The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform
Zheng Hua-ping - One of the best experts on this subject based on the ideXlab platform.
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A Study of Set up on the Work Pressure Difference between the Internal and the External Automatic Self-Suction Filter Screen in Micro-irrigation
China Rural Water and Hydropower, 2010Co-Authors: Zheng Hua-pingAbstract:A Filter is an essential equipment dealing with the irrigation water containing sand in micro-irrigation projects.By predicting pressure between the inside and the outside of the thin Filter screen,the filtration and backwashing characteristics of the automatic self-Suction Filter in micro-irrigations are studied.In the process of Filtering,the sand in the inner surface of the Filter screen gradually increases as the Filtering time goes on,resulting in the increase of the pressure between the inner and the outer.However,the Filter needs backwashing when the pressure is greater than the default value.If the default value is too large,the Filtering time will become longer,but it will decrease the life of the Filter screen because of enduring greater pressure.On the contrary,the Filtering time will be shorter,but backwashing will become frequent,and it will also influence the efficiency of filtration,so how to make the default value becomes very important.Through the theoretical calculation,it is shown that variety of the default value between the inner and outer Filter screen is0.021~0.086 MPa.Through the experiment with the 80 screen automatic self-Suction Filter,considering Filtering time,Filtering flow,head-loss etc,it is concluded that the Filter can work very efficiently when the default value is 0.08 MPa.
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Discussion of Filter and Driving Devices Based on Screen Filter
Journal of Filtration & Separation, 2010Co-Authors: Zheng Hua-pingAbstract:Self-cleaning screen Filter is a silt Filter device which is extensively applied to micro-irrigation system headquarters.This passage introduces a screen Filter which utilizes waterpower revolve nozzle to rinse automatically,based on combining its operation principle with structure character,mainly to discuss the interior construction and driving method of the Filter,which will offer reference for the design and development of new automatic self-Suction Filter samples.
Werner Kloas - One of the best experts on this subject based on the ideXlab platform.
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An innovative Suction Filter device reduces nitrogen loss in double recirculating aquaponic systems
Aquacultural Engineering, 2018Co-Authors: Johanna Suhl, Dennis Dannehl, Daniela Baganz, Uwe Schmidt, Werner KloasAbstract:Abstract The increase of global population causes rising food demand and concomittantly scarcity of resources. These facts including global warming need the further development of resource-efficient food production systems such as double recirculating aquaponic systems (DRAPS). This recent technology is suitable for intensive food production with minimal resource input and maximal reduction of emissions. In DRAPS fish water can be adjusted for plant growth (pH, nutrients) and both species are produced separately under optimum conditions. Primarily, the present study was conducted to investigate the improvement of DRAPS by implementation of an innovative Suction Filter device and, in addition, it is the first empiric investigation of combined African catfish (Clarias gariepinus) and tomato (Solanum lycopersicum L., cv. Pureza) production in DRAPS. Due to an immense loss of nitrogen caused by the primary sedimentation unit as connection between the fish and plant parts, the original DRAPS was modified by a new developed Suction Filter device to remove solid particles at minimal nitrogen loss. The nitrogen loss was significantly reduced by that system modification (≈43%) and thus resulted in a quite large reduction of greenhouse gas emissions due to the reduced need for manufacturing of nitrogen fertiliser. The combined production of African catfish and tomatoes in aquaponics revealed similar fruit yields of tomatoes as for the control using artificial fertiliser, while the overall fertiliser use in aquaponics was about 13.2–77.7% lower. However, fertiliser saving was highest after modification and replacement of the sedimentation unit by the new Suction device. In addition, in comparison to already existing aquaponic systems, the total biomass output was significantly increased. The results were evaluated under consideration of intensive crop production in hydroponics.
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Nutrient concentrations in fish waste water and its potential to use it for tomato production in double recirculating aquaponic systems
2017Co-Authors: Johanna Suhl, Dennis Dannehl, Daniela Baganz, Uwe Schmidt, Werner KloasAbstract:Double recirculating aquaponic systems (DRAPS), also referred to as decoupled aquaponics, are an effective system to combine the production of fish and plants. The fish waste water used to irrigate plants in hydroponics can be adjusted by addition of mineral fertilizer and acid for an optimal plant growth. The decoupling of fish and plant production into two independent working systems provides the possibility to intensify the production of these species up to a level reached in single production units. To keep the vision of a sustainable food production system, a maximal nutrient efficiency must be provided. As such, it is necessary to minimize the nutrient losses during the transfer from the recirculating aquaculture system (RAS) for fish rearing to the hydroponic unit. Up to date, no adequate technology for online nutrient measurement is available at the market. As such, only a subsequently adjustment of the stock solution (used to adjust the fish waste water) is feasible. In this context, the knowledge of the nutrient dynamics within the fish (waste) water would be advantageous and a constant nutrient concentration would simplify the adjustment of the nutrient concentration in the fish waste water. In the present study, the nutrient concentration in a RAS, rearing African catfish, was measured and nutrient losses caused by the initial Filter system was quantified. Due to a significant loss of nutrients during its transfer, the origin DRAPS was modified by an innovative Suction Filter device. The investigations showed that the modification reduced the losses of several macro and micro nutrients. To get an overview about the stability and dynamics of the nutrients, the nutrient concentrations were measured in the modified DRAPS on 15 consecutive days. As a first result, it seems that some macro nutrients can be kept relatively stable while some micro nutrients are very fluctuating.
Johanna Suhl - One of the best experts on this subject based on the ideXlab platform.
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An innovative Suction Filter device reduces nitrogen loss in double recirculating aquaponic systems
Aquacultural Engineering, 2018Co-Authors: Johanna Suhl, Dennis Dannehl, Daniela Baganz, Uwe Schmidt, Werner KloasAbstract:Abstract The increase of global population causes rising food demand and concomittantly scarcity of resources. These facts including global warming need the further development of resource-efficient food production systems such as double recirculating aquaponic systems (DRAPS). This recent technology is suitable for intensive food production with minimal resource input and maximal reduction of emissions. In DRAPS fish water can be adjusted for plant growth (pH, nutrients) and both species are produced separately under optimum conditions. Primarily, the present study was conducted to investigate the improvement of DRAPS by implementation of an innovative Suction Filter device and, in addition, it is the first empiric investigation of combined African catfish (Clarias gariepinus) and tomato (Solanum lycopersicum L., cv. Pureza) production in DRAPS. Due to an immense loss of nitrogen caused by the primary sedimentation unit as connection between the fish and plant parts, the original DRAPS was modified by a new developed Suction Filter device to remove solid particles at minimal nitrogen loss. The nitrogen loss was significantly reduced by that system modification (≈43%) and thus resulted in a quite large reduction of greenhouse gas emissions due to the reduced need for manufacturing of nitrogen fertiliser. The combined production of African catfish and tomatoes in aquaponics revealed similar fruit yields of tomatoes as for the control using artificial fertiliser, while the overall fertiliser use in aquaponics was about 13.2–77.7% lower. However, fertiliser saving was highest after modification and replacement of the sedimentation unit by the new Suction device. In addition, in comparison to already existing aquaponic systems, the total biomass output was significantly increased. The results were evaluated under consideration of intensive crop production in hydroponics.
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Nutrient concentrations in fish waste water and its potential to use it for tomato production in double recirculating aquaponic systems
2017Co-Authors: Johanna Suhl, Dennis Dannehl, Daniela Baganz, Uwe Schmidt, Werner KloasAbstract:Double recirculating aquaponic systems (DRAPS), also referred to as decoupled aquaponics, are an effective system to combine the production of fish and plants. The fish waste water used to irrigate plants in hydroponics can be adjusted by addition of mineral fertilizer and acid for an optimal plant growth. The decoupling of fish and plant production into two independent working systems provides the possibility to intensify the production of these species up to a level reached in single production units. To keep the vision of a sustainable food production system, a maximal nutrient efficiency must be provided. As such, it is necessary to minimize the nutrient losses during the transfer from the recirculating aquaculture system (RAS) for fish rearing to the hydroponic unit. Up to date, no adequate technology for online nutrient measurement is available at the market. As such, only a subsequently adjustment of the stock solution (used to adjust the fish waste water) is feasible. In this context, the knowledge of the nutrient dynamics within the fish (waste) water would be advantageous and a constant nutrient concentration would simplify the adjustment of the nutrient concentration in the fish waste water. In the present study, the nutrient concentration in a RAS, rearing African catfish, was measured and nutrient losses caused by the initial Filter system was quantified. Due to a significant loss of nutrients during its transfer, the origin DRAPS was modified by an innovative Suction Filter device. The investigations showed that the modification reduced the losses of several macro and micro nutrients. To get an overview about the stability and dynamics of the nutrients, the nutrient concentrations were measured in the modified DRAPS on 15 consecutive days. As a first result, it seems that some macro nutrients can be kept relatively stable while some micro nutrients are very fluctuating.
Francesco Aloschi - One of the best experts on this subject based on the ideXlab platform.
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Design of Suction Filter aimed to noise reduction of reciprocating piston compressor
2019Co-Authors: Francesco AloschiAbstract:Air Piston compressor is a reciprocating machine that uses crack shaft mechanism to compress air. Usually this type of machine is quite noisy, typical noisy level are around 95[dB]. This project is meant to look for noise sources and study a strategy to reduce the sound emitted. Thesis work was developed thanks to technical support and resources of Atlas Copco group, company leader in air compressor technique. One of the last machines designed in Atlas is Pat due machine, it will be the subject studied thought this research. This paper is meant to study the fluid dynamic noise source at compressor inlet, a new inlet Filter concept will be designed according to fluid dynamics laws and tested. Finally, this thesis works will develop a method to build new acoustic Filter that can reduce the overall machine noise.
Steven G. Wilson - One of the best experts on this subject based on the ideXlab platform.
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Threatened fishes of the world: Rhincodon typus (Smith 1828) (Rhincodontidae)
Environmental Biology of Fishes, 2005Co-Authors: Brent S. Stewart, Steven G. WilsonAbstract:Common name: Whale shark (E), requin-ba- leine (Fr), tiburon ballena (Sp), squalo balena (I), butanding (Philippines), ebisuzame (Ja- pan), tofu shark (Taiwan). Conservation sta- tus: IUCN Red List VU A1b,d, A2d. CITES Appendix II since November 2002. United Nations Convention on the Law of the Sea and the United Nations Agreement on straddling fish stocks and highly migratory fish stocks. Hunting prohibited by domestic legislation or decree in Western Australia, Tasmania, Philippines, Thailand, India, Maldives, Honduras, U.S. Atlantic waters and Gulf of Mexico (territorial seas), Florida state waters, Honduras, regional waters of Belize. Identification: The largest fish on planet earth. TL to 10-12 m, rarely to 18 m, and up to 21,000 kg body mass. Dorso-ventrally flattened and very broad head with body quickly tapering from robust shoulder girth to narrow caudal peduncle. Large, transverse and near-terminal mouth. Very large gill slits. Teeth numerous and minute. Gill slits large. Eyes lateral; spiracles behind eyes. First dorsal fin considerably larger than second and inserted ca. 2/3 posterior to snout. Three prominent, dorso-lateral ridges from shoulder to tail and terminating laterally at caudal peduncle. Caudal fin semi-lunate with no prominent sub-terminal notch. Body markings unique, consisting of checkerboard pattern of light spots, horizontal stripes and vertical bars against a dark background. Distribution: Wide range in tropical and temperate waters, with seasonal aggregated abundance in tropical to subtropical waters (except Mediterranean Sea). Abundance: Unknown, but evidence of declines in several areas where hunted as evidenced by rapid, recent declines in catch per unit effort and reduced sightings in neighboring areas.. Seasonally common (several dozen or more) at several near-shore continental and island locations (e.g. Atlantic Ocean: Belize and the Gulf of Mexico. Pacific Ocean: Sea of Cortez, Galapagos Islands, Bohol Sea and Coral Sea. Indian Ocean: the Seychelles, the Maldives, Andaman Sea, Christmas Island and Western Australia (Ningaloo Reef)). Habitat and ecology: Coastal in some seasons, pelagic in others and perhaps for much of life cycle. Evidence for long-distance migrations by some sharks. Movements may be related to ocean currents, water temperature and local, seasonal biological produc- tivity. Some evidence for trans-ocean basin movements and shorter seasonal migrations. Dives to more than 1000 m, may remain at depth for hours to weeks and tolerate ambient temperatures of 5-30C. Make regular excursions between the surface and depth in search of prey. Feed primarily on dense aggregations of crustaceans (e.g. euphausiids, copepods) and baitfishes (e.g. sardines, an- chovy). Suction Filter-feeders, often assuming a head-up, tail-down posture when feeding. Young whale sharks have been found in the stomachs of a blue shark and a blue marlin. Virtually no free-ranging sharks observed at body lengths of 1-3 m. Adults have few natural predators, except perhaps for killer whales and white sharks. Reproduction: Ovoviviparous. Egg cases retained until embryos hatch. One shark captured off Taiwan had 300 embryos in utero in various developmental stages. Young ca. 55-60 cm long and 1 kg at birth and grow to 1.4 m long and 20 kg by 4 months later. Gestation duration unknown. May reproduce at 2 year intervals or more. Sexual maturity proposed at ca. 6 m and 10-30 years. Courtship and mating have never been observed. Differential distribution of sexes at among some sites suggests sexual segregation at times. Threats: Killed in coastal harpoon and net fisheries in Taiwan, the Philippines (banned in 1998), Indonesia, the Maldives (banned in 1995), India (banned in 2001) and Pakistan. Despite bans on hunting in several areas, functional enforcement is effectively minimal in most. Trade is largely driven by demand for meat for local con- sumption and fins for trade in shark fin soup market in Asia. Collisions with ships may also cause significant mortality. Greatest threats perhaps from unregulated killing and poaching in areas that may be seasonal residences for sharks that return at other seasons to distant home ranges and deterioration and destruction of important seasonal coral reef habitat feeding areas by direct exploitation of biotic and abiotic resources, coral bleaching events, and rapid climate change. Conservation recommendations: Conservation and management efforts should be coordinated at a regional and international scale with provisions for development of robust local enforcement regimes and illegal trade sanctions. Continued limits and bans on local and regional harvests and redirection to non- consumptive uses (e.g., managed ecotourism). Remarks: Several factors may make whale sharks particularly vulnerable to
