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Sample records for swimming pool heating

  1. Thermal analyses of solar swimming pool heating in Pakistan

    International Nuclear Information System (INIS)

    Ahmad, I.

    2011-01-01

    Hotels and swimming clubs in Pakistan pay huge gas bills for heating Swimming pools in winter. Winter days in most parts of Pakistan remain sunny and unglazed low cost solar collectors may be used to extend the swimming season. Installing the pool in a wind-protected area, which receives unobstructed solar radiation, may further reduce the size of the solar collectors required to heat the swimming pools. The pools should be covered with plastic sheet to eliminate evaporative heat losses and to prevent dust and tree leaves falling in the pool. The results of the thermal analysis show that in some parts of the country, a solar exposed pool can maintain comfortable temperature simply by using a plastic sheet on the pool surface. On the other hand, there are cities where solar collector array equal to twice the surface area of the pool is required to keep desired temperature in winter. (author)

  2. Mathematical modelling and simulation of the thermal performance of a solar heated indoor swimming pool

    Directory of Open Access Journals (Sweden)

    Mančić Marko V.

    2014-01-01

    Full Text Available Buildings with indoor swimming pools have a large energy footprint. The source of major energy loss is the swimming pool hall where air humidity is increased by evaporation from the pool water surface. This increases energy consumption for heating and ventilation of the pool hall, fresh water supply loss and heat demand for pool water heating. In this paper, a mathematical model of the swimming pool was made to assess energy demands of an indoor swimming pool building. The mathematical model of the swimming pool is used with the created multi-zone building model in TRNSYS software to determine pool hall energy demand and pool losses. Energy loss for pool water and pool hall heating and ventilation are analyzed for different target pool water and air temperatures. The simulation showed that pool water heating accounts for around 22%, whereas heating and ventilation of the pool hall for around 60% of the total pool hall heat demand. With a change of preset controller air and water temperatures in simulations, evaporation loss was in the range 46-54% of the total pool losses. A solar thermal sanitary hot water system was modelled and simulated to analyze it's potential for energy savings of the presented demand side model. The simulation showed that up to 87% of water heating demands could be met by the solar thermal system, while avoiding stagnation. [Projekat Ministarstva nauke Republike Srbije, br. III 42006: Research and development of energy and environmentally highly effective polygeneration systems based on using renewable energy sources

  3. Mathematical model development of heat and mass exchange processes in the outdoor swimming pool

    Directory of Open Access Journals (Sweden)

    M. V. Shaptala

    2014-12-01

    Full Text Available Purpose. Currently exploitation of outdoor swimming pools is often not cost-effective and, despite of their relevance, such pools are closed in large quantities. At this time there is no the whole mathematical model which would allow assessing qualitatively the effect of energy-saving measures. The aim of this work is to develop a mathematical model of heat and mass exchange processes for calculating basic heat and mass losses that occur during its exploitation. Methodology. The method for determination of heat and mass loses based on the theory of similarity criteria equations is used. Findings. The main types of heat and mass losses of outdoor pool were analyzed. The most significant types were allocated and mathematically described. Namely: by evaporation of water from the surface of the pool, by natural and forced convection, by radiation to the environment, heat consumption for water heating. Originality. The mathematical model of heat and mass exchange process of the outdoor swimming pool was developed, which allows calculating the basic heat and mass loses that occur during its exploitation. Practical value. The method of determining heat and mass loses of outdoor swimming pool as a software system was developed and implemented. It is based on the mathematical model proposed by the authors. This method can be used for the conceptual design of energy-efficient structures of outdoor pools, to assess their use of energy-intensive and selecting the optimum energy-saving measures. A further step in research in this area is the experimental validation of the method of calculation of heat losses in outdoor swimming pools with its use as an example the pool of Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan. The outdoor pool, with water heating- up from the boiler room of the university, is operated year-round.

  4. Swimming pool granuloma

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001357.htm Swimming pool granuloma To use the sharing features on this page, please enable JavaScript. A swimming pool granuloma is a long-term (chronic) skin ...

  5. Indoor heated swimming pools: the vulnerability of some infants to develop spinal asymmetries years later.

    Science.gov (United States)

    McMaster, Marianne E; Lee, A J; Burwell, R G

    2006-01-01

    Evidence reported in an earlier paper suggests that infants introduced to indoor heated swimming pools in the first year of life show an association with spinal asymmetries including progressive adolescent idiopathic scoliosis (AIS) and in normal subjects vertical spinous process asymmetry. Indoor heated swimming pools may contain a risk factor that predisposes some infants to develop such spinal asymmetries years later. What the risk factor(s) may be and its possible portal of entry into the infant's body are unknown and possibilities are examined. New teenage controls were obtained after mothers of AIS patients mentioned that they had taken their child to an infant swim class. In a further group of 18 normal teenagers introduced to an indoor heated swimming pool in the first year of life, 15 had vertical spinous process asymmetry. This prevalence of 83% of those at risk confirms our previous observation of vertical spinous process asymmetry in 61% of teenagers who were introduced to indoor heated swimming pools in the first year of life. Subject to confirmation of our observations consideration should be given to chemical risk factors, possible portals of entry, toxicology, environmental epigenomics and disease susceptibility to altered spinal development. If the risk factor is confirmed there may ultimately be a place for the prevention of AIS in some subjects.

  6. Heated indoor swimming pools, infants, and the pathogenesis of adolescent idiopathic scoliosis: a neurogenic hypothesis

    OpenAIRE

    McMaster Marianne E

    2011-01-01

    Abstract Background In a case-control study a statistically significant association was recorded between the introduction of infants to heated indoor swimming pools and the development of adolescent idiopathic scoliosis (AIS). In this paper, a neurogenic hypothesis is formulated to explain how toxins produced by chlorine in such pools may act deleteriously on the infant's immature central nervous system, comprising brain and spinal cord, to produce the deformity of AIS. Presentation of the hy...

  7. Swimming Pool Safety

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Safety & Prevention Immunizations All Around At Home At Play ... Español Text Size Email Print Share Swimming Pool Safety Page Content ​What is the best way to ...

  8. Comparison of swimming pools alternative passive and active heating systems based on renewable energy sources in Southern Europe

    International Nuclear Information System (INIS)

    Katsaprakakis, Dimitris Al.

    2015-01-01

    This article examines different passive and active heating systems for swimming pools. The passive systems introduced in this article are: * The swimming pools' enclosure. * The placement of floating insulating covers on the pools' surfaces whenever they are not used. The examined active systems in this article are: * A biomass heater. * A biomass heater and solar collectors combi-system. * Vertical geothermal heat exchangers (GHE) co-operating with geothermal heat pumps (GHP). The methodology employed for the introduced systems' evaluation is the arithmetic computational simulation of the swimming pools' annual heating, using annual time series of averaged hourly values for the available solar radiation and the calculated pools' thermal power demand (heating loads). The dimensioning of the active systems aims at the maximisation of the heating production from R.E.S. (renewable energy sources). and the optimisation of the corresponding investments' economic indexes. The examined systems are evaluated technically and economically versus fundamental criteria. It is proved that significant reduction of the heating loads is achieved with the introduced passive systems. The reduced swimming pools' heating loads can be successfully covered by the proposed R.E.S. active systems. The fossil fuels consumption is eliminated. The corresponding investments' payback periods can be lower than 5 years. - Highlights: • The passive solar systems reduce the swimming pools heating loads more than 90%. • The examined active heating system exhibit payback periods lower than 3.5 years. • The energy saving is maximised with a biomass heater – solar collectors system. • Single biomass heaters exhibits the shortest payback period. • GHE–GHP can be used in cases of low solar radiation and lack of biomass fuels

  9. Swimming Pools and Molluscum Contagiosum

    Science.gov (United States)

    ... Travelers’ Health: Smallpox & Other Orthopoxvirus-Associated Infections Poxvirus Swimming Pools Recommend on Facebook Tweet Share Compartir The ... often ask if molluscum virus can spread in swimming pools. There is also concern that it can ...

  10. Heated indoor swimming pools, infants, and the pathogenesis of adolescent idiopathic scoliosis: a neurogenic hypothesis

    Directory of Open Access Journals (Sweden)

    McMaster Marianne E

    2011-10-01

    Full Text Available Abstract Background In a case-control study a statistically significant association was recorded between the introduction of infants to heated indoor swimming pools and the development of adolescent idiopathic scoliosis (AIS. In this paper, a neurogenic hypothesis is formulated to explain how toxins produced by chlorine in such pools may act deleteriously on the infant's immature central nervous system, comprising brain and spinal cord, to produce the deformity of AIS. Presentation of the hypothesis Through vulnerability of the developing central nervous system to circulating toxins, and because of delayed epigenetic effects, the trunk deformity of AIS does not become evident until adolescence. In mature healthy swimmers using such pools, the circulating neurotoxins detected are chloroform, bromodichloromethane, dibromochloromethane, and bromoform. Cyanogen chloride and dichloroacetonitrile have also been detected. Testing the hypothesis In infants, the putative portals of entry to the blood could be dermal, oral, or respiratory; and entry of such circulating small molecules to the brain are via the blood-brain barrier, blood-cerebrospinal fluid barrier, and circumventricular organs. Barrier mechanisms of the developing brain differ from those of adult brain and have been linked to brain development. During the first 6 months of life cerebrospinal fluid contains higher concentrations of specific proteins relative to plasma, attributed to mechanisms continued from fetal brain development rather than immaturity. Implications of the hypothesis The hypothesis can be tested. If confirmed, there is potential to prevent some children from developing AIS.

  11. Heated indoor swimming pools, infants, and the pathogenesis of adolescent idiopathic scoliosis: a neurogenic hypothesis.

    Science.gov (United States)

    McMaster, Marianne E

    2011-10-05

    In a case-control study a statistically significant association was recorded between the introduction of infants to heated indoor swimming pools and the development of adolescent idiopathic scoliosis (AIS). In this paper, a neurogenic hypothesis is formulated to explain how toxins produced by chlorine in such pools may act deleteriously on the infant's immature central nervous system, comprising brain and spinal cord, to produce the deformity of AIS. Through vulnerability of the developing central nervous system to circulating toxins, and because of delayed epigenetic effects, the trunk deformity of AIS does not become evident until adolescence. In mature healthy swimmers using such pools, the circulating neurotoxins detected are chloroform, bromodichloromethane, dibromochloromethane, and bromoform. Cyanogen chloride and dichloroacetonitrile have also been detected. In infants, the putative portals of entry to the blood could be dermal, oral, or respiratory; and entry of such circulating small molecules to the brain are via the blood-brain barrier, blood-cerebrospinal fluid barrier, and circumventricular organs. Barrier mechanisms of the developing brain differ from those of adult brain and have been linked to brain development. During the first 6 months of life cerebrospinal fluid contains higher concentrations of specific proteins relative to plasma, attributed to mechanisms continued from fetal brain development rather than immaturity. The hypothesis can be tested. If confirmed, there is potential to prevent some children from developing AIS.

  12. Presentation of a calorigenic swimming-pool reactor and study of its use for urban heating, desalination of water, and other industrial applications

    International Nuclear Information System (INIS)

    Lerouge, B.

    The design characteristics of the heat-producing swimming pool reactor are discussed together with economic and technical considerations related to its utilization in the areas of district heating, process heat production, and desalination

  13. Grundfoss: Chlorination of Swimming Pools

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Hogan, John; Andreassen, Viggo

    1998-01-01

    Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools.......Grundfos asked for a model, describing the problem of mixing chemicals, being dosed into water systems, to be developed. The application of the model should be dedicated to dosing aqueous solution of chlorine into swimming pools....

  14. Performance of a swimming pool heating system by utilizing waste energy rejected from an ice rink with an energy storage tank

    International Nuclear Information System (INIS)

    Kuyumcu, Muhammed Enes; Tutumlu, Hakan; Yumrutaş, Recep

    2016-01-01

    Highlights: • An analytical model of the system, and a computational program were developed. • Transient behavior of the water in the buried energy storage tank was simulated. • Effects of various system parameters on the system performance were investigated. • Long period performance of the system was analyzed and obtained periodic condition. • Optimum ice rink size is determined for a semi-Olympic size swimming pool heating. - Abstract: This study deals with determining the long period performance of a swimming pool heating system by utilizing waste heat energy that is rejected from a chiller unit of ice rink and subsequently stored in an underground thermal energy storage (TES) tank. The system consists of an ice rink, a swimming pool, a spherical underground TES tank, a chiller and a heat pump. The ice rink and the swimming pool are both enclosed and located in Gaziantep, Turkey. An analytical model was developed to obtain the performance of the system using Duhamel’s superposition and similarity transformation techniques. A computational model written in MATLAB program based on the transient heat transfer is used to obtain the annual variation of the ice rink and the swimming pool energy requirements, the water temperature in the TES tank, COP, and optimum ice rink size depending on the different ground, TES tank, chiller, and heat pump characteristics. The results obtained from the analysis indicate that 6–7 years’ operational time span is necessary to obtain the annual periodic operation condition. In addition, an ice rink with a size of 475 m 2 gives the optimum performance of the system with a semi-Olympic size swimming pool (625 m 2 ).

  15. Dynamic simulation and thermo-economic analysis of a PhotoVoltaic/Thermal collector heating system for an indoor–outdoor swimming pool

    International Nuclear Information System (INIS)

    Buonomano, Annamaria; De Luca, Giuseppina; Figaj, Rafal Damian; Vanoli, Laura

    2015-01-01

    Highlights: • A PV/T heating system for indoor–outdoor swimming pools is proposed. • A comparison among some thermal pool models available in literature is carried out. • Dynamic simulations of the thermal behavior of the swimming-pools are performed. • PV/T thermal energy is used to heat the swimming pool and for DHW production. • Energy and economic parametric analyses of the proposed system are presented. - Abstract: This paper presents an analysis of an innovative renewable energy plant serving an existing indoor/outdoor swimming pool located in Naples. The proposed solar hybrid system is designed in order to balance the remarkable energy demand of the swimming pool facility and to ensure suitable comfort conditions for swimmers. With the aim to accomplish such goals, the dynamic thermal behavior of the swimming pool was analyzed as a function of the thermo-hygrometric conditions of the indoor space and on the meteorological conditions of the pool site. In order to properly design and size the proposed renewable energy system, different thermal pool loss formulations for the calculation of the swimming pool thermal balance, in indoor and outdoor regimes, are adopted. The solar hybrid system consists of a water cooled photovoltaic/thermal collectors plant (PV/T), designed to meet a part of the facility demands of electricity and heat. Electricity is completely utilized by the facility, while the produced thermal energy is primarily used to meet the pool thermal demand and secondarily for sanitary hot water scopes. In order to carry out dynamic simulations and sensitivity analyses, the system performance is designed and dynamically simulated in TRNSYS environment. The developed simulation model enables the calculation of both the indoor and outdoor swimming pool thermal losses and the overall energy and economic system performance. Such results are obtained as a function of the thermo-hygrometric conditions of the environment, of the occupants and the

  16. Ingestion of swimming pool water by recreational

    Data.gov (United States)

    U.S. Environmental Protection Agency — Swimming pool water ingestion data. This dataset is associated with the following publication: Dufour, A., L. Wymer, M. Magnuson, T. Behymer, and R. Cantu. Ingestion...

  17. [Chlorine concentrations in the air of indoor swimming pools and their effects on swimming pool workers].

    Science.gov (United States)

    Fernández-Luna, Álvaro; Burillo, Pablo; Felipe, José Luis; Gallardo, Leonor; Tamaral, Francisco Manuel

    2013-01-01

    To describe chlorine levels in the air of indoor swimming pools in Castilla-La Mancha (Spain) and relate them to other chemical parameters in the installation and to the health problems perceived by swimming pool workers. We analyzed 21 pools with chlorine as chemical treatment in Castilla-La Mancha. The iodometry method was applied to measure chlorine concentrations in the air. The concentrations of free and combined chlorine in water, pH and temperature were also evaluated. Health problems were surveyed in 230 swimming pool workers in these facilities. The mean chlorine level in the air of swimming pools was 4.3 ± 2.3mg/m(3). The pH values were within the legal limits. The temperature parameters did not comply with regulations in 17 of the 21 pools analyzed. In the pools where chlorine values in the air were above the legal regulations, a significantly higher percentage of swimming pool workers perceived eye irritation, dryness and irritation of skin, and ear problems. Chlorine values in the air of indoor swimming pools were higher than those reported in similar studies. Most of the facilities (85%) exceeded the concentration of 1.5mg/m(3) established as the limit for the risk of irritating effects. The concentration of chlorine in indoor swimming pool air has a direct effect on the self-perceived health problems of swimming pool workers. Copyright © 2012 SESPAS. Published by Elsevier Espana. All rights reserved.

  18. Virulent Naegleria fowleri in indoor swimming pool.

    Science.gov (United States)

    Kadlec, V; Skvárová, J; Cerva, L; Nebáznivá, D

    1980-01-01

    Naegleria fowleri was isolated from water during a hygienic inspection of a swimming pool in December 1977. This swimming pool was identified as a source of the infectious agent in the years 1962-1965, when a large outbreak of primary amoebic meningoencephalitis (PAME) occurred. First two strains of N. fowleri, pathogenic for white mice after intracerebral and intranasal inoculation, were isolated from water of outlet troughs, additional strains were then isolated from various places; particularly from a cavity in the damaged wall of the pool. The incubation temperature did not inhibit a simultaneous growth of amoebae of the genera Acanthamoeba, Flabellula, Hartmannella and Vahlkampfia in the primocultures. Epidemiological investigations did not reveal any new case of PAME in relation with the occurrence of pathogenic N. fowleri in the swimming pool.

  19. Swimming pool use and birth defect risk.

    Science.gov (United States)

    Agopian, A J; Lupo, Philip J; Canfield, Mark A; Mitchell, Laura E

    2013-09-01

    Swimming during pregnancy is recommended. However, the use of swimming pools is also associated with infection by water-borne pathogens and exposure to water disinfection byproducts, which are 2 mechanisms that are suspected to increase risk for birth defects. Thus, we evaluated the relationship between maternal swimming pool use during early pregnancy and risk for select birth defects in offspring. Data were evaluated for nonsyndromic cases with 1 of 16 types of birth defects (n = 191-1829) and controls (n = 6826) from the National Birth Defects Prevention Study delivered during 2000-2006. Logistic regression analyses were conducted separately for each birth defect type. Separate analyses were conducted to assess any pool use (yes vs no) and frequent use (5 or more occasions in 1 month) during the month before pregnancy through the third month of pregnancy. There was no significant positive association between any or frequent pool use and any of the types of birth defects, even after adjustment for several potential confounders (maternal race/ethnicity, age at delivery, education, body mass index, folic acid use, nulliparity, smoking, annual household income, surveillance center, and season of conception). Frequent pool use was significantly negatively associated with spina bifida (adjusted odds ratio, 0.68; 95% confidence interval, 0.47-0.99). Among offspring of women 20 years old or older, pool use was associated with gastroschisis (adjusted odds ratio, 1.3; 95% confidence interval, 1.0-1.8), although not significantly so. We observed little evidence suggesting teratogenic effects of swimming pool use. Because swimming is a common and suggested form of exercise during pregnancy, these results are reassuring. Copyright © 2013 Mosby, Inc. All rights reserved.

  20. ENERGY SAVING AT OPERATION OF OUTDOOR SWIMMING POOLS

    Directory of Open Access Journals (Sweden)

    V. F. Ivin

    2013-09-01

    Full Text Available Purpose. Energy saving is a major problem in modern power engineering and various energy-consuming devices. They include outdoor swimming pools. In order to maintain them in working condition, especially in winter period, it takes significant amount of thermal energy. Task of heat loss substantial decrease in open swimming pools is considered in the article (on DNURT example. Methodology. The method of determining the mass and heat loss on the basis of criteria equations of heat and mass transfer theory is used. Findings. Calculations of the actual DNURT pool heat loss for different seasons, as for natural convection both for air forced motion above the free water surface are performed. It is shown that for the adiabatic evaporation conditions of water from the pool in winter during blow-off with wind the heat loss can be up to 2 kW/m2 on surface. To reduce these losses it is offered to cover water surface in a pool with a special material with low thermal conductivity on the basis of porous polyethylene during the time when the pool is not used for other purposes. It is shown that the implementation of these standards will reduce the actual heat loss, at least 5-6 times. Originality. The solution of important environmental and energy problem thanks to reducing heat losses by the pool in different times of a year and correspondingly lower emissions of power generating enterprises. Practical value. It is shown that the coating surface of the pool with poorly heat-conducting and easy to install coating will let, at a minimum, to reduce the actual heat loss on 5-6 times and reduce the emissions of power plants generating energy for pool heating.

  1. Strategies for chemically healthy public swimming pools

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht

    Swimming pools are used around the world for recreational, rehabilitation and physical activity and therefore it is imperative that the water and air quality are safe for the health of the bathers. Chlorination is by far the most widely applied method to control pool water quality and to prevent...... spreading of pathogens between swimmers because of its residual disinfection effect. In addition to potential contamination of pathogenic microorganisms, swimming pool water is polluted by organic matter deposited from the bathers such as saliva, urine, sweat, hair and personal care products. Since chlorine...... is a strong oxidant it oxidizes the organic matter in the pool water and forms disinfection byproducts (DBPs). More than 100 different DBPs have been identified. Some of these have been found to be genotoxic and may pose an increased cancer risk for the bathers. The aim of this thesis was to give an overview...

  2. Swimming level of pupils from elementary schools with own swimming pool

    OpenAIRE

    Zálupská, Klára

    2012-01-01

    Title: Swimming level of pupils from primary school with private swimming pool. Work objectives: The aim is to identify assess level of swimming of pupils from first to ninth grade of primary school with a private pool in Chomutov district using continuous swimming test with regular swimming lessons, which is started in the first grade and persists until the ninth grade. The condition was organizing a school swimming lessons once a week for 45 minutes in all grades. Methodology: Swimming leve...

  3. [Infections transmitted in swimming pools].

    Science.gov (United States)

    von Suzani, C; Hazeghi, P

    1976-01-01

    Public swimmingpools can be the source of infections due to micro-organism such as mycobacterium balnei, adeno and enteroviruses, the virus of plantar warts and molluscum contagiosum, the TRIC-Agent of swimmingpool-conjonctivitis and pathogenic fungi. The transmission of trichomonas vaginalis is considered unlikely-Water of pools, supposed to present satisfactory qualities by standard controls, was found to contain pathogenic staphylococci and pseudomonas aeruginosa. Effective preventive measures include the continuous recording of the redox-potential of the water, limiting the number of visitors to pool design specifications, better desinfection of sanitary installations, regular maintenance of technical equipment including frequent backwashing of filters and exclusion of visitors with communicable disease.

  4. Isolation of Fungi in Swimming pools in Enugu, Nigeria | Mbata ...

    African Journals Online (AJOL)

    Background: It has been established that swimming pools contribute to the spread of fungal infections in susceptible hosts. Objectives: To isolate and identify fungi associated with swimming pools. Methods: A total of 147 samples from water and related areas of each swimming pool were tested for the presence of fungi.

  5. Infections Unlikely to be Spread Through Swimming Pools

    Science.gov (United States)

    ... please visit the Information for Aquatics Professionals page. Pinworm & Swimming Pinworm infections are rarely spread through the use of swimming pools. Pinworm infections occur when a person swallows pinworm eggs ...

  6. Mitigating the impact of swimming pools on domestic water demand

    African Journals Online (AJOL)

    demand. The study shows the need to reduce the impact of swimming pools. This could include: pool covers to reduce evaporation, the recycling of backwash water, the use of rainwater to top up swimming pools, water use surcharges and, finally, appropriate regulation and enforcement to prevent the use of municipal water ...

  7. System for reducing heat losses from indoor swimming pools by use of automatic covers. Final report, October 1, 1993--September 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    This final report is an account of the principal activities of Lof Energy Systems, Inc. in a two-year project funded by the Energy Related Inventions Program (ERIP) of the U.S. Department of Energy. The primary objective has been the development of a fully practical and economical system for saving energy in indoor swimming pools by use of motorized covers. The goal is wide-spread use of a fully developed product, in institutional swimming pools. Four major tasks, depicted in the accompanying Performance Schedule, have been completed, and one other has been initiated and its completion committed. Principal accomplishments have been the selection and improvement of cover materials and designs, lengthening and strengthening of reels and improvements in motorized components and their control, design and installation of pool covers in full scale demonstration and evaluation of fully developed commercial system, preparation and dissemination of manuals and reports, finalization of arrangements for Underwriters Laboratory certification of products, and final report preparation and submission. Of greatest significance has been the successful demonstration of the fully developed system and the verification and reporting by an energy consultant of the large savings resulting from pool cover use. Probably the best evidence of success of the DOE-ERIP project in advancing this invention to a commercial stage is its acceptance for sale by the Lincoln Equipment Company, a national distributor of swimming pool supplies and equipment. A copy of the relevant page in the Lincoln catalog is included in this report as Annex A. Representatives of that company now offer Tof motorized pool cover systems to their pool owner customers. In addition to the plans for securing UL certification the company expects to continue making design improvements that can increase system reliability, durability, and cost-effectiveness.

  8. Assessing Water Quality: Staphylococci as Microbial Indicators in Swimming Pools.

    Science.gov (United States)

    Rivera, Jo. Bechaida T.; Adera, Tilahun

    1991-01-01

    This study suggests that staphylococci may be the preferred microbial indicators of swimming pool water quality because these organisms met all criteria for best microbial indicators in terms of amount of recovery, resistance to disinfectants, and risk to bathers using water samples from nine swimming pools in Linn and Benton Counties, Oregon. (30…

  9. Some equipment for graphite research in swimming pool reactors

    International Nuclear Information System (INIS)

    Seguin, M.; Arragon, Ph.; Dupont, G.; Gentil, J.; Tanis, G.

    1964-01-01

    The irradiation devices described are used for research concerning reactors of the natural uranium type, moderated by graphite and cooled by carbon dioxide. The devices are generally designed for use in swimming pool reactors. The following points have been particularly studied: - maximum use of the irradiation volume, - use of the simplest technological solutions, - standardization of certain constituent parts. This standardization calls for precision machining and careful assembling; these requirements are also true when a relatively low irradiation temperature is required and the nuclear heating is pronounced. Finally, the design of these devices is suitable for the irradiation of other fissile or non-fissile materials. (authors) [fr

  10. The Ineffectiveness of Manual Treatment of Swimming Pools | Nnaji ...

    African Journals Online (AJOL)

    The University of Nigeria, Nsukka swimming pool was monitored for a period spanning about three months. The pool was constructed in 1961 and has been in operation since then except that many facilities including the treatment system are no longer functional forcing management to resort to treatment of the pool water ...

  11. Mitigating the impact of swimming pools on domestic water demand ...

    African Journals Online (AJOL)

    South Africa is a water-scarce country where the sustainable provision of water to its citizens is one of the most significant challenges faced. A recent study in Cape Town, South Africa, investigated the impact of residential swimming pools on household water demand and found that, on average, the presence of a swimming ...

  12. How to improve hygienic behaviour in holiday park swimming pools

    NARCIS (Netherlands)

    Stronks, I.; Keuten, M.G.A.

    2016-01-01

    Previous studies on contamination of swimming pool water showed that the hygienic behaviour of swimmers is the most important factor. The suggested hygienic behaviour is; having a pre-swim shower and using the toilet when nature calls. Knowing the importance of hygienic behaviour is one thing,

  13. Allegheny County Public Swimming Pool, Hot Tub, and Spa Inspections

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Public swimming pool, hot tub, and spa facilities are licensed and inspected once each year to assure proper water quality, sanitation, lifeguard coverage and...

  14. Health impact of disinfection by-products in swimming pools

    Directory of Open Access Journals (Sweden)

    Cristina M. Villanueva

    2012-12-01

    Full Text Available This article is focused on the epidemiological evidence on the health impacts related to disinfection by-products (DBPs in swimming pools, which is a chemical hazard generated as an undesired consequence to reduce the microbial pathogens. Specific DBPs are carcinogenic, fetotoxic and/or irritant to the airways according to experimental studies. Epidemiological evidence shows that swimming in pools during pregnancy is not associated with an increased risk of reproductive outcomes. An epidemiological study suggested an increased risk of bladder cancer with swimming pool attendance, although evidence is inconclusive. A higher prevalence of respiratory symptoms including asthma is found among swimming pool workers and elite swimmers, although the causality of this association is unclear. The body of evidence in children indicates that asthma is not increased by swimming pool attendance. Overall, the available knowledge suggests that the health benefits of swimming outweigh the potential health risks of chemical contamination. However, the positive effects of swimming should be enhanced by minimising potential risks.

  15. Study of Fungal Contamination of Indoor Public Swimming Pools

    OpenAIRE

    H Nanbakhsh; K Diba; K Hazarti

    2004-01-01

    Fungi are found in different environments with variable distribution patterns depending on various factors. The aim of this study was determination of fungal contaminants in public swimming pools in Uromia, Iran. The fungal contaminations of four indoor swimming pools were studied by using membrane filtration and swab sampling method. Samples were collected by a manual plastic pump, in a 200 ml sterilized bottle. All samples were collected within 2 hours and then transferred to the laboratory...

  16. The Ineffectiveness of Manual Treatment of Swimming Pools NNAJI ...

    African Journals Online (AJOL)

    Michael Horsfall

    period, the COD was above 80mg/l, the pH was between 6.2 and 7.1 as against 7.2 to 7.8 recommended by standards. The total plate count was within limits but ... strains of normal human flora have been found in chlorinated swimming pools ... mucus, saliva or skin in the swimming pool water or similar recreational water ...

  17. Large molten pool heat transfer

    International Nuclear Information System (INIS)

    1994-01-01

    This workshop on large molten pool heat transfer is composed of 5 sessions which titles are: feasibility of in-vessel core debris cooling; experiments on molten pool heat transfer; calculational efforts on molten pool convection; heat transfer to the surrounding water, experimental techniques; future experiments and ex-vessel studies (RASPLAV, TOLBIAC, BALI, SULTAN, CORVIS, VULCANO, CORINE programs)

  18. Study on water evaporation rate from indoor swimming pools

    Science.gov (United States)

    Rzeźnik, Ilona

    2017-11-01

    The air relative humidity in closed spaces of indoor swimming pools influences significantly on users thermal comfort and the stability of the building structure, so its preservation on suitable level is very important. For this purpose, buildings are equipped with HVAC systems which provide adequate level of humidity. The selection of devices and their technical parameters is made using the mathematical models of water evaporation rate in the unoccupied and occupied indoor swimming pool. In the literature, there are many papers describing this phenomena but the results differ from each other. The aim of the study was the experimental verification of published models of evaporation rate in the pool. The tests carried out on a laboratory scale, using model of indoor swimming pool, measuring 99cm/68cm/22cm. The model was equipped with water spray installation with six nozzles to simulate conditions during the use of the swimming pool. The measurements were made for conditions of sports pools (water temperature 24°C) and recreational swimming pool (water temperature 34°C). According to the recommendations the air temperature was about 2°C higher than water temperature, and the relative humidity ranged from 40% to 55%. Models Shah and Biasin & Krumm were characterized by the best fit to the results of measurements on a laboratory scale.

  19. Study on water evaporation rate from indoor swimming pools

    Directory of Open Access Journals (Sweden)

    Rzeźnik Ilona

    2017-01-01

    Full Text Available The air relative humidity in closed spaces of indoor swimming pools influences significantly on users thermal comfort and the stability of the building structure, so its preservation on suitable level is very important. For this purpose, buildings are equipped with HVAC systems which provide adequate level of humidity. The selection of devices and their technical parameters is made using the mathematical models of water evaporation rate in the unoccupied and occupied indoor swimming pool. In the literature, there are many papers describing this phenomena but the results differ from each other. The aim of the study was the experimental verification of published models of evaporation rate in the pool. The tests carried out on a laboratory scale, using model of indoor swimming pool, measuring 99cm/68cm/22cm. The model was equipped with water spray installation with six nozzles to simulate conditions during the use of the swimming pool. The measurements were made for conditions of sports pools (water temperature 24°C and recreational swimming pool (water temperature 34°C. According to the recommendations the air temperature was about 2°C higher than water temperature, and the relative humidity ranged from 40% to 55%. Models Shah and Biasin & Krumm were characterized by the best fit to the results of measurements on a laboratory scale.

  20. The solar heating system of the sport centre 'Guillamo Swimming Pool' in Sierre, Switzerland; Installation solaire thermique. Complexe sportif de la piscine de Guillamo - Rapport final

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This illustrated report for the Swiss Federal Office of Energy describes the refurbishment and the extension of the sport centre 'Guillamo Swimming Pool' in Sierre, Switzerland. The original building built in 1978 included three swimming pools (two indoor and one small outdoor). In 2005 a three-room fitness centre, a wellness centre and a bar were added to the compound and the old building and technical installations refurbished. At the same time a 591 m{sup 2} solar collector array was added. Unglazed selective solar absorbers were mounted on the 5{sup o} tilted flat roof. They insure at the same time the water tightness of the roof, a feature that lead to a significant cost reduction of the project. Before 2005 the natural gas consumption of the centre was 1.3 to 1.7 GWh/year. After the construction work the consumption was about 1.6 GWh, including a contribution of 0.06 GWh from the solar collectors. This last figure is disappointing. The reasons for this are mainly attributed by the authors to a very poor integration of the solar collectors into the conventional heat generation and distribution system, which do not enable the solar collectors to deliver the heat quantity they should. Changes should be made on the hydraulics of the whole system and on the control algorithms and settings.

  1. 21 CFR 1250.89 - Swimming pools.

    Science.gov (United States)

    2010-04-01

    ... equipped so as to provide complete circulation, replacement, and filtration of the water in the pool every six hours or less. Suitable means of chlorination and, if necessary, other treatment of the water shall be provided to maintain the residual chlorine in the pool water at not less than 0.4 part per...

  2. Sanitary Conditions of Public Swimming Pools in Amman, Jordan

    Directory of Open Access Journals (Sweden)

    Ashraf Abu Aqoulah

    2008-09-01

    Full Text Available This study was carried out in the summer of 2005 and investigated all of active public swimming pools (85 out of 93 in Amman, the capital of Jordan. The aim of this study was to find out if these swimming pools are in compliance with Jordanian Standards for Swimming Pools Water (JS 1562/2004. The pools were surveyed against the water microbial quality and other physicochemical parameters indicated in the standards. Two samples from each pool were collected for microbial analysis and pools monitoring were carried out during the afternoon of the weekends when the pools are most heavily used. The results indicated overall poor compliance with the standards. Compliance of the pools water to the microbial parameters was 56.5%, for residual chlorine 49.4%, for pH 87.7%, water temperature 48.8%, and bathing load 70.6%. The results also indicated that water microbial quality deteriorated with time. Multivariate analysis showed significant association of water contamination with time of sample collection, residual chlorine, water temperature and load of swimmers. The poor compliance was attributed to lack of proper disinfection, staff training, proper maintenance, and timely inspection.

  3. Cryptosporidium and Giardia in Swimming Pools, Atlanta, Georgia

    Centers for Disease Control (CDC) Podcasts

    2008-05-29

    In this podcast, Dan Rutz speaks with Dr. Joan Shields, a guest researcher with the Healthy Swimming Program at CDC, about an article in June 2008 issue of Emerging Infectious Diseases reporting on the results of a test of swimming pools in the greater Atlanta, Georgia area. Dr. Shields tested 160 pools in metro Atlanta last year for Cryptosporidium and Giardia. These germs cause most recreational water associated outbreaks.  Created: 5/29/2008 by Emerging Infectious Diseases.   Date Released: 5/29/2008.

  4. Swimming pools and intra-city climates: Influences on residential ...

    African Journals Online (AJOL)

    While determinants such as household income, regional climate, water price, property size and household occupancy have been comprehensively studied and modelled, other determinants such as swimming pools and intra-city climates have not. This study examines residential water consumption in the City of Cape Town ...

  5. Acanthamoeba species in Swimming Pools of Cairo, Egypt.

    Directory of Open Access Journals (Sweden)

    Ahmad Al-Herrawy

    2014-06-01

    Full Text Available The free-living amoebae Acanthamoeba spp. have been recognized as etiologic agents of amoebic encephalitis, keratitis, otitis, lung lesions and other skin infections mainly in immuno-compromised individuals. The purpose of this study is to detect the presence of Acanthamoeba in swimming pools in Egypt using a polymerase chain reaction (PCR method.Water samples were collected from 10 different swimming pools in Cairo, Egypt. Samples were cultured on non-nutrient agar for the detection of Acanthamoeba isolates that were confirmed by PCR amplification using genus specific primers. The molecularly confirmed Acanthamoeba isolates were morphologically identified to the species level.Members of genus Acanthamoeba were detected in 49.2% of the examined swimming-pool water samples. Morphologically, six Acanthamoeba species were isolated from the examined swimming pool water namely A. polyphaga, A.castellanii, A. rhysodes, A. mauritaniensis, A. royreba and A. triangularis. All the identified species of Acanthamoeba were molecularly confirmed to be related to the genus Acanthamoeba.The isolated species of Acanthamoeba could provoke variable degrees of infections to the swimmers. The culture method is cheaper and easier than PCR techniques that are faster for the detection of free-living amoebae.

  6. Potential risks of TiO2 and ZnO nanoparticles released from sunscreens into outdoor swimming pools

    International Nuclear Information System (INIS)

    Jeon, Soo-kyung; Kim, Eun-ju; Lee, Jaesang; Lee, Seunghak

    2016-01-01

    Highlights: • Nanoparticles from sunscreen products can be released into public pools. • Nanoparticles and organic ingredients can generate reactive oxygen species (ROS). • A negative impact of ROS should not be significant in swimming pool. - Abstract: The potential risks of nanoparticles (NPs) in sunscreens being released into swimming water were evaluated by a series of laboratory experiments simulating the fate and transport of NPs in outdoor swimming pools. NPs released from sunscreen-applied skin were estimated using pig skins covered with five different commercial sunscreens containing TiO 2 , ZnO, or both at various concentrations. Assuming that the swimming water treatment processes consisted of filtration, UV irradiation, heating, and chlorination, possible removal of the released NPs by each process was estimated. Generation of hydrogen peroxide (H 2 O 2 ) by the NPs under sunlight and after UV photochemical treatment were measured, and the H 2 O 2 concentration possibly present in the swimming pool was calculated based on some specific scenarios of operating an outdoor swimming pool. It was found that a significant amount of the NPs in sunscreens could be released into the swimming water, and accumulate during circulation through the treatment system. However, the concentration of H 2 O 2 possibly present in the swimming pool should be below the level at which an adverse effect to bathers is concerned.

  7. Potential risks of TiO{sub 2} and ZnO nanoparticles released from sunscreens into outdoor swimming pools

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Soo-kyung [Center for Water Resource Cycle, Green City Technology Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of); Energy Environment Policy and Technology, Green School, Korea University (KU)-Korea Institute of Science and Technology (KIST), Seoul 136-701 (Korea, Republic of); Kim, Eun-ju [Center for Water Resource Cycle, Green City Technology Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of); Lee, Jaesang [Energy Environment Policy and Technology, Green School, Korea University (KU)-Korea Institute of Science and Technology (KIST), Seoul 136-701 (Korea, Republic of); Civil, Environmental, and Architectural Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Lee, Seunghak, E-mail: seunglee@kist.re.kr [Center for Water Resource Cycle, Green City Technology Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of); Energy Environment Policy and Technology, Green School, Korea University (KU)-Korea Institute of Science and Technology (KIST), Seoul 136-701 (Korea, Republic of)

    2016-11-05

    Highlights: • Nanoparticles from sunscreen products can be released into public pools. • Nanoparticles and organic ingredients can generate reactive oxygen species (ROS). • A negative impact of ROS should not be significant in swimming pool. - Abstract: The potential risks of nanoparticles (NPs) in sunscreens being released into swimming water were evaluated by a series of laboratory experiments simulating the fate and transport of NPs in outdoor swimming pools. NPs released from sunscreen-applied skin were estimated using pig skins covered with five different commercial sunscreens containing TiO{sub 2}, ZnO, or both at various concentrations. Assuming that the swimming water treatment processes consisted of filtration, UV irradiation, heating, and chlorination, possible removal of the released NPs by each process was estimated. Generation of hydrogen peroxide (H{sub 2}O{sub 2}) by the NPs under sunlight and after UV photochemical treatment were measured, and the H{sub 2}O{sub 2} concentration possibly present in the swimming pool was calculated based on some specific scenarios of operating an outdoor swimming pool. It was found that a significant amount of the NPs in sunscreens could be released into the swimming water, and accumulate during circulation through the treatment system. However, the concentration of H{sub 2}O{sub 2} possibly present in the swimming pool should be below the level at which an adverse effect to bathers is concerned.

  8. Swimming pool attendance and respiratory symptoms and allergies among Dutch children

    NARCIS (Netherlands)

    Jacobs, J.H.; Fuertes, E.; Krop, E.J.M.; Spithoven, J.; Tromp, P.; Heederik, D.J.J.

    2012-01-01

    Objectives: To describe associations among swimming, respiratory health, allergen sensitisation and Clara cell protein 16 (CC16) levels in Dutch schoolchildren. Trichloramine levels in swimming pool air were determined to assess potential exposure levels. Methods: Respiratory health and pool

  9. Swimming pool attendance and respiratory symptoms and allergies among Dutch children

    NARCIS (Netherlands)

    Jacobs, J.H.; Fuertes, E.; Krop, E.J.M.; Spithoven, J.; Tromp, P.; Heederik, D.J.J.

    2012-01-01

    OBJECTIVES To describe associations among swimming, respiratory health, allergen sensitisation and Clara cell protein 16 (CC16) levels in Dutch schoolchildren. Trichloramine levels in swimming pool air were determined to assess potential exposure levels. METHODS Respiratory health and pool

  10. Indoor swimming pool attendance and respiratory and dermal health in schoolchildren: HITEA Catalonia.

    NARCIS (Netherlands)

    Font-Ribera, L.; Villanueva, C.M.; Gracia-Lavedan, E.; Borràs-Santos, A.; Kogevinas, M.; Zock, J.P.

    2014-01-01

    Background: Health benefits of swimming in pools may outweigh adverse health outcomes in children, but evidence from epidemiological studies is scarce or inconclusive for different health outcomes. We evaluated the association between indoor swimming pool attendance during childhood and respiratory

  11. Lip and tooth injuries at public swimming pools in Austria.

    Science.gov (United States)

    Lechner, Katharina; Connert, Thomas; Kühl, Sebastian; Filippi, Andreas

    2017-06-01

    There is an increased risk of orofacial injuries in swimming pool facilities. Nevertheless, only a few studies have addressed this issue. The aim of this study was to identify the frequency of lip and tooth injuries at public swimming pools in Austria. A further aim was to examine which gender and age groups were affected, where and why these injuries occurred, and whether pool attendants had sufficient knowledge of dental first-aid measures. A total of 764 pool attendants in Austria were contacted by telephone and 689 participated in the study (90.2%). The attendants were interviewed retrospectively about accident occurrences in 2014 by a standardized questionnaire. Responses to the provision of first aid and choice of storage medium for avulsed teeth were subsequently evaluated. The frequency of lip injuries was 19.0%, and tooth injuries were 11.3%. Male bathers (P < .05) and children under 12 years (P < .001) most frequently suffered injuries. The waterslide was the most common accident site. The most common cause of lip injuries was slipping on wet surfaces (39.0%), and for tooth injuries it was collisions with other persons or objects (each 28.1%). The pool attendants' responses were predominantly good or sufficient on first aid, with the exception of what storage medium to choose. Tooth rescue boxes were available in only 8.6% of all pool facilities. Orofacial injuries are a frequently occurring problem in swimming pool facilities. The pool attendants' knowledge on first-aid care of tooth injuries could still be improved. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Presence and select determinants of organophosphate flame retardants in public swimming pools

    Energy Technology Data Exchange (ETDEWEB)

    Teo, Tiffany L.L., E-mail: tiffany.teo@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Kensington NSW 2052 (Australia); Coleman, Heather M., E-mail: h.coleman@ulster.ac.uk [Nanotechnology and Integrated BioEngineering Centre, School of Engineering, University of Ulster, Jordanstown, County Antrim BT37 0QB, Northern Ireland (United Kingdom); Khan, Stuart J., E-mail: s.khan@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Kensington NSW 2052 (Australia)

    2016-11-01

    The occurrence of five organophosphate flame retardants (PFRs) consisting of tributyl phosphate (TNBP), tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1.3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) in swimming pools were investigated. Fifteen chlorinated public swimming pools were sampled, including indoor pools, outdoor pools and spa pools. The analyses were carried out using isotope dilution gas chromatography tandem mass spectrometry. All five PFRs were detected in swimming pool waters with concentrations ranging from 5–27 ng/L (TNBP), 7–293 ng/L (TCEP), 62–1180 ng/L (TCIPP), 10–670 ng/L (TDCIPP) and 8–132 ng/L (TPHP). The concentrations of PFRs were generally higher in indoor swimming pools compared to outdoor swimming pools. In municipal water supplies, used to fill the swimming pools in three of the sampling locations, the five PFRs were all below the limit of quantifications, eliminating this as the source. Potential leaching of PFRs from commonly used swimming equipment, including newly purchased kickboards and swimsuits was investigated. These experiments revealed that PFRs leached from swimsuits, and may be a source of PFRs in swimming pools. A quantitative risk assessment revealed that the health risk to PFRs via swimming pools was generally low and below commonly applied health risk benchmarks. - Highlights: • TNBP, TCEP, TCIPP, TDCIPP and TPHP were detected in chlorinated swimming pools. • PFRs were below the LOQ in fill water samples collected from 3 locations. • TCIPP was observed to have the highest concentrations in swimming pools. • PFRs are leaching from swimsuits and may be a source in swimming pools. • Health risks through oral and dermal exposure to PFRs in swimming pools were low.

  13. Spectacular energy technology: Panorama-Sauna Holzweiler. KfW funds indoor swimming pools as 'process heat'; Energetisch spektakulaer: Panorama-Sauna Holzweiler. KfW foerdert Schwimmbaeder als 'Prozesswaerme'

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, Rolf

    2008-11-15

    The ''Panorama-Sauna'' at Grafschaft is a big indoor swimming pool and Sauna centre in a rural region not far from Cologne and Koblenz. The charm of this spectacular solar project is in its minimalism. Conventional solar thermal power systems, in contrast, tend to be complex and prone to failure. (orig.)

  14. Swimming Lessons: Learning, New Materialisms, Posthumanism, and Post Qualitative Research Emerge through a Pool Poem

    Science.gov (United States)

    McKnight, Lucinda

    2016-01-01

    This article shifts from the formal learning spaces of school and university to an Australian public swimming pool to playfully engage some of the dilemmas that recent theory poses for curriculum studies. The article enacts multiple diffractions (Barad, 2007) as theory becomes swimming and swimming becomes theory, and ideas and movements are…

  15. Abandoning nature: swimming pools and clean, healthy recreation in Hamilton, Ontario, c. 1930s-1950s.

    Science.gov (United States)

    Bouchier, Nancy B; Cruikshank, Ken

    2011-01-01

    Municipal swimming pools arose as a technological fix for an urban public health and recreation crisis in Hamilton when its bay became a polluted sink for residential and industrial wastes. Until World War II, city leaders and medical authorities believed that they could identify, delineate, and construct safe natural swimming areas along the bay's shore, supplemented by a few public artificial swimming pools. After the war, the pollution situation worsened. For those who couldn't travel to cleaner lakeshores elsewhere, local authorities created swimming pools, thus abandoning the natural waters of the bay to the "constructive power of the profit motive".

  16. Survey of bacterial contamination of environment of swimming pools in Yazd city, in 2013

    Directory of Open Access Journals (Sweden)

    Hossein Jafari Mansoorian

    2015-09-01

    Full Text Available Background: Infections are readily transmitted as a result of bacterial contamination of swimming pools. Therefore, hygiene and preventing the contamination of swimming pools is of particular importance. The objective of this study was to determine the amount of bacterial contamination in indoor pools of Yazd in 2013. Methods: In this descriptive and analytical study, all indoor swimming pools of Yazd (12 pools were evaluated during the spring and summer of 2013, in terms of bacterial contamination. In order to determine contamination, a sterile cotton swab was used for sampling. On average, 45 samples were taken from different surfaces in each pool (shower, dressing room, sitting places in sauna, platforms and around the pool. In total, about 540 samples from all pools were tested for bacterial contamination. Results: The results show that from 540 samples, bacterial contamination was observed in about 93 samples (17.22%; and was seen more in showers, edges of the pool and jacuzzis, and the slippers used in swimming pools. The most important isolated bacteria types were E. coli, Actinobacteria, Pseudomonas alcaligenes, Pseudomonas aeruginosa and Klebsiella pneumonia. Conclusion: The results indicate the presence of bacterial contamination on the surface of these places. It is recommended that health authorities should pay more attention to cleaning and disinfecting surfaces around the pool, showers, dressing rooms etc, to prevent infectious disease transfer as a result of contact with contaminated swimming pool surfaces.

  17. Semi-Automatic Detection of Swimming Pools from Aerial High-Resolution Images and LIDAR Data

    Directory of Open Access Journals (Sweden)

    Borja Rodríguez-Cuenca

    2014-03-01

    Full Text Available Bodies of water, particularly swimming pools, are land covers of high interest. Their maintenance involves energy costs that authorities must take into consideration. In addition, swimming pools are important water sources for firefighting. However, they also provide a habitat for mosquitoes to breed, potentially posing a serious health threat of mosquito-borne disease. This paper presents a novel semi-automatic method of detecting swimming pools in urban environments from aerial images and LIDAR data. A new index for detecting swimming pools is presented (Normalized Difference Swimming Pools Index that is combined with three other decision indices using the Dempster–Shafer theory to determine the locations of swimming pools. The proposed method was tested in an urban area of the city of Alcalá de Henares in Madrid, Spain. The method detected all existing swimming pools in the studied area with an overall accuracy of 99.86%, similar to the results obtained by support vector machines (SVM supervised classification.

  18. Occurrence and human exposure of parabens and their chlorinated derivatives in swimming pools.

    Science.gov (United States)

    Li, Wenhui; Shi, Yali; Gao, Lihong; Liu, Jiemin; Cai, Yaqi

    2015-11-01

    As an emerging group of endocrine-disrupting chemicals, parabens have attracted growing attention due to their potential effects on human health. In the present study, the occurrence and distribution of eight parabens, four chlorinated parabens, and their common hydrolysis product, p-hydroxybenzoic acid (PHBA), were investigated in 39 swimming pools in Beijing, China. Methyl paraben and propyl paraben were the predominant compounds in swimming pools, accounting for 91.2 % of the total parabens. It is noteworthy that octyl paraben, a paraben with longer chain, was firstly detected in this study. There were several factors affecting the levels of parabens among the 39 swimming pools. The concentrations of parabens and chlorinated derivatives detected in indoor pools (144 ng L(-1)) were roughly 20-fold higher than those in outdoor pools (6.78 ng L(-1)). Hotel pools appear to present higher level of target compounds (361 ng L(-1)) than that in health club (228 ng L(-1)), municipal (130 ng L(-1)), school (75.6 ng L(-1)), and community pools (63.0 ng L(-1)). Moreover, the level of these compounds in pools during weekends (174 ng L(-1)) was much higher than that during weekdays (52.3 ng L(-1)). The dynamics of target compounds were also investigated to provide a general trend of the level of parabens in a school indoor swimming pool during a 14-week period. Human exposure assessment was conducted to estimate the potential risk of exposure to parabens and their chlorinated derivatives in swimming pools. Considering the total exposure dose of multiple parabens, human exposure to parabens from the water of swimming pools is negligible. However, the threat of these parabens to children in swimming pool should be concerned.

  19. Effect of pool length on blood lactate, heart rate, and velocity in swimming.

    Science.gov (United States)

    Keskinen, O P; Keskinen, K L; Mero, A A

    2007-05-01

    Exercise testing in water has been used to follow the progression of conditioning during regular training in swimmers. The present study examined the effects of pool length in eleven male swimmers on a set of 5 x 200-m freestyle swims with increasing speed from submaximal to maximal. Mean velocity of swimming, blood lactate and heart rate were examined in both 25-m and 50-m pools. Turning benefit as a marker for turning skill was measured separately by a underwater video system (speed difference between pre- and post-turning) during short all-out swims. Maximum force during swimming was measured in tethered swimming and explosive strength of leg extensor muscles was evaluated by a counter movement jump. The significantly higher (p=0.033 - 0.000) blood lactate values for the 50-m pool as compared to the 25-m pool were found at each point of swimming velocity versus blood lactate curve. The highest post-test lactate level was 7.36 +/- 1.47 mmol x l (-1) in the short course and 8.24 +/- 1.55 mmol x l (-1) (p=0.033) in the long course. The maximum swimming velocity was significantly greater (4.5 %) in the 25-m pool swimming (1.38 +/- 0.11 m x s (-1) vs. 1.32 +/- 0.12 m x s (-1); p=0.000). The heart rate values were significantly (p=0.020 - 0.000) lower in the short course than in the long course at all points of submaximal velocity with a mean difference of 7.3 +/- 0.7 bpm. Heart rate was equal (172 +/- 14 vs. 172 +/- 14 bpm) after the maximum swims in both short and long course. The turning benefit in the short maximum swim was 0.12 +/- 0.05 m x s (-1) (8.1 +/- 3.2 %), correlating positively with the difference in maximal swimming velocity between the short and long-pool swims (r = 0.59; p = 0.029), with the maximum force during tethered swimming (r=0.75; p=0.004) and with the vertical jumping height in the counter movement jump (r=0.55; p=0.039). We conclude that the pool length has a strong effect on blood lactate concentration and heart rate with greater swimming

  20. Titanium distribution in swimming pool water is dominated by dissolved species

    International Nuclear Information System (INIS)

    David Holbrook, R.; Motabar, Donna; Quiñones, Oscar; Stanford, Benjamin; Vanderford, Brett; Moss, Donna

    2013-01-01

    The increased use of titanium dioxide nanoparticles (nano-TiO 2 ) in consumer products such as sunscreen has raised concerns about their possible risk to human and environmental health. In this work, we report the occurrence, size fractionation and behavior of titanium (Ti) in a children's swimming pool. Size-fractionated samples were analyzed for Ti using ICP-MS. Total titanium concentrations ([Ti]) in the pool water ranged between 21 μg/L and 60 μg/L and increased throughout the 101-day sampling period while [Ti] in tap water remained relatively constant. The majority of [Ti] was found in the dissolved phase (<1 kDa), with only a minor fraction of total [Ti] being considered either particulate or microparticulate. Simple models suggest that evaporation may account for the observed variation in [Ti], while sunscreen may be a relevant source of particulate and microparticule Ti. Compared to diet, incidental ingestion of nano-Ti from swimming pool water is minimal. -- Highlights: •Total titanium concentrations in unfiltered swimming pool water ranged between 21 and 60 μg/L. •Evaporation of the swimming pool water is suspected of causing a temporal increase in [Ti]. •The vast majority of Ti is found in the dissolved phase (<1 kD). •Swimming pools are not a significant Ti source for human exposure via ingestion. -- In children's swimming pool water, the majority of titanium is found in the dissolved phase

  1. THE USE OF MEMBRANE TECHNIQUES IN SWIMMING POOL WATER TREATMENT

    Directory of Open Access Journals (Sweden)

    Edyta Łaskawiec

    2017-07-01

    Full Text Available The paper has determined the suitability of membrane processes (UF ultrafiltration, UF, and nanofiltration, NF for the purification of waste streams, so-called backwash water, obtained from washing filtration beds in a swimming pool water system. The backwash water samples were taken from the circuits located in two indoor facilities with a different purpose of the basins. Moreover, the samples were characterized by varying quality, as described by selected physicochemical parameters (such as turbidity and ultraviolet absorbance UV254. Commercial membranes were used for the tests. The transport-separation properties of the membranes were determined based on the volumetric flux of the permeate. In addition, backwash water samples before and after the membrane process were subjected to toxicological assessment using the Microtox® screening test. The performed processes contributed to a significant reduction in turbidity and the value of UV254 ultraviolet absorbance, both in the ultrafiltration and nanofiltration processes. Whereas, significant differences in transport properties were noted within individual processes. A great influence of backwash water quality, including physicochemical parameters, on the course and results of the membrane filtration processes was demonstrated. In all of the nanofiltration cycles carried out, the removal of the toxic properties of the backwash water with respect to bacteria in the Microtox® test was found. Nevertheless, samples with high values of resultant physicochemical parameters after the ultrafiltration process were still characterized by high toxicity. Pressure membrane processes show high effectiveness in the removal of contaminants from backwash water. However, it is necessary to introduce supporting processes aimed at reducing membrane pore blocking by deposits and organic compounds, and in the case of ultrafiltration, assuring the safety of the purified stream in terms of the toxicological effect.

  2. Trihalomethane exposures in indoor swimming pools: a level III fugacity model.

    Science.gov (United States)

    Dyck, Roberta; Sadiq, Rehan; Rodriguez, Manuel J; Simard, Sabrina; Tardif, Robert

    2011-10-15

    The potential for generation of disinfection byproducts (DBPs) in swimming pools is high due to the concentrations of chlorine required to maintain adequate disinfection, and the presence of organics introduced by the swimmers. Health Canada set guidelines for trihalomethanes (THMs) in drinking water; however, no such guideline exists for swimming pool waters. Exposure occurs through ingestion, inhalation and dermal contact in swimming pools. In this research, a multimedia model is developed to evaluate exposure concentrations of THMs in the air and water of an indoor swimming pool. THM water concentration data were obtained from 15 indoor swimming pool facilities in Quebec (Canada). A level III fugacity model is used to estimate inhalation, dermal contact and ingestion exposure doses. The results of the proposed model will be useful to perform a human health risk assessment and develop risk management strategies including developing health-based guidelines for disinfection practices and the design of ventilation system for indoor swimming pools. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Pseudomonas aeruginosa on vinyl-canvas inflatables and foam teaching aids in swimming pools.

    Science.gov (United States)

    Schets, F M; van den Berg, H H J L; Baan, R; Lynch, G; de Roda Husman, A M

    2014-12-01

    Swimming pool-related Pseudomonas aeruginosa infections mainly result in folliculitis and otitis externa. P. aeruginosa forms biofilms on surfaces in the swimming pool environment. The presence of P. aeruginosa on inflatables and foam teaching aids in 24 public swimming pools in the Netherlands was studied. Samples (n = 230) were taken from 175 objects and analysed for P. aeruginosa by culture. Isolated P. aeruginosa were tested for antibiotic resistance by disk diffusion. P. aeruginosa was detected in 63 samples (27%), from 47 objects (27%) in 19 (79%) swimming pools. More vinyl-canvas objects (44%) than foam objects (20%) were contaminated, as were wet objects (43%) compared to dry objects (13%). Concentrations were variable, and on average higher on vinyl-canvas than on foam objects. Forty of 193 (21%) P. aeruginosa isolates from 11 different objects were (intermediate) resistant to one or more of 12 clinically relevant antibiotics, mostly to imipenem and aztreonam. The immediate risk of a P. aeruginosa infection from exposure to swimming pool objects seems limited, but the presence of P. aeruginosa on pool objects is unwanted and requires attention of pool managers and responsible authorities. Strict drying and cleaning policies are needed for infrequently used vinyl-canvas objects.

  4. Health effects from swimming training in chlorinated pools and the corresponding metabolic stress pathways.

    Science.gov (United States)

    Li, Jiang-Hua; Wang, Zhi-Hui; Zhu, Xiao-Juan; Deng, Zhao-Hui; Cai, Can-Xin; Qiu, Li-Qiang; Chen, Wei; Lin, Ya-Jun

    2015-01-01

    Chlorination is the most popular method for disinfecting swimming pool water; however, although pathogens are being killed, many toxic compounds, called disinfection by-products (DBPs), are formed. Numerous epidemiological publications have associated the chlorination of pools with dysfunctions of the respiratory system and with some other diseases. However, the findings concerning these associations are not always consistent and have not been confirmed by toxicological studies. Therefore, the health effects from swimming in chlorinated pools and the corresponding stress reactions in organisms are unclear. In this study, we show that although the growth and behaviors of experimental rats were not affected, their health, training effects and metabolic profiles were significantly affected by a 12-week swimming training program in chlorinated water identical to that of public pools. Interestingly, the eyes and skin are the organs that are more directly affected than the lungs by the irritants in chlorinated water; instead of chlorination, training intensity, training frequency and choking on water may be the primary factors for lung damage induced by swimming. Among the five major organs (the heart, liver, spleen, lungs and kidneys), the liver is the most likely target of DBPs. Through metabolomics analysis, the corresponding metabolic stress pathways and a defensive system focusing on taurine were presented, based on which the corresponding countermeasures can be developed for swimming athletes and for others who spend a lot of time in chlorinated swimming pools.

  5. Swimming pool attendance and risk of asthma and allergic symptoms in children.

    NARCIS (Netherlands)

    Font-Ribera, L.; Kogevinas, M.; Zock, J.P.; Nieuwenhuijsen, M.J.; Heederik, D.; Villanueva, C.M.

    2010-01-01

    Increased asthma risk has been associated with pool attendance in children but evidence is inconsistent and inconclusive. A survey was conducted of 3,223 9-12-yr-old children in Sabadell (Spain) to evaluate association between swimming pool attendance and prevalence of asthma and allergic conditions

  6. Laboratory studies on the effect of ozonation on THM formation in swimming pool water

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Spiliotopoulou, Aikaterini; Cheema, Waqas Akram

    2015-01-01

    Water samples from indoor swimming pool were ozonated at different pH values to evaluate the effect of pH on decomposition of ozone in swimming pool water. Furthermore, drinking and pool water were repeatedly ozonated followed by chlorination to evaluate THM formation. Decomposition of ozone...... was not affected by pH in the range relevant to swimming pools (pH 6.8 – 7.8) and a half-life time at 10-12 min was obtained. Repeating the ozonation, the decomposition of ozone increased at the second dose of ozone added (t½,2=8 min) and then decreased again at the third and fourth dose of ozone (t½,3=17 min; t...... chlorine for drinking water as lower TTHM formation occurred than in non-ozonated samples. For pool water, a higher TTHM formation was observed in ozonated than non-ozonated pool water. Thus, it was observed that ozone reacts markedly different in swimming pool water from the known pattern in drinking...

  7. Determination of Monochloroacetic Acid in Swimming Pool Water by Ion Chromatography-Conductivity Detection

    Directory of Open Access Journals (Sweden)

    Maria Pythias B. Espino

    2013-02-01

    Full Text Available In this study, an analytical method involving ion chromatography with conductivity detection was developed and optimized for the determination of monochloroacetic acid in swimming pool water. The ion chromatographic method has a detection limit of 0.02 mg L-1 and linear range of 0.05 to 1.0 mg L-1 with correlation coeff icient of 0.9992. The method is reproducible with percent RSD of 0.052% (n=10. The recovery of monochloroacetic acid spiked in different water types (bottled, tap and swimming pool water ranged from 28 to 122%. In dilute solutions, chloride and bromide were simultaneously analyzed along with monochloroacetic acid using the optimized method. Chloride and bromide have detection limits of 0.01 to 0.05 mg L-1, respectively. The usefulness of the ion chromatographic method was demonstrated in the analysis of monochloroacetic acid in swimming pool water samples. In such highly-chlorinated samples, an Ag/H cartridge was used prior to the ion chromatographic determination so as to minimize the signal due to chloride ion. Monochloroacetic acid was detected in concentrations between 0.020 and 0.093 mg L-1 in three of the six swimming pool water samples studied. The presence of monochloroacetic acid in the swimming pool water samples suggests the possible occurrence of other disinfection by-products in these waters.

  8. One component, volume heated, boiling pool thermohydraulics

    International Nuclear Information System (INIS)

    Bede, M.; Perret, C.; Pretrel, H.; Seiler, J.M.

    1993-01-01

    Prior work on boiling pools provided heat exchange correlations valid for bubbly flow with laminar or turbulent boundary layers. New experiments performed with water (SEBULON) and UO 2 (SCARABEE BF2) in a churn-turbulent flow configuration show unexpected heat flux distributions for which the maximum heat flux may be situated well below the pool surface. The origin of this behaviour is attributed to condensation effects, very unstable boundary layer flow and surface oscillation. A calculation model is discussed which permits to approach the experimental heat flux distribution with reasonable accuracy. (authors). 7 figs., 2 appendix., 14 refs

  9. Monitoring organic loading to swimming pools by fluorescence excitation–emission matrix with parallel factor analysis (PARAFAC)

    DEFF Research Database (Denmark)

    Seredynska-Sobecka, Bozena; Stedmon, Colin; Boe-Hansen, Rasmus

    2011-01-01

    Fluorescence Excitation–Emission Matrix spectroscopy combined with parallel factor analysis was employed to monitor water quality and organic contamination in swimming pools. The fluorescence signal of the swimming pool organic matter was low but increased slightly through the day. The analysis...... revealed that the organic matter fluorescence was characterised by five different components, one of which was unique to swimming pool organic matter and one which was specific to organic contamination. The latter component had emission peaks at 420nm and was found to be a sensitive indicator of organic...... loading in swimming pool water. The fluorescence at 420nm gradually increased during opening hours and represented material accumulating through the day....

  10. Health Risk Assessment from Haloacetic Acids Exposure in Indoor and Outdoor Swimming Pool Water

    Directory of Open Access Journals (Sweden)

    Weerawat Ounsanaeha

    2017-07-01

    Full Text Available The concentrations of haloacetic acids (HAAs in both indoor and outdoor swimming pools were assessed for cancer and non-cancer health risks with water samples collected during the summer and rainy seasons from two sources. Results showed that average concentrations of HAA5 (MCAA, DCAA, TCAA, MBAA, and DBAA in both indoor and outdoor pools ranged from 74.28 to 163.05 µg/L which was higher than USEPA and WHO water quality standards. Cancer and non-cancer risk values of HAA5 exposure from both swimming pool types were acceptable risks based on USEPA recommendation (10 -6-10-4 and <1, respectively. The highest cancer and non-cancer risk values of HAAs exposure were females for indoor pool and children for outdoor pool, respectively. Cancer and non-cancer risk values of HAA5 exposure from outdoor pool were higher than indoor pool and during the rainy season, respectively. Results indicated that monitoring and control of water quality and accumulated organic substance in swimming pools should be followed to maximize health risk reduction from HAA exposure.

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

    Science.gov (United States)

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

    2018-01-01

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

  12. Effect of nano silica on water quality, health and safety in swimming pools

    Directory of Open Access Journals (Sweden)

    Mirmohammad Kashef

    2012-12-01

    Full Text Available The purpose of this study has been to review of using nano-silica on the efficiency of water treatment of the swimming pool. The current research was an experimental study and was performed in-vitro and experimentally. At first, a nano-particle, called "Nano-Silica", was prepared in the laboratory and herbal additives such as turmeric, curries, saffron and cinnamon were used to increase its antibacterial property. Then, for performing microbiological tests, the water samples of Urmia University's swimming pool were studied in a multi-stage process, in two parts including water samples before adding the nano-particle and after the addition of the nano-particle. Finally, to study the safety and safety, among the relevant factors, the PH and turbidity were studied in the laboratory again in two parts, including before and after the addition of the nano-particle. The survey results showed that there are averages of 2.0633 and 1.0325 before and after adding the nano-particle, respectively, which is higher (P <0.05. Among the mentioned additives, the curries with 92% and the turmeric with 85% had the most antibacterial properties. But the nano-particle did not adjust the swimming pool water PH up to the optimal level of 7.2. However, it reduced the swimming pool water turbidity significantly. This study showed that by using the nano-silica and adding the herbal additives such as cinnamon and saffron, the swimming pool water treatment has reached to a better quality. Keywords: quality, health, safety, nano silica, swimming pool.

  13. [Hygienic profile of the water in Milan swimming pools: a three-year comparative study].

    Science.gov (United States)

    Tesauro, M; Bianchi, A; Consonni, M; Bollani, M; Cesaria, M; Trolli, F Radice; Galli, M G

    2010-01-01

    The aim of this work was to determine whether swimming pool water quality in Milan from 2006 to 2008 was within the standards established by national and local Italian laws (Circolare Min. Sanità 128/71 and DGR 2552/2006). In 2006, 580 samples of water from public swimming pools were analyzed to determine the presence of heterotrophic counts at 37 degrees and total coliforms; pH, free chlorine and chloride of each sample were also measured. In the following years, water from both public and private swimming pools were examined to measure heterotrophic count at 22 degrees and 36 degrees, Escherichia coli, enterococci, Pseudomonas aeruginosa, Staphylococcus aureus, pH, free chlorine, and nitrates. The total number of analyses carried out in 2007 and 2008 was 2074 and 1532, respectively. In 2006, the extent of noncompliance of all swimming pools that was observed for both physical/chemical and microbiological parameters was 72.3%, which then decreased to 53.2% and 36.2% in 2007 and 2008, respectively. In particular with regard to the microbiological analysis, an increase of noncompliance based on at least one parameter was determined (7.1% in 2006 vs. 21.5% in 2007 and 22% in 2008). In contrast, a decrease of the extent of noncompliance based on at least one physical/chemical parameter was observed (from 68.1% in 2006 to 40.4% and 22.3% in 2007 and 2008, respectively). Interestingly, public swimming pools exceeded the legal limits of microbiological concentration more often than the private ones, whereas both types of swimming pools showed a decrease in noncompliance with regard to the physical/chemical parameters.

  14. Enhanced heat transfer in confined pool boiling

    NARCIS (Netherlands)

    Rops, C.M.; Lindken, R.; Velthuis, J.F.M.; Westerweel, J.

    2009-01-01

    We report the results of an experimental investigation of the heat transfer during nucleate boiling on a spatially confined boiling surface. The heat flux as a function of the boiling surface temperature was measured in pool boiling pots with diameters ranging from 15 mm down to 4.5 mm. It was found

  15. Particles in swimming pool filters – Does pH determine the DBP formation?

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Willach, Sarah; Mosbæk, Hans

    2012-01-01

    The formation was investigated for different groups of disinfection byproducts (DBPs) during chlorination of filter particles from swimming pools at different pH-values and the toxicity was estimated. Specifically, the formation of the DBP group trihalomethanes (THMs), which is regulated in many...... or initial free chlorine concentrations the particles were chlorinated at different pH-values in the relevant range for swimming pools. THM and HAA formations were reduced by decreasing pH while HAN formation increased with decreasing pH. Based on the organic content the relative DBP formation from...

  16. Perceived health problems in swimmers according to the chemical treatment of water in swimming pools.

    Science.gov (United States)

    Fernández-Luna, Álvaro; Burillo, Pablo; Felipe, José Luis; del Corral, Julio; García-Unanue, Jorge; Gallardo, Leonor

    2016-01-01

    The objective of this study was to determine which chemical treatment used for disinfecting water in indoor swimming pools had the least impact on users' perceptions of health problems, and which generated the greatest satisfaction with the quality of the water. A survey on satisfaction and perceived health problems was given to 1001 users at 20 indoor swimming pools which used different water treatment methods [chlorine, bromine, ozone, ultraviolet lamps (UV) and salt electrolysis]. The findings suggest that there is a greater probability of perceived health problems, such as eye and skin irritation, respiratory problems and skin dryness, in swimming pools treated with chlorine than in swimming pools using other chemical treatment methods. Pools treated with bromine have similar, although slightly better, results. Other factors, such as age, gender, time of day of use (morning and afternoon) and type of user (competitive and recreational), can also affect the probability of suffering health problems. For all of the above, using combined treatment methods as ozone and UV, or salt electrolysis produces a lower probability of perceived health problems and greater satisfaction.

  17. Microbial quality of swimming pool water with treatment without disinfection, with ultrafiltration, with UV-based treatment and with chlorination

    NARCIS (Netherlands)

    Keuten, M.G.A.; Peters, M.C.F.M.; van Dijk, J.C.; van Loosdrecht, Mark C.M.; Rietveld, L.C.

    2017-01-01

    Swimming pools are traditionally disinfected with a residual disinfectant such as sodium hypochlorite. Nowadays, swimming water without a residual disinfectant is increasingly popular, as can be seen by the growing number of (natural) swimming ponds (Weilandt 2015), but health risks for bathers do

  18. Occurrence and simulation of trihalomethanes in swimming pool water: A simple prediction method based on DOC and mass balance.

    Science.gov (United States)

    Peng, Di; Saravia, Florencia; Abbt-Braun, Gudrun; Horn, Harald

    2016-01-01

    Trihalomethanes (THM) are the most typical disinfection by-products (DBPs) found in public swimming pool water. DBPs are produced when organic and inorganic matter in water reacts with chemical disinfectants. The irregular contribution of substances from pool visitors and long contact time with disinfectant make the forecast of THM in pool water a challenge. In this work occurrence of THM in a public indoor swimming pool was investigated and correlated with the dissolved organic carbon (DOC). Daily sampling of pool water for 26 days showed a positive correlation between DOC and THM with a time delay of about two days, while THM and DOC didn't directly correlate with the number of visitors. Based on the results and mass-balance in the pool water, a simple simulation model for estimating THM concentration in indoor swimming pool water was proposed. Formation of THM from DOC, volatilization into air and elimination by pool water treatment were included in the simulation. Formation ratio of THM gained from laboratory analysis using native pool water and information from field study in an indoor swimming pool reduced the uncertainty of the simulation. The simulation was validated by measurements in the swimming pool for 50 days. The simulated results were in good compliance with measured results. This work provides a useful and simple method for predicting THM concentration and its accumulation trend for long term in indoor swimming pool water. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Color Fringes Bordering Black Stripes at the Bottom of a Swimming Pool

    Science.gov (United States)

    Fuster, Gonzalo; Rojas, Roberto; Slüsarenko, Viktor

    2016-01-01

    We have observed a nice example of chromatic dispersion due to refraction in water, in the form of color fringes bordering the black stripes that exist at the bottom of a swimming pool. Here we give a qualitative description of the phenomenon, explaining the role of the black stripes and the dispersive index of refraction of water.

  20. Swimming Pool Water Treatment Chemicals and/or Processes. Standard No. 22.

    Science.gov (United States)

    National Sanitation Foundation, Ann Arbor, MI.

    Chemicals or processes used or intended for use, in the treatment of swimming pool water are covered. Minimum public health limits or acceptability in regard to toxicity, biocidal effectiveness, and chemical behavior and analysis are presented. The appendices give guidelines to the scientific and statistically sound evaluations to determine the…

  1. Centrifugal Pumps for Swimming Pools. National Sanitation Foundation Standard Number 17.

    Science.gov (United States)

    National Sanitation Foundation, Ann Arbor, MI. Committee for Swimming Pool Equipment Standards.

    The pumps discussed herein are intended to be used for recirculating water in swimming pools, both public and private. Included are the basic components which may be a part of a pump such as the housing, strainer, impeller, valves, and such other parts as are attached or a part of the pump as supplied by the manufacturer. This standard is intended…

  2. Photolytic removal of DBPs by medium pressure UV in swimming pool water

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Zortea, R.; Piketty, A.

    2013-01-01

    Medium pressure UV is used for controlling the concentration of combined chlorine (chloramines) in many public swimming pools. Little is known about the fate of other disinfection by-products (DBPs) in UV treatment. Photolysis by medium pressure UV treatment was investigated for 12 DBPs reported...

  3. The effect of UV treatment on highly polluted and normal operated swimming pools

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2017-01-01

    “It should be light blue, transparent” (Mario Andrada, speakerman, Olympic Games, Rio, 2016) was the comment for the “green lake”. Swimming pools are sensitive recirculating systems. A malfunction in water treatment units or a poor operating decision could possibly lead to health-endangering or a...

  4. [Surveillance of the sanitary conditions of a public swimming pool in the city of Palermo (Italy)].

    Science.gov (United States)

    Maida, Carmelo Massimo; Di Benedetto, Maria Antonella; Firenze, Alberto; Calamusa, Giuseppe; Di Piazza, Florinda; Milici, Maria Eleonora; Romano, Nino

    2008-01-01

    In a previous study we evaluated the microbiological quality of water of seven pools in the city of Palermo through evaluation of bacterial indicators of faecal contamination and of protozoa (Giardia and Cryptosporidium). In this study we also searched for the presence of fungi in two swimming pools of a public swimming facility in the same city. Samples were collected from both pools, their filtration systems and floor surfaces of the facility. Chemical-physical and microbiological examination of water of the two pools have shown that quality of water depends on the concentration of residual free chlorine and on the number of bathers in the pool. The values of four microbiological parameters (bacterial load at 22 degrees C and 36 degrees C, presence of coagulase-negative Staphylococci and Pseudomonas spp.) increased with diminishing chlorine concentrations and with increasing number of pool users. Faecal bacteria, Giardia and Cryptosporidium were not found. On the other hand, various fungi were isolated from floor surfaces and pool water even in the presence of optimal chlorine concentrations. This study confirms the importance of regular maintenance of pool disinfection systems and suggests the need to search for other micro-organisms not included in the current legislation (Giardia, Cryptosporidium and fungi).

  5. An Investigation on Physicochemical and Microbial Water Quality of Swimming Pools in Yazd

    Directory of Open Access Journals (Sweden)

    M Dehvari

    2012-08-01

    Full Text Available Introduction: Disrespect of health regulations and proper disinfection of water and swimming pools is effective in incidence of health problems and transfer of infectious diseases to swimmers. The aim of this research was to investigate water of swimming pools in Yazd city and compare the results with national standards. Methods: In this study, 11 active covered swimming pools of Yazd city were sampled as census. Parameters of temperature, pH, amount of free and Combined chlorine residual, turbidity, alkalinity, hardness, the population of heterotrophic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, fecal streptococci, and fecal coliforms were studied. Sampling has been conducted every two weaks for 3 months and samples were analyzed under standard procedures. Results: In this research, amount of pH in 84.73%, free residual chlorine in 44.18%, Combined residual chlorine in 72.45%, alkalinity in19.82%, turbidity in 86.36%, hardness in 57.18% and temperature in 13.73% Samples were desirable. The fecal streptococci bacteria was not shown in all the swimming pools and population of heterotrophic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa and fecal coliforms in 56.73%, 93.27%, 79.36% and 91.45% cases were desirable, respectively. Statistical analysis indicated that there is a direct relationship between Water turbidity and population of heterotraphic bacteria. Conclusion: According to the results, the parameters of heterotrophic bacteria population, also the alkalinity and temperature had the least compliant with the standards that shows the necessity for continuous monitoring of physical, chemical and microbial parameters and also control of filtration and disinfection of water condition of swimming pools.

  6. Occupational exposures of airborne trichloramine at indoor swimming pools in Taipei.

    Science.gov (United States)

    Chu, Tsai-Shu; Cheng, Shu-Fang; Wang, Gen-Shuh; Tsai, Shih-Wei

    2013-09-01

    Ten indoor swimming pools in Taipei, Taiwan were included in the study to assess the exposure of people to airborne trichloramine (NCl3) and also to discover the factors that might affect the associated concentrations. An active air sampling method was performed to determine the levels of NCl3, while questionnaires were administered to swimming pool workers, including lifeguards, swimming instructors, and management employees. The results show that the concentrations of trichloramine ranged from 0.017 to 0.15 mg m(-3), which were generally lower than what have been reported from other studies. Symptoms of sore throat and phlegm were more frequent among lifeguards and swimming instructors (exposure group) than management employees (reference group) (odds ratios were 11.28 and 4.22 for sore throat and phlegm, respectively). It seems that the current exposure limit for airborne NCl3, which was recommended by WHO, was not lower enough to protect the health of pool attendants. Regulated level of free available chlorine in Taipei (i.e., 0.3-0.7 ppm) is lower than what is required in other countries (e.g., 1-3 ppm in the UK). This might be the main reason why the concentrations of NCl3 reported elsewhere were higher than what were found in this research. Further international comparisons will help to elucidate if low free chlorine concentration should be adopted as an operating standard. For the indoor swimming pools in Taipei, the air quality is suggested to be improved, since even with the low concentrations of NCl3, higher respiratory ailments among pool workers were observed. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Prevalence of dental erosion in adolescent competitive swimmers exposed to gas-chlorinated swimming pool water.

    Science.gov (United States)

    Buczkowska-Radlińska, J; Łagocka, R; Kaczmarek, W; Górski, M; Nowicka, A

    2013-03-01

    The purpose of this study was to analyze the prevalence of dental erosion among competitive swimmers of the local swimming club in Szczecin, Poland, who train in closely monitored gas-chlorinated swimming pool water. The population for this survey consisted of a group of junior competitive swimmers who had been training for an average of 7 years, a group of senior competitive swimmers who had been training for an average of 10 years, and a group of recreational swimmers. All subjects underwent a clinical dental examination and responded to a questionnaire regarding aspects of dental erosion. In pool water samples, the concentration of calcium, magnesium, phosphate, sodium, and potassium ions and pH were determined. The degree of hydroxyapatite saturation was also calculated. Dental erosion was found in more than 26 % of the competitive swimmers and 10 % of the recreational swimmers. The lesions in competitive swimmers were on both the labial and palatal surfaces of the anterior teeth, whereas erosions in recreational swimmers developed exclusively on the palatal surfaces. Although the pH of the pool water was neutral, it was undersaturated with respect to hydroxyapatite. The factors that increase the risk of dental erosion include the duration of swimming and the amount of training. An increased risk of erosion may be related to undersaturation of pool water with hydroxyapatite components. To decrease the risk of erosion in competitive swimmers, the degree of dental hydroxyapatite saturation should be a controlled parameter in pool water.

  8. Determination of Bacterial Quality of Water in Randomly Selected Swimming Pools in Kampala City, Uganda

    Directory of Open Access Journals (Sweden)

    Joyce Margaret Ekopai

    2017-01-01

    Full Text Available Swimming pools have become major recreation facilities for leisure and sports in cities across the world, but the standard guidelines, particularly in developing countries, are not adhered to because little is known about the contaminants in the pools and the possible health risks involved. This study provides a survey of bacterial quality of water from swimming pools in Kampala. A total of 26 water samples were collected from 13 outdoor swimming pools in Kampala between January and June 2016 and analysed for total aerobic plate count (TPC, Escherichia coli, coliforms, and Salmonella. The heterotrophic bacterial load ranged between 0 and 6.35 × 105 cfu/ml, where 6.35 × 105 cfu/ml was the highest load and 3 × 101 cfu/ml the least. The highest average TPC was 6.19 × 105 cfu/ml and the lowest 5.07 × 103 cfu/ml. 30.8% of the pools had TPC within acceptable limits (≤5 × 102 cfu/ml, whereas 69.2% were highly contaminated and did not conform to the Uganda National Water and Sewerage Corporation standards of recreational water quality for both treated (0 cfu/100 mls water and untreated (10 cfu/100 mls water. Although no positive results were yielded for E. coli, coliforms, and Salmonella, TPC represented the presence of heterotrophic bacteria which are often indicated in opportunistic infections.

  9. Gene expression changes in blood RNA after swimming in a chlorinated pool.

    Science.gov (United States)

    Salas, Lucas A; Font-Ribera, Laia; Bustamante, Mariona; Sumoy, Lauro; Grimalt, Joan O; Bonnin, Sarah; Aguilar, Maria; Mattlin, Heidi; Hummel, Manuela; Ferrer, Anna; Kogevinas, Manolis; Villanueva, Cristina M

    2017-08-01

    Exposure to disinfection by-products (DBP) such as trihalomethanes (THM) in swimming pools has been linked to adverse health effects in humans, but their biological mechanisms are unclear. We evaluated short-term changes in blood gene expression of adult recreational swimmers after swimming in a chlorinated pool. Volunteers swam 40min in an indoor chlorinated pool. Blood samples were drawn and four THM (chloroform, bromodichloromethane, dibromochloromethane and bromoform) were measured in exhaled breath before and after swimming. Intensity of physical activity was measured as metabolic equivalents (METs). Gene expression in whole blood mRNA was evaluated using IlluminaHumanHT-12v3 Expression-BeadChip. Linear mixed models were used to evaluate the relationship between gene expression changes and THM exposure. Thirty-seven before-after pairs were analyzed. The median increase from baseline to after swimming were: 0.7 to 2.3 for MET, and 1.4 to 7.1μg/m 3 for exhaled total THM (sum of the four THM). Exhaled THM increased on average 0.94μg/m 3 per 1 MET. While 1643 probes were differentially expressed post-exposure. Of them, 189 were also associated with exhaled levels of individual/total THM or MET after False Discovery Rate. The observed associations with the exhaled THM were low to moderate (Log-fold change range: -0.17 to 0.15). In conclusion, we identified short-term gene expression changes associated with swimming in a pool that were minor in magnitude and their biological meaning was unspecific. The high collinearity between exhaled THM levels and intensity of physical activity precluded mutually adjusted models with both covariates. These exploratory results should be validated in future studies. Copyright © 2017. Published by Elsevier B.V.

  10. An outbreak of adenovirus type 3 disease at a private recreation center swimming pool.

    Science.gov (United States)

    Martone, W J; Hierholzer, J C; Keenlyside, R A; Fraser, D W; D'Angelo, L J; Winkler, W G

    1980-02-01

    In the period June 6--July 24, 1977, and outbreak of illness due to adenovirus type 3 (AV3) occurred in residents of a suburban community (Community A), Dekalb County, Georgia. Based on surveys, at least 105 cases occurred. The illness was primarily characterized by sore throat, fever, headache, and anorexia. Conjunctivitis affected only 34 of 105 (32%) of the individuals in two surveys. Frequent use of a private swimming pool was associated with illness in Community A residents. The outbreak coincided with a temporary defect in the pool filtration system which probably prevented maintenance of proper chlorine levels in the pool water, and suggested that the infection was spread by pool water. However, the predominant mode of transmission could not be shown conclusively to be waterborn rather than person-to-person.

  11. Optimal pH in chlorinated swimming pools - balancing formation of by-products

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Albrechtsen, Hans-Jørgen; Andersen, Henrik Rasmus

    2013-01-01

    -products. The chlorine-to-precursor ratio used in the batch experiments influenced the amounts of by-products formed, but regardless of the ratio the same trends in the effect of pH were observed. Trihalomethane formation was reduced by decreasing pH but haloacetonitrile and trichloramine formation increased......In order to identify the optimal pH range for chlorinated swimming pools the formation of trihalomethanes, haloacetonitriles and trichloramine was investigated in the pH-range 6.5–7.5 in batch experiments. An artificial body fluid analogue was used to simulate bather load as the precursor for by.......7 or lower. An optimal pH range for by-products formation in swimming pools was identified at pH 7.0–7.2. In the wider pH range (pH 6.8–7.5) the effect on by-product formation was negligible. Swimming pools should never be maintained at lower pH than 6.8 since formation of both haloacetonitriles...

  12. Ultrafiltration for Purification and Treatment of Water Streams in Swimming Pool Circuits

    Directory of Open Access Journals (Sweden)

    Edyta Łaskawiec

    2018-05-01

    Full Text Available The paper presents possible applications of pressure-driven membrane processes for treatment of swimming pool water and purification of waste streams – washings. Newly identified swimming pool water quality issues are presented that require a modernization of existing technologies. The studies used polymer membranes with the same particle distribution range (50000 Da, but made of different membrane-forming materials: polyvinylidene difluoride (PVDF and polyether sulfone (PES for purification of washings. The ultrafiltration process allowed obtaining a high turbidity reduction rate in washings (over 95%, and also a significant reduction of total organic carbon. The effectiveness of the PES membrane was reduced after the process commencement, whereas the separation capacity of the PVDF membrane increased during the studied filtration process. While setting the operational process parameters consideration should be given also to the resistance of used membranes to chlorine present in the swimming pool water. A prolonged exposure of the polyether sulfone membrane to chloride may have caused its gradual damage and degradation of its separation properties.

  13. Occurrence ofCryptosporidiumandGiardiaand the Relationship between Protozoa and Water Quality Indicators in Swimming Pools.

    Science.gov (United States)

    Xiao, Shumin; Yin, Pengna; Zhang, Yan; Hu, Sike

    2017-04-01

    A total of 60 samples were collected from 35 swimming pools in Beijing, China, and the presence of Cryptosporidium and Giardia were investigated. The results showed that 16.7% and 15.0% of samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively, with a mean concentration of 0.30 oocysts/10 L and 0.27 cysts/10 L. The oocysts and cysts were found to have higher rates of occurrence in August than in May. Genotyping confirmed the presence of Cryptosporidium hominis, C. parvum , and Giardia assemblages A and B, all of which were associated with human infections. The predominant species/assemblages were C. hominis and Giardia assemblage A. Analyses of the relationships between parasite oocysts/cysts, indicator bacteria, and physical-chemical parameters revealed that there was no correlation between 2 parasites and fecal bacterial indicators, whilst there was a significant correlation between protozoa and urea concentration, which indicates that urea concentration rather than fecal bacterial indicators might be an appropriate index for chlorine-resistant protozoa in swimming pools. This study provides useful information to improve the safety of swimming pool water and deduce the risk of protozoan infections.

  14. QUALITATIVE ASSESSMENT OF INDOOR SWIMMING POOL AND SEASONAL BATHING RESORTS WATER USING MICROTOX® TEST

    Directory of Open Access Journals (Sweden)

    Edyta Łaskawiec

    2016-12-01

    Full Text Available The tests were to specify the toxic effect on the basis of Vibrio fischeri luminescence inhibition caused by chemical compounds present in pool water samples. The testing tool was Microtox®; This biotest produces quick results thus making it a comfortable tool for testing water for various toxicants. Furthermore, UV254 absorbance measure was carried out and its value was a proxy parameter for defining participation of precursors to disinfection by-products in the samples. Some of the samples had high UV254 values, one of them was 144 m 1. The Microtox® quality tests of indoor and outdoor swimming pool water presented in the paper proved impact of such factors like air exchange or supply of pool water circulation on water quality. Seasonal bathing waters had lower toxicity values. In the context of the work specifies that the impurities in the water cause its toxicity. However, there was no relationship between high UV254 absorbance values and higher toxicity of the samples. The toxicological analysis may serve as a screening test of swimming pool water quality. It is of key importance to check the free chlorine value for a water sample. High chlorine concentration can cause higher bioluminescence inhibition values.

  15. Acute changes in serum immune markers due to swimming in a chlorinated pool.

    Science.gov (United States)

    Vlaanderen, Jelle; van Veldhoven, Karin; Font-Ribera, Laia; Villanueva, Cristina M; Chadeau-Hyam, Marc; Portengen, Lützen; Grimalt, Joan O; Zwiener, Christian; Heederik, Dick; Zhang, Xiangru; Vineis, Paolo; Kogevinas, Manolis; Vermeulen, Roel

    2017-08-01

    Exposure to disinfectants and disinfection byproducts (DBPs) due to swimming in chlorinated water has been associated with allergic and respiratory health effects, including asthma. Biological mechanisms contributing to these associations are largely unknown. We hypothesized a potential pathway involving modulation of the immune system. We assessed levels of immune markers (CCL11, CCL22, CXCL10, CRP, EGF, GCSF, IL-8, IL-17, IL-1RA, MPO, VEGF, Periostin) in serum collected from 30 women and 29 men before and after 40min of swimming in a chlorinated pool. Exposure to DBPs was assessed by measuring bromodichloromethane, bromoform, chloroform, and dibromochloromethane in exhaled breath before and after swimming. Covariate data including information on physical activity was available through questionnaires and measurements. We assessed the association between indicators of swimming in a chlorinated pool and changes in serum immune marker concentrations using linear regression with bivariate normal distributions and adjusted for multiple comparisons by applying the Benjamini-Hochberg procedure. We observed a significant decrease in serum concentrations of IL-8 (-12.53%; q=2.00e-03), CCL22 (-7.28%; q=4.00e-04), CCL11 (-7.15%; q=9.48e-02), CRP (-7.06%; q=4.68e-05), and CXCL10 (-13.03%; q=6.34e-14) and a significant increase in IL-1RA (20.16%; q=4.18e-06) from before to after swimming. Associations with quantitative measurements of DBPs or physical activity were similar in direction and strength. Most of the observed associations became non-significant when we adjusted the effects of exposure to DBPs for physical activity or vice-versa. Our study indicates that swimming in a chlorinated pool induces perturbations of the immune response through acute alterations of patterns of cytokine and chemokine secretion. The observed effects could not be uniquely attributed to either exposure to DBPs or physical activity. Evidence in the literature suggests that observed decreases in

  16. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2015-01-01

    be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence...... trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates......Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile...

  17. The effect of UV treatment on highly polluted and normal operated swimming pools

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2017-01-01

    Water samples from 2 indoor public swimming pool facilities with significantly different organic matter concentrations in the recirculation were tested to evaluate UV-induced effects on water chemistry. The aim of the study was to investigate the impact of poor water quality due to increased...... organic carbon (TOC) and the potential effect of increased nitrate concentration on disinfection by-product (DBP) formation in pool water. Concentration change on total trihalomethanes (TTHM) was investigated utilising medium pressure UV treatment in conjunction with chlorine. Post-UV chlorine consumption...... increased, UV dose-dependently. The post-UV chlorination clearly induced TTHM formation in both polluted and normal operated pools. However, elevated TOC concentration did not increase significantly the DBP formation. Regarding the brominated fraction of the halogens in the formed TTHMs, it appeared...

  18. Effect of selection of pH in swimming pool on formation of chlorination by-products

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Willach, Sarah; Mosbæk, Hans

    2011-01-01

    Chlorine is used as disinfection agent in public swimming pools, but also reacts with organic matter in the water forming chlorinat ed disinfection by-products. In order to evaluate the effect of choice of pHsetpoint in the pool we investigated the effect of chlorination of artificial body fluid...

  19. Kick, Stroke and Swim: Complement Your Swimming Program by Engaging the Whole Body on Dry Land and in the Pool

    Science.gov (United States)

    Flynn, Susan; Duell, Kelly; Dehaven, Carole; Heidorn, Brent

    2017-01-01

    The Kick, Stroke and Swim (KSS) program can be used to engage students in swimming-skill acquisition and fitness training using a variety of modalities, strategies and techniques on dry land. Practicing swim strokes and techniques on land gives all levels of swimmers--from beginner to competitive--a kinesthetic awareness of the individual…

  20. Disinfection by-product formation of UV treated swimming pool water

    DEFF Research Database (Denmark)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2015-01-01

    could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation of DBPs....... The trihalomethane induction might result from a kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of the halogens in the formed trihalomethanes increased with UV dose, which......-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed. The post-UV chlorination clearly induced formation of DBPs; however, for the total trihalomethanes (TTHM), the inductions were not more than what...

  1. A survey of fungi and some indicator bacteria in chlorinated water of indoor public swimming pools

    Energy Technology Data Exchange (ETDEWEB)

    Aho, R.; Hirn, J.

    1981-01-01

    Fifty-four water samples, of volume 500 ml, originating from six public indoor fresh water swimming pools were examined for the presence of fungi and some indicator bacteria by a membrane-filter method. Sabouraud-dextrose agar and selective Candida albicans-medium were used for isolation and identification of fungi. In all but one of the samples the free chlorine content was above 0.40 mg/l. No Candida albicans were detected. Molds and unidentified yeasts were isolated from 29 of the samples. The following species were recorded: Acremonium spp., ALternaria sp., Aspergillus spp., Candida guilliermondii, Chaetomium sp., Cladosporium spp., Clasterosporium sp., Fusarium spp., Geotrichium sp., Penicillium spp., Petriellidium boydii and Phoma spp. Their occurrence was sporadic, each species mostly appearing as single colonies only, with a maximum of 5 colonies. Bacterial growth was noticed in 15 samples, but only in the sample of low free chlorine content did this reach significant proportions. The study indicates that the standard of chlorination is, at least in general, an adequate measure against fungal contamination of swimming pool water. However, the spectrum of mold species encountered encourages a further search for possible indicator species among these organisms.

  2. Pseudomonas aeruginosa in Swimming Pool Water: Evidences and Perspectives for a New Control Strategy

    Directory of Open Access Journals (Sweden)

    Marco Guida

    2016-09-01

    Full Text Available Pseudomonas aeruginosa is frequently isolated in swimming pool settings. Nine recreational and rehabilitative swimming pools were monitored according to the local legislation. The presence of P. aeruginosa was correlated to chlorine concentration. The ability of the isolates to form a biofilm on plastic materials was also investigated. In 59.5% of the samples, microbial contamination exceeded the threshold values. P. aeruginosa was isolated in 50.8% of these samples. The presence of P. aeruginosa was not correlated with free or total chlorine amount (R2 < 0.1. All the isolates were moderate- to strong-forming biofilm (Optical Density O.D.570 range 0.7–1.2. To control biofilm formation and P. aeruginosa colonization, Quantum FreeBioEnergy© (QFBE, FreeBioEnergy, Brisighella, Italy, has been applied with encouraging preliminary results. It is a new, promising control strategy based on the change of an electromagnetic field which is responsible for the proliferation of some microorganisms involved in biofilm formation, such as P. aeruginosa.

  3. Isolation and identification of Acanthamoeba spp. from thermal swimming pools and spas in Southern Brazil.

    Science.gov (United States)

    Fabres, Laura Fuhrich; Rosa Dos Santos, Sayonara Peixoto; Benitez, Lisianne Brittes; Rott, Marilise Brittes

    2016-03-01

    Free-living amoebae (FLA) are widely distributed in soil and water. A few number of them are implicated in human disease: Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris and Sappinia diploidea. Species of Acanthamoeba can cause keratitis and brain infections. In this study, 72 water samples were taken from both hot tubs and thermal swimming pools in the city of Porto Alegre, RS, Brazil, to determine the presence of Acanthamoeba in the water as well as perform the phenotypic and genotypic characterization of the isolates. The identification of the isolates was based on the cysts morphology and PCR amplification using genus-specific oligonucleotides. When the isolates were submitted to PCR reaction only 8 were confirmed as belonging to the genus Acanthamoeba. The sequences analysis when compared to the sequences in the GenBank, showed genotype distribution in group T3 (12,5%), T5 (12,5%), T4 (25%) and T15 (50%). The results of this study confirmed the presence of potentially pathogenic isolates of free living amoebae in hot swimming pool and spas which can present risks to human health.

  4. [Investigation and comparison of behaviours of adults and children in swimming pools].

    Science.gov (United States)

    Bonini, M; Bodina, A; Bonali, D; Bascucci, B; Pellino, P; Castaldi, S

    2011-01-01

    The swimmers health's protection must be achieved through the implementation of structures that respect safety standards, the best management of the structures and the users'compliance with rules that minimize the potential risks to health, now clearly identified by the World Health Organization in specific guidelines and by the national and regional legislation. An anonymous questionnaire has been used in order to detect the level of knowledge of hygienic risks and the behaviour of costumers (adults and children) of swimming pool. Comparing the answers, statistically significant differences in the behaviours of adults and children were found in order to protect their own and others' health. In particular children do shower and go through footbath before entering the swimming pool more than adults (respectively 89.2% versus 77.4% and 89.2% versus 79.4%). No differences in the behaviours of the two groups were found in the use of dedicated footwear and caps. Children are predisposed to follow the rules because they are more loyal to duty, while adults comply with the rules only when it is clear the advantage to protect their health. This paper underline the importance of health education programs that can help people to understand the importance of adopting certain behaviours in order to prevent risks and promote health for the benefit of all.

  5. Occurrence of pharmaceuticals and UV filters in swimming pools and spas.

    Science.gov (United States)

    Ekowati, Yuli; Buttiglieri, Gianluigi; Ferrero, Giuliana; Valle-Sistac, Jennifer; Diaz-Cruz, M Silvía; Barceló, Damià; Petrovic, Mira; Villagrasa, Marta; Kennedy, Maria D; Rodríguez-Roda, Ignasi

    2016-07-01

    The occurrence of 32 pharmaceuticals and 14 UV filters in swimming pools and spas was studied. Fifty-one water samples were collected from 17 pools located in sport centres and hotels in Catalonia, Spain. The samples were analysed by liquid chromatography-tandem mass spectrometry. The pharmaceuticals atenolol, carbamazepine, hydrochlorothiazide, metronidazole, ofloxacin, sulfamethoxazole, acetaminophen, ibuprofen, ketoprofen and phenazone were measured in water samples at concentrations higher than their limit of quantification (LOQ). The highest concentration of any individual pharmaceutical was measured for the diuretic hydrochlorothiazide (904 ng/L). The most frequently detected pharmaceutical was carbamazepine, as it was observed in more than half of all the water samples measured (53 %, 27/51). The UV filters at concentrations higher than LOQ in water samples were BP1, BP2, BP3, BP8, THB, 4DHB, 4MBC, OD-PABA, 1HBT, MeBT and DMeBT. The highest concentration of UV filter observed was 4MBC (69.3 ng/L) while the most frequent UV filters in the samples were 1HBT (59 %, 30/51). The results also showed that pharmaceuticals and UV filters were most frequently found in spas. Finally, from a water treatment technology perspective, the lowest occurrence of pharmaceuticals was in the pools applying sand filters followed by disinfection by sodium hypochlorite, while the lowest occurrence of UV filters was in the pools applying coagulation, sand filtration, UV and salt electrolysis.

  6. Chloroform in indoor swimming-pool air: monitoring and modeling coupled with the effects of environmental conditions and occupant activities.

    Science.gov (United States)

    Hsu, H T; Chen, M J; Lin, C H; Chou, W S; Chen, J H

    2009-08-01

    Human exposure to chloroform in indoor swimming pools has been recognized as a potential health concern. Although environmental monitoring is a useful technique to investigate chloroform concentrations in indoor swimming-pool air, in practice, the interpretations of measured data would inevitably run into difficulties due to the complex interactions among the numerous variables, including environmental conditions and occupant activities. Considering of the relevant variables of environmental conditions and occupant activities, a mathematical model was first proposed to predict the chloroform concentration in indoor swimming-pool air. The developed model provides a straightforward, conceptually simple way to predict the indoor air chloroform concentration by calculating the mass flux, J, and the Péclet number, Pe, and by using a heuristic value of the indoor airflow recycle ratio, R. The good agreement between model simulation and measured data demonstrates the feasibility of using the presented model for indoor air quality management, operational guidelines and health-related risk assessment.

  7. Blanket and vacuum vessel design of the next tokamak. (Swimming pool type)

    International Nuclear Information System (INIS)

    Iida, H.; Minato, A.; Kitamura, K.

    1983-01-01

    The structural design study of a reactor module for a swimming pool type reactor (SPTR) was conducted. Since pool water plays the role of radiation shielding in the SPTR, the module does not have a solid shield. It consists of tritium breeding blankets, divertor collector plates and a vacuum vessel. The object of this study is to show the reactor module design which has a simple structure and a sufficient tritium breeding ratio. A large coverage of the plasma chamber surface with tritium breeding blanket is essential in order to obtain a high tritium breeding ratio. A breeding blanket is also placed behind the divertor collector plate, i.e. in the upper and lower region, as well as in the outboard and inboard regions of the module. A concept in which the first wall is an integral part of the blanket is employed to minimize the thickness of structural and cooling material brazed in front of the breeding material (Li 2 O) and to enhance the tritium breeding capability. In order to simplify the module structure the vacuum vessel and breeding blanket is also integrated in the inboard region. One of the features inherent in the swimming pool type reactor is an additional external force on the vacuum vessel, namely hydraulic pressure. A detailed structural analysis of the vacuum vessel is performed. Divertor collector plates are assemblies of co-axial tubes. They minimize the electromagnetic force on the plate induced by the plasma disruption. A thermal and structural analysis and life time estimation of the first wall and divertor collector plates are performed. (author)

  8. Secondary formation of disinfection by-products by UV treatment of swimming pool water.

    Science.gov (United States)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla M S; Andersen, Henrik R

    2015-07-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  9. Trihalomethanes in Lisbon indoor swimming pools: occurrence, determining factors, and health risk classification.

    Science.gov (United States)

    Silva, Zelinda Isabel; Rebelo, Maria Helena; Silva, Manuela Manso; Alves, Ana Martins; Cabral, Maria da Conceição; Almeida, Ana Cristina; Aguiar, Fátima Rôxo; de Oliveira, Anabela Lopes; Nogueira, Ana Cruz; Pinhal, Hermínia Rodrigues; Aguiar, Pedro Manuel; Cardoso, Ana Sofia

    2012-01-01

    Characterization of water quality from indoor swimming pools, using chorine-based disinfection techniques, was performed during a 6-mo period to study the occurrence, distribution, and concentration factors of trihalomethanes (THM). Several parameters such as levels of water THM, water and air chloroform, water bromodichloromethane (BDCM), water dibromochloromethane (DBCM), water bromoform (BF), free residual chlorine (FrCl), pH, water and air temperature, and permanganate water oxidizability (PWO) were determined in each pool during that period. Chloroform (CF(W)) was the THM detected at higher concentrations in all pools, followed by BDCM, DBCM, and BF detected at 99, 34, and 6% of the samples, respectively. Water THM concentrations ranged from 10.1 to 155 μg/L, with 6.5% of the samples presenting values above 100 μg/L (parametric value established in Portuguese law DL 306/2007). In this study, air chloroform (CF(Air)) concentrations ranged from 45 to 373 μg/m³ with 24% of the samples presenting values above 136 μg/m³ (considered high exposure value). Several significant correlations were observed between total THM and other parameters, namely, CF(W), CF(Air), FrCl, water temperature (T(W)), and PWO. These correlations indicate that FrCl, T(W) and PWO are parameters that influence THM formation. The exposure criterion established for water THM enabled the inclusion of 67% of Lisbon pools in the high exposure group, which reinforces the need for an improvement in pool water quality.

  10. Radon measurements in air in waterworks and indoor swimming pools - a primary mapping project

    International Nuclear Information System (INIS)

    Marinko, J.; Mjoenes, L.; Soederman, A.-L.

    2004-01-01

    In 2001 the Swedish Work Environment Authority asked five regional offices around the country; Falun, Malmoe, Vaexjoe, Umeaa and Oerebro, to measure radon in air in workplaces where water was likely to enhance radon levels indoors. Track etch detectors were used and placed in workplaces according to the SSI measurement protocol for determining the annual average radon concentration in homes. Rooms that are frequently used by employees were measured. The detectors were exposed between 1 to 3 months. 225 detectors were used in the project and analysed at the same laboratory. The results showed that the radon concentration in waterworks often is high. Measurements were made in 60 waterworks. Levels exceeding 1000 Bq/m 3 were found in 49 of them and levels exceeding 4000 Bq/m 3 were found in 21 waterworks. The variation between waterworks may be a result of the radon concentration in the raw water, the amount of radon gas escaping to the air when water is treated, the air exchange rate in the building and where the detectors were deployed. Measurements were made in 28 indoor swimming baths. The maximum level was 290 Bq/m 3 , but most concentrations were between 30 to 70 Bq/m 3 . The conclusion is that high radon levels do not seem to be a problem in indoor swimming baths. Maybe this is due to good ventilation or the fact that water often has been treated for radon before it is used in swimming pools. The results from measurement in food industries such as breweries showed no extreme radon levels except for a fish farm where levels over 1000 Bq/m 3 were measured in the farming room and 790 Bq/m 3 in the office. The radon concentrations in laundries were relatively low, between 30 and 170 Bq/m 3

  11. Characterization of a virulent Leptospira interrogans strain isolated from an abandoned swimming pool.

    Science.gov (United States)

    Forster, Karine M; Hartwig, Daiane D; Seixas, Fabiana K; McBride, Alan J A; Monte, Leonardo G; Recuero, Ana Lúcia C; Brod, Claudiomar S; Hartleben, Cláudia P; Amaral, Marta; Dellagostin, Odir A

    2013-01-01

    Pathogenic Leptospira spp. are the etiological agents of leptospirosis, an important disease of both humans and animals. In urban settings, L. interrogans serovars are the predominant cause of disease in humans. The purpose of this study was to characterize a novel Leptospira isolate recovered from an abandoned swimming pool. Molecular characterization through sequencing of the rpoB gene revealed 100% identity with L. interrogans and variable-number tandem-repeat (VNTR) analysis resulted in a banding pattern identical to L. interrogans serogroup Icterohaemorrhagiae, serovar Copenhageni or Icterohaemorrhagiae. The virulence of the strain was determined in a hamster model of lethal leptospirosis. The lethal dose 50% (LD50) was calculated to be two leptospires in female hamsters and a histopathological examination of infected animals found typical lesions associated with severe leptospirosis, including renal epithelium degeneration, hepatic karyomegaly, liver-plate disarray and lymphocyte infiltration. This highly virulent strain is now available for use in further studies, especially evaluation of vaccine candidates.

  12. Should children be SCUBA diving?: Cerebral arterial gas embolism in a swimming pool.

    Science.gov (United States)

    Johnson, Valerie; Adkinson, Cheryl; Bowen, Mariya; Ortega, Henry

    2012-04-01

    Cerebral arterial gas embolism (CAGE) is a well-known serious complication of self-contained breathing apparatus (SCUBA) diving. Most serious complications of SCUBA diving occur in adults because most of SCUBA divers are adults. However, young age is an independent risk factor for injury in SCUBA diving and shallow-water SCUBA diving is the riskiest environment for CAGE. We present a case of a 10-year-old boy who developed CAGE while taking SCUBA diving lessons in a university swimming pool. This case illustrates the potential danger of SCUBA diving for children who lack understanding of the physics of diving as well as the often unappreciated risk of shallow-water SCUBA diving. Our intent is to educate providers of primary care to children, so that they may appropriately advise parents about SCUBA diving, and to educate providers of emergency care to children, so that they will recognize this uncommon but serious emergency condition.

  13. Combined UV treatment and ozonation for the removal of by-product precursors in swimming pool water

    DEFF Research Database (Denmark)

    Cheema, Waqas Akram; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2017-01-01

    Both UV treatment and ozonation are used to reduce different types of disinfection by-products (DBPs) in swimming pools. UV treatment is the most common approach, as it is particularly efficient at removing combined chlorine. However, the UV treatment of pool water increases chlorine reactivity...... and the formation of chloro-organic DBPs such as trihalomethanes. Based on the similar selective reactivity of ozone and chlorine, we hypothesised that the created reactivity to chlorine, as a result of the UV treatment of dissolved organic matter in swimming pool water, might also be expressed as increased...... reactivity to ozone. Moreover, ozonation might saturate the chlorine reactivity created by UV treatment and mitigate increased formation of a range of volatile DBPs. We found that UV treatment makes pool water highly reactive to ozone. The subsequent reactivity to chlorine decreases with increasing ozone...

  14. Secondary formation of disinfection by-products by UV treatment of swimming pool water

    International Nuclear Information System (INIS)

    Spiliotopoulou, Aikaterini; Hansen, Kamilla M.S.; Andersen, Henrik R.

    2015-01-01

    Formation of disinfection by-products (DBPs) during experimental UV treatment of pool water has previously been reported with little concurrence between laboratory studies, field studies and research groups. In the current study, changes in concentration of seven out of eleven investigated volatile DBPs were observed in experiments using medium pressure UV treatment, with and without chlorine and after post-UV chlorination. Results showed that post-UV chlorine consumption increased, dose-dependently, with UV treatment dose. A clear absence of trihalomethane formation by UV and UV with chlorine was observed, while small yet statistically significant increases in dichloroacetonitrile and dichloropropanone concentrations were detected. Results indicate that post-UV chlorination clearly induced secondary formation of several DBPs. However, the formation of total trihalomethanes was no greater than what could be replicated by performing the DBP formation assay with higher chlorine concentrations to simulate extended chlorination. Post-UV chlorination of water from a swimming pool that continuously uses UV treatment to control combined chlorine could not induce secondary formation for most DBPs. Concurrence for induction of trihalomethanes was identified between post-UV chlorination treatments and simulated extended chlorination time treatment. Trihalomethanes could not be induced by UV treatment of water from a continuously UV treated pool. This indicates that literature reports of experimentally induced trihalomethane formation by UV may be a result of kinetic increase in formation by UV. However, this does not imply that higher trihalomethane concentrations would occur in pools that apply continuous UV treatment. The bromine fraction of halogens in formed trihalomethanes increased with UV dose. This indicates that UV removes bromine atoms from larger molecules that participate in trihalomethane production during post-UV chlorination. Additionally, no significant

  15. Destruction of disinfection byproducts and their precursors in swimming pool water by combined UV treatment and ozonation

    OpenAIRE

    Cheema, Waqas Akram; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    2016-01-01

    Both UV treatment and ozonation are used to reduce different types of disinfection byproducts (DBP) in swimming pools. UV treatment is most common as it is particularly efficient in removing the repulsive chlorine like smelling chloramines (combined chlorine). UV treatment of a pool water increased chlorine reactivity and formation of chlor-organic DBP such as trihalomethanes. Based on the similar selective reactivity of ozone and chlorine we hypothesized that the created reactivity towards c...

  16. Swimming

    Science.gov (United States)

    ... re just learning to swim, stay in the shallow end. Don't push or jump on others. ... and treatment, consult your doctor. © 1995- The Nemours Foundation. All rights reserved. Images provided by The Nemours ...

  17. Surveillance and Molecular Identification of Acanthamoeba and Naegleria Species in Two Swimming Pools in Alexandria University, Egypt

    Science.gov (United States)

    AL-HERRAWY, Ahmad Z.; KHALIL, Mahmoud I.; EL-SHERIF, Soheir S.; OMAR, Fatima A. E.; LOTFY, Wael M.

    2017-01-01

    Background: Swimming in contaminated water was reported to be associated with Acanthamoeba and N. fowleri human infections. The present study was carried out with the aim of isolation and identification of the different species of Acanthamoeba and Naegleria from two swimming pools in Alexandria University. Methods: Samples were collected from the swimming pools of Alexandria University Stadium and Faculty of Agriculture-Alexandria University during the period from May 2012 to April 2013. Results: Free-living amoebae were prevalent in the collected samples. Molecular characterization confirmed the identity of ten Acanthamoeba isolates and seven Naegleria isolates. Acanthamoeba T3, T4, T5, T11 and T15 genotypes were identified. Acanthamoeba T4 was the most prevalent genotype. Conclusion: The relatively high prevalence of Acanthamoeba, especially genotype T4, indicates the presence of a health hazard to swimmers particularly those wearing contact lenses. Naegleria fowleri was not found during the present study. PMID:28761479

  18. Surveillance and Molecular Identification of Acanthamoeba and Naegleria Species in Two Swimming Pools in Alexandria University, Egypt

    Directory of Open Access Journals (Sweden)

    Ahmad Z. AL-HERRAWY

    2017-06-01

    Full Text Available Background: Swimming in contaminated water was reported to be associated with Acanthamoeba and N. fowleri human infections. The present study was carried out with the aim of isolation and identification of the different species of Acanthamoeba and Naegleria from two swimming pools in Alexandria University. Methods: Samples were collected from the swimming pools of Alexandria University Stadium and Faculty of Agriculture-Alexandria University during the period from May 2012 to April 2013.Results: Free-living amoebae were prevalent in the collected samples. Molecular characterization confirmed the identity of ten Acanthamoeba isolates and seven Naegleria isolates. Acanthamoeba T3, T4, T5, T11 and T15 genotypes were identified. Acanthamoeba T4 was the most prevalent genotype.Conclusion: The relatively high prevalence of Acanthamoeba, especially genotype T4, indicates the presence of a health hazard to swimmers particularly those wearing contact lenses. Naegleria fowleri was not found during the present study. 

  19. Analysis of natural convection in volumetrically-heated melt pools

    International Nuclear Information System (INIS)

    Sehgal, B.R.; Dinh, T.N.; Nourgaliev, R.R.

    1996-12-01

    Results of series of studies on natural convection heat transfer in decay-heated core melt pools which form in a reactor lower plenum during the progression of a core meltdown accident are described. The emphasis is on modelling and prediction of turbulent heat transfer characteristics of natural convection in a liquid pool with an internal energy source. Methods of computational fluid dynamics, including direct numerical simulation, were applied for investigation

  20. Analysis of natural convection in volumetrically-heated melt pools

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, B.R.; Dinh, T.N.; Nourgaliev, R.R. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Nuclear Power Safety

    1996-12-01

    Results of series of studies on natural convection heat transfer in decay-heated core melt pools which form in a reactor lower plenum during the progression of a core meltdown accident are described. The emphasis is on modelling and prediction of turbulent heat transfer characteristics of natural convection in a liquid pool with an internal energy source. Methods of computational fluid dynamics, including direct numerical simulation, were applied for investigation. Refs, figs, tabs.

  1. Effect of ozonation of swimming pool water on formation of volatile disinfection by-products - A laboratory study

    DEFF Research Database (Denmark)

    Hansen, Kamilla Marie Speht; Spiliotopoulou, Aikaterini; Cheema, Waqas Akram

    2016-01-01

    dosage, however this decreased with subsequent treatments. For tap and polluted pool water, ozone reacted directly with the pollutants resulting in a short ozone half-life, removing reactivity towards chlorine oxidation and preventing TTHM production. Conversely for pool water samples, due to the long......) was observed to increase in pool water with ozone treatment. Thus, ozonation dosage regimes should be designed such that ozone mostly oxidizes fresh pollutants before chlorine is able to react with it.......Ozonation experiments were performed using unchlorinated tap water used for filling municipal swimming pools, actual pool water and pool water polluted by addition of fresh tap water and artificial body fluid to evaluate ozone kinetics and water quality effects on formation of volatile disinfection...

  2. Siloe, Osiris, and the future perspective of swimming-pool reactors; Siloe et Osiris

    Energy Technology Data Exchange (ETDEWEB)

    Chatoux, J.; Denielou, G.; Lerouge, B. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires; Kervenoael, O. de [Societe INDATOM (France)

    1964-07-01

    Siloe and Osiris are two new general purpose research reactors of the 'Commissariat a l'energie Atomique'. Siloe, located within the 'Centre d'Etudes Nucleaires' of Grenoble is a swimming pool reactor of the same type as Melusine and Triton. It operates, at a nominal power of 15 MW thermal and has reached the peak power of 20 MW thermal with two thirds of its cooling system working. The fast flux above 1 MeV, which is maximum at the center of the core at 15 MW thermal is 1,2. 10{sup 14}. The core, quite open, is downward cooled. Average specific power is 159 kW/l. Osiris is under construction at Saclay. Designed for 50 MW thermal, this reactor is upward cooled. The fast flux at the center of the core above 1 MeV is calculated to be 2, 5.10{sup 14}. The average designed specific power is 280 kW/l. A fixed zircaloy gamma shield makes a box round the core. Future perspectives open to non-pressurised swimming-pool reactors are examined. Ways are suggested for neutronic; thermal and shielding modifications which make possible further improvements in the performances and economy of these devices. (authors) [French] SILOE et OSIRIS sont deux nouvelles piles de recherche non specialisees du Commissariat a l'Energie Atomique. Installee au Centre de GRENOBLE, SILOE est une pile piscine derivee de MELUSINE et TRITON. Elle fonctionne a 15 MWt en regime nominal et a ete poussee a 20 MWt avec les 2/3 de sa refrigeration en route. Le flux rapide au dessus de 1 MeV maximum au centre du coeur a 15 MWt est de 1,2 10{sup 14}. Le coeur, entierement ouvert, est refroidi en sens descendant et la puissance specifique moyenne est 150 KW/l. OSIRIS est en construction a SACLAY. Prevue pour 50 MWt thermique, cette pile est au contraire refrigeree en sens ascendant. Le flux rapide au centre du coeur au dessus de 1 MeV est de 2,5 10{sup 14} calcules. La puissance specifique moyenne prevue est de 280 KW/l de coeur. Une protection gamma fixe en zircalloy forme

  3. Destruction of disinfection byproducts and their precursors in swimming pool water by combined UV treatment and ozonation

    DEFF Research Database (Denmark)

    Cheema, Waqas Akram; Kaarsholm, Kamilla Marie Speht; Andersen, Henrik Rasmus

    Both UV treatment and ozonation are used to reduce different types of disinfection byproducts (DBP) in swimming pools. UV treatment is most common as it is particularly efficient in removing the repulsive chlorine like smelling chloramines (combined chlorine). UV treatment of a pool water increased...... chlorine reactivity and formation of chlor-organic DBP such as trihalomethanes. Based on the similar selective reactivity of ozone and chlorine we hypothesized that the created reactivity towards chlorine by UV treatment of dissolved organic matter in pool water might also be expressed as an increased...... reactivity towards ozone and that ozonation might saturate the chlorine reactivity created by UV treatment and mitigate the increased DBP formation. By experimentally treating pool water samples, we found that UV treatment makes pool water highly reactive to ozone. The created reactivity towards chlorine...

  4. An innovative pool with a passive heat removal system

    International Nuclear Information System (INIS)

    Vitale Di Maio, Damiano; Naviglio, Antonio; Giannetti, Fabio; Manni, Fabio

    2012-01-01

    Heat removal systems are of primary importance in several industrial processes. As heat sink, a water pool or atmospheric air may be selected. The first solution takes advantage of high heat transfer coefficient with water but it requires active systems to maintain a constant water level; the second solution takes benefit from the unlimited heat removal capacity by air, but it requires a larger heat exchanger to compensate the lower heat transfer coefficient. In NPPs (nuclear power plants) during a nuclear reactor shutdown, as well as in some chemical plants to control runaway reactions, it is possible to use an innovative heat sink that joins the advantages of the two previous solutions. This solution is based on a special heat exchanger submerged in a water pool designed so that when heat removal is requested, active systems are not required to maintain the water level; due to the special design, when the pool is empty, atmospheric air becomes the only heat sink. The special heat exchanger design allows to have a heat exchanger without being oversized and to have a system able to operate for unlimited period without external interventions. This innovative system provides an economic advantage as well as enhanced safety features.

  5. Characterization of a virulent Leptospira interrogans strain isolated from an abandoned swimming pool

    Directory of Open Access Journals (Sweden)

    Karine M. Forster

    2013-01-01

    Full Text Available Pathogenic Leptospira spp. are the etiological agents of leptospirosis, an important disease of both humans and animals. In urban settings, L. interrogans serovars are the predominant cause of disease in humans. The purpose of this study was to characterize a novel Leptospira isolate recovered from an abandoned swimming pool. Molecular characterization through sequencing of the rpoB gene revealed 100% identity with L. interrogans and variable-number tandem-repeat (VNTR analysis resulted in a banding pattern identical to L. interrogans serogroup Icterohaemorrhagiae, serovar Copenhageni or Icterohaemorrhagiae. The virulence of the strain was determined in a hamster model of lethal leptospirosis. The lethal dose 50% (LD50 was calculated to be two leptospires in female hamsters and a histopathological examination of infected animals found typical lesions associated with severe leptospirosis, including renal epithelium degeneration, hepatic karyomegaly, liver-plate disarray and lymphocyte infiltration. This highly virulent strain is now available for use in further studies, especially evaluation of vaccine candidates.

  6. Detection and quantification of human adenovirus genomes in Acanthamoeba isolated from swimming pools

    Directory of Open Access Journals (Sweden)

    RODRIGO STAGGEMEIER

    2016-01-01

    Full Text Available ABSTRACT Acanthamoeba is the most common free-living environmental amoeba, it may serve as an important vehicle for various microorganisms living in the same environment, such as viruses, being pathogenic to humans. This study aimed to detect and quantify human adenoviruses (HAdV in Acanthamoebas isolated from water samples collected from swimming pools in the city of Porto Alegre, Southern Brazil. Free-living amoebae of the genus Acanthamoeba were isolated from water samples, and isolates (n=16 were used to investigate the occurrence of HAdVs. HAdV detection was performed by quantitative real-time polymerase chain reaction (qPCR. HAdVs were detected in 62.5% (10/16 of Acanthamoeba isolates, ranging from 3.24x103 to 5.14x105 DNA copies per milliliter of isolate. HAdV viral loads found in this study are not negligible, especially because HAdV infections are associated with several human diseases, including gastroenteritis, respiratory distress, and ocular diseases. These findings reinforce the concept that Acanthamoeba may act as a reservoir and promote HAdV transmission through water.

  7. Electromagnetic Interference from Swimming Pool Generator Current Causing Inappropriate ICD Discharges

    Directory of Open Access Journals (Sweden)

    Edward Samuel Roberto

    2017-01-01

    Full Text Available Electromagnetic interference (EMI includes any electromagnetic field signal that can be detected by device circuitry, with potentially serious consequences: incorrect sensing, pacing, device mode switching, and defibrillation. This is a unique case of extracardiac EMI by alternating current leakage from a submerged motor used to recycle chlorinated water, resulting in false rhythm detection and inappropriate ICD discharge. A 31-year-old female with arrhythmogenic right ventricular cardiomyopathy and Medtronic dual-chamber ICD placement presented after several inappropriate ICD shocks at the public swimming pool. Patient had never received prior shocks and device was appropriate at all regular follow-ups. Intracardiac electrograms revealed unique, high-frequency signals at exactly 120 msec suggestive of EMI from a strong external source of alternating current. Electrical artifact was incorrectly sensed as a ventricular arrhythmia which resulted in discharge. ICD parameters including sensing, pacing thresholds, and impedance were all normal suggesting against device malfunction. With device failure and intracardiac sources excluded, EMI was therefore strongly suspected. Avoidance of EMI source brought complete resolution with no further inappropriate shocks. After exclusion of intracardiac interference, device malfunction, and abnormal settings, extracardiac etiologies such as EMI must be thoughtfully considered and excluded. Elimination of inappropriate shocks is to “first, do no harm.”

  8. Prevalence of Ocular, Respiratory and Cutaneous Symptoms in Indoor Swimming Pool Workers and Exposure to Disinfection By-Products (DBPs

    Directory of Open Access Journals (Sweden)

    Guglielmina Fantuzzi

    2010-03-01

    Full Text Available The objective of this cross-sectional study was to investigate the prevalence of self-reported respiratory, ocular and cutaneous symptoms in subjects working at indoor swimming pools and to assess the relationship between frequency of declared symptoms and occupational exposure to disinfection by-products (DBPs. Twenty indoor swimming pools in the Emilia Romagna region of Italy were included in the study. Information about the health status of 133 employees was collected using a self-administered questionnaire. Subjects working at swimming pools claimed to frequently experience the following symptoms: cold (65.4%, sneezing (52.6%, red eyes (48.9% and itchy eyes (44.4%. Only 7.5% claimed to suffer from asthma. Red eyes, runny nose, voice loss and cold symptoms were declared more frequently by pool attendants (lifeguards and trainers when compared with employees working in other areas of the facility (office, cafe, etc.. Pool attendants experienced generally more verrucas, mycosis, eczema and rash than others workers; however, only the difference in the frequency of self-declared mycosis was statistically significant (p = 0.010. Exposure to DBPs was evaluated using both environmental and biological monitoring. Trihalomethanes (THMs, the main DBPs, were evaluated in alveolar air samples collected from subjects. Swimming pool workers experienced different THM exposure levels: lifeguards and trainers showed the highest mean values of THMs in alveolar air samples (28.5 ± 20.2 µg/m3, while subjects working in cafe areas (17.6 ± 12.1 µg/m3, offices (14.4 ± 12.0 µg/m3 and engine rooms (13.6 ± 4.4 µg/m3 showed lower exposure levels. Employees with THM alveolar air values higher than 21 µg/m3 (median value experienced higher risks for red eyes (OR 6.2; 95% CI 2.6–14.9, itchy eyes (OR 3.5; 95% CI 1.5–8.0, dyspnea/asthma (OR 5.1; 95% CI 1.0–27.2 and blocked nose (OR 2.2; 95% CI 1.0–4.7 than subjects with less exposure. This study confirms

  9. Heat transfer studies in pool fire environment

    International Nuclear Information System (INIS)

    Nitsche, F.

    1993-01-01

    A Type B package has to withstand severe thermal accident conditions. To calculate the temperature behaviour of such a package in a real fire environment, heat transfer parameters simulating the effect of the fire are needed. For studying such heat transfer parameters, a systematic programme of experimental and theoretical investigations was performed which was part of the IAEA Coordinated Research Programme (Nitsche and Weib 1990). The studies were done by means of small, unfinned and finned, steel model containers of simplified design in hydrocarbon fuel open fire tests. By using various methods, flame and container temperatures were measured and also container surface absorptivity before and after the test to study the effect of sooting and surface painting on heat transfer. Based on all these experimental data and comparative calculations, simplified, effective heat transfer parameters could be derived, simulating the effect of the real fire on the model containers. (J.P.N.)

  10. The Confluence of Naturalism and Postmodernism in Rose Tremain’s The Swimming Pool Season: a Post-War Feminist

    OpenAIRE

    Walezak, Emilie

    2017-01-01

    Cet article entend démontrer la vitalité de l’écriture réaliste dans le monde contemporain en prenant pour exemple le roman de Rose Tremain, The Swimming Pool Season, publié en 1985. Bien que condamné par la critique structuraliste et post-structuraliste des années 70 et 80 comme véhicule de valeurs bourgeoises conservatrices, le réalisme a su se renouveler en intégrant la problématique postmoderniste de la fragmentation de l’identité. Dans The Swimming Pool Season, les références intertextue...

  11. [Environmental surveillance of a sample of indoor swimming pools from Emilia Romagna region: microclimate characteristics and chemical parameters, particularly disinfection by products, in pool waters].

    Science.gov (United States)

    Fantuzzi, G; Righi, E; Predieri, G; Giacobazzi, P; Mastroianni, K; Aggazzotti, G

    2010-01-01

    The aim of the present study was to investigate the environmental and healthy aspects from a representative sample of indoor swimming pools located in the Emilia Romagna region. During the sampling sessions, the occupational environment was evaluated in terms of microclimate parameters and thermal comfort/discomfort conditions. Moreover the chemical risk was assessed by analyzing from the pool water the presence of disinfection by-products (DBPs), such as: trihalomethanes (THMs), haloacetic acids (HAAs), chlorite, chlorate and bromate. The analytical results are in agreement with the Italian legislation (Accordo Stato-Regioni; 2003) even if in some of the sampled indoor swimming pools, the dosed combined chlorine levels, were greater than the Italian limit. With the regard to the microclimate conditions evaluation, the considered thermal indices, Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD%), described a satisfactory occupational environment. Among DBPs, the THMs mean levels (41.4 +/- 30.0 microg/l) resulted close to the values of the current Italian drinking water legislation, and seem to not represent an health issue. The pool waters chlorate levels (range: 5 - 19537 microg/l) need further investigations as recent epidemiological studies on drinking water hypothesized a potential genotoxicity effect of these compounds which are involved in cellular oxidative processes.

  12. Influence of physical activity in the intake of trihalomethanes in indoor swimming pools.

    Science.gov (United States)

    Marco, Esther; Lourencetti, Carolina; Grimalt, Joan O; Gari, Mercè; Fernández, Pilar; Font-Ribera, Laia; Villanueva, Cristina M; Kogevinas, Manolis

    2015-07-01

    This study describes the relationship between physical activity and intake of trihalomethanes (THMs), namely chloroform (CHCl3), bromodichloromethane (CHCl2Br), dibromochloromethane (CHClBr2) and bromoform (CHBr3), in individuals exposed in two indoor swimming pools which used different disinfection agents, chlorine (Cl-SP) and bromine (Br-SP). CHCl3 and CHBr3 were the dominant compounds in air and water of the Cl-SP and Br-SP, respectively. Physical exercise was assessed from distance swum and energy expenditure. The changes in exhaled breath concentrations of these compounds were measured from the differences after and before physical activity. A clear dependence between distance swum or energy expenditure and exhaled breath THM concentrations was observed. The statistically significant relationships involved higher THM concentrations at higher distances swum. However, air concentration was the major factor determining the CHCl3 and CHCl2Br intake in swimmers whereas distance swum was the main factor for CHBr3 intake. These two causes of THM incorporation into swimmers concurrently intensify the concentrations of these compounds into exhaled breath and pointed to inhalation as primary mechanism for THM uptake. Furthermore, the rates of THM incorporation were proportionally higher as higher was the degree of bromination of the THM species. This trend suggested that air-water partition mechanisms in the pulmonary system determined higher retention of the THM compounds with lower Henry's Law volatility constants than those of higher constant values. Inhalation is therefore the primary mechanisms for THM exposure of swimmers in indoor buildings. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Removal of haloacetic acids from swimming pool water by reverse osmosis and nanofiltration.

    Science.gov (United States)

    Yang, Linyan; She, Qianhong; Wan, Man Pun; Wang, Rong; Chang, Victor W-C; Tang, Chuyang Y

    2017-06-01

    Recent studies report high concentrations of haloacetic acids (HAAs), a prevalent class of toxic disinfection by-products, in swimming pool water (SPW). We investigated the removal of 9 HAAs by four commercial reverse osmosis (RO) and nanofiltration (NF) membranes. Under typical SPW conditions (pH 7.5 and 50 mM ionic strength), HAA rejections were >60% for NF270 with molecular weight cut-off (MWCO) equal to 266 Da and equal or higher than 90% for XLE, NF90 and SB50 with MWCOs of 96, 118 and 152 Da, respectively, as a result of the combined effects of size exclusion and charge repulsion. We further included 7 neutral hydrophilic surrogates as molecular probes to resolve the rejection mechanisms. In the absence of strong electrostatic interaction (e.g., pH 3.5), the rejection data of HAAs and surrogates by various membranes fall onto an identical size-exclusion (SE) curve when plotted against the relative-size parameter, i.e., the ratio of molecular radius over membrane pore radius. The independence of this SE curve on molecular structures and membrane properties reveals that the relative-size parameter is a more fundamental SE descriptor compared to molecular weight. An effective molecular size with the Stokes radius accounting for size exclusion and the Debye length accounting for electrostatic interaction was further used to evaluate the rejection. The current study provides valuable insights on the rejection of trace contaminants by RO/NF membranes. Copyright © 2017. Published by Elsevier Ltd.

  14. Leidenfrost drops on a heated liquid pool

    Science.gov (United States)

    Maquet, L.; Sobac, B.; Darbois-Texier, B.; Duchesne, A.; Brandenbourger, M.; Rednikov, A.; Colinet, P.; Dorbolo, S.

    2016-09-01

    We show that a volatile liquid drop placed at the surface of a nonvolatile liquid pool warmer than the boiling point of the drop can be held in a Leidenfrost state even for vanishingly small superheats. Such an observation points to the importance of the substrate roughness, negligible in the case considered here, in determining the threshold Leidenfrost temperature. A theoretical model based on the one proposed by Sobac et al. [Phys. Rev. E 90, 053011 (2014), 10.1103/PhysRevE.90.053011] is developed in order to rationalize the experimental data. The shapes of the drop and of the liquid substrate are analyzed. The model notably provides scalings for the vapor film thickness profile. For small drops, these scalings appear to be identical to the case of a Leidenfrost drop on a solid substrate. For large drops, in contrast, they are different, and no evidence of chimney formation has been observed either experimentally or theoretically in the range of drop sizes considered in this study. Concerning the evaporation dynamics, the radius is shown to decrease linearly with time whatever the drop size, which differs from the case of a Leidenfrost drop on a solid substrate. For high superheats, the characteristic lifetime of the drops versus the superheat follows a scaling law that is derived from the model, but, at low superheats, it deviates from this scaling by rather saturating.

  15. Diarrhea and Swimming

    Science.gov (United States)

    ... Pool What to Do if You Have Diarrhea Diarrhea and Swimming Diarrhea and swimming don’t mix! ... small amount of pool water to become infected. Diarrhea and Spreading Illness at the Pool Infectious diarrhea ...

  16. Surface wettability and subcooling on nucleate pool boiling heat transfer

    Science.gov (United States)

    Suroto, Bambang Joko; Kohno, Masamichi; Takata, Yasuyuki

    2018-02-01

    The effect of varying surface wettabilities and subcooling on nucleate pool boiling heat transfer at intermediate heat flux has been examined and investigated. The experiments were performed using pure water as the working fluid and subcooling ranging from 0, 5 and 10 K, respectively. The three types of heat transfer block were used that are bare surface/hydrophilic (polished copper), superhydrophilic/TiO2-coated on copper and hydrophobic/PTFE surface. The experimental results will be examined by the existing model. The results show that the heat transfer performance of surfaces with PTFE coating is better at low heat flux. While for an intermediate heat flux, superhydrophilic surface (TiO2) is superior compared to hydrophilic and hydrophobic surfaces. It is observed that the heat transfer performance is decreasing when the sub cooling degree is increased.

  17. Burnout in boiling heat transfer. part I: pool boiling systems

    International Nuclear Information System (INIS)

    Bergles, A.E.

    1977-01-01

    Recent experimental and analytical developments in pool-boiling burnout are reviewed, and results are summarized that clarify the dependence of critical heat flux on heater geometry and fluid properties. New analytical interpretations of burnout are discussed, and the effects of surface condition, aging, acceleration, and transient heating (or cooling) are described. The relation of sound to burnout and new techniques for stabilizing electric heaters at burnout are also considered

  18. Pump/heat exchanger assembly for pool-type reactor

    International Nuclear Information System (INIS)

    Nathenson, R.D.; Slepian, R.M.

    1989-01-01

    This patent describes a heat exchanger and pump assembly for transferring thermal energy from a heated, first electrically conductive fluid to a pumped, second electrically conductive fluid and for transferring internal energy from the pumped, second electrically conductive fluid to the first electrically conductive fluid, the assembly adapted to be disposed within a pool of the first electrically conductive fluid and comprising: a heat exchanger comprising means for defining a first annularly shaped cavity for receiving a flow of the second electrically conductive fluid and a plurality of tubes disposed within the cavity, whereby the second electrically conductive fluid in the cavity is heated, each of the tubes having an input and an output end. The input ends being disposed at the top of the heat exchanger for receiving from the pool a flow of the first electrically conductive fluid therein. The output ends being disposed at the bottom of and free of the cavity defining means for discharging the first electrically conductive fluid directly into the pool; a pump disposed beneath the heat exchanger and comprised of a plurality of flow couplers disposed in a circular array, each flow coupler comprised of a pump duct for receiving the first electrically conductive fluid and a generator duct for receiving the second electrically conductive fluid

  19. An Architectural Self - Criticism: The Accessibility Analysis of Berlika Park Swimming Pool

    Directory of Open Access Journals (Sweden)

    Özlem Demirkan

    2016-12-01

    Full Text Available Urban designers and architects have to clearly understand the physical features and needs of the people they are designing for. In the designing process fields such as   anthropometry, biomechanics, ergonomics, biology and physics require scientific verification to architects. But it can easily be forgotten that there are physically-challenged persons. All users experience any place by using their ability to move and perceive. If designers don’t take into account the special circumstances in the design process for physically-challenged persons, the accessibility of the place becomes impossible. At the same time a sustainable and an accessible place is truly a sign of urban rights being recognized. In this context, human rights are not only important for disciplines such as law, sociology, psychology and political sciences but also they must be important for design disciplines such as architecture, urban and interior design. This research based on the rights to exercise for physically-challenged persons aims to analyze the accessibility of the place. I was a member of the design team and today an active user of the facility-Berlika Park Swimming Pool-chosen for this study. Photographs were taken of different areas of the facility not compliant with TSE standards -TS9111 - TS 12576. Within this context, the structure was examined in terms of mobility constraints under the titles of accessible route, the arrangement of immediate surroundings of the building, arrangement of the entrance of the building, arrangement of the accessibility inside the building, signs, elevators, and fire emergency alert systems. The problematic areas of the building were identified and analyzed. This research aims to make the building more accessible place and a new modification project is being planned. But it is necessary to examine the building or the environment during its design process and solve the problems without the need of renovation project. The design

  20. Gravity and Heater Size Effects on Pool Boiling Heat Transfer

    Science.gov (United States)

    Kim, Jungho; Raj, Rishi

    2014-01-01

    The current work is based on observations of boiling heat transfer over a continuous range of gravity levels between 0g to 1.8g and varying heater sizes with a fluorinert as the test liquid (FC-72/n-perfluorohexane). Variable gravity pool boiling heat transfer measurements over a wide range of gravity levels were made during parabolic flight campaigns as well as onboard the International Space Station. For large heaters and-or higher gravity conditions, buoyancy dominated boiling and heat transfer results were heater size independent. The power law coefficient for gravity in the heat transfer equation was found to be a function of wall temperature under these conditions. Under low gravity conditions and-or for smaller heaters, surface tension forces dominated and heat transfer results were heater size dependent. A pool boiling regime map differentiating buoyancy and surface tension dominated regimes was developed along with a unified framework that allowed for scaling of pool boiling over a wide range of gravity levels and heater sizes. The scaling laws developed in this study are expected to allow performance quantification of phase change based technologies under variable gravity environments eventually leading to their implementation in space based applications.

  1. Chemical Safety Alert: Safe Storage and Handling of Swimming Pool Chemicals

    Science.gov (United States)

    Hazards of pool water treatment and maintenance chemicals (e.g., chlorine), and the protective measures pool owners should take to prevent fires, toxic vapor releases, and injuries. Triggered by improper wetting, mixing, or self-reactivity over time.

  2. Evaluation of biological and physico-chemical quality of public swimming pools, Hamadan (Iran

    Directory of Open Access Journals (Sweden)

    Edris Hoseinzadeh

    2013-01-01

    Conclusion: As results showed the residual chlorine in pools water was lower than standard level and as regard to microbial contamination in pool water, it can be concluded that the disinfection system has been impaired.

  3. UV filters interaction in the chlorinated swimming pool, a new challenge for urbanization, a need for community scale investigations.

    Science.gov (United States)

    Sharifan, Hamidreza; Klein, David; Morse, Audra N

    2016-07-01

    Sunscreen products and some personal care products contain the Ultraviolet (UV) chemical filters, which are entering the surface water. Public concerns about secondary effects of these compounds are growing because of the contamination of the aquatic environment that may reach to potentially toxic concentration levels. This article highlights the reaction of certain UV filters with hypochlorite disinfectant in the presence of sunlight. Due to urbanization and industrialization, use of outdoor plastic swimming pools is increasing. The relatively smaller volume of these pools compared to larger pools may increase the concentration of the UV filters in the pool and their potential interactions with materials of human origin (urine, sweat, cosmetics, skin cells, and hair) to the levels of toxicity concerns for children through the creation of disinfection by products (DBP). Based on our analysis, the minimum concentration levels of 2.85, 1.9, 1.78 and 0.95g/L, respectively, for EHMC, OC, 4-MBC and BP3 UV filters in children pools are predicted. Therefore, this article calls for an urgent investigation of potential toxic effects of the UV filters, the creation of DBPs and their subsequent impacts on human health. Published by Elsevier Inc.

  4. Heated jackets and dryland-based activation exercises used as additional warm-ups during transition enhance sprint swimming performance.

    Science.gov (United States)

    McGowan, Courtney J; Thompson, Kevin G; Pyne, David B; Raglin, John S; Rattray, Ben

    2016-04-01

    The lengthy competition transition phases commonly experienced by competitive swimmers may mitigate the benefits of the pool warm-up. To combat this, we examined the impact of additional passive and active warm-up strategies on sprint swimming performance. Counterbalanced, repeated-measures cross-over study. Sixteen junior competitive swimmers completed a standardised pool warm-up followed by a 30min transition and 100m freestyle time-trial. Swimmers completed four different warm-up strategies during transition: remained seated wearing a conventional tracksuit top and pants (Control), wore an insulated top with integrated heating elements (Passive), performed a 5min dryland-based exercise circuit (Dryland), or a combination of Passive and Dryland (Combo). Swimming time-trial performance, core and skin temperature and perceptual variables were monitored. Time variables were normalised relative to Control. Both Combo (-1.05±0.26%; mean±90% confidence limits, p=0.00) and Dryland (-0.68±0.34%; p=0.02) yielded faster overall time-trial performances, with start times also faster for Combo (-0.37±0.07%; p=0.00) compared to Control. Core temperature declined less during transition with Combo (-0.13±0.25°C; p=0.01) and possibly with Dryland (-0.24±0.13°C; p=0.09) compared to Control (-0.64±0.16°C), with a smaller reduction in core temperature related to better time-trial performance (R(2)=0.91; p=0.04). Dryland-based exercise circuits completed alone and in combination with the application of heated tracksuit jackets during transition can significantly improve sprint swimming performance. Attenuation in the decline of core temperature and a reduction in start time appear as likely mechanisms. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  5. Bubble formation during drop impact on a heated pool

    Science.gov (United States)

    Tian, Yuansi; Alhazmi, Muath; Kouraytem, Nadia; Thoroddsen, Sigurdur

    2017-11-01

    Ultra high-speed video imaging, at up to 200 kfps, is used to investigate a drop impinging onto a high temperature pool. The room-temperature perfluorohexane drop, which has a boiling temperature as low as 56 °C impacts on the soybean oil pool heated up to around 200 °C, which is overwhelmingly higher than the boiling temperature of the drop. The bottom of the drop is therefore covered by a layer of vapor which prevents contact between the two immiscible liquid surfaces, akin to the Leidenfrost effect However, as the pool temperature is reduced, one starts seeing contact and the dynamics transition into the vapor explosion regime. At the boundary of this regime we observe some entrapment of scattered or a toroidal ring of small bubbles. Experimental video data will be presented to show this novel phenomenon and explain how these bubbles are formed and evolve.

  6. ‘Right now, Sophie *swims in the pool?!’: Brain potentials of grammatical aspect processing

    Directory of Open Access Journals (Sweden)

    Monique eFlecken

    2015-11-01

    Full Text Available We investigated whether brain potentials of grammatical aspect processing resemble semantic or morpho-syntactic processing, or whether they instead are characterized by an entirely distinct pattern in the same individuals. We studied aspect from the perspective of agreement between the temporal information in the context (temporal adverbials, e.g., Right now and a morpho-syntactic marker of grammatical aspect (e.g., progressive is swimming. Participants read questions providing a temporal context that was progressive (What is Sophie doing in the pool right now? or habitual (What does Sophie do in the pool every Monday?. Following a lead-in sentence context such as Right now, Sophie…, we measured ERPs time-locked to verb phrases in four different conditions, e.g., (a is swimming (control; (b *is cooking (semantic violation; (c *are swimming (morpho-syntactic violation; or (d?swims (aspect mismatch; …in the pool. The collected ERPs show typical N400 and P600 effects for semantics and morpho-syntax, while aspect processing elicited an Early Negativity (250-350 ms. The aspect-related Negativity was short-lived and had a central scalp distribution with an anterior onset. This differentiates it not only from the semantic N400 effect, but also from the typical (LAN (Left Anterior Negativity, that is frequently reported for various types of agreement processing. Moreover, aspect processing was not accompanied by a clear P600 modulation.We argue that the specific context for each item in this experiment provided a trigger for agreement checking with temporal information encoded on the verb, i.e., morphological aspect marking. The aspect-related Negativity obtained for aspect agreement mismatches reflects a violated expectation concerning verbal inflection (in the example above, the expected verb phrase was Sophie is X-ing rather than Sophie X-s in condition d. The absence of an additional P600 for aspect processing suggests that the mismatch did not

  7. Heat transfer characteristics around a single heated rod immersed in sodium pool with gas jet injection

    International Nuclear Information System (INIS)

    Hideto Niikura; Kazuo Soga; Ken-ichiro Sugiyama; Akira Yamaguchi

    2005-01-01

    In a steam generator using liquid sodium, water intensely reacts with sodium when it leaks out from a heat transfer tube. It is important to evaluate the influence of sodium-water reaction to surrounding tubes and the shell. Hence, it has been desired to develop the simulation code for the evaluation of sodium-water reaction. From this viewpoint, the Japan Nuclear Cycle is now developing the SERAPHIM code. We reported a preliminary study to establish an experimental method for a single heated rod immersed in sodium pool with steam jet impingement planned in the near future as well as to obtain a preliminary data to verify the adequacy of SERAPHIM code. We first measured local and mean heat transfer coefficients around a horizontal single heated rod immersed in a water pool and a sodium pool with a limited volume in the experimental apparatus. It was confirmed that the mean heat transfer coefficients fairly agreed with the existing data for natural convection in water and sodium. Secondary we measured local and mean heat transfer coefficients around a horizontal single heated rod with Ar gas jet impingement immersed in the limited water pool and in the limited sodium pool. It was clearly observed that the local heat transfer coefficients in the sodium pool keep almost the same values in every angle regardless of increase in Ar gas jet velocity varied from about 8.7m/s to about 78m/s. On the other hand, it was confirmed in the water pool that local heat transfer coefficients on the forward stagnation side exposed in the Ar gas jet impingement increase with increasing the jet velocity while the local heat transfer coefficients on the opposite surface keep almost same values regardless of increase in the velocity. (authors)

  8. Experimental study on heat pipe heat removal capacity for passive cooling of spent fuel pool

    International Nuclear Information System (INIS)

    Xiong, Zhenqin; Wang, Minglu; Gu, Hanyang; Ye, Cheng

    2015-01-01

    Highlights: • A passively cooling SFP heat pipe with an 8.2 m high evaporator was tested. • Heat removed by the heat pipe is in the range of 3.1–16.8 kW. • The heat transfer coefficient of the evaporator is 214–414 W/m 2 /K. • The heat pipe performance is sensitive to the hot water temperature. - Abstract: A loop-type heat pipe system uses natural flow with no electrically driven components. Therefore, such a system was proposed to passively cool spent fuel pools during accidents to improve nuclear power station safety especially for station blackouts such as those in Fukushima. The heat pipe used for a spent fuel pool is large due to the spent fuel pool size. An experimental heat pipe test loop was developed to estimate its heat removal capacity from the spent fuel pool during an accident. The 7.6 m high evaporator is heated by hot water flowing vertically down in an assistant tube with a 207-mm inner diameter. R134a was used as the potential heat pipe working fluid. The liquid R134a level was 3.6 m. The tests were performed for water velocities from 0.7 to 2.1 × 10 −2 m/s with water temperatures from 50 to 90 °C and air velocities from 0.5 m/s to 2.5 m/s. The results indicate significant heat is removed by the heat pipe under conditions that may occur in the spent fuel pool

  9. Concentrations of disinfection by-products in swimming pool following modifications of the water treatment process: An exploratory study.

    Science.gov (United States)

    Tardif, Robert; Rodriguez, Manuel; Catto, Cyril; Charest-Tardif, Ginette; Simard, Sabrina

    2017-08-01

    The formation and concentration of disinfection by-products (DBPs) in pool water and the ambient air vary according to the type of water treatment process used. This exploratory study was aimed at investigating the short-term impact of modifications of the water treatment process on traditional DBP levels (e.g., trihalomethanes (THMs), chloramines) and emerging DBPs (e.g., Halonitromethanes, Haloketones, NDMA) in swimming pool water and/or air. A sampling program was carried to understand the impact of the following changes made successively to the standard water treatment process: activation of ultraviolet (UV) photoreactor, halt of air stripping with continuation of air extraction from the buffer tank, halt of air stripping and suppression of air extraction from the buffer tank, suppression of the polyaluminium silicate sulfate (PASS) coagulant. UV caused a high increase of Halonitromethanes (8.4 fold), Haloketones (2.1 fold), and THMs in the water (1.7 fold) and, of THMs in the air (1.6 fold) and contributed to reducing the level of chloramines in the air (1.6 fold) and NDMA in the water (2.1 fold). The results highlight the positive impact of air stripping in reducing volatile contaminants. The PASS did not change the presence of DBPs, except for the THMs, which decrease slightly with the use of this coagulant. This study shows that modifications affecting the water treatment process can rapidly produce important and variable impacts on DBP levels in water and air and suggests that implementation of any water treatment process to reduce DBP levels should take into account the specific context of each swimming pool. Copyright © 2017. Published by Elsevier B.V.

  10. Microbiological quality of swimming-pool waters in the province of Badajoz (Spain); Calidad microbiologica de las aguas de piscina en la provinca de Badajoz

    Energy Technology Data Exchange (ETDEWEB)

    Villalba Doblas, A. M.; Ambel Carracedo, M. P.; Cobos Rodriguez, J. G.

    2006-07-01

    The object of the actual work is to evaluate the microbiological quality of swimming pool waters in the province of Badajoz, 79 samples in 33 cities, according to criteria required by the Decreto 54/2002 of the Comunidad Autonoma of Extremadura. the work describes the possible origins of the pollution in the swimming-pool waters and the risks. The parameters analyzed were Termotolerant Coliforms, Faecal streptococci, S. aureus, P. aerogenes, Sulphate reducing bacteria and Salmonella spp. Results show that 62% of these fulfil microbiological quality criteria. the presence of Sulphate reducing bacteria was found in 24% of the samples, and P. aerogenes was detected in 16% of them. (Author) 20 refs.

  11. Jump if you can't take the heat: three escape gaits of Paramecium swimming

    Science.gov (United States)

    Baroud, Charles N.; Hamel, Amandine; Fisch, Cathy; Combettes, Laurent; Dupuys-Williams, Pascale

    2010-11-01

    Paramecium is able to swim at velocities reaching several times its body size per second, by beating its thousands of cilia in an organized fashion. Here we show that Paramecium has in fact three distinct swimming gaits to escape from an aggression in the form of localized heating, depending on the magnitude of the aggression: For a weak agression, normal swimming is sufficient and produces a steady swimming velocity through cilia beating. As the heating amplitude is increased, a higher acceleration and faster swimming are achieved through synchronized beating of the cilia, which later give way to the usual metachronal waves. The synchronized beating yields high initial accelerations but requires the cell to coast through the synchrnized recovery. Finally, escape from a life-threatening agression is achieved by a "jumping" gait which does not rely on the cilia but is achieved from the explosive release of a rod-like organelles in the direction of the hot spot. Measurements through high-speed video explain the role of these rods in defending Paramecium. They also show that the zero-Reynolds number assumption is unverified in most cases.

  12. Evaluation of LOCA in a swimming-pool type reactor using the 3D-AIRLOCA code

    International Nuclear Information System (INIS)

    Nagler, A.; Gilat, J.; Hirshfeld, H.

    1991-01-01

    The 3D-AIRLOCA code was used to calculate core temperature evolution curves in the wake of a full LOCA in a swimming pool type reactor, resulting in complete core exposure and dryout within about 1000 sec of the initiating event. The results show that fuel integrity loss thresholds (450 C for softening and 650 C for melting) are reached and exceeded over large fractions of the core at power levels as low as 2 MW. At 4.5 MW, the softening threshold is reached even when the accident occurs up to 12 hours after reactor shutdown for continuous operation, and up to 2 hrs after shutdown for intermittent (6 hrs/day, 4 days a week) operation. The situation is even more severe in blockage cases, when the air flow through the core is blocked by residual water at the grid plate level. It is concluded that substantial fission product releases are quite likely in this class of accidents. (orig.)

  13. Evaluation of LOCA in a swimming-pool type reactor using the 3D-AIRLOCA code

    International Nuclear Information System (INIS)

    Nagler, A.; Gilat, J.; Hirshfeld, H.

    1991-01-01

    The 3D-AIRLOCA code was used to calculate core temperature evolution curves in the wake of a full LOCA in a swimming pool type reactor, resulting in complete core exposure and dryout within about 1000 sec of the initiating event. The results show that fuel integrity loss thresholds (450 C for softening and 650 C for melting) are reached and exceeded over large fractions of the core at powr levels as low as 2 MW. At 4.5 MW, the softening threshold is reached even when the accident occurs up to 12 hours after reactor shutdown for continuous operation, and up to 2 hrs after shutdown for intermittent (6 hrs/day, 4 days a week) operation. The situation is even more severe in blockage cases, when the air flow through the core is blocked by residual water at the grid plate level. It is concluded that substantial fission product releases are quite likely in this class of accidents. (orig.)

  14. Determination of neutron energy spectrum at a pneumatic rabbit station of a typical swimming pool type material test research reactor

    International Nuclear Information System (INIS)

    Malkawi, S.R.; Ahmad, N.

    2002-01-01

    The method of multiple foil activation was used to measure the neutron energy spectrum, experimentally, at a rabbit station of Pakistan Research Reactor-1 (PARR-1), which is a typical swimming pool type material test research reactor. The computer codes MSITER and SANDBP were used to adjust the spectrum. The pre-information required by the adjustment codes was obtained by modelling the core and its surroundings in three-dimensions by using the one dimensional transport theory code WIMS-D/4 and the multidimensional finite difference diffusion theory code CITATION. The input spectrum covariance information required by MSITER code was also calculated from the CITATION output. A comparison between calculated and adjusted spectra shows a good agreement

  15. On-site releases of noble gases and iodine in the event of core meltdown in a swimming pool reactor

    International Nuclear Information System (INIS)

    Montaignac, E. de.

    1976-10-01

    Research aimed at defining a standard model accident for swimming pool type reactors, has led to the adoption to the so-called BORAX accident which involves complete meltdown of the reactor core. This type of accident-an accident related to dimensional problems- is useful for calculations concerning reactor components which have to withstand the mechanical forces resulting from the accident. A study of the radiobiological consequences of this type of accident, involving the entire reactor core, required research to determine as accurately as possible how the iodine, noble gases and solid fission products are distributed between the melted core and the site. The joint document in the annexure served as the basis for discussion at the meeting (BEVS/SESR) on 9th March 1973, at which the SESR set the standard parameter values to be used for estimating fission product distributions on the site. (author)

  16. Numerical prediction of nucleate pool boiling heat transfer coefficient under high heat fluxes

    Directory of Open Access Journals (Sweden)

    Pezo Milada L.

    2016-01-01

    Full Text Available This paper presents CFD (Computational Fluid Dynamics approach to prediction of the heat transfer coefficient for nucleate pool boiling under high heat fluxes. Three-dimensional numerical simulations of the atmospheric saturated pool boiling are performed. Mathematical modelling of pool boiling requires a treatment of vapor-liquid two-phase mixture on the macro level, as well as on the micro level, such as bubble growth and departure from the heating surface. Two-phase flow is modelled by the two-fluid model, which consists of the mass, momentum and energy conservation equations for each phase. Interface transfer processes are calculated by the closure laws. Micro level phenomena on the heating surface are modelled with the bubble nucleation site density, the bubble resistance time on the heating wall and with the certain level of randomness in the location of bubble nucleation sites. The developed model was used to determine the heat transfer coefficient and results of numerical simulations are compared with available experimental results and several empirical correlations. A considerable scattering of the predictions of the pool boiling heat transfer coefficient by experimental correlations is observed, while the numerically predicted values are within the range of results calculated by well-known Kutateladze, Mostinski, Kruzhilin and Rohsenow correlations. The presented numerical modeling approach is original regarding both the application of the two-fluid two-phase model for the determination of heat transfer coefficient in pool boiling and the defined boundary conditions at the heated wall surface. [Projekat Ministarstva nauke Republike Srbije, br. 174014

  17. The risk of contracting infectious diseases in public swimming pools: a review

    Directory of Open Access Journals (Sweden)

    Zsófia Barna

    2012-12-01

    Full Text Available A review of pathogenic microorganisms presenting risk of infection in pool based artificial recreational water venues is extracted from the available scientific literature. The microorganisms are grouped both according to their way of spread and their survival and growth strategies and their characteristics relevant for the pool and spa based recreation are discussed. In order to put the proposed risks on a solid basis, among others a ten year excerpt of the waterborne disease statistics of the Centers for Disease Control and Prevention (CDC is used throughout the article.

  18. Maintenance operation by divers on a swimming-pool type reactor (Osiris, CEN Saclay). Technical and medical prevention: an example of multidisciplinary ergonomic step

    International Nuclear Information System (INIS)

    Arnould, C.; Martin, L.

    1979-01-01

    Maintenance works in a swimming-pool reactor was performed by a team of divers. A multidisciplinary ergonomic study had previously defined the working procedure. The ergonomic approach is analysed. The divers' working techniques are described. After work, medical tests showed that previsions were verified and proved the methods as safe. This technique by divers' interventions should open new possibilities in nuclear industry [fr

  19. Heat transfer coefficient in pool boiling for an electrically heated tube at various inclinations

    International Nuclear Information System (INIS)

    Fahmy, A.S.A.; Mariy, A.H.; Mahmoud, S.I.; Ibrahim, N.A.

    1987-01-01

    An experimental investigation is carried out study the behaviour of heat transfer in pool boiling from a vertical and inclined heated tube at atmospheric pressure. An imperial correlation joining the different parameters affecting the heat transfer coefficient in pool boiling for an electrically heated tube at various inclinations is developed. Two test sections (zircaloy-4 and stainless steel) of 16 n n outer diameter and 120 nm length are investigated. Four levels of heat flux are used for heating the two lest sections (e.g. 381, 518, 721 and 929 k.watt/n 2). The maximum surface temperature achieved is 146.5 degree c for both materials, and the maximum bulk temperature is 95 degree C. It is found that the average heat transfer coefficient is inversely proportional with heated length l, where it reaches a constant value in the horizontal position. The heat transfer coefficient curves at various inclinations with respect to the heated tube length pass around one point which is defined as limit length

  20. Studies of heat-transfer in the crucible pool with the heat of the electron gun

    International Nuclear Information System (INIS)

    Zhu Yiming; Wang Dewu

    2000-01-01

    It is important for the recycle of uranium to increase the production of uranium metal evaporation by the electron gun with high temperature in AVLIS. To decrease the pollution of impurity and the erosion of the crucible caused by the molten uranium, the heat-transfer character of the crucible pool with the solid and liquid interface is studied by solving the Navier-Stocks equation and the energy equation according to the practice of the uranium recycling system. The research emphasizes on the relation between the heat-transfer character and the interface geometry, the crucible height, the heat-conducting factor, the parameter of the electron gun. All the studies show more about the heat-transfer character of the pool and give more parameter for the design of the crucible

  1. Study of Microbial Contamination of the Public Swimming Pools with Escherichia coli and Pseudomonas aeruginosa and Their Physical Parameters in Kermanshah, Iran

    Directory of Open Access Journals (Sweden)

    Afsaneh Haghmorad Korasti

    2016-09-01

    Full Text Available Background and Objectives: Public swimming pools' waters are contaminated with a wide variety of pathogenic microorganisms and are a suitable environment for transmission of different diseases. The aim of this study was to investigate the microbial contamination of the public swimming pools' waters with Escherichia coli and Pseudomonas aeruginosa and to determine certain parameters such as residual chlorine, pH, temperature and turbidity in these pools' waters in Kermanshah. In this descriptive, cross-sectional study, 129 water samples were taken from all active pools in Kermanshah and their bacteriologic and physicochemical properties were investigated. Phosphatase alkaline (PHO-A gene was used for molecular confirmation of E. coli isolates, and exotoxin A (ETA gene in PCR was employed to confirm pathogenicity of P. aeruginosa isolates. Data were analyzed by chi-square and t-test. p0.05. Conclusion: The results of this study indicated that appropriate amount of residual chlorine caused reduction in microbial contamination in the public swimming pools' waters in Kermanshah.

  2. Heat and Fission Product Transport in a Molten U-Zr-O Pool With Crust

    International Nuclear Information System (INIS)

    Yun, J.I.; Suh, K.Y.; Kang, C.S.

    2002-01-01

    Heat transfer and fluid flow in a molten pool are influenced by internal volumetric heat generated from the radioactive decay of fission product species retained in the pool. The pool superheat is determined based on the overall energy balance that equates the heat production rate to the heat loss rate. Decay heat of fission products in the pool was estimated by product of the mass concentration and energy conversion factor of each fission product. For the calculation of heat generation rate in the pool, twenty-nine elements were chosen and classified by their chemical properties. The mass concentration of a fission product is obtained from released fraction and the tabular output of the ORIGEN 2 code. The initial core and pool inventories at each time can also be estimated using ORIGEN 2. The released fraction of each fission product is calculated based on the bubble dynamics and mass transport. Numerical analysis was performed for the TMI-2 accident. The pool is assumed to be a partially filled hemispherical geometry and the change of pool geometry during the numerical calculation was neglected. Results of the numerical calculation revealed that the peak temperature of the molten pool significantly decreased and most of the volatile fission products were released from the molten pool during the accident. (authors)

  3. Occurrence and Spatial and Temporal Variations of Disinfection By-Products in the Water and Air of Two Indoor Swimming Pools

    Science.gov (United States)

    Catto, Cyril; Sabrina, Simard; Ginette, Charest-Tardif; Manuel, Rodriguez; Robert, Tardif

    2012-01-01

    In order to improve disinfection by-product (DBP) exposure assessment, this study was designed to document both water and air levels of these chemical contaminants in two indoor swimming pools and to analyze their within-day and day-to-day variations in both of them. Intensive sampling was carried out during two one-week campaigns to measure trihalomethanes (THMs) and chloramines (CAMs) in water and air, and haloacetic acids (HAAs) in water several times daily. Water samples were systematically collected at three locations in each pool and air samples were collected at various heights around the pool and in other rooms (e.g., changing room) in the buildings. In addition, the ability of various models to predict air concentrations from water was tested using this database. No clear trends, but actual variations of contamination levels, appeared for both water and air according to the sampling locations and times. Likewise, the available models resulted in realistic but imprecise estimates of air contamination levels from water. This study supports the recommendation that suitable minimal air and water sampling should be carried out in swimming pools to assess exposure to DBPs. PMID:23066383

  4. Analytical solution of nucleate pool boiling heat transfer model based on macrolayer

    Science.gov (United States)

    Danish, Mohd; Al Mesfer, Mohammed K.

    2018-02-01

    In the present work, a transient heat conduction model has been developed for heat transfer through macrolayer in nucleate regime of pool boiling. The developed heat transfer model was solved analytically (Laplace Transform) using appropriate initial and boundary conditions. The influence of macrolayer thickness, wall superheat, and time on conduction heat flux has been predicted. The average conduction heat flux as a function of wall superheat and macrolayer thickness has also been predicted. The findings of the study have been compared with experimental results, and they are in reasonable agreement. For higher values of wall superheat, which correspond to nucleate pool boiling, predicted results agree with experimental data. Findings also substantiate the assertion that heat conduction across the macrolayer constitutes the major mode of heat transfer from the heated wall to the boiling liquid in the macrolayer regime of pool boiling.

  5. Numerical Study of Condensation Heat Exchanger Design in a Subcooled Pool: Correlation Investigation

    International Nuclear Information System (INIS)

    Lee, Hee Joon; Ju, Yun Jae; Kang, Han Ok; Lee, Tae Ho; Park, Cheon Tae

    2012-01-01

    Generally the condensation heat exchanger has higher heat transfer coefficient compared to the single phase heat exchanger, so has been widely applied to the cooling systems of energy plant. Recently vertical or horizontal type condensation heat exchangers are being studied for the application to secondary passive cooling system of nuclear plants. Lee and Lee investigated the existing condensation correlation to the experiment for heat exchanger in saturated pool. They concluded Traviss' correlation showed most satisfactory results for the heat transfer coefficient and mass flow rate in a saturated water pool. In this study, a thermal sizing program of vertical condensation heat exchanger to design, TSCON(Thermal Sizing of CONdenser) was validated with the existing experimental data of condensation heat exchanger in a subcooled pool for pure steam condensation

  6. Swimming pool cleaner poisoning

    Science.gov (United States)

    ... outcome will depend on the extent of this damage. Opening a large bucket of chlorine tablets can expose you to a powerful chlorine gas that can be very poisonous. Always open the container outdoors. Keep your face as far away from ...

  7. New set of convective heat transfer coefficients established for pools and validated against CLARA experiments for application to corium pools

    International Nuclear Information System (INIS)

    Michel, B.

    2015-01-01

    Highlights: • A new set of 2D convective heat transfer correlations is proposed. • It takes into account different horizontal and lateral superficial velocities. • It is based on previously established correlations. • It is validated against recent CLARA experiments. • It has to be implemented in a 0D MCCI (molten core concrete interaction) code. - Abstract: During an hypothetical Pressurized Water Reactor (PWR) or Boiling Water Reactor (BWR) severe accident with core meltdown and vessel failure, corium would fall directly on the concrete reactor pit basemat if no water is present. The high temperature of the corium pool maintained by the residual power would lead to the erosion of the concrete walls and basemat of this reactor pit. The thermal decomposition of concrete will lead to the release of a significant amount of gases that will modify the corium pool thermal hydraulics. In particular, it will affect heat transfers between the corium pool and the concrete which determine the reactor pit ablation kinetics. A new set of convective heat transfer coefficients in a pool with different lateral and horizontal superficial gas velocities is modeled and validated against the recent CLARA experimental program. 155 tests of this program, in two size configurations and a high range of investigated viscosity, have been used to validate the model. Then, a method to define different lateral and horizontal superficial gas velocities in a 0D code is proposed together with a discussion about the possible viscosity in the reactor case when the pool is semi-solid. This model is going to be implemented in the 0D ASTEC/MEDICIS code in order to determine the impact of the convective heat transfer in the concrete ablation by corium

  8. Hydrodynamics and heat transfer characteristics of liquid pools with bubble agitation

    International Nuclear Information System (INIS)

    Blottner, F.G.

    1979-11-01

    Estimates are given for the heat transfer coefficients at various interfaces which occur in molten pools on concrete. Previous simulant experiments and correlations are used to determine the hydrodynamic behavior of the pool and heat transfer coefficients for the liquids of interest. Other studies assume a gas film occurs between the concrete and molten pool, but the results of this investigation do not confirm this assumption. The results also indicate the significant influence the very viscous concrete slag has on the properties of the molten pool. Additional experiments and analysis are needed to improve the accuracy of the heat transfer coefficients estimated and to understand the behavior of the concrete slag at the interface between the pool and decomposing concrete

  9. Heat transfer to sodium--potassium alloy in pool boiling

    International Nuclear Information System (INIS)

    Subbotin, V.I.; Sorokin, D.N.; Kudryavtsev, A.P.; Brigutsa, V.I.

    1974-01-01

    Results of an experimental investigation of superheating, heat transfer, and critical heat fluxes for the sodium-potassium alloy of the eutectic composition (78 wt percent K), as well as the dependence of the critical heat flux on the component concentration, are presented. (U.S.)

  10. Removals of cryptosporidium parvum oocysts and cryptosporidium-sized polystyrene microspheres from swimming pool water by diatomaceous earth filtration and perlite-sand filtration.

    Science.gov (United States)

    Lu, Ping; Amburgey, James E; Hill, Vincent R; Murphy, Jennifer L; Schneeberger, Chandra L; Arrowood, Michael J; Yuan, Tao

    2017-06-01

    Removal of Cryptosporidium-sized microspheres and Cryptosporidium parvum oocysts from swimming pools was investigated using diatomaceous earth (DE) precoat filtration and perlite-sand filtration. In pilot-scale experiments, microsphere removals of up to 2 log were obtained with 0.7 kg·DE/m 2 at a filtration rate of 5 m/h. A slightly higher microsphere removal (2.3 log) was obtained for these DE-precoated filters when the filtration rate was 3.6 m/h. Additionally, pilot-scale perlite-sand filters achieved greater than 2 log removal when at least 0.37 kg/m 2 of perlite was used compared to 0.1-0.4 log removal without perlite both at a surface loading rate of 37 m/h. Full-scale testing achieved 2.7 log of microspheres and oocysts removal when 0.7 kg·DE/m 2 was used at 3.6 m/h. Removals were significantly decreased by a 15-minute interruption of the flow (without any mechanical agitation) to the DE filter in pilot-scale studies, which was not observed in full-scale filters. Microsphere removals were 2.7 log by perlite-sand filtration in a full-scale swimming pool filter operated at 34 m/h with 0.5 kg/m 2 of perlite. The results demonstrate that either a DE precoat filter or a perlite-sand filter can improve the efficiency of removal of microspheres and oocysts from swimming pools over a standard sand filter under the conditions studied.

  11. Transient pool boiling heat transfer due to increasing heat inputs in subcooled water at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, K. [Kobe Univ. of Mercantile Marine (Japan); Shiotsu, M.; Sakurai, A. [Kyoto Univ. (Japan)

    1995-09-01

    Understanding of transient boiling phenomenon caused by increasing heat inputs in subcooled water at high pressures is necessary to predict correctly a severe accident due to a power burst in a water-cooled nuclear reactor. Transient maximum heat fluxes, q{sub max}, on a 1.2 mm diameter horizontal cylinder in a pool of saturated and subcooled water for exponential heat inputs, q{sub o}e{sup t/T}, with periods, {tau}, ranging from about 2 ms to 20 s at pressures from atmospheric up to 2063 kPa for water subcoolings from 0 to about 80 K were measured to obtain the extended data base to investigate the effect of high subcoolings on steady-state and transient maximum heat fluxes, q{sub max}. Two main mechanisms of q{sub max} exist depending on the exponential periods at low subcoolings. One is due to the time lag of the hydrodynamic instability which starts at steady-state maximum heat flux on fully developed nucleate boiling (FDNB), and the other is due to the heterogenous spontaneous nucleations (HSN) in flooded cavities which coexist with vapor bubbles growing up from active cavities. The shortest period corresponding to the maximum q{sub max} for long period range belonging to the former mechanism becomes longer and the q{sub max}mechanism for long period range shifts to that due the HSN on FDNB with the increase of subcooling and pressure. The longest period corresponding to the minimum q{sub max} for the short period range belonging to the latter mechanism becomes shorter with the increase in saturated pressure. On the contrary, the longest period becomes longer with the increase in subcooling at high pressures. Correlations for steady-state and transient maximum heat fluxes were presented for a wide range of pressure and subcooling.

  12. Numerical analysis of the heat and fluid flow in a weld pool with a dynamic keyhole

    International Nuclear Information System (INIS)

    Wu, C.S.; Zhang, T.; Feng, Y.H.

    2013-01-01

    Highlights: ► A model is developed to simulate the weld pool with a dynamic keyhole. ► The heat and fluid flow in such a moving plasma arc weld pool is analyzed. ► A combined volumetric heat source is established for such a model. ► The heat source height is adjusted by the keyhole depth at each time step. -- Abstract: In keyhole plasma arc welding, the interaction between the keyhole and the weld pool occurs when the keyhole appears inside the weld pool. The change of the keyhole shape and dimensions has direct effect on the heat and fluid flow in the weld pool, and the latter will also influence the keyhole geometry. In this study, the coupled behaviors of weld pool and keyhole are treated to develop a three-dimensional model for analyzing the heat and fluid flow inside a weld pool with a dynamic keyhole. In view of the characteristics of PAW process, a combined volumetric heat source model (double-ellipsoid plus conic body source) is established, and one of its distribution parameters is adjusted dynamically with the variation of the depth of keyhole. The physical phenomena, such as the weld pool development, the keyhole formation, the evolution of fluid flow and thermal field, the full-penetration of the test plates, and the transformation from a blind keyhole to an open keyhole, are quantitatively analyzed. The numerical results reveal the regularity of fluid flow in weld pool with a keyhole. The calculated keyhole shape and the fusion zone of plasma arc welds are compared with the experimental measurements. Both agree with each other generally. It lays foundation for optimizing the welding process parameters and improving the stability of plasma arc welding process

  13. Heat transfer in the decay pool of irradiated nuclear fuel

    International Nuclear Information System (INIS)

    Lorenzini, E.; Spiga, M.; Zerbini, D.

    1987-01-01

    Present work aims to analyze mono-dimensional, time dependent trends of the water temperature, assuming that there are no auxiliary cooling systems; this can simulate one of the worst hypothetical accidents which may occur in a nuclear plant. In fact the cooling of the spent fuel is provided only by natural convection; in this situation it is an interesting matter to valuate the time evolution of the water temperature and its maximum value. The accuracy of this method requires a very large computer time and makes it rather heavy and expensive. In this paper, a method to perform the mono-dimensional transient thermal hydraulic analysis of the storage pool is proposed. The pool is subdivided in horizontal isothermal segments; for every segment an enthalpy balance equation is deduced, taking account of a vertical mixing flow rate between adjacent segments, due to the convective fluid streams up and down

  14. Discussion on the Heat and Mass Transfer Model on the Pool Surface

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Soon-Joon; Choo, Yeon-Jun [FNC Tech., Yongin (Korea, Republic of); Ha, Sang-Jun [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Heat transfer on the pool surface involves the evaporation and condensation of steam in the presence of non-condensable gas. It is a kind of inter-phase heat transfer. This phenomenon has been regarded as less important on the thermal hydraulic behaviors such as pressure, temperature, hydrogen distribution, and so on in the nuclear reactor containment building. As a matter of fact, several RAIs (requests for additional information) during the licensing review of the developed CAP have been presented. And early in 2000s the steam condensation on the water surface of IRWST was a concern of APR1400 design. Such an increased concern is believed because it is a newly adopted system. This study discusses the pool surface heat transfer by reviewing the models of several well-known containment analysis codes, and conducting the sensitivities. This study discussed the pool surface heat transfer. The related models of CAP, GOTHIC, CONTEMPT-LT, and CONTEMPT4 were compared. The sensitivity of heat transfer coefficient for SKN3 and 4 using conventional code CONTEMPT-LT/028-A showed little effect. And the sensitivity of relative humidity and heat transfer area for latent heat transfer shows that CAP locates between GOTHIC and CONTEMPT4/MOD. The sensitivity for sensible heat transfer also shows similar trend. Conclusively, current CAP model of pool surface heat transfer has no fatal defect.

  15. Discussion on the Heat and Mass Transfer Model on the Pool Surface

    International Nuclear Information System (INIS)

    Hong, Soon-Joon; Choo, Yeon-Jun; Ha, Sang-Jun

    2016-01-01

    Heat transfer on the pool surface involves the evaporation and condensation of steam in the presence of non-condensable gas. It is a kind of inter-phase heat transfer. This phenomenon has been regarded as less important on the thermal hydraulic behaviors such as pressure, temperature, hydrogen distribution, and so on in the nuclear reactor containment building. As a matter of fact, several RAIs (requests for additional information) during the licensing review of the developed CAP have been presented. And early in 2000s the steam condensation on the water surface of IRWST was a concern of APR1400 design. Such an increased concern is believed because it is a newly adopted system. This study discusses the pool surface heat transfer by reviewing the models of several well-known containment analysis codes, and conducting the sensitivities. This study discussed the pool surface heat transfer. The related models of CAP, GOTHIC, CONTEMPT-LT, and CONTEMPT4 were compared. The sensitivity of heat transfer coefficient for SKN3 and 4 using conventional code CONTEMPT-LT/028-A showed little effect. And the sensitivity of relative humidity and heat transfer area for latent heat transfer shows that CAP locates between GOTHIC and CONTEMPT4/MOD. The sensitivity for sensible heat transfer also shows similar trend. Conclusively, current CAP model of pool surface heat transfer has no fatal defect

  16. Natural convection heat transfer characteristics of the molten metal pool with solidification by boiling coolant

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jae Seon; Suh, Kune Yull; Chung, Chang Hyun [Seoul National University, Seoul (Korea, Republic of); Paark, Rae Joon; Kim, Sang Baik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents results of experimental studies on the heat transfer and solidification of the molten metal pool with overlying coolant with boiling. The metal pool is heated from the bottom surface and coolant is injected onto the molten metal pool. Ad a result, the crust, which is a solidified layer, may form at the top of the molten metal pool. Heat transfer is accomplished by a conjugate mechanism, which consists of the natural convection of the molten metal pool, the conduction in the crust layer and the convective boiling heat transfer in the coolant. This work examines the crust formation and the heat transfer rate on the molten metal pool with boiling coolant. The simulant molten pool material is tin (Sn) with the melting temperature of 232 deg C. Demineralized water is used as the working coolant. The crust layer thickness was ostensibly varied by the heated bottom surface temperature of the test section, but not much affected by the coolant injection rate. The correlation between the Nusselt number and the Rayleigh number in the molten metal pool region of this study is compared against the crust formation experiment without coolant boiling and the literature correlations. The present experimental results are higher than those from the experiment without coolant boiling, but show general agreement with the Eckert correlation, with some deviations in the high and low ends of the Rayleigh number. This discrepancy is currently attributed to concurrent rapid boiling of the coolant on top of the metal layer. 10 refs., 4 figs., 1 tab. (Author)

  17. Pool boiling heat transfer to dilute copper oxide aqueous nano-fluids

    International Nuclear Information System (INIS)

    Sarafraz, M.M.; Hormozi, F.

    2015-01-01

    A set of experiments have been performed to quantify the pool boiling heat transfer coefficient of dilute copper oxide water-based nano-fluids at mass concentrations of 0.1-0.4%. To stabilize the two-step nano-fluids, pH control, stirring and sonication were utilized. For investigating the influence of surfactant as a surface active agent additive on the pool boiling heat transfer coefficient of nano-fluids, SDS, SDBS and Triton X-100 were used. Influence of some operating parameters such as applied heat flux, mass concentration of nano-fluids and other parameters such as roughness of surface, boiling contact angle and deposition on the pool boiling heat transfer coefficient of nano-fluids were experimentally investigated. Results demonstrated a significant deterioration of heat transfer coefficient of nano-fluids comparing with the base fluid in the absence of surfactants, however, in the presence of surfactant, higher pool boiling heat transfer coefficient was reported. According to results, roughness of surface is strongly controlled by nano-fluid concentration due to deposition of nano-fluids on the heating section. Rectilinear changes of deposition with time in term of fouling resistance were seen at both regions with natural convection and nucleate boiling dominant heat transfer mechanisms. (authors)

  18. Convective heat transfer correlations for molten core debris pools growing in concrete

    International Nuclear Information System (INIS)

    Felde, D.K.; Kim, H.S.; Abdel-Khalik, S.I.

    1980-01-01

    A volumetrically-heated pool with gas injection at the boundaries is used to simulate the heat transfer processes taking place in molten core debris-concrete systems. Measurements of the upward, downward, and sideward heat transfer rates at the pool boundaries have been made over wide ranges of power density, superficial gas velocity, and pool aspect ratio. Pools with either a free upper surface or an isothermal solid upper boundary to simulate an overlaying solid crust of oxides have been examined. Detailed measurements of the temperature distribution within the pool have also been made. A total of nearly 400 experiments, generalized correlations for the downward and sideward Nusselt numbers have been developed. The results indicate that the Nusselt numbers are nearly independent of the internal Rayleigh number and depend only on the nondimensional quantity (pV 3 /μg) where V is the superficial gas velocity, p is the pool density, μ is the viscosity, and g is the gravitational acceleration. The results also indicate that the downward and sideward Nusselt numbers in pools with gas release at the boundaries are comparable. This result is in contrast to the natural convection case where the sideward Nusselt numbers are significantly higher than those in the downward direction. The correlations developed in this investigation cover a wide range of the relevant nondimensional quantity (5 x 10 -10 3 /μg) -3 ). They can be used to determine the heat transfer rates at the pool boundaries, and hence, the pool growth rate into the concrete. Such information is necessary since it constitutes the last line of defence against violation of the containment. (orig.)

  19. The effect of coolant boiling on the molten metal pool heat transfer with local solidification

    International Nuclear Information System (INIS)

    Cho, Jae Seon; Suh, Kune Y.; Chung, Chang Hyun; Park, Rae joon; Kim, Sang Baik

    2000-01-01

    This study is concerned with the experimental test and numerical analysis of the heat transfer and solidification of the molten metal pool with overlying coolant with boiling. In the test, the metal pool is heated from the bottom surface and coolant is injected into the molten metal pool. Experiments were performed by changing the test section bottom surface temperature of the metal layer and the coolant injection rate. The two-phase boiling coolant experimental results are compared against the dry test without coolant or solidification of the molten metal pool, and against the crust formation experiment with subcooled coolant. Also, a numerical analysis is performed to check on the measured data. The numerical program is developed using the enthalpy method, the finite volume method and the SIMPLER algorithm. The experimental results of the heat transfer show general agreement with the calculated values. The present empirical test and numerical results of the heat transfer on the molten metal pool are apparently higher than those without coolant boiling. This is probably because this experiment was performed in concurrence of solidification in the molten metal pool and the rapid boiling of the coolant. The other experiments were performed without coolant boiling and the correlation was developed for the pure molten metal without phase change. (author)

  20. Heat transfer in pool boiling liquid neon, deuterium and hydrogen, and critical heat flux in forced convection of liquid neon

    International Nuclear Information System (INIS)

    Astruc, J.M.

    1967-12-01

    In the first part, free-convection and nucleate pool boiling heat transfer (up to burn-out heat flux) between a platinum wire of 0.15 mm in diameter in neon, deuterium and hydrogen has been studied at atmospheric pressure. These measurements were continued in liquid neon up to 23 bars (Pc ≅ 26.8 b). Film boiling heat transfer coefficients have been measured in pool boiling liquid neon at atmospheric pressure with three heating wires (diameters 0.2, 0.5, 2 mm). All the results have been compared with existing correlations. The second part is devoted to measurements of the critical heat flux limiting heat transfer with small temperature differences between the wall and the liquid neon flowing inside a tube (diameters 3 x 3.5 mm) heated by joule effect on 30 cm of length. Influences of flow stability, nature of electrical current, pressure, mass flow rate and subcooling are shown. In conclusion, the similarity of the heat transfer characteristics in pool boiling as well as in forced convection of liquid neon and hydrogen is emphasized. (author) [fr

  1. On heat transfer characteristics of real and simulant melt pool experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, T.N.; Nourgaliev R.R.; Sehgal, B.R. [Royal Institute of Technology, Stockholm (Sweden)

    1995-09-01

    The paper presents results of analytical studies of natural convection heat transfer in scaled and/or simulant melt pool experiments related to the PWR in-vessel melt retention issue. Specific reactor-scale effects of a large decay-heated core melt pool in the reactor pressure vessel lower plenum are first reviewed, and then the current analytical capability of describing physical processes under prototypical situations is examined. Experiments and experimental approaches are analysed by focusing on their ability to represent prototypical situations. Calculations are carried out in order to assess the significance of some selected effects, including variations in melt properties, pool geometry and heating conditions. Rayleigh numbers in the present analysis are limited to 10{sup 12}, where uncertainties in turbulence modeling are not overriding other uncertainties. The effects of fluid Prandtl number on heat transfer to the lowermost part of cooled pool walls are examined for square and semicircular cavities. Calculations are performed also to explore limitations of using side-wall heating and direct electrical heating in reproducing the physical picture of interest. Needs for further experimental and analytical efforts are discussed as well.

  2. The application of computational fluid dynamics and small-scale physical models to assess the effects of operational practices on the risk to public health within large indoor swimming pools.

    Science.gov (United States)

    Lewis, Lowell; Chew, John; Woodley, Iain; Colbourne, Jeni; Pond, Katherine

    2015-12-01

    Swimming pools provide an excellent facility for exercise and leisure but are also prone to contamination from microbial pathogens. The study modelled a 50-m × 20-m swimming pool using both a small-scale physical model and computational fluid dynamics to investigate how water and pathogens move around a pool in order to identify potential risk spots. Our study revealed a number of lessons for pool operators, designers and policy-makers: disinfection reaches the majority of a full-scale pool in approximately 16 minutes operating at the maximum permissible inlet velocity of 0.5 m/s. This suggests that where a pool is designed to have 15 paired inlets it is capable of distributing disinfectant throughout the water body within an acceptable time frame. However, the study also showed that the exchange rate of water is not uniform across the pool tank and that there is potential for areas of the pool tank to retain contaminated water for significant periods of time. 'Dead spots' exist at either end of the pool where pathogens could remain. This is particularly significant if there is a faecal release into the pool by bathers infected with Cryptosporidium parvum, increasing the potential for waterborne disease transmission.

  3. Pool boiling heat transfer on thin wire in nitrogen-tetrafluoromethane mixtures

    International Nuclear Information System (INIS)

    Amano, Toshiyuki.

    1993-01-01

    Nucleate and film pool boiling heat transfer, critical heat fluxes, and minimum heat fluxes for nitrogen, tetrafluoromethane, and their mixtures were measured on a thin wire. The orientation of the wire was either horizontal or vertical. Critical heat fluxes and minimum heat fluxes for the mixtures in any concentration were larger than those for liquid nitrogen. The heat flux in nucleate boiling regimes for mixtures was represented well by an experimental formula. For a single-component liquid, transition from nucleate boiling to film boiling was observed for a stepwise heat input and rapid heating. It was found that there was no such transition for mixtures in contrast to the pure component. The nitrogen-tetrafluoromethane mixtures are recommended for use as cryogens of oxide superconductors having critical temperature higher than 110 K

  4. Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters.

    Science.gov (United States)

    Cheema, Waqas A; Manasfi, Tarek; Kaarsholm, Kamilla M S; Andersen, Henrik R; Boudenne, Jean-Luc

    2017-12-01

    Several brominated disinfection by-products (DBPs) are formed in chlorinated seawater pools, due to the high concentration of bromide in seawater. UV irradiation is increasingly employed in freshwater pools, because UV treatment photodegrades harmful chloramines. However, in freshwater pools it has been reported that post-UV chlorination promotes the formation of other DBPs. To date, UV-based processes have not been investigated for DBPs in seawater pools. In this study, the effects of UV, followed by chlorination, on the concentration of three groups of DBPs were investigated in laboratory batch experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo-degradation, but the concentrations of trihalomethanes (THMs) and haloacetonitriles (HANs) increased with post-UV chlorination. Bromine incorporation in HAAs was significantly higher in the control samples chlorinated without UV irradiation but decreased significantly with UV treatment. Bromine incorporation was promoted in THM and HAN after UV and chlorine treatment. Overall, the accumulated bromine incorporation level in DBPs remained essentially unchanged in comparison with the control samples. Toxicity estimates increased with single-dose UV and chlorination, mainly due to increased HAN concentrations. However, brominated HANs are known in the literature to degrade following further UV treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Observation of contact area of bubbles with heating surface in pool boiling of water under microgravity

    International Nuclear Information System (INIS)

    Suzuki, K.; Kawamura, H.; Suzuki, M.; Takahashi, S.; Abe, Y.

    2003-01-01

    Burnout heat flux was measured in subcooled pool boiling of water under attached boiling bubbles on heating surface with bubble holding plate in ground experiment. A thin stainless flat plate was employed for heating surface. The experimental setup and the heating procedures were same as used in reduced gravity experiment performed by a parabolic flight of jet aircraft. Same burnout heat flux as in the reduced gravity was obtained by adjusting the clearance between the bubble holder and the heating surface. They were 100 ∝ 400 percent higher than the widely accepted existing theories. As extending heating time longer than the reduced gravity duration until burnout occurred, burnout heat flux decreased gradually and became a constant value calculated from the existing theories. In a result of observing contact area of boiling bubbles with transparent heating surface, the contact area was smaller in quick heating time than that in long time heating at same heat flux. The experimental results suggest in microgravity that liquid layer is remained between rapidly expanded bubbles and heating surface. In microgravity experiment by a drop shaft facility, contact area of bubbles with heating surface increased considerably at starting of microgravity. (orig.)

  6. Effect of medium-pressure UV-lamp treatment on disinfection by-products in chlorinated seawater swimming pool waters

    DEFF Research Database (Denmark)

    Cheema, Waqas Akram; Manasfi, Tarek; Kaarsholm, Kamilla Marie Speht

    2017-01-01

    experiments using a medium-pressure UV lamp. Chlorine consumption increased following post-UV chlorination, most likely because UV irradiation degraded organic matter in the pool samples to more chlorine-reactive organic matter. Haloacetic acid (HAA) concentrations decreased significantly, due to photo...

  7. Surface renewal model for heat transfer calculation between a porous solid wall and an internally heated bubbling pool

    International Nuclear Information System (INIS)

    Tourniaire, B.

    2005-01-01

    Full text of publication follows: This work has been performed in the frame of the study of severe accident of LWR involving core meltdown and failure of the reactor vessel with molten corium relocation in the reactor pit. One of the main issue in nuclear safety is the estimation of the time when the reactor cavity may fail due to the erosion of the basemat since it would lead to the contamination of the groundwater. The calculation of the basemat erosion velocity requires the knowledge of the heat transfer between the corium pool and the concrete. Due to the gas release (mainly CO 2 and H 2 O) resulting from the concrete erosion, two-phase flow heat transfers occur during molten core concrete interaction (MCCI). Two-phase flow heat transfer between a porous horizontal wall and an internally heated bubbling pool has been already extensively investigated on the experimental side by several authors (Kutateladze and Malenkov, Duignan et al, Bonnet et al, Bilbao y Leon et al). The effect of various parameters such as the physical properties of the fluid or the pool aspect ratio has been studied so that many experimental data are available. From dimensional analysis (Kutateladze-Malenkov, Bonnet et al) or theoretical approach (Konsetov) and from these experimental data, heat transfer correlations have been proposed based on usual non-dimensional groups as Nu, Pr, Ra, etc. Today, the most widely used correlation in MCCI study are those proposed by Konsetov and by Kutateladze and Malenkov. Comparisons of the results of these correlations with available experimental data show that not all tendencies are well reproduced. The main purpose of this paper is to present an alternative heat transfer correlation that can be used in MCCI study. This correlation has been proposed by Deckwer in the frame of the study of heat transfer in bubble column reactors dedicated to chemical engineering. This correlation has been deduced from a theoretical analysis based on a surface renewal

  8. Trihalometanos en el agua de piscinas en cuatro zonas de España participantes en el proyecto INMA Trihalomethanes in swimming pool water in four areas of Spain participating in the INMA project

    Directory of Open Access Journals (Sweden)

    Laia Font-Ribera

    2010-12-01

    Full Text Available Objetivo: La natación es uno de los deportes más practicados en España, por personas de todas las edades y condiciones físicas. También es una vía de exposición a subproductos de la desinfección, compuestos potencialmente tóxicos. Su concentración en el agua de las piscinas no está legislada y es poco conocida. El objetivo de este trabajo es describir la concentración de trihalometanos en el agua de piscinas de los municipios de cuatro cohortes del estudio INMA. Métodos: En julio de 2009 se analizaron los trihalometanos en el agua de piscinas (n=27 de Asturias, Granada, Valencia y Sabadell. Resultados: La concentración media de trihalometanos totales fue de 42,7µg/l (desviación estándar [DE]=19,1 en las piscinas interiores y de 151,2µg/l (DE=80,7 en las exteriores, predominando siempre el cloroformo. Granada tuvo los valores más bajos. Conclusión: La concentración de trihalometanos en el agua de piscinas presenta una gran variabilidad. Las piscinas exteriores tienen valores más altos, superando mayoritariamente los límites legales establecidos para el agua de consumo.Objective: Swimming is one of the most widely practiced sports in Spain among people of all ages and physical conditions. This activity is also a source of exposure to disinfection by-products (DBP, which are potentially toxic. The DBP concentration in swimming pool water is not regulated and is poorly known. The aim of this study was to describe trihalomethane concentrations in swimming pool water in the municipalities of four cohorts of the INMA project. Methods: In July 2009, trihalomethanes were analyzed in water from 27 swimming pools in Asturias, Granada, Valencia and Sabadell. Results: The mean total trihalomethane concentration was 42.7µg/L (standard deviation [SD]=19.1 in indoor pools and 151.2µg/L (SD=80.7 in outdoor pools. In all pools, the most abundant trihalomethane was always chloroform. The lowest levels were found in Granada. Conclusion

  9. SWISS: Sustained heated metallic melt/concrete interactions with overlying water pools

    International Nuclear Information System (INIS)

    Blose, R.E.; Gronager, J.E.; Suo-Anttila, A.J.; Brockmann, J.E.

    1987-07-01

    Results of the test SWISS-1 and test SWISS-2 are reported. These tests examined the effects of an overlying water pool on high temperature melt interactions with concrete. In both tests, a melt of about 46 kilograms of type 304 stainless steel was formed and deposited onto a 21.6 cm diameter disk of limestone/common sand concrete. The concrete disk was retained within a cast MgO annulus. The molten steel was sustained at a power input of 1.3 to 1.7 Watts/gram by induction heating. In test SWISS-1 a water pool was formed over the melt after about 12 cm of concrete had eroded. In test SWISS-2, the water pool was formed about one minute after melt contacted the concrete and before any significant erosion of concrete could take place. In both tests the water pool was kept below the boiling point. Interactions were sustained for about 40 minutes in the two tests. Concrete erosion rates, concrete temperatures, heat fluxes to the overlying water pool, gas generation rates, and evolved gas compositions during tests SWISS-1 and SWISS-2 are reported. Aerosol generation rates are reported for test SWISS-2. 46 refs., 70 figs., 26 tabs

  10. Sensitivity Analysis of Depletion Parameters for Heat Load Evaluation of PWR Spent Fuel Storage Pool

    International Nuclear Information System (INIS)

    Kim, In Young; Lee, Un Chul

    2011-01-01

    As necessity of safety re-evaluation for spent fuel storage facility has emphasized after the Fukushima accident, accuracy improvement of heat load evaluation has become more important to acquire reliable thermal-hydraulic evaluation results. As groundwork, parametric and sensitivity analyses of various storage conditions for Kori Unit 4 spent fuel storage pool and spent fuel depletion parameters such as axial burnup effect, operation history, and specific heat are conducted using ORIGEN2 code. According to heat load evaluation and parametric sensitivity analyses, decay heat of last discharged fuel comprises maximum 80.42% of total heat load of storage facility and there is a negative correlation between effect of depletion parameters and cooling period. It is determined that specific heat is most influential parameter and operation history is secondly influential parameter. And decay heat of just discharged fuel is varied from 0.34 to 1.66 times of average value and decay heat of 1 year cooled fuel is varied from 0.55 to 1.37 times of average value in accordance with change of specific power. Namely depletion parameters can cause large variation in decay heat calculation of short-term cooled fuel. Therefore application of real operation data instead of user selection value is needed to improve evaluation accuracy. It is expected that these results could be used to improve accuracy of heat load assessment and evaluate uncertainty of calculated heat load.

  11. Development of surface wettability characteristics for enhancing pool boiling heat transfer

    International Nuclear Information System (INIS)

    Kim, Moo Hwan; Jo, Hang Jin

    2010-05-01

    For several centuries, many boiling experiments have been conducted. Based on literature survey, the characteristic of heating surface in boiling condition played as an important role which mainly influenced to boiling performance. Among many surface factor, the fact that wettability effect is significant to not only the enhancement of critical heat flux(CHF) but also the nucleate boiling heat transfer is also supported by other kinds of boiling experiments. In this regard, the excellent boiling performance (a high CHF and heat transfer performance) in pool boiling could be achieved through some favorable surface modification which satisfies the optimized wettability condition. To find the optimized boiling condition, we design the special heaters to examine how two materials, which have different wettability (e.g. hydrophilic and hydrophobic), affect the boiling phenomena. The special heaters have hydrophobic dots on hydrophilic surface. The contact angle of hydrophobic surface is 120 .deg. to water at the room temperature. The contact angle of hydrophilic surface is 60 .deg. at same conditions. To conduct the experiment with new surface condition, we developed new fabrication method and design the pool boiling experimental apparatus. Through this facility, we can the higher CHF on pattern surface than that on hydrophobic surface, and the higher boiling heat transfer performance on pattern surface than that on hydrophilic surface. Based on this experimental results, we concluded that we proposed new heating surface condition and surface fabrication method to realize the best boiling condition by modified heating surface condition

  12. Frequency and Genotyping of Acanthamoeba Species in the Swimming Pools and Ponds of Khoramabad, Iran, in 2016

    Directory of Open Access Journals (Sweden)

    M. Faraji

    2017-10-01

    Full Text Available Background and Objective: Acanthamoeba is a free-living and opportunistic amoeba found in the water, soil, and air. This amoeba causes granulomatous amoebic encephalitis in the immunocompromised patients and amoebic keratitis in the people using contact lenses. The genotypes of Acanthamoeba are pathogenic and non-pathogenic. Regarding this, the present study aimed to determine the frequency and genotypes of Acanthamoeba in the water pools and ponds of Khorramabad, Iran, using culture, polymerase chain reaction (PCR, and sequencing methods in 2016. Materials and Methods: This study was conducted on a total of 84 water samples collected from the water pools and ponds of Khorramabad. The samples were filtered using nitrocellulose syringe (0.45 μm; subsequently, they were cultured on 1.5% non-nutrient agar, covered by killed Escherichia coli and incubated at 27ºC. After the extraction of DNA from positive samples, PCR was performed using specific primers to detect and confirm Acanthamoeba. Then, for genotyping, the PCR products of positive samples were sequenced. Results: Out of the 84 water samples, 50 (59.5% cases were positive for amoeba in the culture method. However, the results of the PCR revealed 35 (41.7% positive samples for Acanthamoeba. The sequencing of the PCR products demonstrated that 17 samples were T4 genotype (pathogen, and the rest were other Acanthamoeba genotypes. Conclusion: This study indicated the high prevalence of Acanthamoeba species, especially the pathogenic type, in the water pools of Khoramabad that could be a source of infection risk for humans. Regarding the fact that almost half of the found genotypes were pathogenic (genotype T4 that are the main cause of amoebic keratitis, these water bodies could be a potential risk factor for the public health. Therefore, the health professionals should prevent contamination.

  13. Validation of effective momentum and heat flux models for stratification and mixing in a water pool

    Energy Technology Data Exchange (ETDEWEB)

    Hua Li; Villanueva, W.; Kudinov, P. [Royal Institute of Technology (KTH), Div. of Nuclear Power Safety, Stockholm (Sweden)

    2013-06-15

    The pressure suppression pool is the most important feature of the pressure suppression system in a Boiling Water Reactor (BWR) that acts primarily as a passive heat sink during a loss of coolant accident (LOCA) or when the reactor is isolated from the main heat sink. The steam injection into the pool through the blowdown pipes can lead to short term dynamic phenomena and long term thermal transient in the pool. The development of thermal stratification or mixing in the pool is a transient phenomenon that can influence the pool's pressure suppression capacity. Different condensation regimes depending on the pool's bulk temperature and steam flow rates determine the onset of thermal stratification or erosion of stratified layers. Previously, we have proposed to model the effect of steam injection on the mixing and stratification with the Effective Heat Source (EHS) and the Effective Momentum Source (EMS) models. The EHS model is used to provide thermal effect of steam injection on the pool, preserving heat and mass balance. The EMS model is used to simulate momentum induced by steam injection in different flow regimes. The EMS model is based on the combination of (i) synthetic jet theory, which predicts effective momentum if amplitude and frequency of flow oscillations in the pipe are given, and (ii) model proposed by Aya and Nariai for prediction of the amplitude and frequency of oscillations at a given pool temperature and steam mass flux. The complete EHS/EMS models only require the steam mass flux, initial pool bulk temperature, and design-specific parameters, to predict thermal stratification and mixing in a pressure suppression pool. In this work we use EHS/EMS models implemented in containment thermal hydraulic code GOTHIC. The PPOOLEX experiments (Lappeenranta University of Technology, Finland) are utilized to (a) quantify errors due to GOTHIC's physical models and numerical schemes, (b) propose necessary improvements in GOTHIC sub-grid scale

  14. Improved prediction of critical heat flux in liquid metal pool boiling

    International Nuclear Information System (INIS)

    Bankoff, S.G.; Fauske, H.K.

    1974-01-01

    The Kutateladze criterion for the pool boiling critical heat flux, which works well for nonmetallic liquids at or above atmospheric pressure, fails for the alkali liquid metals in the pressure range of interest for Liquid Metal Fast Breeder Reactor applications. In this pressure range bubble growth of the alkali liquid metals is largely inertia-controlled, in view of the large thermal conductivities, which implies a significant condensing heat flux within the bubbles themselves. The bubble growth is assumed to be described by the Mikic, Rohsenow, and Griffith equation. In this way a mean bubble age is determined, and hence a mean bubble thermal boundary layer thickness. The time-average critical heat flux is then obtained as the sum of the Kutateladze flux and the flux due to condensation on the bubble surfaces. No empirical parameters are employed. The present analysis predicts critical heat fluxes lying generally within the data band. (U.S.)

  15. Transition process leading to microbubble emission boiling on horizontal circular heated surface in subcooled pool

    Science.gov (United States)

    Ueno, Ichiro; Ando, Jun; Horiuchi, Kazuna; Saiki, Takahito; Kaneko, Toshihiro

    2016-11-01

    Microbubble emission boiling (MEB) produces a higher heat flux than critical heat flux (CHF) and therefore has been investigated in terms of its heat transfer characteristics as well as the conditions under which MEB occurs. Its physical mechanism, however, is not yet clearly understood. We carried out a series of experiments to examine boiling on horizontal circular heated surfaces of 5 mm and of 10 mm in diameter, in a subcooled pool, paying close attention to the transition process to MEB. High-speed observation results show that, in the MEB regime, the growth, condensation, and collapse of the vapor bubbles occur within a very short time. In addition, a number of fine bubbles are emitted from the collapse of the vapor bubbles. By tracking these tiny bubbles, we clearly visualize that the collapse of the vapor bubbles drives the liquid near the bubbles towards the heated surface, such that the convection field around the vapor bubbles under MEB significantly differs from that under nucleate boiling. Moreover, the axial temperature gradient in a heated block (quasi-heat flux) indicates a clear difference between nucleate boiling and MEB. A combination of quasi-heat flux and the measurement of the behavior of the vapor bubbles allows us to discuss the transition to MEB. This work was financially supported by the 45th Research Grant in Natural Sciences from The Mitsubishi Foundation (2014 - 2015), and by Research Grant for Boiler and Pressurized Vessels from The Japan Boiler Association (2016).

  16. Experimental study of nucleate pool boiling heat transfer of water on silicon oxide nanoparticle coated copper heating surface

    International Nuclear Information System (INIS)

    Das, Sudev; Kumar, D.S.; Bhaumik, Swapan

    2016-01-01

    Highlights: • EBPVD approach was employed for fabrication of well-ordered nanoparticle coated micro/nanostructure on metal surface. • Nucleate boiling heat transfer performance on nanoparticle coated micro/nanostructure surface was experimentally studied. • Stability of nanoparticle coated surface under boiling environment was systematically studied. • 58% enhancement of boiling heat transfer coefficient was found. • Present experimental results are validated with well known boiling correlations. - Abstract: Electron beam physical vapor deposition (EBPVD) coating approach was employed for fabrication of well-ordered of nanoparticle coated micronanostructures on metal surfaces. This paper reports the experimental study of augmentation of pool boiling heat transfer performance and stabilities of silicon oxide nanoparticle coated surfaces with water at atmospheric pressure. The surfaces were characterized with respect to dynamic contact angle, surface roughness, topography, and morphology. The results were found that there is a reduction of about 36% in the incipience superheat and 58% enhancement in heat transfer coefficient for silicon oxide coated surface over the untreated surface. This enhancement might be the reason of enhanced wettability, enhanced surface roughness and increased number of a small artificial cavity on a heating surface. The performance and stability of nanoparticle coated micro/nanostructure surfaces were examined and found that after three runs of experiment the heat transfer coefficient with heat flux almost remain constant.

  17. Evaluation of Total Coliform, Fecal Coliform and Residual Chlorine in Swimming Pools in Kermanshah on the Season, the type of Pool, Disinfection System and Source of Water Supply in the during of three years (2010-2012

    Directory of Open Access Journals (Sweden)

    K SHarafi

    2014-11-01

    From the results , although the pools of water quality parameters has been studied in almost ideal But in summer, especially on a female pools and pools with wells water supply source than other pools , to be more oversight .

  18. Interfacial energies of aqueous mixtures and porous coverings for enhancing pool boiling heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Melendez, Elva [CIICAp, Universidad Autonoma del Estado de Morelos, 62210 (Mexico); Reyes, Rene [Departamento de Ingenieria Quimica y Alimentos, Universidad de las Americas Puebla, Santa Catarina Martir Cholula, Puebla 72820 (Mexico)

    2006-08-15

    The interfacial energies effects on pool boiling were measured for combinations of aqueous ethanol mixtures and cationic surfactants. The mixture with 16% ethanol by weight had the lowest contact angle (associated to the highest wettability) and produced the highest convective heat transfer coefficient, h, among the aqueous ethanol mixtures. The surfactant sodium-lauryl-sulfate added at 100 ppm (its calculated critical micelle concentration CMC) to the 16% ethanol aqueous mixture produced an additional increment of the wettability of the mixture and of the h values; other concentrations of the surfactant reduced de contact angle and h values. The effect of these interfacial energies represents a mass-transfer contribution to pool boiling and the proposal of mixture effects both as increased spreadability and as micelle states. Several randomly constructed porous coverings, contributing to the breakage of vapor slugs around the heater, were tested; produced the highest h values for average pore diameters of 0.5 mm, and covering thickness of 0.972 mm. The synergistic effect on h of the interfacial energies of mixtures at their critical micelle concentration, and porous coverings was measured. Therefore, the independent driving forces combined in this study for increasing pool boiling heat transfer are (a) spreadability of the liquid on the solid; (b) the bubble's size reduction, achieved by micelle states; and (c) the bubble's breakage, induced by the porous coverings, for vapor flow not under pressure drop control. (author)

  19. Growth of a bubble at a heated surface in a pool of liquid metal

    International Nuclear Information System (INIS)

    Bankoff, S.G.; Choi, H.K.

    1976-01-01

    A theoretical investigation of the initial vapor bubble growth from a heated wall in a pool of liquid is reported. The analysis assumes the bubble to have the shape of a spherical sector, at the base of which a thin liquid microlayer is retained on the heating surface. The effects of time-and-space dependent heat conduction in the solid, microlayer vaporization, and non-equilibrium condensation on the bubble upper surface are considered. A two-term expression for the bubble growth rate is obtained by a collocation procedure. Calculated results predict the growth of the bubble on a heated surface as a function of the heat flux, the external pressure and the thermophysical properties of the liquid and solid. An expression due to Ruckenstein, modified to take into account the effective contact angle, is used to determine the departure bubble diameter. This turns out to be sensitive to the contact angle, and less strongly influenced by the bubble drag coefficient. The growth is initially inertia-controlled, but heat-transfer effects become significant before departure. In this pressure range (0.1 to 1 atm) the presence of inert gas, by reducing the effective accommodation coefficient for condensation, increases bubble growth rate moderately. (author)

  20. Heat transfer in nucleate pool boiling of aqueous SDS and triton X-100 solutions

    Energy Technology Data Exchange (ETDEWEB)

    Wasekar, Vivek M. [Tata Steel Limited, Department of Research and Development, Jamshedpur (India)

    2009-09-15

    Variation in degree of surface wettability is presented through the application of Cooper's correlative approach (h{proportional_to}M{sup -0.5}q{sub w}''0.67) for computing enhancement ({phi}) in nucleate pool boiling of aqueous solutions of SDS and Triton X-100 and its presentation with Marangoni parameter ({chi}) that represents the dynamic convection effects due to surface tension gradients. Dynamic spreading coefficient defined as {sigma} {sub dyn}N{sub a}, which relates spreading and wetting characteristics with the active nucleation site density on the heated surface and bubble evolution process, represents cavity filling and activation process and eliminates the concentration dependence of nucleate pool boiling heat transfer in boiling of aqueous surfactant solutions. Using the dynamic spreading coefficient ({sigma}{sub dyn}N{sub a}=0.09q{sub w}''0.71), correlation predictions within {+-}15% for both SDS and triton X-100 solutions for low heat flux boiling condition (q{sub w}''{<=} 100 kW/m {sup 2}) characterised primarily by isolated bubble regime are presented. (orig.)

  1. Pool-Boiling Heat-Transfer Enhancement on Cylindrical Surfaces with Hybrid Wettable Patterns.

    Science.gov (United States)

    Kumar C S, Sujith; Chang, Yao Wen; Chen, Ping-Hei

    2017-04-10

    In this study, pool-boiling heat-transfer experiments were performed to investigate the effect of the number of interlines and the orientation of the hybrid wettable pattern. Hybrid wettable patterns were produced by coating superhydrophilic SiO2 on a masked, hydrophobic, cylindrical copper surface. Using de-ionized (DI) water as the working fluid, pool-boiling heat-transfer studies were conducted on the different surface-treated copper cylinders of a 25-mm diameter and a 40-mm length. The experimental results showed that the number of interlines and the orientation of the hybrid wettable pattern influenced the wall superheat and the HTC. By increasing the number of interlines, the HTC was enhanced when compared to the plain surface. Images obtained from the charge-coupled device (CCD) camera indicated that more bubbles formed on the interlines as compared to other parts. The hybrid wettable pattern with the lowermost section being hydrophobic gave the best heat-transfer coefficient (HTC). The experimental results indicated that the bubble dynamics of the surface is an important factor that determines the nucleate boiling.

  2. Solar systems and heat pumps in operation in Carinthia: results 1994 - 1997

    International Nuclear Information System (INIS)

    Faninger, G.

    1998-04-01

    Solar systems and heat pumps in operation in Carinthia: results 1994 - 1997. Test results from solar systems for swimming pool heating, hot water preparation and space heating as well as heat pumps for hot water preparation, space heating and heat recovery will be reported and assessed collectively. (author)

  3. Study of Nuclear Decay Data Contribution to Uncertainties in Heat Load Estimations for Spent Fuel Pools

    Science.gov (United States)

    Ferroukhi, H.; Leray, O.; Hursin, M.; Vasiliev, A.; Perret, G.; Pautz, A.

    2014-04-01

    At the Paul Scherrer Institut (PSI), a methodology for nuclear data uncertainty propagation in CASMO-5M (C5M) assembly calculations is under development. This paper presents a preliminary application of this methodology to C5M decay heat calculations. Applying a stochastic sampling method, nuclear decay data uncertainties are first propagated for the cooling phase only. Thereafter, the uncertainty propagation is enlarged to gradually account for cross-section as well as fission yield uncertainties during the depletion phase. On that basis, assembly heat load uncertainties as well as total uncertainty for the entire pool are quantified for cooling times up to one year. The relative contributions from the various types of nuclear data uncertainties are in this context also estimated.

  4. Parametric investigation on transient boiling heat transfer of metal rod cooled rapidly in water pool

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chi Young [Department of Fire Protection Engineering, Pukyong National University, 45, Yongso-ro, Nam-gu, Busan 48513 (Korea, Republic of); Kim, Sunwoo, E-mail: swkim@alaska.edu [Mechanical Engineering Department, University of Alaska Fairbanks, P. O. Box 755905, Fairbanks, AK 99775-5905 (United States)

    2017-03-15

    Highlights: • Effects of liquid subcooling, surface coating, material property, and surface oxidation are examined. • Liquid subcooling affects remarkably the quenching phenomena. • Cr-coated surfaces for ATF might extend the quenching duration. • Solids with low heat capacity shorten the quenching duration. • Surface oxidation can affect strongly the film boiling heat transfer and MFB point. - Abstract: In this work, the effects of liquid subcooling, surface coating, material property, and surface oxidation on transient pool boiling heat transfer were investigated experimentally using the vertical metal rod and quenching method. The change in rod temperature was measured with time during quenching, and the visualization of boiling around the test specimen was performed using the high-speed video camera. As the test materials, the zircaloy (Zry), stainless steel (SS), niobium (Nb), and copper (Cu) were tested. In addition, the chromium-coated niobium (Cr-Nb) and chromium-coated stainless steel (Cr-SS) were prepared for accident tolerant fuel (ATF) application. Low liquid subcooling and Cr-coating shifted the quenching curve to the right, which indicates a prolongation of quenching duration. On the other hand, the material with small heat capacity and surface oxidation caused the quenching curve to move to the left. To examine the influence of the material property and surface oxidation on the film boiling heat transfer performance and minimum film boiling (MFB) point in more detail, the wall temperature and heat flux were calculated from the present transient temperature profile using the inverse heat transfer analysis, and then the curves of wall temperature and heat flux in the film boiling regime were obtained. In the present experimental conditions, the effect of material property on the film boiling heat transfer performance and MFB point seemed to be minor. On the other hand, based on the experimental results of the Cu test specimen, the surface

  5. Bubble Departure from Metal-Graphite Composite Surfaces and Its Effects on Pool Boiling Heat Transfer

    Science.gov (United States)

    Chao, David F.; Sankovic, John M.; Motil, Brian J.; Yang, W-J.; Zhang, Nengli

    2010-01-01

    The formation and growth processes of a bubble in the vicinity of graphite micro-fiber tips on metal-graphite composite boiling surfaces and their effects on boiling behavior are investigated. It is discovered that a large number of micro bubbles are formed first at the micro scratches and cavities on the metal matrix in pool boiling. By virtue of the non-wetting property of graphite, once the growing micro bubbles touch the graphite tips, the micro bubbles are sucked by the tips and merged into larger micro bubbles sitting on the end of the tips. The micro bubbles grow rapidly and coalesce to form macro bubbles, each spanning several tips. The necking process of a detaching macro bubble is analyzed. It is revealed that a liquid jet is produced by sudden break-off of the bubble throat. The composite surfaces not only have higher temperatures in micro- and macrolayers but also make higher frequency of the bubble departure, which increase the average heat fluxes in both the bubble growth stage and in the bubble departure period. Based on these analyses, the enhancement mechanism of pool boiling heat transfer on composite surfaces is clearly revealed.

  6. Independent and collective roles of surface structures at different length scales on pool boiling heat transfer

    Science.gov (United States)

    Li, Calvin H.; Rioux, Russell P.

    2016-01-01

    Spherical Cu nanocavity surfaces are synthesized to examine the individual role of contact angles in connecting lateral Rayleigh-Taylor wavelength to vertical Kevin-Helmholtz wavelength on hydrodynamic instability for the onset of pool boiling Critical Heat Flux (CHF). Solid and porous Cu pillar surfaces are sintered to investigate the individual role of pillar structure pitch at millimeter scale, named as module wavelength, on hydrodynamic instability at CHF. Last, spherical Cu nanocavities are coated on the porous Cu pillars to create a multiscale Cu structure, which is studied to examine the collective role and relative significance of contact angles and module wavelength on hydrodynamic instability at CHF, and the results indicate that module wavelength plays the dominant role on hydrodynamic instability at CHF when the height of surface structures is equal or above ¼ Kelvin-Helmholtz wavelength. Pool boiling Heat Transfer Coefficient (HTC) enhancements on spherical Cu nanocavity surfaces, solid and porous Cu pillar surfaces, and the integrated multiscale structure have been investigated, too. The experimental results reveal that the nanostructures and porous pillar structures can be combined together to achieve even higher enhancement of HTC than that of individual structures. PMID:27841322

  7. Bakteri Legionella pneumophila Terdeteksi pada Air Kolam Renang di Kota Surabaya dengan Nested Polymerase Chain Reaction (LEGIONELLA PNEUMOPHILA BACTERIADETECTED IN SWIMMING POOL WATER OF SURABAYA BY USING NESTED POLYMERASE CHAIN REACTION

    Directory of Open Access Journals (Sweden)

    Eduardus Bimo Aksono

    2017-06-01

    Full Text Available Legionella pneumophila is a Gram-negative bacillus that causes nosocomial and community-acquired pneumonia. The aim of this research was to detect the presence of bacteria of L. pneumophila species in the swimming pools water of Surabaya city by using nested Polymerase Chain Reaction (PCR assay of a specific gene for L. pneumophila (mip gene. This study used purposive sampling method. A total of 10 water samples were collected from five swimming pools consisting of 200 mL water for each swimming pool. The results showed that of 10 samples tested by nested PCR, one sample was positive for L. pneumophila, and nine samples were negative. L. pneumophila were found in pool water samples with a higher temperature (>30ºC.Serogrouping analysis of positive sample that L. pneumophila bacteria detected in the water sample of swimming pool in Surabaya was L. pneumophila serogroup 9 (98% and serogroup 10 (98%. L. pneumophila detection of bacteria is expected to raise the awareness of physician and microbiologists about the transmission of L. pneumophila and will also be useful for controlling the agents. ABSTRAK Legionella pneumophila adalah bakteri Gram-negatif berbentuk batang yang dapat menyebabkan penyakit nosokomial dan pneumonia. Tujuan penelitian ini adalah untuk mendeteksi keberadaan bakteri L. pneumophila pada air kolam renang di Kota Surabaya dengan menggunakan nested Polymerase Chain Reaction (PCR berbasis gen spesifik L. pneumophila (mip gene. Penelitian ini menggunakan metode purposive sampling. Sebanyak sepuluh sampel diambil dari lima kolam renang. Sampel diambil sebanyak 200 mL dari air kolam renang di setiap lokasi. Hasil dari 10 sampel yang diuji menggunakan nested PCR, satu sampel menunjukkan hasil positif untuk L.pneumophila, dan sembilan sampel menunjukkan hasil negatif. Bakteri L. pneumophila ditemukan pada sampel air kolam dengan suhu yang lebih tinggi (>30ºC. Satu sampel positip tersebut ketika dilanjutkan terhadap analisis serogrup

  8. The dynamic warm pool: A new paradigm for understanding the role of the tropics in the global heat balance

    Science.gov (United States)

    Webster, P. J.; Hoyos, C. D.

    2008-12-01

    The region of atmospheric heating in the tropics, here termed the dynamic warm pool, represents the "boiler box" of the planetary heat engine and plays a determining role in global climate and tropical weather variability, modulating the genesis and intensification of tropical cyclones, the ascending branches of the Walker and Hadley circulations, monsoons and ENSO variability, and the nature of global teleconnections emanating from the tropics. Hence, it is important to understand how the tropical warm pool has changed in the past and how it may change in the future, and how these changes may alter climate both regionally and globally. The concept of the dynamic warm pool, which encloses the region of net atmospheric convective heating in the tropics, is fundamentally different to the traditionally defined oceanic warm pool corresponding to the area occupied by sea surface temperatures above a pre-defined threshold, typically 28C. While the traditionally defined warm pool has expanded as a result of global warming, the dynamical warm pool has remained constant as a result of an increasing column integrated heating-sea surface temperature threshold. In other words, in a warming climate the convective area does not expand with the area of SST>28C. However, despite the near constancy of the dynamic warm pool area, the magnitude of the column integrated heating in the tropics increases substantially. In light of these results, the traditional warm pool definition and the thresholds for convection and cyclogenesis are not climatically meaningful and lack a physical basis. Rather than a static definition set by a constant temperature, the climatically active warm pool should be defined dynamically by the large-scale coupled ocean-atmosphere system rather than just by the temperature of the ocean surface. In this work we use the concept of the dynamical warm pool as a physical basis to explore and understand long-term variability of tropical cyclogenesis and

  9. Enhancement of Pool Boiling Heat Transfer in Water Using Sintered Copper Microporous Coatings

    Directory of Open Access Journals (Sweden)

    Seongchul Jun

    2016-08-01

    Full Text Available Pool boiling heat transfer of water saturated at atmospheric pressure was investigated experimentally on Cu surfaces with high-temperature, thermally-conductive, microporous coatings (HTCMC. The coatings were created by sintering Cu powders on Cu surfaces in a nitrogen gas environment. A parametric study of the effects of particle size and coating thickness was conducted using three average particle sizes (APSs of 10 μm, 25 μm, and 67 μm and various coating thicknesses. It was found that nucleate boiling heat transfer (NBHT and critical heat flux (CHF were enhanced significantly for sintered microporous coatings. This is believed to have resulted from the random porous structures that appear to include reentrant type cavities. The maximum NBHT coefficient was measured to be approximately 400 kW/m2k with APS 67 μm and 296 μm coating thicknesses. This value is approximately eight times higher than that of a plain Cu surface. The maximum CHF observed was 2.1 MW/m2 at APS 67 μm and 428 μm coating thicknesses, which is approximately double the CHF of a plain Cu surface. The enhancement of NBHT and CHF appeared to increase as the particle size increased in the tested range. However, two larger particle sizes (25 μm and 67 μm showed a similar level of enhancement.

  10. Non-electric applications of pool-type nuclear reactors

    International Nuclear Information System (INIS)

    Adamov, E.O.; Cherkashov, Yu.M.; Romenkov, A.A.

    1997-01-01

    This paper recommends the use of pool-type light water reactors for thermal energy production. Safety and reliability of these reactors were already demonstrated to the public by the long-term operation of swimming pool research reactors. The paper presents the design experience of two projects: Apatity Underground Nuclear Heating Plant and Nuclear Sea-Water Desalination Plant. The simplicity of pool-type reactors, the ease of their manufacturing and maintenance make this type of a heat source attractive to the countries without a developed nuclear industry. (author). 6 figs, 1 tab

  11. A theoretical prediction of critical heat flux in subcooled pool boiling during power transients

    International Nuclear Information System (INIS)

    Pasamehmetoglu, K.O.; Nelson, R.A.; Gunnerson, F.S.

    1988-01-01

    Understanding and predicting critical heat flux (CHF) behavior during steady-state and transient conditions are of fundamenatal interest in the design, operation, safety of boiling and two-phase flow devices. This paper discusses the results of a comprehensive theoretical study made specifically to model transient CHF behavior in subcooled pool boiling. This study is based upon a simplified steady-state CHF model in terms of the vapor mass growth period. The results obtained from this theory indicate favorable agreement with the experimental data from cylindrical heaters with small radii. The statistical nature of the vapor mass behavior in transient boiling also is considered and upper and lower limits for the current theory are established. Various factors that affect the discrepancy between the data and the theory are discussed

  12. Peak pool boiling heat flux from horizontal cylinders in subcooled liquids

    International Nuclear Information System (INIS)

    Elkassabgi, Y.

    1986-01-01

    The peak pool boiling heat flux is observed on horizontal cylindrical heaters in acetone, Freon-113, methanol, and isopropanol over ranges of subcooling from zero to 120 0 C. Photographs, and the data themselves, reveal that there are three distinct burnout mechanisms at different levels of subcooling. Three interpretive models provide the basis for accurate correlations of the present data, and data from the literature, in each of the three regimes. Burnout is dictated by condensation on the walls of the vapor jets and columns at low subcooling. In the intermediate regime, burnout is limited by natural convection which becomes very effective as vapor near the heater reduces boundary layer resistance. Burnout in the high-subcooling regime is independent of the level of subcoooling and is limited by the process of molecular effusion

  13. Swimming performance in surf: the influence of experience.

    Science.gov (United States)

    Tipton, M; Reilly, T; Rees, A; Spray, G; Golden, F

    2008-11-01

    This study tested the hypothesis (H1) that surf swimming involves a quantifiable experience component. Sixty-five beach lifeguards with (n = 35) and without surf experience (n = 30) completed: a best effort 200-m swim in a 25-m pool, a calm and a surf sea; an anthropometric survey; maximum effort 30-s swim bench test; 50-m pool swim (25 m underwater). In both groups, time to swim 200 m was slower in calm seas than in the pool and slower in surf than in either calm seas or the pool (p surf conditions (p surf experience as a predictor of surf swim time (R(2) = 0.32, p surf swimming. This limits the usefulness of pool swim times and other land-based tests as predictors of surf swimming performance. The hypothesis (H1) is accepted.

  14. Experimental investigation of heat transfer during severe accident of a Pressurized Heavy Water Reactor with simulated decay heat generation in molten pool inside calandria vessel

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Sumit Vishnu, E-mail: svprasad@barc.gov.in; Nayak, Arun Kumar, E-mail: arunths@barc.gov.in

    2016-07-15

    Highlights: • Scaled test facility simulating the calandria vessel and calandria vault water of PHWR with simulated decay heat was built. • Experiments conducted with simulant material at about 1200 °C. • Experimental result shows that melt coolability and growth rate of crust thickness are affected by presence of decay heat. • No gap was observed between the crust and vessel on opening. • Result shows that vessel integrity is intact with presence of water inside water tank in both cases. - Abstract: The present study focuses on experimental investigation in a scaled facility of an Indian PHWR to investigate the coolability of molten corium with simulated decay heat in the simulated calandria vessel. Molten borosilicate glass was used as the simulant due to its comparable heat transfer characteristics similar to prototypic material. About 60 kg of the molten material was poured into the test section at about 1200 °C. Decay heat in the melt pool was simulated using four high watt heaters cartridges, each having 9.2 kW. The temperature distributions inside the molten pool, across the vessel wall thickness and vault water were measured. Experimental results obtained are compared with the results obtained previously for no decay heat case. The results indicated that presence of decay heat seriously affects the coolability behaviour and formation of crust in the melt pool. The location and magnitude of maximum heat flux and surface temperature of the vessel also are affected in the presence of decay heat.

  15. Pregnant women maintain body temperatures within safe limits during moderate-intensity aqua-aerobic classes conducted in pools heated up to 33 degrees Celsius: an observational study

    Directory of Open Access Journals (Sweden)

    Amanda L Brearley

    2015-10-01

    Full Text Available Question: What is the body temperature response of healthy pregnant women exercising at moderate intensity in an aqua-aerobics class where the water temperature is in the range of 28 to 33 degrees Celsius, as typically found in community swimming pools? Design: An observational study. Participants: One hundred and nine women in the second and third trimester of pregnancy who were enrolled in a standardised aqua-aerobics class. Outcome measures: Tympanic temperature was measured at rest pre-immersion (T1, after 35 minutes of moderate-intensity aqua-aerobic exercise (T2, after a further 10 minutes of light exercise while still in the water (T3 and finally on departure from the facility (T4. The range of water temperatures in seven indoor community pools was 28.8 to 33.4 degrees Celsius. Results: Body temperature increased by a mean of 0.16 degrees Celsius (SD 0.35, p < 0.001 at T2, was maintained at this level at T3 and had returned to pre-immersion resting values at T4. Regression analysis demonstrated that the temperature response was not related to the water temperature (T2 r = –0.01, p = 0.9; T3 r = –0.02, p = 0.9; T4 r = 0.03, p = 0.8. Analysis of variance demonstrated no difference in body temperature response between participants when grouped in the cooler, medium and warmer water temperatures (T2 F = 0.94, p = 0.40; T3 F = 0.93, p = 0.40; T4 F = 0.70, p = 0.50. Conclusions: Healthy pregnant women maintain body temperatures within safe limits during moderate-intensity aqua-aerobic exercise conducted in pools heated up to 33 degrees Celsius. The study provides evidence to inform guidelines for safe water temperatures for aqua-aerobic exercise during pregnancy. [Brearley AL, Sherburn M, Galea MP, Clarke SJ, (2015 Pregnant women maintain body temperatures within safe limits during moderate-intensity aqua-aerobic classes conducted in pools heated up to 33 degrees Celsius: an observational study. Journal of

  16. Solar radiation, phytoplankton pigments and the radiant heating of the equatorial Pacific warm pool

    Science.gov (United States)

    Siegel, David A.; Ohlmann, J. Carter; Washburn, Libe; Bidigare, Robert R.; Nosse, Craig T.; Fields, Erik; Zhou, Yimei

    1995-01-01

    Recent optical, physical, and biological oceanographic observations are used to assess the magnitude and variability of the penetrating flux of solar radiation through the mixed layer of the warm water pool (WWP) of the western equatorial Pacific Ocean. Typical values for the penetrative solar flux at the climatological mean mixed layer depth for the WWP (30 m) are approx. 23 W/sq m and are a large fraction of the climatological mean net air-sea heat flux (approx. 40 W/sq m). The penetrating solar flux can vary significantly on synoptic timescales. Following a sustained westerly wind burst in situ solar fluxes were reduced in response to a near tripling of mixed layer phytoplankton pigment concentrations. This results in a reduction in the penetrative flux at depth (5.6 W/sq m at 30 m) and corresponds to a biogeochemically mediated increase in the mixed layer radiant heating rate of 0.13 C per month. These observations demonstrate a significant role of biogeochemical processes on WWP thermal climate. We speculate that this biogeochemically mediated feedback process may play an important role in enhancing the rate at which the WWP climate system returns to normal conditions following a westerly wind burst event.

  17. Geneva 24 hours swim

    CERN Multimedia

    2003-01-01

    The 18th edition of the Geneva 24 hours swim competition will take place at the Vernets Swimming Pool on the 4th and 5th of October. More information and the results of previous years are given at: http://www.carouge-natation.com/24_heures/home_24_heures.htm Last year, CERN obtained first position in the inter-company category with a total of 152.3 kms swam by 45 participants. We are counting on your support to repeat this excellent performance this year. For those who would like to train, the Livron swimming pool in Meyrin is open as from Monday the 8th September. For further information please do not hesitate to contact us. Gino de Bilio and Catherine Delamare

  18. Geneva 24 Hours Swim

    CERN Multimedia

    2003-01-01

    The 18th edition of the Geneva 24 hours swim competition will take place at the Vernets Swimming Pool on the 4th and 5th of October. More information and the results of previous years are given at: http://www.carouge-natation.com/24_heures/home_24_heures.htm Last year, CERN obtained first position in the inter-company category with a total of 152.3 kms swam by 45 participants. We are counting on your support to repeat this excellent performance this year. For those who would like to train, the Livron swimming pool in Meyrin is open as from Monday the 8th September. For further information please do not hesitate to contact us. Gino de Bilio and Catherine Delamare

  19. CO2 emissions and heat flow through soil, fumaroles, and steam heated mud pools at the Reykjanes geothermal area, SW Iceland

    International Nuclear Information System (INIS)

    Fridriksson, Thrainn; Kristjansson, Bjarni Reyr; Armannsson, Halldor; Margretardottir, Eygerour; Olafsdottir, Snjolaug; Chiodini, Giovanni

    2006-01-01

    Carbon dioxide emissions and heat flow through soil, steam vents and fractures, and steam heated mud pools were determined in the Reykjanes geothermal area, SW Iceland. Soil diffuse degassing of CO 2 was quantified by soil flux measurements on a 600 m by 375 m rectangular grid using a portable closed chamber soil flux meter and the resulting data were analyzed by both a graphical statistical method and sequential Gaussian simulations. The soil temperature was measured in each node of the grid and used to evaluate the heat flow. The heat flow data were also analyzed by sequential Gaussian simulations. Heat flow from steam vents and fractures was determined by quantifying the amount of steam emitted from the vents by direct measurements of steam flow rate. The heat loss from the steam heated mud pools was determined by quantifying the rate of heat loss from the pools by evaporation, convection, and radiation. The steam flow rate into the pools was calculated from the observed heat loss from the pools, assuming that steam flow was the only mechanism of heat transport into the pool. The CO 2 emissions from the steam vents and mud pools were determined by multiplying the steam flow rate from the respective sources by the representative CO 2 concentration of steam in the Reykjanes area. The observed rates of CO 2 emissions through soil, steam vents, and steam heated mud pools amounted to 13.5 ± 1.7, 0.23 ± 0.05, and 0.13 ± 0.03 tons per day, respectively. The heat flow through soil, steam vents, and mud pools was 16.9 ± 1.4, 2.2 ± 0.4, and 1.2 ± 0.1 MW, respectively. Heat loss from the geothermal reservoir, inferred from the CO 2 emissions through the soil amounts to 130 ± 16 MW of thermal energy. The discrepancy between the observed heat loss and the heat loss inferred from the CO 2 emissions is attributed to steam condensation in the subsurface due to interactions with cold ground water. These results demonstrate that soil diffuse degassing can be a more

  20. An analytic model of pool boiling critical heat flux on an immerged downward facing curved surface

    Energy Technology Data Exchange (ETDEWEB)

    He, Hui; Pan, Liang-ming, E-mail: cneng@cqu.edu.cn; Wu, Yao; Chen, De-qi

    2015-08-15

    Highlights: • Thin liquid film and supplement of liquid contribute to the CHF. • CHF increases from the bottom to the upper of the lowerhead. • Evaporation of thin liquid film is dominant nearby bottom region. • The subcooling has significant effects on the CHF. - Abstract: In this paper, an analytical model of the critical heat flux (CHF) on the downward facing curved surface for pool boiling has been proposed, which hypothesizes that the CHF on the downward facing curved is composed of two parts, i.e. the evaporation of the thin liquid film underneath the elongated bubble adhering to the lower head outer surface and the depletion of supplement of liquid due to the relative motion of vapor bubbles along with the downward facing curved. The former adopts the Kelvin–Helmholtz instability analysis of vapor–liquid interface of the vapor jets which penetrating in the thin liquid film. When the heat flux closing to the CHF point, the vapor–liquid interface becomes highly distorted, which block liquid to feed the thin liquid film and the thin liquid film will dry out gradually. While the latter considers that the vapor bubbles move along with the downward facing curved surface, and the liquid in two-phase boundary layer enter the liquid film that will be exhausted when the CHF occurs. Based on the aforementioned mechanism and the energy balance between the thin liquid film evaporation and water feeding, and taking the subcooling of the bulk water into account, the mathematic model about the downward facing curved surface CHF has been proposed. The CHF of the downward facing curved surface for pool boiling increases along with the downward facing orientation except in the vicinity of bottom center region, because in this region the vapor bubble almost stagnates and the evaporation of the thin liquid film is dominant. In addition, the subcooling has significant effect on the CHF. Comparing the result of this model with the published experimental results show

  1. Effective Momentum and heat flux models for simulation of stratification and mixing in a large pool of water

    Energy Technology Data Exchange (ETDEWEB)

    Hua Li; Villanueva, W.; Kudinov, P. [Royal Institute of Technology (KTH). Div. of Nuclear Power Safety, Stockholm (Sweden)

    2012-06-15

    Performance of a boiling water reactor (BWR) containment is mostly determined by reliable operation of pressure suppression pool which serves as a heat sink to cool and condense steam released from the core vessel. Thermal stratification in the pool can significantly impede the pool's pressure suppression capacity. A source of momentum is required in order to break stratification and mix the pool. It is important to have reliable prediction of transient development of stratification and mixing in the pool in different regimes of steam injection. Previously, we have proposed to model the effect of steam injection on the mixing and stratification with the Effective Heat Source (EHS) and the Effective Momentum Source (EMS) models. The EHS model is used to provide thermal effect of steam injection on the pool, preserving heat and mass balance. The EMS model is used to simulate momentum induced by steam injection in different flow regimes. The EMS model is based on the combination of (1) synthetic jet theory, which predicts effective momentum if amplitude and frequency of flow oscillations in the pipe are given, and (2) model proposed by Aya and Nariai for prediction of the amplitude and frequency of oscillations at a given pool temperature and steam mass flux. The complete EHS/EMS models only require the steam mass flux, initial pool bulk temperature, and design-specific parameters, to predict thermal stratification and mixing in a pressure suppression pool. In this work we use EHS/EMS models implemented in containment thermal hydraulic code GOTHIC. The POOLEX/PPOOLEX experiments (Lappeenranta University of Technology, Finland) are utilized, to (a) quantify errors due to GOTHIC's physical models and numerical schemes, (b) propose necessary improvements in GOTHIC sub-grid scale modeling, and (c) validate our proposed models. Specifically the data from POOLEX STB-21 and PPOOLEX STR-03 and STR-04 tests are used for validation of the EHS and EMS models in this

  2. Effective Momentum and heat flux models for simulation of stratification and mixing in a large pool of water

    International Nuclear Information System (INIS)

    Hua Li; Villanueva, W.; Kudinov, P.

    2012-06-01

    Performance of a boiling water reactor (BWR) containment is mostly determined by reliable operation of pressure suppression pool which serves as a heat sink to cool and condense steam released from the core vessel. Thermal stratification in the pool can significantly impede the pool's pressure suppression capacity. A source of momentum is required in order to break stratification and mix the pool. It is important to have reliable prediction of transient development of stratification and mixing in the pool in different regimes of steam injection. Previously, we have proposed to model the effect of steam injection on the mixing and stratification with the Effective Heat Source (EHS) and the Effective Momentum Source (EMS) models. The EHS model is used to provide thermal effect of steam injection on the pool, preserving heat and mass balance. The EMS model is used to simulate momentum induced by steam injection in different flow regimes. The EMS model is based on the combination of (1) synthetic jet theory, which predicts effective momentum if amplitude and frequency of flow oscillations in the pipe are given, and (2) model proposed by Aya and Nariai for prediction of the amplitude and frequency of oscillations at a given pool temperature and steam mass flux. The complete EHS/EMS models only require the steam mass flux, initial pool bulk temperature, and design-specific parameters, to predict thermal stratification and mixing in a pressure suppression pool. In this work we use EHS/EMS models implemented in containment thermal hydraulic code GOTHIC. The POOLEX/PPOOLEX experiments (Lappeenranta University of Technology, Finland) are utilized, to (a) quantify errors due to GOTHIC's physical models and numerical schemes, (b) propose necessary improvements in GOTHIC sub-grid scale modeling, and (c) validate our proposed models. Specifically the data from POOLEX STB-21 and PPOOLEX STR-03 and STR-04 tests are used for validation of the EHS and EMS models in this work. We

  3. Solar thermal heating and cooling. A bibliography with abstracts

    Science.gov (United States)

    Arenson, M.

    1979-01-01

    This bibliographic series cites and abstracts the literature and technical papers on the heating and cooling of buildings with solar thermal energy. Over 650 citations are arranged in the following categories: space heating and cooling systems; space heating and cooling models; building energy conservation; architectural considerations, thermal load computations; thermal load measurements, domestic hot water, solar and atmospheric radiation, swimming pools; and economics.

  4. Effects of surface orientation on nucleate boiling heat transfer in a pool of water under atmospheric pressure

    International Nuclear Information System (INIS)

    Jung, Satbyoul; Kim, Hyungdae

    2016-01-01

    Highlights: • Effects of surface inclination on pool boiling were experimentally examined. • Heat transfer and major bubble parameters were simultaneously measured. • A modified wall boiling model considering bubble merging was developed. • The presented model reasonably predicted pool boiling heat transfer on inclined surfaces. - Abstract: The basic wall boiling model widely used in computation fluid dynamics codes gives no regard to influences of surface orientation upon boiling mechanism. This study aims at examining the effects of surface orientation on wall heat flux and bubble parameters in pool nucleate boiling and incorporating those into the wall boiling model. Boiling experiments on a flat plate heater submerged in a pool of saturated water were conducted under atmospheric pressure. Relevant bubble parameters as well as boiling heat transfer characteristics were simultaneously measured using a unique optical setup integrating shadowgraph, total reflection and infrared thermometry techniques. It was observed that as an upward-facing heater surface with a constant wall superheat of 7.5 °C inclines from horizontal towards vertical, the heat flux significantly increased; nucleation site density increased intensively at the upper part of the heater surface where thermal boundary layer might become thickened; isolated boiling bubbles tend to slide up due to buoyancy and coalesce with each other, thus forming one single large bubble. Such observations on the wall heat flux and bubble parameters according to surface orientation could not be predicted by the present basic wall boiling model only centered with isolated bubbles. A modified wall boiling model incorporating the effects of merging of isolated bubbles on an inclined surface was proposed. The model reasonably predicted the experimental data on various orientation angles.

  5. Effects of surface orientation on nucleate boiling heat transfer in a pool of water under atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Satbyoul; Kim, Hyungdae, E-mail: hdkims@khu.ac.kr

    2016-08-15

    Highlights: • Effects of surface inclination on pool boiling were experimentally examined. • Heat transfer and major bubble parameters were simultaneously measured. • A modified wall boiling model considering bubble merging was developed. • The presented model reasonably predicted pool boiling heat transfer on inclined surfaces. - Abstract: The basic wall boiling model widely used in computation fluid dynamics codes gives no regard to influences of surface orientation upon boiling mechanism. This study aims at examining the effects of surface orientation on wall heat flux and bubble parameters in pool nucleate boiling and incorporating those into the wall boiling model. Boiling experiments on a flat plate heater submerged in a pool of saturated water were conducted under atmospheric pressure. Relevant bubble parameters as well as boiling heat transfer characteristics were simultaneously measured using a unique optical setup integrating shadowgraph, total reflection and infrared thermometry techniques. It was observed that as an upward-facing heater surface with a constant wall superheat of 7.5 °C inclines from horizontal towards vertical, the heat flux significantly increased; nucleation site density increased intensively at the upper part of the heater surface where thermal boundary layer might become thickened; isolated boiling bubbles tend to slide up due to buoyancy and coalesce with each other, thus forming one single large bubble. Such observations on the wall heat flux and bubble parameters according to surface orientation could not be predicted by the present basic wall boiling model only centered with isolated bubbles. A modified wall boiling model incorporating the effects of merging of isolated bubbles on an inclined surface was proposed. The model reasonably predicted the experimental data on various orientation angles.

  6. Analysis of the Processes in Spent Fuel Pools in Case of Loss of Heat Removal due to Water Leakage

    Directory of Open Access Journals (Sweden)

    Algirdas Kaliatka

    2013-01-01

    Full Text Available The safe storage of spent fuel assemblies in the spent fuel pools is very important. These facilities are not covered by leaktight containment; thus, the consequences of overheating and melting of fuel in the spent fuel pools can be very severe. On the other hand, due to low decay heat of fuel assemblies, the processes in pools are slow in comparison with processes in reactor core during LOCA accident. Thus, the accident management measures play a very important role in case of some accidents in spent fuel pools. This paper presents the analysis of possible consequences of fuel overheating due to leakage of water from spent fuel pool. Also, the accident mitigation measure, the late injection of water was evaluated. The analysis was performed for the Ignalina NPP Unit 2 spent fuel pool, using system thermal hydraulic code for severe accident analysis ATHLET-CD. The phenomena, taking place during such accident, are discussed. Also, benchmarking of results of the same accident calculation using ASTEC and RELAP/SCDAPSIM codes is presented here.

  7. Water Penetration into Middle Ear Through Ventilation Tubes in Children While Swimming

    Directory of Open Access Journals (Sweden)

    Mao-Che Wang

    2009-02-01

    Conclusion: Water penetration into the middle ear through ventilation tubes and middle ear infection are not likely when surface swimming. Children with ventilation tubes can enjoy swimming without protection in clean chlorinated swimming pools.

  8. Experimental investigation of heat transfer of R134a in pool boiling on stainless steel and aluminum tubes

    Science.gov (United States)

    Wengler, C.; Addy, J.; Luke, A.

    2018-03-01

    Due to high energy demand required for chemical processes, refrigeration and process industries the increase of efficiency and performance of thermal systems especially evaporators is indispensable. One of the possibilities to meet this purpose are investigations in enhancement of the heat transfer in nucleate boiling where high heat fluxes at low superheat are transferred. In the present work, the heat transfer in pool boiling is investigated with pure R134a over wide ranges of reduced pressures and heat fluxes. The heating materials of the test tubes are aluminum and stainless steel. The influence of the thermal conductivity on the heat transfer coefficients is analysed by the surface roughness of sandblasted surfaces. The heat transfer coefficient increases with increasing thermal conductivity, surface roughness and reduced pressures. The experimental results show a small degradation of the heat transfer coefficients between the two heating materials aluminum and stainless steel. In correlation with the VDI Heat Atlas, the experimental results are matching well with the predictions but do not accurately consider the stainless steel material reference properties.

  9. Analysis on the Role of RSG-GAS Pool Cooling System during Partial Loss of Heat Sink Accident

    Science.gov (United States)

    Susyadi; Endiah, P. H.; Sukmanto, D.; Andi, S. E.; Syaiful, B.; Hendro, T.; Geni, R. S.

    2018-02-01

    RSG-GAS is a 30 MW reactor that is mostly used for radioisotope production and experimental activities. Recently, it is regularly operated at half of its capacity for efficiency reason. During an accident, especially loss of heat sink, the role of its pool cooling system is very important to dump decay heat. An analysis using single failure approach and partial modeling of RELAP5 performed by S. Dibyo, 2010 shows that there is no significant increase in the coolant temperature if this system is properly functioned. However lessons learned from the Fukushima accident revealed that an accident can happen due to multiple failures. Considering ageing of the reactor, in this research the role of pool cooling system is to be investigated for a partial loss of heat sink accident which is at the same time the protection system fails to scram the reactor when being operated at 15 MW. The purpose is to clarify the transient characteristics and the final state of the coolant temperature. The method used is by simulating the system in RELAP5 code. Calculation results shows the pool cooling systems reduce coolant temperature for about 1 K as compared without activating them. The result alsoreveals that when the reactor is being operated at half of its rated power, it is still in safe condition for a partial loss of heat sink accident without scram.

  10. Contaminación del aire interior y del agua de baño en piscinas cubiertas de Guipúzcoa Indoor air and bathing water pollution in indoor swimming pools in Guipúzcoa (Spain

    Directory of Open Access Journals (Sweden)

    Loreto Santa Marina

    2009-04-01

    Full Text Available Objetivo: Describir los niveles de contaminantes presentes en las piscinas cubiertas de Guipúzcoa, tanto en el agua de baño como en el aire, y estudiar la relación entre estos contaminantes y otras variables relacionadas con los sistemas de ventilación y el uso de las instalaciones. Métodos: De las 35 piscinas cubiertas registradas en Guipúzcoa se estudiaron las 20 más utilizadas por nadadores. Cada instalación se muestreó 2 días no consecutivos y se midieron los niveles de cloro libre y combinado y trihalometanos en el agua, así como los de cloro total y cloroformo en el aire. Como indicador de la renovación del aire se midió el dióxido de carbono (CO2. Resultados: El nivel medio de cloro en el aire fue de 0,4mg/m³ y el de cloroformo de 22µg/m³. Los valores de cloro libre y combinado de todas las piscinas se mantuvieron dentro de los valores reglamentarios. El nivel medio de cloroformo del agua de baño fue de 13,7µg/l. El valor del cloroformo del aire puede predecirse razonablemente (R²=0,85, y las variables predictoras son el cloroformo del agua, el CO2 y el número de bañistas del día. Conclusiones: Los niveles de contaminantes en el agua y en el aire de las piscinas de Guipúzcoa son inferiores a los descritos en otros estudios. Sin embargo, utilizando la concentración de 0,5mg/m³ de cloro total en aire, propuesta como valor de referencia para la protección de los nadadores con actividad intensa, un 20% de las instalaciones superarían dicho valor.Objective: To describe levels of pollutants found in indoor swimming pools in Guipúzcoa (Basque Country, Spain, both in the bathing water and in the air, and to study the association between these pollutants and other variables related to ventilation systems and the use of installations. Methods: Of the 35 indoor swimming pools registered in Guipúzcoa, the 20 most frequently used by swimmers were studied. Each installation was sampled on two nonconsecutive days. Free and

  11. A model for the analysis of loss of decay heat removal accident in MTR pool type research reactors

    International Nuclear Information System (INIS)

    Bousbia-Salah, A.

    2005-01-01

    During a loss of coolant accident leading to total emptying of the reactor pool, the decay heat could be removed through air natural convection. However, under partial pool emptying the core is partially submerged and the coolant circulation inside the fuel element could no more be possible. In such conditions, a core overheat take place, and the heat is essentially diffused from the core to its periphery by combined thermal radiation and conduction. In order to predict fuel element temperature evolution under such conditions a mathematical model is performed. The model is based on a three dimensional geometry and takes into account a variety of core configurations including fuel elements (standard and control), reflector elements and grid plates. The homogeneous flow model is used and the time and space dependent non-linear partial differential fluid conservation equations are solved using a semi-implicit finite difference method. Preliminary tests of the developed model were made by considering a series of hypothetical accidents. In the current framework a loss of decay heat removal accidents in the IAEA benchmark open pool MTR-type research reactor is considered. It is shown that in the case of a low core immersion height no water boiling is observed and the fuel surface temperature rise remains below the melting point of the aluminium cladding. (author)

  12. Progressive Increase in Disinfection By-products and Mutagenicity from Source to Tap to Swimming Pool and Spa Water: Impact of Human Use

    Science.gov (United States)

    Pools and spas are enjoyed throughout the world for exercise and relaxation. However, there are no previous studies on mutagenicity of disinfected spa (hot tub) waters or comprehensive identification of disinfection byproducts (DBPs) formed in spas. Using 28 water samples from ...

  13. Effect of Tube Pitch on Pool Boiling Heat Transfer of Vertical Tube Bundle

    International Nuclear Information System (INIS)

    Kang, Myeong Gie

    2016-01-01

    Summarizing the previous results it can be stated that heat transfer coefficients are highly dependent on the tube pitch and the heat flux of the relevant tube. The published results are mostly about the horizontal tubes. However, there are many heat exchangers consisting of vertical tubes like AP600. Therefore, the focus of the present study is an identification of the effects of a tube pitch as well as the heat flux of a relevant tube on the heat transfer of a tube bundle installed vertically. When the heat flux is increased many bubbles are generating due to the increase of the nucleation sites. The bubbles become coalescing with the nearby bubbles and generates big bunches of bubbles on the tube surface. This prevents the access of the liquid to the surface and deteriorates heat transfer. The bubble coalescence is competing with the mechanisms enhancing heat transfer. The pitch was varied from 28.5 mm to 95 mm and the heat flux of the nearby tube was changed from 0 to 90kW/m 2 . The enhancement of the heat transfer is clearly observed when the heat flux of the nearby tube becomes larger and the heat flux of the upper tube is less than 40kW/m 2 . The effect of the tube pitch on heat transfer is negligible as the value of DP/ is increased more than 4.

  14. Swimming physiology.

    Science.gov (United States)

    Holmér, I

    1992-05-01

    Swimming takes place in a medium, that presents different gravitational and resistive forces, respiratory conditions and thermal stress compared to air. The energy cost of propulsion in swimming is high, but a considerable reduction occurs at a given velocity as result of regular swim training. In medley swimmers the energy cost is lowest for front crawl, followed by backstroke, butterfly and breast-stroke. Cardiac output is probably not limiting for performance since swimmers easily achieve higher values during running. Maximal heart rate, however, is lowered by approx. 10 beats/min during swimming compared to running. Most likely active muscle mass is smaller and rate of power production lesser in swimming. Local factors, such as peripheral circulation, capillary density, perfusion pressure and metabolic capacity of active muscles, are important determinants of the power production capacity and emphasize the role of swim specific training movements. Improved swimming technique and efficiency are likely to explain much of the continuous progress in performance. Rational principles based on improved understanding of the biomechanics and physiology of swimming should be guidelines for swimmers and coaches in their efforts to explore the limits of human performance.

  15. Heat transfer in a spent fuel pool concept containing PWR, Hybrid ADS-Fission, and VHTR spent fuels

    Energy Technology Data Exchange (ETDEWEB)

    Faria, Fernando P.; Cardoso, Fabiano; Salomé, Jean A.D.; Velasquez, Carlos E.; Pereira, Claubia, E-mail: fernandopereirabh@gmail.com, E-mail: fabinuclear@yahoo.com.br, E-mail: jadsalome@yahoo.com.br, E-mail: carlosvelcab@hotmail.com, E-mail: claubia@nuclear.ufmg.br [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    Thermal evaluation under wet storage conditions of spent fuels (SF) of the types UO{sub 2} discharged from Pressurized Water Reactor (PWR) and Very High-temperature Reactor (VHTR), and (Th,TRU)O{sub 2} from Accelerator-Driven Subcritical Reactor System (ADS) and VHTR are presented. The analyzes are in the absence of an external cooling system of the pool, and the goal is to compare the water boiling time of the pool storing these different types of SF, at time t=0 year after reactor discharge. Two techniques were implemented. In the first one, all the materials of the fuel elements are considered. In the second, the SF is treated as holes inside the pool, assuming the heat transfer directly from the SF to the water. Results from first technique show that the boiling time (T{sub b}) ranged from 23 minutes for (Th,TRU)O{sub 2} from VHTR to 3 hours for UO{sub 2} from VHTR, while for the second technique, T{sub b} ranged from 10 minutes for (Th,TRU)O{sub 2} from VHTR to 2.7 hours for UO{sub 2} from VHTR. The discrepancies between Tb from both techniques reveal that the pathways considered for the heat transfer are crucial to the results. The thermal studies used the module CFX of the ANSYS Workbench 16.2 - student version. (author)

  16. A dry-spot model of critical heat flux and transition boiling in pool and subcooled forced convection boiling

    International Nuclear Information System (INIS)

    Ha, Sang Jun

    1998-02-01

    A new dry-spot model for critical heat flux (CHF) is proposed. The new concept for dry area formation based on Poisson distribution of active nucleation sites and the critical active site number is introduced. The model is based on the boiling phenomena observed in nucleate boiling such as Poisson distribution of active nucleation sites and formation of dry spots on the heating surface. It is hypothesized that when the number of bubbles surrounding one bubble exceeds a critical number, the surrounding bubbles restrict the feed of liquid to the microlayer under the bubble. Then a dry spot of vapor will form on the heated surface. As the surface temperature is raised, more and more bubbles will have a population of surrounding active sites over the critical number. Consequently, the number of the spots will increase and the size of dry areas will increase due to merger of several dry spots. If this trend continues, the number of effective sites for heat transport through the wall will diminish, and CHF and transition boiling occur. The model is applicable to pool and subcooled forced convection boiling conditions, based on the common mechanism that CHF and transition boiling are caused by the accumulation and coalescences of dry spots. It is shown that CHF and heat flux in transition boiling can be determined without any empirical parameter based on information on the boiling parameters such as active site density and bubble diameter, etc., in nucleate boiling. It is also shown that the present model well represents actual phenomena on CHF and transition boiling and explains the mechanism on how parameters such as flow modes (pool or flow) and surface wettability influence CHF and transition boiling. Validation of the present model for CHF and transition boiling is achieved without any tuning parameter always present in earlier models. It is achieved by comparing the predictions of CHF and heat flux in transition boiling using measured boiling parameters in nucleate

  17. Water Evaporation in Swimming Baths

    DEFF Research Database (Denmark)

    Hyldgård, Carl-Erik

    This paper is publishing measuring results from models and full-scale baths of the evaporation in swimming baths, both public baths and retraining baths. Moreover, the heat balance of the basin water is measured. In addition the full-scale measurements have given many experiences which are repres...... are represented in instructions for carrying out and running swimming baths. If you follow the instructions you can achieve less investments, less heat consumption and a better comfort to the bathers....

  18. Steady-state nucleate pool boiling mechanism at low heat fluxes

    International Nuclear Information System (INIS)

    Bastos, L.E.G.

    1979-01-01

    Heat is transfered in the steady state to a horizontal cooper disc inmersed in water at saturation temperature. Levels of heat flux are controlled so that convection and the nucleate boiling can be observed. The value of heat flux is determined experimentally and high speed film is used to record bubble growth. In order to explain the phenomenon the oretical model is proposed in which part of the heat is transfered by free convection during nucleate boiling regime. Agreement between the experiments and the theoretical model is good. (Author) [pt

  19. Effect of Bottom Blockage on Heat Transfer in Single Equivalent Cooling Channel of a Spent Fuel Pool

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woo Ram; Lee, Jae Young [Handong Global University, Pohang (Korea, Republic of)

    2016-05-15

    In this study heat transfer in an equivalent fuel cooling channel was numerically studied to develop the basis for the study of a partially uncovered SFP. Transient characteristics of heating surface were analyzed under several boundary conditions. Partial uncover of SFP can arise from the boil off scenario under long term large scale station black out, or leakage of coolant by accident. It is expected that deterioration of heat transfer in a partially uncovered SFP can cause dramatic change of temperature field. Thermal circuit analysis was accompanied to explain trend of CFD results. Most cases were analyzed for tube heater, and soundness of it were well supported by fuel rod case. Bottom blockage hinders convective heat transfer. Therefore axially long and almost uniform hot zone is formed, contrary to developing temperature profile with low temperature gradient of opened bottom case. Moreover, if heat is vertically transferred, bottom blockage make dramatic increase of steady state temperature and temperature rising speed. As a result, for instance, amount of hydrogen generation can be largely varied by bottom blockage of spent fuel pool.

  20. Uncertainty analysis of suppression pool heating during an ATWS in a BWR-5 plant

    International Nuclear Information System (INIS)

    Wulff, W.; Cheng, H.S.; Mallen, A.N.; Johnsen, G.W.; Lellouche, G.S.

    1994-03-01

    The uncertainty has been estimated of predicting the peak temperature in the suppression pool of a BWR power plant, which undergoes an NRC-postulated Anticipated Transient Without Scram (ATWS). The ATWS is initiated by recirculation-pump trips, and then leads to power and flow oscillations as they had occurred at the LaSalle-2 Power Station in March of 1988. After limit-cycle oscillations have been established, the turbines are tripped, but without MSIV closure, allowing steam discharge through the turbine bypass into the condenser. Postulated operator actions, namely to lower the reactor vessel pressure and the level elevation in the downcomer, are simulated by a robot model which accounts for operator uncertainty. All balance of plant and control systems modeling uncertainties were part of the statistical uncertainty analysis that was patterned after the Code Scaling, Applicability and Uncertainty (CSAU) evaluation methodology. The analysis showed that the predicted suppression-pool peak temperature of 329.3 K (133 degrees F) has a 95-percentile uncertainty of 14.4 K (26 degrees F), and that the size of this uncertainty bracket is dominated by the experimental uncertainty of measuring Safety and Relief Valve mass flow rates under critical-flow conditions. The analysis showed also that the probability of exceeding the suppression-pool temperature limit of 352.6 K (175 degrees F) is most likely zero (it is estimated as < 5-104). The square root of the sum of the squares of all the computed peak pool temperatures is 350.7 K (171.6 degrees F)

  1. Modelling of convective-conductive heat transfer with phase change in an electrically heated UO2 pool

    International Nuclear Information System (INIS)

    Laval, H.; Giuliani, S.

    1985-01-01

    This paper describes an explicit finite element solution to transient conductive-convective heat transfer problems with phase change within an electrically heated region. The basic governing equations include the incompressible Navier-Stokes equations and the thermal energy equation. The phase change is modelled by a variant of the enthalpy method. Heat is generated by Joule effect due to the passage of an electric current for which a steady situation is assumed. An explicit scheme is used for the time integration, based on a fractional step method. A second-order Taylor-Galerkin method is introduced in the convection phase. The equations are discretized successively in space using the standard Galerkin finite element method. A reduced integration has been introduced as an option. In addition, a group representation is used for the non-linear velocity terms. To illustrate the proposed methodology, an application related to experimental tests is described. (orig.)

  2. Analysis of Transient Performance of KALIMER-600 Reactor Pool by Changing the Elevation of Intermediate Heat Exchanger

    International Nuclear Information System (INIS)

    Han, Ji Woong; Eoh, Jae Hyuk; Kim, Seong O

    2010-01-01

    The effect of increasing the elevation of an IHX (intermediate heat exchanger) on the transient performance of the KALIMER-600 reactor pool during the early phase of a loss of normal heat sink accident was investigated. Three reactors equipped with IHXs that were elevated to different heights were designed, and the thermal-hydraulic analyses were carried out for the steady and transient state by using the COMMIX-1AR/P code. In order to analyze the effects of the elevation of an IHX between reactors, various thermal-hydraulic properties such as mass flow rate, core peak temperature, RmfQ (ratio of mass flow over Q) and initiation time of decay heat removal via DHX (decay heat exchanger) were evaluated. It was found that with an increase in the IHX elevation, the circulation flow rate increases and a steep rise in the core peak temperature under the same coastdown flow condition is prevented without a delay in the initiation of the second stage of cooling. The available coastdown flow range in the reactor could be increased by increasing the elevation of the IHX

  3. Critical heat flux for downward-facing pool boiling on CANDU calandria tube surface

    Energy Technology Data Exchange (ETDEWEB)

    Behdadi, Azin, E-mail: behdada@mcmaster.ca; Talebi, Farshad; Luxat, John

    2017-04-15

    Highlights: • Pressure tube-calandria tube contact may challenge fuel channel integrity in CANDU. • Critical heat flux variation is predicted on the outer surface of CANDU calandria tube. • A two-phase boundary layer flow driven by buoyancy is modeled on the surface. • Different slip ratios and flow regimes are considered inside the boundary layer. • Subcooling effects are added to the model using wall heat flux partitioning. - Abstract: One accident scenario in CANDU reactors that can challenge the integrity of the primary pressure boundary is a loss of coolant accident, referred to as critical break LOCA, in which the pressure tube (PT) can undergo thermal creep strain deformation and contact its calandria tube (CT). In such case, rapid redistribution of stored heat from PT to CT, leads to a large spike in heat flux to the moderator which can cause bubble accumulation and dryout on the CT surface. A challenge to fuel channel integrity is posed if critical heat flux occurs on the surface of the CT and results in sustained film boiling. If the post-dryout temperature becomes sufficiently high then continued creep strain of the PT and CT may lead to fuel channel failure. In this study, a mechanistic model is developed to predict the critical heat flux variations along the downward facing outer surface of CT. The hydrodynamic model considers a liquid macrolayer beneath an elongated vapor slug on the surface. Local dryout is postulated to occur whenever the fresh liquid supply to the macrolayer is not sufficient to compensate for the liquid depletion. A boundary layer analysis is performed, treating the two phase motion as an external buoyancy driven flow. The model shows good agreement with the available experimental data and has been modified to take into account the effect of subcooling.

  4. Effects of Microencapsulated Phase Change Material (MPCM) on Critical Heat Flux in Pool Boiling

    International Nuclear Information System (INIS)

    Park, Sung Dae; Kim, Seong Man; Kang, Sarah; Lee, Seung Won; Seo, Han; Bang, In Cheol

    2011-01-01

    Thermal power is limited by critical heat flux (CHF) in the nuclear power plant. And the in-vessel retention by external reactor vessel cooling (IVR-ERVC) is applied in some nuclear power plants; AP600, AP1000, Loviisa and APR1400. The heat removal capacity of IVR-ERVC is also restricted by CHF. So, it is essential to get CHF margin to improve an economics and a safety of the plant. There are some typical approaches to enhance CHF: vibrating the heater or fluid, coating with porous media on the heater surface, applying an electric field. The recent study related to the CHF is focus on using the nanofluid. In this paper, the new approach was investigated by using the microencapsulated phase change material (MPCM). MPCM is the particles whose diameter is from 0.1μm to 1000μm. The MPCM consists of the core material and the shell material. The core material can be solid, liquid, gas or even the mixture. The solid paraffin is the best candidate as the core material due to its stable chemical and thermal properties. And the shell material is generally synthesized polymer of about several micrometers in thickness. The most interesting feature of the MPCM is that the latent heat associated with the solid-liquid phase change is related to the heat transfer. When the MPCM is dispersed into the carrier fluid, a kind of suspension named as microencapsulated phase change slurry (MPCS) is formed. The study on the MPCS was conducted in field of both the heat transfer fluids and energy storage media. It is inspired by the fact that the latent heat can serve distribution to the additional CHF margin. The purpose of this work is to confirm whether or not the CHF is enhanced

  5. An Enhanced VOF Method Coupled with Heat Transfer and Phase Change to Characterise Bubble Detachment in Saturated Pool Boiling

    Directory of Open Access Journals (Sweden)

    Anastasios Georgoulas

    2017-02-01

    Full Text Available The present numerical investigation identifies quantitative effects of fundamental controlling parameters on the detachment characteristics of isolated bubbles in cases of pool boiling in the nucleate boiling regime. For this purpose, an improved Volume of Fluid (VOF approach, developed previously in the general framework of OpenFOAM Computational Fluid Dynamics (CFD Toolbox, is further coupled with heat transfer and phase change. The predictions of the model are quantitatively verified against an existing analytical solution and experimental data in the literature. Following the model validation, four different series of parametric numerical experiments are performed, exploring the effect of the initial thermal boundary layer (ITBL thickness for the case of saturated pool boiling of R113 as well as the effects of the surface wettability, wall superheat and gravity level for the cases of R113, R22 and R134a refrigerants. It is confirmed that the ITBL is a very important parameter in the bubble growth and detachment process. Furthermore, for all of the examined working fluids the bubble detachment characteristics seem to be significantly affected by the triple-line contact angle (i.e., the wettability of the heated plate for equilibrium contact angles higher than 45°. As expected, the simulations revealed that the heated wall superheat is very influential on the bubble growth and detachment process. Finally, besides the novelty of the numerical approach, a last finding is the fact that the effect of the gravity level variation in the bubble detachment time and the volume diminishes with the increase of the ambient pressure.

  6. Reconstruction of local heat fluxes in pool boiling experiments using the entire heater geometry

    Energy Technology Data Exchange (ETDEWEB)

    Heng, Y.; Mhamdi, A.; Marquardt, W. [RWTH Aachen University, Aachen (Germany). AVT-Process Systems Engineering; Buchholz, M.; Auracher, H. [Berlin University of Technology (Germany). Inst. for Energy Engineering

    2009-07-01

    In this work, we consider the reconstruction of local boiling heat fluxes from high resolution transient temperature measurements inside the heater obtained during experiments performed at T U Berlin. In our previous work, a very small 3D domain surrounding the micro thermocouples at the center of a test heater has been considered. The unknown lateral boundary conditions have been set to zero, due to the lack of better knowledge. This geometry and the related assumptions have been chosen, due to the computational limitations. In the present study, we address for the first time this problem over the entire test heater. This has been only possible by improving the computational efficiency and using a suitable non-uniform discretization strategy. The boundary conditions in this study are well-defined at the boundaries where no boiling occurs. We formulate the heat flux estimation as a three-dimensional transient inverse heat conduction problem (IHCP). The solution of this ill-posed problem is obtained by applying an iterative regularization strategy, which is a combination of the method of conjugate gradients for the normal equation and the discrepancy principle. The obtained results are similar to those obtained in our previous work. The estimates are, however, much better in this work, since we not only recover the dynamics of the signal, but also largely avoid the negative heat fluxes, which we observed using the much smaller region. (author)

  7. Simulation of Wickless-Heat Pipe as Passive Cooling System in Nuclear Spent Fuel Pool Using RELAP5/MOD3.2

    OpenAIRE

    Kusuma, Mukhsinun Hadi; Putra, Nandy; Ismarwanti, Sri; Widodo, Surip

    2017-01-01

    The lesson learned from the severe accident of Fukushima Daiichi nuclear power plant shows that the residual heat generated from nuclear spent fuel should be cooled properly. In order to absorb that residual heat when station blackout occurs, wickless-heat pipe is proposed to be used as an alternative of the passive cooling system in nuclear spent fuel pool. The objective of this research is to simulation the effect of initial pressure and evaporator filling ratio as factors that influence th...

  8. Training optimization of swimming of school-age children

    OpenAIRE

    Hudcová, Stanislava

    2011-01-01

    Subject matter: Training optimization of swimming of school-age children Objectives: The main goal of this research work is to suggest a model of advanced swimming training lessons with school-age children. Swimming training is practised in deep swimming pool. Next goal is to create an inventory of games and game disciplines which are suitable for training in deep water. Through the analysis of specialized literature and realization of experimental education we will be able to formulate new p...

  9. Under-ice eddy covariance flux measurements of heat, salt, momentum, and dissolved oxygen in an artificial sea ice pool

    DEFF Research Database (Denmark)

    Else, B. G T; Rysgaard, S.; Attard, K.

    2015-01-01

    Turbulent exchanges under sea ice play a controlling role in ice mass balance, ice drift, biogeochemistry, and mixed layer modification. In this study, we examined the potential to measure under-ice turbulent exchanges of heat, salt, momentum, and dissolved oxygen using eddy covariance...... in an experimental sea ice facility. Over a 15-day period in January 2013, an underwater eddy covariance system was deployed in a large (500 m3) inground concrete pool, which was filled with artificial seawater and exposed to the ambient (−5 to −30 °C) atmosphere. Turbulent exchanges were measured continuously...... initial ice growth were directed upward at 10 to 25 W m−2. Dissolved oxygen fluxes were directed downward at rates of 5 to 50mmolm−2 d−1 throughout the experiment, at times exceeding the expected amount of oxygen rejected with the brine during ice growth. Bubble formation and dissolution was identified...

  10. Modelling of the spent fuel heat-up in the spent fuel pools using one-dimensional system codes and CFD codes

    Energy Technology Data Exchange (ETDEWEB)

    Grazevicius, Audrius; Kaliatka, Algirdas [Lithuanian Energy Institute, Kaunas (Lithuania). Lab. of Nuclear Installation Safety

    2017-07-15

    The main functions of spent fuel pools are to remove the residual heat from spent fuel assemblies and to perform the function of biological shielding. In the case of loss of heat removal from spent fuel pool, the fuel rods and pool water temperatures would increase continuously. After the saturated temperature is reached, due to evaporation of water the pool water level would drop, eventually causing the uncover of spent fuel assemblies, fuel overheating and fuel rods failure. This paper presents an analysis of loss of heat removal accident in spent fuel pool of BWR 4 and a comparison of two different modelling approaches. The one-dimensional system thermal-hydraulic computer code RELAP5 and CFD tool ANSYS Fluent were used for the analysis. The results are similar, but the local effects cannot be simulated using a one-dimensional code. The ANSYS Fluent calculation demonstrated that this three-dimensional treatment allows to avoid the need for many one-dimensional modelling assumptions in the pool modelling and enables to reduce the uncertainties associated with natural circulation flow calculation.

  11. Enhanced pool boiling critical heat flux induced by capillary wicking effect of a Cr-sputtered superhydrophilic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hong Hyun; Seo, Gwang Hyeok; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

    2016-10-15

    In light of boiling heat transfer, the smooth surface potentially reduces active nucleation of bubbles and rewetting of dry spots near the critical heat flux (CHF). This kind of process is highly likely to deteriorate the CHF. Thus, it is essential to produce appropriate microstructures on the surface for the enhancement of the CHF. In this study, to investigate the microstructural effect of thin film-fabricated surfaces on the pool boiling CHF, we controlled the surface roughness in a narrow range of 0.1-0.25 μm and its morphologies, in the form of micro-scratches using PVD sputtering technique. Specifically for DC magnetron sputtering, pure chromium (Cr) was selected as a target material owing to its high oxidation resistance. In order to analyze the CHF trend with changes in roughness, we introduced existing capillary wicking-based models because superhydrophilic characteristics of microstructures are highly related to the capillary wicking behaviors in micro-flow channels. After Cr sputtering under given conditions, the Cr-sputtered surfaces showed superhydrophilic characteristics and its capability became more enhanced with an increase of surface roughness. Judging from spreading behavior of a liquid droplet, the presence of micro-wicking channels, coupled with Cr nanostructures, effectively enhanced the advancing rate of drop base diameter. The CHF exhibited an increasing trend with increasing surface roughness. However, the enhancement ratio agreed poorly with the predictions of the roughness factor-based models, all of which originated from a conventional static force balance.

  12. A computational model for viscous fluid flow, heat transfer, and melting in in situ vitrification melt pools

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, P.R.; Ramshaw, J.D.

    1991-11-01

    MAGMA is a FORTRAN computer code designed to viscous flow in in situ vitrification melt pools. It models three-dimensional, incompressible, viscous flow and heat transfer. The momentum equation is coupled to the temperature field through the buoyancy force terms arising from the Boussinesq approximation. All fluid properties, except density, are assumed variable. Density is assumed constant except in the buoyancy force terms in the momentum equation. A simple melting model based on the enthalpy method allows the study of the melt front progression and latent heat effects. An indirect addressing scheme used in the numerical solution of the momentum equation voids unnecessary calculations in cells devoid of liquid. Two-dimensional calculations can be performed using either rectangular or cylindrical coordinates, while three-dimensional calculations use rectangular coordinates. All derivatives are approximated by finite differences. The incompressible Navier-Stokes equations are solved using a new fully implicit iterative technique, while the energy equation is differenced explicitly in time. Spatial derivatives are written in conservative form using a uniform, rectangular, staggered mesh based on the marker and cell placement of variables. Convective terms are differenced using a weighted average of centered and donor cell differencing to ensure numerical stability. Complete descriptions of MAGMA governing equations, numerics, code structure, and code verification are provided. 14 refs.

  13. A computational model for viscous fluid flow, heat transfer, and melting in in situ vitrification melt pools

    International Nuclear Information System (INIS)

    McHugh, P.R.; Ramshaw, J.D.

    1991-11-01

    MAGMA is a FORTRAN computer code designed to viscous flow in in situ vitrification melt pools. It models three-dimensional, incompressible, viscous flow and heat transfer. The momentum equation is coupled to the temperature field through the buoyancy force terms arising from the Boussinesq approximation. All fluid properties, except density, are assumed variable. Density is assumed constant except in the buoyancy force terms in the momentum equation. A simple melting model based on the enthalpy method allows the study of the melt front progression and latent heat effects. An indirect addressing scheme used in the numerical solution of the momentum equation voids unnecessary calculations in cells devoid of liquid. Two-dimensional calculations can be performed using either rectangular or cylindrical coordinates, while three-dimensional calculations use rectangular coordinates. All derivatives are approximated by finite differences. The incompressible Navier-Stokes equations are solved using a new fully implicit iterative technique, while the energy equation is differenced explicitly in time. Spatial derivatives are written in conservative form using a uniform, rectangular, staggered mesh based on the marker and cell placement of variables. Convective terms are differenced using a weighted average of centered and donor cell differencing to ensure numerical stability. Complete descriptions of MAGMA governing equations, numerics, code structure, and code verification are provided. 14 refs

  14. Strategies for chemically healthy public swimming pools

    OpenAIRE

    Hansen, Kamilla Marie Speht; Andersen, Henrik Rasmus; Albrechtsen, Hans-Jørgen; Mosbæk, Hans

    2013-01-01

    I Danmark er offentlige svømmebade en vigtig mulighed for rekreative aktiviteter og fysisk træning samt et redskab for genoptræning. Tilsætning af klor anvendes altid til at kontrollere vand¬kvaliteten og hindre spredning af infektioner mellem badende. Klor oxiderer vandforureningen fra de badende, hvilket holder bassinvandet rent, men der dannes klorerede desinfektions¬biprodukter. Der er identificeret mere end 100 klorbiprodukter i svømme¬bads¬vand, hvor nogle har vist sig at være genotoksi...

  15. Is swimming during pregnancy a safe exercise?

    DEFF Research Database (Denmark)

    Juhl, Mette; Kogevinas, Manolis; Andersen, Per Kragh

    2010-01-01

    BACKGROUND: Exercise in pregnancy is recommended in many countries, and swimming is considered by many to be an ideal activity for pregnant women. Disinfection by-products in swimming pool water may, however, be associated with adverse effects on various reproductive outcomes. We examined...... the association between swimming in pregnancy and preterm and postterm birth, fetal growth measures, small-for-gestational-age, and congenital malformations. METHODS: We used self-reported exercise data (swimming, bicycling, or no exercise) that were prospectively collected twice during pregnancy for 74......,486 singleton pregnancies. Recruitment to The Danish National Birth Cohort took place 1996-2002. Using Cox, linear and logistic regression analyses, depending on the outcome, we compared swimmers with physically inactive pregnant women; to separate a possible swimming effect from an effect of exercise...

  16. Improving Pool Fencing Legislation in Queensland, Australia: Attitudes and Impact on Child Drowning Fatalities.

    Science.gov (United States)

    Franklin, Richard C; Peden, Amy E

    2017-11-24

    Four-sided, non-climbable pool fencing is an effective strategy for preventing children from drowning in home swimming pools. In 2009, the Queensland Government introduced legislation to improve the effectiveness of pool fencing. This study explores community attitudes towards the effectiveness of these legislative changes and examines child (houses with swimming pools) are protected.

  17. An Innovative Passive Residual Heat Removal System of an Open-Pool Type Research Reactor with Pump Flywheel and Gravity Core Cooling Tank

    Directory of Open Access Journals (Sweden)

    Kwon-Yeong Lee

    2015-01-01

    Full Text Available 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.

  18. A preliminary design study of a pool-type FBR 'ARES' eliminating intermediate heat transport systems

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, N.; Nishi, Y.; Kinoshita, I.; Yoshida, K. [Central Research Institute of Electric Power Industry, Komae Research Lab., Nuclear Systems Dept., Tokyo (Japan)

    2001-07-01

    An innovative reactor concept 'ARES' (Advanced Reactor Eliminating Secondary system) is proposed to aim at reducing the construction cost of a liquid metal cooled fast breeder reactor (LMFBR). This concept is developed to show the ultimate cost down potential of LMFBR's at their commercial stage. The electrical output is 1500 MW, while the thermal output is 3900 MW. Main components of the primary cooling system are four electromagnetic pumps (EMP) and eight double-wall-tube steam generators (SG). Both of them are installed in a reactor vessel like pool type LMFBR's. An intermediate heat transport system which a previous LMFBR has it eliminated, main components of which are intermediate heat exchangers (IHX), secondary pumps and secondary piping. Further, a high reliable SG could decrease the occurrence of water leak accidents and reduce the related mitigation systems. In this study, structure concept, approach to embody a high reliable SG and accidents analyses are carried out. Flow path configuration is mainly discussed in investigation of the structure concept. In case of a water leak accident in a SG, the fault SG must be isolated to prevent a reaction production from flowing into the core. The measure to cut both inlet and outlet coolant flow paths by siphon-break mechanism is adopted to be consistent with the decay heat removal operation. The safety design approach of the double-wall-tube SG is investigated to limit the accident occurrence below 10{sup -7} (1/ry). A tube-to-tube weld is excluded from the reference design, because the welding process is too difficult and complicated to prevent adhesion of the double-wall-tube effectively. The reliability of the tube-to-tube-sheet was evaluated as 10{sup -10} (1/hr) for an inner tube and 10{sup -9} (1/hr) for an outer tube with reference to the failure experience of previous SG's. The failure must be detected within 60 to 120 minutes. Finally, a seamless U tube type of double

  19. Study of the hovering period and bubble size in fully developed pool nucleate boiling of saturated liquid with a time-dependent heat source

    International Nuclear Information System (INIS)

    Pasamehmetoglu, K.O.; Nelson, R.A.

    1987-01-01

    In this paper, the bubble behavior in saturated pool boiling with a time-dependent heat source is analyzed. The study is restricted to the period from fully developed nucleate boiling until critical heat flux occurs. The hovering period and the departure volume of the bubble are selected as the characteristic parameters for bubble behavior. These parameters are quantified by solving the equation of motion for an idealized bubble. This equation is solved for cases in which the surface heat flux changes linearly and exponentially as a function of time. After nondimensionalization, the results are compared directly with the results of the steady-state problem. The comparison shows that the transient heat input has practically no effect on the hovering period. However, the transient heat flux causes a decreased volume at bubble departure. The volume decrease is dependent on the severity of the transient. These results are in qualitative agreement with the experimental observation quoted in the literature

  20. The impact of Atlas Mountain cold-pool events on the position and intensity of the summertime West African heat low

    Science.gov (United States)

    Schuster, Robert; Fink, Andreas H.; Knippertz, Peter; Marsham, John H.; Parker, Douglas J.; Flamant, Cyrille

    2014-05-01

    Recently discovered fluctuations of the summertime West African heat low on different time scales are still not fully understood, but of major importance for an improved prediction of the West African Monsoon system in weather and climate models. It has recently been demonstrated that the cold-pool outflows from convection form a significant component of the West African monsoon and that in a global model the failure to represent these adequately is a major cause of thermodynamic model-bias in the monsoon-ventilated heat-low region. Here we focus on the extratropical flank of the heat low, which often reaches to the Saharan foothills of the Atlas Mountains in Morocco and Algeria during the summer months. Strong, often orographically triggered convective events over the Atlas Mountains and at their southern flanks are a regularly observed feature during this time. Such events are often associated with evaporatively driven cold-pools, resulting in haboob dust storms in the Saharan Desert. The leading edge of these density currents can reach lengths of several hundreds to a thousand kilometres; its movement is visible on satellite images for up to twelve hours and affects the core region of the heat low. Significant amounts of moisture are transported into the desert this way and can lead to the production of new convective systems there. We use the Weather Research and Forecast (WRF) model driven by the operational analysis of the European Centre for Medium-Range Weather Forecasting (ECMWF) to investigate the impact of these events on the positions and strength of the heat low in convection-permitting simulations. The aim is to improve the understanding of the involved processes and to quantify the errors that are expected in models that are not able to generate cold pools effectively due to their parametrisations of moist convection. The cases used for this study have been selected based on station measurements and on infrared as well as microwave satellite data

  1. PROPERTIES OF SWIMMING WATER

    Directory of Open Access Journals (Sweden)

    Tayfun KIR

    2004-10-01

    Full Text Available Swimming waters may be hazardous on human health. So, The physicians who work in the facilities, which include swimming areas, are responsible to prevent risks. To ensure hygiene of swimming water, European Swimming Water Directive offers microbiological, physical, and chemical criteria. [TAF Prev Med Bull 2004; 3(5.000: 103-104

  2. Protocol of actuation before occurrence of 'molluscum contagiosum' for use in public swimming pools Protocolo de actuación ante la aparición de casos de molusco contagioso en piscinas de uso público

    Directory of Open Access Journals (Sweden)

    José Ángel Bautista Cotorruelo

    2008-12-01

    Full Text Available The main objective is to develop a protocol for the disinfection of episodes of Molluscum contagiosum and establish an objective indicator. Molluscum contagiosum is a virus of Poxviridae Family. This virus produces a common infection in children that occurs when they come into direct contact with a lesion or with contaminated objects. In November 2008 is received at the Servicio de Sanidad Ambiental (Dirección General de Salud Pública, Consejería de Sanidad y Consumo, Comunidad Autónoma de la Región de Murcia a telephone call from the Epidemiology Service, which reported the existence of about 12-15 cases of children affected by Molluscum contagiosum. In addition, they indicated us that the suspicions fell on the Municipal Pool Cover Alhama de Murcia. Immediately we contacted the responsible staff and we send them a protocol developed with information from several sources. The analysis of articles used for water activities showed absence of Molluscum contagiosum. We selected "absence of molds and yeasts” as indicator. All this coincided with the disappearance of the cases. Months later, in March 2009 we detected new cases of children affected in another pool in the town of Alcantarilla. Due to the success of the methodology used in the earlier incident we performed the same actions and we obtained the same results. The protocol developed by this Service is effective to avoid the occurrence of more cases. We propose the “absence of molds and yeasts” as an indicator to evaluate the presence of Molluscum contagiosum. Coinciding with the update of the rules of public swimming pools in our Region we have introduced an article that indicates that the objects used for water activities must be disinfected after each use.El objetivo principal fue elaborar un protocolo de actuación para el caso de episodios de infección de molusco contagioso y un indicador objetivo, que nos permita hacer un seguimiento. El virus del molusco contagioso

  3. Efeitos de oito semanas de treinamento de natação no limiar anaeróbio determinado na piscina e no ergômetro de braço Effect of eight weeks of swimming training on the anaerobic threshold determined in the swimming pool and by arm ergometer

    Directory of Open Access Journals (Sweden)

    Fabrizio Caputo

    2002-02-01

    Full Text Available O objetivo deste estudo foi analisar os efeitos do treinamento de natação na intensidade do limiar anaeróbio (LAn, determinado na piscina e no ergômetro de braço, verificando se este pode ser utilizado para avaliar os efeitos do treinamento em nadadores. Participaram do estudo sete nadadores de ambos os sexos, com nível de performance regional, que foram submetidos aos seguintes testes, antes e após oito semanas de treinamento: 1 dois tiros de 400m, um a 85% e outro a 95% do máximo, com coleta de 25mil de sangue do lóbulo da orelha no 1º, 3º e 5º minuto após cada tiro, para posterior análise do lactato sanguíneo (YSI 1500; 2 teste contínuo progressivo realizado no ergômetro de braço (UBE 2462 Cybex, com carga inicial de 33,3W e incrementos de 16,6W a cada três minutos até a exaustão voluntária, com coleta de sangue ao final de cada estágio. Um grupo controle de indivíduos não ativos (n = 9, que se manteve sedentário, realizou somente o procedimento 2 no mesmo intervalo de tempo. O LAn na natação (NLAn e no ergômetro de braço (BLAn foi encontrado através de interpolação linear, considerando uma concentração fixa de lactato de 4mM e 3,5mM, respectivamente. Os resultados demonstram diferença significante para o grupo treinado, entre o pré (130,4 ± 20,4W e o pós-teste (137,7 ± 17,9W para o BLAn. Porém, não foi encontrada diferença significante para o NLAn (1,09 ± 0,1m.s-1 e 1,13 ± 0,1m.s-1, p = 0,06. No grupo controle não foi encontrada diferença para o BLAn entre o pré (93,2 ± 11,5W e o pós-teste (87,7 ± 7,2W. Pode-se concluir através desses dados que a determinação do LAn no ergômetro de braço é útil para detectar adaptações na capacidade aeróbia de nadadores com nível de performance regional.The objective of this study was to analyze the effect of swimming training on the intensity corresponding to the anaerobic threshold (AnT determined in the swimming pool and by arm ergometer, and

  4. Experimental assessment on the thermal effects of the neutron shielding and heat-transfer fin of dual purpose casks on open pool fire

    International Nuclear Information System (INIS)

    Bang, Kyoung-Sik; Yu, Seung-Hwan; Lee, Ju-Chan; Seo, Ki-Seog; Choi, Woo-Seok

    2016-01-01

    Highlights: • An open pool fire test was performed to estimate not only the combustion effect of the neutron shielding but also the effect of the heat transfer fin of the dual purpose cask. • The heat transfer to the inside of the dual purpose cask was reduced, when the neutron shielding burns. • The surface temperatures are lower in the present of the heat transfer fins. • If inflammable material is used as the components of the cask, evaluating thermal integrity using the thermal test would be desirable. - Abstract: Dual purpose casks are used for storage and transport of spent nuclear fuel assemblies. They must therefore satisfy the requirements prescribed in the Korea Nuclear Safety Security Commission Act 2014-50, the IAEA Safety Standard Series No. SSR-6, and US 10 CFR Part 71. These regulatory guidelines classify the dual purpose cask as a Type B package and state that a Type B package must be able to withstand a temperature of 800 °C for a period of 30 min. NS-4-FR is used as neutron shielding of the dual purpose cask. Heat transfer fins are embedded to enhance heat transfer from the cask body to the outer-shell because the thermal conductivity of NS-4-FR is not good. However, accurately simulating not only the combustion effect of the neutron shielding but also the effect of the heat transfer fin in the thermal analysis is not easy. Therefore, an open pool fire test was conducted using a one-sixth slice of a real cask to estimate these effects at a temperature of 800 °C for a period of 30 min. The temperature at the central portion of the neutron shielding was lower when the neutron shielding in contact with the outer cask burned because the neutron shielding absorbed the surrounding latent heat as the neutron shielding burned. Therefore, the heat transfer to the inside of the dual purpose cask was reduced. The surface temperature was lower when a heat transfer fin was installed because the high heat generated by the flame was transferred to the

  5. EFFECTS OF THREE FEEDBACK CONDITIONS ON AEROBIC SWIM SPEEDS

    Directory of Open Access Journals (Sweden)

    Pedro Pérez Soriano

    2009-03-01

    Full Text Available The purpose of this study was twofold: (a to develop an underwater chronometer capable to provide feedback while the athlete is swimming, as well as being a control tool for the coach, and (b to analyse its feedback effect on swim pace control compared with feedback provided by the coach and with no feedback, in 25 m and 50 m swimming pools. 30 male swimmers of national level volunteer to participate. Each swimmer swam 3 x 200 m at aerobic speed (AS and 3 x 200 m just under the anaerobic threshold speed (AnS, each swam repetition with a different feedback condition: chronometer, coach and without feedback. Results (a validate the chronometer system developed and (b show that swimmers pace control is affected by the type of feedback provided, the swim speed elected and the size of the swimming pool

  6. ARC Code TI: Swim

    Data.gov (United States)

    National Aeronautics and Space Administration — Swim is a software information service for the grid built on top of Pour, which is an information service framework developed at NASA. Swim provides true software...

  7. Laryngoscopy during swimming

    DEFF Research Database (Denmark)

    Walsted, Emil S; Swanton, Laura L; van van Someren, Ken

    2017-01-01

    that precipitates their symptoms. This report provides the first description of the feasibility of performing continuous laryngoscopy during exercise in a swimming environment. The report describes the methodology and safety of the use of continuous laryngoscopy while swimming. Laryngoscope, 2017....

  8. SWIMMING CLASSES IN JUNIOR HIGH SCHOOL STUDENTS’ OPINION

    Directory of Open Access Journals (Sweden)

    Grzegorz Bielec

    2013-02-01

    Full Text Available The role of modern physical education is not only to develop motor abilities of the students, but most of all prevent them from epidemic youth diseases such as obesity or postural defects. Positive attitudes to swimming as a long-life physical activity, instilled in adolescence should be beneficial in adult life. The group of 130 boys and 116 girls of 7th grade junior high school (mean age 14.6 was asked in the survey to present their opinion of obligatory swimming lessons at school. Students of both sexes claimed that they liked swimming classes because they could improve their swimming skills (59% of answers and because of health-related character of water exercises (38%. 33% of students regarded swimming lessons as boring and monotonous, and 25% of them complained about poor pool conditions like chlorine smell, crowded lanes, too low temperature. Majority of the surveyed students saw practical role of swimming in saving others life.

  9. A generic study of phenomena affecting two-phase mixing in BWR suppression pools during passive decay-heat removal

    International Nuclear Information System (INIS)

    Smith, B. L.; Milelli, M.; Shepel, S.; Lakehal, D.

    2003-01-01

    The paper describes some advancements made in the use of two-phase Computational Fluid Dynamics (CFD), sometimes called Computational Multi-Fluid Dynamics (CMFD), techniques in simulating the phenomena occurring in pressure suppression pools in Advanced Boiling Water Reactors which utilise passive containment cooling systems. An interface tracking procedure based on the Level-Set approach has been implemented into a commercial CFD code with the specific purpose of providing a computational environment for the development of suitable models to describe the inter-phase mass and energy transport processes which would take place when a large gas bubble is discharged into a pool. Details of the implementation and validation of the tracking algorithm are described, together with some illustrations of how the method is utilised. The paper also reports on the progress which is being made in the use of Large-Eddy Simulation (LES) to describe turbulent mixing in such plumes. The research efforts are aimed at ultimately combining the approaches to develop a mechanistic tool for fully describing the pool dynamics and steam condensation phenomena

  10. Elite sprint swimming performance is enhanced by completion of additional warm-up activities.

    Science.gov (United States)

    McGowan, Courtney J; Pyne, David B; Thompson, Kevin G; Raglin, John S; Osborne, Mark; Rattray, Ben

    2017-08-01

    This study investigated the effect of completing additional warm-up strategies in the transition phase between the pool warm up and the start of a race on elite sprint swimming performance. Twenty-five elite swimmers (12 men, 20 ± 3 years; 13 women, 20 ± 2 years, performance standard ~807 FINA2014 points) completed a standardised pool warm up followed by a 30-min transition phase and a 100-m freestyle time trial. During the transition phase, swimmers wore a tracksuit jacket with integrated heating elements and performed a dry land-based exercise routine (Combo), or a conventional tracksuit and remained seated (Control). Start (1.5% ± 1.0%, P = 0.02; mean ± 90% confidence limits) and 100-m time trial (0.8% ± 0.4%, P heating via heated jackets and completion of dry land-based exercises in the transition phase improves elite sprint swimming performance by ~0.8%.

  11. Swimming Safely (A Minute of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2014-05-22

    Almost 4,000 people die from drowning each year in the U.S. You can also get sick at the pool. This podcast discusses swimming pool safety tips.  Created: 5/22/2014 by MMWR.   Date Released: 5/22/2014.

  12. Simulation of decay heat removal by natural convection in a pool type fast reactor model-ramona-with coupled 1D/2D thermal hydraulic code system

    Energy Technology Data Exchange (ETDEWEB)

    Kasinathan, N.; Rajakumar, A.; Vaidyanathan, G.; Chetal, S.C. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    1995-09-01

    Post shutdown decay heat removal is an important safety requirement in any nuclear system. In order to improve the reliability of this function, Liquid metal (sodium) cooled fast breeder reactors (LMFBR) are equipped with redundant hot pool dipped immersion coolers connected to natural draught air cooled heat exchangers through intermediate sodium circuits. During decay heat removal, flow through the core, immersion cooler primary side and in the intermediate sodium circuits are also through natural convection. In order to establish the viability and validate computer codes used in making predictions, a 1:20 scale experimental model called RAMONA with water as coolant has been built and experimental simulation of decay heat removal situation has been performed at KfK Karlsruhe. Results of two such experiments have been compiled and published as benchmarks. This paper brings out the results of the numerical simulation of one of the benchmark case through a 1D/2D coupled code system, DHDYN-1D/THYC-2D and the salient features of the comparisons. Brief description of the formulations of the codes are also included.

  13. The Effective Convectivity Model for Simulation and Analysis of Melt Pool Heat Transfer in a Light Water Reactor Pressure Vessel Lower Head

    International Nuclear Information System (INIS)

    Tran, Chi Thanh

    2009-09-01

    Severe accidents in a Light Water Reactor (LWR) have been a subject of intense research for the last three decades. The research in this area aims to reach understanding of the inherent physical phenomena and reduce the uncertainties in their quantification, with the ultimate goal of developing models that can be applied to safety analysis of nuclear reactors, and to evaluation of the proposed accident management schemes for mitigating the consequences of severe accidents. In a hypothetical severe accident there is likelihood that the core materials will be relocated to the lower plenum and form a decay-heated debris bed (debris cake) or a melt pool. Interactions of core debris or melt with the reactor structures depend to a large extent on the debris bed or melt pool thermal hydraulics. In case of inadequate cooling, the excessive heat would drive the structures' overheating and ablation, and hence govern the vessel failure mode and timing. In turn, threats to containment integrity associated with potential ex-vessel steam explosions and ex-vessel debris uncoolability depend on the composition, superheat, and amount of molten corium available for discharge upon the vessel failure. That is why predictions of transient melt pool heat transfer in the reactor lower head, subsequent vessel failure modes and melt characteristics upon the discharge are of paramount importance for plant safety assessment. The main purpose of the present study is to develop a method for reliable prediction of melt pool thermal hydraulics, namely to establish a computational platform for cost-effective, sufficiently-accurate numerical simulations and analyses of core Melt-Structure-Water Interactions in the LWR lower head during a postulated severe core-melting accident. To achieve the goal, an approach to efficient use of Computational Fluid Dynamics (CFD) has been proposed to guide and support the development of models suitable for accident analysis. The CFD method, on the one hand, is

  14. Effects of Nanofluid for In-Vessel Retention External Reactor Vessel Cooling on Critical Heat Flux using Pool Boiling Experiments

    International Nuclear Information System (INIS)

    Park, Sung Dae; Kang, Sarah; Lee, Seung Won; Bang, In Cheol

    2011-01-01

    In-vessel retention (IVR) is one of the severe accident management (SAM) strategies that are used in some nuclear power plants: AP600, AP1000, Loviisa and APR1400. One way of IVR is the method of external reactor vessel cooling (ERVC). When core melts and deposits on the bottom of reactor vessel, ERVC is starting to flood the reactor cavity to remove the decay heat through the wall of the reactor vessel. This process can improve the plant economics by reducing regulatory requirements. And increased safety margin leads to gain public acceptance. In this system, the heat removal is restricted by thermal limit called by critical heat flux (CHF). Besides, as advanced light water reactors such as South Korea's APR-1400, thermal safety margin is deceased. So, it is essential to get more safety margin. There are some approaches to enhance the ERVC: using the coating on the vessel outer surface, increasing the reactor cavity flood level, streamlining the gap between the vessel and the vessel insulation. Many investigations have been performed to evaluate the coolability of IVR In this paper, we firstly investigated the coating effects in the critical heat flux among the above mentioned approach methods. During the boiling phenomenon, a thin layer was formed on the heater surface in the nanofluid. This coating mechanism is well known theoretically. Nanofluids are colloidal dispersions of nanoparticles in traditional heat transfer fluids. One of the most interesting characteristics of nanofluids is their capability to enhance the critical heat flux (CHF) significantly. Nanofluid is made by typical particle materials. Materials of nanoparticles include metals (e.g., silver, copper, gold), metal oxides (e.g., titania, alumina, silica, zirconia), carbon allotrope (e.g., carbon nanotube, graphite). We selected the grapheneoxide nanofluid which is a kind of carbon allotrope. Graphene-oxide is attractive material with the high thermal conductivity and stable dispersion ability in

  15. Experimental Investigation on the Effect of Size and Pitch of Hydrophobic Square Patterns on the Pool Boiling Heat Transfer Performance of Cylindrical Copper Surface

    Directory of Open Access Journals (Sweden)

    Sujith Kumar C. S.

    2018-03-01

    Full Text Available In this work, pool boiling heat transfer tests were conducted for investigating the effects of the size and pitch of the hydrophobic square patterns on a copper test piece with the following dimensions: 40 mm long, 25 mm outer diameter, and 18 mm inner diameter. The size of the square patterns and the pitch were varied with an increment of 0.5 mm from 1 mm to 3 mm and from 4.5 to 5.5 mm, respectively. Among the various square patterns of different size and pitch, the 2 mm size square pattern with 5 mm pitch (inter-distance 3 mm was found to be the best because it gives the advantage of bubble coalescence behavior and also the rewetting phenomenon. The observed bubble departure diameter was 2.35 mm, and using this diameter, we predicted the maximum inter-distance between the patterns for producing inter coalescence of bubbles in the axial direction was 3.12 mm. Therefore, a side-by-side distance of 3 mm, which was closed to the estimated inter-distance graphically, can avoid the earlier inter coalescence of the bubbles between patterns on the surface in the axial direction. This results in better pool boiling heat transfer performance. Highlights: (1 Heterogeneous wettable structures were obtained on the copper surface using screen printing techniques; (2 The effect of the size and pitch of the hydrophobic patterns on the bubble dynamics was determined; (3 The wall superheats of all the heterogeneous wettable surfaces were less than the plain copper surface; (4 The highest heat transfer coefficient was obtained from the hydrophobic pattern with 2 mm size and 5 mm pitch.

  16. Modelling of Heat Transfer Phenomena for Vertical and Horizontal Configurations of In-Pool Condensers and Comparison with Experimental Findings

    Directory of Open Access Journals (Sweden)

    Davide Papini

    2010-01-01

    Different condenser tube arrangements have been developed for applications to the next generation NPPs. The two most used configurations, namely, horizontal and vertical tube condensers, are thoroughly investigated in this paper. Several thermal-hydraulic features were explored, being the analysis mainly devoted to the description of the best-estimate correlations and models for heat transfer coefficient prediction. In spite of a more critical behaviour concerning thermal expansion issues, vertical tube condensers offer remarkably better thermal-hydraulic performances. An experimental validation of the vertical tube correlations is provided by PERSEO facility (SIET labs, Piacenza, showing a fairly good agreement.

  17. Effect of the starting and turning performances on the subsequent swimming parameters of elite swimmers.

    Science.gov (United States)

    Veiga, Santiago; Roig, Andreu

    2017-03-01

    In the present research, we examined the effect of the starting and turning performances on the subsequent swimming parameters by (1) comparing the starting and turning velocities with the swimming parameters on the emersion and mid-pool segments and (2) by relating the individual behaviour of swimmers during the start and turns with subsequent behaviour on each swimming lap. One hundred and twelve 100 m performances on the FINA 2013 World Swimming Championships were analysed by an image-processing system (InThePool 2.0®). At the point of the start emersion, the swimming parameters of the 100-m elite swimmers were substantially greater than the mid-pool parameters, except on the breaststroke races. On the other hand, no diminution in the swimming parameters was observed between the turn emersion and the mid-pool swimming, except on the butterfly and backstroke male races. Changes on the surface swimming kinematics were not generally related to the starting or turning parameters, although male swimmers who develop faster starts seem to achieve faster velocities at emersion. Race analysts should be aware of a transfer of momentum when swimmers emerge from underwater with implications on the subsequent swimming kinematics, especially for male swimmers who employ underwater undulatory techniques.

  18. 76 FR 62605 - Virginia Graeme Baker Pool and Spa Safety Act; Interpretation of Unblockable Drain

    Science.gov (United States)

    2011-10-11

    ... 19, 2008. The VGB Act's purpose is to prevent suction entrapment by swimming pool and spa drains and child drowning in swimming pools and spas. Section 1404(c)(1)(A)(i) of the VGB Act requires that each... area (beyond the shadowed portion) cannot create a suction force in excess of the removal force values...

  19. Vernal Pools

    Data.gov (United States)

    California Department of Resources — This is a polygon layer representing existing vernal pool complexes in California's Central Valley, as identified and mapped by Dr. Robert F. Holland. The purpose of...

  20. Simulated front crawl swimming performance related to critical speed and critical power

    NARCIS (Netherlands)

    Toussaint, H.M.; Wakayoshi, K.; Hollander, A.P.; Ogita, F.

    1998-01-01

    Purpose: Competitive pool swimming events range in distance from 50 to 1500 m. Given the difference in performance times (±23-1000 s), the contribution of the aerobic and anaerobic energy systems changes considerably with race distance. In training practice the regression line between swimming

  1. A Guide to Swimming Instruction for Developmentally Disabled Children. Report Number 8168.

    Science.gov (United States)

    Noble, Susan

    The swimming instruction guide presents teaching techniques and skill progressions for developmentally disabled individuals and includes program development and administrative guidelines. Part 1 discusses swimming and developmentally disabled children, program planning and preparation elements (including pool, scheduling, staff, parents,…

  2. Safe Swimming (A Minute of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2017-06-01

    Most outbreaks linked to pools and water playgrounds are caused by Cryptosporidium. This podcast discusses ways to keep you healthy and safe while swimming.  Created: 6/1/2017 by MMWR.   Date Released: 6/1/2017.

  3. Independent Swimming for Children with Severe Physical Impairments.

    Science.gov (United States)

    Grosse, Susan J.; McGill, Christine D.

    1979-01-01

    Techniques are described for teaching severely physically disabled persons to swim. Approaches begin with a discussion of water adjustment progression and proceed through achieving breath control, mobility, developing movement in a supine position, and developing recovery. The conclusion addresses such final steps toward independence as pool entry…

  4. Predictors of Swimming Ability among Children and Adolescents in the United States

    Directory of Open Access Journals (Sweden)

    Jennifer Pharr

    2018-02-01

    Full Text Available Swimming is an important source of physical activity and a life skill to prevent drowning. However, little research has been conducted to understand predictors of swimming ability. The purpose of this study was to understand factors that predict swimming ability among children and adolescents in the United States (US. This was a cross-sectional survey conducted between February and April of 2017 across five geographically diverse cities. Participants were accessed through the Young Christian Men’s Association (YMCA and included parents of children aged 4–11 years old and adolescents aged 12–17 years old. Independent t-test, analysis of variance (ANOVA, and univariate and multivariate analyses were conducted. Several factors were significant (p ≤ 0.05 predictors of swimming ability and explained 53% of the variance in swimming ability. Variables that were positively associated with swimming ability included: ability of parent(s to swim, child/adolescent age, a best friend who enjoys swimming, water-safety knowledge, pool open all year, and encouragement to swim from parent(s. Variables that were negatively associated with swimming ability included: fear of drowning, being African American, and being female. Interventions and programs to improve the swimming ability of children and adolescents could be developed with these predictors in mind.

  5. Transitions between three swimming gaits in Paramecium escape.

    Science.gov (United States)

    Hamel, Amandine; Fisch, Cathy; Combettes, Laurent; Dupuis-Williams, Pascale; Baroud, Charles N

    2011-05-03

    Paramecium and other protists are able to swim at velocities reaching several times their body size per second by beating their cilia in an organized fashion. The cilia beat in an asymmetric stroke, which breaks the time reversal symmetry of small scale flows. Here we show that Paramecium uses three different swimming gaits to escape from an aggression, applied in the form of a focused laser heating. For a weak aggression, normal swimming is sufficient and produces a steady swimming velocity. As the heating amplitude is increased, a higher acceleration and faster swimming are achieved through synchronized beating of the cilia, which begin by producing oscillating swimming velocities and later give way to the usual gait. Finally, escape from a life-threatening aggression is achieved by a "jumping" gait, which does not rely on the cilia but is achieved through the explosive release of a group of trichocysts in the direction of the hot spot. Measurements through high-speed video explain the role of trichocysts in defending against aggressions while showing unexpected transitions in the swimming of microorganisms. These measurements also demonstrate that Paramecium optimizes its escape pattern by taking advantage of its inertia.

  6. [The effect of swimming on the nasal passages and on tube function in children].

    Science.gov (United States)

    Desterbeck, R A; Stoop, A; Franckx, H; Clement, P A; Kaufman, L; Rousseeuw, P

    1984-01-01

    In two studies the authors want to confirm experimentally what is assumed in every day ENT-practice: otitis and sinusitis are not infrequent complications of swimming. The first study, involving 60 children with chronic non-specific lung diseases shows that swimming in a sea water pool increases the nasal airway resistance during two days. In the second study, performed in 32 normal children swimming in a chlorous pool, a negative relationship is found between the number of days after the swimming and the increased nasal airway resistance. Probably other factors also play a part in this phenomenon. Due to the too small number of children showing an otitis media with effusion, the influence of swimming on the function of the Eustachian tube could not be determined.

  7. The pool chlorine hypothesis and asthma among boys.

    LENUS (Irish Health Repository)

    Cotter, A

    2012-01-31

    Swimming pool sanitation has largely been concerned with the microbiological quality of pool water, which is normally treated using a number of chlorine products. Recent studies have pointed to the potential hazards of chlorine by-products to the respiratory epithelium, particularly in indoor, poorly ventilated, pools. The aim of our study was to elucidate whether chronic exposure to indoor chlorinated swimming pools was associated with an increased likelihood of the development of asthma in boys. METHODS: The subjects were boys aged between 6 and 12 years. Data was collected by means of parental responses to a standardized asthma questionnaire (ISAAC: International Study of Asthma and Allergies in Childhood), supplemented with additional questions regarding frequency of attendance, number of years attendance, whether the child is a swimming team member. The questionnaire return rate was 71\\/% (n = 121). 23 boys were excluded on the basis that they had asthma before they started swimming (n = 97). There was a significant association between number of years a boy had been swimming and the likelihood of wheezing in the last 12 months (p = 0.009; OR = 1.351; 95% CI = 1.077-1.693) and diagnosed asthma (p = 0.046; OR = 1.299; 95% CI = 1.004-1.506). The greater the number the number of years a boy had been attending an indoor, chlorinated pool, the greater the likelihood of wheezing in the last 12 months or "had asthma". Age, parental smoking habits and being a swimming team member had no association with any of the asthma variables examined. Swimming pool attendance may be a risk factor in asthma in boys.

  8. Fuel assembly storage pool

    International Nuclear Information System (INIS)

    Hiranuma, Hiroshi.

    1976-01-01

    Object: To remove limitation of the number of storage of fuel assemblies to increase the number of storage thereof so as to relatively reduce the water depth required for shielding radioactive rays. Structure: Fuel assembly storage rack containers for receiving a plurality of spent fuel assembly racks are stacked in multi-layer fashion within a storage pool filled with water for shielding radioactive rays and removing heat. (Furukawa, Y.)

  9. 2007 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  10. 2006 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  11. 2009 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  12. 2008 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  13. 2010 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  14. 2012 Swimming Season Fact Sheets

    Science.gov (United States)

    To help beachgoers make informed decisions about swimming at U.S. beaches, EPA annually publishes state-by-state data about beach closings and advisories for the previous year's swimming season. These fact sheets summarize that information by state.

  15. Front crawl swimming analysis using accelerometers

    DEFF Research Database (Denmark)

    Espinosa, Hugo G; Nordsborg, Nikolai Baastrup; Thiel, David V

    2015-01-01

    Biomechanical characteristics such as stroke rate and stroke length can be used to determine the velocity of a swimmer and can be analysed in both a swimming pool and a flume. The aim of the present preliminary study was to investigate the differences between the acceleration data collected from ...... movements (0.64 ≤ r ≤ 0.75). The correlation coefficients are (0.75 ≤ r ≤ 0.83) and (0.82 ≤ r ≤ 0.89) for the other two axes....

  16. Pool scrubbing

    International Nuclear Information System (INIS)

    Lopez-Jimenez, J.; Herranz, J.; Escudero, M.J.; Espigares, M.M.; Peyres, V.; Polo, J.; Kortz, Ch.; Koch, M.K.; Brockmeier, U.; Unger, H.; Dutton, L.M.C.; Smedley, Ch.; Trow, W.; Jones, A.V.; Bonanni, E.; Calvo, M.; Alonso, A.

    1996-12-01

    The Source Term Project in the Third Frame Work Programme of the European Union Was conducted under and important joined effort on pool scrubbing research. CIEMAT was the Task Manager of the project and several other organizations participated in it: JRC-Ispra, NNC Limited, RUB-NES and UPM. The project was divided into several tasks. A peer review of the models in the pool scrubbing codes SPARC90 and BUSCA-AUG92 was made, considering the different aspects in the hydrodynamic phenomenology, particle retention and fission product vapor abortions. Several dominant risk accident sequences were analyzed with MAAP, SPARC90 and BUSCA-AUG92 codes, and the predictions were compared. A churn-turbulent model was developed for the hydrodynamic behaviour of the pool. Finally, an experimental programme in the PECA facility of CIEMAT was conducted in order to study the decontamination factor under jet injection regime, and the experimental observations were compared with the SPARC and BUSCA codes. (Author)

  17. In the making: SA-PIV applied to swimming practice

    Science.gov (United States)

    van Houwelingen, Josje; van de Water, Willem; Kunnen, Rudie; van Heijst, Gertjan; Clercx, Herman

    2017-11-01

    To understand and optimize the propulsion in human swimming, a deep understanding of the hydrodynamics of swimming is required. This is usually based on experiments and numerical simulations under laboratory conditions.. In this study, we bring basic fluid mechanics knowledge and experimental measurement techniques to analyze the flow towards the swimming practice itself. A flow visualization setup is build and placed in a regular swimming pool. The measurement volume contains five homogeneous air bubble curtains illuminated by ambient light. The bubbles in these curtains act as tracer particles. The bubble motion is captured by six cameras placed in the side wall of the pool. It is intended to apply SA-PIV (synthetic aperture PIV) for analyzing the flow structures on multiple planes in the measurement volume. The system has been calibrated and the calibration data are used to refocus on the planes of interest. Multiple preprocessing steps need to be executed to obtain the proper quality of images before applying PIV. With a specially programmed video card to process and analyze the images in real-time feedback about swimming performance will become possible. We report on the first experimental data obtained by this system.

  18. Swimming attendance during childhood and development of asthma: Meta-analysis.

    Science.gov (United States)

    Valeriani, Federica; Protano, Carmela; Vitali, Matteo; Romano Spica, Vincenzo

    2017-05-01

    The association between asthma and swimming pool attendance has not been demonstrated and currently there are conflicting results. In order to clarify the association between asthma diagnosis in children and swimming pool attendance, and to assess the consistency of the available epidemiological studies, we completed a literature analysis on the relationship between the exposure to disinfection by-products in indoor swimming pools during childhood and asthma diagnosis. Following the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) criteria, a systematic review and meta-analysis was performed by searching MEDLINE via PubMed, TOXNET, and Scopus databases (from inception to 20 April 2015) using the key word "Asthma" together with "swimming pool", "disinfection by-products", "indoor air pollution" and "children". Inclusion criteria were: English language, a complete analytic study design involving a cohort of children (0-16 years), a well-defined definition of exposure, and the presence of data on effect and variance. Studies on in vivo, in vitro or professional and accidental exposure were excluded. After a screening process, seven reports (n = 5851 subjects) were included out of a total of 2928 references. The reported OR of the association between swimming pool attendance and asthma prevalence ranged from 0.58 to 2.30. The present meta-analysis failed to identify a significant difference in asthma development between children attending swimming pools and controls (OR, 1.084; 95% CI: 0.89-1.31). Swimming in childhood does not increase the likelihood of doctor-diagnosed asthma. Based on this meta-analysis review, the association of the disease with indoor pool attendance is still unclear. © 2016 Japan Pediatric Society.

  19. Swimming performance assessment in fishes.

    Science.gov (United States)

    Tierney, Keith B

    2011-05-20

    Swimming performance tests of fish have been integral to studies of muscle energetics, swimming mechanics, gas exchange, cardiac physiology, disease, pollution, hypoxia and temperature. This paper describes a flexible protocol to assess fish swimming performance using equipment in which water velocity can be controlled. The protocol involves one to several stepped increases in flow speed that are intended to cause fish to fatigue. Step speeds and their duration can be set to capture swimming abilities of different physiological and ecological relevance. Most frequently step size is set to determine critical swimming velocity (U(crit;)), which is intended to capture maximum sustained swimming ability. Traditionally this test has consisted of approximately ten steps each of 20 min duration. However, steps of shorter duration (e.g. 1 min) are increasingly being utilized to capture acceleration ability or burst swimming performance. Regardless of step size, swimming tests can be repeated over time to gauge individual variation and recovery ability. Endpoints related to swimming such as measures of metabolic rate, fin use, ventilation rate, and of behavior, such as the distance between schooling fish, are often included before, during and after swimming tests. Given the diversity of fish species, the number of unexplored research questions, and the importance of many species to global ecology and economic health, studies of fish swimming performance will remain popular and invaluable for the foreseeable future.

  20. Keila Tervisekeskus. Ujula = Keila Health Club. Swimming Pool / Ain Padrik

    Index Scriptorium Estoniae

    Padrik, Ain, 1947-

    2001-01-01

    Projekteerija: Arhitektuuribüroo Künnapu & Padrik. Arhitektid Ain Padrik ja Kristi Alamaa, sisearhitekt Sirje Männik. Konstruktsioonid: Jaan Laks, A-Grupp. Ujulas on võistlus- ja lastebassein, suvel on avatud välibassein. 5 ill.: I korruse plaan, ristlõige, vaated

  1. Model of large pool fires

    International Nuclear Information System (INIS)

    Fay, J.A.

    2006-01-01

    A two zone entrainment model of pool fires is proposed to depict the fluid flow and flame properties of the fire. Consisting of combustion and plume zones, it provides a consistent scheme for developing non-dimensional scaling parameters for correlating and extrapolating pool fire visible flame length, flame tilt, surface emissive power, and fuel evaporation rate. The model is extended to include grey gas thermal radiation from soot particles in the flame zone, accounting for emission and absorption in both optically thin and thick regions. A model of convective heat transfer from the combustion zone to the liquid fuel pool, and from a water substrate to cryogenic fuel pools spreading on water, provides evaporation rates for both adiabatic and non-adiabatic fires. The model is tested against field measurements of large scale pool fires, principally of LNG, and is generally in agreement with experimental values of all variables

  2. London 2012 Paralympic swimming: passive drag and the classification system.

    Science.gov (United States)

    Oh, Yim-Taek; Burkett, Brendan; Osborough, Conor; Formosa, Danielle; Payton, Carl

    2013-09-01

    The key difference between the Olympic and Paralympic Games is the use of classification systems within Paralympic sports to provide a fair competition for athletes with a range of physical disabilities. In 2009, the International Paralympic Committee mandated the development of new, evidence-based classification systems. This study aims to assess objectively the swimming classification system by determining the relationship between passive drag and level of swimming-specific impairment, as defined by the current swimming class. Data were collected on participants at the London 2012 Paralympic Games. The passive drag force of 113 swimmers (classes 3-14) was measured using an electro-mechanical towing device and load cell. Swimmers were towed on the surface of a swimming pool at 1.5 m/s while holding their most streamlined position. Passive drag ranged from 24.9 to 82.8 N; the normalised drag (drag/mass) ranged from 0.45 to 1.86 N/kg. Significant negative associations were found between drag and the swimming class (τ = -0.41, p < 0.01) and normalised drag and the swimming class (τ = -0.60, p < 0.01). The mean difference in drag between adjacent classes was inconsistent, ranging from 0 N (6 vs 7) to 11.9 N (5 vs 6). Reciprocal Ponderal Index (a measure of slenderness) correlated moderately with normalised drag (r(P) = -0.40, p < 0.01). Although swimmers with the lowest swimming class experienced the highest passive drag and vice versa, the inconsistent difference in mean passive drag between adjacent classes indicates that the current classification system does not always differentiate clearly between swimming groups.

  3. Improving Pool Fencing Legislation in Queensland, Australia: Attitudes and Impact on Child Drowning Fatalities

    Directory of Open Access Journals (Sweden)

    Richard C. Franklin

    2017-11-01

    Full Text Available Four-sided, non-climbable pool fencing is an effective strategy for preventing children from drowning in home swimming pools. In 2009, the Queensland Government introduced legislation to improve the effectiveness of pool fencing. This study explores community attitudes towards the effectiveness of these legislative changes and examines child (<5 years drowning deaths in pools. Data from the 2011 Queensland Computer-Assisted Telephone Interviewing (CATI Social Survey include results from questions related to pool ownership and pool fencing legislation. Fatal child drowning cases between 1 January 2005 and 31 December 2015 were sourced from coronial data. Of the 1263 respondents, 26/100 households had a pool. A total of 58% believed tightening legislation would be effective in reducing child drowning deaths. Pool owners were more likely to doubt the effectiveness of legislation (p < 0.001 when compared to non-pool owners. Perceptions of effectiveness did not differ by presence of children under the age of five. There were 46 children who drowned in Queensland home pools (7.8/100,000 pools with children residing in the residence/annum between 2005 and 2015. While pool owners were less likely to think that tightening the legislation would be effective, the number of children drowning in home swimming pools declined over the study period. Drowning prevention agencies have more work to do to ensure that the most vulnerable (young children in houses with swimming pools are protected.

  4. Stirring by swimming bodies

    Energy Technology Data Exchange (ETDEWEB)

    Thiffeault, Jean-Luc, E-mail: jeanluc@math.wisc.ed [Department of Mathematics, University of Wisconsin - Madison, 480 Lincoln Dr., Madison, WI 53706 (United States); Institute for Mathematics and Applications, University of Minnesota - Twin Cities, 207 Church Street S.E., Minneapolis, MN 55455 (United States); Childress, Stephen [Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, NY 10012 (United States)

    2010-07-26

    We consider the stirring of an inviscid fluid caused by the locomotion of bodies through it. The swimmers are approximated by non-interacting cylinders or spheres moving steadily along straight lines. We find the displacement of fluid particles caused by the nearby passage of a swimmer as a function of an impact parameter. We use this to compute the effective diffusion coefficient from the random walk of a fluid particle under the influence of a distribution of swimming bodies. We compare with the results of simulations. For typical sizes, densities and swimming velocities of schools of krill, the effective diffusivity in this model is five times the thermal diffusivity. However, we estimate that viscosity increases this value by two orders of magnitude.

  5. Investigación de un brote respiratorio agudo por exposición a cloro gas en una piscina pública Investigation of an outbreak of acute respiratory illness due to exposure to chlorine gas in a public swimming pool

    Directory of Open Access Journals (Sweden)

    Diego Almagro Nievas

    2008-06-01

    Full Text Available Se diseñó un estudio de casos y controles para investigar el accidente químico ocurrido en una piscina pública en el verano de 2005 y describir los factores ambientales responsables, analizar el efecto del cloro gas y valorar la evolución clínica y funcional del aparato respiratorio. Las intervenciones fueron las siguientes: inspecciones ambientales, encuesta epidemiológica (variables sociodemográficas, ubicación en el momento del accidente, olor percibido y seguimiento clínico y espirométrico de la función respiratoria. Se encuestaron 65 casos y 48 controles. El suceso se produjo al mezclar accidentalmente ácido clorhídrico e hipoclorito sódico, lo que generó cloro gas. Los síntomas predominantes fueron tos y disnea. El riesgo de enfermar en niños era 10 veces mayor si tenían una enfermedad respiratoria previa y 4 veces superior si estaban a una distancia inferior a 40 m del lugar del accidente. Todos los casos evolucionaron hacia la curación, excepto uno que tenía antecedentes asmáticos.A case-control study was designed to investigate a chemical accident that occurred in a swimming-pool in the summer of 2005. The aim was to describe the environmental factors involved in the accident, to assess the effect of chlorine gas on the respiratory system, and to perform a clinical and spirometric follow-up. The following interventions were carried out: environmental inspection, epidemiologic survey (including sociodemographic variables, location at the time of the accident, perception of an abnormal smell, and clinical and spirometric outcomes to assess respiratory function. Sixty-five cases and 48 controls were identified and interviewed. The accident was produced by accidental admixture of hydrochloric acid with sodium hypochlorite resulting in chlorine gas release. The main clinical symptoms were dyspnea and cough. The risk of becoming ill was 10-fold higher in children with a previous lung disease and was 4-fold higher when

  6. Determination of the solids retainment effectiveness of disposable swim diapers.

    Science.gov (United States)

    Maas, Richard P; Patch, Steven C; Berkowitz, Jacob F; Johnson, Holly D

    2004-06-01

    In light of recent and increasing incidences of pathogenic E. coli outbreaks at public bathing facilities attributable to non-toilet-trained infants and toddlers, many such facilities are restricting water contact for this age group. A number of manufacturers are now offering disposable "swim diapers," which claim to effectively retain fecal material under typical pool play conditions. The study reported here examined the solids retention effectiveness of three major brands of swim diapers as well as of conventional disposable diapers, under simulated water play conditions. Swim diapers of all three brands exhibited an approximately equal fine-solids retention capability of about 98 to 99 percent over 30 minutes of water immersion activity. Conventional disposable diapers invariably fell down or came apart during the experiments, resulting in very limited solids retention. This study indicates that commercially available swim diapers represent a vast improvement in reducing the potential for fecal material release in public pool facilities, but that some release will still generally occur with these products.

  7. Hospital hydrotherapy pools treated with ultra violet light: bad bacteriological quality and presence of thermophilic Naegleria.

    OpenAIRE

    De Jonckheere, J. F.

    1982-01-01

    The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management. On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was pr...

  8. Radio-transmitted electromyogram signals as indicators of swimming speed in lake trout and brown trout

    DEFF Research Database (Denmark)

    Thorstad, E.B.; Økland, F.; Koed, Anders

    2000-01-01

    Swimming speed and average electromyogram (EMG) pulse intervals were highly correlated in individual lake trout Salvelinus namaycush (r(2)=0.52-0.89) and brown trout Salmo trutta (r(2)=0.45-0.96). High correlations were found also for pooled data in both lake trout (r(2)=0.90) and brown trout...... of the Ema stock (r(2)=0.96) and Laerdal stock (r(2)=0.96). The linear relationship between swimming speed and average EMG pulse intervals differed significantly among lake trout and the brown trout stocks. This successful calibration of EMGs to swimming speed opens the possibility of recording swimming...... speed of free swimming lake trout and brown trout in situ. EMGs can also be calibrated to oxygen consumption to record energy expenditure. (C) 2000 The Fisheries Society of the British Isles...

  9. Sand swimming lizard: sandfish

    OpenAIRE

    Maladen, Ryan D.; Ding, Yang; Kamor, Adam; Goldman, Daniel I.

    2009-01-01

    We use high-speed x-ray imaging to reveal how a small (~10cm) desert dwelling lizard, the sandfish (Scincus scincus), swims within a granular medium [1]. On the surface, the lizard uses a standard diagonal gait, but once below the surface, the organism no longer uses limbs for propulsion. Instead it propagates a large amplitude single period sinusoidal traveling wave down its body and tail to propel itself at speeds up to ~1.5 body-length/sec. Motivated by these experiments we study a numeric...

  10. Planning, implementation, and history of the first 5 years of operation of the Craig, Alaska, pool and school biomass heating system—a case study

    Science.gov (United States)

    Allen M. Brackley; K. Petersen

    2016-01-01

    A wood-based energy project in Craig, Alaska, to heat the community's aquatic center and two of its schools was the first such installation in Alaska to convert from fossil fuels to a renewable energy source. Initial interest in the project started in 2004. The system came online in April 2008. This report provides an overview of the new heating system's...

  11. Influence of mobile games on the process of teaching of students that can not swim

    Directory of Open Access Journals (Sweden)

    Strelnykov G.L.

    2012-02-01

    Full Text Available Considered direction in teaching of students to swimming in terms 25 meter pool. 30 students took part in an experiment. The place of mobile games in the process of teaching of novices is certain. Information of results of testing of level of physical preparedness of students is presented. Positive influence of mobile games on the process of mastering of skills of swimming and co-operations on water is marked. Forms and methods of mastering of skills and conduct in water are offered. The motive mode and forms of organization of educational process of not able to swim students is recommended.

  12. Hawaii ESI: POOLS (Anchialine Pool Points)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sensitive biological resource data for anchialine pools in Hawaii. Anchialine pools are small, relatively shallow coastal ponds that occur...

  13. The Impact of Baby Swimming on Introductory and Elementary Swimming Training

    OpenAIRE

    Břízová, Gabriela

    2007-01-01

    THESIS ANNOTATION Title: The Impact of Baby Swimming on Introductory and Elementary Swimming Training Aim: To assess the impact of 'baby swimming' on the successfulness in introductory and partly in elementary swimming training, and to find out whether also other circumstances (for example the length of attendance at 'baby swimming') have some influence on introductory swimming training. Methods: We used a questionnaire method for the parents of children who had attended 'baby swimming' and f...

  14. Baby swimming and respiratory health.

    Science.gov (United States)

    Nystad, Wenche; Håberg, Siri E; London, Stephanie J; Nafstad, Per; Magnus, Per

    2008-05-01

    To estimate the effect of baby swimming in the first 6 months of life on respiratory diseases from 6 to 18 months. We used data from The Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health in children born between 1999 and 2005 followed from birth to the age of 18 months (n = 30,870). Health outcomes: lower respiratory tract infections (LRTI), wheeze and otitis media between 6 and 18 months of age. baby swimming at the age of 6 months. The effect of baby swimming was estimated by logistic regression analysis adjusting for potential confounders. About 25% of the children participated in baby swimming. The prevalence of LRTI was 13.3%, wheeze 40.0% and otitis media 30.4%. Children who were baby swimming were not more likely to have LRTI, to wheeze or to have otitis media. However, children with atopic mothers who attended baby swimming had an increased risk of wheeze, adjusted odds ratios (aOR) 1.24 (95% CI 1.11, 1.39), but not LRTI or otitis media. This was also the case for children without respiratory diseases before 6 months aOR 1.08 (95%CI 1.02-1.15). Baby swimming may be related to later wheeze. However, these findings warrant further investigation.

  15. Disposable swim diaper retention of Cryptosporidium-sized particles on human subjects in a recreational water setting.

    Science.gov (United States)

    Amburgey, James E; Anderson, J Brian

    2011-12-01

    Cryptosporidium is a chlorine-resistant protozoan parasite responsible for the majority of waterborne disease outbreaks in recreational water venues in the USA. Swim diapers are commonly used by diaper-aged children participating in aquatic activities. This research was intended to evaluate disposable swim diapers for retaining 5-μm diameter polystyrene microspheres, which were used as non-infectious surrogates for Cryptosporidium oocysts. A hot tub recirculating water without a filter was used for this research. The microsphere concentration in the water was monitored at regular intervals following introduction of microspheres inside of a swim diaper while a human subject undertook normal swim/play activities. Microsphere concentrations in the bulk water showed that the majority (50-97%) of Cryptosporidium-sized particles were released from the swim diaper within 1 to 5 min regardless of the swim diaper type or configuration. After only 10 min of play, 77-100% of the microspheres had been released from all swim diapers tested. This research suggests that the swim diapers commonly used by diaper-aged children in swimming pools and other aquatic activities are of limited value in retaining Cryptosporidium-sized particles. Improved swim diaper solutions are necessary to efficiently retain pathogens and effectively safeguard public health in recreational water venues.

  16. [Management of infectious risk associated with therapeutic pools].

    Science.gov (United States)

    Chapuis, C; Gardes, S; Tasseau, F

    2004-06-01

    There is no specific legislation concerning pools and others medical hydrotherapy equipments relating hygiene and security rules. For this reason, the hydrotherapy pools use the public swimming pools legislation. This article is based on literature review (database Medline and Embase--manual research). This article offers a review of pool associated infections along with the description of the measures designed to minimise the possible transmission of infection during hydrotherapy activities such as: Technical measures: pool and premises conception, water treatments, feed tanks, air quality. Hygiene rules for patients and hospital staff and pathologies which are contra-indications to hydrotherapy activities. Microbiological and physico-chemical monitoring. The infectious risk remains low with therapeutic pools. However, the development of specific legislation and surveillance should be enhanced. All these measures are part of the quality assurance program that must be implemented to control the safety of these installations.

  17. Examining self-training procedures in leisure swimming.

    Science.gov (United States)

    J Potdevin, Francois; Normani, Clement; Pelayo, Patrick

    2013-01-01

    their session even if they have a good skill level. This suggests to improve health strategy education and swimming pool environment.

  18. Swimming Performance and Metabolism of Golden Shiners

    Science.gov (United States)

    The swimming ability and metabolism of golden shiners, Notemigonus crysoleucas, was examined using swim tunnel respirometery. The oxygen consumption and tail beat frequencies at various swimming speeds, an estimation of the standard metabolic rate, and the critical swimming speed (Ucrit) was determ...

  19. Swimming ability and physiological response to swimming fatigue in ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-04-06

    Apr 6, 2009 ... The swimming endurance of kuruma shrimp, Marsupenaeus japonicus (11.04 ± 2.43 g) at five swimming speeds (23.0, 26.7, 31.0, 34.6 and 38.6 cm s-1) was determined in a circulating flume at 25.7 ± 0.7°C. The plasma glucose and total protein, hepatopancreas and pleopods muscle glycogen ...

  20. Swimming ability and physiological response to swimming fatigue in ...

    African Journals Online (AJOL)

    The swimming endurance of kuruma shrimp, Marsupenaeus japonicus (11.04 ± 2.43 g) at five swimming speeds (23.0, 26.7, 31.0, 34.6 and 38.6 cm s-1) was determined in a circulating flume at 25.7 ± 0.7°C. The plasma glucose and total protein, hepatopancreas and pleopods muscle glycogen concentrations were ...

  1. Heat

    CERN Document Server

    Lawrence, Ellen

    2016-01-01

    Is it possible to make heat by rubbing your hands together? Why does an ice cube melt when you hold it? In this title, students will conduct experiments to help them understand what heat is. Kids will also investigate concepts such as which materials are good at conducting heat and which are the best insulators. Using everyday items that can easily be found around the house, students will transform into scientists as they carry out step-by-step experiments to answer interesting questions. Along the way, children will pick up important scientific skills. Heat includes seven experiments with detailed, age-appropriate instructions, surprising facts and background information, a "conclusions" section to pull all the concepts in the book together, and a glossary of science words. Colorful, dynamic designs and images truly put the FUN into FUN-damental Experiments.

  2. Healthy Swimming/Recreational Water

    Science.gov (United States)

    ... Model Aquatic Health Code (MAHC) Featured Partners Healthy Water Sites Healthy Water Drinking Water Healthy Swimming Global WASH Other Uses of Water WASH-related Emergencies & Outbreaks Water, Sanitation, & Environmentally-related ...

  3. Free Swimming in Ground Effect

    Science.gov (United States)

    Cochran-Carney, Jackson; Wagenhoffer, Nathan; Zeyghami, Samane; Moored, Keith

    2017-11-01

    A free-swimming potential flow analysis of unsteady ground effect is conducted for two-dimensional airfoils via a method of images. The foils undergo a pure pitching motion about their leading edge, and the positions of the body in the streamwise and cross-stream directions are determined by the equations of motion of the body. It is shown that the unconstrained swimmer is attracted to a time-averaged position that is mediated by the flow interaction with the ground. The robustness of this fluid-mediated equilibrium position is probed by varying the non-dimensional mass, initial conditions and kinematic parameters of motion. Comparisons to the foil's fixed-motion counterpart are also made to pinpoint the effect that free swimming near the ground has on wake structures and the fluid-mediated forces over time. Optimal swimming regimes for near-boundary swimming are determined by examining asymmetric motions.

  4. System Wide Information Management (SWIM)

    Science.gov (United States)

    Hritz, Mike; McGowan, Shirley; Ramos, Cal

    2004-01-01

    This viewgraph presentation lists questions regarding the implementation of System Wide Information Management (SWIM). Some of the questions concern policy issues and strategies, technology issues and strategies, or transition issues and strategies.

  5. Swimming literacy field hockey woman player ground.

    OpenAIRE

    Baštová, Miroslava

    2012-01-01

    Title: Swimming literacy field hockey woman player ground. Objectives: To obtain and analyze data on the level ground swimming literacy field hockey woman player. Their perception swimming literacy for life, the use of non-specific regeneration and as a training resource. Methods: Analysis of scientific literature, survey, case study, data analysis and graphical presentation of results. Results of the work: field hockey player as swimming literate, benefits swimming but not used as a means of...

  6. Heat transfer in pool boiling liquid neon, deuterium and hydrogen, and critical heat flux in forced convection of liquid neon; Echanges thermiques superficiels dans le neon, le deuterium et l'hydrogene liquides bouillants en convection libre et flux de chaleur critiques en convection forcee du neon liquide

    Energy Technology Data Exchange (ETDEWEB)

    Astruc, J.M. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-12-01

    In the first part, free-convection and nucleate pool boiling heat transfer (up to burn-out heat flux) between a platinum wire of 0.15 mm in diameter in neon, deuterium and hydrogen has been studied at atmospheric pressure. These measurements were continued in liquid neon up to 23 bars (Pc {approx_equal} 26.8 b). Film boiling heat transfer coefficients have been measured in pool boiling liquid neon at atmospheric pressure with three heating wires (diameters 0.2, 0.5, 2 mm). All the results have been compared with existing correlations. The second part is devoted to measurements of the critical heat flux limiting heat transfer with small temperature differences between the wall and the liquid neon flowing inside a tube (diameters 3 x 3.5 mm) heated by joule effect on 30 cm of length. Influences of flow stability, nature of electrical current, pressure, mass flow rate and subcooling are shown. In conclusion, the similarity of the heat transfer characteristics in pool boiling as well as in forced convection of liquid neon and hydrogen is emphasized. (author) [French] Dans la premiere partie, on a etudie les echanges thermiques en regime de convection libre et d'ebullition nucleee (jusqu'au flux critique de l'ebullition nucleee) entre un fil de platine (diametre 0,15 mm) chauffe electriquement et un bain de liquide (neon, deuterium, ou hydrogene) bouillant a la pression atmospherique. On a poursuivi ces mesures dans le neon jusqu'a une pression de 23 bars (Pc {approx_equal} 26,8 b). On a mesure en outre les coefficients d'echanges thermiques en regime de calefaction dans le neon liquide a pression atmospherique. Tous ces resultats sont compares a diverses correlations existantes. La deuxieme partie est axee sur la mesure des flux de chaleur critiques limitant les echanges thermiques avec faible ecart de temperatures entre la paroi et le neon liquide s'ecoulant dans un tube (diam. 3 x 3,5 mm) chauffe par effet joule sur 30 cm de longueur. On

  7. Swimming with the Shoal

    Science.gov (United States)

    Childs, Ann

    2017-10-01

    This article responds to Yuli Rahmawati and Peter Charles Taylor's piece and explores my role as a science teacher, science teacher educator and researcher in two contexts, Sierra Leone and Bhutan. In the first part of the article I reflect on my 3 years as a science teacher in Sierra Leone and demonstrate resonances with Yuli's accounts of culture shock and with her positioning of herself in a third space. I also reflect on the importance of colleagues in helping me reshape my identity as a science teacher in this new context. The second part of the article reflects on much shorter periods of time in Bhutan and my work as a teacher educator and researcher where, unlike Sierra Leone, it was not possible because of the short periods I worked there, to occupy a third space. I close by discussing how in Bhutan, but also Sierra Leone, collaboration with colleagues allowed me to contribute my own expertise, despite my lack of a deep understanding of the cultural context, in a way that was as valuable as possible. I liken this way of collaborative working in my professional life as `swimming with the shoal'.

  8. Is paramecium swimming autonomic?

    Science.gov (United States)

    Bandyopadhyay, Promode R.; Toplosky, Norman; Hansen, Joshua

    2010-11-01

    We seek to explore if the swimming of paramecium has an underlying autonomic mechanism. Such robotic elements may be useful in capturing the disturbance field in an environment in real time. Experimental evidence is emerging that motion control neurons of other animals may be present in paramecium as well. The limit cycle determined using analog simulation of the coupled nonlinear oscillators of olivo-cerebellar dynamics (ieee joe 33, 563-578, 2008) agrees with the tracks of the cilium of a biological paramecium. A 4-motor apparatus has been built that reproduces the kinematics of the cilium motion. The motion of the biological cilium has been analyzed and compared with the results of the finite element modeling of forces on a cilium. The modeling equates applied torque at the base of the cilium with drag, the cilium stiffness being phase dependent. A low friction pendulum apparatus with a multiplicity of electromagnetic actuators is being built for verifying the maps of the attractor basin computed using the olivo-cerebellar dynamics for different initial conditions. Sponsored by ONR 33.

  9. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 1, Methodology

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    The Energy Policy and Conservation Act (P.L. 94-163), as amended, establishes energy conservation standards for 12 of the 13 types of consumer products specifically covered by the Act. The legislation requires the Department of Energy (DOE) to consider new or amended standards for these and other types of products at specified times. DOE is currently considering amending standards for seven types of products: water heaters, direct heating equipment, mobile home furnaces, pool heaters, room air conditioners, kitchen ranges and ovens (including microwave ovens), and fluorescent light ballasts and is considering establishing standards for television sets. This Technical Support Document presents the methodology, data, and results from the analysis of the energy and economic impacts of the proposed standards. This volume presents a general description of the analytic approach, including the structure of the major models.

  10. Influence of pre-school swimming on level of swimming abilities of early schol age children

    OpenAIRE

    Velová, Lenka

    2011-01-01

    My thesis paper is focused on children swimming from their birth to early school age. The pivotal part of the paper is the comparison of swimming abilities between primary school children who have passed pre-school swimming training and those who have had no training at all. Theoretical framework of the paper is then focused on general swimming theory, characteristics of children's evolutionary stages within the context of swimming and definition of basic swimming skills.

  11. Swimming Safely (A Cup of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2014-05-22

    In the summertime, families will be flocking to pools for relaxation and relief from the heat. A few simple precautions can help ensure a safe day in the water. In this podcast, Michele Hlavsa discusses ways to stay safe at the pool.  Created: 5/22/2014 by MMWR.   Date Released: 5/22/2014.

  12. Socioeconomic environment, availability of sports facilities, and jogging, swimming and gym use.

    Science.gov (United States)

    Pascual, Cruz; Regidor, Enrique; Martínez, David; Elisa Calle, M; Domínguez, Vicente

    2009-06-01

    The aim of the study was to evaluate the association of the availability of sports facilities and socioeconomic environment with jogging, swimming and gym use in Spain. The indicators of availability of sports facilities were the number of swimming pools and the number of gyms per 10,000 population. The indicators of socioeconomic environment were average provincial income and provincial unemployment rate. The number of sports facilities was not related with either swimming or gym use and the indicators of socioeconomic environment were not associated with swimming in either sex, or with gym use in men. The findings of this study do not support the hypotheses proposed in previous investigations to explain the consistent relation between socioeconomic environment and lack of physical activity.

  13. EFFICIENCY OF DIFFERENT METHODOLOGICAL MODELS OF SWIMMING PRACTICE WITH PRE-SCHOOL CHILDREN

    Directory of Open Access Journals (Sweden)

    Dragan Krivokapić

    2006-06-01

    Full Text Available On the sample of 68 preschool boys and girls aged five to six years two models of swimming teaching realised with purpose to research their efficacity. lt was finded before that they were nonswimers. Testers deviated in two similar groups by basic motor and cognitive abilities. First model of swim teaching, signed as time deviated learning, was realised at the cloused swimming pool with 36 testers which exercised twice of week during three months. Second model of swim teaching, signed as time concentrated learning, was realised as a two-week course with 32 testers which exercised at the sea side. Two control assessment of swimming level knowledge were made during experimental process, and a final assesment was made at the and of the experiment Scaling tehnicque was used for assesing. An analysis of the obtained data resulted in the following conclusions: the both models of swim teaching were efficacity and majority of children accepted swim knovvledge. Results of time concentrated model learning were statistical significance beter then time deviated learning only in the control assesments, but the svviming level knowledge was not different in the final assment. That conclusion shows that model of time concentrated learning has more efficacity in the begining, and model of time deviated learning in the later period of teaching

  14. Using heat as a tracer to estimate spatially distributed mean residence times in the hyporheic zone of a riffle-pool sequence

    Science.gov (United States)

    Naranjo, Ramon C.

    2013-01-01

    Biochemical reactions that occur in the hyporheic zone are highly dependent on the time solutes that are in contact with sediments of the riverbed. In this investigation, we developed a 2-D longitudinal flow and solute-transport model to estimate the spatial distribution of mean residence time in the hyporheic zone. The flow model was calibrated using observations of temperature and pressure, and the mean residence times were simulated using the age-mass approach for steady-state flow conditions. The approach used in this investigation includes the mixing of different ages and flow paths of water through advection and dispersion. Uncertainty of flow and transport parameters was evaluated using standard Monte Carlo and the generalized likelihood uncertainty estimation method. Results of parameter estimation support the presence of a low-permeable zone in the riffle area that induced horizontal flow at a shallow depth within the riffle area. This establishes shallow and localized flow paths and limits deep vertical exchange. For the optimal model, mean residence times were found to be relatively long (9–40.0 days). The uncertainty of hydraulic conductivity resulted in a mean interquartile range (IQR) of 13 days across all piezometers and was reduced by 24% with the inclusion of temperature and pressure observations. To a lesser extent, uncertainty in streambed porosity and dispersivity resulted in a mean IQR of 2.2 and 4.7 days, respectively. Alternative conceptual models demonstrate the importance of accounting for the spatial distribution of hydraulic conductivity in simulating mean residence times in a riffle-pool sequence.

  15. Variability in Measurement of Swimming Forces: A Meta-Analysis of Passive and Active Drag

    Science.gov (United States)

    Havriluk, Rod

    2007-01-01

    An analysis was conducted to identify sources of true and error variance in measuring swimming drag force to draw valid conclusions about performance factor effects. Passive drag studies were grouped according to methodological differences: tow line in pool, tow line in flume, and carriage in tow tank. Active drag studies were grouped according to…

  16. THE EFFECTS OF DIFFERENT MODELS OF SWIMMING TRAINING (DEFINED IN RELATION TO ANAEROBIC THRESHOLD ON THE INCREASE OF SWIM SPEED

    Directory of Open Access Journals (Sweden)

    Dragan Krivokapić

    2007-05-01

    Full Text Available On the sample of 32 fourth grade students of some Belgrade highs schools, who had the physical education classes carried out at the city’s swimming pools, an attempt was made to evaluate the effects of the two different programmes of swimming training in different intensity zones, defi ned relative to the anaerobic threshold. The examinees were divided into two groups out of 15 i.e. 17 participants who were not (according to statistics signifi cantly different in terms of average time and heart frequency during the 400 m swimming test and heart frequency and time measured after 50 m in the moment of reaching the anaerobic threshold. The fi rst training model consisted of swimming at the intensity level within the zone below anaerobic threshold, while the second model involved occasional swimming at a higher intensity sometimes surpassing the anaerobic threshold. The experimentalprogramme with both sub-groups lasted 8 weeks with 3 training sessions per week, 2 ‘of which we’re identical for both experimental groups, with the third one differing regarding the swimming intensity, this in the fi rst group being still in the zone below, and in the second group occasionally in the zone above the anaerobic threshold. The amount of training and the duration were the same in both programmes. The aim of the research , was to evaluate and to compare the effects of the two training models, using as the basic criteria possible changes of average time and heart frequency during the 400 m swimming test and heart frequency and time measured after 50 m in the moment of reaching the anaerobic thereshold. On the basis of the statistical analysis of the obtained data, it is possible to conclude that in both experimental groups there were statistically signifi cant changes of average values concerning all the physiological variables. Although the difference in effi ciency of applied experimental programmes is not defi ned, we can claim that both of experimental

  17. Swimming and other activities: applied aspects of fish swimming performance

    Science.gov (United States)

    Castro-Santos, Theodore R.; Farrell, A.P.

    2011-01-01

    Human activities such as hydropower development, water withdrawals, and commercial fisheries often put fish species at risk. Engineered solutions designed to protect species or their life stages are frequently based on assumptions about swimming performance and behaviors. In many cases, however, the appropriate data to support these designs are either unavailable or misapplied. This article provides an overview of the state of knowledge of fish swimming performance – where the data come from and how they are applied – identifying both gaps in knowledge and common errors in application, with guidance on how to avoid repeating mistakes, as well as suggestions for further study.

  18. PACING DEVICE FOR SWIMMING. MECHANICAL CONSTRUCTION OF CONSTANT SPEED

    Directory of Open Access Journals (Sweden)

    MESSINIS S.

    2010-04-01

    Full Text Available The pace in swimming is very important because it allows swimmers to allocate their forces accordingly, and therefore a distance to travel as quickly as possible. The training pace at different swimmingspeeds and combinations thereof, is an important part of training before the competitions.The definition and maintenance of the stable and swimmer specific speed is difficult to achieve and requires considerable effort and experience. To determine the desired rate of accuracy by the researchers and their coaches used till now, various audio and visual media.However, some of these institutions did not very accurately measure the rate and not all styles of swimming, while other aspects affect the proper swimming. In this construction, a key objective is to solve the problems occurring in the previous constructions, the modern technological development of them and the adaption of the specificities of different swimming styles.This device consists of an electro 3 / 8 of the horse, a flange, a single inverter from 3 / 8 to ½ of the horse, pulleys with taper Bush, flange axle, pulleys, platforms and a 52 meters cable. The assembly and operation is as follows: At the edge of the pool next to the platform is placed the base of pulleys, the electro setis connected to the inverter and the axle flange.Precisely opposite is positioned the other base. Along the pool «moves» the cable that connects the two bases, located 150 cm above the water. A fixed point on the cable is marked with paint in order to be visible to the swimmer during backstroke swimming while for other styles we adapt a lamination at the cable vertically inthe pool, above the surface a sheet of 15 cm which is painted with strong color that is visible from the athlete and will precede him. Setting the speed with inverter it starts from one end of the tank leading to the other, doing a circular motion.The swimmer is required to follow the marked point of the cable in the backstroke or

  19. The shoulder in competitive swimming.

    Science.gov (United States)

    Richardson, A B; Jobe, F W; Collins, H R

    1980-01-01

    Shoulder pain is the most common orthopaedic problem in competitive swimming. In a group of 137 of this country's best swimmers, 58 had had symptoms of "swimmer's shoulder." Population characteristics of this group indicated that symptoms increased with the caliber of the athlete, were slightly more common in men, and were related to sprint rather than distance swimming. The use of hand-paddle training exacerbated symptoms, which were more common during the early and middle season. Consideration of shoulder mechanics in swimming reveals that freestyle, butterfly, and backstroke require similar motions; a swimmer using any of these strokes is susceptible to developing shoulder pain. Swimmer's shoulder represents chronic irritation of the humeral head and rotator cuff on the coracoacromial arch during abduction of the shoulder, the so-called impingement syndrome. Treatment included stretching, rest, ice therapy, oral antiinflammatory agents, judicious use of injectable steroids, and surgery as a last resort.

  20. Paramecium swimming in capillary tube

    Science.gov (United States)

    Jana, Saikat; Um, Soong Ho; Jung, Sunghwan

    2012-04-01

    Swimming organisms in their natural habitat need to navigate through a wide range of geometries and chemical environments. Interaction with boundaries in such situations is ubiquitous and can significantly modify the swimming characteristics of the organism when compared to ideal laboratory conditions. We study the different patterns of ciliary locomotion in glass capillaries of varying diameter and characterize the effect of the solid boundaries on the velocities of the organism. Experimental observations show that Paramecium executes helical trajectories that slowly transition to straight lines as the diameter of the capillary tubes decreases. We predict the swimming velocity in capillaries by modeling the system as a confined cylinder propagating longitudinal metachronal waves that create a finite pressure gradient. Comparing with experiments, we find that such pressure gradient considerations are necessary for modeling finite sized ciliary organisms in restrictive geometries.

  1. Swimming in an Unsteady World

    Science.gov (United States)

    Koehl, M. A. R.

    2016-02-01

    When animals swim in marine habitats, the water through which they move is usually flowing. Therefore, an important part of understanding the physics of how animals swim in nature is determining how they interact with the fluctuating turbulent water currents in their environment. The research systems we have been using to address this question are microscopic marine animals swimming in turbulent, wavy water flow over spatially-complex communities of organisms growing on surfaces. Field measurements of water motion were used to design realistic turbulent flow in a laboratory wave-flume over different substrata, particle-image velocimetry was used to measure fine-scale, rapidly-varying water velocity vector fields, and planar laser-induced fluorescence was used to measure concentrations of chemical cues from the substratum. We used individual-based models of small animals swimming in this unsteady flow to determine how their trajectories and contacts with substrata were affected by their locomotion through the water, rotation by local shear, response to odors, and transport by ambient flow. We found that the shears, accelerations, and odor concentrations encountered by small swimmers fluctuate rapidly, with peaks much higher than mean values lasting fractions of a second. We identified ways in which the behavior of small, weak swimmers can bias how they are transported by ambient flow (e.g. sinking during brief encounters with shear or odor enhances settlement onto substrata below, whereas constant swimming enhances contact with surfaces above or beside larvae). Although microscopic organisms swim slowly relative to ambient water flow, their locomotory behavior in response to the rapidly-fluctuating shears and odors they encounter can affect where they are transported by ambient water movement.

  2. Swimming and Persons with Mild Persistant Asthma

    Directory of Open Access Journals (Sweden)

    Mirjana Arandelovic

    2007-01-01

    Full Text Available The aim of our study was to analyze the effect of recreational swimming on lung function and bronchial hyperresponsiveness (BHR in patients with mild persistent asthma. This study included 65 patients with mild persistent asthma, who were divided into two groups: experimental group A (n = 45 and control group B (n = 20. Patients from both groups were treated with low doses of inhaled corticosteroids (ICS and short-acting β2 agonists salbutamol as needed. Our program for patients in group A was combined asthma education with swimming (twice a week on a 1-h basis for the following 6 months. At the end of the study, in Group A, we found a statistically significant increase of lung function parameters FEV1 (forced expiratory volume in 1 sec (3.55 vs. 3.65 (p < 0.01, FVC (forced vital capacity (4.27 vs. 4.37 (p < 0.05, PEF (peak expiratory flow (7.08 vs. 7.46 (p < 0.01, and statistically significant decrease of BHR (PD20 0.58 vs. 2.01 (p < 0.001. In Group B, there was a statistically significant improvement of FEV1 3.29 vs. 3.33 (p < 0.05 and although FVC, FEV1/FVC, and PEF were improved, it was not significant. When Groups A and B were compared at the end of the study, there was a statistically significant difference of FVC (4.01 vs. 4.37, FEV1 (3.33 vs. 3.55, PEF (6.79 vs.7.46, and variability (p <0.001, and statistically significantly decreased BHR in Group A (2.01 vs. 1.75 (p < 0.001. Engagement of patients with mild persistent asthma in recreational swimming in nonchlorinated pools, combined with regular medical treatment and education, leads to better improvement of their parameters of lung function and also to more significant decrease of their airway hyperresponsiveness compared to patients treated with traditional medicine

  3. Validation of GPS and accelerometer technology in swimming.

    Science.gov (United States)

    Beanland, Emma; Main, Luana C; Aisbett, Brad; Gastin, Paul; Netto, Kevin

    2014-03-01

    To evaluate the validity of an integrated accelerometer and Global Positioning System (GPS) device to quantify swimming kinematics variables in swimming. Criterion validation study. Twenty-one sub-elite swimmers completed three 100 m efforts (one butterfly, breaststroke and freestyle) in an outdoor 50 m Olympic pool. A GPS device with an integrated tri-axial accelerometer was used to obtain mid-pool velocity and stroke count of each effort. This data was compared to velocity and stroke count data obtained from concurrently recorded digital video of the performance. A strong relationship was detected between the accelerometer stroke count and the video criterion measure for both breaststroke (r>0.98) and butterfly (r>0.99). Also, no significant differences were detected between the GPS velocity and video obtained velocity for both freestyle and breaststroke. There was a significant difference between the GPS velocity and criterion measure for butterfly. Acceptable standard error and 95% limits of agreement were obtained for freestyle (0.13 m s(-1), 0.36 m s(-1)) and breaststroke (0.12 m s(-1), 0.33 m s(-1)) compared to butterfly (0.18 m s(-1), 0.50 m s(-1)). Relative error measurements ranged between 10.2 and 13.4% across the three strokes. The integrated accelerometer and GPS device offers a valid and accurate tool for stroke count quantification in breaststroke and butterfly as well as measuring mid-pool swimming velocity in freestyle and breaststroke. The application of GPS technology in the outdoor training environment suggests advantageous practical benefits for swimmers, coaches and sports scientists. Copyright © 2013 Sports Medicine Australia. All rights reserved.

  4. Surface Waters Information Management System (SWIMS)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Surface Waters Information Management System (SWIMS) has been designed to meet multi-agency hydrologic database needs for Kansas. The SWIMS project was supported...

  5. Modelling swimming hydrodynamics to enhance performance

    OpenAIRE

    Marinho, D.A.; Rouboa, A.; Barbosa, Tiago M.; Silva, A.J.

    2010-01-01

    Swimming assessment is one of the most complex but outstanding and fascinating topics in biomechanics. Computational fluid dynamics (CFD) methodology is one of the different methods that have been applied in swimming research to observe and understand water movements around the human body and its application to improve swimming performance. CFD has been applied attempting to understand deeply the biomechanical basis of swimming. Several studies have been conducted willing to analy...

  6. Report on an investigation into heat pumps in China in fiscal 1995; 1995 nendo Chugoku ni okeru heat pump system ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The paper surveyed the present status, the status of spread, and the technical development of the technology of heat pumps for residential and industrial uses in China. Main examples of installation of heat pumps are cited below: steam drive absorption type refrigerators in Beijing; sea water heat source turbo heat pumps in Qingdao; hot water drive absorption type refrigerators in Beijing; oil-fueled absorption type water cooling and heating appliances in Beijing; ice latent heat storage airconditioning systems using electrically-driven screw chiller in Beijing; temperature rising systems using electrically-driven heat pump of the solar energy utilization warm water swimming pool in Guangdong Province; cooling water supply using waste heat utilization absorption type refrigerator of the alcohol plant in Shandong Province; timber drying systems using electrically-driven heat pump, and marine product cultivation systems in Quangdong Province; distillation systems using steam turbine heat pump in Jiangxi Province. The demand for heat pumps is expected to be 20 million units under the 9th 5-year plan, and the development of equipment is thought to go toward promotion of energy conservation, low noise, multi-type or multi-functional air conditioning equipment, and computer use. 137 figs., 40 tabs.

  7. 43 CFR 423.36 - Swimming.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Swimming. 423.36 Section 423.36 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR... Swimming. (a) You may swim, wade, snorkel, scuba dive, raft, or tube at your own risk in Reclamation waters...

  8. 36 CFR 331.10 - Swimming.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Swimming. 331.10 Section 331.10 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY REGULATIONS..., KENTUCKY AND INDIANA § 331.10 Swimming. Swimming is prohibited unless authorized in writing by the District...

  9. 36 CFR 327.5 - Swimming.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Swimming. 327.5 Section 327.5 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY RULES AND REGULATIONS... Swimming. (a) Swimming, wading, snorkeling or scuba diving at one's own risk is permitted, except at...

  10. Energetics of swimming of schooling fish

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2012-01-01

    schools. Oxygen consumption of swimming fish increases exponentially or as a power function with respect to swimming speed, and hence the decrease in oxygen saturation through the school is related to the swimming speed of the school. A model describing the oxygen saturation in a fish school from front...

  11. Energy performance of air-to-water and water-to-water heat pumps in hotel applications

    International Nuclear Information System (INIS)

    Lam, Joseph C.; Chan, Wilco W.

    2003-01-01

    We present work on measurement of the energy performance of heat pumps for hotel operations in subtropical climates. Two city hotels in Hong Kong were investigated. The first case was an application of an air-to-water heat pump to provide heating for an outdoor swimming pool during the heating season. The second case was the installation of three water-to-water heat pumps to complement an existing boiler system for hot water supply. The heating energy output and corresponding electricity use were measured. The heat pump energy efficiency was evaluated in terms of the coefficient of performance (COP), defined as the heating energy output to the electrical energy use. The air-to-water heat pump provided 49.1 MW h heating while consuming 24.6 MW h electricity during the 6((1)/(2))-month heating season from mid-October to April. For the water-to-water heat pumps, the estimated annual heating output and the electricity use were 952 and 544 MW h, respectively. It was found that the heat pumps generally operated in a COP range of 1.5-2.4, and the payback period was about two years, which was considered financially attractive

  12. The influence of elements of synchronized swimming on technique of the selected swimming strokes

    OpenAIRE

    Široký, Michal

    2015-01-01

    Title: The influence of elements of synchronized swimming on technique of the selected swimming strokes Objectives: The objective of the thesis is to assess the effect of the elements of synchronized swimming at improving the techniques of swimming. Methods: The results were detected by overt observation with active participation and subsequent scaling on the ordinal scale 1 to 5. Results: The results show that the influence of the elements of synchronized swimming on improving the technique ...

  13. The hydrodynamics of swimming microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Lauga, Eric [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093-0411 (United States); Powers, Thomas R [Division of Engineering, Brown University, Providence, RI 02912-9104 (United States)], E-mail: elauga@ucsd.edu, E-mail: Thomas_Powers@brown.edu

    2009-09-15

    Cell motility in viscous fluids is ubiquitous and affects many biological processes, including reproduction, infection and the marine life ecosystem. Here we review the biophysical and mechanical principles of locomotion at the small scales relevant to cell swimming, tens of micrometers and below. At this scale, inertia is unimportant and the Reynolds number is small. Our emphasis is on the simple physical picture and fundamental flow physics phenomena in this regime. We first give a brief overview of the mechanisms for swimming motility, and of the basic properties of flows at low Reynolds number, paying special attention to aspects most relevant for swimming such as resistance matrices for solid bodies, flow singularities and kinematic requirements for net translation. Then we review classical theoretical work on cell motility, in particular early calculations of swimming kinematics with prescribed stroke and the application of resistive force theory and slender-body theory to flagellar locomotion. After examining the physical means by which flagella are actuated, we outline areas of active research, including hydrodynamic interactions, biological locomotion in complex fluids, the design of small-scale artificial swimmers and the optimization of locomotion strategies.

  14. The hydrodynamics of swimming microorganisms

    International Nuclear Information System (INIS)

    Lauga, Eric; Powers, Thomas R

    2009-01-01

    Cell motility in viscous fluids is ubiquitous and affects many biological processes, including reproduction, infection and the marine life ecosystem. Here we review the biophysical and mechanical principles of locomotion at the small scales relevant to cell swimming, tens of micrometers and below. At this scale, inertia is unimportant and the Reynolds number is small. Our emphasis is on the simple physical picture and fundamental flow physics phenomena in this regime. We first give a brief overview of the mechanisms for swimming motility, and of the basic properties of flows at low Reynolds number, paying special attention to aspects most relevant for swimming such as resistance matrices for solid bodies, flow singularities and kinematic requirements for net translation. Then we review classical theoretical work on cell motility, in particular early calculations of swimming kinematics with prescribed stroke and the application of resistive force theory and slender-body theory to flagellar locomotion. After examining the physical means by which flagella are actuated, we outline areas of active research, including hydrodynamic interactions, biological locomotion in complex fluids, the design of small-scale artificial swimmers and the optimization of locomotion strategies.

  15. Sports Medicine Meets Synchronized Swimming.

    Science.gov (United States)

    Wenz, Betty J.; And Others

    This collection of articles contains information about synchronized swimming. Topics covered include general physiology and cardiovascular conditioning, flexibility exercises, body composition, strength training, nutrition, coach-athlete relationships, coping with competition stress and performance anxiety, and eye care. Chapters are included on…

  16. Fluid Mechanics of Fish Swimming

    Indian Academy of Sciences (India)

    user

    shark). Redrawn from Review of Fish. Swimming Modes for Aquatic. Locomotion, IEEE Journal of. Oceanic Engineering, Vol.24,. No.2, pp. 237–252, 1999, D M. Lane, M Sfakiotakis and J B C. Davies, Heriot-Watt University. undulatory → oscillatory caudaltail¯n (B C F ) m otions are know n collectively as. B C F sw im m ers.

  17. Shape Optimization of Swimming Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Wilkening, J.; Hosoi, A.E.

    2005-03-01

    The swimming behavior of a flexible sheet which moves by propagating deformation waves along its body was first studied by G. I. Taylor in 1951. In addition to being of theoretical interest, this problem serves as a useful model of the locomotion of gastropods and various micro-organisms. Although the mechanics of swimming via wave propagation has been studied extensively, relatively little work has been done to define or describe optimal swimming by this mechanism.We carry out this objective for a sheet that is separated from a rigid substrate by a thin film of viscous Newtonian fluid. Using a lubrication approximation to model the dynamics, we derive the relevant Euler-Lagrange equations to optimize swimming speed and efficiency. The optimization equations are solved numerically using two different schemes: a limited memory BFGS method that uses cubic splines to represent the wave profile, and a multi-shooting Runge-Kutta approach that uses the Levenberg-Marquardt method to vary the parameters of the equations until the constraints are satisfied. The former approach is less efficient but generalizes nicely to the non-lubrication setting. For each optimization problem we obtain a one parameter family of solutions that becomes singular in a self-similar fashion as the parameter approaches a critical value. We explore the validity of the lubrication approximation near this singular limit by monitoring higher order corrections to the zeroth order theory and by comparing the results with finite element solutions of the full Stokes equations.

  18. Fluid Mechanics of Fish Swimming

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 1. Fluid Mechanics of Fish Swimming - Lift-based Propulsion. Jaywant H Arakeri. General Article Volume 14 Issue 1 January 2009 pp 32-46. Fulltext. Click here to view fulltext PDF. Permanent link:

  19. Sodium bicarbonate improves swimming performance.

    Science.gov (United States)

    Lindh, A M; Peyrebrune, M C; Ingham, S A; Bailey, D M; Folland, J P

    2008-06-01

    Sodium bicarbonate ingestion has been shown to improve performance in single-bout, high intensity events, probably due to an increase in buffering capacity, but its influence on single-bout swimming performance has not been investigated. The effects of sodium bicarbonate supplementation on 200 m freestyle swimming performance were investigated in elite male competitors. Following a randomised, double blind counterbalanced design, 9 swimmers completed maximal effort swims on 3 separate occasions: a control trial (C); after ingestion of sodium bicarbonate (SB: NaHCO3 300 mg . kg (-1) body mass); and after ingestion of a placebo (P: CaCO3 200 mg . kg (-1) body mass). The SB and P agents were packed in gelatine capsules and ingested 90 - 60 min prior to each 200 m swim. Mean 200 m performance times were significantly faster for SB than C or P (1 : 52.2 +/- 4.7; 1 : 53.7 +/- 3.8; 1 : 54.0 +/- 3.6 min : ss; p bicarbonate were all elevated pre-exercise in the SB compared to C and P trials (p < 0.05). Post-200 m blood lactate concentrations were significantly higher following the SB trial compared with P and C (p < 0.05). It was concluded that SB supplementation can improve 200 m freestyle performance time in elite male competitors, most likely by increasing buffering capacity.

  20. Fluid Mechanics of Fish Swimming

    Indian Academy of Sciences (India)

    user

    forces generated by their °apping tails. A nguilliform sw im m .... In natural systems, like a human walking or a ¯sh swimming, there is always unsteadiness. ... (L) mainly from the wings balances the weight (W). b) For the fish shown here the thrust is mainly from the flapping tail. Lift from fins and buoyancy (FB ) bal- ance the ...

  1. The Effect of Swimming Experience on Acquisition and Retention of Swimming-Based Taste Aversion Learning in Rats

    Science.gov (United States)

    Masaki, Takahisa; Nakajima, Sadahiko

    2010-01-01

    Swimming endows rats with an aversion to a taste solution consumed before swimming. The present study explored whether the experience of swimming before or after the taste-swimming trials interferes with swimming-based taste aversion learning. Experiment 1 demonstrated that a single preexposure to 20 min of swimming was as effective as four or…

  2. Pool Boiling CHF in Inclined Narrow Annuli

    International Nuclear Information System (INIS)

    Kang, Myeong Gie

    2010-01-01

    Pool boiling heat transfer has been studied extensively since it is frequently encountered in various heat transfer equipment. Recently, it has been widely investigated in nuclear power plants for application to the advanced light water reactors designs. Through the review on the published results it can be concluded that knowledge on the combined effects of the surface orientation and a confined space on pool boiling heat transfer is of great practical importance and also of great academic interest. Fujita et al. investigated pool boiling heat transfer, from boiling inception to the critical heat flux (CHF, q' CHF ), in a confined narrow space between heated and unheated parallel rectangular plates. They identified that both the confined space and the surface orientation changed heat transfer much. Kim and Suh changed the surface orientation angles of a downward heating rectangular channel having a narrow gap from the downward-facing position (180 .deg.) to the vertical position (90 .deg.). They observed that the CHF generally decreased as the inclination angle (θ ) increased. Yao and Chang studied pool boiling heat transfer in a confined heat transfer for vertical narrow annuli with closed bottoms. They observed that when the gap size ( s ) of the annulus was decreased the effect of space confinement to boiling heat transfer increased. The CHF was occurred at much lower value for the confined space comparing to the unconfined pool boiling. Pool boiling heat transfer in narrow horizontal annular crevices was studied by Hung and Yao. They concluded that the CHF decreased with decreasing gap size of the annuli and described the importance of the thin film evaporation to explain the lower CHF of narrow crevices. The effect of the inclination angle on the CHF on countercurrent boiling in an inclined uniformly heated tube with closed bottoms was also studied by Liu et al. They concluded that the CHF reduced with the inclination angle decrease. A study was carried out

  3. Influence of mobile games on the process of teaching of students that can not swim

    OpenAIRE

    Strelnykov G.L.; Lozgachov G.V.; Strelnykova Y.Y.

    2012-01-01

    Considered direction in teaching of students to swimming in terms 25 meter pool. 30 students took part in an experiment. The place of mobile games in the process of teaching of novices is certain. Information of results of testing of level of physical preparedness of students is presented. Positive influence of mobile games on the process of mastering of skills of swimming and co-operations on water is marked. Forms and methods of mastering of skills and conduct in water are offered. The moti...

  4. Pre-task music improves swimming performance.

    Science.gov (United States)

    Smirmaul, B P; Dos Santos, R V; Da Silva Neto, L V

    2015-12-01

    The purpose of this study was to investigate the effects of pre-task music on swimming performance and other psychological variables. A randomized counterbalanced within-subjects (experimental and control condition) design was employed. Eighteen regional level male swimmers performed two 200-m freestyle swimming time trials. Participants were exposed to either 5 minutes of self-selected music (pre-task music condition) or 5 minutes of silence (control condition) and, after 1 minute, performed the swimming task. Swimming time was significantly shorter (-1.44%) in the pre-task music condition. Listening to pre-task music increased motivation to perform the swimming task, while arousal remained unchanged. While fatigue increased after the swimming task in both conditions, vigor, ratings of perceived exertion and affective valence were unaltered. It is concluded, for the first time, that pre-task music improves swimming performance.

  5. Biomechanical analysis of backstroke swimming starts.

    Science.gov (United States)

    de Jesus, K; de Jesus, K; Figueiredo, P; Gonçalves, P; Pereira, S; Vilas-Boas, J P; Fernandes, R J

    2011-07-01

    The relationships between the start time and kinematic, kinetic and electromyographic data were examined in order to establish the common features of an effective backstroke swimming start. Complementarily, different starting positions were analysed to identify the parameters that account for the fastest backstroke start time under different constraints. 6 high-level swimmers performed 4×15 m maximal trials of each start variants with different feet position: parallel and entirely submerged (BSFI) and above water surface (BSFE), being monitored with synchronized dual-media image, underwater platform plus handgrip with a load cell, and eletromyographic signal of RECTUS FEMORIS and GASTROCNEMIUS MEDIALIS. Mean and SD values of start time for BSFI and BSFE were 2.03 ± 0.19 and 2.14 ± 0.36 s, respectively. In both starts, high associations (r > =0.75, p < 0.001) were observed between start time and centre of mass resultant average velocity at glide phase and horizontal impulse at take-off for BSFI, and centre of mass horizontal position at the start signal for BSFE. It was concluded that the greater impulse during the take-off and its transformation into a fast underwater movement are determinant to decrease the start time at BSFI. Regarding BSFE, a greater centre of mass pool-wall approximation might imply a flatter take-off angle, compromising underwater velocity and starting performance. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Technical support document: Energy efficiency standards for consumer products: Room air conditioners, water heaters, direct heating equipment, mobile home furnaces, kitchen ranges and ovens, pool heaters, fluorescent lamp ballasts and television sets. Volume 3, Water heaters, pool heaters, direct heating equipment, and mobile home furnaces

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    This is Volume 3 in a series of documents on energy efficiency of consumer products. This volume discusses energy efficiency of water heaters. Water heaters are defined by NAECA as products that utilize oil, gas, or electricity to heat potable water for use outside the heater upon demand. These are major appliances, which use a large portion (18% on average) of total energy consumed per household (1). They differ from most other appliances in that they are usually installed in obscure locations as part of the plumbing and are ignored until they fail. Residential water heaters are capable of heating water up to 180{degrees}F, although the setpoints are usually set lower.

  7. Direct Heat Utilization of Geothermal Resources Worldwide 2005

    Energy Technology Data Exchange (ETDEWEB)

    Lund, John W.

    2000-01-01

    Direct utilization of geothermal energy consists of various forms for heating and cooling instead of converting the energy for electric power generation. The geothermal resources that can be utilized are in the lower temperature range that are more wide-spread than the higher temperature resources used for electricity generation. The major areas of direct utilization are: heating of swimming pools and for balneology; space heating and cooling including district heating; agriculture applications (greenhouse heating and crop drying); aquaculture applications; industrial processing; and geothermal heat pumps. Direct utilization projects are reported in 72 countries with an installed capacity of 28,268 MWt and annual energy use of 273,372 TJ (75,943 GWh) reported in 2005. The equivalent annual savings in fuel oil amounts to 170 million barrels (25.4 million tonnes) and 24 million tonnes in carbon emissions to the atmosphere. Recent trends are to combined geothermal heat and power projects in order to maximize the use of the resource and improve the economics of the project. With the recent increases in fossil fuel prices, it is estimated that direct utilizations will more than double in the next 10 years.

  8. New possibilities and perspectives of building hotwater line from geothermal wells heat exchanger to TEKO Košice

    Directory of Open Access Journals (Sweden)

    Marína Sidorová

    2006-04-01

    Full Text Available Thank to favourable geological conditions, Slovakia is a country abundant in the occurrence of low-enthalpy sources. The government of the state sponsors new renewable of the sources ecological energy,including the geothermal energy. Geothermal water is utilized for recreation (swimming pools, spas, agriculture (heating of greenhouses, fishing and heating of houses. The effectivity of utilisation is about 30 % due to its seasonal use. That is why the annual house-heating and the hot water supply from geothermal sources are supported. Recently, the company Slovgeoterm has initiated heating of greenhouses in Podhajska and hospital and 1231 flats in the town Galanta. Nowadays, a research for the biggest geothermal project in the Middle Europe – construction in Košice basin has started.

  9. Nutritional recommendations for synchronized swimming.

    Science.gov (United States)

    Robertson, Sherry; Benardot, Dan; Mountjoy, Margo

    2014-08-01

    The sport of synchronized swimming is unique, because it combines speed, power, and endurance with precise synchronized movements and high-risk acrobatic maneuvers. Athletes must train and compete while spending a great amount of time underwater, upside down, and without the luxury of easily available oxygen. This review assesses the scientific evidence with respect to the physiological demands, energy expenditure, and body composition in these athletes. The role of appropriate energy requirements and guidelines for carbohydrate, protein, fat, and micronutrients for elite synchronized swimmers are reviewed. Because of the aesthetic nature of the sport, which prioritizes leanness, the risks of energy and macronutrient deficiencies are of significant concern. Relative Energy Deficiency in Sport and disordered eating/eating disorders are also of concern for these female athletes. An approach to the healthy management of body composition in synchronized swimming is outlined. Synchronized swimmers should be encouraged to consume a well-balanced diet with sufficient energy to meet demands and to time the intake of carbohydrate, protein, and fat to optimize performance and body composition. Micronutrients of concern for this female athlete population include iron, calcium, and vitamin D. This article reviews the physiological demands of synchronized swimming and makes nutritional recommendations for recovery, training, and competition to help optimize athletic performance and to reduce risks for weight-related medical issues that are of particular concern for elite synchronized swimmers.

  10. Cetacean Swimming with Prosthetic Limbs

    Science.gov (United States)

    Bode-Oke, Ayodeji; Ren, Yan; Dong, Haibo; Fish, Frank

    2016-11-01

    During entanglement in fishing gear, dolphins can suffer abrasions and amputations of flukes and fins. As a result, if the dolphin survives the ordeal, swimming performance is altered. Current rehabilitation technques is the use of prosthesis to regain swimming ability. In this work, analyses are focused on two dolphins with locomotive impairment; Winter (currently living in Clearwater Marine Aquarium in Florida) and Fuji (lived in Okinawa Churaumi Aquarium in Japan). Fuji lost about 75% of its fluke surface to necrosis (death of cells) and Winter lost its tail due to amputation. Both dolphins are aided by prosthetic tails that mimic the shape of a real dolphin tail. Using 3D surface reconstruction techniques and a high fidelity Computational Fluid Dynamics (CFD) flow solver, we were able to elucidate the kinematics and hydrodynamics and fluke deformation of these swimmers to clarify the effectiveness of prostheses in helping the dolphins regain their swimming ability. Associated with the performance, we identified distinct features in the wake structures that can explain this gap in the performance compared to a healthy dolphin. This work was supported by ONR MURI Grant Number N00014-14-1-0533.

  11. Collaborative Car Pooling System

    OpenAIRE

    João Ferreira; Paulo Trigo; Porfírio Filipe

    2009-01-01

    This paper describes the architecture for a collaborative Car Pooling System based on a credits mechanism to motivate the cooperation among users. Users can spend the accumulated credits on parking facilities. For this, we propose a business model to support the collaboration between a car pooling system and parking facilities. The Portuguese Lisbon-s Metropolitan area is used as application scenario.

  12. Hospital hydrotherapy pools treated with ultra violet light: bad bacteriological quality and presence of thermophilic Naegleria.

    Science.gov (United States)

    De Jonckheere, J F

    1982-04-01

    The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management. On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was present in very high numbers. Halogenated hydrotherapy pools were not highly contaminated with amoebae, and Naegleria spp. were never detected. On the other hand u.v.-treated pools contained very high numbers of thermophilic Naegleria. The Naegleria isolated were identified as N. lovaniensis, a species commonly found in association with N. fowleri. Isoenzyme analysis showed a different type of N. lovaniensis was present in each of two u.v.-treated pools.

  13. Hospital hydrotherapy pools treated with ultra violet light: bad bacteriological quality and presence of thermophilic Naegleria.

    Science.gov (United States)

    De Jonckheere, J. F.

    1982-01-01

    The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management. On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was present in very high numbers. Halogenated hydrotherapy pools were not highly contaminated with amoebae, and Naegleria spp. were never detected. On the other hand u.v.-treated pools contained very high numbers of thermophilic Naegleria. The Naegleria isolated were identified as N. lovaniensis, a species commonly found in association with N. fowleri. Isoenzyme analysis showed a different type of N. lovaniensis was present in each of two u.v.-treated pools. Images Plate 1 PMID:7061835

  14. Radioisotope Power System Pool Concept

    Science.gov (United States)

    Rusick, Jeffrey J.; Bolotin, Gary S.

    2015-01-01

    Advanced Radioisotope Power Systems (RPS) for NASA deep space science missions have historically used static thermoelectric-based designs because they are highly reliable, and their radioisotope heat sources can be passively cooled throughout the mission life cycle. Recently, a significant effort to develop a dynamic RPS, the Advanced Stirling Radioisotope Generator (ASRG), was conducted by NASA and the Department of Energy, because Stirling based designs offer energy conversion efficiencies four times higher than heritage thermoelectric designs; and the efficiency would proportionately reduce the amount of radioisotope fuel needed for the same power output. However, the long term reliability of a Stirling based design is a concern compared to thermoelectric designs, because for certain Stirling system architectures the radioisotope heat sources must be actively cooled via the dynamic operation of Stirling converters throughout the mission life cycle. To address this reliability concern, a new dynamic Stirling cycle RPS architecture is proposed called the RPS Pool Concept.

  15. Condensation in a two-phase pool

    International Nuclear Information System (INIS)

    Duffey, R.B.; Hughes, E.D.

    1991-01-01

    We consider the case of vapor condensation in a liquid pool, when the heat transfer is controlled by heat losses through the walls. The analysis is based on drift flux theory for phase separation in the pool, and determines the two-phase mixture height for the pool. To our knowledge this is the first analytical treatment of this classic problem that gives an explicit result, previous work having established the result for the evaporative case. From conservation of mass and energy in a one-dimensional steady flow, together with a void relation between the liquid and vapor fluxes, we determine the increase in the mixture level from the base level of the pool. It can be seen that the thermal and hydrodynamic influences are separable. Thus, the thermal influence of the wall heat transfer appears through its effect on the condensing length L*, so that at high condensation rates the pool is all liquid, and at low rates overflows (the level swell or foaming effect). Similarly, the phase separation effect hydrodynamically determines the height via the relative velocity of the mixture to the entering flux. We examine some practical applications of this result to level swell in condensing flows, and also examine some limits in ideal cases

  16. The influence of explosive power on the performance of an elite swimmer in 25 and 50 metre pools

    Directory of Open Access Journals (Sweden)

    Simona Baumrtová

    2017-11-01

    Full Text Available Each swimming stroke, and each distance, requires a different approach to strength training. For sprinters in swimming the most essential part is explosive power. The goal of this case study was to find out how explosive training can influence the performance in both long course and short course meters swimming pools. This study was conducted with the cooperation of an elite swimmer over a time period of 6 years. Tests were performed twice a year (June and November during the years of 2010–2016. The Myotest device was used to measure countermovement jump height. Swimming performance was evaluated by FINA points in the swimmer’s three main disciplines. ANOVA, Cohen’s d and regression equation were used for statistical analysis. The results showed that explosive power does not influence performance in the 50m swimming pool (p = 0.25; r2 = 0.08. However the performance in the 25m pool is directly linked to the level of explosive power of the lower limbs (p < 0.001; r2 = 0.85. The results of the swimmer in the 25m pool are closely related to the level of explosive power of the lower limbs. Performance in the 50m pool might not be affected by level of lower limb power.

  17. Vortex re-capturing and kinematics in human underwater undulatory swimming.

    Science.gov (United States)

    Hochstein, Stefan; Blickhan, Reinhard

    2011-10-01

    To maximize swimming speed athletes copy fish undulatory swimming during the underwater period after start and turn. The anatomical limitations may lead to deviations and may enforce compensating strategies. This has been investigated by analyzing the kinematics of two national female swimmers while swimming in a still water pool. Additionally, the flow around and behind the swimmers was measured with the aid of time-resolved particle image velocimetry (TR-2D-PIV). As compared to fish, the swimmers used undulatory waves characterized by much higher Strouhal numbers but very similar amplitude distributions along the body and Froude efficiencies. Vortices generated in the region of strongly flexing joints are suitable to be used pedally to enhance propulsion (vortex re-capturing). Complementing studies using numerical and technical modeling will help us to probe the efficiency of observed mechanisms and further improvements of the human strategy. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Kinematics of swimming garter snakes (Thamnophis sirtalis).

    Science.gov (United States)

    Munk, Yonatan

    2008-06-01

    We investigate the kinematics of swimming garter snakes (Thamnophis sirtalis) using a novel nonlinear regression-based digitization method to establish quantitative statistical support for non-constant wavelengths in the undulatory pattern exhibited by swimming snakes. We find that in swimming snakes, the growth of the amplitude of the propulsive wave head-to-tail is strongly correlated (p < 0.005) with the head-to-tail growth in the wavelength. We investigate correlations between kinematic parameters and steady swimming speed, and find a very strong positive correlation between swimming speed and undulation frequency. We furthermore find a statistically well-supported positive correlation between swimming speed and both the initial amplitude of the propulsive wave at the head and the degree of amplitude growth from head to tail.

  19. Measurements of fluid flow in weld pools

    NARCIS (Netherlands)

    Zhao, C.

    2011-01-01

    Understanding the fluid flow in weld pools contributes significantly toward controlling the heat distribution in the base material and the mass distribution of molten base and additive materials. Currently, most investigations focus primarily on numerical models, due to the experimental difficulties

  20. Enhanced active swimming in viscoelastic fluids

    OpenAIRE

    Riley, Emily E; Lauga, Eric Jean-Marie

    2014-01-01

    Swimming microorganisms often self propel in fluids with complex rheology. While past theoretical work indicates that fluid viscoelasticity should hinder their locomotion, recent experiments on waving swimmers suggest a possible non-Newtonian enhancement of locomotion. We suggest a physical mechanism, based on fluid-structure interaction, leading to swimming in a viscoelastic fluid at a higher speed than in a Newtonian one. Using Taylor's two-dimensional swimming sheet model, we solve for the...

  1. HYDRODINAMICS AND SWIMMING TEHNIQUE AS PARAMETERS FOR SUCCESSFULL SWIMMING AT THE AGE 10–12

    Directory of Open Access Journals (Sweden)

    Goran Dimitrić

    2008-08-01

    Full Text Available The aim of this study was to confirm that swimming technique and hydrodynamic parameters of a swimmer are relevant for successful swimming. Total of 63 boys, at the age of 10-12, participated in this research. There were 15 criterion morphology and specific motoric skills variables as well as one predictive variable derived from FINA points. We have concluded that hydrodynamic and swimming technique significantly contributes for successful swimming. These facts should use trainers as guidance for workout plan.

  2. PDA: Pooled DNA analyzer

    Directory of Open Access Journals (Sweden)

    Lin Chin-Yu

    2006-04-01

    Full Text Available Abstract Background Association mapping using abundant single nucleotide polymorphisms is a powerful tool for identifying disease susceptibility genes for complex traits and exploring possible genetic diversity. Genotyping large numbers of SNPs individually is performed routinely but is cost prohibitive for large-scale genetic studies. DNA pooling is a reliable and cost-saving alternative genotyping method. However, no software has been developed for complete pooled-DNA analyses, including data standardization, allele frequency estimation, and single/multipoint DNA pooling association tests. This motivated the development of the software, 'PDA' (Pooled DNA Analyzer, to analyze pooled DNA data. Results We develop the software, PDA, for the analysis of pooled-DNA data. PDA is originally implemented with the MATLAB® language, but it can also be executed on a Windows system without installing the MATLAB®. PDA provides estimates of the coefficient of preferential amplification and allele frequency. PDA considers an extended single-point association test, which can compare allele frequencies between two DNA pools constructed under different experimental conditions. Moreover, PDA also provides novel chromosome-wide multipoint association tests based on p-value combinations and a sliding-window concept. This new multipoint testing procedure overcomes a computational bottleneck of conventional haplotype-oriented multipoint methods in DNA pooling analyses and can handle data sets having a large pool size and/or large numbers of polymorphic markers. All of the PDA functions are illustrated in the four bona fide examples. Conclusion PDA is simple to operate and does not require that users have a strong statistical background. The software is available at http://www.ibms.sinica.edu.tw/%7Ecsjfann/first%20flow/pda.htm.

  3. Status report on direct heat and low temperature utilization of geothermal energy in New Zealand

    International Nuclear Information System (INIS)

    Lumb, J.T.; Clelland, L.

    1990-01-01

    The Tasman Pulp and Paper Company's mill at Kawerau continues to be the dominant direct user of geothermal energy in New Zealand. Recent plant changes have increased the effectiveness of the company's use of the resource. Other uses are relatively small in scale and include air and water heating for homes, motels and other commercial and industrial premises. Commercial swimming-pool complexes and pools at hotels, motels and private homes are the other major direct users. This paper reports that overall direct use of the resource has shown a slow increase during the last five years except at Rotorua where the enforced closure of bores has led to more than 70% reduction in use

  4. The Swimming Ability of Children with Asthma

    Directory of Open Access Journals (Sweden)

    Benčuriková Ľubomíra

    2017-05-01

    Full Text Available This paper reports on findings of a pilot research to determine the level of swimming ability of children with weak respiratory system aged between 10 - 11 years, who attended special classes for asthmatics. Swimming ability was assessed by 25 m free style swimming test. The results of asthmatics were compared with healthy peers (Benčuriková 2006; Kováčová 2010; Labudová 2011. The results confirmed that the level of swimming capability of asthmatic children, despite their handicap, is significantly higher than their healthy peers.

  5. Tethered swimming can be used to evaluate force contribution for short-distance swimming performance.

    Science.gov (United States)

    Morouço, Pedro G; Marinho, Daniel A; Keskinen, Kari L; Badillo, Juan J; Marques, Mário C

    2014-11-01

    The purpose of this study was two-fold: (a) to compare stroke and the physiological responses between maximal tethered and free front crawl swimming and (b) to evaluate the contribution of force exertion for swimming performance over short distances. A total of 34 male swimmers, representing various levels of competitive performance, participated in this study. Each participant was tested in both a 30-second maximal tethered swimming test and a 50-m free swimming test. The tethered force parameters, the swimming speed, stroke (stroke rate [SR]), and the physiological responses (increase in blood lactate concentration [ΔBLa], heart rate, and rate of perceived exertion) were recorded and calculated. The results showed no differences in stroke and the physiological responses between tethered and free swimming, with a high level of agreement for the SR and ΔBLa. A strong correlation was obtained between the maximum impulse of force per stroke and the speed (r = 0.91; p swimming performance. The relationship between the swimming speed and maximum force tended to be nonlinear, whereas linear relationships were observed with the maximum impulse. This study demonstrates that tethered swimming does not significantly alter stroke and the physiological responses compared with free swimming, and that the maximum impulse per stroke should be used to evaluate the balance between force and the ability to effectively apply force during sprint swimming. Consequently, coaches can rely on tethered forces to identify strength deficits and improve swimming performance over short distances.

  6. 75 FR 65261 - Virginia Graeme Baker Pool and Spa Safety Act; Public Accommodation

    Science.gov (United States)

    2010-10-22

    ... spa'' in relevant part as a ``swimming pool or spa that is open exclusively to patrons of a hotel or... proposed interpretive rule would interpret ``public accommodations facility'' to mean: ``An inn, hotel... accommodations facility'' as ``an inn, hotel, motel, or other place of lodging, including, but not limited to...

  7. What’s In the Pool? (A Cup of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2013-05-30

    As summer approaches, more and more people will head to the pool, but dangers lurk in the form of waterborne diseases. In this podcast, Michele Hlavsa discusses ways to avoid waterborne diseases while swimming.  Created: 5/30/2013 by MMWR.   Date Released: 5/30/2013.

  8. Use of employments on swimming in pulling in and restoration microcycles in the training process of the highly skilled sportsmen of the highly skilled heavy weight sambo wrestlers

    Directory of Open Access Journals (Sweden)

    I.P. Zakorko

    2013-02-01

    Full Text Available Expedience of the use of the sporting and health swimming is grounded in precontest preparation of the highly skilled sportsmen unarmed self-defence. 10 sportsmen took part in research (weight over 90 kg. Offered to recommendation on the use of swimming in renewal of sportsmen after the competition and trainings loadings. On employments, swimming was utillized a method crawl on a breast and by a method breast-stroke. Length of path of pool is 25 meters. The level of influence of trainings is set on swimming of different orientation on the general consisting of the sportsman unarmed self-defence of context of preparation and renewal during the specialized competition activity. It is recommended in training on swimming to utillize overcoming at full pelt of cutting-off 250 meters in the mode to 5 minutes (time of competition fight is in the fight of sambo-5 of minutes.

  9. Vitamin D Pooling Project

    Science.gov (United States)

    The Vitamin D Pooling Project of Rarer Cancers brought together investigators from 10 cohorts to conduct a large prospective epidemiologic study of the association between vitamin D status and seven rarer cancers.

  10. Knee pain in competitive swimming.

    Science.gov (United States)

    Rodeo, S A

    1999-04-01

    The high volume of training in competitive swimming results in cumulative overload injuries. Knee pain ranks second to shoulder pain as a common complaint in competitive swimmers. Most knee pain occurs on the medial side of the knee and, most commonly, in breaststroke swimmers; however, knee pain may accompany all strokes. This article reviews the incidence of knee pain, the biomechanic and anatomic factors predisposing to injury, specific injury patterns, injury diagnosis, and the treatment and prevention of injury to the knee in swimmers.

  11. Mechanical power, thrust power and propelling efficiency: relationships with elite sprint swimming performance.

    Science.gov (United States)

    Gatta, Giorgio; Cortesi, Matteo; Swaine, Ian; Zamparo, Paola

    2018-03-01

    The purpose of this study was to explore the relationships between mechanical power, thrust power, propelling efficiency and sprint performance in elite swimmers. Mechanical power was measured in 12 elite sprint male swimmers: (1) in the laboratory, by using a whole-body swimming ergometer (W' TOT ) and (2) in the pool, by measuring full tethered swimming force (F T ) and maximal swimming velocity (V max ): W' T  = F T  · V max . Propelling efficiency (η P ) was estimated based on the "paddle wheel model" at V max . V max was 2.17 ± 0.06 m · s -1 , η P was 0.39 ± 0.02, W' T was 374 ± 62 W and W' TOT was 941 ± 92 W. V max was better related to W' T (useful power output: R = 0.943, P swimming performance. The ratio W' T /W' TOT (0.40 ± 0.04) represents the fraction of total mechanical power that can be utilised in water (e.g., η P ) and was indeed the same as that estimated based on the "paddle wheel model"; this supports the use of this model to estimate η P in swimming.

  12. Halliwickov koncept učenja plavanja in ocenjevanje plavalnih veščin: The Halliwick concept of teaching of swimming and assessment of swimming skills: The Halliwick concept of teaching of swimming and assessment of swimming skills:

    OpenAIRE

    Groleger, Katja; Vidmar, Gaj; Vrečar, Irena

    2010-01-01

    The Halliwick concept of teaching of swimming is a comprehensive programme of adaptation to water, learning to breathe, moving in water and swimming, aimed mainly at persons with movement and/or learning disabilities of different age. Assessment of swimming ability is an integral part of the Halliwick concept. The system of Halliwick badges is used, which has recently been supplemented by the Swimming With Independent Measurement (SWIM). There is no data on sensitivity of the SWIM test in the...

  13. Overview of pool hydraulic design of Indian prototype fast breeder ...

    Indian Academy of Sciences (India)

    gas transportation through heat exchangers (IHX) and pump to grid plate, agglomeration of gas inside grid plate ... During plant transients associated with one secondary loop, temperature in the cold pool associated with ... Flow coast down characteristics of secondary sodium pump (SSP in figure 1) and cold pool capacity ...

  14. Strouhal number for free swimming

    Science.gov (United States)

    Saadat, Mehdi; van Buren, Tyler; Floryan, Daniel; Smits, Alexander; Haj-Hariri, Hossein

    2015-11-01

    In this work, we present experimental results to explore the implications of free swimming for Strouhal number (as an outcome) in the context of a simple model for a fish that consists of a 2D virtual body (source of drag) and a 2D pitching foil (source of thrust) representing cruising with thunniform locomotion. The results validate the findings of Saadat and Haj-Hariri (2012): for pitching foils thrust coefficient is a function of Strouhal number for all gaits having amplitude less than a certain critical value. Equivalently, given the balance of thrust and drag forces at cruise, Strouhal number is only a function of the shape, i.e. drag coefficient and area, and essentially a constant for high enough swimming speeds for which the mild dependence of drag coefficient on the speed vanishes. Furthermore, a dimensional analysis generalizes the findings. A scaling analysis shows that the variation of Strouhal number with cruising speed is functionally related to the variation of body drag coefficient with speed. Supported by ONR MURI Grant N00014-14-1-0533.

  15. Growing swimming algae for bioenergy

    Science.gov (United States)

    Croze, Ottavio

    Biofuel production from photosynthetic microalgae is not commercially viable due to high processing costs. New engineering and biological solutions are being sought to reduce these costs by increasing processing efficiency (productivity per energy input). Important physics, however, is ignored. For example, the fluid dynamics of algal suspensions in photobioreactors (ponds or tube arrays) is non-trivial, particularly if the algae swim. Cell reorientation by passive viscous and gravitational torques (gyrotaxis) or active reorientation by light (phototaxis) cause swimming algae in suspension to structure in flows, even turbulent ones. This impacts the distribution and dispersion of swimmers, with significant consequences for photobioreactor operation and design. In this talk, I will describe a theory that predicts swimmer dispersion in laminar pipe flows. I will then then present experimental tests of the theory, as well as new results on the circadian suspension dynamics of the algaChlamydomonas reinhardtii in lab-scale photobioreactors. Finally, I will briefly consider the implications of our work, and related active matter research, for improving algal bioprocessing efficiency. Winton Programme for the Physics of Sustainability.

  16. Basic Land Drills for Swimming Stroke Acquisition

    Science.gov (United States)

    Zhang, Peng

    2014-01-01

    Teaching swimming strokes can be a challenging task in physical education. The purpose of the article is to introduce 12 on land drills that can be utilized to facilitate the learning of swimming strokes, including elementary back stroke, sidestroke, front crawl, back stroke, breaststroke, and butterfly. Each drill consists of four components…

  17. Propulsive force in front crawl swimming

    NARCIS (Netherlands)

    Berger, M.A.M.; de Groot, G.; Hollander, A.P.

    1999-01-01

    To evaluate the propulsive forces in front crawl arm swimming, derived from a three-dimensional kinematic analysis, these values were compared with mean drag forces. The propulsive forces during front crawl swimming using the arms only were calculated using three-dimensional kinematic analysis

  18. Swimming and muscle structure in fish

    NARCIS (Netherlands)

    Spierts, I.L.Y.

    1999-01-01

    In this series of studies the relations between swimming behaviour of fish in general and extreme swimming responses in particular (called fast starts or escape responses) and the structure and ontogeny of the muscle system was investigated. Special attention was paid to relate functional

  19. Swimming dynamics of bidirectional artificial flagella

    NARCIS (Netherlands)

    Namdeo, S.; Khaderi, S. N.; Onck, P. R.

    2013-01-01

    We study magnetic artificial flagella whose swimming speed and direction can be controlled using light and magnetic field as external triggers. The dependence of the swimming velocity on the system parameters (e. g., length, stiffness, fluid viscosity, and magnetic field) is explored using a

  20. Evolución del grado de implantación de programas de autocontrol en las piscinas de temporada en Araba/Álava Evolution of the implementation level of self-monitoring programmes for outdoor swimming pools in Araba/Álava Evolução do grau de implementação de programas de autocontrolo em piscinas sazonais em Araba/Álava

    Directory of Open Access Journals (Sweden)

    Arantza Armentia Álvarez

    2012-12-01

    Full Text Available El objetivo principal de este estudio ha sido realizar una valoración de la evolución del grado de implantación de programas de autocontrol en las piscinas descubiertas de Araba/Álava durante seis años (2006-2011. Para ello, en las inspecciones se cumplimentaron protocolos de comprobación basados en instrucciones técnicas, elaboradas para aunar criterios y valorar los diferentes planes del Programa de autocontrol (Estos planes son: 1. Tratamiento y vigilancia del agua; 2. Análisis del agua; 3. Limpieza y desinfección; 4. Seguridad, buenas prácticas e información al usuario; 5. Revisión y mantenimiento; 6. Control de plagas; 7. Proveedores, productos y servicios. Además, se usó una valoración consensuada de cada plan, con el fin de valorar objetivamente las instalaciones y la implantación del autocontrol.The main aim of this study was to carry out an assessment of the implementation level of the self-monitoring programme for outdoor swimming pools in Araba/Álava over a six-year period (2006-2011. For this purpose, inspections were carried out using checklists based on technical guidelines designed to unify criteria and assess the different plans within each self-monitoring programme, including the following: 1. Water Treatment and Monitoring; 2. Water analysis; 3. Cleansing and Disinfection; 4. Safety, Best Practices and User information; 5. Inspection and Maintenance; 6. Pest control; 7. Suppliers, Products and Services. Consensus-based assessments of each plan were also used to objectively evaluate the facilities and the level of implementation of the self-monitoring programme.Este estudo teve como objectivo principal realizar uma avaliação da evolução do grau de implementação de programas de auto controlo nas piscinas descobertas de Álava durante um período de seis anos (2006-2011. Nesse sentido, foram realizadas inspeções técnicas respeitando protocolos assentes em listas de verificação, destinados a unificar

  1. Numerical modelling of methanol liquid pool fires

    Science.gov (United States)

    Prasad, Kuldeep; Li, Chiping; Kailasanath, K.; Ndubizu, Chuka; Ananth, Ramagopal; Tatem, P. A.

    1999-12-01

    The focus of this paper is on numerical modelling of methanol liquid pool fires. A mathematical model is first developed to describe the evaporation and burning of a two-dimensional or axisymmetric pool containing pure liquid methanol. Then, the complete set of unsteady, compressible Navier-Stokes equations for reactive flows are solved in the gas phase to describe the convection of the fuel gases away from the pool surface, diffusion of the gases into the surrounding air and the oxidation of the fuel into product species. Heat transfer into the liquid pool and the metal container through conduction, convection and radiation are modelled by solving a modified form of the energy equation. Clausius-Clapeyron relationships are invoked to model the evaporation rate of a two-dimensional pool of pure liquid methanol. The governing equations along with appropriate boundary and interface conditions are solved using the flux-corrected transport algorithm. Numerical results exhibit a flame structure that compares well with experimental observations. Temperature profiles and burning rates were found to compare favourably with experimental data from single- and three-compartment laboratory burners. The model predicts a puffing frequency of approximately 12 Hz for a 1 cm diameter methanol pool in the absence of any air co-flow. It is also observed that increasing the air co-flow velocity helps in stabilizing the diffusion flame, by pushing the vortical structures away from the flame region.

  2. Prey capture by freely swimming flagellates

    Science.gov (United States)

    Andersen, Anders; Dolger, Julia; Nielsen, Lasse Tor; Kiorboe, Thomas

    2017-11-01

    Flagellates are unicellular microswimmers that propel themselves using one or several beating flagella. Here, we explore the dependence of swimming kinematics and prey clearance rate on flagellar arrangement and determine optimal flagellar arrangements and essential trade-offs. To describe near-cell flows around freely swimming flagellates we consider a model in which the cell is represented by a no-slip sphere and each flagellum by a point force. For uniflagellates pulled by a single flagellum the model suggests that a long flagellum favors fast swimming, whereas high clearance rate is favored by a very short flagellum. For biflagellates with both a longitudinal and a transversal flagellum we explore the helical swimming kinematics and the prey capture sites. We compare our predictions with observations of swimming kinematics, prey capture, and flows around common marine flagellates. The Centre for Ocean Life is a VKR Centre of Excellence supported by the Villum Foundation.

  3. Energetics of swimming of schooling fish

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2012-01-01

    Soc for experimental Biol Annual Meeting - Salzburg 2012 John F. Steffensen (University of Copenhagen, Denmark) When a fish school swims through the water, every individual consumes a certain amount of oxygen, which means that less will be available for the trailing fish in the school. In 1967 Mc......Farland and Moss reported that the oxygen saturation decreased approximately 30% from the front to the rear of an approximately 150-m long school of mullets swimming in normoxic water. They also observed that the decline in oxygen saturation at the rear resulted in the school disintegrating into smaller separate...... schools. Oxygen consumption of swimming fish increases exponentially or as a power function with respect to swimming speed, and hence the decrease in oxygen saturation through the school is related to the swimming speed of the school. A model describing the oxygen saturation in a fish school from front...

  4. Heat exchanger

    International Nuclear Information System (INIS)

    Leigh, D.G.

    1976-01-01

    The arrangement described relates particularly to heat exchangers for use in fast reactor power plants, in which heat is extracted from the reactor core by primary liquid metal coolant and is then transferred to secondary liquid metal coolant by means of intermediate heat exchangers. One of the main requirements of such a system, if used in a pool type fast reactor, is that the pressure drop on the primary coolant side must be kept to a minimum consistent with the maintenance of a limited dynamic head in the pool vessel. The intermediate heat exchanger must also be compact enough to be accommodated in the reactor vessel, and the heat exchanger tubes must be available for inspection and the detection and plugging of leaks. If, however, the heat exchanger is located outside the reactor vessel, as in the case of a loop system reactor, a higher pressure drop on the primary coolant side is acceptable, and space restriction is less severe. An object of the arrangement described is to provide a method of heat exchange and a heat exchanger to meet these problems. A further object is to provide a method that ensures that excessive temperature variations are not imposed on welded tube joints by sudden changes in the primary coolant flow path. Full constructional details are given. (U.K.)

  5. Welding pool measurement using thermal array sensor

    Science.gov (United States)

    Cho, Chia-Hung; Hsieh, Yi-Chen; Chen, Hsin-Yi

    2015-08-01

    Selective laser melting (SLM) is an additive manufacturing (AM) technology that uses a high-power laser beam to melt metal powder in chamber of inert gas. The process starts by slicing the 3D CAD data as a digital information source into layers to create a 2D image of each layer. Melting pool was formed by using laser irradiation on metal powders which then solidified to consolidated structure. In a selective laser melting process, the variation of melt pool affects the yield of a printed three-dimensional product. For three dimensional parts, the border conditions of the conductive heat transport have a very large influence on the melt pool dimensions. Therefore, melting pool is an important behavior that affects the final quality of the 3D object. To meet the temperature and geometry of the melting pool for monitoring in additive manufacturing technology. In this paper, we proposed the temperature sensing system which is composed of infrared photodiode, high speed camera, band-pass filter, dichroic beam splitter and focus lens. Since the infrared photodiode and high speed camera look at the process through the 2D galvanometer scanner and f-theta lens, the temperature sensing system can be used to observe the melting pool at any time, regardless of the movement of the laser spot. In order to obtain a wide temperature detecting range, 500 °C to 2500 °C, the radiation from the melting pool to be measured is filtered into a plurality of radiation portions, and since the intensity ratio distribution of the radiation portions is calculated by using black-body radiation. The experimental result shows that the system is suitable for melting pool to measure temperature.

  6. Pool water cleaning facility

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Kazuhiro; Kinoshita, Shoichiro [Hitachi Ltd., Tokyo (Japan); Asano, Takashi

    1998-05-29

    Only one system comprising a suppression poor water cleaning system (SPCU) and a filtration desalting tower (F/D) is connected for a plurality of nuclear power plants. Pipelines/valves for connecting the one system of the SPCU pump, the F/D and the plurality of nuclear power plants are disposed, and the system is used in common with the plurality of nuclear power plants. Pipelines/valves for connecting a pipeline for passing SP water to the commonly used SPCU pump and a skimmer surge tank are disposed, and fuel pool water is cooled and cleaned by the commonly used SPCU pump and the commonly used F/D. The number of SPCU pumps and the F/D facilities can be reduced, and a fuel pool water cooling operation mode and a fuel pool water cleaning operation mode which were conducted by an FPC pump so far are conducted by the SPCU pump. (N.H.)

  7. Swimming of the Honey Bees

    Science.gov (United States)

    Roh, Chris; Gharib, Morteza

    2016-11-01

    When the weather gets hot, nursing honey bees nudge foragers to collect water for thermoregulation of their hive. While on their mission to collect water, foragers sometimes get trapped on the water surface, forced to interact with a different fluid environment. In this study, we present the survival strategy of the honey bees at the air-water interface. A high-speed videography and shadowgraph were used to record the honey bees swimming. A unique thrust mechanism through rapid vibration of their wings at 60 to 150 Hz was observed. This material is based upon work supported by the National Science Foundation under Grant No. CBET-1511414; additional support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469.

  8. The critical velocity in swimming.

    Science.gov (United States)

    di Prampero, Pietro E; Dekerle, Jeanne; Capelli, Carlo; Zamparo, Paola

    2008-01-01

    In supra-maximal exercise to exhaustion, the critical velocity (cv) is conventionally calculated from the slope of the distance (d) versus time (t) relationship: d = I + St. I is assumed to be the distance covered at the expense of the anaerobic capacity, S the speed maintained on the basis of the subject's maximal O(2) uptake (VO2max) This approach is based on two assumptions: (1) the energy cost of locomotion per unit distance (C) is constant and (2) VO2max is attained at the onset of exercise. Here we show that cv and the anaerobic distance (d (anaer)) can be calculated also in swimming, where C increases with the velocity, provided that VO2max its on-response, and the C versus v relationship are known. d (anaer) and cv were calculated from published data on maximal swims for the four strokes over 45.7, 91.4 and 182.9 m, on 20 elite male swimmers (18.9 +/- 0.9 years, 75.9 +/- 6.4 kg), whose VO2max and C versus speed relationship were determined, and compared to I and S obtained from the conventional approach. cv was lower than S (4, 16, 7 and 11% in butterfly, backstroke, breaststroke and front crawl) and I (=11.6 m on average in the four strokes) was lower than d (anaer). The latter increased with the distance: average, for all strokes: 38.1, 60.6 and 81.3 m over 45.7, 91.4 and 182.9 m. It is concluded that the d versus t relationship should be utilised with some caution when evaluating performance in swimmers.

  9. Body roll in swimming: a review.

    Science.gov (United States)

    Psycharakis, Stelios G; Sanders, Ross H

    2010-02-01

    In this article, we present a critical review of the swimming literature on body roll, for the purposes of summarizing and highlighting existing knowledge, identifying the gaps and limitations, and stimulating further research. The main research findings can be summarized as follows: swimmers roll their shoulders significantly more than their hips; swimmers increase hip roll but maintain shoulder roll when fatigued; faster swimmers roll their shoulders less than slower swimmers during a 200-m swim; roll asymmetries, temporal differences in shoulder roll and hip roll, and shoulder roll side dominance exist in front crawl swimming, but there is no evidence to suggest that they affect swimming performance; and buoyancy contributes strongly to generating body roll in front crawl swimming. Based on and stimulated by current knowledge, future research should focus on the following areas: calculation of body roll for female swimmers and for backstroke swimming; differences in body roll between breathing and non-breathing cycles; causes of body roll asymmetries and their relation to motor laterality; body roll analysis across a wide range of velocities and swimming distances; exploration of the association between body roll and the magnitude and direction of propulsive/resistive forces developed during the stroke cycle; and the influence of kicking actions on the generation of body roll.

  10. Krill (Meganyctiphanes norvegica) swim faster at night

    KAUST Repository

    Klevjer, Thor A.

    2011-05-01

    Krill are key members in marine food webs, and measurement of swimming speed is vital to assess their bioenergetic budgets, feeding, and encounters with predators. We document a consistent and marked diel signal in swimming speed of krill in their natural habitat that is not related to diel vertical migration. The results were obtained using a bottom-mounted, upward-looking echo sounder at 150-m depth in the Oslofjord, Norway, spanning 5 months from late autumn to spring at a temporal resolution of ~1–2 records s−1. Swimming speed was assessed using acoustic target tracking of individual krill. At the start of the registration period, both daytime and nocturnal average swimming speeds of Meganyctiphanes norvegica were ~ 3.5 cm s−1 (~ 1 body lengths ([bl] s−1) in waters with oxygen concentrations of ~ 15–20% O2 saturation. Following intrusion of more oxygenated water, nocturnal average swimming speeds increased to ~ 10 cm s−1 (~ 3 bl s−1), i.e., more than double that of daytime swimming speeds in the same period. We hypothesize that krill activity during the first period was limited by oxygen, and the enhanced swimming at night subsequent to the water renewal is due to increased feeding activity under lessened danger of predation in darkness.

  11. The Effects of Leg Kick on Swimming Speed and Arm-Stroke Efficiency in the Front Crawl.

    Science.gov (United States)

    Silveira, Ricardo Peterson; de Souza Castro, Flávio Antônio; Figueiredo, Pedro; Vilas-Boas, João Paulo; Zamparo, Paola

    2017-07-01

    To analyze the effects of swimming pace on the relative contribution of leg kick to swimming speed and to compare arm-stroke efficiency (ηF) assessed when swimming with the arms only (SAO) and while swimming front crawl (FCS) using individual and fixed adjustments to arm-stroke and leg-kick contribution to forward speed. Twenty-nine master swimmers (21 men, 8 women) performed SAO and FCS at 6 self-selected speeds from very slow to maximal. The average swimming speed (v), stroke frequency (SF), and stroke length (SL) were assessed in the central 10 m of the swimming pool. Then, a 2nd-order polynomial regression was used to obtain values of v at paired SF. The percentage difference in v between FCS and SAO, for each paired SF, was used to calculate the relative contributions of the arm stroke (AC) and leg kick (LC) to FCS. Then ηF was calculated using the indirect "paddle-wheel" approach in 3 different ways: using general, individual, and no adjustments to AC. The LC increased with SF (and speed) from -1% ± 4% to 11% ± 1% (P arm stroke and leg kick should be individually estimated to reduce errors when calculating arm-stroke efficiency at different speeds and in different swimmers.

  12. SWIM EVERYDAY TO KEEP DEMENTIA AWAY

    Directory of Open Access Journals (Sweden)

    Nirmal Singh

    2005-03-01

    Full Text Available A sound mind resides in a sound body. Many individuals with an active lifestyle show sharp mental skills at an advanced age. Regular exercise has been shown to exert numerous beneficial effects on brawn as well as brain. The present study was undertaken to evaluate the influence of swimming on memory of rodents. A specially designed hexagonal water maze was used for the swimming exposures of animals. The learning and memory parameters were measured using exteroceptive behavioral models such as Elevated plus-maze, Hebb-Williams maze and Passive avoidance apparatus. The rodents (rats and mice were divided into twelve groups. The swimming exposure to the rodents was for 10- minute period during each session and there were two swimming exposures on each day. Rats and mice were subjected to swimming for -15 and -30 consecutive days. Control group animals were not subjected to swimming during above period. The learning index and memory score of all the animals was recorded on 1st, 2nd, 15th, 16th, 30th and 31st day employing above exteroceptive models. It was observed that rodents that underwent swimming regularly for 30- days showed sharp memories, when tested on above behavioral models whereas, control group animals showed decline in memory scores. Those animals, which underwent swimming for 15- days only showed good memory on 16th day, which however, declined after 30-days. These results emphasize the role of regular physical exercise particularly swimming in the maintenance and promotion of brain functions. The underlying physiological mechanism for improvement of memory appears to be the result of enhanced neurogenesis.

  13. Liquid sodium pool fires

    International Nuclear Information System (INIS)

    Casselman, C.

    1979-01-01

    Experimental sodium pool combustion results have led to a definition of the combustion kinetics, and have revealed the hazards of sodium-concrete contact reactions and the possible ignition of organic matter (paint) by hydration of sodium peroxide aerosols. Analysis of these test results shows that the controlling mechanism is sodium evaporation diffusion. (author)

  14. Crust formation and its effect on the molten pool coolability

    Energy Technology Data Exchange (ETDEWEB)

    Park, R.J.; Lee, S.J.; Sim, S.K. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-09-01

    Experimental and analytical studies of the crust formation and its effect on the molten pool coolability have been performed to examine the crust formation process as a function of boundary temperatures as well as to investigate heat transfer characteristics between molten pool and overlying water in order to evaluate coolability of the molten pool. The experimental test results have shown that the surface temperature of the bottom plate is a dominant parameter in the crust formation process of the molten pool. It is also found that the crust thickness of the case with direct coolant injection into the molten pool is greater than that of the case with a heat exchanger. Increasing mass flow rate of direct coolant injection to the molten pool does not affect the temperature of molten pool after the crust has been formed in the molten pool because the crust behaves as a thermal barrier. The Nusselt number between the molten pool and the coolant of the case with no crust formation is greater than that of the case with crust formation. The results of FLOW-3D analyses have shown that the temperature distribution contributes to the crust formation process due to Rayleigh-Benard natural convection flow.

  15. Suppression Pool Mixing and Condensation Tests in PUMA Facility

    International Nuclear Information System (INIS)

    Ling Cheng; Kyoung Suk Woo; Mamoru Ishii; Jaehyok Lim; Han, James

    2006-01-01

    Condensation of steam with non-condensable in the form of jet flow or bubbly flow inside the suppression pool is an important phenomenon on determining the containment pressure of a passively safe boiling water reactor. 32 cases of pool mixing and condensation test have been performed in Purdue University Multi-Dimensional Integral Test Assembly (PUMA) facility under the sponsor of the U.S. Nuclear Regulatory Commission to investigate thermal stratification and pool mixing inside the suppression pool during the reactor blowdown period. The test boundary conditions, such as the steam flow rate, the noncondensable gas flow rate, the initial water temperature, the pool initial pressure and the vent opening submergence depth, which covers a wide range of prototype (SBWR-600) conditions during Loss of Coolant Accident (LOCA) were obtained from the RELAP5 calculation. The test results show that steam is quickly condensed at the exit of the vent opening. For pure steam injection or low noncondensable injection cases, only the portion above the vent opening in the suppression pool is heated up by buoyant plumes. The water below the vent opening can be heated up slowly through conduction. The test results also show that the degree of thermal stratification in suppression pool is affected by the vent opening submergence depth, the pool initial pressure and the steam injection rate. And it is slightly affected by the initial water temperature. From these tests it is concluded that the pool mixing is strongly affected by the noncondensable gas flow rate. (authors)

  16. Suncatcher and cool pool. Project report

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, J.

    1981-03-01

    The Suncatcher is a simple, conical solar concentrating device that captures light entering clerestory windows and directs it onto thermal storage elements at the back of a south facing living space. The cone shape and inclination are designed to capture low angle winter sunlight and to reflect away higher angle summer sunlight. It is found that winter radiation through a Suncatcher window is 40 to 50% higher than through an ordinary window, and that the average solar fraction is 59%. Water-filled steal culvert pipes used for thermal storage are found to undergo less stratification, and thus to be more effective, when located where sunlight strikes the bottom rather than the top. Five Suncatcher buildings are described. Designs are considered for 32/sup 0/, 40/sup 0/ and 48/sup 0/ north latitude, and as the latitude increases, the inclination angle of the cone should be lowered. The Cool Pool is an evaporating, shaded roof pond which thermosiphons cool water into water-filled columns within a building. Preliminary experiments indicate that the best shade design has unimpeded north sky view, good ventilation, complete summer shading, a low architectural profile, and low cost attic vent lowers work. Another series of experiments established the satisfactory performance of the Cool Pool on a test building using four water-filled cylinders, two cylinders, and two cylinders connected to the Cool Pool through a heat exchanger. Although an unshaded pool cools better at night than a shaded one, daytime heat gain far offsets this advantage. A vinyl waterbag heat exchanger was developed for use with the Cool Pool. (LEW)

  17. A Review of Swimming Cues and Tips for Physical Education

    Science.gov (United States)

    Higginson, Kelsey; Barney, David

    2016-01-01

    Swimming is a low-impact activity that causes little stress on joints so it can be done for a lifetime. Many teachers may wish to teach swimming but do not have cues or ideas for doing so. This article reviews swimming cues, relays and equipment that can help a physical education teacher include a swimming unit in their curriculum. Certification…

  18. Swimming without a spine: Computational modeling and analysis of the swimming hydrodynamics of the Spanish Dancer.

    Science.gov (United States)

    Zhou, Zhuoyu; Mittal, Rajat

    2017-10-16

    Incompressible flow simulations are used to study the swimming of a Spanish Dancer (Hexabranchus sanguineus), a soft-bodied invertebrate marine gastropod that swims by combining body pitching with undulations of its large mantle. A simple model based on a field video is employed as the basis for the model and coupling of the flow with the body acceleration enables us to examine the free swimming of this animal. Simulations indicate propulsive efficiencies of up to about 57% and terminal swimming speeds of 1.33 body lengths per cycle. Examination of the effect of body planform on the swimming hydrodynamics suggests that the planform of this animal is likely adapted to enhance its swimming performance. © 2017 IOP Publishing Ltd.

  19. THE EFFECTS OF CREATINE LONG-TERM SUPPLEMENTATION ON MUSCLE MORPHOLOGY AND SWIMMING PERFORMANCE IN RATS

    Directory of Open Access Journals (Sweden)

    Sena Erdal

    2009-12-01

    Full Text Available Creatine (Cr has been shown to increase the total muscle mass. The purpose of this study was to investigate the effect of Cr supplementation on muscle morphology and swimming performance, using an animal model. Each rat was subjected to exercise 15-minute period daily for the 12 weeks. The rats were randomly divided into four groups: no Cr supplementation (CON, no Cr supplementation and incomplete food intake (lacking lysine and methionine in diet for rats (INCO, Cr supplementation 1 g·kg-1·day-1 (CREAT-I and Cr supplementation 2 g·kg-1·day-1 (CREAT-II. Three months later, all groups adult rats exercised in swimming pool chambers. Swimming time was recorded as minute for each rat. Following swimming performance period, the animals were killed by cervical dislocation and the gastrocnemius and diaphragm muscles were dissected. Serial slices of 5-7 μm were allocated paraffin wax and histochemical staining procedure of cross-sections was carried out with heamatoxylin-eosin technics. All groups gained body weight at the end of 12 weeks but there was no statistical difference among them. Swimming time values were statistical difference between CREAT-II and CON group as well as between CREAT-I and CON group (p < 0.05. In the INCO group was determined increased connective tissue cell of the muscle sample. In contrast, in the CREAT-I and CREAT-II group, the basic histological changes were large-scale muscle fibers and hypertrophic muscle cells. These results suggest that long-term creatine supplementation increased the number of muscle fibers and enhanced endurance swimming performance in rats

  20. Swimming championship finalist positions on success in international swimming competitions.

    Science.gov (United States)

    Yustres, I; Martín, R; Fernández, L; González-Ravé, J M

    2017-01-01

    The primary goal was to determine whether the achievement of finalist positions in the Junior Championship was associated with the achievement of success in the International Swimming Federation (FINA) World Championship (WC). Secondary goals included analyzing the effect of various factors (gender, age, country, etc) on swimmers' performances. Data were obtained from FINA information about the finalists from 2007 to 2015 WCs and finalists from 2006 to 2013 Junior-WCs (2400 entries). Final filtered database just included swimmers who participated in both junior and senior WCs (719 entries). A univariate general linear model (GLM) was used to examine the association between time; origin (swimmer who participated in Junior WC or not); maintenance years (number of years achieving finalist positions); country; and age, adjusting for year of competition. An ordinal logistic regression (OLR) model was used to identify predictors of achieving the top positions. The origin variable was not significant in either the GLM or the OLR. The only significant variables in the GLM were maintenance years (F4,706 = 7.689; p getting better positions as you get more WCs (odds = 1.85). In conclusion, no evidence was obtained to conclude finalist position in Junior WC have influence in achieve success in FINA WC. Maintenance years in WCs have a positive impact to achieve better positions.

  1. Swimming championship finalist positions on success in international swimming competitions.

    Directory of Open Access Journals (Sweden)

    I Yustres

    Full Text Available The primary goal was to determine whether the achievement of finalist positions in the Junior Championship was associated with the achievement of success in the International Swimming Federation (FINA World Championship (WC. Secondary goals included analyzing the effect of various factors (gender, age, country, etc on swimmers' performances. Data were obtained from FINA information about the finalists from 2007 to 2015 WCs and finalists from 2006 to 2013 Junior-WCs (2400 entries. Final filtered database just included swimmers who participated in both junior and senior WCs (719 entries. A univariate general linear model (GLM was used to examine the association between time; origin (swimmer who participated in Junior WC or not; maintenance years (number of years achieving finalist positions; country; and age, adjusting for year of competition. An ordinal logistic regression (OLR model was used to identify predictors of achieving the top positions. The origin variable was not significant in either the GLM or the OLR. The only significant variables in the GLM were maintenance years (F4,706 = 7.689; p < .05 and year of competition (F4,706 = 23.239; p < .05. The OLR revealed a strong association (p < .001 between the position variable and maintenance years, getting better positions as you get more WCs (odds = 1.85. In conclusion, no evidence was obtained to conclude finalist position in Junior WC have influence in achieve success in FINA WC. Maintenance years in WCs have a positive impact to achieve better positions.

  2. Pool boiling visualization on open microchannel surfaces

    Directory of Open Access Journals (Sweden)

    Kaniowski Robert

    2017-01-01

    Full Text Available The paper presents visualization investigations into pool boiling heat transfer for open minichannel surfaces. The experiments were carried out wih saturated water at atmospheric pressure. Parallel microchannels fabricated by machining were about 0.3 mm wide and 0.2 to 0.4 mm deep. High-speed videos were used as an aid to understanding the heat transfer mechanism. The visualization study aimed at identifying nucleation sites of the departing bubbles and determining their diameters and frequency at various superheats.

  3. Heat transfer and phenomenology in severe accidents in spent fuel pools with MAAP5; Transmision de calor y fenomenologia en accidentes severes en piscinas de combustible gastado con MAAP5

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, J. A.; Gil, E.; Uruburu, A.; Rey, P.

    2013-07-01

    The code Thermo-hydraulic MAAP5 includes in their latest versions a module that allows you to analyze the evolution of an accident occurring in the pool of spent fuel from a nuclear power plant in their latest versions. This module is a preliminary version and there is interest from stations and reference centres in Spain to know in depth its capabilities.

  4. Swimming of Paramecium in confined channels

    Science.gov (United States)

    Jung, Sunghwan

    2012-02-01

    Many living organisms in nature have developed a few different swimming modes, presumably derived from hydrodynamic advantage. Paramecium is a ciliated protozoan covered by thousands of cilia with a few nanometers in diameter and tens of micro-meters in length and is able to exhibit both ballistic and meandering motions. First, we characterize ballistic swimming behaviors of ciliated microorganisms in glass capillaries of different diameters and explain the trajectories they trace out. We develop a theoretical model of an undulating sheet with a pressure gradient and discuss how it affects the swimming speed. Secondly, investigation into meandering swimmings within rectangular PDMS channels of dimension smaller than Paramecium length. We find that Paramecium executes a body-bend (an elastic buckling) using the cilia while it meanders. By considering an elastic beam model, we estimate and show the universal profile of forces it exerts on the walls. Finally, we discuss a few other locomotion of Paramecium in other extreme environments like gel.

  5. Muscle dynamics in fish during steady swimming

    DEFF Research Database (Denmark)

    Shadwick, RE; Steffensen, JF; Katz, SL

    1998-01-01

    SYNOPSIS. Recent research in fish locomotion has been dominated by an interest in the dynamic mechanical properties of the swimming musculature. Prior observations have indicated that waves of muscle activation travel along the body of an undulating fish faster than the resulting waves of muscular...... position in swimming fish. Quantification of muscle contractile properties in cyclic contractions relies on in vitro experiments using strain and activation data collected in vivo. In this paper we discuss the relation between these parameters and body kinematics. Using videoradiographic data from swimming...... constant cross-section of red muscle along much of the body suggests that positive power for swimming is generated fairly uniformly along the length of the fish....

  6. Pool gateway seal

    International Nuclear Information System (INIS)

    Starr, J.A.; Steinert, L.A.

    1983-01-01

    A device for sealing a gateway between interconnectable pools in a nuclear facility comprising a frame supporting a liquid impermeable sheet positioned in a u-shaped gateway between the pools. An inflatable tube carried in a channel in the periphery of the frame and adjoining the gateway provides a seal therebetween when inflated. A restraining arrangement on the bottom edge of the frame is releasably engagable with an adjacent portion of the gateway to restrict the movement of the frame in the u-shaped gateway upon inflation of the tube, thereby enhancing the seal. The impermeable sheet is formed of an elastomer and thus is conformable to a liquid permeable supportive wall upon application of liquid pressure to the side of the sheet opposite the wall

  7. CERN Electronics Pool presentations

    CERN Multimedia

    2011-01-01

    The CERN Electronics Pool has organised a series of presentations in collaboration with oscilloscope manufacturers. The last one will take place according to the schedule below.   Time will be available at the end of the presentation to discuss your personal needs. The Agilent presentation had to be postponed and will be organised later. -     Lecroy: Thursday, 24 November 2011, in 530-R-030, 14:00 to 16:30.

  8. A Single-Unit Design Structure and Gender Differences in the Swimming World Championships

    Directory of Open Access Journals (Sweden)

    Pushkar Svetlana

    2014-10-01

    Full Text Available Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed. An unpaired t-test was used. The p-values were evaluated using Neo-Fisherian significance assessments (Hurlbert and Lombardi, 2012. For the freestyle, gender differences in the start reaction times were positively identified for five of the six SWCs. For the backstroke, gender differences in the start reaction times could be dismissed for five of the six SWCs. For both the butterfly and breaststroke, gender differences in the start reaction times yielded inconsistent statistical differences. Pooling all swimmers together (df = 286 showed that an overall gender difference in the start reaction times could be positively identified: p = 0.00004. The contrast between the gender differences in start reaction times between the freestyle and backstroke may be associated with different types of gender adaptations to swimming performances. When the natural groupings of swimming stroke final events were ignored, sacrificial pseudoreplication occurred, which may lead to erroneous statistical differences

  9. A single-unit design structure and gender differences in the swimming world championships.

    Science.gov (United States)

    Pushkar, Svetlana; Issurin, Vladimir B; Verbitsky, Oleg

    2014-09-29

    Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs) can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed. An unpaired t-test was used. The p-values were evaluated using Neo-Fisherian significance assessments (Hurlbert and Lombardi, 2012). For the freestyle, gender differences in the start reaction times were positively identified for five of the six SWCs. For the backstroke, gender differences in the start reaction times could be dismissed for five of the six SWCs. For both the butterfly and breaststroke, gender differences in the start reaction times yielded inconsistent statistical differences. Pooling all swimmers together (df = 286) showed that an overall gender difference in the start reaction times could be positively identified: p = 0.00004. The contrast between the gender differences in start reaction times between the freestyle and backstroke may be associated with different types of gender adaptations to swimming performances. When the natural groupings of swimming stroke final events were ignored, sacrificial pseudoreplication occurred, which may lead to erroneous statistical differences.

  10. Measurement of hydrodynamic force generation by swimming dolphins using bubble DPIV.

    Science.gov (United States)

    Fish, Frank E; Legac, Paul; Williams, Terrie M; Wei, Timothy

    2014-01-15

    Attempts to measure the propulsive forces produced by swimming dolphins have been limited. Previous uses of computational hydrodynamic models and gliding experiments have provided estimates of thrust production by dolphins, but these were indirect tests that relied on various assumptions. The thrust produced by two actively swimming bottlenose dolphins (Tursiops truncatus) was directly measured using digital particle image velocimetry (DPIV). For dolphins swimming in a large outdoor pool, the DPIV method used illuminated microbubbles that were generated in a narrow sheet from a finely porous hose and a compressed air source. The movement of the bubbles was tracked with a high-speed video camera. Dolphins swam at speeds of 0.7 to 3.4 m s(-1) within the bubble sheet oriented along the midsagittal plane of the animal. The wake of the dolphin was visualized as the microbubbles were displaced because of the action of the propulsive flukes and jet flow. The oscillations of the dolphin flukes were shown to generate strong vortices in the wake. Thrust production was measured from the vortex strength through the Kutta-Joukowski theorem of aerodynamics. The dolphins generated up to 700 N during small amplitude swimming and up to 1468 N during large amplitude starts. The results of this study demonstrated that bubble DPIV can be used effectively to measure the thrust produced by large-bodied dolphins.

  11. Refrigeration. Heat Transfer. Part I: Evaporators and Condensers

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation.......The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation....

  12. Front Crawl Swimming Performance and Bi-Lateral Force Asymmetry during Land-Based and Tethered Swimming Tests

    OpenAIRE

    dos Santos, Karini B.; Bento, Paulo C. Barauce; Pereira, Gleber; Payton, Carl; Rodacki, André L.F.

    2017-01-01

    The aims of this study were to investigate whether land-based and tethered swimming strength tests can explain swimming performance in 200-meter front crawl and, whether these tests were able to identify bilateral symmetry in force production. In the first session, eighteen swimmers completed a maximum effort 200 m front crawl swim (swimming performance) and 15 seconds maximal effort tethered front crawl swim. In the second session, participants performed the upper extremity isometric strengt...

  13. Evaluating Warm-Up Strategies for Elite Sprint Breaststroke Swimming Performance.

    Science.gov (United States)

    McGowan, Courtney J; Pyne, David B; Thompson, Kevin G; Rattray, Ben

    2016-10-01

    Targeted passive heating and completion of dryland-based activation exercises within the warm-up can enhance sprint freestyle performance. The authors investigated if these interventions would also elicit improvements in sprint breaststroke swimming performance. Ten national and internationally competitive swimmers (~805 FINA (Fédération internationale de natation) 2014 scoring points; 6 men, mean ± SD 20 ± 1 y; 4 women, 21 ± 3 y) completed a standardized pool warm-up (1550 m) followed by a 30-min transition phase and a 100-m breaststroke time trial. In the transition phase, swimmers wore a conventional tracksuit and remained seated (control) or wore tracksuit pants with integrated heating elements and performed a 5-min dryland-based exercise routine (combo) in a crossover design. Performance in the 100-m time trial (control: 68.6 ± 4.0 s, combo: 68.4 ± 3.9 s, P = .55) and start times to 15 m (control: 7.3 ± 0.6 s; combo: 7.3 ± 0.6 s; P = .81) were not different between conditions. It was unclear (P = .36) whether combo (-0.12°C ± 0.19°C [mean ± 90% confidence limits]) elicited an improvement in core temperature maintenance in the transition phase compared with control (-0.31°C ± 0.19°C). Skin temperature immediately before commencement of the time trial was higher (by ~1°C, P = .01) within combo (30.13°C ± 0.88°C [mean ± SD]) compared with control (29.11°C ± 1.20°C). Lower-body power output was not different between conditions before the time trial. Targeted passive heating and completion of dryland-based activation exercises in the transition phase does not enhance sprint breaststroke performance despite eliciting elevated skin temperature immediately before time trial commencement.

  14. Klamath County YMCA geothermal heating project environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    Shreve, J.H. (ed.)

    1979-07-10

    The YMCA Geothermal Heating project proposes to obtain approximately 57% of the total facility energy usage through direct application of the Klamath Falls KGRA. This will be accomplished through the design and construction of a retrofit and injection system for the utilization of an existing 110/sup 0/F geothermal energy source at the project site. The existing 2016 foot well will be outfitted with a turbine pump with variable speed drive. The well head will be enclosed by a 10' x 10' building. The geothermal fluid, pumped at a peak rate of 350 gpm will be transported to the YMCA Facility through 5'' diameter schedule 40 black iron pipe fitted with victaulic couplings for expansion. All underground supply pipes will be equipped with magnesium anodes for galvaic protection and will be insulted with 1'' thick calcium silicate insulation, with two layers of 45 number roofing felt applied with asphaltic compound. All supply lines within the building will be insulated with 1'' fiberglass insulation material with a cloth jacket. The fluids will pass through a heating coil and heat exchanger system to provide heat for the 30,000 square foot YMCA facility as well as for the 90,000 gallon swimming pool. The spent geothermal fluids will then be conveyed through a 4'' black iron return pipe to be returned to an acceptable aquifer through the 1500 foot injection well.

  15. Determination of Force Coresponding to Maximal Lactate Steady State in Tethered Swimming.

    Science.gov (United States)

    Papoti, Marcelo; Vitório, Ricardo; Araújo, Gustavo G; DA Silva, Adelino S R; Santhiago, Vanessa; Martins, Luiz E B; Cunha, Sérgio A; Gobatto, Claudio A

    The main aim of the present investigation was to verify if the aerobic capacity (AC) measured in tethered swimming corresponds to the maximal lactate steady state (MLSS) and its correlation with 30 min and 400m free style swimming. Twenty-five swimmers were submitted to an incremental tethered swimming test (ITS) with an initial load of 20N and increments of 10N each 3min. After each stage of 3min, the athletes had 30s of interval to blood sample collections that were used to measure blood lactate concentrations ([La - ]). The AC BI was determined by the abrupt increase in [La - ] versus force (F). The points obtained between [La - ] versus force (N) were adjusted by an exponential curve model to determine AC corresponding to 3.5mmol.l -1 (AC 3.5 ) and 4.0mmol.l -1 (AC 4.0 ). After these procedures, the swimmers performed maximal efforts of 30min and 400m in free style swimming. We used the distance performed in 30min and the time performed in 400m to calculate the median velocities (i.e. V30 and V400) of these protocols. After one week, in order to measure the MLSS, nine athletes performed three 30-min tethered swimming efforts with intensities of 90, 100, and 110% of AC BI . The ANOVA one-way was used to compare the AC BI , AC 3.5 and AC 4.0 . Correlations between ACs, and between ACs and V30 and V400 (p0.91) and V400 (r>0.63). According to our results, it is possible to conclude that the AC BI corresponds to the MLSS, and both the AC - individually determined - and the AC - determined using fixed blood lactate concentrations of 3.5 and 4.0mmol.l -1 - can be used to predict the mean velocity of 30min and 400m in free style swimming. In addition to that, the tethered swimming system can be used for aerobic development in places where official sized swimming pools are not available, such as rehabilitation clinics and health clubs.

  16. Investigation of pool thermal hydraulics and temperature distribution in inner vessel under mechanical seal leakage

    International Nuclear Information System (INIS)

    Abraham, Juby; Velusamy, K.; Selvaraj, P.

    2015-01-01

    The primary heat sink of prototype fast breeder reactor is a sodium pool which is partitioned into cold pool and hot pool. The inner vessel which separates the cold and hot pools is having penetrations for intermediate heat exchangers. The hot sodium from hot pool leaks into the cold pool through these penetrations and to reduce the leakage, mechanical seals are provided. Leakage of hot sodium into cold pool can lead to thermal stratification in the cold pool and also will affect the temperature distribution in inner vessel. 3-D CFD studies were performed focusing these features as a function of sodium leakage. The analyses indicate that the maximum temperature difference across the IV thickness is 65°C without any leakage of sodium. The temperature difference is found to decrease with increase in leakage through the seals. It is seen that a leakage of 2.5% is acceptable. (author)

  17. COLPEX - Cold Pool Experiment

    Science.gov (United States)

    Wells, H.; Price, J.; Horlacher, V.; Sheridan, P. F.; Vosper, S. B.; Brown, A. R.; Mobbs, S. D.; Ross, A. N.

    2009-04-01

    Planning has started towards designing a new field campaign aimed at studying the behaviour of the boundary layer over complex terrain. Of specific interest is the formation of cold-pools in valleys during stable night-time conditions. The field campaign will run continuously until the end of the winter in 2009/10. The experiment will make use of a wide variety of ground-based sensors including turbulence towers, automatic weather stations, Doppler lidar, radiation sensors and soil temperature probes. We also hope to deploy an instrumented car and a tethered balloon facility for limited periods. Data from the field campaign will be used for a number of purposes. Firstly, to increase our understanding of how the valley cold pools form and why, for instance, some valleys offer a more favourable environment for their formation than others. Secondly, to investigate the formation and dissipation of fog in complex terrain. Thirdly, the data set will also be used to help validate and develop the Met Office Unified Model at high resolution. An area for the experiment has been identified in the Shropshire/Powis area of the UK where a network of valleys and low hills exist with a typical valley width of ~1.5km and hill top to valley floor heights of 75-200m. 0m.

  18. Intermittent Swimming with a Flexible Propulsor

    Science.gov (United States)

    Akoz, Emre; Moored, Keith

    2017-11-01

    Aquatic animals use a variety of swimming gaits to propel themselves efficiently through the oceans. One type of gait known as intermittent or burst-and-coast swimming is used by species such as saithe, cod and trout. Recent studies have shown that this gait can save up to 60% of a swimmer's energy by exploiting an inviscid Garrick mechanism. These detailed studies have examined the effects of an intermittent swimming gait on rigid propulsors, yet the caudal fins of intermittent swimmers are in fact highly flexible propulsors. In this respect, to gain a comprehensive understanding of intermittent swimming, the effect of elasticity on the swimming performance and wake flow of an intermittent swimmer is investigated. To accomplish this a torsional spring structural model is strongly coupled to a fast boundary element method solver that captures the fluid-structure interaction of a two-dimensional self-propelled intermittently pitching hydrofoil. It is shown that flexibility introduces extra vortices to the coasting phase of motion that can either promote or diminish thrust production depending upon the hydrofoil parameters. An optimal intermittent flexible swimmer is shown to increase its efficiency by as much as 28% when compared to an optimal continuous flexible swimmer. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI Grant Number N00014-14-1-0533.

  19. Propulsive force asymmetry during tethered-swimming.

    Science.gov (United States)

    dos Santos, K B; Pereira, G; Papoti, M; Bento, P C B; Rodacki, A

    2013-07-01

    This study aimed to determine whether: i) tethe-red-swimming can be used to identify the asymmetry during front crawl swimming style; ii) swimmers that perform unilateral breathing present greater asymmetry in comparison to others that use bilateral breathing; iii) swimmers of best performance present smaller asymmetry than their counterparts; iv) repeated front crawl swimming movements influence body asymmetry. 18 swimmers were assessed for propulsive force parameters (peak force, mean force, impulse and rate of force development) during a maximal front crawl tethered-swimming test lasting 2 min. A factorial analysis showed that propulsive forces decreased at the beginning, intermediate and end of the test (pforce parameters (p>0.05). When performance was considered (below or above mean group time), a larger asymmetry was found in the sub-group of lower performance in comparison to those of best performance (pforces can be detected using tethered-swimming. The propulsive forces decreased during the test but asymmetries did not change under testing conditions. Although breathing preference did not influence asymmetry, swimmers with best performance were less asymmetric than their counterparts. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Analysis of a molten pool natural convection in the APR1400 RPV at a severe accident

    International Nuclear Information System (INIS)

    Kim, Jong Tae; Park, Rae Joon; Kim, Sang Baik

    2005-01-01

    During a hypothetical severe accident, reactor fuel rods and structures supporting them are melted and relocated in the lower head of the reactor vessel. These relocated molten materials could be separated by their density difference and construct metal/oxide stratified pools in the lower head. A decay heat generated from the fuel material is transferred to the vessel wall and upper structures remaining in the reactor vessel by natural convection. As shown in Fig. 1 two-layered stratified molten pool is developed in the reactor lower vessel. The oxidic pool usually constructed by the mixture of uranium oxide and zirconium oxide. The melting temperature of the oxidic material is very high compared to the steel vessel and metallic layer. And highly turbulent natural convection generated by the decay heat enhances heat transfer to the boundary of the oxidic pool. By this thermal mechanism, oxide curst is developed around the oxidic layer as shown in Fig. 1. The oxidic pool is bounded thermally and fluid-dynamically by the developed crust. By this boundedness, the heat transfer structure in the stratified oxidic/metallic pool can be solved separately. The thermal boundary condition of the oxidic pool is isothermal with constant melting temperature of the oxidic material. The decay heat is transfer to side wall and upper interface between oxidic and metallic layer. Turbulent natural convection is dominant heat transfer mechanism in the oxidic pool. The heat transferred from the bottom oxidic layer is imposed to the upper metallic layer. This transferred heat in the metallic pool is removed through side and upper surface, which is augmented also by natural convection developed in the pool. In this study, a molten pool natural convection in the APR1400 RPV during a severe accident is simulated using the Lilac code and the calculated heat flux distribution on the reactor vessel wall is compared with a lumped-parameter (LP) prediction

  1. Simulation and transient analyses of a complete passive heat removal system in a downward cooling pool-type material testing reactor against a complete station blackout and long-term natural convection mode using the RELAP5/3.2 code

    Energy Technology Data Exchange (ETDEWEB)

    Hedayat, Afshin [Reactor and Nuclear Safety School, Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of)

    2017-08-15

    In this paper, a complete station blackout (SBO) or complete loss of electrical power supplies is simulated and analyzed in a downward cooling 5-MW pool-type Material Testing Reactor (MTR). The scenario is traced in the absence of active cooling systems and operators. The code nodalization is successfully benchmarked against experimental data of the reactor's operating parameters. The passive heat removal system includes downward water cooling after pump breakdown by the force of gravity (where the coolant streams down to the unfilled portion of the holdup tank), safety flapper opening, flow reversal from a downward to an upward cooling direction, and then the upward free convection heat removal throughout the flapper safety valve, lower plenum, and fuel assemblies. Both short-term and long-term natural core cooling conditions are simulated and investigated using the RELAP5 code. Short-term analyses focus on the safety flapper valve operation and flow reversal mode. Long-term analyses include simulation of both complete SBO and long-term operation of the free convection mode. Results are promising for pool-type MTRs because this allows operators to investigate RELAP code abilities for MTR thermal–hydraulic simulations without any oscillation; moreover, the Tehran Research Reactor is conservatively safe against the complete SBO and long-term free convection operation.

  2. Simulation and transient analyses of a complete passive heat removal system in a downward cooling pool-type material testing reactor against a complete station blackout and long-term natural convection mode using the RELAP5/3.2 code

    Directory of Open Access Journals (Sweden)

    Afshin Hedayat

    2017-08-01

    Full Text Available In this paper, a complete station blackout (SBO or complete loss of electrical power supplies is simulated and analyzed in a downward cooling 5-MW pool-type Material Testing Reactor (MTR. The scenario is traced in the absence of active cooling systems and operators. The code nodalization is successfully benchmarked against experimental data of the reactor's operating parameters. The passive heat removal system includes downward water cooling after pump breakdown by the force of gravity (where the coolant streams down to the unfilled portion of the holdup tank, safety flapper opening, flow reversal from a downward to an upward cooling direction, and then the upward free convection heat removal throughout the flapper safety valve, lower plenum, and fuel assemblies. Both short-term and long-term natural core cooling conditions are simulated and investigated using the RELAP5 code. Short-term analyses focus on the safety flapper valve operation and flow reversal mode. Long-term analyses include simulation of both complete SBO and long-term operation of the free convection mode. Results are promising for pool-type MTRs because this allows operators to investigate RELAP code abilities for MTR thermal–hydraulic simulations without any oscillation; moreover, the Tehran Research Reactor is conservatively safe against the complete SBO and long-term free convection operation.

  3. Estimation of reactor pool water temperature after shutdown in JRR-3M

    International Nuclear Information System (INIS)

    Yagi, Masahiro; Sato, Mitsugu; Kakefuda, Kazuhiro

    1999-01-01

    The reactor pool water temperature increasing by the decay heat was estimated by calculation. The reactor pool water temperature was calculated by increased enthalpy that was estimated by the reactor decay heat, the heat released from the reactor biological shielding concrete, reactor pool water surface, the heat conduction from the canal and the core inlet piping. These results of calculation were compared with the past measured data. As the results of estimation, after the JRR-3M shutdown, the calculated reactor pool temperature first increased sharply. This is because the decay heat was the major contribution. And then, rate of increased reactor pool temperature decreased. This is because the ratio of heat released from reactor biological shielding concrete and core inlet piping to the decay heat increased. Besides, the calculated reactor pool water temperature agreed with the past measured data in consequence of correcting the decay heat and the released heat. The corrected coefficient k 1 of decay heat was 0.74 - 0.80. And the corrected coefficient k 2 of heat released from the reactor biological shielding concrete was 3.5 - 4.5. (author)

  4. PHYSIOLOGICAL, BIOMECHANICAL AND ANTHROPOMETRICAL PREDICTORS OF SPRINT SWIMMING PERFORMANCE IN ADOLESCENT SWIMMERS

    Directory of Open Access Journals (Sweden)

    Evelin Lätt

    2010-09-01

    Full Text Available The purpose of this study was to analyze the relationships between 100-m front crawl swimming performance and relevant biomechanical, anthropometrical and physiological parameters in male adolescent swimmers. Twenty five male swimmers (mean ± SD: age 15. 2 ± 1.9 years; height 1.76 ± 0.09 m; body mass 63.3 ± 10.9 kg performed an all-out 100-m front crawl swimming test in a 25-m pool. A respiratory snorkel and valve system with low hydrodynamic resistance was used to collect expired air. Oxygen uptake was measured breath-by-breath by a portable metabolic cart. Swimming velocity, stroke rate (SR, stroke length and stroke index (SI were assessed during the test by time video analysis. Blood samples for lactate measurement were taken from the fingertip pre exercise and at the third and fifth minute of recovery to estimate net blood lactate accumulation (?La. The energy cost of swimming was estimated from oxygen uptake and blood lactate energy equivalent values. Basic anthropometry included body height, body mass and arm span. Body composition parameters were measured using dual-energy X-ray absorptiometry (DXA. Results indicate that biomechanical factors (90.3% explained most of 100-m front crawl swimming performance variability in these adolescent male swimmers, followed by anthropometrical (45.8% and physiological (45.2% parameters. SI was the best single predictor of performance, while arm span and ∆La were the best anthropometrical and physiological indicators, respectively. SI and SR alone explained 92.6% of the variance in competitive performance. These results confirm the importance of considering specific stroke technical parameters when predicting success in young swimmers.

  5. SWIMMING BEHAVIOR OF DEVELOPMENTAL STAGES OF THE CALANOID COPEPOD TEMORA-LONGICORNIS AT DIFFERENT FOOD CONCENTRATIONS

    NARCIS (Netherlands)

    VANDUREN, LA; VIDELER, JJ

    1995-01-01

    The swimming behaviour of developmental stages of the marine calanoid copepod Temora longicornis was studied using 2-dimensional observations under a microscope and a 3-dimensional filming technique to analyze swimming mode, swimming speed and swimming trajectories under different food

  6. Swimming type inspection device and system thereof

    International Nuclear Information System (INIS)

    Ito, Arata; Kimura, Motohiko; Ito, Tomoyuki

    1998-01-01

    The present invention provides a swimming type inspection device which can be reduced in the size, easily accessible to each portion of a reactor, and increase the degree of freedom of swimming and visual range, and facilitate visual inspection. The swimming type inspection device comprises two photographing devices, a device which can obtain propelling force by rotation of impellers, two second propelling devices having impellers disposed in perpendicular to the rotating axis of the impellers of the first propelling device, a control device for controlling control signals of first and second propelling devices and driving devices therefor and control image signals of the photographing devices, and transmission section for wireless transmitting of the control signals and the image signals. (N.H.)

  7. Swimming and feeding of mixotrophic biflagellates

    DEFF Research Database (Denmark)

    Dölger, Julia; Nielsen, Lasse Tor; Kiørboe, Thomas

    2017-01-01

    with variable position next to a no-slip sphere. Utilizing the observations and the model we find that puller force arrangements favour feeding, whereas equatorial force arrangements favour fast and quiet swimming. We determine the capture rates of both passive and motile prey, and we show that the flow......Many unicellular flagellates are mixotrophic and access resources through both photosynthesis and prey capture. Their fitness depends on those processes as well as on swimming and predator avoidance. How does the flagellar arrangement and beat pattern of the flagellate affect swimming speed......, predation risk due to flow-sensing predators, and prey capture? Here, we describe measured flows around two species of mixotrophic, biflagellated haptophytes with qualitatively different flagellar arrangements and beat patterns. We model the near cell flows using two symmetrically arranged point forces...

  8. Quiet swimming at low Reynolds number

    DEFF Research Database (Denmark)

    Andersen, Anders Peter; Wadhwa, Navish; Kiørboe, Thomas

    2015-01-01

    The stresslet provides a simple model of the flow created by a small, freely swimming and neutrally buoyant aquatic organism and shows that the far field fluid disturbance created by such an organism in general decays as one over distance squared. Here we discuss a quieter swimming mode...... that eliminates the stresslet component of the flow and leads to a faster spatial decay of the fluid disturbance described by a force quadrupole that decays as one over distance cubed. Motivated by recent experimental results on fluid disturbances due to small aquatic organisms, we demonstrate that a three......-Stokeslet model of a swimming organism which uses breast stroke type kinematics is an example of such a quiet swimmer. We show that the fluid disturbance in both the near field and the far field is significantly reduced by appropriately arranging the propulsion apparatus, and we find that the far field power laws...

  9. Swimming economy: determinant factors and assessment issues

    Directory of Open Access Journals (Sweden)

    Giovanni Novaes

    2006-09-01

    Full Text Available Swimming economy is an important parameter in the control of the training process, since it has been demonstrated that this concept is related to the swimming performance. Swimming economy is affected by physiological and biomechanical constraints, therefore being a concept that reflects the swimmers´ adaptation to the liquid environment in those two domains. A review of the literature about swimming economy is presented, focusing some of the most relevant studies that have been conducted on this issue. Other than the biomechanical and physiological constraints, the swimming economy is influenced by other factors such as: swimming velocity, technical ability, training status, gender, age and anthropometric characteristics. Therefore a multitude of aspects are pertinent in the assessment of swimming economy and in the application of this concept in the control of the swimmers’ training process. A proper assessment of the swimming economy requires the direct measurement of the oxygen uptake. The choice of the protocol to assess the swimming economy must be carefully done. Particular attention must be paid to the oxygen uptake kinetics across the different levels of exercise intensity. Therefore, both exercise intensity and duration are to be considered. The attainment of swimming velocities as close as possible to the competition velocity is also an important issue. Although few studies have measured directly the oxygen uptake of top-level performers during swimming, the literature shows that a discontinuous protocol, with increasing exercise bouts of duration between three and six minutes seem appropriate to assess the swimming economy. RESUMO Economia de nado é um parâmetro importante no controle do processo de treinamento, desde que foi demonstrado que este conceito é relacionado ao desempenho de nado. Economia de nado é afetada por aspectosfisiológicos e biomecânicos, sendo então um conceito que reflete a adaptação de nadadores ao

  10. Analysis of swimming performance: perceptions and practices of US-based swimming coaches.

    Science.gov (United States)

    Mooney, Robert; Corley, Gavin; Godfrey, Alan; Osborough, Conor; Newell, John; Quinlan, Leo Richard; ÓLaighin, Gearóid

    2016-01-01

    In elite swimming, a broad range of methods are used to assess performance, inform coaching practices and monitor athletic progression. The aim of this paper was to examine the performance analysis practices of swimming coaches and to explore the reasons behind the decisions that coaches take when analysing performance. Survey data were analysed from 298 Level 3 competitive swimming coaches (245 male, 53 female) based in the United States. Results were compiled to provide a generalised picture of practices and perceptions and to examine key emerging themes. It was found that a disparity exists between the importance swim coaches place on biomechanical analysis of swimming performance and the types of analyses that are actually conducted. Video-based methods are most frequently employed, with over 70% of coaches using these methods at least monthly, with analyses being mainly qualitative in nature rather than quantitative. Barriers to the more widespread use of quantitative biomechanical analysis in elite swimming environments were explored. Constraints include time, cost and availability of resources, but other factors such as sources of information on swimming performance and analysis and control over service provision are also discussed, with particular emphasis on video-based methods and emerging sensor-based technologies.

  11. Propulsive efficiency of frog swimming with different feet and swimming patterns.

    Science.gov (United States)

    Jizhuang, Fan; Wei, Zhang; Bowen, Yuan; Gangfeng, Liu

    2017-04-15

    Aquatic and terrestrial animals have different swimming performances and mechanical efficiencies based on their different swimming methods. To explore propulsion in swimming frogs, this study calculated mechanical efficiencies based on data describing aquatic and terrestrial webbed-foot shapes and swimming patterns. First, a simplified frog model and dynamic equation were established, and hydrodynamic forces on the foot were computed according to computational fluid dynamic calculations. Then, a two-link mechanism was used to stand in for the diverse and complicated hind legs found in different frog species, in order to simplify the input work calculation. Joint torques were derived based on the virtual work principle to compute the efficiency of foot propulsion. Finally, two feet and swimming patterns were combined to compute propulsive efficiency. The aquatic frog demonstrated a propulsive efficiency (43.11%) between those of drag-based and lift-based propulsions, while the terrestrial frog efficiency (29.58%) fell within the range of drag-based propulsion. The results illustrate the main factor of swimming patterns for swimming performance and efficiency. © 2017. Published by The Company of Biologists Ltd.

  12. Propulsive efficiency of frog swimming with different feet and swimming patterns

    Directory of Open Access Journals (Sweden)

    Fan Jizhuang

    2017-04-01

    Full Text Available Aquatic and terrestrial animals have different swimming performances and mechanical efficiencies based on their different swimming methods. To explore propulsion in swimming frogs, this study calculated mechanical efficiencies based on data describing aquatic and terrestrial webbed-foot shapes and swimming patterns. First, a simplified frog model and dynamic equation were established, and hydrodynamic forces on the foot were computed according to computational fluid dynamic calculations. Then, a two-link mechanism was used to stand in for the diverse and complicated hind legs found in different frog species, in order to simplify the input work calculation. Joint torques were derived based on the virtual work principle to compute the efficiency of foot propulsion. Finally, two feet and swimming patterns were combined to compute propulsive efficiency. The aquatic frog demonstrated a propulsive efficiency (43.11% between those of drag-based and lift-based propulsions, while the terrestrial frog efficiency (29.58% fell within the range of drag-based propulsion. The results illustrate the main factor of swimming patterns for swimming performance and efficiency.

  13. Determination of a quantitative parameter to evaluate swimming technique based on the maximal tethered swimming test.

    Science.gov (United States)

    Soncin, Rafael; Mezêncio, Bruno; Ferreira, Jacielle Carolina; Rodrigues, Sara Andrade; Huebner, Rudolf; Serrão, Julio Cerca; Szmuchrowski, Leszek

    2017-06-01

    The aim of this study was to propose a new force parameter, associated with swimmers' technique and performance. Twelve swimmers performed five repetitions of 25 m sprint crawl and a tethered swimming test with maximal effort. The parameters calculated were: the mean swimming velocity for crawl sprint, the mean propulsive force of the tethered swimming test as well as an oscillation parameter calculated from force fluctuation. The oscillation parameter evaluates the force variation around the mean force during the tethered test as a measure of swimming technique. Two parameters showed significant correlations with swimming velocity: the mean force during the tethered swimming (r = 0.85) and the product of the mean force square root and the oscillation (r = 0.86). However, the intercept coefficient was significantly different from zero only for the mean force, suggesting that although the correlation coefficient of the parameters was similar, part of the mean velocity magnitude that was not associated with the mean force was associated with the product of the mean force square root and the oscillation. Thus, force fluctuation during tethered swimming can be used as a quantitative index of swimmers' technique.

  14. Preliminary Calculation on a Spent Fuel Pool Accident using GOTHIC

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jaehwan; Choi, Yu Jung; Hong, Tae Hyub; Kim, Hyeong-Taek [KHNP-CRI, Daejeon (Korea, Republic of)

    2015-10-15

    The probability of an accident happening at the spent fuel pool was believed to be quite low until the 2011 Fukushima accident occurred. Notably, large amount of spent fuel are normally stored in the spent fuel pool for a long time compared to the amount of fuel in the reactor core and the total heat released from the spent fuel is high enough to boil the water of the spent fuel pool when the cooling system does not operate. In addition, the enrichment and the burnup of the fuel have both increased in the past decade and heat generation from the spent fuel thereby has also increased. The failure of the cooling system at the spent fuel pool (hereafter, a loss-of-cooling accident) is one of the principal hypothetical causes of an accident that could occur at the spent fuel pool. In this paper, the preliminary calculation of a loss-of-cooling accident was performed. In this paper, the preliminary calculation of a loss-of cooling accident was performed with GOTHIC. The calculation results show boiling away of water in the spent fuel pool due to the loss-of-cooling accident and similar thermal performance of the spent fuel pool with previous research results.

  15. Paramecium swimming in a capillary tube

    Science.gov (United States)

    Jana, Saikat; Jung, Sunghwan

    2010-03-01

    Micro-organisms exhibit different strategies for swimming in complex environments. Many micro-swimmers such as paramecium congregate and tend to live near wall. We investigate how paramecium moves in a confined space as compared to its motion in an unbounded fluid. A new theoretical model based on Taylor's sheet is developed, to study such boundary effects. In experiments, paramecia are put inside capillary tubes and their swimming behavior is observed. The data obtained from experiments is used to test the validity of our theoretical model and understand how the cilia influence the locomotion of paramecia in confined geometries.

  16. Estimating energy expenditure during front crawl swimming using accelerometers

    DEFF Research Database (Denmark)

    Nordsborg, Nikolai Baastrup; Espinosa, Hugo G.; Van Thiel, David H

    2014-01-01

    The determination of energy expenditure is of major interest in training load and performance assessment. Small, wireless accelerometer units have the potential to characterise energy expenditure during swimming. The correlation between absorbed oxygen versus flume swimming speed and absorbed...

  17. Front Crawl Swimming Performance and Bi-Lateral Force Asymmetry during Land-Based and Tethered Swimming Tests

    Directory of Open Access Journals (Sweden)

    Karini B. dos Santos, Paulo C. Barauce Bento, Gleber Pereira, Carl Payton, André L.F. Rodacki

    2017-12-01

    Full Text Available The aims of this study were to investigate whether land-based and tethered swimming strength tests can explain swimming performance in 200-meter front crawl and, whether these tests were able to identify bilateral symmetry in force production. In the first session, eighteen swimmers completed a maximum effort 200 m front crawl swim (swimming performance and 15 seconds maximal effort tethered front crawl swim. In the second session, participants performed the upper extremity isometric strength test. Peak force production of tethered swimming and isometric strength tests were significantly correlated for the strongest and weakest sides (r = 0.58 and r = 0.63, respectively; p < 0.05, but only peak force production during tethered swimming correlated with 200 m swimming performance time (r = -0.55, p < 0.05. Bilateral asymmetries in peak force and rate of force development were similar between the tethered swimming and isometric strength tests (peak force: 13%, p = 0.24; rate of force development: 15%, p = 0.88 However, both tests detected significant difference of peak force and rate of force development between body sides. The tethered swimming test can partially explain the 200 m front crawl swimming performance. In addition, the land-based and tethered swimming tests may be used to identify bilateral asymmetry of swimming

  18. Front Crawl Swimming Performance and Bi-Lateral Force Asymmetry during Land-Based and Tethered Swimming Tests.

    Science.gov (United States)

    Dos Santos, Karini B; Bento, Paulo C Barauce; Pereira, Gleber; Payton, Carl; Rodacki, André L F

    2017-12-01

    The aims of this study were to investigate whether land-based and tethered swimming strength tests can explain swimming performance in 200-meter front crawl and, whether these tests were able to identify bilateral symmetry in force production. In the first session, eighteen swimmers completed a maximum effort 200 m front crawl swim (swimming performance) and 15 seconds maximal effort tethered front crawl swim. In the second session, participants performed the upper extremity isometric strength test. Peak force production of tethered swimming and isometric strength tests were significantly correlated for the strongest and weakest sides (r = 0.58 and r = 0.63, respectively; p force production during tethered swimming correlated with 200 m swimming performance time (r = -0.55, p force and rate of force development were similar between the tethered swimming and isometric strength tests (peak force: 13%, p = 0.24; rate of force development: 15%, p = 0.88) However, both tests detected significant difference of peak force and rate of force development between body sides. The tethered swimming test can partially explain the 200 m front crawl swimming performance. In addition, the land-based and tethered swimming tests may be used to identify bilateral asymmetry of swimming.

  19. Velocity Fields Measurement of Natural Circulation Flow inside a Pool Using PIV Technique

    International Nuclear Information System (INIS)

    Kim, Seok; Kim, Dong Eok; Youn, Young Jung; Euh, Dong Jin; Song, Chul Hwa

    2012-01-01

    Thermal stratification is encountered in large pool of water increasingly being used as heat sink in new generation of advanced reactors. These large pools at near atmospheric pressure provide a heat sink for heat removal from the reactor or steam generator, and the containment by natural circulation as well as a source of water for core cooling. For examples, the PAFS (passive auxiliary feedwater system) is one of the advanced safety features adopted in the APR+ (Advanced Power Reactor Plus), which is intended to completely replace the conventional active auxiliary feedwater system. The PAFS cools down the steam generator secondary side and eventually removes the decay heat from the reactor core by adopting a natural convection mechanism. In a pool, the heat transfer from the PCHX (passive condensation heat exchanger) contributed to increase the pool temperature up to the saturation condition and induce the natural circulation flow of the PCCT (passive condensate cooling tank) pool water. When a heat rod is placed horizontally in a pool of water, the fluid adjacent to the heat rod gets heated up. In the process, its density reduces and by virtue of the buoyancy force, the fluid in this region moves up. After reaching the top free surface, the heated water moves towards the other side wall of the pool along the free surface. Since this heated water is cooling, it goes downward along the wall at the other side wall. Above heater rod, a natural circulation flow is formed. However, there is no flow below heater rod until pool water temperature increases to saturation temperature. In this study, velocity measurement was conducted to reveal a natural circulation flow structure in a small pool using PIV (particle image velocimetry) measurement technique

  20. A study of some radioprotection apparatuses used in the case of pool reactors

    International Nuclear Information System (INIS)

    Robien, E. de; Choudens, H. de; Delpuech, J.

    1965-01-01

    Various problems of radioprotection concerning swimming-pool reactors in Grenoble have led us to study adequate solutions: a) The automatic verification of the staff-radioactivity when coming out of Melusine or Siloe has been realized thanks to a βγ gate which is insensitive to the ambient background in the reactor-hall; b) The automatic verification of the contamination of the shoes of the agents working in these reactors has been realized with a dedicated device; c) The necessity to measure precisely γ doses with the help of an autonomous apparatus has led to the making of a plastic-scintillator γ dosimeter; d) The obligation to forbid the opening of doors in some places where there might be a great intensity of radiation, has led us to make doors open according to the intensity of radiation inside the rooms; e) The releases of radioactive iodine have been measured with activated charcoal cartridges that surround a scintillator connected with a unique channel selector; f) Finally the control of reactor safety rod fall in case of a radioactive accident has been secured by a chain whose detector is a chamber immersed in the swimming-pool, which offers, in the particular case of the hot thickness swimming-pool reactor a double advantage: first it enables us to regulate the upper hot water layer, second to get free of transitory radiations which appear in the reactor hall as the experimental apparatuses are taken out from the core. (authors) [fr

  1. Use of the Term “Shock” in Swimming Pool, Hot Tubs, and Spa Products

    Science.gov (United States)

    EPA has determined that shock treatment and super-chlorination are terms usually used to describe claims to kill or control visible algae growth. Claims to kill, prevent or control algae or bacteria are pesticide claims.

  2. Fast neutron spectrum in the reflector of swimming pool reactor behind metallics slabs

    International Nuclear Information System (INIS)

    Brousse, J.C.

    1970-01-01

    The large perturbations of fast neutron spectrum were measured behind lead, aluminium and iron slabs in the Siloette reflector at the CENG. The neutron slowing down is chiefly depending of the inelastic reaction. The reaction cross section increases with energy; a spectrum softening is deduced. This is verified. We tried to determine the spectrum shape by calculation to fit the measurements. Calculations were firstly made in unidimensional geometry by the NIOBE transport equation resolution code and by the SANE Monte-Carlo code. The results does not agree with the experimental determined values. Finally a semi-empirical method for studying a tridimensional geometry was chosen. We have obtained calculation results in a perfect agreement with measurements. The method is described. (author) [fr

  3. Experimental study on the impulsive load of follow fuel assembly of swimming pool research reactor

    International Nuclear Information System (INIS)

    Sun Changlong; Bo Hanliang; Jiang Shengyao; Zhang Hongchao; Ma Cang; Wang Jinhua; Qin Benke

    2005-01-01

    Through the data of impulsive load experiment on this fuel assembly, this paper obtained how the impact force and impact acceleration changed with time and other parameters, and analyzed the causation of the different impact force and impact acceleration, further more, found the disciplinarian of impulsive load. Investigation showed: the fuel assembly of electromagnetic movable coil control rod drive mechanism is firm enough to suffer from the impulsive load, so it suits using in the reactor. (authors)

  4. Specifies of teaching swimming to children with autism spectrum disorder

    OpenAIRE

    Baštová, Miroslava

    2017-01-01

    Title: Specifics of teaching swimming to children with autism spectrum disorder. Objectives: Creation and implementation of the concept of preparatory and basic swimming lessons for children with autism spectrum disorder. Evaluation of information on continuing education and the achieved level of swimming skills and swimming locomotion observed in children with autism spectrum disorder. Presentation and qualitative assessment of the four case studies and subsequent design of guidelines for sw...

  5. New construction standard for electrical underfloor and ceiling heatings DIN VDE 0100 part 520 A3. Pt. 2. Neue Errichtungsnorm fuer elektrische Fussboden- und Deckenheizungen DIN VDE 0100 Teil 520 A3. T. 2

    Energy Technology Data Exchange (ETDEWEB)

    Nienhaus, H.

    1991-06-01

    Several standards have to be taken into account for the installation of underfloor and ceiling heating. Mainly DIN 19560 part 1 applies to the laying of heating elements in the floors. Apart from that there are a number of additional requirements for rooms with bath tub or shower, areas of swimming pools, agricultural premises, premises and rooms with high fire risk, exterior areas. It is particularly important to explain structure and function of the underfloor or ceiling heating to the builder-owner and user of the system. Also here the information to be given is laid down in standards. At the end of the article a comprehensive list of all standards and technical regulations concerning this field is given. (BWI). Pt. 1 published in TAB, Tech. Bau (1991) v. 22(5).

  6. Efficacy of a modified tapering protocol on swimming performance ...

    African Journals Online (AJOL)

    Performance assessment following tapering consisted of 2 swims over a distance of 200 m, with a recovery period of 5 hours between swims. After resuming normal ... Total time and split times for each length, stroke rate, distance per stroke, and stroke index in a performance swim were determined as well as heart rate (HR) ...

  7. The fluid dynamics of swimming by jumping in copepods

    DEFF Research Database (Denmark)

    Jiang, Houshuo; Kiørboe, Thomas

    2011-01-01

    Copepods swim either continuously by vibrating their feeding appendages or erratically by repeatedly beating their swimming legs resulting in a series of small jumps. The two swimming modes generate different hydrodynamic disturbances and therefore expose the swimmers differently to rheotactic pr...

  8. Ion-swimming speed variation of Vibrio cholerae cells

    Indian Academy of Sciences (India)

    In the present work we report the variation in swimming speed of Vibrio cholerae with respect to the change in concentration of sodium ions in the medium. We have also studied the variation in swimming speed with respect to temperature. We find that the swimming speed initially shows a linear increase with the increase of ...

  9. Morphology of drying blood pools

    Science.gov (United States)

    Laan, Nick; Smith, Fiona; Nicloux, Celine; Brutin, David; D-Blood project Collaboration

    2016-11-01

    Often blood pools are found on crime scenes providing information concerning the events and sequence of events that took place on the scene. However, there is a lack of knowledge concerning the drying dynamics of blood pools. This study focuses on the drying process of blood pools to determine what relevant information can be obtained for the forensic application. We recorded the drying process of blood pools with a camera and measured the weight. We found that the drying process can be separated into five different: coagulation, gelation, rim desiccation, centre desiccation, and final desiccation. Moreover, we found that the weight of the blood pool diminishes similarly and in a reproducible way for blood pools created in various conditions. In addition, we verify that the size of the blood pools is directly related to its volume and the wettability of the surface. Our study clearly shows that blood pools dry in a reproducible fashion. This preliminary work highlights the difficult task that represents blood pool analysis in forensic investigations, and how internal and external parameters influence its dynamics. We conclude that understanding the drying process dynamics would be advancement in timeline reconstitution of events. ANR funded project: D-Blood Project.

  10. Do all frogs swim alike? The effect of ecological specialization on swimming kinematics in frogs

    Czech Academy of Sciences Publication Activity Database

    Robovská-Havelková, P.; Aerts, P.; Roček, Zbyněk; Přikryl, Tomáš; Fabre, A.-C.; Herrel, A.

    2014-01-01

    Roč. 217, č. 20 (2014), s. 3637-3644 ISSN 0022-0949 Institutional support: RVO:67985831 Keywords : Anura * kinematics * locomotion * swimming Subject RIV: EG - Zoology Impact factor: 2.897, year: 2014

  11. Swimming obstructed by dead-water

    NARCIS (Netherlands)

    Ganzevles, S.P.M; Nuland, F.S.W.; Maas, L.; Toussaint, H.M.

    2009-01-01

    In nautical literature, ‘dead-water’ refers to the obstructive effect encountered by ships moving in stratified water due to the ship generating waves on an interface that separates different water masses. To investigate the hypothesis that open water swimming may also be obstructed by an encounter

  12. Swimming obstructed by dead-water

    NARCIS (Netherlands)

    Ganzevles, S.P.; Nuland, F.S.; Maas, L.R.; Toussaint, H.M.

    2009-01-01

    In nautical literature, 'dead-water' refers to the obstructive effect encountered by ships moving in stratified water due to the ship generating waves on an interface that separates different water masses. To investigate the hypothesis that open water swimming may also be obstructed by an encounter

  13. Surveillance and Conformity in Competitive Youth Swimming

    Science.gov (United States)

    Lang, Melanie

    2010-01-01

    Underpinned by a Foucauldian analysis of sporting practices, this paper identifies the disciplinary mechanism of surveillance at work in competitive youth swimming. It highlights the ways in which swimmers and their coaches are subject to and apply this mechanism to produce embodied conformity to normative behaviour and obedient, docile bodies.…

  14. Healthy Swimming Is a Partnership Effort

    Science.gov (United States)

    Grosse, Susan J.

    2009-01-01

    While one cannot control the water chemistry, he/she can control personal hygiene and facility cleanliness. Giardia and cryptosporidium (crypto) are only two of the many recreational water illnesses (RWIs) that can turn happy swim memories into serious illness situations. In this article, the author discusses three factors that determine how…

  15. Biomechanics of swimming in developing larval fish

    NARCIS (Netherlands)

    Voesenek, Cees J.; Muijres, Florian T.; Leeuwen, Van Johan L.

    2018-01-01

    Most larvae of bony fish are able to swim almost immediately after hatching. Their locomotory system supports several vital functions: fish larvae make fast manoeuvres to escape from predators, aim accurately during suction feeding and maymigrate towards suitable future habitats. Owing to their

  16. Swimming in air-breathing fishes.

    Science.gov (United States)

    Lefevre, S; Domenici, P; McKenzie, D J

    2014-03-01

    Fishes with bimodal respiration differ in the extent of their reliance on air breathing to support aerobic metabolism, which is reflected in their lifestyles and ecologies. Many freshwater species undertake seasonal and reproductive migrations that presumably involve sustained aerobic exercise. In the six species studied to date, aerobic exercise in swim flumes stimulated air-breathing behaviour, and there is evidence that surfacing frequency and oxygen uptake from air show an exponential increase with increasing swimming speed. In some species, this was associated with an increase in the proportion of aerobic metabolism met by aerial respiration, while in others the proportion remained relatively constant. The ecological significance of anaerobic swimming activities, such as sprinting and fast-start manoeuvres during predator-prey interactions, has been little studied in air-breathing fishes. Some species practise air breathing during recovery itself, while others prefer to increase aquatic respiration, possibly to promote branchial ion exchange to restore acid-base balance, and to remain quiescent and avoid being visible to predators. Overall, the diversity of air-breathing fishes is reflected in their swimming physiology as well, and further research is needed to increase the understanding of the differences and the mechanisms through which air breathing is controlled and used during exercise. © 2014 The Fisheries Society of the British Isles.

  17. What Research Tells the Coach About Swimming.

    Science.gov (United States)

    Faulkner, John A.

    This booklet is designed to make research findings about swimming available with interpretations for practical application. Chapter 1, "Physical Characteristics of Swimmers," discusses somatotyping, body composition, and growth. Chapter 2, "Physiological Characteristics of Swimmers," discusses resting rate, vital capacity, effects of water…

  18. Aerobic and anaerobic performances in tethered swimming.

    Science.gov (United States)

    Papoti, M; da Silva, A S R; Araujo, G G; Santiago, V; Martins, L E B; Cunha, S A; Gobatto, C A

    2013-08-01

    The purpose of this study was to investigate whether the critical force (CritF) and anaerobic impulse capacity (AIC) - estimated by tethered swimming - reflect the aerobic and anaerobic performance of swimmers. 12 swimmers performed incremental test in tethered swimming to determine lactate anaerobic threshold (AnTLAC), maximal oxygen uptake ( ˙VO2MAX) and force associated with the ˙VO2MAX (i ˙VO2MAX). The swimmers performed 4 exhaustive (tlim) exercise bouts (100, 110, 120 and 130% i ˙VO2MAX) to compute the CritF and AIC (F vs. 1/tlim model); a 30-s all-out tethered swimming bout to determine their anaerobic fitness (ANF); 100, 200, and 400-m time-trials to determine the swimming performance. CritF (57.09±11.77 N) did not differ from AnTLAC (53.96±11.52 N, (P>0.05) but was significantly lower than i ˙VO2MAX (71.02±8.36 N). In addition, CritF presented significant correlation with AnTLAC (r=0.76; Pswimming. © Georg Thieme Verlag KG Stuttgart · New York.

  19. How do amoebae swim and crawl?

    Directory of Open Access Journals (Sweden)

    Jonathan D Howe

    Full Text Available The surface behaviour of swimming amoebae was followed in cells bearing a cAR1-paGFP (cyclic AMP receptor fused to a photoactivatable-GFP construct. Sensitized amoebae were placed in a buoyant medium where they could swim toward a chemoattractant cAMP source. paGFP, activated at the cell's front, remained fairly stationary in the cell's frame as the cell advanced; the label was not swept rearwards. Similar experiments with chemotaxing cells attached to a substratum gave the same result. Furthermore, if the region around a lateral projection near a crawling cell's front is marked, the projection and the labelled cAR1 behave differently. The label spreads by diffusion but otherwise remains stationary in the cell's frame; the lateral projection moves rearwards on the cell (remaining stationary with respect to the substrate, so that it ends up outside the labelled region. Furthermore, as cAR1-GFP cells move, they occasionally do so in a remarkably straight line; this suggests they do not need to snake to move on a substratum. Previously, we suggested that the surface membrane of a moving amoeba flows from front to rear as part of a polarised membrane trafficking cycle. This could explain how swimming amoebae are able to exert a force against the medium. Our present results indicate that, in amoebae, the suggested surface flow does not exist: this implies that they swim by shape changes.

  20. Swimming of the pea crab (Pinnotheres pisum)

    NARCIS (Netherlands)

    Versteegh, C.P.C.; Muller, M.

    2014-01-01

    Aquatic organisms have to deal with different hydrodynamic regimes, depending on their size and speed during locomotion. The pea crab swims by beating the third and fourth pereiopod on opposite sides as pairs. Using particle tracking velocimetry and high-speed video recording, we quantify the

  1. [Lumbar hypermobility: where swimming becomes hydrotherapy].

    Science.gov (United States)

    Mergeay, D; De Neve, M

    1990-01-01

    In this paper the authors discuss the clinical problem of lumbar hypermobility. The therapeutical possibilities are resumed briefly. The philosophy of medical training therapy ("Heilgymnastik") is described. More extensive the extra-advantages of hydrotherapy (methodical back-stroke swimming) are searched for in a theoretical deductive way. The authors found that: 1. swimming is a low-impact sport so far as the articulations are concerned, 2. back-stroke is done mainly in a lumbar kyphosis, 3. swimming is also an excellent cardiopulmonary training, 4. when swimming the muscles of the shoulder girdle and pelvic girdle are trained in a nearly isokinetic way (power-endurance), 5. the short transverso-spinal muscles are indirectly trained in their tonic more than phasic stretch reflex (posture function), 6. the muscles of the trunk are trained in a nearly isometric way in the appropriate angles (erect position), 7. the position of the head in the water facilitates the abdominal muscles (tonic neck reflex), 8. the cool temperature of the water generates training-enhancing stress-responses, 9. endurance-training is ideal for the postural function of the lower back muscles (especially the deeper layers near the spine) which are anatomical and physiological suited for this purpose, 10. warming-up and cooling-down procedures prepare the neuromuscular, the cardiovascular and metabolic functions before the workout-session (a cold shower afterwards acts to tonicize the skin and muscles).

  2. Sinusoidal cycling swimming pattern of reservoir fishes

    Czech Academy of Sciences Publication Activity Database

    Čech, Martin; Kubečka, Jan

    2002-01-01

    Roč. 61, č. 2 (2002), s. 456-471 ISSN 0022-1112 R&D Projects: GA AV ČR IAA6017901; GA AV ČR IAA6017201; GA ČR GA206/02/0520 Keywords : sinusoidal swimming * echosounder * reservoir Subject RIV: EH - Ecology, Behaviour Impact factor: 1.186, year: 2002

  3. Extreme swimming: The oceanic migrations of anguillids

    DEFF Research Database (Denmark)

    Righton, David; Aarestrup, Kim; Jellyman, Don

    2013-01-01

    to their natal habitat to spawn. In temperate species, the migrations are extreme, requiring larvae and adults to swim thousands of km before reaching their destination, but the migrations of tropical species (hundreds of km) are still remarkable in comparison with many other fish species. To achieve...

  4. Unsteady propulsion by an intermittent swimming gait

    Science.gov (United States)

    Akoz, Emre; Moored, Keith W.

    2018-01-01

    Inviscid computational results are presented on a self-propelled swimmer modeled as a virtual body combined with a two-dimensional hydrofoil pitching intermittently about its leading edge. Lighthill (1971) originally proposed that this burst-and-coast behavior can save fish energy during swimming by taking advantage of the viscous Bone-Lighthill boundary layer thinning mechanism. Here, an additional inviscid Garrick mechanism is discovered that allows swimmers to control the ratio of their added mass thrust-producing forces to their circulatory drag-inducing forces by decreasing their duty cycle, DC, of locomotion. This mechanism can save intermittent swimmers as much as 60% of the energy it takes to swim continuously at the same speed. The inviscid energy savings are shown to increase with increasing amplitude of motion, increase with decreasing Lighthill number, Li, and switch to an energetic cost above continuous swimming for sufficiently low DC. Intermittent swimmers are observed to shed four vortices per cycle that form into groups that are self-similar with the DC. In addition, previous thrust and power scaling laws of continuous self-propelled swimming are further generalized to include intermittent swimming. The key is that by averaging the thrust and power coefficients over only the bursting period then the intermittent problem can be transformed into a continuous one. Furthermore, the intermittent thrust and power scaling relations are extended to predict the mean speed and cost of transport of swimmers. By tuning a few coefficients with a handful of simulations these self-propelled relations can become predictive. In the current study, the mean speed and cost of transport are predicted to within 3% and 18% of their full-scale values by using these relations.

  5. Effect of dielectrophoretic force on swimming bacteria.

    Science.gov (United States)

    Tran, Ngoc Phu; Marcos

    2015-07-01

    Dielectrophoresis (DEP) has been applied widely in bacterial manipulation such as separating, concentrating, and focusing. Previous studies primarily focused on the collective effects of DEP force on the bacterial population. However, the influence of DEP force on the swimming of a single bacterium had not been investigated. In this study, we present a model to analyze the effect of DEP force on a swimming helically flagellated bacterium, particularly on its swimming direction and velocity. We consider a simple DEP force that acts along the X-direction, and its strength as well as direction varies with the X- and Y-positions. Resistive force theory is employed to compute the hydrodynamic force on the bacterium's flagellar bundle, and the effects of both DEP force and rotational diffusion on the swimming of the bacterium are simultaneously taken into consideration using the Fokker-Planck equation. We show the mechanism of how DEP force alters the orientation and velocity of the bacterium. In most cases, the DEP force dominantly influences the orientation of the swimming bacterium; however, when the DEP force strongly varies along the Y-direction, the rotational diffusion is also responsible for determining the bacterium's reorientation. More interestingly, the variance of DEP force along the Y-direction causes the bacterium to experience a translational velocity perpendicular to its primary axis, and this phenomenon could be utilized to focus the bacteria. Finally, we show the feasibility of applying our findings to achieve bacterial focusing. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Microbiological Analysis in Three Diverse Natural Geothermal Bathing Pools in Iceland

    Science.gov (United States)

    Thorolfsdottir, Berglind Osk Th.; Marteinsson, Viggo Thor

    2013-01-01

    Natural thermal bathing pools contain geothermal water that is very popular to bathe in but the water is not sterilized, irradiated or treated in any way. Increasing tourism in Iceland will lead to increasing numbers of bath guests, which can in turn affect the microbial flora in the pools and therefore user safety. Today, there is no legislation that applies to natural geothermal pools in Iceland, as the water is not used for consumption and the pools are not defined as public swimming pools. In this study, we conducted a microbiological analysis on three popular but different natural pools in Iceland, located at Lýsuhóll, Hveravellir and Landmannalaugar. Total bacterial counts were performed by flow cytometry, and with plate count at 22 °C, 37 °C and 50 °C. The presence of viable coliforms, Enterococcus spp. and pseudomonads were investigated by growth experiments on selective media. All samples were screened for noroviruses by real time PCR. The results indicate higher fecal contamination in the geothermal pools where the geothermal water flow was low and bathing guest count was high during the day. The number of cultivated Pseudomonas spp. was high (13,000–40,000 cfu/100 mL) in the natural pools, and several strains were isolated and classified as opportunistic pathogens. Norovirus was not detected in the three pools. DNA was extracted from one-liter samples in each pool and analyzed by partial 16S rRNA gene sequencing. Microbial diversity analysis revealed different microbial communities between the pools and they were primarily composed of alpha-, beta- and gammaproteobacteria. PMID:23493033

  7. The evolution of phenotypic plasticity in fish swimming

    Science.gov (United States)

    Oufiero, Christopher E.; Whitlow, Katrina R.

    2016-01-01

    Abstract Fish have a remarkable amount of variation in their swimming performance, from within species differences to diversity among major taxonomic groups. Fish swimming is a complex, integrative phenotype and has the ability to plastically respond to a myriad of environmental changes. The plasticity of fish swimming has been observed on whole-organismal traits such as burst speed or critical swimming speed, as well as underlying phenotypes such as muscle fiber types, kinematics, cardiovascular system, and neuronal processes. Whether the plastic responses of fish swimming are beneficial seems to depend on the environmental variable that is changing. For example, because of the effects of temperature on biochemical processes, alterations of fish swimming in response to temperature do not seem to be beneficial. In contrast, changes in fish swimming in response to variation in flow may benefit the fish to maintain position in the water column. In this paper, we examine how this plasticity in fish swimming might evolve, focusing on environmental variables that have received the most attention: temperature, habitat, dissolved oxygen, and carbon dioxide variation. Using examples from previous research, we highlight many of the ways fish swimming can plastically respond to environmental variation and discuss potential avenues of future research aimed at understanding how plasticity of fish swimming might evolve. We consider the direct and indirect effects of environmental variation on swimming performance, including changes in swimming kinematics and suborganismal traits thought to predict swimming performance. We also discuss the role of the evolution of plasticity in shaping macroevolutionary patterns of diversity in fish swimming. PMID:29491937

  8. Energetics of median and paired fin swimming, body and caudal fin swimming, and gait transition in parrotfish (Scarus schlegeli) and triggerfish (Rhinecanthus aculeatus)

    DEFF Research Database (Denmark)

    Korsmeyer, Keith E; Steffensen, John Fleng; Herskin, Jannik

    2002-01-01

    To determine the energetic costs of rigid-body, median or paired-fin (MPF) swimming versus undulatory, body-caudal fin (BCF) swimming, we measured oxygen consumption as a function of swimming speed in two MPF swimming specialists, Schlegel's parrotfish and Picasso triggerfish. The parrotfish swam.......1 L s(-1) (30 min U(crit)). In both species, the rates of increase in oxygen consumption with swimming speed were higher during BCF swimming than during rigid-body MPF swimming. Our results indicate that, for these species, undulatory swimming is energetically more costly than rigid-body swimming......, and therefore support the hypothesis that MPF swimming is more efficient. In addition, use of the BCF gait at higher swimming speed increased the cost of transport in both species beyond that predicted for MPF swimming at the same speeds. This suggests that, unlike for terrestrial locomotion, gait transition...

  9. A comprehensive review on pool boiling of nanofluids

    International Nuclear Information System (INIS)

    Ciloglu, Dogan; Bolukbasi, Abdurrahim

    2015-01-01

    Nanofluids are nanoparticle suspensions of small particle size and low concentration dispersed in base fluids such as water, oil and ethylene glycol. These fluids have been considered by researchers as a unique heat transfer carrier because of their thermophysical properties and a great number of potential benefits in traditional thermal engineering applications, including power generation, transportation, air conditioning, electronics devices and cooling systems. Many attempts have been made in the literature on nanofluid boiling; however, data on the boiling heat transfer coefficient (HTC) and the critical heat flux (CHF) have been inconsistent. This paper presents a review of recent researches on the pool boiling heat transfer behaviour of nanofluid. First, the development of nanofluids and their potential applications are briefly given. Then, the effects of various parameters on nanofluids pool boiling are discussed in detail. - Highlights: • A review on the pool boiling heat transfer of nanofluid is presented and discussed. • Nanoparticle deposition considerably affects the boiling heat transfer. • The HTC decreases due to the low contact angle and the high adhesion energy. • The HTC increases due to the formation of the new cavities and liquid suction. • The CHF increases due to the increase in roughness, wettability and capillarity

  10. A Correlational Analysis of Tethered Swimming, Swim Sprint Performance and Dry-land Power Assessments.

    Science.gov (United States)

    Loturco, I; Barbosa, A C; Nocentini, R K; Pereira, L A; Kobal, R; Kitamura, K; Abad, C C C; Figueiredo, P; Nakamura, F Y

    2016-03-01

    Swimmers are often tested on both dry-land and in swimming exercises. The aim of this study was to test the relationships between dry-land, tethered force-time curve parameters and swimming performances in distances up to 200 m. 10 young male high-level swimmers were assessed using the maximal isometric bench-press and quarter-squat, mean propulsive power in jump-squat, squat and countermovement jumps (dry-land assessments), peak force, average force, rate of force development (RFD) and impulse (tethered swimming) and swimming times. Pearson product-moment correlations were calculated among the variables. Peak force and average force were very largely correlated with the 50- and 100-m swimming performances (r=- 0.82 and -0.74, respectively). Average force was very-largely/largely correlated with the 50- and 100-m performances (r=- 0.85 and -0.67, respectively). RFD and impulse were very-largely correlated with the 50-m time (r=- 0.72 and -0.76, respectively). Tethered swimming parameters were largely correlated (r=0.65 to 0.72) with mean propulsive power in jump-squat, squat-jump and countermovement jumps. Finally, mean propulsive power in jump-squat was largely correlated (r=- 0.70) with 50-m performance. Due to the significant correlations between dry-land assessments and tethered/actual swimming, coaches are encouraged to implement strategies able to increase leg power in sprint swimmers. © Georg Thieme Verlag KG Stuttgart · New York.

  11. Numerical simulation of pool boiling of a Lennard-Jones liquid

    KAUST Repository

    Inaoka, Hajime

    2013-09-01

    We performed a numerical simulation of pool boiling by a molecular dynamics model. In the simulation, a liquid composed of Lennard-Jones particles in a uniform gravitational field is heated by a heat source at the bottom of the system. The model successfully reproduces the change in regimes of boiling from nucleate boiling to film boiling with the increase of the heat source temperature. We present the pool boiling curve by the model, whose general behavior is consistent with those observed in experiments of pool boiling. © 2013 Elsevier B.V. All rights reserved.

  12. Melt pool vorticity in deep penetration laser material welding

    Indian Academy of Sciences (India)

    this value, convective heat transfer indicates melting and evaporation occurring in the weld pool during laser ... while surface tension and hydrostatic pressure help to retain the melt in the keyhole cavity in this high .... so does the strength of the shock wave and the Mach angle becomes increasingly narrow. As the melt flow ...

  13. Swimming Dynamics of the Lyme Disease Spirochete

    Science.gov (United States)

    Vig, Dhruv K.; Wolgemuth, Charles W.

    2012-11-01

    The Lyme disease spirochete, Borrelia burgdorferi, swims by undulating its cell body in the form of a traveling flat wave, a process driven by rotating internal flagella. We study B. burgdorferi’s swimming by treating the cell body and flagella as linearly elastic filaments. The dynamics of the cell are then determined from the balance between elastic and resistive forces and moments. We find that planar, traveling waves only exist when the flagella are effectively anchored at both ends of the bacterium and that these traveling flat waves rotate as they undulate. The model predicts how the undulation frequency is related to the torque from the flagellar motors and how the stiffness of the cell body and flagella affect the undulations and morphology.

  14. Addition of fraction in swimming context

    Science.gov (United States)

    Putri, R. I. I.; Gunawan, M. S.; Zulkardi

    2017-12-01

    This study aimed to produce learning trajectory that can help students in learning fractions by using swimming context. The study involved 37 fourth grade students with different capabilities in Elementary School IBA, South Sumatra, Indonesia. This study used an instructional theory called Indonesian version of Realistic Mathematics Education (PMRI). This research used design research method with three stages: preliminary design, the design experiment, and retrospective analysis. Several techniques used for collecting data including a video recording of students interaction in the group discussion, students’ work, and interviewing the students. To conclude, the swimming context could stimulate students’ informal knowledge about the meaning of fractions in which it can be used in the additional learning either the same denominator or different denominator.

  15. Spent fuel storage pool and reactor well pool

    International Nuclear Information System (INIS)

    Fuchisawa, Hiroshi.

    1996-01-01

    An overflow device is disposed to a water draining channel communicating a spent fuel storage pool, a well pool and a cask cleaning pit, and a cleaning treatment system is connected to the cask cleaning pit. In addition, a tank chamber having an overflow device communicating with the well pool is disposed to the inside of the spent fuel storage pool, and a cleaning system is connected to the tank chamber. Namely, water overflow from the spent fuel storage pool and the well pool flows down to the cask cleaning pit directly, the water level can be kept to a predetermined value without disposing a skimmer serge tank, and the overflow water is transported to and cleaned in the cleaning treatment system. In addition, the overflow water flow to the tank chamber directly is transferred to and cleaned in the cleaning treatment system. The cost for the reactor building can be reduced, and interference with the building and adjustment for the steps upon installation of the skimmer serge tank are no more necessary to shorten the terms for the building construction. (N.H.)

  16. Quality versus Quantity Debate in Swimming: Perceptions and Training Practices of Expert Swimming Coaches.

    Science.gov (United States)

    Nugent, Frank J; Comyns, Thomas M; Warrington, Giles D

    2017-06-01

    The debate over low-volume, high-intensity training versus high-volume, low-intensity training, commonly known as Quality versus Quantity, respectively, is a frequent topic of discussion among swimming coaches and academics. The aim of this study was to explore expert coaches' perceptions of quality and quantity coaching philosophies in competitive swimming and to investigate their current training practices. A purposeful sample of 11 expert swimming coaches was recruited for this study. The study was a mixed methods design and involved each coach participating in 1 semi-structured interview and completing 1 closed-ended questionnaire. The main findings of this study were that coaches felt quality training programmes would lead to short term results for youth swimmers, but were in many cases more appropriate for senior swimmers. The coaches suggested that quantity training programmes built an aerobic base for youth swimmers, promoted technical development through a focus on slower swimming and helped to enhance recovery from training or competition. However, the coaches continuously suggested that quantity training programmes must be performed with good technique and they felt this was a misunderstood element. This study was a critical step towards gaining a richer and broader understanding on the debate over Quality versus Quantity training from an expert swimming coaches' perspective which was not currently available in the research literature.

  17. Controlled-frequency breath swimming improves swimming performance and running economy.

    Science.gov (United States)

    Lavin, K M; Guenette, J A; Smoliga, J M; Zavorsky, G S

    2015-02-01

    Respiratory muscle fatigue can negatively impact athletic performance, but swimming has beneficial effects on the respiratory system and may reduce susceptibility to fatigue. Limiting breath frequency during swimming further stresses the respiratory system through hypercapnia and mechanical loading and may lead to appreciable improvements in respiratory muscle strength. This study assessed the effects of controlled-frequency breath (CFB) swimming on pulmonary function. Eighteen subjects (10 men), average (standard deviation) age 25 (6) years, body mass index 24.4 (3.7) kg/m(2), underwent baseline testing to assess pulmonary function, running economy, aerobic capacity, and swimming performance. Subjects were then randomized to either CFB or stroke-matched (SM) condition. Subjects completed 12 training sessions, in which CFB subjects took two breaths per length and SM subjects took seven. Post-training, maximum expiratory pressure improved by 11% (15) for all 18 subjects (P swimming may improve muscular oxygen utilization during terrestrial exercise in novice swimmers. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Quality Versus Quantity Debate in Swimming: Perceptions and Training Practices of Expert Swimming Coaches

    Directory of Open Access Journals (Sweden)

    Nugent Frank J.

    2017-06-01

    Full Text Available The debate over low-volume, high-intensity training versus high-volume, low-intensity training, commonly known as Quality versus Quantity, respectively, is a frequent topic of discussion among swimming coaches and academics. The aim of this study was to explore expert coaches’ perceptions of quality and quantity coaching philosophies in competitive swimming and to investigate their current training practices. A purposeful sample of 11 expert swimming coaches was recruited for this study. The study was a mixed methods design and involved each coach participating in 1 semi-structured interview and completing 1 closed-ended questionnaire. The main findings of this study were that coaches felt quality training programmes would lead to short term results for youth swimmers, but were in many cases more appropriate for senior swimmers. The coaches suggested that quantity training programmes built an aerobic base for youth swimmers, promoted technical development through a focus on slower swimming and helped to enhance recovery from training or competition. However, the coaches continuously suggested that quantity training programmes must be performed with good technique and they felt this was a misunderstood element. This study was a critical step towards gaining a richer and broader understanding on the debate over Quality versus Quantity training from an expert swimming coaches’ perspective which was not currently available in the research literature.

  19. Anaerobic critical velocity in four swimming techniques.

    Science.gov (United States)

    Neiva, H P; Fernandes, R J; Vilas-Boas, J P

    2011-03-01

    The aim of this study was to assess critical velocity in order to control and evaluate anaerobic swimming training. 51 highly trained male swimmers performed maximal 15, 25, 37.5 and 50 m in the 4 swimming techniques to determine critical velocity from the distance-time relationship. Anaerobic critical velocity was compared with 100 m swimming performance and corresponding partials. Complementarily, 9 swimmers performed a 6×50 m (4 min interval) training series at front crawl individual anaerobic critical velocity, capillary blood lactate concentrations being assessed after each repetition. The mean±SD values of anaerobic critical velocity and its relationship with the 100 m event were: 1.61±0.07 (r=0.60, p=0.037), 1.53±0.05 (r=0.81, p=0.015), 1.33±0.05 (r=0.83, p=0.002), and 1.75±0.05 (r=0.74, p=0.001), for butterfly, backstroke, breaststroke and front crawl, respectively. However, differences between anaerobic critical velocity and performance were observed (with exception of the second half of the 100 m swimming events in breaststroke and butterfly). Lactate concentration values at the end of the series were 14.52±1.06 mmol.l (-1), which suggests that it was indeed an anaerobic training set. In this sense, anaerobic critical velocity can be used to prescribe anaerobic training intensities. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Propulsive force symmetry generated during butterfly swimming

    Directory of Open Access Journals (Sweden)

    Gustavo Soares Pereira

    2015-12-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2015v17n6p704   The aim of the study was to analyze the hand force symmetry in butterfly swimming. Fourteen male and female swimmers (18.4 ± 4.9 years old, 71.8 ± 14.6 kg of body mass, 1.78 ± 0.09 m of height and mean performance that corresponds to 74.9 ± 5.8% of the world record. Subjects performed three trials of 25 m of butterfly swimming at maximal speed. Mean and maximum forces were estimated for each hand using pressure sensors of the Aquanex System (Swimming Technology Research, USA. The comparisons between force values for dominant and non-dominant hands were made through Student’s T test for dependent samples (p<0.05. In addition, the symmetry Index (SI was calculated as a relative measure of the force applied by each hand. The mean and maximum force for the dominant hand corresponded, respectively, to 55.7 ± 14.7 N and 114.7 ± 39.6 N. For the non-dominant hand, values were 51.2 ± 14.7 N for mean force and 110.7 ± 36.7 N for maximum force. Significant differences were found between dominant and non-dominant hands for both variables (p<0.01. The symmetry index analysis showed mean values of 8.9% for mean force and of 12.6% for maximum force, and most swimmers presented values higher than 10% for mean and/or maximum forces. Further studies should be performed in order to investigate the relationship between hand force symmetry and swimming performance.