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Journal articles on the topic 'Suction water tanks'
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1
Dartnell, Lawrence. "The Thermal–Hydraulic Design of Main Feed Water Pump Suction Systems for Large Thermal Power Plant." Proceedings of the Institution of Mechanical Engineers, Part A: Power and Process Engineering 199, no. 4 (November 1985): 215–27. http://dx.doi.org/10.1243/pime_proc_1985_199_028_02.
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British domestic design practice is described for boiler feed pump suction systems associated with high level deaerator/feed water tanks in large modern power plant. The objective of thermal–hydraulic design is the provision of adequate pressure to boiler feed water pump suctions under all transient and steady state conditions to ensure continuity of water flow and reliable pump operation. Methods are available for the determination of pressure decay in feed tanks during load transients, but the successful application of mathematical relationships between pressure decay and pressure rise in suction pipework depends on the correct identification of operational circumstances. Progress in recent years has been on the identification of circumstances which produce governing conditions and has taken design practice beyond the stage established by early workers. Developed practice has been successfully applied by the Central Electricity Generating Board and its main plant contractors to forty-nine 500 MW units in coal- and oil-fired stations and to twenty-three 660 MW units in coal, oil and advanced gas-cooled reactor stations, which at 39 680 MW, constitutes the major proportion of plant in England and Wales. Aspects of plant behaviour and operation crucial to successful system design are featured. Recommendations are made for plant layout, pipework routing, tank outlet and pipework sizing, net positive suction head (NPSH) determination etc.
2
Park, Kyu-Sik, Hung-Truyen Luong, and Joonmo Choung. "Numerical Study on the Tank Heel Determination Using Smoothed Particle Hydrodynamics." Journal of Marine Science and Engineering 9, no. 9 (September 17, 2021): 1016. http://dx.doi.org/10.3390/jmse9091016.
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Tank heel minimization is a significant issue in the design of LNG fuel tanks because it is associated with stable suction pump operation and thermal shock requirements during LNG bunkering. This study examined how the LNG tank heel is minimized, maintaining a suction pump fully submerged in LNG during dynamic vessel motion. The study assumed two LNG fuel tanks mounted on the forward deck of a 50,000 deadweight class oil product carrier. Information on the dimensions and shape of the LNG fuel tank was determined from Wartsila’s brochure, and the specifications of Vanzetti’s suction pump were referred to. The LNG fuel tank and LNG heel were modeled as rigid elements and hydrodynamically smoothed-particles, respectively. The number of particles could be determined by performing even keel analyzes by adding or subtracting particles until the target head was satisfied under the gravity load. To simulate the motion of the LNG fuel tank, the pitch and roll periods and amplitudes of the ship were calculated using the DNV classification rules. Visual observations of the dynamic flow during the pitch and roll motions with respect to the ship’s center of mass showed that the roll motion was more critical from the viewpoint of the LNG heel than the pitch motion. After performing the simulations for three cycles of roll and pitch motions, the suction pump submergence was reviewed in the last cycle. Under the conditions assumed in this study, a filling ratio of 15% was determined as the minimum LNG tank heel. Although the LNG heel has customarily been determined, the LNG heel needs to be determined through hydrodynamic analyses of each vessel because it depends on the shape of the fuel tank and the vessel motion characteristics.
3
Huang, Shi Feng, Feng Wang, Hui Xu, and Xiao Xian Wei. "Research on Optimal Operation of Raw Water Pumping System Based on Hydromechanics in Waterworks." Applied Mechanics and Materials 327 (June 2013): 294–300. http://dx.doi.org/10.4028/www.scientific.net/amm.327.294.
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According to the raw water pumping system with constant speed pump and variable speed pumps based on hydromechanics in waterworks, the hydraulic simulation models were built including pump station, water tanks, suction well etc. Based on the analysis of objective function and constraints of water treatment structures and consideration of pump operation and initial water level of clean-water-tank, the compact optimal operation mathematical models were built. Finally, correctness and advantage of the mathematical models were proved by the optimal simulation of Jinshan water supply project, which provided the valuable reference for the energy-saving operation of raw water pumping system.
4
Müller, Gerson A., Fernando T. Name, Frederico C. L. Pacheco, and Carlos B. Marcondes. "Analysis of an alternative method for the study of bromeliad-associated fauna in plants with different foliar organization." Anais da Academia Brasileira de Ciências 82, no. 4 (December 2010): 903–6. http://dx.doi.org/10.1590/s0001-37652010000400012.
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The efficiency of an alternative method of collection (by suction of water) for the study of Culicidae and Chironomidae (Diptera), Scirtidae (Coleoptera) and Coenagrionidae (Odonata) in bromeliads with different foliar architecture in a restinga at Florianópolis, SC, Brazil, was studied. The alternative method was less efficient to collect Culicidae and Chironomidae (Wilcoxon test p < 0.05) and was more efficient to Scirtidae and Coenagrionidae (Wilcoxon test p > 0.05) from Aechmea lindenii. This method was less efficient to collect insects of all groups from Vriesea friburgensis (Wilcoxon test p < 0.05). The alternative method was efficient to estimate the diversity of these insects in both species of bromeliads. The higher mobility of immature forms of beetles and dragonflies, and the availability of only one tank in Aechea lindenii, contrasting to several tanks in Vriesea friburgensis that help the suction of these immature, probably influenced the results, which indicated that the suction method should not replace the dismantling in the study of Culicidae and Chironomidae. This method can be useful to get immature forms of Scirtidae and Coenagrionidae in one-tank bromeliads.
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Han, M. Y., and J. S. Mun. "Particle behaviour consideration to maximize the settling capacity of rainwater storage tanks." Water Science and Technology 56, no. 11 (December 1, 2007): 73–79. http://dx.doi.org/10.2166/wst.2007.778.
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Design of a rainwater storage tank is mostly based on the mass balance of rainwater with respect to the tank, considering aspects such as rainfall runoff, water usage and overflow. So far, however, little information is available on the quality aspects of the stored rainwater, such as the behavior of particles, the effect of retention time of the water in the tank and possible influences of system configuration on water quality in the storage tank. In this study, we showed that the performance of rainwater storage tanks could be maximized by recognizing the importance of water quality improvement by sedimentation and the importance of the system configuration within the tank, as well as the efficient collection of runoff. The efficiency of removal of the particles was increased by there being a considerable distance between the inlet and the outlet in the rainwater storage tank. Furthermore, it is recommended that the effective water depth in a rainwater tank be designed to be more than 3 m and that the rainwater be drawn from as close to the water surface as possible by using a floating suction device. An operation method that increases the retention time by stopping rainwater supply when the turbidity of rainwater runoff is high will ensure low turbidity in the rainwater collected from the tank.
6
Lin, Wei Ting, Meng Hsiu Hsieh, Yuan Chieh Wu, and Chin Cheng Huang. "Response Spectrum Analysis of the Condensate Storage Tank in a Nuclear Power Plant." Applied Mechanics and Materials 284-287 (January 2013): 1421–25. http://dx.doi.org/10.4028/www.scientific.net/amm.284-287.1421.
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Following the nuclear power plant accident in Fukushima Japan, seismic capacity evaluation has become a crucial issue in combination building safety. Condensate storage tanks are designed to supplies water to the condensate transfer pumps, the control rod drive hydraulic system pumps, and the condenser makeup. A separate connection to the condensate storage tank is used to supply water for the high pressure coolant injection system, reactor core isolation cooling system, and core spray system pumps. A condensate storage tank is defined as a seismic class I structure, playing the important role of providing flow to the operational system and the required static head for the suction of the condensate transfer pumps and the normal supply pump. According to the latest nuclear safety requirements, soil structure interaction must be considered in all seismic analyses. This study aims to rebuild the computer model of condensate storage tanks in Taiwan using the SAP 2000 program in conjunction with the lumped mass stick model and to evaluate the soil structure interaction by employing the SASSI 2000 program. The differences between the results with the soil structure interaction and spring model are compared via natural frequency and response spectrum curves. This computer model enables engineers to rapidly evaluate the safety margin of condensate storage tank following the occurrence of earthquakes or tsunamis.
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Abdalla, Abdulmenam A., Ali K. Muftah, and Ahmed O. Amhamed. "THEORETICAL ANALYSIS AND GRAPHICAL REPRESENTATION OF THE SYSTEM CURVE FOR WATER PIPELINE CONNECTING ZAWIA DESALINATION PLANT WITH HARSHA TANKS." Scientific Journal of Applied Sciences of Sabratha University 2, no. 1 (April 25, 2019): 38–51. http://dx.doi.org/10.47891/sabujas.v2i1.38-51.
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The flow of water within a pipeline system causes loss of energy due to friction effects. To overcome these losses, energy is added to the water through the pump. So, the right pump selection is important for providing the required flow rate. The first step to select a right pump for any pipeline system is calculating the performance curve of piping system, which is a graphical representation of the energy required to move a given flow rate through a piping system and is used to identify the characteristics of the system's pump. For this purpose, the system curve for the water pipeline connecting the main reservoirs of Zawia desalination plant to the sub-tanks in Harsha has been evaluated and represented graphically in H-Q curve of the selected pump. This water pipeline network consists of sets of pipes connected in parallel and series with a total length of 5 km. The system NPSHA at different water levels in the suction tank at the maximum system flow rate of 800 (m3/hr) has been calculated to ensure avoiding cavitations problem in the selected pump.
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Stanley, C. D., G. A. Clark, E. E. Albregts, and F. S. Zazueta. "USE OF FIELD-LOCATED DRAINAGE LYSIMETERS FOR THE DETERMINATION OF STRAWBERRY WATER REQUIREMENTS." HortScience 25, no. 9 (September 1990): 1097d—1097. http://dx.doi.org/10.21273/hortsci.25.9.1097d.
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Sixteen field-located drainage lysimeters (each 60 cm wide, 2.44 m long, 60 cm deep) designed specifically for determination of water requirements for fruiting strawberry production (season - Oct to April) were installed in 1986. Each lysimeter was equipped with individual micro-irrigation and drainage collection systems automated for minimal management input. Initially, computer control (using a low-cost microcomputer) was used to continuously check switching-tensiometers located in each lysimeter and apply irrigation water as needed, A drainage suction (-10 MPa) was applied continuously to simulate field drainage conditions. Manually-installed lysimeter covers were used to protect the plots from interference from rainfall when needed, Initial irrigation application treatments were set at four levels of soil moisture tension controlled by tensiometers and were measured using flow meters for each lysimeter. This paper will discuss problems that were experienced with the initial setup (difficulty in measuring actual application amounts, tensiometer and computer control, elimination of rainfall interference, uniformity of irrigation application, and salinity in the rooting zone) and the modifications (pressurized reservoir tanks, construction of motorized rain-out shelter, micro-irrigation emitters used, and fertilization program) which have been made to overcome them,
9
Kim, Tae Ho, Kyong Uk Yang, Duck Jong Jang, and David W. Fredriksson. "The Submerging Characteristics of a Submersible Fish Cage System Operated by Compressed Air." Marine Technology Society Journal 44, no. 1 (January 1, 2010): 57–68. http://dx.doi.org/10.4031/mtsj.44.1.1.
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AbstractA numerical technique is developed to evaluate the submerging characteristics of a full-scale fish cage system operated by compressed air. The results of the numerical model are then compared to both physical model tests and in situ measurements. The cages incorporate the use of ballast tanks for fixed buoyancy and variable buoyancy control. The system is raised by injecting air from a compressor into the variable buoyancy ballast tanks. It is then lowered by releasing the air. The surfacing and submerging characteristics of the fish cage calculated with the numerical technique were similar to measurements obtained with the physical model and in situ tests. It was also found that the quantity of the inflow water is influenced more by the diameter of the suction pipe rather than by the changes in the pressure of compressed air. In addition, the changes in the diameter of the air evacuation pipe are considered to have a greater impact during the ascent rather than descent of the system. Other major factors that affect the vertical movement of the fish cage system operated by compressed air are the seawater flow rates and air flow rate supplied to the variable ballast system. It was concluded that the numerical method could be useful in analyzing various parameters required to optimize the surfacing and submerging characteristics of a fish cage system operated by compressed air.
10
Nagaoka, H., S. Ueda, and A. Miya. "Influence of bacterial extracellular polymers on the membrane separation activated sludge process." Water Science and Technology 34, no. 9 (November 1, 1996): 165–72. http://dx.doi.org/10.2166/wst.1996.0203.
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The objective of this study is to elucidate influence of bacterial extracellular polymers (EPS) on the performance of the submerged membrane separation activated sludge process (SMAS). Hollow fiber membrane modules were submerged in laboratory-scale reactors and the permeate was pulled out from the modules by suction pumps. Acetic acid was used as a carbon source and peptone or ammonium nitrogen was used as a nitrogen source in the substrate. The change of EPS amount both in the mixed liquor and on the membrane was measured and its influence on the permeability of the membrane was studied. EPS was accumulated in the aeration tanks and also on the membrane, which caused an increase of viscosity of the mixed liquor and an increase in the filtration resistance. Specific resistance of EPS was calculated to be of the order of 1016 to 1017 m kg−1. Change of the filtration resistance was explained as a function of viscosity of the mixed liquor, which is caused by rapid attachment of the suspended EPS and rapid detachment of the attached EPS. Detachment rate of the attached EPS was calculated to be nearly constant during the operation.
11
Rodionov, Valeriy A., Andrey V. Sverchkov, Alexey A. Rudnichenko, Fedor E. Mamontov, and Andrey A. Ermolaev. "Experimental and numerical studies of boat waterjets with increased seakeeping performance." Transactions of the Krylov State Research Centre 4, no. 394 (November 25, 2020): 31–42. http://dx.doi.org/10.24937/2542-2324-2020-4-394-31-42.
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Object and purpose of research. The object of the research is a fundamentally new waterjet, intended for installation on ships of increased seakeeping performance with discrete-variable bottom deadrise. The purpose of the research is to develop and test three waterjet designs that can be installed on vessels with large deadrise, operating in severe weather conditions.
Materials and methods. Experimental data of waterjet tests as a part of self-propelled models obtained in deep-water and cavitation test tanks of KSRC. Numerical simulation of the flow in water conduits of full-scale vessel taking into account the waterjet performance.
Main results. As a result of the performed experimental and computational studies, the characteristics of three waterjet designs with partial-pressure water inlets were obtained: two waterjets with isolated single-elbow water ducts and inlets on the bottom section with medium deadrise, "II"design; two waterjets with combined water duct and inlets on the bottom section with maximum deadrise and double jet, “X” design; single waterjet with bifurcating two-elbow water duct and a pair of water inlets on the bottom section with maximum deadrise, “Y” design.
Conclusion. The studies have shown that all the developed innovative waterjet designs are practically equal to conventional ones (or even better than them), and air suction creates a smooth, rather than a sharp force decrease on the impeller. The preference is given to a high-pressure water inlet with a bifurcated water inlet and a combined water conduit, because in intense waves, even if one of the inlets is aerated, the vessel will not abruptly lose speed or run off the course.
12
Troesch, S., A. Liénard, P. Molle, G. Merlin, and D. Esser. "Treatment of septage in sludge drying reed beds: a case study on pilot-scale beds." Water Science and Technology 60, no. 3 (July 1, 2009): 643–53. http://dx.doi.org/10.2166/wst.2009.389.
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French legislation requires the control of private on-site sanitation systems by local authorities. This will result in a large increase of the quantity of sludge from septic tanks to be treated. Nevertheless, large wastewater treatment plants are not systematically able to treat this sludge because they may have reached their nominal load or they are not so numerous in rural zone to avoid too long transportation. The study concerns both the feasibility of sludge reed beds devoted to the treatment of septage and the assessment of a simultaneous treatment with aerated sludge. The experiments have been carried out on eight pilot-scale drying reed beds (2 m2) planted with Phragmites australis. Two filtration layers of either vegetal compost or sand were tested. The study is focused on the commissioning period (first vegetative year) with a loading rate of 30 kg SS m−2 yr−1. According to these operational conditions, dewatering efficiencies reached approx. 30% DM during summer but less than 20%DM in winter for each filtration layer and sludge. High removal efficiencies, with an average of 96%, 92% and 89% for SS, COD and TKN respectively, were achieved with septage whereas they were lower for the mixture of aerated sludge and septage. The dewaterability of septage and its filtration behaviour were assessed by several parameters (Capillary Suction Time, bound water) which may be some interesting tools for an optimised loading strategy.
13
Zhang, Xi Xi, Yu Jing Jia, and Guang Zhen Cheng. "The Water Sump Cleaning Machine by Vacuum Suction." Applied Mechanics and Materials 201-202 (October 2012): 785–88. http://dx.doi.org/10.4028/www.scientific.net/amm.201-202.785.
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This article describes a vacuum water sump cleaning machine which is used to clean up coal mine water sump. Cleaning machine is composed of mechanical structure and electrical control devices. The parts of machine are made up of Walk the flatbed, storage mud tank, vacuum pumps, suction pipe, mud tubes, swing devices, control valves, suction pipe and pressure tracheal. When working, under the function of vacuum pumping, cleaning machine pulls out the vacuum from storage mud tank through the vacuum air feeder. As the vacuum level in the tank is increasing, under the function of atmospheric pressure outside world, the mud flows into the reservoir along the suction tube. When storage mud tank is full, vacuum pump automatically shut down. Turning off the vacuum valve and opening the pressure valve, the slime in the tank under the function of compressed air comes into the mine car through the row mud tube. The layout of this cleaning machine is reasonable, what is more, it is flexible and convenient to operate, so that it reduces the labor intensity significantly and improves the work efficiency of the clearance.
14
Cranfield, R. R. "Studies of Power Station Feed Pump Loss of Suction Pressure Incidents." Journal of Fluids Engineering 110, no. 4 (December 1, 1988): 453–61. http://dx.doi.org/10.1115/1.3243577.
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Open cycle feed systems featuring a deaerator followed by the boiler feed pumps have been subject to unexpected loss in net positive suction head during transient operation. This has been traced to separation at the deaerator storage tank drain and the formation of a steam/water interface in the downcomer to the pumps. The outflow at separation when the storage tank water is subcooled is generally much greater than the maximum suction flow corresponding to the unit rating, but when the tank water boils, as during transients, it may be very much less. Thus with a high suction flow in the boiling mode, the new interface may descend in the downcomer to result in feed pump cavitation, pressure imbalance, vapor locking, severe vibration, damage to the pump and an inability to maintain forward flow. Model tests have been conducted to establish the criterion for the separation in terms of the critical outflow for specific operating conditions as a function of geometric ratios involving tank-water depth and tank/downcomer dimensions. The data obtained although scattered are in general agreement with the data from actual plant and may be used to assess safe operating parameters.
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Herrera, Clara, Dirk Ponge, and Dierk Raabe. "Recrystallization during Annealing of a Cold Rolled Lean Duplex Stainless Steel." Materials Science Forum 715-716 (April 2012): 550. http://dx.doi.org/10.4028/www.scientific.net/msf.715-716.550.
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Duplex stainless steels (DSSs) are based on the Fe-Cr-Ni system and formed by ferrite (30-70%) and austenite. They have high tensile strength, good toughness and weldability and excellent corrosion resistance including stress-corrosion cracking and resistance to localized corrosion. The increase of the raw materials of the last years, there has been a motivation to develop new stainless steels with lower contents of nickel and molybdenum. Lean duplex stainless steels (LDSSs) are almost Mo free and nickel content lower than 4%. The lean duplex grades are expected to substitute not only 304/316 grades but also other duplex stainless steel grades. LDSSs are used for structural applications and for the less corrosion conditions such as liquor tanks and suction rolls. The aim of the present work was to study the kinetics of recovery and recrystallization of the lean duplex stainless steel 1.4362 during annealing treatment. The material was subjected to hot rolling and cold rolling of 70%, annealing treatment for different times at temperatures from 1000 to 1100°C and subsequently water quenched. Optical microscopy and electron back scattering diffraction (EBSD) were employed to study the evolution of the microstructure during the annealing treatment. After cold rolling austenite exhibited more strain hardening than ferrite. Consequently, the driving force of the austenite for recrystallization is higher. During annealing, recovery took place in ferrite, while the austenite remained nearly unrecovered until beginning of recrystallization. The layered grain morphology produced during cold rolling remained after the annealing treatment. The volume fraction of the phases did not show significant changes with the annealing time. Nevertheless, the volume fraction of austenite decline with an increasing of annealing temperature. After 60 seconds at 1100°C, annealing primary recrystallization had progressed in both phases, which show a bamboo-structure where the grain boundaries ran perpendicular to the phase boundaries. Grain growth progressed for longer annealing times. After 600 seconds, the bamboo-structure started to change for a more globular grain structure, pearl-structure. It continued and became more pronounced at longer annealing times. At lower temperatures, the recrystallization behavior is similar; however, the structure was refined. Recovery is favored by the high stacking fault energy of ferrite and the layered grain morphology. The lean duplex stainless steel 1.4362 shows a similar recrystallization kinetics compare with standard duplex stainless steels.
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Yamamoto, Kazuo, Masami Hiasa, Talat Mahmood, and Tomonori Matsuo. "Direct Solid-Liquid Separation Using Hollow Fiber Membrane in an Activated Sludge Aeration Tank." Water Science and Technology 21, no. 4-5 (April 1, 1989): 43–54. http://dx.doi.org/10.2166/wst.1989.0209.
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Direct membrane separation using hollow fibers was applied to wastewater treatment in an activated sludge process. A membrane module with a pore size of 0.1 micron was immersed in the aeration tank and treated water was filtered through the membrane by suction. Various operational modes were applied to investigate stable flux conditions as well as organic and nitrogen removal. The stable treatment with a detention time of 4 hours could be kept for about 120 days at a volumetric organic loading of 1.5 kg COD/(m3 day) using intermittent suction with a low pressure of 13 kPa (1.3 m as water head). The COD removal was higher than 95% and more than 90% of COD supplied was oxidized to keep MLSS almost constant in the reactor without sludge wastage, which suggests that total oxidation of influent biodegradable materials can be achieved in this system. Up to 60% of nitrogen could be denitrified by intermittent aeration. The critical organic loading was estimated as 3 to 4 kg COD/(m3 day) in order to keep both stable flux and aerobic condition. The clogging in the membrane was inevitable to some extent, however, the intermittent suction and low pressure operation without cleaning could prevent the unrecoverable clogging and dead end of operation.
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Zwierzchowski, Ryszard. "Improvement of operation of steam cushion system for sensible thermal energy storage." E3S Web of Conferences 116 (2019): 00107. http://dx.doi.org/10.1051/e3sconf/201911600107.
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The paper contains a method for improvement of operation of steam cushion system including its energy savings analyses, for a Thermal Energy Storage (TES) tank. Energy savings analyses were performed using operational data from selected Combined Heat and Power plants, which supply heat to large cities in Poland and are furnished with the TES. The role of the steam cushion system in the TES tank is to prevent the stored water against absorbing oxygen from atmospheric air. In the TES tank, which is a non-pressure tank, oxygen from atmospheric air could penetrate to the network water through the surge chamber and safety valves. The steam pressure under the roof is generated from technological steam injected under the roof. Energy savings in the steam cushion system are generated by using an appropriate technical solution for the upper orifice and suction pipe for circulation water, i.e., to make it movable through the use of pontoons. An isolating buffer layer is created at the top of the tank with very small convective and turbulent heat transport, which causes limited heat transfer from steam bed to the stored water in the tank. This results in heat flux of approximately 10% of the heat flux that occurs in the typical technical solution of the upper orifice and suction pipe for circulation water in the TES tank. This technology offers great opportunities to improve the operating conditions of District Heating System, cutting energy production costs and emissions of pollutants to the atmosphere.
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Isidro, Miguel, Pablo Trejo, and Marko López. "Soil water characteristic curve parameters of collapsible sand in Lambayeque, Peru." MATEC Web of Conferences 337 (2021): 01005. http://dx.doi.org/10.1051/matecconf/202133701005.
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Several structures are built on collapsible soils in the mining and petroleum industries and on civil sites. In order to analyze the stability of such structures, one must properly study the unsaturated soil behavior. Collapsible soils are frequent sand soil that are susceptible to a significant and sudden reduction in volume upon wetting. An important factor is matric suction, which es related to moisture content through the soil water Characteristic Curve (SWCC), the SWCC is obtained through a filter paper technique and provides a valuable relationship between suction and water content unique to soils. This measures the influence of parameters on the behavior of the structure of collapsible soil. Interactions between structure and soil must be properly evaluated as the bearing capacities of shallow and deep foundations are linked to properties of soil suction, moisture, and grade saturation. This work has experimentally measured the parameters of suction and moisture on the behavior of collapsible sands, where an oil storage tank will be built in the city of Lambayeque in Peru. Undisturbed soil specimens obtained from geotechnical exploration campaigns were used. The filter paper method used in this study was that proposed by models of Brooks-Corey and Van Genuchten. Results show consistent values near reported values from literature.
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Zhu, Xing Wang, Chun Xia Hu, Yan Li Lv, Chao Xin Wang, and Yu Gui Su. "The Performance Analysis on the 75°C Hot Water of the Air Source Heat Pump Using R134A." Advanced Materials Research 482-484 (February 2012): 758–62. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.758.
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In this paper the system of air-source heat pump water heater(ASHPWH) using R134A to get 75°C hot water is proposed. The experiments on the performance of ASHPWH are conducted in two typical conditions, one for 7°C dry bulb temperature and 6°C wet bulb temperature, the other for 20°C dry bulb temperature and 15°C wet bulb temperature. In addition the variations of the suction temperature, the exhaust temperature, the suction pressure, the exhaust pressure, the transient heat capacity, the input power and COPs with the changing of the hot water tank temperature are analyzed. The results show that 75°C hot water can be produced steadily and the COPs are 2.84 and 3.68 respectively in two different conditions, therefore the ASHPWH has good energy saving effect.
20
Big-Alabo, A., and C. Isaac. "Automatic water level control system using discretized components." Journal of Applied Sciences and Environmental Management 24, no. 10 (November 3, 2020): 1781–85. http://dx.doi.org/10.4314/jasem.v24i10.11.
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This study is based on the design of a portable automatic water level control switch that is capable of switching on the pump when the water level in the overhead tank goes low and switches it off as soon as the water level reaches a pre-determined level to prevent dry-run of the pump in case the level in the underground tank goes below the suction level. The water in the tank is measured by the conductive probes and displaced via the LED indicators. At maximum-set capacity the pump is de-energized to automatically switch off, thereby stopping the inflow of water into the tank. The design approach involves three major stages which are: the power supply unit, the sensing unit, and the motoring and relay unit. The uniqueness of this work is the use of discrete components such as transistors to achieve water level control. This approach is more economical, simpler and easier to implement than the sophisticated programmable logic controllers and computerized microprocessors.
Keywords: discrete components; conductive probes; sensors; relays; pump
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Li, Qing, Can Kang, Shuang Teng, and Mingyi Li. "Optimization of Tank Bottom Shape for Improving the Anti-Deposition Performance of a Prefabricated Pumping Station." Water 11, no. 3 (March 22, 2019): 602. http://dx.doi.org/10.3390/w11030602.
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High flexibility of prefabricated pumping stations in collecting and transporting storm water has been recognized. Nevertheless, flows inside such a complex system have rarely been reported. The present study aims to reveal water-sand flow characteristics in a prefabricated pumping station and to optimize geometric parameters of the tank to mitigate sand particle deposition. Five tank schemes, varying in the ratio of the diameter to the height of the tank bottom (D/L), were investigated. Flows in the pumping station were simulated using the computational fluid dynamics (CFD) technique. Test data were used to validate the numerical scheme. Three-dimensional water-sand flows in the pumping station were described. Underlying mechanisms of sand particle deposition were explained. The results indicate that the risk of deposition is high at the tank bottom side, close to the tank inlet. Both the tank bottom geometry and the inlet suction of the pump contribute to sand particle deposition. The averaged sand volume fraction at the pump inlet reaches its minimum at D/L = 3. Sand particle velocity at the pump inlet varies inversely with D/L. The highest intensity of the vortex at the pump inlet arises at D/L = 3. The best anti-deposition performance of the pumping station is attained at D/L = 3.
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Chen, L. C., S. S. Sung, W. W. Lin, D. J. Lee, C. Huang, R. S. Juang, and H. L. Chang. "Observations of blanket characteristics in full-scale floc blanket clarifiers." Water Science and Technology 47, no. 1 (January 1, 2003): 197–204. http://dx.doi.org/10.2166/wst.2003.0053.
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We monitored the changes in concentrations, zeta potentials, sizes and capillary suction times of the solids flocs in the clarified water from eight floc blanket clarifiers of PingTsan Water Works of Taiwan Water Supply Company with low (<10 NTU) and high (>100 NTU) turbidity raw water. For the former, one-stage coagulation-sedimentation treatment was adopted which yielded a rather unstable blanket. Complete washout was noticeable when the PACl dosage was insufficient. On the treatment of high-turbidity raw water, on the other hand, the Works adopted the combined treatment process, that is, the raw water was first coagulated and settled in a pre-sedimentation tank, afterwards, its effluent was coagulated again and clarified in the clarifiers. The resulting flocs could form a networked blanket that was relatively stable to the shock load in raw water turbidity.
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Quan, Zhen Hua, Gang Wang, Yao Hua Zhao, Yue Chao Deng, and Peng Xu. "Experimental Study of Solar-Air Composite Heat Pump System." Advanced Materials Research 827 (October 2013): 259–63. http://dx.doi.org/10.4028/www.scientific.net/amr.827.259.
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In the light of low efficiency of photovoltaic power generation and the problems of air source heat pumps application in the cold regions, this paper developed a composite evaporator and designed a new type of solar-air composite heat pump system, which was comprised of independently developed solar photovoltaic-thermal collector based on flat plate micro heat pipe and air source heat pump. The performances of heat pump system were studied experimentally, including water temperature of the heating tank, suction and discharge pressure, and performance of heat pump. When 73L water in the heating tank was heated by 1 HP heat pump from 15°C to 50°C at the ambient temperature of 5°C, the running time of dual heat source operation conditions was 5.14% shorter than that of separate air heat source operation conditions. Meanwhile, COP increased by 5.99%.
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HUANG, R. F., J. Y. WU, J. H. JENG, and R. C. CHEN. "Surface flow and vortex shedding of an impulsively started wing." Journal of Fluid Mechanics 441 (August 15, 2001): 265–92. http://dx.doi.org/10.1017/s002211200100489x.
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The particle tracking flow visualization method (PTFV) and particle image velocimetry (PIV) are used to obtain a clear picture of vortex evolution on the suction surface of an impulsively started NACA 0012 wing. The experiments are conducted in a towing water tank. The formation, evolution, and shedding of the vortex system on the suction surface are observed and analysed by streak pictures of particle images. Five characteristic vortex evolution regimes are identified in the parameter domain of angle of attack and chord Reynolds number. The pathline patterns, instantaneous streamlines, and vorticity of various vortex evolution processes are presented. Stable vortex shedding in the wake is eventually established after the initial period of complex vortex evolution on the suction surface of the wing. Various types of instabilities in the wake, e.g. instability wave, surface vortex shedding, and bluff-body vortex shedding, are found to correspond to different evolution processes of the surface flow. The shedding frequency of the vortices is correlated and compared with several conventional results. Topological critical points, separatrices, and alleyways are identified and discussed to elucidate the unsteady structure of the instantaneous streamline patterns. The topological rule for the number of singular points is verified.
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Park, Jung-Ho, In-Seob Park, So-Nam Yun, Young-Bog Ham, Pil-Woo Heo, and Sung-Cheol Jang. "A Collector of Dissolved Air Using Centrifugal Separation for Underwater Breathing." International Journal of Automation Technology 9, no. 1 (January 5, 2015): 76–82. http://dx.doi.org/10.20965/ijat.2015.p0076.
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This paper investigates a novel underwater breathing apparatus which has no air tank. Instead, it uses centrifugal separation to collect dissolved air. First, a prototype collector is proposed and fabricated. Then, the basic characteristics of various shape parameters are experimentally investigated using tap water to ascertain the optimal design. Next, to confirm the validity of the proposed mechanism, CFD analysis on collection ratio is done using the commercially available STAR-CD tool. After that, a suction device without an additional power source is developed to improve the air collection ratio. Finally, the redesigned collector is tested at different water temperatures, and the air collection results obtained are compared with the results of analysis.
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Gill, L. W., C. O'Suilleabhain, B. D. R. Misstear, P. Johnston, T. Patel, and N. O'Luanaigh. "Nitrogen loading on groundwater from the discharge of on-site domestic wastewater effluent into different subsoils in Ireland." Water Science and Technology 57, no. 12 (June 1, 2008): 1921–26. http://dx.doi.org/10.2166/wst.2008.336.
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The performance of six separate percolation areas has been intensively monitored to ascertain the attenuation effects of the unsaturated subsoil with respect to on-site wastewater effluent. Septic tank effluent on three sites and secondary treated effluent on the other three sites was discharged into subsoils of varying percolation values. Samples of the percolating effluent were taken using suction lysimeters installed to nominal depths of 0.3, 0.6 and 1.0 m below the invert of the percolation trenches. The results clearly showed that the development of a biomat across the percolation areas receiving secondary treated effluent was muted on these sites compared to the sites receiving septic tank effluent. Significant differences were found between the sites receiving septic tank and secondary treated effluent in terms of the potential nitrogen loading to groundwater. The average nitrogen loading after 1.0 m depth of unsaturated subsoil per capita equated to 5.5, 3.3 and 3.2 gTotal-N/d for the sites receiving secondary treated effluent compared to 4.2, 1.7 and 0.3 gTotal-N/d for the sites receiving septic tank effluent. The noticeably higher nitrogen loading on one of the septic tank sites corresponded to the effluent percolating through highly permeable subsoil that counteracted any significant denitrification.
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Lee, Kwon-Yeong, and Hyun-Gi Yoon. "An Innovative Passive Residual Heat Removal System of an Open-Pool Type Research Reactor with Pump Flywheel and Gravity Core Cooling Tank." Science and Technology of Nuclear Installations 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/150373.
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In an open-pool type research reactor, the primary cooling system can be designed to have a downward flow inside the core during normal operation because of the plate type fuel geometry. There is a flow inversion inside the core from the downward flow by the inertia force of the primary coolant to the upward flow by the natural circulation when the pump is turned off. To delay the flow inversion time, an innovative passive system with pump flywheel and GCCT is developed to remove the residual heat. Before the primary cooling pump starts up, the water level of the GCCT is the same as that of the reactor pool. During the primary cooling pump operation, the water in the GCCT is moved into the reactor pool because of the pump suction head. After the pump stops, the potential head generates a downward flow inside the core by moving the water from the reactor pool to the GCCT and removes the residual heat. When the water levels of the two pools are the same again, the core flow has an inversion of the flow direction, and natural circulation is developed through the flap valves.
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Dymarski, Czesław, Paweł Dymarski, and Jędrzej Żywicki. "Technology Concept of TLP Platform Towing and Installation in Waters with Depth of 60 m." Polish Maritime Research 24, s1 (April 25, 2017): 59–66. http://dx.doi.org/10.1515/pomr-2017-0022.
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Abstract The article is part of the design and research work conducted at the Gdansk University of Technology, Faculty of Ocean Engineering and Ship Technology, in cooperation with a number of other research centres, which concerns offshore wind farms planned to be built in the Polish zone of the Baltic sea in the next years. One of most difficult tasks in this project is building suitable foundations for each power unit consisting of a tower and a wind turbine mounted on its top. Since the water regions selected for building those wind farms have different depths, there was need to study different possible technical variants of this task, with the reference to both the foundation structures themselves, and the technology of their transport and setting, or anchoring. The article presents the technology of towing, from the shipyard to the setting place, and installation of the foundation having the form of a floating platform of TLP (Tension Leg Platform) type, anchored by tight chains to suction piles in the waters with depth of 60 m.
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Peng, Lu, Dong Jun Kim, and Hei Cheon Yang. "Vertical Mixed Jet Behavior of Orifice Nozzle." Advanced Materials Research 1070-1072 (December 2014): 1978–81. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.1978.
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The objective of this study is to experimentally investigate the mixed jet and oxygen transfer behavior of a vertical orifice nozzle. The experimental apparatus consisted of an electric motor-pump, an orifice nozzle, a circulation water tank, an air compressor, a high speed camera unit and controlling or measuring accessories. The entrainment ratio was calculated using the measured primary fluid flow rate and suction air flow rate with primary flow pressure. The visualization image of vertically injected air and mixed jet issuing from the orifice nozzle was analyzed qualitatively. As the air compressor pressure increases, the penetration length of mixed jet decreases and the mass ratio and dissolved oxygen concentration increase.
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Jablonská, Jana, Miroslav Mahdal, and Milada Kozubková. "Spectral Analysis of Pressure, Noise and Vibration Velocity Measurement in Cavitation." Measurement Science Review 17, no. 6 (December 20, 2017): 250–56. http://dx.doi.org/10.1515/msr-2017-0030.
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Abstract The article deals with experimental investigation of water cavitation in the convergent-divergent nozzle of rectangular cross-section. In practice, a quick and simple determination of cavitation is essential, especially if it is basic cavitation or cavitation generated additionally by the air being sucked. Air influences the formation, development and size of the cavity area in hydraulic elements. Removal or reduction of the cavity area is possible by structural changes of the element. In case of the cavitation with the suction air, it is necessary to find the source of the air and seal it. The pressure gradient, the flow, the oxygen content in the tank, and hence the air dissolved in the water, the air flow rate, the noise intensity and the vibration velocity on the nozzle wall were measured on laboratory equipment. From the selected measurements the frequency spectrum of the variation of the water flow of the cavity with cavitation without air saturation and with air saturation was compared and evaluated.
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Kane, Emily A., Hannah E. Cohen, William R. Hicks, Emily R. Mahoney, and Christopher D. Marshall. "Beyond Suction-Feeding Fishes: Identifying New Approaches to Performance Integration During Prey Capture in Aquatic Vertebrates." Integrative and Comparative Biology 59, no. 2 (June 21, 2019): 456–72. http://dx.doi.org/10.1093/icb/icz094.
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Abstract Organisms are composed of hierarchically arranged component parts that must work together to successfully achieve whole organism functions. In addition to integration among individual parts, some ecological demands require functional systems to work together in a type of inter-system performance integration. While performance can be measured by the ability to successfully accomplish ecologically relevant tasks, integration across performance traits can provide a deeper understanding of how these traits allow an organism to survive. The ability to move and the ability to consume food are essential to life, but during prey capture these two functions are typically integrated. Suction-feeding fishes have been used as a model of these interactions, but it is unclear how other ecologically relevant scenarios might reduce or change integration. To stimulate further research into these ideas, we highlight three contexts with the potential to result in changes in integration and underlying performance traits: (1) behavioral flexibility in aquatic feeding modes for capturing alternative prey types, (2) changes in the physical demands imposed by prey capture across environments, and (3) secondary adaptation for suction prey capture behaviors. These examples provide a broad scope of potential drivers of integration that are relevant to selection pressures experienced across vertebrate evolution. To demonstrate how these ideas can be applied and stimulate hypotheses, we provide observations from preliminary analyses of locally adapted populations of Trinidadian guppies (Poecilia reticulata) capturing prey using suction and biting feeding strategies and an Atlantic mudskipper (Periophthalmus barbarus) capturing prey above and below water. We also include a re-analysis of published data from two species of secondarily aquatic cetaceans, beluga whales (Delphinapterus leucas) and Pacific white-sided dolphins (Lagenorhynchus obliquidens), to examine the potential for secondary adaptation to affect integration in suction prey capture behaviors. Each of these examples support the broad importance of integration between locomotor and feeding performance but outline new ways that these relationships can be important when suction demands are reduced or altered. Future work in these areas will yield promising insights into vertebrate evolution and we hope to encourage further discussion on possible avenues of research on functional integration during prey capture.
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Asmara, Adelia Anju, Suphia Rahmawati, Andik Yulianto, Margita Rahayu Abay, Dilla Arlina, and Dhandhun Wacano. "A COMPREHENSIVE ASSESSMENT OF SEPTAGE MANAGEMENT IN BANTUL, YOGYAKARTA." INDONESIAN JOURNAL OF URBAN AND ENVIRONMENTAL TECHNOLOGY 4, no. 2 (April 6, 2021): 109. http://dx.doi.org/10.25105/urbanenvirotech.v4i2.7624.
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<p><strong>Aim:</strong> This study aims to assess the entire process of septage management comprising regulation, operational procedures, finance, community involvement, and water quality analysis to maximize the initial and hugest human fecal sludge treatment called Faecal Sludge Treatment Plant (IPLT) in Yogyakarta. <strong>Methodology and Results:</strong> The Modified EHRA (Environmental Health Risk Assessment) method was applied which focused only on wastewater treatment aspect. Several regulations including standard quality methods (SNI) were utilized and made a comparison between baseline rules and obtained results. Furthermore, quality assessment was accomplished by observation and interview. The results showed that the human sector needs to improve not only the amount of operators but also urgently put up protective personal equipment during the suction process. The dissemination of attractive information about sludge suction service done by PUPKP as a representation of the local government among the dwellers ought to upgrade a lot. Technologies employed which are carriage transportation and vacuum machine, are good enough. Contrarily, septage treatment plants require extra-effort to enhance it as most water quality parameters barely meet the standard quality. BOD, COD, ammonia, total coliform, oil and grease do not meet the third class of water quality (Government Regulation of Republic of Indonesia No. 82/2001). Subsequently, the effectiveness of each unit i.e. anaerobic tank and stabilization ponds are under 50% and the loading rate has a maximum capacity of 87.5m<sup>3</sup>/day, and 60m<sup>3</sup>/day minimum capacity. <strong>Conclusion, significance and impact of study:</strong> Therefore, almost all aspects of septage management in Bantul Yogyakarta are required to improve</p>
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de la Torre, T., B. Lesjean, A. Drews, and M. Kraume. "Monitoring of transparent exopolymer particles (TEP) in a membrane bioreactor (MBR) and correlation with other fouling indicators." Water Science and Technology 58, no. 10 (November 1, 2008): 1903–9. http://dx.doi.org/10.2166/wst.2008.752.
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The occurrence of Transparent Exopolymer Particles (TEP), an acidic fraction of polysaccharides, was monitored for more than six months in the activated sludge of three MBR units, and the relationship between TEP and other fouling indicators was studied. These compounds consist mainly of exopolysaccharides of a sticky nature, a characteristic which makes them a group of interesting substances in processes like sedimentation, flocculation and membrane fouling. The relationship between capillary suction time (CST) and polysaccharides (PS) was linear for the three tested sludges, although the correlation with TEP concentrations was stronger. A slight linear correlation of both TEP and PS was found with the critical flux (CF) measured with a small filtration test cell, which was submerged in the membrane tank to assess the filterability performance of the sludge in situ. However, the correlation CF-PS was clearer. The relationship between TEP, polysaccharides and sludge filterability highlights the potential of this parameter for the monitoring of membrane systems.
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Chang, D. J., S. H. Chen, C. Y. Chang, S. S. Lin, and J. S. Chang. "A new design of microfiltration system and application to wastewater treatment." Water Science and Technology 41, no. 10-11 (May 1, 2000): 181–88. http://dx.doi.org/10.2166/wst.2000.0638.
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A new microfiltration system with two sets of dead-end membrane cells and driven by a piston force system was designed in this study. In this system, suction of the filtrate was through the membrane in the reverse direction with a piston to backwash and reduce membrane fouling. In addition, after a few forward-reverse filtration cycles, the concentrated suspension of particles or solute on the retentate side was discharged into the stock tank under the cross flow condition. For maximizing the filtrate volume, it was found that the optimum times for forward and reverse filtration were 90 s and 3 s respectively, and the discharge frequency of retentate was 1 time per cycle. Moreover, it was also found that the filtrate volume increased with an increase in particle size and membrane pore size but decreased with an increase in feed concentration. Furthermore, an optimal filtrate volume existed on effecting the pressure drop. Finally, it could be used efficiently to treat and recycle the backwash wastewater from a rapid sand filter by a membrane with pore size of 0.1 and 0.22 μm.
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Cheng, Qin-Bo, Xi Chen, Dan-Dan Cheng, Yan-Yan Wu, and Yong-Yu Xie. "Improved Inverse Modeling by Separating Model Structural and Observational Errors." Water 10, no. 9 (August 28, 2018): 1151. http://dx.doi.org/10.3390/w10091151.
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A practical formal likelihood function (L) is developed to separate model structure errors and observation errors by the separation of correlated and uncorrelated model residuals. L overcomes the time-consuming problem of likelihood functions proposed by previous studies, and combines the Mean Square Error (MSE) and first-order Auto-Regression (AR(1)) models. For comparison of the effect of different error models, MSE, AR(1), and L are used as efficiency criteria to calibrate the three-dimensional variably saturated ground-water flow model (MF2K-VSF) based on the soil tank seepages of rainfall–runoff experiments. Results of L are nearly the same as those of AR(1) due to negligible observational errors. Although all calibrated models well mimic the seepage discharges, MF2K-VSF with MSE cannot capture the groundwater level and soil suction processes because of the considerable autocorrelation of model residuals owing to model inadequacies (e.g., neglect of the soil moisture hysteresis), which obviously violates the statistical assumption of MSE. By contrast, L accounts for the model structural errors and thus enhances the reliability of hydrological simulations.
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Sandbank, E., and G. Shelef. "Harvesting of Algae from High-Rate Ponds by Flocculation-Flotation." Water Science and Technology 19, no. 12 (December 1, 1987): 257–63. http://dx.doi.org/10.2166/wst.1987.0154.
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Microalgae grown in stabilization ponds and in high rate oxidation ponds (HROP) treating wastewater, were harvested by flocculation with aluminium sulfate and floated in a laboratory electro-flotation unit, where bubbles were produced electrolytically. It was shown that the higher the solids concentration, the lower is the air: solids ratio needed to achieve 90% algae removal. The simultaneous flocculation of suspended algae and release of bubbles while flocs grow, give equal suspended solids removal as the classical flush mixing flocculation followed by slow mixing-flotation stage. Air : solidsratios between 0.009 and 0.013 were sufficient for flocs flotation by dissolved air flotation (DAF) and electro flotation. Continuous flocculation-flotation in a DAF pilot plant unit showed that flush mixing can be replaced by injection of chemicals in-line provided a retention of 15 sec is given before the inflow to the flotation tank. Slow mixing could be eliminated altogether when bubbles were generated simultaneously with the flocculation stage. DAF was further simplified, replacing the air compressor used for pressuring air into water by a venturi suction at the under pressure side of the pump in the pressurised line. DAF in its simplified version is preferred for algae harvesting in fresh water algae cultures and in HROP systems, while it is recognized that electroflotation may be preferred in harvesting marine microalgae.
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Chiemchaisri, C., Y. K. Wong, T. Urase, and K. Yamamoto. "Organic Stabilization and Nitrogen Removal in Membrane Separation Bioreactor for Domestic Wastewater Treatment." Water Science and Technology 25, no. 10 (May 1, 1992): 231–40. http://dx.doi.org/10.2166/wst.1992.0251.
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In this study, organic stabilization and nitrogen removal were investigated using a household type hollow fiber membrane separation bioreactor of 6 2 1 volume. The process employed direct solid-liquid separation by hollow fiber membrane inside an activated sludge aeration tank. By providing highly turbulent conditions within the separation zone in conjunction with Jet aerating installation inside the membrane module, sludge accumulation on the membrane surface and inside the module can be reduced. Permeate flux obtained after 330 days of operation was 0.2 m/d under intermittent suction. High degree of organic stabilization was obtained in the system by operation without sludge wastage except for sampling purposes. Continuous and intermittent aeration modes were investigated in the study. The average effluent COD concentration of 20.8 and 16.5 mg/l were observed during continuous and intermittent aerating application respectively. Degree of nitrification depended upon DO concentration of mixed liquor during aeration period. Introduction of intermittent aeration enhanced total nitrogen removal up to 80% or more by simultaneous nitrification and denitrification, resulting in average of 4.9 mg/l of total nitrogen in the effluent. Increase in DO in aeration period from 1.5–2 mg/l to 4–5 mg/l improved percentage of nitrogen removal to more than 90%. Rejection of 4–6 log virus concentration by gel layer formed on the membrane surface was also observed.
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Gradetsky, V. G., M. M. Knyazkov, E. A. Semenov, and A. N. Sukhanov. "Dynamic Processes in Vacuum Contact Devices of Robots for Vertical Motion in the Water Environment." Mekhatronika, Avtomatizatsiya, Upravlenie 20, no. 7 (July 4, 2019): 417–21. http://dx.doi.org/10.17587/mau.20.417-421.
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The results of experimental investigation intended to improve movement conditions for pneumatic robots on vertical surfaces under water are discussed. Features of the movement of vacuum contact devices for the simulation of mathematical model of the vacuum contact device with surfaces under water are presented. The experimental studies made it possible to obtain additional data on the dynamics of attachment, to obtain transient processes for air-water flow through ejector and to correct the results obtained earlier. For the purpose of analytical study of dynamic processes occurring in the system of vacuum contact devices, and taking into account the complexity of the description of nonlinearities, linearized simplified models of the system "air ejector — contact device — water environment" were developed. Vacuum contact devices are designed to provide guaranteed contact with vertical surfaces, plane slopes or horizontal surfaces on which the underwater robot performs its movement, carrying out the prescribed technological tasks, for example, in dry wells of nuclear power plants, on the surfaces of ship hulls, on the surfaces of underwater structures. The models took into account the forces of adhesion to the surfaces under water — the forces from the pressure drop, the friction force, the contact and vacuum interaction, the elasticity of suction caps. As a result of the solution of the model problem, the values of mechanical parameters, as well as the values of vacuum and flow in the cavity of variable volume as functions of changing the gap between the end of the corrugated membrane and the surfaces are obtained explicitly. As a result of the study of dynamic processes occurring in simplified models of vacuum contact devices "air ejector — contact surface — water environment", the transient characteristics of the change in the operating forces and pressures over time, as well as the dependence of the normal and tangential components of the forces on the depth of immersion in water were obtained. The variants of the designs of vacuum contact devices with surfaces in the water environment are investigated, and the modernization of the laboratory test bench for testing vacuum contact devices under water is carried out.
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Drieu, Commander Michael, Ron MacKay, Flemming Hvidbak, Lieutenant Commander Peter Nourse, and David Cooper. "Latest Update of Tests and Improvements to Coast Guard Viscous Oil Pumping System (VOPS)1." International Oil Spill Conference Proceedings 2003, no. 1 (April 1, 2003): 447–52. http://dx.doi.org/10.7901/2169-3358-2003-1-447.
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ABSTRACT Over the past nine years, the U.S. Coast Guard has incorporated the Prevention Through People (PTP) philosophy as a “human factors” approach to learn how maritime operations can be regulated safer and be more efficient by evaluating training, management policies, operational procedures, and establishing partnerships with the maritime industry. One of the key elements of applying a PTP approach is identifying and incorporating lessons learned from major marine casualties and pollution incidents. Since 1997, the U.S. Coast Guard National Strike Force (NSF) has responded to three major oil spills involving foreign freight vessels grounding, which included the removal of highly viscous oil using various lightering equipment and systems. An informal workgroup consisting of the U.S. Coast Guard, U.S. Navy Supervisor of Salvage (NAVSUPSALV), and various representatives from oil pollution clean-up companies met at the following facilities: the Chevron Asphalt Facility in Edmonds, WA (September 1999), the Oil and Hazardous Materials Simulated Environmental Test Tank (OHMSETT) testing facility in Leonardo, New Jersey (November 1999 and March 2000), the Alaska Clean Seas (ACS) warehouse annex in Prudhoe Bay, AK (October 2000), and Cenac Towing Company facility in Houma, LA (May 2002). The group shared ideas and techniques, and tested different pumps and hose lengths with viscous oil. It was during the early tests that the first quantitative results showed just how efficient lubricated transport of heavy oil product could be, and broadened the knowledge of such methods to the entire industry. Although this technology had existed for many years in the oil production and handling industry, its use had never been investigated in a laboratory setting with regard to salvage response lightering systems. The lubrication of heavy oil product was first applied in the tests in the form of Annular Water Injection (AWI) by means of an, Annular Water Injection Flange (AWIF). This idea had been developed many years ago by the oil industry to improve oil output production, but was first applied to salvage response using the flange concept by the Frank Mohn Company of Norway. In concept, the flange applies water to the viscous product discharge of a pump by means of its unique geometry. The initial tests resulted in developing the use of AWI on the discharge side of the pump. This technique was further refined and applied to existing U.S. Coast Guard lightering systems in the form of the Viscous Oil Pumping System (VOPS) package, which has been issued to each of the three USCG Strike Teams of the National Strike Force (NSF). Latest improvements include using AWI on the suction side of the pump with hot water or steam. For this suction application, a different device used to deliver water lubrication was also tested concurrently with the discharge AWIF. Other significant improvements, which achieved one of the goals set in 2000, was to seek global partnership with other companies or agencies from other countries. In 2002, the Canadian Coast Guard formally joined the U.S. VOPS workgroup to form the Joint Viscous Oil Pumping System (JVOPS) Workgroup.
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Zhu, Fen Fen, Xiang Wei, Juan Juan Qi, Yi Qun Xiong, and Lu Yao Zhao. "Research on the Optimization of Beijing Municipal Sewage Plant Sludge Dewatering Reagent Cationic Polyacrylamide." Applied Mechanics and Materials 768 (June 2015): 526–31. http://dx.doi.org/10.4028/www.scientific.net/amm.768.526.
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With Chinese continuous improvement of the urbanization and industrialization level, water pollution has becoming more and more serious, and the by-product —sludge has caught the focus of public attention. The total amount of sewage sludge produced in Beijing in 2010 is about 3,700t/d (wet base), 2,500t/d of which is from the urban area and 1,200t/d is from country side. Such a large amount of sludge with abundant water brought great difficulties to the subsequent processing. However, the cost of sludge treatment amounts to almost half of the sewage plant running cost while the consumption of drug covered more than half of the sludge treatment expenditure. Another aspect is that the water content of the dewatered sewage sludge is not stable, because of the variation of inlet amount and quality. Without knowing the relationship between the characteristics of sewage sludge and conditioning reagent, the operator just try to add more reagent, which in the end increase the cost of sludge treatment. Meanwhile, cationic polyacrylamide (C-PAM) is currently the most widely used sludge conditioning reagent. This research is to find out the relationship between the characteristics of sewage sludge and adding dosage of CPAM, which can be the first step to discuss how to adjust the conditioning reagent according to sewage sludge with different characteristics.Polyacrylamide (PAM) of different cationic (15%,35%,45%,60%), molecular weight (8 million, 10million, 12million) and dosage (2‰,3‰,4‰,5‰,6‰) are under testing in the experiment considering the index of capillary suction time (CST).Experimental material is the sludge from digestion tank in one of Beijing sewage plants. According to the experiment, it was found that the 8million-10million molecular weight, 4‰-6‰ adding dosage perform the best.
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Ахмедова, Н. Р., and В. А. Наумов. "Features of hydraulic calculation of marine vacuum fish pumping units." MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), no. 3(53) (August 27, 2021): 262–66. http://dx.doi.org/10.37220/mit.2021.53.3.031.
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Цель статьи – модифицировать ранее разработанный метод гидравлического расчета вакуумной перекачивающей системы для течения в рыбонасосной установке, работающей на промысловом судне. Динамика откачивания и закачивания воздуха в буферную емкость не изменилась. Анализ экспериментальных данных показал, что гидравлические потери по длине трубопровода прямо пропорциональны величине массовой доли рыбы. В судовых условиях потери напора в местных гидравлических сопротивлениях могут иметь тот же порядок, что и потери по длине. В отличие от традиционных судовых систем течение жидкости в вакуумных рыбонасосных установках (ВРУ) является нестационарным из-за увеличения давления в буферной емкости, как на этапе всасывания, так и на этапе вытеснения. Что приводит к необходимости совместного решения уравнения Бернулли для нестационарных течений совместно с дифференциальными уравнениями для давления и объема жидкости в буферной емкости. Увеличение длины трубопровода или перепада высот приводит к снижению скорости движения водорыбной смеси и увеличению давления в буферной емкости. Как следствие, возрастает продолжительность цикла работы ВРУ и падает производительность. The purpose of the article is to modify a previously developed method of hydraulic calculation of a vacuum pumping system for a flow in a fish pump unit operating on a fishing vessel. The dynamics of pumping out and pumping air into the buffer tank did not change. Analysis of experimental data showed that hydraulic losses along the length of the pipeline are directly proportional to the value of the mass fraction of fish. In shipboard conditions, head losses in local hydraulic resistances can be of the same order as length losses. In contrast to traditional ship systems, the fluid flow in vacuum fish pumping units (VFP) is unsteady due to an increase in pressure in the buffer tank, both at the stage of suction and at the stage of displacement. This leads to the need of jointly solve the Bernoulli equation for unsteady flows together with differential equations for the pressure and volume of fluid in the buffer tank. An increase in the length of the pipeline or the height difference leads to a decrease in the speed of movement of the water-fish mixture and an increase in pressure in the buffer tank. As a result, the duration of the VFP operation cycle increases and the productivity decreases.
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Yang, Yang, Ling Zhou, Hongtao Zhou, Wanning Lv, Jian Wang, Weidong Shi, and Zhaoming He. "Optimal Design of Slit Impeller for Low Specific Speed Centrifugal Pump Based on Orthogonal Test." Journal of Marine Science and Engineering 9, no. 2 (January 26, 2021): 121. http://dx.doi.org/10.3390/jmse9020121.
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Marine centrifugal pumps are mostly used on board ship, for transferring liquid from one point to another. Based on the combination of orthogonal testing and numerical simulation, this paper optimizes the structure of a drainage trough for a typical low-specific speed centrifugal pump, determines the priority of the various geometric factors of the drainage trough on the pump performance, and obtains the optimal impeller drainage trough scheme. The influence of drainage tank structure on the internal flow of a low-specific speed centrifugal pump is also analyzed. First, based on the experimental validation of the initial model, it is determined that the numerical simulation method used in this paper is highly accurate in predicting the performance of low-specific speed centrifugal pumps. Secondly, based on the three factors and four levels of the impeller drainage trough in the orthogonal test, the orthogonal test plan is determined and the orthogonal test results are analyzed. This work found that slit diameter and slit width have a large impact on the performance of low-specific speed centrifugal pumps, while long and short vane lap lengths have less impact. Finally, we compared the internal flow distribution between the initial model and the optimized model, and found that the slit structure could effectively reduce the pressure difference between the suction side and the pressure side of the blade. By weakening the large-scale vortex in the flow path and reducing the hydraulic losses, the drainage trough impellers obtained based on orthogonal tests can significantly improve the hydraulic efficiency of low-specific speed centrifugal pumps.
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Barochkin, Yu E., S. D. Gorshenin, G. V. Leduhovsky, S. I. Shuvalov, and E. V. Zinovieva. "Calculation of static pressure field of liquid phase in the active zone of cavitation-jet deaerator." Vestnik IGEU, no. 6 (2019): 13–21. http://dx.doi.org/10.17588/2072-2672.2019.6.013-021.
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In cavitation-jet deaerators, the process of desorption of dissolved gases proceeds when boiling overheated water is directed in the form of a swirling vortex flow into the rarefaction zone. The removal of gases is carried out from the cavitation pocket formed along the flow axis. Such deaerators are characterized by relatively low efficiency. However, their small dimensions and the ability to work without supplying a heating coolant make them useful in cases where effective deaerators of other types cannot be applied by weight and size characteristics or temperature conditions. The expansion of the scope of practical application of cavitation-jet deaerators is hampered by the lack of appropriate mathematical description that would allow solving the problems of their schematic and constructive improvement. One of the main tasks in this case is to calculate the static pressure field of the liquid phase in the deaerator core. There are no ready-made solutions to this problem in the framework of previous studies. Thus, it is relevant from scientific and practical viewpoint to develop a simulation model of active zone of cavitation-jet deaerator, which allows determining the hydrodynamic characteristics of water flows and gas-vapor mixture when the elements, the mode of water supply and drainage evaporation change. Modeling the hydrodynamic situation in the active zone of cavitation-jet deaerator is based on the numerical solution for the Navier-Stokes equations and the continuity equation. These equations are written in the Reynolds decomposition. In this case, the standard k- turbulence model is used to obtain a preliminary solution, which is then refined during the transition to the SST turbulence model. The model is implemented by means of a software package for calculating fluid flows FlowVision. For the first time, a simulation model of the active zone of cavitation-jet deaerator was developed, which made it possible to determine the hydrodynamic characteristics of water flows and gas mixture when the elements design, the mode of water supply and drainage evaporation change. The field of static pressures of liquid phase in the active zone of cavitation-jet deaerator is determined. The results obtained do not contradict the published data describing the operation of cavitation-jet deaerators. In particular, they confirm an increase in the probability of deaerator overflow when gas exhaust is turned on. The results also prove the presence of a significant dependence of the deaeration efficiency on the hydraulic resistance of the evaporation suction tract. Based on the results obtained, a mathematical model of the deaeration process under the considered conditions can be developed.
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Narita, H., S. Mae, M. Nakawo, Y. Fujii, M. Yoshida, K. Kawada, and A. Higashi. "Ice-Coring At Mizuho Station, Antarctica, and Core Analyses: A Contribution from the Glaciological Research Program in East Dronning Maud Land, Antarctica." Annals of Glaciology 10 (1988): 213. http://dx.doi.org/10.1017/s0260305500004596.
Full textAbstract:
Between May 1983 and July 1984 glaciological parties of the 24th and 25th Japanese Antarctic Research Expeditions (JARE–24 and 25) carried out ice-core drilling using a thermal drill, down to 700.5 m depth at Mizuho Station (70°41'53"S, 44°19'54"E), as a part of the Glaciological Research Program in east Dronning Maud Land, Antarctica. The thermal drill, 3.9 m long and capable of taking a core 1.5 m long and 130 mm in diameter, is an improved version of a drill used by JARE–15 in 1975. The most important improvement was the monitoring system during drilling, for which a micro-computer was fitted in the drill. By using this system, such accidents as heater burn-out, tank overflow and failure of water suction would immediately be brought to our attention. The drilling speed was about 1.6 m/h, when the optimum output was 3.6 kW. The core recovery rate was above 99%. The core quality was good down to a depth of 80 m. Between 80 and 120 m, cracks were found at intervals of 0.15–0.5 m, and horizontal cracks were found continuously at intervals of 0.01 m or less. Immediately after the core was pulled, the stratigraphy was observed and bulk density was measured. A dust band, presumably volcanic particles, was seen at only 500.2 m depth during stratigraphic observation. The following analyses were carried out at Mizuho Station within a month of recovery: (1) Density determination by the hydrostatic method. (2) Measurement of total gas content. (3) Thin-section analyses, including observation of cracking around air bubbles and the crystalline texture, and ice-fabric studies. The 700.5 m core has been brought to Japan, and the following analyses are now under way: (1) Oxygen-isotope ratio. (2) Concentration of microparticles. (3) Electric conductivity. (4) Chemistry of soluble impurities.
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Narita, H., S. Mae, M. Nakawo, Y. Fujii, M. Yoshida, K. Kawada, and A. Higashi. "Ice-Coring At Mizuho Station, Antarctica, and Core Analyses: A Contribution from the Glaciological Research Program in East Dronning Maud Land, Antarctica." Annals of Glaciology 10 (1988): 213. http://dx.doi.org/10.3189/s0260305500004596.
Full textAbstract:
Between May 1983 and July 1984 glaciological parties of the 24th and 25th Japanese Antarctic Research Expeditions (JARE–24 and 25) carried out ice-core drilling using a thermal drill, down to 700.5 m depth at Mizuho Station (70°41'53"S, 44°19'54"E), as a part of the Glaciological Research Program in east Dronning Maud Land, Antarctica.The thermal drill, 3.9 m long and capable of taking a core 1.5 m long and 130 mm in diameter, is an improved version of a drill used by JARE–15 in 1975. The most important improvement was the monitoring system during drilling, for which a micro-computer was fitted in the drill. By using this system, such accidents as heater burn-out, tank overflow and failure of water suction would immediately be brought to our attention. The drilling speed was about 1.6 m/h, when the optimum output was 3.6 kW. The core recovery rate was above 99%.The core quality was good down to a depth of 80 m. Between 80 and 120 m, cracks were found at intervals of 0.15–0.5 m, and horizontal cracks were found continuously at intervals of 0.01 m or less.Immediately after the core was pulled, the stratigraphy was observed and bulk density was measured. A dust band, presumably volcanic particles, was seen at only 500.2 m depth during stratigraphic observation. The following analyses were carried out at Mizuho Station within a month of recovery: (1)Density determination by the hydrostatic method.(2)Measurement of total gas content.(3)Thin-section analyses, including observation of cracking around air bubbles and the crystalline texture, and ice-fabric studies.The 700.5 m core has been brought to Japan, and the following analyses are now under way: (1)Oxygen-isotope ratio.(2)Concentration of microparticles.(3)Electric conductivity.(4)Chemistry of soluble impurities.
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Ramsey, Richard, J. Greenough, and J. Breeze. "Noise-induced hearing loss in the military dental setting: a UK legislative perspective." BMJ Military Health 166, E (April 16, 2019): e53-e56. http://dx.doi.org/10.1136/jramc-2018-001150.
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IntroductionHealth professionals working in the dental environment are potentially at risk of noise-induced hearing loss (NIHL) due to the use of clinical and laboratory equipment. Workplaces engaging in the practice of dentistry within the UK are subject to legislation from the Control of Noise at Work (CNW) regulations 2005. Clinicians working in the military are at further increased risk of NIHL due to exposure from additional risk factors such as rifles or aircraft engines. To our knowledge, no authors have previously studied the noise levels experienced in a military dental setting or compared noise levels in a typical dental practice with current UK legislation.MethodMeasurements of noise levels experienced by a dentist, dental nurse and dental hygienist during a standard conservation procedure were assessed using wearable noise dose-badges. Furthermore, noise levels within a dental technician’s work space were also assessed. Noise levels produced by representative clinical and laboratory equipment were assessed and compared with CNW legislation.ResultsThe highest level for clinical equipment was produced by the suction apparatus while aspirating up a cup of water at 76 dB. For laboratory equipment, the lower exposure action value (LEAV) of 80 dB would be exceeded in 2.1 hours’ use of the trimmer, 3.6 hours’ use of the vibrating table and 9 min use of the airline.ConclusionsNoise levels experienced by clinicians within the dental surgery were well below the legislative LEAV thresholds for both peak and continuous noise. However, noise levels produced by laboratory equipment were far higher and there is clearly the potential for excessive noise exposure for dental professional in the everyday setting. Dental professionals responsible for dental laboratory settings must be familiar with the CNW regulations and measures put in place that control the inadvertent breach of legislation. Hearing protection must be mandated when using equipment that exceeds the LEAV and an educational programme is required to explain both their correct use and the rationale behind it. Methods of mitigating that risk further require exploration such as alternative methods of completing the tasks performed by the airline or reducing the noise generated by it, such as by reducing the supply pressure or using an alternative nozzle design.
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Sitranon, Jirawat, Charoenporn Lertsatitthanakorn, Pichai Namprakai, Naris Prathinthong, Taveewat Suparos, and Natthaphon Roonprasang. "Parametric Consideration of a Thermal Water Pump and Application for Agriculture." Journal of Solar Energy Engineering 137, no. 3 (June 1, 2015). http://dx.doi.org/10.1115/1.4029108.
Full textAbstract:
This research studied the effects of suction heads on the efficiency of a thermal water pump with steam. In order to save energy, the authors also studied the appropriate amount of air added to a steam working fluid. Cooling time was attempted to be shorten, direct contact cooling was employed. The system comprised feed water tank (FT), liquid piston tank (LT), heat tank (HT), storage tank (ST), well tank (WT), and check valve (CV). It was directly cooled by cooling water. Thermal energy input was supplied by an electric heater as a substitute of heat sources such as firewood. An operation of the pump consisted of five stages: heating, pumping, vapor-flow, cooling, and suction. In conclusion, increasing the suction head raised the pumping efficiency until the maximum was achieved. Using air in conjunction with the steam working fluid could lower the working temperature suitable for solar application. In addition, the simulation of a thermal pump with steam was merely presented. A good agreement between the test and the model was found. The larger pump size was selected to be constructed and tested in order to increase the pump efficiency. Agricultural application of the larger pump could obtain energy source from waste of firewood at no cost.
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Mascarenha, Márcia Maria dos Anjos, Manoel Porfírio Cordão Neto, and Tâmara Moraes Guimarães Silva. "Alternative Method for Analysing Hydromechanical Behaviour of Unsaturated Soils." Soils and Rocks, April 30, 2016, 29–39. http://dx.doi.org/10.28927/sr.391029.
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The suction-control techniques commonly used for laboratory studies of mechanical behaviour of unsaturated soils are much more time consuming than standard soil mechanics tests. In addition, few laboratories have the required apparatus for testing unsaturated soils. This paper proposes an alternative method of analysing hydromechanical behaviour of unsaturated soils with high-porosity. The method is divided in three tasks: 1) verification of the effect of void ratio changes on the water retention curve using filter paper; 2) determining water content changes by evaporation under the same test conditions; and 3) performing saturated and unsaturated consolidation tests. Unsaturated tests make use of samples that are less than 100% saturated and there is no suction control during the test. Therefore, only initial water content is known. Significant suction changes take place due to void closure and evaporation while testing. The results obtained using the proposed methodology showed the stress and suction path and enhance the understanding of the hydromechanical behaviour of unsaturated soils. The results also showed that analyses of water content alone cannot explain some unexpected results, such as: 20% initial water content samples present less deformation than 16% samples.
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"Food material cleaning device — has tank, pressurized water pipe, water bubbling means, water feed, suction pipe and jet port." Food Control 2, no. 4 (October 1991): 250. http://dx.doi.org/10.1016/0956-7135(91)90208-e.
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Rosmiati, Rosmiati, Tayeb Ibrahim, and Masykur Masykur. "ANALISA NPSH KERUSAKAN IMPELLER POMPA CETRIFUGAL CAIRAN CH3OH." Jurnal Mekanova: Mekanikal, Inovasi dan Teknologi 5, no. 2 (November 14, 2019). http://dx.doi.org/10.35308/jmkn.v5i2.1682.
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Liquid behavior is always influenced by the environment in the form of temperature and pressure (thermodynamics). This temperature and pressure affect the nature of the change in liquid phase into a mixture of water and steam or vice versa. Pumps that function to drain liquid also have temperature and pressure. If the pressure drops and the temperature stays or rises at the pump, the liquid phase changes to a liquid and vapor mixture phase. This phase change in the pump (suction side) is called the phenomenon capitation. Capitation in the pump will cause erosion of the impellers parts, resulting in decreased performance. This study analyzes the erosion of the casing and impeller at the 040-G01S pump of PT. KMI from the point of phenomenon of capitation. The phenomenon of capitation in pump suction empirically can be known if the required NPSHa value is less or equal to the available NPSHr value or NPSHa ≦ NPSHr. The NPSHa value is affected by the suction pump installation configuration. To find out the cause of erosion on the casing and impeller, it is necessary to calculate the NPSH (Net Positive Section Head) required and those available (manufacturers). The results of this study NPSHa value = 4.75 m and NPSHr value = 5 m) or NPSHa ≦ NPSHr at tank level <45%. So it is necessary to modify the installation of the pump suction side piping.