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1

Water quality trials in four recirculating aquacultural system configurations  

Microsoft Academic Search

Four circular, 2000-l, fiberglass tanks in four independent, indoor recirculating aquacultural systems were stocked with hybrid striped bass fingerlings (60-g average weight) at similar densities (320 fish\\/tank at the start of the study). The four systems represented four different recirculating system configurations as obtained by the combination of two types of biofilters (trickling and bead) and two types of solids

Sahdev Singh; James Ebeling; Fredrick Wheaton

1999-01-01

2

Control strategies for domestic hot water recirculation systems  

SciTech Connect

The purpose of a domestic hot water (DHW) recirculation system is to decrease the time spent waiting for the water to be delivered at acceptable temperatures when called for and also decrease the subsequent water consumption. The research detailed in this paper considered whether it is necessary to continuously run these recirculation pumps, as is general practice, or whether it is possible to reduce DHW system energy consumption by operating these pumps with some type of control strategy. Three different control strategies were evaluated by employing detailed monitoring. The different operating modes were: (1) base case (continuous operation), (2) shutdown during the overnight period, (3) shutdown during the peak morning and evening periods, and (4) cycling by a return line aquastat set at 110 F (61 C). In order to accomplish the research, six sites each had an aquastat installed onto the DHW return line and a programmable timeclock wired into the pump. The analysis identifies the relative energy use for each of the strategies during four round-robin rounds of two weeks each during the spring, summer, fall, and winter periods. When compared to the base case, (pump running 24 hours per day), Strategy B saves an average of 6%, Strategy C saves 6%, and Strategy D saves 11% of the DHW portion of a building's DHW energy requirements annually. This is significant in that for Strategy D, this translates into a savings of 4% of the building's total annual fuel bill. All of the control strategies evaluated were simple and employed low-cost devices (under $250 installed), which should help in achieving an extremely large implementation rate for the control strategy recommended. Tenant water quality survey questionnaires show that there was always an acceptable level of satisfaction, regardless of system control strategy.

Goldner, F.S.

1999-07-01

3

Exhaust gas recirculation system  

Microsoft Academic Search

In an exhaust gas recirculation system for internal combustion engines having a detachable gasket member between an exhaust gas recirculation valve and an exhaust pipe of the engine, the exhaust gas recirculation rate is controlled by a flow control orifice formed in the detachable gasket member. The recirculation valve can be applied to various types of engines requiring various recirculation

K. Numata; Y. Muramatu

1977-01-01

4

A Semiclosed Recirculating-Water System for High-Density Culture of Rainbow Trout  

Microsoft Academic Search

Water recirculating systems for fish culture are potentially desirable for conserving water and reducing heating requirements, maximizing production of fish under water and space limitations, minimizing effluent problems, and maintaining better control over environmental factors. A semiclosed recirculating-water system for intensive culture of rainbow trout Oncorhynchus mykiss is described. The system used self-cleaning, rectangular, cross-flow rearing tanks (water volume, 9

John M. Heinen; Joseph A. Hankins; Amy L. Weber; Barnaby J. Watten

1996-01-01

5

Halogen compatible treatment programs for open recirculating cooling water systems  

SciTech Connect

Stabilized phosphate cooling water programs have been exceptionally effective and well established in the marketplace for close to twenty years. Identification of this technology allowed chromate to be eliminated from open recirculating systems, providing less toxic operating conditions. However, very good control of stabilized phosphate applications is necessary in order to ensure chrome-like corrosion and deposit control performance. Difficulties with stabilized phosphate technology have occurred when it is used along with chlorine. Elevated chlorine dosages are sometimes necessary for microbial control. When this occurs, copper induced pitting becomes a concern as does the degradation of the cooling water program itself, i.e. phosphonate reversion. New programs have been identified which maintain their component integrity in the presence of chlorine. They offer improved deposit control performance under a variety of stressed cooling water conditions by using select polymer blends, as opposed to a single polymer. They also incorporate a new azole corrosion inhibition chemistry which minimizes copper-induced pitting associated with over-chlorination. Laboratory and field experience with this technology is discussed.

Kessler, S.M.; Given, K.M.

1999-07-01

6

Final cooling of coke oven gas using a closed-loop, recirculated wash-water system  

Microsoft Academic Search

Bethlehem Steel Corporation has developed a closed-loop, recirculated wash-water system for the final cooling of coke oven gas streams. The system employs physical separation of suspended solids from the cooling water, indirect cooling of the recirculating water, and injection of a small amount of a water-immiscible solvent to minimise the deposition of naphthalenic solids in the indirect heat exchanger. A

R. E. Watkins; K. R. Burcaw

1983-01-01

7

The chemistry of a new water-recirculation aquaculture system with emphasis on the influence of ozone on water quality.  

E-print Network

??Water quality changes that occur during establishment and maintenance of nitrification in two identical recirculating aquaculture systems containing rainbow trout are described. The time taken… (more)

Stobart, Michael David

1992-01-01

8

Exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system is disclosed which includes a control valve inserted in an exhaust gas recirculation passageway for controlling the flow rate of the exhaust gases to be recirculated, a constant pressure chamber defined in the recirculation passageway upstream of the control valve, and a modulator valve with a diaphragm chamber in communication with the constant pressure chamber

S. Nakamura; H. Nohira; H. Tokuda

1980-01-01

9

Exhaust gas recirculating system  

Microsoft Academic Search

An internal combustion engine equipped with an exhaust gas recirculating system is described. The exhaust gas recirculating system comprises an EGR valve normally closing an EGR duct to prevent recirculation and movable by a signal vacuum applied thereto to an open position and control means operable to provide a signal vacuum. The control means includes a vacuum line connecting a

Harada

1978-01-01

10

Final cooling of coke oven gas using a closed-loop, recirculated wash-water system  

SciTech Connect

Bethlehem Steel Corporation has developed a closed-loop, recirculated wash-water system for the final cooling of coke oven gas streams. The system employs physical separation of suspended solids from the cooling water, indirect cooling of the recirculating water, and injection of a small amount of a water-immiscible solvent to minimise the deposition of naphthalenic solids in the indirect heat exchanger. A process patent (US Patent 4.234.389) has been awarded to Bethlehem for the solvent-injection portion of the process. Based on the results of plant trials, the system has been proven to require less capital investment and to be more economical and more reliable to operate than the standard recirculated wash-oil systems. When compared with existing wash-water systems, the system has the advantage of eliminating the atmospheric discharges associated with open cooling towers.

Watkins, R.E.; Burcaw, K.R.

1983-01-01

11

Design and Evaluation of Recirculating Water Systems for Maintenance and Propagation of Freshwater Mussels  

Microsoft Academic Search

A complete system for culturing, rearing, and holding juvenile and adult freshwater mussels (Unionidae) was designed and evaluated for use at hatcheries and research facilities. The system includes air delivery, water conditioning and delivery, algal culturing and automated algal feed delivery, and air-driven water-recirculating units. These systems are appropriate for holding and conditioning adult mussels for spawning, as well as

William F. Henley; Lora L. Zimmerman; Richard J. Neves; Mark R. Kidd

2001-01-01

12

A design study on the optimal water refreshment rate in recirculating aquaculture systems  

Microsoft Academic Search

Refreshment (make-up) water is used in recirculating aquaculture systems (RAS) mainly to purge off-flavors, to add alkalinity and sometimes for temperature control. Alternatively, alkalinity may be added by means of a chemical base and heat may be supplied by a heating system. The objective of this study is to show how the optimal (minimizing cost) mix of the three controls:

Ido Seginer; Noam Mozes; Ori Lahav

2008-01-01

13

Exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system for use in an internal combustion engine includes an intake manifold having a riser portion serving as a heating source for an intake mixture charge, an exhaust gas recirculation passage running from an exhaust manifold to an intake system for introducing part of exhaust gases from the former to the latter, and a temperature-responsive valve

N. Kawai; H. Yamamoto

1980-01-01

14

Improving Heating System Operations Using Water Re-Circulation  

E-print Network

. The adjustment formulas of the relative flow rate and temperatures of supply and return water for both primary and secondary circuits of the system are deduced. The corresponding adjustment curves are plotted with calculating examples. Analysis of the curves...

Li, F.; Han, J.

2006-01-01

15

Exhaust gas recirculation system  

Microsoft Academic Search

An auxiliary flow control valve is disposed in an exhaust gas recirculation passageway at a location upstream of a main flow control valve controlling the flow rate of exhaust gases recirculated into an intake system. Two conduits communicating with an intake manifold communicate with a vacuum chamber of a servo motor controlling the main flow control valve. One of the

Y. Fujikawa; Y. Nakajima; Y. Hayashi; K. Sugihara; Y. Hase

1976-01-01

16

Exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system comprises a valve assembly for controlling the recirculation of exhaust gases in such a manner as to maintain a difference between a first and second pressure at a predetermined value. The first pressure is a pressure in a zone in an air induction passage between a throttle valve therein and a flow restrictor disposed therein

Aoyama

1980-01-01

17

Use of Hydroponics to Maintain Quality of Recirculated Water in a Fish Culture System  

Microsoft Academic Search

Fish production, biofiltration, and hydroponics were linked in a closed system of recirculating water. Fish tanks were stocked with channel catfish (Ictalurus punctatus) and the fish were fed daily. A revolving plate-type biofilter was used. Three field varieties of tomatoes (Lycopericon esculentum) were planted in outdoor hydroponic tanks. Three production units were operated during the 1976 growing season. All significant

William M. Lewis; John H. Yopp; Harold L. Schramm JR; Alan M. Brandenburg

1978-01-01

18

Flowing recirculated-water system for inducing laboratory spawning of sea lampreys  

USGS Publications Warehouse

We describe a water-recirculating system for inducing spawning of sea lampreys (Petromyzon marinus) held under laboratory conditions. Water temperature in the system was gradually increased to and maintained at 18 +/- 2 degrees C, the optimal temperature for spawning. About 10% freshwater was added daily to prevent buildup of waste products. Sea lampreys were provided substrate (approximately 3-6 cm in diameter) to build nests, and a water velocity of 0.2-0.3 m/s was maintained with an electric trolling motor. Sea lampreys held in this system exhibited characteristic spawning behavior. Prolarvae produced from artificial fertilization of gametes developed according to the standard timeline.

Fredricks, Kim T.; Seelye, James G.

1995-01-01

19

High-rate algal pond treatment for water reuse in an integrated marine fish recirculating system: effect on water quality and sea bass growth  

Microsoft Academic Search

A high-rate algae pond (HRAP) was tested as a second loop of water treatment in a recirculating fish rearing system to reduce water requirements and nutrient discharge levels. Three duplicated groups of sea bass (mean initial body weight 35±11 g) were reared under different system conditions (flow-through system, recirculating system and recirculating system with HRAP) for 1 year. Fish survival

Geneviève Deviller; Catherine Aliaume; Miguel Angel Franco Nava; Claude Casellas; Jean Paul Blancheton

2004-01-01

20

CORROSION OF COPPER IN OPEN RECIRCULATING WATER SYSTEMS  

Microsoft Academic Search

The cause of corrosion in condensers used in the Gaseous Diffusion ; Process has been investigated. The pitting of copper condenser tubes was caused ; by a combination of two independent conditions. The presence of copper oxide ; deposits on the tubes when purchased and their use with a cooling water ; containing ferrocyanide were the causes of the rapid

1959-01-01

21

Particle sieve analysis for determining solids removal efficiency of water treatment components in a recirculating aquaculture system  

Microsoft Academic Search

Recirculating aquaculture systems offer potential finfish production units for small-scale entities as well as large-scale operations. However, the water treatment components of such systems require efficient and proper operation to assure successful production. This study evaluated the solids removal ability of three water treatment components in a two-tank recirculating aquaculture system (28m3) utilized for the warmwater production of tilapia. The

Timothy J. Pfeiffer; Andrew Osborn; Megan Davis

2008-01-01

22

Exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine is disclosed in which an exhaust gas control valve and a pressure regulating valve is constructed as one body to facilitate the mounting of the system on the engine and to improve the response characteristic of the system. Also, the chamber of the pressure regulating valve opposite to the chamber

S. Hayashi; N. Shibata; Y. Takahara; S. Yamada

1981-01-01

23

Exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine. The internal combustion engine including at least one combustion chamber; an intake mechanism for delivering a combustible fluid mixture to the combustion chamber; an ignition system for igniting the combustible mixture; and an exhaust system for carrying exhaust fluid produced by the combustion of the combustible fluid mixture away from

Freesh

1982-01-01

24

Exhaust gas recirculating system  

Microsoft Academic Search

This patent describes an exhaust gas recirculating system for an internal combustion engine having an intake passage, a main throttle valve located in the intake passage, and an exhaust passage. The engine is installed in an automotive vehicle provided with a traction control system including means for sensing slippage of a drive wheel of the vehicle during acceleration, a second

H. Takahashi; T. Naganawa

1988-01-01

25

Exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system for cleaning exhaust gas from an internal combustion engine is provided in which a variable constriction is provided between an intake pipe and a pressure control valve in operative connection to a throttle valve in the carburetor and the pressure differential across said variable constriction is maintained constant to keep off any influence of the

M. Minoura; K. Yorioka

1980-01-01

26

Exhaust gas recirculation system  

Microsoft Academic Search

An engine exhaust gas recirculation (EGR) system is provided in which a sonic flow EGR valve is moved to open positions to establish a different constant rate of flow at each open position of the EGR valve in response to air pressure acting on a servo means secured to the valve, the air pressure force being controlled by changes in

Rachedi

1983-01-01

27

Exhaust gas recirculation system  

Microsoft Academic Search

The EGR control system comprises EGR control valve means including a first fluid chamber the vacuum in which increases and decreases in accordance with operating conditions of the engine whereby EGR control valve means control the recirculated amount of exhaust gases back to the engine and a second fluid chamber receiving therein a suction vacuum to thereby cause multiplication of

Aoyama

1979-01-01

28

Exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system is described for an engine having a throttle valve in an intake passage, comprising: the intake passage having an EGR port provided adjacent to the upstream side of the throttle valve at the closed position. A control port provides a position at downstream of the throttle valve at the closed position. A leak port provides

Sugiura

1987-01-01

29

Closed water recirculating system for fish rearing equipped with bioreactor capable of simultaneous nitrification and denitrification.  

PubMed

Five crucian carp, Carassius auratus langsdorfiicarps had been reared in a closed water recirculating system. The system was equipped with the compact bioreactor using the plate gels capable of both nitrification and denitrification in a single unit. Ammonia and nitrite concentrations in the rearing water had been maintained below 0.05 mg-N/L, and nitrate concentration also controlled between 2 and 8 mg-N/L with the bioreactor. As concerns nitrogen budget in the closed system, 95.0% of nitrogen income from feed was lost as nitrogen gas from the closed system. All fish was alive for 91 days without any unusual behavior. Thus, the bioreactor performed both nitrification and denitrification abilities enough to rear the five fish for 91 days. The bioreactor using the plate gels would be effective to simplify the closed system both physically and operationally, since it can remove the ammonia excreted from fish as nitrogen gas by a single step. PMID:11542800

Uemoto, H; Watanabe, A; Saitoh, S; Kondo, T; Matuki, Y; Masukawa, M; Matsumura, H; Koike, Y

1999-12-01

30

Nitrification in brackish water recirculating aquaculture system integrated with activated packed bed bioreactor.  

PubMed

Recirculation aquaculture systems (RAS) depend on nitrifying biofilters for the maintenance of water quality, increased biosecurity and environmental sustainability. To satisfy these requirements a packed bed bioreactor (PBBR) activated with indigenous nitrifying bacterial consortia has been developed and commercialized for operation under different salinities for instant nitrification in shrimp and prawn hatchery systems. In the present study the nitrification efficiency of the bioreactor was tested in a laboratory level recirculating aquaculture system for the rearing of Penaeus monodon for a period of two months under higher feeding rates and no water exchange. Rapid setting up of nitrification was observed during the operation, as the volumetric total ammonia nitrogen removal rates (VTR) increased with total ammonia nitrogen (TAN) production in the system. The average Volumetric TAN Removal Rates (VTR) at the feeding rate of 160 g/day from 54-60th days of culture was 0.1533+/-0.0045 kg TAN/m(3)/day. The regression between VTR and TAN explained 86% variability in VTR (P<0.001). The laboratory level RAS demonstrated here showed high performance both in terms of shrimp biomass yield and nitrification and environmental quality maintenance. Fluorescent in-situ Hybridization analysis of the reactor biofilm ensured the presence of autotrophic nitrifier groups such as Nitrosococcus mobilis lineage, Nitrobacter spp and phylum Nitrospira, the constituent members present in the original consortia used for activating the reactors. This showed the stability of the consortia on long term operation. PMID:20150717

Rejish Kumar, V J; Joseph, Valsamma; Philip, Rosamma; Bright Singh, I S

2010-01-01

31

Microparticles in recirculating aquaculture systems: particle size analysis of culture water from a commercial Atlantic salmon site  

Microsoft Academic Search

As part of a larger study of micro-particles in a recirculating, cold water aquaculture system for juvenile Atlantic salmon (Salmo salar), particle size analyses were carried out on the culture and makeup waters over several months followed by samples of feed stirred in water. The particle size distributions followed the power law described in [Aquacult. Eng. 19 (1999): 259] but

R. N. Patterson; K. C. Watts

2003-01-01

32

Exhaust gas recirculation system  

SciTech Connect

An exhaust gas recirculation system is described for an engine having a throttle valve in an intake passage, comprising: the intake passage having an EGR port provided adjacent to the upstream side of the throttle valve at the closed position. A control port provides a position at downstream of the throttle valve at the closed position. A leak port provides at upstream of the throttle valve; an EGR valve recirculates exhaust gases to the intake passage. The EGR valve has a diaphragm defining a first chamber applied with the pressure at the EGR port and a second chamber is applied with the pressure at the leak port. A valve body connects to the diaphragm for controlling the amount of recirculated gases; a control valve has a diaphragm defining a first control chamber and a second control chamber, and valve means on the diaphragm. The first control chamber is pressured at the EGR port. The second control chamber is applied with the pressure at the control port through a first conduit having an end port and with the pressure at the leak port through a second conduit. The valve means is arranged to open the end port of the first conduit when the difference between pressures in the first and second control chambers exceeds a predetermined value. Pressure regulating means renders the pressure in the second control chamber lower than the pressure in the second chamber of the EGR valve.

Sugiura, K.

1987-08-04

33

An integrated recirculating aquaculture system (RAS) for land-based fish farming: The effects on water quality and fish production  

Microsoft Academic Search

To mitigate the serious water pollution caused by the rapid expansion of the aquaculture industry in recent years, the development of improved aquaculture systems with more efficient water usage and less environmental impact has become essential. In this study, a land-based recirculating aquaculture system (RAS) was established that consisted of purification units (i.e., a primary biological pond, two parallel horizontal

Shi-Yang Zhang; Gu Li; Hui-Bi Wu; Xing-Guo Liu; Yan-Hong Yao; Ling Tao; Huang Liu

34

Exhaust gas recirculation system  

Microsoft Academic Search

In response to the operation of an internal combustion engine, an input signal pressure is developed which differs from the atmospheric pressure by more than a first predetermined amount when exhaust gas recirculation is desirable. A recirculation valve then opens to permit the recirculation of exhaust gases from the exhaust passage to the intake passage of the engine. In response

1975-01-01

35

Exhaust gas recirculation system  

SciTech Connect

An engine exhaust gas recirculation (EGR) system is provided in which a sonic flow EGR valve is moved to open positions to establish a different constant rate of flow at each open position of the EGR valve in response to air pressure acting on a servo means secured to the valve, the air pressure force being controlled by changes in a control vacuum opposing the air pressure force and modified by an air bleed device as a function of changes in engine exhaust gas backpressure levels, to provide an EGR valve movement that varies essentially in proportion to changes in engine air flow.

Rachedi, S.H.

1983-08-30

36

Combustion-gas recirculation system  

Microsoft Academic Search

A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end

Darryl Dean

2007-01-01

37

Enrichment of inorganic trace pollutants in re-circulated water streams from a wet limestone flue gas desulphurisation system in two coal power plants  

Microsoft Academic Search

The enrichment of inorganic trace pollutants in re-circulated water streams was studied at two power plants equipped with wet limestone Flue Gas Desulphurisation (FGD) system from the first re-circulation cycle of water up to the start of sampling campaigns. To elucidate the enrichment of inorganic trace pollutants as result of water re-circulation, a partial and total mass balances were undertaken.

Patricia Córdoba; María Izquierdo; Xavier Querol; Aurelio Tobías; María Antonia López-Antón; Raquel Ochoa-Gonzalez; Mercedes Díaz-Somoano; M. Rosa Martínez-Tarazona; Carlos Ayora; Carlos Leiva; Constantino Fernández; Antonio Giménez

2011-01-01

38

Principles of Water Recirculation and Filtration in Aquaculture 1  

E-print Network

FA12 Principles of Water Recirculation and Filtration in Aquaculture 1 Michael McGee and Charles water systems are designed to minimize or reduce dependence on water exchange and flushing in fish tanks, and aquaria systems, as well as small scale aquaculture projects. Water is typically recirculated

Watson, Craig A.

39

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

Microsoft Academic Search

Two studies were conducted to evaluate rainbow trout Oncorhynchus mykiss health and welfare within replicated water recirculating aquaculture systems (WRAS) that were operated at low and near-zero water exchange, with and without ozonation, and with relatively high feed loading rates. During the first study, rainbow trout cultured within WRAS operated with low water exchange (system hydraulic retention time (HRT)=6.7 days;

John Davidson; Christopher Good; Carla Welsh; Steven T. Summerfelt

40

Exhaust gas recirculation system  

Microsoft Academic Search

Apparatus for controlling exhaust gas recirculation in an internal combustion engine employs a first control valve in an exhaust gas recirculation passageway, a second control valve in an air conduit connecting the intake passage to atmosphere through selective restriction means, and a regulating valve responsive to differential vacuum intensities for actuating the control valves. The restriction means comprise a plurality

Y. Itoh; A. Totsune; H. Yamabe

1982-01-01

41

Exhaust gas recirculation system  

Microsoft Academic Search

In a diesel engine having a turbocharger for feeding supercharged air to the engine, an exhaust gas recirculation passage communicates between the exhaust passage from the engine and the intake passage to a compressor of the turbocharger. A first control valve closes the exhaust gas recirculation passage when the output pressure of the air leading from the compressor is lower

Yoshiba

1982-01-01

42

The effects of carbon dioxide on performance and histopathology of rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems  

Microsoft Academic Search

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 aquaculture systems (WRAS), pumping can be a significant cost for operators. A 6-month trial was conducted to compare the

Christopher Good; John Davidson; Carla Welsh; Kevin Snekvik; Steven Summerfelt

2010-01-01

43

Impact of water quality on the bacterial populations and off-flavours in recirculating aquaculture systems.  

PubMed

A variety of factors affecting water quality in recirculating aquaculture systems (RAS) are associated with the occurrence of off-flavours. In this study, we report the impact of water quality on the bacterial diversity and the occurrence of the geosmin-synthesis gene (geoA) in two RAS units operated for 252 days. Unit 2 displayed a higher level of turbidity and phosphate, which affected the fresh water quality compared with unit 1. In the biofilter, nitrification is one of the major processes by which high water quality is maintained. The bacterial population observed in the unit 1 biofilter was more stable throughout the experiment, with a higher level of nitrifying bacteria compared with the unit 2 biofilter. Geosmin appeared in fish flesh after 84 days in unit 2, whereas it appeared in unit 1 after 168 days, but at a much lower level. The geoA gene was detected in both units, 28 days prior to the detection of geosmin in fish flesh. In addition, we detected sequences associated with Sorangium and Nannocystis (Myxococcales): members of these genera are known to produce geosmin. These sequences were observed at an earlier time in unit 2 and at a higher level than in unit 1. This study confirms the advantages of new molecular methods to understand the occurrence of geosmin production in RAS. PMID:23228051

Auffret, Marc; Yergeau, Étienne; Pilote, Alexandre; Proulx, Émilie; Proulx, Daniel; Greer, Charles W; Vandenberg, Grant; Villemur, Richard

2013-05-01

44

Hexachlorobenzene uptake by fathead minnows and macroinvertebrates in recirculating sediment/water systems.  

PubMed

Fathead minnows (Pimephales promelas), the worm, Lumbriculus variegatus, and the amphipods Hyalella azteca and Gammarus lacustris were exposed to hexachlorobenzene (HCB) in water with and without a bed of HCB-spiked sediment. Water HCB concentrations were maintained by recirculation through HCB-packed columns. Recirculating HCB-bound particulates and possibly eroded HCB particulates were an added source of HCB in addition to the sediment bed. Significant bioaccumulation of HCB in animal tissues was observed in water-only and water-sediment exposures. The presence of the HCB-spiked sediment did not result in a significant increase in the uptake of HCB by the organisms, but there was a substantial increase in sediment HCB levels over time. Higher tissue HCB levels in aquaria without sediment suggest that the sediment was a more efficient sink for HCB than the organisms. PMID:2331142

Schuytema, G S; Krawczyk, D F; Griffis, W L; Nebeker, A V; Robideaux, M L

1990-01-01

45

Hexachlorobenzene uptake by fathead minnows and macroinvertebrates in recirculating sediment/water systems  

SciTech Connect

Fathead minnow (Pimephales promelas), the worm, Lumbriculus variegatus, and the amphipods Hyalella azteca and Gammarus lacustris were exposed to hexachlorobenzene (HCB) in water with and without a bed of HCB-spiked sediment. Water HCB concentrations were maintained by recirculation through HCB-packed columns. Recirculating HCB-bound particulates and possibly eroded HCB particulates were an added source of HCB in addition to the sediment bed. Significant bioaccumulation of HCB in animal tissues was observed in water-only and water-sediment exposures. The presence of the HCB-spiked sediment did not result in a significant increase in the uptake of HCB by the organisms, but there was a substantial increase in sediment HCB levels over time. Higher tissue HCB levels in aquaria without sediment suggest that the sediment was a more efficient sink for HCB than the organisms.

Schuytema, G.S.; Krawczyk, D.F.; Griffis, W.L.; Nebeker, A.V.; Robideaux, M.L.

1990-01-01

46

Engine exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine employs a recirculation control valve in a passageway connecting the engine exhaust passage to the engine intake passage downstream from the throttle valve. An air conduit having an air control valve therein furnishes atmospheric air to the intake passage downstream from the throttle valve. Vacuum responsive actuators are provided for

H. Nishimura; T. Shioya; T. Umemoto

1981-01-01

47

Engine exhaust gas recirculation system  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine employs a recirculation control valve in a passageway connecting the engine exhaust passage to the engine intake passage downstream from the throttle valve. An air conduit having an air control valve therein draws atmospheric air into the intake passage downstream from the throttle valve. Vacuum responsive actuators are provided for

K. Ishii; H. Nishimura; K. Osawa

1981-01-01

48

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

Microsoft Academic Search

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

Hans C. K Madsen; Kurt Buchmann; Stig Mellergaard

2000-01-01

49

The use of an open channel, low pressure UV reactor for water treatment in low head recirculating aquaculture systems (LH-RAS)  

Microsoft Academic Search

This study examined the effectiveness of an open channel, low pressure (LP), ultraviolet (UV) reactor for water treatment in a low head (LH) recirculating aquaculture system (RAS). Currently available UV reactors use high pressure pumps and submerged bulbs. The reactor in this study makes use of the head gained by the water recirculation of the LH-RAS without the need for

Hadas Mamane; Angelo Colorni; Ido Bar; Ido Ori; Noam Mozes

2010-01-01

50

Reduction in the make-up water in semi-closed recirculating aquaculture systems  

Microsoft Academic Search

Three feeding trials with rainbow trout (Oncorhynchus mykiss) were run in a closed recirculating aquaculture system with a nitrification unit and a sedimentation tank. The used trout feed had first a protein content of 47.9% (no. 1) and afterwards a protein content of 38.5% (no. 2). The effects of different protein contents of the feeds (trial I and II) and

C Schuster; H Stelz

1998-01-01

51

Fish Health Management Considerations in Recirculating Aquaculture Systems -Part 1  

E-print Network

Cir 120 Fish Health Management Considerations in Recirculating Aquaculture Systems - Part 1 Cooperating. Nick T. Place , Dean Introduction Recirculating aquaculture systems, also known as water reuse in Recirculating Aquaculture Systems: Parts 1, 2 and 3 ­ provides basic information that should assist

Watson, Craig A.

52

Combustion-gas recirculation system  

DOEpatents

A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end of the open inlet channel is disposed between the mixing-chamber inlet and the mixing-chamber outlet. Furthermore, air within the open inlet channel may be at a pressure near or below atmospheric pressure.

Baldwin, Darryl Dean (Lacon, IL)

2007-10-09

53

Is growth retardation present in Nile tilapia Oreochromis niloticus cultured in low water exchange recirculating aquaculture systems?  

Microsoft Academic Search

It has been suggested that fish cultured in recirculating aquaculture systems (RAS) grow less as compared with fish cultured in flow-through systems due to the accumulation of substances. In the Netherlands, the commercial culture of Nile tilapia Oreochromis niloticus in 300 and 600MT's systems is done exclusively in RAS operated at water exchange rates as low as 30L\\/kg feed\\/day due

Catarina I. M. Martins; Daniel Ochola; Stephan S. W. Ende; Ep H. Eding; Johan A. J. Verreth

2009-01-01

54

Water Treatment and Performance Characteristics Evaluation of a Pilot-Scale Recirculating Aquaculture System  

Microsoft Academic Search

To minimize the impact on the environment and land requirements, a pilot-scale recirculating aquaculture system was engineered and investigated in a greenhouse. The system included a three-step particulates separation device, fluidized bed reactors (FBR), UV treatment and cooling. Japanese flounder (Paralichthys olivaceus) were raised from initial mean weight 4.9 plusmn 0.6g to final mean weight 35.8 plusmn 14.6g after 140

Yan Zaisheng; Liu Changfa; Wang Shihe; He Jie; Liu Yuan; Zhang Liyong; Zhang Junxin

2008-01-01

55

Effect of flow rate on water quality parameters and plant growth of water spinach (Ipomoea aquatica) in an aquaponic recirculating system  

Microsoft Academic Search

Recirculating aquaculture–hydroponic systems were designed to provide an artificial, controlled environment that optimizes the growth of fish (or other aquatic species) and soil-less plants, complete control of water quality, the production schedule and the fish product, while conserving water resources. Nutrients removal such as inorganic nitrogen and phosphate is essential for aquaculture wastewater treatment to protect receiving waters from eutrophication

Azizah Endut; Ahmad Jusoh; Nora’aini Ali; W. N. S. Wan Nik; Anuar Hassan

2009-01-01

56

Exhaust-gas recirculation system  

Microsoft Academic Search

An exhaust-gas recirculation (EGR) system for an internal-combustion engine comprises an EGR valve for controlling the amount of exhaust-gas recirculation installed midway in an EGR passage that establishes communication between the intake and exhaust pipes of the engine, and an exhaust-gas transducer valve for opening and closing by the exhaust pressure of the exhaust gas an atmospheric-releasing orifice formed midway

K. Yamada; C. Niida; T. Takayama

1979-01-01

57

Evaluation of air-lift pump capabilities for water delivery, aeration, and degasification for application to recirculating aquaculture systems  

Microsoft Academic Search

A methodology is demonstrated for evaluating the feasibility of using air-lift pumps for water movement, aeration, and degasification in a recirculating aquaculture system. A set of empirical equations are presented modeling the performance of a 5.08-cm (2?) diameter air-lift submerged 91.44 cm (36?) with a 15.24-cm (6?) lift operated at 28–142 l min?1 (1–5 scfm) of air injection. A steady

J. Clay Loyless; Ronald F Malone

1998-01-01

58

A practical application for the chemical treatment of Southern California`s reclaimed, Title 22 water for use as makeup water for recirculating cooling water systems  

SciTech Connect

Pilot cooling water studies conducted at a Southern California landfill/cogeneration station demonstrated a successful chemical treatment program for recirculating cooling water that used unnitrified, reclaimed, Title 22 water as the primary makeup water source. The constituents in the reclaimed water are supplied by variety of residential and waste water sources resulting in a water quality that may vary to a greater degree than domestic water supplies. This water contains high concentrations of orthophosphate, ammonia, chlorides and suspended solids. The impact of which, under cycled conditions is calcium orthophosphate scaling, high corrosion of yellow metal and mild steel, stress cracking of copper alloys and stainless steel and rapidly growing biological activity. A mobile cooling water testing laboratory with two pilot recirculating water systems modeled the cogeneration station`s cooling tower operating conditions and parameters. The tube and shell, tube side cooling heat exchangers were fitted with 443 admiralty, 90/10 copper nickel, 316 stainless steel and 1202 mild steel heat exchanger tubes. Coupons and Corrater electrodes were also installed. A chemical treatment program consisting of 60/40 AA/AMPS copolymer for scale, deposits and dispersion, sodium tolyltriazole for yellow metal corrosion, and a bromination program to control the biological activity was utilized in the pilot systems. Recirculating water orthophosphate concentrations reached levels of 70 mg/L as PO, and ammonia concentrations reached levels of 35 mg/L, as total NH3. The study successfully demonstrated a chemical treatment program to control scale and deposition, minimize admiralty, 90/10 copper nickel and carbon steel corrosion rates, prevent non-heat transfer yellow metal and stainless steel stress cracking, and control the biological activity in this high nutrient water.

Zakrzewski, J. [Calgon Corp., Pittsburgh, PA (United States); Cosulich, J.; Bartling, E. [County Sanitation Districts of Los Angeles County, Whittier, CA (United States)

1998-12-31

59

Exhaust gas recirculation (EGR) system  

Microsoft Academic Search

This invention relates to electronically controlled exhaust gas recirculation valves and more particularly to systems incorporating an electrical vacuum regulator. It is therefore an object of the present invention to provide an EGR system that is less susceptible to output flow changes caused by carbon build up. A further object of the invention is to provide a vacuum regulator that

Cook

1984-01-01

60

Multistage exhaust gas recirculation system  

Microsoft Academic Search

An automotive type exhaust gas recirculation (EGR) system has two modes of operation, a first one that regulates EGR flow at a constant percentage rate as a function of throttle valve position independently of exhaust gas backpressure changes, and a second one that provides a variable percentage rate of flow of EGR gases in response to changes in exhaust gas

D. C. Ahrns; S. H. Rachedi

1983-01-01

61

Populations of heterotrophic bacteria in an experimental recirculating aquaculture system  

Microsoft Academic Search

The aim of this work was to identify the main viable heterotrophic bacteria in a marine fish farm with a recirculating water system and to study their growth dynamics. The experiments were performed with sea bass (Dicentrarchus labrax) in an experimental recirculating water system. The bacteria identified were typical of the marine environment: Pseudomonas, Oceanospirillum, Marinobacter, Paracoccus and Erythrobacter genus

N Leonard; J. P Blancheton; J. P Guiraud

2000-01-01

62

Exhaust gas recirculation flow control system  

Microsoft Academic Search

A closed-loop exhaust gas recirculation flow control system for minimizing nitrogen oxide emissions from internal combustion engines is described that, unlike prior-art devices, compensates for changes in sensed engine variables by incorporating feedback from the exhaust gas recirculation system. A valve that is responsive to engine air flow and to recirculated exhaust gas flow provides a scheduled flow control signal

Wertheimer

1974-01-01

63

Frequency of Aeromonas spp. detection in rainbow trout and recirculation aquaculture systems and the storage stability of fillets.  

E-print Network

??Recirculating aquaculture systems enable increased fish production per unit volume of water. Unfortunately, recirculation systems also provide conditions for bacterial growth. Aeromonas, a genus of… (more)

Littler, Tabetha Marie.

2007-01-01

64

The impact of water exchange rate on the health and performance of rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems  

Microsoft Academic Search

A controlled six-month study was conducted in six replicated water recirculation aquaculture systems (WRAS) to assess fish health indicators in relation to high feeding\\/low flushing conditions. Juvenile rainbow trout (Oncorhynchus mykiss) were stocked in six identical WRAS (1000 fish per system), and were maintained over the study period between 25 kg\\/m3 (minimum) and 80 kg\\/m3 (maximum) densities. Three WRAS received a relatively

Christopher Good; John Davidson; Carla Welsh; Brian Brazil; Kevin Snekvik; Steven Summerfelt

2009-01-01

65

Exhaust gas recirculation system  

Microsoft Academic Search

An EGR system is described in which the vacuum control valve is improved to comprise: a first diaphragm; a second diaphragm; a first chamber which is formed outside said first diaphragm and communicating with the atmosphere; a second chamber which is formed between said first and second diaphragm and communicating with the pressure control chamber of the EGR valve, and;

Suzuki

1977-01-01

66

Identification of Bacterial Pathogens in Biofilms of Recirculating Aquaculture Systems  

Microsoft Academic Search

Biofilms are capable of forming on all aquaculture system components, incorporating the various microflora present in the water. Pathogenic bacteria released from the biofilms are potentially capable of causing recurring diseases. Seven recirculating freshwater and two recirculating saltwater facilities were sampled, with eight different types of materials tested. Pathogenic bacteria were identified using standard bacteriological methods and commercial kits. The

Robin K. King; George J. Flick Jr; D. Pierson; Stephen A. Smith; Gregory D. Boardman; Charles W. Coale Jr

2004-01-01

67

Effects of elevated atmospheric carbon dioxide concentrations on water and acid requirements of soybeans grown in a recirculating hydroponic system  

NASA Technical Reports Server (NTRS)

Establishing mass budgets of various crop needs, i.e. water and nutrients, in different environments is essential for the Controlled Ecological Life Support System (CELSS). The effects of CO2 (500 and 1000 umol mol (exp -1)) on water and acid use (for pH control) by soybeans in a recirculating hydroponic system were examined. Plants of cvs. McCall and Pixie were grown for 90 days using the nutrient film technique (NFT) and a nitrate based nutrient solution. System acid use for both CO2 levels peaked near 4 weeks during a phase of rapid vegetative growth, but acid use decreased more rapidly under 500 compared to 1000 umol mol (exp GR) CO2. Total system water use by 500 and 1000 umol mol (exp -1) plants was similar, leaving off at 5 weeks and declining as plants senesced (ca. 9 weeks). However, single leaf transpiration rates were consistently lower at 1000 umol mol (exp -1). The data suggest that high CO2 concentrations increase system acid (and nutrient) use because of increased vegetative growth, which in turn negates the benefit of reduced water use (lower transpiration rates) per unit leaf area.

Mackowiak, C. L.; Wheeler, R. M.; Lowery, W.; Sager, J. C.

1990-01-01

68

In-tank recirculating arsenic treatment system  

DOEpatents

A low-cost, water treatment system and method for reducing arsenic contamination in small community water storage tanks. Arsenic is removed by using a submersible pump, sitting at the bottom of the tank, which continuously recirculates (at a low flow rate) arsenic-contaminated water through an attached and enclosed filter bed containing arsenic-sorbing media. The pump and treatment column can be either placed inside the tank (In-Tank) by manually-lowering through an access hole, or attached to the outside of the tank (Out-of-Tank), for easy replacement of the sorption media.

Brady, Patrick V. (Albuquerque, NM); Dwyer, Brian P. (Albuquerque, NM); Krumhansl, James L. (Albuquerque, NM); Chwirka, Joseph D. (Tijeras, NM)

2009-04-07

69

Exhaust gas recirculation system with engine load dependent performance  

Microsoft Academic Search

An exhaust gas recirculation system is disclosed, which is of the well-known type wherein an exhaust gas recirculation control valve in the exhaust gas recirculation passage controls the amount of exhaust gas recirculation. An orifice element, upstream of the exhaust gas recirculation valve in the passage, defines a pressure chamber between itself and the exhaust gas recirculation control valve. The

Onaka

1981-01-01

70

Use of Produced Water in Recirculated Cooling Systems at Power Generating Facilities  

SciTech Connect

Tree ring studies indicate that, for the greater part of the last three decades, New Mexico has been relatively 'wet' compared to the long-term historical norm. However, during the last several years, New Mexico has experienced a severe drought. Some researchers are predicting a return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters to supplement current fresh water supplies for power plant operation and cooling and other uses. The U.S. Department of Energy's National Energy Technology Laboratory sponsored three related assessments of water supplies in the San Juan Basin area of the four-corner intersection of Utah, Colorado, Arizona, and New Mexico. These were (1) an assessment of using water produced with oil and gas as a supplemental supply for the San Juan Generating Station (SJGS); (2) a field evaluation of the wet-surface air cooling (WSAC) system at SJGS; and (3) the development of a ZeroNet systems analysis module and an application of the Watershed Risk Management Framework (WARMF) to evaluate a range of water shortage management plans. The study of the possible use of produced water at SJGS showed that produce water must be treated to justify its use in any reasonable quantity at SJGS. The study identified produced water volume and quality, the infrastructure needed to deliver it to SJGS, treatment requirements, and delivery and treatment economics. A number of produced water treatment alternatives that use off-the-shelf technology were evaluated along with the equipment needed for water treatment at SJGS. Wet surface air-cooling (WSAC) technology was tested at the San Juan Generating Station (SJGS) to determine its capacity to cool power plant circulating water using degraded water. WSAC is a commercial cooling technology and has been used for many years to cool and/or condense process fluids. The purpose of the pilot test was to determine if WSAC technology could cool process water at cycles of concentration considered highly scale forming for mechanical draft cooling towers. At the completion of testing, there was no visible scale on the heat transfer surfaces and cooling was sustained throughout the test period. The application of the WARMF decision framework to the San Juan Basis showed that drought and increased temperature impact water availability for all sectors (agriculture, energy, municipal, industry) and lead to critical shortages. WARMF-ZeroNet, as part of the integrated ZeroNet decision support system, offers stakeholders an integrated approach to long-term water management that balances competing needs of existing water users and economic growth under the constraints of limited supply and potential climate change.

C. McGowin; M. DiFilippo; L. Weintraub

2006-06-30

71

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

72

Use of Produced Water in Recirculating Cooling Systems at Power Generating Facilities  

SciTech Connect

The purpose of this study is to evaluate produced water as a supplemental source of water for the San Juan Generating Station (SJGS). This study incorporates elements that identify produced water volume and quality, infrastructure to deliver it to SJGS, treatment requirements to use it at the plant, delivery and treatment economics, etc. SJGS, which is operated by Public Service of New Mexico (PNM) is located about 15 miles northwest of Farmington, New Mexico. It has four units with a total generating capacity of about 1,800 MW. The plant uses 22,400 acre-feet of water per year from the San Juan River with most of its demand resulting from cooling tower make-up. The plant is a zero liquid discharge facility and, as such, is well practiced in efficient water use and reuse. For the past few years, New Mexico has been suffering from a severe drought. Climate researchers are predicting the return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters. This deliverable describes possible test configurations for produced water demonstration projects at SJGS. The ability to host demonstration projects would enable the testing and advancement of promising produced water treatment technologies. Testing is described for two scenarios: Scenario 1--PNM builds a produced water treatment system at SJGS and incorporates planned and future demonstration projects into the design of the system. Scenario 2--PNM forestalls or decides not to install a produced water treatment system and would either conduct limited testing at SJGS (produced water would have to be delivered by tanker trucked) or at a salt water disposal facility (SWD). Each scenario would accommodate demonstration projects differently and these differences are discussed in this deliverable. PNM will host a demonstration test of water-conserving cooling technology--Wet Surface Air Cooling (WSAC) using cooling tower blowdown from the existing SJGS Unit 3 tower--during the summer months of 2005. If successful, there may be follow-on testing using produced water. WSAC is discussed in this deliverable. Recall that Deliverable 4, Emerging Technology Testing, describes the pilot testing conducted at a salt water disposal facility (SWD) by the CeraMem Corporation. This filtration technology could be a candidate for future demonstration testing and is also discussed in this deliverable.

Kent Zammit; Michael N. DiFilippo

2005-07-01

73

Exhaust gas recirculation (EGR) system  

SciTech Connect

This invention relates to electronically controlled exhaust gas recirculation valves and more particularly to systems incorporating an electrical vacuum regulator. It is therefore an object of the present invention to provide an EGR system that is less susceptible to output flow changes caused by carbon build up. A further object of the invention is to provide a vacuum regulator that can be used with simple, low cost EGR valves. Simple valves can be used by virtue of the closed loop vacuum regulation feature of the present invention since the flow rate/vacuum signal relationship is not important. A further object of the present invention is to provide an EGR flow regulation system which automatically compensates for pressure variations which result in changes in the pressure differential across the EGR valve due to changes in exhaust system pressure and intake manifold pressure. Many other objects and purposes of the invention will be clear from the following detailed description of the drawing.

Cook, J.E.

1984-09-04

74

Denitrification in recirculating systems: Theory and applications  

Microsoft Academic Search

Profitability of recirculating systems depends in part on the ability to manage nutrient wastes. Nitrogenous wastes in these systems can be eliminated through nitrifying and denitrifying biofilters. While nitrifying filters are incorporated in most recirculating systems according to well-established protocols, denitrifying filters are still under development. By means of denitrification, oxidized inorganic nitrogen compounds, such as nitrite and nitrate are

Jaap van Rijn; Yossi Tal; Harold J. Schreier

2006-01-01

75

Turbocharged engine exhaust gas recirculation system  

Microsoft Academic Search

Improved exhaust gas recirculation systems for turbocharged gas engines that include an exhaust pipe, a turbocharger connected thereto, and a carburetor connected with a source of gas for the engine. The recirculation system includes an air conduit extending from the turbocharger compressor discharge to a venturi, an exhaust gas conduit that extends from a connection with the exhaust pipe between

Stachowicz

1984-01-01

76

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

Microsoft Academic Search

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 the water and fish. Inductively-coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectroscope (ICP-MS) were used

Catarina I. M. Martins; Ep H. Eding; Johan A. J. Verreth

2011-01-01

77

Water and Energy Savings using Demand Hot Water Recirculating Systems in Residential Homes: A Case Study of Five Homes in Palo Alto, California  

SciTech Connect

This report summarizes a preliminary study aimed at estimating the potential of saving potable water, (and the electrical energy used to heat it), that is presently lost directly to the drain while occupants wait for hot water to arrive at the faucet (point of use). Data were collected from five single-family homes in Palo Alto, California. Despite the small sample size in this study, the results make a compelling case for retrofitting homes with hot water recirculation systems to eliminate unnecessary wastage of water at the point of use. Technical as well as behavioral and attitudinal changes towards water conservation are necessary for a fulfilling and successful conservation effort. This report focuses on the technical issues, but behavioral issues are also noted, which may be factored into future studies involving local and state governments and utility companies.

Ally, M.R.

2002-11-14

78

Orifice of exhaust gas recirculation system  

Microsoft Academic Search

In an exhaust gas recirculation system for an internal combustion engine, orifices disposed in a passage for recirculating the exhaust gas is made of a sheet of a bimetal or other material capable of changing from a normal shape to a deformed shape when the heat of the exhaust gas is applied, in order to prevent carbon contained in the

Fukae

1984-01-01

79

Control system for exhaust gas recirculating valve  

Microsoft Academic Search

An exhaust gas recirculation control system for an internal combustion engine is disclosed in which a pressure operated exhaust gas recirculation (EGR) valve governs the flow of engine exhaust gas into the engine intake. The EGR valve is supplied with operating pressure from the engine intake manifold via a pressure amplifier. The amplifier has a pressure input which tends to

Caldwell

1976-01-01

80

Self-calibrating exhaust gas recirculation system  

Microsoft Academic Search

A motor vehicle combustion engine has an exhaust gas recirculation system in which the flow of recirculated exhaust gas is controlled through an orifice having exhaust back pressure on one side and a control pressure on the other as determined by an EGR valve. A pressure transducer compares the control pressure with a reference pressure provided in part by an

R. J. Haka; D. D. Stoltman

1983-01-01

81

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine includes an exhaust gas recirculation passage for communicating an exhaust port with an intake passage through a recirculation flow control valve. The recirculation system according to the invention comprises a timing valve in the recirculation passage adapted to open at specified moments for extracting exhaust gases containing highly concentrated hydrocarbons.

H. Aihara; Y. Matsumoto; Y. Nakagawa; S. Suzuki

1981-01-01

82

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine is comprised of an exhaust gas recirculation passage for recirculating exhaust gases from an exhaust pipe into an intake pipe downstream of a throttle valve, a control valve responsive to a pressure signal for opening or closing said recirculation passage, a pressure chamber defined within the recirculation passage, a negative

T. Kohama; H. Obayashi; T. Ozaki; H. Nohira

1980-01-01

83

Exhaust gas recirculation control system  

SciTech Connect

A system is described for controlling exhaust gas recirculation (EGR) in an internal combustion engine: (a) base means defining an exhaust gas inlet port, an exhaust gas outlet port and an EGR passage communicating the inlet port with the outlet port, the base means adapted for attachment to an exhaust passage and a combustion chamber inlet passage of an engine; (b) flow valve means disposed in the passage and including a valve seat and poppet member operable upon movement with respect to the seat for controlling EGR flow between the inlet and the outlet; (c) actuator means operable upon receipt of an electrical control signal to move the poppet, the actuator means including: (i) a stepper motor, (ii) an axial lead means operatively rotated by the stepper motor, (iii) follower means guided for axial movement, and operably connected to move the poppet in response to rotation of the lead means; (d) plate means disposed in the EGR passage between the seat and the outlet port and defining a flow measuring orifice; (e) pressure tap means operative to sense the pressure in the passage on the upstream and downstream sides of the orifice; (f) transducer means operative in response to the pressure in the pressure tap means to provide the electrical control signal for the stepper motor.

Egle, L.E.

1987-09-01

84

USE OF PRODUCED WATER IN RECIRCULATING COOLING SYSTEMS AT POWER GENERATING FACILITIES  

SciTech Connect

The purpose of this study is to evaluate produced water as a supplemental source of water for the San Juan Generating Station (SJGS). This study incorporates elements that identify produced water volume and quality, infrastructure to deliver it to SJGS, treatment requirements to use it at the plant, delivery and treatment economics, etc. SJGS, which is operated by Public Service of New Mexico (PNM) is located about 15 miles northwest of Farmington, New Mexico. It has four units with a total generating capacity of about 1,800 MW. The plant uses 22,400 acre-feet of water per year from the San Juan River with most of its demand resulting from cooling tower make-up. The plant is a zero liquid discharge facility and, as such, is well practiced in efficient water use and reuse. For the past few years, New Mexico has been suffering from a severe drought. Climate researchers are predicting the return of very dry weather over the next 30 to 40 years. Concern over the drought has spurred interest in evaluating the use of otherwise unusable saline waters. Produced water is generated nationally as a byproduct of oil and gas production. Seven states generate 90 percent of the produced water in the continental US. About 37 percent of the sources documented in the US Geological Survey's (USGS) Produced Waters Database have a TDS of less than 30,000 mg/l. This is significant because produced water treatment for reuse in power plants was found to be very costly above 30,000 mg/l TDS. For the purposes of this report, produced water treatment was assessed using the technologies evaluated for the San Juan Generating Station (SJGS) in Deliverable 3, Treatment and Disposal Analysis. Also, a methodology was developed to readily estimate capital and operating costs for produced water treatment. Two examples are presented to show how the cost estimating methodology can be used to evaluate the cost of treatment of produced water at power plants close to oil and gas production.

Kent Zammit; Michael N. DiFilippo

2005-01-01

85

Exhaust gas recirculation control system  

Microsoft Academic Search

An EGR control valve is closably disposed in an EGR passageway connecting an intake passageway and an exhaust gas passageway which leads to an internal combustion engine. The EGR control valve is operated to control recirculated exhaust gas flow by varying the exhaust gas pressure in a chamber between a restriction disposed in the EGR passageway and the EGR valve,

Aoyama

1979-01-01

86

Exhaust gas recirculation control system  

Microsoft Academic Search

An exhaust gas recirculation (EGR) control valve is described. The valve is provided with an extension which is inserted into a restriction, formed in the EGR passageway upstream of the EGR control valve, to reduce the effective cross sectional area of the restriction and therefore the EGR ratio when the pressure in the EGR passageway between the restriction and the

Aoyama

1978-01-01

87

Exhaust gas recirculation control system  

Microsoft Academic Search

An EGR control valve is closely disposed in an EGR passageway connecting an intake passageway and an exhaust gas passageway which leads to an internal combustion engine. The EGR control valve is operated to control recirculated exhaust gas flow by varying the exhaust gas pressure in a chamber between a restriction disposed in the EGR passageway and the EGR valve,

Aoyama

1978-01-01

88

Numerical Analysis of a Hydrocyclone in a Recirculating Aquaculture System  

Microsoft Academic Search

This study investigated the performance of a vortex hydrocyclone for solid removal in a recirculating aquaculture system. In a fish- breeding industry, effluent water is mainly disposed by gravity sedimentation. Thus, a large settling tank and a lot of water are needed to purify effluent water. However, this typical method does not show consistent efficiency. In case of low efficiency,

Eunpil Kim; Gul Chang; Jung In Yoon

89

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system is disclosed for an internal combustion engine. The recirculating system is of the type including an exhaust gas recirculation passage for communicating an exhaust tube with an intake tube downstream of a throttle valve disposed therein for recirculating part of exhaust gases from the exhaust tube into the intake tube, and a control valve for

T. Kohama; H. Nohira; H. Obayashi; T. Ozaki

1980-01-01

90

Three-step exhaust gas recirculation control system  

Microsoft Academic Search

An exhaust gas recirculation control system is disclosed for particular application to a diesel engine. The system has an exhaust gas recirculation control valve, and a means for actuating the exhaust gas recirculation control valve, which positions the exhaust gas recirculation control valve selectively and steppedly at one of three states, that are: a first state in which it provides

1981-01-01

91

Closed loop exhaust gas recirculation system  

Microsoft Academic Search

A closed loop exhaust gas recirculation system for an internal combustion engine is described that has an intake system, an exhaust manifold, a throttle disposed within the intake system for controlling air flow therein, a conduit coupling the exhaust manifold to the intake system for supplying exhaust gases back to the intake system for controlling the generation and emission of

Toelle

1979-01-01

92

Impact of water boundary layer diffusion on the nitrification rate of submerged biofilter elements from a recirculating aquaculture system.  

PubMed

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 determine the impact of hydraulic film diffusion on the nitrification rate in a submerged biofilter. Using an experimental batch reactor setup with recirculation, active nitrifying biofilter units from a RAS were exposed to a range of hydraulic flow velocities. Corresponding nitrification rates were measured following ammonium chloride, NH?Cl, spikes and the impact of hydraulic film diffusion was quantified. The nitrification performance of the tested biofilter could be significantly increased by increasing the hydraulic flow velocity in the filter. Area based first order nitrification rate constants ranged from 0.065 m d?¹ to 0.192 m d?¹ for flow velocities between 2.5 m h?¹ and 40 m h?¹ (18 °C). This study documents that hydraulic film diffusion may have a significant impact on the nitrification rate in fixed film biofilters with geometry and hydraulic flows corresponding to our experimental RAS biofilters. The results may thus have practical implications in relation to the design, operational strategy of RAS biofilters and how to optimize TAN removal in fixed film biofilter systems. PMID:22507250

Prehn, Jonas; Waul, Christopher K; Pedersen, Lars-Flemming; Arvin, Erik

2012-07-01

93

Exhaust gas recirculation system for internal combustion engines  

Microsoft Academic Search

In an exhaust gas recirculation system for an internal combustion engine, the flow quantity of exhaust gases recirculated from an exhaust pipe into an induction pipe through a recirculation pipe is controlled in relation to exhaust pressure in the recirculation pipe in accordance with pneumatic pressure defined by a value calculated in a digital computer taking account of negative pressure

T. Ina; H. Kawai; K. Kobashi; T. Kohama; T. Matsui; A. Nishimatsu; H. Nohira

1980-01-01

94

Exhaust gas recirculation system with an auxiliary valve  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine is described that has an exhaust gas recirculation flow control valve provided at a middle position of the exhaust gas recirculation passage, the control valve being operated depending upon comparison between target and actual values of a control parameter with regard to the amount of exhaust gas recirculation. An auxiliary

Tanaka

1980-01-01

95

Exhaust gas recirculation system for internal combustion engines  

Microsoft Academic Search

In an exhaust gas recirculation system for an internal combustion engine, a flow control valve is disposed within a recirculation pipe and operatively connected to a pneumatically operated servomotor to control the flow quantity of exhaust gases through the recirculation pipe, and an orifice is disposed within the recirculation pipe upstream of the valve to form a space between the

T. Inoue; K. Kobashi; T. Kohama; T. Matsui; A. Nishimatsu; K. Oishi

1981-01-01

96

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system is described for an internal combustion engine of the back pressure control type wherein a back pressure chamber formed in a recirculation passage for recirculating exhaust gases is controlled to be substantially at atmospheric pressure by co-operation of a vacuum-operated diaphragm type exhaust gas recirculation control valve and a vacuum control valve which modifies the

N. Nakamura; N. Toyama; T. Baika

1979-01-01

97

Exhaust gas recirculation system for internal combustion engines  

Microsoft Academic Search

An engine exhaust gas recirculation system includes a recirculation gas control valve provided in a gas recirculation passage. The gas recirculation passage is further provided with a restriction and pressure sensors for detecting the pressure drop across the restriction so that the opening of the control valve be adjusted in accordance with the engine operating conditions and with a prestored

1983-01-01

98

Exhaust gas recirculation system for diesel engine  

Microsoft Academic Search

An exhaust gas recirculation control system calculates a target EGR ratio value based upon engine operating parameters and maintains the EGR ratio at the target EGR ratio value. Each time the vehicle travels a predetermined distance, the control system calculates an actual EGR ratio value and corrects the target EGR ratio value to reduce a deviation between the target and

K. Masaki; S. Yasuhara

1984-01-01

99

Pumping effect on particle sizes in a recirculating aquaculture system  

Microsoft Academic Search

Centrifugal pumps are widely used to continuously move water to and from filtration devices in recirculating fish culture systems. The smaller the particle size, particularly below 60–100 ?m, the more difficult and costly it is to remove particulate materials. Minimizing the production of small particles reduces the overall amount of filtration needed. The high rotational speed of a centrifugal pump

J. D McMillan; F. W Wheaton; J. N Hochheimer; J Soares

2003-01-01

100

Rating fixed film nitrifying biofilters used in recirculating aquaculture systems  

Microsoft Academic Search

Predicting the performance of biofilters is an engineering challenge that is critical to both designers and managers. The task is complicated by the wide variety of water quality expectations and environmental conditions displayed by a recirculating aquaculture system (RAS). A myriad of biofilters designs have been generated reflecting approaches of engineers attempting to maximize specific surface area and oxygen transfer

Ronald F. Malone; Timothy J. Pfeiffer

2006-01-01

101

Pressure transducer for exhaust gas recirculation system  

Microsoft Academic Search

A pressure transducer for use in internal combustion engine exhaust gas recirculation systems is disclosed having low inertia moving components for improved response time and a low cost diaphragm mounting arrangement. Upper and lower housing shells define in cooperation with a diaphragm and an upperand lower reaction plates fabricated from light weight plastic, a vacuum chamber, control chamber and a

1983-01-01

102

Control system for use in exhaust gas recirculation system  

Microsoft Academic Search

A control system is described for use in an exhaust gas recirculation system of an internal combustion engine, in which part of exhaust gases is recirculated from an exhaust system to an intake system in an attempt to reduce the amount of harmful components contained in exhaust gases from the engine as well as to prevent lowering of the running

Onaka

1977-01-01

103

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

The disclosed engine exhaust gas recirculation (EGR) system has an EGR passage for recirculating exhaust gases from an exhaust system of an engine back into an intake system thereof downstream of a throttle valve. The EGR passage has a restriction orifice therein and an EGR control valve responsive to a vacuum signal to control the recirculation of exhaust gases through

T. Kohama; H. Obayashi; T. Ozaki; H. Nohira

1979-01-01

104

Common carp (Cyprinus carpio) response to two pieces of music ("Eine Kleine Nachtmusik" and "Romanza") combined with light intensity, using recirculating water system.  

PubMed

The objective of this study was to further investigate the effects of music on fish physiology, bearing in mind available information regarding the involvement of endogenous and exogenous factors in fish farming. Therefore, Cyprinus carpio (50.5 +/- 0.36 g) were reared in a recirculating water system under 80 and 200 lux and subjected to no music at all (control, ambient noise only), 4 h of Mozart's "Eine Kleine Nachtmusik", or 4 h of anonymous "Romanza-Jeux Interdits" for 106 days. Both music treatments resulted in increased growth performance at both light intensities, with Romanza treatment at 200 lux resulting in better growth performance than Mozart treatment. Furthermore, feed efficiency for the Romanza groups was significantly better than for the control. Although no significant music effect was apparent for brain neurotransmitters, lower anterior intestine alkaline protease levels were detected for both music treatments. Taking into consideration the numerous advantages of recirculating water systems, it should be emphasised that fish response to music expresses the results of various physiological and biochemical processes, especially when fish notably respond differently when subjected to two different pieces of music. PMID:19408132

Papoutsoglou, Sofronios E; Karakatsouli, Nafsika; Papoutsoglou, Eustratios S; Vasilikos, Georgios

2010-09-01

105

RECIRCULATION PROCESS OF DEMINERALIZATION WATER TREATMENT PLANT TO REDUCE CONDUCTIVITY LEVEL OF WATER  

E-print Network

Demineralization Water Treatment Plant serves to treat water that has been filtered at the Water Treatment Plant to be "good quality water " with the process of reverse osmosis. The initial design of Demineralization Water Treatment Plant in Pemaron – Bali Gas Turbine is to produce water that have conductivity level in 15 microsimens / cm, which is used for gas turbine cooling water system. At the moment we are planning to install Hydrogen Plant, it turns out this equipment takes raw water with a maximum conductivity of 5 microsimens / cm. So the product of Demineralization Water Treatment Plant is unable. Do a little innovation in production process of Demineralization Water Treatment Plant, namely recirculation, so that it can reduce the value conductivity to below 5 microsimens / cm. From result of laboratory test, it can be concluded that conductivity water after recirculation process is 2 microsimens / cm, thus meet requirement and can be used as raw water for Hydrogen Plant

Kukuh Pambudi; Widi Nurcahyo; K. Adi Dharma; W Tantrawan

106

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine for automotive use is disclosed, wherein a diaphragm-operated recirculation rate control valve adapted to control the exhaust gas recirculation rate depending upon the relationship between the pressure of the exhaust gases passed through an orifice and a vacuum developed in the mixture supply system of the engine is used in

T. Yano; H. Yuzawa

1981-01-01

107

Hydraulics of recirculating well pairs for ground water remediation.  

PubMed

Recirculating well pairs are a proven means of implementing bioremediation and may also be useful for applying other in situ ground water remediation technologies. A bromide tracer test was performed to characterize the hydraulic performance of a recirculating well pair installed at Moffett Field, California. In particular, we estimate two important properties of the recirculating well pair: (1) the fraction of captured water that is recycled between the wells, and (2) the travel-time distribution of ground water in the induced zone of recirculation. We also develop theoretical estimates of these two properties and demonstrate they depend upon a dimensionless pumping rate, denoted xi. The bromide breakthrough curve predicted from theory agrees well with that determined experimentally at Moffett Field. The minimum travel time between the wells is denoted t(min). In theory, t(min) depends inversely on Q, the pumping rate in the recirculating wells, and is proportional to a2, the square of the distance between the wells. Both the experimental and theoretical travel-time distributions indicate that at least half the recirculating water travels between the wells along fast flowpaths (travel time < 2*t(min)). Therefore, when designing recirculating well pairs, engineers should ensure that t(min) will be sufficiently high to allow biologically mediated reactions (or other in situ remediation processes) sufficient time to proceed. PMID:15584301

Cunningham, Jeffrey A; Hoelen, Thomas P; Hopkins, Gary D; Lebrón, Carmen A; Reinhard, Martin

2004-01-01

108

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

Microsoft Academic Search

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

Ying-Feng Lin; Shuh-Ren Jing; Der-Yuan Lee

2003-01-01

109

Membrane biological reactor treatment of a saline backwash flow from a recirculating aquaculture system  

Microsoft Academic Search

A recirculating aquaculture system (RAS) can minimize water use, allowing fish production in regions where water is scarce and also placing the waterborne wastes into a concentrated and relatively small volume of effluent. The RAS effluent generated during clarifier backwash is usually small in volume (possibly 0.2–0.5% of the total recirculating flow when microscreen filters are used) but contains high

Mark J. Sharrer; Yossi Tal; Drew Ferrier; Joseph A. Hankins; Steven T. Summerfelt

2007-01-01

110

Exhaust gas recirculation control system having variable valve lift correcting speed for exhaust gas recirculation valve  

Microsoft Academic Search

An exhaust gas recirculation control system which is adapted to control the valve opening of the exhaust gas recirculation valve so as to minimize the difference between a detected value of the valve opening of the above value and a command value determined as a function of operating conditions of the engine. The valve opening is corrected at a higher

S. Hasegawa; J. Kimura; T. Koumuta; J. Miyake; T. Nakajima

1984-01-01

111

Multi-stage exhaust gas recirculation system  

SciTech Connect

An automotive type exhaust gas recirculation (EGR) system has two modes of operation, a first one that regulates EGR flow at a constant percentage rate as a function of throttle valve position independently of exhaust gas backpressure changes, and a second one that provides a variable percentage rate of flow of EGR gases in response to changes in exhaust gas backpressures, both modes utilizing carburetor ported vacuum modified by an air bleed device as the EGR valve opening force.

Ahrns, D.C.; Rachedi, S.H.

1983-08-16

112

Exhaust gas recirculation control system  

Microsoft Academic Search

A multiple spark plug ignition internal combustion engine is equipped with an EGR control system which consists of an EGR control valve disposed in an EGR passageway connecting an exhaust gas passageway and an intake passageway. The EGR control system is arranged to control EGR rate in accordance with venturi vacuum and in accordance with the exhaust gas pressure in

Aoyama

1979-01-01

113

Exhaust gas recirculation system for internal combustion engines  

Microsoft Academic Search

An exhaust gas recirculation system for internal combustion engines comprises an exhaust gas recirculating passage for tapping engine exhaust gas from an exhaust pipe and feeding back to an engine intake pipe downstream of a throttle valve disposed therein, a control valve for opening and closing the recirculating passage in response to a pressure signal, and a throttle port formed

T. Kohama; H. Nohira; H. Obayashi; T. Ozaki

1980-01-01

114

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine has an exhaust gas recirculation passage, a constant pressure chamber disposed in the exhaust gas recirculation passage, a pressure regulating valve operative in response to the exhaust gas pressure in the constant pressure chamber, a first flow-rate control valve adapted to be actuated by the vacuum regulated by the pressure

Y. Ikuta; M. Matsuo

1981-01-01

115

Internal combustion engine with an exhaust gas recirculation system  

Microsoft Academic Search

Disclosed is an internal combustion engine with an exhaust gas recirculation system. The engine is provided with an exhaust gas recirculation control valve device, a modulator valve device and a vacuum control valve device. The exhaust gas recirculation control valve device communicates an exhaust passage of the engine with an intake passage of the engine and is provided with a

J. Saiki; T. Kumai

1979-01-01

116

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine is disclosed that has an exhaust gas recirculation passage, a constant pressure chamber disposed at an intermediate portion of the exhaust gas recirculation passage, a pressure regulating valve operative in response to the exhaust gas pressure in the constant pressure chamber, a first flow-rate control valve actuated by vacuum regulated

Y. Ikuta; M. Matsuo

1981-01-01

117

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine of the back pressure control type is described which includes a chamber space which is positioned at a middle portion of an exhaust gas recirculation passage and upstream of an exhaust gas recirculation control valve and downstream of an orifice and which is maintained substantially at atmospheric pressure, wherein the

Yuuki

1980-01-01

118

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine is disclosed that has an exhaust gas recirculation control valve of the diaphragm type which controls the opening of an exhaust gas recirculation passage and is actuated by intake vacuum of the engine modified by a vacuum control valve which in turn is actuated by the pressure of exhaust gases

Toyama

1980-01-01

119

Self-calibrating exhaust gas recirculation system  

SciTech Connect

A motor vehicle combustion engine has an exhaust gas recirculation system in which the flow of recirculated exhaust gas is controlled through an orifice having exhaust back pressure on one side and a control pressure on the other as determined by an EGR valve. A pressure transducer compares the control pressure with a reference pressure provided in part by an electromagnetic force to provide an operating pressure for positioning the EGR valve to obtain a control pressure equal to the reference pressure. At engine idle, the EGR valve is closed and the control pressure is equal to the exhaust back pressure. When this condition exists, the electromagnetic force is varied until the reference pressure is substantially equal to the control pressure, the magnitude of the electromagnetic force being a measure of the control pressure at idle and which comprises a calibration value that is stored for use as a reference for controlling exhaust back pressure during other engine operating conditions.

Haka, R.J.; Stoltman, D.D.

1983-08-09

120

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

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

121

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

NASA Technical Reports Server (NTRS)

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.

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

2014-01-01

122

Effects of Elevated Atmospheric Carbon Dioxide Concentrations on Water and Acid Requirements of Soybeans Grown in a Recirculating Hydroponic System.  

National Technical Information Service (NTIS)

Establishing mass budgets of various crop needs, i.e. water and nutrients, in different environments is essential for the Controlled Ecological Life Support System (CELSS). The effects of CO2 (500 and 1000 umol mol (exp -1)) on water and acid use (for pH ...

C. L. Mackowiak, R. M. Wheeler, W. Lowery, J. C. Sager

1990-01-01

123

Integrated dynamic aquaculture and wastewater treatment modelling for recirculating aquaculture systems  

Microsoft Academic Search

Recirculating aquaculture systems (RAS) in land based fish tanks, where the fish tank effluent is biologically treated and then recirculated back to the fish tanks, offers a possibility for large scale ecologically sustainable fish production. In order to fully exploit the advantages of RAS, however, the water exchange should be as small as possible. This implies strong demands on the

Torsten E. I. Wik; Björn T. Lindén; Per I. Wramner

2009-01-01

124

Integrated Dynamic Aquaculture and Wastewater Treatment Modelling for Recirculating Aquaculture Systems  

Microsoft Academic Search

Recirculating aquaculture systems (RAS) in land based sh tanks, where the sh tank euen t is biologically treated and then recirculated back to the sh tanks, of- fers a possibility for large scale ecologically sustainable sh production. In order to fully exploit the advantages of RAS, however, the water exchange should be as small as possible. This implies strong demands

Torsten E. I. Wika; Bjorn T. Lind

125

Effects of feedstock, airflow rate, and recirculation ratio on performance of composting systems with air recirculation.  

PubMed

The thermodynamics, kinetics, and energy use of composting systems with air recirculation were determined for feedstocks comprising paper mill sludge and biosolids. Results were developed by simulating the composting system using a two-dimensional finite difference numerical model. Incorporated into the simulation model was independent regulation of temperature and oxygen using a closed loop feedback control system with a two-stage fan setting. Results showed that at low airflows and high recirculation ratios, heat removal by the exhaust gas was insufficient to maintain set point temperatures with the result that process temperatures increased and eventually limited the reaction rate. Types of feedstock, magnitude of airflow and recirculation ratio all affected the energy use of the system. Although recirculation leads to high energy use, it can produce high quality compost by having a temperature gradient of less than 2 degrees C across the bed. PMID:15963715

Ekinci, K; Keener, H M; Akbolat, D

2006-05-01

126

Use of Treated Municipal Wastewater as Power Plant Cooling System Makeup Water: Tertiary Treatment versus Expanded Chemical Regimen for Recirculating Water Quality Management  

SciTech Connect

Treated municipal wastewater is a common, widely available alternative source of cooling water for thermoelectric power plants across the U.S. However, the biodegradable organic matter, ammonia-nitrogen, carbonate and phosphates in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, respectively. The overall objective of this study was to evaluate the benefits and life cycle costs of implementing tertiary treatment of secondary treated municipal wastewater prior to use in recirculating cooling systems. The study comprised bench- and pilot-scale experimental studies with three different tertiary treated municipal wastewaters, and life cycle costing and environmental analyses of various tertiary treatment schemes. Sustainability factors and metrics for reuse of treated wastewater in power plant cooling systems were also evaluated. The three tertiary treated wastewaters studied were: secondary treated municipal wastewater subjected to acid addition for pH control (MWW_pH); secondary treated municipal wastewater subjected to nitrification and sand filtration (MWW_NF); and secondary treated municipal wastewater subjected nitrification, sand filtration, and GAC adsorption (MWW_NFG). Tertiary treatment was determined to be essential to achieve appropriate corrosion, scaling, and biofouling control for use of secondary treated municipal wastewater in power plant cooling systems. The ability to control scaling, in particular, was found to be significantly enhanced with tertiary treated wastewater compared to secondary treated wastewater. MWW_pH treated water (adjustment to pH 7.8) was effective in reducing scale formation, but increased corrosion and the amount of biocide required to achieve appropriate biofouling control. Corrosion could be adequately controlled with tolytriazole addition (4-5 ppm TTA), however, which was the case for all of the tertiary treated waters. For MWW_NF treated water, the removal of ammonia by nitrification helped to reduce the corrosivity and biocide demand. Also, the lower pH and alkalinity resulting from nitrification reduced the scaling to an acceptable level, without the addition of anti-scalant chemicals. Additional GAC adsorption treatment, MWW_NFG, yielded no net benefit. Removal of organic matter resulted in pitting corrosion in copper and cupronickel alloys. Negligible improvement was observed in scaling control and biofouling control. For all of the tertiary treatments, biofouling control was achievable, and most effectively with pre-formed monochloramine (2-3 ppm) in comparison with NaOCl and ClO2. Life cycle cost (LCC) analyses were performed for the tertiary treatment systems studied experimentally and for several other treatment options. A public domain conceptual costing tool (LC3 model) was developed for this purpose. MWW_SF (lime softening and sand filtration) and MWW_NF were the most cost-effective treatment options among the tertiary treatment alternatives considered because of the higher effluent quality with moderate infrastructure costs and the relatively low doses of conditioning chemicals required. Life cycle inventory (LCI) analysis along with integration of external costs of emissions with direct costs was performed to evaluate relative emissions to the environment and external costs associated with construction and operation of tertiary treatment alternatives. Integrated LCI and LCC analysis indicated that three-tiered treatment alternatives such as MWW_NSF and MWW_NFG, with regular chemical addition for treatment and conditioning and/or regeneration, tend to increase the impact costs and in turn the overall costs of tertiary treatment. River water supply and MWW_F alternatives with a single step of tertiary treatment were associated with lower impact costs, but the contribution of impact costs to overall annual costs was higher than all other treatment alternatives. MWW_NF and MWW_SF alternatives exhibited moderate external impact costs with moderate infrastructure and chemical conditioner dosing, which makes them (especially

David Dzombak; Radisav Vidic; Amy Landis

2012-06-30

127

Exhaust-gas-recirculation system for use in diesel engines  

Microsoft Academic Search

An exhaust-gas-recirculation system is disclosed for use in diesel engines, having a valve member adapted to control the flow rate of the exhaust gas recirculated from the exhaust pipe to the intake pipe of the diesel engine. The exhaust-gas-recirculation system has a fly-weight rotatable in synchronization with the engine to produce a centrifugal force, a governor sleeve displaceable in response

K. Matsui; T. Miyazaki; E. Nomura; H. Sami; T. Ueda

1981-01-01

128

Exhaust gas recirculation system for an internal combustion engine  

DOEpatents

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.

Wu, Ko-Jen

2013-05-21

129

Exhaust gas recirculation system for a diesel engine  

Microsoft Academic Search

An exhaust gas recirculation system is provided for reducing the content of oxides of nitrogen in the exhaust of a diesel engine. The system is effective in recirculating variable amounts of exhaust gas back through the engine in relation to engine load by being operatively controlled in response to predetermined settings of the engine's fuel supply system.

R. A. Kern; C. L. McClung; J. R. Turner

1977-01-01

130

Internal combustion engine with an exhaust gas recirculation system  

Microsoft Academic Search

Disclosed is an internal combustion engine with an exhaust gas recirculation system. The engine is provided with a carburetor which includes a primary system and a secondary system. The recirculated exhaust gas is supplied to the intake passage via an exhaust gas supply pipe which is disposed at a position downstream of the carburetor. The top end of the exhaust

Saiki

1980-01-01

131

Anammox bacteria in different compartments of recirculating aquaculture systems.  

PubMed

Strict environmental restrictions force the aquaculture industry to guarantee optimal water quality for fish production in a sustainable manner. The implementation of anammox (anaerobic ammonium oxidation) in biofilters would result in the conversion of both ammonium and nitrite (both toxic to aquatic animals) into harmless dinitrogen gas. Both marine and freshwater aquaculture systems contain populations of anammox bacteria. These bacteria are also present in the faeces of freshwater and marine fish. Interestingly, a new planctomycete species appears to be present in these recirculation systems too. Further exploitation of anammox bacteria in different compartments of aquaculture systems can lead to a more environmentally friendly aquaculture practice. PMID:22103532

van Kessel, Maartje A H J; Harhangi, Harry R; Flik, Gert; Jetten, Mike S M; Klaren, Peter H M; Op den Camp, Huub J M

2011-12-01

132

Internal combustion engine having exhaust gas recirculation system  

Microsoft Academic Search

An internal combustion engine has an exhaust gas recirculation system including a recirculation valve for controlling the amount of exhaust gas returned to the intake system. The position or opening of the valve is controlled to a desired position in accordance with a memory in a memory device storing desired valve positions under various combinations of the engine load and

K. Iida; K. Okazaki; Y. Yada

1983-01-01

133

Exhaust gas recirculation system having electrical control means  

Microsoft Academic Search

Exhaust gas recirculation system including an intake pressure operated control valve for controlling the amount of exhaust gas recirculated to the intake system and a suction pressure adjusting valve of a duty factor solenoid type for determining the suction pressure applied to the control valve. A control circuit is provided for applying an operating signal to the pressure adjusting valve.

1984-01-01

134

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

In an exhaust gas recirculation system for an internal combustion engine having an intake manifold in which a throttle valve is disposed and an exhaust gas conduit provided with a particle trap for accumulatively catching particles entrained by exhaust gas discharged from the engine, a control valve apparatus which is disposed in a recirculation passage and connected to the intake

K. Dozono; Y. Hasegawa

1983-01-01

135

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine employs a first control valve in an exhaust gas introduction passageway, a second control valve in an air conduit connecting the engine intake passage to atmosphere, and a regulating valve responsive to differential vacuum intensities for operating vacuum-responsive actuators for the control valves. A recirculation stop valve vents to atmosphere

Y. Abe; O. Gotoh; A. Takagi

1982-01-01

136

Flow control valve for exhaust gas recirculation system  

Microsoft Academic Search

A flow control valve is provided for use in an exhaust gas recirculation system of an internal combustion engine, whereby a constant flow of the recirculating gas may be maintained. The valve comprises a first and second valve chamber separated by a flow orifice, with a valve body for opening and closing of the flow orifice. Exhaust gas entering the

K. Goto; R. Mitsui

1975-01-01

137

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine wherein a fixed restriction, a pressure chamber and a pressure control valve are arranged in the order named in an exhaust gas recirculation passage and the pressure control valve is controlled in such a way that the pressure in the pressure chamber may be maintained equal to the combined pressure

Yorioka

1980-01-01

138

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine of the back pressure control type is described which provides, by a vacuum-operated control valve, a pressure chamber of substantially constant and nearly atmospheric pressure at a middle portion of an exhaust gas recirculation passage, and a thermostatic control means incorporated in a vacuum passage which supplies control vacuum to

T. Taifu; N. Toyama

1980-01-01

139

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system for reducing nitrogen oxide emissions from automotive internal combustion engines is described in which the rate or amount of exhaust gases recirculated into the intake manifold of the engine is controlled in relation to the operating conditions of the engine. A device for supplying secondary air into the exhaust is also provided. An exhaust gas

Hayashi

1974-01-01

140

Exhaust gas recirculation system for internal combustion engines  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine employs a vacuum actuator for a control valve in the exhaust gas recirculation passageway. A suction conduit to the actuator contains a magnetic valve for venting the suction conduit to atmosphere. The operating means for the magnetic valve includes a vacuum switch responsive to suction pressure in the engine intake

M. Obata; N. Satoh

1982-01-01

141

Exhaust gas recirculation control system for a diesel engine  

Microsoft Academic Search

An exhaust gas recirculation control system is disclosed such that the throttle valve is controlled by two vacuum actuators through three stages of fully-opened, half-opened, and fully closed positions, in addition to the control of the exhaust gas recirculation control valve, in accordance with the engine operating conditions including engine load. The egr valve is fully closed under a heavy

Y. Kimura; M. Shiobara; Y. Yoshiba

1983-01-01

142

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

Microsoft Academic Search

Common “off-flavors” in fish cultured in recirculating aquaculture systems (RAS) 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 RAS at relatively low doses to break refractory organic molecules (i.e., reducing color), microflocculate fine particulate matter (i.e., increasing solids removal), and oxidize nitrite to nitrate,

Kevin K. Schrader; John W. Davidson; Agnes M. Rimando; Steven T. Summerfelt

2010-01-01

143

Microparticles in recirculating aquaculture systems: determination of particle density by density gradient centrifugation  

Microsoft Academic Search

Solid particulates in aquaculture waters are often separated from the culture water on a basis of density. The character and density of particles in such systems are not well defined. A method of determining the density of organic-based solids in aquaculture systems using density gradient centrifugation is demonstrated. The density of the two main particle fractions in one cold-water recirculating

R. N Patterson; K. C Watts; T. A Gill

2003-01-01

144

The design and construction of an open channel recirculating water tank for the study of biological hydrocarbons  

E-print Network

This project chronicles the design and construction of a small scale recirculating water tank for the purpose of studying biological hydrodynamics. Currently available systems were analyzed and studied prior to developing ...

Hennessey, Thomas V. (Thomas Vincent), III

2005-01-01

145

Continuous hydroponic wheat production using a recirculating system  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

146

A BIOECONOMIC MODEL OF RECIRCULATING SHRIMP PRODUCTION SYSTEMS.  

E-print Network

??To prevent disease outbreaks and increase competitiveness of U.S. shrimp products, U.S. aquaculture researchers have developed super-intensive, bio-secure, recirculating shrimp production systems since the early… (more)

ZHOU, XIA Vivian

2007-01-01

147

Method of detecting a fault of an exhaust gas recirculation system  

Microsoft Academic Search

This patent describes a method of detecting a fault of an exhaust gas recirculation system of an internal combustion engine, wherein a temperature relating to a temperature of the exhaust gas recirculating through the exhaust gas recirculation system is detected when the exhaust gas recirculation system is in a condition in which the system should be operated to return part

T. Hashimoto; A. Takahashi; T. Imaizuma; S. Saito; H. Tanaka; T Jimbo

1989-01-01

148

Exhaust gas recirculation control system having a function of automatically correcting detected zero opening value of exhaust gas recirculation valve  

Microsoft Academic Search

An exhaust gas recirculation control system is disclosed which is adapted to control the valve opening of the exhaust gas recirculation valve so as to minimize the difference between a detected value of the valve opening of the above valve and a command value read from a memory as a function of operating condition of the engine. The system includes

S. Hasegawa; Y. Otobe; A. Yamato

1983-01-01

149

Performance of a Water Recirculation Loop Maintenance Device and Process for the Advanced Spacesuit Water Membrane Evaporator  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

150

Design and Evaluation of a Water Recirculation Loop Maintenance Device for the Advanced Spacesuit Water Membrane Evaporator  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

151

THE PRESENCE OF BACTERIAL PATHOGENS IN RECIRCULATING AQUACULTURE SYSTEM BIOFILMS AND THEIR RESPONSE TO VARIOUS SANITIZERS  

Microsoft Academic Search

ABSTRACT Recirculating aquaculture offers a prospect for successful fish farming, but this form of aquaculture presents a great potential for pathogenic microorganisms,to become established in the system through the formation of biofilms. Biofilms are capable of forming on all aquaculture system components, incorporating the various microflora present in the water. Pathogenic microorganisms,released from the biofilms are capable of causing recurring

Robin K. King

152

Growth and survival of juvenile cobia, Rachycentron canadum, at different salinities in a recirculating aquaculture system  

Microsoft Academic Search

Cobia (Rachycentron canadum) is an emerging aquaculture candidate for both offshore cage culture and land-based systems such as recirculating aquaculture systems. The ability to grow cobia at salinities other than oceanic (?34 ppt) could present culturists with additional production opportunities with this species. Culture at low salinities could also reduce the incidence of disease and simplify water management. In two

Matthew J. Resley; Kenneth A. Webb; G. Joan Holt

2006-01-01

153

Nephrocalcinosis in Nile Tilapia from a Recirculation Aquaculture System: A Case Report  

Microsoft Academic Search

Nile tilapia Oreochromis niloticus were presented to the Fish Disease Diagnostic Laboratory with the complaint of chronic low-level mortalities in a recirculation aquaculture system. Microscopic examination of kidneys revealed moderate to severe nephrocalcinosis. Salient information from the case history was the utilization of agricultural-grade lime (calcium carbonate) to maintain alkalinity in the water of the culture system for the 4

Chun-Yao Chen; Gregory A. Wooster; Rodman G. Getchell; Paul R. Bowser; Michael B. Timmons

2001-01-01

154

New developments in recirculating aquaculture systems in Europe: A perspective on environmental sustainability  

Microsoft Academic Search

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 management and nutrient recycling. RAS makes intensive fish production compatible with environmental sustainability. This review aims to summarize the

C. I. M. Martins; E. H. Eding; M. C. J. Verdegem; L. T. N. Heinsbroek; O. Schneider; J. P. Blancheton; E. Roque d’Orbcastel; J. A. J. Verreth

2010-01-01

155

Efficacy of Hydrogen Peroxide in Marine Recirculating Aquaculture Systems Holding Summer Flounder, Paralichthys dentatus  

Microsoft Academic Search

The effect of continuous dosing of hydrogen peroxide to a marine recirculating aquaculture system holding summer flounder was examined. Hydrogen peroxide is a strong oxidizing agent that may affect many chemical and biological processes. Results indicate that continuous dosing of hydrogen peroxide at the level tested is not an effective method to improve water quality in marine systems.

David E. Mowry; Michael H. Schwarz; Kathleen H. Hartman; Michael L. Jahncke; Stephen A. Smith

2005-01-01

156

Recirculating Molten Metal Supply System And Method  

DOEpatents

The melter furnace includes a heating chamber (16), a pump chamber (18), a degassing chamber (20), and a filter chamber (22). The pump chamber (18) is located adjacent the heating chamber (16) and houses a molten metal pump (30). The degassing chamber (20) is located adjacent and in fluid communication with the pump chamber (18), and houses a degassing mechanism (36). The filter chamber (22) is located adjacent and in fluid communication with the degassing chamber (20). The filter chamber (22) includes a molten metal filter (38). The melter furnace (12) is used to supply molten metal to an externally located holder furnace (14), which then recirculates molten metal back to the melter furnace (12).

Kinosz, Michael J. (Apollo, PA); Meyer, Thomas N. (Murrysville, PA)

2003-07-01

157

Closed recirculating system for shrimp-mollusk polyculture  

NASA Astrophysics Data System (ADS)

This paper deals with a new system of aquaculture, i.e., a closed recirculating system for shrimp-mollusk polyculture. The culture system consisted of several shrimp ponds, a mollusk water-purifying pond and a reservoir. During the production cycle, water circulated between the shrimp and mollusk ponds, and the reservoir compensated for water loss from seepage and evaporation. Constricted tagelus, Sinonovacula constricta, was selected as the cultured mollusk, and Pacific white shrimp, Litopenaeus vannamei, as the cultured shrimp. The main managing measures during the production cycle were: setting and using the aerators; introducting the probiotic products timely into the shrimp ponds; adopting a “pen-closing” method for controlling shrimp viral epidemics; setting the flow diversion barriers in the mollusk pond to keep the circulating water flowing through the pond along a sine-like curve and serve as substrate for biofilm; no direct feeding was necessary for the cultured mollusk until the co-cultured shrimp was harvested; natural foods in the water from the shrimp ponds was used for their foods. Two sets of the system were used in the experiment in 2002 and satisfactory results were achieved. The average yield of the shrimp was 11 943.5 kg/hm2, and that of the mollusk was 16 965 kg/hm2. After converting the mollusk yield into shrimp yield at their market price ratio, the food coefficient of the entire system averaged at as low as 0.81. The water quality in the ponds was maintained at a desirable level and no viral epidemics were discovered during the production cycle.

Wu, Xiongfei; Zhao, Zhidong; Li, Deshang; Chang, Kangmei; Tong, Zhuanshang; Si, Liegang; Xu, Kaichong; Ge, Bailin

2005-12-01

158

Exhaust gas recirculation system of an internal combustion engine  

Microsoft Academic Search

Disclosed is an exhaust gas recirculation system of an internal combustion engine for high altitude use. The system includes a feedback control valve for controlling the amount of exhaust gas fed back to an intake passage, and a compensating device for decreasing a set pressure level of the feedback control valve, above which set level the feedback control valve is

K. Katoh; T. Ogita

1980-01-01

159

An Inexpensive Recirculating Aquaculture System with Multiple Use Capabilities.  

ERIC Educational Resources Information Center

Describes the construction of an inexpensive recirculating aquaculture system that can hold up to 46 pounds of fish, invertebrates, and mussels for classroom use. The system is versatile, requires little maintenance, and can be used for both teaching and research purposes. (WRM)

Scurlock, Gerald Don, Jr.; Cook, S. Bradford; Scurlock, Carrie Ann

1999-01-01

160

Exergetic performance analysis of a recirculating aquaculture system  

Microsoft Academic Search

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

Haydar Kucuk; Adnan Midilli; Atilla Özdemir; Eyüp Çakmak; Ibrahim Dincer

2010-01-01

161

Exhaust gas recirculation system of a motor vehicle  

Microsoft Academic Search

An improvement for an exhaust gas recirculation (EGR) system of a motor vehicle is described. The system consists of: (1) a diaphragm type EGR valve mounted on an EGR pipe which connects the exhaust manifold and the intake manifold; (2) an opening path for air from the atmosphere diverged from a connecting pipe which connects the diaphragm chamber of the

Hamanishi

1977-01-01

162

Exhaust gas recirculation system in an internal combustion engine  

Microsoft Academic Search

This application discloses an exhaust gas recirculation system in an internal combustion engine. The system is comprise of: (1) an EGR pipe which interconnects an exhaust pipe and an intake pipe of the engine; (2) an EGR valve mounted of the EFR pipe; (3) an EGR cooler mounted on the EGR pipe upstream of said EGR valve; (4) a by-pass

Nagano

1979-01-01

163

Ozone Application in Recirculating Aquaculture System: An Overview  

Microsoft Academic Search

In recirculating aquaculture systems (RAS), particulates (including feces, uneaten feed, bacteria, and algae) can cause several problems, in that they may harbor pathogens, can physically irritate the fish, and upon decomposition, release ammonia and consume oxygen. Mechanical filters, foam fractionators, and other engineered devices are used to remove particles quickly from aquaculture systems, in order to improve fish health and

Alex Augusto Gonçalves; Graham A. Gagnon

2011-01-01

164

The accumulation of substances in Recirculating Aquaculture Systems (RAS) affects embryonic and larval development in common carp Cyprinus carpio  

Microsoft Academic Search

The accumulation of substances in Recirculating Aquaculture Systems (RAS) may impair the growth and welfare of fish. To test the severity of contaminants accumulated in RAS, early-life stages of fish were used. Ultrafiltered water from two Recirculating Aquaculture Systems (RAS), one RAS with a high accumulation of substances (water exchange rate 30 L\\/kg feed\\/day) and one RAS with a low accumulation

Catarina I. M. Martins; Marco G. Pistrin; Stephan S. W. Ende; Ep H. Eding; Johan A. J. Verreth

2009-01-01

165

Exhaust gas recirculation control system for a diesel engine  

SciTech Connect

An exhaust gas recirculation control system is disclosed such that the throttle valve is controlled by two vacuum actuators through three stages of fully-opened, half-opened, and fully closed positions, in addition to the control of the exhaust gas recirculation control valve, in accordance with the engine operating conditions including engine load. The egr valve is fully closed under a heavy engine load and fully opened under a medium and light engine load, and the throttle valve is fully opened under a heavy engine load, half opened under a medium engine load, and fully closed under a light engine load, under due consideration of engine speed.

Kimura, Y.; Shiobara, M.; Yoshiba, Y.

1983-06-21

166

Design of a computerized, temperature-controlled, recirculating aquaria system  

USGS Publications Warehouse

We built a recirculating aquaria system with computerized temperature control to maintain static temperatures, increase temperatures 1 ??C/day, and maintain diel temperature fluctuations up to 10 ??C. A LabVIEW program compared the temperature recorded by thermocouples in fish tanks to a desired set temperature and then calculated the amount of hot or cold water to add to tanks to reach or maintain the desired temperature. Intellifaucet?? three-way mixing valves controlled temperature of the input water and ensured that all fish tanks had the same turnover rate. The system was analyzed over a period of 50 days and was fully functional for 96% of that time. Six different temperature treatments were run simultaneously in 18, 72 L fish tanks and temperatures stayed within 0.5 ??C of set temperature. We used the system to determine the upper temperature tolerance of fishes, but it could be used in aquaculture, ecological studies, or other aquatic work where temperature control is required. ?? 2005 Elsevier B.V. All rights reserved.

Widmer, A.M.; Carveth, C.J.; Keffler, J.W.; Bonar, S.A.

2006-01-01

167

The use of ozone in a high density recirculation system for rotifers  

Microsoft Academic Search

The use of ozone in the effluent treatment of a closed recirculation system for rotifers resulted in a significant improvement of rotifer production and water quality. Compared to a control treatment, the rotifer culture exposed to ozone did not only support a higher rotifer biomass (16000 vs. 8000 rotifers ml?1), it also allowed a prolongation of the culture period for

G Suantika; P Dhert; G Rombaut; J Vandenberghe; T De Wolf; P Sorgeloos

2001-01-01

168

Membrane Filtration Coupled with Chemical Precipitation to Treat Recirculating Aquaculture System Effluents  

Microsoft Academic Search

Effluents from recirculating aquaculture systems (RAS) contain high concentrations of nitrogen and phosphorous wastes and thus of- ten require proper treatment to prevent potential detrimental impacts on receiving water bodies. The purpose of this study was to evaluate the feasibility of membrane filtration coupled with chemical precip- itation as a pretreatment step with emphasis on phosphorus removal from RAS effluents.

Ling Yang; Hongde Zhou; Richard Moccia

2006-01-01

169

A conceptual, stoichiometry-based model for single-sludge denitrification in recirculating aquaculture systems  

Microsoft Academic Search

In the near future, the discharge of nitrate from recirculating aquaculture systems (RAS) to receiving water bodies is expected to be constrained by environmental regulations. Following wastewater treatment terminology, nitrate removal that makes use of the organic solid wastes generated within the RAS as the energy source for denitrification, may be termed ‘single-sludge denitrification’. In this approach, the costs associated

Sivan Klas; Noam Mozes; Ori Lahav

2006-01-01

170

Diesel engine exhaust gas recirculation system with greater atmospheric pressure compensation at low engine load  

Microsoft Academic Search

An exhaust gas recirculation system is described for a diesel engine for a vehicle utilizing an air intake system and an exhaust system including: (a) an exhaust gas recirculation passage a downstream and of which is connected to the exhaust system and an upstream end of which is connected to the air intake system, so as to recirculate exhaust gas

M. Kawagoe; O. Hishinuma

1986-01-01

171

Fish Health Management Considerations in Recirculating Aquaculture systems -Part 3: General  

E-print Network

Cir 122 Fish Health Management Considerations in Recirculating Aquaculture systems -Part 3: General a system, consult with an aquaculture specialist or an expert on recirculating systems. #12;2 All important Introduction Both the popularity and use of recirculating systems have increased, and these systems are now

Watson, Craig A.

172

Diesel engine exhaust gas recirculation and intake air flow control system  

Microsoft Academic Search

In a diesel engine which includes an air intake system, an exhaust system, and an exhaust gas recirculation passage which recirculates part of the exhaust gases produced by the engine from the exhaust system to the air intake system, a control system for the recirculation of exhaust gases and the flow of intake air, having an intake air flow control

K. Hiyama; T. Ueda

1982-01-01

173

Exhaust gas recirculation system for automatic transmission vehicle  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine is described which consists of an automatic transmission which has gear ratios and shifts between the gear ratios in accordance with selected shift patterns including an economy pattern in which upshift between successive ones of gear ratios occurs at first corresponding predetermined vehicle speeds and a power pattern in which

Y. Abe; T. Okano; T. Omori; M. Kawamoto

1987-01-01

174

Vacuum regulation valve in an exhaust gas recirculation system  

Microsoft Academic Search

The vacuum regulation valve operable to regulate the vacuum in the vacuum line of an exhaust gas recirculation system, includes a compact construction and a buffer means which is effective to eliminate the clattering sounds inherent in the conventional vacuum regulation valve.

M. Washio; T. Harada

1978-01-01

175

Integrated idle air and exhaust gas recirculation system  

Microsoft Academic Search

An integrated idle air and exhaust gas recirculation control system for use on an internal combustion engine. A control valve assembly comprising a base having a central chamber therin and inlet means for the introduction of idle air and exhaust gas to the central chamber and an outlet opening for the supply of the idle air and exhaust gas to

McKay

1991-01-01

176

Exhaust gas recirculation system for a V-type engine  

Microsoft Academic Search

This patent describes an exhaust gas recirculation system for a V-type engine having a pair of cylinder banks arranged at an angle to each other on opposite sides of a crankshaft, each cylinder bank having cylinders therein and an intake passage being separately provided for each cylinder. The improvement described here comprises that the intake passages have respective proximate portions

M. Choushi; H. Ishimi

1986-01-01

177

Exhaust gas recirculation system for an automotive engine  

Microsoft Academic Search

The invention discloses an exhaust gas recirculation system for an automotive engine in which that portion of the exhaust stream is selectively withdrawn which contains the major amount of undesirable ingredients. The portion of gas from each cylinder is received in a common mixing chamber and thereafter passed to the inlet side of the engine for mixing with fresh charge

K. S. Virk; H. E. Leikkanen

1979-01-01

178

Exhaust gas recirculation system for an internal combustion engine  

Microsoft Academic Search

In an internal combustion engine having an intake passage provided therein with a throttle valve for controlling intake flow of air or an air-fuel mixture passing therethrough toward engine cylinders and an exhaust passage, an exhaust gas recirculation system comprises first means for conducting a portion of the exhaust gases from the exhaust passage into the intake passage downstream of

Higashi

1984-01-01

179

Anaerobic digestion of sludge from intensive recirculating aquaculture systems: Review  

Microsoft Academic Search

Intensive recirculating aquaculture systems (RAS) produce high volumes of biosolid waste which is a potential source of pollution if not properly treated. A reduction in sludge-mass would therefore minimize the potential environmental hazard and economic burden stemming from its disposal. Recently, anaerobic digestion was suggested as an alternative to aquaculture sludge digestion and stabilization in RAS. This practice results not

Natella Mirzoyan; Yossi Tal; Amit Gross

2010-01-01

180

Geochemical Effects of Increased Production on Recirculated Process Water at the Kiirunavaara Iron Mine, Northern Sweden  

Microsoft Academic Search

Understanding process water characteristics and variations is important for ensuring high quality processing of iron ore.\\u000a Large amounts of water are used during refinement, and the water is often recirculated to save energy. Water quality is important\\u000a for processes such as flotation and agglomeration but recirculation of process water and changes in production can alter water\\u000a quality significantly. This study

Magnus Westerstrand; Björn Öhlander

181

Powdered activated carbon for fouling reduction of a membrane in a pilot-scale recirculating aquaculture system  

Microsoft Academic Search

Recirculating aquaculture systems (RAS) are essential for the reduction in fresh water usage as well as the discharge of nutrients along with aquaculture effluents. A RAS consisting of an anoxic reactor, a membrane bioreactor (MBR) and a UV-disinfection unit was used to process 10,000 L\\/d of aquaculture effluent providing high-quality treated water for recirculation to a Barramundi fish culture. The

V. Jegatheesan; N. Senaratne; C. Steicke; Seung-Hyun Kim

2009-01-01

182

Kinetics of electro-oxidation of ammonia-N, nitrites and COD from a recirculating aquaculture saline water system using BDD anodes.  

PubMed

The viability of the electro-oxidation technology provided with boron doped diamond (BDD) electrodes for the treatment and reuse of the seawater used in a Recirculating Aquaculture System (RAS) was evaluated in this work. The influence of the applied current density (5-50 A m(-2)) in the removal of Total Ammonia Nitrogen (TAN), nitrite and chemical oxygen demand (COD) was analyzed observing that complete TAN removal together with important reductions of the other considered contaminants could be achieved, thus meeting the requirements for reuse of seawater in RAS systems. TAN removal, mainly due to an indirect oxidation mechanism was described by a second order kinetics while COD and nitrite removal followed zero-th order kinetics. The values of the kinetic constants for the anodic oxidation of each compound were obtained as a function of the applied current density (k(TAN) = 7.86 × 10(-5) · exp(6.30 × 10(-2) J); kNO2 = 3.43 × 10(-2) J; k(COD) = 1.35 × 10(-2) J). The formation of free chlorine and oxidation by-products, i.e., trihalomethanes (THMs) was followed along the electro-oxidation process. Although a maximum concentration of 1.7 mg l(-1) of total trihalomethanes was detected an integrated process combining electrochemical oxidation in order to eliminate TAN, nitrite and COD and adsorption onto activated carbon to remove the residual chlorine and THMs is proposed, as an efficient alternative to treat and reuse the seawater in fish culture systems. Finally, the energy consumption of the treatment has been evaluated. PMID:20832837

Díaz, V; Ibáñez, R; Gómez, P; Urtiaga, A M; Ortiz, I

2011-01-01

183

Ozone (o3) efficacy on reduction of phytophthora capsici in recirculated horticultural irrigation water  

E-print Network

Microorganisms that cause plant disease have been isolated in recirculated irrigation water and increase the risks of disease incidence in horticultural operations. Ozone is an effective oxidizer used to disinfect drinking water supplies and treat...

McDonald, Garry Vernon

2009-05-15

184

Potential and limitations of ozone for the removal of ammonia, nitrite, and yellow substances in marine recirculating aquaculture systems  

Microsoft Academic Search

The high levels of water-reuse in intensive recirculating aquaculture systems (RAS) require an effective water treatment in order to maintain good water quality. In order to reveal the potential and limitations of ozonation for water quality improvement in marine RAS, we tested ozone's ability to remove nitrite, ammonia, yellow substances and total bacterial biomass in seawater, considering aspects such as

J. P. Schroeder; P. L. Croot; B. Von Dewitz; U. Waller; R. Hanel

2011-01-01

185

TRACG Simulation of Drywell Gas Recirculation System in ESBWR  

Microsoft Academic Search

This paper presents the results of a parametric study on the mitigating effects of the Drywell Gas Recirculation System (DGRS) in ESBWR during postulated LOCA and severe accidents. The post-accident containment pressure depends on the sum of the partial pressure from non-condensable gases and partial steam pressure inside the wet-well airspace. Results of parametric studies show that, with the activation

Yee K. Cheung; Atambir S. Rao

2002-01-01

186

Ammonia Conversion Characteristics in a Closed Recirculating Aquaculture System  

Microsoft Academic Search

Nitrification and denitrification were commonly used in the recirculating aquaculture system (RAS) to decrease the ammonia and nitrate concentration. The variation characteristics of nitrogenous compounds and microbiology in a closed RAS were studied with gradually increasing ammonia-nitrogen (NH4 +-N) concentration. The NH4 +-N was completely converted into nitrite nitrogen (NO2 --N) in 46 days, but the NO2 --N raised slowly

Guang-Yu Wang; Ji-xian Yang; Fang Ma; Lei Chen; Wei-Guo Li; Jingbo Guo

2009-01-01

187

Growth Performance of Walleye, Sander vitreus, in Recirculating Aquaculture Systems  

Microsoft Academic Search

Walleye, Sander vitreus, fingerlings were reared in two recirculating aquaculture systems (RAS) to compare growth performance at three stocking densities (11, 24, and 36 kg\\/m). There was a negative relationship between increasing stocking density and growth calculated as percent body weight (BW) gain\\/day, total length (mm) gain\\/day, specific growth rate (SGR) of weight (%\\/day), and SGR of total length (%\\/day).

Chester B. Zarnoch; Martin P. Schreibman; Richard T. Colesante; Michael B. Timmons

2010-01-01

188

Exhaust gas recirculation system controlled by a microcomputer for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation system controlled by a microcomputer for an internal combustion engine is comprised of a pressure sensor for measuring the pressure of the exhaust gas downstream of an orifice disposed in the exhaust gas recirculation passage, a microcomputer for electrically controlling an electromagnetic valve which fluidly controls an exhaust gas recirculation control valve arranged in the exhaust

T. Yano; H. Yuzawa

1981-01-01

189

Low-Dose Hydrogen Peroxide Application in Closed Recirculating Aquaculture Systems  

Microsoft Academic Search

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 for a period of 3 months. The organic and nitrogenous loadings of the systems differed fourfold between the

Lars-Flemming Pedersen; Christopher M. Good; Per B. Pedersen

2012-01-01

190

Integration of western king prawn ( Penaeus latisulcatus Kishinouye, 1896) and green seaweed ( Ulva lactuca Linnaeus, 1753) in a closed recirculating aquaculture system  

Microsoft Academic Search

Integrating recirculating aquaculture systems with seaweeds is one of the strategies that can minimise wastes and risk of disease outbreaks. This study investigated the effect of integrating green seaweed (Ulva lactuca) with western king prawns (Penaeus latisulcatus) at varying stocking densities on the water quality, nutrient conversion rates and nutrient budget under closed recirculating culture system. The experiment was conducted

Le Van Khoi; Ravi Fotedar

191

Diagnosing system for an exhaust gas recirculation system of an automotive engine  

Microsoft Academic Search

This patent describes a diagnosing system for an exhaust gas recirculation system having an EGR passage communicating an exhaust pipe of an engine with an intake passage of the engine, an EGR valve provided in the EGR passage, control means for opening the EGR valve in accordance with enigne operating conditions comprising: first means for detecting flow rate of recirculated

Tamura

1988-01-01

192

Recyclotron III, a recirculating plasma fusion system  

SciTech Connect

This patent describes a recyclotron nuclear fusion system comprising recyclotrons. Each recyclotron comprises cyclotron means for receiving and accelerating charged particles in spiral and work conservative pathways. An output means forms a beam from particles received from the cyclotron means; (i) the cyclotron means comprising (a) a channel shaped electromagnet having a pair of indented polefaces, oriented along an input axis and defining an input axis and defining an input magnetic well, (b) a pair of elongated linear electrodes centered along the input magnetic well arranged generally parallel to the input axis and having a gap therebetween, (c) tuned oscillator means connected to the electrodes for applying an oscillating electric potential thereto, (ii) the output means comprising (e) inverter means comprising an electromagnet having a polarity opposite that of the channel shaped electromagnet oriented contigously therealong for extracting fully accelerated particles from the cyclotron means, and (f) reinverter means comprising an electromagnet having a polarity the same as that of the channel shaped electromagnet for correcting the flightpath of the extracted particles.

Jarnagin, W.S.

1987-01-27

193

CONTRIBUTIONS TO THE KNOWLEDGEMENT OF THE GROWTH TECHNOLOGY OF ONCORHYNCHUS MYKISS SPECIES IN RECIRCULATING AQUACULTURAL SYSTEM CONTRIBU ?II LA CUNOATEREA TEHNOLOGIEI DE CRETERE A SPECIEI ONCORHYNCHUS MYKISS ÎN SISTEM RECIRCULANT  

Microsoft Academic Search

A Recirculating Aquacultural System (RAS) can be de fined as an aquacultural system that incorporates the treatment and reuse of water with less than 10% of the total water volume replaced per day and in which th e environmental conditions are being controlled. The concept of RAS is to reuse a volume of water through continuous treatment. The research was

ANI ALINA RODICA

194

Association of Mycobacteria in Recirculating Aquaculture Systems and Mycobacterial Disease in Fish  

Microsoft Academic Search

Mycobacterium marinum isolates cultivated from tissue containing granulomatous lesions in Florida pompano Trachinotus carolinus and from biofilm samples collected from their tank and water recirculating system had identical (11 of 11 bands) repetitive-sequence-based polymerase chain reaction (rep-PCR) DNA fingerprints. A second M. marinum clone sharing 4 of 11 rep-PCR bands with the first clone was isolated from some fish tissues

Roy P. E. Yanong; Deborah B. Pouder; Joseph O. Falkinham III

2010-01-01

195

A Sodium Bicarbonate Dosing Methodology for pH Management in Freshwater-Recirculating Aquaculture Systems  

Microsoft Academic Search

High-density water-recirculating aquaculture systems with hydraulic retention times above about 5 d must be monitored for alkalinity, and in the vast majority of cases, the alkalinity must be adjusted upwards to assure maintenance of desirable pH levels. Sodium bicarbonate is the preferred additive for increasing alkalinity because it is inexpensive, dissolves rapidly, and is safe for both personnel and fish.

J. Clay Loyless; Ronald F. Malone

1997-01-01

196

Redesigning exhaust-gas recirculation systems in sintering  

Microsoft Academic Search

The recirculation of hot gases (air from the sinter coolers or the cooling zone, sintering waste gases) permits energy conservation and environmental protection in sinter production. A benefit of gas recirculation is the reduced atmospheric emission of harmful materials (CO, CO 2 , H 2 S, SO 2 ) and dust. One common method of hot-gas recirculation is to return

A. A. Vyatkin; S. S. Skachkova; E. G. Dmitrieva; R. N. Shumilov; A. Yu. Morozov

2008-01-01

197

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An internal combustion engine is provided with an exhaust gas recirculating passage for communicating the intake passage and the exhaust passage thereof. The recirculating passage is provided with a valve for controlling the amount of recirculated exhaust gas. A fundamental air-fuel ratio control value for regulating the air-fuel ratio of the intake gas to a predetermined value is corrected by

S. Yoshioka; Y. Nomoto; T. Oda; K. Yokooku

1984-01-01

198

Exhaust gas recirculation system for an internal combustion engine  

SciTech Connect

Disclosed herein is a back pressure control type EGR system for an internal combustion engine, wherein a vacuum modulator has an air introducing chamber which is selectively opened, in accordance with the pressure of recirculated exhaust gas, to a vacuum line connecting an EGR port with a vacuum operated flow control valve. The air introducing chamber is further connected to another vacuum port formed slightly above the EGR port via another vacuum line. Switching valve devices responsive to the temperature of the engine are located on the vacuum lines for stopping the EGR operation when the engine is cold.

Abe, T.; Ota, I.

1980-09-16

199

Microbial diversity of biological filters in recirculating aquaculture systems.  

PubMed

Development of environmentally sustainable farming of marine and freshwater species using recirculating aquaculture systems (RASs) requires a complete understanding of the biological component involved in wastewater treatment. This component integrates biofilters composed of microbial communities whose structure, dynamics, and activities are responsible for system success. Engineering highly efficient, environmentally sound, disease-free, and economically viable systems necessitates a thorough knowledge of microbial processes involved in all facets of RAS biofilters and has only recently been the focus of comprehensive studies. These studies have included the application of molecular tools to characterize community diversity and have identified key processes useful for improving system performance. In this paper we summarize the current understanding of the microbial diversity and physiology of RAS biofilters and discuss directions for future studies. PMID:20371171

Schreier, Harold J; Mirzoyan, Natella; Saito, Keiko

2010-06-01

200

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

PubMed

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 (BOD5, 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO2-N, 90%) and nitrate nitrogen (NO3-N, 68%). Phosphate (PO4-P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO3-N in the culture tank water in RAS were significantly (Psystem (CAS) that simulated static pond culture without wetland treatment. However, no significant difference (Psystems. 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 (Pwater quality and provide a good culture environment, consequently increasing the shrimp growth and survival without water exchange, in a recirculating system. PMID:12663210

Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan

2003-01-01

201

A simple recirculating flow system for the calibration of polar organic chemical integrative samplers (POCIS): effect of flow rate on different water pollutants.  

PubMed

A calibration system for POCIS was developed and used to calculate the sampling rates of eight analytes belonging to pesticides, non-steroidal anti-inflammatory drugs and perfluorinated compounds: atrazine, propazine, terbutylazine, diclofenac, ibuprofen, ketoprofen, perfluorooctanoic acid and perfluorooctanesulfonate. Experiments with a linear velocity of 2.0, 5.1, 10.2 and 15.3 cm/s were carried out for 96 h using two different analyte concentrations. POCIS extracts were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), using multiple reaction monitoring to maximize sensitivity. Results highlighted that the calculated sampling rates are rather constant at the considered concentrations and flow rates. Obtained values of sampling rates were then employed to calculate Time-Weighted Average concentration of the analytes in river and drinking waters. PMID:24468338

Di Carro, Marina; Bono, Luca; Magi, Emanuele

2014-03-01

202

Integrated process control for recirculating cooling water treatment in the coal chemical industry.  

PubMed

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. PMID:21977648

Pei, Y S; Guo, W; Yang, Z F

2011-01-01

203

Cross-flow type internal combustion engine with a small sized exhaust gas recirculating system  

Microsoft Academic Search

A cylinder head of a cross-flow type internal combustion engine is formed with a through hole or a groove which is associated with an exhaust gas recirculating system to simplify the exhaust gas recirculating system and simultaneously to make it small.

Y. Hayashi; H. Kamino; A. Ohnishi; M. Waku

1980-01-01

204

Ozonated seawater induces genotoxicity and hematological alterations in turbot ( Scophthalmus maximus) — Implications for management of recirculation aquaculture systems  

Microsoft Academic Search

Ozonation has proven useful in recirculating aquaculture systems promoting the stabilization of water quality and disease control. Nevertheless, its cytogenetic and physiological effects on fish are still largely unknown. Hence, this research investigated the effects of ozone exposure in juvenile turbot (Scophthalmus maximus) by assessing its genotoxic potential (erythrocytic nuclear abnormalities — ENA — assay) and alterations on hematological parameters

J. Silva; A. Laranjeira; R. Serradeiro; M. A. Santos; M. Pacheco

2011-01-01

205

2-Methylisoborneol and geosmin uptake by organic sludge derived from a recirculating aquaculture system.  

PubMed

In a previous study on a recirculating fish culture system, levels of geosmin and 2-methylisoborneol were found to decrease when culture water was recirculated through the anaerobic sludge digestion treatment stage of the system. This finding led us to the present study in which the geosmin and 2-methylisoborneol removal capacity of the sludge derived from this treatment stage was examined in vitro. It was found that reduction of off-flavor compounds by the sludge was mediated by both chemical/physical sorption and biological degradation. At geosmin and 2-methylisoborneol concentrations within the range of those experienced in fish culture systems, chemical/physical sorption by the sludge was found to account for a 93% reduction in geosmin and a 79% reduction in 2-methylisoborneol from the overlying water within 48h of incubation. Combined with the biological degradation taking place in the sludge, a complete removal of these compounds from the water phase occurred within 9 days of incubation. By means of repeated washing of the geosmin and 2-methylisoborneol contaminate sludge with clean water, relatively small amounts of these compounds were released from the sludge, a possible indication for the fact that absorption, rather than adsorption, underlies the chemical/physical removal process. PMID:18986667

Guttman, Lior; van Rijn, Jaap

2009-02-01

206

Exhaust gas recirculation system in compression-ignition internal combustion engine  

Microsoft Academic Search

In an exhaust gas recirculation system of a compression ignition internal combustion engine, there are provided two passages, that is, an EGR passage for recirculation of exhaust gases and a bypass passage by-passing the throttle valve in the induction passage to allow a supplemental air flow to the engine when EGR is cut off in definite engine operating conditions. These

Shinzawa

1982-01-01

207

Association of Mycobacteria in Recirculating Aquaculture Systems and Mycobacterial Disease in Fish  

E-print Network

Association of Mycobacteria in Recirculating Aquaculture Systems and Mycobacterial Disease in Fish and aquarium surfaces. Therefore, the ecology of the NTM is consistent with reports of infections (e zoonotic potential, a better understanding of mycobacterial ecology and pathogen- esis in recirculating

Watson, Craig A.

208

Engine exhaust gas recirculation system with periodic recalibration of exhaust back pressure reference  

Microsoft Academic Search

The invention discloses an exhaust gas recirculation system in which the flow of recirculated exhaust gas is controlled through an orifice having exhaust back pressure on one side and a control pressure on the other, determined by an EGR valve. Apparatus is provided for sensing the control pressure and controlling the EGR valve in response to the sensed control pressure,

Lahiff

1979-01-01

209

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  

Microsoft Academic Search

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

Krasindh Hangsapreurke; Thon Thamrongnawasawat; Sorawit Powtongsook; Prajuab Lumubol

210

Brackish water desalination by electrodialysis: batch recirculation operation modeling  

Microsoft Academic Search

The shortage of drinking water is a major problem in the South East of Spain. In these areas, it is essential to make use of water from underground reservoirs, most of which are over exploited and suffer from saline contamination given their proximity to the sea.The desalination of brackish water is a means of obtaining low cost drinking water. Electrodialysis

J. M. Ortiz; J. A. Sotoca; E. Expósito; F. Gallud; V. García-García; V. Montiel; A. Aldaz

2005-01-01

211

Association of mycobacteria in recirculating aquaculture systems and mycobacterial disease in fish.  

PubMed

Mycobacterium marinum isolates cultivated from tissue containing granulomatous lesions in Florida pompano Trachinotus carolinus and from biofilm samples collected from their tank and water recirculating system had identical (L1 of 11 bands) repetitive-sequence-based polymerase chain reaction (rep-PCR) DNA fingerprints. A second M. marinum clone sharing 4 of 11 rep-PCR bands with the first clone was isolated from some fish tissues but not from system samples. Water samples yielded low numbers of colonies of mycobacteria (0.08-1.3/mL), but high numbers were recovered from biofilms (260-12,000/swab) and filters (63-21,000/ filter). Mycobacterium hemophilum, M. chelonae, M. trivale, M. gastri, and M. gordonae were isolated from system samples alone. PMID:21413504

Yanong, Roy P E; Pouder, Deborah B; Falkinham, Joseph O

2010-12-01

212

Modeling gas transfer and biological respiration in a recirculating aquaculture system  

Microsoft Academic Search

Recirculating aquaculture system applications of oxygen absorption equipment require consideration of the combined effects of the system's physical, chemical and biological components. Interactions of this type were modeled within a recirculating system incorporating a mixed-flow type rearing vessel, a multi-tube clarifier, a rotating biological contactor (RBC) and a U-tube oxygenator. Finite difference mass transfer calculations, based on reactor theory, were

Luther G. Wood; Barnaby J. Watten; C. Gene Haugh; George S. Libey; Theo A. Dillaha

1996-01-01

213

Performance of the prototype gas recirculation system with built-in RGA for INO RPC system  

Microsoft Academic Search

An open loop gas recovery and recirculation system has been developed for the INO RPC system. The gas mixture coming from RPC exhaust is first desiccated by passing through molecular sieve (3Å+4Å). Subsequent scrubbing over basic active alumina removes toxic and acidic contaminants. The Isobutane and Freon are then separated by diffusion and liquefied by fractional condensation by cooling up

M. Bhuyan; V. M. Datar; A. Joshi; S. D. Kalmani; N. K. Mondal; M. A. Rahman; B. Satyanarayana; P. Verma

214

Diagnosing system for an exhaust gas recirculation system of an automotive engine  

Microsoft Academic Search

A diagnosing system is described for an exhaust gas recirculation system, comprising: means for detecting the position of the EGR valve and for producing a position signal dependent on the position of the EGR valve; and trouble detector means responsive to the valve operating signal and to the position signal for producing a trouble signal as an alarm signal when

1989-01-01

215

Exhaust gas recirculation system for internal combustion engine  

Microsoft Academic Search

An impeller is disposed in an exhaust gas recirculation passage communicating between the exhaust passage and the intake passage of the engine. The impeller supplies part of the exhaust gas positively from the exhaust passage to the intake passage of the engine. The blowing device includes a blower which is driven electrically or mechanically.

Ushimura

1983-01-01

216

Dynamic Scheduling of Internal Exhaust Gas Recirculation Systems.  

E-print Network

manifold to the intake mani- fold through a vacuum actuated valve. The EGR control algorithm is a simple PI events. Optimized valve events can improve the gas exchange process and enable control of internal EGR Exhaust gas recirculation (EGR) was introduced in the early 1970s to reduce the formation of oxides of ni

Stefanopoulou, Anna

217

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?  

Microsoft Academic Search

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 other fish not subjected to stress but sharing the same water of stressed fish.

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

2011-01-01

218

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

PubMed Central

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. PMID:12096047

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

2002-01-01

219

Temporal and Spatial Pore Water Pressure Distribution Surrounding a Vertical Landfill Leachate Recirculation Well  

PubMed Central

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. PMID:21655145

Kadambala, Ravi; Townsend, Timothy G.; Jain, Pradeep; Singh, Karamjit

2011-01-01

220

Temporal and spatial pore water pressure distribution surrounding a vertical landfill leachate recirculation well.  

PubMed

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. PMID:21655145

Kadambala, Ravi; Townsend, Timothy G; Jain, Pradeep; Singh, Karamjit

2011-05-01

221

Systems engineering for ornamental fish production in a recirculating aquaculture system  

Microsoft Academic Search

The aim was to develop a simulation model for determining the optimal layout and management regime for ornamental fish recirculating aquaculture system (ORAS). The work plan involved: (1) quantifying the effects of fish growth rates, the nature of the products, and the management practices; (2) developing a mathematical simulation model of the ORAS, taking into account all factors that directly

Ilan Halachmi

2006-01-01

222

Electron recirculation in electrostatic multicusp systems: II. System performance scaling of one-dimensional rollover wells  

Microsoft Academic Search

In an earlier paper a comprehensive study was made of the recirculation and losses of electrons in their flow through simple inverse power-law potential wells bounded by similarly inverse power-law dependent magnetic fields. This study examined electron flow and loss behavior in the simplest approximation invoked to describe Polywell confinement systems. The importance of this study, and of the present

R. W. Bussard; K. E. King

1992-01-01

223

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

Microsoft Academic Search

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 trout (Oncorhynchus mykiss) were designated to formalin treatments (C0 at 10 and 20mg\\/L formaldehyde) on a daily or weekly basis. Formaldehyde removal rates were

Lars-Flemming Pedersen; Per B. Pedersen; Jeppe L. Nielsen; Per H. Nielsen

2010-01-01

224

Performance of a constructed wetland in treating brackish wastewater from commercial recirculating and super-intensive shrimp growout systems.  

PubMed

A recirculating aquaculture system was developed for treating Pacific white shrimp (Litopenaeus vannamei) production wastewater using an integrated vertical-flow (IVF) and five connected integrated horizontal flow (IHF) constructed wetlands as water treatment filters for mesohaline conditions (8.25‰-8.26‰ salinity). The constructed wetlands demonstrated the ability to reduce total nitrogen, total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total phosphorous, chemical oxygen demand, and total suspended solids to levels significantly lower than those in effluents from culture tanks. Various water quality parameters in the culture tanks were deemed suitable for shrimp culture. The actual ratio of wetland area (A(w)) to culture tank area (A(t)) was 1.1439, and the estimated optimal ratio A(w)/A(t) was approximately 1. The IVF-IHF wetlands showed flexibility and reliability in consistently removing the main pollutants from commercial recirculating and super-intensive shrimp growout systems throughout the culture period. PMID:21852127

Shi, Yonghai; Zhang, Genyu; Liu, Jianzhong; Zhu, Yazhu; Xu, Jiabo

2011-10-01

225

Development and design of a fluidized bed\\/upflow sand filter configuration for use in recirculating aquaculture systems  

Microsoft Academic Search

A fluidized bed\\/upflow sand filter configuration, was developed and designed for utilization in recirculating aquaculture system, specifically the soft-shell crab and soft-shell crawfish industries. These filters were selected and designed because of their ability to withstand clogging and still maintain high levels of water quality for aquaculture production. The effectiveness of sand grain size was used to evaluate fluidized bed

1988-01-01

226

Performance characteristics of fluidised bed biofilters in a novel laboratory-scale recirculation system for rainbow trout: nitrification rates, oxygen consumption and sludge collection  

Microsoft Academic Search

A laboratory-scale recirculating aquaculture system for fluidised bed biofilter evaluation was engineered. The design included all components found in typical full-scale commercial production systems. The system included two identical units each with oxygenation, UV treatment, cooling, biofiltration and a particulates separation device. Water from the two systems was mixed in a degassing unit. A 1 month test period after biofilter

J Skjølstrup; P. H Nielsen; J.-O Frier; E McLean

1998-01-01

227

Application of a gas recirculation system to industrial acetic fermentation processes  

Microsoft Academic Search

This paper describes a gas recirculation system for the exhaust gases from the aerobic fermenters normally used in acetic fermentation processes. With the application of this procedure, it is possible to operate in a closed system, so preventing the large losses of fermentation yield due to evaporation which occur in open systems. In addition, this system reduces losses of volatile

J. M. Gómez; L. E. Romero; L. Caro; D. Cantero

1994-01-01

228

Diagnosing system for an exhaust gas recirculation system of an automotive engine  

SciTech Connect

This patent describes a diagnosing system for an exhaust gas recirculation system having an EGR passage communicating an exhaust pipe of an engine with an intake passage of the engine, an EGR valve provided in the EGR passage, control means for opening the EGR valve in accordance with enigne operating conditions comprising: first means for detecting flow rate of recirculated gas in the EGR passage and for producing an actual EGR rate signal dependent on the flow rate; second means for producing a desired EGR rate signal including an allowable range in accordance with engine operating conditions; and third means responsive to the actual EGR rate signal and the desired EGR rate signal for producing a trouble signal as an alarm signal when the actual EGR rate signal is out of the allowable range.

Tamura, I.

1988-02-09

229

Fish Health Management Considerations in Recirculating Aquaculture Systems -Part 2: Pathogens1  

E-print Network

preventative medicine principles and explains purpose-built recirculat- ing systems for different uses. Part 3 with suppressed immune systems. However, if pathogens become suf- ficiently numerous they can also cause Cir 121 Fish Health Management Considerations in Recirculating Aquaculture Systems - Part 2

Watson, Craig A.

230

Oxygen mass balance in a recirculation aquaculture system for raising European Wels (Silurus glanis L.)  

Microsoft Academic Search

The growth of the European Wels or sheat-fish (Silurus glanis L.) was eva- luated in a recirculation aquaculture system situated in a greenhouse. Recir- culation aquaculture system components were evaluated in terms of oxygen use and generation. Oxygen gradients revealed the main fault of the originally constructed system elements - mechanical and biological filters. The influen- ce of organic matter

Viktoras Mongirdas; Albinas Kusta

2006-01-01

231

Determination of nitrate ion content in recirculating water in petroleum refineries and petrochemical plants  

SciTech Connect

A method for determining nitrate ions, using a 2,6-diacetaminopyridine solution in concentrated sulfuric acid, was investigated. Potassium nitrate solutions with nitrate ion contents of 1 mg/ml, including a 2% aqueous solution of sulfamic acid, a 0.5% solution of antimony trioxide in concentrated sulfuric acid, were used. The solutions were mixed with a 1-4 ml sample of recirculating water in two 25 ml flasks. The optical density of the solution was measured relative to the zero standard of the scale of the calibration curve. Nitrate ion content was measured by the calibration curve, from data obtained in a series of 25-ml volumetric flasks.

Sukhova, N.S.; Bokova, Z.I.

1987-11-01

232

An economic and technical evaluation of integrating hydroponics in a recirculation fish production system  

Microsoft Academic Search

The economic and technical viability of incorporating tomatoes grown hydroponically into a recirculation system for channel catfish production were studied. A unit was planned and budgeted for an annual production of 20 tonnes of fish. A high internal rate of return (IRR) of 27.32% was indicated. Comparative results were derived for a system producing the catfish alone. This showed little

P. A. Chaves; R. M. Sutherland; L. M. Laird

1999-01-01

233

A Multi-Orbit Recirculation System for a Superconducting Linear Accelerator - The Recyclotron  

Microsoft Academic Search

The energy available from a superconducting linear electron accelerator (SCA) may be increased many times by means of an economical multi-orbit recirculation system, which preserves the most desirable characteristics of the SCA: good energy resolution (~10-4), high current and unity duty cycle. Furthermore, these properties of the SCA and its excellent emittance considerably simplify the design of the transport system

R. E. Rand

1973-01-01

234

Exhaust gas recirculation system in compression-ignition internal combustion engine  

SciTech Connect

In an exhaust gas recirculation system of a compression ignition internal combustion engine, there are provided two passages, that is, an EGR passage for recirculation of exhaust gases and a bypass passage by-passing the throttle valve in the induction passage to allow a supplemental air flow to the engine when EGR is cut off in definite engine operating conditions. These two passages are arranged to join together at a junction, in which there is provided a valve to open and close these two passages alternatively so that an adequate egr control is performed in accordance with engine operating conditions with a simplified mechanism.

Shinzawa, M.

1982-02-02

235

Effect of fish size and hydraulic regime on particulate organic matter dynamics in a recirculating aquaculture system: elemental carbon and nitrogen approach  

Microsoft Academic Search

Understanding the capabilities of particulate organic matter removal devices is critical to the development of recirculating aquaculture systems (RAS). The size of fish and water flow rates were evaluated as factors determining the distribution of particulate wastes throughout the RAS. Elemental carbon and nitrogen analyses (CHN) were employed in order to characterize particulate matter and to evaluate the performances of

M. A. Franco-Nava; J. P. Blancheton; G. Deviller; A. Charrier; J. Y. Le-Gall

2004-01-01

236

Intake manifold for internal combustion engine having exhaust gas recirculation system  

Microsoft Academic Search

An intake manifold is described of an internal combustion engine which has an exhaust gas recirculation system. It introduces a part of exhaust gas from an exhaust passage through an EGR gas supply passage into the intake manifold. The intake manifold is provided with an EGR gas outlet opened thereto and connected to the EGR gas supply passage. The EGR

T. Yokoi; E. Takeya; K. Hattori; K. Abe; H. Osawa

1987-01-01

237

Exhaust gas recirculation system with control apparatus for exhaust gas flow control valve  

Microsoft Academic Search

An exhaust gas recirculation system for an internal combustion engine comprises an exhaust gas flow control valve; a vacuum actuator for operation of the flow control valve; and a control apparatus which provides an output vacuum to be applied to the vacuum actuator which is an amplification of the venturi vacuum.

Y. Nakajima; Y. Hayashi; Y. Takagi; K. Sugihara; S. Aoyama

1977-01-01

238

Exhaust gas recirculation system with control apparatus for exhaust gas flow control valve  

Microsoft Academic Search

An exhaust gas recirculation system comprises an exhaust gas flow control valve; a vacuum actuator for operation of the flow control valve; and a control apparatus for the vacuum actuator. The control apparatus comprises a vacuum regulator and a vacuum motor for actuating the vacuum regulator in response not only to the venturi vacuum but also to the intake manifold

K. Sugihara; Y. Nakajima; Y. Hayashi

1977-01-01

239

Exhaust gas recirculation system with control apparatus for exhaust gas flow control valve  

Microsoft Academic Search

An exhaust gas recirculation system comprises an exhaust gas flow control valve; a vacuum actuator for operation of the flow control valve; and a control apparatus constructed and arranged such that an output vacuum of the control apparatus applied to the vacuum actuator is an amplification of the venturi vacuum modified by the intake manifold vacuum.

Y. Hayashi; Y. Nakajima; K. Sugihara; S. Nagumo

1977-01-01

240

Intake manifold for internal combustion engine having exhaust gas recirculation system  

Microsoft Academic Search

An intake manifold is described for an internal combustion engine equipped with an exhaust gas recirculation system for introducing a part of the exhaust from an exhaust gas passage through an EGR pipe into an intake manifold. The intake manifold is provided with an EGR gas outlet port opened thereto and connected to the EGR pipe, and is also provided

Y. Noguchi; T. Yokoi; E. Takeya; H. Osawa

1987-01-01

241

Removal efficiency and balance of nitrogen in a recirculating aquaculture system integrated with constructed wetlands  

Microsoft Academic Search

The nitrogen (N) balance for aquaculture is an important aspect, especially in China, and it is attributed to the eutrophication in many freshwater bodies. In recent years, constructed wetlands (CWs) have been widely used in wastewater treatment and ecosystem restoration. A recirculating aquaculture system (RAS) consisting of CWs and 4 fish ponds was set up in Wuhan, China. Channel catfish

Fei Zhong; Wei Liang; Tao Yu; Shui P. Cheng; Feng He; Zhen B. Wu

2011-01-01

242

Response of Bacterial Biofilms in Recirculating Aquaculture Systems to Various Sanitizers  

Microsoft Academic Search

Pathogenic microorganisms may be incorporated into biofilms found in aquaculture systems, causing recurring exposure to potential disease agents. Aerobic plate counts, the presence of Enterobacteriaceae, and the presence of Escherichia coli, modified to express a green fluorescent protein (GFP E. coli), was used to evaluate the effectiveness of various sanitizers in decreasing bacterial incorporation into newly generated biofilms in recirculating

Robin K. King; George J. Flick Jr; Stephen A. Smith; Merle D. Pierson; Gregory D. Boardman; Charles W. Coale Jr

2008-01-01

243

Evaluation of nitrifying bacteria product to improve nitrification efficacy in recirculating aquaculture systems  

Microsoft Academic Search

Recirculating aquaculture systems (RASs) rely on nitrification to convert toxic ammonia and nitrite to less toxic nitrate. Nitrification is accomplished using biofilters with nitrifying bacteria and can be inefficient in biofilters that are new or that have been compromised due to stressors. Failure in a biofilter can result in very high levels of ammonia or nitrite, both of which are

David D. Kuhn; David D. Drahos; Lori Marsh; George J. Flick Jr.

2010-01-01

244

Quantification of anammox activity in a denitrification reactor for a recirculating aquaculture system  

Microsoft Academic Search

The activity of anammox bacteria in a denitrification reactor in a recirculating aquaculture system (RAS) for gilthead seabream production was investigated. Organic matter, extracted from the pond's solid filter, was used as the electron donor and carbon source for the denitrification reaction. The reactor was operated at four solid retention times (SRT). At steady state, anammox activity showed similar activity

Ori Lahav; Iris Bar Massada; Dimitry Yackoubov; Ruth Zelikson; Noam Mozes; Yossi Tal; Sheldon Tarre

2009-01-01

245

Growth of juvenile cobia, Rachycentron canadum, at three different densities in a recirculating aquaculture system  

Microsoft Academic Search

Cobia (Rachycentron canadum) is an excellent aquaculture candidate and culture of this species continues to develop worldwide. Current culture practices generally include larviculture and production of early juveniles on land with final growout occurring in ocean cages. Data indicate that production and\\/or growout of juveniles in land based recirculating systems may be hampered by growth depression in fish held at

Kenneth A. Webb; Glenn M. Hitzfelder; Cynthia K. Faulk; G. Joan Holt

2007-01-01

246

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

Microsoft Academic Search

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. Bacteria were produced in growth reactors under different conditions: 7¿h hydraulic retention time (HRT) vs. 2¿h, sodium

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

2007-01-01

247

Comparison of Bacterial Presence in Biofilms on Different Materials Commonly Found in Recirculating Aquaculture Systems  

Microsoft Academic Search

Recirculating aquaculture offers an economic potential for successful fish farming requiring limited resources. However, this form of aquaculture may present a potential unacceptable health risk for the fish. Pathogenic microorganisms may be incorporated into biofilms found in aquaculture systems, causing recurring exposure to disease agents. The presence of E. colimodified to express a green fluorescent protein (GFP E. coli) was

Robin K. King; George J. Flick; Stephen A. Smith; Merle D. Pierson; Gregory D. Boardman; Charles W. Coale

2006-01-01

248

Part-day ozonation for nitrogen and organic carbon control in recirculating aquaculture systems  

Microsoft Academic Search

Recent work on ozone application in recirculating aquaculture systems (RAS) gives guidelines as to the daily ozone dose as a function of feed rates, but does not indicate whether the ozone should be added continuously throughout the day or in shorter, more intense doses. This study examined the effect of adding the same total amount of ozone (15 g ozone

Valdis Krumins; James Ebeling; Fred Wheaton

2001-01-01

249

Biodegradable polymers as solid substrate and biofilm carrier for denitrification in recirculated aquaculture systems  

Microsoft Academic Search

A simple process for nitrate removal is proposed for its application in aquaculture. Biodegradable polymer pellets are acting as solid substrate and biofilm carrier for denitrification. Laboratory experiments with conventional aquaria and fish were used to examine the feasibility and a first evaluation of the process performance in a recirculated aquaculture system. All over the test-period the fish were in

A. Boley; W.-R. Müller; G. Haider

2000-01-01

250

Valve device for an exhaust gas recirculation system of an internal combustion engine  

Microsoft Academic Search

A valve device for an exhaust gas recirculation system of an internal combustion engine to disclosed. This device has a diaphragm mechanism having a diaphragm to form at least one chamber which is connected to an engine port and has a valve member connected to said diaphragm via a rod to open the valve member against a force caused by

M. Ando; K. Katow; M. Yamazaki

1978-01-01

251

Experimental Bleaching of a Reef-Building Coral Using a Simplified Recirculating Laboratory Exposure System  

EPA Science Inventory

Determining stressor-response relationships in reef building corals is a critical need for researchers because of global declines in coral reef ecosystems. A simplified recirculating coral exposure system for laboratory testing of a diversity of species and morphologies of reef b...

252

On thermoelectric power conversion from heat re-circulating combustion systems F. J. Weinberg  

E-print Network

On thermoelectric power conversion from heat re-circulating combustion systems F. J. Weinberg Fax: 4420 7594 5604 Word count: 3750 Diags. equivalent: 1600 5350 #12;On thermoelectric power the absolute maximum efficiency of energy conversion by thermoelectric devices that operate as part of the heat

253

Quantitative role of shrimp fecal bacteria in organic matter fluxes in a recirculating shrimp aquaculture system.  

PubMed

Microorganisms play integral roles in the cycling of carbon (C) and nitrogen (N) in recirculating aquaculture systems (RAS) for fish and shellfish production. We quantified the pathways of shrimp fecal bacterial activities and their role in C- and N-flux partitioning relevant to culturing Pacific white shrimp, Penaeus (Litopenaeus) vannamei, in RAS. Freshly produced feces from P. vannamei contained 0.6-7 × 10(10) bacteria g(-1) dry wt belonging to Bacteroidetes (7%), Alphaproteobacteria (4%), and, within the Gammaproteobacteria, almost exclusively to the genus Vibrio (61%). Because of partial disintegration of the feces (up to 27% within 12 h), the experimental seawater became inoculated with fecal bacteria. Bacteria grew rapidly in the feces and in the seawater, and exhibited high levels of aminopeptidase, chitinase, chitobiase, alkaline phosphatase, ?- and ?-glucosidase, and lipase activities. Moreover, fecal bacteria enriched the protein content of the feces within 12 h, potentially enriching the feces for the coprophagous shrimp. The bacterial turnover time was much faster in feces (1-10 h) than in mature RAS water (350 h). Thus, shrimp fecal bacteria not only inoculate RAS water but also contribute to bacterial abundance and productivity, and regulate system processes important for shrimp health. PMID:21426366

Beardsley, Christine; Moss, Shaun; Malfatti, Francesca; Azam, Farooq

2011-07-01

254

Field evaluation of a horizontal well recirculation system for groundwater treatment: Pilot test at the Clean Test Site Portsmouth Gaseous Diffusion Plant, Piketon, Ohio  

SciTech Connect

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.

Muck, M.T.; Kearl, P.M.; Siegrist, R.L. [and others] [and others

1998-08-01

255

Water cooling tower and water level control system therefor  

Microsoft Academic Search

This patent describes an improved water cooling tower system including a water cooling tower structure having a top portion, a bottom portion, an intermediate portion therebetween, a water-collecting basin operatively disposed in the bottom portion of the structure, a heat exchange means operatively disposed in the intermediate portion of the structure, means for recirculating the water from the water-collecting basin

Kinkead

1989-01-01

256

[Performance of recirculating aquaculture systems in the intensive farming of Pacú Piaractus mesopotamicus (Characiformes: Characidae)].  

PubMed

An alternative to intensify fish production, reducing the environmental impact and production costs are recirculating aquaculture systems (RAS). The performance of a RAS was evaluated, as fish growth and water quality conditions, in a culture of Piaractus mesopotamicus reared for ornamental purposes. Two commercial food brands with different protein contents (18%-T1 and 28%-T2), were given to juvenile fishes during an eight weeks period. Growth was measured bi-weekly: standard length (Lp), peak height (A), weight and multiple condition factor (KM). The evaluation of water parameters included: dissolved oxygen, NH3-NH4, pH, NO2, NO3, KH carbonate hardness and PO4. NH3-N rate production was analyzed following Timmons-Ebeling model. Results demonstrated significant differences in weight only, and T2 showed a 7.5% higher value than T1; nevertheless, treatment T1 had a higher KM. In general, water quality values were suitable for growth: OD=T1: 4.23 +/- 1.23; T2: 4.13 +/- 0.86; NH3=T1: 0.02 +/- 0.02; T2: 0.06 +/- 0.10; however, pH was an exception (T1: 6.95 +/- 0.98; T2: 7.11 +/- 1.03), displaying lethal rates (<5) by the fifth week. Systems NH3 removal had a 99.4% to 100% efficiency. Final fish biomass was 22.03kg for T1 and 27.49kg for T2. We concluded that the systems were able to maintain suggested density up to the experimental fifth week. Water quality parameters remained in suitable levels, with the pH exception. Cultured fishes reached their commercial size (10cm) in eight weeks. PMID:22458232

Domínguez Castanedo, Omar; Martínez Espinosa, David Alberto

2012-03-01

257

A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system.  

PubMed

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. PMID:19819130

Endut, Azizah; Jusoh, A; Ali, N; Wan Nik, W B; Hassan, A

2010-03-01

258

Removal of ammonium-N from a recirculation aquacultural system using an immobilized nitrifier  

Microsoft Academic Search

Various immobilization methods were evaluated for the removal of ammonium-N from recirculating aquacultural water. Ba-alginate, Ca-alginate, carrageenan, and agar beads were prepared with nitrifer consortium from the activated sludge of a sewage treatment facility in Sooyoung, Pusan, South Korea. Batch bioreactor tests for the determination of the effectiveness of the immobilized nitrifier and the optimum hydraulic retention time (HRT) were

Sung-Koo Kim; Insoo Kong; Byung-Hun Lee; Limseok Kang; Min-Gyu Lee; Kuen Hack Suh

2000-01-01

259

Performance and operation of a rotating biological contactor in a tilapia recirculating aquaculture system  

Microsoft Academic Search

This paper describes the performance characteristics of an industrial-scale air-driven rotating biological contactor (RBC) installed in a recirculating aquaculture system (RAS) rearing tilapia at 28°C. This three-staged RBC system was configured with stages 1 and 2 possessing approximately the same total surface area and stage 3 having approximately 25% smaller. The total surface area provided by the RBC equaled 13,380m2.

Brian L. Brazil

2006-01-01

260

Membrane filtration coupled with chemical precipitation to treat recirculating aquaculture system effluents.  

PubMed

Effluents from recirculating aquaculture systems (RAS) contain high concentrations of nitrogen and phosphorous wastes and thus often require proper treatment to prevent potential detrimental impacts on receiving water bodies. The purpose of this study was to evaluate the feasibility of membrane filtration coupled with chemical precipitation as a pretreatment step with emphasis on phosphorus removal from RAS effluents. Chemical precipitation tests were conducted by adding magnesium chloride and alum at different chemical concentrations and pH values, respectively. Crossflow, flat-sheet membrane filtration modules were used to examine the effects of transmembrane pressure and crossflow velocity in terms of solid/liquid separation efficiency and permeate flux decline. The results showed that membrane filtration can effectively separate the phosphorus precipitates after chemical precipitation. The total phosphorus in the treated effluent was reduced to less than 0.05 mg L(-1) with a removal efficiency of more than 90%. However, much lower removal efficiencies were obtained for total organic carbon (TOC), total nitrogen, and turbidity. It was concluded that membrane filtration coupled with chemical precipitation can become an effective, compact treatment technology to meet the stringent regulatory requirements for RAS effluent discharge. PMID:17071913

Yang, Ling; Zhou, Hongde; Moccia, Richard

2006-01-01

261

The effect of temperature and pH on the growth and physiological response of juvenile yellowtail kingfish Seriola lalandi in recirculating aquaculture systems  

Microsoft Academic Search

A search for a viable new fish species for culture in recirculating aquaculture systems (RAS) in the Netherlands identified yellowtail kingfish Seriola lalandi as having excellent potential. To assist in determining the most appropriate water quality conditions for this species in RAS, the effect of water temperature (21, 23.5, 25, 26.5 and 29 °C) and pH (6.58, 7.16 and 7.85)

W. Abbink; A. Blanco; J. A. C. Roques; G. Partridge; K. Kloet; O. Schneider

2012-01-01

262

Combining systems for leachate recirculation and landfill gas collection  

Microsoft Academic Search

To move landfill bioreactor treatment systems from the experimental level to viable landfill operations across the country, alternative methods must be designed, operated and proven at full-scale landfills. The system installed at the Alachua County Southwest Landfill in Florida was originally designed for leachate injection alone, but was successfully converted to a combined system for gas and leachate management after

T. G. Townsend; W. L. Miller; R. A. Bishop; J. H. Carter

2009-01-01

263

Integrated exhaust gas recirculation and charge cooling system  

DOEpatents

An intake system for an internal combustion engine comprises an exhaust driven turbocharger configured to deliver compressed intake charge, comprising exhaust gas from the exhaust system and ambient air, through an intake charge conduit and to cylinders of the internal combustion engine. An intake charge cooler is in fluid communication with the intake charge conduit. A cooling system, independent of the cooling system for the internal combustion engine, is in fluid communication with the intake charge cooler through a cooling system conduit. A coolant pump delivers a low temperature cooling medium from the cooling system to and through the intake charge cooler for the transfer of heat from the compressed intake charge thereto. A low temperature cooler receives the heated cooling medium through the cooling system conduit for the transfer or heat therefrom.

Wu, Ko-Jen

2013-12-10

264

Characterizing the structural diversity of a bacterial community associated with filter materials in recirculating aquaculture systems of Scortum barcoo.  

PubMed

The bacterial community structure associated with filter materials in the recirculating aquaculture system of Scortum barcoo was investigated using the 16S rRNA gene clone library method. Preliminary results showed that the clone library constructed from the initial operation condition was characterized by 31 taxa of bacteria belonging to eight phyla including Proteobacteria, Acidobacteria, Firmicutes, Fusobacteria, Sphingobacteria, Bacteroidetes, Verrucomicrobiae, and Actinobacteria. There were 14 taxa of bacteria belonging to four phyla including Proteobacteria, Acidobacteria, Planctomycetacia, and Nitrospirae from the stable operation condition where the water quality was well maintained. Nitrospirae was only found under the stable operation condition in this study. Our results further indicated that Nitrospira was dominated by members of the Nitrospira sp. lineages, with a minor fraction related to Nitrospira moscoviensis and an unknown Nitrospira cluster. These great differences of both diversity and composition between two operation conditions suggested that the composition of the microbial community varied with the degree of water quality in the recirculating aquaculture system of S. barcoo. PMID:22339297

Zhu, Peng; Ye, Yangfang; Pei, Fangfang; Lu, Kaihong

2012-03-01

265

A closed-cycle gas recirculating system for rare-gas halide excimer lasers  

Microsoft Academic Search

A closed-cycle recirculating system is described which enables prolonged operation of a rare-gas halide excimer laser on a single charge of rare-gas mixture. The flowing gas is continuously purified in a high-temperature titanium gettering furnace, following removal of the halogen by reaction to form a volatile, but condensable, metal halide. The halogen is reintroduced after the rare-gas purification, being consumed

P. M. Johnson; N. Keller; R. E. Turner

1978-01-01

266

Evaluation of full-scale carbon dioxide stripping columns in a coldwater recirculating system  

Microsoft Academic Search

The objective of this research was to evaluate the dissolved carbon dioxide stripping efficiency of two types of 1-m tall structured plastic packing (tubular NORPAC and structured block CF-3000 Accu-Pac media) that were placed separately in two full-scale forced-ventilation cascade columns that were located within a coldwater recirculating aquaculture system at the Freshwater Institute. These two structured packing types were

Steven T. Summerfelt; John Davidson; Thomas Waldrop

2003-01-01

267

Can dissolved aquatic humic substances reduce the toxicity of ammonia and nitrite in recirculating aquaculture systems?  

Microsoft Academic Search

In recirculating rearing systems of aquatic food organisms, humic substances (HSs) accumulate along with toxic nitrogen species (nitrite, unionized ammonia). The aim of the present study was to find out whether or not HSs have the capability to modify the acute toxicity of nitrite and unionized ammonia; and whether different HS qualities cause similar effects in fish. 144-h-Embryo-Larval-Test (ELT) was

Thomas Meinelt; Hana Kroupova; Angelika Stüber; Bernhard Rennert; Andreas Wienke; Christian E. W. Steinberg

2010-01-01

268

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

USGS Publications Warehouse

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 ?g/g) in the RAS and were greatest at 6 h posttreatment (11.09 ?g/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 ?g/L) and 11 h (442 ?g/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.

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

2014-01-01

269

Solar hot water heating system  

SciTech Connect

A solar hot water heating system is provided with solar collectors connected to a hot water storage tank with a recirculating pump to circulate the cooler water in the storage tank through the collector to absorb heat therefrom and to be returned to the storage tank. A plurality of temperature sensors are placed throughout the system to monitor various temperatures and to develop control signals for energizing or de-energizing the recirculating pump, for opening and closing solenoid valves to isolate the solar collectors from the storage tank and for opening and closing solenoid valves to permit supply water to circulate at a predetermined rate through the solar collectors. The storage tank is provided with inlet and outlet stratifier tubes which, while permitting water to be fed into and withdrawn from the tank, produces stratification of the water stored within the tank and increases the overall efficiency of the system.

Budzynski, J. V.; James, D. A.

1981-02-03

270

EXHAUST GAS RECIRCULATION  

E-print Network

EXHAUST GAS RECIRCULATION (EGR) COOLER TESTING Southwest Research Institute® #12;overnment) and oxides of nitrogen (NOx). The use of exhaust gas recirculation (EGR) coolers is considered research, offers complete facilities for testing diesel engines and their emissions control systems

Chapman, Clark R.

271

Aerobic and Anoxic Growth and Nitrate Removal Capacity of a Marine Denitrifying Bacterium Isolated from a Recirculation Aquaculture System  

Microsoft Academic Search

Bacterial biofilters used in marine recirculation aquaculture systems need improvements to enhance nitrogen removal efficiency.\\u000a Relatively little is known about biofilter autochthonous population structure and function. The present study was aimed at\\u000a isolating and characterizing an autochthonous denitrifying bacterium from a marine biofilter installed at a recirculation\\u000a aquaculture system. Colonization of four different media in a marine fish farm was

Maria-Teresa Borges; André Sousa; Paolo De Marco; Ana Matos; Petra Hönigová; Paula M. L. Castro

2008-01-01

272

Exhaust gas recirculation system for crankcase scavenged two cycle engine  

Microsoft Academic Search

This patent describes a two cycle crankcase scavenged engine comprising: a cylinder having a piston reciprocable disposed, the piston and cylinder forming a combustion chamber; a crankcase; an exhaust port opening into the combustion chamber; exhaust system means connected to the exhaust port for conducting exhaust gas away from the engine and cooling the exhaust gas; means for forming an

V. R. Kaufman; M. S. Geringer

1987-01-01

273

Biomass management in recirculating aquaculture systems using queuing networks  

Microsoft Academic Search

Queuing network contains a series of service facilities (in our case, culture tanks or ponds), at some or all of which, a customer (fish) must receive service; it is, therefore, necessary to study the entire network. A culture tank or pond can be seen as a queuing system in which neither a queue (“over-holding” of fish in tank A before

Ilan Halachmi

2007-01-01

274

Exhaust gas recirculation system in an internal combustion engine  

Microsoft Academic Search

A back pressure-controlled EGR system in an internal combustion engine is described that is comprised of an EGR valve with a pressure control chamber disposed in an EGR conduit connecting an exhaust pipe to an intake pipe of the engine, and a back pressure transducer having a sub-atmospheric pressure chamber connected to said EGR valve means and having a pressure

H. Nohira; M. Tanaka

1978-01-01

275

Improvement of Waste Decomposition in Leachate Recirculation Simulated Landfill by High Water Addition  

Microsoft Academic Search

A considerable amount of research has been conducted to demonstrate the development of bioreactor landfills promoted by leachate recirculation (1-10). The effectiveness of leachate recirculation has been well documented in lysimeter studies (1, 5, 11, 12), test cell studies (2, 13, 14-16) and full-scale studies (17-20). However, the results from these investigations might not be applied appropriately to Thailand

N. Sanphoti; S. Towprayoon; P. Chaiprasert; A. Nopharatana

276

The growth of disk abalone, Haliotis discus hannai at different culture densities in a pilot-scale recirculating aquaculture system with a baffled culture tank  

Microsoft Academic Search

The growth rate of disk abalone, Haliotis discus hannai, energy consumption and changes in water quality were monitored in a pilot-scale recirculating aquaculture system (RAS) for 155 days. Baffles were installed in the RAS culture tanks to enlarge the attachment area and clean out solid waste materials automatically by hydraulic force only. The experimental disk abalones, of shell length 24.5±0.5mm,

Hyung-Bae Kim; Pyong-Kih Kim; Jae-Yoon Jo

2008-01-01

277

Production Characteristics and Body Composition of Florida Pompano Reared to Market Size at Two Different Densities in Low-Salinity Recirculating Aquaculture Systems  

Microsoft Academic Search

The effect of culture density on production characteristics and body composition of Florida pompano Trachinotus carolinus reared to market size using recirculating aquaculture systems (RASs) maintained at a salinity of 5‰ was evaluated in a 110-d growth trial (water temperature = 27.0–28.5°C). Juvenile Florida pompano (mean weight ± SE = 259.0 ± 3.0 g) were stocked into two tanks from

Charles R. Weirich; Paul S. Wills; Richard M. Baptiste; Peter N. Woodward; Marty A. Riche

2009-01-01

278

Un formalisme de systemes a sauts pour la recirculation optimale des casses dans une machine a papier  

Microsoft Academic Search

Increasing closure of white water circuits is making mill productivity and quality of paper produced increasingly affected by the occurrence of paper breaks. In this thesis the main objective is the development of white water and broke recirculation policies. The thesis consists of three main parts, respectively corresponding to the synthesis of a statistical model of paper breaks in a

Maryam Khanbaghi

1998-01-01

279

Florfenicol Residues in Rainbow Trout after Oral Dosing in Recirculating and Flow-through Culture Systems.  

PubMed

Abstract 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 ?g/g) in the RAS and were greatest at 6 h posttreatment (11.09 ?g/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 ?g/L) and 11 h (442 ?g/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. Received January 8, 2014; accepted July 7, 2014. PMID:25321636

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

2014-12-01

280

The ultra-high lime with aluminum process for removing chloride from recirculating cooling water  

E-print Network

Chloride is a deleterious ionic species in cooling water systems because it is important in promoting corrosion. Chloride can be removed from cooling water by precipitation as calcium chloroaluminate using ultra-high lime with aluminum process (UHLA...

Abdel-wahab, Ahmed Ibraheem Ali

2004-09-30

281

Electron recirculation in electrostatic multicusp systems: II. System performance scaling of one-dimensional rollover wells  

SciTech Connect

In an earlier paper a comprehensive study was made of the recirculation and losses of electrons in their flow through simple inverse power-law potential wells bounded by similarly inverse power-law dependent magnetic fields. This study examined electron flow and loss behavior in the simplest approximation invoked to describe Polywell confinement systems. The importance of this study, and of the present paper, is that the power balance in Polywell systems is determined entirely by the rate of electron losses; if these are large, then the system can not yield net power. Thus it is of interest to determine those conditions that results in small losses, and to design experiments and systems to attempt to achieve and operate at these most favorable conditions, in order to test and prove the efficacy of the system for the generation of net power from fusion reactions. The outline and summary of this problem presented is generally repeated here, with some modifications to clarify particular physics issues of most concern, in order to avoid having to refer to the earlier document for this general description. As noted, a large body of work has been undertaken over the past 35 or so years in the study of general cusp confinement of plasmas. Nearly all of this has examined single particle electron (or ion) motion or the motion of particles in neutral plasmas within cusped magnetic systems, generally without internal electric potential fields.**INVALID KEYWORDS: controlled nuclear fusion, electron flux, plasma devices, confinement, performance, engineering, scaling factor, multicusp systems, polywell systems

Bussard, R.W.; King, K.E.

1992-01-01

282

Diagnosing system for an exhaust gas recirculation system of an automotive engine  

SciTech Connect

A diagnosing system is described for an exhaust gas recirculation system, comprising: means for detecting the position of the EGR valve and for producing a position signal dependent on the position of the EGR valve; and trouble detector means responsive to the valve operating signal and to the position signal for producing a trouble signal as an alarm signal when the detecting means produces a position signal of an actual closed state of the EGR value and the control means produces a valve operating signal representing an open state of the EGR valve. The detecting means is a photoelectric transducer, the photoelectric transducer comprises a photodiode and a phototransistor, and the transducer includes a shaft connected to a valve body of the EGR valve. The shaft is movable by movement of the valve body into a path between the photodiode and phototransistor, and the transducer includes a U-shaped holder having the photodiode and phototransistor facing each other on arms of the holder.

Ichikawa, K.

1989-04-25

283

Characterization of the effluent from an intensive marine recirculating system for the culture of fin fish, and studies on effluent based culture of microalgae.  

E-print Network

??Intensive recirculating aquaculture systems (RAS) routinely discharge effluent that, while relatively small in volume, is particularly enriched in nutrients. The objectives of this study were… (more)

Truesdale, Stephen G.

2009-01-01

284

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

285

Multi-objective optimization of water-using systems  

Microsoft Academic Search

Industrial water systems often allow efficient water uses via water reuse and\\/or recirculation. The design of the network layout connecting water-using processes is a complex problem which involves several criteria to optimize. Most of the time, this design is achieved using Water Pinch technology, optimizing the freshwater flow rate entering the system. This paper describes an approach that considers two

Carlos E. Mariano-Romero; Victor H. Alcocer-Yamanaka; Eduardo F. Morales

2007-01-01

286

A laboratory-scale recirculating aquaculture system for juveniles of freshwater pearl mussel Hyriopsis ( Limnoscapha) myersiana (Lea, 1856)  

Microsoft Academic Search

Growth and survival rates of juvenile freshwater pearl mussels Hyriopsis (Limnoscapha) myersiana (Lea, 1856) were compared at 0–120 days when reared in two closed recirculating aquacultural systems. System I was composed of a glass aquarium with a filter cabinet (combination of pebbles, ground freshwater mussel shells and nylon fiber), a UV tube, a resting cabinet, and a plastic culture unit. The

Satit Kovitvadhi; Uthaiwan Kovitvadhi; Pichan Sawangwong; Jorge Machado

2008-01-01

287

Advances in rearing cobia Rachycentron canadum larvae in recirculating aquaculture systems: Live prey enrichment and greenwater culture  

Microsoft Academic Search

Cobia Rachycentron canadum is a relatively hardy species which exhibits high rates of growth during the larval and juvenile periods. Currently, this species is considered to be a good candidate for commercial production in recirculating aquaculture systems. However, little information is available regarding the nutritional requirements of cobia larvae in such systems, and this information is required to advance commercial

Cynthia K. Faulk; G. Joan Holt

2005-01-01

288

A Mathematical Model of Solute Coupled Water Transport in Toad Intestine Incorporating Recirculation of the Actively Transported Solute  

PubMed Central

A mathematical model of an absorbing leaky epithelium is developed for analysis of solute coupled water transport. The non-charged driving solute diffuses into cells and is pumped from cells into the lateral intercellular space (lis). All membranes contain water channels with the solute passing those of tight junction and interspace basement membrane by convection-diffusion. With solute permeability of paracellular pathway large relative to paracellular water flow, the paracellular flux ratio of the solute (influx/outflux) is small (2–4) in agreement with experiments. The virtual solute concentration of fluid emerging from lis is then significantly larger than the concentration in lis. Thus, in absence of external driving forces the model generates isotonic transport provided a component of the solute flux emerging downstream lis is taken up by cells through the serosal membrane and pumped back into lis, i.e., the solute would have to be recirculated. With input variables from toad intestine (Nedergaard, S., E.H. Larsen, and H.H. Ussing, J. Membr. Biol. 168:241–251), computations predict that 60–80% of the pumped flux stems from serosal bath in agreement with the experimental estimate of the recirculation flux. Robust solutions are obtained with realistic concentrations and pressures of lis, and with the following features. Rate of fluid absorption is governed by the solute permeability of mucosal membrane. Maximum fluid flow is governed by density of pumps on lis-membranes. Energetic efficiency increases with hydraulic conductance of the pathway carrying water from mucosal solution into lis. Uphill water transport is accomplished, but with high hydraulic conductance of cell membranes strength of transport is obscured by water flow through cells. Anomalous solvent drag occurs when back flux of water through cells exceeds inward water flux between cells. Molecules moving along the paracellular pathway are driven by a translateral flow of water, i.e., the model generates pseudo-solvent drag. The associated flux-ratio equation is derived. PMID:10919860

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

2000-01-01

289

Dynamic Control of Engine NOx Emissions: Characterization and Improvement of the Transient Response of an Exhaust Gas Recirculation System  

Microsoft Academic Search

An effective method for reducing NOx emissions from automotive engines is to use exhaust gas recirculation (EGR) to dilute the inducted air-fuel charge. Previous work has shown that degraded propagation delay and rise time characteristics of an EGR system can result in increases in NOx emissions for engine operation over dynamic rpm\\/torque versus time trajectories as exemplified by the Federal

M. J. Throop; D. R. Hamburg

1985-01-01

290

The Heat Transfer and the Soot Deposition Characteristics in Diesel Engine Exhaust Gas Recirculation System Cooling Devices  

Microsoft Academic Search

Exhaust gas recirculation (EGR) cooiing devices are used in EGR systems to significantly reduce NOx emissions from diesel engines. However, the thermal and hydraulic performances of these devices change over time during operation due to the deposition of soot from the diesel exhaust gas in these devices. The objective of this work was to investigate in detail the heat transfer

Basel Ismail A. Ismail

2004-01-01

291

The heat transfer and the soot deposition characteristics in diesel engine exhaust gas recirculation system cooling devices  

Microsoft Academic Search

Exhaust gas recirculation (EGR) cooling devices are used in EGR systems to significantly reduce NOx emissions from diesel engines. However, the thermal and hydraulic performances of these devices change over time during operation due to the deposition of soot from the diesel exhaust gas in these devices. The objective of this work was to investigate in detail the heat transfer

Basel Ismail A Ismail

2004-01-01

292

Evaluating the effects of organic carbon on biological filtration performance in a large scale recirculating aquaculture system  

Microsoft Academic Search

Studies evaluating the impact of organic carbon on biological filters at the large scale for aquaculture production are lacking. Understanding the performance characteristics of different biofilters under actual production conditions will be the only means by which recirculating system designers may properly select and size biological filters for commercial production use. Previous studies have determined the impact of organic carbon

Todd C. Guerdat; Thomas M. Losordo; John J. Classen; Jason A. Osborne; Dennis DeLong

2011-01-01

293

Characterization of rainbow trout ( Oncorhynchus mykiss) intestinal microbiota and inflammatory marker gene expression in a recirculating aquaculture system  

Microsoft Academic Search

Intestinal microbiota and host inflammatory marker gene expression were characterized in rainbow trout (Oncorhynchus mykiss) during a feeding trial designed to determine the digestibility of soybean meal and fish meal. The trial was conducted in a freshwater, biofiltered recirculating aquaculture system in Saskatoon, Canada. Intestinal contents and tissue were collected from nine fish on each of the two experimental diets

Graeme S. Mansfield; Atul R. Desai; Stephanie A. Nilson; Andrew G. Van Kessel; Murray D. Drew; Janet E. Hill

2010-01-01

294

Particulate matter dynamics and transformations in a recirculating aquaculture system: application of stable isotope tracers in seabass rearing  

Microsoft Academic Search

The control of adverse effects and the possibility of removing suspended solids from recirculating aquaculture systems (RAS) are the principal challenges facing aquaculture engineers. However, their dynamics and transformations are not yet well known. In this study, carbon and nitrogen stable isotopes values (?13C and ?15N) were used as tracers of particulate matter in a seabass RAS. An isotopic mixing

Miguel-Angel Franco-Nava; Jean-Paul Blancheton; Geneviève Deviller; Jean-Yves Le-Gall

2004-01-01

295

Establishment of a real-time PCR method for quantification of geosmin-producing Streptomyces spp. in recirculating aquaculture systems  

Microsoft Academic Search

Geosmin and 2-methylisoborneol (MIB) have been associated with off-flavour problems in fish and seafood products, generating a strong negative impact for aquaculture industries. Although most of the producers of geosmin and MIB have been identified as Streptomyces species or cyanobacteria, Streptomyces spp. are thought to be responsible for the synthesis of these compounds in indoor recirculating aquaculture systems (RAS). The

Marc Auffret; Alexandre Pilote; Émilie Proulx; Daniel Proulx; Grant Vandenberg; Richard Villemur

296

Method of assembling a valve device for an exhaust gas recirculation system of an internal combustion engine  

Microsoft Academic Search

A valve device for an exhaust gas recirculation system of an internal combustion engine is described, which has a diaphragm mechanism having a diaphragm to form at least one chamber which is connected to an engine port and has a valve member connected to said diaphragm via a rod to open the valve member against a force caused by a

M. Ando; K. Katow; M. Yamazaki

1979-01-01

297

Investigations into the reproductive performance and larval rearing of the Brown shrimp, Farfantepenaeus aztecus, using closed recirculating systems  

E-print Network

) ___________________________ ___________________________ Delbert M. Gatlin III Joe M. Fox (Member) (Member) ___________________________ ___________________________ Abdul-Mehdi S. Ali... iii ABSTRACT Investigations into the Reproductive Performance and Larval Rearing of the Brown Shrimp, Farfantepenaeus aztecus, Using Closed Recirculating Systems. (December 2004) Ryan Leighton Gandy, B.S., University of Charleston; M.S...

Gandy, Ryan Leighton

2005-02-17

298

Transport behavior of surrogate biological warfare agents in a simulated landfill: effect of leachate recirculation and water infiltration.  

PubMed

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. PMID:20973546

Saikaly, Pascal E; Hicks, Kristin; Barlaz, Morton A; de Los Reyes, Francis L

2010-11-15

299

High ratio recirculating gas compressor  

DOEpatents

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.

Weinbrecht, John F. (601 Oakwood Pl., NE., Albuquerque, NM 87123)

1989-01-01

300

High ratio recirculating gas compressor  

DOEpatents

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.

Weinbrecht, J.F.

1989-08-22

301

Generating efficiency and NO x emissions of a gas engine generator fueled with a biogas–hydrogen blend and using an exhaust gas recirculation system  

Microsoft Academic Search

This paper investigates the generating efficiency and NOx emissions of a gas engine generator with a low-pressure loop exhaust gas recirculation system, fueled by a model biogas. Experiments for improving the generating efficiency and reducing NOx emissions were conducted, utilizing optimum spark timings based on the maximum generating efficiencies with varying exhaust gas recirculation (EGR) rates. The test results show

Kyungtaek Lee; Taesoo Kim; Hyoseok Cha; Soonho Song; Kwang Min Chun

2010-01-01

302

Optimal white water and broke recirculation policies in paper mills via jump linear quadratic control  

Microsoft Academic Search

With the increasing closure of white water circuits in paper mills, breaks in the sheet of paper have become a system-wide disturbance. Upon recognizing that such breaks can be modeled as a Markov chain type of process which, when interacting with the continuous mill dynamics, yields a jump Markov model, jump linear theory is proposed as a means of constructing

Maryam Khanbaghi; Roland P. Malhamé; Michel Perrier

2002-01-01

303

Development of high-efficiency molecular adsorbent recirculating system: preliminary report.  

PubMed

Molecular Adsorbent Recirculating System (MARS) is a liver support system widely employed in the treatment of liver failure. The method is normally well tolerated. To develop a liver support system combining high efficiency and tolerability, we modified the MARS albumin circuit with the insertion of double adsorption units in parallel. Four patients have been treated with this modified method (high-efficiency MARS, HE MARS): two had very high serum bilirubin and two had very high total bile acids. After a single MARS session bilirubin was reduced more with HE MARS than standard MARS (from 27.6 to 52.3% in patient A and from 27.9 to 49.1% in patient B), and bile acid reduction increased from 40 to 59.8% in patient C and from 39.9 to 60% in patient D. The results of this preliminary investigation in only a very small number of patients do support the possibility of developing a liver support system that combines good tolerability and high efficacy. PMID:24392970

Marangoni, Roberto; Bellati, Giorgio; Castelli, Alessandro; Romagnoli, Elisabetta

2014-10-01

304

Review article Disinfestation of recirculating nutrient solutions  

E-print Network

Review article Disinfestation of recirculating nutrient solutions in greenhouse horticulture David suppression, but few products are commercially available. recirculation / disinfestation / hydroponics The majority of greenhouse crops are grown using artificial substrates in hydroponic systems. These sub

Boyer, Edmond

305

Thromboelastography to Monitor Clotting/Bleeding Complications in Patients Treated with the Molecular Adsorbent Recirculating System  

PubMed Central

Background. The Molecular Adsorbent Recirculating System (MARS) has been shown to clear albumin-bound toxins from patients with liver failure but might cause bleeding complications potentially obscuring survival benefits. We hypothesized that monitoring clotting parameters and bed-side thromboelastography allows to reduce bleeding complications. Methods. Retrospective analysis of 25 MARS sessions during which clotting parameters were monitored by a standardized protocol. Results. During MARS therapy median INR increased significantly from 1.7 to 1.9 platelet count and fibrinogen content decreased significantly from 57?fL?1 to 42?fL?1 and 2.1?g/L to 1.5?g/L. Nine relevant complications occurred: the MARS system clotted 6 times 3 times we observed hemorrhages. Absent thrombocytopenia and elevated plasma fibrinogen predicted clotting of the MARS system (ROC 0.94 and 0.82). Fibrinolysis, detected by thromboelastography, uniquely predicted bleeding events. Conclusion. Bed-side thromboelastography and close monitoring of coagulation parameters can predict and, therefore, help prevent bleeding complications during MARS therapy. PMID:21527982

Bachli, Esther B.; Bosiger, Jorg; Bechir, Markus; Stover, John F.; Stocker, Reto; Maggiorini, Marco; Renner, Eberhard L.; Mullhaupt, Beat; Schuepbach, Reto A.

2011-01-01

306

Ammonia-oxidizing archaea and nitrite-oxidizing nitrospiras in the biofilter of a shrimp recirculating aquaculture system.  

PubMed

This study analysed the nitrifier community in the biofilter of a zero discharge, recirculating aquaculture system (RAS) for the production of marine shrimp in a low density (low ammonium production) system. The ammonia-oxidizing populations were examined by targeting 16S rRNA and amoA genes of ammonia-oxidizing bacteria (AOB) and archaea (AOA). The nitrite-oxidizing bacteria (NOB) were investigated by targeting the 16S rRNA gene. Archaeal amoA genes were more abundant in all compartments of the RAS than bacterial amoA genes. Analysis of bacterial and archaeal amoA gene sequences revealed that most ammonia oxidizers were related to Nitrosomonas marina and Nitrosopumilus maritimus. The NOB detected were related to Nitrospira marina and Nitrospira moscoviensis, and Nitrospira marina-type NOB were more abundant than N. moscoviensis-type NOB. Water quality and biofilm attachment media played a role in the competitiveness of AOA over AOB and Nitrospira marina-over N. moscoviensis-type NOB. PMID:22775980

Brown, Monisha N; Briones, Aurelio; Diana, James; Raskin, Lutgarde

2013-01-01

307

Presence of lactobacilli in the intestinal content of freshwater fish from a river and from a farm with a recirculation system.  

PubMed

Lactobacilli are Gram-positive and catalase negative rods commonly found in lactic acid fermented foods and in the gastrointestinal tract of mammals and birds. Few studies have described lactobacilli in freshwater fish. We analysed the presence of lactobacilli in the intestines of young and adult freshwater fish inhabiting a river environment and from fish reared in an aquaculture unit with a water recirculation system. Various species of lactobacilli were present in relatively high number in the intestines of edible fresh water fish from the river, especially in the warm season but in low numbers in the cold season. Lactobacilli were scarcely found in the intestines of edible farmed fish reared in a recirculation system in warm water. Lactobacilli are reported for the first time from the intestines of wild European eel, perch, rudd, ruffe, bleak, silver bream, chub, somnul and farmed African catfish. The two first fishes, and the last one are highly valuable species for fisheries and aquaculture. Additionally, improved methods for storage and bacteriological analysis of fish intestinal content are described. The natural presence of lactic acid bacteria in fish may be of great interest in producing fermented fish products worldwide. PMID:16943040

Bucio, Adolfo; Hartemink, Ralf; Schrama, Johan W; Verreth, Johan; Rombouts, Frans M

2006-08-01

308

An automated recirculation aquaculture system based on fuzzy logic control for aquaculture production of tilapia ( Oreochromis niloticus )  

Microsoft Academic Search

The development of an automated recirculation aquaculture system (ARAS) is presented here. The production system facility\\u000a was built in a 672-m2 polyethylene greenhouse using four 20-m3 tanks, each of which was stocked with 1,000 tilapia (O. niloticus). The growth of the fish was evaluated from a starting weight of 2 g to a final average weight of 418 g, during a production

Genaro M. Soto-Zarazúa; Rocío Peniche-Vera; Enrique Rico-García; Manuel Toledano-Ayala; Rosalía Ocampo-Velázquez; Gilberto Herrera-Ruiz

309

Solids removal from a coldwater recirculating system—comparison of a swirl separator and a radial-flow settler  

Microsoft Academic Search

Solids removal across two settling devices, i.e., a swirl separator and a radial-flow settler, and across a microscreen drum filter was evaluated in a fully recirculating system containing a single 150m3 ‘Cornell-type’ dual-drain tank during the production of food-size Arctic char and rainbow trout. The flow through the culture tank was 4500–4800L\\/min. Approximately 92–93% of the system flow exited through

John Davidson; Steven T. Summerfelt

2005-01-01

310

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

PubMed

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. Bacteria were produced in growth reactors under different conditions: 7 h hydraulic retention time (HRT) vs. 2 h, sodium acetate vs. molasses, and ammonia vs. nitrate. The community of the drumfilter effluent was different from those found in the reactors. However, all major community components were present in the effluent and reactor broths. HRT influenced the bacteria community, resulting in a DGGE profile dominated by a band corresponding to an Acinetobacter sp.-related population at 2 h HRT compared to 7 h HRT, where bands indicative of alpha-proteobacterial populations most closely related to Rhizobium and Shinella spp. were most abundant. Molasses influenced the bacterial community. It was dominated by an Aquaspirillum serpens-related population. Providing total ammonia nitrogen (TAN) in addition to nitrate led to the occurrence of bacteria close to Sphaerotilus spp., Flavobacterium mizutaii and Jonesia spp. It was concluded from these results that a 6-7 h HRT is recommended, and that the type of substrate is less important, and results in communities with a comparably low pathogenic risk. PMID:17371322

Schneider, Oliver; Chabrillon-Popelka, Mariana; Smidt, Hauke; Haenen, Olga; Sereti, Vasiliki; Eding, Ep H; Verreth, Johan A J

2007-05-01

311

Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary Formations  

SciTech Connect

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.

Mike Bruno; Russell L. Detwiler; Kang Lao; Vahid Serajian; Jean Elkhoury; Julia Diessl; Nicky White

2012-09-30

312

Anaerobic Ammonium-Oxidizing (Anammox) Bacteria and Associated Activity in Fixed-Film Biofilters of a Marine Recirculating Aquaculture System  

Microsoft Academic Search

Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aqua- culture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and

Yossi Tal; Joy E. M. Watts; Harold J. Schreier

2006-01-01

313

Changes in microbial communities associated with the conditioning of filter material in recirculating aquaculture systems of the pufferfish Takifugu rubripes  

Microsoft Academic Search

We investigated changes in microflora associated with the conditioning of filter material in a recirculating aquaculture system for the culture of the pufferfish Takifugu rubripes using a clone library method of partial 16S rRNA gene sequences. Total bacteria on the pebbles used as filter material increased from 8.4×109 cells g?1 at peak ammonia concentrations (8 days) to 1.3×1010 cells g?1 at

Shiro Itoi; Ayako Niki; Haruo Sugita

2006-01-01

314

Production Characteristics and Body Composition of Juvenile Cobia Fed Three Different Commercial Diets in Recirculating Aquaculture Systems  

Microsoft Academic Search

The effect of feeding three commercial diets on production characteristics and body composition of juvenile cobia Rachycentron canadum reared using recirculating aquaculture systems (RASs) was assessed in a 56-d growth trial. Juvenile cobia (mean weight ± SE, 29.2 ± 0.7 g) were stocked into three 8-m tanks in each of four RASs at an initial density of 1.2 kg\\/m. After

Charles R. Weirich; Paul S. Wills; Richard M. Baptiste; Marty A. Riche

2010-01-01

315

Nutrient cycle and sludge production during different stages of red tilapia ( Oreochromis sp.) growth in a recirculating aquaculture system  

Microsoft Academic Search

The nutrient cycle of input feed and sludge production was evaluated for five stages of red tilapia growth in a recirculating aquaculture system. Five weight groups of red tilapia, 20±0.00 (20), 39.70±0.44 (40), 80.38±0.41(80), 113.62±1.92 (120), and 177.67±1.81 (180) g in triplicates were selected as treatments and randomly introduced to the experimental units (75 fishes\\/unit) and cultured for a 3-week

Gholamreza Rafiee; Che Roos Saad

2005-01-01

316

Passive containment cooling system (PCCS) response with Drywell Gas Recirculation System (DGRS) activated during a postulated Loss of Coolant Accident (LOCA)  

Microsoft Academic Search

Passive Containment Cooling Systems (PCCS) are characterizing the design of several advanced LWR such as SBWR, ESBWR, ABWR-II, etc. These systems should ensure the mitigation of postulated accidents both under Design Basic Accident (DBA) and Beyond DBA (BDBA) conditions. Some ALWR designs integrated in the PCCS a system called Drywell Gas Recirculation System (DGRS). The DGRS works like a fan,

Domenico Paladino; Joerg Dreier

2011-01-01

317

[Analysis of the changes of microbial community structure on bio-carrier of recirculating aquaculture systems (RAS)].  

PubMed

In order to study the variation of microbial community structure and the mechanism of denitrification on bio-carrier in recirculating aquaculture systems (RAS) during the periods of bio-film formation and operation the systems, traditional microbiological methods were applied to count the quantity of heterotrophic bacteria, ammonia oxidize bacteria and nitrite oxidize bacteria. The amplified products of variable V3 region of bacterial 16S rDNA were separated by using denaturing gradient gel electrophoresis (DGGE). And bacterial community DNA fingerprint was obtained. The sequences retrieved from the DGGE bands were used for homology analysis and construction of phylogenetic tree. It presented a trend that the quantity of the three types of bacteria increased gradually to a top and then fallen slowly to a stable level. The composition of microbial community of bio-carrier was very abundant in all periods, and the Shannon index was 1.53, 1.44, 1.57, 1.08, 1.27 and 1.30, respectively. During different periods, there was a certain shift in the microbial community structure, while the C(s) value (similar index) in two adjacent periods was high, indicating the variation and succession of the microbial community was slow and regular. Several bacteria had an effect on removal of pollutants for farming water and the effluent water quality could meet the requirements of high-density culture. Among them, Proteobacteria and Flavobacteria were main communities. The Nitrosomonas and some other facultative anaerobic bacteria (Flavobacteriaceae bacterium) were identified, which indicated that there may be coexisted pathways of nitrification and denitrification in bio-filter. PMID:21404692

Zhang, Hai-Geng; Ma, Shao-Sai; Li, Qiu-Fen; Fu, Xue-Jun; Zhang, Yan; Qu, Ke-Ming

2011-01-01

318

Hematologic and plasma biochemical values of healthy hybrid tilapia (Oreochromis aureus x Oreochromis nilotica) maintained in a recirculating system.  

PubMed

Tilapia are cultured worldwide and are increasing in popularity among aquaculturalists in the United States; however, data regarding normal health parameters are limited. Few hematologic and plasma biochemical values of clinically normal tilapia have been reported, but these data may be key for identifying and managing disease issues in recirculating systems. Therefore, blood was collected from clinically normal hybrid tilapia (Oreochromis aureus x Oreochromis nilotica) housed in recirculating systems for the purpose of establishing normal hematologic and plasma biochemical reference ranges. Using standard clinical techniques the following hematologic values were determined: packed cell volume, plasma protein, leukocyte counts, leukocyte differentials, and thrombocyte counts. Additionally, the following plasma biochemical values were determined: albumin, total protein, globulins, albumin/globulin ratio, aspartate aminotransferase, alkaline phosphatase, glucose, uric acid, calcium, phosphorus, magnesium, sodium, potassium, chloride, urea nitrogen, and creatinine. The condition of the sample was also noted (lipemic, hemolysis, and icterus). The reference ranges reported in this study can be used in the management of cultured tilapia in recirculating systems. PMID:17939351

Mauel, Michael J; Miller, Debra L; Merrill, Anita L

2007-09-01

319

Treatment of trichodiniasis in eel ( Anguilla anguilla) reared in recirculation systems in Denmark: alternatives to formaldehyde  

Microsoft Academic Search

Treatment of trichodiniasis in recirculation eel farms using formalin (37%) has been found insufficient. We have screened 30 different chemical substances for efficacy against natural infections with trichodinids (Trichodina jadranica) on skin and gills of eels. The following substances showed high parasiticidal effect: acriflavin (25 ppm), bithionol (0.1 ppm), chloramine T (50 ppm), Detarox AP® (45 ppm), malachite green (1

Hans C. K Madsen; Kurt Buchmann; Stig Mellergaard

2000-01-01

320

Cost-utility of molecular adsorbent recirculating system treatment in acute liver failure  

PubMed Central

AIM: To determine the short-term cost-utility of molecular adsorbent recirculating system (MARS) treatment in acute liver failure (ALF). METHODS: A controlled retrospective study was conducted with 90 ALF patients treated with MARS from 2001 to 2005. Comparisons were made with a historical control group of 17 ALF patients treated from 2000 to 2001 in the same intensive care unit (ICU) specializing in liver diseases. The 3-year outcomes and number of liver transplantations were recorded. All direct liver disease-related medical expenses from 6 mo before to 3 years after ICU treatment were determined for 31 MARS patients and 16 control patients. The health-related quality of life (HRQoL) before MARS treatment was estimated by a panel of ICU doctors and after MARS using a mailed 15D (15-dimensional generic health-related quality of life instrument) questionnaire. The HRQoL, cost, and survival data were combined and the incremental cost/quality-adjusted life years (QALYs) was calculated. RESULTS: In surviving ALF patients, the health-related quality of life after treatmeant was generally high and comparable to the age- and gender-matched general Finnish population. Compared to the controls, the average cost per QALY was considerably lower in the MARS group (64 732€ vs 133 858€) within a timeframe of 3.5 years. The incremental cost of standard medical treatment alone compared to MARS was 10 928€, and the incremental number of QALYs gained by MARS was 0.66. CONCLUSION: MARS treatment combined with standard medical treatment for ALF in an ICU setting is more cost-effective than standard medical treatment alone. PMID:20458759

Kantola, Taru; Maklin, Suvi; Koivusalo, Anna-Maria; Rasanen, Pirjo; Rissanen, Anne; Roine, Risto; Sintonen, Harri; Hockerstedt, Krister; Isoniemi, Helena

2010-01-01

321

Molecular Adsorbent Recirculating System (MARS(®)) removal of piperacillin/tazobactam in a patient with acetaminophen-induced acute liver failure.  

PubMed

The objective of this study was to illustrate the pharmacokinetic removal of piperacillin/tazobactam in an anuric patient on Molecular Adsorbent Recirculating System (MARS(®)). The patient was a 32-year-old woman who presented to a medical intensive care unit with acute liver failure secondary to an acetaminophen overdose. While awaiting transplant, she was started on MARS therapy as a bridge to liver transplant and empirically started on piperacillin/tazobactam therapy. MARS is an extracorporeal hemofiltration device, which incorporates a continuous venovenous hemofiltration (CVVHD) machine linked to an albumin-enriched dialysate filter to normalize excess electrolytes, metabolic waste, and protein-bound toxins. In addition to protein-bound waste, MARS removes water-soluble, low molecular-weight molecules. The patient received piperacillin/tazobactam 4.5 g infused intravenously over 3 h. A steep decline in serum levels occurred between hours 4 and 6 while MARS continued and no antibiotic was infused. The elimination rate constant (k(e)) for the removal of piperacillin in this patent was 0.453 h(-1) and the half-life (?) was 1.53 h. The k(e) was 2.9-fold higher than with CVVHD alone and the ? was 3.7-fold shorter. Low levels of piperacillin are achieved during MARS therapy, but in the treatment of more resistant organisms, such as Pseudomonas aeruginosa, these low levels may not be adequate to achieve bactericidal activity. Drug levels following a standard infusion of 30 min would likely be even lower. Formalized pharmacokinetic studies of piperacillin/tazobactam removal in patients on MARS therapy are necessary to make clear dosing recommendations. PMID:23279615

Ruggero, M A; Argento, A C; Heavner, M S; Topal, J E

2013-04-01

322

Growth performance of disk abalone Haliotis discus hannai in pilot- and commercial-scale recirculating aquaculture systems  

Microsoft Academic Search

The study investigated the growth performance of abalone from juvenile to marketable size in a commercial-scale recirculating\\u000a aquaculture system. The rearing system consisted of 12 raceways (4.0 × 0.8 × 0.6 m) with a protein skimmer and a submerged\\u000a biofilter for juveniles and 10 raceways (6.6 × 1.3 × 0.6 m) with a protein skimmer and a trickling biofilter for on-growing.\\u000a Sea mustard (Undaria pinnatifida) and kelp (Laminaria japonica) were

Pyong-Kih Kim; Jae-Yoon Jo

2008-01-01

323

Ozone's effects on power-law particle size distribution in recirculating aquaculture systems  

Microsoft Academic Search

A power law model for particle size distributions has been applied by several researchers to aquacultural and aquatic systems Rueter and Johnson [Aquacult. Eng. 14 (1995) 123] demonstrated that ozonation of trout hatchery water increased the proportion of large particles in the water. Summerfelt et al. [Aquaculture 158 (1997) 57] speculated that this increase in particle size led to their

Valdis Krumins; James M. Ebeling; Fred Wheaton

2001-01-01

324

Performance evaluation of radial\\/vertical flow clarification applied to recirculating aquaculture systems  

Microsoft Academic Search

A prototype radial\\/vertical clarifier with 60° cone bottom was built and evaluated for application in recirculating aquaculture. Samples were analyzed for particle size distribution using a laser diffraction particle analyzer (Mastersizer S, Malvern Instruments Ltd., Worcestershire, UK) and total suspended solids (TSS) to determine the effectiveness of the clarifier. Surface area calculated mean influent and effluent particle diameters were 81.12±1.57?m

William Johnson; Shulin Chen

2006-01-01

325

Soil nitrifying enrichments as biofilter starters in intensive recirculating saline water aquaculture  

E-print Network

. This will improve water quality and consequently aquatic animal production. D 2003 Elsevier Science B.V. All rights-8486/03/$ - see front matter D 2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0044-8486(03)00067-X

Gross, Amit

326

Anaerobic ammonium-oxidizing (anammox) bacteria and associated activity in fixed-film biofilters of a marine recirculating aquaculture system.  

PubMed

Microbial communities in the biological filter and waste sludge compartments of a marine recirculating aquaculture system were examined to determine the presence and activity of anaerobic ammonium-oxidizing (anammox) bacteria. Community DNA was extracted from aerobic and anaerobic fixed-film biofilters and the anaerobic sludge waste collection tank and was analyzed by amplifying 16S rRNA genes by PCR using anammox-selective and universal GC-clamped primers. Separation of amplified PCR products by denaturing gradient gel electrophoresis and sequencing of the different phylotypes revealed a diverse biofilter microbial community. While Planctomycetales were found in all three communities, the anaerobic denitrifying biofilters contained one clone that exhibited high levels of sequence similarity to known anammox bacteria. Fluorescence in situ hybridization studies using an anammox-specific probe confirmed the presence of anammox Planctomycetales in the microbial biofilm from the denitrifying biofilters, and anammox activity was observed in these biofilters, as detected by the ability to simultaneously consume ammonia and nitrite. To our knowledge, this is the first identification of anammox-related sequences in a marine recirculating aquaculture filtration system, and our findings provide a foundation for incorporating this important pathway for complete nitrogen removal in such systems. PMID:16597996

Tal, Yossi; Watts, Joy E M; Schreier, Harold J

2006-04-01

327

Bacterially mediated removal of phosphorus and cycling of nitrate and sulfate in the waste stream of a "zero-discharge" recirculating mariculture system.  

PubMed

Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (?15 mM), were removed by microbial respiration in the sludge resulting in a sulfide accumulation of up to 3 mM. Modelling of the observed S and O isotopic ratios in the surface sludge suggested that, with time, major respiration processes shifted from heterotrophic nitrate and sulfate reduction to autotrophic nitrate reduction. The much higher inorganic P content of the sludge relative to the fish feces is attributed to conversion of organic P to authigenic apatite. This conclusion is supported by: (a) X-ray diffraction analyses, which pointed to an accumulation of a calcium phosphate mineral phase that was different from P phases found in the feces, (b) the calculation that the pore waters of the sludge were highly oversaturated with respect to hydroxyapatite (saturation index = 4.87) and (c) there was a decrease in phosphate (and in the Ca/Na molar ratio) in the pore waters simultaneous with an increase in ammonia showing there had to be an additional P removal process at the same time as the heterotrophic breakdown of organic matter. PMID:24657541

Krom, M D; Ben David, A; Ingall, E D; Benning, L G; Clerici, S; Bottrell, S; Davies, C; Potts, N J; Mortimer, R J G; van Rijn, J

2014-06-01

328

Phosphatase activity and specific methanogenic activity in an anaerobic reactor treating sludge from a brackish recirculation aquaculture system.  

PubMed

Anaerobic treatment of high salinity sludge from marine/brackish recirculation aquaculture systems is potentially limited by inhibition of enzymatic activities and cell lysis resulting from high osmotic pressures. To further address these limitations the following investigations were conducted: effect of salinity on phosphatase activity (PA), soluble microbial products (SMP) production, and presence of extracellular polymeric substances (EPS); effect of iron (III) chloride (FeCl3) on PA and specific methanogenic activity (SMA); effect of addition of the compatible solute glycine betaine (GB) and potassium on PA, as well as on SMP and EPS production, all under saline conditions. The results show that salinity has different effects on PA of anaerobes under starvation and feeding conditions. FeCl3 increased the SMA of the sludge by 22.5% at 100 mg FeCl3/L compared with a control group (0 mg FeCl3/L). Furthermore, results of analysis of variance tests show that betaine increased the polysaccharide content of EPS and polypeptide content of SMP. However, addition of 1 mM potassium chloride did not show a significant effect on EPS and SMP composition. In conclusion, anaerobic digestion of salty sludges from a brackish aquaculture recirculation system may not be negatively affected by FeCl3 addition to concentrate waste streams, whereas GB boosts the production of SMP and EPS. PMID:23863432

Zhang, Xuedong; Ferreira, Rui B; Spanjers, Henri; van Lier, Jules B

2013-01-01

329

Un formalisme de systemes a sauts pour la recirculation optimale des casses dans une machine a papier  

NASA Astrophysics Data System (ADS)

Increasing closure of white water circuits is making mill productivity and quality of paper produced increasingly affected by the occurrence of paper breaks. In this thesis the main objective is the development of white water and broke recirculation policies. The thesis consists of three main parts, respectively corresponding to the synthesis of a statistical model of paper breaks in a paper mill, the basic mathematical setup for the formulation of white water and broke recirculation policies in the mill as a jump linear quadratic regulation problem, and finally the tuning of the control law based on first passage-time theory, and its extension to the case of control sensitive paper break rates. More specifically, in the first part a statistical model of paper machine breaks is developed. We start from the hypothesis that the breaks process is a Markov chain with three states: the first state is the operational one, while the two others are associated with the general types of paper-breaks that can take place in the mill (wet breaks and dry breaks). The Markovian hypothesis is empirically validated. We also establish how paper-break rates are correlated with machine speed and broke recirculation ratio. Subsequently, we show how the obtained Markov chain model of paper-breaks can be used to formulate a machine operating speed parameter optimization problem. In the second part, upon recognizing that paper breaks can be modelled as a Markov chain type of process which, when interacting with the continuous mill dynamics, yields a jump Markov model, jump linear theory is proposed as a means of constructing white water and broke recirculation strategies which minimize process variability. Reduced process variability comes at the expense of relatively large swings in white water and broke tanks level. Since the linear design does not specifically account for constraints on the state-space, under the resulting law, damaging events of tank overflow or emptiness can occur. A heuristic simulation-based approach is proposed to choose the performance measure design parameters to keep the mean time between incidents of fluid in broke and white water tanks either overflowing, or reaching dangerously low levels, sufficiently long. In the third part, a methodology, mainly founded on the first passage-time theory of stochastic processes, is proposed to choose the performance measure design parameters to limit process variability while accounting for the possibility of undesirable tank overflows or tank emptiness. The heart of the approach is an approximation technique for evaluating mean first passage-times of the controlled tanks levels. This technique appears to have an applicability which largely exceeds the problem area it was designed for. Furthermore, the introduction of control sensitive break rates and the analysis of the ensuing control problem are presented. This is to account for the experimentally observed increase in breaks concomitant with flow rate variability.

Khanbaghi, Maryam

330

Comparison of hydroponic crop production techniques in a recirculating fish culture system  

E-print Network

designed after accepted horticultural techniques. The system was stocked with fish and operated for six weeks before cucumbers (Cucumis sativa) were planted. Ammonia, nitrite, nitrate, phosphate, pH, plant height, fish weight, temperature... in nitrite nitrogen concentration across hydroponic treatments 39 Figure 9. Mean nitrite nitrogen concentration at various locations in the system in order of water flow for weeks five through seven 41 Figure 10. Mean change in nitrate nitrogen...

Wren, Steven Whitaker

2012-06-07

331

Trichodina sp. (Ciliophora: Peritrichida) in eel Anguilla anguilla in recirculation systems in denmark: host-parasite relations.  

PubMed

Farmed eel cultured in recirculation systems in Denmark were found infected by Trichodina jadranica Raabe, 1958. Associations between parasite abundance and fish size was examined in 2 different production systems. In one system, stocked with relatively well-nourished eels (3 to 31 g), most of the parasites (66%) were found on the dorsal part on the skin and relatively few were found on the gills (approx. 8%). The infection level was significantly positively correlated both with fish weight and length. In the other system, stocked with relatively malnourished small eels (0.5 to 4 g), significantly more parasites (0.06 +/- 0.02 [SD]) were present on fish with a low condition factor than on fish with a higher condition factor (0.13 +/- 0.01 [SD]). In this eel stock the vast majority of the trichodines were found on the gills. PMID:11023254

Madsen, H C; Buchmann, K; Mellergaard, S

2000-08-31

332

Removal of naphthalene from recirculated wash oil  

SciTech Connect

A bleed stream from the recirculating wash oil in a final cooling system for coke oven gas is centrifugally separated into a waste water stream, a sludge stream and a clean, dry oil stream which is substantially free of solids and has a water content less than 0.5% (Wt.). The clean, dry oil stream is heated to less than about 160/sup 0/C., preferably 125/sup 0/-135/sup 0/C, before entering a naphthalene stripper-wash oil still.

Burcaw, K.R.; Watkins, R.E.

1981-09-01

333

Control of a turbocharged Diesel engine fitted with high pressure and low pressure exhaust gas recirculation systems  

Microsoft Academic Search

Exhaust gas recirculation is an effective way for reducing nitric oxides emissions in Diesel engine achieving low temperature combustion (LTC). Two strategies can be applied to recirculate burnt gas in a turbocharged Diesel engine using the high pressure loop or the low pressure loop. This paper describes a generic model based control structure for Diesel engines with dual-loop exhaust gas

Olivier Grondin; Philippe Moulin; Jonathan Chauvin

2009-01-01

334

40 CFR 1065.127 - Exhaust gas recirculation.  

Code of Federal Regulations, 2011 CFR

...CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use the exhaust gas recirculation (EGR) system installed with the engine or one that represents a typical in-use configuration. This...

2011-07-01

335

40 CFR 1065.127 - Exhaust gas recirculation.  

Code of Federal Regulations, 2010 CFR

...CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use the exhaust gas recirculation (EGR) system installed with the engine or one that represents a typical in-use configuration. This...

2010-07-01

336

40 CFR 1065.127 - Exhaust gas recirculation.  

Code of Federal Regulations, 2013 CFR

...CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use the exhaust gas recirculation (EGR) system installed with the engine or one that represents a typical in-use configuration. This...

2013-07-01

337

40 CFR 1065.127 - Exhaust gas recirculation.  

Code of Federal Regulations, 2012 CFR

...CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use the exhaust gas recirculation (EGR) system installed with the engine or one that represents a typical in-use configuration. This...

2012-07-01

338

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

E-print Network

Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090, China b MOE Key Laboratory recirculation of 698 ± 10 mW/m2 (50 mM PBS) and 508 ± 11 mW/m2 (25 mM PBS). The salt solution (20 g/L Na to the anode, and a cation exchange membrane (CEM) next to the cathode, with the salt solution in the middle

339

Application of Chemical Coagulation Aids for the Removal of Suspended Solids (TSS) and Phosphorus from the Microscreen Effluent Discharge of an Intensive Recirculating Aquaculture System  

Microsoft Academic Search

An evaluation of two commonly used coagulation–flocculation aids (alum and ferric chloride) was conducted to determine optimum conditions for treating the backwash effluent from microscreen filters in an intensive recirculating aquaculture system. Tests were carried out to evaluate the dosages and conditions (mixing and flocculation stirring speeds, durations, and settling times) required to achieve optimum waste capture. The orthophosphate removal

James M. Ebeling; Sarah R. Ogden; Philip L. Sibrell; Kata L. Rishel

2004-01-01

340

Role of Hot Water System Design on Factors Influential to Pathogen Regrowth: Temperature, Chlorine Residual, Hydrogen Evolution, and Sediment  

PubMed Central

Abstract Residential water heating is linked to growth of pathogens in premise plumbing, which is the primary source of waterborne disease in the United States. Temperature and disinfectant residual are critical factors controlling increased concentration of pathogens, but understanding of how each factor varies in different water heater configurations is lacking. A direct comparative study of electric water heater systems was conducted to evaluate temporal variations in temperature and water quality parameters including dissolved oxygen levels, hydrogen evolution, total and soluble metal concentrations, and disinfectant decay. Recirculation tanks had much greater volumes of water at temperature ranges with potential for increased pathogen growth when set at 49°C compared with standard tank systems without recirculation. In contrast, when set at the higher end of acceptable ranges (i.e., 60°C), this relationship was reversed and recirculation systems had less volume of water at risk for pathogen growth compared with conventional systems. Recirculation tanks also tended to have much lower levels of disinfectant residual (standard systems had 40–600% higher residual), 4–6 times as much hydrogen, and 3–20 times more sediment compared with standard tanks without recirculation. On demand tankless systems had very small volumes of water at risk and relatively high levels of disinfectant residual. Recirculation systems may have distinct advantages in controlling pathogens via thermal disinfection if set at 60°C, but these systems have lower levels of disinfectant residual and greater volumes at risk if set at lower temperatures. PMID:24170969

Brazeau, Randi H.; Edwards, Marc A.

2013-01-01

341

Molecular analysis of bacterial communities and detection of potential pathogens in a recirculating aquaculture system for Scophthalmus maximus and Solea senegalensis.  

PubMed

The present study combined a DGGE and barcoded 16S rRNA pyrosequencing approach to assess bacterial composition in the water of a recirculating aquaculture system (RAS) with a shallow raceway system (SRS) for turbot (Scophthalmus maximus) and sole (Solea senegalensis). Barcoded pyrosequencing results were also used to determine the potential pathogen load in the RAS studied. Samples were collected from the water supply pipeline (Sup), fish production tanks (Pro), sedimentation filter (Sed), biofilter tank (Bio), and protein skimmer (Ozo; also used as an ozone reaction chamber) of twin RAS operating in parallel (one for each fish species). Our results revealed pronounced differences in bacterial community composition between turbot and sole RAS, suggesting that in the systems studied there is a strong species-specific effect on water bacterial communities. Proteobacteria was the most abundant phylum in the water supply and all RAS compartments. Other important taxonomic groups included the phylum Bacteriodetes. The saltwater supplied displayed a markedly lower richness and appeared to have very little influence on bacterial composition. The following potentially pathogenic species were detected: Photobacterium damselae in turbot (all compartments), Tenacibaculum discolor in turbot and sole (all compartments), Tenacibaculum soleae in turbot (all compartments) and sole (Pro, Sed and Bio), and Serratia marcescens in turbot (Sup, Sed, Bio and Ozo) and sole (only Sed) RAS. Despite the presence of these pathogens, no symptomatic fish were observed. Although we were able to identify potential pathogens, this approach should be employed with caution when monitoring aquaculture systems, as the required phylogenetic resolution for reliable identification of pathogens may not always be possible to achieve when employing 16S rRNA gene fragments. PMID:24278329

Martins, Patrícia; Cleary, Daniel F R; Pires, Ana C C; Rodrigues, Ana Maria; Quintino, Victor; Calado, Ricardo; Gomes, Newton C M

2013-01-01

342

Isolation of Legionella pneumophila from water systems: methods and preliminary results  

Microsoft Academic Search

A preliminary survey of water systems in hospitals and hotels showed that Legionella pneumophila may be found in water storage and distribution systems as well as in the recirculating cooling water of air-conditioning plants. Altogether 42 isolates of L pneumophila were made from 31 establishments, six of which were associated with cases of legionnaires' disease but in 25 of which

J O Tobin; R A Swann; C L Bartlett

1981-01-01

343

Water Systems  

NSDL National Science Digital Library

Water cycle concepts and basics including the distribution of water on the planet in oceans, rivers and lakes, glaciers and atmosphere. Defines basic terms: states of water, evaporation, transpiration, condensation, precipitation, melting. Good illustrations, maps and photos. Excellent list itemizes human uses and impacts on water and the water cycle. Links to more detailed references are provided, case studies illustrate current concerns and issues in Ontario, Canada.

344

Technology development for recirculating heavy-ion accelerators  

Microsoft Academic Search

Summary  The «recirculator», a recirculating heavy-ion accelerator, has been identified as a promising approach for an inertial-fusion\\u000a driver. System studies have been conducted to evaluate the recirculator on the basis of feasibility and cost. The recirculator\\u000a has been shown to have significant cost advantages over other potential driver schemes, but some of the performance requirements\\u000a exceed the capabilities of present technology.

M. A. Newton; H. C. Kirbie

1993-01-01

345

Peracetic acid degradation and effects on nitrification in recirculating aquaculture systems  

Microsoft Academic Search

Peracetic acid (PAA) is a powerful disinfectant with a wide spectrum of antimicrobial activity. PAA and hydrogen peroxide (HP) degrade easily to oxygen and water and have potential to replace formalin in aquaculture applications to control fish pathogens, for example the ectoparasite, Ichthyophthirius multifiliis.We studied water phase PAA and HP decay in three aquaculture situations, i) batch experiments with two

Lars-Flemming Pedersen; Per B. Pedersen; Jeppe L. Nielsen; Per H. Nielsen

2009-01-01

346

Recirculation System for Geothermal Energy Recovery in Sedimentary Formations: Laboratory Experiments and Numerical Simulations  

NASA Astrophysics Data System (ADS)

Geothermal energy resources are more widespread than previously thought and have the potential for providing a significant amount of sustainable clean energy worldwide. In particular, hot permeable sedimentary formations provide many advantages over traditional geothermal recovery and enhanced geothermal systems in low permeability crystalline formations. These include: (1) eliminating the need for hydraulic fracturing, (2) significant reduction in risk for induced seismicity, (3) reducing the need for surface wastewater disposal, (4) contributing to decreases in greenhouse gases, and (5) potential use for CO2 sequestration. Advances in horizontal drilling, completion, and production technology from the oil and gas industry can now be applied to unlock these geothermal resources. Here, we present experimental results from a laboratory scale circulation system and numerical simulations aimed at quantifying the heat transfer capacity of sedimentary rocks. Our experiments consist of fluid flow through a saturated and pressurized sedimentary disc of 23-cm diameter and 3.8-cm thickness heated along its circumference at a constant temperature. Injection and production ports are 7.6-cm apart in the center of the disc. We used DI de-aired water and mineral oil as working fluids and explored temperatures from 20 to 150 oC and flow rates from 2 to 30 ml/min. We performed experiments on sandstone samples (Castlegate and Kirby) with different porosity, permeability and thermal conductivity to evaluate the effect of hydraulic and thermal properties on the heat transfer capacity of sediments. The producing fluid temperature followed an exponential form with time scale transients between 15 and 45 min. Steady state outflow temperatures varied between 60% and 95% of the set boundary temperature, higher percentages were observed for lower temperatures and flow rates. We used the flow and heat transport simulator TOUGH2 to develop a numerical model of our laboratory setting. Given the remarkable match between our observations and numerical results, we extended our model to explore a wider range of thermal and hydrological parameters beyond the experimental conditions. Our results prove the capability of heat transfer in sedimentary formations for geothermal energy production.) Sandstone sample with two thermally insulating Teflon caps (white discs). In and out arrows indicate the flow direction while the sample is heated along its circumference (heater not shown). B) Example of a 2D temperature distribution during injection. White x shows the location of the flow ports, inlet (left) and outlet (right). Red is the set boundary temperature and blue is the fluid temperature at the inlet.

Elkhoury, J. E.; Detwiler, R. L.; Serajian, V.; Bruno, M. S.

2012-12-01

347

Exhaust gas recirculator  

Microsoft Academic Search

An exhaust gas recirculator for an internal combustion engine having an exhaust pipe, an intake manifold and a carburetor throttle valve. The exhaust gas recirculator comprises an egr passage which makes the exhaust pipe communicate with the intake manifold, an egr controlling valve and an egr valve respectively arranged in the upper and lower portions of the egr passage. The

Suda

1983-01-01

348

A Recirculated Fish Production Unit in Combination with a Hydroponic Unit.  

National Technical Information Service (NTIS)

In two years of investigation, it has been demonstrated that it is feasible to use hydroponically grown plants to aid in maintaining water quality in a closed fish culture system supported by recirculated water. It has also been shown that the vegetable c...

W. M. Lewis, J. H. Yopp

1978-01-01

349

Performance of the seaweeds Gracilaria salicornia and Caulerpa lentillifera as biofilters in a hatchery scale recirculating aquaculture system for juvenile spotted babylons ( Babylonia areolata )  

Microsoft Academic Search

This study was conducted to determine the feasibility of using seaweeds as biofilters in a hatchery scale recirculating aquaculture\\u000a system for juvenile spotted babylons (Babylonia areolata). Two seaweeds Gracilaria salicornia and Caulerpa lentillifera were used with three initial biomass levels of each species (280, 560 and 840 g wet weight m?3). Spotted babylon with an average initial shell length of 1.32 ± 0.01 cm and body weight

Nilnaj Chaitanawisuti; Wannanee Santhaweesuk; Sirusa Kritsanapuntu

350

Development of zooplankton culture subsystem for a closed ecological recirculating aquaculture system (CERAS)  

NASA Astrophysics Data System (ADS)

Ten parthenogenetic females of Moina macrocopa were placed in small cells with different flow conditions. The cells were opened after three-days of cultivation, and the water fleas in each cell were counted. It appeared that M. macrocopa were cultured effectively in a relatively slow current, 10 cm/min., but the population growth was not significantly influenced by the difference in flow direction. Subsequent, filtration efficiencies of filters with various pore sizes were compared. Four available porous hollow-fiber membrane modules, ACP-1010, AHP-1010, PSP-103, and PMP-102 (Asahi-Kasei Corp.), were tested. The module with the larger pore size initially filtered a greater amount of water but clogged up sooner. ACP-1010, which has the smallest pores, was considered to be suitable to filter condensed algal water due to its durability and stable filtration. An improved zooplankton culture device (IZCD) was designed and constructed based on these examinations. IZCD is a 13.2L airtight device characterized by a short and thick rearing tank and alternate filtration with paired fine hollow-fiber membrane modules. It must be tested and revised to be used in research into the optimal conditions for a zooplankton culture in a closed environment.

Omori, Katsunori; Oguchi, Mitsuo; Takeuchi, Toshio

2006-01-01

351

Exhaust gas recirculation valve malfunction indicator apparatus  

Microsoft Academic Search

An internal combustion engine is provided with an exhaust gas recirculating (EGR) system containing a vacuum\\/electric switch assembly activated in response to a non-movement type malfunction of the EGR valve to energize a warning light.

1977-01-01

352

Solids removal in a recirculating aquaculture system where the majority of flow bypasses the microscreen filter  

Microsoft Academic Search

Solids capture in a sedimentation basin in the lower portion of an external standpipe was compared with solids capture by the drum filter (DF) in a commercial recycle aquaculture system (RAS) with dual-drain culture tanks equipped with sidewall and bottom-center drains. The system had a unique combination of features: sidewall drain effluent, 79% of total from the culture tank, that

Robert C. Summerfelt; Chris R. Penne

2005-01-01

353

Recirculating rotary gas compressor  

DOEpatents

A positive displacement, recirculating Roots-type rotary gas compressor is described which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits which return compressed discharge gas to the compressor housing, where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor. 12 figs.

Weinbrecht, J.F.

1992-02-25

354

Recirculating rotary gas compressor  

DOEpatents

A positive displacement, recirculating Roots-type rotary gas compressor which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits (24 and 26) which return compressed discharge gas to the compressor housing (14), where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers (10 and 12) and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor.

Weinbrecht, John F. (601 Oakwood Loop, NE., Albuquerque, NM 87123)

1992-01-01

355

Root Media Materials for Cucumber Production in Closed Recirculated Hydroponic Systems  

Microsoft Academic Search

Cucumber (Cucumis sativus L. cv. Rawa) was grown in hydroponics .for two successive seasons under glasshouse conditions to test materials in the gullies of the nutrient film technique (NFT) system. Treatments were: date-palm fibers (Leef); dried shredded date-plam leaflets (Karena), nylon threads (NT); 3-inch- PVC pipes (pipe); rock wool (RW) and the control. The Leef and Karena treatments exceeded the

M. A. Medany; M. M. Hafez; A. F. Abou-Hadid; A. S. El-Beltagy

1995-01-01

356

Establishment of a real-time PCR method for quantification of geosmin-producing Streptomyces spp. in recirculating aquaculture systems.  

PubMed

Geosmin and 2-methylisoborneol (MIB) have been associated with off-flavour problems in fish and seafood products, generating a strong negative impact for aquaculture industries. Although most of the producers of geosmin and MIB have been identified as Streptomyces species or cyanobacteria, Streptomyces spp. are thought to be responsible for the synthesis of these compounds in indoor recirculating aquaculture systems (RAS). The detection of genes involved in the synthesis of geosmin and MIB can be a relevant indicator of the beginning of off-flavour events in RAS. Here, we report a real-time polymerase chain reaction (qPCR) protocol targeting geoA sequences that encode a germacradienol synthase involved in geosmin synthesis. New geoA-related sequences were retrieved from eleven geosmin-producing Actinomycete strains, among them two Streptomyces strains isolated from two RAS. Combined with geoA-related sequences available in gene databases, we designed primers and standards suitable for qPCR assays targeting mainly Streptomyces geoA. Using our qPCR protocol, we succeeded in measuring the level of geoA copies in sand filter and biofilters in two RAS. This study is the first to apply qPCR assays to detect and quantify the geosmin synthesis gene (geoA) in RAS. Quantification of geoA in RAS could permit the monitoring of the level of geosmin producers prior to the occurrence of geosmin production. This information will be most valuable for fish producers to manage further development of off-flavour events. PMID:22060964

Auffret, Marc; Pilote, Alexandre; Proulx, Emilie; Proulx, Daniel; Vandenberg, Grant; Villemur, Richard

2011-12-15

357

Wenyingzhuangia marina gen. nov., sp. nov., a member of the family Flavobacteriaceae isolated from a recirculating mariculture system.  

PubMed

A Gram-stain-negative, strictly aerobic and heterotrophic bacterial strain, designed strain D1(T), was isolated from a recirculating mariculture system in Tianjin, China. Its taxonomic position was determined using a polyphasic approach. Cells of strain D1(T) were non-flagellated short rods, 0.3-0.5 µm wide and 0.5-1.0 µm long. Growth was observed at 15-30 °C (optimum, 25 °C), at pH 5.5-9.0 (optimum, pH 6.5-7.0) and in the presence of 1-8% (w/v) NaCl (optimum, 2-3 %). Cells contained carotenoid pigments but not flexirubin-type pigments. Strain D1(T) contained MK-6 as the sole menaquinone and phosphatidylethanolamine (PE) as the sole phospholipid and four unidentified lipids. The major cellular fatty acids (>10%) were iso-C15 : 0 (23.2 %), iso-C17 : 0 3-OH (15.2%), C(16 : 1)?7c/C(16 : 1)?6c (14.3%), iso-C(15 : 0) 3-OH (13.5%) and iso-C15 : 1 G (10.8%). 16S rRNA gene sequence analyses indicated that strain D1(T) belonged to the family Flavobacteriaceae and showed closest phylogenetic relationship to the genus Lutibacter, with highest sequence similarity to Lutibacter aestuarii MA-My1(T) (92.2%). The DNA G+C content of strain D1(T) was 35.9 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain D1(T) was considered to represent a novel species in a new genus of the family Flavobacteriaceae, for which the name Wenyingzhuangia marina gen. nov., sp. nov. is proposed. The type strain of the type species is D1(T) (?=?CGMCC 1.12162(T)?=?JCM 18494(T)). PMID:24096358

Liu, Ying; Liu, Liang-Zi; Liu, Hong-Can; Zhou, Yu-Guang; Qi, Fang-Jun; Liu, Zhi-Pei

2014-02-01

358

Culture of selected organisms in recirculating and flow-through systems using thermal effluent  

E-print Network

''~81) | ' o1 d Atl . t' k !!~g alt )'thdd ("~o lit. )Q t 'pd mullet with croaker, channel catfish (Ictalurus punctatus), spot (Leiostomus xanthurus), Florida pompano (Trachinotus =, 1 ', ) ~ 'Po td t t (C~ h 1 ), hl h d - (P~ o ' ) od o th fl d" (~f1 ' htl... setiferus ~ecealops atlantica ~C' do ~t -* '1' ~lt' L tj d L tl Lobo tes surinamensis Archosargus probatocephalus Pogonias cromis -' 1 ~tl ~ld t 1 o to systems were stocked with 20 oysters and no fish. All oysters were suspend~ d . in 45 x 33 x 10-c...

Berry, Terri Layne

2012-06-07

359

Systems and methods for reactive distillation with recirculation of light components  

DOEpatents

Systems and methods for producing gas-to-liquids products using reactive distillation are provided. The method for producing gas-to-liquids products can include reacting a feedstock in a column having a distillation zone and a reaction zone to provide a bottoms stream and an overhead stream. A first portion of the overhead stream can be recycled to the column at the top of the reaction zone and second portion of the overhead stream can be recycled to the column at the bottom of the reaction zone.

Stickney, Michael J. (Nassau Bay, TX); Jones, Jr., Edward M. (Friendswood, TX)

2011-07-26

360

Phylogenetic diversity of ammonia-oxidizing archaea and bacteria in biofilters of recirculating aquaculture systems.  

PubMed

We constructed ammonia monooxygenase alpha subunit (amoA) gene clone libraries of ammonia-oxidizing archaea (AOA) and bacteria (AOB) from three biofiltration tanks used for closed marine fish culture systems. The number of operational taxonomic units (OTUs) found in any one place was 76%-80% of the total OTUs in each tank for AOA and 100% for AOB when OUTs were defined on the basis of a 5% nucleotide difference. In a phylogenetic tree, all of the AOA amoA sequences fell into a cluster, which contained Candidatus Nitrosopumilus maritimus. All of the AOB amoA sequences were related to the Nitrosospira lineage. These results indicated that different ammonia oxidizers were present in different tanks, but that the dominant phylogenetic types were stable. In a biofiltration tank to which a high concentration of ammonium chloride was added periodically to condition the biofilter materials, most of the AOA amoA sequences were different from the dominant one observed in the fish culture tanks. The AOB amoA sequences were also different, and were similar to those of Nitrosomonas aestuarii. These findings suggest that high concentration ammonia loads have a considerable affect on ammonia-oxidizer community composition. PMID:22897959

Sakami, Tomoko; Andoh, Tadashi; Morita, Tetsuo; Yamamoto, Yoshihisa

2012-09-01

361

Containment system for supercritical water oxidation reactor  

DOEpatents

A system for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary.

Chastagner, Philippe (3134 Natalie Cir., Augusta, GA 30909-2748)

1994-01-01

362

Exhaust gas recirculation system  

SciTech Connect

An EGR assembly is disclosed of a sonic flow EGR valve and a fluid pressure actuated servo operated by air pressure modified by an air bleed device controlled in response to changes in carburetor venturi vacuum levels to provide EGR valve openings in proportion to engine air flow increases.

Rachedi, S.H.

1983-08-16

363

Exhaust gas recirculation system  

Microsoft Academic Search

There is disclosed an EGR assembly of a sonic flow EGR valve and a fluid pressure actuated servo operated by air pressure modified by an air bleed device controlled in response to changes in carburetor venturi vacuum levels to provide EGR valve openings in proportion to engine air flow increases.

Rachedi

1983-01-01

364

Exhaust gas recirculation system  

Microsoft Academic Search

An EGR assembly is disclosed of a sonic flow EGR valve and a fluid pressure actuated servo operated by air pressure modified by an air bleed device controlled in response to changes in carburetor venturi vacuum levels to provide EGR valve openings in proportion to engine air flow increases.

Rachedi

1983-01-01

365

Exhaust gas recirculation system  

Microsoft Academic Search

Passage means are described for communicating an EGR passage between first and second EGR control valves. A vacuum chamber of an actuator of the second EGR control valve is prevented from being clogged by solids of the engine exhaust gases by the provision of an air pump for feeding air to fill the passage means between an orifice therein and

Aoyama

1977-01-01

366

Exhaust gas recirculation system  

SciTech Connect

There is disclosed an EGR assembly of a sonic flow EGR valve and a fluid pressure actuated servo operated by air pressure modified by an air bleed device controlled in response to changes in carburetor venturi vacuum levels to provide EGR valve openings in proportion to engine air flow increases.

Rachedi, S.H.

1983-10-18

367

Residential hot water distribution systems: Roundtablesession  

SciTech Connect

Residential building practice currently ignores the lossesof energy and water caused by the poor design of hot water systems. Theselosses include: combustion and standby losses from water heaters, thewaste of water (and energy) while waiting for hot water to get to thepoint of use; the wasted heat as water cools down in the distributionsystem after a draw; heat losses from recirculation systems and thediscarded warmth of waste water as it runs down the drain. Severaltechnologies are available that save energy (and water) by reducing theselosses or by passively recovering heat from wastewater streams and othersources. Energy savings from some individual technologies are reported tobe as much as 30 percent. Savings calculations of prototype systemsincluding bundles of technologies have been reported above 50 percent.This roundtable session will describe the current practices, summarizethe results of past and ongoing studies, discuss ways to think about hotwater system efficiency, and point to areas of future study. We will alsorecommend further steps to reduce unnecessary losses from hot waterdistribution systems.

Lutz, James D.; Klein, Gary; Springer, David; Howard, Bion D.

2002-08-01

368

Biogeochemical processes in intensive zero-effluent marine fish culture with recirculating aerobic and anaerobic biofilters  

Microsoft Academic Search

The biogeochemical processes that drive nutrient transformations and recycling in organic marine sediment–water environments were studied for 17 months in a zero-effluent intensive recirculating culture system. The system consisted of a 10 m3 gilthead seabream (Sparus aurata) tank coupled to aerobic and anaerobic water treatment elements. Nutrients and alkalinity were measured in the system to quantify the main biogeochemical processes. Fractions of

Amir Neori; Michael D. Krom; Jaap van Rijn

2007-01-01

369

Carburization of steels in a circulatory system using water-gas atmospheres  

Microsoft Academic Search

In order to economize on raw materials for producing controlled atmospheres and to avoid the air pollution caused by exhausted\\u000a atmospheres, the feasibility of carburizing steel by using recirculated water-gas atmospheres was investigated. Water-gas\\u000a was generated in a closed system and an open system respectively, and steel samples were heated under the water-gas atmospheres.\\u000a Based on the heating results of

Y. C. Chen; G. S. Lu

1992-01-01

370

Iodine and selenium supplementation increased survival and changed thyroid hormone status in Senegalese sole (Solea senegalensis) larvae reared in a recirculation system.  

PubMed

To test how iodine and both iodine and selenium supplementation affected the thyroid status as well as growth and survival in Senegalese sole, larvae were reared in a recirculation system from 15 to 34 DAH. Sets of three tanks were assigned to each of the following three diets: control (C), iodine (I) and iodine and selenium (I + Se). Samples were collected at 15, 27 and 34 DAH to determine dry weight, iodine and selenium levels, GPx and ORD activities, thyroid hormone levels and thyroid follicles histology. At 34 DAH, fish from the control (C) treatment suffered from hyperplasia of the thyroid follicles (goitre), whereas iodine-treated larvae did not (I and I + Se). Lower survival rates in the C groups were probably a consequence of the hyperplasia. Moreover, there was an improvement in thyroid hormone status in I- and I + Se-treated larvae, showing that further supplementation of live feed with iodine can be crucial for fish at early life stages, as it seems to sustain normal larval development, when reared in a recirculation system. Selenium did not affect the results. Together with previous results, this indicates selenium supplement is more important at younger life stages. PMID:21932022

Ribeiro, A R A; Ribeiro, L; Sæle, O; Dinis, M T; Moren, M

2012-06-01

371

Intermediate water recovery system  

NASA Technical Reports Server (NTRS)

A water recovery system for collecting, storing, and processing urine, wash water, and humidity condensates from a crew of three aboard a spacecraft is described. The results of a 30-day test performed on a breadboard system are presented. The intermediate water recovery system produced clear, sterile, water with a 96.4 percent recovery rate from the processed urine. Recommendations for improving the system are included.

Deckman, G.; Anderson, A. R. (editor)

1973-01-01

372

Small recirculating filters for nitrogen reduction.  

PubMed

Concerned about the negative impacts of nitrogen loading from septic systems on the Chesapeake Bay watershed, Maryland's Anne Arundel County Health Department has pioneered the use of small recirculating sand filters to reduce nitrogen in effluent from residential septic systems. Recirculating sand filters can reduce the total nitrogen in septic-tank effluent by up to 70 percent. Years of experience and the county's participation in the National Onsite Demonstration Project have led to modifications that make the filters more acceptable to homeowners. Use of alternative media, changes in flow patterns, and homeowner education have increased acceptance by homeowners. PMID:11544843

Piluk, R J; Byers, B R

2001-09-01

373

Effect of Water pH on Yield and Nutritional Status of Greenhouse Cucumber Grown in Recirculating Hydroponics  

Microsoft Academic Search

Cucumbers are produced in integrated hydroponic and aquaculture systems (aquaponics). Aquaponics balances pH for plants, fish, and nitrifying bacteria. Nitrification prevents buildup of toxic waste ammonia by conversion to nitrate (NO3 - nitrogen (N). The pH for hydroponic cucumbers (5.5–6.0) and nitrification (7.5–9.0) requires reconciliation to improve systems integration. Cucumbers were grown at pH of 5.0, 6.0, 7.0, and 8.0

R. V. Tyson; E. H. Simonne; D. D. Treadwell; M. Davis; J. M. White

2008-01-01

374

Economic values of growth and feed efficiency for fish farming in recirculating aquaculture system with density and nitrogen output limitations: a case study with African catfish (Clarias gariepinus).  

PubMed

In fish farming, economic values (EV) of breeding goal traits are lacking, even though they are key parameters when defining selection objectives. The aim of this study was to develop a bioeconomic model to estimate EV of 2 traits representing production performances in fish farming: the thermal growth coefficient (TGC) and the feed conversion ratio (FCR). This approach was applied to a farm producing African catfish (Clarias gariepinus) in a recirculating aquaculture system (RAS). In the RAS, 2 factors could limit production level: the nitrogen treatment capacity of the biofilter or the fish density in rearing tanks at harvest. Profit calculation includes revenue from fish sales, cost of juveniles, cost of feed, cost of waste water treatment, and fixed costs. In the reference scenario, profit was modeled to zero. EV were calculated as the difference in profit per kilogram of fish between the current population mean for both traits (µt) and the next generation of selective breeding (µt + ?t) for either TGC or FCR. EV of TGC and FCR were calculated for three generations of hypothetical selection on either TGC or FCR (respectively 6.8% and 7.6% improvement per generation). The results show that changes in TGC and FCR can affect both the number of fish that can be stocked (number of batches per year and number of fish per batch) and the factor limiting production. The EV of TGC and FCR vary and depend on the limiting factors. When dissolved NH3-N is the limiting factor for both µt and µt + ?t, increasing TGC decreases the number of fish that can be stocked but increases the number of batches that can be grown. As a result, profit remains constant and EVTGC is zero. Increasing FCR, however, increases the number of fish stocked and the ratio of fish produced per kilogram of feed consumed ("economic efficiency"). The EVFCR is 0.14 €/kg of fish, and profit per kilogram of fish increases by about 10%. When density is the limiting factor for both µt and µt + ?t, the number of fish stocked per batch is fixed; therefore, extra profit is obtained by increasing either TGC, which increases the annual number of batches, or by decreasing FCR, which decreases annual feed consumption. EVTGC is 0.03 €/kg of fish and EVFCR is 0.05-0.06 €/kg of fish. These results emphasize the importance of calculating economic values in the right context to develop efficient future breeding programs in aquaculture. PMID:25414104

Besson, M; Komen, H; Aubin, J; de Boer, I J M; Poelman, M; Quillet, E; Vancoillie, C; Vandeputte, M; van Arendonk, J A M

2014-12-01

375

Exhaust gas recirculation for an internal combustion engine  

Microsoft Academic Search

A back pressure control type EGR system is disclosed wherein a vacuum line for connecting an EGR port with a vacuum operated EGR valve for controlling the amount of the recirculated exhaust gas is selectively opened to an air chamber of a vacuum modulator valve responsive to the pressure of the recirculated exhaust gas. The air chamber is connected, via

H. Onaka; Y. Sato

1980-01-01

376

Engineering development for a small-scale recirculator experiment  

SciTech Connect

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.

Newton, M.A.; Deadrick, F.J.; Hanks, R.L.; Hawkins, S.A.; Holm, K.A.; Kirbie, H.C.; Karpenko, V.P.; Nattrass, L.A. [Lawrence Livermore National Lab., CA (United States); Longinotti, D.B. [EG and G Energy Measurements, Inc., Pleasanton, CA (United States)

1995-09-04

377

Cooling Water Systems Module  

NSDL National Science Digital Library

The Center for the Advancement of Process Technology presents this free sample module on cooling water systems in the process industry. The material includes 21 slides and will help learners understand related terms, the purpose of the basic equipment involved in cooling water systems and the safety, health and environmental concerns involved with these systems.

2013-01-04

378

Water Purification Systems  

NASA Technical Reports Server (NTRS)

A water purification/recycling system developed by Photo-Catalytics, Inc. (PCI) for NASA is commercially available. The system cleanses and recycles water, using a "photo-catalysis" process in which light or radiant energy sparks a chemical reaction. Chemically stable semiconductor powders are added to organically polluted water. The powder absorbs ultraviolet light, and pollutants are oxidized and converted to carbon dioxide. Potential markets for the system include research and pharmaceutical manufacturing applications, as well as microchip manufacture and wastewater cleansing.

1992-01-01

379

Options for transpiration water removal in a crop growth system under zero gravity conditions  

NASA Technical Reports Server (NTRS)

The operation of a microgravity crop-growth system is a critical feature of NASA's Closed Ecological Life Support System (CELSS) development program. Transpiration-evolved water must be removed from the air that is recirculated in such a system, perhaps supplying potable water in the process. The present consideration of candidate systems for CELSS water removal gives attention to energy considerations and to a mechanical, inertial-operation water-separation system that was chosen due to the depth of current understanding of its operation.

Blackwell, C. C.; Kliss, M.; Yendler, B.; Borchers, B.; Yendler, Boris S.; Nguyen, Thoi K.; Waleh, Ahmad

1991-01-01

380

National Water Trails System  

NSDL National Science Digital Library

Some might wonder: What exactly is the National Water Trails System (NWTS)? That's a good question; NWTS describes the system as "a distinctive national network of exemplary water trails that are cooperatively supported and sustained." This website provides information about the NWTS for policy makers, water enthusiasts, and other interested parties. Casual visitors will want to start with the Explore a National Water Trail area. Here they can use an interactive map to locate water trails, and go deeper into each riverine passage with the Stories and Images section. Moving on, policy makers and park administrators will want to peruse the Develop and Manage a National Water Trail area. This section contains some basic answers to queries such s "What Are The Benefits of National Water Trail Designation?" and "How Do I Apply For National Water Trail Designation?"

381

Exhaust gas recirculator  

SciTech Connect

An exhaust gas recirculator for an internal combustion engine having an exhaust pipe, an intake manifold and a carburetor throttle valve. The exhaust gas recirculator comprises an egr passage which makes the exhaust pipe communicate with the intake manifold, an egr controlling valve and an egr valve respectively arranged in the upper and lower portions of the egr passage. The egr valve operates in association with the carburetor throttle valve for metering the flow of egr gas. The egr controlling valve is separated by a diaphragm into an egr gas chamber communicating with the egr passage between the egr controlling valve and the egr valve and a negative pressure chamber communicating with the intake manifold. The negative pressure chamber contains a compression spring, and the diaphragm is connected with a valve member through a rod upon which is disposed a stopper to serve as a different seal in place of the valve member to close off the exhaust gas passage, which valve member and stopper are constructed to be opened and closed by pressure difference between the egr gas chamber and the negative pressure chamber and by elastic force of the compression spring. The egr controlling valve functions to control the pressure difference around the egr valve to be constant.

Suda, K.

1983-01-04

382

Reactor water cleanup system  

DOEpatents

A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling. 1 figure.

Gluntz, D.M.; Taft, W.E.

1994-12-20

383

Reactor water cleanup system  

DOEpatents

A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling.

Gluntz, Douglas M. (San Jose, CA); Taft, William E. (Los Gatos, CA)

1994-01-01

384

Purge water management system  

DOEpatents

A purge water management system is described for effectively eliminating the production of purge water when obtaining a groundwater sample from a monitoring well. In its preferred embodiment, the purge water management system comprises an expandable container, a transportation system, and a return system. The purge water management system is connected to a wellhead sampling configuration, typically permanently installed at the well site. A pump, positioned with the monitoring well, pumps groundwater through the transportation system into the expandable container, which expands in direct proportion with volume of groundwater introduced, usually three or four well volumes, yet prevents the groundwater from coming into contact with the oxygen in the air. After this quantity of groundwater has been removed from the well, a sample is taken from a sampling port, after which the groundwater in the expandable container can be returned to the monitoring well through the return system. The purge water management system prevents the purge water from coming in contact with the outside environment, especially oxygen, which might cause the constituents of the groundwater to oxidize. Therefore, by introducing the purge water back into the monitoring well, the necessity of dealing with the purge water as a hazardous waste under the Resource Conservation and Recovery Act is eliminated.

Cardoso-Neto, J.E.; Williams, D.W.

1995-01-01

385

Airlift recirculation well test results -- Southern sector  

SciTech Connect

Chlorinated solvents used in the A and M-Areas at the Savannah River Site (SRS) from 1952--1982 have contaminated the groundwater under the site. A plume of groundwater contaminated with trichloroethylene (TCE) and perchloroethylene (PCE) in the Lost Lake aquifer is moving generally southward with the natural flow of groundwater. To comply with the requirements of the current SCDHEC Part B Permit, a series of wells is being installed to contain and treat the plume. Airlift Recirculation Wells (ARW) are a new and innovative technology with potential for more cost effective implementation than conventional pump and treat systems. Two Airlift Recirculation Wells have been installed and tested to quantify performance parameters needed to locate a line of these wells along the leading edge of the contaminant plume. The wells proved to be very sensitive to proper development, but after this requirement was met, performance was very good. The Zone of Capture has been estimated to be within a radius of 130--160 ft. around the wells. Thus a line of wells spaced at 250 ft. intervals could intercept the contaminant plume. At SSR-012, TCE was stripped from the groundwater at approximately 1.2 lb./day. The longer term effect of the recirculation wells upon the plume and the degree of recirculation within the aquifer itself will require additional data over a longer time period for an accurate review. Data collection is ongoing.

White, R.M.; Hiergesell, R.A.

1997-08-01

386

Exhaust gas recirculation apparatus for an internal combustion engine  

SciTech Connect

Disclosed herein is an internal combustion engine provided with an exhaust gas recirculation system of so-called back pressure control type. The exhaust gas recirculation system is provided with a vacuum line connecting a so-called EGR port with a vacuum operated flow control valve, and a modulator valve having a control chamber selectively opened to the vacuum line in response to the pressure of recirculated exhaust gas for controlling vacuum signal level of the flow control valve. The control chamber of the modulator is connected to another vacuum signal port located slightly above the EGR port.

Abe, T.; Hasegawa, Y.; Kawai, N.; Ota, I.; Yamamoto, H.; Yamasaki, T.

1980-09-16

387

Cooling Water System Optimization  

E-print Network

During summer months, many manufacturing plants have to cut back in rates because the cooling water system is not providing sufficient cooling to support higher production rates. There are many low/no-cost techniques available to improve tower...

Aegerter, R.

2005-01-01

388

Design study of a gas turbine combustor with heat recirculation  

NASA Technical Reports Server (NTRS)

A means of avoiding stoichiometric combustion, reducing emissions, and yet providing stable burning for lean mixtures is based on the use of heat recirculation rather than flow recirculation. This paper is concerned with the calculations of the design parameters of a gas turbine combustor with heat exchanger to produce the desired preheat temperature. The combustor inlet temperature, maximum temperature, equivalence ratio and recirculated heat are determined by thermodynamic analysis. The heat transfer analysis then provides the dimensions of the system to produce the predetermined boundary conditions. It is indicated that practical combustor design may be feasible for reactant mixtures as low as equivalence ratio 0.2.

Ganji, A.; Branch, M. C.; Oppenheim, A. K.

1976-01-01

389

Automatic hot water recovery system  

Microsoft Academic Search

Heat in the hot water lines of a water system is automatically recovered by providing a bridge conduit between the cold water lines and the hot water lines and by depressurizing the hot water lines relative to the cold water lines thereby to automatically direct higher pressure cold water into the hot water lines through the interconnection, which preferably is

Haws

1982-01-01

390

Recirculation of municipal landfill leachate  

E-print Network

aerobic decomposition of the leachate on the surface in addition to the anaer obic decomposition of the leachate within the landfill and the increased efficiency due to recirculation. HETHODS Each of the experimental landfi 1 1 cel is, as constructed... aerobic decomposition of the leachate on the surface in addition to the anaer obic decomposition of the leachate within the landfill and the increased efficiency due to recirculation. HETHODS Each of the experimental landfi 1 1 cel is, as constructed...

Pinkowski, Brian Jude

2012-06-07

391

Application of chemical coagulation aids for the removal of suspended solids (TSS) and phosphorus from the microscreen effluent discharge of an intensive recirculating aquaculture system  

USGS Publications Warehouse

An evaluation of two commonly used coagulation-flocculation aids (alum and ferric chloride) was conducted to determine optimum conditions for treating the backwash effluent from microscreen filters in an intensive recirculating aquaculture system. Tests were carried out to evaluate the dosages and conditions (mixing and flocculation stirring speeds, durations, and settling times) required to achieve optimum waste capture. The orthophosphate removal efficiency for alum and ferric chloride were greater than 90% at a dosage of 60 mg/L. Optimum turbidity removal was achieved with a 60-mg/L dosage for both alum and ferric chloride. Both alum and ferric chloride demonstrated excellent removal of suspended solids from initial total suspended solid values of approximately 320 mg/L to approximately 10 mg/L at a dosage of 60 mg/L. Flocculation and mixing speed and duration played only a minor role in the removal efficiencies for both orthophosphates and suspended solids. Both coagulation-flocculation aids also exhibited excellent settling characteristics, with the majority of the floc quickly settling out in the first 5 min.

Ebeling, J. M.; Ogden, S. R.; Sibrell, P. L.; Rishel, K. L.

2004-01-01

392

Effects of spectral composition, photoperiod and light intensity on the gonadal development of Atlantic salmon Salmo salar in recirculating aquaculture systems (RAS)  

NASA Astrophysics Data System (ADS)

Artificial lighting regimes have been successfully used to inhibit sexual maturity of Atlantic salmon in confinement. However, when these operations are applied in commercial recirculating aquaculture systems (RAS) using standard lighting technology, sexual maturation is not suppressed. In this study, an L9 (33) orthogonal design was used to determine the effects of three factors (spectral composition, photoperiod, and light intensity) on the gonadal development of Atlantic salmon in RAS. We demonstrated that the photoperiod at the tested levels had a much greater effect on the gonadosomatic index and female Fulton condition factor than spectral composition and light intensity. The photoperiod had a significant effect on the secretion of sex steroids and melatonin (P<0.05), and a short photoperiod delayed sex steroid and melatonin level increases. The three test factors had no significant effects on the survival rate, specific growth rate, relative weight gain, and male Fulton condition factor (P>0.05). The optimum lighting levels in female and male Atlantic salmon were LD 8:16, 455 nm (or 625 nm), 8.60 W/m2; and LD 8:16, 8.60 W/m2, 455 nm respectively. These conditions not only delayed gonadal development, but also had no negative effects on Atlantic salmon growth in RAS. These results demonstrate that a combination of spectral composition, photoperiod and light intensity is effective at delaying the gonadal development of both male and female salmon in RAS.

Qiu, Denggao; Xu, Shihong; Song, Changbin; Chi, Liang; Li, Xian; Sun, Guoxiang; Liu, Baoliang; Liu, Ying

2014-10-01

393

Heat recirculating cooler for fluid stream pollutant removal  

DOEpatents

A process by which heat is removed from a reactant fluid to reach the operating temperature of a known pollutant removal method and said heat is recirculated to raise the temperature of the product fluid. The process can be utilized whenever an intermediate step reaction requires a lower reaction temperature than the prior and next steps. The benefits of a heat-recirculating cooler include the ability to use known pollutant removal methods and increased thermal efficiency of the system.

Richards, George A. (Morgantown, WV); Berry, David A. (Morgantown, WV)

2008-10-28

394

Automatic hot water recovery system  

Microsoft Academic Search

A heat recovery system recovers hot water to an insulated tank through reciprocally variable volume chambers which are biased to draw water from hot water lines when the pressure throughout the system is equalized. One-way valving means permits continuous water flow when desired through the hot water tank to the hot water outlet. In a specific embodiment, bias is effected

Haws

1985-01-01

395

Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia  

NASA Technical Reports Server (NTRS)

A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

1981-01-01

396

Dynamics of microorganism populations in recirculating nutrient solutions  

NASA Technical Reports Server (NTRS)

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.

Strayer, R. F.

1994-01-01

397

Automatic hot water recovery system  

SciTech Connect

Heat in the hot water lines of a water system is automatically recovered by providing a bridge conduit between the cold water lines and the hot water lines and by depressurizing the hot water lines relative to the cold water lines thereby to automatically direct higher pressure cold water into the hot water lines through the interconnection, which preferably is located near the hot water outlet. The higher pressure cold water forces the hot water back into the storage tank and out of the hot water lines until pressure is equalized. Loss of unused heat trapped in the hot water lines is minimized thereby saving energy.

Haws, S.K.

1982-03-30

398

Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling Systems for the Advanced Extravehicular Mobility Unit Portable Life Support System  

NASA Technical Reports Server (NTRS)

Spacesuit Water Membrane Evaporator - Baseline heat rejection technology for the Portable Life Support System of the Advanced EMU center dot Replaces sublimator in the current EMU center dot Contamination insensitive center dot Can work with Lithium Chloride Absorber Radiator in Spacesuit Evaporator Absorber Radiator (SEAR) to reject heat and reuse evaporated water The Spacesuit Water Membrane Evaporator (SWME) is being developed to replace the sublimator for future generation spacesuits. Water in LCVG absorbs body heat while circulating center dot Warm water pumped through SWME center dot SWME evaporates water vapor, while maintaining liquid water - Cools water center dot Cooled water is then recirculated through LCVG. center dot LCVG water lost due to evaporation (cooling) is replaced from feedwater The Independent TCV Manifold reduces design complexity and manufacturing difficulty of the SWME End Cap. center dot The offset motor for the new BPV reduces the volume profile of the SWME by laying the motor flat on the End Cap alongside the TCV.

Bue, Grant C.; Makinen, Janice V.; Miller, Sean.; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Petty, Brian

2014-01-01

399

Control system for internal combustion engines, provided with an exhaust gas recirculation control having a fail safe function  

SciTech Connect

A control system for internal combustion engines, which comprises: a power transistor connected to the solenoid of a solenoid valve forming an egr control valve for energization of the same; an abnormality detecting circuit arranged for comparing the input and output levels of the power transistor to generate an output signal when the two levels are out of an inverted relationship; a timer arranged for generating an output signal when the output signal of the abnormality detecting circuit is continuously generated over a predetermined period of time; and emergency means actuatable by the output signal of the timer. The emergency means may include an alarm device and a safety circuit, both responsive to the output of the timer to give the alarm and render the power transistor inoperative, respectively.

Hasegawa, S.; Narasaka, S.; Otsuka, K.

1983-03-08

400

Remote water monitoring system  

NASA Technical Reports Server (NTRS)

A remote water monitoring system is described that integrates the functions of sampling, sample preservation, sample analysis, data transmission and remote operation. The system employs a floating buoy carrying an antenna connected by lines to one or more sampling units containing several sample chambers. Receipt of a command signal actuates a solenoid to open an intake valve outward from the sampling unit and communicates the water sample to an identifiable sample chamber. Such response to each signal receipt is repeated until all sample chambers are filled in a sample unit. Each sample taken is analyzed by an electrochemical sensor for a specific property and the data obtained is transmitted to a remote sending and receiving station. Thereafter, the samples remain isolated in the sample chambers until the sampling unit is recovered and the samples removed for further laboratory analysis.

Grana, D. C.; Haynes, D. P. (inventors)

1978-01-01

401

Dynamics of microorganism populations in recirculating nutrient solutions  

NASA Technical Reports Server (NTRS)

This overview covers the basic microbial ecology of recirculating hydroponic solutions. Examples from NASA and Soviet 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.

Strayer, R. F.

1994-01-01

402

Automatic hot water recovery system  

SciTech Connect

A heat recovery system recovers hot water to an insulated tank through reciprocally variable volume chambers which are biased to draw water from hot water lines when the pressure throughout the system is equalized. One-way valving means permits continuous water flow when desired through the hot water tank to the hot water outlet. In a specific embodiment, bias is effected by a piston having opposing faces of unequal area forming reciprocally moving walls of the chambers.

Haws, S. K.

1985-05-21

403

Blood cytokine, chemokine and gene expression in cholestasis patients with intractable pruritus treated with a molecular adsorbent recirculating system: A case series  

PubMed Central

BACKGROUND: The molecular adsorbent recirculating system (MARS) is an albumin-dialysis modality that has been investigated predominantly in patients with acute and acute-on-chronic liver failure. OBJECTIVES: To report the clinical efficacy and safety of MARS therapy for intractable pruritus in cholestasis patients with stable chronic liver disease, characterizing the impact of MARS on cytokine levels and on the transcriptome in the blood compartment. METHODS: MARS therapy was performed on three patients with cholestatic liver disease using 8 h runs for two consecutive days. The expression levels of 65 cytokines/chemokines and 24,000 genes were profiled by Luminex (Luminex Corporation, USA) and microarray, respectively. RESULTS: A quality-of-life assessment demonstrated a marked improvement during therapy, which was sustained in two of three patients. No bleeding or infectious complications were observed. Bile acid levels were markedly reduced following MARS (mean [± SD] pretreatment 478.9±112.2 ?mol/L versus post-treatment 89.7±68.8 ?mol/L). Concordant decreases in cytokine/chemokine levels were noted for interleukin (IL)-1beta, IL-2, IL-6, IL-8, IL-12 (p40), RANTES, tranforming growth factor-alpha, tumour necrosis factor-alpha and thrombopoietin following MARS. On microarray profiling, biologically relevant concordant changes among all patients were evident for 20 different genes (10 upregulated and 10 downregulated). The upregulation of several potentially immune suppressive/regulatory genes (eg, early growth response 3 [EGR-3], ephrin-A2 [EFNA2] and serum amyloid A1 [SAA1]), concurrent with downregulation of genes involved in innate immunity (eg, toll-like receptor 4 interactor with leucine-rich repeats [TRIL]) and inflammation (eg, ephrin receptor B1 [EPHB1]), was observed. CONCLUSIONS: This investigative approach offers new insights into intractable pruritus and suggests future therapeutic targets. The clinical benefit of MARS in cholestasis patients with intractable pruritus may not exclusively result from filtration of pruritogens, but also from systemic changes in cytokine/chemokine levels and changes in gene expression of blood cells. PMID:23166903

Lisboa, Luiz F; Asthana, Sonal; Kremer, Andreas E; Swain, Mark; Bagshaw, Sean M; Gibney, Noel; Karvellas, Constantine J

2012-01-01

404

Optimization of Chilled Water Systems  

E-print Network

Chilled water systems are one of the major energy consumers in industrial, commercial, and institutional complexes. The centralization of chilled water systems has considerable advantages, namely: simplified controls, the installed capacity...

Gidwani, B. N.

1984-01-01

405

Optimization of Chilled Water Systems  

E-print Network

OPTIMIZATION OF CHILLED WATER SYSTEMS B. N. GIDWANI, P.E., Vice President? Roy F. Weston, Inc.?West Chester, Pennsylvania 19380 ABSTRACT Chilled water systems are one of the major energy consumers in industrial, commercial, and institutional... complexes. The centralization of chilled water systems presents numerous advantages, including simplified controls, reduced installation capacity due to diversity, and consolidated maintenance and operation. Centrally chilled water systems present...

Gidwani, B. N.

406

Water-quality changes during the conditioning of small, closed seawater systems  

SciTech Connect

Mineralization and nitrification processes were monitored during the conditioning period of replicate recirculating seawater systems A and B. High-quality water was achieved by a combination of bacteriological and mechanical filtration, activated charcoal adsorption, foam separation and uv sterilization. These two systems were conditioned over a 12-week period using penaeus merguiensis as conditioning animals. Detritus from fecal matter and food increased ammonia levels immediately. At two weeks, nitrite levels increased and ammonia fell. Nitrite levels remained high until week 8 in system A and week 10 in system B. (Copyright (c) CSIRO Australia 1986. Printed by CSIRO, Melbourne.)

Heales, D.S.

1985-01-01

407

Recirculating Heavy Ion Accelerator Experiment  

Microsoft Academic Search

Because of their high efficiency, high repetition rate, and relatively simple target chamber geometry, heavy-ion accelerators are attractive candidates as drivers for inertial fusion power plants. Recirculating induction accelerators have been proposed as potential lower cost alternatives to linear induction machines. The requirement of coordinated and accelerated bending introduces new challenges. A program to develop a small (2.2m radius) scaled

A. Molvik; J. J. Barnard; M. D. Cable; D. A. Callahan; V. Cianciolo; A. Friedman; D. P. Grote; G. W. Kamin; H. C. Kirbie; B. G. Logan; S. M. Lund; L. A. Nattrass; M. B. Nelson; T. C. Sangster; W. M. Sharp; C. Ward; T. J. Fessenden; D. L. Judd; H. S. Hopkins; A. G. Debeling; D. B. Longinotti

1996-01-01

408

Nitrification in Drinking Water Systems  

Microsoft Academic Search

Nitrification is increasingly a concern in United States potable water distribution systems. This paper reviews research on nitrification as it relates to the ammonia levels and unique environments present in potable water distribution systems. Factors affecting nitrification occurrence, nitrification impacts on water quality and corrosion, and nitrification monitoring and control methods are emphasized. The potential role of nitrogen cycling via

Yan Zhang; Nancy Love; Marc Edwards

2009-01-01

409

Liquid hydrogen and liquid oxygen feedline passive recirculation analysis  

Microsoft Academic Search

During the National Launch System design phase, a computer code (FEEDLINE) was written to analyze the feasibility of using passive recirculation propellant conditioning for the LH2 and LO2 feed systems. The FEEDLINE code was employed to provide temperature profiles to the STME design team. The team used the temperature profiles to determine if the required Space Transportation Main Engine net

Kimberly A. Holt; Nicole L. Cleary; Andrew J. Nichols; Gretchen L. E. Perry

1993-01-01

410

Experimental Study of the Circulation Air Volume of Recirculation Evaporative Cooling  

E-print Network

This paper introduces the technology of re-circulation evaporative cooling (REC), which uses a portion of supply air as secondary air to make cool water used to indirectly cool outside air through a heat exchanger. The circulation volume...

Xiong, J.; Liu, Z.; Wang, C.; Chen, G.

2006-01-01

411

Investigation of sludge re-circulating clarifiers design and optimization through numerical simulation.  

PubMed

In steam thermal power plants (TPP) with open re-circulating wet cooling towers, elimination of water hardness and suspended solids (SS) is performed in clarifiers. Most of these clarifiers are of high efficiency sludge re-circulating type (SRC) with capacity between 500-1,500 m3/hr. Improper design and/or mal-operation of clarifiers in TPPs results in working conditions below design capacity or production of soft water with improper quality (hardness and S.S.). This causes accumulation of deposits in heat exchangers, condenser tubes, cooling and service water pipes and boiler tubes as well as increasing the ionic load of water at the demineralizing system inlet. It also increases the amount of chemical consumptions and produces more liquid and solid waste. In this regard, a software program for optimal design and simulation of SRCs has been developed. Then design parameters of existing SRCs in four TPPs in Iran were used as inputs to developed software program and resulting technical specifications were compared with existing ones. In some cases improper design was the main cause of poor outlet water quality. In order to achieve proper efficiency, further investigations were made to obtain control parameters as well as design parameters for both mal-designed and/or mal-operated SRCs. PMID:14753549

Davari, S; Lichayee, M J

2003-01-01

412

Exhaust gas recirculation for an internal combustion engine  

SciTech Connect

A back pressure control type EGR system is disclosed wherein a vacuum line for connecting an EGR port with a vacuum operated EGR valve for controlling the amount of the recirculated exhaust gas is selectively opened to an air chamber of a vacuum modulator valve responsive to the pressure of the recirculated exhaust gas. The air chamber is connected, via a vacuum line, to a second vacuum port located slightly above the EGR port. A vacuum switching valve responsive to vacuum pressure at a third port formed in an intake manifold is arranged in the vacuum line.

Onaka, H.; Sato, Y.

1980-06-10

413

Field evaluation of a horizontal well recirculation system for groundwater treatment: Field demonstration at X-701B Portsmouth Gaseous Diffusion Plant, Piketon, Ohio  

SciTech Connect

This report describes the field-scale demonstration performed as part of the project, In Situ Treatment of Mixed Contaminants in Groundwater. This project was a 3{1/2} year effort comprised of laboratory work performed at Oak Ridge National Laboratory and fieldwork performed at the US Department of Energy (DOE) Portsmouth Gaseous Diffusion Plant (PORTS). The overall goal of the project was to evaluate in situ treatment of groundwater using horizontal recirculation coupled with treatment modules. Specifically, horizontal recirculation was tested because of its application to thin, interbedded aquifer zones. Mixed contaminants were targeted because of their prominence at DOE sites and because they cannot be treated with conventional methods. The project involved several research elements, including treatment process evaluation, hydrodynamic flow and transport modeling, pilot testing at an uncontaminated site, and full-scale testing at a contaminated site. This report presents the results of the work at the contaminated site, X-701B at PORTS. Groundwater contamination at X-701B consists of trichloroethene (TCE) (concentrations up to 1800 mg/L) and technetium-998 (Tc{sup 99}) (activities up to 926 pCi/L).

Korte, N.; Muck, M.; Kearl, P.; Siegrist, R.; Schlosser, R.; Zutman, J. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); Houk, T. [Lockheed Martin Energy Systems, Piketon, OH (United States). Portsmouth Gaseous Diffusion Plant] [Lockheed Martin Energy Systems, Piketon, OH (United States). Portsmouth Gaseous Diffusion Plant

1998-08-01

414

Fant's Grove Water System Clemson, SC  

E-print Network

in this report labeled Duke Power Water System Water Quality Table. Water Source The Fant's Grove Water System1 Fant's Grove Water System Clemson, SC 2001 Annual Water-Quality Report Clemson University water. We test our water using sophisticated equipment and advanced procedures. The water supplied

Duchowski, Andrew T.

415

Waste heat utilization system  

Microsoft Academic Search

Power generating plants discharge steam or hot water typically from a steam turbine to a condenser system for the purpose of cooling the discharged fluid prior to its being recirculated. The condenser system receives water from an ambient source pumped using a circulating water pump, said water being elevated to a temperature on the order of 115 to 125°F upon

Timmerman

1979-01-01

416

Waste heat utilization system  

Microsoft Academic Search

Power generating plants discharge steam or hot water typically from a steam turbine to a condenser system for the purpose of cooling the discharged fluid prior to its being recirculated. The condenser system receives water from an ambient source pumped using a circulating water pump, said water being elevated to a temperature on the order of 115 to 125°F upon

Timmerman

1981-01-01

417

Exhaust gas recirculation apparatus for an internal combustion engine  

Microsoft Academic Search

An exhaust gas recirculation apparatus for an internal combustion engine is described that is provided with a vacuum-operated EGR valve having a diaphragm which forms a vacuum control chamber on one side of the diaphragm, which chamber is connected to a vacuum port formed in the engine intake system for transmitting a vacuum signal to the chamber in order to

1978-01-01

418

The recirculation dynamics of bluff body stabilized premixed combustion  

Microsoft Academic Search

Bluff body stabilized premixed combustion is present in many power generation and propulsion systems such as gas turbines and afterburners. In this environment, flow recirculation behind the bluff body provides low speed, hot products that act as an ignition source for the incoming reactants and help anchor the flame. Beyond this coarse phenomenological description, however, understanding of bluff body flame

Marios Soteriou

2005-01-01

419

In Situ Biotreatment of TBA with Recirculation/Oxygenation  

PubMed Central

The potential for in situ biodegradation of tert-butyl alcohol (TBA) by creation of aerobic conditions in the subsurface with recirculating well pairs was investigated in two field studies conducted at Vandenberg Air Force Base (VAFB). In the first experiment, a single recirculating well pair with bromide tracer and oxygen amendment successfully delivered oxygen to the subsurface for 42 days. TBA concentrations were reduced from approximately 500 ?g/L to below the detection limit within the treatment zone and the treated water was detected in a monitoring transect several meters downgradient. In the second experiment, a site-calibrated model was used to design a double recirculating well pair with oxygen amendment, which successfully delivered oxygen to the subsurface for 291 days and also decreased TBA concentrations to below the detection limit. Methylibium petroleiphilum strain PM1, a known TBA-degrading bacterium, was detectable at the study site but addition of oxygen had little impact on the already low baseline population densities, suggesting that there was not enough carbon within the groundwater plume to support significant new growth in the PM1 population. Given favorable hydrogeologic and geochemical conditions, the use of recirculating well pairs to introduce dissolved oxygen into the subsurface is a viable method to stimulate in situ biodegradation of TBA or other aerobically-degradable aquifer contaminants. PMID:23358537

North, Katharine P.; Mackay, Douglas M.; Kayne, Julian S.; Petersen, Daniel; Rasa, Ehsan; Rastegarzadeh, Laleh; Holland, Reef B.; Scow, Kate M.

2012-01-01

420

Mass balance of pharmaceutical and personal care products in a pilot-scale single-sludge system: influence of T, SRT and recirculation ratio.  

PubMed

The influence of operation condition on the fate of 16 pharmaceutical and personal care products (PPCPs) in a single-sludge nitrifying/denitrifying pilot plant was assessed. Volatilisation, sorption and degradation were included in the mass balances to determine the most relevant removal mechanisms during PPCP treatment. Sludge retention time (SRT) was an important factor for the removal of compounds that significantly sorb onto sludge, as ethinylestradiol, whose removal increased 11% when working at SRT above 20 d. The internal recirculation ratio was significant for the removal of moderately biodegradable compounds, as citalopram. The positive effect of operating at warmer temperatures was particularly significant for two antibiotics, implying a 30% increase in their transformations. In the case of naproxen, an influence of sludge acclimation and concentration was observed, leading to removal efficiencies from 27% to 99%. Concerning removal mechanisms, most compounds were removed due to biotransformation, although for fragrances sorption and volatilisation played a role. PMID:22732303

Suárez, Sonia; Reif, Rubén; Lema, Juan M; Omil, Francisco

2012-09-01

421

Outdoor Laboratory Water System Clemson, SC  

E-print Network

in this report labeled Duke Power Water System Water Quality Table. Water Source The Outdoor Laboratory Water = Nephelometric Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL1 Outdoor Laboratory Water System Clemson, SC 1999 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

422

Outdoor Laboratory Water System Clemson, SC  

E-print Network

in this report labeled Duke Power Water System Water Quality Table. Water Source The Outdoor Laboratory Water = Nephelometric Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL1 Outdoor Laboratory Water System Clemson, SC 2000 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

423

Evaluation of three types of structured floating plastic media in moving bed biofilters for total ammonia nitrogen removal in a low salinity hatchery recirculating aquaculture system  

Microsoft Academic Search

Three different commercially available structural plastic media were evaluated in triplicate in moving bed biofilters under low salinity (11–12 ppt) warm water culture conditions and two different feed loading rates. The culture system consisted of nine separate modules that include a double drain fish culture tank paired to a moving bed biofilter. The biofilters were filled with 0.11m3 of one

Timothy J. Pfeiffer; Paul S. Wills

2011-01-01

424

Operational Management System for Regulated Water Systems  

NASA Astrophysics Data System (ADS)

Most of the Dutch large rivers, canals and lakes are controlled by the Dutch water authorities. The main reasons concern safety, navigation and fresh water supply. Historically the separate water bodies have been controlled locally. For optimizating management of these water systems an integrated approach was required. Presented is a platform which integrates data from all control objects for monitoring and control purposes. The Operational Management System for Regulated Water Systems (IWP) is an implementation of Delft-FEWS which supports operational control of water systems and actively gives advice. One of the main characteristics of IWP is that is real-time collects, transforms and presents different types of data, which all add to the operational water management. Next to that, hydrodynamic models and intelligent decision support tools are added to support the water managers during their daily control activities. An important advantage of IWP is that it uses the Delft-FEWS framework, therefore processes like central data collection, transformations, data processing and presentation are simply configured. At all control locations the same information is readily available. The operational water management itself gains from this information, but it can also contribute to cost efficiency (no unnecessary pumping), better use of available storage and advise during (water polution) calamities.

van Loenen, A.; van Dijk, M.; van Verseveld, W.; Berger, H.

2012-04-01

425

Water Supply Infrastructure System Surety  

SciTech Connect

The executive branch of the United States government has acknowledged and identified threats to the water supply infrastructure of the United States. These threats include contamination of the water supply, aging infrastructure components, and malicious attack. Government recognition of the importance of providing safe, secure, and reliable water supplies has a historical precedence in the water works of the ancient Romans, who recognized the same basic threats to their water supply infrastructure the United States acknowledges today. System surety is the philosophy of ''designing for threats, planning for failure, and managing for success'' in system design and implementation. System surety is an alternative to traditional compliance-based approaches to safety, security, and reliability. Four types of surety are recognized: reactive surety; proactive surety, preventative surety; and fundamental, inherent surety. The five steps of the system surety approach can be used to establish the type of surety needed for the water infrastructure and the methods used to realize a sure water infrastructure. The benefit to the water industry of using the system surety approach to infrastructure design and assessment is a proactive approach to safety, security, and reliability for water transmission, treatment, distribution, and wastewater collection and treatment.

EKMAN,MARK E.; ISBELL,DARYL

2000-01-06

426

Industrial Energy Conservation, Forced Internal Recirculation Burner  

SciTech Connect

The overall objective of this research project is to develop and evaluate an industrial low NOx burner for existing and new gas-fired combustion systems for intermediate temperature (1400 degree to 2000 degree F) industrial heating devices such as watertube boilers and process fluid heaters. A multi-phase effort is being pursued with decision points to determine advisability of continuance. The current contract over Phases II and III of this work. The objectives of each phase are as follows. Phase II - to design, fabricate, and evaluate prototype burners based on the Forced Internal Recirculation (FIR) concept. Phase III - to evaluate the performance of an FIR burner under actual operating conditions in a full-scale field test and establish the performance necessary for subsequent commercialization

Joseph Rabovitser

2003-06-19

427

Dynamic simulation of large boilers with natural recirculation  

Microsoft Academic Search

This paper presents a dynamic simulator of water-in-tube boilers with natural recirculation, the kind of equipment widely used in industries for steam generation either as a source of power or for providing heating capabilities in process plants. The development is based on a combination of two non-linear models, one for the evaporation in the vertical tubes and the other for

E. J. Adam; J. L. Marchetti

1999-01-01

428

The benefits of flue gas recirculation in waste incineration.  

PubMed

Flue gas recirculation in the incinerator combustion chamber is an operative technique that offers substantial benefits in managing waste incineration. The advantages that can be obtained are both economic and environmental and are determined by the low flow rate of fumes actually emitted if compared to the flue gas released when recirculation is not conducted. Simulations of two incineration processes, with and without flue gas recirculation, have been carried out by using a commercial flowsheeting simulator. The results of the simulations demonstrate that, from an economic point of view, the proposed technique permits a greater level of energy recovery (up to +3%) and, at the same time, lower investment costs as far as the equipment and machinery constituting the air pollution control section of the plant are concerned. At equal treatment system efficiencies, the environmental benefits stem from the decrease in the emission of atmospheric pollutants. Throughout the paper reference is made to the EC legislation in the field of environmental protection, thus ensuring the general validity in the EU of the foundations laid and conclusions drawn henceforth. A numerical example concerning mercury emission quantifies the reported considerations and illustrates that flue gas recirculation reduces emission of this pollutant by 50%. PMID:16516458

Liuzzo, Giuseppe; Verdone, Nicola; Bravi, Marco

2007-01-01

429

Continuous Commissioning of a Central Chilled Water & Hot Water System  

E-print Network

A central chilled water / hot water system provides cooling / heating energy from central utility plants to multiple customers (buildings) through campus distribution loops. To effectively transport the chilled water and hot water to the buildings...

Deng, S.; Turner, W. D.; Batten, T.; Liu, M.

2000-01-01

430

Systems and Components Fuel Delivery System, Water Delivery System, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur , Huntsville, Madison County, AL

431

Pennsylvania Stream Water Treatment Systems  

NSDL National Science Digital Library

The video asks who will be around to keep water treatment systems going, monitor the quality of streams, and create new initiatives to keep water sources clean. A number of programs address these issues and get young people involved in environmental and conservation activities.

Wpsu

2007-04-04

432

Dry scrubbing of acid gases in recirculating cyclones.  

PubMed

This paper describes a laboratory-scale study on the use of recirculating cyclones as reaction chambers for dry scrubbing of gaseous HCl with solid slaked lime particles. This gas cleaning system combines a numerically optimized reverse flow gas cyclone (RS_VHE geometry) with a straight-through cyclone concentrator, which simultaneously increases the capture of the solid particles and promotes their partial recirculation. A laboratory-scale study was undertaken to test this technology and to compare its performance to a modified Stairmand HE reverse flow cyclone without recirculation. The experimental conditions were: reaction temperature approximately 326 K, gas flow rate approximately 2.9 x 10(-4) Nm(3) s(-1) and relative humidity of the gas approximately 8.5%. The experimental variables tested were the solids load (1.0-9.2 x 10(-7) kg s(-1)) and HCl concentration (0.4-2.8 x 10(-2) mol m(-3)) in the inlet gas. The experimentally obtained particulate removal efficiencies with the recirculating cyclones ( approximately 98%) were higher than those obtained with the Stairmand HE cyclone ( approximately 93%), with the additional advantage of having significantly lower pressure drop. As for the acid removal efficiencies ( approximately 10-96%), no significant differences were found between the two systems tested under the same experimental conditions. The possibility of using optimized recirculating cyclones for gas cleaning in a dry scrubbing process is very promising, since this is a low cost technology, highly efficient both for the removal of acid gases and for the capture of solid particles, which has the advantage of not requiring a post-reaction de-duster. PMID:17360111

Chibante, Vânia; Fonseca, Ana; Salcedo, Romualdo

2007-06-18

433

AGENT-BASED WATER\\\\WASTE WATER CONTROL SYSTEM ARCHITECTURE  

Microsoft Academic Search

The control system for a municipal water system needs to meet the criteria of maintaining continuity and reliability in the water supply for satisfying the consumer demand while saving the energy costs and maintaining the quality of water. In this paper, we propose an intelligent agent system for a municipal water system. This work shows the benefits of using the

Francisco Maturana; Radhika Kotina; Raymond Staron; Pavel Tichý; Pavel Vrba

2006-01-01

434

Water-based intumescent paint  

NASA Technical Reports Server (NTRS)

Article discusses fire-resistant water-based paints made by adding intumescing agents to fluorocarbon coatings. Since these paints are water-based, they do not pollute atmosphere as they dry and can be used in closed-loop air-recirculation system in spacecraft and submarines.

Sauers, D. G.; Nannelli, P.

1979-01-01

435

Clean Water Systems in Mexico  

NSDL National Science Digital Library

In this video segment adapted from Rx for Survival, learn about the importance of clean water and sanitation systems. Hear the story of how, in the early 1990s, Mexico's entry into a North American trade agreement was threatened by a cholera epidemic. Find out how the Mexican government rebuilt the water and sanitation system to stop the spread of the disease and how the investment in clean water helped the country win the trade agreement. A background essay, discussion questions, and standards correlations are also provided.

2010-08-31

436

Ephesus Municipal Water System Analysis  

NSDL National Science Digital Library

This project examines the entire water system of an ancient city, including supply, distribution, use, and drainage. Until now, individual water system elements have been studied as archaeological objects, but infrequently subjected to analysis by such disciplines as fluids engineering and urban history. This work is part of two larger long-term studies, the first concerning the relationship between physical setting and urban growth in the Greco-Roman world, and the second a comparative study of Old and New World water management techniques in the pre-modern period.

Crouch, Dora P.; Ortloff, Charles

1997-12-05

437

Conceptual design description for the tritium recovery system for the US ITER (International Thermonuclear Experimental Reactor) Li sub 2 O\\/Be water cooled blanket  

Microsoft Academic Search

The tritium recovery system for the US ITER LiâO\\/Be water cooled blanket processes two separate helium purge streams to recover tritium from the LiâO zones and the Be zones of the blanket, to process the waste products, and to recirculate the helium back to the blanket. The components are selected to minimize the tritium inventory of the recovery system, and

P. A. Finn; D. K. Sze; R. G. Clemmer

1990-01-01

438

Conceptual design description for the tritium recovery system for the US ITER Li sub 2 O\\/Be water cooled blanket  

Microsoft Academic Search

The tritium recovery system for the US ITER LiâO\\/Be water cooled blanket processes two separate helium purge streams to recovery tritium from the LiâO zones and the Be zones of the blanket, to process the waste products, and to recirculate the helium back to the blanket. The components are selected to minimize the tritium inventory of the recovery system, and

P. A. Finn; D. K. Sze; R. G. Clemmer

1990-01-01

439

Ground Water Cooling System  

E-print Network

has a total shop area of 128,000 square feet and the majority of the machine tools are equipped with computerized numerical controls. The cooling system was designed around five (5) floor mounted, 50,000 CFM, air handling units which had been...

Greaves, K.; Chave, G. H.

1984-01-01

440

Clemson University Water System Clemson, SC  

E-print Network

of our test results that are listed in this report labeled Duke Power Water System Water Quality Table1 Clemson University Water System Clemson, SC 2001 Annual Water-Quality Report Clemson University water. We test our water using sophisticated equipment and advanced procedures. The water supplied

Duchowski, Andrew T.

441

65 FR 49060 - National Pollutant Discharge Elimination System-Regulations Addressing Cooling Water Intake...  

Federal Register 2010, 2011, 2012, 2013

...needed to support section 316(b) decisions and presenting...screening systems, size...historical decision-making...require the support of a multi-disciplinary...that might support a decision not to relocate...recirculating system to...

2000-08-10

442

Clemson University Water System Clemson, SC  

E-print Network

of our test results that are listed in this report labeled Duke Power Water System Water Quality Table Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL MCLG Avg1 Clemson University Water System Clemson, SC 1999 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

443

Clemson University Water System Clemson, SC  

E-print Network

of our test results that are listed in this report labeled Duke Power Water System Water Quality Table Turbidity Units #12;2 Duke Power Water System Water Quality Table Contaminant Date Tested Unit MCL MCLG Avg1 Clemson University Water System Clemson, SC 2000 Annual Water-Quality Report Clemson University

Duchowski, Andrew T.

444

Cyclone reactor with internal separation and axial recirculation  

DOEpatents

A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture. The partition plate divides the apparatus into a cylindrical precombustor chamber and a combustor chamber. A coal-water slurry is passed axially into the inlet end of the precombustor chamber, and primary air is passed tangentially into said chamber to establish a cyclonic air flow. Combustion products pass through the partition plate aperture and into the combustor chamber. Secondary air may also be passed tangentially into the combustor chamber adjacent the partition plate to maintain the cyclonic flow. Flue gas is passed axially out of the combustor chamber at the outlet end and ash is withdrawn tangentially from the combuston chamber at the outlet end. A first mixture of flue gas and ash may be tangentially withdrawn from the combustor chamber at the outlet end and recirculated to the axial inlet of the precombustor chamber with the coal-water slurry. A second mixture of flue gas and ash may be tangentially withdrawn from the outlet end of the combustor chamber and passed to a heat exchanger for cooling. Cooled second mixture is then recirculated to the axial inlet of the precombustor chamber. In another embodiment a single cyclone combustor chamber is provided with both the recirculation streams of the first mixture and the second mixture.

Becker, Frederick E. (Reading, MA); Smolensky, Leo A. (Concord, MA)

1989-01-01

445

Cyclone reactor with internal separation and axial recirculation  

DOEpatents

A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture is described. The partition plate divides the apparatus into a cylindrical precombustor chamber and a combustor chamber. A coal-water slurry is passed axially into the inlet end of the precombustor chamber, and primary air is passed tangentially into said chamber to establish a cyclonic air flow. Combustion products pass through the partition plate aperture and into the combustor chamber. Secondary air may also be passed tangentially into the combustor chamber adjacent the partition plate to maintain the cyclonic flow. Flue gas is passed axially out of the combustor chamber at the outlet end and ash is withdrawn tangentially from the combustor chamber at the outlet end. A first mixture of flue gas and ash may be tangentially withdrawn from the combustor chamber at the outlet end and recirculated to the axial inlet of the precombustor chamber with the coal-water slurry. A second mixture may be tangentially withdrawn from the outlet end and passed to a heat exchanger for cooling. Cooled second mixture is then recirculated to the axial inlet of the precombustor chamber. In another embodiment a single cyclone combustor chamber is provided with both the recirculation streams of the first mixture and the second mixture. 10 figs.

Becker, F.E.; Smolensky, L.A.

1988-07-19

446

Lattice Design for the LHEC Recirculating Linac  

SciTech Connect

In this paper, we present a lattice design for the Large Hadron Electron Collider (LHeC) recirculating linac. The recirculating linac consists of one roughly 3-km long linac hosting superconducting RF (SRF) accelerating cavities, two arcs and one transfer line for the recirculation. In two passes through a pulsed SRF linac the electron beam can get a maximum energy of 140 GeV. Alternatively, in the Energy Recovery Linac (ERL) option the beam passes through a CW linac four times (two passes for acceleration and two for deceleration) for a maximum energy of 60 GeV.

Sun, Yipeng; /CERN; Eide, Anders; /CERN; Zimmermann, Frank; /CERN; Adolphsen, Chris; /SLAC

2011-05-20

447

Picosecond Pulse Recirculation for High Average Brightness Thomson Scattering-based Gamma-ray Sources  

SciTech Connect

Pulse recirculation has been successfully demonstrated with the interaction laser system of LLNL's Thomson-Radiated Extreme X-ray (T-REX) source. The recirculation increased twenty-eight times the intensity of the light coming out of the laser system, demonstrating the capability of increasing the gamma-ray flux emitted by T-REX. The technical approach demonstrated could conceivably increase the average gamma-ray flux output by up to a hundred times.

Semenov, V

2009-05-28

448

Digital feedwater and recirculation flow control for GPUN Oyster Creek  

SciTech Connect

This paper describes the digital system for feedwater and recirculation control that GPU Nuclear will be installing at Oyster Creek during its next outage - expected circa December 1992. The replacement was motivated by considerations of reliability and obsolescence - the analog equipment was aging and reaching the end of its useful life. The new system uses Atomic Energy of Canada Ltd.'s software platform running on dual, redundant, industrial-grade 386 computers with opto-isolated field input/output (I/O) accessed through a parallel bus. The feedwater controller controls three main feed regulating valves, two low flow regulating valves, and two block valves. The recirculation controller drives the five scoop positioners of the hydraulic couplers. The system also drives contacts that lock up the actuators on detecting an open circuit in their current loops.

Burjorjee, D. (Atomic Energy of Canada Ltd., Mississauga, Ontario (Canada)); Gan, B. (GPU Nuclear Corp., Parsippany, NJ (United States))

1992-01-01

449

The global water systems project  

NASA Astrophysics Data System (ADS)

The Global Water System (GWS) plays a central and integrative role in the dynamics of the Earth system. It is a regulator of biogeophysical and biogeochemical processes, and it is also is essential for sustenance of human societies. The GWS is increasingly modified by humans and through climate effects (facets of it have moved well outside the range of natural variability), without adequate understanding of how the system works. For understanding the changes, feedbacks and potentially critical thresholds within the Earth system, and eventually for better managing the GWS, new synthetic knowledge is required. The Global Water System Project (GWSP) is a new activity being undertaken jointly by the World Climate Research Programme (WCRP), International Geophshere-Biosphere Program (IGBP), International Human Dimensions Program (IHP), and Diversitas. It will address the GWS in a comprehensive fashion at the global scale, building upon the emerging new consolidated Earth systems data sets, global monitoring tools, and predictive and coupled modeling capabilities. The central scientific question that motivates the GWSP is: "How are humans changing the global water cycle, the associated biogeochemical cycles, and the biological components of the GWS, and what are the social feedbacks arising from these changes?" GWSP will be structured around three "framing questions": a) What are the relative magnitudes of global-scale changes in the global water system that are attributable to changing human activities, and to environmental factors such as climate variability and change?; b) What are the main mechanisms by which human activities are affecting the global water system; and c) To what extent is the global water system resilient to global change? Examples of issues that might be addressed under each of these questions are provided.

Hoff, H.; Jaeger, C.; Leveque, C.; Lettenmaier, D.; Lins, H.; Meybeck, M.; Niasse, M.; Vorosmarty, C.

2003-04-01

450

Drinking Water Distribution Systems Hydraulics, Leakage, and Water Quality Issues  

E-print Network

water pipes!! #12; It is demonstrated that hydraulic transients in water mains have high potential#12; Drinking Water Distribution Systems Hydraulics, Leakage, and Water Quality Issues Life Cycle Assessment for Different Piping Materials Water Demand Analysis due to Water Meter Installation

Su, Xiao

451

Water in clay-water systems (1) Philip F. LOW  

E-print Network

Water in clay-water systems (1) Philip F. LOW Department of Agronomy, Purdue University. Agric. Exp. Stn., West Lafayette, IN 47907, U.S.A. SUMMARY The swelling of clay-water systems and the thermodynamic, hydrodynamic and spectroscopic properties of water in these systems are discussed. The swelling

Paris-Sud XI, Université de

452

A millenarian water rights system and water markets in Oman  

Microsoft Academic Search

Centuries ago, water scarcity in Oman led to the development of a system of water allocation based on water rights, the falaj. Both the existence of water rights and the management system largely explain why the falaj system has continued to exist for centuries. This paper addresses the falaj from a management point of view to show what makes this

Slim Zekri; Ahmed Salim Al-Marshudi

2008-01-01

453

WATER AND WASTEWATER SYSTEMS IN IMPERIAL ROME  

Microsoft Academic Search

Ancient Rome is famous for its water and wastewater systems. This paper is a discussion of the impact these systems had on living conditions in the imperial city. Rome's water system provided a constant supply to centrally located areas, in contrast to modern systems which deliver water on demand to individ- ual connections. For both water and wastewater systems, access

Roger D. Hansen

454

Fant's Grove Water System Clemson, SC  

E-print Network

1 Fant's Grove Water System Clemson, SC 2002 Annual Water-Quality Report Clemson University water. We test our water using sophisticated equipment and advanced procedures. The water supplied by Clemson University Water System meets state and federal standards for both appearance and safety

Duchowski, Andrew T.

455

Clemson University Water System Clemson, SC  

E-print Network

1 Clemson University Water System Clemson, SC 2002 Annual Water-Quality Report Clemson University water. We test our water using sophisticated equipment and advanced procedures. The water supplied by Clemson University Water System meets state and federal standards for both appearance and safety

Duchowski, Andrew T.

456

An ambient water loop system for USP purified water  

Microsoft Academic Search

An ambient loop USP purified water system has been designed and implemented using carbon and ion exchange resin beds, ultraviolet light systems and polishing filters to produce water consistently meeting or exceeding all USP XXIII quality specifications for purified water. The circulation system is constructed of PVDF plastic piping material installed in a continuous fully-drainable loop. The system was sized

B. H. Junker; M. Stanik; J. Adamca; K. LaRiviere; M. Abbatiello; P. Salmon

1997-01-01

457

Milli-Q Reference Water Purification System  

E-print Network

schematic on the next page shows how the water is purified and delivered by the system. Convenience in waterMilli-Q® Reference Water Purification System The reference for ultrapure water systems EMD Millipore is a division of Merck KGaA, Darmstadt, Germany #12;Ultrapure Water by EMD Millipore Scientists

Woodall, Jerry M.

458

Information Sources for Small Water Systems  

E-print Network

Managers of small waters systems must have information about a variety of topics. This publication lists essential printed and electronic resources on disaster preparedness, national drinking water standards, private water well management, water...

Dozier, Monty; Theodori, Gene L.; Jensen, Ricard

2007-02-19

459

National Water Information Systems A Tool to Support Integrated Water  

E-print Network

the drafting of a National Water Policy in 2008 · Multi-stakeholder collaboration under the Caribbean Water water specialists and decision- makers with tools for developing IWRM policies. · Development of GrenadaNational Water Information Systems A Tool to Support Integrated Water Resources Management

Barthelat, Francois

460

Water pressure booster system selection  

SciTech Connect

Offers guidelines on type of water pumping system to be used (constant or variable speed) and system split (breakdown of 100% system load into 2 or more pumps, with number and type of pumps taken into account). Variable speed control (e.g. SCR type) is justified where an extreme variable in suction pressure exists. Experience based on power studies, metering, and observation of various installations dictates a ''normal'' system split of 3 pumps, rated 25, 55 and 55% of peak demand. A specific application or system size may merit modification, but each should have the capability of: 80% minimum residual capacity and use of a ''workhorse'' lead pump to handle low flow requirements. System sizing is the primary consideration in the proper selection of a booster system.

Anderson, G.W.

1983-01-01

461

Water sample-collection and distribution system  

NASA Technical Reports Server (NTRS)

Collection and distribution system samples water from six designated stations, filtered if desired, and delivers it to various analytical sensors. System may be controlled by Water Monitoring Data Acquisition System or operated manually.

Brooks, R. R.

1978-01-01

462

WATER DISTRIBUTION SYSTEM OPERATION: APPLICATION OF  

E-print Network

CHAPTER 5 WATER DISTRIBUTION SYSTEM OPERATION: APPLICATION OF SIMULATED ANNEALING Fred E. Goldman Arizona State University, Tempe, Arizona 5.1 INTRODUCTION The operation of water distribution systems affects the water quality in these systems. EPA regulations require that water quality be maintained

Mays, Larry W.

463

Total Water Management, the New Paradigm for Urban Water Systems  

EPA Science Inventory

There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current resource management practices put different stresses on local water resources and urban infrastructure. Total Water Manag...

464

Liquid hydrogen and liquid oxygen feedline passive recirculation analysis  

NASA Astrophysics Data System (ADS)

During the National Launch System design phase, a computer code (FEEDLINE) was written to analyze the feasibility of using passive recirculation propellant conditioning for the LH2 and LO2 feed systems. The FEEDLINE code was employed to provide temperature profiles to the STME design team. The team used the temperature profiles to determine if the required Space Transportation Main Engine net positive suction pressure was met. One desired outcome of the LH2 testing was to determine if modifications are required for the FEEDLINE code. The initial LN2 calibration tests indicate that the environmental heat into the system decreases with increasing heater input.

Holt, Kimberly A.; Cleary, Nicole L.; Nichols, Andrew J.; Perry, Gretchen L. E.

465

MINIMIZATION OF WATER USE IN LEAFY VEGETABLE WASHERS  

EPA Science Inventory

This project was undertaken to construct and test an improved leafy greens washing system employing water recirculation, to characterize the quality of the wash water and waste stream and to make comparisons to conventional washers. The prototype system produced a cleaner product...

466

Recirculation Bubbles Measured at the Black Rock Forest Site in New York  

NASA Astrophysics Data System (ADS)

In conditions of low or moderate wind speed, large eddy structures - or recirculation bubbles - may form in the atmosphere over complex terrain. Recirculating air can have a significant influence on the exchange of moisture, energy and trace gases between the atmosphere and biosphere. Recirculation bubbles were predicted by an analytical model (Wang and Yi, 2012), and a numerical model (Xu and Yi, 2012). We conducted an experiment using two nearby towers in Black Rock Forest, New York, confirming the predicted phenomenon. Sensors were installed at five different levels on a tower at the top of a forested hill, and at five different levels at the middle of the eastern slope of the same hill. Each tower contained sensors both above and within the canopy measuring wind speed and direction, temperature, carbon dioxide, water vapor, relative humidity, net radiation, ground heat flux and other key parameters. Sensors collected data from 20 April to 9 June, 2013. The energy flux balances at the tops of the hilltop and midslope towers were approximately 75% and 85% of closure, respectively. The formation of recirculation bubbles was observed to be dependent on wind speed and direction, terrain features, temperature gradients and prevailing synoptic conditions. Carbon dioxide, water vapor and temperature profiles show that net ecosystem exchange is influenced by the presence or absence of recirculation. This research was supported by NSF Grants ATM-0930015 and PSC-CUNY ENHC-44-83.

Kutter, E.; Yi, C.; Hendrey, G. R.; Liu, H.; Eaton, T. T.; Ni-Meister, W.

2013-12-01

467

Experiments With Recirculating Target for F-18 Production  

SciTech Connect

Approximately 10 ml of O-18 water was loaded in an apparatus containing a 5 ml storage vessel, pump, silver target attached to a cyclotron, filter, backpressure regulator, conductivity meter, several valves and ion exchange cartridges. The water was continuously pumped through the target during proton bombardment at a rate 5 ml/min. Continuous irradiation with beam current ranging from 10 to 50 uA was conducted while pressure, temperature and conductivity were continuously monitored. The results indicate that recirculating of the target water can increase production of F-18 in relation to consumed O-18 water material. It can also increase productivity by eliminating idle periods for re-filling the target. A backpressure regulator can precisely control target pressure. This method also allows for continuous monitoring of the target material temperature, pressure, conductivity and accumulated radioactivity. Results of these observations provide important information about target performance and physical processes taking place inside the target.

Kiselev, M.Y. [Eastern Isotopes, Inc. Sterling, VA (United States)

2003-08-26

468

Effect of makeup water properties on the condenser fouling in power planr cooling system  

SciTech Connect

The thermoelectric power industry in the U.S. uses a large amount of fresh water. As available freshwater for use in thermoelectric power production becomes increasingly limited, use of nontraditional water sources is of growing interest. Utilization of nontraditional water, in cooling systems increases the potential for mineral precipitation on heat exchanger surfaces. In that regard, predicting the accelerated rate of scaling and fouling in condenser is crucial to evaluate the condenser performance. To achieve this goal, water chemistry should be incorporated in cooling system modeling and simulation. This paper addresses the effects of various makeup water properties on the cooling system, namely pH and aqueous speciation, both of which are important factors affecting the fouling rate in the main condenser. Detailed modeling of the volatile species desorption (i.e. CO{sub 2} and NH{sub 3}), the formation of scale in the recirculating system, and the relationship between water quality and the corresponding fouling rates is presented.

Safari, I.; Walker, M.; Abbasian, J.; Arastoopour, H.; Hsieh, M-K.; Dzombak, D.; Miller, D.

2011-01-01

469

The northern recirculation gyre of the gulf Stream  

NASA Astrophysics Data System (ADS)

Results from two recent field programsin the western North Atlantic are presented with particular emphasis on the deep circulation. New long-term moored current measurements show that the flow north of the Gulf Stream and east of the New England Seamount Chain is toward the west from 500 m to the bottom with very little depth dependence. Nearly 40 × 10 6 m 3s -1 is transported to the west near 63°W, and half of this recirculates back to the east over the Seamount Chain to add a strong component to the deep Gulf Stream between the Chain and the Grand Banks. We call this current the "Northern Recirculation Gyre" in contrast with a similar feature to the south of the Stream popularly known as the "Worthington Gyre" ( WORTHINGTON, 1976, The Johns Hopkins Oceanographic Studies, 6, 110 pp.). The new gyre is similar to that proposed by HOGG (1983, Deep-Sea Research, 30, 945-961) but somewhat smaller in scale. Its relationship to the Gulf Stream and the Deep Western Boundary Current is made explicit by the new measurements. Tracer measurements show that the Northern Recirculation Gyre exchanges water properties with the Deep Western Boundary Current where the two are in close proximity along the northern boundary. The relatively high values of oxygen and freon, so imparted, are then advected to the interior where the gyre carries water eastward under the Gulf Stream. Beneath the thermocline these tracer fields are practically homogenous within the gyre, perhaps a reflection of the expulsion process described by RHINES and YOUNG (1983, Journal of Fluid Mechanics, 133, 133-145). An advective-diffusive model is used to interpret some slight differences between the various tracer distributions.

Hogg, Nelson G.; Pickart, Robert S.; Hendry, Ross M.; Smethie, William J.

1986-09-01

470

Water: Life's Elixir in the Solar System  

NSDL National Science Digital Library

This article discusses the possible occurrence of water in our solar system. Topics include the necessity of liquid water for life, distribution of water throughout the solar system, and the possibility that there may be liquid water on Mars or on some of Jupiter's moons.

471

Ozone Treatment in Cooling Water Systems  

Microsoft Academic Search

Ozone treatment for preventing the biofouling in cooling water systems is investigated.In the fresh water system, the separating effect of the ozonated water on the microorganisms such as the sphaerotilus and the zoogloea which adhere to the piping and form the slime is recognized. When the ozonated water is supplied intermittently to the piping without stopping the flow of the

N. Kaiga; T. Seki; K. Iyasu

1989-01-01

472

Generation and maintenance of recirculations by Gulf Stream instabilities  

E-print Network

This thesis studies the problems of generation and maintenance of recirculations by Gulf Stream instabilities. Observations show that the horizontal structure of the jet and its recirculations suffer significant changes ...

Beliakova, Natalia Yurievna, 1967-

1999-01-01

473

Water Resource System Optimization by Geometric Programming  

E-print Network

Water resources planners and systems analysts are continually confronted with many complex optimization problems. Two major factors contribute to this problem. Firstly, mathematical modeling and system description capabilities in water resources...

Meier, W. L.; Shih, C. S.; Wray, D. J.

474

Performance of the liquid reactivity control system in BWRs (boiling water reactors)  

SciTech Connect

Boiling water reactors rely on the injection of soluble neutron absorbers to control power in case of failure in the control rod (scram) system. Typically this liquid poison'' is injected from eight small holes on a standpipe positioned vertically near the outer edge of the core shroud in the lower plenum. The achievement of control is predicated on good mixing of this injected liquid with the coolant which is recirculating around the core upper plenum and downcomer. However, because the flows are rather low ({approximately}20% of rated with pumps tripped as expected under such conditions) and the injected solution density is much higher than that of the primary fluid, there have been concerns raised about the efficiency and completeness of this mixing. This work provides the first openly available data addressing such concerns. To avoid potentially important scaling compromises, the data were obtained from full-scale simulations. From the experiments performed so far, we can conclude that complete boron mixing (entrainment) will occur for recirculation flow rates down to 8.2% of rated. 3 refs., 60 figs., 2 tabs.

Theofanous, T.G.; Shabana, E.A. (California Univ., Santa Barbara, CA (USA). Dept. of Chemical and Nuclear Engineering)

1989-09-01

475

Variable percentage exhaust gas recirculation valve  

Microsoft Academic Search

An exhaust gas recirculation (EGR) valve for an internal combustion engine is disclosed in which the rate of flow of exhaust gas from the outlet manifold to the inlet manifold of the engine is controlled as a function of engine load and speed.

1978-01-01

476

High speed exhaust gas recirculation valve  

Microsoft Academic Search

In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and

Rod Fensom; David J. Kidder

2005-01-01

477

WATER QUALITY EFFECTS RELATED TO BLENDING WATERS IN DISTRIBUTION SYSTEMS  

EPA Science Inventory

This study was conducted to evaluate the effects of blending two or more waters of different quality and to relate their composition to the corrosive effects and calcium carbonate deposition tendency of the water on distribution systems. The EPA mobile water quality monitoring la...

478

Solar water cost and feasibility of solar water heating system  

Microsoft Academic Search

The present research work has been carried out on 1,000 litre installed capacity solar water heating system, at Jijau Hostel, Dr Panjabrao Deshmukh Agricultural University (PDKV), Akola, Maharashtra, India. The main objectives were to evaluate various costs and benefits involved in the solar water production. The costs of hot water production per litre with comparison to electrical energy were calculated

Vivek P. Khambalkar; Sharashchandra R. Gadge; Dhiraj S. Karale

2009-01-01

479

COST OPTIMIZATION OF WATER DISTRIBUTION SYSTEMS SUBJECTED TO WATER HAMMER  

Microsoft Academic Search

The paper presents the water distribution systems optimization by selecting the optimal pipe diameters for water hammer transients. The optimization method used is the Genetic Algorithm (GA). The GA's have been used in solving the water network optimization for steady state conditions. The GA is integrated with the steady state hydraulic analysis program and a transient analysis program to improve

Berge Djebedjian; Mohamed S. Mohamed; Abdel-Gawad Mondy

2009-01-01

480

Low NOx Combustion of DME by Means of Flue Gas Recirculation  

NASA Astrophysics Data System (ADS)

This study focuses on the fundamental characteristics of DME (Dimethyl Ether) combustion aiming at development of low-NOx combustion technology with flue gas recirculation, FGR. The flue gas is recirculated into the combustion chamber to reduce the oxygen concentration and to suppress the combustion gas temperature, so that NOx emission is significantly reduced. The fuel gas recirculation at high mixing ratio, however, may lead to unstable combustion of conventional fuels, methane or city gas. On the other hand, DME has very high potential of applicability for the flue gas recirculation even at high mixing ratio because of its high burning velocity and low ignition temperature. Combustion tests were conducted with laboratory-scale 11kW combustor. The maximum FGR ratio is 85% at the initial air ratio of 1.5 with preheated diluted air about 600K. The NOx emission reduced to 13ppm at 0%-O2, which corresponds to about 9% of NOx emission at FGR=0%. The stable combustion is sustained even in the low oxygen concentration by preheating diluted-air up to near the auto-ignition temperature of DME. Finally, the effect of the flue gas recirculation on the NOx and CO emission is discussed with reference to the industrial-scale water-tube boilers.

Matsumoto, Ryosuke; Ozawa, Mamoru; Terada, Shinya; Iio, Takenori

481

Effects of viscosity and bottom friction on recirculating flows  

NASA Astrophysics Data System (ADS)

A recent set of coastal experiments (Pattiaratchi et al., 1987), found that the horizontal eddy Reynolds number did not adequately describe the wakes found in the lee of coastal islands. Other flow parameters formulated on bottom friction were found to be much better at describing these wakes. In this paper it is suggested that these findings are caused by the extraction of energy from the flow due to bottom friction, which is the net result of the vertical viscous transfer of momentum through the water column to the seabed. This is in contrast to the horizontal viscous transfer of momentum which results in negligible energy loss to the coast, because of the far larger horizontal scales. It is hypothesized that this difference results in fundamentally different flow regimes and this hypothesis is investigated both analytically and numerically. Conditions for the existence of steady zones of barotropic recirculation under the influence of both horizontal viscosity and bottom friction in the wake behind a bluff body are examined analytically. It is found that such steady recirculation requires the presence of horizontal viscosity and is hindered by the loss of energy due to bottom friction. A numerical model is used to verify and quantify this analytical result for the case of two-dimensional flow around a circular cylinder, and it is concluded that an appropriate bottom friction number, based on the ratio of scales of the nonlinear and bottom friction terms, may often govern the nature of the recirculation in the lee of coastal islands, instead of the eddy Reynolds number based on horizontal eddy viscosity, as is sometimes assumed.

Denniss, Tom; Middleton, Jason H.

1994-05-01

482

Asymmetric loads on a BWR shroud during blowdown after a recirculation line break  

SciTech Connect

The reactor core in boiling water reactors is surrounded by a cylindrical steel shroud. In 1994 routine inspection revealed surface cracks in the shroud welds. These cracks have led to the concern that the damaged shrouds would not be able to withstand the loads encountered during loss of coolant accidents. This paper discusses the load caused by a recirculation line break.

Gillis, J.C. [Levy Associates, Campbell, CA (United States)

1995-12-31

483

Pilot-scale cooling tower to evaluate corrosion, scaling, and biofouling control strategies for cooling system makeup water  

NASA Astrophysics Data System (ADS)

Pilot-scale cooling towers can be used to evaluate corrosion, scaling, and biofouling control strategies when using particular cooling system makeup water and particular operating conditions. To study the potential for using a number of different impaired waters as makeup water, a pilot-scale system capable of generating 27 000 kJ/h heat load and maintaining recirculating water flow with a Reynolds number of 1.92 × 104 was designed to study these critical processes under conditions that are similar to full-scale systems. The pilot-scale cooling tower was equipped with an automatic makeup water control system, automatic blowdown control system, semi-automatic biocide feeding system, and corrosion, scaling, and biofouling monitoring systems. Observed operational data revealed that the major operating parameters, including temperature change (6.6 °C), cycles of concentration (N = 4.6), water flow velocity (0.66 m/s), and air mass velocity (3660 kg/h m2), were controlled quite well for an extended period of time (up to 2 months). Overall, the performance of the pilot-scale cooling towers using treated municipal wastewater was shown to be suitable to study critical processes (corrosion, scaling, biofouling) and evaluate cooling water management strategies for makeup waters of complex quality.

Chien, S. H.; Hsieh, M. K.; Li, H.; Monnell, J.; Dzombak, D.; Vidic, R.

2012-02-01

484

Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation  

NASA Technical Reports Server (NTRS)

This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

2008-01-01

485

BIOFILM IN DRINKING WATER DISTRIBUTION SYSTEMS  

EPA Science Inventory

Throughout the world there are millions of miles of water distribution pipe lines which provide potable water for use by individuals and indu