size of the

  13. Experimental investigation of a local recirculation photobioreactor for mass cultures of photosynthetic microorganisms.

    Science.gov (United States)

    Moroni, Monica; Cicci, Agnese; Bravi, Marco

    2014-04-01

    The present work deals with the experimental fluid mechanics analysis of a wavy-bottomed cascade photobioreactor, to characterize the extent and period of recirculatory and straight-flowing streams establishing therein as a function of reactor inclination and liquid flow rate. The substream characterization via Feature Tracking (FT) showed that a local recirculation zone establishes in each vane only at inclinations ≤6° and that its location changes from the lower (≤3°) to the upper part of each vane (6°). A straight-flowing stream flows opposite (above or below) the local recirculation stream. The recirculation time ranges from 0.86 s to 0.23 s, corresponding, respectively, to the minimum flow rate at the minimum inclination and to the maximum flow rate at the maximum inclination where recirculation was observed. The increase of photosynthetic activity, resulting from the entailed "flash effect", was estimated to range between 102 and 113% with respect to equivalent tubular and bubble column photobioreactors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Experimental development of an intra-abdominal chemohyperthermia model using a closed abdomen technique and a PRS-1.0 Combat CO2 recirculation system.

    Science.gov (United States)

    Sánchez-García, Susana; Padilla-Valverde, David; Villarejo-Campos, Pedro; Martín-Fernández, Jesús; García-Rojo, Marcial; Rodríguez-Martínez, Marta

    2014-04-01

    Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy is the best operative treatment currently available for patients with peritoneal carcinomatosis of ovarian origin. The open abdomen technique is the classic technique for hyperthermic intraperitoneal chemotherapy. We developed a closed abdomen model that improves temperature control and increases exposure of peritoneal surfaces to the drug by recirculating the perfusate. We used a porcine model with 12 female, Large White pigs-4 in the open technique group and 8 in the closed technique CO2 group. We performed cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for 60 minutes using paclitaxel (175 mg/m(2)) at an input temperature of 42°C. Perfusate recirculation was performed under controlled pressure (range, 12-15 mmHg). The infusion of 0.7 L of CO2 via a separate intraperitoneal infusion catheter mixed the perfusate within the peritoneal cavity. Intra-abdominal temperature was assessed using 6 intra-abdominal temperature probes and 2 temperature probes in the inflow and outflow circuits. Drug distribution was assessed using methylene blue staining. Intra-abdominal temperatures remained constant and homogeneous in all intra-abdominal quadrants with a constant input temperature of 42°C and a minimum output temperature of 41.4°C. The infused CO2 caused the fluid to bubble and created agitation inside the abdominal cavity to facilitate a homogeneous distribution of the drug-containing perfusate. The closed recirculation hyperthermia with intraperitoneal chemotherapy technique developed in this study is safe and feasible, and may provide a more homogeneous delivery of heated chemotherapy to the peritoneal cavity in patients with peritoneal malignancies. Copyright © 2014 Mosby, Inc. All rights reserved.

  15. Growth of Trichomycterus punctulatus “Life” in three population densities in intensive culture system with recirculation

    Directory of Open Access Journals (Sweden)

    Segundo Juan López Cubas

    2013-09-01

    Full Text Available The present research was conducted in order to determine the effect of population density on the growth of Trichomycterus punctulatus, in an intensive culture system with recirculation, to which was applied Increasing Stimulus Experimental Design with three treatments without repetition: 2.21 lifes / liter, 2.94 lifes / liter and 3.68 lifes / liter. The fish were fed a diet of 32% protein and were sampled monthly growth as well as physical and chemical parameters of the water. We applied ANOVA and Duncan test. Growth of T. punctulatus was affected by population density in direct, with a higher density of 3.68 lifes / liter: 90.90 mm and 5.95 g; also the overall production per cubic meter and observed the same trend. The physicochemical parameters of the water were similar among treatments and were within the ranges of good development for fish.

  16. Hematologic and plasma chemistry RIs for cultured Striped catfish (Pangasius hypophthalmus) in recirculating aquaculture systems.

    Science.gov (United States)

    Galagarza, Oscar A; Kuhn, David D; Smith, Stephen A; Hrubec, Terry C

    2017-09-01

    Striped catfish (Pangasius hypophthalmus) is a valuable aquaculture fish species produced primarily in Southeast Asia. In the United States, it is bred as an ornamental species. Striped catfish has high productivity and great demand in numerous countries around the world, yet little is known about its normal physiology. The objective of this study was to establish hematologic and blood chemistry RIs for healthy juvenile Striped catfish. Blood samples were collected from 70 Striped catfish raised in recirculating aquaculture systems. Whole blood and plasma samples were analyzed for multiple hematologic and chemistry variables using standard techniques. The RIs for hematology were as follows: PCV 23.5-35.9%, MCV 106.3-156.6 fL, RBC count 1.79-2.75 × 10 6 cells/μL, thrombocytes 26,318-73,333 cells/μL, total WBC count 36,294-94,286 cells/μL, total lymphocytes 18,997-59,998 cells/μL, small lymphocytes 13,763-51,490 cells/μL, large lymphocytes 715-21,200 cells/μL, granulocytes 4504-18,291 cells/μL, and monocytes 0-7549 cells/μL. Plasma chemistry RIs were the following: ALP 32.7-74.6 U/L, AST 20.3-1235.8 U/L, sodium 135.2-147.7 mmol/L, potassium 3.3-5.0 mmol/L, chloride 120.1-133.6 mmol/L, calcium 2.7-3.6 mmol/L, magnesium 0.9-1.3 mmol/L, phosphorous 1.4-2.7 mmol/L, glucose 4.6-7.6 mmol/L, cholesterol 2.8-5.3 mmol/L, total protein 30-42 g/L, albumin 7-11 g/L, globulin 22-32 g/L, albumin:globulin ratio 0.27-0.37, creatinine 0-8 μmol/L, and osmolality 251.8-327.9 mOsm/kg. Reference intervals reported here can help veterinarians and fish health specialists monitor the health status of Striped catfish under recirculating aquaculture conditions for research, exhibition, and production purposes. © 2017 American Society for Veterinary Clinical Pathology.

  17. Florfenicol residues in rainbow trout after oral dosing in recirculating and flow-through culture systems.

    Science.gov (United States)

    Meinertz, J R; Hess, K R; Bernardy, J A; Gaikowski, M P; Whitsel, M; Endris, R G

    2014-12-01

    Aquaflor is a feed premix for fish containing the broad spectrum antibacterial agent florfenicol (FFC) incorporated at a ratio of 50% (w/w). To enhance the effectiveness of FFC for salmonids infected with certain isolates of Flavobacterium psychrophilum causing cold water disease, the FFC dose must be increased from the standard 10 mg·kg⁻¹ body weight (BW)·d⁻¹ for 10 consecutive days. A residue depletion study was conducted to determine whether FFC residues remaining in the fillet tissue after treating fish at an increased dose would be safe for human consumption. Groups of Rainbow Trout Oncorhynchus mykiss (total n = 144; weight range, 126-617 g) were treated with FFC at 20 mg·kg⁻¹ BW·d⁻¹ for 10 d in a flow-through system (FTS) and a recirculating aquaculture system (RAS) each with a water temperature of ∼13°C. The two-tank RAS included a nontreated tank containing 77 fish. Fish were taken from each tank (treated tank, n = 16; nontreated tank, n = 8) at 6, 12, 24, 48, 72, 120, 240, 360, and 480 h posttreatment. Florfenicol amine (FFA) concentrations (the FFC marker residue) in skin-on fillets from treated fish were greatest at 12 h posttreatment (11.58 μg/g) in the RAS and were greatest at 6 h posttreatment (11.09 μg/g) in the FTS. The half-lives for FFA in skin-on fillets from the RAS and FTS were 20.3 and 19.7 h, respectively. Assimilation of FFC residues in the fillets of nontreated fish sharing the RAS with FFC-treated fish was minimal. Florfenicol water concentrations peaked in the RAS-treated tank and nontreated tanks at 10 h (453 μg/L) and 11 h (442 μg/L) posttreatment, respectively. Monitoring of nitrite concentrations throughout the study indicated the nitrogen oxidation efficiency of the RAS biofilter was minimally impacted by the FFC treatment.

  18. Florfenicol residues in Rainbow Trout after oral dosing in recirculating and flow-through culture systems

    Science.gov (United States)

    Meinertz, Jeffery R.; Hess, Karina R.; Bernady, Jeffry A.; Gaikowski, M. P.; Whitsel, Melissa; Endris, R. G.

    2014-01-01

    Aquaflor is a feed premix for fish containing the broad spectrum antibacterial agent florfenicol (FFC) incorporated at a ratio of 50% (w/w). To enhance the effectiveness of FFC for salmonids infected with certain isolates of Flavobacterium psychrophilum causing coldwater disease, the FFC dose must be increased from the standard 10 mg·kg−1 body weight (BW)·d−1 for 10 consecutive days. A residue depletion study was conducted to determine whether FFC residues remaining in the fillet tissue after treating fish at an increased dose would be safe for human consumption. Groups of Rainbow Trout Oncorhynchus mykiss (total n = 144; weight range, 126–617 g) were treated with FFC at 20 mg·kg−1 BW·d−1 for 10 d in a flow-through system (FTS) and a recirculating aquaculture system (RAS) each with a water temperature of ∼13°C. The two-tank RAS included a nontreated tank containing 77 fish. Fish were taken from each tank (treated tank, n = 16; nontreated tank, n = 8) at 6, 12, 24, 48, 72, 120, 240, 360, and 480 h posttreatment. Florfenicol amine (FFA) concentrations (the FFC marker residue) in skin-on fillets from treated fish were greatest at 12 h posttreatment (11.58 μg/g) in the RAS and were greatest at 6 h posttreatment (11.09 μg/g) in the FTS. The half-lives for FFA in skin-on fillets from the RAS and FTS were 20.3 and 19.7 h, respectively. Assimilation of FFC residues in the fillets of nontreated fish sharing the RAS with FFC-treated fish was minimal. Florfenicol water concentrations peaked in the RAS-treated tank and nontreated tanks at 10 h (453 μg/L) and 11 h (442 μg/L) posttreatment, respectively. Monitoring of nitrite concentrations throughout the study indicated the nitrogen oxidation efficiency of the RAS biofilter was minimally impacted by the FFC treatment.

  19. Abnormal swimming behavior and increased deformities in rainbow trout Oncorhynchus mykiss cultured in low exchange water recirculation aquaculture systems

    Science.gov (United States)

    Two studies were conducted to determine if accumulating water quality parameters would negatively impact rainbow trout Oncorhynchus mykiss health and welfare within water recirculation aquaculture systems (WRAS) that were operated at low and near-zero water exchange, with and without ozonation, and ...

  20. Coccolithophorid algae culture in closed photobioreactors.

    Science.gov (United States)

    Moheimani, Navid R; Isdepsky, Andreas; Lisec, Jan; Raes, Eric; Borowitzka, Michael A

    2011-09-01

    The feasibility of growth, calcium carbonate and lipid production of the coccolithophorid algae (Prymnesiophyceae), Pleurochrysis carterae, Emiliania huxleyi, and Gephyrocapsa oceanica, was investigated in plate, carboy, airlift, and tubular photobioreactors. The plate photobioreactor was the most promising closed cultivation system. All species could be grown in the carboy photobioreactor. However, P. carterae was the only species which grew in an airlift photobioreactor. Despite several attempts to grow these coccolithophorid species in the tubular photobioreactor (Biocoil), including modification of the airlift and sparger design, no net growth could be achieved. The shear produced by turbulence and bubble effects are the most likely reasons for this failure to grow in the Biocoil. The highest total dry weight, lipid and calcium carbonate productivities achieved by P. carterae in the plate photobioreactors were 0.54, 0.12, and 0.06 g L(-1) day(-1) respectively. Irrespective of the type of photobioreactor, the productivities were P. carterae > E. huxleyi > G. oceanica. Pleurochrysis carterae lipid (20-25% of dry weight) and calcium carbonate (11-12% of dry weight) contents were also the highest of all species tested. Copyright © 2011 Wiley Periodicals, Inc.

  1. Embryonic development, hatching, mineral consumption, and survival of Macrobrachium rosenbergii (de Man reared in artificial seawater in closed recirculating water system at different levels of salinity

    Directory of Open Access Journals (Sweden)

    Krasindh Hangsapreurke

    2008-08-01

    Full Text Available This experiment aims to study the effect of different levels of salinity (5, 15 and 25 ppt using artificial sea water on the embryonic development and hatching percentage of the eggs of unripe berried female giant freshwater prawns (Macrobrachium rosenbergii with an average size of 14.3+0.6 cm TL. After incubation through the heart beating stage (grayish black eggs, the brooders in each salinity were separately transferred to the hatching tank with 15 ppt saline water for the second part of the study. After hatching, the healthy larvae from the brooders which were previously incubated in 3 levels of salinity were collected for the larviculture experiment. The closed recirculating water system with trickling filter unit packed with fiberglass and bioballs was used as incubation and larviculture units. The metamorphosis period and survival rate were examined. The rearing water from each larviculture aquarium was collected for determination of sodium, magnesium, potassium, calcium and chloride ions. The result showed that the percentage of ripe berried females (with heart beating stage embryos were not significantly different (p>0.05 between 5 and 15 ppt salinity but their values were significantly higher (p0.05 in the survival rate of post larvae and metamorphosis period among the treatments. The first post larvae stage occurred on the 26th day. During 30 days of larviculture, the survival rate of all treatments was 100% until the 19th day, after which it suddenly decreased. When the concentrations of the ions in the rearing water were determined in all treatments, it was found that the concentration of magnesium ions rapidly declined (p0.05. The low survival rate during the final stage of larviculture might be due to the depletion of the previously mentioned ions especially that of magnesium.

  2. Recirculation nursery systems for bivalves

    NARCIS (Netherlands)

    Kamermans, P.; Blanco Garcia, A.; Joaquim, Sandra; Matias, Domitilia; Magnesen, Thorolf; Nicolas, J.; Petten, Bruno; Robert, Rene

    2016-01-01

    n order to increase production of bivalves in hatcheries and nurseries, the development of new technology and its integration into commercial bivalve hatcheries is important. Recirculation aquaculture systems (RASs) have several advantages: high densities of the species can be cultured resulting in

  3. A cultural-spatial analysis of excreting, recirculation of human excreta and health--the case of North West Frontier Province, Pakistan.

    Science.gov (United States)

    Drangert, Jan-Olof; Nawab, Bahadar

    2011-01-01

    The sanitation issue is entering the development discussion and the UN proclaimed 2008 the year of sanitation. The study aims to understand the cultural-spatial dimension among Muslim communities of excreting and recirculating human excreta in North West Frontier Province in Pakistan. Information on local perceptions and cultural understanding was collected through interviews, group discussions and observations in four selected villages. The study identifies a diversity of excreting practices among age groups and sexes, and varied adherence to expressed cultural norms. Interviewees express less resentment towards urine compared to faeces, however, their negative attitude subsides when faecal matter is mixed with water since this changes appearance, odour-and cultural meaning. Religious dictums about excreta and sewage accommodate contradicting routine behaviours to cater for needs of residents and farmers. For example, when mothers pray wearing soiled clothing, and in the use of wastewater as fertiliser for food production. The excreta-related practices are compatible with good hygienic behaviour as outlined by WHO Guidelines, except for children who are allowed to defecate anywhere. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. The effect of recirculating aquaculture systems on the concentrations of heavy metals in culture water and tissues of Nile tilapia Oreochromis niloticus

    NARCIS (Netherlands)

    Martins, C.I.; Eding, E.H.; Verreth, J.A.J.

    2011-01-01

    To date, farming fish in recirculating aquaculture systems (RAS) is one of the most environmentally friendly ways of producing fish. However, with the trend towards intensification, and consequently decrease in water exchange rates, these systems may accumulate substances, such as heavy metals, in

  5. Recirculation over complex terrain

    Science.gov (United States)

    Kutter, Eric; Yi, Chuixiang; Hendrey, George; Liu, Heping; Eaton, Timothy; Ni-Meister, Wenge

    2017-06-01

    This study generated eddy covariance data to investigate atmospheric dynamics leeward of a small, forested hillside in upstate New York. The causes and effects of recirculation eddies were examined to support the larger goal of improving measurement of the exchange of energy, moisture, and trace gases between the terrestrial biosphere and the atmosphere over complex terrain. Sensors operated at five different altitudes on two separate towers—one at the top of the hill and one down the slope to the east—for approximately 8 weeks in the spring of 2013. During the experiment, the vertical potential temperature gradient was found to be the primary factor for determining whether winds interacting with the terrain features caused a recirculating eddy leeward of the hill. The study found evidence that the recirculation influenced carbon dioxide flux and caused the air column to be vertically well mixed.

  6. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, cultur...... for determining bacterial activity might provide a means for future monitoring and assessment of microbial water quality in aquaculture farming systems......Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

  7. Device for controlling a recirculation flow in a reactor

    International Nuclear Information System (INIS)

    Shida, Toichi; Tohei, Kazushige; Hirose, Masao; Nakamura, Hideo.

    1976-01-01

    Object: To provide an emergency cut-off valve in a recirculation system in a reactor to control the recirculation at the time of turbine trip or load cut-off, thereby relieving excessive increase in heat output of fuel. Structure: A recirculation pump is driven through a recirculation pump motor by an AC generator, which is driven by a driving motor through a fluid coupling, so that reactor water passes the emergency cut-off valve and recirculation flow stop valve and then passes a jet pump into the core. At the time of turbine trip or load cut-off, the emergency cut-off valve is closed by a hydraulic circuit, whereby core flow is merely decreased by 20 to 30% in a short period of time to restrain excessive increase in heat output. (Yoshino, Y.)

  8. Comparative analysis of the simulation of the instantaneous closing of the discharge valve of a recirculation loop of a BWR with a model of recirculation loop with 2 jet pumps and another model with 20 jet pumps using RELAP5/SCDAPSIM Mod. 3.4; Analisis comparativo de la simulacion del cierre instantaneo de la valvula de descarga de un lazo de recirculacion de un BWR con un modelo de lazo de recirculacion con 2 bombas chorro y un modelo con 20 bombas chorro empleando RELAP5/SCDAPSIM Mod. 3.4

    Energy Technology Data Exchange (ETDEWEB)

    Araiza M, E.; Ortiz V, J.; Martinez C, E.; Amador G, R.; Castillo D, R., E-mail: enrique.araiza@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    This work presents the results of the simulation of the instantaneous closing of the water hammer, of a recirculation loop using two different arrangements in the loops. One of these arrangements corresponds to the traditional model that uses only two jet pumps to simulate the twenty pumps of the two recirculation loops of a BWR. The second nodalization models each of the ten jet pumps of each recirculation loop. The results obtained from the execution of both models are compared, using important variables such as pressures and mass costs for the same components of both models. In addition, the maximum pressure value generated on the pipe located upstream of the water hammer, relative to the design pressure of the pipe, is compared for each arrangement. (Author)

  9. High ratio recirculating gas compressor

    Science.gov (United States)

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  10. Preoperational test report, recirculation condenser cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  11. Preoperational test report, recirculation condenser cooling systems

    International Nuclear Information System (INIS)

    Clifton, F.T.

    1997-01-01

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System

  12. Algal culture studies related to a Closed Ecological Life Support System (CELSS)

    Science.gov (United States)

    Radmer, R.; Behrens, P.; Fernandez, E.; Ollinger, O.; Howell, C.; Venables, A.; Huggins, D.; Gladue, R.

    1984-01-01

    In many respects, algae would be the ideal plant component for a biologically based controlled life support system, since they are eminently suited to the closely coupled functions of atmosphere regeneration and food production. Scenedesmus obliquus and Spirulina platensis were grown in three continuous culture apparatuses. Culture vessels their operation and relative merits are described. Both light and nitrogen utilization efficiency are examined. Long term culture issues are detailed and a discussion of a plasmid search in Spirulina is included.

  13. Recirculation system for nuclear reactors

    International Nuclear Information System (INIS)

    Braun, H. E.; Dollard, W. J.; Tower, S. N.

    1980-01-01

    A recirculation system for use in pressurized water nuclear reactors to increase the output temperature of the reactor coolant, thereby achieving a significant improvement in plant efficiency without exceeding current core design limits. A portion of the hot outlet coolant is recirculated to the inlets of the peripheral fuel assemblies which operate at relatively low power levels. The outlet temperature from these peripheral fuel assemblies is increased to a temperature above that of the average core outlet. The recirculation system uses external pumps and introduces the hot recirculation coolant to the free space between the core barrel and the core baffle, where it flows downward and inward to the inlets of the peripheral fuel assemblies. In the unlikely event of a loss of coolant accident, the recirculation system flow path through the free space and to the inlets of the fuel assemblies is utilized for the injection of emergency coolant to the lower vessel and core. During emergency coolant injection, the emergency coolant is prevented from bypassing the core through the recirculation system by check valves inserted into the recirculation system piping

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

    OpenAIRE

    Solmaz Aslanzadeh; Karthik Rajendran; Azam Jeihanipour; Mohammad J. Taherzadeh

    2013-01-01

    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; st...

  15. Technology development for recirculating heavy-ion accelerators

    International Nuclear Information System (INIS)

    Newton, M.A.; Kirbie, H.C.

    1993-01-01

    The open-quotes recirculator,close quotes a recirculating heavy-ion accelerator has been identified as a promising approach for an inertial fusion driver. System studies have been conducted to evaluate the recirculator on the basis of feasibility and cost. The recirculator has been shown to have significant cost advantages over other potential driver schemes, but some of the performance requirements exceed the capabilities of present technology. The system studies identified the high leverage areas where advances in technology will significantly impact the cost and performance of a recirculator. One of the high leverage areas is the modulator system which generates the acceleration potentials in the induction cells. The modulator system must be capable of generating the acceleration potentials at peak repetition rates in excess of 100 kHz with variable pulse widths. LLNL is developing a modulator technology capable of driving induction cells using the latest in solid state MOSFET technology. A small scale modulator has been built and tested to prove the concept and the next version is presently being designed. The objective is to demonstrate a modulator operating at 5 kV, 1 kA, with 0.2--1 μs pulse widths while driving an induction cell at >100 kHz within the next year. This paper describes the recirculator, the technology requirements necessary to implement it and the modulator system development that is being pursued to meet these requirements

  16. Low Load Model of a Once-through Boiler with Recirculation

    DEFF Research Database (Denmark)

    Trangbæk, Klaus

    2006-01-01

    A dynamic simulation model of a once-through boiler in low to medium load is developed. When the system is in low load, water from the evaporator is recirculated through a bottle. This recirculation system is included in the model, which is then shown to fit closed-loop data from a real plant...

  17. Unit process engineering for water quality control and biosecurity in marine water recirculating systems

    Science.gov (United States)

    High-intensity systems that treat and recirculate water must maintain a culture environment that can sustain near optimum fish health and growth at the design carrying capacity. Water recirculating systems that use centralized treatment systems can benefit from the economies of scale to decrease th...

  18. Small doses, big troubles: modeling growth dynamics of organisms affecting microalgal production cultures in closed photobioreactors.

    Science.gov (United States)

    Forehead, Hugh I; O'Kelly, Charles J

    2013-02-01

    The destruction of mass cultures of microalgae by biological contamination of culture medium is a pervasive and expensive problem, in industry and research. A mathematical model has been formulated that attempts to explain contaminant growth dynamics in closed photobioreactors (PBRs). The model simulates an initial growth phase without PBR dilution, followed by a production phase in which culture is intermittently removed. Contaminants can be introduced at any of these stages. The model shows how exponential growth from low initial inocula can lead to "explosive" growth in the population of contaminants, appearing days to weeks after inoculation. Principal influences are contaminant growth rate, PBR dilution rate, and the size of initial contaminant inoculum. Predictions corresponded closely with observed behavior of two contaminants, Uronema sp. and Neoparamoeba sp., found in operating PBRs. A simple, cheap and effective protocol was developed for short-term prediction of contamination in PBRs, using microscopy and archived samples. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Effect of gas recirculation intensity and various temperatures on ...

    African Journals Online (AJOL)

    The influence of mixing H2/CO2 gas recirculation on the performance of hydrogenotrophic methanogens activity in continuous culture was studied at 37 and 20°C. Chemostat fermentation was used at laboratory scale to determine the bioconversion rate of H2/CO2 mixture gas to methane under different mixing rates.

  20. A novel closed cell culture device for fabrication of corneal epithelial cell sheets.

    Science.gov (United States)

    Nakajima, Ryota; Kobayashi, Toyoshige; Moriya, Noboru; Mizutani, Manabu; Kan, Kazutoshi; Nozaki, Takayuki; Saitoh, Kazuo; Yamato, Masayuki; Okano, Teruo; Takeda, Shizu

    2015-11-01

    Automation technology for cell sheet-based tissue engineering would need to optimize the cell sheet fabrication process, stabilize cell sheet quality and reduce biological contamination risks. Biological contamination must be avoided in clinical settings. A closed culture system provides a solution for this. In the present study, we developed a closed culture device called a cell cartridge, to be used in a closed cell culture system for fabricating corneal epithelial cell sheets. Rabbit limbal epithelial cells were cultured on the surface of a porous membrane with 3T3 feeder cells, which are separate from the epithelial cells in the cell cartridges and in the cell-culture inserts as a control. To fabricate the stratified cell sheets, five different thicknesses of the membranes which were welded to the cell cartridge, were examined. Multilayered corneal epithelial cell sheets were fabricated in cell cartridges that were welded to a 25 µm-thick gas-permeable membrane, which was similar to the results with the cell-culture inserts. However, stratification of corneal epithelial cell sheets did not occur with cell cartridges that were welded to 100-300 µm-thick gas-permeable membranes. The fabricated cell sheets were evaluated by histological analyses to examine the expression of corneal epithelial-specific markers. Immunohistochemical analyses showed that a putative stem cell marker, p63, a corneal epithelial differentiation maker, CK3, and a barrier function marker, Claudin-1, were expressed in the appropriate position in the cell sheets. These results suggest that the cell cartridge is effective for fabricating corneal epithelial cell sheets. Copyright © 2012 John Wiley & Sons, Ltd.

  1. Incorporating the cultural diversity of family and close relationships into the study of health.

    Science.gov (United States)

    Campos, Belinda; Kim, Heejung S

    2017-09-01

    Relationships are at the center of the human social environment, and their quality and longevity are now recognized to have particular relevance for health. The goal of this article is to bring attention to the role of culture in how relationships, particularly close relationships and family relationships, influence health. To this end, 2 contexts that are characterized by 2 distinct forms of cultural collectivism (East Asian and Latino) are spotlighted to highlight the unique patterns that underlie broader cultural categories (e.g., collectivism). In addition, related research on other understudied cultures and nonethnic or nonnational forms of culture (e.g., social class, religion) is also discussed. The review centers on social support, a key pathway through which relationships shape psychological and physical health, as the psychological process that has received the most empirical attention in this area. Overall, it is clear that new and more systematic approaches are needed to generate a more comprehensive, novel, and inclusive understanding of the role of culture in relationship processes that shape health. Three recommendations are offered for researchers and professionals to generate and incorporate knowledge of culture-specific relationship processes into their understanding of health. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. Fractal solutions of recirculation tubular chemical reactors

    International Nuclear Information System (INIS)

    Berezowski, Marek

    2003-01-01

    Three kinds of fractal solutions of model of recirculation non-adiabatic tubular chemical reactors are presented. The first kind concerns the structure of Feigenbaum's diagram on the limit of chaos. The second kind and the third one concern the effect of initial conditions on the dynamic solutions of models. In the course of computations two types of recirculation were considered, viz. the recirculation of mass (return of a part of products' stream) and recirculation of heat (heat exchange in the external heat exchanger)

  3. In situ corrosion potential measurements in the main recirculation system of the Barsebaeck 1 BWR

    International Nuclear Information System (INIS)

    Molander, A.; Karlberg, G.

    1994-01-01

    In situ corrosion potential measurements are performed in one of the main recirculation loops of the Barsebaeck 1 BWR. The installation was performed close to a stainless steel ring where crack indications have earlier been obtained by nondestructive testing. Simultaneous measurements were performed in the residual heat removal system and in a side-stream system. The purpose of the measurements was to investigate any differences in the corrosion potential of stainless steel between the monitoring point in the main recirculation system and the residual heat removal system, which has earlier been used for hydrogen dosage surveillance. The results show that the corrosion potential in the main recirculation system and the residual heat removal system can differ. The differences depend on the hydrogen doserate and the main recirculation flow. Under certain circumstances the corrosion potential in the main recirculation system was up to two hundred millivolts higher in the main recirculation system compared to the residual heat removal system. For future hydrogen water chemistry surveillance it is recommended to perform the corrosion potential monitoring in the main recirculation system. Measurements in the residual heat removal system are recommended for backup reasons

  4. Shame closely tracks the threat of devaluation by others, even across cultures.

    Science.gov (United States)

    Sznycer, Daniel; Tooby, John; Cosmides, Leda; Porat, Roni; Shalvi, Shaul; Halperin, Eran

    2016-03-08

    We test the theory that shame evolved as a defense against being devalued by others. By hypothesis, shame is a neurocomputational program tailored by selection to orchestrate cognition, motivation, physiology, and behavior in the service of: (i) deterring the individual from making choices where the prospective costs of devaluation exceed the benefits, (ii) preventing negative information about the self from reaching others, and (iii) minimizing the adverse effects of devaluation when it occurs. Because the unnecessary activation of a defense is costly, the shame system should estimate the magnitude of the devaluative threat and use those estimates to cost-effectively calibrate its activation: Traits or actions that elicit more negative evaluations from others should elicit more shame. As predicted, shame closely tracks the threat of devaluation in the United States (r = .69), India (r = .79), and Israel (r = .67). Moreover, shame in each country strongly tracks devaluation in the others, suggesting that shame and devaluation are informed by a common species-wide logic of social valuation. The shame-devaluation link is also specific: Sadness and anxiety-emotions that coactivate with shame-fail to track devaluation. To our knowledge, this constitutes the first empirical demonstration of a close, specific match between shame and devaluation within and across cultures.

  5. Biorremediación de los efluentes de cultivo del camarón Litopenaeus vannamei (Boone, 1931 utilizando tapetes microbianos en un sistema de recirculación Bioremediacion of effluents ones of the culture of Litopenaeus vannamei (Boone, 1931 using microbial mats in a recirculating system

    Directory of Open Access Journals (Sweden)

    Carlos Lezama-Cervantes

    2010-01-01

    Full Text Available Se desarrolló un sistema de recirculación (SR integrando el cultivo del camarón con tapetes microbianos buscando mitigar los impactos ambientales de los subproductos del cultivo del camarón y avanzar hacia la biorremediación del agua de cultivo. Los consorcios microbianos obtenidos de ambientes naturales (TaM estuvieron constituidos por bacterias (55,6%, cianófitas (18,4%, diatomeas (9%, nemátodos (5,6% y clorófitas (1,4%, entre los grupos taxonómicos principales. La remoción de nutrientes y sólidos se evaluó en un SR (2 ciclos/hora conteniendo (n = 3 60 y 120 ind m-2 de Litopenaeus vannamei. Los resultados demostraron que los TaM redujeron los niveles de nitrógeno amoniacal por encima del 71% diariamente; la demanda bioquímica de oxígeno (DBO5 se redujo más de 68% y los sólidos suspendidos (SST hasta en 62% al compararse con los sistemas control (p 0,05. El agua bio-remediada tiene un efecto positivo en el cultivo de Litopenaeus vannamei, y promueve el crecimiento y sobrevivencia en presencia de TaM en el SR.We developed a recirculating system integrating shrimp culture with microbial mats aiming to mitigate the environmental impacts of by-products from shrimp culture and to advance toward the bioremediation of the shrimp culture water. The microbial consortia collected from natural environments (TaM was constituted by bacteria (55.6%, Cyanophyte (18.4%, diatoms (9%, nematods (5.6% and Chlorophyte algae (1.4% among the major taxonomic groups. The removal of nutrients and solids by these mats was assessed in a recirculating system (2 cycles/hour (n = 3 containing 60 and 120 ind m-2 of Litopenaeus vannamei. Results showed that the microbial mat reduces daily up to 71% of ammonia nitrogen, decreases around 68% of the biochemical oxygen demand (DBO5 and up to 62% of suspended solids (SST when comparing to the control systems (p 0.05. The Bioremediated culture water had a positive effect on the culture of Litopenaeus vannamei, and

  6. BWR series pump recirculation system

    International Nuclear Information System (INIS)

    Dillmann, C.W.

    1992-01-01

    This patent describes a recirculation system for driving reactor coolant water contained in an annular downcomer defined between a boiling water reactor vessel and a reactor core spaced radially inwardly therefrom. It comprises a plurality of circumferentially spaced second pumps disposed in the downcomer, each including an inlet for receiving from the downcomer a portion of the coolant water as pump inlet flow, and an outlet for discharging the pump inlet flow pressurized in the second pump as pump outlet flow; and means for increasing pressure of the pump inlet flow at the pump inlet including a first pump disposed in series flow with the second pump for first receiving the pump inlet flow from the downcomer and discharging to the second pump inlet flow pressurized in the first pump

  7. Na+ Recirculation and Isosmotic Transport

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Møbjerg, N

    2006-01-01

    of the absorbate. Mathematical modeling reproducing bioelectric and hydrosmotic properties of small intestine and proximal tubule, respectively, predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability...... external baths. Hyperosmolarity of lis is governed by the hydraulic permeability of the apical plasma membrane and tight junction with 6-7 mOsm in small intestine and transport demands a Na(+) recirculation of 50-70% in small intestine but might be barely...... measurable in proximal tubule. The model fails to reproduce a certain type of observations: The reduced volume absorption at transepithelial osmotic equilibrium in AQP1 knockout mice, and the stimulated water absorption by gallbladder in diluted external solutions. Thus, it indicates cellular regulation...

  8. Evaluation of urogenital Chlamydia trachomatis infections by cell culture and the polymerase chain reaction using a closed system

    DEFF Research Database (Denmark)

    Østergaard, Lars; Traulsen, J; Birkelund, Svend

    1991-01-01

    the two test systems were compared, the overall sensitivity of the polymerase chain reaction was 96% and the specificity 94% when compared to the cell culture technique. By use of a closed system for DNA extraction and sample transfer for the polymerase chain reaction, contamination of the samples......Two hundred and fifty-four specimens from males and females consulting a clinic for sexually transmitted diseases were analyzed for genital Chlamydia trachomatis infection. Each clinical sample was tested by the cell culture technique and the polymerase chain reaction using a closed system. When...... not detect Chlamydia trachomatis after sufficient antibiotic treatment of the chlamydial infections....

  9. Evaluation of urogenital Chlamydia trachomatis infections by cell culture and the polymerase chain reaction using a closed system

    DEFF Research Database (Denmark)

    Østergaard, Lars; Traulsen, J; Birkelund, Svend

    1993-01-01

    the two test systems were compared, the overall sensitivity of the polymerase chain reaction was 96% and the specificity 94% when compared to the cell culture technique. By use of a closed system for DNA extraction and sample transfer for the polymerase chain reaction, contamination of the samples......Two hundred and fifty-four specimens from males and females consulting a clinic for sexually transmitted diseases were analyzed for genital Chlamydia trachomatis infection. Each clinical sample was tested by the cell culture technique and the polymerase chain reaction using a closed system. When...... not detect Chlamydia trachomatis after sufficient antibiotic treatment of the chlamydial infections....

  10. A Study on the Adverse Effect of AOVs in AFWS Recirculation Paths on Plant Safety

    Energy Technology Data Exchange (ETDEWEB)

    Huong, Ho Thi Thanh [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Chung, Dae-Wook [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2014-10-15

    Auxiliary feedwater system (AFWS) recirculation flow paths adopted air operated valves (AOVs) which could fail close on loss of instrument air (LOIA) event. So the AOVs and recirculation paths are closed on LOIA event, which could result in Auxiliary feedwater (AFW) pump(s) damage, which contributes greatly to core damage frequency (CDF).. On February 2002, the USNRC issued an inspection finding related to potential common cause failure of AOVs in AFWS recirculation flow paths on loss of instrument air system in Point Beach nuclear power plant (Pt. Beach). The AOVs have been removed from AFWS recirculation paths in the design of Korea standard nuclear power plant (KSNP). So, there is no possibility of above mentioned failure event in KSNP. It would be beneficial to evaluate the significance of adverse effect of AOVs in AFWS recirculation paths to realize the importance of maintaining AFWS recirculation paths always open. In this study, the AFWS modeling of Ulchin unit 3 and 4 was modified to model the AOVs in AFW recirculation flow paths to evaluate the change in CDF, which is caused by the adverse effect of AOV with operation mode of 'fails close' on LOIA event. It is concluded that the existence of AOV with 'fail close' design in AFWS MDP recirculation paths results in CDF increase of 131%, which is significant adverse effect on plant safety.. In this regard, the improved Westinghouse design and KSNP design had removed the AOVs from AFWS MDP recirculation paths. However, a couple of units with old Westinghouse design, Kori 1 and 2, still have AOVs in AFWS MDP recirculation paths and throttle back operation of AFWS is in effect. Although those AOVs adopt 'fail open' design to prevent above mentioned inadvertent closure, considering the big increase in CDF, there still exists considerable risk from the possibility of 'failure to open' during this throttle back operation. Therefore, it is strongly recommended that any

  11. A recirculating stream aquarium for ecological studies.

    Science.gov (United States)

    Gordon H. Reeves; Fred H. Everest; Carl E. McLemore

    1983-01-01

    Investigations of the ecological behavior of fishes often require studies in both natural and artificial stream environments. We describe a large, recirculating stream aquarium and its controls, constructed for ecological studies at the Forestry Sciences Laboratory in Corvallis.

  12. Personal value preferences, group identifications, and cultural practices of Palestinian Israelis working in close contact with Jewish Israelis.

    Science.gov (United States)

    Tartakovsky, Eugene; Abu Kheit, Ayat

    2017-01-01

    The present study investigates the connection between personal value preferences, group identifications, and cultural practices among Palestinian Israelis working in close contact with the Jewish population in Israel. One hundred twenty-two Palestinian Israelis participated in the study. The participants were employed in different professional positions in the Tel Aviv Metropolitan area and were recruited to the study using the snowball technique. A stronger national identification was associated with a higher preference for the security and conformity values, and a lower preference for the humility values. A stronger ethnic identification was associated with a lower preference for the security, power, and stimulation values. Group identifications mediated the connection between personal value preferences and cultural practices. A longer time working in close contact with the majority group and less frequent visits home were associated with a greater adherence to the majority group's cultural practices but not with adherence to the ethnic group's practices and not with the group identifications.

  13. Physical and chemical quality of water in closed recirculation system during the cultivation of Nile tilapia juvenilesQualidade física e química da água em sistema fechado de recirculação durante o cultivo de juvenis de tilápia-do-Nilo

    Directory of Open Access Journals (Sweden)

    Nilton Garcia Marengoni

    2013-05-01

    Full Text Available The study aimed to evaluate the effect of the filter and time of cultivation of Nile tilapia juveniles in water quality in closed recirculating system. There were used 1,350 fingerlings of Nile tilapia (Oreochromis niloticus in a randomized block experimental design and split-plot time with twelve treatments and three replicates. The treatments were a combination of two local of water harvesting (before the mechanical filter and after the biological filter and six periods of cultivation (14, 28, 42, 56, 70 and 84 days, in a split plot arrangement. The water temperature, dissolved oxygen, oxygen saturation, electrical conductivity and pH did not affect the development of the fish in closed recirculating water. It was observed that the water collected after the biological filter had better physical and chemical quality than that collected before the mechanical filter. The dissolved oxygen levels in the water after the biological filter were higher (PO trabalho teve por objetivo avaliar o efeito do filtro e do tempo de cultivo de alevinos de tilápia-do-Nilo sobre a qualidade de água do sistema de recirculação fechado. Foram utilizados 1.350 alevinos de tilápia-do-Nilo (Oreochromis niloticus em delineamento experimental de blocos casualizados e esquema de parcelas subdivididas no tempo, com doze tratamentos e três repetições. Os tratamentos foram constituídos pela combinação de dois locais de coleta de água (antes do filtro mecânico e após o filtro biológico e de seis tempos de cultivo (14, 28, 42, 56, 70 e 84 dias, em esquema de parcelas subdivididas. A temperatura, oxigênio dissolvido, saturação de oxigênio, condutividade elétrica e pH não afetaram a desenvolvimento dos peixes em sistema fechado de recirculação de água. Observou-se que a água coletada após o filtro biológico apresentou melhor qualidade física e química que a coletada antes do filtro mecânico. Os níveis de oxigênio dissolvido na água após o filtro

  14. Microbial populations causing off-flavour in recirculated aquaculture systems

    DEFF Research Database (Denmark)

    Lukassen, Mie Bech; Nielsen, Jeppe Lund; Schramm, Edward

    and are found in at least six phylogenetic groups covering 0.1% of the total community with only a minor fraction being culturable. Quantification of geoA within recirculated aquaculture systems reveals that geosmin-producing bacteria are more abundant in the water treatment compartments compared to the water......Microbial production of geosmin, a secondary metabolite with an earthy off-flavour is a serious economic problem in wine production, drinking water and aquaculture. Geosmin is produced by a small group of bacteria all harboring the geosmin synthetase gene (geoA). Sequencing and analyzing...

  15. A recirculating hydroponic system for studying peanut (Arachis hypogaea L.)

    Science.gov (United States)

    Mackowiak, C. L.; Wheeler, R. M.; Stutte, G. W.; Yorio, N. C.; Ruffe, L. M.; Sager, J. C. (Principal Investigator)

    1998-01-01

    Peanut (Arachis hypogaea L.) plants were grown hydroponically, using continuously recirculating nutrient solution. Two culture tray designs were tested; one tray design used only nutrient solution, while the other used a sphagnum-filled pod development compartment just beneath the cover and above the nutrient solution. Both trays were fitted with slotted covers to allow developing gynophores to reach the root zone. Peanut seed yields averaged 350 gm-2 dry mass, regardless of tray design, suggesting that substrate is not required for hydroponic peanut production.

  16. BWR recirculation pump diagnostic expert system

    International Nuclear Information System (INIS)

    Chiang, S.C.; Morimoto, C.N.; Torres, M.R.

    2004-01-01

    At General Electric (GE), an on-line expert system to support maintenance decisions for BWR recirculation pumps for nuclear power plants has been developed. This diagnostic expert system is an interactive on-line system that furnishes diagnostic information concerning BWR recirculation pump operational problems. It effectively provides the recirculation pump diagnostic expertise in the plant control room continuously 24 hours a day. The expert system is interfaced to an on-line monitoring system, which uses existing plant sensors to acquire non-safety related data in real time. The expert system correlates and evaluates process data and vibration data by applying expert rules to determine the condition of a BWR recirculation pump system by applying knowledge based rules. Any diagnosis will be automatically displayed, indicating which pump may have a problem, the category of the problem, and the degree of concern expressed by the validity index and color hierarchy. The rules incorporate the expert knowledge from various technical sources such as plant experience, engineering principles, and published reports. These rules are installed in IF-THEN formats and the resulting truth values are also expressed in fuzzy terms and a certainty factor called a validity index. This GE Recirculation Pump Expert System uses industry-standard software, hardware, and network access to provide flexible interfaces with other possible data acquisition systems. Gensym G2 Real-Time Expert System is used for the expert shell and provides the graphical user interface, knowledge base, and inference engine capabilities. (author)

  17. NGL recovery increase through natural gasoline recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rivas M., M.; Bracho, J.L.; Murray, J. [Lagoven S.A., Maracaibo (Venezuela). Western Div.

    1997-12-31

    Given that the gas being processed in the compression plants Tia Juana 2 (PCTJ-2) and Tia Juana 3 (PCTJ-3) of Lagoven, S.A., an operating affiliate of Petroleos de Venezuela, S.A. has become learner through time, current production of natural gas liquids (NGL) and plant efficiency are significantly lower, compared to design and first obtained values. In this sense and aimed at increasing propane production, an optimization study on condensate stream recirculation and absorber installation was carried out to affect the process equilibrium constants thereby obtaining deeper extraction. Recirculation streams options were recirculation of natural gasoline obtained from the downstream fractionation process and recirculation of a conditioned, unfractionated, deethanized condensate stream. From the study, the natural gasoline recirculation scheme was determined to be the most efficient NGL recovery process. Accordingly, Lagoven, S.A. has undertaken a project to carry out this optimization scheme in PCTJ-2 and PCTJ-3. Construction stages are currently underway with completion scheduled at the end of 1997.

  18. Closed-system 'economic' models for psychiatric disorders: Western atomism and its culture-bound syndromes.

    Science.gov (United States)

    Wallace, Rodrick

    2015-08-01

    The stabilization of human cognition via feedback from embedding social and cultural contexts is a dynamic process deeply intertwined with it, constituting, in a sense, the riverbanks directing the flow of a stream of generalized consciousness at different scales: Cultural norms and social interaction are synergistic with individual and group cognition and their disorders. A canonical failure mode in atomistic cultures is found to be a 'ground state' collapse well represented by atomistic models of economic interaction that are increasingly characterized as divorced from reality by heterodox economists. That is, high rates of psychopathic and antisocial personality disorder and obsessive compulsive disorder emerge as culture-bound syndromes particular to Western or Westernizing societies, or to those undergoing social disintegration.

  19. Effects of outdoor cultures on the growth and lipid production of Phaeodactylum tricornutum using closed photobioreactors.

    Science.gov (United States)

    Santos-Ballardo, David U; Rendón-Unceta, María Del Carmen; Rossi, Sergio; Vázquez-Gómez, Rosa; Hernández-Verdugo, Sergio; Valdez-Ortiz, Angel

    2016-08-01

    One of the principal challenges for large scale production of microalgae is the high costs of biomass production. Aiming for minimize this problem, microalgal biodiesel production should focus on outdoors cultures, using available solar light and allowing lower energy cost process. Testing species that proved to be common and easy to culture may be a good approach in this process. The present work reports indoor-outdoor cultures of Phaeodactylum tricornutum using different bioreactors types, using cell growth, biochemical composition, and the profiles of the fatty acids produced as the parameters to test the optimization processes. The results show that the use of outdoor cultures is a good choice to obtain P. tricornutum biomass with a good potential for biodiesel production. The microalgae produced reached better growth efficiency, major lipid content and showed an increment in the percentage of saturated fatty acids (required on the biodiesel production) respect indoor cultures. These results are important to show the relevance of using outdoor cultures as a way to improve the efficiency and the energetic balance of the biodiesel production with P. tricornutum algae.

  20. Cleaning and recirculation of perfluorohexane ($C_{6} F_{14}$) in the STAR-RICH detector

    CERN Document Server

    Andrés, Yu; Cozza, D; Davenport, M; De Cataldo, G; Dell'Olio, L; Di Bari, D; Di Mauro, A; Dunlop, J C; Finch, E; Fraissard, Daniel; Franco, A; Gans, J; Ghidini, B; Harris, J W; Horsley, M; Kunde, G J; Lasiuk, B; Lesenechal, Y; Majka, R D; Martinengo, P; Morsch, Andreas; Nappi, E; Paic, G; Piuz, François; Posa, F; Raynaud, J; Salur, S; Sandweiss, J; Santiard, Jean-Claude; Satinover, J; Schyns, E M; Smirnov, N; Van Beelen, J; Williams, T D; Xu, Z

    2002-01-01

    A RICH detector with a CsI photo-cathode and liquid perfluorohexane radiator has been installed in the STAR experiment at RHIC. The liquid is continuously cleaned and distributed to a quartz containment vessel within the detector by a closed recirculation system. A VUV spectrometer is connected to the system which monitors the optical transparency of the liquid. This measurement provides one of the pieces of information necessary to model the number of Cherenkov photons which reach the pad plane. A description of the liquid recirculation system and the cleaning procedure for the liquid as well as the spectrometer is presented along with results of their performance. (23 refs).

  1. 76 FR 63985 - Notice of Closed Meeting (With Open Session) of the Cultural Property Advisory Committee

    Science.gov (United States)

    2011-10-14

    ... orientation (closed session) for new members as well as ethics and security briefings. If you wish to make an... will not be edited to remove any identifying or contact information, the Department of State cautions... persons that the Department of State will not edit their comments to remove any identifying or contact...

  2. Inhibition Underlies the Effect of High Need for Closure on Cultural Closed-Mindedness under Mortality Salience

    Directory of Open Access Journals (Sweden)

    Dmitrij Agroskin

    2016-10-01

    Full Text Available The hypothesis that people respond to reminders of mortality with closed-minded, ethnocentric attitudes has received extensive empirical support, largely from research in the Terror Management theory tradition. However, the basic motivational and neural processes that underlie this effect remain largely hypothetical. According to recent neuropsychological theorizing, mortality salience (MS effects on cultural closed-mindedness may be mediated by activity in the behavioral inhibition system (BIS, which leads to passive avoidance and decreased approach motivation. This should be especially true for people motivated to avoid unfamiliar and potentially threatening stimuli as reflected in a high need for closure (NFC. In two studies involving moderated mediation analyses, people high on trait NFC responded to MS with increased BIS activity (as indicated by EEG and the line bisection task, which is characteristic of inhibited approach motivation. BIS activity, in turn, predicted a reluctance to explore foreign cultures (Study 1 and generalized ethnocentric attitudes (Study 2. In a third study, inhibition was induced directly and caused an increase in ethnocentrism for people high on NFC. Moreover, the effect of the inhibition manipulation × NCF interaction on ethnocentrism was explained by increases in BIS-related affect (i.e., anxious inhibition at high NFC. To our knowledge, this research is the first to establish an empirical link between very basic, neurally-instantiated inhibitory processes and rather complex, higher-order manifestations of intergroup negativity. Our findings contribute to a fuller understanding of the cultural worldview defense phenomenon by illuminating the motivational underpinnings of cultural closed-mindedness in the wake of existential threat.

  3. Anaerobic degradation of dairy wastewater in intermittent UASB reactors: influence of effluent recirculation.

    Science.gov (United States)

    Couras, C S; Louros, V L; Gameiro, T; Alves, N; Silva, A; Capela, M I; Arroja, L M; Nadais, H

    2015-01-01

    This work studied the influence of effluent recirculation upon the kinetics of anaerobic degradation of dairy wastewater in the feedless phase of intermittent upflow anaerobic sludge bed (UASB) reactors. Several laboratory-scale tests were performed with different organic loads in closed circuit UASB reactors inoculated with adapted flocculent sludge. The data obtained were used for determination of specific substrate removal rates and specific methane production rates, and adjusted to kinetic models. A high initial substrate removal was observed in all tests due to adsorption of organic matter onto the anaerobic biomass which was not accompanied by biological substrate degradation as measured by methane production. Initial methane production rate was about 45% of initial soluble and colloidal substrate removal rate. This discrepancy between methane production rate and substrate removal rate was observed mainly on the first day of all experiments and was attenuated on the second day, suggesting that the feedless period of intermittent UASB reactors treating dairy wastewater should be longer than one day. Effluent recirculation expressively raised the rate of removal of soluble and colloidal substrate and methane productivity, as compared with results for similar assays in batch reactors without recirculation. The observed bed expansion was due to the biogas production and the application of effluent recirculation led to a sludge bed contraction after all the substrates were degraded. The settleability of the anaerobic sludge improved by the introduction of effluent recirculation this effect being more pronounced for the higher loads.

  4. 75 FR 52581 - Notice of Meeting and Closed Meeting of the Cultural Property Advisory Committee

    Science.gov (United States)

    2010-08-26

    ... Government of the Republic of Cyprus Concerning the Imposition of Import Restrictions on Pre-Classical and Classical Archaeological Objects and Byzantine Period Ecclesiastical and Ritual Ethnological Material, and... Pre-Columbian Cultures and Certain Ethnological Material from the Colonial Period of Colombia [Docket...

  5. Sodium recirculation and isotonic transport in toad small intestine

    DEFF Research Database (Denmark)

    Nedergaard, Signe Nielsen; Larsen, Erik Hviid; Ussing, Hans H.

    1999-01-01

    Small intestine; leaky epithelia; solute-coupled water transport; Na*O+ recirculation; lateral intercellular space; flux ratio analysi......Small intestine; leaky epithelia; solute-coupled water transport; Na*O+ recirculation; lateral intercellular space; flux ratio analysi...

  6. Recirculating sprayer for fiber-filled paints

    Science.gov (United States)

    Major, R. K.

    1980-01-01

    Recirculating paint sprayer applies spray of coarse filler in highly volatile solvent. Sprayer was developed for applying insulation material containing epxoy resin, glass fibers, and inert fillers suspended in chlorinated solvents. Sprayer resists abrasive action of fiberglass filler and chemical activity of solvent. Pump and position ensure more uniform pressure at spray gun without backpressure regulator, which tended to clog in old sprayer.

  7. Development of efficient recirculation system for Tilapia ...

    African Journals Online (AJOL)

    TUOYO

    2010-08-09

    Aug 9, 2010 ... In the current experiment, a recirculation system was built using low cost materials that are available locally and its performance was tested. The performance evaluation procedure was carried out in an aquaculture system in greenhouse with sex-reversed male Nile tilapia (Oreochromis niloticus) production ...

  8. Development of efficient recirculation system for Tilapia ...

    African Journals Online (AJOL)

    In the current experiment, a recirculation system was built using low cost materials that are available locally and its performance was tested. The performance evaluation procedure was carried out in an aquaculture system in greenhouse with sex-reversed male Nile tilapia (Oreochromis niloticus) production in Querétaro ...

  9. STUDIES REGARDING THE PRESENCE OF THE PATHOGENS BACTERIA INTO A RECIRCULATING SYSTEM OF BELUGA STURGEON INTENSIVE REARING

    Directory of Open Access Journals (Sweden)

    ANGELICA DOCAN

    2008-10-01

    Full Text Available Recirculating aquaculture offers good potential for successful fish farming since is often independent of environmental conditions. Maintaining healthy fish in a recirculating system involves establishing adequate dissolved oxygen levels, removal of solid wastes, and sufficient ammonia nitrification to assure optimal rearing conditions. Neglecting these, the fish immune system will depress, the facultative pathogen germs will be able to provoke important disease outbreaks into cultured biomass, as was happened in our recirculating pilot system. In this study are presented the pathological aspects registered to the beluga sturgeon of 1 year, reared into our recirculating pilot system, pathological aspects generated by a haemorrhagic bacterial septicaemia which was manifested in the conditions of low concentrations of DO. The disease was diagnosed to the affected fish through anatomopathological and clinical exam, haematological exam and microbiological exam.

  10. Up close and personal: lesbian sub-culture in the female factories of Van Diemen's Land.

    Science.gov (United States)

    Nolan, Bláthnaid

    2013-01-01

    This article focuses on how the sexuality of convict women transported in the first half of the nineteenth century to Van Diemen's Land (Tasmania) was monitored by the British establishment. A series of Victorian enquiries into the convict system were set up to report on the efficacy of transportation. I argue that the anxious discussion and ensuing policies used to observe, curtail, punish, and "correct" convict women's bodies reveal the processes by which Victorian gender, class, and race regimes were socially constructed. Further, the article argues that convict women used various tools of resistance and defiance, one of which was the formation of lesbian sub-cultures as the embodiment of sexual dissidence.

  11. The radon daughter radiation hazard in controlled recirculation systems

    International Nuclear Information System (INIS)

    Rolle, R.; Burton, R.C.

    1987-01-01

    In deep South African gold mines, controlled recirculation systems with air cooling are being used to an increasing extent to improve the thermal environment. Recirculation causes some air to reside in the working area for a longer time than would have occurred without recirculation. Since radon daughters grow spontaneously from radon there is some concern that, with the extended residence time, the potential radiation hazard could increase to an unacceptable level. This paper describes the results obtained from a theoretical model of a controlled recirculation system. Guidelines for the design of recirculation systems to control the radon daughter radiation, and to keep it within acceptable limits are provided. 3 refs., 5 figs

  12. 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.

  13. Re-circulating linac vacuum system

    International Nuclear Information System (INIS)

    Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

    2003-01-01

    The vacuum system for a proposed 2.5 GeV, 10ΜA recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10ΜA average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing

  14. Adaptive feedforward control of exhaust recirculation in large diesel engines

    DEFF Research Database (Denmark)

    Nielsen, Kræn Vodder; Blanke, Mogens; Eriksson, Lars

    2017-01-01

    Environmental concern has led the International Maritime Organization to restrict NO푥 emissions from marine diesel engines. Exhaust gas recirculation (EGR) systems have been introduced in order to comply to the new standards. Traditional fixed-gain feedback methods are not able to control the EGR...... is generalized to a class of first order Hammerstein systems with sensor delay and exponentially converging bounds of the control error are proven analytically. It is then shown how to apply the method to the EGR system of a two-stroke crosshead diesel engine. The controller is validated by closed loop...... system adequately in engine loading transients so alternative methods are needed. This paper presents the design, convergence proofs and experimental validation of an adaptive feedforward controller that significantly improves the performance in loading transients. First the control concept...

  15. Requirements for longitudinal HOM damping in superconducting recirculating linacs

    International Nuclear Information System (INIS)

    Bisognano, J.J.; Fripp, M.L.

    1989-01-01

    Transverse beam breakup provides the primary current limitation in the operation of superconducting recirculating linacs and requires the significant damping of transverse-deflecting higher order modes. The need to damp the coexisting longitudinal HOMs in these nominally isochronous machines, however, is not as clear. Isochronicity implies that energy variations induced by excitation of longitudinal modes do not translate directly into position and current modulations. Such modulations, if present, could enhance the initial excitation, effectively closing a potentially unstable feedback loop. Design optimization of cavity structures may suggest that no longitudinal damping be provided. On the other hand, easing of the isochronicity requirement may provide desired flexibility in lattice design. In this note, limits are placed on the requirements for longitudinal HOM damping and on the tolerances for isochronicity which are driven by possible longitudinal multipass phenomena. 2 refs., 1 fig

  16. Closed-looped in situ nano processing on a culturing cell using an inverted electron beam lithography system

    International Nuclear Information System (INIS)

    Hoshino, Takayuki; Mabuchi, Kunihiko

    2013-01-01

    Highlights: ► An electron beam lithography (EBL) was used as an in situ nano processing for a living cell. ► A synchronized optics was containing an inverted EBL and an optical microscope. ► This system visualized real-time images of the EB-induced nano processing. ► We demonstrated the nano processing for a culturing cell with 200–300 nm resolution. ► Our system would be able to provide high resolution display of virtual environments. -- Abstract: The beam profile of an electron beam (EB) can be focused onto less than a nanometer spot and scanned over a wide field with extremely high speed sweeping. Thus, EB is employed for nano scale lithography in applied physics research studies and in fabrication of semiconductors. We applied a scanning EB as a control system for a living cell membrane which is representative of large scale complex systems containing nanometer size components. First, we designed the opposed co-axial dual optics containing inverted electron beam lithography (I-EBL) system and a fluorescent optical microscope. This system could provide in situ nano processing for a culturing living cell on a 100-nm-thick SiN nanomembrane, which was placed between the I-EBL and the fluorescent optical microscope. Then we demonstrated the EB-induced chemical direct nano processing for a culturing cell with hundreds of nanometer resolution and visualized real-time images of the scanning spot of the EB-induced luminescent emission and chemical processing using a high sensitive camera mounted on the optical microscope. We concluded that our closed-loop in situ nano processing would be able to provide a nanometer resolution display of virtual molecule environments to study functional changes of bio-molecule systems

  17. Exhaust gas recirculation system for an internal combustion engine

    Science.gov (United States)

    Wu, Ko-Jen

    2013-05-21

    An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

  18. Preoperational test report, recirculation ventilation systems

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  19. Recent advances within intensive Recirculated Aquaculture System cultivation of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Jepsen, Per Meyer; Højgaard, Jacob Kring; Drillet, Guillaume

    2014-01-01

    and the nauplii can be feed to marine fish larvae. A restriction is that copepod cultures for producing eggs are after 30 years of research still not stable and in large enough scale for bulk production of eggs. Recently a unique copepod Recirculated Aquaculture System (RAS) at Roskilde University (Denmark......) was constructed as a part of the IMPAQ project “IMProvement of AQuaculture high quality fish fry production”. We present recent advance within RAS culture for copepods, and lesson learned from rearing the specie. Further we present physical and biological culture restrictions in terms of water quality (NH3...

  20. Development of cooling techniques for induction heating stress improvement of reactor recirculation inlet nozzle

    International Nuclear Information System (INIS)

    Takahashi, Shirou; Shiina, Kouji; Nihei, Kenichi; Kanno, Satoshi; Hayashi, Shoji; Ootaka, Minoru

    2007-01-01

    Induction heating stress improvement (IHSI) has been used in nuclear power plants to reduce residual stress in welded sections of pipes by generating temperature differences between the inner and outer surfaces of the pipes. The outer metal surface is heated by induction heating, and the inner surface is cooled by flowing water. However, it is difficult to obtain a sufficient temperature gradient in the places where the flow stagnates and the heat transfer cannot be enhanced. In the present study, we developed cooling techniques for a reactor recirculation inlet nozzle with a closed end and very narrow annular channel. Computational fluid dynamics (CFD) analyses, half-scale tests, and full-scale tests were conducted to investigate the flow and cooling characteristics. One million grids of a reactor recirculation inlet nozzle model were used for the CFD analysis. Detached eddy simulation (DES) was used as the turbulence model to evaluate the unsteady phenomena of the jet flow and temperature distribution. The experimental apparatuses used for the half-scale tests were made of acryl to visualize the flow, and heat transfer coefficients were measured at the welded portions. In the full-scale tests, the temperature differences between the inner and outer surface of the recirculation inlet nozzle were measured, and reduction of the residual stress was verified. It was confirmed that the jet flow moved up and down when to jet nozzles were arranged symmetrically. The turbulence due to self-sustained jet fluctuation was effective for uniform cooling in the reactor recirculation inlet nozzle. The flow did not stagnate around the welded portion. The heat transfer coefficients at the welded portion were evaluated using an equation with Reynolds and Nusselt numbers in half-scale tests. It was also verified in full scale tests that the temperature difference between the inner and outer surfaces of the recirculation inlet nozzle was approximately 490degC, which satisfied the

  1. Murine Cytomegalovirus Spreads by Dendritic Cell Recirculation

    Directory of Open Access Journals (Sweden)

    Helen E. Farrell

    2017-10-01

    Full Text Available Herpesviruses have coevolved with their hosts over hundreds of millions of years and exploit fundamental features of their biology. Cytomegaloviruses (CMVs colonize blood-borne myeloid cells, and it has been hypothesized that systemic dissemination arises from infected stem cells in bone marrow. However, poor CMV transfer by stem cell transplantation argues against this being the main reservoir. To identify alternative pathways for CMV spread, we tracked murine CMV (MCMV colonization after mucosal entry. We show that following intranasal MCMV infection, lung CD11c+ dendritic cells (DC migrated sequentially to lymph nodes (LN, blood, and then salivary glands. Replication-deficient virus followed the same route, and thus, DC infected peripherally traversed LN to enter the blood. Given that DC are thought to die locally following their arrival and integration into LN, recirculation into blood represents a new pathway. We examined host and viral factors that facilitated this LN traverse. We show that MCMV-infected DC exited LN by a distinct route to lymphocytes, entering high endothelial venules and bypassing the efferent lymph. LN exit required CD44 and the viral M33 chemokine receptor, without which infected DC accumulated in LN and systemic spread was greatly reduced. Taken together, our studies provide the first demonstration of virus-driven DC recirculation. As viruses follow host-defined pathways, high endothelial venules may normally allow DC to pass from LN back into blood.

  2. Cleaning and recirculation of perfluorohexane (C sub 6 F sub 1 sub 4) in the STAR-RICH detector

    CERN Document Server

    Andrés, Yu; Cozza, D; Davenport, M; De Cataldo, G; Dell-Olio, L; Di Bari, D; Di Mauro, A; Dunlop, J C; Finch, E; Fraissard, Daniel; Franco, A; Gans, J; Ghidini, B; Harris, J W; Horsley, M; Kunde, G J; Lasiuk, B; Lesenechal, Y; Majka, R D; Martinengo, P; Morsch, Andreas; Nappi, E; Paic, G; Piuz, François; Posa, F; Raynaud, J; Salur, S; Sandweiss, J; Santiard, Jean-Claude; Satinover, J; Schyns, E; Smirnov, N; Van Beelen, J; Williams, T D; Xu, Z

    2002-01-01

    A RICH detector with a CsI photo-cathode and liquid perfluorohexane radiator has been installed in the STAR experiment at RHIC. The liquid is continuously cleaned and distributed to a quartz containment vessel within the detector by a closed recirculation system. A VUV spectrometer is connected to the system which monitors the optical transparency of the liquid. This measurement provides one of the pieces of information necessary to model the number of Cherenkov photons which reach the pad plane. A description of the liquid recirculation system and the cleaning procedure for the liquid as well as the spectrometer is presented along with results of their performance.

  3. Recirculating 1-K-Pot for Pulse-Tube Cryostats

    Science.gov (United States)

    Paine, Christopher T.; Naylor, Bret J.; Prouve, Thomas

    2013-01-01

    A paper describes a 1-K-pot that works with a commercial pulse tube cooler for astrophysics instrumentation testbeds that require temperatures closed-cycle 1K-pot system for the pulse tube cooler requires a heat exchanger on the pulse tube, a flow restriction, pump-out line, and pump system that recirculates helium-4. The heat exchanger precools and liquefies helium- 4 gas at the 2.5 to 3.5 K pulse tube cold head. This closed-cycle 1-K-pot system was designed to work with commercially available laboratory pulse tube coolers. It was built using common laboratory equipment such as stainless steel tubing and a mechanical pump. The system is self-contained and requires only common wall power to operate. The lift of 15 mW at 1.1 K and base temperature of 0.97 K are provided continuously. The system can be scaled to higher heat lifts of .30 to 50 mW if desired. Ground-based telescopes could use this innovation to improve the efficiency of existing cryo

  4. Engineering development for a small-scale recirculator experiment

    International Nuclear Information System (INIS)

    Newton, M.A.; Deadrick, F.J.; Hanks, R.L.; Hawkins, S.A.; Holm, K.A.; Kirbie, H.C.; Karpenko, V.P.; Nattrass, L.A.; Longinotti, D.B.

    1995-01-01

    Lawrence Livermore National Laboratory (LLNL) is evaluating the physics and technology of recirculating induction accelerators for heavy-ion inertial-fusion drivers. As part of this evaluation, the authors are building a small-scale recirculator to demonstrate the concept and to use as a test bed for the development of recirculator technologies. System designs have been completed and components are presently being designed and developed for the small-scale recirculator. This paper discusses results of the design and development activities that are presently being conducted to implement the small-scale recirculator experiments. An, overview of the system design is presented along with a discussion of the implications of this design on the mechanical and electrical hardware. The paper focuses primarily on discussions of the development and design of the half-lattice period hardware and the advanced solid-state modulator

  5. NGL recovery being hiked by natural-gasoline recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rivas M, M.; Bracho, J.L. [Lagoven S.A., Maracaibo (Venezuela); Murray, J.E. [Murray (James E.), Corpus Christi, TX (United States)

    1997-07-07

    Construction will be completed later this year at two compression plants operated by Lagoven, S.A., to install natural-gasoline recirculation to improve NGL recovery. The project is the result of a study of condensate-stream recirculation and absorber operations at the compression plants Tia Juana 2 (PCTJ-2) and Tia Juana 3 (PCTJ-3), offshore Lake Maracaibo in western Venezuela. The PCTJ-2 and PCTJ-3 gas compression plants have two systems: gas compression and NGL extraction. Previous analysis of the NGL extraction and fractionation processes of Lagoven determined that there are two practical and attractive alternatives for the recirculation of the condensate streams in PCTJ-2 and 3: recirculation of natural gasoline from the Ule LPG plant; recirculation of a conditioned condensate from the de-ethanizer tower of each plant. Both alternatives are discussed. Also described are fractionation capacity, and modifications for adding absorption and fractionation.

  6. The study of recirculating aquaculture system in pond and its purification effect

    Science.gov (United States)

    Qu, Jiangqi; Zhang, Qingjing; Jia, Chengxia; Liu, Pan; Yang, Mu

    2017-05-01

    In this paper, a recirculating aquaculture purification system (RAPS) was designed to solve the problems of aquaculture pollution and shortage of freshwater resource according to the characteristic of northern freshwater ponds of China. The system were arranged in series and composed of high density culture pond, deposit pond, floating and submerged plant pond, ecological floating bed pond and biofilm filtrate pond. At the fish density of 20~30kg/m3 in the high density culture pond, the water quality parameters were monitored seasonally. The results indicated that the removal rate of total nitrogen, total phosphorus, ammonia nitrogen and nitrite nitrogen in the recirculating aquaculture system were 69.59%, 77.89%, 72.54% and 68.68%, respectively. The floating and submerged plant pond and ecological floating bed pond can remove TN and TP obviously, and increase dissolved oxygen and transparency significantly. And the biofilm filtrate pond has good effect of removing ammonium nitrogen and nitrite nitrogen, meanwhile, the microbial communities in the recirculating aquaculture system regulate on the water quality. Therefore, the RAPS show significant effects on water saving and pollution emission reducing.

  7. Beam Dynamics Studies in Recirculating Machines

    CERN Document Server

    Pellegrini, Dario; Latina, A

    The LHeC and the CLIC Drive Beam share not only the high-current beams that make them prone to show instabilities, but also unconventional lattice topologies and operational schemes in which the time sequence of the bunches varies along the machine. In order to asses the feasibility of these projects, realistic simulations taking into account the most worrisome effects and their interplays, are crucial. These include linear and non-linear optics with time dependent elements, incoherent and coherent synchrotron radiation, short and long-range wakefields, beam-beam effect and ion cloud. In order to investigate multi-bunch effects in recirculating machines, a new version of the tracking code PLACET has been developed from scratch. PLACET2, already integrates most of the effects mentioned before and can easily receive additional physics. Its innovative design allows to describe complex lattices and track one or more bunches accordingly to the machine operation, reproducing the bunch train splitting and recombinat...

  8. Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data

    Directory of Open Access Journals (Sweden)

    M. Marnela

    2013-05-01

    Full Text Available The volume, heat and freshwater transports in the Fram Strait are estimated from geostrophic computations based on summer hydrographic data from 1984, 1997, 2002 and 2004. In these years, in addition to the usually sampled section along 79° N, a section between Greenland and Svalbard was sampled further north. Quasi-closed boxes bounded by the two sections and Greenland and Svalbard can then be formed. Applying conservation constraints on these boxes provides barotropic reference velocities. The net volume flux is southward and varies between 2 and 4 Sv. The recirculation of Atlantic water is about 2 Sv. Heat is lost to the atmosphere and the heat loss from the area between the sections averaged over the four years is about 10 TW. The net heat (temperature transport is 20 TW northward into the Arctic Ocean, with large interannual differences. The mean net freshwater added between the sections is 40 mSv and the mean freshwater transport southward across 79° N is less than 60 mSv, indicating that most of the liquid freshwater leaving the Arctic Ocean through Fram Strait in summer is derived from sea ice melt in the northern vicinity of the strait. In 1997, 2001 and 2003 meridional sections along 0° longitude were sampled and in 2003 two smaller boxes can be formed, and the recirculation of Atlantic water in the strait is estimated by geostrophic computations and continuity constraints. The recirculation is weaker close to 80° N than close to 78° N, indicating that the recirculation is mainly confined to the south of 80° N. This is supported by the observations in 1997 and 2001, when only the northern part of the meridional section, from 79° N to 80° N, can be computed with the constraints applied. The recirculation is found strongest close to 79° N.

  9. The moderating role of cultural affiliation in the link between emotional closeness to grandparents and adolescent adjustment difficulties and prosocial behavior.

    Science.gov (United States)

    Attar-Schwartz, Shalhevet; Khoury-Kassabri, Mona

    2016-01-01

    A growing body of research has shown the positive contribution of grandparents to adolescents' well-being. However, studies often overlook the cultural context in which this relationship is embedded. The current study examined whether emotional closeness to the grandparent identified by the adolescents as their closest grandparent varied among Arab and Jewish adolescents and whether cultural affiliation serves as a moderator in the association between emotional closeness to grandparents and adolescent adjustment difficulties and prosocial behaviors. The study was based on a sample of 2,751 Jewish and Arab secondary school students (aged 12-18) from Israel who completed a structured questionnaire. Among the whole sample, greater emotional closeness to the closest grandparent was associated with reduced emotional symptoms, reduced hyperactivity, and increased prosocial behaviors. While there were lower levels of emotional closeness to the closest grandparents among Arab adolescents, emotional closeness to grandparents was found to be more strongly associated with reduced emotional symptoms and increased prosocial behavior among Arab adolescents than among Jewish adolescents. These findings emphasize the importance of considering culture when examining intergenerational relationships in the family and their contribution to grandchildren's well-being. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  10. Identification of biofloc microscopic composition as the natural bioremediation in zero water exchange of Pacific white shrimp, Penaeus vannamei, culture in closed hatchery system

    Science.gov (United States)

    Manan, Hidayah; Moh, Julia Hwei Zhong; Kasan, Nor Azman; Suratman, Suhaimi; Ikhwanuddin, Mhd

    2017-09-01

    Study on the microscopic composition of biofloc in closed hatchery culture system was carried out to determine the interaction between the aggregation flocs in the bioremediation process for the decomposition and degradation of organic matter loaded in the shrimp culture tanks. The study was done for 105 days of culture period in zero water exchange. All of the organic loaded in the culture tanks identified comes from the shrimp feces, uneaten fed, and the decomposed macro- and microorganisms died in the culture tanks. All of the microscopic organisms in the biofloc were identified using Advance microscopes Nikon 80i. From the present study, there were abundances and high varieties of phytoplankton, zooplankton, protozoa, nematodes and algae species identified as aggregates together in the flocs accumulation. All of these microscopic organisms identified implemented the symbiotic process together for food supply, become the algae grazer, act as natural water stabilizer in regulating the nutrients in culture tank and serve as decomposer for dead organic matter in the water environment. Heterotrophic bacteria identified from Pseudomonas and Aeromonas family consumed the organic matter loaded at the bottom of culture tank and converted items through chemical process as useful protein food to be consumed back by the shrimp. Overall it can be concluded that the biofloc organisms identified really contributed as natural bioremediation agents in zero water exchange culture system to ensure the water quality in the optimal condition until the end of culture period.

  11. Hydraulic study of parallel channels coupled to recirculation loops

    International Nuclear Information System (INIS)

    Campos G, R. M.; Cecenas F, M.

    2009-10-01

    In this work is integrated a model of recirculation loops that allows to characterize each loop for separate and with which is possible to analyze events as shot of recirculation bombs or its transfer of high to low speed. The recirculation pattern is integrated to a model of 36 channels in parallel that represents the core of a BWR. Because the core reactor is conformed by fuel assemblies physically prepared in a parallel arrangement, it is natural to obtain a parallel application of complete pattern, where are have 36 channels tasks more other two tasks that calculates recirculation and punctual kinetics, respectively. As initial test of system, which even it is found in development, was analyzed a discharge of both recirculation pumps. In this test transitory it is only verified the hydraulic behavior, the power is imposed artificially as frontier condition that is function of flow in the calculated core by the recirculation pattern. The pattern of thermal hydraulics channel and the recirculation loops are programmed in language C, the neutronic pattern is programmed in Fortran 77. For the simulations was used a work station Alpha Station DS20E with operative system Unix and the communication system Parallel Virtual Machine, that allows to a heterogeneous collection of computers in net to work like a virtual computer in parallel. (Author)

  12. Recirculating induction accelerators for inertial fusion: Prospects and status

    International Nuclear Information System (INIS)

    Friedman, A.; Barnard, J.J.; Cable, M.D.

    1995-01-01

    The US is developing the physics and technology of induction accelerators for heavy-ion beam-driven inertial fusion. The recirculating induction accelerator repeatedly passes beams through the same set of accelerating and focusing elements, thereby reducing both the length and gradient of the accelerator structure. This promises an attractive driver cost, if the technical challenges associated with recirculation can be met. Point designs for recirculator drivers were developed in a multi-year study by LLNL, LBNL, and FM Technologies, and that work is briefly reviewed here. To validate major elements of the recirculator concept, we are developing a small (4-5-m diameter) prototype recirculator which will accelerate a space-charge-dominated beam of K + ions through 15 laps, from 80 to 320 keV and from 2 to 8 mA. Transverse beam confinement is effected via permanent-magnet quadrupoles; bending is via electric dipoles. This ''Small Recirculator'' is being developed in a build-and-test sequence of experiments. An injector, matching section, and linear magnetic channel using seven half-lattice periods of permanent-magnet quadrupole lenses are operational. A prototype recirculator half-lattice period is being fabricated. This paper outlines the research program, and presents initial experimental results

  13. Aerobic degradation of methyl tert-butyl ether in a closed symbiotic system containing a mixed culture of Chlorella ellipsoidea and Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Zhong, Weihong; Li, Yixiao; Sun, Kedan; Jin, Jing; Li, Xuanzhen; Zhang, Fuming; Chen, Jianmeng

    2011-01-30

    The contamination of groundwater by methyl tert-butyl ether (MTBE) is one of the most serious environmental problems around the world. MTBE degradation in a closed algal-bacterial symbiotic system, containing a mixed culture of Methylibium petroleiphilum PM1 and Chlorella ellipsoidea, was investigated. The algal-bacterial symbiotic system showed increased MTBE degradation. The MTBE-degradation rate in the mixed culture (8.808 ± 0.007 mg l(-1) d(-1)) was higher than that in the pure bacterial culture (5.664 ± 0.017 mg l(-1) d(-1)). The level of dissolved oxygen was also higher in the mixed culture than that in the pure bacterial culture. However, the improved efficiency of MTBE degradation was not in proportional to the biomass of the alga. The optimal ratio of initial cell population of bacteria to algae was 100:1. An immobilized culture of mixed bacteria and algae also showed higher MTBE degradation rate than the immobilized pure bacterial culture. A mixed culture with algae and PM1 immobilized separately in different gel beads showed higher degradation rate (8.496 ± 0.636 mg l(-1) d(-1)) than that obtained with algae and PM1 immobilized in the same gel beads (5.424 ± 0.010 mg l(-1) d(-1)). Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Freshwater Institute: Focused on improving recirculating aquaculture system technology

    Science.gov (United States)

    Recirculating aquaculture system (RAS) technologies help to overcome barriers to domestic aquaculture expansion and enhance the sustainability of the modern fish farming industry through reduction in environmental impacts. With RAS, fish farm expansion is no longer highly constrained by competition ...

  15. Contribution to the study of recirculating flows

    International Nuclear Information System (INIS)

    Grand, Dominique

    1975-01-01

    The technology of the integrated primary circuit of French LMFBR type reactors involves many difficulties relating to heat transfer and hydraulics of the sodium masses inside the reactor. The work reported was a basic research supporting said reactor type development. Recirculating flows were studied inside a rectangular cavity, in the presence of body forces. Results given were obtained from numerical simulation, experimental investigation and a formal theoretical analysis. Solutions were obtained using the numerical integration of the conservation equation for a planar isothermal laminar flow driven by a mobile wall. The turbulent flow was experimentally investigated, the fluid being then driven through a mixing layer in common with a channel flow. Local velocity measurements in isothermal flow were effected using a laser-anemometer. In the occurrence of heat transfer, the temperature field only was scanned; complementary data were also obtained from color Schlieren vizualisation. A theoretical study of the flow was done at high Reynolds number. The flow inside the cavity was then separated in two parts: an external part (the non-viscous core) located at the center of the cavity and an internal part, the shear region, about the walls. An inclusive solution connecting both parts was developed in the framework of the laminar flow; results obtained are in good agreement with the numerical data. (author) [fr

  16. ENVIRONMENTAL CHARACTERISTICS OF DIESEL ENGINE WITH UTILIZING EXHAUST GASES RECIRCULATION

    OpenAIRE

    Petar Kazakov

    2016-01-01

    From the various methods for reducing harmful exhaust emissions as combustion control, improved fuel injection form of the combustion chamber, recirculation of the combustion products, impact of smoke particles, the addition of water, synthetic fuel. Is established that the system for recirculation of exhaust gas is one of the most effective methods for obtaining of lower values of NOx, because the reduced temperature of the combustion process and excess oxygen.

  17. Numerical investigation on the recirculation in annular jet pumps

    International Nuclear Information System (INIS)

    Xiao, Longzhou; Long, Xinping; Zeng, Qinglong; Yang, Xuelong; Li, Xiaohong

    2013-01-01

    The flow within the annular jet pump (AJP), in some degree, resembles the annular wall jet developing in a pipe with great axial pressure gradient. In some working conditions, there exists the backflow near the centerline. However this differs from the case in a center jet pump (CJP) that the recirculation emerges near the inner wall of the throat. The recirculation in AJP affects a lot to its performance, especially when AJP is utilized to convey something alive, such as fish. This paper aims to numerically study the impact of two parameters, the flow ratio M and the area ratio A, on the location, size and formation of the recirculation in AJP. After being validated by the experimental results, the RNG k-ε turbulent model was adopted. It is found that: (1) As M increases, the width and height of the recirculation in AJP decreases, and the separation point of the recirculation shifts gradually far away from the nozzle exit while the reattachment point slightly moves; (2) As A becomes larger, the width and height of the recirculation enlarged, with M keeping constant; (3) For AJP with constant A, the recirculation emerges when M declines to a critical value, and the value varies linearly with A; (4) The Craya-Curtet number C t and the momentum ratio J, which take A and M into whole consideration, are also feasible in describing the disappearance of the recirculation. However the critical value of C t and J are different from that discovered in CJP. The critical C t increases with decreasing A and the critical momentum ratio J c experiences a linear relationship with A.

  18. Modeling of TAN in recirculating aquaculture systems by AQUASIM

    DEFF Research Database (Denmark)

    Arvin, Erik; Pedersen, Lars-Flemming

    2011-01-01

    Modeling of total ammonium nitrogen (TAN) in recirculating aquaculture systems (RAS) contribute to identifying and quantifying the most important processes and their relative contribution to removal of TAN. AQUASIM is a flexible modular simulation system for water quality in natural and technical...... systems developed by EAWAG (Reichert, 1994). AQUASIM allows simulating complex biological, chemical and physical processes in standardized hydraulic systems. We used AQUASIM to model the steady state TAN concentrations in 12 experimental recirculating aquaculture systems (RAS) operated by DTU AQUA...

  19. The Impact of Tropical Recirculation on Polar Composition

    Science.gov (United States)

    Strahan, S. E.; Schoeberl, M. R.; Steenrod, S. D.

    2009-01-01

    We derive the tropical modal age of air from an analysis of the water vapor tape recorder. We combine the observationally derived modal age with mean age of air from CO2 and SF6 to create diagnostics for the independent evaluation of the vertical transport rate and horizontal recirculation into the tropics between 16-32 km. These diagnostics are applied to two Global Modeling Initiative (GMI) chemistry and transport model (CTM) age tracer simulations to give new insights into the tropical transport characteristics of the meteorological fields from the GEOS4-GCM and the GEOS4-DAS. Both simulations are found to have modal ages that are in reasonable agreement with the empirically derived age (i.e ., transit times) over the entire altitude range. Both simulations show too little horizontal recirculation into the tropics above 22 km, with the GEOS4-DAS fields having greater recirculation. Using CH4 as a proxy for mean age, comparisons between HALOE and model CH4 in the Antarctic demonstrate how the strength of tropical recirculation affects polar composition in both CTM experiments. Better tropical recirculation tends to improve the CH4 simulation in the Antarctic. However, mean age in the Antarctic lower stratosphere can be compromised by poor representation of tropical ascent, tropical recirculation, or vortex barrier strength. The connection between polar and tropical composition shown in this study demonstrates the importance of diagnosing each of these processes separately in order to verify the adequate representation of the processes contributing to polar composition in models.

  20. Mathematical modelling of nutrient balance of a goldfish (Carassius auratus Linn. recirculating aquaculture system (GRAS

    Directory of Open Access Journals (Sweden)

    Sudeep Puthravilakom Sadasivan Nair

    2010-08-01

    Full Text Available In the present study, a goldfish (Carassius auratus Linn. recirculating aquaculture system (GRAS has been developed. The GRAS consisted of a culture tank, a screen filter and a foam fractionator for removal of particulate and dissolved solids and a trickling filter for conversion of ammonium- and nitrite-nitrogen to relatively harmless nitrate-nitrogen. The culture of goldfish at a stocking density of 1.08 kg/m3 was continued for a period of two and half months. Based on mass balance analysis of ammonium- and nitrate-nitrogen and assuming the trickling filter to be a plug flow reactor, a model was formulated to determine the necessary recirculation flow rate at different times of culture for maintaining the major nutrients, viz., ammonium- and nitrate-nitrogen below their permissible limits. The model was calibrated and validated using the real time data obtained from the experimental run. The high values of coefficient of determination and low values of root mean square error show the effectiveness of the model.

  1. Technical note: In vitro total gas and methane production measurements from closed or vented rumen batch culture systems.

    Science.gov (United States)

    Cattani, M; Tagliapietra, F; Maccarana, L; Hansen, H H; Bailoni, L; Schiavon, S

    2014-03-01

    This study compared measured gas production (GP) and computed CH4 production values provided by closed or vented bottles connected to gas collection bags. Two forages and 3 concentrates were incubated. Two incubations were conducted, where the 5 feeds were tested in 3 replicates in closed or vented bottles, plus 4 blanks, for a total of 64 bottles. Half of the bottles were not vented, and the others were vented at a fixed pressure (6.8 kPa) and gas was collected into one gas collection bag connected to each bottle. Each bottle (317 mL) was filled with 0.4000 ± 0.0010 g of feed sample and 60 mL of buffered rumen fluid (headspace volume = 257 mL) and incubated at 39.0°C for 24 h. At 24 h, gas samples were collected from the headspace of closed bottles or from headspace and bags of vented bottles and analyzed for CH4 concentration. Volumes of GP at 24 h were corrected for the gas dissolved in the fermentation fluid, according to Henry's law of gas solubility. Methane concentration (mL/100mL of GP) was measured and CH4 production (mL/g of incubated DM) was computed using corrected or uncorrected GP values. Data were analyzed for the effect of venting technique (T), feed (F), interaction between venting technique and feed (T × F), and incubation run as a random factor. Closed bottles provided lower uncorrected GP (-18%) compared with vented bottles, especially for concentrates. Correction for dissolved gas reduced but did not remove differences between techniques, and closed bottles (+25 mL of gas/g of incubated DM) had a greater magnitude of variation than did vented bottles (+1 mL of gas/g of incubated DM). Feeds differed in uncorrected and corrected GP, but the ranking was the same for the 2 techniques. The T × F interaction influenced uncorrected GP values, but this effect disappeared after correction. Closed bottles provided uncorrected CH4 concentrations 23% greater than that of vented bottles. Correction reduced but did not remove this difference. Methane

  2. Sulphur recirculation for reduced boiler corrosion; Minskad pannkorrosion med svavelrecirkulation

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Sven; Karlsson, Martin (Goetaverken Miljoe AB, Goeteborg (Sweden)); Blomqvist, Evalena; Baefver, Linda; Claesson, Frida; Davidsson, Kent (SP Sveriges Tekniska Forskningsinstitut, Boraas (Sweden)); Froitzheim, Jan; Pettersson, Jesper; Steenari, Britt-Marie (Chalmers Tekniska Hoegskola, Oorganisk miljoekemi, Goeteborg (Sweden))

    2010-03-15

    Sulphur recirculation is a new technology for reducing boiler corrosion and dioxin formation, which was demonstrated in full-scale tests performed at the Renova Waste to Energy plant at Saevenaes in Goeteborg (Sweden). Sulphur is recirculated from the flue gas cleaning back to the boiler, which reduces the chloride content of the deposits, which in turn reduces boiler corrosion and dioxin formation. Sulphur dioxide was separated from the flue gas in a wet scrubber by adding hydrogen peroxide, producing sulphuric acid. The sulphuric acid was injected into the furnace using nozzles with atomization air, surrounded by recirculated flue gas for improved mixing. By recirculating the sulphur, the sulphur dioxide concentration was increased in the boiler. Each sulphur atom passed the boiler several times and no external sulphur had to be added. Dioxin, ash, deposits and particle samplings together with 1000 h corrosion probe measurements were performed for normal operation (reference) and with sulphur recirculation respectively. During spring 2009, reference measurements were made and the recirculation system was installed and tested. During autumn 2009, a long term test with sulphur recirculation was made. An SO{sub 2} concentration of approximately 800 mg/m3 (n, d.g.) was maintained in the boiler by the system except during a period of extremely low sulphur content in the waste. The sulphur dioxide stack concentrations have been far below the emission limit. Sulphuric acid dew point measurements have shown that the sulphuric acid dosage did not lead to elevated SO{sub 3} concentrations, which may otherwise lead to low temperature corrosion. The chlorine content of both fly ash and boiler ash decreased and the sulphur content increased during the sulphur recirculation tests. The molar chlorine/sulphur ratio (Cl/S) decreased by two thirds in the fly ash as well as in the boiler ash, except for one sample. With sulphur recirculation in operation, the deposit growth was

  3. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture

    Directory of Open Access Journals (Sweden)

    S. Sumoharjo

    2013-06-01

    Full Text Available Integrated multi-trophic aquaculture pays more attention as a bio-integrated food production system that serves as a model of sustainable aquaculture, minimizes waste discharge, increases diversity and yields multiple products. The objectives of this research were to analyze the efficiency of total ammonia nitrogen biofiltration and its effect on carrying capacity of fish rearing units. Pilot-scale bioreactor was designed with eight run-raceways (two meters of each that assembled in series. Race 1-3 were used to stock silky worm (Tubifex sp as detrivorous converter, then race 4-8 were used to plant three species of leaf-vegetable as photoautotrophic converters, i.e; spinach (Ipomoea reptana, green mustard (Brassica juncea and basil (Ocimum basilicum. The three plants were placed in randomized block design based on water flow direction. Mass balance of nutrient analysis, was applied to figure out the efficiency of bio-filtration and its effect on carrying capacity of rearing units. The result of the experiment showed that 86.5 % of total ammonia nitrogen removal was achieved in 32 days of culturing period. This efficiency able to support the carrying capacity of the fish tank up to 25.95 kg/lpm with maximum density was 62.69 kg/m3 of fish biomass productionDoi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85 [How to cite this article: Sumoharjo, S.  and Maidie, A. (2013. Evaluation on Biofilter in Recirculating Integrated Multi-Trophic Aquaculture.  International Journal of  Science and Engineering, 4(2,80-85. Doi: http://dx.doi.org/10.12777/ijse.4.2.2013.80-85

  4. Up close and real: living and learning in a remote community builds students' cultural capabilities and understanding of health disparities.

    Science.gov (United States)

    Thackrah, Rosalie D; Hall, Maeva; Fitzgerald, Kathryn; Thompson, Sandra C

    2017-07-06

    Rural and remote communities in Australia fare worse than their urban counterparts across major health indicators, with geographic isolation, restricted accessibility to health services, socioeconomic disadvantage, lifestyle and behavioural factors all implicated in poorer health outcomes. Health disparities, which are especially stark in Australian Aboriginal and Torres Strait Islander populations, underscore the urgent need to build a culturally responsive and respectful rural health workforce. Allied health student placements in settings with high Aboriginal populations provide opportunities for the development of cultural capabilities and observation of the causes and impact of health disparities. A service learning pedagogy underpinned by strong campus-community partnerships can contribute to effective situated learning. Positive placement experiences can also encourage future rural practice alleviating workforce shortages. This article reports on the first stage of a proposed longitudinal investigation into the impact of remote placements on clinical practice and employment choices. In-depth interviews were undertaken with health science students and recent graduates from Australian universities who spent up to 4 weeks at the remote community of Mt. Magnet (Badimaya country) in Western Australia. Interviews, which occurred between two and 12 months following the placement were recorded, transcribed and thematically analysed for patterns of meaning. Factors which contributed to positive professional, personal and socially responsive learning experiences were identified. These included pre-placement cultural training to build understanding of the local Aboriginal community, peer support, community engagement, cultural exchanges and interprofessional collaboration. Highlights were associated with relationship-building in the community and opportunities to apply insights into Aboriginal cultural ways to clinical and community practice. The role of the

  5. Design considerations for long-pulse, high-repetition-rate modulators for recirculating heavy-ion accelerators

    International Nuclear Information System (INIS)

    Newton, M.A.; Reginato, L.L.; Yu, S.S.

    1991-06-01

    Heavy-ion accelerators are considered to be one of the promising driver alternatives for inertial fusion. In an inertial fusion driver, multiple beams of heavy-ions are accelerated to kinetic energies consistent with the fusion target requirements. During acceleration, the beams of heavy ions are compressed in time from an initial pulse duration that range from 10's to 100's of microseconds to a final pulse duration of approximately 10 nanoseconds. The compressed beam of heavy ions is then focused on the target in a reactor chamber where the energy released from the fusion reaction is converted to thermal energy and eventually to electricity. A recirculator is an induction accelerator which accelerates the particles and bends them in a closed path with pulsed dipole magnets. A single beam traverses the same accelerating cavities many times (50--100) to acquire its final energy. The primary motivation to evaluate recirculators is the potential for low cost that results from re-using many of the most expensive accelerator components, such as the induction cells, pulsers, and focusing magnets, during an acceleration sequence. One of the areas of technology that is critical to the feasibility of a recirculator is the modulator system required to accelerate the ion beams. This system greatly impacts the overall design of the recirculating accelerator. System studies have been conducted to evaluate the cost and efficiency of several recirculator configurations as function of various parameters. These system studies have helped identify desirable induction cell driver characteristics. These characteristics and the trade-offs that were evaluated will be presented and discussed

  6. Hydrothermal carbonization: process water characterization and effects of water recirculation.

    Science.gov (United States)

    Stemann, Jan; Putschew, Anke; Ziegler, Felix

    2013-09-01

    Poplar wood chips were treated hydrothermally and the increase of process efficiency by water recirculation was examined. About 15% of the carbon in the biomass was dissolved in the liquid phase when biomass was treated in de-ionized water at 220 °C for 4 h. The dissolved organic matter contained oxygen and was partly aerobically biodegradable. About 30-50% of the total organic carbon originated from organic acids. A polar and aromatic fraction was extracted and a major portion of the organic load was of higher molecular weight. By process water recirculation organic acids in the liquid phase concentrated and catalyzed dehydration reactions. As a consequence, functional groups in hydrothermally synthesized coal declined and dewaterability was enhanced. Recirculated reactive substances polymerized and formed additional solid substance. As a result, carbon and energetic yields of the produced coal rose to 84% and 82%, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Comparing the effects of high vs. low nitrate on the health, performance, and welfare of juvenile rainbow trout Oncorhynchus mykiss within water recirculating aquaculture systems

    Science.gov (United States)

    Previous research indicates that rainbow trout (Oncorhynchus mykiss) begin to exhibit health and welfare problems when cultured within water recirculating aquaculture systems (WRAS) operated at low exchange (6.7 days hydraulic retention time) and a mean feed loading rate of 4.1 kg feed/m3 daily make...

  8. Evaluation of ozonation on levels of the off-flavor compounds geosmin and 2-methylisoborneol in water and rainbow trout Oncorhynchus mykiss from water recirculation aquaculture systems

    Science.gov (United States)

    Common “off-flavors” in fish cultured in water recirculation aquaculture systems (WRAS) are “earthy” and “musty” due to the presence of the off-flavor metabolites geosmin and 2-methylisoborneol (MIB), respectively. Previously, ozone addition has been applied to WRAS at relatively low doses to break...

  9. The impact of tropical recirculation on polar composition

    Directory of Open Access Journals (Sweden)

    S. E. Strahan

    2009-04-01

    Full Text Available We derive the tropical modal age of air from an analysis of the water vapor tape recorder. We combine the observationally derived modal age with mean age of air from CO2 and SF6 to create diagnostics for the independent evaluation of the vertical transport rate and horizontal recirculation into the tropics between 16–32 km. These diagnostics are applied to two Global Modeling Initiative (GMI chemistry and transport model (CTM age tracer simulations to give new insights into the tropical transport characteristics of the meteorological fields from the GEOS4-GCM and the GEOS4-DAS. Both simulations are found to have modal ages that are in reasonable agreement with the empirically derived age (i.e., transit times over the entire altitude range. Both simulations show too little horizontal recirculation into the tropics above 22 km, with the GEOS4-DAS fields having greater recirculation. Using CH4 as a proxy for mean age, comparisons between HALOE and model CH4 in the Antarctic demonstrate how the strength of tropical recirculation affects polar composition in both CTM experiments. Better tropical recirculation tends to improve the CH4 simulation in the Antarctic. However, mean age in the Antarctic lower stratosphere can be compromised by poor representation of tropical ascent, tropical recirculation, or vortex barrier strength. The connection between polar and tropical composition shown in this study demonstrates the importance of diagnosing each of these processes separately in order to verify the adequate representation of the processes contributing to polar composition in models.

  10. Exceptional prison conditions and the quality of prison life: Prison size and prison culture in Norwegian closed prisons

    OpenAIRE

    Johnsen, Berit; Granheim, Per Kristian; Helgesen, Janne

    2011-01-01

    This paper discusses the quality of prison life and prison size in relation to the notion of ‘Scandinavian exceptionalism’. Using the questionnaires ‘Measuring the Quality of Prison Life’ (MQPL) for prisoners and ‘Staff Measuring the Quality of Prison Life’ (SQL) for staff, data were collected from all 32 closed prisons in Norway. Based on the assumption that prison officers’ working lives, their perspectives and their values influence prisoners’ quality of life, the main focus in the paper i...

  11. Culture expansion of adipose derived stromal cells. A closed automated Quantum Cell Expansion System compared with manual flask-based culture

    DEFF Research Database (Denmark)

    Haack-Sørensen, Mandana; Follin, Bjarke; Juhl, Morten

    2016-01-01

    Background: Adipose derived stromal cells (ASCs) are a rich and convenient source of cells for clinical regenerative therapeutic approaches. However, applications of ASCs often require cell expansion to reach the needed dose. In this study, cultivation of ASCs from stromal vascular fraction (SVF......) over two passages in the automated and functionally closed Quantum Cell Expansion System (Quantum system) is compared with traditional manual cultivation. Methods: Stromal vascular fraction was isolated from abdominal fat, suspended in α-MEM supplemented with 10% Fetal Bovine Serum and seeded......, and endotoxins, in addition to the assessment of cell counts, viability, immunophenotype, and differentiation potential. Results: The viability of ASCs passage 0 (P0) and P1 was above 96%, regardless of cultivation in flasks or Quantum system. Expression of surface markers and differentiation potential...

  12. Recirculating aquaculture system for high density production of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Vu, Minh Thi Thuy; Øie, Gunvor; Reinertsen, Helge

    2013-01-01

    The calanoid copepod Acartia tonsa (Dana) is one of the most promising copepod species for marine larviculture. This species has a wide tolerance to temperature and salinity, small size, can produce resting eggs. All their nauplii, copepodites and adults can be use as excellent feeds for marine...... fish larvae. Yet, the biomass and egg production of A. tonsa has been limited mainly due to the challanges to culture them at high density. The development of recirculating aquaculture system (RAS) in recent decades has opened a new culturing system that is expected to provide more stable environmental...... conditions to favor the production of A. tonsa at high density. The current study was initiated to preliminarily apply a recircultating aquaculture system (RAS) for A. tonsa production. A flow through aquaculture system (FTAS) was also run in parallel to evaluate the capacity of RAS compared to the FTAS...

  13. Characterization of Mycobacterium salmoniphilum as causal agent of mycobacteriosis in Atlantic salmon, Salmo salar L., from a freshwater recirculation system.

    Science.gov (United States)

    Aro, L; Correa, K; Martínez, A; Ildefonso, R; Yáñez, J M

    2014-04-01

    Thirty Atlantic salmon, Salmo salar L., with low corporal condition relative to other fish present in the culture system, were sampled from a freshwater recirculation pisciculture located in Chile. The most characteristic signs and lesions were cachexia and presence of multiple greyish-white granulomas within internal organs. The external and internal lesions, along with the microscopic, histologic and biochemical findings, were consistent with mycobacteriosis. The identification of Mycobacterium salmoniphilum as the causal agent of the lesions was possible through the use of molecular analyses. This study represents the first report of Mycobacterium salmoniphilum in a freshwater recirculation system and the first case of fish mycobacteriosis described in Chile. © 2013 John Wiley & Sons Ltd.

  14. Self-selection bias and manufacturing firms' demand for water recirculation

    OpenAIRE

    Steven Renzetti; Joel Brueau; Michel Villeneuve

    2009-01-01

    Relatively little is known of the factors which might influence firms' water recirculation decisions. This paper estimates an econometric model that accounts for potential self-selection bias and considers two facets of firms' recirculation behaviour: first, the discrete decision of whether to recirculate and, second, the decision of how much to recirculate. The model is estimated by applying the Heckman two-stage estimation procedure to data from Environment Canada's Industrial Water Use Sur...

  15. Production value optimization with intermediate jig product recirculation

    Directory of Open Access Journals (Sweden)

    Pielot Joachim

    2016-01-01

    Full Text Available The paper describes the result of the production value increase in systems with two and three jigs and recirculation of the interemediate product compared to the output value obtained from a single jig. The increase is greater when the reference ash content in the concentrate is lower.

  16. Mechanical design of the recirculating, terminal pumping in the Lund ...

    Indian Academy of Sciences (India)

    A recirculating terminal pumping system has been installed in the 3 MV Pelletron tandem accelerator in Lund. An extremly limited space in the high voltage terminal and the absence of electrical power in the terminal, forced us to provide a unique design for the installation and powering of the new pumps. Details of the ...

  17. Experimental studies of impact of exhaust gas recirculation on the ...

    African Journals Online (AJOL)

    This paper considers the problem of reducing the nitrogen oxides emissions in exhaust gases (EG) of diesel engine by exhaust gas recirculation (EGR). Based on the carried out study the influence of EGR on technical-and-economic and environmental performance of a diesel engine was found as well as main directions of ...

  18. Numerical analysis and control of the recirculation bubble strength ...

    African Journals Online (AJOL)

    user

    Abstract. Numerical investigation of the turbulent jet flows, both central and annular type of jets has been carried out with the introduction of swirl at the inlet using the modified ε κ − model. It was observed that the recirculation bubble generated by the central jet without swirl diminishes in size due to increase in swirl number, ...

  19. Constrained control of a once-through boiler with recirculation

    DEFF Research Database (Denmark)

    Trangbæk, K

    2008-01-01

    There is an increasing need to operate power plants at low load for longer periods of time. When a once-through boiler operates at a sufficiently low load, recirculation is introduced, significantly altering the control structure. This paper illustrates the possibilities for using constrained...

  20. Recirculating steam generator operation at very low power

    International Nuclear Information System (INIS)

    Holcblat, A.

    2001-01-01

    The behaviour of recirculating SG's at very low power has been thoroughly investigated by laboratory and on-site tests as well as numerical simulations. A special experimental program dedicated to recirculation threshold determination has been performed on the Freon SG mock-up CLOTAIRE. These laboratory data are completed with transients of feedwater injections at hot stand-by on two instrumented SG's, one boiler type SG and one economizer type SG. The phenomena are different on both types. In boiler SG's, the SG behaves like a U-tube and recirculation stops around 2% load at stand-by temperature and water level. In economizer SG's, the presence of 2 separate down-comers and a divider plate inside the tube bundle allows a recirculation loop by-passing the separators. The mixing of saturated and cold water induced by this loop limits down-comer cooling and thus alleviates the thermal load on the tube sheet. These tests were used to validate the SG transient analysis 1-D code ANETH. (author)

  1. Microscreen effects on water quality in replicated recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2015-01-01

    This study investigated the effects of three microscreen mesh sizes (100, 60 and 20 μm) on water quality and rainbow trout (Oncorhynchus mykiss) performance compared to a control group without microscreens, in triplicated recirculating aquaculture systems (RAS). Operational conditions were kept...

  2. Influence of recirculation rate on the performance of a combined ...

    African Journals Online (AJOL)

    The objective of this study was to evaluate a combined anaerobic-aerobic upflow fixed-bed reactor with liquid phase recirculation for the removal of nitrogen and organic matter from poultry slaughterhouse wastewater. The reactor performance was evaluated with a hydraulic retention time (HRT) of 11 h and three different ...

  3. Mechanical design of the recirculating, terminal pumping in the Lund ...

    Indian Academy of Sciences (India)

    Abstract. A recirculating terminal pumping system has been installed in the 3 MV Pelletron tan- dem accelerator in Lund. An extremly limited space in the high voltage terminal and the absence of electrical power in the terminal, forced us to provide a unique design for the installation and power- ing of the new pumps. Details ...

  4. Numerical analysis and control of the recirculation bubble strength ...

    African Journals Online (AJOL)

    Numerical investigation of the turbulent jet flows, both central and annular type of jets has been carried out with the introduction of swirl at the inlet using the modified κ −ε model. It was observed that the recirculation bubble generated by the central jet without swirl diminishes in size due to increase in swirl number, while in ...

  5. A recirculating incubation system for hatching small batches of fish ...

    African Journals Online (AJOL)

    This paper describes the design, construction and evaluation of the capacity of a re-circulating incubation system for hatching small batches of fish eggs. ... Water flowed out of the incubation unit through a small section of glass and then plastic tubing inserted through a second hole in the rubber stopper to a PVC drain ...

  6. Influence of recirculation rate on the performance of a combined ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2016-09-14

    Sep 14, 2016 ... produced in the reactor during anaerobic digestion, such as nitrate reducers during the denitrification step, thus eliminating the need for providing an external source of organic carbon. Therefore, the objective of this study was to evaluate the influence of effluent recirculation on the performance.

  7. Modeling Tar Recirculation in Biomass Fluidized Bed Gasification

    NARCIS (Netherlands)

    Heineken, Wolfram; De la Cuesta de Cal, Daniel; Zobel, Nico

    2016-01-01

    A biomass gasification model is proposed and applied to investigate the benefits of tar recirculation within a gasification plant. In the model, tar is represented by the four species phenol, toluene, naphthalene, and benzene. The model is spatially one-dimensional, assuming plug flow for the

  8. Impact assessment of concentrate recirculation on the landfill gas production

    Directory of Open Access Journals (Sweden)

    Džolev Nikola M.

    2016-01-01

    Full Text Available This paper explores the impact of concentrate recirculation, as a product of leachate treated by reverse osmosis plant, on the production of landfill gas at the real-scale landfill for municipal solid waste. In an effort to come up with results experimental measurements were carried out at the landfill in Bijeljina. All measurements performed, were divided into 3 groups. The aims of two groups of measurement were to determine landfill gas and methane yield from concentrate and leachate in laboratory conditions (1st group and to find out concentrations of oxidizing matters (COD and BOD5 present in leachate and concentrate at different points of treatment as well as its variability over the time (2nd group which could be used to calculate the potential of landfill gas and methane generation from concentrate by recirculation, theoretically. 3rd group of measurements, carried out in parallel, have goal to determine the quality and quantity of the collected landfill gas at wells throughout the landfill. The results of analysis carried out in this experimental research show the clear evidence of concentrate recirculation impact on methane production by increasing the landfill gas flow, as well as its concentration within the landfill gas composition, at the nearby well. Although results indicated relatively high impact of concentrate recirculation on landfill gas production, comparing to its theoretical potential, the influence on the landfill at whole, is negligible, due to relatively low volumes in recirculation with respect to its size and objectively low potential given by organic matter present in concentrate.

  9. Closed cycle gas dynamic laser

    International Nuclear Information System (INIS)

    Pinsley, E.A.

    1975-01-01

    The device includes a closed cycle gasdynamic laser wherein the lasing fluid is recirculated in a closed loop. The closed loop includes a nozzle array, a lasing cavity and a diffuser. The exit of the diffuser is connected to the inlet to the nozzle array with a fuel heat exchanger located in the lasing flow and a pumping means located between the heat exchanger and the nozzle array. To provide for cooling of the pumping means and to improve diffuser performance, gas bled from the diffuser is cooled by two heat exchangers and pumped into cooling passages in the pumping means. The heat exchangers for cooling the flow to the pumping means are located in series and carry fuel from a supply to an injector in said combustor and the heat exchanger in the lasing flow cools the fluid and carries the fuel from a supply to an injector in said combustor. (U.S.)

  10. Engine with exhaust gas recirculation system and variable geometry turbocharger

    Science.gov (United States)

    Keating, Edward J.

    2015-11-03

    An engine assembly includes an intake assembly, an internal combustion engine defining a plurality of cylinders and configured to combust a fuel and produce exhaust gas, and an exhaust assembly in fluid communication with a first subset of the plurality of cylinders. Each of the plurality of cylinders are provided in fluid communication with the intake assembly. The exhaust assembly is provided in fluid communication with a first subset of the plurality of cylinders, and a dedicated exhaust gas recirculation system in fluid communication with both a second subset of the plurality of cylinders and with the intake assembly. The dedicated exhaust gas recirculation system is configured to route all of the exhaust gas from the second subset of the plurality of cylinders to the intake assembly. Finally, the engine assembly includes a turbocharger having a variable geometry turbine in fluid communication with the exhaust assembly.

  11. Pelletron-based MeV-range electron beam recirculation

    CERN Document Server

    Crawford, A C; Sharapa, A N; Shemyakin, A

    1999-01-01

    In this paper we describe the successful recirculation of a DC electron beam at energies 1-1.5 MeV and currents up to 0.7 A with typical relative losses of 5-20x10 sup - sup 6. Currents of 200 mA were maintained for periods of up to five hours without a single breakdown. We found that the aperture-limiting diaphragm in the gun anode significantly increased the stability of the recirculation. We also found that the stability depended strongly on vacuum pressure in the beamline. The performance of the collector with transverse magnetic fields was found to be adequate for beam currents up to 0.6 A, which is in agreement with our low-energy bench test results. (author)

  12. Control of synchrotron radiation effects during recirculation with bunch compression

    International Nuclear Information System (INIS)

    Studies of beam quality during recirculation have been extended to an arc providing bunch compression with positive momentum compaction. It controls both incoherent and coherent synchrotron radiation (ISR and CSR) using methods including optics balance and generates little microbunching gain. We detail the dynamical basis for the design, discuss the design process, give an example, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of microbunching effects.

  13. Aircraft Recirculation Filter for Air-Quality and Incident Assessment

    OpenAIRE

    Eckels, Steven J.; Jones, Byron; Mann, Garrett; Mohan, Krishnan R.; Weisel, Clifford P.

    2014-01-01

    The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were an...

  14. Tracking studies in eRHIC energy-recovery recirculator

    Energy Technology Data Exchange (ETDEWEB)

    Meot, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Brooks, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ptitsyn, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Trbojevic, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tsoupas, N. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-07-13

    Beam and polarization tracking studies in eRHIC energy recovery electron recirculator are presented, based on a very preliminary design of the FFAG lattice. These simulations provide examples of some of the beam and spin optics aspects of the linear FFAG lattice concept and its application in eRHIC, they provide code benchmarking for synchrotron radiation and spin diffusion in addition, and pave the way towards end-to-end 6-D(phasespace)+3D(spin) tracking simulations.

  15. Maintenance of reactor recirculation pumps [Paper No.: II-1

    International Nuclear Information System (INIS)

    Ansari, M.A.; Bhat, K.P.

    1981-01-01

    At Tarapur Atomic Power Station (TAPS), two reactor recirculation pumps are provided, one each for the two reactor units. The performance of pumps has been uniformly good; however, leakage through the cartridge type, two stage, mechanical seals which are installed on these pumps was encountered on few occasions. The paper describes the leakage problems, identification of certain design deficiencies and rectification carried out at TAPS for overcoming these problems. (author)

  16. Seismic proving test of BWR primary loop recirculation system

    International Nuclear Information System (INIS)

    Sato, H.; Shigeta, M.; Karasawa, Y.

    1987-01-01

    The seismic proving test of BWR Primary Loop Recirculation system is the second test to use the large-scale, high-performance vibration table of Tadotsu Engineering Laboratory. The purpose of this test is to prove the seismic reliability of the primary loop recirculation system (PLR), one of the most important safety components in the BWR nuclear plants, and also to confirm the adequacy of seismic analysis method used in the current seismic design. To achieve the purpose, the test was conducted under conditions and scale as near as possible to actual systems. The strength proving test was carried out with the test model mounted on the vibration table in consideration of basic design earthquake ground motions and other conditions to confirm the soundness of structure and the strength against earthquakes. Detailed analysis and analytic evaluation of the data obtained from the test was conducted to confirm the adequacy of the seismic analysis method and earthquake response analysis method used in the current seismic design. Then, on the basis of the results obtained, the seismic safety and reliability of BWR primary loop recirculation of the actual plants was fully evaluated

  17. Investigation of Microbunching Instabilities in Modern Recirculating Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Cheng [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2017-05-21

    Particle accelerators are machines to accelerate and store charged particles, such as electrons or protons, to the energy levels for various scientific applications. A collection of charged particles usually forms a particle beam. There are three basic types of particle accelerators: linear accelerators (linac), storage-ring (or circular) accelerators, and recirculating accelerators. In a linac, particles are accelerated and pass through once along a linear or straight beamline. Storage-ring accelerators propel particles around a circular track and repetitively append the energy to the stored beam. The third type, also the most recent one in chronology, the recirculating accelerator, is designed to accelerate the particle beam in a short section of linac, circulate the beam, and then either continue to accelerate for energy boost or decelerate it for energy recovery. The beam properties of a linac machine are set at best by the initial particle sources. For storage rings, the beam equilibria are instead determined by the overall machine design. The modern recirculating machines share with linacs the advantages to both accelerate and preserve the beam with high beam quality, as well as efficiently reuse the accelerating components. The beamline design in such a machine configuration can however be much more complicated than that of linacs. As modern accelerators push toward the high-brightness or high-intensity frontier by demanding particles in a highly charged bunch (about nano-Coulomb per bunch) to concentrate in an ever-decreasing beam phase space (transverse normalized emittance about 1 μm and relative energy spread of the order of 10^-5 in GeV beam energy), the interaction amongst particles via their self-generated electromagnetic fields can potentially lead to coherent instabilities of the beam and thus pose significant challenges to the machine design and operation. In the past decade and a half, microbunching instability (MBI) has been one of the most

  18. The STREON Recirculation Chamber: An Advanced Tool to Quantify Stream Ecosystem Metabolism in the Benthic Zone

    Science.gov (United States)

    Brock, J. T.; Utz, R.; McLaughlin, B.

    2013-12-01

    The STReam Experimental Observatory Network is a large-scale experimental effort that will investigate the effects of eutrophication and loss of large consumers in stream ecosystems. STREON represents the first experimental effort undertaken and supported by the National Ecological Observatory Network (NEON).Two treatments will be applied at 10 NEON sites and maintained for 10 years in the STREON program: the addition of nitrate and phosphate to enrich concentrations by five times ambient levels and electrical fields that exclude top consumers (i.e., fish or invertebrates) of the food web from the surface of buried sediment baskets. Following a 3-5 week period, the sediment baskets will be extracted and incubated in closed, recirculating metabolic chambers to measure rates of respiration, photosynthesis, and nutrient uptake. All STREON-generated data will be open access and available on the NEON web portal. The recirculation chamber represents a critical infrastructural component of STREON. Although researchers have applied such chambers for metabolic and nutrient uptake measurements in the past, the scope of STREON demands a novel design that addresses multiple processes often neglected by earlier models. The STREON recirculation chamber must be capable of: 1) incorporating hyporheic exchange into the flow field to ensure measurements of respiration include the activity of subsurface biota, 2) operating consistently with heterogeneous sediments from sand to cobble, 3) minimizing heat exchange from the motor and external environment, 4) delivering a reproducible uniform flow field over the surface of the sediment basket, and 5) efficient assembly/disassembly with minimal use of tools. The chamber also required a means of accommodating an optical dissolved oxygen probe and a means to inject/extract water. A prototype STREON chamber has been designed and thoroughly tested. The flow field within the chamber has been mapped using particle imaging velocimetry (PIV

  19. Nitrogen oxides emissions from the MILD combustion with the conditions of recirculation gas.

    Science.gov (United States)

    Park, Min; Shim, Sung Hoon; Jeong, Sang Hyun; Oh, Kwang-Joong; Lee, Sang-Sup

    2017-04-01

    The nitrogen oxides (NO x ) reduction technology by combustion modification which has economic benefits as a method of controlling NO x emitted in the combustion process, has recently been receiving a lot of attention. Especially, the moderate or intense low oxygen dilution (MILD) combustion which applied high temperature flue gas recirculation has been confirmed for its effectiveness with regard to solid fuel as well. MILD combustion is affected by the flue gas recirculation ratio and the composition of recirculation gas, so its NO x reduction efficiency is determined by them. In order to investigate the influence of factors which determine the reduction efficiency of NO x in MILD coal combustion, this study changed the flow rate and concentration of nitrogen (N 2 ), carbon dioxide (CO 2 ) and steam (H 2 O) which simulate the recirculation gas during the MILD coal combustion using our lab-scale drop tube furnace and performed the combustion experiment. As a result, its influence by the composition of recirculation gas was insignificant and it was shown that flue gas recirculation ratio influences the change of NO x concentration greatly. We investigated the influence of factors determining the nitrogen oxides (NO x ) reduction efficiency in MILD coal combustion, which applied high-temperature flue gas recirculation. Using a lab-scale drop tube furnace and simulated recirculation gas, we conducted combustion testing changing the recirculation gas conditions. We found that the flue gas recirculation ratio influences the reduction of NO x emissions the most.

  20. INFLUENCE OF SLUDGE RECIRCULATION ON NUTRIENT REMOVAL IN SUBMERGED MEMBRANE BIOREACTORS

    Directory of Open Access Journals (Sweden)

    María Casamitjanaa Causa

    2015-06-01

    Full Text Available Membrane bioreactors (MBR technology is a well-developed wastewater treatment process; however, the integrated operation between biological reactions and physical filtration has been poorly studied. Among other operational parameters, optimal control of sludge recirculation can enhance nitrogen and phosphorous removal processes, but the effects on sludge filterability is not clear. In this paper, different recirculation flow rates were tested to evaluate consequences on sludge filterability and nutrient removal in a MBR-UCT pilot plant treating real municipal wastewater. Three distinct sludge recirculation flows were studied during 10 weeks [external recirculation (from the membrane tank to the anoxic reactor, anoxic recirculation (from the aerobic to the anoxic reactor and anaerobic recirculation (from the anoxic to the anaerobic reactor]. The obtained results have shown that anaerobic recirculation affected nutrient removal in an inversely proportional way, whereas anoxic recirculation had a directly proportional effect. Referring sludge characteristics, filterability and capillarity suction time (CST remained independent of sludge recirculation, whereas CST is proportional to transmembrane pressure (TMP, which seems to depend on external and anoxic sludge recirculation.

  1. Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air

    Science.gov (United States)

    Jung, Heejung S.; Grady, Michael L.; Victoroff, Tristan; Miller, Arthur L.

    2017-07-01

    Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO2 accumulation.

  2. Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air.

    Science.gov (United States)

    Jung, Heejung S; Grady, Michael L; Victoroff, Tristan; Miller, Arthur L

    2017-07-01

    Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO 2 ) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO 2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm 3 , although CO 2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO 2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm 3 . We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO 2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO 2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO 2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO 2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO 2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO 2 accumulation.

  3. The design of trickling biological periwinkle shells filter for closed ...

    African Journals Online (AJOL)

    ... water quality parameters such as DO, pH, temperature, BOD5, Seechi transparency, total alkalinity, free carbon dioxide, chloride, etc. in the treatment system were not significantly (p>0.05) different from that of the control system. We concluded that periwinkle shell is a suitable trickling filter medium for closed recirculation ...

  4. Energy efficient powder production by closed-loop spray drying

    NARCIS (Netherlands)

    Moejes, S.N.; Visser, Quirien; Boxtel, van A.J.B.

    2016-01-01

    Closed-loop dryers are able to reduce the energy consumption in milk powder production up to 60% compared to current practice. Application of monodisperse droplet atomizers eliminates the presence of fines in the exhaust air of spray dryers. It allows the recirculation of the exhaust air over the

  5. Close Air Support versus Close Combat Attack

    Science.gov (United States)

    2012-12-06

    consequence when discussing the two different processes of close air support and close combat attack. This section focuses on service culture. Understanding...According to a RAND study written by Carl Builder, the Air Force “could be said to worship at the altar of technology.”67 These are not what Hofstede...characteristics that are highly prized in a culture and thus serve as models for behavior,” people like Billy Mitchell, Hap Arnold, Tooey Spaatz to name a

  6. Energy balance affected by electrolyte recirculation and operating modes in microbial fuel cells.

    Science.gov (United States)

    Jacobson, Kyle S; Kelly, Patrick T; He, Zhen

    2015-03-01

    Energy recovery and consumption in a microbial fuel cell (MFC) can be significantly affected by the operating conditions. This study investigated the effects of electrolyte recirculation and operation mode (continuous vs sequence batch reactor) on the energy balance in a tubular MFC. It was found that decreasing the anolyte recirculation also decreased the energy recovery. Because of the open environment of the cathode electrode, the catholyte recirculation consumed 10 to 50 times more energy than the anolyte recirculation, and resulted in negative energy balances despite the reduction of the anolyte recirculation. Reducing the catholyte recirculation to 20% led to a positive energy balance of 0.0288 kWh m(-3). The MFC operated as a sequence batch reactor generated less energy and had a lower energy balance than the one with continuous operation. Those results encourage the further development of MFC technology to achieve neutral or even positive energy output.

  7. Disinfection of Pythium-infested recirculation water by UV-oxidation technology.

    Science.gov (United States)

    Runia, W T; Boonstra, S

    2001-01-01

    Selective disinfection against Pythium aphanidermatum in recirculation water was tested with UV-irradiation and with UV-oxidation technology with the objective to reduce the electrical energy consumption per cubic meter treated water. UV-oxidation technology is based on injection of hydrogen peroxide in recirculation water, just before passage along a UV-lamp, thus creating hydroxyl radicals. Pythium aphanidermatum was applied artificially to recirculation water from tomatoes, grown, in rockwool and coconut fibre. Other parameters in this study were pH and transmission value (T10) of the infested recirculation water. Results indicated that the recommended UV-C dose of 100 mJ/cm2 for elimination of fungal pathogens in general can be lowered in case recirculation water is infected with Pythium aphanidermatum only. When UV-oxidation technology was applied with 1 mmol hydrogen peroxide per litre recirculation water, the UV-C dose could be reduced even more in comparison with merely UV irradiation.

  8. Cultural

    Science.gov (United States)

    Wilbur F. LaPage

    1971-01-01

    A critical look at outdoor recreation research and some underlying premises. The author focuses on the concept of culture as communication and how it influences our perception of problems and our search for solutions. Both outdoor recreation and science are viewed as subcultures that have their own bodies of mythology, making recreation problems more difficult to...

  9. The integration of microalgae photobioreactors in a recirculation system for low water discharge mariculture

    OpenAIRE

    Kube, Nicole

    2006-01-01

    In this thesis a potential conceptual design of a recirculation system not only with water processing but also with an enhanced nutrient recycling is presented. The underlying principle of the recirculation system was based on that of an artificial ecosystem and combined several trophic levels (fish, macroalgae, microalgae, worms) (MARE = Marine Artificial Recirculated Ecosystem). The main goal of this thesis was the development of a continuous photobioreactor system for cultivation of Nannoc...

  10. Discussion of the effects of recirculating exhaust air on performance and efficiency of a typical microturbine

    International Nuclear Information System (INIS)

    De Paepe, Ward; Delattin, Frank; Bram, Svend; De Ruyck, Jacques

    2012-01-01

    This paper reports on a specific phenomenon, noticed during steam injection experiments on a microturbine. During the considered experiments, measurements indicated an unsteady inlet air temperature of the compressor, resulting in unstable operation of the microturbine. Non-continuous exhaust air recirculation was a possible explanation for the observed behaviour of the microturbine. The aim of this paper is to investigate and demonstrate the effects of exhaust recirculation on a microgasturbine. Depending on wind direction, exhaust air re-entered the engine, resulting in changing inlet conditions which affects the operating regime of the microturbine. For this paper, a series of experiments were performed in the wind tunnel. These series of experiments allowed investigation of the effect of the wind direction on flue gasses flow. Next to the experiments, steady-state simulations of exhaust recirculation were performed in order to study the effect of exhaust recirculation on thermodynamic performance of the microturbine. Dynamic simulations of the non-continuous recirculation revealed the effects of frequency and amplitude on average performance and stability. Results from simulations supported the important impact of exhaust recirculation. Wind tunnel tests demonstrated the influence of the wind direction on recirculation and revealed the necessity to heighten the stack, thus preventing exhaust recirculation. -- Highlights: ► Unstable operation of a T100 microturbine during steam injection tests was noticed, caused by exhaust gas recirculation. ► Wind tunnel tests were performed to study the effect of the wind direction on the recirculation process. ► Steady-state simulations to investigate the effect of exhaust gas recirculation on thermodynamic performance. ► Dynamic simulations to reveal effects of frequency and amplitude on average performance and stability. ► Wind tunnel tests revealed the necessity to heighten the stack to prevent exhaust

  11. Sex, violence and HIV on the inside: cultures of violence, denial, gender inequality and homophobia negatively influence the health outcomes of those in closed settings.

    Science.gov (United States)

    Kelly-Hanku, Angela; Kawage, Thomas; Vallely, Andrew; Mek, Agnes; Mathers, Bradley

    2015-01-01

    To map the context of HIV in closed settings in Papua New Guinea (PNG), semi-structured interviews were undertaken with 56 prisoners and detainees and 60 key stakeholders. The nature of HIV-related risk differs for detained women and men, and reflects important gender-based issues present in PNG society more broadly. Women in detention are vulnerable to sexual violence and exploitation and at greatest risk of HIV while detained in police holding cells, where they are typically supervised by male officers, in contrast to prisons, where they have little contact with male staff. HIV risk for men in prison is associated with consensual and non-consensual sex; this risk is perpetuated by a pervasive culture of denial and institutionalised homophobia. The illegal nature of sodomy and male-to-male sex provides Correctional Services the legal grounds by which to refuse access to condoms for prisoners. Addressing HIV risk among detained men and women in PNG requires the reform of legislation, police and prison practices and an understanding of broader structural problems of gender-based violence and stigma and discrimination.

  12. Applying rotary jet heads for mixing and mass transfer in a forced recirculation tank reactor system

    DEFF Research Database (Denmark)

    Nordkvist, Mikkel; Grotkjær, Thomas; Hummer, J.S.

    2003-01-01

    An approximation to an ideally mixed tank reactor can be obtained by vigorous stirring with mechanical mixers. For an aerated reactor the gas dispersion contributes to the mixing process. Mixing can also be achieved by recirculation of a portion of the liquid through either an internal...... at 1-9 bar gauge pressure into the bulk liquid. Liquid feed can be added to the bulk volume or it may be injected into the pressurized recirculation loop. Gas is always fed to the recirculation loop, and the heat of reaction is removed in a plate-type heat exchanger inserted in the recirculation loop...

  13. Numerical analysis of biomass torrefaction reactor with recirculation of heat carrier

    Science.gov (United States)

    Director, L. B.; Ivanin, O. A.; Sinelshchikov, V. A.

    2018-01-01

    In this paper, results of numerical analysis of the energy-technological complex consisting of the gas piston power plant, the torrefaction reactor with recirculation of gaseous heat carrier and the heat recovery boiler are presented. Calculations of the reactor without recirculation and with recirculation of the heat carrier in torrefaction zone at different frequencies of unloading of torrefied biomass were held. It was shown that in recirculation mode the power of the gas piston power plant, required for providing given reactor productivity, is reduced several times and the consumption of fuel gas, needed for combustion of volatile torrefaction products in the heat recovery boiler, is reduced by an order.

  14. Successful Electron Beam Recirculation Test for Fermilab Electron Cooling

    Science.gov (United States)

    Nagaitsev, Sergei; Crawford, A. Curtis; Sharapa, Anatoly; Shemyakin, Alexander

    1998-04-01

    In this paper we describe the successful operation of a dc recirculation electron beam system at energies 1 -- 1.5 MeV and currents in excess of 200 mA. This system employs an electrostatic HV supply like a Van de Graaff generator with maximum charging current of a few hundred microamps. Electron beam line consits of a 10 m long channel with discrete focusing elements flanked by high-gradient (10 kV/cm), small aperture (2.54 cm ID) acceleraton and deceleration tubes. This work is performed as part of the Fermilab R&D program to develop electron cooling for 8 GeV antiprotons.

  15. Gun and optics calculations for the Fermilab recirculation experiment

    International Nuclear Information System (INIS)

    Kroc, T.

    1997-10-01

    Fermilab is investigating electron cooling to recycle 8 Gev antiprotons recovered from the Tevatron. To do so, it is developing an experiment to recirculate 2 Mev electrons generated by a Pelletron at National Electrostatics Corporation. This paper reports on the optics calculations done in support of that work. We have used the computer codes EGN2 and MacTrace to represent the gun area and acceleration columns respectively. In addition to the results of our simulations, we discuss some of the problems encountered in interfacing the two codes

  16. Commercial production of tiger puffer ( Takifugu rubripes) in winter using a recirculating aquaculture system

    Science.gov (United States)

    Lin, Zhongling; Wang, Hua; Yu, Chunyan; Lv, Fenghe; Liu, Hengming; Zhang, Tao

    2017-02-01

    Tiger puffer ( Takifugu rubripes) is a promising species for aquaculture production because of its high value and limited supply. However, in the north of China, using sea cages to culture this species in winter is hampered by the fact that the seawater temperature is extremely low. Here, a large scale commercial production of tiger puffer has been successfully realized using a recirculating aquaculture system (RAS) from 3 October 2012 to 31 May 2013. The RAS was comprised of nine culture tanks (total water volume 200 m3) and stocked with approximately a total of 14400 fish (initial mean weight 160 g). The tiger puffer was hand-fed at a rate of 0.7% of total body weight per day, and the feed conversion rate was (1.21 ± 0.3) kg kg-1. The recycle water in RAS was treated by a sieve bend screen, a foam fractionator, a submerged biofilter, an UV sterilizer and a submersible aerator. During the whole culture period, an excellent water quality control was achieved in RAS. At the end of this experiment, the survival rate of tiger puffer was more than 98%. The final tank densities averaged 31.2 kg m-3, and the final individual mean weight was 440 g.

  17. cultural

    Directory of Open Access Journals (Sweden)

    Irene Kreutz

    2006-01-01

    Full Text Available Es un estudio cualitativo que adoptó como referencial teorico-motodológico la antropología y la etnografía. Presenta las experiencias vivenciadas por mujeres de una comunidad en el proceso salud-enfermedad, con el objetivo de comprender los determinantes sócio-culturales e históricos de las prácticas de prevención y tratamiento adoptados por el grupo cultural por medio de la entrevista semi-estructurada. Los temas que emergieron fueron: la relación entre la alimentación y lo proceso salud-enfermedad, las relaciones con el sistema de salud oficial y el proceso salud-enfermedad y lo sobrenatural. Los dados revelaron que los moradores de la comunidad investigada tienen un modo particular de explicar sus procedimientos terapéuticos. Consideramos que es papel de los profesionales de la salud en sus prácticas, la adopción de abordajes o enfoques que consideren al individuo en su dimensión sócio-cultural e histórica, considerando la enorme diversidad cultural en nuestro país.

  18. Power plant including an exhaust gas recirculation system for injecting recirculated exhaust gases in the fuel and compressed air of a gas turbine engine

    Science.gov (United States)

    Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy; Shaffer, Jason Brian; York, William David

    2014-05-13

    A power plant is provided and includes a gas turbine engine having a combustor in which compressed gas and fuel are mixed and combusted, first and second supply lines respectively coupled to the combustor and respectively configured to supply the compressed gas and the fuel to the combustor and an exhaust gas recirculation (EGR) system to re-circulate exhaust gas produced by the gas turbine engine toward the combustor. The EGR system is coupled to the first and second supply lines and configured to combine first and second portions of the re-circulated exhaust gas with the compressed gas and the fuel at the first and second supply lines, respectively.

  19. Microwave Power Measurements on the Recirculating Planar Magnetron

    Science.gov (United States)

    Jordan, N. M.; Franzi, M.; Greening, G. B.; Gilgenbach, R. M.; Simon, D. H.; Lau, Y. Y.; Hoff, B. W.; Luginsland, J. W.

    2014-10-01

    The recirculating planar magnetron (RPM) is a high power microwave generator that recirculates the beam in two-coupled, planar magnetrons. Experiments on the first L-band prototype have successfully produced 50--200 μs, 30-130 MW microwave pulses with instantaneous electronic efficiencies of up to 30% at approximately 1 GHz. The device is driven using MELBA-C, with parameters of: -300 kV for 0.3-1.0 μs, and 0.15-0.3 T axial magnetic fields. Recent RPM experiments have explored the effect of cathode surface treatment on the extracted microwave power, efficiency, and pulse width. This work utilized a proof of principle extraction system with antennas on the center vane of each oscillator to couple RF power into two, coaxial transmission lines. An advanced design, the Coaxial All Cavity Extractor, is in fabrication and will be discussed. Research supported by AFOSR Grant #FA9550-10-1-0104 and by AFRL.

  20. Control methodologies based on geothermal recirculating aquaculture system

    International Nuclear Information System (INIS)

    Farghally, Hanaa M.; Atia, Doaa M.; El-madany, Hanaa T.; Fahmy, Faten H.

    2014-01-01

    One of the most common uses of geothermal heat is in RAS (recirculation aquaculture systems) where the water temperature is accurately controlled for optimum growing conditions for sustainable and intensive rearing of marine and freshwater fish. This paper presents a design for RAS rearing tank and plate type heat exchanger to be used with geothermal energy as a source of heating water. A well at Umm Huweitat on the Red Sea is used as a source of geothermal energy. The heat losses from the RAS tank are calculated using Geo Heat Center Software. Then a plate type heat exchanger is designed using the epsilon–NTU (number of transfer units) analysis method. For optimal growth and abundance of production, a different techniques of control system are applied to control the water temperature. The total system is built in MATLAB/SIMULINK to study the overall performance of control unit. Finally, a comparison between PI, Fuzzy-PID, and Fuzzy Logic Control has been done. - Highlights: • Design recirculating aquaculture system using geothermal energy. • Design a PI controller for water temperature control. • Design a Fuzzy logic controller for water temperature control. • Design a Fuzzy-PID controller for water temperature control. • Comparison between different control systems

  1. Effect of irradiation on nonlinear optical recirculation cavity performance

    Energy Technology Data Exchange (ETDEWEB)

    Saitta, M. [Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15289 (United States); Tikhoplav, R. [RadiaBeam Technologies, Santa Monica, CA 90404 (United States); Jovanovic, I., E-mail: ijovanovic@psu.edu [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2012-02-01

    In applications such as the production of hydrogen ions for accelerators in spallation neutron sources, charge stripping of hydrogen ions using high-power lasers represents an attractive technical approach. The use of laser-ion interaction in conjunction with a laser recirculation cavity holds promise for improved efficiency, but the high-radiation environment raises concerns about the longevity of the key components of such a system, especially the nonlinear crystal used for frequency conversion. We present the results of an in-reactor irradiation experiment in which a sample beta-barium borate crystal has been irradiated with fast neutrons and gamma-rays, accompanied with the Monte Carlo analysis of the irradiation dose and its comparison with typical conditions at the Spallation Neutron Source at Oak Ridge National Laboratory. The results suggest that our design of the laser recirculation cavity exhibits a radiation hardness consistent with maintaining enhancement factors of the order of 10 over >10 years, but a more detailed experimental study is needed to investigate the radiation hardness of cavity designs exhibiting greater enhancement factors.

  2. Electricity generation using continuously recirculated flow electrodes in reverse electrodialysis

    Science.gov (United States)

    Liu, Fei; Coronell, Orlando; Call, Douglas F.

    2017-07-01

    Capacitive flow electrode systems that generate electricity from salinity gradients are limited by low power densities, inefficient electrical current collection, and complex system operation. We show here the proof-of-concept that a single reverse electrodialysis cell using continuously recirculated activated carbon flow electrodes can generate uninterrupted electricity from an artificial sea/river water gradient. Power densities reached 61 ± 5.7 mW m-2 (normalized to total membrane surface area) and current densities 2.4 ± 0.13 A m-2 when a 10% by weight carbon loading was used with graphite plate current collectors. Using high-surface area graphite brush current collectors, maximum power densities increased more than 320% to 260 ± 8.7 mW m-2 and maximum current densities more than 400% to 14 ± 0.59 A m-2. The performance improvements were attributed to a more than 80% decrease in electrode resistances when brushes were used instead of plates. A control static capacitive electrode system obtained slightly higher average power densities (290 ± 8.7 mW m-2), but could not produce it continuously, highlighting the operational advantage of the recirculated flow electrode design.

  3. Designing and Testing of Self-Cleaning Recirculating Zebrafish Tanks.

    Science.gov (United States)

    Nema, Shubham; Bhargava, Yogesh

    2016-08-01

    Maintenance of large number of zebrafish in captive conditions is a daunting task. This can be eased by the use of recirculating racks with self-cleaning zebrafish tanks. Commercially available systems are costly, and compatibility of intercompany products has never been investigated. Although various cost-effective designs and methods of construction of custom-made recirculating zebrafish racks are available in literature, the design of self-cleaning zebrafish tanks is still not available. In this study, we report the design and method of construction of the self-cleaning unit, which can be fitted in any zebrafish tank. We validated the design by investigating sediment cleaning process in rectangular and cylindrical tank geometries using time lapse imaging. Our results suggest that for both tank geometries, the tanks fitted with self-cleaning unit provided superior sediment cleaning than the tanks fitted with overflow-drain unit. Although the self-cleaning unit could clean the sediment completely from both geometries over prolonged period, the cleaning of sediments was faster in the cylindrical tank than the rectangular tank. In conclusion, cost and efforts of zebrafish maintenance could be significantly reduced through the installation of our self-cleaning unit in any custom-made zebrafish tank.

  4. Continuous hydroponic wheat production using a recirculating system

    Science.gov (United States)

    Mackowiak, C. L.; Owens, L. P.; Hinkle, C. R.; Prince, R. P.

    1989-01-01

    Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

  5. RESEARCHES REGARDING THE TECHNOLOGICAL PERFORMANCES OF CARP REARING DURING WINTER PERIOD IN THE CONDITIONS OF A RECIRCULATING AQUACULTURE SYSTEM

    Directory of Open Access Journals (Sweden)

    G. STEFAN

    2008-10-01

    Full Text Available The techniques of carp culture are highly diversified, ranging from the extensive production in pond or open water with no fertilization or supplemental feeding to highly intensive systems in concrete tanks or cages. Among the different carp species, common carp is the best species reared in intensive monoculture, the others (Chinese and Indian carps being usually cultivated in polyculture (P. Kestemont, 1995. An experiment was conducted in inside recirculation system conditions to identify the technological performances on carp growth and survival at the Fishing and Aquaculture Department, Galati, during winter period (February, 2007 – March, 2007. The 1-year-old carp (Cyprinus carpio 4792g; 4594 g; 4561 g and 4525 g (total weight grew to 7384g; 7017g; 6924g and 7125 g in 44 days in aquarium 1, 2, 3 and 4, respectively. In all aquariums, the fish appeared healthy and no mortality was observed. Feed conversion efficiencies (FCE had similar values among all aquariums, the highest FCE being found in B4 aquarium with 1, 57 value. Water quality parameters were acceptable range for fish culture. Results show that the carp rearing during winter period in the inside recirculation system is a very good economic solution.

  6. Conditioning of broodstock of tiger grouper, Epinephelus fuscoguttatus, in a recirculating aquaculture system

    Directory of Open Access Journals (Sweden)

    Saleem Mustafa

    2015-11-01

    Full Text Available Closing the cycle of commercial species of fish in a recirculating aquaculture system is gaining importance for a number of practical advantages. Founder broodstock originating from the wild population is conditioned to live in hatchery tanks under suitable environmental and feeding conditions and is induced to breed. The juveniles are grown to maturity and facilitated to spawn in captivity to close the life cycle in the hatchery. This experiment was carried out on tiger grouper (Epinephelus fuscoguttatus. After preliminary observations, it was possible to identify appropriate environmental conditions in terms of water quality parameters, volume of broodstock tanks and ration. Growth was nearly isometric (growth exponent = 2.9185 and the condition factor = 1.86. This reflected good management conditions. Cues that trigger sex reversal in this protogynous fish in the hatchery were different from those that operate in nature. It appears that the differentiation of some individuals of a cohort into male sex is linked to socio-demographic cues as well as internal condition of the fish because it related to age and physiological condition. This view was reinforced by a lack of response in young fish to similar cues. The information generated through this study defines what is required for optimum conditioning of tiger grouper broodstock and explains the cues involved in sex differentiation.

  7. Daily micro particle distribution of an experimental recirculating aquaculture system – A case study

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2014-01-01

    The particle size distribution (PSD) in a recirculating aquaculture system (RAS) was investigated duringa 24-h cycle. PSD was analyzed in water sampled at several locations in a recirculation loop containing a60-m drum filter, a submerged fixed-bed biofilter and a trickling filter.In relation...

  8. Does an Open Recirculation Line Affect the Flow Rate and Pressure in a Neonatal Extracorporeal Life Support Circuit With a Centrifugal or Roller Pump?

    Science.gov (United States)

    Wang, Shigang; Spencer, Shannon B; Woitas, Karl; Glass, Kristen; Kunselman, Allen R; Ündar, Akif

    2017-01-01

    The objective of this study is to evaluate the impact of an open or closed recirculation line on flow rate, circuit pressure, and hemodynamic energy transmission in simulated neonatal extracorporeal life support (ECLS) systems. The two neonatal ECLS circuits consisted of a Maquet HL20 roller pump (RP group) or a RotaFlow centrifugal pump (CP group), Quadrox-iD Pediatric oxygenator, and Biomedicus arterial and venous cannulae (8 Fr and 10 Fr) primed with lactated Ringer's solution and packed red blood cells (hematocrit 35%). Trials were conducted at flow rates ranging from 200 to 600 mL/min (200 mL/min increments) with a closed or open recirculation line at 36°C. Real-time pressure and flow data were recorded using a custom-based data acquisition system. In the RP group, the preoxygenator flow did not change when the recirculation line was open while the prearterial cannula flow decreased by 15.7-20.0% (P pump, but did not change perfusion flow in the circuit using a centrifugal pump. An additional flow sensor is needed to monitor perfusion flow in patients if any shunts exist in the ECLS circuit. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  9. Modeling of leachate recirculation using combined drainage blanket-horizontal trench systems in bioreactor landfills.

    Science.gov (United States)

    Feng, Shi-Jin; Cao, Ben-Yi; Xie, Hai-Jian

    2017-10-01

    Leachate recirculation in municipal solid waste (MSW) landfills operated as bioreactors offers significant economic and environmental benefits. Combined drainage blanket (DB)-horizontal trench (HT) systems can be an alternative to single conventional recirculation approaches and can have competitive advantages. The key objectives of this study are to investigate combined drainage blanket -horizontal trench systems, to analyze the effects of applying two recirculation systems on the leachate migration in landfills, and to estimate some key design parameters (e.g., the steady-state flow rate, the influence width, and the cumulative leachate volume). It was determined that an effective recirculation model should consist of a moderate horizontal trench injection pressure head and supplementary leachate recirculated through drainage blanket, with an objective of increasing the horizontal unsaturated hydraulic conductivity and thereby allowing more leachate to flow from the horizontal trench system in a horizontal direction. In addition, design charts for engineering application were established using a dimensionless variable formulation.

  10. Removal of polycyclic aromatic hydrocarbons (PAH) during anaerobic digestion with recirculation of ozonated digested sludge

    International Nuclear Information System (INIS)

    Bernal-Martinez, Arodi; Patureau, Dominique; Delgenes, Jean-Philippe; Carrere, Helene

    2009-01-01

    PAH are particularly monitored because of their carcinogenic properties and their ubiquity in the environment. Their presence in municipal sewage sludge is a major problem due to the environmental risks associated with the sludge spreading on agricultural soils. The objective of this work was to asses the removal of PAH naturally present in sludge by continuous anaerobic digestion with recirculation of ozonated sludge. Recirculation of ozonated digested sludge allowed to enhance PAH removals, the highest efficiency was obtained with the highest ozone dose (0.11 g O 3 /g TS ). In order to study the effect of recirculation, a reactor was operated without recirculation but was fed with a mixture of raw and ozonated digested sludge. This process led to the best performances in terms of PAH and solid removals. This pointed out some accumulation of nonbiodegradable or recalcitrant compounds during recirculation assay. Smallest and most soluble compounds presented the highest biodegradation efficiencies

  11. Recirculation, stagnation and ventilation: The 2014 legionella episode

    Science.gov (United States)

    Russo, Ana; Soares, Pedro M. M.; Gouveia, Célia M.; Cardoso, Rita M.; Trigo, Ricardo M.

    2017-04-01

    Legionella transmission through the atmosphere is unusual, but not unprecedented. A scientific paper published in 2006 reports a surge in Pas-de-Calais, France, in which 86 people have been infected by bacteria released by a cooling tower more than 6 km away [3]. Similarly, in Norway, in 2005, there was another case where contamination spread beyond 10 km, although more concentrated within a radius of 1 km from an industrial unit [2]. An unprecedented large Legionella outbreak occurred in November 2014 nearby Lisbon, Portugal. As of 7 November 2014, 375 individuals become hill and 12 died infected by the Legionella pneumophila bacteria, contracted by inhalation of steam droplets of contaminated water (aerosols). These droplets are so small that can carry the bacteria directly to the lungs, depositing it in the alveoli. One way of studying the propagation of legionella episodes is through the use of aerosol dispersion models. However, such approaches often require detailed 3D high resolution wind data over the region, which isn't often available for long periods. The likely impact of wind on legionella transmission can also be understood based on the analysis of special types of flow conditions such as stagnation, recirculation and ventilation [1, 4]. The Allwine and Whiteman (AW) approach constitutes a straightforward method to assess the assimilative and dispersal capacities of different airsheds [1,4], as it only requires hourly wind components. Thus, it has the advantage of not needing surface and upper air meteorological observations and a previous knowledge of the atmospheric transport and dispersion conditions. The objective of this study is to analyze if the legionella outbreak event which took place in November 2014 had extreme potential recirculation and/or stagnation characteristics. In order to accomplish the proposed objective, the AW approach was applied for a hindcast time-series covering the affected area (1989-2007) and then for an independent

  12. Pulsed-focusing recirculating linacs for muon acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland [Muons, Inc., Batavia, IL (United States)

    2014-12-31

    Since the muon has a short lifetime, fast acceleration is essential for high-energy applications such as muon colliders, Higgs factories, or neutrino factories. The best one can do is to make a linear accelerator with the highest possible accelerating gradient to make the accelerating time as short as possible. However, the cost of such a single linear accelerator is prohibitively large due to expensive power sources, cavities, tunnels, and related infrastructure. As was demonstrated in the Thomas Jefferson Accelerator Facility (Jefferson Lab) Continuous Electron Beam Accelerator Facility (CEBAF), an elegant solution to reduce cost is to use magnetic return arcs to recirculate the beam through the accelerating RF cavities many times, where they gain energy on each pass. In such a Recirculating Linear Accelerator (RLA), the magnetic focusing strength diminishes as the beam energy increases in a conventional linac that has constant strength quadrupoles. After some number of passes the focusing strength is insufficient to keep the beam from going unstable and being lost. In this project, the use of fast pulsed quadrupoles in the linac sections was considered for stronger focusing as a function of time to allow more successive passes of a muon beam in a recirculating linear accelerator. In one simulation, it was shown that the number of passes could be increased from 8 to 12 using pulsed magnet designs that have been developed and tested. This could reduce the cost of linac sections of a muon RLA by 8/12, where more improvement is still possible. The expense of a greater number of passes and corresponding number of return arcs was also addressed in this project by exploring the use of ramped or FFAG-style magnets in the return arcs. A better solution, invented in this project, is to use combined-function dipole-quadrupole magnets to simultaneously transport two beams of different energies through one magnet string to reduce costs of return arcs by almost a factor of

  13. Fuzzy Logic Controller based on geothermal recirculating aquaculture system

    Directory of Open Access Journals (Sweden)

    Hanaa M. Farghally

    2014-01-01

    Full Text Available One of the most common uses of geothermal heat is in recirculation aquaculture systems (RAS where the water temperature is accurately controlled for optimum growing conditions for sustainable and intensive rearing of marine and freshwater fish. This paper presents a design for RAS rearing tank and brazed heat exchanger to be used with geothermal energy as a source of heating water. The heat losses from the RAS tank are calculated using Geo Heat Center Software. Then a plate type heat exchanger is designed using the epsilon – NTU analysis method. For optimal growth and abundance of production, a Fuzzy Logic control (FLC system is applied to control the water temperature (29 °C. A FLC system has several advantages over conventional techniques; relatively simple, fast, adaptive, and its response is better and faster at all atmospheric conditions. Finally, the total system is built in MATLAB/SIMULINK to study the overall performance of control unit.

  14. Exergetic performance analysis of a recirculating aquaculture system

    International Nuclear Information System (INIS)

    Kucuk, Haydar; Midilli, Adnan; Ozdemir, Atilla; Cakmak, Eyuep; Dincer, Ibrahim

    2010-01-01

    This paper examines exergetic aspects of a Recirculation Aquaculture System (RAS) for Black Sea trout (Salmo trutta labrax) fingerling rearing at the Trabzon Central Fisheries Research Institute, Turkey. In its thermodynamic analysis, each component of the RAS is treated as a steady-state steady flow system and its exergetic efficiencies are studied. In addition, the following parameters are measured and recorded in experiments: the mass flow rates, inlet and outlet temperatures and of the system components, surrounding temperatures, and electrical work utilized by the components in the RAS. Based on these experimental data, inlet and outlet exergy values, exergy losses, and exergetic efficiencies of each component in the system are determined to assess their performance. Moreover, the overall system exergy efficiency is determined. The results show that exergy efficiencies of the system components are highly affected by varying input exergy flows as a function of the surrounding temperature and chiller's operating period.

  15. Off-gas recirculation system for nuclear reactors

    International Nuclear Information System (INIS)

    Eppler, M.; Lade, H.J.

    1975-01-01

    According to the invention, it is suggested to provide a buffer vessel in the ring main of the off-gas recirculation system for off-gases of a nuclear reactor to which all chambers or vessels which may contain radioactively contaminated gases are connected, within the connection line to outside air. This is to prevent the immediate release of an appreciable amount of gas to the outside air due to pressure variations conditioned by the sequence of operations - e.g. on the filling of the coolant storage. After the improvement, the released gas may be reduced to the amount of gas corresponding to the leakage gas flow entering the ring mains system. (TK) [de

  16. Dynamics of microorganism populations in recirculating nutrient solutions

    Science.gov (United States)

    Strayer, R. F.

    1994-01-01

    This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet Controlled Ecological Life Support Systems (CELSS) tests and the commercial hydroponic industry will be used. The sources of microorganisms in nutrient solutions include air, water, seeds, plant containers and plumbing, biological vectors, and personnel. Microbial fates include growth, death, and emigration. Important microbial habitats within nutrient delivery systems are root surfaces, hardware surfaces (biofilms), and solution suspension. Numbers of bacteria on root surfaces usually exceed those from the other habitats by several orders of magnitude. Gram negative bacteria dominate the microflora with fungal counts usually much lower. Trends typically show a decrease in counts with increasing time unless stressed plants increase root exudates. Important microbial activities include carbon mineralization and nitrogen transformations. Important detrimental interactions include competition with plants, and human and plant pathogenesis.

  17. Recycling crop residues for use in recirculating hydroponic crop production

    Science.gov (United States)

    Mackowiak, C. L.; Garland, J. L.; Sager, J. C.

    1996-01-01

    As part of bioregenerative life support feasibility testing by NASA, crop residues are being used to resupply elemental nutrients to recirculating hydroponic crop production systems. Methods for recovering nutrients from crop residues have evolved from water soaking (leaching) to rapid aerobic bioreactor processing. Leaching residues recovered the majority of elements but it also recovered significant amounts of soluble organics. The high organic content of leachates was detrimental to plant growth. Aerobic bioreactor processing reduced the organic content ten-fold, which reduced or eliminated phytotoxic effects. Wheat and potato production studies were successful using effluents from reactors having with 8- to 1-day retention times. Aerobic bioreactor effluents supplied at least half of the crops elemental mass needs in these studies. Descriptions of leachate and effluent mineral content, biomass productivity, microbial activity, and nutrient budgets for potato and wheat are presented.

  18. Recirculation of the Canary Current in fall 2014

    Science.gov (United States)

    Hernández-Guerra, Alonso; Espino-Falcón, Elisabet; Vélez-Belchí, Pedro; Dolores Pérez-Hernández, M.; Martínez-Marrero, Antonio; Cana, Luis

    2017-10-01

    Hydrographic measurements together with Ship mounted Acoustic Doppler Current Profilers and Lowered Acoustic Doppler Current Profilers (LADCP) obtained in October 2014 are used to describe water masses, geostrophic circulation and mass transport of the Canary Current System, as the Eastern Boundary of the North Atlantic Subtropical Gyre. Geostrophic velocities are adjusted to velocities from LADCP data to estimate an initial velocity at the reference layer. The adjustment results in a northward circulation at the thermocline layers over the African slope from an initial convergent flow. Final reference velocities and consequently absolute circulation are estimated from an inverse box model applied to an ocean divided into 13 neutral density layers. This allows us to evaluate mass fluxes consistent with the thermal wind equation and mass conservation. Ekman transport is estimated from the wind data derived from the Weather Research and Forecasting model. Ekman transport is added to the first layer and adjusted with the inverse model. The Canary Current located west of Lanzarote Island transports to the south a mass of - 1.5 ± 0.7 Sv (1 Sv = 106 m3 s- 1 ≈ 109 kg s- 1) of North Atlantic Central Water at the surface and thermocline layers ( 0-700 m). In fall 2014, hydrographic data shows that the Canary Current in the thermocline (below at about 80 m depth to 700 m) recirculates to the north over the African slope and flows through the Lanzarote Passage. At intermediate layers ( 700-1400 m), the Intermediate Poleward Undercurrent transports northward a relatively fresh Antarctic Intermediate Water in the range of 0.8 ± 0.4 Sv through the Lanzarote Passage and west of Lanzarote Island beneath the recirculation of the Canary Current.

  19. "A Tale of Two Programs": Interrogating "Open(closed)ness" and "Cultural Diversity" through Critical Observations of Two Japanese University English Language Programs

    Science.gov (United States)

    Toh, Glenn

    2015-01-01

    Japan is known to be a country that manicures its socio-cultural borders. In this article I will examine discourses regarding openness, closedness and cultural diversity in relation to policies and practices that draw heavily on mythologies of English language as an inroad to greater openness and diversity. To do this I will examine two English…

  20. Simultaneous methanogenesis and denitrification of aniline wastewater by using anaerobic-aerobic biofilm system with recirculation

    International Nuclear Information System (INIS)

    Chen Sheng; Sun Dezhi; Chung, Jong-Shik

    2009-01-01

    Wastewater containing highly concentrated nitrogenous and aromatic compounds, such as aniline, is difficult to degrade and very toxic to microorganisms, especially to nitrifier. In order to remove both carbon and nitrogen from aniline wastewater, recently two biofilm reactors equipped with anaerobic-aerobic cycle and internal recirculation have demonstrated some potential in treating the wastewater. In such system, ammonification, methanogenesis and denitrification reactions occurred simultaneously in one anaerobic reactor, followed by COD removal and nitrification in the aerobic reactor. The effect of recirculation ratio on COD and nitrogen removal using such reactor arrangement was therefore investigated in the present work. The results showed that recirculation had little impact on the overall COD removal or denitrification activity in the anaerobic reactor at any tested ratio, 96-98% of overall COD removal efficiency was achieved with a final effluent COD value below 200 mg/L. But nitrification and TN removal were strongly affected by recirculation. The nitrification rate reached a maximum of 0.48 kg N/(m 3 d) at recirculation ratio of 1 and complete nitrification was achieved at the recirculation ratios over 2. TN removal efficiency increased continuously and a sharp reduction of sludge production in the system was observed with increasing recirculation.

  1. Transition from the recycle to the recirculation based society. Development of hydrothermally solidified soil / earth ceramics; Recycle kara recirculation e. Tsuchi no suinetsukokatai / soil ceramics no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, H. [INAX Corp., Aichi (Japan)

    1998-07-25

    A recirculation type society is indispensable to establish a durable society. The conventional society that exploits law materials from the nature and throws them back is condemned and a fundamental idea of using soil as a building material and the development of hydrothermally solidified soil that the author has been flinging himself since 1992 are introduced. The soil is solidified at temperatures below 200degC and used as earth ceramics which is returned to the natural ecological system when it is disposed. In the case of earth ceramics produced by INAX Co., A production line has been set up as a closed system where 80% of the waste disposal in volume was cut since 1992 and the exhaust of CO2 was cut 12% in volume as compared to that of 1996. Details of the hydrothermal technique development as well as the mineral composition in respect to various properties of the earth ceramics are examined. It is proved that the latter has a bending strength of 4 to 6MPa that is equal to that of the concrete and the humidity regulatory property equal to that of wood. The solidified soil has actually been applied to a floor area about 35m{sup 2} of a living room in a highly air-proof apartment house and one year later, experimental results are obtained about its regulatory properties in terms of seasonal temperature and humidity variations, together with its favorable effect for controlling proliferation of Acarina and other living organisms. 27 refs., 11 figs., 2 tabs.

  2. Sulfur recirculation for increased electricity production in Waste-to-Energy plants.

    Science.gov (United States)

    Andersson, Sven; Blomqvist, Evalena W; Bäfver, Linda; Jones, Frida; Davidsson, Kent; Froitzheim, Jan; Karlsson, Martin; Larsson, Erik; Liske, Jesper

    2014-01-01

    Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop. The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion. In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60-90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Long term/low dose formalin exposure to small-scale recirculation aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg; Nielsen, Jeppe L.

    2010-01-01

    Repetitive long term formalin application at low dose was investigated to determine the effect on formaldehyde removal rate, biofilter nitrification and the microbial composition in small-scale recirculation aquaculture biofilters. Six pilot-scale recirculation aquaculture systems holding rainbow...... Nitrobacter sp. was not detected. The relative abundances of AOB and NOB in the untreated system were generally higher compared to the system exposed to formalin. Low dose formalin in recirculated aquaculture systems proved to be a possible treatment strategy, as the effect on nitrification was minimal. Since...

  4. A polarimeter for GeV protons of recirculating synchrotron beams

    CERN Document Server

    Bauer, F

    1999-01-01

    A polarimeter for use in recirculating beams of proton synchrotrons with energies from 300 MeV up to several GeV has been developed. The polarimetry is based on the asymmetry measurement of elastic p->p scattering on an internal CH sub 2 fiber target. The forward going protons are detected with two scintillator systems on either side of the beam pipe close to the angle THETA sub f of maximum analyzing power A sub N. Each one operates in coincidence with a broad (DELTA THETA sub b =21.4 deg. ), segmented detector system for the recoil proton of kinematically varying direction THETA sub b; this position resolution is also used for a concurrent measurement of the p->C and nonelastic p->p background. The CH sub 2 fiber can be replaced by a carbon fiber for detailed background studies; 'false' asymmetries are accounted for with a rotation of the polarimeter around the beam axis. Polarimetry has been performed in the internal beam of the Cooler Synchrotron COSY at fixed energies as well as during proton acceleratio...

  5. Surrogate Model for Recirculation Phase LBLOCA and DET Application

    International Nuclear Information System (INIS)

    Fynan, Douglas A; Ahn, Kwang-Il; Lee, John C.

    2014-01-01

    In the nuclear safety field, response surfaces were used in the first demonstration of the code scaling, applicability, and uncertainty (CSAU) methodology to quantify the uncertainty of the peak clad temperature (PCT) during a large-break loss-of-coolant accident (LBLOCA). Surrogates could have applications in other nuclear safety areas such as dynamic probabilistic safety assessment (PSA). Dynamic PSA attempts to couple the probabilistic nature of failure events, component transitions, and human reliability to deterministic calculations of time-dependent nuclear power plant (NPP) responses usually through the use of thermal-hydraulic (TH) system codes. The overall mathematical complexity of the dynamic PSA architectures with many embedded computational expensive TH code calculations with large input/output data streams have limited realistic studies of NPPs. This paper presents a time-dependent surrogate model for the recirculation phase of a hot leg LBLOCA in the OPR-1000. The surrogate model is developed through the ACE algorithm, a powerful nonparametric regression technique, trained on RELAP5 simulations of the LBLOCA. Benchmarking of the surrogate is presented and an application to a simplified dynamic event tree (DET). A time-dependent surrogate model to predict core subcooling during the recirculation phase of a hot leg LBLOCA in the OPR-1000 has been developed. The surrogate assumed the structure of a general discrete time dynamic model and learned the nonlinear functional form by performing nonparametric regression on RELAP5 simulations with the ACE algorithm. The surrogate model input parameters represent mass and energy flux terms to the RCS that appeared as user supplied or code calculated boundary conditions in the RELAP5 model. The surrogate accurately predicted the TH behavior of the core for a variety of HPSI system performance and containment conditions when compared with RELAP5 simulations. The surrogate was applied in a DET application replacing

  6. Association between trichodiniasis in eel ( Anguilla anguilla ) and water quality in recirculation systems

    DEFF Research Database (Denmark)

    Madsen, H.C.K.; Buchmann, K.; Mellergaard, Stig

    2000-01-01

    Association between various water quality parameters and the infection level of Trichodina jadranica in cultured eels were examined in nine recirculation farms in Denmark. Production units suffering from trichodiniasis (n = 4) had relatively high contents of organic dry matter (13-65 mg l(-1)), low...... concentrations of nitrate (150-500 mg NO3 l(-1)) and high pH (6.2-7.4) in the process water compared to farms without Trichodina problems (n = 5), which had a relatively low load of organic dry matter (9-16 mg l(-1)), high nitrate concentration (250-900 mg NO3 l(-1)) and a low pH (5.3-6.9). More detailed studies...... of the effect of water parameters on the infection level were conducted in two production units suffering from frequent outbreaks of trichodiniasis. In one production unit, the high and highly varying content of organic dry matter (21- 83 mg l(-1)) was significantly and positively correlated (r = 0.37, p

  7. Chemical decontamination of Santa Maria de Garona NPP recirculation loops

    International Nuclear Information System (INIS)

    Coello, R.

    2002-01-01

    Santa Maria de Garona is a boiling water reactor (BWR-3) with a Primary Containment type Mark 1. Its electrical power is 466 Mw and began its commercial operation in 1971. The plant currently operates in 24 month cycles. The reactor water recirculation system (RWRS) is composed of two independent loops. Each of them has a one stage vertical centrifugal recirculation pump, with a nominal flow of 2020 l/s, and ten jet pumps. It is worthy of mention that in 1986 it was started to inject hydrogen into the feedwater (concentration = 0,3 mg/l) in order to implement the chemical condition known as hydrogen water chemistry (HWC) in the primary circuit. The objective was to create an electrochemical potential below -230 mV in the RWRS which is assumed to be low enough to mitigate the intergranular stress corrosion cracking phenomena (IGSCC) in the sensitized austenitic stainless steels. Later, in 1994, the hydrogen concentration in the feedwater was increased to 0,9 mg/l in order to obtain the protection's ECP in the bottom of the reactor vessel. This feedwater hydrogen concentration has been maintained since then. The nature of the oxides that are formed in the RWRS is strongly affected by the electrochemical conditions (ECP) which have been maintained in this system. It is frequent to find oxides like Fe 2 O 3 (hematite), Fe 3 O 4 (magnetite), NiFe 2 O 4 (trevorite), Cr 2 FeO 4 (chromite), Fe 3-x-y Cr x Ni y O 4 (spinels), etc. However, it is normal to find a combination of all of them in various proportions, depending on the ECP established. Radioactive isotopes of the transition metals ( 60 Co, 54 Mn, 51 Cr, 59 Fe, etc.) also participate in these oxides and contribute greatly to increase the dose rate in the circuit. The chemical decontamination processes are designed for the effective dissolution of the metallic oxides present and therefore the type of process to be applied will depend largely on the ECP that has been maintained in the circuit to be decontaminated. For

  8. Vortex dynamics in a pipe T-junction: Recirculation and sensitivity

    Science.gov (United States)

    Chen, Kevin K.; Rowley, Clarence W.; Stone, Howard A.

    2015-03-01

    In the last few years, many researchers have noted that regions of recirculating flow often exhibit particularly high sensitivity to spatially localized feedback. We explore the flow through a T-shaped pipe bifurcation—a simple and ubiquitous, but generally poorly understood flow configuration—and provide a complex example of the relation between recirculation and sensitivity. When Re ≥ 320, a phenomenon resembling vortex breakdown occurs in four locations in the junction, with internal stagnation points appearing on vortex axes and causing flow reversal. The structure of the recirculation is similar to the traditional bubble-type breakdown. These recirculation regions are highly sensitive to spatially localized feedback in the linearized Navier-Stokes operator. The flow separation at the corners of the "T," however, does not exhibit this kind of sensitivity. We focus our analysis on the Reynolds number of 560, near the first Hopf bifurcation of the flow.

  9. Improving sustainability of striped catfish (Pangasianodon hypophthalmus) farming in the Mekong Delta, Vietnam through recirculation technology

    NARCIS (Netherlands)

    Nguyen, Nhut

    2016-01-01

    The aim of this thesis was to document improvements in sustainability indicators of striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) production through the application of recirculation and waste treatment techniques. To be able to document improvements in sustainability, in each system

  10. The influence of preliminary aerobic treatment on the efficacy of waste stabilisation under leachate recirculation conditions

    Directory of Open Access Journals (Sweden)

    Monika Suchowska-Kisielewicz

    2014-12-01

    Full Text Available This article presents the changes in the chemical composition of leachate and the concentrations and quantity of methane production in each individual decomposition phases, determined for untreated and after aerobic treatment of waste stabilised in anaerobic reactors with and without leachate recirculation. The research results demonstrate that leachate recirculation intensifies the decomposition of both aerobically treated and untreated waste. The methane production in the reactor with untreated, stabilised waste with recirculation was 28% higher; and in the reactor with aerobically treated waste, the methane production was 24% higher than in the reactors without recirculation. An important finding of the study is that aerobic treatment of waste prior to landfilling effectively reduces the quantity of pollutant emissions in leachate and biogas from waste and increases the availability for methane micro-organisms of organic substrates from difficult-to-decompose organic substances.

  11. Prediction of required ozone dosage for pilot recirculating aquaculture systems based on laboratory studies

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Rojas-Tirado, Paula Andrea; Kaarsholm, Kamilla Marie Speht

    2017-01-01

    In recirculating aquaculture systems (RAS), the water quality changes continuously. Organic and inorganic compounds accumulates creating toxic conditions for the farmed organisms. Ozone improves water quality diminishing significantly both bacteria load and dissolved organic matter. However...

  12. Characterising organic matter in recirculating aquaculture systems with fluorescence EEM spectroscopy

    DEFF Research Database (Denmark)

    Hambly, Adam; Arvin, Erik; Pedersen, Lars-Flemming

    2015-01-01

    The potential of recirculating aquaculture systems (RAS) in the aquaculture industry is increasingly being acknowledged. Along with intensified application, the need to better characterise and understand the accumulated dissolved organic matter (DOM) within these systems increases. Mature RASs...

  13. Recirculating aquaculture production systems : an overview of different components, management, economics and technology

    NARCIS (Netherlands)

    Kals, J.

    2004-01-01

    Report of a literature study on Recirculating aquaculture production systems executed within the MRG ercirculation program. The report gives an overview of different components, management, economics and technology and is made by the Netherlands Institute for Fisheries Research (RIVO).

  14. Mechanical design of recirculating accelerator experiments for heavy-ion fusion

    International Nuclear Information System (INIS)

    Karpenko, V.

    1995-01-01

    Recirculating induction accelerators have been studied as a potential low cost driver for inertial fusion energy. At LLNL, we are developing a small (4.5-m diameter), scaled, experimental machine which will demonstrate many of the engineering solutions of a full scale driver. The small recirculator will accelerate singly ionized potassium ions from 80 to 320 keV and 2 to 8 mA, using electric dipoles for bending and permanent magnet quadrupoles for focusing in a compact periodic lattice. While very compact, and low cost, this design allows the investigation of most of the critical physics issues associated with space-charge-dominated beams in future IFE power plant drivers. This report describes the recirculator, its mechanical design, its vacuum design, and the process for aligning it. Additionally, a straight magnetic transport experiment is being carried out to test diagnostics and magnetic transport in preparation for the recirculator

  15. The impact of building recirculation rates on secondary organic aerosols generated by indoor chemistry

    DEFF Research Database (Denmark)

    Zuraimi, M.S.; Weschler, Charles J.; Tham, K.W.

    2007-01-01

    reactions between indoor limonene and ozone. The experiments were conducted in a large environmental chamber using four recirculation rates (11, 14, 19 and 24 air change per hour (ACH)) and a constant outdoor air exchange rate (I ACH) as well as constant emission rates for limonene and ozone....... As the recirculation rates increased, the deposition velocities of ozone and SOA increased. As a consequence of reduced production rates (due to less ozone) and larger surface removal rates, number and mass concentrations of SOA in different size ranges decreased significantly at higher recirculation rates. Enhanced...... coagulation at higher recirculation rates also reduced particle number concentrations, while shifting size-distributions towards larger particles. The results have health implications beyond changes in exposures, since particle size is a factor that determines where a particle deposits in the respiratory...

  16. Aircraft Recirculation Filter for Air-Quality and Incident Assessment.

    Science.gov (United States)

    Eckels, Steven J; Jones, Byron; Mann, Garrett; Mohan, Krishnan R; Weisel, Clifford P

    The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were analyzed with gas chromatograph-mass spectrometry. These samples provided a concrete link between tricresyl phosphates and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same gas chromatograph-mass spectrometry system; of that total, 107 were standard filters, and 77 were nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of tricresyl phosphates. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters.

  17. Removal of acidic pharmaceuticals within a nitrifying recirculating biofilter.

    Science.gov (United States)

    Krkošek, W H; Payne, S J; Gagnon, G A

    2014-05-30

    The fate of pharmaceutically active compounds (PhACs) in wastewater treatment systems is an area of increasing concern. Little research has been done to understand this issue in rural or decentralized communities. The objective of this research was to examine the ability of a bench scale nitrifying recirculating biofilter (RBF) to remove four acidic PhACs: gemfibrozil, naproxen, ibuprofen and diclofenac from secondary treated municipal wastewater at concentrations of 20 and 200μg/L. The average removals in this study were between 92 and 99% for ibuprofen, 89 and 99% for naproxen, 62 and 92% for gemfibrozil and 40 and 76% for diclofenac, which is consistent with literature. Ibuprofen and naproxen were largely removed through biological transformation; whereas gemfibrozil and diclofenac showed more variable removal, likely due to both biological transformation and sorption processes. PhAC removal in the RBFs was repeatable between trials, robust and responsive to system upsets, and the presence of PhACs as a single compound versus mixtures had no impact on PhAC removal efficiency. In summary, this study indicates that RBFs as a nitrifying stage of a multi-stage filtration process could be a viable technology for removal of some acidic pharmaceuticals in small onsite wastewater treatment facilities. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Muon catalyzed fusion - fission reactor driven by a recirculating beam

    International Nuclear Information System (INIS)

    Eliezer, S.; Tajima, T.; Rosenbluth, M.N.

    1986-01-01

    The recent experimentally inferred value of multiplicity of fusion of deuterium and tritium catalyzed by muons has rekindled interest in its application to reactors. Since the main energy expended is in pion (and consequent muon) productions, we try to minimize the pion loss by magnetically confining pions where they are created. Although it appears at this moment not possible to achieve energy gain by pure fusion, it is possible to gain energy by combining catalyzed fusion with fission blankets. We present two new ideas that improve the muon fusion reactor concept. The first idea is to combine the target, the converter of pions into muons, and the synthesizer into one (the synergetic concept). This is accomplished by injecting a tritium or deuterium beam of 1 GeV/nucleon into DT fuel contained in a magnetic mirror. The confined pions slow down and decay into muons, which are confined in the fuel causing little muon loss. The necessary quantity of tritium to keep the reactor viable has been derived. The second idea is that the beam passing through the target is collected for reuse and recirculated, while the strongly interacted portion of the beam is directed to electronuclear blankets. The present concepts are based on known technologies and on known physical processes and data. 29 refs., 6 figs., 4 tabs

  19. In situ treatment of VOCs by recirculation technologies

    International Nuclear Information System (INIS)

    Siegrist, R.L.; Webb, O.F.; Ally, M.R.; Sanford, W.E.; Kearl, P.M.; Zutman, J.L.

    1993-06-01

    The project described herein was conducted by Oak Ridge National Laboratory (ORNL) to identify processes and technologies developed in Germany that appeared to have near-term potential for enhancing the cleanup of volatile organic compound (VOC) contaminated soil and groundwater at DOE sites. Members of the ORNL research team identified and evaluated selected German technologies developed at or in association with the University of Karlsruhe (UoK) for in situ treatment of VOC contaminated soils and groundwater. Project activities included contacts with researchers within three departments of the UoK (i.e., Applied Geology, Hydromechanics, and Soil and Foundation Engineering) during fall 1991 and subsequent visits to UoK and private industry collaborators during February 1992. Subsequent analyses consisted of engineering computations, groundwater flow modeling, and treatment process modeling. As a result of these project efforts, two processes were identified as having near-term potential for DOE: (1) the vacuum vaporizer well/groundwater recirculation well and (2) the porous pipe/horizontal well. This document was prepared to summarize the methods and results of the assessment activities completed during the initial year of the project. The project is still ongoing, so not all facets of the effort are completely described in this document. Recommendations for laboratory and field experiments are provided

  20. Methanogenic capacity and robustness of hydrogenotrophic cultures based on closed nutrient recycling via microbial catabolism: Impact of temperature and microbial attachment.

    Science.gov (United States)

    Savvas, Savvas; Donnelly, Joanne; Patterson, Tim; Chong, Zyh Siong; Esteves, Sandra R

    2018-06-01

    A biological methanation system based on nutrient recycling via mixed culture microbial catabolism was investigated at mesophilic (37 °C) and thermophilic (55 °C) temperatures. At mesophilic temperatures, the formation of biofilms on two different types of material was assessed. Results showed that with intense mixing the biofilm reactors presented methanogenic capacities (per working volume) 50% higher than the ones operated with suspended cultures. Gas feeding rates of 200 L/L/d were achieved at a H 2 /CO 2 to CH 4 conversion efficiency of above 90% by linking two reactors in series. Furthermore the robustness of the cultures was assessed under a series of inhibitory conditions that simulated possible process interferences at full scale operation. Full recovery after separate intense oxygenation and long starvation periods was observed within 2-5 days. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. KE basin recirculation/skimmer/IX systems restart acceptance test report

    International Nuclear Information System (INIS)

    Derosa, D.C.

    1996-01-01

    The 105 KE Basin Recirculation System and Skimmer Loop have been upgraded to provide the flexibility to run the Ion Exchange Modules on either system to support spent fuel removal for the Spent Nuclear Fuel Project. This Acceptance Test Report Provides the documentation of the leak Testing for the construction work associated with the IXM inlet and outlet piping, places the cartridge filters back in service and provides the functional testing of the IXM's on the recirculation and skimmer systems

  2. Performance Study of Ceramic Filter Module in Recirculated Aquaculture System (RAS)

    Science.gov (United States)

    Ng, L. Y.; Ng, C. Y.

    2017-06-01

    The growth of world population has led to significant increase in seafood demand over the world. Aquaculture has been widely accepted by many countries to increase the seafood production owing to the decline of natural seafood resources. The aquaculture productivity, however, is directly linked to the pond water quality. In this study, attempts were made to employ ceramic micro-filter to improve the pond water quality through filtration processes. There were two batches of filtration processes, short term (1 hour) and long term (48 hours). Significant improvements on real pond water quality were recorded through the short term microfiltration process, which reduced turbidity (96%), total suspended solids (TSS) (80%), biochemical oxygen demand (BOD) (72%), chemical oxygen demand (COD) (55%), ammonia (60%), nitrate (96%) and phosphorus (83%). The long term filtration process also showed high efficiency in the removal of solid particle and organic matters. The results showed that all of the parameters were successfully reduced to acceptable ranges (turbidity<80 NTU, TSS<400 mg/L, BOD<5 mg/L, COD<70 mg/L, phosphate<3 mg/L and ammonia<0.05 mg/L) for fish culturing activity. Based on current study, there was a drastic increase in nitrate content after 24 hours due to the nitrification process by regenerated bacteria in the filtered pond water. Current study showed that the microfiltration using ceramic micro-filter has high potential to be used in recirculating aquaculture system throughout the aquaculture activities in order to maintain the pond water quality, thus, increase the survival rate of cultured species.

  3. Performance of different biofilters in a recirculating system for rainbow trout farming

    Directory of Open Access Journals (Sweden)

    Iván Sánchez O

    2016-05-01

    Full Text Available Objective. To evaluate the performance of different biofilters in a recirculating aquaculture system (RAS for trout farming. Materials and methods. It was used a 1m3 plastic tank for fries farming; fabric bags to solids retention; a submersible pump; a constant water level and flow distribution box; six up flow biofilters in 3” PVC tube; sand of D10=0.45mm as carrier. The reactors were operated at local temperature and with hydraulic retention time (HRT of 11 min, the biofilters were inoculated in the next way: R1-Control: RAS water; R2-Fish culture farm sludges; R3- Water from aerated lagoon of Antanas landfill (AL; R4-Aquarium sediments; R5- Aerated lagoon of AL sludges; R6-Sludges from sulfidogenic reactor of AL. The weight gain (WG and the food conversion (FC were evaluated, some physic-chemical parameters were monitored and the nitrogen and suspended solids removal efficiency were evaluated. Results. The WG of the cultured animals was 1.58 g/d and the FC was 1.41. There were no differences for ammonium and nitrite removal between the reactors; the average removal efficiencies were: ammonium 4.78%, nitrite 27.2%, nitrate 32.3%, suspended solids 37.5%; R4 and R5 reactors presented the best performance on nitrate removal, with average efficiencies of 47.4% and 42.8%. R3 presented the best SS removal with an average of 58.2%. Conclusions. The RAS water treatment system guaranteed appropriated liquid quality conditions for trout farming; the most efficient reactor for removal of the different forms of nitrogen was the inoculated with the aerated lagoon of AL sludges.

  4. Theoretical analysis of recirculation zone and buffer zone in the ADS windowless spallation target

    International Nuclear Information System (INIS)

    Liu, Jie; Pan, Chang-zhao; Tong, Jian-fei; Lu, Wen-qiang

    2015-01-01

    Highlights: • Height of recirculation zone is very important in windowless target design. • A theoretical formula for the height is derived based on the Bernoulli equation. • Numerical simulation for the LBE is performed and the height of recirculation zone is also obtained. • The theoretically-derived simulation-predicted recirculation zone heights agree with each other very well and the theoretical derivation is proved to be correct. - Abstract: The thermo-hydraulic analysis including reduction of the height of recirculation zone and stability of the free surface is very important in the design and optimization of ADS windowless spallation targets. In the present study, the Bernoulli equation is used to analyze the entire flow process in the target. Formulae for the height of the recirculation zone and the buffer zone are both obtained explicitly. Furthermore, numerical simulation for the heavy metal lead–bismuth eutectic liquid and vapor with cavitation phase change is also performed, and a novel method to calculate the height of the recirculation zone is put forward. By comparison of the theoretical formulae and numerical results, it is clearly shown that they agree with each other very well, and the heights predicted by the two methods are both determined by their own upstream flow parameters

  5. Effluent recirculation to improve perchlorate reduction in a fixed biofilm reactor.

    Science.gov (United States)

    Choi, Hyeoksun; Silverstein, Joann

    2007-09-01

    The effect of effluent recirculation on perchlorate reduction in a nominally plug-flow fixed biofilm reactor was studied in two cases: influent concentrations of 10 and 400 microg/L at low hydraulic loading rates (1.9 and 37.5 m(3)/m(2)/day without and with recirculation, respectively) and after a step increase in perchlorate concentration to 1,000 microg/L at the higher hydraulic loading rate (5 and 100 m(3)/m(2)/day without and with recirculation, respectively). Complete perchlorate reduction was sustained for influent concentrations of 400 and 10 microg/L in both flow regimes at the lower hydraulic loading rates. Reactor tracer profiles showed that biofilm diffusion had a more significant effect on mass transfer in the plug flow reactor compared with recirculation. The recirculation bioreactor acclimated more rapidly to increased hydraulic and perchlorate mass loading rates with significantly lower effluent perchlorate compared to the plug flow reactor: 16 microg/L versus 46 microg/L, respectively, although complete perchlorate removal was not achieved in either flow regime after 21 days acclimation to the higher loading. Total biofilm mass was more uniformly distributed in the recirculation reactor which may have contributed to better performance under increased perchlorate loading.

  6. Atmospheric stagnation, recirculation and ventilation potential of several sites in Argentina

    Science.gov (United States)

    Venegas, L. E.; Mazzeo, N. A.

    Conditions for stagnation, recirculation and ventilation potential of the atmosphere were studied in five argentine cities: Resistencia, Córdoba, Buenos Aires, Mar del Plata and Comodoro Rivadavia, located in different regions of the country. Wind run and recirculation factors were calculated for a 24-h transport time using 2 years of hourly surface measurements of wind speed and direction. The largest stagnation frequency (45% of the time) was observed in Resistencia, located in the northeastern part of the country, in an area where winds are weak. The least frequency of stagnations (2%) was observed in Comodoro Rivadavia, in the southern region of the country, a region dominated by strong westerly winds. Comodoro Rivadavia and Córdoba registered the largest frequency of recirculations. Comodoro Rivadavia exposed to sea-land breezes and Córdoba, located on a complex terrain area and exposed to local circulations, experienced recirculation events during 10% of the time. Good atmospheric ventilation occurs when a high value of wind run and a low value of the recirculation factor are observed and it can be associated with the atmosphere's capacity to replace polluted air with clean air. Ventilation events occurred 58% of the time at Comodoro Rivadavia, 52% at Mar del Plata, 40% at Buenos Aires, 35% at Córdoba and 18% at Resistencia. In general, stagnation was more frequently observed during autumn and winter, recirculation during spring and summer and good ventilation conditions occurred during spring.

  7. Targeted next-generation sequencing of the 16S-23S rRNA region for culture-independent bacterial identification - increased discrimination of closely related species

    NARCIS (Netherlands)

    Sabat, Artur J.; van Zanten, Evert; Akkerboom, Viktoria; Wisselink, Guido J; van Slochteren, Kees; de Boer, Richard F; Hendrix, Ron; Friedrich, Alexander W.; Rossen, John W. A.; Kooistra-Smid, Anna M.D. (Mirjam)

    2017-01-01

    The aim of this study was to develop an easy-to-use culture-free diagnostic method based on next generation sequencing (NGS) of PCR amplification products encompassing whole 16S-23S rRNA region to improve the resolution of bacterial species identification. To determine the resolution of the new

  8. Peracetic acid is a suitable disinfectant for recirculating fish-microalgae integrated multi-trophic aquaculture systems

    Directory of Open Access Journals (Sweden)

    Dibo Liu

    2016-11-01

    Full Text Available Integrated multi-trophic aquaculture (IMTA is a promising direction for the sustainable development of aquaculture. Microalgae have good potential to be integrated with recirculating aquaculture systems because they can use the nitrogen excreted from fish and share the same optimal pH value as in aquaculture. As a byproduct, the microalgae biomass can be used for fish feed or biofuel. However, the recirculating fish-microalgae IMTA system is under constant threat from fish pathogens and phytoplankton-lytic bacteria. Therefore, it is necessary to apply proper disinfectants as prophylaxis or treatment which are effective against these threats, but safe to fish and microalgae. For this purpose, peracetic acid (PAA is a valid option because it is highly effective against fish pathogens and bacteria at low concentrations and degrades spontaneously to harmless residues. In the present study, we exposed the culture of a marine microalgae Tetraselmis chuii once per day for four days to four PAA products with differing hydrogen peroxide (H2O2/PAA proportions at two concentrations (1 and 2 mg L−1 PAA. The H2O2 solutions at equivalent total peroxide (H2O2 + PAA concentrations were tested in parallel. The results show that the growth and photosynthesis of T. chuii were not affected by three of the PAA products (Wofasteril® E400, Wofasteril® E250 and Applichem® 150 and equivalent H2O2 solutions at both concentrations. In contrast, Wofasteril® Lspez and an equivalent H2O2 solution at both concentrations caused irreversible culture collapse, photosynthesis dysfunction and irreversible cell damage. In conclusion, PAA products with low proportions of H2O2 are optimal disinfectants for fish-microalgae IMTA systems.

  9. IC ENGINE SUPERCHARGING AND EXHAUST GAS RECIRCULATION USING JET COMPRESSOR

    Directory of Open Access Journals (Sweden)

    Adhimoulame Kalaisselvane

    2010-01-01

    Full Text Available Supercharging is a process which is used to improve the performance of an engine by increasing the specific power output whereas exhaust gas recirculation reduces the NOx produced by engine because of supercharging. In a conventional engine, supercharger functions as a compressor for the forced induction of the charge taking mechanical power from the engine crankshaft. In this study, supercharging is achieved using a jet compressor. In the jet compressor, the exhaust gas is used as the motive stream and the atmospheric air as the propelled stream. When high pressure motive stream from the engine exhaust is expanded in the nozzle, a low pressure is created at the nozzle exit. Due to this low pressure, atmospheric air is sucked into the expansion chamber of the compressor, where it is mixed and pressurized with the motive stream. The pressure of the mixed stream is further increased in the diverging section of the jet compressor. A percentage volume of the pressurized air mixture is then inducted back into the engine as supercharged air and the balance is let out as exhaust. This process not only saves the mechanical power required for supercharging but also dilutes the constituents of the engine exhaust gas thereby reducing the emission and the noise level generated from the engine exhaust. The geometrical design parameters of the jet compressor were obtained by solving the governing equations using the method of constant rate of momentum change. Using the theoretical design parameters of the jet compressor, a computational fluid dinamics analysis using FLUENT software was made to evaluate the performance of the jet compressor for the application of supercharging an IC engine. This evaluation turned out to be an efficient diagnostic tool for determining performance optimization and design of the jet compressor. A jet compressor was also fabricated for the application of supercharging and its performance was studied.

  10. Debris impact on emergency coolant recirculation - summary and conclusions

    International Nuclear Information System (INIS)

    Jain, Bhagwat; Hsia, Anthony; Armand, Yves; Mattei, Jean-Marie; Hyvaerinen, Juhani; Maqua, Michael; Puetter, Bernhard; Sandervaag, Oddbjoern; Vandewalle, Andre; Tombuyses, Beatrice; Pyy, Pekka; Royen, Jacques

    2004-01-01

    On 28 July 1992, a steam line safety relief valve inadvertently opened in the Barsebaeck-2 nuclear power plant in Sweden. The steam jet stripped fibrous insulation from adjacent piping system. Part of that insulation debris was transported to the wet-well pool and clogged the intake strainers for the drywell spray system after about one hour. Although the incident in itself was not very serious, it revealed a weakness in the defense-in-depth concept which under other circumstances could have led to the emergency core cooling system (ECCS) failing to provide recirculation water to the core. The Barsebaeck incident spurred immediate action on the part of regulators and utilities alike in several OECD countries. Research and development efforts of varying degrees of intensity were launched in many countries and in several cases resulted in findings that earlier strainer clogging data were incorrect because essential parameters and physical phenomena had not been recognized previously. Such efforts resulted in substantial back-fittings being carried out for BWRs and some PWRs in several OECD countries. An international workshop organised in Stockholm in 1994 under the auspices of CSNI revealed a rather confusing picture of the available knowledge base, examples of conflicting information and a wide range of interpretation of guidance for assessing BWR strainers and PWR sump screen performance contained in US NRC Regulatory Guide 1.82. An International Working Group was set up by the CSNI to establish an internationally agreed-upon knowledge base for assessing the reliability of ECC water recirculation systems. An initiative was taken by the CSNI in 1998 to revisit the subject. The general objective was to make an update of the knowledge base for strainer clogging, to review the latest phenomena for PWRs and to provide a survey of actions taken in member countries. New information contained in NUREG/CR-6771 indicated that the core damage frequency could increase by one

  11. Metabolites, their decomposition, production of tomato and bioassays from open and closed rockwool systems

    NARCIS (Netherlands)

    Kreij, de C.; Runia, W.T.; Burg, van der A.M.M.

    2004-01-01

    Growth, decrease in yield and other, undefined problems are reported to be due to the recirculation of the nutrient solution, which is compulsory for crops grown on substrates in the Netherlands. In a trial with tomato grown on rockwool, open and closed systems were compared. Drain water from both

  12. Closed-loop spray drying solutions for energy efficient powder production

    NARCIS (Netherlands)

    Moejes, S.N.; Visser, Q.; Bitter, J.H.; Boxtel, van A.J.B.

    2018-01-01

    This paper introduces a closed-loop dryer system to reduce the energy consumption for milk powder production. The system is based on a monodisperse droplet atomizer which reduces the amount of fines in the exhaust air, and allows dehumidification and recirculation of the air over the dryer. In this

  13. Selective exhaust gas recirculation in combined cycle gas turbine power plants with post-combustion carbon capture

    OpenAIRE

    Herraiz Palomino, Laura

    2017-01-01

    Selective Exhaust Gas Recirculation (S-EGR) consists of selectively transferring CO2 from the exhaust gas stream of a gas-fired power plant into the air stream entering the gas turbine compressor. Unlike in “non-selective” Exhaust Gas Recirculation (EGR) technology, recirculation of, principally, nitrogen does not occur, and the gas turbine still operates with a large excess of air. Two configurations are proposed: one with the CO2 transfer system operating in parallel to th...

  14. Two-well recirculation tracer tests at the H-2 hydropad, Waste Isolation Pilot Plant (WIPP), southeastern New Mexico

    International Nuclear Information System (INIS)

    1986-10-01

    Two recirculation tracer tests were performed on the Culebra Dolomite Member of the Rustler Formation at the H-2 hydropad at the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico. The first test, which used pentafluorobenzoate (PFB), sodium benzoate, and a suite of halocarbons for tracers, was terminated before breakthrough at the pumping well because of equipment failure. The second test, which used sodium thiocyanate (SCN) and difluorochlorobromomethane (BCF) as tracers, proceeded normally and lasted 270 days. During the second test, the tracer injected during the first test was recovered. Tracer test analyses for the two tests were performed only for the PFB tracer injected during the first test and recovered during the second, and for SCN. Analysis of the PFB recovery was crudely modeled as a one-dimensional pulse-injection test. The SCN tracer used in the second test was analyzed with the homogeneous, isotropic Grove and Beetem one-dimensional porous-medium recirculating flow test model. In general, model predictions are in poor agreement with the field measurements. Discrepancies could be produced by the combined effects of local nonhomogeneities, matrix diffusion, and possible sorption or degradation of the tracer during the test. The best overall match between the SCN breakthrough curve predicted by the semianalytical model and that observed in measurements was achieved using a porosity that ranged from 17% to 19% and a dispersivity of 16 to 18 ft. A match based only on the early part of the breakthrough curve, however, yielded a porosity of 11.5% and a dispersivity of 8 ft. The latter porosity might more closely represent the effective porosity of the Culebra, if the SCN degraded during the test

  15. Thermal Recirculation Modeling for Power Plants in an Estuarine Environment

    Directory of Open Access Journals (Sweden)

    Mehrdad Salehi

    2017-01-01

    Full Text Available Many power plants require large quantities of water for cooling purposes. The water taken from the source water body (e.g., lakes, estuaries, bays and rivers circulates through the plant and returns to the source through outfall with a higher temperature. For optimal performance of the power plant, the intake inlet and discharge outlet should be meticulously placed so that the heated water will not recirculate back into the power plant. In this study, the Flow module of the Delft3D software is employed to simulate the temperature transport within the study area in three-dimensional and nested format. Model results are used to optimize the location of intake inlets, outfall outlets and diffuser port orientations. The physical processes used in the study are tidal fluctuations, winds, river discharges, salinity and temperature. The subject power plant (power plant parameters presented in this paper are realistic; however, they do not target any specific power plant within the study area has a nominal capacity of 2600 MW and is planned to be located in Delaware Bay, USA. Existing field measurements are used to calibrate the model in a coupled two-staged fashion for main tidal constituents, currents and water temperature. The sensitivity of the model against various input parameters is tested, and conservative values are selected. The location of the intake is fixed, and the location of the outfall is changed until the thermal impact to the intake is less than 1 °C. Analysis of the results shows that there is a linear logarithmic relation between the excess temperatures at the intake inlet and horizontal eddy diffusivity. The k - ϵ turbulence closure results in higher excess temperature and a more conservative design. Extending the outfall location to the deeper portion of the estuary combined with port orientations reduces the impact by keeping the thermal plume away from the intake inlet and meeting the established criteria. It is concluded that

  16. Effect of stocking density on performances of juvenile turbot ( Scophthalmus maximus) in recirculating aquaculture systems

    Science.gov (United States)

    Li, Xian; Liu, Ying; Blancheton, Jean-Paul

    2013-05-01

    Limited information has been available about the influence of loading density on the performances of Scophthalmus maximus, especially in recirculating aquaculture systems (RAS). In this study, turbot (13.84±2.74 g; average weight±SD) were reared at four different initial densities (low 0.66, medium 1.26, sub-high 2.56, high 4.00 kg/m2) for 10 weeks in RAS at 23±1°C. Final densities were 4.67, 7.25, 14.16, and 17.47 kg/m2, respectively, which translate to 82, 108, 214, and 282 percent coverage of the tank bottom. Density had both negative and independent impacts on growth. The final mean weight, specific growth rate (SGR), and voluntary feed intake significantly decreased and the coefficient of variation (CV) of final body weight increased with increase in stocking density. The medium and sub-high density groups did not differ significantly in SGR, mean weight, CV, food conversion rate (FCR), feed intake, blood parameters, and digestive enzymes. The protease activities of the digestive tract at pH 7, 8.5, 9, and 10 were significantly higher for the highest density group, but tended to be lower (not significantly) at pH 4 and 8.5 for the lowest density group. The intensity of protease activity was inversely related to feed intake at the different densities. Catalase activity was higher (but not significantly) at the highest density, perhaps because high density started to induce an oxidative effect in turbot. In conclusion, turbot can be cultured in RAS at a density of less than 17.47 kg/m2. With good water quality and no feed limitation, initial density between 1.26 and 2.56 kg/m2 (final: 7.25 and 14.16 kg/m2) would not negatively affect the turbot cultured in RAS. For culture at higher density, multi-level feeding devices are suggested to ease feeding competition.

  17. Three-dimensional modelling of leachate recirculation using vertical wells in bioreactor landfills.

    Science.gov (United States)

    Feng, Shi-Jin; Chen, Zheng-Wei; Cao, Ben-Yi

    2016-12-01

    Bioreactor landfills use leachate recirculation to enhance the biodegradation of municipal solid waste and accelerate landfill stabilisation, which can provide significant environmental and economic benefits. Vertical wells are operated as a major method for leachate recirculation systems. The objectives of this article are to analyse the leachate migration in bioreactor landfills using vertical wells and to offer theoretical basis for the design of leachate recirculation systems. A three-dimensional numerical model was built using FLAC-3D, and this model can consider the saturated and unsaturated flow of leachate within anisotropic waste to reflect the actual conditions. First, main influence factors of leachate migration were analysed, including the vertical well height, hydraulic conductivity, and anisotropic coefficient, in a single-well recirculation system. Then, the effects of different configurations of a group-well system were studied and the optimal well spacing was obtained. Some key design parameters (e.g. the recirculation flow rate, volume of impact zone, radius of impact zone and time to reach steady state) were also evaluated. The results show that the hydraulic conductivity has a great impact on the optimal height of vertical wells and uniform configuration is the best option in terms of both volume of impact zone and time to reach steady state. © The Author(s) 2016.

  18. Enhancement of denitrification in a down-flow hanging sponge reactor by effluent recirculation.

    Science.gov (United States)

    Ikeda, N; Natori, T; Okubo, T; Sugo, A; Aoki, M; Kimura, M; Yamaguchi, T; Harada, H; Ohashi, A; Uemura, S

    2013-01-01

    A down-flow hanging sponge reactor, constructed by connecting three identical units in series, was applied to the treatment of artificial wastewater containing phenol and ammonia under high salinity conditions (10.9 g-Cl(-)/L). The theoretical hydraulic retention time (HRT) of each unit was 4 h (total HRT = 12 h). To enhance denitrification by effluent recirculation, the effluent recirculation ratio was increased in increments ranging from 0.0 to 2.0. The concentration of total ammonia nitrogen (TAN), NO2-N, and NO3-N in the final effluent as a proportion of the TAN in the influent was determined to calculate the unrecovered, or denitrification, proportion. The denitrification proportion of the reactor was equivalent to 19.1 ± 14.1% with no effluent recirculation; however, this was increased to 58.6 ± 6.2% when the effluent recirculation ratio was increased to 1.5. Further increasing the effluent recirculation ratio to 2.0 resulted in a decrease in the denitrification proportion to 50.9 ± 9.3%. Activity assays of nitrification and denitrification, as well as 16S rRNA gene sequence analysis, revealed that denitrification occurred primarily in the upper sections of the reactor, while nitrification increased in the lower sections of the reactor. Gene sequence analysis revealed that denitrification by Azoarcus-like species using phenol as an electron donor was dominant.

  19. Study on performance and emission characteristics of a single cylinder diesel engine using exhaust gas recirculation

    Directory of Open Access Journals (Sweden)

    Anantha Raman Lakshmipathi

    2017-01-01

    Full Text Available Exhaust gas re-circulation is a method used in compression ignition engines to control and reduce NOx emission. These emissions are controlled by reducing the oxygen concentration inside the cylinder and thereby reducing the flame temperature of the charge mixture inside the combustion chamber. In the present investigation, experiments were performed to study the effect of exhaust gas re-circulation on performance and emission characteristics in a four stroke single cylinder, water cooled and constant speed diesel engine. The experiments were performed to study the performance and emissions for different exhaust gas re-circulation ratios of the engine. Performance parameters such as brake thermal efficiency, indicated thermal efficiency, specific fuel consumption, total fuel consumption and emission parameters such as oxides of nitrogen, unburned hydrocarbons, carbon monoxide, carbon dioxide and smoke opacity were measured. Reductions in NOx and CO2 were observed but other emissions like HC, CO, and smoke opacity were found to have increased with the usage of exhaust gas re-circulation. The 15% exhaust gas re-circulation was found optimum for the engine in the aspects of performance and emission.

  20. Define of internal recirculation coefficient for biological wastewater treatment in anoxic and aerobic bioreactors

    Science.gov (United States)

    Rossinskyi, Volodymyr

    2018-02-01

    The biological wastewater treatment technologies in anoxic and aerobic bioreactors with recycle of sludge mixture are used for the effective removal of organic compounds from wastewater. The change rate of sludge mixture recirculation between bioreactors leads to a change and redistribution of concentrations of organic compounds in sludge mixture in bioreactors and change hydrodynamic regimes in bioreactors. Determination of the coefficient of internal recirculation of sludge mixture between bioreactors is important for the choice of technological parameters of biological treatment (wastewater treatment duration in anoxic and aerobic bioreactors, flow capacity of recirculation pumps). Determination of the coefficient of internal recirculation of sludge mixture requires integrated consideration of hydrodynamic parameter (flow rate), kinetic parameter (rate of oxidation of organic compounds) and physical-chemical parameter of wastewater (concentration of organic compounds). The conducted numerical experiment from the proposed mathematical equations allowed to obtain analytical dependences of the coefficient of internal recirculation sludge mixture between bioreactors on the concentration of organic compounds in wastewater, the duration of wastewater treatment in bioreactors.

  1. Elevated blood viscosity and micro-recirculation linked to coronary stent malapposition.

    Science.gov (United States)

    Poon, Eric; Thondapu, Vikas; Hayat, Umair; Barlis, Peter; Yap, Chooi; Kuo, Po; Wang, Qisen; Ma, Jiawei; Zhu, Shuang; Moore, Stephen; Ooi, Andrew

    2018-02-14

    One particular complexity of coronary artery is the natural tapering of the vessel with proximal segments having larger caliber and distal tapering as the vessel get smaller. The natural tapering of a coronary artery often leads to proximal incomplete stent apposition (ISA). ISA alters coronary hemodynamics and creates pathological path to develop complications such as in-stent restenosis, and more worryingly, stent thrombosis. By employing state-of-the-art computer-aided design software, generic stent hoops were virtually deployed in an idealized tapered coronary artery with decreasing malapposition distance. Pulsatile blood flow simulations were carried out using computational fluid dynamics (CFD) on these computer-aided design models. CFD results reveal unprecedented details in both spatial and temporal development of micro-recirculation environments throughout the cardiac cycle. Arterial tapering also introduces secondary micro-recirculation. These primary and secondary micro-recirculations provoke significant fluctuations in arterial wall shear stress (WSS). There has been a direct correlation with changes in WSS and the development of atherosclerosis. Further, the presence of these micro-recirculations influence strongly on the local levels of blood viscosity in the vicinity of the malapposed stent struts. The observation of secondary micro-recirculations and changes in blood rheology is believed to complement the wall (-based) shear stress, perhaps providing additional physical explanations for tissue accumulation near ISA detected from high resolution optical coherence tomography. This work may aid in helping to optimize future stent properties and designs that will translate to innovations that directly impact clinical outcomes.

  2. Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

    Science.gov (United States)

    Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

    2013-03-01

    Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Thermodynamic Model for Updraft Gasifier with External Recirculation of Pyrolysis Gas

    Directory of Open Access Journals (Sweden)

    Fajri Vidian

    2016-01-01

    Full Text Available Most of the thermodynamic modeling of gasification for updraft gasifier uses one process of decomposition (decomposition of fuel. In the present study, a thermodynamic model which uses two processes of decomposition (decomposition of fuel and char is used. The model is implemented in modification of updraft gasifier with external recirculation of pyrolysis gas to the combustion zone and the gas flowing out from the side stream (reduction zone in the updraft gasifier. The goal of the model obtains the influences of amount of recirculation pyrolysis gas fraction to combustion zone on combustible gas and tar. The significant results of modification updraft are that the increases amount of recirculation of pyrolysis gas will increase the composition of H2 and reduce the composition of tar; then the composition of CO and CH4 is dependent on equivalence ratio. The results of the model for combustible gas composition are compared with previous study.

  4. Recirculating flow-rate control system in an atomic power plant

    International Nuclear Information System (INIS)

    Shida, Toichi; Nakamura, Hideo; Hirose, Masao; Tohei, Kazushige.

    1975-01-01

    Object: To control recirculating flow-rate when feedwater temperature is lowered to minimize possibility of a fast-neutron flux scram, thereby maintaining soundness of fuel. Structure: An atomic power plant comprising a reactor, a recirculating flow-rate control means for controlling a power of said reactor, and a feedwater system for supplying water to said reactor, said plant further including a water temperature detector for detecting temperature of water in said feedwater system, first means for presuming the water temperature in the feedwater system corresponding to the power of the atomic power plant, and second means for obtaining a deviation between the output of said first means and the output of said water temperature detector to impact said output to the recirculating flow-rate control device, whereby preventing fluctuation in the power of the reactor due to fluctuation in water temperature. (Kamimura, M.)

  5. Further development of the V-code for recirculating linear accelerator simulations

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Sylvain; Ackermann, Wolfgang; Weiland, Thomas [Institut fuer Theorie Elektromagnetischer Felder, Technische Universitaet Darmstadt (Germany); Eichhorn, Ralf; Hug, Florian; Kleinmann, Michaela; Platz, Markus [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany)

    2011-07-01

    The Superconducting Darmstaedter LINear Accelerator (S-DALINAC) installed at the institute of nuclear physics (IKP) at TU Darmstadt is designed as a recirculating linear accelerator. The beam is first accelerated up to 10 MeV in the injector beam line. Then it is deflected by 180 degrees into the main linac. The linac section with eight superconducting cavities is passed up to three times, providing a maximal energy gain of 40 MeV on each passage. Due to this recirculating layout it is complicated to find an accurate setup for the various beam line elements. Fast online beam dynamics simulations can advantageously assist the operators because they provide a more detailed insight into the actual machine status. In this contribution further developments of the moment based simulation tool V-code which enables to simulate recirculating machines are presented together with simulation results.

  6. Effect of recirculation on organic matter removal in a hybrid constructed wetland system.

    Science.gov (United States)

    Ayaz, S C; Findik, N; Akça, L; Erdoğan, N; Kinaci, C

    2011-01-01

    This research project aimed to determine the technologically feasible and applicable wastewater treatment systems which will be constructed to solve environmental problems caused by small communities in Turkey. Pilot-scale treatment of a small community's wastewater was performed over a period of more than 2 years in order to show applicability of these systems. The present study involves removal of organic matter and suspended solids in serially operated horizontal (HFCW) and vertical (VFCW) sub-surface flow constructed wetlands. The pilot-scale wetland was constructed downstream of anaerobic reactors at the campus of TUBITAK-MRC. Anaerobically pretreated wastewater was introduced into this hybrid two-stage sub-surface flow wetland system (TSCW). Wastewater was first introduced into the horizontal sub-surface flow system and then the vertical flow system before being discharged. Recirculation of the effluent was tested in the system. When the recirculation ratio was 100%, average removal efficiencies for TSCW were 91 +/- 4% for COD, 83 +/- 10% for BOD and 96 +/- 3% for suspended solids with average effluent concentrations of 9 +/- 5 mg/L COD, 6 +/- 3 mg/L BOD and 1 mg/L for suspended solids. Comparing non-recirculation and recirculation periods, the lowest effluent concentrations were obtained with a 100% recirculation ratio. The effluent concentrations met the Turkish regulations for discharge limits of COD, BOD and TSS in each case. The study showed that a hybrid constructed wetland system with recirculation is a very effective method of obtaining very low effluent organic matter and suspended solids concentrations downstream of anaerobic pretreatment of domestic wastewaters in small communities.

  7. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

    2016-07-12

    A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

  8. Water recirculation and good management: potential methods to avoid disease outbreaks with Flavobacterium psychrophilum.

    Science.gov (United States)

    Madsen, L; Dalsgaard, I

    2008-11-01

    Flavobacterium psychrophilum infections cause high mortality among rainbow trout, Oncorhynchus mykiss, fry in Danish fish farms and hatcheries. Hatcheries based entirely on bore-hole water recirculation systems have been suggested as a possibility for eliminating F. psychrophilum or at least keeping the amount of this bacterium low. The occurrence of the bacterium in a bore-hole water recirculation system was compared with a combined bore-hole water and stream water flow-through system in a hatchery where outbreaks of rainbow trout fry syndrome caused by F. psychrophilum often occurred. Broodfish, unfertilized and fertilized eggs, eyed eggs and fry, as well as water samples from the tanks/troughs with broodfish/fry, were examined. Suspect yellow bacterial colonies were either confirmed or rejected as F. psychrophilum by growth characteristics and by PCR. As both virulent and less virulent F. psychrophilum isolates are known, isolates were characterized. The isolates were ribotyped and grouped according to ribotyping patterns. Representatives of the groups were serotyped. Fry isolates were very homogeneous whereas isolates from broodfish were heterogeneous, whether the isolates originated from external surfaces of the fish (mucus from skin and gills, haemorrhages and ulcers) or internal organs. Flavobacterium psychrophilum was isolated from broodfish in both water systems; 56% of investigated broodfish from the borehole/flowthrough system and 36% from the recirculation facility harboured the bacterium. In the recirculation system, the bacterium was isolated from fish (ulcers, milt, liver, abdominal cavity) kept in the system for 11 months. Flavobacterium psychrophilum was found in milt and ovarian fluid as well as on the surface of fertilized eggs, but not inside the eggs. Fry also harboured F. psychrophilum, but in the water recirculation system the bacterium was first isolated from the fry after they had been graded. Flavobacterium psychrophilum was found

  9. Use of planted biofilters in integrated recirculating aquaculture-hydroponics systems in the Mekong Delta, Vietnam

    DEFF Research Database (Denmark)

    Trang, N.T.D.; Brix, Hans

    2014-01-01

    The feasibility of using planted biofilters for purification of recirculated aquaculture water in the Mekong Delta of Vietnam was assessed. The plant trenches were able to clean tilapia aquaculture water and to maintain good water quality in the fish tanks without renewal of the water. NH4-N was ...... rates of 725 kg N and 234 kg P ha-1 year-1. This research demonstrates that integrated recirculating aquaculture-hydroponics (aquaponics) systems provide significant water savings and nutrient recycling as compared with traditional fish ponds....

  10. The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

    DEFF Research Database (Denmark)

    Fadeyi, M.O.; Weschler, Charles J.; Tham, K.W.

    2009-01-01

    This study examined the impact of recirculation rates (7 and 14 h(-1)), ventilation rates (1 and 2 h(-1)), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling......, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35...

  11. NUTRIENTS DYNIMIC IN AN AQUAPONIC RECIRCULATING SYSTEM FOR STURGEON AND LETTUCE (LACTUCA SATIVA PRODUCTION

    Directory of Open Access Journals (Sweden)

    LORENA SFETCU

    2008-10-01

    Full Text Available Aquaponics are modern production systems, which integrate the aquaculture technology with hydroponic systems (vegetable production without soil with a goal of fructification of residual nutrients resulted from metabolic activity of fish biomass as high quality vegetable biomass sealable as ecological products. In the present study, as a first step in aquaponic recirculating systems evaluation, the authors aim to compare two types of recirculating systems: classical (hereby noted with RAS and integrated/aquaponic (RAS_A regarding water quality parameters generally, and TAN (total ammonia nitrogen production and transformation, particularly.

  12. Closing remarks

    International Nuclear Information System (INIS)

    Reig, J.

    2007-01-01

    Good afternoon. Before providing the closing remarks on behalf of the NEA, I would like to take this opportunity and make some personal reflections, if you allow me Mr. Chairman. I have had the opportunity to take part in the three workshops on public communication organised by the NEA. In the first one in Paris in 2000, representing my country, Spain, and in the two last ones in Ottawa in 2004 and Tokyo today, on behalf of the NEA. The topics for the three workshops follow a logical order, first the focus was on investing in trust in a time when public communication was becoming a big challenge for the regulators. Second, maintaining and measuring public confidence to assess how credible regulators are in front of the public; and finally here in Tokyo, transparency, which is a basic element to achieve trust and credibility. In my view, a regulatory decision has three main components, it has to be technically sound. legally correct and well communicated. The emphasis in the early years was in the technical matters, till legal issues became a key element to achieve the political acceptance from governments and local authorities. Finally the public communication aspects resulted into a major effort and challenge to achieve social acceptance. (author)

  13. Application of the Na+ recirculation theory to ion coupled water transport in low- and high resistance osmoregulatory epithelia

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Møbjerg, Nadja; Nielsen, Robert

    2007-01-01

    The theory of Na+ recirculation for isosmotic fluid absorption follows logically from Hertz's convection-diffusion equation applied to the exit of water and solutes from the lateral intercellular space. Experimental evidence is discussed indicating Na+ recirculation based upon the following...

  14. An evaluation of a micro programmable logic controller for oxygen monitoring and control in tanks of a recirculating aquaculture system

    Science.gov (United States)

    Control of dissolved gases, especially oxygen is an essential component of recirculating aquaculture systems. The use of pure oxygen in a recirculating aquaculture system creates supersaturated concentrations of dissolved oxygen and can reduce fish production costs by supporting greater fish and fee...

  15. Use of a micro programmable logic controller for oxygen monitoring and control in multiple tanks of a recirculating aquaculture system

    Science.gov (United States)

    In intensive recirculating aquaculture systems the use of supplemental oxygen, specifically pure liquid oxygen, increases the mass of fish that can be supported and eliminates oxygen as a major limiting factor to a system’s carrying capacity. The use of pure oxygen in a recirculating aquaculture sys...

  16. Human skin is protected by four functionally and phenotypically discrete populations of resident and recirculating memory T cells

    NARCIS (Netherlands)

    Watanabe, Rei; Gehad, Ahmed; Yang, Chao; Scott, Laura L.; Teague, Jessica E.; Schlapbach, Christoph; Elco, Christopher P.; Huang, Victor; Matos, Tiago R.; Kupper, Thomas S.; Clark, Rachael A.

    2015-01-01

    The skin of an adult human contains about 20 billion memory T cells. Epithelial barrier tissues are infiltrated by a combination of resident and recirculating T cells in mice, but the relative proportions and functional activities of resident versus recirculating T cells have not been evaluated in

  17. Laser scanning of a recirculation zone on the Bolund escarpment

    DEFF Research Database (Denmark)

    Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael

    2014-01-01

    . The instrument measures the line-of-sight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. We observe a sharp interface between slow and fast moving fluid after the escarpment, and the interface is moving rapidly up and down. This implies that the position...... of the maximum velocity standard deviation is elevated a few meters above the surface. Close to the ground the mean wind is reversed relative to the general flow. The results are used to test computational fluid dynamics models for flow over terrain, and has relevance for wind energy. The preliminary comparison...... shows that the models are incapable of reproducing the reversed flow close to the surface, but more works needs to be done....

  18. Performance evaluation of Large Eddy Simulation for recirculating and swirling flows

    International Nuclear Information System (INIS)

    Hwang, Cheol Hong; Lee, Chang Eon

    2006-01-01

    The objective of this study is to evaluate the efficiency and the prediction accuracy of developed Large Eddy Simulation (LES) program for complex turbulent flows, such as recirculating and swirling flows. To save the computational cost, a Beowulf cluster system consisting 16 processors was constructed. The flows in backward-facing step and dump combustor were examined as representative recirculating and swirling flows. Firstly, a Direct Numerical Simulation (DNS) for laminar backward-facing step flows was previously conducted to validate the overall performance of program. Then LES was carried out for turbulent backward-facing step flows. The results of laminar flow showed a qualitative and quantitative agreement between simulations and experiments. The simulations of the turbulent flow also showed reasonable results. Secondly, LES results for non-swirling and swirling flows in a dump combustor were compared with the results of Reynolds-Averaged Navier-Stokes (RANS) using standard κ-ε model. The results show that LES has a better performance in predicting the mean axial and azimuthal velocities, Corner Recirculation Zone (CRZ) and Center Toroidal Recirculation Zone (CTRZ) than those of RANS. Finally, it was examined the capability of LES for the description of unsteady phenomena

  19. The effect of leachate recirculation with enzyme cellulase addition on waste stability in landfill bioreactor

    Science.gov (United States)

    Saffira, N.; Kristanto, G. A.

    2018-01-01

    Landfill bioreactor with leachate recirculation is known to enhance waste stabilization. However, the composition of waste in Indonesia is comprised by organic waste which is lignocellulosic materials that considered take a long time to degrade under anaerobic condition. To accelerate the degradation process, enzyme addition is ought to do. Cellulase is an enzyme that can catalyse cellulose and other polysaccharide decomposition processes. Therefore, operation of waste degradation using leachate recirculation with a cellulase addition to enhance waste stabilization was investigated using anaerobic bioreactor landfill. The experiment was performed on 2 conditions; leachate recirculation with cellulase addition and recirculation only as a control. The addition of cellulase is reported to be significant in decreasing organic content, represented by volatile solid parameter. The volatile solid reduction in the cellulase augmented reactor and control reactor was 17.86% and 7.90%, respectively. Cellulase addition also resulted in the highest cellulose reduction. Settlement of the landfill in a bioreactor with enzyme addition (32.67%) was reported to be higher than the control (19.33%). Stabilization of landfill review by the decreasing rate constant of the cellulose and lignin ratio parameter was more rapidly achieved by the enzyme addition (0.014 day-1) compared to control (0.002 day-1).

  20. Pilot-scale study of powdered activated carbon recirculation for micropollutant removal.

    Science.gov (United States)

    Meinel, F; Sperlich, A; Jekel, M

    Adsorption onto powdered activated carbon (PAC) is a promising technique for the removal of organic micropollutants (OMPs) from treated wastewater. To enhance the adsorption efficiency, PAC is recycled back into the adsorption stage. This technique was examined in pilot scale in comparison to a reference without recirculation. Coagulation with Fe(3+) was carried out simultaneously to adsorption. Extensive OMP measurements showed that recirculation significantly increased OMP eliminations. Thus, significant PAC savings were feasible. The PAC concentration in the contact reactor proved to be an important operating parameter that can be surrogated by the easily measurable total suspended solids (TSS) concentration. OMP eliminations increased with increasing TSS concentrations. At 20 mg PAC L(-1) and 2.8 g TSS L(-1) in the contact reactor, well-adsorbable carbamazepine was eliminated by 97%, moderately adsorbable diclofenac was eliminated by 92% and poorly-adsorbable acesulfame was eliminated by 54% in comparison to 49%, 35% and 18%, respectively, without recirculation. The recirculation system represents an efficient technique, as the PAC's adsorption capacity is practically completely used. Small PAC dosages yield high OMP eliminations. Poorly-adsorbable gabapentin was eliminated to an unexpectedly high degree. A laboratory-scale biomass inhibition study showed that aerobic biodegradation removed gabapentin in addition to adsorption.

  1. The benefits of powdered activated carbon recirculation for micropollutant removal in advanced wastewater treatment.

    Science.gov (United States)

    Meinel, F; Zietzschmann, F; Ruhl, A S; Sperlich, A; Jekel, M

    2016-03-15

    PAC adsorption is a widespread option for the removal of organic micropollutants (OMP) from secondary effluent. For an optimal exploitation of the adsorption capacity, PAC recirculation is nowadays a common practice, although the mechanistic interrelations of the complex recirculation process are not fully resolved. In this work, extensive multi-stage batch adsorption testing with repeated PAC and coagulant dosage was performed to evaluate the continuous-flow recirculation system. Partly loaded PAC showed a distinct amount of remaining capacity, as OMP and DOC removals considerably increased with each additional adsorption stage. At a low PAC dose of 10 mg PAC L(-1), removals of benzotriazole and carbamazepine were shown to rise from 80% in the 11th stage at 30 min adsorption time per stage. At a high PAC dose of 30 mg PAC L(-1), OMP and DOC removals were significantly higher and reached 98% (for benzotriazole and carbamazepine) after 11 stages. Coagulant dosage showed no influence on OMP removal, whereas a major part of DOC removal can be attributed to coagulation. Multi-stage adsorption is particularly beneficial for small PAC doses and significant PAC savings are feasible. A new model approach for predicting multi-stage OMP adsorption on the basis of a single-stage adsorption experiment was developed. It proved to predict OMP removals and PAC loadings accurately and thus contributes towards understanding the PAC recirculation process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Effect of substrate-seed mixing and leachate recirculation on solid state digestion of biowaste

    NARCIS (Netherlands)

    Veeken, A.H.M.; Hamelers, H.V.M.

    2000-01-01

    Lab-scale experiments were performed and a mechanistic model was developed to simulate the solid state digestion of biowaste in a batch reactor. Both experiments and model showed that the substrate-seed mixing degree and leachate recirculation rate have a strong effect on the reactor performance.

  3. THERMODYNAMIC MODEL OF THE CYCLE OF SPARK IGNITION ENGINE WITH EXHAUST GAS RECIRCULATION

    OpenAIRE

    Öğüçlü, Özer

    2015-01-01

    A thermodynamic model has been developed and applied to predict the emission levels and performance of a spark ignition engine with using Exhaust Gas Recirculation (EGR) gas. The model simulates the full thermodynamic cycle of the engine and includes heat transfer, combustion, gas exchange process, thermal dissociation of water and carbon dioxide, and chemical equilibrium. 

  4. Exhaust Gas Recirculation Control for Large Diesel Engines - Achievable Performance with SISO Design

    DEFF Research Database (Denmark)

    Hansen, Jakob Mahler; Blanke, Mogens; Niemann, Hans Henrik

    2013-01-01

    This paper investigates control possibilities for Exhaust Gas Recirculation (EGR) on large diesel engines. The goal is to reduce the amount of NOx in the exhaust gas by reducing the oxygen concentration available for combustion. Control limitations imposed by the system are assessed using linear...

  5. Effect of recirculation and regional counting rate on reliability of noninvasive bicompartmental CBF measurements

    International Nuclear Information System (INIS)

    Herholz, K.

    1985-01-01

    Based on data from routine intravenous Xe133-rCBF studies in 50 patients, using Obrist's algorithm the effect of counting rate statistics and amount of recirculating activity on reproducibility of results was investigated at five simulated counting rate levels. Dependence of the standard deviation of compartmental and noncompartmental flow parameters on recirculation and counting rate was determined by multiple linear regression analysis. Those regression equations permit determination of the optimum accuracy that may be expected from individual flow measurements. Mainly due to a delay of the start-of-fit time an exponential increase in standard deviation of flow measurements was observed as recirculation increased. At constant start-of-fit, however, a linear increase in standard deviation of compartmental flow parameters only was found, while noncompartmental results remained constant. Therefore, and in regard to other studies of potential sources of error, an upper limit of 2.5 min for the start-of-fit time and usage of noncompartmental flow parameters for measurements affected by high recirculation are suggested

  6. Improving sustainability of striped catfish (Pangasianodon hypophthalmus) farming in the Mekong Delta, Vietnam through recirculation technology

    NARCIS (Netherlands)

    Nguyen, Nhut

    2016-01-01

    The aim of this thesis was to document improvements in sustainability indicators of striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) production through the application of recirculation and waste treatment techniques. To be able to document improvements in sustainability, in each

  7. Geophysical monitoring of recirculation of leachate on landfill sites in the Netherlands

    NARCIS (Netherlands)

    Kruiver, P.P.; Westerhoff, R.S.; Noorlandt, R.P.; Hoekstra, N.N.; Woelders, H.; Vossen, W.J. van

    2009-01-01

    Geophysical investigations were carried out on two modern landfill sites in the Netherlands. The objective of the geo-electrical and EM31 measurements was to reveal the effect of recirculation of leachate on homogenising moisture content in the waste to stimulate the process of attenuation. At

  8. Building America Case Study: Control Retrofits for Multifamily Domestic Hot Water Recirculation Systems, Brooklyn, New York

    Energy Technology Data Exchange (ETDEWEB)

    J. Dentz; E. Ansanelli, H. Henderson, Jr.; K. Varshney

    2016-12-01

    Domestic hot water (DHW) heating is the second largest energy end use in U.S. buildings, exceeded only by space conditioning. Recirculation systems consisting of a pump and piping loop(s) are commonly used in multifamily buildings to reduce wait time for hot water at faucets; however, constant pumping increases energy consumption by exposing supply and return line piping to continuous heat loss, even during periods when there is no demand for hot water. In this study, ARIES installed and tested two types of recirculation controls in a pair of buildings in order to evaluate their energy savings potential. Demand control, temperature modulation controls, and the simultaneous operation of both were compared to the baseline case of constant recirculation. Additionally, interactive effects between DHW control fuel reductions and space conditioning (heating and cooling) were estimated in order to make more realistic predictions of the payback and financial viability of retrofitting DHW systems with these controls. Results showed that DHW fuel consumption reduced by 7% after implementing the demand control technique, 2% after implementing temperature modulation, and 15% after implementing demand control and temperature modulation techniques simultaneously; recirculation pump runtime was reduced to 14 minutes or less per day. With space heating and cooling interactions included, the estimated annual cost savings were 8%, 1%, and 14% for the respective control techniques. Possible complications in the installation, commissioning and operation of the controls were identified and solutions offered.

  9. Building America Case Study: Control Retrofits for Multifamily Domestic Hot Water Recirculation Systems, Brooklyn, New York

    Energy Technology Data Exchange (ETDEWEB)

    2016-12-01

    Domestic hot water (DHW) heating is the second largest energy end use in U.S. buildings, exceeded only by space conditioning. Recirculation systems consisting of a pump and piping loop(s) are commonly used in multifamily buildings to reduce wait time for hot water at faucets; however, constant pumping increases energy consumption by exposing supply and return line piping to continuous heat loss, even during periods when there is no demand for hot water. In this study, ARIES installed and tested two types of recirculation controls in a pair of buildings in order to evaluate their energy savings potential. Demand control, temperature modulation controls, and the simultaneous operation of both were compared to the baseline case of constant recirculation. Additionally, interactive effects between DHW control fuel reductions and space conditioning (heating and cooling) were estimated in order to make more realistic predictions of the payback and financial viability of retrofitting DHW systems with these controls. Results showed that DHW fuel consumption reduced by 7 percent after implementing the demand control technique, 2 percent after implementing temperature modulation, and 15 percent after implementing demand control and temperature modulation techniques simultaneously; recirculation pump runtime was reduced to 14 minutes or less per day. With space heating and cooling interactions included, the estimated annual cost savings were 8 percent, 1 percent, and 14 percent for the respective control techniques. Possible complications in the installation, commissioning and operation of the controls were identified and solutions offered.

  10. Development of FET-switched induction accelerator cells for heavy-ion fusion recirculators

    International Nuclear Information System (INIS)

    Newton, M.A.; Cravey, W.R.; Hawkins, S.A.; Kirbie, H.C.; Ollis, C.W.

    1993-01-01

    The ''recirculator,'' a recirculating heavy-ion induction accelerator, has been identified as a promising approach for an inertial fusion driver. One of the technical challenges to building a recirculator is the requirement for a modulator that can drive the induction accelerator cells at repetition rates ≥ 100 kHz with variable pulse width and pulse repetition rate capability. A high repetition rate modulator and cell is presently being developed for use on a proposed heavy-ion recirculator. The goal is to develop an array of field-effect transistors to switch 5 kV, 1 μs pulses onto a Metglas induction core at pulse rates exceeding 100 kHz. Each transistor in the array is driven by a fiber-optic isolated gate signal that is powered by a dc/dc converter. The circuit architecture provides for core reset between pulses and produces bursts of pulses that are variable in pulse width and prf. The transistor switching array, energy storage capacitors, reset circuit and cell core are all combined into a single compact, low-impedance package. Progress of this development work will be presented with supporting data

  11. Study of atmospheric stagnation, recirculation, and ventilation potential at Narora Atomic Power Station site

    International Nuclear Information System (INIS)

    Kumar, Deepak; Kumar, Avinash; Kumar, Vimal; Rao, K.S.; Kumar, Jaivender; Ravi, P.M.

    2011-01-01

    Atmosphere is an important pathway to be considered in assessment of the environmental impact of radioactivity releases from nuclear facilities. Estimation of concentration of released effluents in air and possible ground contamination needs an understanding of relevant atmospheric dispersion. This article describes the meteorological characteristics of Narora Atomic Power Station (NAPS) site by using the integral parameters developed by Allwine and Whiteman. Meteorological data measured during the period 2006-2010 were analyzed. The integral quantities related to the occurrence of stagnation, recirculation, and ventilation characteristics were studied for NAPS site to assess the dilution potential of the atmosphere. Wind run and recirculation factors were calculated for a 24-h transport time using 5 years of hourly surface measurements of wind speed and direction. The occurrence of stagnation, recirculation, and ventilation characteristics during 2006-2010 at NAPS site is observed to be 33.8% of the time, 19.5% of the time, and 34.7% of the time, respectively. The presence of strong winds with predominant wind direction NW and WNW during winter and summer seasons leads to higher ventilation (48.1% and 44.3%) and recirculation (32.6% of the summer season). The presence of light winds and more dispersed winds during prewinter season with predominant wind directions W and WNW results in more stagnation (59.7% of the prewinter season). Thus, this study will serve as an essential meteorological tool to understand the transport mechanism of atmospheric radioactive effluent releases from any nuclear industry. (author)

  12. Steroids accumulate in the rearing water of commercial recirculating aquaculture systems

    NARCIS (Netherlands)

    Mota, V.C.; Martins, C.I.; Eding, E.H.; Canário, A.V.M.; Verreth, J.A.J.

    2014-01-01

    Little information is available on steroid concentrations in the rearing water of aquaculture systems and whether they accumulate in recirculating aquaculture systems (RAS). Therefore this study aimed at determining (1) the concentrations and variation of cortisol and sex steroids in RAS, (2) the

  13. Influence of fixed and moving bed biofilters on micro particle dynamics in a recirculating aquaculture system

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2017-01-01

    Accumulation of fine particulate organic matter in recirculating aquaculture systems (RAS) is a balancebetween system input (from feed to waste), internal transformation, removal and dilution. The mecha-nisms leading to fine particle accumulation in RAS are not fully understood, and neither...

  14. Degradation and effect of hydrogen peroxide in small-scale recirculation aquaculture system biofilters

    DEFF Research Database (Denmark)

    Møller, Martin Sune; Arvin, Erik; Pedersen, Lars-Flemming

    2010-01-01

    applied in different systems. In this study, we investigated the degradation kinetics of HP in biofilters from water recirculating aquaculture systems (RAS). The potential effect of HP on the nitrification process in the biofilters was also examined. Biofilter elements from two different pilot-scale RAS...

  15. Use of fluorescence spectroscopy to control ozone dosage in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Martin, Richard; Pedersen, Lars-Flemming

    2017-01-01

    The aim of this study was to investigate the potential of fluorescence spectroscopy to be used as an ozone dosage determination tool in recirculating aquaculture systems (RASs), by studying the relationship between fluorescence intensities and dissolved organic matter (DOM) degradation by ozone...

  16. Bacterial activity dynamics in the water phase during start-up of recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Rojas-Tirado, Paula Andrea; Pedersen, Per Bovbjerg; Pedersen, Lars-Flemming

    2017-01-01

    tMicrobial water quality in recirculating aquaculture systems (RAS) is important for successful RAS opera-tion but difficult to assess and control. There is a need to identify factors affecting changes in the bacterialdynamics – in terms of abundance and activity – to get the information needed...

  17. New developments in recirculating aquaculture systems in Europe: a perspective on environmental sustainability

    NARCIS (Netherlands)

    Martins, C.I.; Eding, E.H.; Verdegem, M.C.J.; Heinsbroek, L.T.N.; Schneider, O.; Blancheton, J.P.; Roque dÓrbcastel, E.; Verreth, J.A.J.

    2010-01-01

    The dual objective of sustainable aquaculture, i.e., to produce food while sustaining natural resources is achieved only when production systems with a minimum ecological impact are used. Recirculating aquaculture systems (RASs) provide opportunities to reduce water usage and to improve waste

  18. Reliability analysis of air recirculation and refrigeration systems of Angra-1 reactor contaiment: a reevaluation

    International Nuclear Information System (INIS)

    Oliveira, L.F.S. de; Fleming, P.V.; Frutuoso e Melo, P.F.F.

    1983-01-01

    A realiability analysis of the air refrigeration and recirculation containment systems (ARRCS) of Angra-1 nuclear power plants, were done, aiming to evaluate the probabilities of occurence of a several accident. The systems were analysed for a 24 hours accident, including time failures and demand failures [pt

  19. HRT and nutrients affect bacterial communities grown on recirculation aquaculture system effluents

    NARCIS (Netherlands)

    Schneider, O.; Chabrillon-Popelka, M.; Smidt, H.; Haenen, O.L.M.; Sereti, V.; Eding, E.H.; Verreth, J.A.J.

    2007-01-01

    In a recirculation aquaculture system the drumfilter effluent can be used as substrate for heterotrophic bacterial production, which can be recycled as feed. Because the bacteria might contain pathogens, which could reduce its suitability as feed, it is important to characterize these communities.

  20. Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste With Recirculation of Process Water

    DEFF Research Database (Denmark)

    Hartmann, H.; Angelidaki, Irini; Ahring, Birgitte Kiær

    2001-01-01

    A new concept of a wet anaerobic digestion treatment of the organic fraction of municipal solid waste (OFMSW) is investigated. Once the waste is diluted with water, the entire liquid fraction of the effluent is recirculated and used as process water for dilution of the waste. This enables a well...

  1. Removal of Nutrients from Septic Effluent with Re-circulated Hybrid Tidal Flow Constructed Wetland

    Science.gov (United States)

    Lihua Cui; Jigkun Feng; Ying Ouyang; Peiwen. Deng

    2012-01-01

    Hybrid tidal flow constructed wetland (CW) with recirculation is an improved biological and engineering technique for removal of excess nutrients and certain pollutants from wastewater. This study investigated the removal efficiency of total phosphorus (TP), ammonia-nitrogen (NH3-N), and total nitrogen (TN) from septic tank effluent with the hybrid tidal flow CW system...

  2. Development of new design mechanical seal tester for Primary Loop Recirculation Pump (PLR Pump)

    International Nuclear Information System (INIS)

    Fukushima, Naoki; Koshiba, Koremutsu

    1995-01-01

    The mechanical seal for a Primary Loop Recirculation Pump (PLR Pump) is an important part of a BWR plant. This study describes a new mechanical seal tester developed to certify mechanical seal performance before installation in a PLR Pump on site. (author)

  3. Water cortisol and testosterone in Nile tilapia (Oreochromis niloticus) recirculating aquaculture systems

    NARCIS (Netherlands)

    Mota, Vasco C.; Martins, Catarina I.M.; Eding, Ep H.; Canário, Adelino V.M.; Verreth, Johan A.J.

    2017-01-01

    The accumulation of steroids released by fish in recirculating aquaculture systems (RAS) may potentially influence their physiology and behavior. The present study examined the release rate of cortisol and testosterone by Nile tilapia, Oreochromis niloticus, and their accumulation in six identical

  4. Fulminant hepatic failure following marijuana drug abuse: Molecular adsorbent recirculation system therapy

    Directory of Open Access Journals (Sweden)

    G Swarnalatha

    2013-01-01

    Full Text Available Marijuana is used for psychoactive and recreational purpose. We report a case of fulminant hepatic failure following marijuana drug abuse who recovered following artificial support systems for acute liver failure. There is no published literature of management of marijuana intoxication with molecular adsorbent recirculation system (MARS. MARS is effective and safe in patients with fulminant hepatic failure following marijuana intoxication.

  5. Improvement of anaerobic digester performance by wastewater recirculation through an aerated membrane.

    Science.gov (United States)

    Swine wastewater from an anaerobic digester was recirculated through a silicone hose located in an external aeration chamber to determine its effect on wastewater malodorants and biogas composition. The silicone hose acted as a semipermeable membrane for the passage of small molecules. In the first...

  6. Treatment of fishpond water by recirculating horizontal and vertical flow constructed wetlands in the tropics

    DEFF Research Database (Denmark)

    Konnerup, Dennis; Trang, Ngo Thuy Diem; Brix, Hans

    2011-01-01

    efficient use of water and less environmental impact. The aim of this study was to assess the suitability of using constructed wetlands (CWs) for the treatment of fishpond water in a recirculating aquaculture system in the Mekong Delta of Vietnam. Water from a fishpond stocked with Nile tilapia (Oreochromis...... and the associated environmental impact can be significantly reduced. © 2011 Elsevier B.V....

  7. Suction-recirculation device for stabilizing particle flows within a solar powered solid particle receiver

    Science.gov (United States)

    Kolb, Gregory J [Albuquerque, NM

    2012-02-07

    A suction-recirculation device for stabilizing the flow of a curtain of blackened heat absorption particles falling inside of a solar receiver with an open aperture. The curtain of particles absorbs the concentrated heat from a solar mirror array reflected up to the receiver on a solar power tower. External winds entering the receiver at an oblique angle can destabilize the particle curtain and eject particles. A fan and ductwork is located behind the back wall of the receiver and sucks air out through an array of small holes in the back wall. Any entrained particles are separated out by a conventional cyclone device. Then, the air is recirculated back to the top of the receiver by injecting the recycled air through an array of small holes in the receiver's ceiling and upper aperture front wall. Since internal air is recirculated, heat losses are minimized and high receiver efficiency is maintained. Suction-recirculation velocities in the range of 1-5 m/s are sufficient to stabilize the particle curtain against external wind speeds in excess of 10 m/s.

  8. Adoption of Recirculating Aquaculture Systems in Pangasius Farms: A Choice Experiment

    NARCIS (Netherlands)

    Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.T.; Bosma, R.H.; Oude Lansink, A.G.J.M.

    2015-01-01

    A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

  9. Adoption of Recirculating Aquaculture Systems in Large Pangasius Farms: A Choice Experiment

    NARCIS (Netherlands)

    Pham, T.A.N.; Gielen-Meuwissen, M.P.M.; Le, T.C.; Verreth, J.A.J.; Bosma, R.H.; Oude Lansink, A.G.J.M.

    2016-01-01

    A growing number of European customers’ demands certified pangasius such as ASC in order to ensure sustainable production. Implementing Recirculating Aquaculture Systems (RAS) contributes to an improved water quality, a key issue in achieving ASC certification. This study uses a choice experiment to

  10. Observations on side-swimming rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Science.gov (United States)

    During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRAS), it was observed that rainbow trout Oncorhynchus mykiss in all WRAS exhibited a higher-than-normal prevalence of side-swimming (i.e. controlled, forward swimming, but with misaligned orientation suc...

  11. Different effectiveness of closed embryo culture system with time-lapse imaging (EmbryoScope(TM)) in comparison to standard manual embryology in good and poor prognosis patients: a prospectively randomized pilot study.

    Science.gov (United States)

    Wu, Yan-Guang; Lazzaroni-Tealdi, Emanuela; Wang, Qi; Zhang, Lin; Barad, David H; Kushnir, Vitaly A; Darmon, Sarah K; Albertini, David F; Gleicher, Norbert

    2016-08-24

    Previously manual human embryology in many in vitro fertilization (IVF) centers is rapidly being replaced by closed embryo incubation systems with time-lapse imaging. Whether such systems perform comparably to manual embryology in different IVF patient populations has, however, never before been investigated. We, therefore, prospectively compared embryo quality following closed system culture with time-lapse photography (EmbryoScope™) and standard embryology. We performed a two-part prospectively randomized study in IVF (clinical trial # NCT92256309). Part A involved 31 infertile poor prognosis patients prospectively randomized to EmbryoScope™ and standard embryology. Part B involved embryos from 17 egg donor-recipient cycles resulting in large egg/embryo numbers, thus permitting prospectively alternative embryo assignments to EmbryoScope™ and standard embryology. We then compared pregnancy rates and embryo quality on day-3 after fertilization and embryologist time utilized per processed embryo. Part A revealed in poor prognosis patients no differences in day-3 embryo scores, implantation and clinical pregnancy rates between EmbryoScope™ and standard embryology. The EmbryoScope™, however, more than doubled embryology staff time (P embryology. Appropriately designed and powered prospectively randomized studies appear urgently needed in well-defined patient populations before the uncontrolled utilization of these instruments further expands. NCT02246309 Registered September 18, 2014.

  12. Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  13. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  14. Simultaneous water desalination and electricity generation in a microbial desalination cell with electrolyte recirculation for pH control.

    Science.gov (United States)

    Qu, Youpeng; Feng, Yujie; Wang, Xin; Liu, Jia; Lv, Jiangwei; He, Weihua; Logan, Bruce E

    2012-02-01

    A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m(2) with a 50mM phosphate buffer solution (PBS) and 776±30mW/m(2) with 25mM PBS. These power densities were higher than those obtained without recirculation of 698±10mW/m(2) (50mM PBS) and 508±11mW/m(2) (25mM PBS). The salt solution (20g/L NaCl) was reduced in salinity by 34±1% (50mM) and 37±2% (25mM) with recirculation (rMDC), and by 39±1% (50mM) and 25±3% (25mM) without recirculation (MDC). These results show that electrolyte recirculation using an rMDC is an effective method to increase power and achieve efficient desalination by eliminating pH imbalances. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Effect of pH-neutralized leachate recirculation on a combined hydrolytic-aerobic biopretreatment for municipal solid waste.

    Science.gov (United States)

    Zhang, Dong-Qing; He, Pin-Jing; Shao, Li-Ming

    2009-09-01

    Four trials with different durations (1, 2, 3 and 4 days) of neutralized leachate recirculation and a control with distilled water recirculation for 4 days were set up to investigate the effect of recirculation duration on MSW biopretreatment by a combined hydrolytic-aerobic process. Results showed that recirculation could enhance water removal and organics degradation rates and thus lead to a lower water content of biopretreated materials, when compared with the control. Recirculation with duration of 4 days had the highest rates of water removal (83.7%) and organics degradation (62.1%) and lowest final water content (43.1%) due to the elimination of acid inhibition. As a result, recirculation with duration of 4 days had the highest sorting efficiency (75%) and heating value (10570 kJ/kg) and lowest respiration activity (98.6 mgO(2)/g). Thereby, neutralized leachate recirculation with duration of 4 days was suggested to pretreat municipal solid waste with high water content.

  16. Automation of water supply and recirculation-filtration of water at a swimming pool using Zelio PLC

    Science.gov (United States)

    Diniş, C. M.; Popa, G. N.; Iagăr, A.

    2018-01-01

    The paper proposes the use of the Zelio PLC for the automation of the water supply and recirculation-filtration system of a swimming pool. To do this, the Zelio SR3B261BD - 24V DC with 10 digital inputs (24V DC) and 10 digital outputs (relay contacts) was used. The proposed application makes the control of the water supply pumps and the water recirculation-filtration from a swimming pool. The recirculation-filtration systems for pools and swimming pools are designed to ensure water cleaning and recirculation to achieve optimum quality and lasting service life. The water filtration process is one of the important steps in water treatment in polls and swimming pools. It consists in recirculation of the entire volume of water and begins by absorbing the water in the pool by means of a pump followed by the passing of water through the filter, disinfectant and pH dosing, and reintroducing the water back into the pool or swimming pool through the discharge holes. Filters must to work 24 hours a day to remove pollutants from pools or swimming pools users. Filtration removes suspension particles with different origins. All newly built pools and swimming pools must be fitted with water recirculation systems, and existing ones will be equipped with water recirculation and water treatment systems.

  17. Simultaneous water desalination and electricity generation in a microbial desalination cell with electrolyte recirculation for pH control

    KAUST Repository

    Qu, Youpeng

    2012-02-01

    A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m 2 with a 50mM phosphate buffer solution (PBS) and 776±30mW/m 2 with 25mM PBS. These power densities were higher than those obtained without recirculation of 698±10mW/m 2 (50mM PBS) and 508±11mW/m 2 (25mM PBS). The salt solution (20g/L NaCl) was reduced in salinity by 34±1% (50mM) and 37±2% (25mM) with recirculation (rMDC), and by 39±1% (50mM) and 25±3% (25mM) without recirculation (MDC). These results show that electrolyte recirculation using an rMDC is an effective method to increase power and achieve efficient desalination by eliminating pH imbalances. © 2011 Elsevier Ltd.

  18. Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

    Energy Technology Data Exchange (ETDEWEB)

    Loenhout, Gerard van [Flowserve B.V., Etten-Leur (Netherlands). Nuclear Services and Solutions Engineering; Hurni, Juerg

    2014-07-01

    A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. The paper describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motorgenerator set.

  19. Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

    International Nuclear Information System (INIS)

    Loenhout, Gerard van; Hurni, Juerg

    2014-01-01

    A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. The paper describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motorgenerator set.

  20. Reforming results of a novel radial reactor for a solid oxide fuel cell system with anode off-gas recirculation

    Science.gov (United States)

    Bosch, Timo; Carré, Maxime; Heinzel, Angelika; Steffen, Michael; Lapicque, François

    2017-12-01

    A novel reactor of a natural gas (NG) fueled, 1 kW net power solid oxide fuel cell (SOFC) system with anode off-gas recirculation (AOGR) is experimentally investigated. The reactor operates as pre-reformer, is of the type radial reactor with centrifugal z-flow, has the shape of a hollow cylinder with a volume of approximately 1 L and is equipped with two different precious metal wire-mesh catalyst packages as well as with an internal electric heater. Reforming investigations of the reactor are done stand-alone but as if the reactor would operate within the total SOFC system with AOGR. For the tests presented here it is assumed that the SOFC system runs on pure CH4 instead of NG. The manuscript focuses on the various phases of reactor operation during the startup process of the SOFC system. Startup process reforming experiments cover reactor operation points at which it runs on an oxygen to carbon ratio at the reactor inlet (ϕRI) of 1.2 with air supplied, up to a ϕRI of 2.4 without air supplied. As confirmed by a Monte Carlo simulation, most of the measured outlet gas concentrations are in or close to equilibrium.

  1. Synergistic Effects of Micro-electrolysis-Photocatalysis on Water Treatment and Fish Performance in Saline Recirculating Aquaculture System.

    Science.gov (United States)

    Ye, Zhangying; Wang, Shuo; Gao, Weishan; Li, Haijun; Pei, Luowei; Shen, Mingwei; Zhu, Songming

    2017-03-27

    A new physico-chemical process for TAN (total ammonia nitrogen) removal and disinfection is introduced in saline recirculating aquaculture system (RAS), in which the biofilter is replaced with an integrated electrolysis cell and an activated carbon filter. The electrolysis cell which is based on micro current electrolysis combined with UV-light was self-designed. After the fundamental research, a small pilot scale RAS was operated for 30 days to verify the technical feasibility. The system was stocked by 42 GIFT tilapia (Oreochromis niloticus) fish with the rearing density of 13 kg/m 3 . During the experiments, the TAN concentration remained below 1.0 mg/L. The nitrite concentration was lower than 0.2 mg/L and the nitrate concentration had increased continuously to 12.79 mg/L at the end. Furthermore, the concentration of residual chlorine in culture ponds remained below 0.3 mg/L, ORP maintained slight fluctuations in the range of 190~240 mV, and pH of the water showed the downtrend. Tilapia weight increased constantly to 339.3 ± 10 g. For disinfection, the active chlorine generated by electrochemical treatment caused Escherichia coli inactivation. Enzyme activity assay indicated that the activity of glutamate dehydrogenase, carbonic anhydrase and glutamic pyruvic transaminase increased within the normal range. The preliminary feasibility was verified by using this physico-chemical technology in the RAS.

  2. Comparison of aerobically-treated and untreated crop residue as a source of recycled nutrients in a recirculating hydroponic system

    Science.gov (United States)

    Mackowiak, C. L.; Garland, J. L.; Strayer, R. F.; Finger, B. W.; Wheeler, R. M.

    1996-01-01

    This study compared the growth of potato plants on nutrients recycled from inedible potato biomass. Plants were grown for 105 days in recirculating, thin-film hydroponic systems containing four separate nutrient solution treatments: (1) modified half-strength Hoagland's (control), 2) liquid effluent from a bioreactor containing inedible potato biomass, 3) filtered (0.2 micrometer) effluent, and 4) the water soluble fraction of inedible potato biomass (leachate). Approximately 50% of the total nutrient requirement in treatments 2-4 were provided (recycled) from the potato biomass. Leachate had an inhibitory effect on leaf conductance, photosynthetic rate, and growth (50% reduction in plant height and 60% reduction in tuber yield). Plants grown on bioreactor effluent (filtered or unfiltered) were similar to the control plants. These results indicated that rapidly degraded, water soluble organic material contained in the inedible biomass, i.e., material in leachate, brought about phytotoxicity in the hydroponic culture of potato. Recalcitrant, water soluble organic material accumulated in all nutrient recycling treatments (650% increase after 105 days), but no increase in rhizosphere microbial numbers was observed.

  3. Effect of copper on the growth of shrimps Litopenaeus vannamei: water parameters and copper budget in a recirculating system

    Science.gov (United States)

    Cheng, Bo; Liu, Ying; Yang, Hongsheng; Song, Yi; Li, Xian

    2014-09-01

    Shrimps ( Litopenaeus vannamei) were intensively cultured in a recirculating aquaculture system for 98 days to investigate effects of 0.3 mg/L Cu on its performance, Cu budget, and Cu distribution. Shrimps in Cu-treated systems had greater mean final weight (11.10 vs 10.50 g), body length (107.23 vs 106.42 mm), survival rate (67.80% vs 66.40%), and yield (6.42 vs 5.99 kg/m3), and lower feed conversion ratio (1.20 vs 1.29) than those in control systems but the differences were not significant. Vibrio numbers remained stable (104-106 colony forming units/mL) in the rearing tanks of both control and treated systems. Total ammonium-N, nitrite-N, nitrate-N, pH, chemical oxygen demand, 5-day carbonaceous biochemical oxygen demand, and total suspended solids were similar in controls and treatments. Dissolved Cu concentration in the treated systems decreased from 0.284 to 0.089 mg/L while in the control systems it increased from 0.006 2 to 0.018 mg/L. The main sources of Cu in the treated systems were the artificially added component (75.7% of total input), shrimp feed (21.0%), water (2.06%), and shrimp biomass (1.22%). The major outputs of Cu occurred via the mechanical filter (41.7%), water renewal (15.6%), and draining of the sediment trap (15.1%). The foam fractionator removed only 0.69% of total Cu input. Harvested shrimp biomass accounted for 11.68% of Cu input. The Cu concentration of shrimps in the Cu-treated systems (30.70 mg/kg wet weight) was significantly higher than that in control systems (22.02 mg/kg). Both were below the maximum permissible concentration (50 mg/kg) for Cu in seafood for human consumption in China. Therefore, recirculating systems can be used for commercial on-growing of Litopenaeus vannamei without loss of shrimp quality, even in water polluted by 0.30 mg/L Cu. The mechanical filter is the main route for Cu removal.

  4. Real Closed Rings and Real Closed * Rings

    OpenAIRE

    Capco, Jose

    2007-01-01

    Here we try to distinguish and compare different notions of real closedness mainly one developed by N. Schwartz in his Habilitationschrift and the other developed by A. Sankaranand K. Varadarajan which we shall call real closed *. We stick to the definition of real closed rings as defined and characterized N. Schwartz and we try to determine and characterize real closed rings that are real closed *. The main result is that real closed rings have unique real closure * and that real closure of ...

  5. An analysis of the thermodynamic efficiency for exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB)

    International Nuclear Information System (INIS)

    Lee, Chang-Eon; Yu, Byeonghun; Lee, Seungro

    2015-01-01

    This study presents fundamental research on the development of a new boiler that is expected to have a higher efficiency and lower emissions than existing boilers. The thermodynamic efficiency of exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB) was calculated using thermodynamic analysis and was compared with other boilers. The results show the possibility of obtaining a high efficiency when the temperature of the exhaust gas is controlled within 50–60 °C because water in the exhaust gas is condensed within this temperature range. In addition, the enthalpy emitted by the exhaust gas for the new boiler is smaller because the amount of condensed water is increased by the high dew-point temperature and the low exhaust gas temperature. Thus, the new boiler can obtain a higher efficiency than can older boilers. The efficiency of the EGR-CWR-WHR CB proposed in this study is 93.91%, which is 7.04% higher than that of existing CB that is currently used frequently. - Highlights: • The study presents the development of a new boiler expected to have a high efficiency. • Thermodynamic efficiency of EGR-CWR-WHR condensing boiler was calculated. • Efficiency of EGR-CWR-WHR CB is 93.91%, which is 7.04% higher than existing CB

  6. Influence of increased exhaust gas recirculation ratio on the thermodynamic processes in CI DI engine

    Science.gov (United States)

    Pielecha, I.; Skowron, M.; Bueschke, W.; Cieślik, W.; Wisłocki, K.

    2016-09-01

    The aim of the conducted research was the thermodynamic identification of combustion process involving up to 50-60% recirculated exhaust gasses in compression ignition engine. The values of the respective indicators obtained for the high share of exhaust gasses in the cylinder were compared to the values obtained in the engine working without EGR. The research was conducted on the single-cylinder AVL 5804 engine equipped with recirculated gas cooling system. The conditions of combustion process were determined using indicators of engine operation and measurements of fast-varying cylinder pressure. The evaluation of the influence of different share of exhaust gases in the cylinder on the combustion course and heat release was conducted. As a result of the conducted research the possibility of utilizing the high share of exhaust gasses (50-60%) with simultaneous ecological benefits, not only in relation to nitrogen oxides, was demonstrated.

  7. Conservation principles suspended solids distribution modeling to support ATS introduction on a recirculating WWTP

    DEFF Research Database (Denmark)

    Gernaey, Krist Victor Bernard; Nielsen, M.K.; Thornberg, D.

    2004-01-01

    A model for the description of the SS distribution in a full-scale recirculating activated sludge WWTP was developed. The model, based on conservation principles, uses on-line plant data as model inputs, and provides a prediction of the SS load in the inlet to the secondary clarifiers and the SS...... distribution in the WWTP as outputs. The calibrated model produces excellent predictions of the SS load to the secondary clarifiers, an essential variable for the operation of the aeration tank settling (ATS) process. A case study illustrated how the calibrated SS distribution model can be used to evaluate...... the potential benefit of ATS implementation on a full-scale recirculating WWTP. A reduction of the maximum SS peak load to the secondary clarifiers with 24.9% was obtained with ATS, whereas the cumulative SS load to the clarifiers is foreseen to be reduced with 22.5% for short rain events (4 hours duration...

  8. Corrosion products, activity transport and deposition in boiling water reactor recirculation systems

    International Nuclear Information System (INIS)

    Alder, H.P.; Buckley, D.; Grauer, R.; Wiedemann, K.H.

    1992-01-01

    The deposition of activated corrosion products in the recirculation loops of Boiling Water Reactors produces increased radiation levels which lead to a corresponding increase in personnel radiation dose during shut down and maintenance. The major part of this dose rate is due to cobalt-60. Based on a comprehensive literature study concerning this theme, it has been attempted to identify the individual stages of the activity build-up and to classify their importance. The following areas are discussed in detail: The origins of the corrosion products and of cobalt-59 in the reactor feedwaters; the consolidation of the cobalt in the fuel pins deposits (activation); the release and transport of cobalt-60; the build-up of cobalt-60 in the corrosion products in the recirculation loops. Existing models of the build-up of circuit radioactivity are discussed and the operating experiences from selected reactors are summarized. 90 refs, figs and tabs

  9. Implementation of Exhaust Gas Recirculation for Double Stage Waste Heat Recovery System on Large Container Vessel

    DEFF Research Database (Denmark)

    Andreasen, Morten; Marissal, Matthieu; Sørensen, Kim

    2014-01-01

    to reach the highest possible combination of pressure and temperature, and adapted to Tier III by introducing two alternative superheaters. The system design is optimized and found capable of producing from 400 to 1900 kW, with a weighted average power of 958 kW. The consumption profile is found...... of recovering some of the waste heat from the exhaust gas. This heat is converted into electrical energy used on-board instead of using auxiliary engines. Exhaust Gas Recirculation (EGR) systems, are recirculating a part of the exhaust gas through the engine combustion chamber to reduce emissions. WHRS combined...... with EGR is a potential way to improve system efficiency while reducing emissions. This paper investigates the feasibility of combining the two systems. EGR dilutes the fuel, lowering the combustion temperature and thereby the formation of NOx, to reach Tier III limitation. A double stage WHRS is set up...

  10. Identification and origin of plant pathogenic microorganisms in recirculating nutrient solutions

    Science.gov (United States)

    Stanghellini, M. E.; Rasmussen, S. L.

    1994-11-01

    Avoidance of root-infecting microorganisms was originally considered one of the advantages of cultivation of crops in a soilless, recirculating nutrient solution. However, to date, four viral, three bacterial and 21 fungal pathogens have been identified as causal agents of root disease in hydroponically-grown crops. Root-infecting fungi, particularly those which produce a motile stage known as a zoospore, have been the primary pathogens associated with extensive crop losses. Documented sources of these root pathogens in hydroponic systems include peat, surface water such as rivers and streams, and insects. The severity of disease caused by these introduced root pathogens is primarily governed by the genetic susceptibility of each crop and the temperature of the recirculating nutrient solution.

  11. Modelling the HIV persistence through the network of lymphocyte recirculation in vivo

    Directory of Open Access Journals (Sweden)

    Ying Huang

    2017-02-01

    Full Text Available Human Immunodeficiency Virus (HIV is able to persist in cellular and/or anatomical viral reservoirs, despite the effective inhibition of virus replication by the antiretroviral therapy (ART. Here we develop a mathematical model to gain some insights of HIV persistence relevant to the lymphocyte recirculation network of immune system and the central nervous system (CNS. Our simulations and analyses illustrate the role of the CNS as a virus reservoir to prevent antiretroviral drugs from penetrating the blood-brain (or blood-testis barrier, and we examine the long-term impact of this reservoir on the transmissibility of an infected individual. We observe numerically that level of HIV in peripheral blood may not accurately reflect the true mechanisms occurring within other organs. Keywords: HIV reservoirs, Blood-brain barrier, Dynamical model, Lymphocyte recirculation network, 2010 MSC: 39A11, 92D30

  12. Improved sanitary landfill design using recirculation of anaerobically treated leachates: generation of advanced design criteria

    OpenAIRE

    Schiappacasse,María Cristina; Palma,Juan; Poirrier,Paola; Ruiz-Filippi,Gonzalo; Chamy,Rolando

    2010-01-01

    In Latin Americ a, the most accepted disposal systems for Municipal Solid Waste (MSW) are landfills, which nowadays have low rates of stabilization. The objective of this study was to develop design criteria for sanitary landfills which lead to a reduction in the stabilization times of MSW, based on experiment results obtain from a pre-pilot scale operation of two sanitary landfills (0.5 Ton), one with recirculation of leachates treated in an anaerobic digester and the other with recirculatio...

  13. Horticultural Producers' Willingness to Adopt Water Recirculation Technology in the Mid-Atlantic Region

    OpenAIRE

    Cultice, Alyssa K.; Bosch, Darrell J.; Pease, James W.; Boyle, Kevin J.

    2013-01-01

    In response to economic and environmental concerns, Water-Recycling Technologies (WRT) have been developed to reduce water consumption and surface run-off in horticultural operations. Water recirculation provides the potential for water conservation and may also reduce grower costs in the long run. However, WRT comes with increased risk of disease from water-borne pathogens such as Pythium and Phytophthora, which can cause devastating plant losses. In addition, WRT entail infrastructure inves...

  14. Use of Segmented Cell Operated in Hydrogen Recirculation Mode to Detect Water Accumulation in PEMFC

    OpenAIRE

    Perez, L.C.; Ihonen J.; J. M. Sousa; Adélio Mendes

    2013-01-01

    Adequate water management is crucial to increase stability and durability of Polymer Electrolyte Membrane Fuel Cells. In this paper, a test rig suitable for water balance and nitrogen crossover studies was built around a hydrogen-air segmented cell and used to indirectly assess flooding or drying conditions in specific zones of the active cell area. In particular, the anode of the segmented cell was operated in recirculation mode with continuous water removal. Current density distribution (CD...

  15. Nonlinear Adaptive Control of Exhaust Gas Recirculation for Large Diesel Engines

    DEFF Research Database (Denmark)

    Nielsen, Kræn Vodder; Blanke, Mogens; Vejlgaard-Laursen, Morten

    2015-01-01

    A nonlinear adaptive controller is proposed for the exhaust gas recirculation systemon large two-stroke diesel engines. The control design is based on a control oriented model ofthe nonlinear dynamics at hand that incorporates load and engine speed changes as knowndisturbances to the exhaust gas...... will make the system converge exponentiallyto the best achievable state. Simulation examples confirm convergence and good disturbancerejection over relevant operational ranges of the engine....

  16. High power millimeter-wave free electron laser based on recirculating electrostatic accelerator

    International Nuclear Information System (INIS)

    Lee, Byung-Cheol; Kim, Sun-Kook; Jeong, Young-Uk; Cho, Sung-Oh; Lee, Jongmin

    1995-01-01

    Progress in the development of a high power, millimeter-wave free electron laser driven by a recirculating electrostatic accelerator is reported. The energy and the current of electron beam are 430 keV and 2 A, respectively. The expected average output power is above 10 kW at the wavelength of 3-10 mm. Minimizing of the beam loss is a key issue for CW operation of the FEL with high efficiency. (author)

  17. Study of recirculating induction accelerators as drivers for heavy ion fusion

    International Nuclear Information System (INIS)

    Barnard, J.J.; Brooks, A.L.; Clay, J.P.; Coffield, F.E.; Deadrick, F.J.; Griffith, L.V.; Harvey, A.R.; Kirbie, H.C.; Neil, V.K.; Newton, M.A.; Paul, A.C; Reginato, L.L.; Russell, G.E.; Sharp, W.M.; Shay, H.D.; Wilson, J.H.; Yu, S.S.; Judd, D.L.

    1991-01-01

    This report presents point designs for a recirculating induction accelerator that will function as the driver for an inertial confinement fusion reactor power plant that produces about 1 GW of electric power for a lifetime of about 30 years. The idea of a recirculator has been previously proposed but no integrated driver system has ever been conceptually designed or evaluated. Our goal is to present design examples that meet the requirements set by target and reactor physics while minimizing the cost and maximizing efficiency. We wish to evaluate the feasibility of such an accelerator by performing a preliminary analysis of the major physics and engineering issues. A further goal is to compare the cost and efficiency of this point design with that of a linear accelerator, similarly designed using the same costing algorithms. During the preparation of this report, new issues continually arose and appropriate solutions were devised. At times, different weights were given to the often conflicting goals of low cost, high efficiency, high confidence of achieving high beam quality at the target, and high confidence in technological achievability. We have therefore arrived at many point designs, three of which are the subject of this report: Today's Technology Design. This design is the primary focus of the report, and it consists entirely of technology that could be built today or soon. The Low Cost/Advanced Technology Design. This design uses more advanced or alternative technologies to implement the recirculator concept. The Low Physics Risk Design. In this design, the driver system consists of several independent single-beam recirculators, rather than allowing several beams to share an induction core

  18. Biofouling reduction in recirculating cooling systems through biofiltration of process water.

    Science.gov (United States)

    Meesters, K P H; Van Groenestijn, J W; Gerritse, J

    2003-02-01

    Biofouling is a serious problem in industrial recirculating cooling systems. It damages equipment, through biocorrosion, and causes clogging and increased energy consumption, through decreased heat transfer. In this research a fixed-bed biofilter was developed which removed assimilable organic carbon (AOC) from process water, thus limiting the major substrate for the growth of biofouling. The biofilter was tested in a laboratory model recirculating cooling water system, including a heat exchanger and a cooling tower. A second identical model system without a biofilter served as a reference. Both installations were challenged with organic carbon (sucrose and yeast extract) to provoke biofouling. The biofilter improved the quality of the recirculating cooling water by reducing the AOC content, the ATP concentration, bacterial numbers (30-40 fold) and the turbidity (OD660). The process of biofouling in the heat exchangers, the process water pipelines and the cooling towers, was monitored by protein increase, heat transfer resistance, and chlorine demanded for maintenance. This revealed that biofouling was lower in the system with the biofilter compared to the reference installation. It was concluded that AOC removal through biofiltration provides an attractive, environmental-friendly means to reduce biofouling in industrial cooling systems.

  19. Analysis of the sodium recirculation theory of solute-coupled water transport in small intestine.

    Science.gov (United States)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkaer

    2002-07-01

    Our previous mathematical model of solute-coupled water transport through the intestinal epithelium is extended for dealing with electrolytes rather than electroneutral solutes. A 3Na+-2K+ pump in the lateral membranes provides the energy-requiring step for driving transjunctional and translateral flows of water across the epithelium with recirculation of the diffusible ions maintained by a 1Na+-1K+-2Cl- cotransporter in the plasma membrane facing the serosal compartment. With intracellular non-diffusible anions and compliant plasma membranes, the model describes the dependence on membrane permeabilities and pump constants of fluxes of water and electrolytes, volumes and ion concentrations of cell and lateral intercellular space (lis), and membrane potentials and conductances. Simulating physiological bioelectrical features together with cellular and paracellular fluxes of the sodium ion, computations predict that the concentration differences between lis and bathing solutions are small for all three ions. Nevertheless, the diffusion fluxes of the ions out of lis significantly exceed their mass transports. It is concluded that isotonic transport requires recirculation of all three ions. The computed sodium recirculation flux that is required for isotonic transport corresponds to that estimated in experiments on toad small intestine. This result is shown to be robust and independent of whether the apical entrance mechanism for the sodium ion is a channel, a SGLT1 transporter driving inward uphill water flux, or an electroneutral Na+-K+-2Cl- cotransporter.

  20. Anaerobic digestion of food waste - Effect of recirculation and temperature on performance and microbiology.

    Science.gov (United States)

    Zamanzadeh, Mirzaman; Hagen, Live H; Svensson, Kine; Linjordet, Roar; Horn, Svein J

    2016-06-01

    Recirculation of digestate was investigated as a strategy to dilute the food waste before feeding to anaerobic digesters, and its effects on microbial community structure and performance were studied. Two anaerobic digesters with digestate recirculation were operated at 37 °C (MD + R) and 55 °C (TD + R) and compared to two additional digesters without digestate recirculation operated at the same temperatures (MD and TD). The MD + R digester demonstrated quite stable and similar performance to the MD digester in terms of the methane yield (around 480 mL CH4 per gVSadded). In both MD and MD + R Methanosaeta was the dominant archaea. However, the bacterial community structure was significantly different in the two digesters. Firmicutes dominated in the MD + R, while Chloroflexi was the dominant phylum in the MD. Regarding the thermophilic digesters, the TD + R showed the lowest methane yield (401 mL CH4 per gVSadded) and accumulation of VFAs. In contrast to the mesophilic digesters, the microbial communities in the thermophilic digesters were rather similar, consisting mainly of the phyla Firmicutes, Thermotoga, Synergistetes and the hydrogenotrophic methanogen Methanothermobacter. The impact of ammonia inhibition was different depending on the digesters configurations and operating temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. A ZigBee Wireless Sensor Network for Monitoring an Aquaculture Recirculating System

    Directory of Open Access Journals (Sweden)

    Francisco J. Espinosa-Faller

    2012-06-01

    Full Text Available A ZigBee wireless sensor network was developed for monitoring an experimental aquaculture recirculating system.Temperature, dissolved oxygen, water and air pressure as well as electric current sensors were included in the setup.The high fish densities required in these systems to become economically viable present a case where sensornetworks can be applied to preserve a healthy livestock and to reduce the risk of failures that end up in the loss ofproduction. Modules for reading and transmitting sensor values through a ZigBee wireless network were developedand tested. The modules were installed in an aquaculture recirculating system to transmit sensor values to thenetwork coordinator. A monitoring program was created in order to display and store sensor values and to comparethem with reference limits. An alert is emitted in case reference limits have been reached. E-mail and an SMSmessage alert can also be sent to the cellular phone of the system administrator, so immediate action can be taken. Aweb interface allows Internet access to the sensor values. The present work demonstrates the applicability of ZigBeewireless sensor network technology to aquaculture recirculating systems.

  2. Two-phase flow phenomena in broken recirculation line of BWR

    International Nuclear Information System (INIS)

    Kato, Masami; Arai, Kenji; Narabayashi, Tadashi; Amano, Osamu.

    1986-01-01

    When a primary recirculation line of BWR is ruptured, a primary recirculation pump may be subjected to very high velocity two-phase flow and its speed may be accelerated by this flow. It is important for safety evaluation to estimate the pump behavior during blowdown. There are two problems involved in analyzing this behavior. One problem concerns the pump characteristics under two-phase flow. The other involves the two-phase conditions at the pump inlet. If the rupture occurs at a suction side of the pump, choking is considered to occur at a broken jet pump nozzle. Then, a void fraction becomes larger downstream from the jet pump nozzle and volumetric flow through the pump will be very high. However, there is little experimental data available on two-phase flow downstream from a choking plane. Blowdown tests were performed using a simulated broken recirculation line and measured data were analyzed by TRAC-PlA. Analytical results agreed with measured data. (author)

  3. Digital controller for feedwater and recirculation flow control of BWR plant

    International Nuclear Information System (INIS)

    Sato, Takao; Ito, Tetsuo; Omori, Takashi; Iida, Hiroshi; Yanai, Katsuya.

    1980-01-01

    In nuclear power plants, it is required to operate the plants on load-following basis as the proportion of nuclear power plants in whole power supply network has been increasing. For this purpose, the requirements of more reliable, more automated plants and of the flexibility of operation are becoming serious. To respond to such demands, digital controllers are inevitable because analog controllers are limited in their controllability. It is also required to devise more intelligent systems such as those enabling strengthened diagnostic functions or sophisticated predictive control. On such background, duplicated redundant digital control system has been developed, using two control microcomputers and uniting the conventional feed-water control system and recirculation flow control system. The report discribes on the design concept for this digital controller, the hardware and software of the control system and the confirmation of the performance by simulation. The verifying test for the control performance, the simulation test for recirculation pump abnormality, the test for predictive control and the test on the response characteristics of recirculation system were carried out. The digital controller attained the MTBF 10 times as much, and the down time ratio 1/5 as small as those of the analog control systems. (Wakatsuki, Y.)

  4. Open-RAC: Open-Design, Recirculating and Auto-Cleaning Zebrafish Maintenance System.

    Science.gov (United States)

    Nema, Shubham; Bhargava, Yogesh

    2017-08-01

    Zebrafish is a vertebrate animal model. Their maintenance in large number under laboratory conditions is a daunting task. Commercially available recirculating zebrafish maintenance systems are used to efficiently handle the tasks of automatic sediment cleaning from zebrafish tanks with minimal waste of water. Due to their compact nature, they also ensure the maximal use of available lab space. However, the high costs of commercial systems present a limitation to researchers with limited funds. A cost-effective zebrafish maintenance system with major features offered by commercially available systems is highly desirable. Here, we describe a compact and recirculating zebrafish maintenance system. Our system is composed of cost-effective components, which are available in local markets and/or can be procured via online vendors. Depending on the expertise of end users, the system can be assembled in 2 days. The system is completely customizable as it offers geometry independent zebrafish tanks that are capable of auto-cleaning the sediments. Due to these features, we called our setup as Open-RAC (Open-design, Recirculating and Auto-Cleaning zebrafish maintenance system). Open-RAC is a cost-effective and viable alternative to the currently available zebrafish maintenance systems. Thus, we believe that the use of Open-RAC could promote the zebrafish research by removing the cost barrier for researchers.

  5. Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary and Crystalline Formations

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Mike S. [Terralog Technologies USA, Inc., Calgary (Canada); Detwiler, Russell L. [Terralog Technologies USA, Inc., Calgary (Canada); Lao, Kang [Terralog Technologies USA, Inc., Calgary (Canada); Serajian, Vahid [Terralog Technologies USA, Inc., Calgary (Canada); Elkhoury, Jean [Terralog Technologies USA, Inc., Calgary (Canada); Diessl, Julia [Terralog Technologies USA, Inc., Calgary (Canada); White, Nicky [Terralog Technologies USA, Inc., Calgary (Canada)

    2012-12-13

    There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. The primary objectives of this DOE research effort are to develop and document optimum design configurations and operating practices to produce geothermal power from hot permeable sedimentary and crystalline formations using advanced horizontal well recirculation systems. During Phase I of this research project Terralog Technologies USA and The University of California, Irvine (UCI), have completed preliminary investigations and documentation of advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. We have also identified significant geologic resources appropriate for application of such technology. The main challenge for such recirculation systems is to optimize both the design configuration and the operating practices for cost-effective geothermal energy recovery. These will be strongly influenced by sedimentary formation properties, including thickness and dip, temperature, thermal conductivity, heat capacity, permeability, and porosity; and by working fluid properties.

  6. Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Richard Turton; Chamila Tissera; Emre Tatli; Andy Zimmerman

    2005-12-28

    Selective NOx Recirculation (SNR) involves cooling the engine exhaust gas and then adsorbing the oxides of nitrogen (NOx) from the exhaust stream, followed by the periodic desorption of NOx. By returning the desorbed, concentrated NOx into the engine intake and through the combustion chamber, a percentage of the NOx is decomposed during the combustion process. An initial study of NOx decomposition during lean-burn combustion was concluded in 2004 using a 1993 Cummins L10G 240hp natural gas engine. It was observed that the air/fuel ratio, injected NO (nitric oxide) quantity and engine operating points affected NOx decomposition rates of the engine. Chemical kinetic modeling results were also used to determine optimum NOx decomposition operating points and were published in the 2004 annual report. A NOx decomposition rate of 27% was measured from this engine under lean-burn conditions while the software model predicted between 35-42% NOx decomposition for similar conditions. A later technology 1998 Cummins L10G 280hp natural gas engine was procured with the assistance of Cummins Inc. to replace the previous engine used for 2005 experimental research. The new engine was equipped with an electronic fuel management system with closed-loop control that provided a more stable air/fuel ratio control and improved the repeatability of the tests. The engine was instrumented with an in-cylinder pressure measurement system and electronic controls, and was adapted to operate over a range of air/fuel ratios. The engine was connected to a newly commissioned 300hp alternating current (AC) motoring dynamometer. The second experimental campaign was performed to acquire both stoichiometric and slightly rich (0.97 lambda ratio) burn NOx decomposition rates. Effects of engine load and speed on decomposition were quantified, but Exhaust Gas Recirculation (EGR) was not varied independently. Decomposition rates of up to 92% were demonstrated. Following recommendations at the 2004 ARES peer

  7. Investigating the influence of nitrate nitrogen on post-smolt Atlantic salmon Salmo salar reproductive physiology in water recirculation aquaculture systems

    Science.gov (United States)

    Good, Christopher; Davidson, John; Iwanowicz, Luke; Meyer, Michael T.; Dietze, Julie E.; Kolpin, Dana W.; Marancik, David; Birkett, Jill; Williams, Christina; Summerfelt, Steven T.

    2017-01-01

    A major issue affecting land-based, closed containment Atlantic salmon Salmo salar growout production in water recirculation aquaculture systems (RAS) is precocious male maturation, which can negatively impact factors such as feed conversion, fillet yield, and product quality. Along with other water quality parameters, elevated nitrate nitrogen (NO3-N) has been shown to influence the reproductive development and endogenous sex steroid production in a number of aquatic animal species, including Atlantic salmon. We sought to determine whether elevated NO3-N in RAS can influence early maturation in post-smolt Atlantic salmon in an 8-month trial in replicated freshwater RAS. Post-smolt Atlantic salmon (102 ± 1 g) were stocked into six RAS, with three RAS randomly selected for dosing with high NO3-N (99 ± 1 mg/L) and three RAS set for low NO3-N (10 ± 0 mg/L). At 2-, 4-, 6-, and 8-months post-stocking, 5 fish were randomly sampled from each RAS, gonadosomatic index(GSI) data were collected, and plasma was sampled for 11-ketotestosterone(11-KT) quantification. At 4- and 8-months post-stocking, samples of culture tank and spring water (used as “makeup” or replacement water) were collected and tested for a suite of 42 hormonally active compounds using liquid chromatography/mass spectrometry, as well as for estrogenicity using the bioluminescent yeast estrogen screen (BLYES) reporter system. Finally, at 8-months post-stocking 8–9 salmon were sampled from each RAS for blood gas and chemistry analyses, and multiple organ tissues were sampled for histopathology evaluation. Overall, sexually mature males were highly prevalent in both NO3-N treatment groups by study’s end, and there did not appear to be an effect of NO3-N on male maturation prevalence based on grilse identification, GSI, and 11-KT results, indicating that other culture parameters likely instigated early maturation. No important differences were noted between treatment groups for

  8. Effects of recirculation in a three-tank pilot-scale system for pharmaceutical removal with powdered activated carbon.

    Science.gov (United States)

    Kårelid, Victor; Larsson, Gen; Björlenius, Berndt

    2017-05-15

    The removal of pharmaceutically active compounds by powdered activated carbon (PAC) in municipal wastewater is a promising solution to the problem of polluted recipient waters. Today, an efficient design strategy is however lacking with regard to high-level overall, and specific, substance removal in the large scale. The performance of PAC-based removal of pharmaceuticals was studied in pilot-scale with respect to the critical parameters; contact time and PAC dose using one PAC product selected by screening in bench-scale. The goal was a minimum of 95% removal of the pharmaceuticals present in the evaluated municipal wastewater. A set of 21 pharmaceuticals was selected from an initial 100 due to their high occurrence in the effluent water of two selected wastewater treatment plants (WWTPs) in Sweden, whereof candidates discussed for future EU regulation directives were included. By using recirculation of PAC over a treatment system using three sequential contact tanks, a combination of the benefits of powdered and granular carbon performance was achieved. The treatment system was designed so that recirculation could be introduced to any of the three tanks to investigate the effect of recirculation on the adsorption performance. This was compared to use of the setup, but without recirculation. A higher degree of pharmaceutical removal was achieved in all recirculation setups, both overall and with respect to specific substances, as compared to without recirculation. Recirculation was tested with nominal contact times of 30, 60 and 120 min and the goal of 95% removal could be achieved already at the shortest contact times at a PAC dose of 10-15 mg/L. In particular, the overall removal could be increased even to 97% and 99%, at 60 and 120 min, respectively, when the recirculation point was the first tank. Recirculation of PAC to either the first or the second contact tank proved to be comparable, while a slightly lower performance was observed with recirculation to

  9. The effect of sludge recirculation rate on a UASB-digester treating domestic sewage at 15 °C.

    Science.gov (United States)

    Zhang, Lei; Hendrickx, Tim L G; Kampman, Christel; Zeeman, Grietje; Temmink, Hardy; Li, Weiguang; Buisman, Cees J N

    2012-01-01

    The anaerobic treatment of low strength domestic sewage at low temperature is an attractive and important topic at present. The upflow anaerobic sludge bed (UASB)-digester system is one of the anaerobic systems to challenge low temperature and concentrations. The effect of sludge recirculation rate on a UASB-digester system treating domestic sewage at 15 °C was studied in this research. A sludge recirculation rate of 0.9, 2.6 and 12.5% of the influent flow rate was investigated. The results showed that the total chemical oxygen demand (COD) removal efficiency rose with increasing sludge recirculation rate. A sludge recirculation rate of 0.9% of the influent flow rate led to organic solids accumulation in the UASB reactor. After the sludge recirculation rate increased from 0.9 to 2.6%, the stability of the UASB sludge was substantially improved from 0.37 to 0.15 g CH₄-COD/g COD, and the bio-gas production in the digester went up from 2.9 to 7.4 L/d. The stability of the UASB sludge and bio-gas production in the digester were not significantly further improved by increasing sludge recirculation rate to 12.5% of the influent flow rate, but the biogas production in the UASB increased from 0.37 to 1.2 L/d. It is recommended to apply a maximum sludge recirculation rate of 2-2.5% of the influent flow rate in a UASB-digester system, as this still allows energy self-sufficiency of the system.

  10. Treatment of rosacea patients with broadband pulse light emission using smooth pulse and photon recirculation technologies

    Directory of Open Access Journals (Sweden)

    A. A. Kubanova

    2015-01-01

    Full Text Available Goal of the study. To assess the efficacy and safety of using broadband pulse light emission with smooth pulse and photon recirculation technologies in the treatment of patients suffering from erythematous and papulous subtypes of rosacea. Materials and methods. Sixty rosacea patients (21 male and 39 female at the age of 25-65 including 38 patients with erythematous and 22 patients with papulous subtypes of rosacea underwent treatment using broadband pulse light emission (5-8 treatment sessions. Results. After one month of treatment with broadband pulse light emission using smooth pulse and photon recirculation technologies: 68.4% of patients with the erythematous subtype had clinical recovery, and 31.6% - improvement; 27.2% of patients with the papulous subtype - clinical recovery, 54.5% - improvement, and 18.3% had no effect. After 5 months of treatment most of the patients still had a positive effect of the therapy, yet 21.1% of patients with the erythematous subtype and 11% of patients with the papulous subtype had single telangiectasias, increased erythema and single papules. After 10 months of treatment 44.7% of patients with the erythematous subtype of rosacea had an increase in the number of enlarged vessels, and 18.3% of patients with the papulous subtype had signs of a recurrence of the disease. Conclusion. The use of broadband pulse light emission with smooth pulse and photon recirculation technologies has a multiple, painless and significant effect on large lesions in the treatment of patients suffering from erythematous and papulous subtypes of rosacea.

  11. Partitioning sources of recharge in environments with groundwater recirculation using carbon-14 and CFC-12

    Science.gov (United States)

    Bourke, Sarah A.; Cook, Peter G.; Dogramaci, Shawan; Kipfer, Rolf

    2015-06-01

    Groundwater recirculation occurs when groundwater is pumped from an aquifer onto the land surface, and a portion of that water subsequently infiltrates back to the aquifer. In environments where groundwater is recirculated, differentiation between various sources of recharge (e.g. natural rainfall recharge vs. recirculated water) can be difficult. Groundwater age indicators, in particular transient trace gases, are likely to be more sensitive tracers of recharge than stable isotopes or chloride in this setting. This is because, unlike stable isotopes or chloride, they undergo a process of equilibration with the atmosphere, and historical atmospheric concentrations are known. In this paper, groundwater age indicators (14C and CFC-12) were used as tracers of recharge by surplus mine water that is discharged to streams. Ternary mixing ratios were calculated based on 14C and CFC-12 concentrations measured along three transects of piezometers and monitoring wells perpendicular to the creeks, and from dewatering wells. Uncertainty in calculated mixing ratios was estimated using a Monte Carlo approach. Ternary mixing ratios in dewatering wells suggest that recharge by mine water accounted for between 10% and 87% of water currently abstracted by dewatering wells. The calculated mixing ratios suggest that recharge by mine water extends to a distance of more than 550 m from the creeks. These results are supported by seepage flux estimates based on the water and chloride balance along the creeks, which suggest that 85-90% of mine water discharged to the creeks recharges the aquifer and recharge by mine water extends between 110 and 730 m from the creeks. Mixing calculations based on gaseous groundwater age indicators could also be used to partition recharge associated with agricultural irrigation or artificial wetland supplementation.

  12. One- and two-phase anaerobic digestion of ley crop silage with and without liquid recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Nordberg, Aa.

    1996-10-01

    In this study the effects of liquid recirculation on hydrolysis and methanogenesis in one- and two-phase biogas processes were investigated in comparison with water-diluted processes. The operation of a water-diluted one-phase process resulted in process imbalances at a low loading rate. In a water-diluted two-phase process the fibre degrading capability was lost. The reason for the poor process performance was due to a deficiency in trace elements, since the supplementation of cobalt resulted in an increased conversion rate of acetate. The recirculation of process liquid resulted in an accumulation of different compounds which initially stabilized one-phase processes and stimulated the hydrolysis and the methane production in the liquefaction-acidogenesis stage of a two-phase process. However, upon continuous recirculation the concentration of free ammonia reached toxic levels, which resulted in a decrease in the methane yield both in the methanogenic reactor of the two-phase process and in the one-phase process. Due to the decreased methane production, acids started to accumulate which subsequently inhibited the hydrolysis in the one-phase process. The systematic variation in the processes were evaluated using principal component analysis and principal component regression. The interpretation of the dynamic behaviour of the processes was facilitated by the use of score plots and loading plots. The results indicate that ley crops do not meet the nutrient requirements of the bacteria in anaerobic digestion. Thus, the low content of trace elements and the high content of protein which subsequently will cause toxic levels of ammonia in digesting system with low water consumption, suggests co-digestion with supplementary feedstocks. 95 refs, 5 figs, 3 tabs

  13. Reliability analysis of air recirculation and-refrigeration systems of Angra-1 reactor containment

    International Nuclear Information System (INIS)

    Fernandes Filho, T.L.

    1982-10-01

    A reliability analysis of the air refrigeration and recirculation containment systems (ARRCS) of Angra-1 nuclear power plants, were done. The fault tree analysis was used. The failure primary data were taken out of Wash-1400 and IEEE. These data were processed by these following computer codes : Prep-Kitt, Sample, Trebil, Cressex and Streusl for the two stages of ARRCS operation. The design bases accident studied was a LOCA (loss of coolant). The component that more contribution give to the non-availability of ARRCS is the motor of the ARRCS. (E.G.) [pt

  14. Alternative Solution for Consumption Hot Water Recirculation for the Civil Buildings

    Directory of Open Access Journals (Sweden)

    Theodor Mateescu

    2007-01-01

    Full Text Available The sanitary comfort and the effective cost of maintenance in the civil buildings (block of flats are badly affected by the absence of the consumption hot water recirculation. From the technical point of view, the classical solution imposes the doubling of the transport and distribution pipes on the entire route, between the source and the consumption points. The materialization of the solution requires important financial investment, discouraging most of the time and the postponement of the problem solving with important consequences. This paper proposes an alternative technical solution which limits to a minimum the intervention, only in the interior hot water distribution system.

  15. Effect of internal recirculation velocity in an anaerobic sequencing batch reactor (ASBR

    Directory of Open Access Journals (Sweden)

    G. Z. Maurina

    2014-12-01

    Full Text Available This paper discusses the effect of different internal recirculation velocities on the mixture and shear stress on the flocs in an anaerobic sequencing batch reactor (ASBR. Thus, simulations are performed using a computational fluid dynamics (CFD tool to evaluate this dependency. The analysis of velocities and turbulent kinetic energy indicates that the highest flow evaluated (0.003 m³/s results in better mixing within the reactor. However, care must be taken with the recycling pipe size, in order to maintain the shear stress inside the range of optimal values.

  16. Recirculating Beam Breakup Study for the 12 GeV Upgrade at Jefferson Lab

    International Nuclear Information System (INIS)

    Shin, Ilkyoung; Satogata, Todd; Ahmed, Shahid; Bogacz, Slawomir; Stirbet, Mircea; Wang, Haipeng; Wang, Yan; Yunn, Byung; Bodenstein, Ryan

    2012-01-01

    Two new high gradient C100 cryomodules with a total of 16 new cavities were installed at the end of the CEBAF south linac during the 2011 summer shutdown as part of the 12-GeV upgrade project at Jefferson Lab. We surveyed the higher order modes (HOMs) of these cavities in the Jefferson Lab cryomodule test facility and CEBAF tunnel. We then studied recirculating beam breakup (BBU) in November 2011 to evaluate CEBAF low energy performance, measure transport optics, and evaluate BBU thresholds due to these HOMs. This paper discusses the experiment setup, cavity measurements, machine setup, optics measurements, and lower bounds on BBU thresholds by new cryomodules.

  17. Recirculating Beam Breakup Study for the 12 GeV Upgrade at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Ilkyoung Shin, Todd Satogata, Shahid Ahmed, Slawomir Bogacz, Mircea Stirbet, Haipeng Wang, Yan Wang, Byung Yunn, Ryan Bodenstein

    2012-07-01

    Two new high gradient C100 cryomodules with a total of 16 new cavities were installed at the end of the CEBAF south linac during the 2011 summer shutdown as part of the 12-GeV upgrade project at Jefferson Lab. We surveyed the higher order modes (HOMs) of these cavities in the Jefferson Lab cryomodule test facility and CEBAF tunnel. We then studied recirculating beam breakup (BBU) in November 2011 to evaluate CEBAF low energy performance, measure transport optics, and evaluate BBU thresholds due to these HOMs. This paper discusses the experiment setup, cavity measurements, machine setup, optics measurements, and lower bounds on BBU thresholds by new cryomodules.

  18. Exhaust Recirculation Control for Reduction of NOx from Large Two-Stroke Diesel Engines

    DEFF Research Database (Denmark)

    Nielsen, Kræn Vodder

    the automotive industry, but have only recently been introduced commercially to large two-stroke diesel engines. Recirculation of exhaust gas to the cylinders lowers the oxygen availability and increases the heat capacity during combustion, which in turn leads to less formation of NOx. Experience shows...... for the scavenge oxygen fraction is designed. This observer compensates for a significant delay in the oxygen sensor, and observer errors are proven to converge exponentially. By inverting part of the reduced model and using the parameter observer, a novel scavenge oxygen controller based on nonlinear adaptive...

  19. Ozonation control and effects of ozone on water quality in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Rojas-Tirado, Paula Andrea; Chetri, Ravi K.

    2018-01-01

    To address the undesired effect of chemotherapeutants in aquaculture, ozone has been suggested as an alternative to improve water quality. To ensure safe and robust treatment, it is vital to define the ozone demand and ozone kinetics of the specific water matrix to avoid ozone overdose. Different...... ozone dosages were applied to water in freshwater recirculating aquaculture systems (RAS). Experiments were performed to investigate ozone kinetics and demand, and to evaluate the effects on the water quality, particularly in relation to fluorescent organic matter. This study aimed at predicting...

  20. Char-recirculation biomass gasification system--a site-specific feasibility study

    International Nuclear Information System (INIS)

    Purdy, K.R.; Kerr, C.P.; Hensley, B.D.

    1991-01-01

    A site-specific feasibility study was conducted for a char-recirculation biomass gasification plant which would dispose of the chippable solid residues of the area sawmills. The plant would receive green hardwood chips and convert them into active charcoal while producing process steam and electrical power. An economic analysis was performed on the basis of not-for-profit operation, marketing crushed active charcoal to a broker at a discounted price, and displacing purchased electric power. Given a market for the active charcoal, the plant was judged to be economically viable

  1. A Study of NO{sub x} Reduction by Fuel Injection Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Feese, J.J.; Turns, S.R.

    1996-08-01

    Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO{sub X}) in industrial burner applications. Recent small- and large-scale experiments in natural-gas fired boilers have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO{sub X}, per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. The objective of the present investigation is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO{sub X} reduction observed between FIR and FGR by studying laminar diffusion flames. The purpose of studying laminar flames is to isolate chemical effects from the effects of turbulent mixing and heat transfer, which are inherent in practical boilers. Numerical simulations of H{sub 2}-air and CH{sub 4}-air counterflow diffusion flames using full kinetics were performed and NO{sub X} emission indices calculated for various conditions. Studies were conducted in which a N{sub 2} diluent was added either on the fuel- or air-side of the flame for conditions of either fixed initial velocities or fixed fuel mass flux. Results from these simulation studies indicate that a major factor in diluent effectiveness is the differential effect on flame zone residence times associated with fuel-side verses air-side dilution. Simulations in which flow velocities were fixed as diluent was added either to the air or fuel stream showed lower NO{sub X} emissions for air-side dilution; however, if instead, fuel mass fluxes were fixed as diluent was added, which results in an increase in the velocity of the streams, fuel-side dilution was more effective. These results were independent of whether H{sub 2} or Ch

  2. An RF-gun-driven recirculated linac as injector and FEL driver

    CERN Document Server

    Andersson, A; Werin, S; Biedron, S G; Freund, H

    2000-01-01

    A new pre-injector for the MAX-Laboratory is under design and construction. A thermionic RF gun, designed to operate at medium currents with low back bombardment power, is under construction. The gun will, via a magnetic compressor and energy filter, feed a recirculated linac consisting of two SLED-equipped structures giving 125 MeV each. The first will be delivered in 1999. The system is aimed as a pre-injector for the existing storage rings at MAX-Lab, but will also open up possibilities for a SASE FEL in the UV reaching above 100 MW below 100 nm.

  3. Three-dimensional thermal-hydraulic calculations to support recirculating steam generator design

    International Nuclear Information System (INIS)

    Carlucci, L.N.

    1987-01-01

    This paper describes a number of applications of the THIRST thermal-hydraulics code to help resolve potential performance and reliability problems related to flow and energy maldistributions on the shell-side of recirculating steam generators. The applications considered are: flow-induced vibration of U-bend tubes subjected to non-uniform two-phase cross-flow, optimization of flow distribution baffle designs to maximize flow penetration of the tube bundle above the tubesheet and assessment of non-uniform steam-water separator loadings

  4. Reduction of indoor particles concentration using re-circulating filtration units in Danish dwellings

    DEFF Research Database (Denmark)

    Spilak, Michal; Frederiksen, Marie; Karottki, Gabriela D.

    2012-01-01

    air was recirculated through the unit during two weeks in a randomized and double blinded design. The measurements included concentration of PM2.5 and ultrafine particles (UPC), carbon dioxide, temperature and relative humidity, ventilation, air flow through the unit, allergen and fungal levels....... Additional information was collected through questionnaires. Several medical tests were made, however the results are not included in this paper. Preliminary results showed significant decrease in PM2.5 concentration during the filtered period compared to placebo period. Likewise was UPC significantly lower...

  5. Extracorporeal albumin dialysis with the molecular adsorbent recirculating system in acute-on-chronic liver failure

    DEFF Research Database (Denmark)

    Bañares, Rafael; Nevens, Frederik; Larsen, Fin Stolze

    2013-01-01

    Acute-on-chronic liver failure (ACLF) is a frequent cause of death in cirrhosis. Albumin dialysis with the molecular adsorbent recirculating system (MARS) decreases retained substances and improves hemodynamics and hepatic encephalopathy (HE). However, its survival impact is unknown. In all, 189...... sessions were scheduled. The main endpoint was 28-day ITT and PP survival. There were no significant differences at inclusion, although the proportion of patients with Model for Endstage Liver Disease (MELD) score over 20 points and with spontaneous bacterial peritonitis (SBP) as a precipitating event...

  6. Environmental impact assessment of leachate recirculation in landfill of municipal solid waste by comparing with evaporation and discharge (EASEWASTE)

    DEFF Research Database (Denmark)

    Xing, Wei; Lu, Wenjing; Zhao, Yan

    2013-01-01

    In some arid regions where landfill produces minimal amount of leachate, leachate recirculation is suggested as a cost-effective option. However, its long-term impacts to environment remain disputed. For the purpose of revealing the environmental impacts of leachate recirculation in landfill, four...... scenarios were modeled using EASEWASTE, comparing the strategies of leachate recirculation (with or without gas management), evaporation and discharge. In the current situation (Scenario A), a total of 280t of waste was generated and then transported to a conventional landfill for disposal. A number...... of contaminants derived from waste can be stored in the landfill for long periods, with 11.69 person equivalent (PE) for stored ecotoxicity in water and 29.62 PE for stored ecotoxicity in soil, considered as potential risks of releasing to the environment someday. Meanwhile, impacts to ecotoxicity and human...

  7. Optimizing cost and minimizing energy loss in the recirculating race-track design of the LHeC electron linac

    CERN Document Server

    Skrabacz, J

    2008-01-01

    The objective of this project is to propose an optimal design of a recirculating electron linac for a future LHC-based e-p collider_the LHeC [1, 2]. Primary considerations are the cost, structure, shape, and size of the recirculating track, the optimal number of revolutions through which the e-beam should be accelerated, and radiative energy loss in the bends. Secondary considerations are transverse emittance growth due to radiation, the number of dipoles needed in order to maintain an upper bound on the emittance growth, the average length of such dipoles, and the maximum bending dipole field needed to recirculate the beam. These effects will be studied macroscopically with respect to the overall structure, in that smaller effects related to machine optics of the lattice structure will be neglected. The scope of the optimization problem is, in essence, a "first order" insight into optimal dimensions, centered on minimizing the most important parameter_cost.

  8. Experiments investigating the effects of the accelerating gap voltage pulse on the ion focused (IFR) high current electron recirculators

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R.; Turman, B.N.; Prestwich, K.R.; Wells, J.

    1991-01-01

    The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for an open-ended, spiral recirculating electron linear accelerator. It dictates the number of allowable beam recirculations through the gap. In the case of a racetrack configuration, it is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. It was established that pulsing the accelerating gap perturbs the IFR channel. However, for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition, cusp fields positioned upstream and downstream from the gap prevent it from perturbing the IFR channel. 4 refs., 5 figs., 1 tab

  9. Experiments investigating the effects of the accelerating gap voltage pulse on the ion focused (IFR) high current electron recirculators

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.; Wagner, J.S.; Bennett, L.F.; Olson, W.R. Turnman, B.N.; Prestwich, K.R.; Wells, J.

    1991-01-01

    The lifetime of the Ion Focusing Regime (IFR) channel following the pulsing of the post-accelerating gaps is critical for an open-ended, spiral recirculating electron linear accelerator. It dictates the number of allowable beam recirculations through the gap. In the case of a racetrack configuration, its is significant but not as critical, since the presence of the electron beam focuses the ions and lengthens the lifetime of the ion channel. It was established that pulsing the accelerating gap perturbs the IFR channel. However, for the parameters studied, the lifetime is long enough to allow at least four beam recirculations in a spiral device. In addition, cusp fields positioned upstream and downstream from the gap prevent it from perturbing the IFR channel

  10. Experimental Gasification of Biomass in an Updraft Gasifier with External Recirculation of Pyrolysis Gases

    Directory of Open Access Journals (Sweden)

    Adi Surjosatyo

    2014-01-01

    Full Text Available The updraft gasifier is a simple type of reactor for the gasification of biomass that is easy to operate and has high conversion efficiency, although it produces high levels of tar. This study attempts to observe the performance of a modified updraft gasifier. A modified updraft gasifier that recirculates the pyrolysis gases from drying zone back to the combustion zone and gas outlet at reduction zone was used. In this study, the level of pyrolysis gases that returned to the combustion zone was varied, and as well as measurements of gas composition, lower heating value and tar content. The results showed that an increase in the amount of pyrolysis gases that returned to the combustion zone resulted in a decrease in the amount of tar produced. An increase in the amount of recirculated gases tended to increase the concentrations of H2 and CH4 and reduce the concentration of CO with the primary (gasification air flow held constant. Increasing the primary air flow tended to increase the amount of CO and decrease the amount of H2. The maximum of lower heating value was 4.9 MJ/m3.

  11. Conceptual design of the cryogenic system and estimation of the recirculated power for CFETR

    Science.gov (United States)

    Liu, Xiaogang; Qiu, Lilong; Li, Junjun; Wang, Zhaoliang; Ren, Yong; Wang, Xianwei; Li, Guoqiang; Gao, Xiang; Bi, Yanfang

    2017-01-01

    The China Fusion Engineering Test Reactor (CFETR) is the next tokamak in China’s roadmap for realizing commercial fusion energy. The CFETR cryogenic system is crucial to creating and maintaining operational conditions for its superconducting magnet system and thermal shields. The preliminary conceptual design of the CFETR cryogenic system has been carried out with reference to that of ITER. It will provide an average capacity of 75 to 80 kW at 4.5 K and a peak capacity of 1300 kW at 80 K. The electric power consumption of the cryogenic system is estimated to be 24 MW, and the gross building area is about 7000 m2. The relationships among the auxiliary power consumed by the cryogenic system, the fusion power gain and the recirculated power of CFETR are discussed, with the suggestion that about 52% of the electric power produced by CFETR in phase II must be recirculated to run the fusion test reactor.

  12. Leak before break analysis for cracking at multiple weld locations in BWR recirculation piping

    International Nuclear Information System (INIS)

    Zahoor, A.; Gamble, R.

    1984-01-01

    Periodically over the past decade, intergranular stress corrosion cracking (IGSCC) has been found in austenitic stainless steel piping at Boiling Water Reactor facilities. The effect of IGSCC on piping integrity has been evaluated previously in various BWR Owners Group and NRC studies. In these studies, the analyses were performed assuming the presence of a crack at a single weld location in the pipe run. The purpose of this investigation was to compare the leak rate and potential for unstable crack extension associated with a throughwall crack for the following two conditions in a BWR recirculation system: (1) the recirculation piping contains part through cracks at multiple weld locations and a single throughwall crack, and (2) the piping contains only a throughwall crack at one weld location. Two type BWRs were evaluated; namely, the ring header and five individual loop designs. The results from the analyses indicate that the potential for unstable crack extension at large bending loads, and leak rate at normal operation are not affected by the presence of part through cracks at multiple weld locations. The differences in the respective calculated L/sub eff/ and leak rates for the single and multiply cracked conditions are less than 2%

  13. The calibration of a cylindrical pressure probe for recirculating flow measurements

    International Nuclear Information System (INIS)

    Lawn, C.J.

    1975-06-01

    The use of the pressure distribution around a cylinder in cross-flow to indicate the magnitude and direction of the velocity vector is discussed in the context of making measurements in highly turbulent recirculating flows. The intended application is the measurement of the flow between the ribs on the large-scale model of the AGR fuel-pin surface. Results from a number of calibration experiments in boundary layers are used to provide a correlation for the positions at which local static pressure is measured on the cylinder surface. After appropriate corrections, the dynamic pressure is deduced from the pressure at the stagnation point. Corrections are also necessary in deducing the direction of flow from the bisector of the static pressure positions, when the cylinder is in a shear flow or near a wall, and these too are evaluated from the results of the calibration experiments. Measurements in two recirculating flows are then presented as an illustration both of the validity and limitations of the technique. In the first case, comparison is made with the measurements of a pulsed-wire anemometer behind a surface-mounted cube and, in the second, the continuity is used to provide an overall check on measurements behind a transverse plate. It is concluded that useful results can be obtained in many turbulent flow situations. (author)

  14. Viability of the vascularly perfused, recirculating rat intestine and intestine-liver preparations

    Energy Technology Data Exchange (ETDEWEB)

    Hirayama, H.; Xu, X.; Pang, K.S. (Univ. of Toronto, Ontario (Canada))

    1989-08-01

    Function and stability of vascularly perfused, recirculating in situ rat intestine (I) and intestine-liver (IL) preparations were evaluated in fasted and nonfasted rats because these techniques may be readily applied in drug metabolism studies. The rat intestine was perfused with blood medium (7.5 ml/min) via the superior mesenteric artery, with the venous outflow draining into the portal vein, which, together with hepatic arterial flow (2.5 ml/min), constituted the total blood flow (10 ml/min) to the liver. Maintenance of intestinal membrane integrity was observed. Rapid ({sup 14}C)glucose absorption against a concentration gradient and a lack of ({sup 3}H)-polyethylene glycol 4000 (PEG 4000, less than 4%) and Evans blue absorption by the recirculating I and IL preparations resulted after bolus injections of these markers into the pyloric end of the duodenum. Other indexes that revealed stable intestinal and liver functions were the following: preservation of reservoir perfusate volume, constancy in perfusion pressure, bile flow, and hemoglobin concentrations, evidence of intestinal glucose utilization and liver glucose production, and a lack of significant leakage of serum glutamic oxalic transaminase. The intestine and liver consumed oxygen at relatively constant rates, but the consumption rates for the fasted tissues (I or L) were significantly higher than those for nonfasted tissues. These results indicate that the vascularly perfused I and IL preparations were maintained in a viable and stable state for a 2-h perfusion period.

  15. An assessment of the probability of double-ended guillotine break in a BWR recirculation piping

    International Nuclear Information System (INIS)

    Menta, H.S.

    1985-01-01

    The requirement for the postulation of a sudden double-ended guillotine break (DEGB) in the high energy piping like the primary coolant piping of nuclear reactors has led to the installation of protective devices such as pipe whip restraints and jet impingement barriers. However, in many cases, these devices, due to their size and location, impede the regular in-service inspection and maintenance. This leads to increased personnel exposure and adverse effects on plant safety and reliability. Therefore, provided it can be shown that the probability of a DEGB is sufficiently low, an improvement in overall plant safety may be achieved by elimination of the DEGB postulation requirement. This paper presents such a probability evaluation for the recirculation piping system of a boiling water reactor (BWR). The DEGB probability was evaluated using a simplified approach based on the methodology developed by Lawrence Livermore Laboratory for PWR primary coolant loop. It is shown that the probability of a DEGB in the example recirculation system is of the order of 10 -10 for the entire 40 year design life

  16. The impact of compaction and leachate recirculation on waste degradation in simulated landfills.

    Science.gov (United States)

    Ko, Jae Hac; Yang, Fan; Xu, Qiyong

    2016-07-01

    This study investigated the impact of compaction and leachate recirculation on anaerobic degradation of municipal solid waste (MSW) at different methane formation phases. Two stainless steel lysimeters, C1 and C2, were constructed by equipping a hydraulic cylinder to apply pressure load (42kPs) on the MSW. When MSW started to produce methane, C1 was compacted, but C2 was compacted when the methane production rate declined from the peak generation rate. Methane production of C1was inhibited by the compaction and resulted in producing a total of 106L methane (44L/kgVS). However, the compaction in C2 promoted MSW degradation resulting in producing a total of 298L methane (125L/kgVS). The concentrations of volatile fatty acids and chemical oxygen demand showed temporary increases, when pressure load was applied. It was considered that the increased substrate accessibility within MSW by compaction could cause either the inhibition or the enhancement of methane production, depending the tolerability of methanogens on the acidic inhibition. Leachate recirculation also gave positive effects on methane generation from wet waste in the decelerated methanogenic phase by increasing mass transfer and the concentrations of volatile fatty acids. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. A numerical model for the dynamic simulation of a recirculation single-effect absorption chiller

    International Nuclear Information System (INIS)

    Zinet, Matthieu; Rulliere, Romuald; Haberschill, Philippe

    2012-01-01

    Highlights: ► Dynamic simulation of a new recirculation single-effect H 2 O/LiBr absorption chiller is developed. ► The chiller is driven by two heat sources and exclusively cooled by the ambient air. ► Heat and mass transfer in the absorber and the desorber are described according to a detailed physical model. ► Analyse of the dynamic behaviour of the chiller after sudden changes in operation. - Abstract: A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller is developed. The chiller is driven by two distinct heat sources, includes a custom integrated falling film evaporator–absorber, uses mixed recirculation and is exclusively cooled by the ambient air. Heat and mass transfer in the evaporator–absorber and in the desorber are described according to a physical model for vapour absorption based on Nusselt’s film theory. The other heat exchangers are handled using a simplified approach based on the NTU-effectiveness method. The model is then used to analyze the chiller response to a step drop of the heat recovery circuit flow rate, and to a sudden reduction of the cooling need in the conditioned space. In the latter case, a basic temperature regulation system is simulated. In both simulations, the performance of the chiller is well represented and consistent with expectations.

  18. Applying rotary jet heads for mixing and mass transfer in a forced recirculation tank reactor system

    DEFF Research Database (Denmark)

    Nordkvist, Mikkel; Grotkjær, Thomas; Hummer, J.S.

    2003-01-01

    An approximation to an ideally mixed tank reactor can be obtained by vigorous stirring with mechanical mixers. For an aerated reactor the gas dispersion contributes to the mixing process. Mixing can also be achieved by recirculation of a portion of the liquid through either an internal or an exte......An approximation to an ideally mixed tank reactor can be obtained by vigorous stirring with mechanical mixers. For an aerated reactor the gas dispersion contributes to the mixing process. Mixing can also be achieved by recirculation of a portion of the liquid through either an internal...... or an external loop.In this study, we determine mixing times in water and CMC solutions and oxygen mass transfer coefficients in water for a tank reactor system where a small fraction of the total liquid volume is rapidly circulated through an external loop and injected through the nozzles of rotary jet heads....... The system has a very simple design with no internal baffles or heat exchange area, and between batches the rotary jet heads are used for cleaning in place.Mixing time decreases and mass transfer increases with increasing circulation flow rate. For nozzle diameters between 5.5 and 10 mm and with one or two...

  19. Determination of oxytetracycline residues in matrixes from a freshwater recirculating aquaculture system.

    Science.gov (United States)

    Carson, Mary C; Bullock, Graham; Bebak-Williams, Julie

    2002-01-01

    This paper describes related procedures to determine the amount of oxytetracycline (OTC) present in trout tissue (muscle with skin attached), biofilter sand, sediment, and tank water from a recirculating aquaculture system. OTC was extracted from the matrixes by different techniques, depending on complexity of the matrix and desired OTC detection level in that matrix. Listed in order of increasing complexity, OTC was extracted from tank water by dilution with acidic buffer containing ethylenediaminetetraacetic acid (EDTA); from biofilter sand by shaking with 0.1 N HCl; from sediment by homogenization and shaking with buffer/EDTA; and from ground trout by homogenization and shaking with buffer/EDTA (twice), with further cleanup and concentration of the extract on a polymeric solid-phase extraction cartridge. The 4 procedures all used the same reversed-phase gradient chromatography on a polymeric column with UV detection at 350 nm. The lower limit of detection (estimated) and upper limit of validation for each of these 4 matrixes were 0.04-4.0 microg/g (ppm; trout), 0.03-20 ppm (biofilter sand), 1-6000 ppm (sediment), and 0.003-10 ppm (water). Recoveries ranged from 82 to 108%, with relative standard deviation <20% over the applicable concentration ranges. These procedures were used to monitor OTC residues resulting from medicated feed administered to rainbow trout in a recirculating aquaculture system.

  20. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2015-09-01

    Full Text Available This paper focuses on assessment of the effect of flue gas recirculation (FGR on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  1. Effects of Exhaust Gas Recirculation on SI Engines at Wide Open Throttle

    Science.gov (United States)

    Bronson, Sydney; Puzinauskas, Paulius

    2011-11-01

    Exhaust gas recirculation, a charge dilution technique, has proven to be an effective method of reducing NOx emissions and fuel consumption of spark ignition engines. Wide open throttle operation also increases overall engine efficiency by reducing the pumping losses caused by throttling. In this study, the emissions and fuel economy benefits of exhaust gas recirculation (EGR) at wide open throttle conditions were quantified using a 2.4L port-injected engine. Engine performance and emissions data were recorded as the percentage of EGR in the intake charge was increased from zero to just above thirty percent (the EGR limit). This EGR percentage, in-cylinder pressure measurements, and the temperatures and pressures of the intake and exhaust were all recorded to ensure stable operating conditions. These tests were performed with a stoichiometric air-fuel ratio at a constant speed of 2000 rpm at wide open throttle. The variation of brake specific fuel consumption and emissions (in particular NOx) with increasing EGR percentages was analyzed.

  2. Production of Spirulina biomass in closed photobioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Torzillo, G.; Pushparaj, B.; Bocci, F.; Balloni, W.; Materassi, R.; Florenzano, G.

    1986-01-01

    The results of six years investigation on the outdoor mass culture of Spirulina platensis and S. maxima in closed tubular photobioreactors are reported. On average, under the climatic conditions of central Italy, the annual yield of biomass obtained from the closed culture units was equivalent to 33 t dry weight/ha per year. In the same climatic conditions the yield of the same organisms grown in open ponds was about 18 t/ha per year. This considerable difference is due primarily to better temperature conditions in the closed culture system. The main problems encountered relate to the control of temperature and oxygen concentration in the culture suspension. This will require an appropriate design and management of the photobioreactor as well as the selection of strains specifically adapted to grow at high temperature and high oxygen concentration. 8 references.

  3. Growth of juvenile Atlantic cod Gadus morhua in land-based recirculation systems: Effects of feeding regime, photoperiod and diet

    DEFF Research Database (Denmark)

    Fülberth, Michael; Moran, Damian; Jarlbæk, Henrik

    2009-01-01

    feeding duration. In each RAS unit three diets (A, B and C) were tested, which were broadly similar in composition but from different manufacturers. Water exchange rate averaged 10–19% in the three recirculation systems, and key water quality parameters such as NH4+ and CO2 remained at low effect......The combined effect of feeding regime and photoperiod on the growth of juvenile Atlantic cod Gadus morhua in land-based recirculating aquaculture systems (RAS) was examined using three different commercial diets. Fish of 8–10 g were reared in 1 m3 tanks at an initial density of 10 kg m− 3 for 78 d...

  4. Recirculation of FNPP1-derived radiocaesium observed in winter 2015/2016 in coastal regions of Japan.

    Science.gov (United States)

    Aoyama, Michio; Hamajima, Yasunori; Inomata, Yayoi; Oka, Eitarou

    2017-08-01

    We conducted enhanced surface water sampling at more than 80 stations in coastal regions on both the Japan Sea and Pacific Ocean sides of Japan in winter 2015/2016 to examine the recirculation behaviour of FNPP1-derived radiocaesium in the surface layer 5 years after the 2011 FNPP1 accident. We found that a small part of the FNPP1-derived radiocaesium had already recirculated in the surface layer and reached the Japanese coast. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Impact of water boundary layer diffusion on the nitrification rate of submerged biofilter elements from a recirculating aquaculture system

    DEFF Research Database (Denmark)

    Prehn, Jonas; Waul, Christopher Kevin; Pedersen, Lars-Flemming

    2012-01-01

    Total ammonia nitrogen (TAN) removal by microbial nitrification is an essential process in recirculating aquaculture systems (RAS). In order to protect the aquatic environment and fish health, it is important to be able to predict the nitrification rates in RAS’s. The aim of this study was to det......Total ammonia nitrogen (TAN) removal by microbial nitrification is an essential process in recirculating aquaculture systems (RAS). In order to protect the aquatic environment and fish health, it is important to be able to predict the nitrification rates in RAS’s. The aim of this study...

  6. Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System.

    Science.gov (United States)

    Peters, Thomas M; Sawvel, Russell A; Park, Jae Hong; Anthony, T Renée

    2015-01-01

    General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a

  7. Utilization of lava stones as water treatment media for the culture of ...

    African Journals Online (AJOL)

    The performance of lava stones as water treatment media in the culture of African catfish (Clarias gariepinus) was investigated. Catfish fingerlings of mean weight 4.7g were stocked in replicates at 32 kg/m3 and reared for 35 days in a recirculating aquaculture system (RAS) facilities with lava stones as biofilter media.

  8. Close to the Sky

    Science.gov (United States)

    2007-11-01

    Today, a new ALMA outreach and educational book was publicly presented to city officials of San Pedro de Atacama in Chile, as part of the celebrations of the anniversary of the Andean village. ESO PR Photo 50a/07 ESO PR Photo 50a/07 A Useful Tool for Schools Entitled "Close to the sky: Biological heritage in the ALMA area", and edited in English and Spanish by ESO in Chile, the book collects unique on-site observations of the flora and fauna of the ALMA region performed by experts commissioned to investigate it and to provide key initiatives to protect it. "I thank the ALMA project for providing us a book that will surely be a good support for the education of children and youngsters of San Pedro de Atacama. Thanks to this publication, we expect our rich flora and fauna to be better known. I invite teachers and students to take advantage of this educational resource, which will be available in our schools", commented Ms. Sandra Berna, the Mayor of San Pedro de Atacama, who was given the book by representatives of the ALMA global collaboration project. Copies of the book 'Close to the sky' will be donated to all schools in the area, as a contribution to the education of students and young people in northern Chile. "From the very beginning of the project, ALMA construction has had a firm commitment to environment and local culture, protecting unique flora and fauna species and preserving old estancias belonging to the Likan Antai culture," said Jacques Lassalle, who represented ALMA at the hand-over. "Animals like the llama, the fox or the condor do not only live in the region where ALMA is now being built, but they are also key elements of the ancient Andean constellations. In this sense they are part of the same sky that will be explored by ALMA in the near future." ESO PR Photo 50c/07 ESO PR Photo 50c/07 Presentation of the ALMA book The ALMA Project is a giant, international observatory currently under construction on the high-altitude Chajnantor site in Chile

  9. Cultivar of Gerbera grown in soil less culture on inert substrates with open and closed systems in comparison with a traditional cultivation on soil in beds; Coltivazione di gerbera in idroponica su substrato con sistema di irrigazione a ciclo aperto e a ciclo chiuso a confronto con la coltivazione tradizionale in cassone su terriccio

    Energy Technology Data Exchange (ETDEWEB)

    Schiavi, A. [MIRAAF, Istituto Sperimentale per l`Orticultura (Italy). Sezione di Ascoli Piceno; Venezia, A. [Istituto Sperimentale per l`Orticoltura (Italy). Sezione di Montanaso Lomabardo; Martignon, G. [Centro Ricerca Ambiente e Materiali, Unita` Calore residuo e Biomasse, Gruppo Agritermia, Milan (Italy)

    1996-01-01

    The aim of the experiment was the evaluation of the yield of several cultivar of gerbera grown in soil less culture on inert substrates with open and closed systems, in comparison with a traditional cultivation on soil in beds. The trial was carried out in the experimental station at Tavazzano (Milan), in a iron plastic greenhouse heated with the waste water discharged by the local thermo electrical power plant. Two inert substrates (rokwool and perlite) were tested in soil less culture both with an open system and a closed system, based on the reuse of the drained nutrient solution. The cultivars Rosula, Pascal, Queen Rebecca, Horizon, Sunspot e Fleur were utilized, grown with a plant density of 10 plants/mq. The trial started in april 1993 and ended in december 1994. The results have pointed out statistically significative differences in the production of cut flower in the growing systems tested. Plants grown in soil less culture with open system gave a number of cut flowers/plant higher both than those grown on soil and with soil less closed system. Agriperlite gave a better commercially yield than rockwool in soil less culture. The distribution of commercial cut flowers in the three category considered (extra, first and second class) was the same for the all thesis; the not marketable production was lower for plant grown on soil than on both the soil less culture systems. With regard to the response of the cultivar, Queen Rebecca and Pascal gave a commercial yield of about 30 cut flowers/plant higher than Rosula, Horizon and Fleur; the cultivar SunSpot showed the lower yield (17 cut flowers/plant).

  10. Influence of recirculation in a lab-scale vertical flow constructed wetland on the treatment efficiency of landfill leachate.

    Science.gov (United States)

    Lavrova, Silviya; Koumanova, Bogdana

    2010-03-01

    Landfill leachate taken from a landfill situated in the north-western region of Bulgaria has been treated in a laboratory scale vertical flow constructed wetland (VF-CW) at different flow rates (40, 60 and 82 ml min(-1)) and recirculation ratios (time of water running through wetland to time of quiet water - 1:1; 1:2; 1:3). Young Phragmites australis was planted on the top layer of the reactor. The low flow rate (40 ml min(-1)) and recirculation ratio of 1:3 allowed removal efficiencies of 96% for COD (in 8 days), 92% for BOD(5) (in 3 days), 100% for ammonia (in 5 days) and 100% for total phosphorus (in 2 days). At the highest flow rate studied (82 ml min(-1)) and shorter quiet period (recirculation ratio 1:1) the water needs longer period of treatment (2 days more according to COD). The results of this study indicate that both flow rate and recirculation ratio should be taken into account for proper design of VF-CW. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  11. Performance of a Water Recirculation Loop Maintenance Device and Process for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Steele, John W.; Rector, Tony; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2013-01-01

    A dual-bed device to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been designed and is undergoing testing. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the development of a water recirculation maintenance device is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The bed design further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  12. Design and Evaluation of a Water Recirculation Loop Maintenance Device for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Steele, John W.; Rector, Tony; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2012-01-01

    A dual-bed device to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been designed and is undergoing testing. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing sublimator technology. The driver for the development of a water recirculation maintenance device is to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high-capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit Transport Water Loop. The bed design further leverages a sorbent developed for the ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System. The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of crewed spaceflight Environmental Control and Life Support System hardware.

  13. A study of NO{sub x} reduction by fuel injection recirculation. Topical report, June--December, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Turns, S.R.; Feese, J.J.

    1996-01-01

    Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO{sub x}) in industrial burner applications. Recent small- and large-scale experiments have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO{sub x}, per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. The objective of this research is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO{sub x} reduction observed between FIR and FGR. This knowledge will aid in the rational application and optimization of FIR in a wide variety of industrial applications. A combined modeling and experimental program is in progress to achieve the research objectives. This report discusses, first, computer modeling studies of counterflow diffusion flames employing detailed chemical kinetics for methane combustion and NO{sub x} formation, and, second, experimental studies of laminar, CH{sub 4}-air, jet flames.

  14. The effect of sludge recirculation rate on a UASB-digester treating domestic sewage at 15 °C

    NARCIS (Netherlands)

    Zhang, L.; Hendrickx, T.L.G.; Kampman, C.; Zeeman, G.; Temmink, B.G.; Weiguang Li,; Buisman, C.J.N.

    2012-01-01

    The anaerobic treatment of low strength domestic sewage at low temperature is an attractive and important topic at present. The upflow anaerobic sludge bed (UASB)-digester system is one of the anaerobic systems to challenge low temperature and concentrations. The effect of sludge recirculation rate

  15. Effect of inoculum addition modes and leachate recirculation on anaerobic digestion of solid cattle manure in an accumulation system

    NARCIS (Netherlands)

    El-Mashad, H.M.; Loon, van W.K.P.; Zeeman, G.; Bot, G.P.A.; Lettinga, G.

    2006-01-01

    The effect of both leachate recirculation (at 40 and 50 °C) and the mode of inoculum addition (at 50 °C) on the performance of a non-mixed accumulation (i.e. fed batch) system treating solid cattle wastes was investigated, using laboratory scale reactors at a filling time of 60 days. A relatively

  16. Design and Evaluation of a Water Recirculation Loop Maintenance Device for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Steele, John W.; Rector, Tony; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2011-01-01

    A dual-bed device to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been designed and is undergoing testing. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the development of a water recirculation maintenance device is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The bed design further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a clear demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  17. Preliminary design study of pebble bed reactor HTR-PM base using once-through-then-out fuel recirculation

    International Nuclear Information System (INIS)

    Topan Setiadipura; Jupiter S Pane; Zuhair

    2016-01-01

    Pebble Bed Reactor (PBR) is one of the advanced reactor type implementing strong passive safety feature. In this type of design has the potential to do a cogeneration useful for the treatment of various minerals in various islands in Indonesia. The operation of the PBR can be simplified by implementing once-through-then-out (OTTO) fuel recirculation scheme in which pebble fuel only pass the core once time. The purpose of this research is to understand quantitative influence of the changing of fuel element recirculation on the PBR core performance and to find preliminary optimization design of PBR type reactor with OTTO recirculation scheme. PEBBED software was used to find PBR equilibrium core. The calculation result gives quantitative data on the impact of implementing a different fuel recirculation, especially using OTTO scheme. Furthermore, an early optimized PBR design based on HTR-PM using OTTO scheme was obtained where the power must be downgraded into 115 MWt in order to preserve the safety feature. The simplicity of the reactor operation and the reduction of reactor component with OTTO scheme still make this early optimized design an interesting alternative design, despite its power reduction from the reference design. (author)

  18. Performance of a Water Recirculation Loop Maintenance Device and Process for the Advanced Spacesuit Water Membrane Evaporator

    Science.gov (United States)

    Rector, Tony; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

    2012-01-01

    A water loop maintenance device and process to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop has been undergoing a performance evaluation. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the water recirculation maintenance device and process is to further enhance this advantage through the leveraging of fluid loop management lessons-learned from the International Space Station (ISS). A bed design that was developed for a Hamilton Sundstrand military application, and considered for a potential ISS application with the Urine Processor Assembly, provides a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance process further leverages a sorbent developed for ISS that introduces a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware. This

  19. Experience With Molecular Adsorbent Recirculating System Treatment in 20 Children Listed for High-Urgency Liver Transplantation

    NARCIS (Netherlands)

    Lexmond, Willem S.; Van Dael, Carin M. L.; Scheenstra, Rene; Goorhuis, Joanne F.; Sieders, Egbert; Verkade, Henkjan J.; Van Rheenen, Patrick F.; Komhoff, Martin

    For more than 10 years, children at our national center for pediatric liver transplantation (LT) have been treated with Molecular Adsorbent Recirculating System (MARS) liver dialysis as a bridging therapy to high-urgency LT. Treatment was reserved for 20 patients with the highest degrees of hepatic

  20. Cortisol and testosterone accumulation in a low pH recirculating aquaculture system for rainbow trout (Oncorhynchus mykiss)

    NARCIS (Netherlands)

    Mota, Vasco C.; Martins, Catarina I.M.; Eding, Ep H.; Canário, Adelino V.M.; Verreth, Johan A.J.

    2017-01-01

    Steroids accumulate in recirculating aquaculture system (RAS), although explanatory factors for such accumulation are still poorly explored. This study investigated the effect of water exchange rate and pH in six replicated RAS on the concentration of the stress hormone cortisol in rainbow trout

  1. Implementation of multiple measures to improve reactor recirculation pump sealing performance in nuclear boiling water reactor service

    Energy Technology Data Exchange (ETDEWEB)

    Loenhout, Gerard van [Flowserve B.V., Etten-Leur (Netherlands). Nuclear Services and Solutions Engineering; Hurni, Juerg

    2015-05-15

    A modern reactor recirculation pump circulates a large volume of high temperature, very pure water from the reactor pressure vessel back to the core by feeding into multiple stationary jet pumps inside the vessel. Together with the jet pumps, they allow station operators to vary coolant flow and variable pump speed provides the best and most stable reactor power control. A crucial technical problem with a recirculation pump, such as a mechanical seal indicating loss of sealing pressure, may result in a power station having to shut down for repair. This article describes the sudden increase in stray current phenomenon leading to rapid and severe deterioration of the mechanical end face shaft seal in a reactor recirculation pump. This occurred after the installation of a variable frequency converter replacing the original motor-generator set. This article will also discuss the 2,500 hour laboratory test results conducted under reactor recirculation pump sealing conditions using a newly developed seal face technology recently implemented to overcome challenges when sealing neutral, ultra-pure water. In addition, the article will describe the elaborate shaft grounding arrangement and the preliminary measurement results achieved in order to eliminate potential damages to both pump and mechanical seal.

  2. Demonstration of Cascaded In-Line Single-Pump Fiber Optical Parametric Amplifiers in Recirculating Loop Transmission

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Ozolins, Oskars; An, Yi

    2012-01-01

    The performance of cascaded single-pump fiber optical parametric amplifiers (FOPAs) is experimentally studied for the first time using recirculating loop transmission with 80-km dispersion managed spans. Error-free performance has been achieved over 320 km for 40-Gbit/s CSRZ-OOK and CSRZ...

  3. The effects of ozonation on select waterborne steroid hormones in recirculation aquaculture systems containing sexually mature Atlantic salmon Salmo salar

    Science.gov (United States)

    A controlled 3-month study was conducted in 6 replicated water recirculation aquaculture systems (RAS) containing a mixture of sexually mature and immature Atlantic salmon Salmo salar to determine whether water ozonation is associated with a reduction in waterborne hormones. Post-smolt Atlantic salm...

  4. The impact of water exchange rate on the health and performance of rainbow trout Oncorhynchus mykiss in recirculation aquaculture systems

    Science.gov (United States)

    Fish mortality in recirculating aquaculture systems (RAS) has been observed by the authors to increase when RAS are managed at low makeup water exchange rates with relatively high feed loading. The precise etiology of this elevated mortality was unknown, all typical water quality parameters were wit...

  5. The effects of carbon dioxide on performance and histopathology of rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Science.gov (United States)

    Chronic exposure to elevated levels of dissolved carbon dioxide (CO2) has been linked to reduced growth, physiological disturbances and negative health outcomes in intensively reared fish. Although pumping to a degassing tower can lower concentrations of dissolved CO2 in water recirculation aquacult...

  6. Parametric Effects of Debris Source, Environments, and Design Options on the Overall Performance of ECCS Recirculation Sump

    International Nuclear Information System (INIS)

    Park, Jong Woon; Kim, Chang Hyun

    2006-01-01

    A primary safety issue regarding long-term recirculation core cooling following a LOCA (Loss of Coolant Accident) is that LOCA-generated debris may be transported to the recirculation sump screen, resulting in adverse blockage on the sump screen and deterioration of available NPSH (Net Positive Suction Head) of ECCS (Emergency Core Cooling System). USNRC identified this as Generic Safety Issue (GSI) 191 and issued the Generic Letter 04-02 to resolve the issue. The GL required that all PWR owners perform an engineering assessment of their containment recirculation sumps to ensure they will not suffer from excessive blockage. The guidance report (GR) for PWR sump performance evaluation has been developed by NEI (Nuclear Energy Institute) and approved by the USNRC. In Korea, Korea Hydro and Nuclear Power Company (KHNP) is performing the assessment of Kori unit 1 and planning for remaining plants in the near future. The objective of the assessment is to derive required plant modifications including insulation, sump screen, etc. To derive the cost-effective modification items, we have to get insight on the parametric effects of plant conditions and design. Therefore, the general effects of debris source, containment environments and debris interceptor on the performance of ECCS recirculation sump with respect to head loss are parametrically investigated

  7. Three dimensional computational fluid dynamic analysis of debris transport under emergency cooling water recirculation

    International Nuclear Information System (INIS)

    Park, Jong Woon

    2010-01-01

    This paper provides a computational fluid dynamic (CFD) analysis method on the evaluation of debris transport under emergency recirculation mode after loss of coolant accident of a nuclear power plant. Three dimensional reactor building floor geometrical model is constructed including flow obstacles larger than 6 inches such as mechanical components and equipments and considering various inlet flow paths from the upper reactor building such as break and spray flow. In the modeling of the inlet flows from the upper floors, effect of gravitational force was also reflected. For the precision of the analysis, 3 millions of tetrahedral-shaped meshes were generated. Reference calculation showed physically reasonable results. Sensitivity studies for mesh type and turbulence model showed very similar results to the reference case. This study provides useful information on the application of CFD to the evaluation of debris transport fraction for the design of new emergency sump filters. (orig.)

  8. Parameter choices for a muon recirculating linear accelerator from 5 to 63 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J. S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-06-19

    A recirculating linear accelerator (RLA) has been proposed to accelerate muons from 5 to 63 GeV for a muon collider. It should be usable both for a Higgs factory and as a stage for a higher energy collider. First, the constraints due to the beam loading are computed. Next, an expression for the longitudinal emittance growth to lowest order in the longitudinal emittance is worked out. After finding the longitudinal expression, a simplified model that describes the arcs and their approximate expression for the time of flight dependence on energy in those arcs is found. Finally, these results are used to estimate the parameters required for the RLA arcs and the linac phase.

  9. Control-Oriented Model of Molar Scavenge Oxygen Fraction for Exhaust Recirculation in Large Diesel Engines

    DEFF Research Database (Denmark)

    Nielsen, Kræn Vodder; Blanke, Mogens; Eriksson, Lars

    2016-01-01

    therefore focus on deriving and validating a mean-value model of a large two-stroke crosshead diesel engines with EGR. The model introduces a number of amendments and extensions to previous, complex models and shows in theory and practice that a simplified nonlinear model captures all essential dynamics...... the behavior of the scavenge oxygen fraction well over the entire envelope of load and blower speed range that are relevant for EGR. The simplicity of the new model makes it suitable for observer and control design, which are essential steps to meet the emission requirements for marine diesel engines that take......Exhaust gas recirculation (EGR) systems have been introduced to large marine engines in order to reduce NOx formation. Adequate modelling for control design is one of the bottlenecks to design EGR control that also meets emission requirements during transient loading conditions. This paper...

  10. Post-accident recirculation filters for fission product removal from the containment atmosphere

    International Nuclear Information System (INIS)

    Dillmann, H.G.; Pasler, H.

    1975-01-01

    The prototype post-accident recirculation filters have been subjected to further tests made under various conditions. The filter system exposed to hot air of 160 0 C and to saturated steam up to 1 atm and temperatures between 108 0 C and 160 0 C yielded for residence times of 0.2 sec after 18 days of permanent operation removal efficiencies > 99.98% for CH 3 J with a flow of 1,200 m 3 /h. Induced by previous experimental results the adsorber material was examined for transportation of the impregnation by the air-steam mixture. No measurable transportation was found (detection limit 0.6 x 10 -6 g Ag when 32 g of sorption material were used) under different conditions up to temperatures of 200 0 C in superheated steam over a duration of the experiment of 48 h. (orig.) [de

  11. Influence of fixed and moving bed biofilters on micro particle dynamics in a recirculating aquaculture system

    DEFF Research Database (Denmark)

    Fernandes, Paulo; Pedersen, Lars-Flemming; Pedersen, Per Bovbjerg

    2017-01-01

    Accumulation of fine particulate organic matter in recirculating aquaculture systems (RAS) is a balancebetween system input (from feed to waste), internal transformation, removal and dilution. The mecha-nisms leading to fine particle accumulation in RAS are not fully understood, and neither...... (Oncorhynchus mykiss), and operatedunder constant feed loading conditions (1 kg feed/m3of make-up water) for more than three months.Production or removal of micro particles according to biofilter mode of operation (FBB vs. MBB) wasassessed by operating all biofilters simultaneously as well as separately....... Nitrate levels ranged between 40and 44 mg N/L, reflecting stable operating conditions and constant feed loading.The trends observed when FBB or MBB were operated separately were also observed when all filterswere operated simultaneously. Differences in biofilm formation, development and maintenance...

  12. Effects of feed loading on nitrogen balances and fish performance in replicated recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Lars-Flemming; Suhr, Karin Isabel; Dalsgaard, Anne Johanne Tang

    2012-01-01

    This study investigated the effects of applying four fixed feed loadings to three replicated recirculating aquaculture systems (RAS) on water quality changes, nitrogenous balances and growth performance of rainbow trout (Oncorhynchus mykiss).Feed loadings ranged from 1.6 to 6.3kgfeed/m3 make...... nitrification performance and diurnal patterns of total ammonia nitrogen (TAN) and nitrite concentrations. No fish mortality occurred during the study. Feed conversion ratios varied between 0.91±0.04 and 0.95±0.02, and were unaffected by feeding load. Mean nitrate-nitrogen levels ranged from 54±7 to 196±10mg....../L at steady state, and the concentration of nitrogenous compounds and organic matter were all positively correlated to feed loading.The TAN loading to the RAS from the specific feed type was assessed in a separate mass-balance study and used as input in a descriptive mathematical model (AQUASIM® software...

  13. Acceleration ion focusing (IFR) and transport experiments with the recirculating linear accelerator (RLA)

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Smith, D.L.; Puokey, J.W.; Bennett, L.F.; Wagner, J.S.; Olson, W.R.; George, M.; Turman, B.N.; Prestwich, K.R.; Struve, K.W.

    1992-01-01

    The focusing and transport of intense relativistic electron beams in the Sandia Laboratories Recirculating Linear Accelerator (RLA) is accomplished with the aid of an ion focusing channel (IFR). We report here experiments evaluating the beam generation in the injector and its subsequent acceleration and transport through the first post-accelerating cavity. Two injectors and one type of post-accelerating cavity were studied. Beams of 6-20 kA current were injected and successfully transported and accelerated through the cavity. The transport efficiencies were 90% - 100%, and the beam Gaussian profile (4 MeV injector) and radius (5 mm) remained the same through acceleration. We describe the RLA, present the experimental results and compare them with numerical simulations. (Author) 3 refs., 7 figs

  14. Analysis of the sodium recirculation theory of solute-coupled water transport in small intestine

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkaer

    2002-01-01

    Our previous mathematical model of solute-coupled water transport through the intestinal epithelium is extended for dealing with electrolytes rather than electroneutral solutes. A 3Na+-2K+ pump in the lateral membranes provides the energy-requiring step for driving transjunctional and translateral...... permeabilities and pump constants of fluxes of water and electrolytes, volumes and ion concentrations of cell and lateral intercellular space (lis), and membrane potentials and conductances. Simulating physiological bioelectrical features together with cellular and paracellular fluxes of the sodium ion......, computations predict that the concentration differences between lis and bathing solutions are small for all three ions. Nevertheless, the diffusion fluxes of the ions out of lis significantly exceed their mass transports. It is concluded that isotonic transport requires recirculation of all three ions...

  15. A re-circulated toxicity exposure chamber to evaluate hydrocarbon dispersions

    International Nuclear Information System (INIS)

    Fuller, C.B.; Bonner, J.S.; Bujnoch, J.D.; Ussery, S.F.; Arrambide, G.; Sterling, M.C.

    2002-01-01

    Traditional toxicology methods are not suitable for evaluating chemically dispersed oil which exists mostly as a colloidal suspension and as dissolved fractions. A new toxicity exposure chamber was designed with separate chambers for scaled mixing and organism exposure. The design of the chamber incorporates continuous recirculation between the mixing and exposure chamber and an upward flow in the exposure chamber. The toxicity exposure system incorporates scalable and quantitative mixing inputs with real time particle size analysis and traditional petrochemistry methods to characterize the exposure regime. Changes in dispersion were successfully translated to the organism exposure regime. The study determined the petroleum toxicity with a juvenile marine test species. Low control mortality demonstrated the usefulness of the method for testing toxicity of colloidal oil suspensions. 20 refs., 1 tab., 4 figs

  16. Diesel engine exhaust gas recirculation--a review on advanced and novel concepts

    International Nuclear Information System (INIS)

    Zheng Ming; Reader, Graham T.; Hawley, J. Gary

    2004-01-01

    Exhaust gas recirculation (EGR) is effective to reduce nitrogen oxides (NO x ) from Diesel engines because it lowers the flame temperature and the oxygen concentration of the working fluid in the combustion chamber. However, as NO x reduces, particulate matter (PM) increases, resulting from the lowered oxygen concentration. When EGR further increases, the engine operation reaches zones with higher instabilities, increased carbonaceous emissions and even power losses. In this research, the paths and limits to reduce NO x emissions from Diesel engines are briefly reviewed, and the inevitable uses of EGR are highlighted. The impact of EGR on Diesel operations is analyzed and a variety of ways to implement EGR are outlined. Thereafter, new concepts regarding EGR stream treatment and EGR hydrogen reforming are proposed

  17. Development of fluorocarbon evaporative cooling recirculators and controls for the ATLAS inner silicon tracker

    CERN Document Server

    Bayer, C; Bonneau, P; Bosteels, Michel; Burckhart, H J; Cragg, D; English, R; Hallewell, G D; Hallgren, Björn I; Ilie, S; Kersten, S; Kind, P; Langedrag, K; Lindsay, S; Merkel, M; Stapnes, Steinar; Thadome, J; Vacek, V

    2000-01-01

    We report on the development of evaporative fluorocarbon cooling recirculators and their control systems for the ATLAS inner silicon tracker. We have developed a prototype circulator using a dry, hermetic compressor with C/sub 3/F/sup 8/ refrigerant, and have prototyped the remote-control analog pneumatic links for the regulation of coolant mass flows and operating temperatures that will be necessary in the magnetic field and radiation environment around ATLAS. pressure and flow measurement and control use 150+ channels of standard ATLAS LMB ("Local Monitor Board") DAQ and DACs on a multi-drop CAN network administered through a BridgeVIEW user interface. A hardwired thermal interlock system has been developed to cut power to individual silicon modules should their temperatures exceed safe values. Highly satisfactory performance of the circulator under steady state, partial-load and transient conditions was seen, with proportional fluid flow tuned to varying circuit power. Future developments, including a 6 kW...

  18. Reliability analysis of the recirculation phase of the safety injection system of Angra-1

    International Nuclear Information System (INIS)

    Rivera, R.R.J.M.

    1981-09-01

    The calculation of several reliability parameters-failure probability, unavailability and unreliability - of the recirculation phase of the safety injection system of Angra-1, was done. This system has two distinct modes of operation (short term and long term) which were fault tree analysed both separately and as a whole. To obtain quantitative results the computer codes SAMPLE and PRET-KITT were utilized. The former was used to consider the uncertainties in the failure data (drawn integrally from WASH-1400) and the latter to obtain time dependent unreliability values. Hardware failures and common-mode failures were considered. Altough the analysis methods employed here differ somewhat from those used in WASH-1400, the results which could be compared were found to have the order of magnitude. A viability study of some suggestions of system's modifications was performed, and it has shown that some significant reliability improvements can be achieved with reasonably simple changes. (Author) [pt

  19. Categorization of flow conditions using Integral quantities for characterizing stagnation and recirculation

    International Nuclear Information System (INIS)

    Han, M.H.; Hwang, W.T.; Jeong, H.J.; Kim, E.H.

    2008-01-01

    This paper describes a method for categorizing an atmospheric flow condition of a site by using integral quantities for characterizing stagnation and recirculation. Authors have devised a method for categorizing flow conditions using distribution curves which represent the flow condition of the whole of Korea. It was found that the flow conditions for four nuclear power plant sites were good enough from a meteorological aspect. Among the four sites, Kori nuclear power plant site which is located at the south-eastern part of the Korean peninsular shows the best condition. Meteorological condition is the key factor for estimating the environmental effects of a nuclear facility. The devised method can be used for assessing the relative environmental risk of a nuclear facility with only meteorological data. And the devised categorization method can be used for choosing a suitable site for an industrial facility such as a nuclear power plant and a chemical complex. (author)

  20. The effects of leachate recirculation with supplemental water addition on methane production and waste decomposition in a simulated tropical landfill.

    Science.gov (United States)

    Sanphoti, N; Towprayoon, S; Chaiprasert, P; Nopharatana, A

    2006-10-01

    In order to increase methane production efficiency, leachate recirculation is applied in landfills to increase moisture content and circulate organic matter back into the landfill cell. In the case of tropical landfills, where high temperature and evaporation occurs, leachate recirculation may not be enough to maintain the moisture content, therefore supplemental water addition into the cell is an option that could help stabilize moisture levels as well as stimulate biological activity. The objectives of this study were to determine the effects of leachate recirculation and supplemental water addition on municipal solid waste decomposition and methane production in three anaerobic digestion reactors. Anaerobic digestion with leachate recirculation and supplemental water addition showed the highest performance in terms of cumulative methane production and the stabilization period time required. It produced an accumulated methane production of 54.87 l/kg dry weight of MSW at an average rate of 0.58 l/kg dry weight/d and reached the stabilization phase on day 180. The leachate recirculation reactor provided 17.04 l/kg dry weight at a rate of 0.14l/kg dry weight/d and reached the stabilization phase on day 290. The control reactor provided 9.02 l/kg dry weight at a rate of 0.10 l/kg dry weight/d, and reached the stabilization phase on day 270. Increasing the organic loading rate (OLR) after the waste had reached the stabilization phase made it possible to increase the methane content of the gas, the methane production rate, and the COD removal. Comparison of the reactors' efficiencies at maximum OLR (5 kgCOD/m(3)/d) in terms of the methane production rate showed that the reactor using leachate recirculation with supplemental water addition still gave the highest performance (1.56 l/kg dry weight/d), whereas the leachate recirculation reactor and the control reactor provided 0.69 l/kg dry weight/d and 0.43 l/kg dry weight/d, respectively. However, when considering

  1. FROZEN ASH BERRIES PROCESSING IN THE DEVICE WITH A NOZZLE CONTINUOUS VIBRATION, EQUIPPED WITH AN EXTERNAL RECIRCULATION LOOP

    Directory of Open Access Journals (Sweden)

    P. P. Ivanov

    2015-01-01

    Full Text Available An external recirculation loop was used as the method of increasing the concentration of dry soluble substances in the obtained extract. The objective of the research is to determine the value of the external recirculation index (KR, which provides the optimal conditions for the process carrying out. The results of the conducted research show the increase in the concentration of dry soluble substances in the extract if the external recirculation index increases. It is conditioned by the extension of the interaction between the processed raw mate-rial and the extract, as well as by the decrease in the surface tension of the extracting agent, which results in improving the conditions of its penetration into the pores of particles. Such an opposite property of recirculation as the decrease in mass transfer rate was also ob-served. It causes the significant rise of dry soluble substances losses while discharging extraction cake, which leads to the performance degradation. According to the analytical evaluation of the obtained results, the maximum process results are observed if KR = 1 (without recirculation and KR = 2, the values of the optimality criterion are 5.02∙10-3 and 4.92∙10-3 % mass/W respectively. At the same time the operation of the apparatus with the recirculation loop at KR = 2 is characterized by 62%-increase in dry soluble substances concentration in the extract as compared to a pure extracting agent. The efficiency of recirculation at KR = 2 is proved by the saving of energy con-sumed on the evaporation of the extract obtained. The energy costs calculation for the production of 60l of 12 % mass dry soluble sub-stances concentration extract showed that if the initial dry soluble substances concentration is raised to 6 % mass (KR = 2, the amount of consumed saturated vapor is 104.1 kg less, which is 281685 kJ if the vapor specific enthalpy is 2706.29 kJ/kg.

  2. Central recirculation zones and instability waves in internal swirling flows with an annular entry

    Science.gov (United States)

    Wang, Yanxing; Yang, Vigor

    2018-01-01

    The characteristics of the central recirculation zone and the induced instability waves of a swirling flow in a cylindrical chamber with a slip head end have been numerically investigated using the Galerkin finite element method. The effects of Reynolds number as well as swirl level adjusted by the injection angle were examined systematically. The results indicate that at a high swirl level the flow is characterized by an axisymmetric central recirculation zone (CRZ). The fluid in the CRZ takes on a solid-body rotation driven by the outer main flow through a free shear layer. Both the solid-body rotating central flow and the free shear layer provide the potential for the development of instability waves. When the injection angle increases beyond a critical value, the basic axisymmetric flow loses stability, and instability waves develop. In the range of Reynolds numbers considered in this study, three kinds of instability were identified: inertial waves in the central flow, and azimuthal and longitudinal Kelvin-Helmholtz waves in the free shear layer. These three types of waves interact with each other and mix together. The mode selection of the azimuthal waves depends strongly on the injection angle, through the perimeter of the free shear layer. Compared with the injection angle, the Reynolds number plays a minor role in mode selection. The flow topologies and characteristics of different flow states are analyzed in detail, and the dependence of flow states on the injection angle and Reynolds number is summarized. Finally, a linear analysis of azimuthal instabilities is carried out; it confirms the mode selection mechanisms demonstrated by the numerical simulation.

  3. Reaction behavior of SO2 in the sintering process with flue gas recirculation.

    Science.gov (United States)

    Yu, Zhi-Yuan; Fan, Xiao-Hui; Gan, Min; Chen, Xu-Ling; Chen, Qiang; Huang, Yun-Song

    2016-07-01

    The primary goal of this paper is to reveal the reaction behavior of SO2 in the sinter zone, combustion zone, drying-preheating zone, and over-wet zone during flue gas recirculation (FGR) technique. The results showed that SO2 retention in the sinter zone was associated with free-CaO in the form of CaSO3/CaSO4, and the SO2 adsorption reached a maximum under 900ºC. SO2 in the flue gas came almost from the combustion zone. One reaction behavior was the oxidation of sulfur in the sintering mix when the temperature was between 800 and 1000ºC; the other behavior was the decomposition of sulfite/sulfate when the temperature was over 1000ºC. However, the SO2 adsorption in the sintering bed mainly occurred in the drying-preheating zone, adsorbed by CaCO3, Ca(OH)2, and CaO. When the SO2 adsorption reaction in the drying-preheating zone reached equilibrium, the excess SO2 gas continued to migrate to the over-wet zone and was then absorbed by Ca(OH)2 and H2O. The emission rising point of SO2 moved forward in combustion zone, and the concentration of SO2 emissions significantly increased in the case of flue gas recirculation (FGR) technique. Aiming for the reuse of the sensible heat and a reduction in exhaust gas emission, the FGR technique is proposed in the iron ore sintering process. When using the FGR technique, SO2 emission in exhaust gas gets changed. In practice, the application of the FGR technique in a sinter plant should be cooperative with the flue gas desulfurization (FGD) technique. Thus, it is necessary to study the influence of the FGR technique on SO2 emissions because it will directly influence the demand and design of the FGD system.

  4. Low frequency ultrasound and UV-C for elimination of pathogens in recirculating aquaculture systems.

    Science.gov (United States)

    Bazyar Lakeh, Amir Abbas; Kloas, Werner; Jung, Rainer; Ariav, Ra'anan; Knopf, Klaus

    2013-09-01

    Low frequency ultrasound (LFUS) was evaluated as a novel disinfection technique within recirculating aquaculture systems both individually and combined with UV-C. Dose-dependent inactivation rates were determined for the total viable counts and model organisms representing different taxa of common fish parasites: the ciliate Paramecium sp., second larval stage (L2) of the nematode Anguillicola crassus and metanauplii of Artemia sp. Application of LFUS up to 19 kJ/L did not reduce the number of colony forming units (CFU), whilst UV-C irradiation was highly effective. Pre-treatment with LFUS reduced the mean size of suspended solids in aquaculture water and thus increased the germicidal effect of UV-C by up to 0.6 log units. LFUS was effective against the eukaryotic organisms, and the dose-dependent inactivation could be well described by functions of an exponential decay. However, the efficiency of LFUS differed greatly between species. A LFUS dose of 1.9 kJ/L (consumed energy) was sufficient to inactivate Artemia by 99%, but a ten times higher dose was necessary to inactivate 95% and 81% of Paramecium and Anguillicola larvae, respectively. In clear water, the energetic efficiency of UV-C (emitted by a low pressure lamp) against Paramecium and Anguillicola larvae was higher compared to LFUS, but LFUS was more efficient against Artemia. However, the efficiency of LFUS against ciliates or nematode larvae would be similar or even higher than UV-C in highly turbid water or if less efficient medium pressure lamps are used. This study shows that LFUS can be applied safely at energy densities that are effective against a wide range of parasites like ciliates, nematodes and crustaceans. The combination of LFUS and UV-C could provide an appropriate water treatment with regards to all relevant pathogens in recirculating aquaculture systems. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. The effect of precipitation on municipal solid waste decomposition and methane production in simulated landfill bioreactor with leachate recirculation

    Directory of Open Access Journals (Sweden)

    Pawinee Chaiprasert

    2006-05-01

    Full Text Available The objective of this study is to investigate MSW degradation and methane production in a simulated landfill bioreactor with leachate recirculation under conditions with and without water addition at the representative level of annual precipitation. Experiments were carried out in four simulated reactors using 0.3 m diameter PVC pipe of 1.25 m height. Two leachate recirculation reactors were operated with water addition and the other two were operated without water addition. The results showed that leachate recirculation with precipitation led to greater performance in terms of accelerated biological stabilization and the onset of methanogenesis. In the reactors operated with precipitation, the reduction of COD was 24-54 times higher than that in reactors without precipitation. The percentage of waste decomposition was 59.0-61.4% and the methane production rate was 0.479-0.638 l/kg dry waste/day at the stabilization phase in the reactors operated with precipitation. Conversely, 19.6-22.4% of waste decomposition and 0.01 l/kg dry waste of methane production were found in reactors operated without precipitation. In this experiment, the feasibility of introducing moisture only by leachate recirculation, with no precipitation, seemed to be unsuitable for recirculation due to the high concentration of leachate pollutant. A large quantity of buffering chemical was used. Therefore, during the hydrolysis and acidogenesis phases, precipitation or water added was important for the waste decomposition as to dilute and flush out high TVA concentration and create a favorable environment for methanogenesis.

  6. Production of polycaprolactone nanoparticles with low polydispersity index in a tubular recirculating system by using a multifactorial design of experiments

    Science.gov (United States)

    Colmenares Roldán, Gabriel Jaime; Agudelo Gomez, Liliana María; Carlos Cornelio, Jesús Antonio; Rodriguez, Luis Fernando; Pinal, Rodolfo; Hoyos Palacio, Lina Marcela

    2018-03-01

    Encapsulation and controlled release of substances using polymeric nanoparticles require that these have a high reproducibility, homogeneity, and control over their properties (diameter and polydispersity), especially when they are to be used in medical, pharmaceutical, or nutritional applications among others. In conventional production systems, it is tough to ensure these characteristics; hence, the cost increases when we try to control these properties. This paper shows a comparison between a recirculating system and the standard nanoprecipitation technique for producing polymeric nanoparticles. In previous investigations, we evaluate the effect of recirculating flow and the ratio between the organic and aqueous phase. For this paper, we evaluated the effect of polymer and surfactant concentrations using a multifactorial design of experiments on the recirculating system and on the standard nanoprecipitation system. The response of the design was the average diameter of the nanoparticles and polydispersity index. Finally, we found that the polymer and surfactant concentrations could change the average diameter and polydispersity index of the nanoparticles obtained. On the other hand, it was found that the effect of the polymer concentration was stronger than the surfactant concentration to reduce the average diameter of the nanoparticles. The results of the present study show that the proposed recirculation system presents a high potential to produce polymer nanoparticles with good morphological characteristics, particle size distributions in the nano range, and with a low polydispersity. The average mean size of nanoparticles of polycaprolactone for the design using the recirculating system was of 61 to 140 nm and the values of polydispersity index PDI for this design were between 0.097 and 0.22, while for the design using the standard nanoprecipitation technique, the obtained diameters were 74 to 176 nm and the polydispersity was between 0.26 and 0.41.

  7. Modular extracorporeal life support: effects of ultrafiltrate recirculation on the performance of an extracorporeal carbon dioxide removal device.

    Science.gov (United States)

    Scaravilli, Vittorio; Kreyer, Stefan; Linden, Katharina; Belenkiy, Slava; Jordan, Bryan; Pesenti, Antonio; Zanella, Alberto; Chung, Kevin; Cannon, Jeremy; Cancio, Leopoldo C; Batchinsky, Andriy I

    2014-01-01

    The combination of extracorporeal carbon dioxide removal (ECCO2R) and hemofiltration is a possible therapeutic strategy for patients needing both lung and renal support. We tested the effects of the recirculation of ultrafiltrate on membrane lung (ML) CO2 removal (VCO2ML). Three conscious, spontaneously breathing sheep were connected to a commercially produced ECCO2R device (Hemolung; Alung Technologies, Pittsburgh, PA) with a blood flow of 250 ml/min and a gas flow of 10 L/min. A hemofilter (NxStage, NxStage Medical, Lawrence, MA) was interposed in series after the ML. Ultrafiltrate flow was generated and recirculated before the ML. We tested four ultrafiltrate flows (0, 50, 100, and 150 ml/min) for 25 min each, eight times per animal, resulting in 24 randomized test repetitions. We recorded VCO2ML, hemodynamics and ventilatory variables, and natural lung CO2 transfer (VCO2NL) and collected arterial and circuitry blood samples. VCO2ML was unchanged by application of ultrafiltrate recirculation (40.5 ± 4.0, 39.7 ± 4.2, 39.8 ± 4.2, and 39.2 ± 4.1 ml/min, respectively, at ultrafiltrate flow of 0, 50, 100, and 150 ml/min). Minute ventilation, respiratory rate, VCO2NL, and arterial blood analyses were not affected by ultrafiltrate recirculation. In the tested configuration, ultrafiltrate recirculation did not affect VCO2ML. This modular technology may provide a suitable platform for coupling CO2 removal with various forms of blood purification.

  8. Cultural Perspectives Toward Language Learning

    Science.gov (United States)

    Lin, Li-Li

    2008-01-01

    Cultural conflicts may be derived from using inappropriate language. Appropriate linguistic-pragmatic competence may also be produced by providing various and multicultural backgrounds. Culture and language are linked together naturally, unconsciously, and closely in daily social lives. Culture affects language and language affects culture through…

  9. Using mushroom farm and anaerobic digestion wastewaters as supplemental fertilizer sources for growing container nursery stock in a closed system.

    Science.gov (United States)

    Chong, C; Purvis, P; Lumis, G; Holbein, B E; Voroney, R P; Zhou, H; Liu, H-W; Alam, M Z

    2008-04-01

    Wastewaters from farm and composting operations are often rich in select nutrients that potentially can be reutilized in crop production. Liners of silverleaf dogwood (Cornus alba L. 'Argenteo-marginata'), common ninebark [Physocarpus opulifolius (L.) Maxim.], and Anthony Waterer spirea (Spiraeaxbumalda Burvénich 'Anthony Waterer') were grown in 6L containers filled with a bark-based commercial mix. Plants were fertigated daily via a computer-controlled multi-fertilizer injector with three recirculated fertilizer treatments: (1) a stock (control) solution with complete macro- and micro-nutrients, electrical conductivity (EC) 2.2 dS m(-1); (2) wastewater from a mushroom farm; and (3) process wastewater from anaerobic digestion of municipal solid waste. The wastewaters used in both treatments 2 and 3 were diluted with tap water, and the computer was programmed to amend, dispense and recirculate nutrients based on the same target EC as in treatment 1. For comparison, there was a traditional controlled-release fertilizer treatment [Nutryon 17-5-12 (17N-2P-10K) plus micro-nutrients topdressed at a rate of 39 g/plant, nutrients not recirculated]. All three species responded similarly to the three recirculated fertilizer treatments. Growth with the recirculated treatments was similar and significantly higher than that obtained with controlled-release fertilizer. Throughout the study, the EC measured in wastewater-derived nutrient solutions, and also in the container substrate, were similar or close to those of the control treatment, although there were small to large differences among individual major nutrients. There was no sign of nutrient deficiency or toxicity symptoms to the plants. Small to moderate excesses in concentrations of SO(4), Na, and/or Cl were physiologically tolerable to the species.

  10. Environmental control implications of generating electric power from coal. 1977 technology status report. Appendix D. Assessment of NO/sub x/ control technology for coal fired utility boilers. [Low-excess-air, staged combustion, flu gas recirculation and burner design

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    An NOx control technology assessment study was conducted to examine the effectiveness of low-excess-air firing, staged combustion, flue gas recirculation, and current burner/boiler designs as applied to coal-fired utility boilers. Significant variations in NOx emissions exist with boiler type, firing method, and coal type, but a relative comparison of emissions control performance, cost, and operational considerations is presented for each method. The study emphasized the numerous operational factors that are of major importance to the user in selecting and implementing a combustion modification technique. Staged combustion and low-excess-air operation were identified as the most cost-effective methods for existing units. Close control of local air/fuel ratios and rigorous combustion equipment maintenance are essential to the success of both methods. Flue gas recirculation is relatively ineffective and has the added concern of tube erosion. More research is needed to resolve potential corrosion concerns with low-NOx operating modes. Low-NOx burners in conjunction with a compartmentalized windbox are capable of meeting a 0.6-lb/million Btu emission level on new units. Advanced burner designs are being developed to meet research emission goals of approximately 0.25 lb/MBtu.

  11. Close-Ups

    DEFF Research Database (Denmark)

    Fausing, Bent

    2013-01-01

    Investigations in the close-up and its meaning regarding nearness, abstraction and transparency. Face, facelike and animism are also major key-words in thsi article... . I have always been fascinated with the close-up, not as an end, but a filter of opportunities to open up for and nearness...... of transcendence, associations and memories. The close-up is not the end, it rather in my view to be regarded as a beginning of different perceptions...

  12. FROM CULTURAL IMPOTENCE TO CULTURAL AMPUTATION

    Directory of Open Access Journals (Sweden)

    Вячеслав Владимирович Суханов

    2013-04-01

    Full Text Available Cultural space of any state is formed by a population that is within its borders. In this article, the author introduces a new cultural definitions «cultural impotence» and «cultural amputation», justifying their use, both in terms of population of the Russian Federation and the European Union and America. The article analyzes the state of society and the cultural factors that influence the development of society in Russia, there are options to bring the country out of a deep cultural crisis. Also established a close relationship between the domestic policy of the state and development of culture.DOI: http://dx.doi.org/10.12731/2218-7405-2013-2-1

  13. Identifying and training adaptive cross-cultural management skills: The crucial role of cultural metacognition

    NARCIS (Netherlands)

    S. Mor (Shira); M.W. Morris (Michael); J. Joh (Johann)

    2013-01-01

    textabstractFor managers, intercultural effectiveness requires forging close working relationships with people from different cultural backgrounds (Black, Mendenhall, and Oddou, 1991). Recent research with executives has found that higher cultural metacognition is associated with affective closeness

  14. Design, operation, and potential of a culture system for the continuous production of Artemia nauplii

    OpenAIRE

    Lavens, P.; Sorgeloos, P.

    1987-01-01

    A flow-through system is described for the controlled production of Artemia nauplii. High densities of adult brine shrimp are induced to ovoviviparity through diet manipulation, optimal culture water exchange, and high constant oxygen levels. The nauplii produced are separated from the culture tank effluents in a special recuperation filter system. The culture water is recirculated over a rotating biodisc, a cross-flow sieve, and a plate separator.The potential of this nauplii production syst...

  15. Effects of a Dual-Loop Exhaust Gas Recirculation System and Variable Nozzle Turbine Control on the Operating Parameters of an Automotive Diesel Engine

    Directory of Open Access Journals (Sweden)

    Giorgio Zamboni

    2017-01-01

    Full Text Available Reduction of NOX emissions and fuel consumption are the main topics in engine development, forcing the adoption of complex techniques and components, whose interactions have to be clearly understood for proper and reliable operations and management of the whole system. The investigation presented in this paper aimed at the development of integrated control strategies of turbocharging, high pressure (HP and low pressure (LP exhaust gas recirculation (EGR systems for better NOX emissions and fuel consumption, while analyzing their reciprocal influence and the resulting variations of engine quantities. The study was based on an extended experimental program in three part load engine operating conditions. In the paper a comparison of the behavior of the main engine sub-systems (intake and exhaust circuits, turbocharger turbine and compressor, HP and LP EGR loops in a wide range of operating modes is presented and discussed, considering open and closed loop approaches for variable nozzle turbine (VNT control, and showing how these affect engine performance and emissions. The potential of significant decrease in NOX emissions through the integration of HP and LP EGR was confirmed, while a proper VNT management allowed for improved fuel consumption level, if an open loop control scheme is followed. At higher engine speed and load, further actions have to be applied to compensate for observed soot emissions increase.

  16. Comparison of biocides for disinfection treatment of open recirculating cooling circuits

    International Nuclear Information System (INIS)

    Soreau, Sylvie; Prisset, Frederic; Carvajal, Nathalie

    2012-09-01

    Open recirculating cooling circuits of nuclear power plants are likely to face pathogenic proliferations like Legionella and amoebae (Naegleria fowleri). To reduce such risks, biocide treatments are usually implemented. However, the selection of a treatment is never easy due to the large size of the cooling circuits. Indeed, the range of treatment options is limited due to potential health or environmental impacts of chemicals in case of chemical treatments or because of the technical difficulties to implement treatment units appropriate to the size of the cooling circuits in case of physical treatments. In the aim of finding the best compromise between efficacy, nature and quantity of chemical releases and industrial feasibility, several biocide treatments were compared at lab and pilot scale using semi-industrial pilot plants simulating recirculating cooling circuit of a nuclear power plant. These pilots were fed with river water or pre-treated water (lime softening or clari-flocculation). They were equipped with materials and surfaces representative of those found on a full-scale plant. These pilots operated at summer temperatures favoring microbial growth. Three industrial biocides were compared: chlorine, monochloramine and chlorine dioxide. The results indicate that the transit in the cooling system strongly affects the consumption of biocides and therefore their efficacy, the quantity of biocide needed and chemical releases so that the ranking of treatments defined on the basis of laboratory tests can be strongly modified. The results show different areas of consumption along the process line depending on biocides and highlight the significant role of the cooling tower. The behavior of biocides in the different compartments of the circuit (cooling tower, condenser, basins) is described and the consequences on pathogenic micro-organisms removal in bio-films and on chemical releases are considered as function of the studied biocide. Moreover, the influence of

  17. Closed string field theory

    International Nuclear Information System (INIS)

    Strominger, A.

    1987-01-01

    A gauge invariant cubic action describing bosonic closed string field theory is constructed. The gauge symmetries include local spacetime diffeomorphisms. The conventional closed string spectrum and trilinear couplings are reproduced after spontaneous symmetry breaking. The action S is constructed from the usual ''open string'' field of ghost number minus one half. It is given by the associator of the string field product which is non-vanishing because of associativity anomalies. S does not describe open string propagation because open string states associate and can thereby be shifted away. A field theory of closed and open strings can be obtained by adding to S the cubic open string action. (orig.)

  18. Pseudo Algebraically Closed Extensions

    Science.gov (United States)

    Bary-Soroker, Lior

    2009-07-01

    This PhD deals with the notion of pseudo algebraically closed (PAC) extensions of fields. It develops a group-theoretic machinery, based on a generalization of embedding problems, to study these extensions. Perhaps the main result is that although there are many PAC extensions, the Galois closure of a proper PAC extension is separably closed. The dissertation also contains the following subjects. The group theoretical counterpart of pseudo algebraically closed extensions, the so-called projective pairs. Applications to seemingly unrelated subjects, e.g., an analog of Dirichlet's theorem about primes in arithmetic progression for polynomial rings in one variable over infinite fields.

  19. Closing the gap between research and management

    Science.gov (United States)

    Deborah M. Finch; Marcia Patton-Mallory

    1993-01-01

    In this paper, we evaluate the reasons for gaps in communication between researchers and natural resource managers and identify methods to close these gaps. Gaps originate from differing patterns of language use, disparities in organizational culture and values, generation of knowledge that is too narrowly-focused to solve complex problems, failure by managers to relay...

  20. Photocatalytic reactors for treating water pollution with solar illumination, Part 3: a simplified analysis for recirculating reactors

    Energy Technology Data Exchange (ETDEWEB)

    Sagawe, G.; Bahnemann, D. [Hannover Univ. (Germany). Inst. fuer Technische Chemie; Brandi, R.J.; Cassano, A.E. [Universidad Nacional de Litoral, Santa Fe (Argentina). Inst. de Desarrollo Tecnologico para la Imdustria Quimica

    2004-11-01

    A solar photoreactor operated in the batch, recirculating mode is analyzed in terms of very simple observable variables such as the impinging photon flux, the incident area, the initial concentration, the flow rate, the reactor volume and a property defined as the Observed Photonic Efficiency. The proposed equipment is made of a tubular reactor, a tank, a pump and the connecting pipes. The analysis is formulated in terms of the photon input corresponding to an equivalent batch system that is derived as a new reaction coordinate for photoreactions. Employing several plausible approximations, the pollutant concentration evolution in the tank is cast in terms of very simple analytical solutions. Process photonic efficiencies are defined for the system operation and calculated with respect to the maximum achievable yield corresponding to the differential operation of the solar recirculating reactor. (Author)

  1. Modeling and optimization of integrated exhaust gas recirculation and multi-stage waste heat recovery in marine engines

    DEFF Research Database (Denmark)

    Kyriakidis, Fotis; Sørensen, Kim; Singh, Shobhana

    2017-01-01

    is optimized to utilize the maximum waste heat recovery. The Genetic algorithm and fmincon active-set algorithm are used to optimize the design and operation parameters for the two steam cycles. The optimization aims to find the theoretically optimal combination of the pressure levels and pinch......Waste heat recovery combined with exhaust gas recirculation is a promising technology that can address both the issue of NOx (nitrogen oxides) reduction and fuel savings by including a pressurized boiler. In the present study, a theoretical optimization of the performance of two different...... configurations of steam Rankine cycles, with integrated exhaust gas recirculation for a marine diesel engine, is presented. The first configuration employs two pressure levels and the second is configured with three-pressure levels. The models are developed in MATLAB based on the typical data of a large two...

  2. Modeling and optimization of integrated exhaust gas recirculation and multi-stage waste heat recovery in marine engines

    DEFF Research Database (Denmark)

    Kyriakidis, Fotis; Sørensen, Kim; Singh, Shobhana

    2017-01-01

    Waste heat recovery combined with exhaust gas recirculation is a promising technology that can address both the issue of NOx (nitrogen oxides) reduction and fuel savings by including a pressurized boiler. In the present study, a theoretical optimization of the performance of two different....... For the three-pressure level configuration, the optimum pressure levels are found to be 33.5/10.5/4.7 bara. The amount of waste heat recovery from the pressurized boiler is significantly higher than from the main boiler for both cycles. It is, therefore, concluded that the three-pressure level steam cycle...... configurations of steam Rankine cycles, with integrated exhaust gas recirculation for a marine diesel engine, is presented. The first configuration employs two pressure levels and the second is configured with three-pressure levels. The models are developed in MATLAB based on the typical data of a large two...

  3. Effects of a saturated layer and recirculation on nitrogen treatment performances of a single stage Vertical Flow Constructed Wetland (VFCW).

    Science.gov (United States)

    Prigent, S; Paing, J; Andres, Y; Chazarenc, F

    2013-01-01

    Upgrades to enhance nitrogen removal were tested in a 2 year old pilot vertical flow constructed wetland in spring and summer periods. The effects of a saturated layer and of recirculation were tested in particular. Two pilots (L = 2 m, W = 1.25 m, H = 1.2 m), filled with expanded schist (Mayennite(®)), were designed with hydraulic saturated layers of 20 and 40 cm at the bottom. Each pilot was fed with raw domestic wastewater under field conditions according to a hydraulic load of 15-38 cm d(-1) (i.e. 158-401 g COD (chemical oxygen demand) m(-2) d(-1)) and to recirculation rates ranging from 0% up to 150%. The initial load during the first 2 years of operation resulted in an incomplete mineralized accumulated sludge leading to total suspended solids (TSS), COD and biochemical oxygen demand (BOD5) release. A 40 cm hydraulic saturated layer enabled an increase of 5-10% total nitrogen (TN) removal compared to a 20 cm saturated layer. Recirculation allowed the dilution of raw wastewater and enhanced nitrification in a single stage. A design of 1.8 m² pe(-1) (48 cm d(-1), 191 g COD m(-2) d(-1)) with a 40 cm saturated layer and 100% recirculation enabled the French standard D4 (35 mg TSS L(-1), 125 mg COD L(-1), 25 mg BOD5 L(-1)), nitrogen concentrations below 20 mg TKN (total Kjeldahl nitrogen) L(-1) and 50 mg TN L(-1), to be met.

  4. A study of NO{sub x} reduction by fuel injection recirculation. Final report, January 1995--June 1996

    Energy Technology Data Exchange (ETDEWEB)

    Feese, J.J.; Turns, S.R.

    1996-08-01

    Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO{sub x}) in industrial burner applications. Recent small- and large-scale experiments in natural-gas fired boilers have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO{sub x}, per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. The objective of the present investigation is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO{sub x} reduction observed between FIR and FGR by studying laminar diffusion flames. The purpose of studying laminar flames is to isolate chemical effects from the effects of turbulent mixing and heat transfer, which are inherent in practical boilers. The results of both the numerical simulations and the experiments suggest that, although molecular transport and chemical kinetic phenomena are affected by the location of diluent addition depending on flow conditions, the greater effectiveness of FIR over FGR in practical applications may result from differences in turbulent mixing and heat transfer. Further research is required to understand how differences in diluent-addition location affect NO{sub x} production in turbulent flames. The present study, however, provides an underlying basis for understanding how flow conditions can affect flame chemistry. 51 figs., 7 tabs.

  5. A study of NO{sub x} reduction by fuel injection recirculation. Topical report, January 1995--May 1995

    Energy Technology Data Exchange (ETDEWEB)

    Turns, S.R.; Feese, J.J.; Frenklach, M.Y.

    1995-07-01

    Flue-gas recirculation (FGR) is a well-known method used to control oxides of nitrogen (NO{sub x}) in industrial burner applications. Recent small- and large-scale experiments by Carnot (Tustin, CA) have shown that introducing the recirculated flue gases with the fuel results in a much greater reduction in NO{sub x}, per unit mass of gas recirculated, in comparison to introducing the flue gases with the combustion air. That fuel injection recirculation (FIR) is more effective than windbox FGR is quite remarkable. At present, however, there is no definitive understanding of why FIR is more effective than conventional FGR. One speculation is that introducing the diluent gases on the fuel side of the flame affects the prompt-NO mechanism causing the greater effectiveness. The objective of our research is to ascertain whether or not chemical and/or molecular transport effects alone can explain the differences in NO{sub x} reduction observed between FIR and FGR. This knowledge will aid in the rational application and optimization of FIR in a wide variety of industrial applications. A combined modeling and experimental program is in progress to achieve the research objectives. This report discusses computer modeling studies of counterflow diffusion flames employing detailed chemical kinetics for fuel (hydrogen or methane) combustion and NO{sub x} formation. These simulations allow the calculation of NO{sub x} emission indices for a wide range of conditions. Parametric studies were conducted in which the diluent was added either on the fuel or air side of the flame for a wide range of flow conditions. Preliminary results from these simulation studies indicate that a major factor in FIR effectiveness is the differential effect on flame zone residence times associated with fuel-side versus air-side dilution.

  6. Synergistic Effects of Micro-electrolysis-Photocatalysis on Water Treatment and Fish Performance in Saline Recirculating Aquaculture System

    OpenAIRE

    Ye, Zhangying; Wang, Shuo; Gao, Weishan; Li, Haijun; Pei, Luowei; Shen, Mingwei; Zhu, Songming

    2017-01-01

    A new physico-chemical process for TAN (total ammonia nitrogen) removal and disinfection is introduced in saline recirculating aquaculture system (RAS), in which the biofilter is replaced with an integrated electrolysis cell and an activated carbon filter. The electrolysis cell which is based on micro current electrolysis combined with UV-light was self-designed. After the fundamental research, a small pilot scale RAS was operated for 30 days to verify the technical feasibility. The system wa...

  7. Design of two-column batch-to-batch recirculation to enhance performance in ion-exchange chromatography.

    Science.gov (United States)

    Persson, Oliver; Andersson, Niklas; Nilsson, Bernt

    2018-01-05

    Preparative liquid chromatography is a separation technique widely used in the manufacturing of fine chemicals and pharmaceuticals. A major drawback of traditional single-column batch chromatography step is the trade-off between product purity and process performance. Recirculation of impure product can be utilized to make the trade-off more favorable. The aim of the present study was to investigate the usage of a two-column batch-to-batch recirculation process step to increase the performance compared to single-column batch chromatography at a high purity requirement. The separation of a ternary protein mixture on ion-exchange chromatography columns was used to evaluate the proposed process. The investigation used modelling and simulation of the process step, experimental validation and optimization of the simulated process. In the presented case the yield increases from 45.4% to 93.6% and the productivity increases 3.4 times compared to the performance of a batch run for a nominal case. A rapid concentration build-up product can be seen during the first cycles, before the process reaches a cyclic steady-state with reoccurring concentration profiles. The optimization of the simulation model predicts that the recirculated salt can be used as a flying start of the elution, which would enhance the process performance. The proposed process is more complex than a batch process, but may improve the separation performance, especially while operating at cyclic steady-state. The recirculation of impure fractions reduces the product losses and ensures separation of product to a high degree of purity. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Use of Multipass Recirculation and Energy Recovery In CW SRF X-FEL Driver Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, David; Akers, Walt; Benson, Stephen V.; Biallas, George; Blackburn, Keith; Boyce, James; Bullard, Donald; Coleman, James; Dickover, Cody; Ellingsworth, Forrest; Evtushenko, Pavel; Fisk, Sally; Gould, Christopher; Gubeli, Joseph; Hannon, Fay; Hardy, David; Hernandez-Garcia, Carlos; Jordan, Kevin; Klopf, John; Kortze, J.; Legg, Robert; Li, Rui; Marchlik, Matthew; Moore, Steven W.; Neil, George; Powers, Thomas; Sexton, Daniel; Shin, Ilkyoung; Shinn, Michelle D.; Tennant, Christopher; Terzic, Balsa; Walker, Richard; Williams, Gwyn P.; Wilson, G.; Zhang, Shukui

    2010-08-01

    We discuss the use of multipass recirculation and energy recovery in CW SRF drivers for short wavelength FELs. Benefits include cost management (through reduced system footprint, required RF and SRF hardware, and associated infrastructure - including high power beam dumps and cryogenic systems), ease in radiation control (low drive beam exhaust energy), ability to accelerate and deliver multiple beams of differing energy to multiple FELs, and opportunity for seamless integration of multistage bunch length compression into the longitudinal matching scenario. Issues include all those associated with ERLs compounded by the challenge of generating and preserving the CW electron drive beam brightness required by short wavelength FELs. We thus consider the impact of space charge, BBU and other environmental wakes and impedances, ISR and CSR, potential for microbunching, intra-beam and beam-residual gas scattering, ion effects, RF transients, and halo, as well as the effect of traditional design, fabrication, installation and operational errors (lattice aberrations, alignment, powering, field quality). Context for the discussion is provided by JLAMP, the proposed VUV/X-ray upgrade to the existing Jefferson Lab FEL.

  9. Microbial and physicochemical parameters associated with Legionella contamination in hot water recirculation systems.

    Science.gov (United States)

    Serrano-Suárez, Alejandra; Dellundé, Jordi; Salvadó, Humbert; Cervero-Aragó, Sílvia; Méndez, Javier; Canals, Oriol; Blanco, Silvia; Arcas, Antoni; Araujo, Rosa

    2013-08-01

    Hot water recirculation systems (HWRS) in hotels and nursing homes, which are common in countries such as Spain, have been related to outbreaks of legionellosis. To establish the relationships of microbial and physicochemical parameters, especially protozoa, with the occurrence of Legionella in HWRS, 231 samples from hotels and nursing homes were analysed for Legionella, protozoa, heterotrophic plate counts (HPC) at 22 and 37 °C, Pseudomonas, metals, temperature and others. Legionella pneumophila was the dominant species isolated, and 22 % were sg. 1. The sampling method became particularly important in order to define which factors were involved on the occurrence of Legionella. Results showed that the bacteria and the accompanying microbiota were more abundant in the first flush water whose temperature was lower. The bacteria occurred in those samples with high HPC and were inversely correlated with high temperatures. Multivariate regression showed that a concentration above 1 × 10(5) CFU/100 mL of HPC at 37 °C, Fe above 0.095 ppm and the presence of protozoa increased significantly the risk of Legionella colonization, while univariant regression showed that the presence of Cu above 0.76 ppm and temperature above 55 °C diminished it. Therefore, to reduce the risk associated with Legionella occurrence in HWRS these parameters should be taken into consideration.

  10. Observations on side-swimming rainbow trout in water recirculation aquaculture systems.

    Science.gov (United States)

    Good, Christopher; Davidson, John; Kinman, Christin; Kenney, P Brett; Bæverfjord, Grete; Summerfelt, Steven

    2014-12-01

    During a controlled 6-month study using six replicated water recirculation aquaculture systems (WRASs), it was observed that Rainbow Trout Oncorhynchus mykiss in all WRASs exhibited a higher-than-normal prevalence of side swimming (i.e., controlled, forward swimming but with misaligned orientation such that the fish's sagittal axis is approximately parallel to the horizontal plane). To further our understanding of this abnormality, a substudy was conducted wherein side swimmers and normally swimming fish were selectively sampled from each WRAS and growth performance (length, weight), processing attributes (fillet yield, visceral index, ventrum [i.e., thickness of the ventral "belly flap"] index), blood gas and chemistry parameters, and swim bladder morphology and positioning were compared. Side swimmers were found to be significantly smaller in length and weight and had less fillet yield but higher ventrum indices. Whole-blood analyses demonstrated that, among other things, side swimmers had significantly lower whole-blood pH and higher Pco2. Side swimmers typically exhibited swim bladder malformations, although the positive predictive value of this subjective assessment was only 73%. Overall, this study found several anatomical and physiological differences between side-swimming and normally swimming Rainbow Trout. Given the reduced weight and fillet yield of market-age side swimmers, producers would benefit from additional research to reduce side-swimming prevalence in their fish stocks.

  11. Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary Formations

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Mike; Detwiler, Russell L; Lao, Kang; Serajian, Vahid; Elkhoury, Jean; Diessl, Julia; White, Nicky

    2012-09-30

    There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. Terralog USA, in collaboration with the University of California, Irvine (UCI), are currently investigating advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. This two-year research project, funded by the US Department of Energy, includes combined efforts for: 1) Resource characterization; 2) Small and large scale laboratory investigations; 3) Numerical simulation at both the laboratory and field scale; and 4) Engineering feasibility studies and economic evaluations. The research project is currently in its early stages. This paper summarizes our technical approach and preliminary findings related to potential resources, small-scale laboratory simulation, and supporting numerical simulation efforts.

  12. Efficient random subcloning of DNA sheared in a recirculating point-sink flow system.

    Science.gov (United States)

    Oefner, P J; Hunicke-Smith, S P; Chiang, L; Dietrich, F; Mulligan, J; Davis, R W

    1996-10-15

    Based on a high-performance liquid chromatographic pump, we have built a device that allows recirculation of DNA through a 63-microm orifice with ensuing fractionation to a minimum fragment size of approximately 300 base pairs. Residence time of the DNA fragments in the converging flow created by a sudden contraction was found to be sufficiently long to allow extension of the DNA molecules into a highly extended conformation and, hence, breakage to occur at midpoint. In most instances, 30 passages sufficed to obtain a narrow size distribution, with >90% of the fragments lying within a 2-fold size distribution. The shear rate required to achieve breakage was found to be inversely proportional to the 1.0 power of the molecular weight. Compared with a restriction digest, up to 40% of all fragments could be cloned directly, with only marginal improvements in cloning efficiency having been observed upon prior end repair with Klenow, T4 polymerase or T4 polynucleotide kinase. Sequencing revealed a fairly random distribution of the fragments.

  13. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    International Nuclear Information System (INIS)

    Bohn, C.L.

    1997-01-01

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 μm wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design

  14. Integrated process control for recirculating cooling water treatment in the coal chemical industry.

    Science.gov (United States)

    Pei, Y S; Guo, W; Yang, Z F

    2011-01-01

    This work focused on the integrated process of the recirculating cooling water (RCW) treatment to achieve approximate zero emission in the coal chemical industry. The benefits of fractional and comprehensive RCW treatment were quantified and qualified by using a water and mass balance approach. Limits of cycle of concentrations and some encountered bottlenecks were used to ascertain set target limits for different water sources. Makeup water was mixed with water produced from reverse osmosis (RO) in the proportion of 6:4, which notably reduced salts discharge. Side infiltration, which settled down suspended solids, can reduce energy consumption by over 40%. An automated on-line monitoring organic phosphorus inhibitor feed maintains the RCW system stability in comparison to the manual feed. Two-step electrosorb technology (EST) instead of an acid feed can lead cycle of concentration of water to reach 7.0. The wastewater from RO, EST and filter was transferred into a concentration treatment system where metallic ions were adsorbed by permanent magnetic materials. Separation of water and salts was completed by using a magnetic disc separator. Applying the integrated process in a coal chemical industry, a benefit of 1.60 million Yuan annually in 2 years was gained and approximate zero emission was achieved. Moreover, both technical and economic feasibility were demonstrated in detail.

  15. Energy stability in recirculating, energy-recovering linacs in the presence of a FEL

    International Nuclear Information System (INIS)

    Merminga, L.; Bisognano, J.; Delayen, J.R.

    1996-01-01

    Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs (free electron lasers). Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M 56 , phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. An analytical model which includes amplitude and phase feedback, has been developed to study the stability of the system for small perturbations from equilibrium. The interaction of the electron beam with the FEL is a major perturbation which affects both the stability of the system and development of startup and recovery scenarios. To simulate the system's response to such large parameter variations, a numerical model of the beam-cavity interaction has been developed which includes low level rf feedback, phase oscillations and beam loss instabilities and the FEL interaction. Agreement between the numerical model and the linear theory has been demonstrated in the limit of small perturbations. In addition, the model has been benchmarked against experimental data obtained during CEBAF's high current operation. Numerical simulations have been performed for the high power IR DEMO approved for construction at CEBAF

  16. Effect of exhaust gas recirculation on diesel engine nitrogen oxide reduction operating with jojoba methyl ester

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, H.E. [Mechanical Power Department, Faculty of Engineering, Mattaria, Helwan University, 9 k Eltaaweniat, Nasr Road, P.O. Box 11718, Cairo (Egypt)

    2009-10-15

    Jojoba methyl ester (JME) has been used as a renewable fuel in numerous studies evaluating its potential use in diesel engines. These studies showed that this fuel is good gas oil substitute but an increase in the nitrogenous oxides emissions was observed at all operating conditions. The aim of this study mainly was to quantify the efficiency of exhaust gas recirculation (EGR) when using JME fuel in a fully instrumented, two-cylinder, naturally aspirated, four-stroke direct injection diesel engine. The tests were carried out in three sections. Firstly, the measured performance and exhaust emissions of the diesel engine operating with diesel fuel and JME at various speeds under full load are determined and compared. Secondly, tests were performed at constant speed with two loads to investigate the EGR effect on engine performance and exhaust emissions including nitrogenous oxides (NO{sub x}), carbon monoxide (CO), unburned hydrocarbons (HC) and exhaust gas temperatures. Thirdly, the effect of cooled EGR with high ratio at full load on engine performance and emissions was examined. The results showed that EGR is an effective technique for reducing NO{sub x} emissions with JME fuel especially in light-duty diesel engines. With the application of the EGR method, the CO and HC concentration in the engine-out emissions increased. For all operating conditions, a better trade-off between HC, CO and NO{sub x} emissions can be attained within a limited EGR rate of 5-15% with very little economy penalty. (author)

  17. Broodstock management of the fine flounder Paralichthys adspersus (Steindachner, 1867 using recirculating aquaculture systems

    Directory of Open Access Journals (Sweden)

    Lili Carrera

    2013-03-01

    Full Text Available The present study describes the methodology used at IMARPE for the capture, acclimation and management of P. adspersus broodstock using recirculating aquaculture systems (RAS. RAS improved the water quality and maintained the environmental parameters during the acclimation period, temperature (17.2±1°C, oxygen (8.1±0.7 mg L-1, pH (7.3±0.2, ammonia (0.004±0.003 mg L-1, nitrite (0.52±0.2 mg L-1 and nitrate (3.45±2.6 mg L-1. Fish began to be fed normally from day 15 post-capture, once or twice a day using live fish (Odonthestes regia regia, Mugil cephalus, crustacean (Emerita analoga, fresh food (Engraulis ringens and Dosidicus gigas and artificial feed. A significant loss in the weight of the fish was registered during the first days of captivity, followed by a continuous increase in both sexes. The specific growth rate was positive from the third month of captivity, being the relative growth rate 24.5% and 16.2% in August 2010 in males and females, respectively. Different internal and external parasites were detected in the fish, being Entobdella sp. and Philometra sp. the prevailing parasites observed during samplings.

  18. Rapid, k-space linear wavelength scanning laser source based on recirculating frequency shifter.

    Science.gov (United States)

    Wan, Minggui; Wang, Lin; Li, Feng; Cao, Yuan; Wang, Xudong; Feng, Xinhuan; Guan, Bai-Ou; Wai, P K A

    2016-11-28

    We propose and successfully demonstrate a k-space linear and self-clocked wavelength scanning fiber laser source based on recirculating frequency shifting (RFS). The RFS is realized with a high speed electro-optic dual parallel Mach-Zehnder modulator operating at the state of carrier suppressed single sideband modulation. A gated short pulse is injected into an amplified RFS loop to generate the wavelength scanning pulse train. We find that the accumulation of in-band amplified spontaneous emission (ASE) noise over multiple scanning periods will saturate the erbium-doped fiber amplifier and impede the amplification to the pulse signal in the RFS loop. To overcome the degradation of temporal signal due to the accumulation of ASE noise over multiple scanning periods, we insert a modulated optical switch into the RFS loop to completely attenuate the in-band ASE noise at the end of each scanning period. The signal to noise ratio of the temporal pulsed signal is greatly enhanced. K-space linear and self-clocked wavelength scanning fiber laser sources in 6.1 nm/7.2 nm scanning range with 20 GHz/30 GHz frequency shifting are successfully demonstrated.

  19. Recycling Monoethylene Glycol (MEG from the Recirculating Waste of an Ethylene Oxide Unit

    Directory of Open Access Journals (Sweden)

    Moayed Mohsen

    2017-06-01

    Full Text Available In the ethylene glycol generation unit of petrochemical plants, first a reaction of ethylene oxide takes place which is then followed by other side reactions. These reactions include water absorption with ethylene oxide, which leads to the generation of formaldehyde and acetaldehyde. Over the lifetime of the alpha-alumina-based silver catalyst there is an increase in side reactions, increasing the amount of the formaldehyde and acetaldehyde generated by the ethylene oxide reactor which leads to reduced MEG product purity. Given the need of a petrochemical complex to further strip the aldehyde (formaldehyde and acetaldehyde to increase the quality of the MEG and increase the lifetime of the alpha-alumina-based silver catalyst, resin beds are designed and their surface absorption capacity is investigated to optimize aldehyde (formaldehyde and acetaldehyde removal in the recirculating water flow of the ethylene oxide unit. Experiments show that the ion exchange system based on strong anionic resin pre-treated with a sodium bisulfite solution can reduce the aldehyde level from about 300ppm to less than 5ppm. After the resin is saturated with aldehyde, the resin can be recycled using the sodium bisulfite solution which is a cheap chemical substance.

  20. Liquid Hydrogen Recirculation System for Forced Flow Cooling Test of Superconducting Conductors

    Science.gov (United States)

    Shirai, Y.; Kainuma, T.; Shigeta, H.; Shiotsu, M.; Tatsumoto, H.; Naruo, Y.; Kobayashi, H.; Nonaka, S.; Inatani, Y.; Yoshinaga, S.

    2017-12-01

    The knowledge of forced flow heat transfer characteristics of liquid hydrogen (LH2) is important and necessary for design and cooling analysis of high critical temperature superconducting devices. However, there are few test facilities available for LH2 forced flow cooling for superconductors. A test system to provide a LH2 forced flow (∼10 m/s) of a short period (less than 100 s) has been developed. The test system was composed of two LH2 tanks connected by a transfer line with a controllable valve, in which the forced flow rate and its period were limited by the storage capacity of tanks. In this paper, a liquid hydrogen recirculation system, which was designed and fabricated in order to study characteristics of superconducting cables in a stable forced flow of liquid hydrogen for longer period, was described. This LH2 loop system consists of a centrifugal pump with dynamic gas bearings, a heat exchanger which is immersed in a liquid hydrogen tank, and a buffer tank where a test section (superconducting wires or cables) is set. The buffer tank has LHe cooled superconducting magnet which can produce an external magnetic field (up to 7T) at the test section. A performance test was conducted. The maximum flow rate was 43.7 g/s. The lowest temperature was 22.5 K. It was confirmed that the liquid hydrogen can stably circulate for 7 hours.

  1. Integrated Multi-Trophic Recirculating Aquaculture System for Nile Tilapia (Oreochlomis niloticus

    Directory of Open Access Journals (Sweden)

    Puchong Sri-uam

    2016-06-01

    Full Text Available Three densities of the sex-reversed male Nile tilapia, Oreochromis niloticus (20, 25, 50 fish/m3 were cultivated in an integrated multi-trophic recirculating aquaculture system (IMRAS that involves the ecological relationship between several living organisms, i.e., phytoplankton, zooplankton, and aquatic plants. The results indicated that, by providing proper interdependency between various species of living organisms, the concentrations of ammonia, nitrite, nitrate, and phosphate in the system were maintained below dangerous levels for Nile tilapia throughout the cultivation period. The highest wet weight productivity of Nile tilapia of 11 ± 1 kg was achieved at a fish density of 50 fish/m3. The aquatic plants in the treatment tank could effectively uptake the unwanted nitrogen (N and phosphorus (P compounds with the highest removal efficiencies of 9.52% and 11.4%, respectively. The uptake rates of nitrogen and phosphorus by aquatic plants could be ranked from high to low as: Egeria densa > Ceratophyllum demersum > Vallisneria spiralis and Vallisneria americana > Hygrophila difformis. The remaining N was further degraded through nitrification process, whereas the remaining P could well precipitate in the soil sediment in the treatment tank.

  2. Intestinal microbiota of healthy and unhealthy Atlantic salmon Salmo salar L. in a recirculating aquaculture system

    Science.gov (United States)

    Wang, Chun; Sun, Guoxiang; Li, Shuangshuang; Li, Xian; Liu, Ying

    2017-04-01

    The present study sampled the intestinal content of healthy and unhealthy Atlantic salmon (Salmo salar L.), the ambient water of unhealthy fish, and the biofilter material in the recirculating aquaculture system (RAS) to understand differences in the intestinal microbiota. The V4-V5 regions of the prokaryotic 16S rRNA genes in the samples were analyzed by MiSeq high-throughput sequencing. The fish were adults with no differences in body length or weight. Representative members of the intestinal microbiota were identified. The intestinal microbiota of the healthy fish included Proteobacteria (44.33%), Actinobacteria (17.89%), Bacteroidetes (15.25%), and Firmicutes (9.11%), among which the families Micrococcaceae and Oxalobacteraceae and genera Sphingomonas, Streptomyces, Pedobacter, Janthinobacterium, Burkholderia, and Balneimonas were most abundant. Proteobacteria (70.46%), Bacteroidetes (7.59%), and Firmicutes (7.55%) dominated the microbiota of unhealthy fish, and Chloroflexi (2.71%), and Aliivibrio and Vibrio as well as genera in the family Aeromonadaceae were most strongly represented. Overall, the intestinal hindgut microbiota differed between healthy and unhealthy fish. This study offers a useful tool for monitoring the health status of fish and for screening the utility of probiotics by studying the intestinal microbiota.

  3. Mono-fermentation of chicken manure: ammonia inhibition and recirculation of the digestate.

    Science.gov (United States)

    Nie, Hong; Jacobi, H Fabian; Strach, Katrin; Xu, Chunming; Zhou, Hongjun; Liebetrau, Jan

    2015-02-01

    The effects of ammonia concentration on the performance and stability of mono-fermentation of chicken manure were investigated in a lab-scale continuous stirred tank reactor at 40 °C. Technical stripping was performed to remove ammonia from the liquid fraction of digestate, and the entire product was recycled to the fermenter to control ammonia concentration in the fermenter. Organic loading rate (OLR) of 5.3 gVS/(L d) was achieved with an average free ammonia nitrogen (FAN) concentration of 0.77 g/L and a specific gas yield of 0.39 L/gVS. When OLR was increased to 6.0 gVS/(L d), stable operation could be obtained with an average FAN concentration of 0.86 g/L and a specific gas yield of 0.27 L/gVS. Mono-fermentation of chicken manure was successfully carried out at high ammonia concentrations. Controlled recirculation of treated liquid fraction of digestate could be a solution in large-scale application for both: to avoid ammonia inhibition and minimize digestate. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Thromboelastography used to assess coagulation during treatment with molecular adsorbent recirculating system.

    Science.gov (United States)

    Doria, Cataldo; Mandalà, Lucio; Smith, Jan D; Caruana, Giuseppe; Scott, Victor L; Gruttadauria, Salvatore; Magnone, Mario; Marino, Ignazio R

    2004-08-01

    Coagulopathy is a life-threatening complication of liver cirrhosis. We describe the effect of molecular adsorbent recirculating system (MARS), a cell-free dialysis technique, on the blood coagulation of cirrhotic patients. From February 2002 to July 2002, nine patients--five males (55.5%) and four females (44.4%), age 47-70 yr (median 56)--underwent 12 courses (4-7 sessions each) of MARS. Patients were treated for the following indications: six (66.6%) acute-on-chronic hepatic failure, three (33.3%) intractable pruritus. Platelet count, prothrombin time (PT), international standardized ratio and thromboelastography were measured before and after each MARS session. Coagulation factors II, V, VII, VIII, IX, X, XI, XII, XIII, von Willebrand, lupus anticoagulant, protein C, protein S, antithrombin III, plasminogen, alpha 2 antiplasmin, D-dimer, fibrin monomers, complement, and C(1) inactivator were measured before and at the end of each MARS treatment. We found a statistically significant difference (p < 0.05) in the platelet count, PT, all the thromboelastograph variables (reaction and constant time, alpha angle, and maximal amplitude), factor VIII, von Willebrand, and D-dimer, when measured before and after MARS. Previous reports have shown amelioration of blood coagulation following MARS treatments. However, we document that MARS induces coagulopathy through a platelet-mediated mechanism, whereby platelet may be mechanically destroyed during the passage of blood through the filters and lines. An alternative postulated mechanism is an immune-mediated platelet disruption - coagulopathy.

  5. Countermeasure against thermal fatigue crack of primary loop recirculation pump in BWR

    International Nuclear Information System (INIS)

    Noda, Hiroshi; Narabayashi, Tadashi; Takahashi, Yuuji

    2008-01-01

    The reactor water was fed to the purge water of the mechanical seal on the original design of the primary loop recirculation pump. Because the mechanical seal had a short life due to the cruds in the reactor water, the clean purge water was adopted instead of the reactor water. After this modification, the shallow cracks were found on the surface of the pump shaft and casing cover due to the temperature fluctuation between the cold purge water and the hot pump discharge water. The fundamental mechanism and countermeasure were investigated by scale test, mock-up test and so on. The flow barrier with a heater was contrived through these tests. It has been introduced gradually in operating and constructing PLR pumps after its completion in 1995. The PLR pumps are overhauled around every 10 years in Japan. The first overhaul of the PLR pumps showed no cracks around the pump shaft and casing over after 10 years' operation. This paper presents both its development process and inspection results. (author)

  6. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    1997-06-01

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design.

  7. Temporal and spatial pore water pressure distribution surrounding a vertical landfill leachate recirculation well.

    Science.gov (United States)

    Kadambala, Ravi; Townsend, Timothy G; Jain, Pradeep; Singh, Karamjit

    2011-05-01

    Addition of liquids into landfilled waste can result in an increase in pore water pressure, and this in turn may increase concerns with respect to geotechnical stability of the landfilled waste mass. While the impact of vertical well leachate recirculation on landfill pore water pressures has been mathematically modeled, measurements of these systems in operating landfills have not been reported. Pressure readings from vibrating wire piezometers placed in the waste surrounding a liquids addition well at a full-scale operating landfill in Florida were recorded over a 2-year period. Prior to the addition of liquids, measured pore pressures were found to increase with landfill depth, an indication of gas pressure increase and decreasing waste permeability with depth. When liquid addition commenced, piezometers located closer to either the leachate injection well or the landfill surface responded more rapidly to leachate addition relative to those far from the well and those at deeper locations. After liquid addition stopped, measured pore pressures did not immediately drop, but slowly decreased with time. Despite the large pressures present at the bottom of the liquid addition well, much smaller pressures were measured in the surrounding waste. The spatial variation of the pressures recorded in this study suggests that waste permeability is anisotropic and decreases with depth.

  8. Numerical and Experimental Modeling of the Recirculating Melt Flow Inside an Induction Crucible Furnace

    Science.gov (United States)

    Asad, Amjad; Bauer, Katrin; Chattopadhyay, Kinnor; Schwarze, Rüdiger

    2018-02-01

    In the paper, a new water model of the turbulent recirculating flow in an induction furnace is introduced. The water model was based on the principle of the stirred vessel used in process engineering. The flow field in the water model was measured by means of particle image velocimetry in order to verify the model's performance. Here, it is indicated that the flow consists of two toroidal vortices similar to the flow in the induction crucible furnace. Furthermore, the turbulent flow in the water model is investigated numerically by adopting eddy-resolving turbulence modeling. The two toroidal vortices occur in the simulations as well. The numerical approaches provide identical time-averaged flow patterns. Moreover, a good qualitative agreement is observed on comparing the experimental and numerical results. In addition, a numerical simulation of the melt flow in a real induction crucible furnace was performed. The turbulent kinetic energy spectrum of the flow in the water model was compared to that of the melt flow in the induction crucible furnace to show the similarity in the nature of turbulence.

  9. A distributed, mobile-immobile domain transport model based on local mass transfer with recirculation zones

    Science.gov (United States)

    Zhou, J.; Wang, L.; Chen, Y.; Cardenas, M. B.

    2017-12-01

    Eddies or recirculation zones and stagnation zones are common in many environmental, engineering, and geophysical flow phenomena. Near rough boundaries, eddies are persistently and distinctly separate to the bulk flow. This leads to delays and long tails in the chemical transport by fluids since the entities being transported can be trapped and later released from the eddies. Here we provide a process-based insight on the anomalous transport induced by eddies using computational experiments with fully resolved flow and transport fields within rough fractures. A computationally tractable and objective eddy detection technique was developed. This allowed for direct insight into the mass transfer process at the interface between eddies and its neighboring main flow channel. A distributed mobile-immobile model with high fidelity has been proposed that incorporates the full local information of eddies and transport within the eddy. This local information includes eddy geometry and mass transfer coefficients. Taking this into account is critical for prediction of anomalous transport, and further provides a physically-based approach for modifying the classic mobile-immobile domain model into a distributed one. The methods and results in this study can serve as the foundation for the analysis and prediction of flow and transport phenomena in different environmental settings with immobile zones.

  10. Analysis of benefits of using internal exhaust gas recirculation in biogas-fueled HCCI engines

    International Nuclear Information System (INIS)

    Kozarac, Darko; Vuilleumier, David; Saxena, Samveg; Dibble, Robert W.

    2014-01-01

    Highlights: • The influence of EGR on combustion of biogas fueled HCCI was investigated. • The aim was to reduce intake temperature requirement by internal EGR. • Combustion products caused the delay of combustion in similar conditions. • Internal EGR enabled by negative valve overlap increased cylinder temperature. • This increase was not enough to significantly reduce the intake temperature. - Abstract: This paper describes a numerical study that analyzed the influence of combustion products (CP) concentration on the combustion characteristics (combustion timing and combustion duration) of a biogas fueled homogeneous charge compression ignition (HCCI) engine and the possibility of reducing the high intake temperature requirement necessary for igniting biogas in a HCCI engine by using internal exhaust gas recirculation (EGR) enabled by negative valve overlap (NVO). An engine model created in AVL Boost, and validated against experimental engine data, was used in this study. The results show, somewhat counter-intuitively, that when CP concentrations are increased the required intake temperature for maintaining the same combustion timing must be increased. When greater NVO is used to increase the in-cylinder CP concentration, the in-cylinder temperature does increase, but the chemical dilution influence of CP almost entirely counteracts this thermal effect. Additionally, it has been observed that with larger fractions of CP some instability of combustion in the calculation was obtained which indicates that the increase of internal EGR might produce some combustion instability

  11. Experimental evaluation of square bar and fractal grid-generated turbulent flow inside recirculating water tunnel

    Science.gov (United States)

    Bornemeier, Matthew; Luznik, Luksa

    2017-11-01

    High resolution, two dimensional PIV measurements of grid-generated turbulence in the US Naval Academy's recirculating water tunnel (1.8m test section with 0.41m x 0.41m cross sectional area) are presented for two different grid designs. The first grid is a uniform square bar grid with mesh width, M =3.9cm, bar thickness t0 = 1cm, a streamwise thickness of 1cm and resulting solidity of 44%, similar to the conventional grid used by Krogstad and Davidson (2012). The other is Mazellier & Vassilicos' (2010) square fractal grid, SFG17, with fractal iteration count, N =4, thickness ratio tr = 17 and length ratio Lr = 8. Grid patterns differ from the published designs by a circular hole with 4.30cm diameter in the middle that will accept, in future experiments, a shaft connected to an axisymmetric rotating wake generator with diameter, D. Grids were designed to generate turbulence of specific integral length scale of O(D) and intensity of 6% at the prescribed downstream location. Mean tunnel centerline velocity is 2 m/s and measurements are made in a streamwise vertical center plane with nominal individual field of view (FOV) of 12x8 cm2. Spatial coverage in the test section is accomplished by ``tiling'' individual FOV with approximately 2cm overlap. Results will focus on characterizing resulting turbulence in the test section and discussion will include comparison between published results and the present measurements.

  12. A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system.

    Science.gov (United States)

    Endut, Azizah; Jusoh, A; Ali, N; Wan Nik, W B; Hassan, A

    2010-03-01

    The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate. 2009 Elsevier Ltd. All rights reserved.

  13. Closed Claim Query File

    Data.gov (United States)

    Social Security Administration — This file is used to hold information about disability claims that have been closed and have been selected for sampling.Sampling is the process whereby OQR reviews...

  14. Recirculation or artificial aeration in vertical flow constructed wetlands: a comparative study for treating high load wastewater.

    Science.gov (United States)

    Foladori, Paola; Ruaben, Jenny; Ortigara, Angela R C

    2013-12-01

    Vertical subsurface-flow constructed wetlands at pilot-scale have been applied to treat high hydraulic and organic loads by implementing the following configurations: (1) intermittent recirculation of the treated wastewater from the bottom to the top of the bed, (2) intermittent artificial aeration supplied at the bottom of the bed and (3) the combination of both. These configurations were operated with a saturated bottom layer for a 6h-treatment phase, followed by a free drainage phase prior to a new feeding. COD removal efficiency was 85-90% in all the configurations and removed loads were 54-70 gCOD m(-2)d(-1). The aerated and recirculated wetland resulted in a higher total nitrogen removal (8.6 gN m(-2)d(-1)) due to simultaneous nitrification/denitrification, even in the presence of intermittent aeration (6.8 Nm(3)m(-2)d(-1)). The extra investment needed for implementing aeration/recirculation would be compensated for by a reduction of the surface area per population equivalent, which decreased to 1.5m(2)/PE. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Modulation of ATP/ADP concentration at the endothelial surface by shear stress: effect of flow recirculation.

    Science.gov (United States)

    Choi, Hyo Won; Ferrara, Katherine W; Barakat, Abdul I

    2007-04-01

    The extracellular presence of the adenine nucleotides ATP and ADP induces calcium mobilization in vascular endothelial cells (ECs). ATP/ADP concentration at the EC surface is determined by a balance of convective-diffusive transport to and from the EC surface, hydrolysis by ectonucleotidases at the cell surface, and flow-induced ATP release from ECs. Our previous numerical simulations in a parallel plate geometry had demonstrated that flow-induced ATP release has a profound effect on nucleotide concentration at the EC surface. In the present study, we have extended the modeling to probe the impact of flow separation and recirculation downstream of a backward facing step (BFS) on ATP/ADP concentration at the EC surface. The results show that for both steady and pulsatile flow over a wide range of wall shear stresses, the ATP+ADP concentration at the EC surface is considerably lower within the flow recirculation region than in areas of undisturbed flow outside the recirculation zone. Pulsatile flow also leads to sharp temporal gradients in nucleotide concentration. If confirmed experimentally, the present findings suggest that disturbed and undisturbed flow may affect EC calcium mobilization differently. Such differences might, in turn, contribute to the observed endothelial dysfunction in regions of disturbed flow.

  16. Photocatalytic reactors for treating water pollution with solar illumination: a simplified analysis for n-steps flow reactors with recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Sagawe, G.; Bahnemann, D. [Universitaet Hannover (Germany). Institut fuer Technische Chemie; Brandi, R.J.; Cassano, A.E. [INTEC Universidad Nacional del Litoral and CONICET, Sante Fe (Argentina)

    2005-09-01

    The concentration of dissolved oxygen in water, in equilibrium with atmospheric air (ca. 8 ppm at 20{sup o}C), defines the limits of all practical oxidizing processes for removing pollutants in photocatalytic reactors. To solve this limitation, an alternative approach to that of a continuously aerated reactor is the use of a recirculating system with aeration performed after every cycle at the reactor entering stream. As defined by the nature of a single recirculating step (the need of a reactor operation at a rather low concentration range), this procedure results in a very low photonic efficiency (thus requiring a large photon collecting area and consequently increasing the capital cost). The design engineer will have to resort to a series of several reactors with recirculation. This solution may then lead to a very high Photonic Efficiency for the entire process (i.e., a reduced light harvesting area) at the price of an increase in the required capital cost (due to the larger number of reactors). This paper provides a very simple analysis and analytical expressions that can be used to estimate, for a desired degree of degradation, a trade-off solution between a high number of reactors and a very large surface area to collect the solar photons. (author)

  17. Close binary stars

    International Nuclear Information System (INIS)

    Larsson-Leander, G.

    1979-01-01

    Studies of close binary stars are being persued more vigorously than ever, with about 3000 research papers and notes pertaining to the field being published during the triennium 1976-1978. Many major advances and spectacular discoveries were made, mostly due to increased observational efficiency and precision, especially in the X-ray, radio, and ultraviolet domains. Progress reports are presented in the following areas: observational techniques, methods of analyzing light curves, observational data, physical data, structure and models of close binaries, statistical investigations, and origin and evolution of close binaries. Reports from the Coordinates Programs Committee, the Committee for Extra-Terrestrial Observations and the Working Group on RS CVn binaries are included. (Auth./C.F.)

  18. Closing global material loops

    DEFF Research Database (Denmark)

    Prosman, Ernst-Jan; Wæhrens, Brian Vejrum; Liotta, Giacomo

    2017-01-01

    Replacing virgin materials with waste materials, a practice known as Industrial Symbiosis (IS), has been identified as a key strategy for closing material loops. This article adopts a critical view on geographic proximity and external coordinators – two key enablers of IS. By ‘uncovering’ a case ...... for geographic proximity and external coordinators. In doing so, our insights into firm-level challenges of long-distance IS exchanges contribute to closing global material loops by increasing the number of potential circular pathways....

  19. Closed Loop Subspace Identification

    Directory of Open Access Journals (Sweden)

    Geir W. Nilsen

    2005-07-01

    Full Text Available A new three step closed loop subspace identifications algorithm based on an already existing algorithm and the Kalman filter properties is presented. The Kalman filter contains noise free states which implies that the states and innovation are uneorre lated. The idea is that a Kalman filter found by a good subspace identification algorithm will give an output which is sufficiently uncorrelated with the noise on the output of the actual process. Using feedback from the output of the estimated Kalman filter in the closed loop system a subspace identification algorithm can be used to estimate an unbiased model.

  20. Next Generation Pressurized Oxy-Coal Combustion: High Efficiency and No Flue Gas Recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Rue, David

    2013-09-30

    The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculated to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis

  1. SELECTIVE NOx RECIRCULATION FOR STATIONARY LEAN-BURN NATURAL GAS ENGINES

    Energy Technology Data Exchange (ETDEWEB)

    Nigel Clark; Gregory Thompson; Richard Atkinson; Chamila Tissera; Matt Swartz; Emre Tatli; Ramprabhu Vellaisamy

    2005-01-01

    The research program conducted at the West Virginia University Engine and Emissions Research Laboratory (EERL) is working towards the verification and optimization of an approach to remove nitric oxides from the exhaust gas of lean burn natural gas engines. This project was sponsored by the US Department of Energy, National Energy Technology Laboratory (NETL) under contract number: DE-FC26-02NT41608. Selective NOx Recirculation (SNR) involves three main steps. First, NOx is adsorbed from the exhaust stream, followed by periodic desorption from the aftertreatment medium. Finally the desorbed NOx is passed back into the intake air stream and fed into the engine, where a percentage of the NOx is decomposed. This reporting period focuses on the NOx decomposition capability in the combustion process. Although researchers have demonstrated NOx reduction with SNR in other contexts, the proposed program is needed to further understand the process as it applies to lean burn natural gas engines. SNR is in support of the Department of Energy goal of enabling future use of environmentally acceptable reciprocating natural gas engines through NOx reduction under 0.1 g/bhp-hr. The study of decomposition of oxides of nitrogen (NOx) during combustion in the cylinder was conducted on a 1993 Cummins L10G 240 hp lean burn natural gas engine. The engine was operated at different air/fuel ratios, and at a speed of 800 rpm to mimic a larger bore engine. A full scale dilution tunnel and analyzers capable of measuring NOx, CO{sub 2}, CO, HC concentrations were used to characterize the exhaust gas. Commercially available nitric oxide (NO) was used to mimic the NOx stream from the desorption process through a mass flow controller and an injection nozzle. The same quantity of NOx was injected into the intake and exhaust line of the engine for 20 seconds at various steady state engine operating points. NOx decomposition rates were obtained by averaging the peak values at each set point minus

  2. Selective NOx Recirculation for Stationary Lean-Burn Natural Gas Engines

    Energy Technology Data Exchange (ETDEWEB)

    Nigel N. Clark

    2006-12-31

    Nitric oxide (NO) and nitrogen dioxide (NO2) generated by internal combustion (IC) engines are implicated in adverse environmental and health effects. Even though lean-burn natural gas engines have traditionally emitted lower oxides of nitrogen (NOx) emissions compared to their diesel counterparts, natural gas engines are being further challenged to reduce NOx emissions to 0.1 g/bhp-hr. The Selective NOx Recirculation (SNR) approach for NOx reduction involves cooling the engine exhaust gas and then adsorbing the NOx from the exhaust stream, followed by the periodic desorption of NOx. By sending the desorbed NOx back into the intake and through the engine, a percentage of the NOx can be decomposed during the combustion process. SNR technology has the support of the Department of Energy (DOE), under the Advanced Reciprocating Engine Systems (ARES) program to reduce NOx emissions to under 0.1 g/bhp-hr from stationary natural gas engines by 2010. The NO decomposition phenomenon was studied using two Cummins L10G natural gas fueled spark-ignited (SI) engines in three experimental campaigns. It was observed that the air/fuel ratio ({lambda}), injected NO quantity, added exhaust gas recirculation (EGR) percentage, and engine operating points affected NOx decomposition rates within the engine. Chemical kinetic model predictions using the software package CHEMKIN were performed to relate the experimental data with established rate and equilibrium models. The model was used to predict NO decomposition during lean-burn, stoichiometric burn, and slightly rich-burn cases with added EGR. NOx decomposition rates were estimated from the model to be from 35 to 42% for the lean-burn cases and from 50 to 70% for the rich-burn cases. The modeling results provided an insight as to how to maximize NOx decomposition rates for the experimental engine. Results from this experiment along with chemical kinetic modeling solutions prompted the investigation of rich-burn operating conditions

  3. Population pharmacokinetic modelling of the enterohepatic recirculation of diclofenac and rofecoxib in rats

    Science.gov (United States)

    Huntjens, D R H; Strougo, A; Chain, A; Metcalf, A; Summerfield, S; Spalding, D J M; Danhof, M; Della Pasqua, O

    2008-01-01

    Background and purpose: Enterohepatic recirculation (EHC) is a common pharmacokinetic phenomenon that has been poorly modelled in animals. The presence of EHC leads to the appearance of multiple peaks in the concentration-time profile and increased exposure, which may have implications for drug effect and extrapolation across species. The aim of this investigation was to develop a population pharmacokinetic model for diclofenac and rofecoxib that describes EHC and to assess its consequence for the pharmacodynamics of both drugs. Experimental approach: The pharmacokinetics of diclofenac and rofecoxib was characterized in male rats following intravenous, intraperitoneal and oral administration. Blood samples were collected at pre-defined time points after dosing to determine plasma concentrations over time. A parametric approach using nonlinear mixed effects modelling was applied to describe EHC, whilst simulations were used to evaluate its impact on PGE2 inhibition. Key results: For diclofenac, EHC was described by a compartmental model with periodic transfer rate and metabolite formation rate. For rofecoxib, EHC modelling required a conversion compartment with first-order recycling rate and lag time. Based on model predictions, EHC causes an increase of 95% in the systemic exposure to diclofenac and of 15% in the exposure to rofecoxib. In addition, EHC prolongs the inhibition of PGE2 and increases the duration of the anti-inflammatory effect (24 h for rofecoxib 10 mg kg−1) without affecting maximum inhibition. Conclusions and implications: Our findings show the relevance of exploring EHC in a quantitative manner to accurately interpret pharmacodynamic findings in vivo, in particular when scaling across species. PMID:18193075

  4. Exhaust gas recirculation – Zero dimensional modelling and characterization for transient diesel combustion control

    International Nuclear Information System (INIS)

    Asad, Usman; Tjong, Jimi; Zheng, Ming

    2014-01-01

    Highlights: • Zero-dimensional EGR model for transient diesel combustion control. • Detailed analysis of EGR effects on intake, cylinder charge and exhaust properties. • Intake oxygen validated as an operating condition-independent measure of EGR. • Quantified EGR effectiveness in terms of NOx emission reduction. • Twin lambda sensor technique for estimation of EGR/in-cylinder parameters. - Abstract: The application of exhaust gas recirculation (EGR) during transient engine operation is a challenging task since small fluctuations in EGR may cause larger than acceptable spikes in NOx/soot emissions or deterioration in the combustion efficiency. Moreover, the intake charge dilution at any EGR ratio is a function of engine load and intake pressure, and typically changes during transient events. Therefore, the management of EGR during transient engine operation or advanced combustion cycles (that are inherently less stable) requires a fundamental understanding of the transient EGR behaviour and its impact on the intake charge development. In this work, a zero-dimensional EGR model is described to estimate the transient (cycle-by-cycle) progression of EGR and the time (engine cycles) required for its stabilization. The model response is tuned to a multi-cylinder engine by using an overall engine system time-constant and shown to effectively track the transient EGR changes. The impact of EGR on the actual air–fuel ratio of the cylinder charge is quantified by defining an in-cylinder excess-air ratio that accounts for the oxygen in the recycled exhaust gas. Furthermore, a twin lambda sensor (TLS) technique is implemented for tracking the intake dilution and in-cylinder excess-air ratio in real-time. The modelling and analysis results are validated against a wide range of engine operations, including transient and steady-state low temperature combustion tests

  5. Feasibility study for a recirculating linac-based facility for femtosecond dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barry, W.; Barletta, W.A.; Byrd, J.M.; DeSantis, S.; Doolittle, L.; Fawley, W.; Green, M.A.; Hartman, N.; Heimann, P.; Kairan, D.; Kujawski, E.; Li, D.; Lidia, S.; Luft, P.; McClure, R.; Parmigiani, F.; Petroff, Y.; Pirkl, W.; Placidi, M.; Reavill, D.; Reichel, I.; Rimmer, R.A.; Ratti, A.; Robinson, K.E.; Sannibale, F.; Schoenlein, R.; Staples, J.; Tanabe, J.; Truchlikova, D.; Wan, W.; Wang, S.; Wells, R.; Wolski, A.; Zholents, A.

    2002-12-21

    LBNL is pursuing design studies and the scientific program for a facility dedicated to the production of x-ray pulses with ultra-short time duration, for application in dynamical studies of processes in physics, biology, and chemistry. The proposed x-ray facility has the short x-ray pulse length ({approx}60 fs FWHM) necessary to study very fast dynamics, high flux (up to approximately 10E11 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-12 keV photon energy. The hard x-ray photon production section of the machine accommodates seven 2-m long undulators. Design studies for longer wavelength sources, using high-gain harmonic generation, are in progress. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typically have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses uses relatively long electron bunches to minimize high-peak-current collective effects, and the ultimate x-ray duration is achieved by a combination of bunch manipulation and optical compression. Synchronization of x-ray pulses to sample excitation signals is expected to be of order 50 - 100 fs. Techniques for making use of the recirculating geometry to provide beam-based signals from early passes through the machine are being studied.

  6. Feasibility study for a recirculating linac-based facility for femtosecond dynamics

    International Nuclear Information System (INIS)

    Corlett, J.N.; Barry, W.; Barletta, W.A.; Byrd, J.M.; DeSantis, S.; Doolittle, L.; Fawley, W.; Green, M.A.; Hartman, N.; Heimann, P.; Kairan, D.; Kujawski, E.; Li, D.; Lidia, S.; Luft, P.; McClure, R.; Parmigiani, F.; Petroff, Y.; Pirkl, W.; Placidi, M.; Reavill, D.; Reichel, I.; Rimmer, R.A.; Ratti, A.; Robinson, K.E.; Sannibale, F.; Schoenlein, R.; Staples, J.; Tanabe, J.; Truchlikova, D.; Wan, W.; Wang, S.; Wells, R.; Wolski, A.; Zholents, A.

    2002-01-01

    LBNL is pursuing design studies and the scientific program for a facility dedicated to the production of x-ray pulses with ultra-short time duration, for application in dynamical studies of processes in physics, biology, and chemistry. The proposed x-ray facility has the short x-ray pulse length (∼60 fs FWHM) necessary to study very fast dynamics, high flux (up to approximately 10E11 photons/sec/0.1 percentBW) to study weakly scattering systems, and tuneability over 1-12 keV photon energy. The hard x-ray photon production section of the machine accommodates seven 2-m long undulators. Design studies for longer wavelength sources, using high-gain harmonic generation, are in progress. The x-ray pulse repetition rate of 10 kHz is matched to studies of dynamical processes (initiated by ultra-short laser pulses) that typically have a long recovery time or are not generally cyclic or reversible and need time to allow relaxation, replacement, or flow of the sample. The technique for producing ultra-short x-ray pulses uses relatively long electron bunches to minimize high-peak-current collective effects, and the ultimate x-ray duration is achieved by a combination of bunch manipulation and optical compression. Synchronization of x-ray pulses to sample excitation signals is expected to be of order 50 - 100 fs. Techniques for making use of the recirculating geometry to provide beam-based signals from early passes through the machine are being studied

  7. Seasonal occurrence of diseases in a recirculation system for salmonid fish in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Miroslava Palíková

    2014-01-01

    Full Text Available Aquaculture represents the fastest growing animal husbandry in many countries. However, higher intensity of fish farming can pose higher health hazards, too. We monitored the health status of fish from one fish farm in South Bohemia and discovered the main health problems in the breeding. For two years we examined a total of 224 specimens of brook trout (Salvelinus fontinalis, 126 specimens of hybrids (S. fontinalis × S. alpinus, 49 specimens of rainbow trout (Oncorhynchus mykiss – all clinically healthy, and 100 clinically diseased or freshly dead fish. We registered skin erosions mainly in the caudal peduncle and tail fin. Two parasite species were identified (one protist Ichthyophthirius multifiliis and one nematode Raphidascaris acus by parasitological examination. The epidemiological indicators of I. multifiliis were low. The prevalence of adult R. acus was 0–86% with a maximum in June. From November, capsules with larval stages of R. acus appeared in internal organs. Their highest intensity (200 pieces and prevalence (100% were detected in October. By microbiological examination of skin and gills, we identified changes in the density of bacterial population and its species composition dependent on water temperature and fish density. The most important problem on the monitored fish farm seems to be furunculosis of salmonid fish in all clinical forms, and the high intensity of larval stages of R. acus. The originality of this study is based on the fact that the observed breeding employs the first Danish recirculation system in the Czech Republic and no recent information about health problems has been available.

  8. Thermal tests of large recirculation cooling installations for nuclear power plants

    Science.gov (United States)

    Balunov, B. F.; Lychakov, V. D.; Il'in, V. A.; Shcheglov, A. A.; Maslov, O. P.; Rasskazova, N. A.; Rakhimov, R. Z.; Boyarov, R. A.

    2017-11-01

    The article presents the results from thermal tests of some recirculation installations for cooling air in nuclear power plant premises, including the volume under the containment. The cooling effect in such installations is produced by pumping water through their heat-transfer tubes. Air from the cooled room is blown by a fan through a bundle of transversely finned tubes and is removed to the same room after having been cooled. The finning of tubes used in the tested installations was made of Grade 08Kh18N10T and Grade 08Kh18N10 stainless steels or Grade AD1 aluminum. Steel fins were attached to the tube over their entire length by means of high-frequency welding. Aluminum fins were extruded on a lathe from the external tube sheath into which a steel tube had preliminarily been placed. Although the fin extrusion operation was accompanied by pressing the sheath inner part to the steel tube, tight contact between them over the entire surface was not fully achieved. In view of this, the air gap's thermal resistance coefficient was introduced in calculating the heat transfer between the heat-transferring media. The air gap average thickness was determined from the test results taking into account the gap variation with temperature due to different linear expansion coefficients of steel and aluminum. These tests, which are part of the acceptance tests of the considered installations, were carried out at the NPO TsKTI test facility and were mainly aimed at checking if the obtained thermal characteristics were consistent with the values calculated according to the standard recommendations with introduction, if necessary, of modifications to those recommendations.

  9. Ozonation control and effects of ozone on water quality in recirculating aquaculture systems.

    Science.gov (United States)

    Spiliotopoulou, Aikaterini; Rojas-Tirado, Paula; Chhetri, Ravi K; Kaarsholm, Kamilla M S; Martin, Richard; Pedersen, Per B; Pedersen, Lars-Flemming; Andersen, Henrik R

    2018-04-15

    To address the undesired effect of chemotherapeutants in aquaculture, ozone has been suggested as an alternative to improve water quality. To ensure safe and robust treatment, it is vital to define the ozone demand and ozone kinetics of the specific water matrix to avoid ozone overdose. Different ozone dosages were applied to water in freshwater recirculating aquaculture systems (RAS). Experiments were performed to investigate ozone kinetics and demand, and to evaluate the effects on the water quality, particularly in relation to fluorescent organic matter. This study aimed at predicting a suitable ozone dosage for water treatment based on daily ozone demand via laboratory studies. These ozone dosages will be eventually applied and maintained at these levels in pilot-scale RAS to verify predictions. Selected water quality parameters were measured, including natural fluorescence and organic compound concentration changes during ozonation. Ozone reactions were described by first order kinetics. Organic matter, assessed as chemical oxygen demand and fluorescence, decreased by 25% (low O 3 ), 30% (middle O 3 ) and 53% (high O 3 ), while water transmittance improved by 15% over an 8-day period. No fish mortality was observed. Overall, this study confirms that ozone can improve RAS water quality, provides a better understanding of the ozone decay mechanisms that can be used to define further safe ozone treatment margins, and that fluorescence could be used as a monitoring tool to control ozone. This study might be used as a tool to design ozone systems for full-scale RAS by analysing water sample from the specific RAS in the laboratory. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. An implantable centrifugal blood pump with a recirculating purge system (Cool-Seal system).

    Science.gov (United States)

    Yamazaki, K; Litwak, P; Tagusari, O; Mori, T; Kono, K; Kameneva, M; Watach, M; Gordon, L; Miyagishima, M; Tomioka, J; Umezu, M; Outa, E; Antaki, J F; Kormos, R L; Koyanagi, H; Griffith, B P

    1998-06-01

    A compact centrifugal blood pump has been developed as an implantable left ventricular assist system. The impeller diameter is 40 mm, and pump dimensions are 55 x 64 mm. This first prototype, fabricated from titanium alloy, resulted in a pump weight of 400 g including a brushless DC motor. The weight of a second prototype pump was reduced to 280 g. The entire blood contacting surface is coated with diamond like carbon (DLC) to improve blood compatibility. Flow rates of over 7 L/min against 100 mm Hg pressure at 2,500 rpm with 9 W total power consumption have been measured. A newly designed mechanical seal with a recirculating purge system (Cool-Seal) is used for the shaft seal. In this seal system, the seal temperature is kept under 40 degrees C to prevent heat denaturation of blood proteins. Purge fluid also cools the pump motor coil and journal bearing. Purge fluid is continuously purified and sterilized by an ultrafiltration unit which is incorporated in the paracorporeal drive console. In vitro experiments with bovine blood demonstrated an acceptably low hemolysis rate (normalized index of hemolysis = 0.005 +/- 0.002 g/100 L). In vivo experiments are currently ongoing using calves. Via left thoracotomy, left ventricular (LV) apex descending aorta bypass was performed utilizing an expanded polytetrafluoroethylene (ePTFE) vascular graft with the pump placed in the left thoracic cavity. In 2 in vivo experiments, the pump flow rate was maintained at 5-9 L/min, and pump power consumption remained stable at 9-10 W. All plasma free Hb levels were measured at less than 15 mg/dl. The seal system has demonstrated good seal capability with negligible purge fluid consumption (<0.5 ml/day). In both calves, the pumps demonstrated trouble free continuous function over 6 month (200 days and 222 days).

  11. Effect of cooling the recirculated exhaust gases on diesel engine emissions

    International Nuclear Information System (INIS)

    Abu-Hamdeh, Nidal H.

    2003-01-01

    Although combustion is essential in most energy generation processes, it is one of the major causes of air pollution. Spiral fin exhaust pipes were designed to study the effect of cooling the recirculated exhaust gases (EGR) of Diesel engines on the chemical composition of the exhaust gases and the reduction in the percentages of pollutant emissions. The gases examined in this study were oxides of nitrogen (NO x ), carbon dioxide (CO 2 ) and carbon monoxide (CO). In addition, O 2 concentration in the exhaust was measured. The two designs adopted in this study were exhaust pipes with solid and hollow fins around them. The first type uses air flow around the fins to cool the exhaust gases. The second type consists of hollow fins around the exhaust pipe to allow cooling water to flow in the hollow passage. Different combinations and arrangements of the solid and hollow fins exhaust pipes were used. It was found that decreasing the temperature of the EGR resulted in reductions in the oxides of nitrogen (NO x ) and carbon dioxide (CO 2 ) but increased the carbon monoxide (CO) in the exhaust gases. In addition, the oxygen (O 2 ) concentration in the exhaust was decreased. As a general trend, the percentages of reduction in the NO x gas concentrations were lower than the percentages of increase in the CO emissions as a result of cooling the EGR of a Diesel engine by a heat exchanger. Using water as a cooling medium decreased the exhaust gases temperature and the amount of pollutants more than did air as a cooling medium. In a separate series of tests, increasing the cooled EGR ratios decreased the exhaust NO x but increased the particulate matter concentrations in the exhaust gases

  12. Closed Circuit Videoinstallationen

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    be seen with only insignificant qualification as a specific characteristic of the medium. The closed-circuit video installations based on it represent the attest field of experiment for the assumptions on art and the theory and history of the medium that it might lead one make. In recent years...

  13. Review: The Closing Circle

    Science.gov (United States)

    Environment, 1972

    1972-01-01

    Two views of prominent biologists are presented side-by-side. Focal point is Barry Commoner's book, The Closing Circle, with a subsequent review by Paul Ehrlich. Growth of population, increases in affluence, and increased pollution from products of technology are considered. (BL)

  14. 'Closed Circuit' Anaesthesia

    African Journals Online (AJOL)

    The advantages of using rebreathing circuits in anaes- thesia are discussed and the principles for their correct employment are outlined. Practical methods are described. By using closed circuit equipment in the manner described, the initial cost of the apparatus could be recouped within one year, because of the saving in ...

  15. Resolving conflicting safety cultures

    International Nuclear Information System (INIS)

    Slider, J.E.; Patterson, M.

    1993-01-01

    Several nuclear power plant sites have been wounded in the crossfire between two distinct corporate cultures. The traditional utility culture lies on one side and that of the nuclear navy on the other. The two corporate cultures lead to different perceptions of open-quotes safety culture.close quotes This clash of safety cultures obscures a very important point about nuclear plant operations: Safety depends on organizational learning. Organizational learning provides the foundation for a perception of safety culture that transcends the conflict between utility and nuclear navy cultures. Corporate culture may be defined as the knowledge, attitudes, and beliefs shared by employees of a given company. Safety culture is the part of corporate culture concerning shared attitudes and beliefs affecting individual or public safety. If the safety culture promotes behaviors that lead to greater safety, employees will tend to open-quotes do the right thingclose quotes even when circumstances and formal guidance alone do not ensure that actions will be correct. Safety culture has become particularly important to nuclear plant owners and regulators as they have sought to establish and maintain a high level of safety in today's plants

  16. Fecal culture

    Science.gov (United States)

    ... parasites exam Alternative Names Stool culture; Culture - stool; Gastroenteritis fecal culture Images Salmonella typhi organism Yersinia enterocolitica organism Campylobacter jejuni organism Clostridium difficile organism References Beavis, KG, ...

  17. Closing the loop.

    Science.gov (United States)

    Dassau, E; Atlas, E; Phillip, M

    2010-02-01

    The dream of closing the loop is actually the dream of creating an artificial pancreas and freeing the patients from being involved with the care of their own diabetes. Insulin-dependent diabetes (type 1) is a chronic incurable disease which requires constant therapy without the possibility of any 'holidays' or insulin-free days. It means that patients have to inject insulin every day of their life, several times per day, and in order to do it safely they also have to measure their blood glucose levels several times per day. Patients need to plan their meals, their physical activities and their insulin regime - there is only very small room for spontaneous activities. This is why the desire for an artificial pancreas is so strong despite the fact that it will not cure the diabetic patients. Attempts to develop a closed-loop system started in the 1960s but never got to a clinical practical stage of development. In recent years the availability of continuous glucose sensors revived those efforts and stimulated the clinician and researchers to believe that closing the loop might be possible nowadays. Many papers have been published over the years describing several different ideas on how to close the loop. Most of the suggested systems have a sensing arm that measures the blood glucose repeatedly or continuously, an insulin delivery arm that injects insulin upon command and a computer that makes the decisions of when and how much insulin to deliver. The differences between the various published systems in the literature are mainly in their control algorithms. However, there are also differences related to the method and site of glucose measurement and insulin delivery. SC glucose measurements and insulin delivery are the most studied option but other combinations of insulin measurements and glucose delivery including intravascular and intraperitoneal (IP) are explored. We tried to select recent publications that we believe had influenced and inspired people interested

  18. Hydraulic retention time impact of treated recirculated leachate on the hydrolytic kinetic rate of coffee pulp in an acidogenic reactor.

    Science.gov (United States)

    Houbron, E; González-López, G I; Cano-Lozano, V; Rustrían, E

    2008-01-01

    This study attempted to investigate the impact of HRT of treated leachate recirculation on hydrolysis solubilization rate of coffee pulp in an acidogenic reactor. Coffee pulp presents more than 70% of organic matter and around of 30% of lignin and cellulose. Five lab scale reactors of 20 litres were used. Each reactor was fed with 5 kg of fresh coffee pulp and anaerobic sludge was used as inoculate. HRT of 0.5, 1, 3 and 10 days were applied. Each experiment shows that Total, Soluble and VFA COD appear rapidly in the removed leachate. HRT have a great impact on hydrolytic rate with an optimal value of 32,000 mg x L(-1) x d(-1).Low HRT increases hydrolysis rate and in consequence reduces duration of the hydrolytic phase. Also composition and concentration of VFA are influenced by HRT. Low ones favour acetic acid production and high ones permit the production of butyric. Low HRT generates leachate more easily fermentable. Efficiency of solubilization and acidification are independent of the HRT and present average values of 78% and 65% respectively. By batch feeding solid and continuous recirculation of treated leachate, HRT and SRT could be dissociated, where solid had a very high retention without problems of load, mixing and inhibition, and liquid could be recirculated with a very high rate. Under these low HRT condition, the first reactor of a two stage anaerobic system could reduces the hydrolysis duration of organic solid waste like coffee pulp and generate an optimal leachate for the methanization process. Copyright IWA Publishing 2008.

  19. Reaction phenomena of catalytic partial oxidation of methane under the impact of carbon dioxide addition and heat recirculation

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Lin, Shih-Cheng

    2015-01-01

    The reaction phenomena of CPOM (catalytic partial oxidation of methane) in a Swiss-roll reactor are studied numerically where a rhodium-based catalyst bed is embedded at the center of the reactor. CO 2 is added into the feed gas and excess enthalpy recovery is performed to evaluate their influences on CPOM performance. In the study, the mole ratio of O 2 to CH 4 (O 2 /CH 4 ratio) is fixed at 0.5 and the mole ratio of CO 2 to O 2 (CO 2 /O 2 ratio) is in the range of 0–2. The results reveal that CO 2 addition into the influent has a slight effect on methane combustion, but significantly enhances dry reforming and suppresses steam reforming. The reaction extents of steam reforming and dry reforming in CPOM without heat recovery and CO 2 addition are in a comparable state. Once CO 2 is added into the feed gas, the dry reforming is enhanced, thereby dominating CH 4 consumption. Compared to the reactor without excess enthalpy recovery, heat recirculation drastically increases the maximum reaction temperature and CH 4 conversion in the catalyst bed; it also intensifies the H 2 selectivity, H 2 yield, CO 2 conversion, and syngas production rate. The predictions indicate that the heat recirculation is able to improve the syngas formation up to 45%. - Highlights: • Catalytic partial oxidation of methane with CO 2 addition and heat recovery is studied. • CO 2 addition has a slight effect on methane combustion. • CO 2 addition significantly enhances dry reforming and suppresses steam reforming. • Dry reforming dominates CH 4 consumption when CO 2 addition is large. • Heat recirculation can improve the syngas formation up to 45%

  20. Mean shear flow in recirculating turbulent urban convection and the plume-puff eddy structure below stably stratified inversion layers

    Science.gov (United States)

    Fan, Yifan; Hunt, Julian; Yin, Shi; Li, Yuguo

    2018-03-01

    The mean and random components of the velocity field at very low wind speeds in a convective boundary layer (CBL) over a wide urban area are dominated by large eddy structures—either turbulent plumes or puffs. In the mixed layer at either side of the edges of urban areas, local mean recirculating flows are generated by sharp horizontal temperature gradients. These recirculation regions also control the mean shear profile and the bent-over plumes across the mixed layer, extending from the edge to the center of the urban area. A simplified physical model was proposed to calculate the mean flow speed at the edges of urban areas. Water tank experiments were carried out to study the mean recirculating flow and turbulent plume structures. The mean speed at urban edges was measured by the particle image velocimetry (PIV), and the plume structures were visualized by the thermalchromic liquid crystal (TLC) sheets. The horizontal velocity calculated by the physical model at the urban edge agrees well with that measured in the water tank experiments, with a root mean square of 0.03. The experiments also show that the pattern of the mean flow over the urban area changes significantly if the shape of the heated area changes or if the form of the heated urban area becomes sub-divided, for example by the creation of nearby but separated "satellite cities." The convective flow over the square urban area is characterized as the diagonal inflow at the lower level and the side outflow at the upper level. The outflow of the small city can be drawn into the inflow region of the large city in the "satellite city" case. A conceptual analysis shows how these changes significantly affect the patterns of dispersion of pollutants in different types of urban areas.

  1. Molecular Adsorbent Recirculating System Can Reduce Short-Term Mortality Among Patients With Acute-on-Chronic Liver Failure-A Retrospective Analysis.

    Science.gov (United States)

    Gerth, Hans U; Pohlen, Michele; Thölking, Gerold; Pavenstädt, Hermann; Brand, Marcus; Hüsing-Kabar, Anna; Wilms, Christian; Maschmeier, Miriam; Kabar, Iyad; Torner, Josep; Pavesi, Marco; Arroyo, Vicente; Banares, Rafael; Schmidt, Hartmut H J

    2017-10-01

    Acute-on-chronic liver failure is associated with numerous consecutive organ failures and a high short-term mortality rate. Molecular adsorbent recirculating system therapy has demonstrated beneficial effects on the distinct symptoms, but the associated mortality data remain controversial. Retrospective analysis of acute-on-chronic liver failure patients receiving either standard medical treatment or standard medical treatment and molecular adsorbent recirculating system. Secondary analysis of data from the prospective randomized Recompensation of Exacerbated Liver Insufficiency with Hyperbilirubinemia and/or Encephalopathy and/or Renal Failure trial by applying the recently introduced Chronic Liver Failure-criteria. Medical Departments of University Hospital Muenster (Germany). This analysis was conducted in two parts. First, 101 patients with acute-on-chronic liver failure grades 1-3 and Chronic Liver Failure-C-Organ Failure liver subscore equals to 3 but stable pulmonary function were identified and received either standard medical treatment (standard medical treatment, n = 54) or standard medical treatment and molecular adsorbent recirculating system (n = 47) at the University Hospital Muenster. Second, the results of this retrospective analysis were tested against the Recompensation of Exacerbated Liver Insufficiency with Hyperbilirubinemia and/or Encephalopathy and/or Renal Failure trial. Standard medical treatment and molecular adsorbent recirculating system. Additionally to improved laboratory variables (bilirubin and creatinine), the short-term mortality (up to day 14) of the molecular adsorbent recirculating system group was significantly reduced compared with standard medical treatment. A reduced 14-day mortality rate was observed in the molecular adsorbent recirculating system group (9.5% vs 50.0% with standard medical treatment; p = 0.004), especially in patients with multiple organ failure (acute-on-chronic liver failure grade 2-3). Concerning the

  2. Environmental impact assessment of leachate recirculation in landfill of municipal solid waste by comparing with evaporation and discharge (EASEWASTE).

    Science.gov (United States)

    Xing, Wei; Lu, Wenjing; Zhao, Yan; Zhang, Xu; Deng, Wenjing; Christensen, Thomas H

    2013-02-01

    In some arid regions where landfill produces minimal amount of leachate, leachate recirculation is suggested as a cost-effective option. However, its long-term impacts to environment remain disputed. For the purpose of revealing the environmental impacts of leachate recirculation in landfill, four scenarios were modeled using EASEWASTE, comparing the strategies of leachate recirculation (with or without gas management), evaporation and discharge. In the current situation (Scenario A), a total of 280 t of waste was generated and then transported to a conventional landfill for disposal. A number of contaminants derived from waste can be stored in the landfill for long periods, with 11.69 person equivalent (PE) for stored ecotoxicity in water and 29.62 PE for stored ecotoxicity in soil, considered as potential risks of releasing to the environment someday. Meanwhile, impacts to ecotoxicity and human toxicity in surface water, and those to groundwater, present relatively low levels. In Scenario B, leachate evaporation in a collecting pool has minimal impacts on surface water. However, this strategy significantly impacts groundwater (1055.16 PE) because of the potential infiltration of leachate, with major contaminants of As, ammonia, and Cd. A number of ions, such as Cl(-), Mg(2+), and Ca(2+), may also contaminate groundwater. In Scenario C, the direct discharge of leachate to surface water may result in acidification (2.71 PE) and nutrient enrichment (2.88 PE), primarily attributed to soluble ammonia in leachate and the depositional ammonia from biogas. Moreover, the direct discharge of leachate may also result in ecotoxicity and human toxicity via water contaminated by heavy metals in leachate, with 3.96 PE and 11.64 PE respectively. The results also show that landfill gas is the main contributor to global warming and photochemical ozone formation due to methane emission. In Scenario D, landfill gas flaring was thus be modeled and proven to be efficient for reducing

  3. C2R2. Compact Compound Recirculator/Recuperator for Renewable Energy and Energy Efficient Thermochemical Processing.

    Energy Technology Data Exchange (ETDEWEB)

    Ermanoski, Ivan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Orozco, Adrian [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    In this report we present the development of a packed particle bed recirculator and heat exchanger. The device is intended to create countercurrent flows of packed particle beds and exchange heat between the flows. The project focused on the design, fabrication, demonstration, and modifications of a simple prototype, in order to attain high levels of heat exchange between particle flows while maintaining an effective particle conveying rate in a scalable package. Despite heat losses in a package not optimized for heat retention, 50% heat recovery was achieved, at a particle conveying efficiency of 40%.

  4. Monte Carlo simulations on particle loss in the recirculation phase of the COSY cooler synchrotron, and consequences for radiation protection

    International Nuclear Information System (INIS)

    Steger, U.

    1990-01-01

    The paper shows that particle losses can be concentrated in very limited areas by inserting orifices at appropriate positions in the ring. Consequences for shielding measures are discussed.The considerations and calculations were made for the cooler synchroton COSY under construction at the Juelich research center. It consists of an accelerator and storage ring for light particles, in particular protons, with a maximum energy of ∼ 2.5 GeV. From the large number of possible working positions, a suitable one for the recirculation phase with a target at place TP2 was chosen. Orifice and shielding optimization was dealt with exemplarily. (orig.) [de

  5. System and method for regeneration and recirculation of a reducing agent using highly exothermic reactions induced by mixed industrial slags

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, Jinichiro; Bennett, James P.; Nakano, Anna

    2017-12-12

    Embodiments relate to systems and methods for regenerating and recirculating a CO, H.sub.2 or combinations thereof utilized for metal oxide reduction in a reduction furnace. The reduction furnace receives the reducing agent, reduces the metal oxide, and generates an exhaust of the oxidized product. The oxidized product is transferred to a mixing vessel, where the oxidized product, a calcium oxide, and a vanadium oxide interact to regenerate the reducing agent from the oxidized product. The regenerated reducing agent is transferred back to the reduction furnace for continued metal oxide reductions.

  6. Sustainable Zero-Valent Metal (ZVM Water Treatment Associated with Diffusion, Infiltration, Abstraction, and Recirculation

    Directory of Open Access Journals (Sweden)

    David D.J. Antia

    2010-09-01

    Full Text Available Socio-economic, climate and agricultural stress on water resources have resulted in increased global demand for water while at the same time the proportion of potential water resources which are adversely affected by sodification/salinisation, metals, nitrates, and organic chemicals has increased. Nano-zero-valent metal (n-ZVM injection or placement in aquifers offers a potential partial solution. However, n-ZVM application results in a substantial reduction in aquifer permeability, which in turn can reduce the amount of water that can be abstracted from the aquifer. This study using static diffusion and continuous flow reactors containing n-ZVM and m-ZVM (ZVM filaments, filings and punchings has established that the use of m-ZVM does not result in a reduction in aquifer permeability. The experimental results are used to design and model m-ZVM treatment programs for an aquifer (using recirculation or static diffusion. They also provide a predictive model for water quality associated with specific abstraction rates and infiltration/injection into an aquifer. The study demonstrates that m-ZVM treatment requires 1% of the weight required for n-ZVM treatment for a specific flow rate. It is observed that 1 t Fe0 will process 23,500 m3 of abstracted or infiltrating water. m-ZVM is able to remove >80% of nitrates from flowing water and adjust the water composition (by reduction in an aquifer to optimize removal of nitrates, metals and organic compounds. The experiments demonstrate that ZVM treatment of an aquifer can be used to reduce groundwater salinity by 20 –> 45% and that an aquifer remediation program can be designed to desalinate an aquifer. Modeling indicates that widespread application of m-ZVM water treatment may reduce global socio-economic, climate and agricultural stress on water resources. The rate of oxygen formation during water reduction [by ZVM (Fe0, Al0 and Cu0] controls aquifer permeability, the associated aquifer pH, aquifer Eh

  7. Preformulation investigation and challenges; salt formation, salt disproportionation and hepatic recirculation.

    Science.gov (United States)

    Sigfridsson, Kalle; Nilsson, Lena; Ahlqvist, Matti; Andersson, Thomas; Granath, Anna-Karin

    2017-06-15

    A compound, which is a selective peroxisome proliferator activated receptor (PPAR) agonist, was investigated. The aim of the presented studies was to evaluate the potential of the further development of the compound. Fundamental physicochemical properties and stability of the compound were characterized in solution by liquid chromatography and NMR and in solid-state by various techniques. The drug itself is a lipophilic acid with tendency to form aggregates in solution. The neutral form was only obtained in amorphous form with a glass-transition temperature of approximately 0°C. The intrinsic solubility at room temperature was determined to 0.03mg/mL. Chemical stability studies of the compound in aqueous solutions showed good stability for at least two weeks at room temperature, except at pH1, where a slight degradation was already observed after one day. The chemical stability in the amorphous solid-state was investigated during a period of three months. At 25°C/60% relative humidity (RH) and 40°C/75% RH no significant degradation was observed. At 80°C, however, some degradation was observed after four weeks and approximately 3% after three months. In an accelerated photostability study, degradation of approximately 4% was observed. Attempts to identify a crystalline form of the neutral compound were unsuccessful, however, salt formation with tert-butylamine, resulted in crystalline material. Results from stability tests of the presented crystalline salt form indicated improved chemical stability at conditions whereas the amorphous neutral form degraded. However, the salt form of the drug dissociated under certain conditions. The drug was administered both per oral and intravenously, as amorphous nanoparticles, to conscious dogs. Plasma profiles showed curves with secondary absorption peaks, indicating hepatic recirculation following both administration routes. A similar behavior was observed in rats after oral administration of a pH-adjusted solution. The

  8. Nitrous oxide emissions from near-zero water exchange brackish recirculating aquaculture systems.

    Science.gov (United States)

    Yogev, Uri; Atari, Adiel; Gross, Amit

    2018-02-14

    The development of intensive recirculating aquaculture systems (RAS) with low water exchange has accelerated in recent years as a result of environmental, economic and other concerns. In these systems, fish are commonly grown at high density, 50 to 150kg/m 3 , using high-protein (30%-60%) feeds. Typically, the RAS consists of a solid treatment and a nitrification unit; in more advanced RAS, there is an additional denitrification step. Nitrous oxide (N 2 O), a byproduct during nitrification and denitrification processes, is a potent greenhouse gas that destroys the ozone layer. The aim of this study was to measure and assess N 2 O emissions from a near-zero discharge land-based saline RAS. N 2 O flux was monitored from the RAS's fish tank, and moving-bed nitrification and activated-sludge (with intrinsic C source) denitrification reactors. N 2 O emission potential was also analyzed in the laboratory. N 2 O flux from the denitrification reactors ranged between 6.5 and 48mg/day, equivalent to 1.27±1.01% of the removed nitrate-N. Direct analysis from the fish tank and nitrification reactors could not be performed due to high aeration, which diluted the N 2 O concentration to below detection limits. Thus, its potential emission was estimated in the laboratory: from the fishponds, it was negligible; from the nitrification reactor, it ranged between 0.4 and 2.8% of the total ammonia-N oxidized. The potential N 2 O emission from the denitrification reactor was 3.72±2.75% of the reduced nitrate-N, within the range found in the direct measurement. Overall, N 2 O emission during N transformation in a RAS was evaluated to be 885mg/kg feed or 1.36g/kg fish production, accounting for 1.23% of total N application. Consequently, it is estimated that N 2 O emission from aquaculture currently accounts for 2.4% of the total agricultural N 2 O emission, but will decrease to 1.7% by 2030. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Emission characteristics of iso-propanol/gasoline blends in a spark-ignition engine combined with exhaust gas re-circulation

    Directory of Open Access Journals (Sweden)

    Gong Jing

    2014-01-01

    Full Text Available Experiments were carried out in a spark-ignition engine fueled with iso-propanol/gasoline blends. Emission characteristics of this engine were investigated experimentally, including gaseous emissions (HC, CO, NOx and particulate matter emission in term of number and size distributions. The effects of different iso-propanol percentages, loads and exhaust gas recirculation rates on emissions were analyzed. Results show that the introduction of exhaust gas recirculation reduces the NOx emission and NOx emission gives the highest value at full load condition. HC and CO emissions present inconspicuous variations at all the loads except the load of 10%. Additionally, HC emission shows a sharp increase for pure propanol when the exhaust gas recirculation rate is up to 5%, while little variation is observed at lager exhaust gas recirculation rates. Moreover, the particulate matter number concentration increases monotonically with the increase of load and the decrease of exhaust gas recirculation rate. There exists a critical spark timing that produces the highest particulate matter number concentration at all the blending ratios.

  10. Openings and Closings in Telephone Conversations between Native Spanish Speakers.

    Science.gov (United States)

    Coronel-Molina, Serafin M.

    1998-01-01

    A study analyzed the opening and closing sequences of 11 dyads of native Spanish-speakers in natural telephone conversations conducted in Spanish. The objective was to determine how closely Hispanic cultural patterns of conduct for telephone conversations follow the sequences outlined in previous research. It is concluded that Spanish…

  11. Closing the gasoline system

    International Nuclear Information System (INIS)

    Hutcheson, R.C.

    1992-01-01

    In this paper, a representative of the Oil Companies' European Organization for Environmental and Health Protection (CONCAWE), argues the advantages of closing the gasoline system. Because this decouples the product from the environment, health risks and environmental damage are reduced. It is also more effective than changing the composition of gasoline because it offers better cost effectiveness, energy efficiency and the minimization of carbon dioxide release into the environment. However it will take time and political will to change until all European vehicles are fitted with three way catalysts and carbon canisters: control systems to monitor such systems will also need to be set up. However CONCAWE still recommends its adoption. (UK)

  12. Far Away, So Close

    DEFF Research Database (Denmark)

    Jensen, Pia Majbritt

    2018-01-01

    With its small population of only 5.6 million inhabitants, its public service broadcasting dominance, and no recent history of world colonization or immigration, the near global success of Denmark’s television industry over the last five years is as unprecedented as it is impressive. Previous work...... on transnational media distribution and reception has repeatedly shown that non-Anglophone content rarely exports outside its geo-linguistic region due to the perception that audiences in other regions would be too far removed culturally and linguistically. Similarly, theories on the consumption of audio...

  13. Closed Strings From Nothing

    International Nuclear Information System (INIS)

    Lawrence, Albion

    2001-01-01

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order α' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting

  14. Closed Strings From Nothing

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, Albion

    2001-07-25

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order {alpha}' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting.

  15. Field evaluation of a horizontal well recirculation system for groundwater treatment: Pilot test at the Clean Test Site Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

    International Nuclear Information System (INIS)

    Muck, M.T.; Kearl, P.M.; Siegrist, R.L.

    1998-01-01

    This report presents the results of field testing a horizontal well recirculation system at the Portsmouth Gaseous Diffusion Plant (PORTS). The recirculation system uses a pair of horizontal wells, one for groundwater extraction and treatment and the other for reinjection of treated groundwater, to set up a recirculation flow field. The induced flow field from the injection well to the extraction well establishes a sweeping action for the removal and treatment of groundwater contaminants. The overall purpose of this project is to study treatment of mixed groundwater contaminants that occur in a thin water-bearing zone not easily targeted by traditional vertical wells. The project involves several research elements, including treatment-process evaluation, hydrodynamic flow and transport modeling, pilot testing at an uncontaminated site, and pilot testing at a contaminated site. The results of the pilot test at an uncontaminated site, the Clean Test Site (CTS), are presented in this report

  16. Application of the Na+ recirculation theory to ion coupled water transport in low- and high resistance osmoregulatory epithelia.

    Science.gov (United States)

    Larsen, Erik Hviid; Møbjerg, Nadja; Nielsen, Robert

    2007-09-01

    The theory of Na+ recirculation for isosmotic fluid absorption follows logically from Hertz's convection-diffusion equation applied to the exit of water and solutes from the lateral intercellular space. Experimental evidence is discussed indicating Na+ recirculation based upon the following approaches: (i) An isotope tracer method in small intestine. Simultaneous measurement of water flow and ion transport in toad skin epithelium demonstrating, (ii) occasional hyposmotic absorbates, and (iii) reduced fluid absorption in the presence of serosal bumetanide. (iv) Studies of the metabolic cost of net Na+ absorption demonstrating an efficiency that is lower than the 18 Na+ per O2 consumed given by the stoichiometry of the Na+/K+-pump. Mathematical modeling predicts a significant range of observations such as isosmotic transport, hyposmotic transport, solvent drag, anomalous solvent drag, the residual hydraulic permeability in proximal tubule of AQP1(-/-) mice, the adverse relationship between hydraulic permeability and the concentration difference needed to reverse transepithelial water flow, and in a non-contradictory way the wide range of metabolic efficiencies from above to below 18 Na+/O2. Certain types of observations are poorly or not at all reproduced by the model. It is discussed that such lack of agreement between model and experiment is due to cellular regulations of ion permeabilities that are not incorporated in the modeling. Clarification of these problems requires further experimental studies.

  17. Optimization of two-phase thermophilic anaerobic digestion of biowaste for hydrogen and methane production through reject water recirculation.

    Science.gov (United States)

    Cavinato, C; Bolzonella, D; Fatone, F; Cecchi, F; Pavan, P

    2011-09-01

    The optimization of a two-phase thermophilic anaerobic process treating biowaste for hydrogen and methane production was carried out at pilot scale using two stirred reactors (CSTRs) and without any physical/chemical pre-treatment of inoculum. During the experiment the hydrogen production at low hydraulic retention time (3d) was tested, both with and without reject water recirculation and at two organic loading rate (16 and 21 kgTVS/m3 d). The better yields were obtained with recirculation where the pH reached an optimal value (5.5) thanks to the buffering capacity of the recycle stream. The specific gas production of the first reactor was 51 l/kgVS(fed) and H2 content in biogas 37%. The mixture of gas obtained from the two reactors met the standards for the biohythane mix only when lower loading rate were applied to the first reactor, with a composition of 6.7% H2, 40.1% CO2 and 52.3% CH4 the overall SGP being 0.78 m3/kgVS(fed). Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Biogas recirculation for simultaneous calcium removal and biogas purification within an expanded granular sludge bed system treating leachate.

    Science.gov (United States)

    Luo, Jinghuan; Lu, Xueqin; Liu, Jianyong; Qian, Guangren; Lu, Yongsheng

    2014-12-01

    Biogas, generated from an expanded granular sludge bed (EGSB) reactor treating municipal solid waste (MSW) leachate, was recirculated for calcium removal from the leachate via a carbonation process with simultaneous biogas purification. Batch trials were performed to optimize the solution pH and imported biogas (CO2) for CaCO3 precipitation. With applicable pH of 10-11 obtained, continuous trials achieved final calcium concentrations of 181-375 mg/L (removal efficiencies≈92.8-96.5%) in the leachate and methane contents of 87.1-91.4% (purification efficiencies≈65.4-82.2%) in the biogas. Calcium-balance study indicates that 23-986 mg Ca/d was released from the bio-system under the carbonized condition where CaCO3 precipitating was moved outside the bioreactor, whereas 7918-9517 mg Ca/d was trapped into the system for the controlled one. These findings demonstrate that carbonation removal of calcium by biogas recirculation could be a promising alternative to pretreat calcium-rich MSW leachate and synergistically to improve methane content. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Influence of alkalinity and VFAs on the performance of an UASB reactor with recirculation for the treatment of Tequila vinasses.

    Science.gov (United States)

    López-López, Alberto; León-Becerril, Elizabeth; Rosales-Contreras, María Elena; Villegas-García, Edgardo

    2015-01-01

    The main problem linked to the stability of upflow anaerobic sludge blanket (UASB) reactors during the treatment of Tequila vinasse is the high acidity and the null alkalinity present in this effluent. This research evaluates the effect of alkalinity and volatile fatty acids (VFAs) concentration on the performance of an UASB reactor with recirculation of the effluent for removing organic matter and biogas production from Tequila vinasses. Recirculation of the effluent reduces the impact of VFAs and organic matter concentration present in the influent, inducing the stability of the reactor. The UASB reactor was operated during 235 days at organic loading rates from 2.5 to 20.0 kg m(-3) d(-1), attaining a removal efficiency of COD greater than 75% with a methane yield of 335 ml CH4 g(-1) COD at SPT, maintaining a ratio of VFAs/Alk ≤ 0.5. Therefore, an optimal ratio of VFAs/Alk was established for the system operating in stable conditions for the treatment of Tequila vinasses. Under these conditions, the alkalinity was recuperated by the system itself, without the addition of external alkalinity.

  20. Effect of increasing salinity on biogas production in waste landfills with leachate recirculation: A lab-scale model study

    Directory of Open Access Journals (Sweden)

    Yuka Ogata

    2016-06-01

    Full Text Available The effects of salinity on anaerobic waste degradation and microbial communities were investigated, in order to propose an appropriate leachate recirculation process in a waste landfill in a tropical region. A salt concentration of 21 mS cm−1 of electrical conductivity (EC did not affect waste degradation, but a salt concentration of 35 mS cm−1 of EC inhibited CH4 generation. A higher salt concentration of 80 mS cm−1 of EC inhibited not only CH4 and CO2 generation, but also degradation of organic compounds. The bacterial and archaeal community compositions were affected by high salinity. High salinity can exert selective pressure on bacterial communities, resulting in a change in bacterial community structure. Ammonium caused strong, dominant inhibition of biogas production in the salt concentration range of this study. Quality control, especially of ammonium levels, will be essential for the promotion of waste biodegradation in landfills with leachate recirculation.

  1. Transport behavior of surrogate biological warfare agents in a simulated landfill: Effect of leachate recirculation and water infiltration

    KAUST Repository

    Saikaly, Pascal

    2010-11-15

    An understanding of the transport behavior of biological warfare (BW) agents in landfills is required to evaluate the suitability of landfills for the disposal of building decontamination residue (BDR) following a bioterrorist attack on a building. Surrogate BW agents, Bacillus atrophaeus spores and Serratia marcescens, were spiked into simulated landfill reactors that were filled with synthetic building debris (SBD) and operated for 4 months with leachate recirculation or water infiltration. Quantitative polymerase chain reaction (Q-PCR) was used to monitor surrogate transport. In the leachate recirculation reactors, <10% of spiked surrogates were eluted in leachate over 4 months. In contrast, 45% and 31% of spiked S. marcescens and B. atrophaeus spores were eluted in leachate in the water infiltration reactors. At the termination of the experiment, the number of retained cells and spores in SBD was measured over the depth of the reactor. Less than 3% of the total spiked S. marcescens cells and no B. atrophaeus spores were detected in SBD. These results suggest that significant fractions of the spiked surrogates were strongly attached to SBD. © 2010 American Chemical Society.

  2. Multiculturalisme et culture

    DEFF Research Database (Denmark)

    Landes, Xavier

    2011-01-01

    . On epistemological grounds, these approaches would assimilate cultures to closed ensembles with strictly defined contours and content. On political grounds, such a conception faces three types of objections. It would favor the propagation of stereotypes, influence the balance of power within communities and alter......This article engages the role played by culture in a part of multicultural literature. Through the study of Charles Taylor and Will Kymlicka's positions, it introduces to the critique of reductionism which is addressed to approaches founded on the intrinsic or instrumental value of culture...

  3. Translation as cultural mediator

    Directory of Open Access Journals (Sweden)

    Roxana Petcu

    2009-01-01

    Full Text Available The aim of this paper is to analyze the role that translation plays as cultural mediator, as it already widely accepted that translation involves not just two languages, but two cultures, two worlds that are brought into close contact with each other. Obviously, between the two cultures, the two worlds that translation compares and contrasts there are both similarities and dissimilarities. What is of interest to us is the way in which dissimilarities should be approached in the process of translation, whether they should be domesticated or foreignized as Venuti put it, whether the reader should be brought closer to the text or the text closer to the reader.

  4. Multiculturalisme et culture

    DEFF Research Database (Denmark)

    Landes, Xavier

    2011-01-01

    This article engages the role played by culture in a part of multicultural literature. Through the study of Charles Taylor and Will Kymlicka's positions, it introduces to the critique of reductionism which is addressed to approaches founded on the intrinsic or instrumental value of culture....... On epistemological grounds, these approaches would assimilate cultures to closed ensembles with strictly defined contours and content. On political grounds, such a conception faces three types of objections. It would favor the propagation of stereotypes, influence the balance of power within communities and alter...

  5. Closed loop reflux system

    International Nuclear Information System (INIS)

    De Witt, R.; Jepson, B.E.; Schwind, R.A.

    1975-01-01

    Sulfur isotopes are continuously separated and enriched using a closed loop reflux system wherein sulfur dioxide (SO 2 ) is reacted with sodium hydroxide (NaOH) or the like to form sodium hydrogen sulfite (NaHSO 3 ). Heavier sulfur isotopes are preferentially attracted to the NaHSO 3 , and subsequently reacted with sulfuric acid (H 2 SO 4 ) forming sodium hydrogen sulfate (NaHSO 4 ) and SO 2 gas, which contains increased concentrations of the heavier sulfur isotopes. This heavy isotope enriched SO 2 gas is subsequently separated and the NaHSO 4 is reacted with NaOH to form sodium sulfate (Na 2 SO 4 ), which is subsequently decomposed in an electrodialysis unit to form the NaOH and H 2 SO 4 components, which are used in the aforesaid reactions thereby effecting sulfur isotope separation and enrichment without objectionable loss of feed materials. (U.S.)

  6. Jealousy and Relationship Closeness

    Directory of Open Access Journals (Sweden)

    Mark Attridge

    2013-02-01

    Full Text Available This study confirmed a hypothesis from the Emotion-in-Relationships conceptual model, which predicts that greater interdependence between relationship partners—or closeness—creates the potential for jealousy. The study also sought to better define the positive side of romantic jealousy in addition to its more negative attributes. College students in premarital relationships (N = 229 completed a questionnaire, including 27 different measures and the Multidimensional Jealousy Scale. Select data were obtained from 122 cases at 3-month follow-up. Each jealousy scale was tested for associations with demographic (age, sex, and race, person (life satisfaction, loneliness, romantic attachment styles, love styles, and romantic beliefs, and relationship (affective, closeness, and social exchange theory constructs. Results clearly distinguished emotional/reactive jealousy as mostly “good” and cognitive/suspicious jealousy as “bad.” Behavioral jealousy was associated with few measures. Implications are discussed for the interdependence model of relationships and the transactional model of jealousy.

  7. Science policy up close

    CERN Document Server

    Marburger, John H

    2015-01-01

    In a career that included tenures as president of Stony Brook University, director of Brookhaven National Laboratory, and science advisor to President George W. Bush, John Marburger (1941 2011) found himself on the front line of battles that pulled science ever deeper into the political arena. From nuclear power to global warming and stem cell research, science controversies, he discovered, are never just about science. Science Policy Up Close" presents Marburger s reflections on the challenges science administrators face in the twenty-first century. In each phase of public service Marburger came into contact with a new dimension of science policy. The Shoreham Commission exposed him to the problem of handling a volatile public controversy over nuclear power. The Superconducting Super Collider episode gave him insights into the collision between government requirements and scientists expectations and feelings of entitlement. The Directorship of Brookhaven taught him how to talk to the public about the risks ...

  8. Need for clean water and recirculation to reduce emissions of plant protection products from soilless cultivation

    NARCIS (Netherlands)

    Vermeulen, T.; Os, van E.A.; Linden, van der A.M.A.; Wipfler, E.L.

    2017-01-01

    Soilless cultivation suggests a closed system of water flows, the principal of which are (drip) irrigation evaporation and - in more high-tech systems -condensation water. However, in practice growers discharge water during the process of filter cleaning and also actively discharge water due to

  9. Culture as Capital

    DEFF Research Database (Denmark)

    Kacunko, Slavko

    A collection of essays 2011-2014 By following, and reproducing, the cultural turn, the rhetoric of cultural mix and hybridism is disseminated today primarily in its crossing of trade barriers. Cultures reduced to their exchange value function as capital - an accumulative, speculative and...... essays, Slavko Kacunko discusses the process art by crossing the disciplines of art history and comparative media-, visual- and -cultural studies. As a first approximation, several historiographical remarks on closed-circuit video installations underline their importance as a core category of process art....... In the second part, the problems of process art, seen as a threshold of art history, are further examined in another retroanalytical step, in which concepts and objects related to `mirror', `frame' and `immediacy' are analyzed as the triple delimitation of visual culture studies. In the third part, previously...

  10. Plant Tissue Culture

    Indian Academy of Sciences (India)

    Admin

    closely linked with the discovery and characterization of plant hormones, and has facilitated our understanding of plant growth and development. Furthermore, the ability to grow plant cells and tissues in culture and to control their development forms the basis of many practical applications in agriculture, horticulture indus-.

  11. Recent advances within intensive Recirculated Aquaculture System cultivation of the calanoid copepod Acartia tonsa (Dana)

    DEFF Research Database (Denmark)

    Jepsen, Per Meyer; Højgaard, Jacob Kring; Drillet, Guillaume

    2014-01-01

    aquaculture species. Copepodites and nauplii are superior as live feed compared to rotifers and Artemia both in terms of nutritional value, behaviour and prey size. In 1980s the copepod Acartia tonsa (Dana) was isolated in the Danish strait of Øresund and has been studied and kept in cultures ever since...

  12. Urine culture

    Science.gov (United States)

    Culture and sensitivity - urine ... when urinating. You also may have a urine culture after you have been treated for an infection. ... when bacteria or yeast are found in the culture. This likely means that you have a urinary ...

  13. Safeguards Culture

    Energy Technology Data Exchange (ETDEWEB)

    Frazar, Sarah L.; Mladineo, Stephen V.

    2012-07-01

    The concepts of nuclear safety and security culture are well established; however, a common understanding of safeguards culture is not internationally recognized. Supported by the National Nuclear Security Administration, the authors prepared this report, an analysis of the concept of safeguards culture, and gauged its value to the safeguards community. The authors explored distinctions between safeguards culture, safeguards compliance, and safeguards performance, and evaluated synergies and differences between safeguards culture and safety/security culture. The report concludes with suggested next steps.

  14. Organizational Culture in Educational Institutions

    Science.gov (United States)

    Efeoglu, I. Efe; Ulum, Ömer Gökhan

    2017-01-01

    The concept of culture closely refers to a wide scope of effects on how individuals act in a group, an institution, or a public place. Chiefly, it covers a range of universal ideas, beliefs, values, behaviors, criterion, and measures which may be both explicit and implicit. The study on organizational culture has gained much attention among…

  15. Organizational Culture

    Directory of Open Access Journals (Sweden)

    Adrian HUDREA

    2006-02-01

    Full Text Available Cultural orientations of an organization can be its greatest strength, providing the basis for problem solving, cooperation, and communication. Culture, however, can also inhibit needed changes. Cultural changes typically happen slowly – but without cultural change, many other organizational changes are doomed to fail. The dominant culture of an organization is a major contributor to its success. But, of course, no organizational culture is purely one type or another. And the existence of secondary cultures can provide the basis for change. Therefore, organizations need to understand the cultural environments and values.

  16. Prototype recirculating aquaculture system design for juvenile red drum production as part of the Florida Fish and Wildlife Conservation commission’s Hatchery Network Initative

    Science.gov (United States)

    A prototype recirculating aquaculture system for the production of red drum (Sciaenops ocellatus) includes four 10-foot diameter by four foot height tanks for a tank volume of approximately 300 ft3 each (2200 gallons). Water flow for the system is provided for by a low head propeller pump which prov...

  17. Evaluating the chronic effects of nitrate on the health and performance of post-smolt Atlantic salmon Salmo salar in freshwater recirculation aquaculture systems

    Science.gov (United States)

    Commercial production of Atlantic salmon smolts, post-smolts, and market-size fish using land-based recirculation aquaculture systems (RAS) is expanding. RAS generally provide a nutrient-rich environment in which nitrate accumulates as an end-product of nitrification. An 8-month study was conducted ...

  18. Fillet quality and processing attributes of postsmolt Atlantic salmon, Salmo salar, fed a fishmeal-free diet and a fishmeal-based diet in recirculation aquaculture systems

    Science.gov (United States)

    Many studies have evaluated the adequacy of alternate ingredient diets for Atlantic salmon, Salmo salar, mainly with focus on fish performance and health; however, comprehensive analysis of fillet quality is lacking, particularly for salmon fed these diets in recirculation aquaculture systems (RAS)....

  19. The dinoflagellates Pfiesteria shumwayae and Luciella masanensis cause fish kills in recirculation fish farms in Denmark

    DEFF Research Database (Denmark)

    Moestrup, Øjvind; Hansen, Gert; Daugbjerg, Niels

    2014-01-01

    Fish kills in two geographically separate fish farms in northern Denmark in 2012, one using marine, the other brackish water 'Recirculation Aquaculture Systems' (RAS), were found to be caused by Pfiesteria shumwayae and Luciella masanensis, two species of dinoflagellates belonging to the family P...

  20. Stressing fish in Recirculating Aquaculture Systems (RAS): Does stress induced in one group of fish affect the feeding motivation of other fish sharing the same RAS?

    NARCIS (Netherlands)

    Martins, C.I.; Eding, E.H.; Verreth, J.A.J.

    2011-01-01

    As a consequence of water re-use and high stocking densities, Recirculating Aquaculture Systems (RAS) may lead to an accumulation of substances released by the fish into the water, e.g. cortisol and alarm pheromones. This study investigated the effect of stressing fish on the feeding motivation of