WorldWideScience

Sample records for hydrodynamic cavitation set-up

  1. Effect of hydrodynamic cavitation on zooplankton: A tool for disinfection

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Anil, A.C.; Venkat, K.; Gaonkar, C.; Kolwalkar, J.; Khandeparker, L.; Desai, D.V.; Mahulkar, A.V.; Ranade, V.V.; Pandit, A.B.

    Application of hydrodynamic cavitation for disinfection of water is gaining momentum, as it provides environmentally and economically sound options. In this effort, the effect of cavitating conditions created by differential pump valve opening...

  2. VibroCav: Hydrodynamic Vibration and Cavitation Technology

    NARCIS (Netherlands)

    Bakker, T.W.

    2012-01-01

    Vibration and cavitation can be generated in many ways and serve many useful purposes. This study describes physical aspects of useful vibration and cavitation for a broad spectrum of applications at atmospheric or elevated pressures. After a review of available devices, hydrodynamic vibrating-body

  3. VibroCav: Hydrodynamic Vibration and Cavitation Technology

    NARCIS (Netherlands)

    Bakker, T.W.

    2012-01-01

    Vibration and cavitation can be generated in many ways and serve many useful purposes. This study describes physical aspects of useful vibration and cavitation for a broad spectrum of applications at atmospheric or elevated pressures. After a review of available devices, hydrodynamic vibrating-body

  4. Metal of cavitation erosion of a hydrodynamic reactor

    Science.gov (United States)

    Zakirzakov, A. G.; Brand, A. E.; Petryakov, V. A.; Gordievskaya, E. F.

    2017-02-01

    Cavitation erosion is a major cause of the petroleum equipment hydraulic erosion, which leads to the metal weight loss of the equipment and its breakdown, which can be followed by the full stop of the plant or company work. The probability of the metal weight loss and equipment failure can be reduced by the use of special protective coatings or rivets, made of the sacrificial metals, the use of which significantly increases the service life and the production equipment reliability. The article investigates the cavitation erosion effect, occurred under the condition of the advanced hydrodynamic cavitation on the hydrodynamic cavitation reactor. This article presents the results of the experiments and recommendations for increasing the operational resource.

  5. A novel brewing process via controlled hydrodynamic cavitation

    CERN Document Server

    Albanese, Lorenzo; Meneguzzo, Francesco; Pagliaro, Mario

    2016-01-01

    This paper describes a completely new brewing equipment and process based upon controlled hydrodynamic cavitation, providing significant advantages in terms of lowered capital cost, reduced production time, enhanced energy and production efficiency, food safety, while preserving beer organoleptic qualities. Experiments carried out on real microbrewery volume scale using the new and conventional technology unquestionably confirm the relevance of the new findings. Impacts of these discoveries are potentially far reaching, as beer is the worldwide most widely consumed alcoholic beverage, therefore highly relevant to health, environment the economy and even to local identities.

  6. Intensification of biogas production using pretreatment based on hydrodynamic cavitation.

    Science.gov (United States)

    Patil, Pankaj N; Gogate, Parag R; Csoka, Levente; Dregelyi-Kiss, Agota; Horvath, Miklos

    2016-05-01

    The present work investigates the application of hydrodynamic cavitation (HC) for the pretreatment of wheat straw with an objective of enhancing the biogas production. The hydrodynamic cavitation reactor is based on a stator and rotor assembly. The effect of three different speeds of rotor (2300, 2500, 2700 rpm), wheat straw to water ratios (0.5%, 1% and 1.5% wt/wt) and also treatment times as 2, 4 and 6 min have been investigated in the work using the design of experiments (DOE) approach. It was observed that the methane yield of 31.8 ml was obtained with untreated wheat straw whereas 77.9 ml was obtained with HC pre-treated wheat straw confirming the favourable changes during the pre-treatment. The combined pre-treatment using KOH and HC gave maximum yield of biogas as 172.3 ml. Overall, it has been established that significant enhancement in the biogas production can be obtained due to the pretreatment using HC which can also be further intensified by combination with chemical treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Bulk Viscosity and Cavitation in Boost-Invariant Hydrodynamic Expansion

    CERN Document Server

    Rajagopal, Krishna

    2009-01-01

    We solve second order relativistic hydrodynamics equations for a boost-invariant 1+1-dimensional expanding fluid with an equation of state taken from lattice calculations of the thermodynamics of strongly coupled quark-gluon plasma. We investigate the dependence of the energy density as a function of proper time on the values of the shear viscosity, the bulk viscosity, and second order coefficients, confirming that large changes in the values of the latter have negligible effects. Varying the shear viscosity between zero and a few times s/(4 pi), with s the entropy density, has significant effects, as expected based on other studies. Introducing a nonzero bulk viscosity also has significant effects. In fact, if the bulk viscosity peaks near the crossover temperature Tc to the degree indicated by recent lattice calculations in QCD without quarks, it can make the fluid cavitate -- falling apart into droplets. It is interesting to see a hydrodynamic calculation predicting its own breakdown, via cavitation, at th...

  8. Thermo-Hydrodynamic Analysis of a Plain Journal Bearing on the Basis of a New Mass Conserving Cavitation Algorithm

    NARCIS (Netherlands)

    Alakhramsing, S.; Van Ostayen, R.A.J.; Eling, R.P.T.

    2015-01-01

    Accurate prediction of cavitation is an important feature in hydrodynamic bearing modeling. Especially for thermo-hydrodynamic modeling, it is crucial to use a mass-conservative cavitation algorithm. This paper introduces a new mass-conserving Reynolds cavitation algorithm, which provides fast conve

  9. Effect of geometry of hydrodynamically cavitating device on degradation of orange-G.

    Science.gov (United States)

    Saharan, Virendra Kumar; Rizwani, Manav A; Malani, Aqeel A; Pandit, Aniruddha B

    2013-01-01

    In this research work, we have carried out geometric optimization of different cavitating devices using degradation of orange-G dye [OG] as a model pollutant. Three different cavitating devices viz. orifice plate, circular venturi and slit venturi were optimized and the degradation of orange-G dye was studied. The optimization of all three cavitating devices was done in terms of fluid inlet pressure to the cavitating devices and cavitation number. The effect of pH and initial concentration of the dye on the degradation rate was also studied. The geometry of cavitating device (flow cross sectional area, perimeter, shape, etc.) was found to be an important parameter in getting the maximum cavitational effect using hydrodynamic cavitation. The cavitational yield of all three cavitating devices were compared on the basis of mg of total organic carbon (TOC) reduction per unit energy supplied. The slit venturi gives almost 50% higher degradation rate and cavitational yield among all three cavitating devices studied for the same amount of energy supplied.

  10. Hydrodynamic cavitation in micro channels with channel sizes of 100 and 750 micrometers

    NARCIS (Netherlands)

    Rooze, J.; André, M.; Gulik, van der G-J.S.; Fernandez Rivas, D.; Gardeniers, J.G.E.; Rebrov, E.V.; Schouten, J.C.; Keurentjes, J.T.F.

    2012-01-01

    Decreasing the constriction size and residence time in hydrodynamic cavitation is predicted to give increased hot spot temperatures at bubble collapse and increased radical formation rate. Cavitation in a 100 × 100 μm2 rectangular micro channel and in a circular 750 μm diameter milli channel has be

  11. Enhanced decolorization of methyl orange using zero-valent copper nanoparticles under assistance of hydrodynamic cavitation.

    Science.gov (United States)

    Li, Pan; Song, Yuan; Wang, Shuai; Tao, Zheng; Yu, Shuili; Liu, Yanan

    2015-01-01

    The rate of reduction reactions of zero-valent metal nanoparticles is restricted by their agglomeration. Hydrodynamic cavitation was used to overcome the disadvantage in this study. Experiments for decolorization of methyl orange azo dye by zero-valent copper nanoparticles were carried out in aqueous solution with and without hydrodynamic cavitation. The results showed that hydrodynamic cavitation greatly accelerated the decolorization rate of methyl orange. The size of nanoparticles was decreased after hydrodynamic cavitation treatment. The effects of important operating parameters such as discharge pressure, initial solution pH, and copper nanoparticle concentration on the degradation rates were studied. It was observed that there was an optimum discharge pressure to get best decolorization performance. Lower solution pH were favorable for the decolorization. The pseudo-first-order kinetic constant for the degradation of methyl orange increased linearly with the copper dose. UV-vis spectroscopic and Fourier transform infrared (FT-IR) analyses confirmed that many degradation intermediates were formed. The results indicated hydroxyl radicals played a key role in the decolorization process. Therefore, the enhancement of decolorization by hydrodynamic cavitation could due to the deagglomeration of nanoparticles as well as the oxidation by the in situ generated hydroxyl radicals. These findings greatly increase the potential of the Cu(0)/hydrodynamic cavitation technique for use in the field of treatment of wastewater containing hazardous materials.

  12. Degradation of diclofenac sodium using combined processes based on hydrodynamic cavitation and heterogeneous photocatalysis.

    Science.gov (United States)

    Bagal, Manisha V; Gogate, Parag R

    2014-05-01

    Diclofenac sodium, a widely detected pharmaceutical drug in wastewater samples, has been selected as a model pollutant for degradation using novel combined approach of hydrodynamic cavitation and heterogeneous photocatalysis. A slit venturi has been used as cavitating device in the hydrodynamic cavitation reactor. The effect of various operating parameters such as inlet fluid pressure (2-4 bar) and initial pH of the solution (4-7.5) on the extent of degradation have been studied. The maximum extent of degradation of diclofenac sodium was obtained at inlet fluid pressure of 3 bar and initial pH as 4 using hydrodynamic cavitation alone. The loadings of TiO2 and H2O2 have been optimised to maximise the extent of degradation of diclofenac sodium. Kinetic study revealed that the degradation of diclofenac sodium fitted first order kinetics over the selected range of operating protocols. It has been observed that combination of hydrodynamic cavitation with UV, UV/TiO2 and UV/TiO2/H2O2 results in enhanced extents of degradation as compared to the individual schemes. The maximum extent of degradation as 95% with 76% reduction in TOC has been observed using hydrodynamic cavitation in conjunction with UV/TiO2/H2O2 under the optimised operating conditions. The diclofenac sodium degradation byproducts have been identified using LC/MS analysis.

  13. Disruption of Brewers' yeast by hydrodynamic cavitation: Process variables and their influence on selective release.

    Science.gov (United States)

    Balasundaram, B; Harrison, S T L

    2006-06-01

    Intracellular products, not secreted from the microbial cell, are released by breaking the cell envelope consisting of cytoplasmic membrane and an outer cell wall. Hydrodynamic cavitation has been reported to cause microbial cell disruption. By manipulating the operating variables involved, a wide range of intensity of cavitation can be achieved resulting in a varying extent of disruption. The effect of the process variables including cavitation number, initial cell concentration of the suspension and the number of passes across the cavitation zone on the release of enzymes from various locations of the Brewers' yeast was studied. The release profile of the enzymes studied include alpha-glucosidase (periplasmic), invertase (cell wall bound), alcohol dehydrogenase (ADH; cytoplasmic) and glucose-6-phosphate dehydrogenase (G6PDH; cytoplasmic). An optimum cavitation number Cv of 0.13 for maximum disruption was observed across the range Cv 0.09-0.99. The optimum cell concentration was found to be 0.5% (w/v, wet wt) when varying over the range 0.1%-5%. The sustained effect of cavitation on the yeast cell wall when re-circulating the suspension across the cavitation zone was found to release the cell wall bound enzyme invertase (86%) to a greater extent than the enzymes from other locations of the cell (e.g. periplasmic alpha-glucosidase at 17%). Localised damage to the cell wall could be observed using transmission electron microscopy (TEM) of cells subjected to less intense cavitation conditions. Absence of the release of cytoplasmic enzymes to a significant extent, absence of micronisation as observed by TEM and presence of a lower number of proteins bands in the culture supernatant on SDS-PAGE analysis following hydrodynamic cavitation compared to disruption by high-pressure homogenisation confirmed the selective release offered by hydrodynamic cavitation.

  14. Disinfection of bore well water with chlorine dioxide/sodium hypochlorite and hydrodynamic cavitation.

    Science.gov (United States)

    Wang, Yifei; Jia, Aiyin; Wu, Yue; Wu, Chunde; Chen, Lijun

    2015-01-01

    The effect of hydrodynamic cavitation (HC) on potable water disinfection of chemicals was investigated. The bore well water was introduced into HC set-up to examine the effect of HC alone and combination of HC and chemicals such as chlorine dioxide and sodium hypochlorite. The effect of inlet pressure and geometrical parameters on disinfection was studied using HC alone and the results showed that increasing inlet pressure and using more and bigger holes of orifice plates can result in a higher disinfection rates. When HC was combined with chemicals, HC can reduce the doses of the chemicals and shorten the time of disinfection. It was also found that the decrease in bacteria concentration followed a first-order kinetic model. As for the experiment of combination of HC and sodium hypochlorite for disinfection, HC not only improves the disinfection rate but also degrades natural organic matter and chloroform. Compared with only sodium hypochlorite disinfection, combined processes get higher disinfection rate and lower production of chloroform, particularly the pretreatment with HC enhances the disinfection rate by 32% and there is a simultaneous reduction in production of chloroform by 39%.

  15. Influences of hydrodynamic conditions, nozzle geometry on appearance of high submerged cavitating jets

    Directory of Open Access Journals (Sweden)

    Hutli Ezddin

    2013-01-01

    Full Text Available Based on visualization results of highly-submerged cavitating water jet obtained with digital camera, the influences of related parameters such as: injection pressure, nozzle diameter and geometry, nozzle mounting (for convergent / divergent flow, cavitation number and exit jet velocity, were investigated. In addition, the influence of visualization system position was also studied. All the parameters have been found to be of strong influence on the jet appearance and performance. Both hydro-dynamical and geometrical parameters are playing the main role in behavior and intensity of cavitation phenomenon produced by cavitating jet generator. Based on our considerable previous experience in working with cavitating jet generator, the working conditions were chosen in order to obtain measurable phenomenon. [Projekat Ministarstva nauke Republike Srbije, br. TR35046

  16. Hydrodynamic Nuclei Concentration Technique in Cavitation Research and Comparison to Phase-Doppler Measurements

    Science.gov (United States)

    Ebert, Eric; Kröger, Willfried; Damaschke, Nils

    2015-12-01

    Small particles, especially bubbles in the micro-meter range, influence the cavitation of the propellers. The prediction of cavitation inception and water quality measurements are important in cavitation research. The Hydrodynamic Nuclei Concentration (HDNC) technique can be used for reliable bubble concentration measurements in fluid flows. The HDNC technique bases on the analysis of scattered light from the cavitation nuclei in the water. The HDNC technique can distinguish between bubbles and solid particles. The particle type classification is important, because the number concentration of solid particles is often much higher than the nuclei concentration in cavitation tunnels and in seawater. Verification experiments show, that the HDNC technique reaches similar capabilities in number concentration estimation as Phase Doppler (PD) technique in much shorter acquisition time.

  17. Multi-focal laser surgery: cutting enhancement by hydrodynamic interactions between cavitation bubbles

    CERN Document Server

    Toytman, Ilya; Simanovski, Dmitri; Palanker, Daniel

    2010-01-01

    Transparent biological tissues can be precisely dissected with ultrafast lasers using optical breakdown in the tight focal zone. Typically, tissues are cut by sequential application of pulses, each of which produces a single cavitation bubble. We investigate the hydrodynamic interactions between simultaneous cavitation bubbles originating from multiple laser foci. Simultaneous expansion and collapse of cavitation bubbles can enhance the cutting efficiency by increasing the resulting deformations in tissue, and the associated rupture zone. An analytical model of the flow induced by the bubbles is presented and experimentally verified. The threshold strain of the material rupture is measured in a model tissue. Using the computational model and the experimental value of the threshold strain one can compute the shape of the rupture zone in tissue resulting from application of multiple bubbles. With the threshold strain of 0.7 two simultaneous bubbles produce a continuous cut when applied at the distance 1.35 time...

  18. Optimization of biodiesel production in a hydrodynamic cavitation reactor using used frying oil.

    Science.gov (United States)

    Ghayal, Dyneshwar; Pandit, Aniruddha B; Rathod, Virendra K

    2013-01-01

    The present work demonstrates the application of a hydrodynamic cavitation reactor for the synthesis of biodiesel with used frying oil as a feedstock. The synthesis involved the transesterification of used frying oil (UFO) with methanol in the presence of potassium hydroxide as a catalyst. The effect of geometry and upstream pressure of a cavitating orifice plate on the rate of transesterification reaction has been studied. It is observed that the micro level turbulence created by hydrodynamic cavitation somewhat overcomes the mass transfer limitations for triphasic transesterification reaction. The significant effects of upstream pressure on the rate of formation of methyl esters have been seen. It has been observed that flow geometry of orifice plate plays a crucial role in process intensification. With an optimized plate geometry of 2mm hole diameter and 25 holes, more than 95% of triglycerides have been converted to methyl esters in 10 min of reaction time with cavitational yield of 1.28 × 10(-3) (Grams of methyl esters produced per Joule of energy supplied). The potential of UFO to produce good quality methyl esters has been demonstrated.

  19. Hydrodynamic cavitation as an efficient method for the formation of sub-100 nm O/W emulsions with high stability

    Institute of Scientific and Technical Information of China (English)

    Zhiliang Zhang; Guangquan Wang; Yong Nie; Jianbing Ji

    2016-01-01

    Hydrodynamic cavitation, a newly developed process intensification technique, has demonstrated immense po-tential for intensifying diverse physical and chemical processes. In this study, hydrodynamic cavitation was ex-plored as an efficient method for the formation of sub-100 nm oil-in-water (O/W) emulsions with high stability. O/W emulsion with an average droplet size of 27 nm was successful y prepared. The average droplet size of O/W emulsions decreased with the increase of the inlet pressure, number of cavitation passes and surfac-tant concentration. The formed emulsion exhibited admirable physical stability during 8 months. Moreover, the hydrodynamic cavitation method can be generalized to fabricate large varieties of O/W emulsions, which showed great potential for large-scale formation of O/W emulsions with lower energy consumption.

  20. Degradation of imidacloprid using combined advanced oxidation processes based on hydrodynamic cavitation.

    Science.gov (United States)

    Patil, Pankaj N; Bote, Sayli D; Gogate, Parag R

    2014-09-01

    The harmful effects of wastewaters containing pesticides or insecticides on human and aquatic life impart the need of effectively treating the wastewater streams containing these contaminants. In the present work, hydrodynamic cavitation reactors have been applied for the degradation of imidacloprid with process intensification studies based on different additives and combination with other similar processes. Effect of different operating parameters viz. concentration (20-60 ppm), pressure (1-8 bar), temperature (34 °C, 39 °C and 42 °C) and initial pH (2.5-8.3) has been investigated initially using orifice plate as cavitating device. It has been observed that 23.85% degradation of imidacloprid is obtained at optimized set of operating parameters. The efficacy of different process intensifying approaches based on the use of hydrogen peroxide (20-80 ppm), Fenton's reagent (H2O2:FeSO4 ratio as 1:1, 1:2, 2:1, 2:2, 4:1 and 4:2), advanced Fenton process (H2O2:Iron Powder ratio as 1:1, 2:1 and 4:1) and combination of Na2S2O8 and FeSO4 (FeSO4:Na2S2O8 ratio as 1:1, 1:2, 1:3 and 1:4) on the extent of degradation has been investigated. It was observed that near complete degradation of imidacloprid was achieved in all the cases at optimized values of process intensifying parameters. The time required for complete degradation of imidacloprid for approach based on hydrogen peroxide was 120 min where as for the Fenton and advance Fenton process, the required time was only 60 min. To check the effectiveness of hydrodynamic cavitation with different cavitating devices, few experiments were also performed with the help of slit venturi as a cavitating device at already optimized values of parameters. The present work has conclusively established that combined processes based on hydrodynamic cavitation can be effectively used for complete degradation of imidacloprid.

  1. Detecting Inception of Hydrodynamic Cavitation Noise of Ships using Quadratic Phase Coupling Index as an Indicator

    Directory of Open Access Journals (Sweden)

    M. Sandhya

    2015-03-01

    Full Text Available There is ever increasing interest in underwater noise control onboard ships as part of concerted efforts to reduce ship’s radiated noise. Reduction of radiated noise is considered important as it will affect the performance of hydro-acoustic systems such as sonars, echo sounders, towed systems, etc. Out of three major sources of noise onboard ships, viz., machinery, propeller, and hydrodynamic noise, propeller noise is considered a major source beyond certain speed at which propellers cavitate produces cavitation noise. The inception speed of propeller cavitation is generally accompanied by sudden increase in radiated noise level of 8-15 dB when measured using a hydrophone placed on the seabed. This paper attempts to establish the concept of quadratic phase coupling index as an indicator to detect inception of cavitation of ship propellers. This concept was tested on actual ship radiated noise data measured at sea for evaluating its effectiveness.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.53-62, DOI:http://dx.doi.org/10.14429/dsj.65.7885

  2. Cavitation

    CERN Document Server

    Young, F Ronald

    1999-01-01

    First published by McGraw-Hill in 1989, this book provides a unified treatment of cavitation, a phenomenon which extends across the boundaries of many fields. The approach is wide-ranging and the aim is to give due consideration to the many aspects of cavitation in proportion to their importance. Particular attention is paid to the diverse situations in which cavitation occurs and to its practical applications.

  3. Hydrodynamic cavitation applied to industrial wastewater; Tratamiento de efluentes industriales mediante cavitacion hidrodinamica

    Energy Technology Data Exchange (ETDEWEB)

    Benito, Y.; Arrojo, S.

    2006-07-01

    The use environmental technology of the phenomenon known as cavitation has opened in the last new years alternatives for the treatment especially for industrial effluents. CIEMAT has designed and constructed a plant of cavitation hydrodynamics to take to end experiments that it allows us to show the possibilities of this technology as process of advanced oxidation of low cost. The experimentation has been made with water contaminated by substances like toluene and some derivatives, chloride organic compounds, xylenes, ammonia, wastewater from the ended of leather sector, there being achieved important reductions of the DQO (of the order of 60%) in short times. This work shows the results obtained in the experimentation of waters contaminated with toluene and p-nitrophenol. (Author)

  4. Multifocal laser surgery: cutting enhancement by hydrodynamic interactions between cavitation bubbles.

    Science.gov (United States)

    Toytman, I; Silbergleit, A; Simanovski, D; Palanker, D

    2010-10-01

    Transparent biological tissues can be precisely dissected with ultrafast lasers using optical breakdown in the tight focal zone. Typically, tissues are cut by sequential application of pulses, each of which produces a single cavitation bubble. We investigate the hydrodynamic interactions between simultaneous cavitation bubbles originating from multiple laser foci. Simultaneous expansion and collapse of cavitation bubbles can enhance the cutting efficiency, by increasing the resulting deformations in tissue, and the associated rupture zone. An analytical model of the flow induced by the bubbles is presented and experimentally verified. The threshold strain of the material rupture is measured in a model tissue. Using the computational model and the experimental value of the threshold strain one can compute the shape of the rupture zone in tissue resulting from application of multiple bubbles. With the threshold strain of 0.7 two simultaneous bubbles produce a continuous cut when applied at the distance 1.35 times greater than that required in sequential approach. Simultaneous focusing of the laser in multiple spots along the line of intended cut can extend this ratio to 1.7. Counterpropagating jets forming during collapse of two bubbles in materials with low viscosity can further extend the cutting zone-up to approximately a factor of 1.5.

  5. Effect of hydrodynamic cavitation in the tissue erosion by pulsed high-intensity focused ultrasound (pHIFU)

    Science.gov (United States)

    Zhou, Yufeng; Gao, Xiaobin Wilson

    2016-09-01

    High-intensity focused ultrasound (HIFU) is emerging as an effective therapeutic modality in clinics. Besides the thermal ablation, tissue disintegration is also possible because of the interaction between the distorted HIFU bursts and either bubble cloud or boiling bubble. Hydrodynamic cavitation is another type of cavitation and has been employed widely in industry, but its role in mechanical erosion to tissue is not clearly known. In this study, the bubble dynamics immediately after the termination of HIFU exposure in the transparent gel phantom was captured by high-speed photography, from which the bubble displacement towards the transducer and the changes of bubble size was quantitatively determined. The characteristics of hydrodynamic cavitation due to the release of the acoustic radiation force and relaxation of compressed surrounding medium were found to associate with the number of pulses delivered and HIFU parameters (i.e. pulse duration and pulse repetition frequency). Because of the initial big bubble (~1 mm), large bubble expansion (up to 1.76 folds), and quick bubble motion (up to ~1 m s-1) hydrodynamic cavitation is significant after HIFU exposure and may lead to mechanical erosion. The shielding effect of residual tiny bubbles would reduce the acoustic energy delivered to the pre-existing bubble at the focus and, subsequently, the hydrodynamic cavitation effect. Tadpole shape of mechanical erosion in ex vivo porcine kidney samples was similar to the contour of bubble dynamics in the gel. Liquefied tissue was observed to emit towards the transducer through the punctured tissue after HIFU exposure in the sonography. In summary, the release of HIFU exposure-induced hydrodynamic cavitation produces significant bubble expansion and motion, which may be another important mechanism of tissue erosion. Understanding its mechanism and optimizing the outcome would broaden and enhance HIFU applications.

  6. Biodiesel production process intensification using a rotor-stator type generator of hydrodynamic cavitation.

    Science.gov (United States)

    Crudo, Daniele; Bosco, Valentina; Cavaglià, Giuliano; Grillo, Giorgio; Mantegna, Stefano; Cravotto, Giancarlo

    2016-11-01

    Triglyceride transesterification for biodiesel production is a model reaction which is used to compare the conversion efficiency, yield, reaction time, energy consumption, scalability and cost estimation of different reactor technology and energy source. This work describes an efficient, fast and cost-effective procedure for biodiesel preparation using a rotating generator of hydrodynamic cavitation (HC). The base-catalyzed transesterification (methanol/sodium hydroxide) has been carried out using refined and bleached palm oil and waste vegetable cooking oil. The novel HC unit is a continuous rotor-stator type reactor in which reagents are directly fed into the controlled cavitation chamber. The high-speed rotation of the reactor creates micron-sized droplets of the immiscible reacting mixture leading to outstanding mass and heat transfer and enhancing the kinetics of the transesterification reaction which completes much more quickly than traditional methods. All the biodiesel samples obtained respect the ASTM standard and present fatty acid methyl ester contents of >99% m/m in both feedstocks. The electrical energy consumption of the HC reactor is 0.030kWh per L of produced crude biodiesel, making this innovative technology really quite competitive. The reactor can be easily scaled-up, from producing a few hundred to thousands of liters of biodiesel per hour while avoiding the risk of orifices clogging with oil impurities, which may occur in conventional HC reactors. Furthermore it requires minimal installation space due to its compact design, which enhances overall security.

  7. Degradation of 4-chloro 2-aminophenol using a novel combined process based on hydrodynamic cavitation, UV photolysis and ozone.

    Science.gov (United States)

    Barik, Arati J; Gogate, Parag R

    2016-05-01

    The degradation of 4-chloro 2-aminophenol (4C2AP), an acute toxic organic compound, has been studied using different approaches based on the hydrodynamic cavitation (HC) with orifice plate as cavitating device, photolysis (UV) and ozonation (O3). The dependency of extent of degradation on operating parameters like operating pressure (2-5 bar), initial pH (3-8) and temperature (30-38 °C) have been established initially to maximize the efficacy of hydrodynamic cavitation. Subsequently the degradation has been studied using combined treatment strategies as HC+UV, HC+O3, UV+O3 and HC+UV+O3 at the established optimum parameters of operating temperature as 30 °C, initial pH of 6 and inlet pressure of 4 bar. The maximum extent of degradation as 96.85% and 73.6% reduction in TOC has been obtained using hydrodynamic cavitation in combination with UV photolysis and ozonation under the optimized operating conditions. The degradation products of 4C2AP have been identified using GC-MS. The present work has clearly established the efficacy of combined treatment approach (HC+UV+O3) for the removal of organic pollutant for the first time.

  8. Sonochemical and hydrodynamic cavitation reactors for laccase/hydrogen peroxide cotton bleaching.

    Science.gov (United States)

    Gonçalves, Idalina; Martins, Madalena; Loureiro, Ana; Gomes, Andreia; Cavaco-Paulo, Artur; Silva, Carla

    2014-03-01

    The main goal of this work is to develop a novel and environmental-friendly technology for cotton bleaching with reduced processing costs. This work exploits a combined laccase-hydrogen peroxide process assisted by ultrasound. For this purpose, specific reactors were studied, namely ultrasonic power generator type K8 (850 kHz) and ultrasonic bath equipment Ultrasonic cleaner USC600TH (45 kHz). The optimal operating conditions for bleaching were chosen considering the highest levels of hydroxyl radical production and the lowest energy input. The capacity to produce hydroxyl radicals by hydrodynamic cavitation was also assessed in two homogenizers, EmulsiFlex®-C3 and APV-2000. Laccase nanoemulsions were produced by high pressure homogenization using BSA (bovine serum albumin) as emulsifier. The bleaching efficiency of these formulations was tested and the results showed higher whiteness values when compared to free laccase. The combination of laccase-hydrogen peroxide process with ultrasound energy produced higher whiteness levels than those obtained by conventional methods. The amount of hydrogen peroxide was reduced 50% as well as the energy consumption in terms of temperature (reduction of 40 °C) and operating time (reduction of 90 min).

  9. Degradation of 2,4-dinitrophenol using a combination of hydrodynamic cavitation, chemical and advanced oxidation processes.

    Science.gov (United States)

    Bagal, Manisha V; Gogate, Parag R

    2013-09-01

    In the present work, degradation of 2,4-dinitrophenol (DNP), a persistent organic contaminant with high toxicity and very low biodegradability has been investigated using combination of hydrodynamic cavitation (HC) and chemical/advanced oxidation. The cavitating conditions have been generated using orifice plate as a cavitating device. Initially, the optimization of basic operating parameters have been done by performing experiments over varying inlet pressure (over the range of 3-6 bar), temperature (30 °C, 35 °C and 40 °C) and solution pH (over the range of 3-11). Subsequently, combined treatment strategies have been investigated for process intensification of the degradation process. The effect of HC combined with chemical oxidation processes such as hydrogen peroxide (HC/H2O2), ferrous activated persulfate (HC/Na2S2O8/FeSO4) and HC coupled with advanced oxidation processes such as conventional Fenton (HC/FeSO4/H2O2), advanced Fenton (HC/Fe/H2O2) and Fenton-like process (HC/CuO/H2O2) on the extent of degradation of DNP have also been investigated at optimized conditions of pH 4, temperature of 35 °C and inlet pressure of 4 bar. Kinetic study revealed that degradation of DNP fitted first order kinetics for all the approaches under investigation. Complete degradation with maximum rate of DNP degradation has been observed for the combined HC/Fenton process. The energy consumption analysis for hydrodynamic cavitation based process has been done on the basis of cavitational yield. Degradation intermediates have also been identified and quantified in the current work. The synergistic index calculated for all the combined processes indicates HC/Fenton process is more feasible than the combination of HC with other Fenton like processes.

  10. 局部空泡水翼性能研究%Research on the Hydrodynamic Performance of Partially Cavitating Hydrofoils

    Institute of Scientific and Technical Information of China (English)

    谭睿博; 许劲松

    2013-01-01

    空泡对水翼的水动力特性具有重要的影响,使用数值模拟方法研究空泡特性及其机理有着广泛的工程应用价值.对二维NACA翼型的模拟结果表明,基于势流理论的边界元积分方法适用于局部空泡水翼的性能研究,翼型几何参数变化对空泡长度和升力性能均有显著影响,在水翼设计与使用过程中必须对空泡发生与变化给予充分关注.%Cavitation has extremely important influence on hydrodynamic performance of the hydrofoils.Numerical simulation is valuable for study on the characteristics and mechanism of cavitating flow.Application of a non-linear boundary element method on the partially cavitating hydrofoil shows that the lift performance of hydrofoils changes considerably with the occurrence and development of the partial cavitation.It must be completely concerned during hydrofoil design and operation.

  11. The efficiency of a new hydrodynamic cavitation pilot system on Artemia salina cysts and natural population of copepods and bacteria under controlled mesocosm conditions.

    Science.gov (United States)

    Cvetković, Martina; Grego, Mateja; Turk, Valentina

    2016-04-15

    A study of the efficiency of hydrodynamic cavitation and separation was carried out to evaluate an innovative, environmentally safe and acceptable system for ballast water treatment for reducing the risk of introducing non-native species worldwide. Mesocosm experiments were performed to assess the morphological changes and viability of zooplankton (copepods), Artemia salina cysts, and the growth potential of marine bacteria after the hydrodynamic cavitation treatment with a different number of cycles. Our preliminary results confirmed the significant efficiency of the treatment since more than 98% of the copepods and A. salina cysts were damaged, in comparison with the initial population. The efficiency increased with the number of the hydrodynamic cavitation cycles, or in combination with a separation technique for cysts. There was also a significant decrease in bacterial abundance and growth rate, compared to the initial number and growth potential.

  12. Application of Technology of Hydrodynamic Cavitation Processing High-Viscosity Oils for the Purpose of Improving the Rheological Characteristics of Oils

    Science.gov (United States)

    Zemenkov, Y. D.; Zemenkova, M. Y.; Vengerov, A. A.; Brand, A. E.

    2016-10-01

    There is investigated the technology of hydrodynamic cavitational processing viscous and high-viscosity oils and the possibility of its application in the pipeline transport system for the purpose of increasing of rheological properties of the transported oils, including dynamic viscosity shear stress in the article. It is considered the possibility of application of the combined hydrodynamic cavitational processing with addition of depressor additive for identification of effect of a synergism. It is developed the laboratory bench and they are presented results of modeling and laboratory researches. It is developed the hardware and technological scheme of application of the developed equipment at industrial objects of pipeline transport.

  13. Synergetic effect of combination of AOP's (hydrodynamic cavitation and H{sub 2}O{sub 2}) on the degradation of neonicotinoid class of insecticide

    Energy Technology Data Exchange (ETDEWEB)

    Raut-Jadhav, Sunita [Vishwakarma Institute of Technology, Pune 411037 (India); Saharan, Virendra Kumar [Chemical Engineering Department, M. N. I. T, Jaipur, Rajasthan, 302001 (India); Pinjari, Dipak [Chemical Engineering Department, Institute of Chemical Technology, (ICT), Matunga, Mumbai, 400019 (India); Sonawane, Shirish, E-mail: shirishsonawane09@gmail.com [Chemical Engineering Department, N. I. T Warangal, Andhra Pradesh 506004 (India); Saini, Daulat, E-mail: dsaini2010@gmail.com [National Chemical Laboratory, Pune, 411008 (India); Pandit, Aniruddha, E-mail: dr.pandit@gmail.com [Chemical Engineering Department, Institute of Chemical Technology, (ICT), Matunga, Mumbai, 400019 (India)

    2013-10-15

    Highlights: • Degradation of imidacloprid using hydrodynamic cavitation based techniques. • Combination of hydrodynamic cavitation and H{sub 2}O{sub 2} shows substantial synergetic effect. • Synergetic coefficient of combined process is 22.79. • Degradation mechanism of imidacloprid has been proposed. -- Abstract: In the present work, degradation of imidacloprid (neonicotinoid class of insecticide) in aqueous solution has been systematically investigated using hydrodynamic cavitation and combination of hydrodynamic cavitation (HC) and H{sub 2}O{sub 2}. Initially, effect of different operating parameters such as inlet pressure to the cavitating device (5–20 bar) and operating pH (2–7.5) has been investigated. Optimization of process parameters was followed by the study of effect of combination of HC and H{sub 2}O{sub 2} process on the rate of degradation of imidacloprid. Significant enhancement in the rate of degradation of imidacloprid has been observed using HC + H{sub 2}O{sub 2} process which lead to a complete degradation of imidacloprid in 45 min of operation using optimal molar ratio of imidacloprid:H{sub 2}O{sub 2} as 1:40. Substantial synergetic effect has been observed using HC + H{sub 2}O{sub 2} process which confer the synergetic coefficient of 22.79. An attempt has been made to investigate and compare the energy efficiency and extent of mineralization of individual and combined processes applied in the present work. Identification of the byproducts formed during degradation of imidacloprid has also been done using LC–MS analysis. The present work has established a fact that hydrodynamic cavitation in combination with H{sub 2}O{sub 2} can be effectively used for degradation of imidacloprid.

  14. Dynamical behaviors of hydrodynamic cavitation bubble under ultrasound field%声场中水力空化泡的动力学特性

    Institute of Scientific and Technical Information of China (English)

    沈壮志; 林书玉

    2011-01-01

    以水为工作介质,考虑了液体黏性、表面张力、可压缩性及湍流作用等情况,对文丘里管反应器中空化泡在声场作用下的动力学行为特性进行了数值研究.分析了超声波频率、声压及喉径比对空化泡运动特性以及空化泡崩溃时所形成泡温以及压力脉冲的影响.结果表明,超声将水力空化泡运动调制成稳态空化,有利于增强空化效果.%Considering liquid viscosity,surface tension,liquid compressibility and turbulence,the dynamical behaviors of cavitation bubble in venturi cavitation reactor are numerically investigated with using acoustic field regarding water as a work medium.The effects of acoustic frequency,acoustic pressure and ratio of throat to pipe diameter on cavitation bubble dynamics,bubble temperature and pressure pulse by rapid collapse of cavitation bubble are analysed.The results show that bubble motion of hydrodynamic cavitation modulated by ultrasound,becomes the high energy stable cavitation.It is favorable for enhancing the cavitation effect.

  15. Simultaneous treatment (cell disruption and lipid extraction) of wet microalgae using hydrodynamic cavitation for enhancing the lipid yield.

    Science.gov (United States)

    Lee, Ilgyu; Han, Jong-In

    2015-06-01

    Simultaneous treatment (combining with cell disruption and lipid extraction) using hydrodynamic cavitation (HC) was applied to Nannochloropsis salina to demonstrate a simple and integrated way to produce oil from wet microalgae. A high lipid yield from the HC (25.9-99.0%) was observed compared with autoclave (16.2-66.5%) and ultrasonication (5.4-26.9%) in terms of the specific energy input (500-10,000 kJ/kg). The optimal conditions for the simultaneous treatment were established using a statistical approach. The efficiency of the simultaneous method was also demonstrated by comparing each separate treatment. The maximum lipid yield (predicted: 45.9% and experimental: 45.5%) was obtained using 0.89% sulfuric acid with a cavitation number of 1.17 for a reaction time of 25.05 min via response surface methodology. Considering its comparable extractability, energy-efficiency, and potential for scale-up, HC may be a promising method to achieve industrial-scale microalgae operation.

  16. Optimisation on pretreatment of rubber seed (Hevea brasiliensis) oil via esterification reaction in a hydrodynamic cavitation reactor.

    Science.gov (United States)

    Bokhari, Awais; Chuah, Lai Fatt; Yusup, Suzana; Klemeš, Jiří Jaromír; Kamil, Ruzaimah Nik M

    2016-01-01

    Pretreatment of the high free fatty acid rubber seed oil (RSO) via esterification reaction has been investigated by using a pilot scale hydrodynamic cavitation (HC) reactor. Four newly designed orifice plate geometries are studied. Cavities are induced by assisted double diaphragm pump in the range of 1-3.5 bar inlet pressure. An optimised plate with 21 holes of 1mm diameter and inlet pressure of 3 bar resulted in RSO acid value reduction from 72.36 to 2.64 mg KOH/g within 30 min of reaction time. Reaction parameters have been optimised by using response surface methodology and found as methanol to oil ratio of 6:1, catalyst concentration of 8 wt%, reaction time of 30 min and reaction temperature of 55°C. The reaction time and esterified efficiency of HC was three fold shorter and four fold higher than mechanical stirring. This makes the HC process more environmental friendly.

  17. Intensified depolymerization of aqueous polyacrylamide solution using combined processes based on hydrodynamic cavitation, ozone, ultraviolet light and hydrogen peroxide.

    Science.gov (United States)

    Prajapat, Amrutlal L; Gogate, Parag R

    2016-07-01

    The present work deals with intensification of depolymerization of polyacrylamide (PAM) solution using hydrodynamic cavitation (HC) reactors based on a combination with hydrogen peroxide (H2O2), ozone (O3) and ultraviolet (UV) irradiation. Effect of inlet pressure in hydrodynamic cavitation reactor and power dissipation in the case of UV irradiation on the extent of viscosity reduction has been investigated. The combined approaches such as HC+UV, HC+O3, HC+H2O2, UV+H2O2 and UV+O3 have been subsequently investigated and found to be more efficient as compared to individual approaches. For the approach based on HC+UV+H2O2, the extent of viscosity reduction under the optimized conditions of HC (3 bar inlet pressure)+UV (8 W power)+H2O2 (0.2% loading) was 97.27% in 180 min whereas individual operations of HC (3 bar inlet pressure) and UV (8 W power) resulted in about 35.38% and 40.83% intrinsic viscosity reduction in 180 min respectively. In the case of HC (3 bar inlet pressure)+UV (8 W power)+ozone (400 mg/h flow rate) approach, the extent of viscosity reduction was 89.06% whereas individual processes of only ozone (400 mg/h flow rate), ozone (400 mg/h flow rate)+HC (3 bar inlet pressure) and ozone (400 mg/h flow rate)+UV (8 W power) resulted in lower extent of viscosity reduction as 50.34%, 60.65% and 75.31% respectively. The chemical structure of the treated PAM by all approaches was also characterized using FTIR (Fourier transform infrared) spectra and it was established that no significant chemical structure changes were obtained during the treatment. Overall, it can be said that the combination of HC+UV+H2O2 is an efficient approach for the depolymerization of PAM solution.

  18. Optimization of a heterogeneous catalytic hydrodynamic cavitation reactor performance in decolorization of Rhodamine B: application of scrap iron sheets.

    Science.gov (United States)

    Basiri Parsa, Jalal; Ebrahimzadeh Zonouzian, Seyyed Alireza

    2013-11-01

    A low pressure pilot scale hydrodynamic cavitation (HC) reactor with 30 L volume, using fixed scrap iron sheets, as the heterogeneous catalyst, with no external source of H2O2 was devised to investigate the effects of operating parameters of the HC reactor performance. In situ generation of Fenton reagents suggested an induced advanced Fenton process (IAFP) to explain the enhancing effect of the used catalyst in the HC process. The reactor optimization was done based upon the extent of decolorization (ED) of aqueous solution of Rhodamine B (RhB). To have a perfect study on the pertinent parameters of the heterogeneous catalyzed HC reactor, the following cases as, the effects of scrap iron sheets, inlet pressure (2.4-5.8 bar), the distance between orifice plates and catalyst sheets (submerged and inline located orifice plates), back-pressure (2-6 bar), orifice plates type (4 various orifice plates), pH (2-10) and initial RhB concentration (2-14 mg L(-1)) have been investigated. The results showed that the highest cavitational yield can be obtained at pH 3 and initial dye concentration of 10 mg L(-1). Also, an increase in the inlet pressure would lead to an increase in the ED. In addition, it was found that using the deeper holes (thicker orifice plates) would lead to lower ED, and holes with larger diameter would lead to the higher ED in the same cross-sectional area, but in the same holes' diameters, higher cross-sectional area leads to the lower ED. The submerged operation mode showed a greater cavitational effects rather than the inline mode. Also, for the inline mode, the optimum value of 3 bar was obtained for the back-pressure condition in the system. Moreover, according to the analysis of changes in the UV-Vis spectra of RhB, both degradation of RhB chromophore structure and N-deethylation were occurred during the catalyzed HC process.

  19. Optimization of hydrodynamic cavitations reactor efficiency for biodiesel production by response surface methods (Case study: Sunflower oil

    Directory of Open Access Journals (Sweden)

    H Javadikia

    2017-05-01

    Full Text Available Introduction Biofuels are considered as one of the largest sources of renewable fuels or replacement of fossil fuels. Combustion of plant-based fuels is the indirect use of solar energy. Biofuels significantly have less pollution than other fossil fuels and can easily generate from residual plant material. Waste and residues of foods and wastewater can also be a good source for biofuel production. Transesterification method (one of biodiesel production methods is the most common forms to produce mono-alkyl esters from vegetable oil and animal fats. The procedure aims are reduction the oil viscosity during the reaction between triglycerides and alcohol in the presence of a catalyst or without it. In this study, the method of transesterification with alkaline catalysts is used that it is the most common and most commercial biodiesel production method. In this study, configurations of made hydrodynamic cavitation reactor were studied to measure biodiesel fuel quality and enhanced device performance with optimum condition. The Design Expert software and response surface methodology were used to get this purpose. Materials and Methods Transesterification method was used in this study. The procedure aims were reduction of the oil viscosity during the reaction between triglycerides and alcohol in the presence of a catalyst or without it. Materials needed in the production of biodiesel transesterification method include: vegetable oil, alcohol and catalysts. The used oil in the production of biodiesel was sunflower oil, which was used 0.6 liters per each test in the production process base on titration method. Methanol with purity of 99.8 percent and the molar ratio of 6:1 to oil was used based on titration equation and according to the results of other researchers. The used catalyst in continuous production process was high-purity sodium hydroxide (99% that it is one of alkaline catalysts. Weight of hydroxide was 1% of the used oil weight in the

  20. Farmer Training Fund Set Up

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>On the afternoon of February 12, 2007, the China Friendship Foundation for Peace and Development (CFFPD) held the inauguration of the Farmer Training Fund and a press conference. Li Xiaolin, CPAFFC vice president and chairman of the Board of Directors of the CFFPD, who announced the inauguration, said, the Farmer Training Fund is set up by the CFFPD timely in response to the Party’s call of "building a new socialist countryside" and a

  1. 孔板水力空化装置的数值模拟%Simulation of Hydrodynamic Cavitation Equipment with Orifice Plates

    Institute of Scientific and Technical Information of China (English)

    章昱; 李育敏; 计建炳

    2011-01-01

    基于FLUENT软件,采用]k-ω模型对孔板水力空化进行数值模拟,将相同条件下模拟所得的空化区与实验空化区进行比较.结果表明,模拟计算得到的汽含率分布与实验拍摄的汽含率分布相似,k-ω模型模拟结果与实验结果吻合.采用该模型分析了不同入口压力、孔板结构参数、液体物性参数对空化强度的影响,模拟结果表明,入口压力越大,空化强度越剧烈;增加孔径和孔的数量使空化强度减弱;增大液体密度和粘度使空化强度减弱;增大液体初始含气量使空化强度先增大后减小.%Based on the software FLUENT, the hydrodynamic cavitation with orifice plates was simulated using the k-ω model. The simulation results were compared with experimental data at the same situations, which showed that the distribution of vapor fraction by simulation was similar to that of experiment. The influences of inlet pressure, structures of orifice plate and physical characters of liquid on cavitation intensity were investigated by simulation using this model. The intensity of cavitation increased with increasing of inlet pressure and the orifice diameter and number. The intensity of cavitation decreased as the increase of density and viscosity of liquid, when the initial gas holdup increased, the intensity of cavitation increased first and then weaken.

  2. Cavitation simulation on marine propellers

    DEFF Research Database (Denmark)

    Shin, Keun Woo

    is reproduced in the simulation. The overall results suggest the possibility of the cavitation model in the RANS solver to be used for practical applications in propeller design process as a complementary tool to the cavitation tunnel test and the other numerical methods. The outstanding issue for cloudy...... developed in the last decade. They show the potential for the simulation of propeller cavitation with robustness, but they are still to be more proved for practical applications. In the present work, hydrodynamic and numerical characteristics of several cavitation models developed for a viscous flow solver...... are investigated, and one of the cavitation models is verified for the cavitation simulation on marine propellers. Three cavitation models with a vapor transport equation and a cavitation model with a barotropic state law are implemented in the in-house RANS solver, EllipSys. The numerical results for cavitating...

  3. Hydrodynamic cavitation in combination with the ozone, hydrogen peroxide and the UV-based advanced oxidation processes for the removal of natural organic matter from drinking water.

    Science.gov (United States)

    Čehovin, Matej; Medic, Alojz; Scheideler, Jens; Mielcke, Jörg; Ried, Achim; Kompare, Boris; Žgajnar Gotvajn, Andreja

    2017-07-01

    Natural organic matter in drinking water is causing concern especially due to the formation of disinfection by-products (DBPs) by chlorine, as these are proven to have adverse health effects on consumers. In this research, humic acid was used as a source of dissolved organic carbon (DOC) in drinking water (up to 3mgL(-1)). The efficiency of DOC removal was studied by applying O3, H2O2/O3, H2O2/UV and O3/UV advanced oxidation processes (AOPs) alone and combined with hybrid hydrodynamic cavitation (HC), generated by an orifice plate, as this technology recently shows promising potential for the treatment of water, containing recalcitrant organic substances. It was observed that the combined treatment by HC could significantly affect the performance of the applied AOPs, with as little as 3-9 passes through the cavitation generators. For O3 and H2O2 dosages up to 2 and 4mgL(-1), respectively, and UV dosage up to 300mJcm(-2), HC enhanced DOC removal by 5-15% in all combinations, except for O3/UV AOPs. Overall, the potential benefits of HC for DOC removal were emphasized for low ratio between applied oxidants to DOC and high UV absorbance of the sample. Investigated DBPs formation potentials require special attention for H2O2/UV AOPs and combinations with HC. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Cavitation simulation on marine propellers

    DEFF Research Database (Denmark)

    Shin, Keun Woo

    flows on a 2D hydrofoil are compared with the experimental results. In the current implementation, three models with a vapor transport equation show numerical stability and equivalently good accuracy in simulating steady and unsteady sheet cavitation. More validations for cavitating flows on 3D...... hydrofoils and conventional/highly-skewed propellers are performed with one of three cavitation models proven in 2D analysis. 3D cases also show accuracy and robustness of numerical method in simulating steady and unsteady sheet cavitation on complicated geometries. Hydrodynamic characteristics of cavitation...

  5. Can Cavitation Be Anticipated?

    Energy Technology Data Exchange (ETDEWEB)

    Allgood, G.O.; Dress, W.B.; Hylton, J.O.; Kercel, S.W.

    1999-04-25

    The major problem with cavitation in pumps and hydraulic systems is that there is no effective (conventional) method for detecting or predicting its inception. The traditional method of recognizing cavitation in a pump is to declare the event occurring when the total head drops by some arbitrary value (typically 3%) in response to a pressure reduction at the pump inlet. However, the device is already seriously cavitating when this happens. What is actually needed is a practical method to detect impending rather than incipient cavitation. Whereas the detection of incipient cavitation requires the detection of features just after cavitation starts, the anticipation of cavitation requires the detection and identification of precursor features just before it begins. Two recent advances that make this detection possible. The first is acoustic sensors with a bandwidth of 1 MHz and a dynamic range of 80 dB that preserve the fine details of the features when subjected to coarse vibrations. The second is the application of Bayesian parameter estimation which makes it possible to separate weak signals, such as those present in cavitation precursors, from strong signals, such as pump vibration. Bayesian parameter estimation derives a model based on cavitation hydrodynamics and produces a figure of merit of how well it fits the acquired data. Applying this model to an anticipatory engine should lead to a reliable method of anticipating cavitation before it occurs. This paper reports the findings of precursor features using high-performance sensors and Bayesian analysis of weak acoustic emissions in the 100-1000kHz band from an experimental flow loop.

  6. Cavitation instabilities and rotordynamic effects in turbopumps and hydroturbines turbopump and inducer cavitation, experiments and design

    CERN Document Server

    Salvetti, Maria

    2017-01-01

    The book provides a detailed approach to the physics, fluid dynamics, modeling, experimentation and numerical simulation of cavitation phenomena, with special emphasis on cavitation-induced instabilities and their implications on the design and operation of high performance turbopumps and hydraulic turbines. The first part covers the fundamentals (nucleation, dynamics, thermodynamic effects, erosion) and forms of cavitation (attached cavitation, cloud cavitation, supercavitation, vortex cavitation) relevant to hydraulic turbomachinery, illustrates modern experimental techniques for the characterization, visualization and analysis of cavitating flows, and introduces the main aspects of the hydrodynamic design and performance of axial inducers, centrifugal turbopumps and hydo-turbines. The second part focuses on the theoretical modeling, experimental analysis, and practical control of cavitation-induced fluid-dynamic and rotordynamic instabilities of hydraulic turbomachinery, with special emphasis on cavitating...

  7. Setting up a medical portrait studio.

    Science.gov (United States)

    Neff, Laura L; Humphrey, Clinton D; Kriet, J David

    2010-05-01

    Consistency of photographic documentation is essential for facial plastic surgery, a visual surgical subspecialty. Photographs are often used to validate surgical outcomes but have many other uses including education, publication, and marketing. Utilization of a properly equipped medical portrait studio will dramatically increase the quality of photographic images. In this article, the authors discuss the steps necessary to set up and use an officebased portrait studio. Copyright 2010 Elsevier Inc. All rights reserved.

  8. Improved mortar set-up technique

    CSIR Research Space (South Africa)

    De Villiers, D

    2010-05-01

    Full Text Available www.csir.co.za Close Rage Reference Device (Prismatic Mirror) • Problems with aiming posts • Description of the Prismatic Mirror • Prismatic Mirror set-up • Passing adjustment bearings and paralleling • Mortar lay • First shot and small.... Prismatic Mirror (Close Rage Reference Device) Slide 16 © CSIR 2008 www.csir.co.za Prismatic Mirror (Close Rage Reference Device) Slide 17 © CSIR 2008 www.csir.co.za C2A1 Bearing Scale (Close Rage Reference...

  9. Trappers set up trap for lizard

    Science.gov (United States)

    2000-01-01

    In hope of catching a large monitor lizard seen in the area, state-licensed animal trappers Dewey Kessler and James Dean (at left), with Gary Povitch (kneeling) of the U.S. Wildlife and Dan Turner (standing) set up a trap on KSC. The lizard has been spotted recently near S.R. 3, a route into the Center, by several area residents. Turner is a monitor expert. The lizard is not a native of the area, and possibly a released pet. Dean is working with the cooperation of KSC and the Merritt Island National Wildlife Refuge.

  10. Setting up a structured laboratory mentoring programme

    Directory of Open Access Journals (Sweden)

    Talkmore Maruta

    2013-03-01

    Full Text Available Introduction: Laboratory mentoring programmes can be an important vehicle to establish and solidify quality management systems and help laboratories achieve accreditation goals. Different mentoring approaches have been used with varying levels of success. The authors provide a guide to implementing a structured laboratory mentorship programme based on their practical field experience.Method: The study is based on experience in Lesotho as well as subsequent roll out of a similar approach in the other African countries of Zimbabwe, Mozambique, Swaziland and Cameroon between 2009 and 2011.Summary: We highlight critical elements to consider when setting up a long-term, sustainable and well-structured mentorship programme. These elements include: well-defined goals; sufficient length of mentor engagement on site; standardised approach across laboratories; measurement of progress using standardised tools; well-structured reporting mechanisms; alignment of the programme with overall Ministry of Health plans; and selection and training of the mentors. These elements will differ in application, depending on countries’ needs and available resources. A structured approach allows for scalability, comparison across laboratories and countries and an easier approach to budgeting and planning for countries intending to set up similar programmes.

  11. Influence of Leading-edge Suction on Hydrodynamic and Cavitation Performance of Hydrofoil%前缘抽吸对水翼水动力及空泡性能的影响

    Institute of Scientific and Technical Information of China (English)

    王超; 郭海鹏; 张立新; 郭春雨

    2013-01-01

    为了研究船用水翼前缘抽吸设置对其水动力性能及空泡性能的影响,应用数值模拟的方法进行了系统的计算分析。首先,以NACA0012为研究对象,采用两种湍流模型对翼型绕流进行模拟,通过与实验值对比,确定了合理的湍流模型。随后,计算分析了船用水翼添加前缘抽吸作用后,升力系数、阻力系数和升阻比的变化情况,及对失速角的影响,结果表明船用水翼在前缘布置吸口后可以提高失速角,扩大稳定工作攻角范围,提升翼型升阻比,起到增效的作用。最后,计算了NACA0012翼型及在其前缘加吸口水翼的定常与非定常空泡流动的数值模拟,计算结果表明:定常流动时,在翼型前缘加上吸口,可使空泡尺寸减小,改善了水翼的空泡性能;非定常流动时,加上吸口,可使空泡周期变长,空泡变化范围减小,抑制大规模空泡云的脱落,减少对水翼表面的剥蚀作用,降低空泡对水翼性能的影响。%In order to study the influence of leading-edge suction on hydrodynamic and cavitation performance of hydrofoil, the numerical simulation method is used to calculate and analyze this pro-gram. First, two different turbulence models are used to computer the characteristics of NACA0012 airfoil, and one model is confirmed for the next calculation through comparing the results with tests. Then, the variation of lift coefficient, drag coefficient, lift drag ratio and stalling angle are analyzed while suction inlet is added at leading-edge of hydrofoil. The results show that the suction inlet can increase the stalling angle, enlarge the stable working angle limit, enhance lift drag ratio and improve the efficiency of the hydrofoil. In the end, the steady and unsteady cavitation flow around the NACA0012 airfoil and leading-edge suction hydrofoil are simulated. The results show that the suction inlet can make the cavitation bubble size

  12. Cost to Set up Common Languages

    Science.gov (United States)

    Latora, Vito

    Complexity is a highly interdisciplinary science. Although there are drawbacks for researchers to work at the interface of different fields, such as the cost to set up common languages, and the risks associated with not being recognized by any of the well-established scientific communities, some of my recent work indicates that interdisciplinarity can be extremely rewarding. Drawing on large data sets on scientific production during several decades, we have shown that highly interdisciplinary scholars can outperform specialized ones, and that scientists can enhance their performance by seeking collaborators with expertise in various fields. My vision for complexity is based on the added value of its interdisciplinary nature. I list below three research directions that I am personally eager to explore, and that I think will be among the main challenges of complexity in the next 10 years...

  13. Dermatology referrals in a neurological set up

    Directory of Open Access Journals (Sweden)

    Deeptara Pathak Thapa

    2014-07-01

    Full Text Available Introduction: Dermatology is a specialty, which not only deals with dermatological problems with outpatient but also inpatients referrals. The importances of Dermatologist in hospital setting are rising due to changing condition of medical care. Since no peer-reviewed articles are available for dermatological problems in a neurological set up, we conducted this study to know about pattern of skin disorders in neurological patients. Material and Methods: The present study was a prospective study in a neurological setup, which included data from hospital dermatology consultation request forms over a period of one year. The data included demographic profile of the patient investigation where needed, neurological diagnosis and final dermatological diagnosis. The data was analyzed using SPSS. Results: A total of 285 patients who were requested for consultation were included in the study. Face was the commonest site of involvement (19.6%. Laboratory examination of referred patients revealed abnormal blood counts in 2% cases, renal function tests in 0.7% and urine in 0.4% cases. CT scan showed abnormal findings in 65.6% patients. The most common drug used in these patients was phenytoin (29.1%. The most common dermatological diagnosis was Infection and Infestation (34.7% followed by eczema (46.6%. Drug rash was seen in 3.9% cases. Out of which one had phenytoin induced Steven Johnson syndrome. Skin biopsy was done in 5 patients. Topicals was advised in 80%. Upon discharge 10% of inpatients didn’t require any follow-up. The patients who were followed up after 4 weeks, about 48% had their symptoms resolved with topicals and oral treatment as required. About 38% required more than two follow ups due to chronic course of the diseases. Conclusions: This present study discussed about various manifestations of skin disorders in a neurological set up and emphasizes the role of dermatologist in treating skin problems both in outpatient as well as inpatient

  14. 水力空化联合臭氧氧化灭藻技术的实际应用%Practical Application of Technology Combining Ozonation With Hydrodynamic Cavitation to Algae Removal From Water

    Institute of Scientific and Technical Information of China (English)

    武志林; 王伟民; 李维新; 赵诣; 汤传栋; Giancarlo Cravotto

    2016-01-01

    Based on laboratory research and pilot experiments, an industrial water treatment system combining ozonation with hydrodynamic cavitation has been developed to remove algae from eutrophicated waterbodies. A comparative study was performed to compare the technologies of"complex cavitation/ozone","extrusion cavitation/ozone","suction cavitation/ozone","ozonation alone" and "orifice plate aperture" in water treatment efficiency, relative to chlorophyll a, UV254 , COD and NH3-N contents and turbidity in treated water. Meanwhile, comparison was done between"complex cavitation/o-zone" and "ozone alone" in some economic and technological indices, such as ozone utilization rate and net purification rate per unit of ozone and energy consumed. Results show that the technology of "complex cavitation/ozone" reached 44. 5% and 88. 9% in chlorophyll removal rate and 0. 89 and 1. 78 kW·h·m-3 in per unit energy consumption, respec-tively, during the period of stable discharge, when operated at 10 or 5 m3 ·h-1 . Moreover, the indices of turbidity, UV254 and COD all dropped significantly. The two technologies were also found better than the others in the other economic and technical indices. Therefore, it is concluded that the"hydrodynamic cavitation/ozone" system can be applied to quick and effective elimination of algae and chlorophyll, suppression of algal blooms, and reduction of ecological damage and eco-nomic losses that may be caused by algal blooms and dead algae.%在小试和中试试验的基础上,研制了一套水力空化联合臭氧灭藻及净化富营养化水体的工业化水处理系统.在工程运行中,比较了优化条件下复合空化-臭氧、正压空化-臭氧、抽吸空化-臭氧和单独臭氧氧化工艺以及孔板孔径对水体中叶绿素a、浊度、UV254、COD以及氨氮等的处理效果.同时,还对复合空化-臭氧和单独臭氧氧化工艺的臭氧利用率、臭氧和单位能耗的净化效率等经济技术指标进行了比

  15. Seminar on setting up your own business

    CERN Multimedia

    DSU Department

    2008-01-01

    Organised by the French-Swiss Foundation for Research and Technology (FFRST), in partnership with CERN, and open to all CERN personnel: Friday 7 March 2008, from 9.00 a.m. to 4.00 p.m. in the Globe of Science and Innovation Are you interested in setting up your own business? Have you already taken any steps in that direction? Do you wish to develop a business plan based on your own professional expertise? If so, you are cordially invited to take part in this seminar, at which you will have the opportunity to: hear first-hand accounts from former members of the CERN personnel who have become entrepreneurs and talk about their experience and needs in terms of financial support, find out about the possibilities for obtaining support at the national level (in Switzerland and France) through presentations of the CTI Start-up and OSEO programmes, have discussions with the relevant Swiss and French regional authorities responsible for supporting start-ups in innovative technolog...

  16. Seminar on setting up your own business

    CERN Multimedia

    DSU Department

    2008-01-01

    Organised by the French-Swiss Foundation for Research and Technology (FFRST), in partnership with CERN, and open to all CERN personnel: Friday 7 March 2008, from 9.00 a.m. to 4.00 p.m. in the Globe of Science and Innovation Are you interested in setting up your own business? Have you already taken any steps in that direction? Do you wish to develop a business plan based on your own professional expertise? If so, then you are cordially invited to take part in this seminar at which you will have the opportunity to: hear first-hand accounts from former members of the CERN personnel who have become entrepreneurs and talk about their experience and needs in terms of financial support, find out about the possibilities of obtaining support at national level (in Switzerland and France) through presentations of the CTI Start-up and OSEO programmes, have discussions with the relevant Swiss and French regional authorities responsible for supporting start-ups in innovative technologies...

  17. Platform for setting up interactive virtual environments

    Science.gov (United States)

    Souza, Danilo; Dias, Paulo; Santos, Daniel; Sousa Santos, Beatriz

    2014-02-01

    This paper introduces pSIVE, a platform that allows the easy setting up of Virtual Environments, with interactive information (for instance, a video or a document about a machine that is present in the virtual world) to be accessed for different 3D elements. The main goal is to create for evaluation and training on a virtual factory - but generic enough to be applied in different contexts by non-expert users (academic and touristic for instance). We show some preliminary results obtained from two different scenarios: first a production line of a factory with contextualized information associated to different elements which aimed the training of employees. Second a testing environment, to compare and assess two different selection styles that were integrated in pSIVE and to allow different users to interact with an environment created with pSIVE to collect opinions about the system. The conclusions show that the overall satisfaction was high and the comments will be considered in further platform development.

  18. Setting up of holographic optical tweezer arrays

    Science.gov (United States)

    Gupta, Deepak K.; Tata, B. V. R.; Ravindran, T. R.

    2017-05-01

    Optical tweezers use tightly focused laser beams to hold and move microscopic objects in a solvent. However, many applications require simultaneous control over multitude of particles, positioning them in 3D space at desired locations with desired symmetry, which is made possible by the use of holographic optical tweezers using the technique of beam shaping and holography. We have designed and developed a holographic optical tweezer set-up using a phase only liquid crystal, reflective spatial light modulator. We employ the technique of phase modulation to modulate the phase of the beam by generating holograms using Random Superposition (RS) and weighted Gerchberg Saxton algorithm (WGS) algorithm for generating desired patterns of light at the trapping plane. A 4×4 array of beams with square symmetry was generated using WGS algorithm and trapped polystyrene particles of size 1.2 micron in a 4×4 two dimensional array. There were uniformity issues among the trap intensities, as we move away from the zeroth order spot. This was corrected by taking into account diffraction effects due to the pixelated nature of SLM modulating the intensity of the trap spots and the ghost order suppression by spatial disorder.

  19. Dynamic behaviors of cavitation bubble for the steady cavitating flow

    Institute of Scientific and Technical Information of China (English)

    Jun CAI; Xiulan HUAI; Xunfeng LI

    2009-01-01

    In this paper, by introducing the flow velocity item into the classical Rayleigh-Plesset dynamic equation, a new equation, which does not involve the time term and can describe the motion of cavitation bubble in the steady cavitating flow, has been obtained. By solving the new motion equation using Runge-Kutta fourth order method with adaptive step size control, the dynamic behaviors of cavitation bubble driven by the varying pressure field downstream of a venturi cavitation reactor are numerically simulated. The effects of liquid temperature (corre-sponding to the saturated vapor pressure of liquid), cavitation number and inlet pressure of venturi on radial mo-tion of bubble and pressure pulse due to the radial motion are analyzed and discussed in detail. Some dynamic behaviors of bubble different from those in previous papers are displayed. In addition, the internal relationship between bubble dynamics and process intensification is also discussed. The simulation results reported in this work reveal the variation laws of cavitation intensity with the flow conditions of liquid, and will lay a foundation for the practical application of hydrodynamic cavitation technology.

  20. Some Cavitation Properties of Liquids

    Directory of Open Access Journals (Sweden)

    K. D. Efremova

    2016-01-01

    Full Text Available Cavitation properties of liquid must be taken into consideration in the engineering design of hydraulic machines and hydro devices when there is a possibility that in their operation an absolute pressure in the liquid drops below atmospheric one, and for a certain time the liquid is in depression state. Cold boiling, which occurs at a comparatively low temperature under a reduced absolute pressure within or on the surface of the liquid is regarded as hydrostatic cavitation if the liquid is stationary or as hydrodynamic cavitation, if the liquid falls into conditions when in the flow cross-section there is a sharply increasing dynamic pressure and a dropping absolute pressure.In accordance with the theory of cavitation, the first phase of cavitation occurs when the absolute pressure of the degassed liquid drops to the saturated vapour pressure, and the air dissolved in the liquid, leaving the intermolecular space, is converted into micro-bubbles of combined air and becomes a generator of cavitation “nuclei”. A quantitative estimate of the minimum allowable absolute pressure in a real, fully or partially degassed liquid at which a hydrostatic cavitation occurs is of practical interest.Since the pressure of saturated vapour of a liquid is, to a certain extent, related to the forces of intermolecular interaction, it is necessary to have information on the cavitation properties of technical solutions, including air solution in a liquid, as a solute may weaken intermolecular bonds and affect the pressure value of the saturated solvent vapour. In the experiment to carry out vacuum degassing of liquids was used a hydraulic air driven vacuum pump.The paper presents hydrostatic and hydrodynamic degassing liquid processes used in the experiment.The experimental studies of the cavitation properties of technical liquids (sea and distilled water, saturated NaCl solution, and pure glycerol and as a 49/51% solution in water, mineral oil and jet fuel enabled

  1. Visualization of cavitation bubbles; Visualisation de bulles de cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Chouvellon, M.; Fournel, Th.; Ducottet, Ch. [Universite Jean Monnet, 31 Saint-Etienne (France). Laboratoire Traitement du Signal et Instrumentation-UMR CNRS 5516

    1999-07-01

    A high frequency ultrasonic reactor allows the degradation of some organic compounds which are not or poorly biodegradable by usual methods in industrial flows. The propagation of an ultrasonic wave in a liquid induces cavitation phenomena. The implosion of cavitation bubble locally causes a temperature of about several thousand Kelvins and a pressure of about several hundred bars. Such conditions allow the creation of the hydroxyl radicals and then the oxidation of organic compounds. The aim of this paper is to describe the method used to visualize cavitation bubbles in an ultrasonic reactor at a frequency of 500 kHz. The experimental set-up and the measurement of both the bubble radius and the fringe separation are presented. (authors)

  2. Numerical Prediction of Unsteady Behavior of Cavitating Flow on Hydrofoils using Bubble Dynamics Cavitation Model

    Directory of Open Access Journals (Sweden)

    Nur-E- Mostafa

    2016-01-01

    Full Text Available This paper presents a numerical study with pressure-based finite volume method for prediction of non-cavitating and time dependent cavitating flow on hydrofoil. The phenomenon of cavitation is modeled through a mixture model. For the numerical simulation of cavitating flow, a bubble dynamics cavitation model is used to investigate the unsteady behavior of cavitating flow and describe the generation and evaporation of vapor phase. The non-cavitating study focuses on choosing mesh size and the influence of the turbulence model. Three turbulence models such as Spalart-Allmaras, Shear Stress Turbulence (SST k-ω model and Re-Normalization Group (RNG k-ε model with enhanced wall treatment are used to capture the turbulent boundary layer on the hydrofoil surface. The cavitating study presents an unsteady behavior of the partial cavity attached to the foil at different time steps for σ=0.8. Moreover, this study focuses on cavitation inception, the shape and general behavior of sheet cavitation, lift and drag forces for different cavitation numbers. Finally, the flow pattern and hydrodynamic characteristics are also studied at different angles of attack.

  3. Simulations of Steady Cavitating Flow in a Small Francis Turbine

    Directory of Open Access Journals (Sweden)

    Ahmed Laouari

    2016-01-01

    Full Text Available The turbulent flow through a small horizontal Francis turbine is solved by means of Ansys-CFX at different operating points, with the determination of the hydrodynamic performance and the best efficiency point. The flow structures at different regimes reveal a large flow eddy in the runner and a swirl in the draft tube. The use of the mixture model for the cavity/liquid two-phase flow allowed studying the influence of cavitation on the hydrodynamic performance and revealed cavitation pockets near the trailing edge of the runner and a cavitation vortex rope in the draft tube. By maintaining a constant dimensionless head and a distributor vane opening while gradually increasing the cavitation number, the output power and efficiency reached a critical point and then had begun to stabilize. The cavitation number corresponding to the safety margin of cavitation is also predicted for this hydraulic turbine.

  4. How To Set Up Your Own Small Business. Study Guide.

    Science.gov (United States)

    American Inst. of Small Business, Minneapolis, MN.

    This study guide is intended for use with the separately available entrepreneurship education text "How To Set Up Your Own Business." The guide includes student exercises that have been designed to accompany chapters dealing with the following topics: determining whether or not to set up a small business, doing market research, forecasting sales,…

  5. Numerical 3D flow simulation of attached cavitation structures at ultrasonic horn tips and statistical evaluation of flow aggressiveness via load collectives

    Science.gov (United States)

    Mottyll, S.; Skoda, R.

    2015-12-01

    A compressible inviscid flow solver with barotropic cavitation model is applied to two different ultrasonic horn set-ups and compared to hydrophone, shadowgraphy as well as erosion test data. The statistical analysis of single collapse events in wall-adjacent flow regions allows the determination of the flow aggressiveness via load collectives (cumulative event rate vs collapse pressure), which show an exponential decrease in agreement to studies on hydrodynamic cavitation [1]. A post-processing projection of event rate and collapse pressure on a reference grid reduces the grid dependency significantly. In order to evaluate the erosion-sensitive areas a statistical analysis of transient wall loads is utilised. Predicted erosion sensitive areas as well as temporal pressure and vapour volume evolution are in good agreement to the experimental data.

  6. Cavitation bioeffects.

    Science.gov (United States)

    Kimmel, Eitan

    2006-01-01

    Acoustic cavitation takes place when tiny gas bubbles oscillate, grow, and collapse in liquid under the influence of ultrasonic field. This study reviews cavitation bioeffects that are found both in vivo and in vitro when exposed to either low- or high-power acoustics. Proposed mechanisms are discussed here as well based on theoretical studies, simulations and test bench experiments. Bioeffects are induced in living tissue once the gas bubble is, for instance, within a blood vessel in close vicinity to the endothelium or to the red blood cells. Conditions for inducing various bioeffects are discussed - from severe damage, such as cell necrosis, to delicate alterations, such as increased permeability of cell membrane. Present and potential applications for therapeutic purpose from stone pulverization and tissue ablation to gene transfection and transdermal delivery are reviewed including the growing use of artificial microbubbles.

  7. Cavitating behaviour analysis of Darrieus-type cross flow water turbines

    Energy Technology Data Exchange (ETDEWEB)

    Aumelas, V; Pellone, C; MaItre, T, E-mail: vivien.aumelas@hmg.inpg.f [Equipe Energetique, Grenoble-INP - LEGI (Laboratory of Geophysical and Industrial Flows) Domaine Universitaire - BP 53, Grenoble cedex 9, 38041 (France)

    2010-08-15

    The aim of this paper is to study the cavitating behaviour of bare Darrieus-type turbines. For that, the RANS code CAVKA, has been used. Under non-cavitating conditions, the power coefficient and the thrusts calculated with CAVKA are compared to experimental values obtained in the LEGI hydrodynamic tunnel. Under cavitating conditions, for several cavitation numbers, the numerical power coefficients and vapour structures are compared to experimental ones. Different blade profiles and camber lines are also studied for non-cavitating and cavitating conditions.

  8. Cavitating behaviour analysis of Darrieus-type cross flow water turbines

    Science.gov (United States)

    Aumelas, V.; Pellone, C.; Maître, T.

    2010-08-01

    The aim of this paper is to study the cavitating behaviour of bare Darrieus-type turbines. For that, the RANS code CAVKA, has been used. Under non-cavitating conditions, the power coefficient and the thrusts calculated with CAVKA are compared to experimental values obtained in the LEGI hydrodynamic tunnel. Under cavitating conditions, for several cavitation numbers, the numerical power coefficients and vapour structures are compared to experimental ones. Different blade profiles and camber lines are also studied for non-cavitating and cavitating conditions.

  9. Rotating Cavitation Supression Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FTT proposes development of a rotating cavitation (RC) suppressor for liquid rocket engine turbopump inducers. Cavitation instabilities, such as rotating...

  10. Cavitation Nuclei: Experiments and Theory

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2009-01-01

    The Swedish astrophysicist and Nobel Prize winner Hannes Alfven said: Theories come and go - the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory...... becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer...... us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories - and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character....

  11. CAVITATION NUCLEI: EXPERIMENTS AND THEORY

    Institute of Scientific and Technical Information of China (English)

    MфRCH K. A.

    2009-01-01

    The Swedish astrophysicist and Nobel Prize winner Hannes Alfvén said: Theories come and go ─ the experiment is here forever. Often a theory, which we set up to describe an observed physical phenomenon, suffers from the lack of knowledge of decisive parameters, and therefore at best the theory becomes insufficient. Contrary, the experiment always reveals nature itself, though at prevailing experimental conditions. With essential parameters being out of control and even maybe unidentified, apparently similar experiments may deviate way beyond our expectations. However, these discrepancies offer us a chance to reflect on the character of the unknown parameters. In this way non-concordant experimental results may hold the key to the development of better theories – and to new experiments for the testing of their validity. Cavitation and cavitation nuclei are phenomena of that character.

  12. French scientists offered time to set up companies

    CERN Multimedia

    Butler, D

    1999-01-01

    The French minister of national education, research and technology announced that French researchers working for public research institutes and universities are to be offered up to six years sabbatical leave to set up their own companies (11 para)

  13. Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins

    Directory of Open Access Journals (Sweden)

    Mohamed Adel

    2011-08-01

    Full Text Available Abstract Purpose The purpose of the study was to evaluate the patient set-up error of different anatomical sites, to estimate the effect of different frequencies of online verifications on the patient set-up accuracy, and to calculate margins to accommodate for the patient set-up error (ICRU set-up margin, SM. Methods and materials Alignment data of 148 patients treated with inversed planned intensity modulated radiotherapy (IMRT or three-dimensional conformal radiotherapy (3D-CRT of the head and neck (n = 31, chest (n = 72, abdomen (n = 15, and pelvis (n = 30 were evaluated. The patient set-up accuracy was assessed using orthogonal megavoltage electronic portal images of 2328 fractions of 173 planning target volumes (PTV. In 25 patients, two PTVs were analyzed where the PTVs were located in different anatomical sites and treated in two different radiotherapy courses. The patient set-up error and the corresponding SM were retrospectively determined assuming no online verification, online verification once a week and online verification every other day. Results The SM could be effectively reduced with increasing frequency of online verifications. However, a significant frequency of relevant set-up errors remained even after online verification every other day. For example, residual set-up errors larger than 5 mm were observed on average in 18% to 27% of all fractions of patients treated in the chest, abdomen and pelvis, and in 10% of fractions of patients treated in the head and neck after online verification every other day. Conclusion In patients where high set-up accuracy is desired, daily online verification is highly recommended.

  14. Cavitation for improved sludge conversion into biogas

    Science.gov (United States)

    Stoop, A. H.; Bakker, T. W.; Kramer, H. J. M.

    2015-12-01

    In several studies the beneficial influence of pre-treatment of waste activated sludge with cavitation on the biogas production was demonstrated. It is however, still not fully certain whether this effect should be mainly contributed to an increase in conversion rate of organics into biogas by anaerobic bacteria, and how much cavitation increases the total biogas yield. An increase in yield is only the case if cavitation can further disrupt otherwise inaccessible cell membrane structures and long chain organic molecules. In this study the influence of hydrodynamic cavitation on sludge that was already digested for 30 days was investigated. The total biogas yield could indeed be increased. The effect of the backpressure behind the venturi tube on the yield could not yet be established.

  15. 航行器垂直入水空泡特性与流体动力研究%Research on Cavitation and Hydrodynamic of Vertical Water- Entry for Supercavitating Vehicles

    Institute of Scientific and Technical Information of China (English)

    胡平超; 张宇文; 袁绪龙

    2011-01-01

    Study on caviting shape and hydrodynamic on vertical water - entry of supercavitating vehicles.Based on standard k - ε model, the unsteady cavity character in a longitudinal gravity force field was numerically simulated by using 3D dynamic mesh technique during the supercavitating vehicle vertical enter water.Result shows that the angle of attack is larger, the asymmetry of the cavity is more obvious, the cavity of the confronted stream surface is shorter and thinner, the cavity of the opposing stream surface is longer and thicker, and the time difference of the closed cavity of the confronted and the opposing stream surface is longer.The angle of attack is larger, the hydrodynamic coefficient is larger; at the same water - entry depth, the slop of the drag coefficient curve is approximate equivalent at different angle of attack, and the slop of the lift coefficient curve and the pitching moment coefficient curve is larger with a larger angle of attack.The result can be used for research on water - entry trajectory.%研究超空泡航行器垂直入水空泡形态与流体动力特性,针对空泡出现流体动力特性改变,为了确定入水参数,根据标准k-E模型,采用三维动网格技术,对超空泡航行器入水过程重力场下非定常空泡特性以及流体动力参数进行了数值仿真.得出结果,攻角越大,空泡形态不对称性越明显,迎流面空泡越短越薄,背流面空泡越长越厚,迎流面与背流面的空泡闭合时差越大,且流体动力系数越大.证明对同-入水深度时,从曲线上分析,阻力系数的斜率基本一致,升力系数与俯仰力矩系数的斜率随攻角的增大而增大.研究结果可为入水弹道的研究提供了流体动力参数.

  16. FOREWORD: International Symposium of Cavitation and Multiphase Flow (ISCM 2014)

    Science.gov (United States)

    Wu, Yulin

    2015-01-01

    The International Symposium on Cavitation and Multiphase Flow (ISCM 2014) was held in Beijing, China during 18th-21st October, 2014, which was jointly organized by Tsinghua University, Beijing, China and Jiangsu University, Zhenjiang, China. The co-organizer was the State Key Laboratory of Hydroscience and Engineering, Beijing, China. Cavitation and multiphase flow is one of paramount topics of fluid mechanics with many engineering applications covering a broad range of topics, e.g. hydraulic machinery, biomedical engineering, chemical and process industry. In order to improve the performances of engineering facilities (e.g. hydraulic turbines) and to accelerate the development of techniques for medical treatment of serious diseases (e.g. tumors), it is essential to improve our understanding of cavitation and Multiphase Flow. For example, the present development towards the advanced hydrodynamic systems (e.g. space engine, propeller, hydraulic machinery system) often requires that the systems run under cavitating conditions and the risk of cavitation erosion needs to be controlled. The purpose of the ISCM 2014 was to discuss the state-of-the-art cavitation and multiphase flow research and their up-to-date applications, and to foster discussion and exchange of knowledge, and to provide an opportunity for the researchers, engineers and graduate students to report their latest outputs in these fields. Furthermore, the participants were also encouraged to present their work in progress with short lead time and discuss the encountered problems. ISCM 2014 covers all aspects of cavitation and Multiphase Flow, e.g. both fundamental and applied research with a focus on physical insights, numerical modelling and applications in engineering. Some specific topics are: Cavitating and Multiphase Flow in hydroturbines, pumps, propellers etc. Numerical simulation techniques Cavitation and multiphase flow erosion and anti-erosion techniques Measurement techniques for cavitation and

  17. STUDY UPON THE CAVITATION PHENOMENON OF THE ROTORS

    Directory of Open Access Journals (Sweden)

    Beazit ALI

    2011-11-01

    Full Text Available The main problem of the hydrodynamics of cavitation implosion of a single bubble, consists inpressure and velocity fields determination, including the collapse velocity of the bubble wall. By analysis thetheoretic and experimental phenomenon it establish the implicit function which describes this phenomenon. Byapplication the  theorem for this implicit function it finds the criterion equation of phenomenon.Depending on operating condition various cavitation patterns can be observed on a body surface astravelling bubbles, attached sheet cavitation, shear cavitation or vortex cavitation. Leading edge attachedpartialcavitation is commonly encountered on rotor blades or on hydrofoil. It corresponds to the case for whichavapor cavity is attached in the vecinity of the leading edge and extends over a fraction of the foil surface. Itgenerally takes places at incidence angles for which a leading edge pressure peak occurs and reduced belowtheliquid vapor pressure. At the early phases of development, leading edge partial cavitation is steady.

  18. DISCOVERY AND ANALYSIS ON CAVITATION IN PIEZOELECTRIC PUMPS

    Institute of Scientific and Technical Information of China (English)

    Zhang Jianhui; Xia Qixiao; Lai Dehua; Onuki Akiyoshi; Hong Zhen

    2004-01-01

    The contributing factors for the cavitation in piezoelectric pumps are analyzed,theoretically, and the device fitting for observing and recording is set up. With it the experiments are carried out to observe the emergence and the flowing of the cavitations in the piezoelectric pumps. According to the statistic and the analysis to the data of the experiments, the peculiar features are discovered. These features are composed of balls-amassing, center-more, and flow-out.

  19. Microbubble Cavitation Imaging

    OpenAIRE

    Vignon, Francois; Shi, William T; Powers, Jeffry E.; Everbach, E. Carr; Liu, Jinjin; Gao, Shunji; Xie, Feng; Porter, Thomas R.

    2013-01-01

    Ultrasound cavitation of microbubble contrast agents has a potential for therapeutic applications such as sonothrombolysis (STL) in acute ischemic stroke. For safety, efficacy, and reproducibility of treatment, it is critical to evaluate the cavitation state (moderate oscillations, stable cavitation, and inertial cavitation) and activity level in and around a treatment area. Acoustic passive cavitation detectors (PCDs) have been used to this end but do not provide spatial information.

  20. Set-up for lifetime measurements with the DSA method

    Energy Technology Data Exchange (ETDEWEB)

    Avrigeanu, V.; Bucurescu, D.; Ivascu, M.; Osvath, E.; Popescu, D.; Stog, O.

    1975-01-01

    A set-up for the measurement of short nuclear lifetimes at the IAP U-120 cyclotron, by means of the Doppler shift attenuation method (DSAM) is described. A 100 mm diameter reaction chamber is used, with a transparent window which allows visualization of the beam spot on the target. The electronic block scheme is discussed. As a test measurement for this set-up the determination of the lifetime of the first 2/sup +/ state in /sup 30/Si by means of the /sup 27/Al(..cap alpha..,p..gamma..)/sup 30/Si reaction is presented. 5 figures.

  1. Synchronized passive imaging of single cavitation events

    Science.gov (United States)

    Gateau, Jérôme; Aubry, Jean-François; Pernot, Mathieu; Chauvet, Daurian; Boch, Anne-Laure; Fink, Mathias; Tanter, Mickaël

    2011-09-01

    Passive cavitation detection techniques are usually of relatively low sensitivity to single cavitation events. Moreover, a single-element transducer is generally used, so that the spatial localization of these cavitation events is not possible, or is limited to the probing volume. To both detect and localize single cavitation events over an extended volume, the following experimental set-up has been used and validated: cavitation is induced with a focused single-element transducer (mean frequency 660 kHz, f♯ = 1) driven by a high power (up to 5 kW) electric burst of a few cycles, and the acoustic emission of the bubbles is recorded on a standard linear array (4-7 MHz), mounted on the side of the single element to probe its focal spot. Both the frequencies and the geometry used are appropriate to in vivo implementation. The recording of ultrasonic radio-frequency (RF) data was performed simultaneously on 64 channels of the array and was synchronized with the pulsed excitation. A single cavitation event results in a high frequency and coherent wave front on the RF data. Thanks to synchronization, these RF data are beam-formed to localize the event with a axial resolution of 0.3 mm. A small number of discrete events could also be separated with this method. Besides, B-mode images obtained with the linear array prior to passive detection allowed the positioning of the events within the tissue structure. This technique has been used first ex vivo on freshly harve pig and sheep thigh muscle: with a two cycle excitation, a 9 MPa cavitation threshold was found. Cavitation detection was also achieved in vivo with a five cycle burst excitation in sheep thigh muscle for a peak acoustic pressure of 11MPa. This technique could provide useful information in order to better understand, control and monitor the initiation phase of the histotripsy process.

  2. Roughness measurement as an alternative method in evaluation of cavitation resistance of steels

    OpenAIRE

    Dojčinović Marina

    2013-01-01

    The purpose of this study was to investigate possible application of roughness measurement in evaluation of resistance of steels in conditions of cavitation effect where these materials are usually applied. Steels which belong to different classes were selected for testing. Cavitation testing was performed by using the ultrasonic vibratory cavitation test set up (stationary specimen method). Mass loss and surface degradation of investigated samples were monitored during the exposure to ...

  3. How To Set Up a Workplace Mentoring System.

    Science.gov (United States)

    Wisconsin Univ., Madison. Center on Wisconsin Strategy.

    This document provides background for those looking to establish workplace mentoring or buddy systems. It touches briefly on the other two legs of an effective workplace preparation program, which are orientation and on-the-job training. These six steps for setting up a mentoring system are described: recruitment, flexibility, training, written…

  4. A Magnetic Set-Up to Help Teach Newton's Laws

    Science.gov (United States)

    Panijpan, Bhinyo; Sujarittham, Thanida; Arayathanitkul, Kwan; Tanamatayarat, Jintawat; Nopparatjamjomras, Suchai

    2009-01-01

    A set-up comprising a magnetic disc, a solenoid and a mechanical balance was used to teach first-year physics students Newton's third law with the help of a free body diagram. The image of a floating magnet immobilized by the solenoid's repulsive force should help dispel a common misconception of students as regards the first law: that stationary…

  5. Xinjiang Region Set Up A New Lead and Zinc Company

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>According to a report from China Nonferrous Metals Network, China Xinjiang Nonferrous Metals Group and Huajin Mining jointly invested RMB600 million yuan to set up a lead and zinc enterprise, Xinjiang Qianxin Mining Co. Ltd. The company, according to Yuan Ze, Chairman of the board leading Xinjiang Nonferrous Met-

  6. View of the WA10 set-up

    CERN Multimedia

    1977-01-01

    The WA10 experiment by the Geneva-Lausanne Collaboration was set-up in the H5 beam (unseparated, up to 50 GeV/c) to study K+-p --> K0pi+-p and other reactions of similar topology, and the energy dependence of resonance production.

  7. Cavitation: Cavitation flow. Citations from the NTIS data base

    Science.gov (United States)

    Habercom, G. E., Jr.

    1980-05-01

    Reports on general aspects of cavitating flow are included. A wide range of theoretical, analytical, and experimental information is presented involving mathematical analysis, computer programs, and testing. Topics include marine engineering, hydrodynamic and aerodynamic configurations, symmetric and nonaxisymmetric shapes, and measuring technology. Data is given on surface piercing struts, helical inducers, pumps, liquid metal systems, and venturi tubes. Applications include dam outlets and spillways, vertical conduits, deep rock drilling, heat pipe stability, water entry, and liquid cryogenic systems. Discussions are made of flow characteristics, noise, nucleate boiling, perturbation problems, and allied subjects. This updated bibliography contains 253 abstracts.

  8. Numerical 3D analysis of cloud cavitation shedding frequency on a circular leading edge hydrofoil with a barotropic cavitation model

    Science.gov (United States)

    Blume, M.; Skoda, R.

    2015-12-01

    A compressible density-based time-explicit low Mach number consistent viscous flow solver is utilised in combination with a barotropic cavitation model for the analysis of cloud cavitation on a circular leading edge (CLE) hydrofoil. For 5° angle of attack, cloud structure and shedding frequency for different cavitation numbers are compared to experimental data. A strong grid sensitivity is found in particular for high cavitation numbers. On a fine grid, a very good agreement with validation data is achieved even without explicit turbulence model. The neglect of viscous effects as well as a two-dimensional set-up lead to a less realistic prediction of cloud structures and frequencies. Comparative simulations with the Sauer-Schnerr cavitation model and modified pre-factors of the mass transfer terms underestimate the measured shedding frequency.

  9. Superhigh Temperatures and Acoustic Cavitation

    CERN Document Server

    Belyaev, V B; Miller, M B; Sermyagin, A V; Topolnikov, A S

    2003-01-01

    The experimental results on thermonuclear synthesis under acoustic cavitation have been analyzed with the account of the latest data and their discussion. The analysis testifies that this avenue of research is a very promising one. The numerical calculations of the D(d, n)^{3}He reaction rate in the deuterated acetone (C_{3}D_{6}O) under the influence of ultrasound depending on T environment temperature within the range T=249-295 K have been carried out within the framework of hydrodynamic model. The results show that it is possible to improve substantially the effect/background relationship in experiments by decreasing the fluid temperature twenty-thirty degrees below zero.

  10. AN EXPERIMENTAL AND NUMERICAL PREDICTION OF MARINE PROPELLER NOISE UNDER CAVITATING AND NON-CAVITATING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Bagheri

    2015-06-01

    Full Text Available In this study, the hydrodynamics and noise prediction of a five blade marine propeller were analyzed through numerical and experimental methods under variety operational conditions. The hydrodynamics of the propeller was studied and the characteristic curves were presented in both numerical and experimental methods. Inception and development of sheet cavitation conditions are obtained in both numerical and experimental methods. The cavitation was started and developed by either increasing the propeller rotational speed in constant pressure or decreasing pressure, while the velocity was kept constant. Good agreements are observed between numerical and experimental results, qualitatively and quantitatively. The noise of the propeller was analyzed through Computational fluid dynamics (CFD method, based on the formulation of Ffowcs Williams and Hawkings (FW-H. Similarly, the experimental results collected from hydrophones were compared with numerical simulations. Finally, the effects of reflection in cavitation tunnel were obtained by considering overall sound pressure levels in numerical and experimental results.

  11. THE WALL EFFECT ON VENTILATED CAVITATING FLOWS IN CLOSED CAVITATION TUNNELS

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin; LU Chuan-jing; LI Jie; PAN Zhan-cheng

    2008-01-01

    For ventilated cavitating flows in a closed water tunnel, the wall effect may exert an important influence on cavity shape and hydrodynamics. An isotropic mixture multiphase model was established to study the wall effect based on the RANS equations,coupled with a natural cavitation model and the RaNG k-ε turbulent model. The governing equations were discrctized using the finite volume method and solved by the Gauss-Seidel linear equation solver on the basis of a segregation algorithm. The algebraic multigrid approach was carried through to accelerate the convergence of solution. The steady ventilated cavitating flows in water tunnels of different diameter were simulated for a conceptual underwater vehicle model which had a disk cavitator. It is found that the choked cavitation number derived is close to the approximate solution of natural cavitating flow for a 3-D disk. The critical ventilation rate falls with decreasing diameter of the water tunnel. However, the cavity size and drag coefficient are rising with the decrease in tunnel diameter for the same ventilation rate, and the cavity size will be much different in water tunnels of different diameter even for the same ventilated cavitation number.

  12. Microbubble cavitation imaging.

    Science.gov (United States)

    Vignon, Francois; Shi, William T; Powers, Jeffry E; Everbach, E Carr; Liu, Jinjin; Gao, Shunji; Xie, Feng; Porter, Thomas R

    2013-04-01

    Ultrasound cavitation of microbubble contrast agents has a potential for therapeutic applications such as sonothrombolysis (STL) in acute ischemic stroke. For safety, efficacy, and reproducibility of treatment, it is critical to evaluate the cavitation state (moderate oscillations, stable cavitation, and inertial cavitation) and activity level in and around a treatment area. Acoustic passive cavitation detectors (PCDs) have been used to this end but do not provide spatial information. This paper presents a prototype of a 2-D cavitation imager capable of producing images of the dominant cavitation state and activity level in a region of interest. Similar to PCDs, the cavitation imaging described here is based on the spectral analysis of the acoustic signal radiated by the cavitating microbubbles: ultraharmonics of the excitation frequency indicate stable cavitation, whereas elevated noise bands indicate inertial cavitation; the absence of both indicates moderate oscillations. The prototype system is a modified commercially available ultrasound scanner with a sector imaging probe. The lateral resolution of the system is 1.5 mm at a focal depth of 3 cm, and the axial resolution is 3 cm for a therapy pulse length of 20 μs. The maximum frame rate of the prototype is 2 Hz. The system has been used for assessing and mapping the relative importance of the different cavitation states of a microbubble contrast agent. In vitro (tissue-mimicking flow phantom) and in vivo (heart, liver, and brain of two swine) results for cavitation states and their changes as a function of acoustic amplitude are presented.

  13. Setting up Individual Loan Facilities for University Students

    Institute of Scientific and Technical Information of China (English)

    XueYong; ZhaoBaohua; DavidKelly

    2004-01-01

    The Chinese state must slash its direct financial allocations to universities and the latter must perform their operations using the annual revenue of tuition fees collected directly from enrolled students. In the same time, state allocations originally earmarked for the campus might be employed to set up a complete loan system to serve students so that each of all qualified enrollees can enjoy an interest-free loan. Students are to be al-

  14. Essential Requirements to Setting up an Aesthetic Practice.

    Science.gov (United States)

    Sachdev, Mukta; Britto, Gillian R

    2014-07-01

    Aesthetic dermatology is becoming a vital and popular branch of medicine. This article aims to guide dermatologists to set up a professional and ethical aesthetic practice. Dermatologists should have an integrated practice of clinical dermatology, dermatosurgery and cosmetic dermatology. Ethical practice is the gold standard for any medical field, especially with dermatologists, who should avoid doing unnecessary procedures. Proper patient counselling and addressing the patients' concerns is imperative.

  15. Change management: setting up an asthma camp for children.

    Science.gov (United States)

    Hodges, Beverly

    This article discusses the process and principles of change management using the example of setting up an asthma camp for children in south Wales. It focuses on the development of an innovative method of educating and caring for children with asthma. The planning, co-ordination, implementation and monitoring of this project through change management are examined, and the importance of evaluation is shown. The article highlights how service delivery evolved through assessment of the health and wellbeing needs of children with asthma.

  16. ALBERTA - HEC test beam set-up in June 1999

    CERN Multimedia

    Vinter, M.

    1999-01-01

    Photo1 - HEC 2 (rear) being set up in the "clean" room. Photo2 - HEC 2 (rear) being craned onto rotating C. Photo3 - HEC 2 (rear) being rotated. Photo4 - A now well rotated HEC 2 (rear) is being craned off the C. Photo5 - HEC 2 (rear) installed in the cryostat. Photo6 - Part of the basic frame (the frame that sits in the very bottom of the cryostat). Photo7 - Part of the basic frame (one of the two frames which the 3 calorimeter modules sit on). Photo8 - The marriage frame.

  17. The cold neutron tomography set-up at SINQ

    Science.gov (United States)

    Materna, T.; Baechler, S.; Jolie, J.; Masschaele, B.; Dierick, M.; Kardjilov, N.

    2004-06-01

    The cold neutron tomography station operated at SINQ (Paul Scherrer Institute, Switzerland) is reviewed. The high neutron flux together with a set-up based on a scintillator screen and a CCD camera yielded fast and effective results with resolution down to 250 μm: tomography of small samples (up to 2 cm large) could be performed in less than an hour. The use of a velocity selector improved the contrast discrimination and allows dichromatic tomography. The station is moving to the new research reactor FRM-II (Garching, Germany) where its performances will be increased by the availability of a 5-times-higher cold neutron flux.

  18. Henan Non-ferrous Holding Company Set Up in Henan

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>Henan Non-ferrous Holding Co.(hereinafter referred to as Henan Non-ferrous),an enterprise set up under the joint effort of 3 enterprises with state-owned assets namely Shenhuo Group,Yichuan Power and Yulian Group,has started its operation under tight schedule.The focus of the current operation is acquisition,for which a number of alumina and aluminum processing enterprises are on the list of Henan Non-ferrous.China Nonferrous Metals Monthly reported this news at our last issue,now we try to analysis more details behind the decision.

  19. The cold neutron tomography set-up at SINQ

    OpenAIRE

    Materna, T.; Baechler, Sébastien; Jolie, J; Masschaele, B.; DIERICK, M; Kardjilov, N.

    2005-01-01

    The cold neutron tomography station operated at SINQ (Paul Scherrer Institute, Switzerland) is reviewed. The high neutron flux together with a set-up based on a scintillator screen and a CCD camera yielded fast and effective results with resolution down to 250 μm: tomography of small samples (up to 2 cm large) could be performed in less than an hour. The use of a velocity selector improved the contrast discrimination and allows dichromatic tomography. The station is moving to the new research...

  20. Spectroscopic studies with the PRISMA-CLARA set-up

    Energy Technology Data Exchange (ETDEWEB)

    Fioretto, E; Corradi, L; Angelis, G de; Napoli, D R; Sahin, E; Silvestri, R; Stefanini, A M; Valiente-Dobon, J J [INFN - Laboratori Nazionali di Legnaro, Viale dell' Universita 2, Legnaro (PD), I-35020 (Italy); Bazzacco, D; Beghini, S; Farnea, E; Lenzi, S M; Lunardi, S; Mason, P; Mengoni, D; Montagnoli, G; Scarlassara, F; Ur, C A [Dipartimento di Fisica dell' Universita di Padova and INFN, Via Marzolo 8, Padova, I-35131 (Italy); Gadea, A [Instituto de Fisica Corpuscolar, CSIC-Universidad de Valencia, Valencia, E-46071 (Spain); Pollarolo, G, E-mail: enrico.fioretto@lnl.infn.i [Dipartimento di Fisica Teorica dell' Universita di Torino and INFN, Via P. Giuria 1, Torino, I-10125 (Italy)

    2010-01-01

    The large solid angle magnetic spectrometer for heavy ions PRISMA, installed at Laboratori Nazionali di Legnaro (LNL), was operated up to the end of March 2008 in conjunction with the highly efficient CLARA set-up. It allowed to carry out nuclear structure and reaction mechanism studies in several mass regions of the nuclide chart. Results obtained in the vicinity of the island of inversion and for the heavy iron and chromium isotopes are presented in this contribution. The status of the new focal plane detectors specifically designed for light ions and slow moving heavy ions is also reported.

  1. Study on cavitation effect of mechanical seals with laser-textured porous surface

    Science.gov (United States)

    Liu, T.; Chen, H. l.; Liu, Y. H.; Wang, Q.; Liu, Z. B.; Hou, D. H.

    2012-11-01

    Study on the mechanisms underlying generation of hydrodynamic pressure effect associated with laser-textured porous surface on mechanical seal, is the key to seal and lubricant properties. The theory model of mechanical seals with laser-textured porous surface (LES-MS) based on cavitation model was established. The LST-MS was calculated and analyzed by using Fluent software with full cavitation model and non-cavitation model and film thickness was predicted by the dynamic mesh technique. The results indicate that the effect of hydrodynamic pressure and cavitation are the important reasons to generate liquid film opening force on LST-MS; Cavitation effect can enhance hydrodynamic pressure effect of LST-MS; The thickness of liquid film could be well predicted with the method of dynamic mesh technique on Fluent and it becomes larger as the increasing of shaft speed and the decreasing of pressure.

  2. Cavitation in Hydraulic Machinery

    Energy Technology Data Exchange (ETDEWEB)

    Kjeldsen, M.

    1996-11-01

    The main purpose of this doctoral thesis on cavitation in hydraulic machinery is to change focus towards the coupling of non-stationary flow phenomena and cavitation. It is argued that, in addition to turbulence, superimposed sound pressure fluctuations can have a major impact on cavitation and lead to particularly severe erosion. For the design of hydraulic devices this finding may indicate how to further limit the cavitation problems. Chapter 1 reviews cavitation in general in the context of hydraulic machinery, emphasizing the initial cavitation event and the role of the water quality. Chapter 2 discusses the existence of pressure fluctuations for situations common in such machinery. Chapter 3 on cavitation dynamics presents an algorithm for calculating the nucleation of a cavity cluster. Chapter 4 describes the equipment used in this work. 53 refs., 55 figs.,10 tabs.

  3. Standard guidelines for setting up a dermatosurgery theatre

    Directory of Open Access Journals (Sweden)

    Rajendran S

    2009-08-01

    Full Text Available Introduction, definition, rationale and scope: Dermatologists in India are now increasingly performing surgical and cosmetic procedures in their practice. This calls for minimum standards at the national level with the main focus of patient safety and hence the guidelines for setting up a dermatosurgical theatre. Facility: The dermatosurgery theatre can be created in either physician′s clinic, or a hospital depending on the procedure to be performed. The dermatosurgery theatre requires careful planning with regards to - location, dimension, shell design, lighting, electrical requirements, operation table, chair, trolley, surgical instruments, sterilization of devices, asepsis and advanced life support. Apart from physical considerations, other considerations including theatre etiquettes, consent for surgery, safety of dermatosurgeon, theatre staff and lastly biomedical waste management should be looked into. These issues are discussed in detail in the recommendations.

  4. The new cold neutron tomography set-up at SINQ

    CERN Document Server

    Baechler, S; Cauwels, P; Dierick, M; Jolie, J; Materna, T; Mondelaers, W

    2002-01-01

    A new cold neutron tomography set-up is operational at the neutron spallation source SINQ of the Paul Scherrer Institute (PSI) in Villigen, Switzerland. The detection system is based on a sup 6 LiF/ZnS:Ag conversion screen and a CCD camera. Several tests have been carried out to characterize the quality of the tomography system, such as homogeneity, reproducibility, L/D-ratio and spatial resolution. The high flux and the good efficiency of the detector lead to very short exposure times. Thus, a typical set of tomography scans can be performed in only 20 min. Then, 3D computed tomography objects were calculated using the filtered back-projection reconstruction method. Initial results of various samples show that cold neutron tomography can be a useful tool for industry, geology and dentistry. Furthermore, suitable applications can be found in the field of archaeology.

  5. The AHIIA experimental set-up for understanding cometary chemistry

    Science.gov (United States)

    Danger, G.; Abou Mrad (Belles-Limeul), N.; Fresneau, A.; Duvernay, F.; Theule, P.; Roussin, G.; Chiavassa, T.

    2014-04-01

    In this contribution, we present the AHIIA experimental system dedicated to the study of chemical reactivity and evolution occurring in comets and asteroids. This experimental set-up is built of three complementary units. The first one based on infrared spectroscopy and mass spectrometry, allows the investigation of reactivity that occur inside cometary ices, while the second unit consists in a gas chromatography - mass spectrometry (GC-MS) directly connected to the ultra vacuum chamber where cometary ice analogs are formed. This unit provides information on volatile organic compounds (VOC) that sublime during the heating of these analogs. The third unit allows the recovery of refractory organic residues formed after the sublimation of all VOC for their ex situ analyses. The AHIIA experimental system provides a complete simulation that could occur in cometary environments.

  6. An unconventional set-up for fluxless brazing of aluminium

    CERN Document Server

    Loos, Robert

    1999-01-01

    In order to successfully braze aluminium alloy assemblies without the use of oxide-removing fluxes, an evironment with very low contaminant level is mandatory. This is mostly achieved by using a vacuum furnace. Brazing under inert gas of sufficient purity is also possible. The method reported upon here makes use of a stainless steel bag which can enter a traditional air furnace. The bag is evacuated, giving a well distributed mechanical pressure on the parts to join. The intrinsic handicap of poor vacuum is compensated by regular inert gas flushing, even at high temperatures. The set-up works rather well, and the idea is believed to yield a valuable strategic and economic option, for the realization of special equipment as well as for prototyping work. We intend to use the principle for the CMS Preshower cooling screens.

  7. Calibration of a Background Oriented Schlieren (BOS) Set-up

    Science.gov (United States)

    Porta, David; Echeverría, Carlos; Cardoso, Hiroki; Aguayo, Alejandro; Stern, Catalina

    2014-11-01

    We use two materials with different known indexes of refraction to calibrate a Background Oriented Schlieren (BOS) experimental set-up, and to validate the Lorenz-Lorentz equation. BOS is used in our experiments to determine local changes of density in the shock pattern of an axisymmetric supersonic air jet. It is important to validate, in particular, the Gladstone Dale approximation (index of refraction close to one) in our experimental conditions and determine the uncertainty of our density measurements. In some cases, the index of refraction of the material is well known, but in others the density is measured and related to the displacement field. We acknowledge support from UNAM through DGAPA PAPIIT IN117712 and the Graduate Program in Mechanical Engineering.

  8. New ESD Test Set-Up for Spacecraft Equipment

    Science.gov (United States)

    Daout, B.; Romero, C.; Pelissou, P.; Wolf, K.-F. J.

    2016-05-01

    The ESD test method according to ECSS-E-ST-20-07C [1] has shown weaknesses in reproducibility and reliability. We have previously shown that test results can vary from one test laboratory and setup to another [2], this entails developing an improved methodology and hardware to address the ECSS test shortcomings. In this paper, a new topology and a generator built using a pressurized high voltage relay, a compensation circuit and a bulk current injection (BCI) probe as a coupling device instead of the 20 cm wire described in the current ECSS standard are presented. The generator and the suggested test set-up have been evaluated in different configurations showing an improved reproducibility and a simpler testing procedure.

  9. Totally endoscopic set-up for mitral valve repair.

    Science.gov (United States)

    Walcot, Nicholas; Hohenberger, Wolfgang; Lakew, Fitsum; Batz, Gerhard; Diegeler, Anno; Perier, Patrick

    2015-01-01

    Minimally invasive mitral surgery is increasingly recognized as routine. We describe here the financially economical set-up for totally endoscopic surgery, which also represents currently the smallest surgical access, limited only by prosthesis and retractor size. This allows the full range of repairs to be performed. Cannulation for cardiopulmonary bypass is performed via the groin. A cosmetic, periareolar (in males) or inframammary fold (in females) incision is made and the chest entered on bypass. An aortic cross-clamp and crystalloid cardioplegia are used via the aortic root prior to atriotomy and surgical repair. This method gives the highest level of cosmesis available and minimal discomfort, without compromising on the extremely good published results.

  10. OPTIMIZING TERRESTRIAL LASER SCANNING MEASUREMENT SET-UP

    Directory of Open Access Journals (Sweden)

    S. Soudarissanane

    2012-09-01

    Full Text Available One of the main applications of the terrestrial laser scanner is the visualization, modeling and monitoring of man-made structures like buildings. Especially surveying applications require on one hand a quickly obtainable, high resolution point cloud but also need observations with a known and well described quality. To obtain a 3D point cloud, the scene is scanned from different positions around the considered object. The scanning geometry plays an important role in the quality of the resulting point cloud. The ideal set-up for scanning a surface of an object is to position the laser scanner in such a way that the laser beam is near perpendicular to the surface. Due to scanning conditions, such an ideal set-up is in practice not possible. The different incidence angles and ranges of the laser beam on the surface result in 3D points of varying quality. The stand-point of the scanner that gives the best accuracy is generally not known. Using an optimal stand-point of the laser scanner on a scene will improve the quality of individual point measurements and results in a more uniform registered point cloud. The design of an optimum measurement setup is defined such that the optimum stand-points are identified to fulfill predefined quality requirements and to ensure a complete spatial coverage. The additional incidence angle and range constraints on the visibility from a view point ensure that individual scans are not affected by bad scanning geometry effects. A complex and large room that would normally require five view point to be fully covered, would require nineteen view points to obtain full coverage under the range and incidence angle constraints.

  11. The use of hydrodynamic disintegration as a means to improve ...

    African Journals Online (AJOL)

    2008-09-15

    Sep 15, 2008 ... Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. ... (ball mill, ultrasonic), oxidation (ozone and hydrogen per- .... American Public Health Association, Wash-.

  12. Setting-up a small observatory from concept to construction

    CERN Document Server

    Arditti, David

    2008-01-01

    Every amateur astronomer who is considering a purpose-built observatory will find this book absolutely invaluable during both the planning and the construction stages. Drawing on David Arditti’s practical experience and that of many other amateur astronomers, it gives invaluable help in making all the important decisions. To begin with, Setting up a Small Observatory addresses what you really need from an observatory, whether to build or buy, what designs you should consider, and where you should site it. Uniquely, it also considers the aesthetics of an amateur observatory: how to make it fit in with your home, garden, and yard, even disguising it as a more common garden building if necessary. There’s also a wealth of practical details for constructing and equipping your small observatory – everything from satisfying local planning laws and building codes through to making sure that your completed observatory is well-equipped, convenient, and comfortable to use. Whether you are considering a simple low-...

  13. Setting up a veterinary medicine skills lab in Germany.

    Science.gov (United States)

    Dilly, Marc; Tipold, Andrea; Schaper, Elisabeth; Ehlers, Jan P

    2014-01-01

    The amendments introduced to the current Veterinary Licensing Ordinance (TAppV) by the Veterinary Licensing Regulation (TAppO) have brought a high degree of skills orientation to fill the gap between academic study and preparing for a wide range of professional skills. In order to improve the veterinary skills of students while conveying fundamental methods in a structured and reproducible way, the University of Veterinary Medicine Hannover, Foundation, has set up the first central veterinary skills lab in Germany. Practical training is provided by means of a three-tier delivery approach. This involves around 40 simulators on an area of approx. 800 m(2) under the guidance of 6-8 staff members, along with supplementary resources such as posters, text instructions and YouTube videos. Since it opened in March 2013, there have been 769 visits to the skills lab and 30,734 hits on YouTube. Initial results show that the skills lab helps to maintain student motivation by teaching them practical skills at an early stage of the basic study-based acquisition of knowledge, whilst reinforcing skills acquisition per se in competence-based teaching. It enables veterinary students to prepare for their first examinations and treatments of live patients in a manner compliant with animal welfare.

  14. Hydrodynamics of Ship Propellers

    DEFF Research Database (Denmark)

    Breslin, John P.; Andersen, Poul

    This book deals with flows over propellers operating behind ships, and the hydrodynamic forces and moments which the propeller generates on the shaft and on the ship hull.The first part of the text is devoted to fundamentals of the flow about hydrofoil sections (with and without cavitation......) and about wings. It then treats propellers in uniform flow, first via advanced actuator disc modelling, and then using lifting-line theory. Pragmatic guidance is given for design and evaluation of performance, including the use of computer modelling.The second part covers the development of unsteady forces...... arising from operation in non-uniform hull wakes. First, by a number of simplifications, various aspects of the problem are dealt with separately until the full problem of a non-cavitating, wide-bladed propeller in a wake is treated by a new and completely developed theory. Next, the complicated problem...

  15. Numerical investigation of cavitation flow in journal bearing geometry

    Science.gov (United States)

    Riedel, M.; Schmidt, M.; Stücke, P.

    2013-04-01

    The appearance of cavitation is still a problem in technical and industrial applications. Especially in automotive internal combustion engines, hydrodynamic journal bearings are used due to their favourable wearing quality and operating characteristics. Cavitation flows inside the bearings reduces the load capacity and leads to a risk of material damages. Therefore an understanding of the complex flow phenomena inside the bearing is necessary for the design development of hydrodynamic journal bearings. Experimental investigations in the fluid domain of the journal bearing are difficult to realize founded by the small dimensions of the bearing. In the recent years more and more the advantages of the computational fluid dynamics (CFD) are used to investigate the detail of the cavitation flows. The analysis in the paper is carried out in a two-step approach. At first an experimental investigation of journal bearing including cavitation is selected from the literature. The complex numerical model validated with the experimental measured data. In a second step, typically design parameters, such as a groove and feed hole, which are necessary to distribute the oil supply across the gap were added into the model. The paper reflects on the influence of the used design parameters and the variation of the additional supply flow rate through the feed hole regarding to cavitation effects in the bearing. Detailed pictures of the three-dimensional flow structures and the cavitation regions inside the flow film of the bearing are presented.

  16. Cavitation assisted delignification of wheat straw: a review.

    Science.gov (United States)

    Iskalieva, Asylzat; Yimmou, Bob Mbouyem; Gogate, Parag R; Horvath, Miklos; Horvath, Peter G; Csoka, Levente

    2012-09-01

    Wheat is grown in most of the Indian and Chinese regions and after harvesting, the remaining straw offers considerable promise as a renewable source most suitable for papermaking and as a pulping resource. Delignification of wheat straw offers ample scope for energy conservation by way of the application of the process intensification principles. The present work reviews the pretreatment techniques available for improving the effectiveness of the conventional approach for polysaccharide component separation, softening and delignification. A detailed overview of the cavitation assisted delignification process has been presented based on the earlier literature illustrations and important operational guidelines have been presented for overall low-cost and amenable energy utilization in the processes. The effectiveness of the methods has been evaluated according to yield and properties of the isolated fibers in comparison to the conventional treatment. Also the experimental results of one such non-conventional treatment scheme based on the use of hydrodynamic cavitation have been presented for the pulping of wheat straw. The effect of hydrodynamically induced cavitation on cell wall matrix and its components have been characterized using FT-IR analysis with an objective of understanding the cavitation assisted digestion mechanism on straws. It has been observed that the use of hydrodynamic cavitation does not degrade the fibrillar structure of cellulose but causes relocalisation and partial removal of lignin. Overall it appears that considerable improvement can be obtained due to the use of pretreatment or alternate techniques for delignification, which is an energy intensive step in the paper making industries.

  17. SET UP OF THE NEW AUTOMATIC HYDROMETEOROLOGICAL NETWORK IN HUNGARY

    Directory of Open Access Journals (Sweden)

    J. NAGy

    2013-03-01

    Full Text Available The Hungarian Meteorological Service (OMSZ and General Directorate of Water Management (OVF in Hungary run conventional precipitation measurement networks consisting of at least 1000 stations. OMSZ automated its synoptic and climatological network in 90’s and now more than 100 automatic stations give data every 1-10 minutes via GPRS channel. In 2007 the experts from both institutions determined the requirements of a common network. The predecessor in title of OVF is general Directorate for Water and Environment gave a project proposal in 2008 for establishment of a new hydrometeorological network based on common aims for meteorology and hydrology. The new hydrometeorological network was set up in 2012 financed by KEOP project. This network has got 141 weighing precipitation gauges, 118 temperature - humidity sensors and 25 soil moisture and soil temperature instruments. Near by Tisza-Lake two wind sensors have been installed. The network is operated by OMSZ and OVF together. OVF and its institutions maintain the stations itself and support the electricity. OMSZ operates data collection and transmission, maintaines and calibrates the sensors. Using precipitation data of enhanced network the radar precipitation field quality may be more precise, which are input of run-off model. Thereby the time allowance may be increased in flood-control events. Based on soil moisture and temperature water balance in soil may be modelled and forecast can be produced in different conditions. It is very important task in drought and inland water conditions. Considering OMSZ investment project in which new Doppler dual polarisation radar and 14 disdrometers will be installed, the precipitation estimation may be improved since 2015.

  18. An Anticipatory Model of Cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Allgood, G.O.; Dress, W.B., Jr.; Hylton, J.O.; Kercel, S.W.

    1999-04-05

    The Anticipatory System (AS) formalism developed by Robert Rosen provides some insight into the problem of embedding intelligent behavior in machines. AS emulates the anticipatory behavior of biological systems. AS bases its behavior on its expectations about the near future and those expectations are modified as the system gains experience. The expectation is based on an internal model that is drawn from an appeal to physical reality. To be adaptive, the model must be able to update itself. To be practical, the model must run faster than real-time. The need for a physical model and the requirement that the model execute at extreme speeds, has held back the application of AS to practical problems. Two recent advances make it possible to consider the use of AS for practical intelligent sensors. First, advances in transducer technology make it possible to obtain previously unavailable data from which a model can be derived. For example, acoustic emissions (AE) can be fed into a Bayesian system identifier that enables the separation of a weak characterizing signal, such as the signature of pump cavitation precursors, from a strong masking signal, such as a pump vibration feature. The second advance is the development of extremely fast, but inexpensive, digital signal processing hardware on which it is possible to run an adaptive Bayesian-derived model faster than real-time. This paper reports the investigation of an AS using a model of cavitation based on hydrodynamic principles and Bayesian analysis of data from high-performance AE sensors.

  19. Dynamics of Vortex Cavitation

    NARCIS (Netherlands)

    Pennings, P.C.

    2016-01-01

    This thesis describes the mechanisms with which tip vortex cavitation is responsible for broadband pressure fluctuations on ship propellers. Hypotheses for these are described in detail by Bosschers (2009). Validation is provided by three main cavitation-tunnel experiments, one on a model propeller

  20. Numerical Study on Characteristics of 3D Cavitating Hydrofoil

    Directory of Open Access Journals (Sweden)

    Cao Wei

    2015-01-01

    Full Text Available The commercial software ANSYS CFX, APDL and Workbench are applied for modeling the hydrodynamic and structural interactions and characteristics of an elastic hydrofoil by means of a two-way FSI method. The SST (Shear Stress Transport turbulence model and the simplified Rayleigh-Plesset equations are employed for the cavitating flow simulation. Both CFX and APDL solvers are set to be transient. The fluid and solid computational domains are sequentially solved to simulate the interactions between the hydrofoil and the cavitating flow. The results show that the difference in stiffness of common metal materials has trifling effects on hydrofoil performance. But variations in cavitation number and angle of attack will dramatically affect the hydrodynamic and structural interactions and characteristics.

  1. Correlating Inertial Acoustic Cavitation Emissions with Material Erosion Resistance

    Science.gov (United States)

    Ibanez, I.; Hodnett, M.; Zeqiri, B.; Frota, M. N.

    The standard ASTM G32-10 concerns the hydrodynamic cavitation erosion resistance of materials by subjecting them to acoustic cavitation generated by a sonotrode. The work reported extends this technique by detecting and monitoring the ultrasonic cavitation, considered responsible for the erosion process, specifically for coupons of aluminium-bronze alloy. The study uses a 65 mm diameter variant of NPL's cavitation sensor, which detects broadband acoustic emissions, and logs acoustic signals generated in the MHz frequency range, using NPL's Cavimeter. Cavitation readings were made throughout the exposure duration, which was carried out at discrete intervals (900 to 3600 s), allowing periodic mass measurements to be made to assess erosion loss under a strict protocol. Cavitation measurements and erosion were compared for different separations of the sonotrode tip from the material under test. The maximum variation associated with measurement of cavitation level was between 2.2% and 3.3% when the separation (λ) between the transducer horn and the specimen increased from 0.5 to 1.0 mm, for a transducer (sonotrode) displacement amplitude of 43.5 μm. Experiments conducted at the same transducer displacement amplitude show that the mass loss of the specimen -a measure of erosion- was 67.0 mg (λ = 0.5 mm) and 66.0 mg (λ = 1.0 mm).

  2. Cavitating Flow over a Mini Hydrofoil

    Institute of Scientific and Technical Information of China (English)

    LUO Xian-Wu; JI Bin; ZHANG Yao; XU Hong-Yuan

    2012-01-01

    We consider a cavitating flow over a mini hydrofoil (foil profile: Clark-Y-11.7) having a 14 mm chord length in a cavitation tunnel at various cavitation numbers. Experimental observations show that cavitating flows over a miniature hydrofoil display several types of cavitation behavior, such as cavitation inception, sheet cavitation, cloud cavitation and super cavitation with the decreasing cavitation number. Under the same cavitation conditions, cavitation over a mini hydrofoil would be suppressed in comparison to cavitation over an ordinary hydrofoil. This cavitation scale effect is suspected to be caused by the Reynolds number.%We consider a cavitating flow over a mini hydrofoil (foil profile:Clark-Y-11.7) having a 14mm chord length in a cavitation tunnel at various cavitation numbers.Experimental observations show that cavitating flows over a miniature hydrofoil display several types of cavitation behavior,such as cavitation inception,sheet cavitation,cloud cavitation and super cavitation with the decreasing cavitation number.Under the same cavitation conditions,cavitation over a mini hydrofoil would be suppressed in comparison to cavitation over an ordinary hydrofoil.This cavitation scale effect is suspected to be caused by the Reynolds number.

  3. NONLINEAR PERTURBATION METHOD FOR CALCULATING AXISYMMETRIC CAVITATIONAL FLOWS

    Directory of Open Access Journals (Sweden)

    Vasyl Buivol

    2013-12-01

    Full Text Available A mathematical model of a cavity under the influence of perturbations of various origins is evaluated. The model is based on hydrodynamics of flows with free boundaries and the theory of small perturbations. Specific analysis is provided for cavitational flows behind cones

  4. Fundamentals of Cavitation

    CERN Document Server

    Franc, Jean-Pierre

    2005-01-01

    The present book is aimed at providing a comprehensive presentation of cavitation phenomena in liquid flows. It is further backed up by the experience, both experimental and theoretical, of the authors whose expertise has been internationally recognized. A special effort is made to place the various methods of investigation in strong relation with the fundamental physics of cavitation, enabling the reader to treat specific problems independently. Furthermore, it is hoped that a better knowledge of the cavitation phenomenon will allow engineers to create systems using it positively. Examples in the literature show the feasibility of this approach.

  5. Instability and breakup of cavitation bubbles within diesel drops

    Institute of Scientific and Technical Information of China (English)

    Ming Lü; Zhi Ning; Kai Yan; Juan Fu; Chunhua Sun

    2015-01-01

    A modified mathematical model is used to study the effects of various forces on the stability of cavitation bubbles within a diesel droplet. The principal finding of the work is that viscous forces of fluids stabilize the cavitation bubble, while inertial force destabilizes the cavitation bubble. The droplet viscosity plays a dominant role on the stability of cavitation bubbles compared with that of air and bubble. Bubble–droplet radius ratio is a key factor to control the bubble stability, especially in the high radius ratio range. Internal hydrodynamic and surface tension forces are found to stabilize the cavitation bubble, while bubble stability has little relationship with the external hydrodynamic force. Inertia makes bubble breakup easily, however, the breakup time is only slightly changed when bubble growth speed reaches a certain value (50 m·s−1). In contrast, viscous force makes bubble hard to break. With the increasing initial bubble–droplet radius ratio, the bubble growth rate increases, the bubble breakup radius decreases, and the bubble breakup time becomes shorter.

  6. An Automated Ac Susceptibility Set up Fabricated Using a Closed-Cycle Helium Refrigerator

    CERN Document Server

    Kundu, S

    2011-01-01

    We have described here the design and operation of an automated ac susceptibility set up using a closed cycle helium refrigerator. This set up is useful for measuring linear and nonlinear magnetic susceptibilities of various magnetic materials. The working temperature range is 2 K to 300 K. The overall sensitivity of the set up is found to be 10-3 emu.

  7. Cavitation guide for control valves

    Energy Technology Data Exchange (ETDEWEB)

    Tullis, J.P. [Tullis Engineering Consultants, Logan, UT (United States)

    1993-04-01

    This guide teaches the basic fundamentals of cavitation to provide the reader with an understanding of what causes cavitation, when it occurs, and the potential problems cavitation can cause to a valve and piping system. The document provides guidelines for understanding how to reduce the cavitation and/or select control valves for a cavitating system. The guide provides a method for predicting the cavitation intensity of control valves, and how the effect of cavitation on a system will vary with valve type, valve function, valve size, operating pressure, duration of operation and details of the piping installation. The guide defines six cavitation limits identifying cavitation intensities ranging from inception to the maximum intensity possible. The intensity of the cavitation at each limit Is described, including a brief discussion of how each level of cavitation influences the valve and system. Examples are included to demonstrate how to apply the method, including making both size and pressure scale effects corrections. Methods of controlling cavitation are discussed providing information on various techniques which can be used to design a new system or modify an existing one so it can operate at a desired level of cavitation.

  8. Cavitation in medicine.

    Science.gov (United States)

    Brennen, Christopher Earls

    2015-10-06

    We generally think of bubbles as benign and harmless and yet they can manifest the most remarkable range of physical effects. Some of those effects are the stuff of our everyday experience as in the tinkling of a brook or the sounds of breaking waves at the beach. But even these mundane effects are examples of the ability of bubbles to gather, focus and radiate energy (acoustic energy in the above examples). In other contexts that focusing of energy can lead to serious technological problems as when cavitation bubbles eat great holes through ships' propeller blades or cause a threat to the integrity of the spillways at the Hoover Dam. In liquid-propelled rocket engines, bubbles pose a danger to the stability of the propulsion system, and in artificial heart valves they can cause serious damage to the red blood cells. In perhaps the most extraordinary example of energy focusing, collapsing cavitation bubbles can emit not only sound, but also light with black body radiation temperatures equal to that of the sun (Brennen 1995 Cavitation and bubble dynamics). But, harnessed carefully, this almost unique ability to focus energy can also be put to remarkably constructive use. Cavitation bubbles are now used in a remarkable range of surgical and medical procedures, for example to emulsify tissue (most commonly in cataract surgery or in lithotripsy procedures for the reduction of kidney and gall stones) or to manipulate the DNA in individual cells. By creating cavitation bubbles non-invasively thereby depositing and focusing energy non-intrusively, one can generate minute incisions or target cancer cells. This paper will begin by briefly reviewing the history of cavitation phenomena and will end with a vision of the new horizons for the amazing cavitation bubble.

  9. EFFECTS OF ENTRAINED AIR MANNER ON CAVITATION DAMAGE*

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LUO Chao

    2011-01-01

    Early in 1953 the experiments by Peterka proved that air entrainment has effects on decreasing cavitation damage. This technology has been widely used in the release works of high dams since the inception of air entrainment in the Grand Goulee Dam in 1960. Behavior, mechanism and application of air entrainment for cavitation damage control have been investigated for over half century. However, severe cavitation damage happened due to complex mechanism of air entrainment. The effects of air entrainment are related to many factors, including geometric parameters, hydraulic parameters and entrained air manners. In the present work an experimental set-up for air entrainment was specially designed, the behavior of reducing cavitation damage was experimentally investigated in the three aspects of entrained air pressure, air tube aera and air tube number. The results show that magnitude of reduction of cavitation damage is closely related to the entrained air tube number as well as entrained air pressure, air tube aera, and that the effect through three air tubes is larger than that through single air tube although the entrained air tubes have the same sum of tube aera, that is, 1 + 1 + 1 > 3. Therefore, it is important to design an effective manner of air entrainment.

  10. Biological Effects of Acoustic Cavitation

    Science.gov (United States)

    2007-11-02

    rectified diffusion. 56 III. STABLE CAVITATION A. Introduction There are manv areas associated with the biological effects of ultrasound in which the...used said as cavitation indicators. Further, if clinical ultrasound systems are found to be inducing cavitation , either stable or transient, it will...O BIOLOGICAL EFFECTS OF ACOUSTIC CAVITATION by Lawrence A. Crum -- Physical Acoustics Research Laboratory Department of Physics and Astronomy ’ CTE

  11. A novel ultrasonic cavitation enhancer

    NARCIS (Netherlands)

    Fernandez Rivas, David; Verhaagen, Bram; Galdamez Perez, Andres; Castro-Hernandez, Elena; Zwieten, van Ralph; Schroen, Karin

    2015-01-01

    We introduce a Cavitation Intensifying Bag as a versatile tool for acoustic cavitation control. The cavitation activity is spatially controlled by the modification of the inner surface of the bag with patterned pits of microscopic dimensions. We report on different measurements such as the transmiss

  12. A novel ultrasonic cavitation enhancer

    NARCIS (Netherlands)

    Rivas, Fernandez D.; Verhaagen, B.; Galdamez Perez, Andres; Castro-Hernandez, Elena; Zwieten, Van Ralph; Schroen, Karin

    2015-01-01

    We introduce a Cavitation Intensifying Bag as a versatile tool for acoustic cavitation control. The cavitation activity is spatially controlled by the modification of the inner surface of the bag with patterned pits of microscopic dimensions. We report on different measurements such as the transm

  13. Acoustic cavitation movies

    Science.gov (United States)

    Crum, Lawrence A.

    2003-04-01

    Acoustic cavitation is a phenomenon that occurs on microsecond time scales and micron length scales, yet, it has many macroscopic manifestations. Accordingly, it is often difficult, at least for the author, to form realistic physical descriptions of the specific mechanisms through which it expresses itself in our macroscopic world. For example, there are still many who believe that cavitation erosion is due to the shock wave that is emitted by bubble implosion, rather than the liquid jet created on asymmetric collapse...and they may be right. Over the years, the author has accumulated a number of movies and high-speed photographs of cavitation activity, which he uses to form his own visual references. In the time allotted, he will show a number of these movies and photographs and discuss their relevance to existing technological problems. A limited number of CDs containing the presented materials will be available to interested individuals. [Work supported in part by the NIH, USAMRMC, and the ONR.

  14. Cavitation in liquid helium

    Energy Technology Data Exchange (ETDEWEB)

    Finch, R. D.; Kagiwada, R.; Barmatz, M.; Rudnick, I.

    1963-11-15

    Ultrasonic cavitation was induced in liquid helium over the temperature range 1.2 to 2.3 deg K, using a pair of identical transducers. The transducers were calibrated using a reciprocity technique and the cavitation threshold was determined at 90 kc/s. It was found that this threshold has a sharp peak at the lambda point, but is, at all temperatures quite low, with an approximate range of 0.001 to 0.01 atm. The significance of the results is discussed. (auth)

  15. Taming Acoustic Cavitation

    CERN Document Server

    Rivas, David Fernandez; Enriquez, Oscar R; Versluis, Michel; Prosperetti, Andrea; Gardeniers, Han; Lohse, Detlef

    2012-01-01

    In this fluid dynamics video we show acoustic cavitation occurring from pits etched on a silicon surface. By immersing the surface in a liquid, gas pockets are entrapped in the pits which upon ultrasonic insonation, are observed to shed cavitation bubbles. Modulating the driving pressure it is possible to induce different behaviours based on the force balance that determines the interaction among bubbles and the silicon surface. This system can be used for several applications like sonochemical water treatment, cleaning of surfaces with deposited materials such as biofilms.

  16. Numerical investigation of the hydroelastic response in cavitating flow around a flexible hydrofoil

    Science.gov (United States)

    Wu, Q.; Huang, B.; Wang, G. Y.; Wang, J. D.

    2015-01-01

    The objective of this paper is to investigate the hydroelastic response of cavitating flows around a flexible hydrofoil. The numerical simulations are performed by solving the incompressible and unsteady Reynolds Average Navier-Stokes (URANS) equations via the commercial CFD software ANSYS CFX. The k-ω SST turbulence model with the turbulence viscosity correction and the Kubota cavitation model are introduced to the present simulations. The results showed that the cavitation has significantly affected the foil deformation and the evolution of the transient cavity shape and the corresponding hydrodynamic response with time can be divided into three stages: during the development of the attached cavity, the cavity formed on the suction side of the flexible hydrofoil is much larger with a steeper slope of the cavity area, which is caused by the increase of the effective angle of attack due to the twist deformation. During the vortex-cavitation interaction process, the hydrodynamic loads for the rigid hydrofoil remain relatively flat, while that for the flexible hydrofoil fluctuates with high frequency because of the foil deformation, leading to a more complex cavitation pattern due to the interaction with the foil vibration. During the cavity shedding process, both the primary and the residual cavities shed downstream totally, together with the counter-rotational vortex structures, corresponding to a sharp drop in the hydrodynamic loads. The larger effective angle of attack leads to the advanced cavity inception of the next cavitation period.

  17. Cavitation Instabilities in Inducers

    Science.gov (United States)

    2006-11-01

    gas handling turbomachines . The fluctuation of the cavity length is plotted in Fig.8 under the surge mode oscillation vi . The major differences...Cavitation Instabilities of Turbomachines .” AIAA Journal of Propulsion and Power, Vol.17, No.3, 636-643. [5] Tsujimoto, Y., (2006), “Flow Instabilities in

  18. Cavitation during wire brushing

    Science.gov (United States)

    Li, Bo; Zou, Jun; Ji, Chen

    2016-11-01

    In our daily life, brush is often used to scrub the surface of objects, for example, teeth, pots, shoes, pool, etc. And cleaning rust and stripping paint are accomplished using wire brush. Wire brushes also can be used to clean the teeth for large animals, such as horses, crocodiles. By observing brushing process in water, we capture the cavitation phenomenon on the track of moving brush wire. It shows that the cavitation also can affect the surface. In order to take clear and entire pictures of cavity, a simplified model of one stainless steel wire brushing a boss is adopted in our experiment. A transparent organic tank filled with deionized water is used as a view box. And a high speed video camera is used to record the sequences. In experiment, ambient pressure is atmospheric pressure and deionized water temperature is kept at home temperature. An obvious beautiful flabellate cavity zone appears behind the moving steel wire. The fluctuation of pressure near cavity is recorded by a hydrophone. More movies and pictures are used to show the behaviors of cavitation bubble following a restoring wire. Beautiful tracking cavitation bubble cluster is captured and recorded to show.

  19. Acoustic cavitation and sonochemistry

    NARCIS (Netherlands)

    Stricker, L.

    2013-01-01

    Sonochemistry is the use of cavitation for achieving a chemical conversion. When microbubbles are driven in the nonlinear regime, localized extreme temperatures (up to 10000 K) and pressures (up to 1000 bar) can be reached upon collapse, the surrounding liquid remaining ambient,thus giving origin to

  20. Ozone and Cavitation Combination

    Science.gov (United States)

    Carreon, Ernestina; Traversoni, Leonardo

    2009-09-01

    From laboratory measurements it is well known that the addition of ozone and cavitation enhances the properties of both, understanding for that the ones related to disinfection and carbon removal from waste water. This paper shows modeling of such phenomena that gives some light to the understanding of it and also provides the opportunity to improve the effectiveness of the current procedures.

  1. Numerical Modeling of Unsteady Cavitating Flows around a Stationary Hydrofoil

    Directory of Open Access Journals (Sweden)

    Antoine Ducoin

    2012-01-01

    Full Text Available The objective of this paper is to evaluate the predictive capability of three popular transport equation-based cavitation models for the simulations of partial sheet cavitation and unsteady sheet/cloud cavitating flows around a stationary NACA66 hydrofoil. The 2D calculations are performed by solving the Reynolds-averaged Navier-Stokes equation using the CFD solver CFX with the k-ω SST turbulence model. The local compressibility effect is considered using a local density correction for the turbulent eddy viscosity. The calculations are validated with experiments conducted in a cavitation tunnel at the French Naval Academy. The hydrofoil has a fixed angle of attack of α=6° with a Reynolds number of Re = 750,000 at different cavitation numbers σ. Without the density modification, over-prediction of the turbulent viscosity near the cavity closure reduces the cavity length and modifies the cavity shedding characteristics. The results show that it is important to capture both the mean and fluctuating values of the hydrodynamic coefficients because (1 the high amplitude of the fluctuations is critical to capturing the extremes of the loads to ensure structural safety and (2 the need to capture the frequency of the fluctuations, to avoid unwanted noise, vibrations, and accelerated fatigue issues.

  2. An indigenously developed electronic control system for Langmuir-Blodgett film deposition set-up

    Indian Academy of Sciences (India)

    C P Navathe; B L Dashora; Archana Jaiswal; D S Thakur; U N Roy; L M Kukreja

    2001-06-01

    An indigenous and simple electronic control system for Langmuir-Blodgett (LB) film deposition set-up has been developed. This set-up consists of a microstepping circuit to drive the stepper motors with precision and smooth motion, essential for controlled movement of the barriers and substrate in the LB set-up. Linear variable differential transformer (LVDT)-based displacement measuring device has been developed and used to measure the surface pressure of the monolayer material spread on the water surface. A control program is written which incorporates all operational modes required to drive the set-up and to acquire the data in situ using a set of user-friendly commands. This control set-up has been successfully used to plot the pressure-area isotherm of various amphiphilic compounds such as ferric stearate, zinc arachidate etc. and for deposition of ordered LB films of ferric stearate.

  3. Implicit large eddy simulation of unsteady cloud cavitation around a plane- convex hydrofoil

    Institute of Scientific and Technical Information of China (English)

    罗先武; 季斌

    2015-01-01

    The present paper focuses on the erosive cavitation behavior around a plane convex hydrofoil. The Zwart-Gerber-Belamri cavitation model is implemented in a library form to be used with the OpenFOAM. The implicit large eddy simulation (ILES) is app- lied to analyze the three dimensional unsteady cavitating flow around a plane convex hydrofoil. The numerical results in the cases under the hydrodynamic-conditions, which were experimentally tested at the high speed cavitation tunnel of the École Polytechnique Fédérale de Lausanne (EPFL), clearly show the sheet cavitation development, the shedding and the collapse of vapor clouds. It is noted that the cavitation evolutions including the maximum vapor length, the detachment and the oscillation frequency, are captured fairly well. Furthermore, the pressure pulses due to the cavitation development as well as the complex vortex structures are reasona- bly well predicted. Consequently, it may be concluded that the present numerical method can be used to investigate the unsteady cavitation around hydrofoils with a satisfactory accuracy.

  4. Research on Cavitation Regions of Upstream Pumping Mechanical Seal Based on Dynamic Mesh Technique

    Directory of Open Access Journals (Sweden)

    Huilong Chen

    2014-08-01

    Full Text Available In order to study the cavitation area of the Upstream Pumping Mechanical Seal, three-dimensional microgap inner flow field of the Upstream Pumping Mechanical Seal was simulated with multiphase flow cavitation model and dynamic mesh technique based on hydrodynamic lubrication theory. Furthermore, the simulated result was compared with the experimental data. The results show that the simulated result with the Zwart-Gerber-Belamri cavitation model was much closer to the experimental data. The area of cavitation inception mainly occurred at the concave side of the spiral groove and surrounding region without spiral grooves, which was nearly covered by the inner diameter to roots of grooves; in addition, the region near the surface of the stationary ring was primary cavitation location. The area of cavitation has little relationship with the medium pressure; however, it became larger following increasing rotating speed in the range of researched operating conditions. Moreover the boundary of cavitated area was transformed from smooth to rough, which occurred in similar film thickness. When cavitation number was decreasing, which was conducive to improving the lubrication performance of sealed auxiliary, it made the sealing stability decline.

  5. PREFACE: 9th International Symposium on Cavitation (CAV2015)

    Science.gov (United States)

    Farhat, M.; Müller, A.

    2015-12-01

    It is our pleasure and privilege to welcome all the participants of the 9th International Symposium on Cavitation (CAV2015) to Lausanne. Since its initiation in 1986 in Sendai, Japan, the CAV symposium has grown to become the world's foremost event dedicated to cavitation. Hosted by EPFL (Ecole Polytechnique Fédérale de Lausanne) and staged at the SwissTech Convention Center, CAV2015 is a unique opportunity to exchange with leading scientists and industry experts about the latest advances in theoretical modelling, numerical simulation and experimentation related to cavitation phenomena with a special emphasis on practical applications. The topics covered by CAV2015 include cavitation in ¬fluid machinery and fuel systems, bubble dynamics, cavitation erosion, advanced numerical simulation, sonochemistery, biomedicine and experimental techniques. CAV2015 will also host an exhibition of leading providers of state of the art measurement equipment, including high-speed imaging systems, non-intrusive velocimetry, pressure sensors, as well as numerical solvers. We have accepted over 190 papers, which will be presented in four parallel sessions. The proceedings will appear in the open access Journal of Physics: Conference Series (JPCS), which is part of the IOP Conference Series. All published papers are fully citable and upon publication will be free to download in perpetuity. We would like to thank all the reviewers for their great help during the selection process. We will also propose six plenary speakers to highlight cavitation issues in different fields. Finally, we would like to warmly thank our sponsors for their valuable support and the local Organizing Committee for the efforts in setting up this important event. We look forward to seeing you in Lausanne!

  6. A CFD Study on the Mechanisms Which Cause Cavitation in Positive Displacement Reciprocating Pumps

    Institute of Scientific and Technical Information of China (English)

    Aldo Iannetti; Matthew T. Stickland; William M. Dempster

    2015-01-01

    A transient multiphase CFD (computational fluid dynamics) model was set up to investigate the main causes which lead to cavitation in PD (positive displacement) reciprocating pumps. Many authors agree on distinguishing two different types of cavitation affecting PD pumps: flow induced cavitation and cavitation due to expansion. The flow induced cavitation affects the zones of high fluid velocity and consequent low static pressure e.g. the valve-seat volume gap while the cavitation due to expansion can be detected in zones where the decompression effects are important e.g. in the vicinity of the plunger. This second factor is a distinctive feature of PD pumps since other devices such as centrifugal pumps are only affected by the flow induced type. Unlike what has been published in the technical literature to date, where analysis of positive displacement pumps are based exclusively on experimental or analytic methods, the work presented in this paper is based entirely on a CFD approach, it discusses the appearance and the dynamics of these two phenomena throughout an entire pumping cycle pointing out the potential of CFD techniques in studying the causes of cavitation and assessing the consequent loss of performance in positive displacement pumps.

  7. Characteristics of Vibration Induced by Cavitation

    Institute of Scientific and Technical Information of China (English)

    WANG Guo-yu; TAO Lei; LIU Shu-yan; QIAN Jian-jun

    2005-01-01

    Cavitation-induced vibration characteristics and the relations between the vibration and cavitation are studied. Cavitation vibrations are measured around a model hollow-jet valve by an accelerometer under cavitating and non-cavitating conditions. The measurement data is analyzed by FFT method. The corresponding cavitating flow patterns are photographed by a high-speed camera with an xenon flash lamp. The frequency band of the vibration induced by cavitation is determined. To compare the vibration intensities under different cavitation conditions, a definition of vibration acceleration level is introduced based on power spectral density of the vibration. By the analysis of vibration, the definitions of characteristic cavitation number are suggested. According to these cavitation numbers, the cavitation process is divided into three stages, that is, incipient cavitation, subcavitation and supercavitation.

  8. PENURUNAN WAKTU SET-UP UNTUK PENINGKATAN EFEKTIFITAS PADA PT. X

    Directory of Open Access Journals (Sweden)

    Hendri Hendri

    2015-06-01

    Full Text Available PT. X bergerak dalam industri manufuktur yang memproduksi komponen otomotif yang  salah satu prosesnya adalah pembuatan bearing. Saat ini, persaingan dalam dunia bisnis semakin ketat. Situasi ini membuat organisasi untuk memperbaiki diri dengan penurunan waktu set-up supaya dapat menghilangkan pemborosan sehingga peningkatan efektifitas dapat dicapai. Untuk melakukan penurunan waktu set-up dalam penelitian ini menggunakan metode Single Minute Exchange of Dies (SMED. SMED adalah salah satu metoda improvement dari Lean Manufacturing yang digunakan untuk mempercepat waktu yang dibutuhkan untuk melakukan setup pergantian dari memproduksi satu jenis produk ke model produk lainnya. Penelitian ini bertujuan untuk mengetahui waktu Set up, serta mengetahui cara memperbaiki dan menurunkan waktu set up. Setelah dilakukan penelitian diketahui total waktu set up atau change over serta dilakukan perbaikan pada tiga titik yakni memindakan enam aktivitas internal menjadi aktivitas eksernal yang aktivitasnya dipersingkat, mengganti cara kerja setting/pengencangan baut dari cara manual ke alat bantu pengencangan dengan bantuan tekanan udara (pneumatic, dan mengganti cara kerja setting/penyetelan manual menjadi penyetelan dengan mengunakan block gauge. Secara keseluruhan terjadi penurunan waktu set up yang signifikan. Dengan demikian terjadi peningkatan efektifitas dengan menghilangkan pemborosan waktu set up sehinga terjadi peningkatan jumlah produksi per jam.

  9. Shock Waves in Cloud Cavitation

    OpenAIRE

    Brennen, C. E.; Reisman, G. E.; Wang, Y.-C.

    1997-01-01

    Thie paper described experimental and computational investigations of the dynamics of clouds of cavitation bubbles. Recent studies have confirmed that the interactions between bubbles as they are manifest in the dynamics of bubble clouds lead to generation of very large impulsive pressures which, in turn, cause substantial enhancement of the radiated noise and the material damage which results from this form of cavitation. The experimental program focuses on cloud cavitation formed on th...

  10. A novel ultrasonic cavitation enhancer

    OpenAIRE

    Rivas, Fernandez D.; Verhaagen, B.; Galdamez Perez, Andres; Castro-Hernandez, Elena; Zwieten, van, D.M.; Schroen, Karin

    2015-01-01

    We introduce a Cavitation Intensifying Bag as a versatile tool for acoustic cavitation control. The cavitation activity is spatially controlled by the modification of the inner surface of the bag with patterned pits of microscopic dimensions. We report on different measurements such as the transmission of ultrasound, temperature increase inside the bag during sonication. Several applications of interest to other scientific activities are also demonstrated.

  11. Techniques of Ultrasound Cavitation Control

    Directory of Open Access Journals (Sweden)

    S. P. Skvortsov

    2015-01-01

    Full Text Available The control methods of ultrasonic cavitation applied now within the range from 20 kHz to 80 kHz use either control of ultrasound source parameters (amplitude, acoustic power, etc. or control of one of the cavitation effects (erosion of materials, sonoluminescence, power of acoustic noise, etc.. These methods provide effective management of technological processes, however, make it impossible to relate the estimated effect with parameters of pulsations of cavitation bubbles. This is, mainly, due to influence of a number of uncontrollable parameters, in particular, such as temperature, composition of liquid, gas content, etc. as well as because of the difficulty to establish interrelation between the estimated effect and parameters of pulsations. As a result, in most cases it is difficult to compare controlled parameters of ultrasonic cavitation among themselves, and quantitative characteristics of processes become depending on the type of ultrasonic installation and conditions of their measurement.In this regard, methods to determine parameters of bubble pulsations through sounding a cavitation area by low-intensity laser radiation or to record cavitation noise sub-harmonics reflecting dynamics of changing radius of cavitation bubbles are of interest. The method of optical sounding, via the analysis of spectral components of a scattered signal recorded by a photo-detector, allows us to define a phase of the bubbles collapse with respect to the sound wave and a moving speed of the bubbles wall, as well as to estimate a cavitation index within the light beam section.The method to record sub-harmonicas of cavitation noise allows us to define parameters of pulsations, average for cavitation areas.The above methods allow us both to study mechanisms of cavitation action and to form quantitative criteria of its efficiency based on the physical processes, rather than their consequences and are convenient for arranging a feedback in the units using

  12. Methods for Setting up a Three-Dimensional Industrial Surveying System of "Building Blocks Type"

    Institute of Scientific and Technical Information of China (English)

    FENG Wenhao

    2004-01-01

    This paper is to advance some relevant techniques to set up a three-dimensional industrial surveying system of "building blocks type", making use of the electronic theodolite, standard ruler and portable computer.

  13. STUDY OF SETTING UP THE FOREST RESOURCES MANAGEMENT INFORMATION SYSTEM BASED ON WEBGIS

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on an analysis of the characteristics of the Forest Resources Management Information System of each development phase, and consideration of the technical trend in Geographic Information System (GIS) in the Internet Age, this paper explores the importance and the feasibility of setting up Forest Resources Management Information System based on the WEBGIS. At the same time, based on the experience of our study, the paper explores the function, structure and method of developing the Forest Resources Management Information System based on WEBGIS. With the technology of WEBGIS, the Forest Resources Management Information System with data from Huoditang Farm was set up, which makes a great impact on forest resources management. So setting up the Forest Resources Management Information System based on WEBGIS is a trend of forest resources management. In the course of setting up this system, we must pay attention to following questions: 1) unify data standard and information encoding; 2) change mind.

  14. PCE-based vs. distributed set up of bidirectional lightpaths in GMPLS-controlled optical networks

    DEFF Research Database (Denmark)

    Giorgetti, A.; Andriolli, N.; Ruepp, Sarah Renée;

    2010-01-01

    We propose and evaluate a PCE-based architecture for bidirectional lightpath set up in GMPLS-controlled optical networks. The proposed architecture strongly improves the performance of the distributed architecture with both standard and enhanced signaling schemes....

  15. General Formalism for Setting Up Unitary Transform Operators from Classical Transforms via IWOP Technique

    Institute of Scientific and Technical Information of China (English)

    FAN Hong-Yi; HU Shan

    2006-01-01

    We present a general formalism for setting up unitary transform operators from classical transforms via the technique of integration within an ordered product of operators, their normally ordered form can be obtained too.

  16. Setting up a health care quality management system in a multidisciplinary clinical research center

    Directory of Open Access Journals (Sweden)

    L. V. Laktionova

    2013-01-01

    Full Text Available The paper discusses the issues of setting up a quality management system in a multidisciplinary specialized clinical research center. It describes the experience with information technologies used in a prophylactic facility to set up effective out- and inpatient health care control. Measures to optimize work under present-day conditions to upgrade the quality of health care are given using the federal health facility as an example.

  17. A magnetic resonance-compatible experimental set-up for hyperthermia studies.

    Science.gov (United States)

    Jayasundar, R; Hall, L D; Bleehen, N M

    1999-11-01

    This study presents the development and testing of an experimental set-up for simultaneous measurements of pH (intracellular by MR and extracellular by fibre-optic pH meter), tumour bio-energetics (by MR), and core/tumour temperatures (by thermocouples) in tumour-bearing mice. Potential sources of measurement errors when using these techniques concurrently in an MR set-up are discussed. Emphasis is placed on simple practical solutions to these problems.

  18. Accuracy in tangential breast treatment set-up; A portal imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Tienhoven, G. van; Lanson, J.H.; Crabeels, D.; Heukelom, S.; Mijnheer, B.J. (Nederlands Kanker Inst. ' Antoni van Leeuwenhoekhuis' , Amsterdam (Netherlands))

    1991-12-01

    To test accuracy and reproducibility of tangential breast treatment set-up used in The Netherlands Cancer Institute, a portal imaging study was performed in 12 patients treated for early stage breast cancer. With an on-line electronic portal imaging device (EPID) images were obtained of each patient in several fractions and compared with simulator films and with each other. In 5 patients multiple images (on the average 7) per fraction were obtained to evaluate set-up variations due to respiratory movement. The central lung distance (CLD) and other set-up parameters varied within 1 fraction about 1mm (1SD). The average variation of these parameters between various fractions was about 2 mm (1SD). The differences between simulator and treatment set-up over all patients and all fractions was on the average 2-3mm for the central beam edge to skin distance and CLD. It can be concluded that the tangential breast treatment set-up is very stable and reproducible and that respiration does not have a significant influence on treatment volume. EPID appears to be an adequate tool for studies of treatment set-up accuracy like this. (author). 35 refs.; 2 figs.; 3 tabs.

  19. The numerical study of the cavitation-structure interaction around 3D flexible hydrofoil

    Science.gov (United States)

    Shi-liang, Hu; Ying, Chen; Chuan-jing, Lu

    2015-12-01

    The closely coupled approach combined the Finite Volume Method (FVM) solver and the Finite Element Method (FEM) solver is applied to simulation the cavitation-structure interaction of a 3D cantilevered flexible hydrofoil in water tunnel. In the cavitating flow, the elastic hydrofoil would deform or vibrate in bending and twisting mode. And the motion of the foil would affect the characteristics of the cavity and the hydrodynamic load on the foil in turn. With smaller cavitation numbers (σv=2.15), the frequency spectrum of the lift on the foil would contain two frequencies which are associated to the cavity shedding and the first bend frequency of the hydrofoil. With larger cavitation number (σv=2.55), the frequency of the lift is completely dominated by the natural frequency of the foil.

  20. Controlled Cavitation in Microfluidic Systems

    NARCIS (Netherlands)

    Zwaan, Ed; le Gac, Severine; Tsuji, Kinko; Ohl, C.D.

    2007-01-01

    We report on cavitation in confined microscopic environments which are commonly called microfluidic or lab-on-a-chip systems. The cavitation bubble is created by focusing a pulsed laser into these structures filled with a lght-absorbing liquid. At hte center of a 20 mu m thick and 1 mm wide channel,

  1. NUMERICAL SIMULATIONS OF CAVITATING FLOWS

    Institute of Scientific and Technical Information of China (English)

    Wu Lei

    2003-01-01

    A new model, which involves viscous and multi-phase effects, was given to study cavitating flows. A local compressible model was established by introducing a density-pressure function to account for the two-phase flow of water/vapor and the transition from one phase to the other. An algorithm for calculating variable-density N-S equations of cavitating flow problem was put forward. The present method yields reasonable results for both steady and unsteady cavitating flows in 2D and 3D cases. The numerical results of unsteady character of cavitating flows around hydrofoils coincide well with experimental data. It indicates the feasibility to apply this method to a variety of cavitating flows of practical problems.

  2. Equipment set-up among Olympic sprint and slalom kayak paddlers.

    Science.gov (United States)

    Ong, K B; Ackland, T R; Hume, P A; Ridge, B; Broad, E; Kerr, D A

    2005-01-01

    The anthropometry and equipment set-up for sprint (31 male; 11 female) and slalom (12 male; 12 female) kayak paddlers who competed at the 2000 Olympic Games in Sydney were measured in the 15 day period before competition. This paper provides normative data for equipment set-up in these sports, as well as information about differences in rigging and paddle dimensions between sprint and slalom kayak paddlers. These differences were consistent for both male and female athletes, with sprint paddlers seated higher and using longer paddles with longer, though narrower, blades (p < 0.0001). Among male sprint paddlers, only minor differences in equipment set-up were found between competitors ranked in the top 10 places compared to the rest of the field. Considering all male paddlers initially, then sprint paddlers alone, significant (p < 0.01) regression equations were developed for the prediction of foot bar distance (r2 = 0.482 and 0.589 respectively) and hand grip distance (r2 = 0.400 and 0.541 respectively). The process of fine tuning equipment set-up often requires hours of practice with subjective feedback from the athlete. The normative data presented in this paper should assist coaches with this process as their athletes evolve toward their individual optimum set-up.

  3. Mathematical Model of the Electronuclear Set-Up on the Beam of the JINR Synchrotron

    CERN Document Server

    Barashenkov, V S; Kumawat, H; Lobanova, V A

    2004-01-01

    On the base of the Monte Carlo code CASCADE, developed at JINR, a mathematical model of the deep-subcritical set-up with uranium blanket used in experiments underway at JINR using a 0.6-4 GeV proton beam, is created. The neutron spectra, yields and energies of generated particles are calculated and compared for several modifications of the set-up. The influence of paraffin and graphite moderators on the characteristics of particles escaping lead target is studied. The modelled set-up can be considered as a first step to experiments with the designed at JINR U-Pu ADS SAD with heat power of several tens of kW.

  4. Mapping of cavitational activity in a pilot plant dyeing equipment.

    Science.gov (United States)

    Actis Grande, G; Giansetti, M; Pezzin, A; Rovero, G; Sicardi, S

    2015-11-01

    C). Different liquid flow rates were tested to investigate the effect of the hydrodynamics characterising the equipment. The mapping of the cavitation intensity in the pilot-plant machinery was performed to achieve with the following goals: (a) to evaluate the influence of turbulence on the cavitation intensity, and (b) to determine the optimal distance from the ultrasound device at which a fabric should be positioned, this parameter being a compromise between the cavitation intensity (higher next to the transducer) and the US field uniformity (achieved at some distance from this device). By carrying out dyeing tests of wool fabrics in the prototype unit, consistent results were confirmed by comparison with the mapping of cavitation intensity.

  5. Circulation of groundwater due to wave set-up on a permeable beach

    Directory of Open Access Journals (Sweden)

    Stanis³aw R. Massel

    2001-09-01

    Full Text Available Sandy beaches are highly exploited but very dynamic and fragile environments. Driven by waves, the water flow through the beach body is able to transport oxygen, and hence help to maintain biological activity in the porous media. The paper presents a theoretical attempt to predict the groundwater circulation due to wave set-up. Two systems of circulations have been discovered, related to two different gradients of the set-up height. For the offshore gradient, the horizontal excess pressure gradient induces flow in the offshore direction. However, closer to the shore, the pressure gradient is reversed and the resulting flow moves shorewards.

  6. Set-Up on the Basis of Multiwire Proportional and Ionization Chambers for Radioactive Beam Experiments

    CERN Document Server

    Astabatyan, R A; Kavalov, R L; Kugler, A; Kuznetsov, I V; Kushniruk, V F; Lobastov, S P; Lukyanov, S M; Markaryan, E R; Maslov, V A; Mikhailov, L; Penionzhkevich, Yu E; Poroshin, N O; Skobelev, N K; Smirnov, V I; Sobolev, Yu G; Ugryumov, V Yu

    2002-01-01

    A large-aperture set-up designed for nuclear physics experiments on beams of radioactive nuclei is described. The set-up includes Multiwire Proportional Chamber (MWPC) for measuring the beam profile, MWPC for measuring reaction product angular distributions, a CsI(Tl)-crystal detector and a longitudinal drift ionization chamber for identifying scattered particles and measuring their energy. The results of tests of coordinate MWPCs, particle identification on photon and ion beams, and preliminary measurements of the elastic scattering and the charge exchange reaction of 170 MeV ^{6}He on a CH_{2} target are presented.

  7. Set-up for an optically induced dielectrophoresis platform and its application to micro- and nanoscale material manipulation

    Directory of Open Access Journals (Sweden)

    Yen-Heng Lin

    2014-11-01

    Full Text Available In this study, we set-up an optically induced dielectrophoresis platform, which can be used to manipulate micro- and nanoscale particles. A commercially available liquid-crystal-display–based projector was used as a light source to produce a variety of optical patterns and project them onto a photoconductive material. The optical patterns illuminating the photoconductive material can be used as configurable virtual electrodes, which will induce dielectrophoretic forces on particles. Thus, the particles can be manipulated by dynamic optical patterns. Manipulation of silver nanowires was demonstrated using this platform by forming a specific pattern of nanowires through illumination of the photoconductive chip with an optical pattern. In addition, polystyrene beads with diameters of 10 and 20 μm were also successfully manipulated using this system. By combining the optically induced dielectrophoretic force and the hydrodynamic force, particles of two different sizes can be continuously separated into two different microchannels. Furthermore, the microparticles were collected and concentrated by virtual electrode traps. We believe that this flexible platform can be applied to investigations of a variety of fields.

  8. Dynamic response of cavitating turbomachines

    Science.gov (United States)

    Ng, S. L.

    1976-01-01

    Stimulated by the pogo instability encountered in many liquid propellant rockets, the dynamic behavior of cavitating inducers is discussed. An experimental facility where the upstream and downstream flows of a cavitating inducer could be perturbed was constructed and tested. The upstream and downstream pressure and mass flow fluctuations were measured. Matrices representing the transfer functions across the inducer pump were calculated from these measurements and from the hydraulic system characteristics for two impellers in various states of cavitation. The transfer matrices when plotted against the perturbing frequency showed significant departure from steady state or quasi-steady predictions especially at higher frequencies.

  9. Initial verification of an induction heating set-up for injection molding

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano;

    2013-01-01

    by two thermocouples placed in the die insert. The system was used to heat up the cavity wall with heating rates of up to 10 °C/s. Experiments were carried out with ABS material. The lengths of the object were measured by a suitable measurement set up. The experimental result show that the use...

  10. Optimal clustering of frequency-constrained maintenance jobs with shared set-ups

    NARCIS (Netherlands)

    Dijkhuizen, van Gerhard; Harten, van Aart

    1997-01-01

    Since maintenance jobs often require one or more set-up activities, joint execution or clustering of maintenance jobs is a powerful instrument to reduce shut-down costs. We consider a clustering problem for frequency-constrained maintenance jobs, i.e. maintenance jobs that must be carried out with a

  11. Groundwater flow due to a nonlinear wave set-up on a permeable beach

    Directory of Open Access Journals (Sweden)

    Anna Przyborska

    2014-06-01

    Full Text Available Water flow through the beach body plays an important role in the biological status of the organisms inhabiting the beach sand. For tideless seas, the groundwater flow in shallow water is governed entirely by the surface wave dynamics on the beach. As waves propagate towards the shore, they become steeper owing to the decreasing water depth and at some depth, the waves lose their stability and start to break. When waves break, their energy is dissipated and the spatial changes of the radiation stress give rise to changes in the mean sea level, known as the set-up. The mean shore pressure gradient due to the wave set-up drives the groundwater circulation within the beach zone. This paper discusses the circulation of groundwater resulting from a nonlinear set-up. The circulation of flow is compared with the classic Longuet-Higgins (1983 solution and the time series of the set-up is considered for a 24 h storm. Water infiltrates into the coastal aquifer on the upper part of the beach near the maximum run-up and exfiltration occurs on the lower part of the beach face near the breaking point.

  12. How To Set Up Your Own Small Business. Volumes I-II and Overhead Transparencies.

    Science.gov (United States)

    Fallek, Max

    This two-volume textbook and collection of overhead transparency masters is intended for use in a course in setting up a small business. The following topics are covered in the first volume: getting off to a good start, doing market research, forecasting sales, financing a small business, understanding the different legal needs of different types…

  13. Worms Eat My Garbage. How To Set Up and Maintain a Worm Composting System. First Edition.

    Science.gov (United States)

    Appelhof, Mary

    This book is a resource for parents and teachers who want to teach about recycling and composting by setting up and maintaining a worm composting system. It is designed to be a detailed yet simple manual of vermicomposting. The manual covers the basics of vermicomposting and answers such questions as where to store a composting container, what…

  14. Setting up international biobased commodity trade chains : a guide and 5 examples in Ukraine

    NARCIS (Netherlands)

    Dam, van J.E.G.; Elbersen, W.; Ree, van R.; Wubben, E.F.M.

    2014-01-01

    Setting up biobased production chains, from biomass feedstock to final biobased product (energy, chemicals, materials) is a complicated process in which a whole range of decisions have to be made. Choices include what feedstocks to use, arranging logistics and most important of all the locating faci

  15. Anhui Tongling Invests 1 Billion Yuan to Set up “Copper Industry Fund”

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>On September 12, the signing ceremony for "Anhui Copper Industry Fund" set up by Anhui Tongling Development & Investment Group Co., Ltd. and Shanghai V. Stone Investment Management Co., Ltd. was held in Tongling. The fund is 1 billion yuan.

  16. Lam Kin Chung Morning Sun China- Japan Friendship Fund Set up

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>Lam Kin Chung Morning Sun Charity Fund of HoneKong has decided to donate, from January 2004, 100,000 RMB yuan each year for 5 consecutive years, which totals 500,000 RMB yuan, to set up the Lam Kin Chung Morning Sun China-Japan Friendship Fund under the China Friend-

  17. Setting up and Running a Loss and Bereavement Support Group for Adults with Learning Disabilities

    Science.gov (United States)

    Boyden, Paul; Freeman, Adele; Offen, Liz

    2010-01-01

    Following evidence based literature, the Birmingham Clinical Psychology Service for People with Learning Disabilities ran a Loss and Bereavement Psychotherapy Group. The group consisted of five adults with mild learning disabilities, who met for 8 consecutive weeks. This paper reports the process of setting up a bereavement group for people with…

  18. Four Sides Joined Hands to Set Up Overseas Mining M&A; Fund

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Mining giants including Beijing International Mining City,Beijing International Mining Exchange,Canada Sprott Group,and Shandong Zhaojin Group signed strategic cooperation agreement during the China International Mining Conference 2015,and set up three mining funds.Officials and guests including Zhong Ziran,member of the Party Leadership

  19. Nurse-led clinics: 10 essential steps to setting up a service.

    Science.gov (United States)

    Hatchett, Richard

    This article outlines 10 key steps for practitioners to consider when setting up and running a nurse-led clinic. It lays emphasis on careful planning, professional development and the need to audit and evaluate the service to ensure the clinic is measurably effective.

  20. Key issues in setting up and running a nurse-led cardiology clinic.

    Science.gov (United States)

    Hatchett, Richard

    This article discusses the key issues involved in setting up and running an effective nurse-led cardiology clinic. These include: developing clear aims and objectives for the service, techniques to reduce resistance from colleagues who are affected by the change in service provision, professional development, audit and evaluation.

  1. Design of Testing Set-up for Nuclear Fuel Rod by Neutron Radiography at CARR

    Institute of Scientific and Technical Information of China (English)

    WEI; Guo-hai; HAN; Song-bai; WANG; Hong-li; HAO; Li-jie; WU; Mei-mei; HE; Lin-feng; WANG; Yu; LIU; Yun-tao; SUN; Kai; CHEN; Dong-feng

    2012-01-01

    <正>An experimental set-up dedicated to non-destructively test a 15 cm long pressurized water reactor (PWR) nuclear fuel rod by neutron radiography (NR) is designed and fabricated. It consists of three parts: Transport container, imaging block and steel support. The design of the transport container was optimized with Monte-Carlo simulation by the MCNP code.

  2. Controlling Mechatronic Set-up Using Real-time Linux and CTC ++

    NARCIS (Netherlands)

    Broenink, Johannes F.; Jovanovic, D.S.; Hilderink, G.H.; van Amerongen, J.; Jonker, B.; Regtien, P.; Stramigioli, S.

    2002-01-01

    The development of control software for mechatronic systems is presented by means of a case study: a 2 DOF mechanical rotational set-up usable as a camera-positioning device. The control software is generated using the code generation facility of 20-SIM, thus guaranteeing the generated code being

  3. Experimental Study of Drag Resistance using a Laboratory Scale Rotary Set-Up

    DEFF Research Database (Denmark)

    Weinell, Claus Erik; Olsen, Kenneth N.; Christoffersen, Martin W.;

    2003-01-01

    This work covers an experimental study of the drag resistance of different painted surfaces and simulated large-scale irregularities, viz. dry spraying, weld seams, barnacle fouling and paint remains. A laboratory scale rotary set-up was used to determine the drag resistance, and the surface...

  4. Flow Instabilities in Cavitating and Non-Cavitating Pumps

    Science.gov (United States)

    2006-11-01

    stall and surge may occur in non-cavitating turbomachines at flow rates smaller than design. Rotating stall is a local instability at the...turbomachinery which is basically not dependent on the hydraulic system in which the turbomachine is installed. The stalled region rotates faster than impeller...rate and without significant head decrease. So, it is required to confirm the absence of cavitation instabilities, whenever the turbomachine is

  5. Microleakage of Cavit, CavitW, CavitG and IRM by impedance spectroscopy.

    Science.gov (United States)

    Jacquot, B M; Panighi, M M; Steinmetz, P; G'Sell, C

    1996-07-01

    The aim of this study was to quantify the sealing ability of four temporary filling materials over 9 days using a new electrochemical technique. Fifty-two extracted human maxillary bicuspids were selected and prepared for the measurements. They were divided into four groups of 12 teeth each, in addition to two positive and two negative controls. After preparation of the endodontic access cavity the sealing ability was registered. After a randomization procedure one group was obturated with IRM, another group with Cavit, a third group with CavitW and the last group with CavitG. The sealability was measured just after obturation (time 0) and after days 1, 2, 3, 4, 7 and 9. The results showed that the IRM group was significantly more watertight than the different Cavit formulations. Throughout the experiment no significant difference was noticed between the Cavit and CavitW groups (P > 0.05). The CavitG group was significantly less watertight throughout the measurements (P < 0.05).

  6. Reliable measurement of E. coli single cell fluorescence distribution using a standard microscope set-up.

    Science.gov (United States)

    Cortesi, Marilisa; Bandiera, Lucia; Pasini, Alice; Bevilacqua, Alessandro; Gherardi, Alessandro; Furini, Simone; Giordano, Emanuele

    2017-01-01

    Quantifying gene expression at single cell level is fundamental for the complete characterization of synthetic gene circuits, due to the significant impact of noise and inter-cellular variability on the system's functionality. Commercial set-ups that allow the acquisition of fluorescent signal at single cell level (flow cytometers or quantitative microscopes) are expensive apparatuses that are hardly affordable by small laboratories. A protocol that makes a standard optical microscope able to acquire quantitative, single cell, fluorescent data from a bacterial population transformed with synthetic gene circuitry is presented. Single cell fluorescence values, acquired with a microscope set-up and processed with custom-made software, are compared with results that were obtained with a flow cytometer in a bacterial population transformed with the same gene circuitry. The high correlation between data from the two experimental set-ups, with a correlation coefficient computed over the tested dynamic range > 0.99, proves that a standard optical microscope- when coupled with appropriate software for image processing- might be used for quantitative single-cell fluorescence measurements. The calibration of the set-up, together with its validation, is described. The experimental protocol described in this paper makes quantitative measurement of single cell fluorescence accessible to laboratories equipped with standard optical microscope set-ups. Our method allows for an affordable measurement/quantification of intercellular variability, whose better understanding of this phenomenon will improve our comprehension of cellular behaviors and the design of synthetic gene circuits. All the required software is freely available to the synthetic biology community (MUSIQ Microscope flUorescence SIngle cell Quantification).

  7. Wastewater treatment using hybrid treatment schemes based on cavitation and Fenton chemistry: a review.

    Science.gov (United States)

    Bagal, Manisha V; Gogate, Parag R

    2014-01-01

    Advanced oxidation processes such as cavitation and Fenton chemistry have shown considerable promise for wastewater treatment applications due to the ease of operation and simple reactor design. In this review, hybrid methods based on cavitation coupled with Fenton process for the treatment of wastewater have been discussed. The basics of individual processes (Acoustic cavitation, Hydrodynamic cavitation, Fenton chemistry) have been discussed initially highlighting the need for combined processes. The different types of reactors used for the combined processes have been discussed with some recommendations for large scale operation. The effects of important operating parameters such as solution temperature, initial pH, initial pollutant concentration and Fenton's reagent dosage have been discussed with guidelines for selection of optimum parameters. The optimization of power density is necessary for ultrasonic processes (US) and combined processes (US/Fenton) whereas the inlet pressure needs to be optimized in the case of Hydrodynamic cavitation (HC) based processes. An overview of different pollutants degraded under optimized conditions using HC/Fenton and US/Fenton process with comparison with individual processes have been presented. It has been observed that the main mechanism for the synergy of the combined process depends on the generation of additional hydroxyl radicals and its proper utilization for the degradation of the pollutant, which is strongly dependent on the loading of hydrogen peroxide. Overall, efficient wastewater treatment with high degree of energy efficiency can be achieved using combined process operating under optimized conditions, as compared to the individual process.

  8. Fracture of elastomers by cavitation

    KAUST Repository

    Hamdi, Adel

    2014-01-01

    Cavitation phenomenon is studied in rubber-like materials by combining experimental, theoretical and numerical approaches. Specific tests are carried out on a Styrene Butadiene Rubber to point out main characteristics of cavitation phenomenon. Hydrostatic depression is numerically modelled using finite element method. Numerical results are compared to Ball\\'s and Hou & Abeyaratne\\'s models with regard to cavity nucleation in the material. Both models well fit experimental observations suggesting that the cavitation nucleation in elastomers depends on the confinement degree of the specimen. Finally, critical hydrostatic pressure and critical global deformation are proved to govern cavitation nucleation in the studied material. Critical loadings are identified by comparing experimental and numerical load-displacement curves. © 2013 Elsevier Ltd.

  9. Cavitation inception from bubble nuclei

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2015-01-01

    , and experimental investigations of bubbles and cavitation inception have been presented. These results suggest that cavitation nuclei in equilibrium are gaseous voids in the water, stabilized by a skin which allows diffusion balance between gas inside the void and gas in solution in the surrounding liquid....... The cavitation nuclei may be free gas bubbles in the bulk of water, or interfacial gaseous voids located on the surface of particles in the water, or on bounding walls. The tensile strength of these nuclei depends not only on the water quality but also on the pressure-time history of the water. A recent model......The tensile strength of ordinary water such as tap water or seawater is typically well below 1 bar. It is governed by cavitation nuclei in the water, not by the tensile strength of the water itself, which is extremely high. Different models of the nuclei have been suggested over the years...

  10. Implementation of a combined SAXS/WAXS/QEXAFS set-up for time-resolved in situ experiments

    NARCIS (Netherlands)

    Nikitenko, Sergey; Beale, Andrew M.; van der Eerden, Ad M. J.; Jacques, Simon D. M.; Leynaud, Olivier; O'Brien, Matthew G.; Detollenaere, Dirk; Kaptein, Reinier; Weckhuysen, Bert M.; Bras, Wim

    2008-01-01

    It has previously been shown that there are many benefits to be obtained in combining several techniques in one in situ set-up to study chemical processes in action. Many of these combined set-ups make use of two techniques, but in some cases it is possible and useful to combine even more. A set-up

  11. PRESSURE CHARACTERISTICS OF CAVITATION CONTROL BY AERATION

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; LU Yang-quan; JU Wen-jie; CAI Xin-ming; DING Chun-sheng

    2005-01-01

    This experimental investigation was systematically conducted with the aid of a non-circulating water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology in China.The test velocity is between 20m/s and 40m/s.The least air concentration to prevent cavitation erosion lies between 1.7% and 4.5%.Pressure waveforms with and without aeration in cavitation and cavitation erosion regions were measured.Time-averaged pressure profiles with and without aeration were compared.Pressure characteristics corresponding to least air concentration to prevent cavitation erosion in cavitation and cavitation erosion regions were analyzed.

  12. Relativistic hydrodynamics

    CERN Document Server

    Luciano, Rezzolla

    2013-01-01

    Relativistic hydrodynamics is a very successful theoretical framework to describe the dynamics of matter from scales as small as those of colliding elementary particles, up to the largest scales in the universe. This book provides an up-to-date, lively, and approachable introduction to the mathematical formalism, numerical techniques, and applications of relativistic hydrodynamics. The topic is typically covered either by very formal or by very phenomenological books, but is instead presented here in a form that will be appreciated both by students and researchers in the field. The topics covered in the book are the results of work carried out over the last 40 years, which can be found in rather technical research articles with dissimilar notations and styles. The book is not just a collection of scattered information, but a well-organized description of relativistic hydrodynamics, from the basic principles of statistical kinetic theory, down to the technical aspects of numerical methods devised for the solut...

  13. Servo drive chain evaluation test set-up and configuration methodology

    Directory of Open Access Journals (Sweden)

    R. Heera Singh

    2016-06-01

    Full Text Available The evaluation test bench set-up for servo drive chain consists of various servo sub-modules viz., generic motion controller, servo drive amplifier, brushless AC servo motor, torque coupler, gear reducer and shaft encoder assembly for position feedback is considered. The module interfaces are established for efficient use in commissioning, diagnosing and qualifying the antenna tracking chain. Design methodology demonstrated and specifications of systems were derived. Design specifications of drive chain are configured through software tools for optimizing rate loop and position loop. The transient behaviour and response of servo system using Proportional Integral Derivative controller in time as well in frequency domain is analyzed. Stability conditions are simulated and verified. The test set up energised and test results of different inputs verified and following error minimised by tuning/ optimising the system.

  14. Study of movement coordination in human ensembles via a novel computer-based set-up

    CERN Document Server

    Alderisio, Francesco; Fiore, Gianfranco; di Bernardo, Mario

    2016-01-01

    Movement coordination in human ensembles has been studied little in the current literature. In the existing experimental works, situations where all subjects are connected with each other through direct visual and auditory coupling, and social interaction affects their coordination, have been investigated. Here, we study coordination in human ensembles via a novel computer-based set-up that enables individuals to coordinate each other's motion from a distance so as to minimize the influence of social interaction. The proposed platform makes it possible to implement different visual interaction patterns among the players, so that participants take into consideration the motion of a designated subset of the others. This allows the evaluation of the exclusive effects on coordination of the structure of interconnections among the players and their own dynamics. Our set-up enables also the deployment of virtual players to investigate dyadic interaction between a human and a virtual agent, as well as group synchron...

  15. Development of a grinding-specific performance test set-up

    DEFF Research Database (Denmark)

    Olesen, C. G.; Larsen, B. H.; Andresen, E. L.

    2015-01-01

    and an exponentially rising resistance. A custom-made grinding ergometer was developed with computer-controlled resistance and capable of collecting data during the test. The data collected can be used to find measures of grinding performance such as peak power, time to complete and the decline in repeated grinding......The aim of this study was to develop a performance test set-up for America's Cup grinders. The test set-up had to mimic the on-boat grinding activity and be capable of collecting data for analysis and evaluation of grinding performance. This study included a literature-based analysis of grinding...... demands and a test protocol developed to accommodate the necessary physiological loads. This study resulted in a test protocol consisting of 10 intervals of 20 revolutions each interspersed with active resting periods of 50 s. The 20 revolutions are a combination of both forward and backward grinding...

  16. Construction of a confocal PIXE set-up at the Jozef Stefan Institute and first results

    Energy Technology Data Exchange (ETDEWEB)

    Grlj, N., E-mail: natasa.grlj@ijs.si [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Pelicon, P.; Zitnik, M.; Vavpetic, P. [Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Sokaras, D. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Institute of Nuclear Physics, NCSR ' Demokritos' , GR-15310 Athens (Greece); Karydas, A.G. [Nuclear Spectrometry and Applications Laboratory, International Atomic Energy Agency, A-2444 Seibersdorf (Austria); Institute of Nuclear Physics, NCSR ' Demokritos' , GR-15310 Athens (Greece); Kanngiesser, B. [Institute of Optics and Atomic Physics, Technical University of Berlin, Hardenbergstrasse 36, D-10623 Berlin (Germany)

    2011-10-15

    A new confocal PIXE set-up at the Jozef Stefan Institute in Ljubljana was recently designed and built. It consists of a silicon-drift detector, a specially designed polycapillary lens and a snout-alignment interface for precise positioning. It allows detector movement in all directions and therefore precise alignment during the creation of the probing volume and the possibility of simultaneous use of other complementary techniques, including standard {mu}-PIXE measurements with another X-ray detector. A description of the new set-up is given, as well as a short presentation of the method itself. Two custom-designed types of X-ray lenses were tailored and manufactured for this application, a standard semi-lens and a polycapillary conic collimator; both were characterized and compared within the scope of development of the confocal PIXE system. First results of depth profiling with the beam scanning mode are shown.

  17. Investigation on Superior Performance by Fractional Controller for Cart-Servo Laboratory Set-Up

    Directory of Open Access Journals (Sweden)

    Ameya Anil Kesarkar

    2014-01-01

    Full Text Available In this paper, an investigation is made on the superiority of fractional PID controller (PI^alpha D^beta over conventional PID for the cart-servo laboratory set-up. The designed controllers are optimum in the sense of Integral Absolute Error (IAE and Integral Square Error (ISE. The paper contributes in three aspects: 1 Acquiring nonlinear mathematical model for the cart-servo laboratory set-up, 2 Designing fractional and integer order PID for minimizing IAE, ISE, 3 Analyzing the performance of designed controllers for simulated plant model as well as real plant. The results show a significantly superior performance by PI^alpha D^beta as compared to the conventional PID controller.

  18. Practical guidelines for setting up neurosurgery skills training cadaver laboratory in India

    Directory of Open Access Journals (Sweden)

    Ashish Suri

    2014-01-01

    Full Text Available Though the necessity of cadaver dissection is felt by the medical fraternity, and described as early as 600 BC, in India, there are no practical guidelines available in the world literature for setting up a basic cadaver dissection laboratory for neurosurgery skills training. Hands-on dissection practice on microscopic and endoscopic procedures is essential in technologically demanding modern neurosurgery training where ethical issues, cost constraints, medico-legal pitfalls, and resident duty time restrictions have resulted in lesser opportunities to learn. Collaboration of anatomy, forensic medicine, and neurosurgery is essential for development of a workflow of cadaver procurement, preservation, storage, dissection, and disposal along with setting up the guidelines for ethical and legal concerns.

  19. Setting up international biobased commodity trade chains : a guide and 5 examples in Ukraine

    OpenAIRE

    Dam, van, A.M.; Elbersen, W.; Ree; Wubben, E.F.M.

    2014-01-01

    Setting up biobased production chains, from biomass feedstock to final biobased product (energy, chemicals, materials) is a complicated process in which a whole range of decisions have to be made. Choices include what feedstocks to use, arranging logistics and most important of all the locating facilities to compact and dewater and convert the biomass into intermediates and final products. Choices depend on the local conditions and factors such as the economy-of-scale of intermediate steps an...

  20. Controlling Mechatronic Set-up Using Real-time Linux and CTC ++

    OpenAIRE

    Broenink, Johannes F.; Jovanovic, D.S.; Hilderink, G.H.; van Amerongen, J.; Jonker, B.; Regtien, P.; Stramigioli, S.

    2002-01-01

    The development of control software for mechatronic systems is presented by means of a case study: a 2 DOF mechanical rotational set-up usable as a camera-positioning device. The control software is generated using the code generation facility of 20-SIM, thus guaranteeing the generated code being the same as verified by simulation during the controller design phase. We use CTC++ (Communicating Threads for C++) as Communication Abstraction Layer to facilitate the conversion process from the bl...

  1. An Analysis of Starting Points for Setting Up a Model of a More Reliable Ship Propulsion

    OpenAIRE

    Martinović, Dragan; Tudor, Mato; Bernečić, Dean

    2011-01-01

    This paper considers the important requirement for ship propulsion necessary for its immaculate operation, since any failure can endanger the ship and render it useless. Particular attention is given to the failure of auxiliary engines that can also seriously jeopardise the safety of the ship. Therefore the paper presents preliminary investigations for setting up models of reliable ship propulsion accounting for the failure of auxiliary engines. Models of most frequent implementations of e...

  2. Setting up a fast-track insulin start clinic for type 2 diabetes.

    Science.gov (United States)

    Burden, Mary; Byard, Caroline; Gregory, Robert; Khulpateea, Anita; Burden, Andrew

    When people with established type 2 diabetes first need insulin therapy there is often a delay in accessing services. Since the report of the UK Prospective Diabetes Study was published it has been recognised that people with type 2 diabetes have a progressive disease and a need for increasing treatment. The authors set up a fast-track service to enable GPs and practice nurses to refer to a nurse-led service at the diabetes centre.

  3. [A discussion on setting up target age group for immunization against leptospirosis].

    Science.gov (United States)

    Zhuo, J T; Wang, S S; Lan, W L

    1995-08-01

    This paper presented the lesson of setting up a false immunization priority age group for leptospirosis which failed to prevent the leptospirosis outbreak. Our experience was that in the rice paddy field type endemic area the priority age group for the vaccination against leptopirosis should be 15 to 34 year olds followed by 35 years old or above. There was no preventive effect in the vaccination for the children 14 years old or yaunger, to our observation.

  4. Integration of micro milling highspeed spindle on a microEDM-milling machine set-up

    DEFF Research Database (Denmark)

    De Grave, Arnaud; Hansen, Hans Nørgaard; Andolfatto, Loic

    2009-01-01

    In order to cope with repositioning errors and to combine the fast removal rate of micro milling with the precision and small feature size achievable with micro EDM milling, a hybrid micro-milling and micro-EDM milling centre was built and tested. The aim was to build an affordable set-up, easy...... by micro milling. Examples of test parts are shown and used as an experimental validation....

  5. The importance of set up time and temperature in real-time PCR; an essential reminder.

    Science.gov (United States)

    Cassidy, Hayley; MacLean, Alasdair; Gunson, Rory

    2017-05-01

    Non-specific amplification can arise in real-time PCR when temperatures are above 4°C during PCR set up. Pressure of high throughput tests, particularly in a clinical setting, can lead to short cuts being taken during PCR set up. This study set out to evaluate the outcome of exposing a real-time PCR assay to increasing durations of room temperature prior to PCR amplification. A real-time PCR assay was exposed to increasing durations of room temperature prior to PCR amplification. We found that reactions left at room temperature for 30min or more produced non-specific traces in the negative controls which could be mistaken for weak positive traces. In addition we found that the fluorescence of positive control traces was significantly reduced indicating reduced reaction efficiency, however the Ct valves were comparable between all reactions highlighting that control Ct monitoring alone would not have detected this issue. This study acts as a reminder for PCR users to set up reactions on ice/chill blocks prior to PCR amplification. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Broadband short pulse measurement by autocorrelation with a sum-frequency generation set-up

    Energy Technology Data Exchange (ETDEWEB)

    Glotin, F.; Jaroszynski, D.; Marcouille, O. [LURE, Orsay (France)] [and others

    1995-12-31

    Previous spectral and laser pulse length measurements carried out on the CLIO FEL at wavelength {lambda}=8.5 {mu}m suggested that very short light pulses could be generated, about 500 fs wide (FWHM). For these measurements a Michelson interferometer with a Te crystal, as a non-linear detector, was used as a second order autocorrelation device. More recent measurements in similar conditions have confirmed that the laser pulses observed are indeed single: they are not followed by other pulses distant by the slippage length N{lambda}. As the single micropulse length is likely to depend on the slippage, more measurements at different wavelengths would be useful. This is not directly possible with our actual interferometer set-up, based on a phase-matched non-linear crystal. However, we can use the broadband non-linear medium provided by one of our users` experiments: Sum-Frequency Generation over surfaces. With such autocorrelation set-up, interference fringes are no more visible, but this is largely compensated by the frequency range provided. First tests at 8 {mu}m have already been performed to validate the technic, leading to results similar to those obtained with our previous Michelson set-up.

  7. LS1 Report: A brand new set-up for ASACUSA-CUSP

    CERN Document Server

    Antonella Del Rosso

    2014-01-01

    ASACUSA is running for the first time with a totally new set-up. Three new vital instruments have been designed, produced and installed during LS1 in addition to several other major modifications. The collaboration is now ready to perform the first high-precision measurement of the hyperfine structure of antihydrogen – a study that aims at comparing the inner properties of matter and antimatter.   The ASACUSA set-up. The ASACUSA-CUSP collaboration comprises about 30 scientists from various institutes in Europe and Japan. Because of the Japanese contribution, the experiment is often known by its Japanese pronunciation, the experiment’s logo is in Japanese, and the logbook uses Japanese time! This year, for the first time, the experiment is running with a completely new set-up, which now includes a new superconducting double cusp magnet, a new tracking detector and a new final antihydrogen detector. “The magnet is the heart of the ASACUSA experiment,” expl...

  8. Numerical Simulation of Wave Height and Wave Set-Up in Nearshore Regions

    Institute of Scientific and Technical Information of China (English)

    郑永红; 沈永明; 邱大洪

    2001-01-01

    Based on the time dependent mild slope equation including the effect of wave energy dissipation, an expression for the energy dissipation factor is derived in conjunction with the wave energy balance equation, and then a practical method for the simulation of wave height and wave set-up in nearshore regions is presented. The variation of the complex wave amplitude is numerically simulated by use of the parabolic mild slope equation including the effect of wave energy dissipation due to wave breaking. The components of wave radiation stress are calculated subsequently by new expressions for them according to the obtained complex wave amplitude, and then the depth-averaged equation is applied to the calculation of wave set-up due to wave breaking. Numerical results are in good agreement with experimental data,showing that the expression for the energy dissipation factor is reasonable and that the new method is effective for the simulation of wave set-up due to wave breaking in nearshore regions.

  9. Modeling liquid hydrogen cavitating flow with the full cavitation model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.B.; Qiu, L.M.; Qi, H.; Zhang, X.J.; Gan, Z.H. [Institute of Refrigeration and Cryogenic Engineering, Zhejiang University, Hangzhou 310027 (China)

    2008-12-15

    Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. This paper strives towards developing an effective computational strategy to simulate liquid hydrogen cavitation relevant to liquid rocket propulsion applications. The aims are realized by performing a steady state computational fluid dynamic (CFD) study of liquid hydrogen flow over a 2D hydrofoil and an axisymmetric ogive in Hord's reports with a so-called full cavitation model. The thermodynamic effect was demonstrated with the assumption of thermal equilibrium between the gas phase and liquid phase. Temperature-dependent fluid thermodynamic properties were specified along the saturation line from the ''Gaspak 3.2'' databank. Justifiable agreement between the computed surface pressure, temperature and experimental data of Hord was obtained. Specifically, a global sensitivity analysis is performed to examine the sensitivity of the turbulent computations to the wall grid resolution, wall treatments and changes in model parameters. A proper near-wall model and grid resolution were suggested. The full cavitation model with default model parameters provided solutions with comparable accuracy to sheet cavitation in liquid hydrogen for the two geometries. (author)

  10. Theoretical hydrodynamics

    CERN Document Server

    Milne-Thomson, L M

    2011-01-01

    This classic exposition of the mathematical theory of fluid motion is applicable to both hydrodynamics and aerodynamics. Based on vector methods and notation with their natural consequence in two dimensions - the complex variable - it offers more than 600 exercises and nearly 400 diagrams. Prerequisites include a knowledge of elementary calculus. 1968 edition.

  11. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  12. Ship Hydrodynamics

    Science.gov (United States)

    Lafrance, Pierre

    1978-01-01

    Explores in a non-mathematical treatment some of the hydrodynamical phenomena and forces that affect the operation of ships, especially at high speeds. Discusses the major components of ship resistance such as the different types of drags and ways to reduce them and how to apply those principles for the hovercraft. (GA)

  13. On the hydrodynamics of rocket propellant engine inducers and turbopumps

    Science.gov (United States)

    d'Agostino, L.

    2013-12-01

    The lecture presents an overview of some recent results of the work carried out at Alta on the hydrodynamic design and rotordynamic fluid forces of cavitating turbopumps for liquid propellant feed systems of modern rocket engines. The reduced order models recently developed for preliminary geometric definition and noncavitating performance prediction of tapered-hub axial inducers and centrifugal turbopumps are illustrated. The experimental characterization of the rotordynamic forces acting on a whirling four-bladed, tapered-hub, variable-pitch high-head inducer, under different load and cavitation conditions is presented. Future perspectives of the work to be carried out at Alta in this area of research are briefly illustrated.

  14. Numerical analysis of the effects of radiation heat transfer and ionization energy loss on the cavitation Bubble's dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Mahdi, M. [Faculty of Mechanical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Ebrahimi, R. [Faculty of Aerospace Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Shams, M., E-mail: shams@kntu.ac.ir [Faculty of Mechanical Engineering, K.N. Toosi University of Technology, Pardis St., Molla-Sadra Ave, Vanak. Sq., P.O. Box: 19395-1999, Tehran (Iran, Islamic Republic of)

    2011-06-13

    A numerical scheme for simulating the acoustic and hydrodynamic cavitation was developed. Bubble instantaneous radius was obtained using Gilmore equation which considered the compressibility of the liquid. A uniform temperature was assumed for the inside gas during the collapse. Radiation heat transfer inside the bubble and the heat conduction to the bubble was considered. The numerical code was validated with the experimental data and a good correspondence was observed. The dynamics of hydrofoil cavitation bubble were also investigated. It was concluded that the thermal radiation heat transfer rate strongly depended on the cavitation number, initial bubble radius and hydrofoil angle of attack. -- Highlights: → Heat transfer and ionization energy losses were analyzed in the cavitation bubble. → Radiation of hydrodynamic bubble was approximately equal to the black body. → Radiation heat transfer did not affect the bubble dynamic. → Conduction decreased the bubble pressure and increased the bubble temperature. → Ionization decreased the temperature and increased the pressure in the bubble.

  15. Prediction of Shock-Induced Cavitation in Water

    Science.gov (United States)

    Brundage, Aaron

    2013-06-01

    Fluid-structure interaction problems that require estimating the response of thin structures within fluids to shock loading has wide applicability. For example, these problems may include underwater explosions and the dynamic response of ships and submarines; and biological applications such as Traumatic Brain Injury (TBI) and wound ballistics. In all of these applications the process of cavitation, where small cavities with dissolved gases or vapor are formed as the local pressure drops below the vapor pressure due to shock hydrodynamics, can cause significant damage to the surrounding thin structures or membranes if these bubbles collapse, generating additional shock loading. Hence, a two-phase equation of state (EOS) with three distinct regions of compression, expansion, and tension was developed to model shock-induced cavitation. This EOS was evaluated by comparing data from pressure and temperature shock Hugoniot measurements for water up to 400 kbar, and data from ultrasonic pressure measurements in tension to -0.3 kbar, to simulated responses from CTH, an Eulerian, finite volume shock code. The new EOS model showed significant improvement over pre-existing CTH models such as the SESAME EOS for capturing cavitation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy/NNSA under contract DE-AC04-94AL85000.

  16. Radiation Hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Castor, J I

    2003-10-16

    The discipline of radiation hydrodynamics is the branch of hydrodynamics in which the moving fluid absorbs and emits electromagnetic radiation, and in so doing modifies its dynamical behavior. That is, the net gain or loss of energy by parcels of the fluid material through absorption or emission of radiation are sufficient to change the pressure of the material, and therefore change its motion; alternatively, the net momentum exchange between radiation and matter may alter the motion of the matter directly. Ignoring the radiation contributions to energy and momentum will give a wrong prediction of the hydrodynamic motion when the correct description is radiation hydrodynamics. Of course, there are circumstances when a large quantity of radiation is present, yet can be ignored without causing the model to be in error. This happens when radiation from an exterior source streams through the problem, but the latter is so transparent that the energy and momentum coupling is negligible. Everything we say about radiation hydrodynamics applies equally well to neutrinos and photons (apart from the Einstein relations, specific to bosons), but in almost every area of astrophysics neutrino hydrodynamics is ignored, simply because the systems are exceedingly transparent to neutrinos, even though the energy flux in neutrinos may be substantial. Another place where we can do ''radiation hydrodynamics'' without using any sophisticated theory is deep within stars or other bodies, where the material is so opaque to the radiation that the mean free path of photons is entirely negligible compared with the size of the system, the distance over which any fluid quantity varies, and so on. In this case we can suppose that the radiation is in equilibrium with the matter locally, and its energy, pressure and momentum can be lumped in with those of the rest of the fluid. That is, it is no more necessary to distinguish photons from atoms, nuclei and electrons, than it is

  17. Attitudes of Family Planning Workers toward Setting Up Special Counseling Stations for Unmarried Young Adults

    Institute of Scientific and Technical Information of China (English)

    涂晓雯; 刘英惠; 楼超华; 高尔生

    2001-01-01

    Objective To understand attitudes of family planning workers to setting up special counseling stations for unmarried young adults and to identify the acceptable and feasible ways to provide the services for unmarried young adults in eight provinces/cities in ChinaMethods From May 1998to December 1998, 1 927family planning workers including 965 contraceptive providers and 962 contraceptive distributors were recruited for questionnaire survey in eight provinces/cities in China.Results Except the subjects from Hebei Province, over 70% of all the subjects from other provinces/cities thought it was necessary to have a special counseling station set up for unmarried young adults, while 10~ 20% of them opposed to it. Result of Multivariable Logistic regression analysis showed that where the subjects came from, were contraceptive distributors, have higher education level, younger than 50, expressed tolerance for premarital sex, perceived that unmarried young adults had no or inadequate knowledge about sexuality and considered it was difficult for unmarried young adults to obtain contraceptive methods, were more likely to support the establishment of special counseling stations for unmarried youth. The acceptable and feasible ways to provide contraceptive services varied from one province/city to another. Generally,family planning counseling stations and hospital were the most acceptable place to provide counseling services for unmarried young adults in eight provinces/cities. Specially trained persons were recommended as the suitable persons for providing the services for unmarried young adults. Conclusion It is acceptable and feasible to set up special counseling stations for unmarried young adults.

  18. Set-up and characterization of a humidity sensor realized in LTCC-technology

    CERN Document Server

    Smetana, W

    2008-01-01

    A new type of integrated temperature and humidity sensor applying LTCC-technology has been developed and characterized. In this approach, sensing elements are implemented using heated metal resistors (Pt-elements), where one is exposed to the humid environment that causes the sensor element to cool down with increased humidity, while the other one is sealed from the environment. Sensor design is based on FEA (Finite Element Analyses) where the critical design parameters have been analyzed with regard to the performance characteristic of the device. The set-up of sensor element will be shown and the functional capability will be demonstrated by experimental results.

  19. ECONOMIC EVALUATION OF A BREEDING PROGRAMME FOR SETTING UP TWO HIGH PERFORMANCES BEE LINES

    Directory of Open Access Journals (Sweden)

    A POPESCU

    2003-10-01

    Full Text Available This study aimed to evaluate costs, incomes and financial results related to the creation of two Apis Mellifica Carpatica lines, based on a specific Breeding Programme within a closed population. The two beelines have been carefully selected for the bee populations living in two areas of Romania: North Moldavia and South Muntenia. A new selection technology is set up in order to produce high performance queen bees, well adapted to the environmental conditions mainly to picking. Genetic gain will be get by selling the mated selected queens belonging to the two lines to various beekeepers interested to obtain more and high quality bee products.

  20. Setting up robotic surgery in gynaecology: the experience of the Strasbourg teaching hospital.

    Science.gov (United States)

    Sananès, N; Garbin, O; Hummel, M; Youssef, C; Vizitiu, R; Lemaho, D; Rottenberg, D; Diemunsch, P; Wattiez, A

    2011-06-01

    Teleoperated surgical robots could provide a genuine breakthrough in laparoscopy and it is for this reason that the development of robot-assisted laparoscopy is one of the priorities of the Strasbourg University Hospitals' strategic plan. The hospitals purchased a da Vinci S(®) robot in June 2006 and Strasbourg has, in IRCAD, one of the few robotic surgery training centres in the world. Our experience has, however, revealed the difficulties involved in setting up robotic surgery, the first of which are organizational issues. This prospective work was carried out between December 2007 and September 2008, primarily to examine the possibility of setting up robotic surgery on a regular basis for gynaecological surgical procedures at the Strasbourg University Hospitals. We maintained a "logbook" in which we prospectively noted all the resources implemented in setting up the robotic surgery service. The project was divided into two phases: the preparatory phase up until the first hysterectomy and then the second phase with the organization of subsequent hysterectomies. The first surgical procedure took 5 months to organize, and followed 25 interviews, 10 meetings, 53 telephone conversations and 48 e-mails with a total of 40 correspondents. The project was presented to seven separate groups, including the hospital medical commission, the gynaecology unit committee and the surgical staff. Fifteen members of the medical and paramedical team attended a two-day training course. Preparing the gynaecology department for robotic surgery required freeing up 8.5 days of "physician time" and 12.5 days of "nurse time". In the following five months, we performed five hysterectomies. Preparation for each procedure involved on average 5 interviews, 19 telephone conversations and 11 e-mails. The biggest obstacle was obtaining an operating slot, as on average it required 18 days, four telephone calls and four e-mails to be assigned a slot in the operating theatre schedule, which is

  1. Application of activation methods on the Dubna experimental transmutation set-ups.

    Science.gov (United States)

    Stoulos, S; Fragopoulou, M; Adloff, J C; Debeauvais, M; Brandt, R; Westmeier, W; Krivopustov, M; Sosnin, A; Papastefanou, C; Zamani, M; Manolopoulou, M

    2003-02-01

    High spallation neutron fluxes were produced by irradiating massive heavy targets with proton beams in the GeV range. The experiments were performed at the Dubna High Energy Laboratory using the nuclotron accelerator. Two different experimental set-ups were used to produce neutron spectra convenient for transmutation of radioactive waste by (n,x) reactions. By a theoretical analysis neutron spectra can be reproduced from activation measurements. Thermal-epithermal and fast-super-fast neutron fluxes were estimated using the 197Au, 238U (n,gamma) and (n,2n) reactions, respectively. Depleted uranium transmutation rates were also studied in both experiments.

  2. [Approaches to setting up the Center for identification of exhumed bodies in Chechen Republic].

    Science.gov (United States)

    Klevno, V A; Ivanov, P L

    2007-01-01

    The authors participated in the activity of a group of European experts who visited Moscow, Rostov-on-Don and Grozny in September 2005 to clarify situation with identification of exhumed unknown dead bodies of the civil population. The European experts recommend to set up Center for Identification in Chechen Republic (in Grozny). The authors propose to make DNA identification tests in the Russian Federation Center for Forensic Medical Evaluation in Moscow which has much experience and staff skilled in identification of unknown exhumed bodies and can solve the problem of genetic identification of unidentified bodies of people missed in the Chechen Republic more effectively.

  3. The regional commission for medical accidents and nosocomial infections set up by French law.

    Science.gov (United States)

    Bartoli, C; Piercecchi-Marti, M D; Pelissier-Alicot, A L; Cianfarani, F; Leonetti, G

    2005-07-01

    The regional commission for conciliation and compensation for medical accidents, iatrogenic diseases and nosocomial infections (commission régionale de conciliation et d'indemnisation des accidents médicaux, affections iatrogènes et infections nosocomiales, CRCI) offers victims of such events the possibility of obtaining compensation without recourse to legal proceedings. We suggest various points of view about this commission set up by the French law no. 2002-303 of 4 March 2002: the composition, role and competence of the CRCI; the place of the expert's report; the opinion pronounced by the CRCI and its outcome, the compensation of victims and, finally, interaction with other procedures.

  4. Setting up Information Literacy Workshops in School Libraries: Imperatives, Principles and Methods

    Directory of Open Access Journals (Sweden)

    Reza Mokhtarpour

    2010-09-01

    Full Text Available While many professional literature have talked at length about the importance of dealing with information literacy in school libraries in ICT dominated era, but few have dealt with the nature and mode of implementation nor offered a road map. The strategy emphasized in this paper is to hold information literacy sessions through effective workshops. While explaining the reasons behind such workshops being essential in enhancing information literacy skills, the most important principles and stages for setting up of such workshops are offered in a step-by-step manner.

  5. Sino-British Researchers Join Forces to Set Up an Alpine Botanic Garden in Southwest China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ The nameplate for the Lijiang Alpine Botanic Garden was unveiled on January 25 in southwest China's Yunnan Province.As a Sino-British cooperation project for a biodiversity research and protection and plant conservation platform in southwest China, the garden was jointly set up by the Royal Botanic Garden Edinburgh (RBGE)and the CAS Kunming Institute of Botany (KIB). The event also marked the start of a one-year UK-China Partners in Science campaign in southwest China. British ConsulGeneral in Chongqing Tim Summers,RBGE Regius Keeper Stephen Blackmore and KIB vice directors Li Dezhu and Yang Yongping were in Lijiang to witnessthe ceremony.

  6. Setting up LAMP getting Linux, Apache, MySQL, and PHP working together

    CERN Document Server

    Rosebrock, Eric

    2006-01-01

    You could think of Setting Up LAMP as four books in one, but it''s actually something much more valuable: a single volume that presents the open-source technologies known collectively as LAMP-Linux, Apache, MySQL, and PHP-as tightly dovetailed components of today''s most affordable and effective platform for building dynamic web-based applications. Each technology has uses outside of this context, of course, but within it they form something greater than the sum of their parts. This book shows you how to take full advantage of this power, walking you through all the steps required to lay your

  7. Influence of the working electrode area on the cavitation-corrosion behaviour of a duplex stainless steel in aqueous LiBr solution

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Garcia, D.M.; Blasco-Tamarit, E.; Igual-Munoz, A.; Garcia-Anton, J. [Valencia Univ. Politecnica, Dept. de Ingenieria Quimica y Nuclear. ETSI Industriales, Valencia (Spain)

    2009-07-01

    Cavitation erosion can occur in almost all hydrodynamic systems and turbo machines, e.g. pumps, valves, marine propeller and hydraulic turbines. It causes serious material damage. Corrosion problems associated with cavitation can appear on different points in LiBr absorption machines. Many efforts have been made to solve this problem, such as optimizing the design of the flow-handling component and selecting better materials and coatings to resist the cavitation erosion-corrosion. A better understanding of cavitation erosion-corrosion mechanisms is very important for the selection materials and coatings. The objective of the present work was to study the influence of the exposed area of the working electrode on the corrosion behaviour of a duplex stainless steel (EN 1.4462) in a 992 g/l LiBr solution under static conditions (without cavitation) and dynamic conditions (with cavitation) at 25 C. Potentiodynamic cyclic curves were obtained under static and dynamic conditions exposing different areas of the working electrode: 1.6 mm diameter (0.02 cm{sup 2} area ), 4 mm diameter (0.12 cm{sup 2} area), 6 mm diameter (0.28 cm{sup 2} area) and 8 mm diameter (0.5 cm{sup 2} area). The dynamic conditions were generated using an ultrasonic cavitation facility in a three-electrode electrochemical cell. The Potentiodynamic Cyclic curves obtained with and without cavitation have been compared and different tendencies were observed. Cavitation increased the cathodic current density when the exposed area to the solution is large (6 mm and 8 mm diameters). This behaviour was not observed during the tests with smaller electrode areas (1.6 mm and 4 mm diameters). In all cases, cavitation increased the anodic current densities independently of the exposed area to the solution. Besides, cavitation favoured the pitting corrosion, since lower pitting potentials were obtained under cavitation conditions than under static conditions. (authors)

  8. Numerical investigation of cavitation flow inside spool valve with large pressure drop

    Science.gov (United States)

    Deng, Jian; Pan, Dingyi; Xie, Fangfang; Shao, Xueming

    2015-12-01

    Spool valves play an important role in fluid power system. Cavitation phenomena happen frequently inside the spool valves, which cause structure damages, noise and lower down hydrodynamic performance. A numerical tools incorporating the cavitation model, are developed to predict the flow structure and cavitation pattern in the spool valve. Two major flow states in the spool valve chamber, i.e. flow-in and flow-out, are studies. The pressure distributions along the spool wall are first investigated, and the results agree well with the experimental data. For the flow-in cases, the local pressure at the throttling area drops much deeper than the pressure in flow-out cases. Meanwhile, the bubbles are more stable in flow-in cases than those in flow-out cases, which are ruptured and shed into the downstream.

  9. Bacterial hydrodynamics

    CERN Document Server

    Lauga, Eric

    2015-01-01

    Bacteria predate plants and animals by billions of years. Today, they are the world's smallest cells yet they represent the bulk of the world's biomass, and the main reservoir of nutrients for higher organisms. Most bacteria can move on their own, and the majority of motile bacteria are able to swim in viscous fluids using slender helical appendages called flagella. Low-Reynolds-number hydrodynamics is at the heart of the ability of flagella to generate propulsion at the micron scale. In fact, fluid dynamic forces impact many aspects of bacteriology, ranging from the ability of cells to reorient and search their surroundings to their interactions within mechanically and chemically-complex environments. Using hydrodynamics as an organizing framework, we review the biomechanics of bacterial motility and look ahead to future challenges.

  10. Nanoflow hydrodynamics

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; Dyre, Jeppe C.; Daivis, Peter J.;

    2011-01-01

    We show by nonequilibrium molecular dynamics simulations that the Navier-Stokes equation does not correctly describe water flow in a nanoscale geometry. It is argued that this failure reflects the fact that the coupling between the intrinsic rotational and translational degrees of freedom becomes...... important for nanoflows. The coupling is correctly accounted for by the extended Navier-Stokes equations that include the intrinsic angular momentum as an independent hydrodynamic degree of freedom. © 2011 American Physical Society....

  11. A digital holography set-up for 3D vortex flow dynamics

    Science.gov (United States)

    Lebon, Benoît; Perret, Gaële; Coëtmellec, Sébastien; Godard, Gilles; Gréhan, Gérard; Lebrun, Denis; Brossard, Jérôme

    2016-06-01

    In the present paper, a digital in-line holography (DIH) set-up, with a converging beam, is used to take three-dimensional (3D) velocity measurements of vortices. The vortices are formed periodically at the edges of a submerged horizontal plate submitted to regular waves. They take the form of vortex filaments that extend from side to side of the channel. They undergo strongly three-dimensional instability mechanisms that remain very complicated to characterize experimentally. The experiments are performed in a 10 × 0.3 × 0.3 m3 wave flume. The DIH set-up is performed using a modulated laser diode emitting at the wavelength of 640 nm and a lensless CCD camera. The beam crosses the channel side to side. To reveal the flow dynamics, 30-μm hydrogen bubbles are generated at the edge of the plate to serve as tracers. Their locations are recorded on the holograms multiple times to access the dynamics of the flow. This method leads to an accuracy in the order of 100 μm on the axial location. Those measurements have been validated with stereo-PIV measurements. A very good agreement is found on time-averaged velocity fields between the two techniques.

  12. Quality assurance set-up for a new positron emission tomography detector

    Energy Technology Data Exchange (ETDEWEB)

    Cortinovis, Daniele; Xu, Chen; Zvolsky, Milan [DESY, Hamburg (Germany); Hamburg Univ. (Germany); Garutti, Erika [Hamburg Univ. (Germany); Silenzi, Alessandro [DESY, Hamburg (Germany)

    2013-07-01

    The PicoSEC-MCNet Project (PICOsecond Siliconphotomultiplier-Electronics- and Crystal research-Marie-Curie-Network) aims to develop a new class of ultra-fast photon detectors for High Energy Physics (HEP) and Positron Emission Tomography (PET). This actual technology development is covered in the EndoTOFPET-US project. A new Time Of Flight PET detector will improve the diagnosis capability of pancreatic and prostate tumors with unprecedented spatial resolution. The detector consists of two parts: a PET head mounted on an ultrasound probe and an external plate. Photons are detected by scintillating crystals individually readout by silicon photomultipliers (SiPMs). Their fast response allows to meet the critical requirement of at least 200 ps (FWHM) coincidence time resolution, essential for a spatial resolution of 3 cm along the Line Of Response (LOR) and efficient background rejection. DESY together with Hamburg University are responsible for the quality assurance and the commissioning of the whole system, and the necessary infrastructure is being set up. Within this task, the light yield uniformity for the combined scintillator-SiPM system of the external plate must be measured. This talk will introduce and describe the set-up which will allows a fast, automatic and high precision measurement of the light yield for the 4096 combined scintillator-SiPMs of the external plate.

  13. Setting up of a cerebral visual impairment clinic for children: Challenges and future developments.

    Science.gov (United States)

    Philip, Swetha Sara

    2017-01-01

    The aim of this study is to describe the setting up of a cerebral visual impairment (CVI) clinic in a tertiary care hospital in South India and to describe the spectrum of cases seen. The CVI clinic, set up in February 2011, receives interdisciplinary input from a core team involving a pediatrician, neurologist, psychiatrist, occupational therapist, pediatric ophthalmologist, and an optometrist. All children, cerebral palsy (CP), learning disability, autism, neurodegenerative diseases, and brain trauma are referred to the clinic for functional vision assessment and opinion for further management. One thousand four hundred and seventy-eight patients were seen in the CVI clinic from February 2011 to September 2015. Eighty-five percent of the patients were from different parts of India. In the clinic, 61% had CP, 28% had seizure disorders, autism was seen in 9.5%, and learning disability, neurodegenerative conditions, and brain injury together constituted 1.5%. Most of the children (45%) had moderate CP. Forty percent of CVI was due to birth asphyxia, but about 20% did not have any known cause for CVI. Seventy percent of patients, who came back for follow-up, were carrying out the habilitation strategies suggested. Average attendance of over 300 new patients a year suggests a definite need for CVI clinics in the country. These children need specialized care to handle their complex needs. Although difficult to coordinate, an interdisciplinary team including the support groups and voluntary organizations is needed to facilitate the successful implementation of such specialized service.

  14. Setting up of teeth in the neutral zone and its effect on speech.

    Science.gov (United States)

    Al-Magaleh, Wafa'a Radwan; Swelem, Amal Ali; Shohdi, Sahar Saad; Mawsouf, Nadia Mohamed

    2012-01-01

    Rational goals for denture construction are basically directed at the restoration of esthetics and masticatory function and the healthy preservation of the remaining natural tissues. Little concern has been given to the perfection and optimization of the phonetic quality of denture users. However, insertion of prosthodontic restorations may lead to speech defects. Most such defects are mild but, nevertheless, can be a source of concern to the patient. For the dental practitioner, there are few guidelines for designing a prosthetic restoration with maximum phonetic success. One of these guidelines involves the setting up of teeth within the neutral zone. The aim of this study was to evaluate, subjectively and objectively, the effect on speech of setting up teeth in the neutral zone. Three groups were examined: group I (control) included 10 completely dentulous subjects, group II included 10 completely edentulous patients with conventional dentures, and group III included the same 10 edentulous patients with neutral zone dentures. Subjective assessment included patient satisfaction. Objective assessment included duration taken for recitation of Al-Fateha and acoustic analysis. Subjectively, patients were more satisfied with their neutral zone dentures. Objectively, speech produced with the neutral zone dentures was closer to normal than speech with conventional dentures.

  15. Set Up of an Automatic Water Quality Sampling System in Irrigation Agriculture

    Directory of Open Access Journals (Sweden)

    Emanuel Heinz

    2013-12-01

    Full Text Available We have developed a high-resolution automatic sampling system for continuous in situ measurements of stable water isotopic composition and nitrogen solutes along with hydrological information. The system facilitates concurrent monitoring of a large number of water and nutrient fluxes (ground, surface, irrigation and rain water in irrigated agriculture. For this purpose we couple an automatic sampling system with a Wavelength-Scanned Cavity Ring Down Spectrometry System (WS-CRDS for stable water isotope analysis (δ2H and δ18O, a reagentless hyperspectral UV photometer (ProPS for monitoring nitrate content and various water level sensors for hydrometric information. The automatic sampling system consists of different sampling stations equipped with pumps, a switch cabinet for valve and pump control and a computer operating the system. The complete system is operated via internet-based control software, allowing supervision from nearly anywhere. The system is currently set up at the International Rice Research Institute (Los Baños, The Philippines in a diversified rice growing system to continuously monitor water and nutrient fluxes. Here we present the system’s technical set-up and provide initial proof-of-concept with results for the isotopic composition of different water sources and nitrate values from the 2012 dry season.

  16. Monitoring electro-magnetic field in urban areas: new set-ups and results

    Energy Technology Data Exchange (ETDEWEB)

    Lubritto, C.; Petraglia, A.; Paribello, G.; Formosi, R.; Rosa, M. de; Vetromile, C.; Palmieri, A.; D' Onofrio, A. [Seconda Universita di Napoli, Dipt. di Scienze Ambientali, Caserta (Italy); Di Bella, G.; Giannini, V. [Vector Group, Roma (Italy)

    2006-07-01

    In this paper two different set-ups for continuous monitoring of electromagnetic levels are presented: the first one (Continuous Time E.M.F. Monitoring System) is based upon a network of fixed stations, allowing a detailed field monitoring as function of the time; the second one (Mobile Measurements Units) resorts to portable stations mounted on standard bicycles, allowing a positional screening in limited time intervals. For both set-ups a particular attention has been paid to the data management, by means of tools like web geographic information systems (Web-Gis). Moreover the V.I.C.R.E.M./E.L.F. software has been used for a predictive analysis of the electromagnetic field levels along with the geo referenced data coming from the field measurements. Starting from these results it has been realized that there is a need for an efficient and correct action of monitoring and information/formation in this domain, where dis-information or bad information is very often spread in the population, in particular in a field where the process of the appreciation and assessment of risk does not necessarily make use of a rationale, technically-informed procedure, but the judgement is rather based on a personal feeling, which may derive from a limited, unstructured set of information, using a set of qualitative attributes rather than a quantity. (N.C.)

  17. Probing neutrino parameters with a Two-Baseline Beta-beam set-up

    CERN Document Server

    Agarwalla, S K; Raychaudhuri, A

    2008-01-01

    We discuss the prospects of exploring the neutrino mass parameters with a CERN based Beta-beam experiment using two different detectors at two different baselines. The proposed set-up consists of a 50 kton iron calorimeter (ICAL) at a baseline of around 7150 km which is roughly the magic baseline, e.g., ICAL@INO, and a 50 kton Totally Active Scintillator Detector at a distance of 730 km, e.g., at Gran Sasso. We take 8B and 8Li source ions with a boost factor $\\gamma$ of 650 for the magic baseline while for the closer detector we consider 18Ne and 6He ions with a range of Lorentz boosts. We find that the locations of the two detectors complement each other leading to an exceptional high sensitivity. With $\\gamma=650$ for 8B/8Li and $\\gamma=575$ for 18Ne/6He and total luminosity corresponding to $5\\times (1.1\\times 10^{19})$ and $5\\times (2.9\\times 10^{19})$ useful ion decays in neutrino and antineutrino modes respectively, we find that the two-detector set-up can probe maximal CP violation and establish the ne...

  18. A new mechatronic set-up and technique for investigation of firearms

    Science.gov (United States)

    Lesenciuc, Ioan; Suciu, Cornel

    2016-12-01

    Since ancient times, mankind has manifested interest in the development and improvement of weapons, either for military or hunting purposes. Today, in competition with these legal practices, the number of those who commit crimes by non-compliance with the regime of weapons and ammunition has increased exponentially. This is why the technology and methods employed in the area of judicial ballistics, requires constant research and continuous learning. The present paper advances a new experimental set-up and its corresponding methodology, meant to measure the force deployed by the firing pin. The new experimental set-up and procedure consists of a mechatronic structure, based on a piezoelectric force transducer, which allows to measure, in-situ, the force produced by the firing pin when it is deployed. The obtained information can further be used to establish a correspondence between this force and the imprint left on the firing cap. This correspondence furthers the possibility of elaborating a model that would permit ballistic experts to correctly identify a smoothbore weapon.

  19. The learning unit "Orthodontic set-up" as a new-media module in teaching.

    Science.gov (United States)

    Asselmeyer, T; Fischer, V; Matthies, H; Schwestka-Polly, R

    2004-07-01

    The present study examines the extent to which computer-assisted learning units provided independently of place and time are used in self-study as a supplement to the classical classroom instruction of dental students. Indications as to whether such teaching modules improve training in orthodontics should be obtained from this. Attention was focussed on the implementation and evaluation of the "Orthodontic set-up" teaching module, which can be accessed in the Internet and Intranet of the university. The didactic arrangement offered classical university courses in parallel (four lectures on the subjects of occlusion, function, diagnostics, and therapy) in addition to the electronically communicated teaching contents. In addition, intensive supervision during the production of the set-up was guaranteed. The use of this multimedia learning concept was in general assessed positively by 63 surveyed students in the 2002/03 winter semester. The results revealed on the one hand the intensity of use and features of the acquisition of knowledge (use types), and on the other hand, in terms of professional relevance, the contents were found to be well explained, didactically attractive, and understandably presented. However, numerous drawbacks were also mentioned (technical and time problems; qualification deficits). The experience gained in this project should encourage more future investment in the development of alternative university didactic models.

  20. Optical digital to analog conversion performance analysis for indoor set-up conditions

    Science.gov (United States)

    Dobesch, Aleš; Alves, Luis Nero; Wilfert, Otakar; Ribeiro, Carlos Gaspar

    2017-10-01

    In visible light communication (VLC) the optical digital to analog conversion (ODAC) approach was proposed as a suitable driving technique able to overcome light-emitting diode's (LED) non-linear characteristic. This concept is analogous to an electrical digital-to-analog converter (EDAC). In other words, digital bits are binary weighted to represent an analog signal. The method supports elementary on-off based modulations able to exploit the essence of LED's non-linear characteristic allowing simultaneous lighting and communication. In the ODAC concept the reconstruction error does not simply rely upon the converter bit depth as in case of EDAC. It rather depends on communication system set-up and geometrical relation between emitter and receiver as well. The paper describes simulation results presenting the ODAC's error performance taking into account: the optical channel, the LED's half power angle (HPA) and the receiver field of view (FOV). The set-up under consideration examines indoor conditions for a square room with 4 m length and 3 m height, operating with one dominant wavelength (blue) and having walls with a reflection coefficient of 0.8. The achieved results reveal that reconstruction error increases for higher data rates as a result of interference due to multipath propagation.

  1. The effect of different foot and hand set-up positions on backstroke start performance.

    Science.gov (United States)

    de Jesus, Karla; de Jesus, Kelly; Abraldes, J Arturo; Mourão, Luis; Borgonovo-Santos, Márcio; Medeiros, Alexandre I A; Gonçalves, Pedro; Chainok, Phornpot; Fernandes, Ricardo J; Vaz, Mário A P; Vilas-Boas, João Paulo

    2016-11-01

    Foot and hand set-up position effects were analysed on backstroke start performance. Ten swimmers randomly completed 27 starts grouped in trials (n = 3) of each variation, changing foot (totally immersed, partially and totally emerged) and hand (lowest, highest horizontal and vertical) positioning. Fifteen cameras recorded kinematics, and four force plates collected hands and feet kinetics. Standardised mean difference and 95% confidence intervals were used. Variations with feet immersed have shown lower vertical centre of mass (CM) set-up position (0.16 m), vertical impulse exerted at the hands, horizontal and vertical impulse exerted at the feet (0.28, 0.41, 0.16 N/BW.s, respectively) than feet emerged with hands horizontal and vertically positioned. Most variations with feet partially emerged exhibited higher and lesser vertical impulse exerted at hands than feet immersed and emerged (e.g. vertical handgrip, 0.13, 0.15 N/BW.s, respectively). Variation with feet emerged and hands on the lowest horizontal handgrip depicted shorter horizontal (0.23, 0.26 m) and vertical CM positioning at flight (0.16, 0.15 m) than the highest horizontal and vertical handgrip, respectively. Start variations have not affected 15-m time. Variations with feet partially or totally emerged depicted advantages, but focusing on the entry and underwater biomechanics is relevant for a shorter start time.

  2. Numerical Study of Unsteady Cavitating Flows around a Hydrofoil

    Directory of Open Access Journals (Sweden)

    Ahmed Bel Hadj Taher

    2017-01-01

    Full Text Available In this paper, we report the results of a numerical investigation on unsteady cavitating flows around a circular leading edge (CLE hydrofoil. The objective of this study is to properly predict the appearance of cavitation pocket, its development and its detachment causing adverse effects on industrial systems such as microscopic plastic deformations at the solid walls. For this reason it is very important to study the influence of turbulence models on simulation results. We present a closing of the hydrodynamic equation system by a transport equation of an active scalar (volume fraction of the vapor phase with a source terms. The Computational Fluid Dynamics (CFD code used is ANSYS CFX. Before comparing the capability of the different turbulent models to predict unsteady behavior of cavitating flow along the hydrofoil, the study of the influence of the mesh resolution was performed in cavitating condition. This investigation was performed, on CLE hydrofoil, by monitoring the influence of for progressively finer meshes on the values of the drag CD and lift CL coefficients. Moreover, a study of the influence of the normal dimensionless distance to the wall (y+ was carried out on the hydrofoil surface. For the unsteady flow, a comparison of different turbulence models with the experiment leads to study the interaction of these models with the vapor pocket (detachment and collapse of vapor pocket. Two turbulence models were tested in this study: modified k-ε model and large eddy simulation (LES. In the present work, the predictions of velocity and pressure evolutions in the vicinity of the hydrofoil are compared to experimental data.

  3. Setting up a hydrological model based on global data for the Ayeyarwady basin in Myanmar

    Science.gov (United States)

    ten Velden, Corine; Sloff, Kees; Nauta, Tjitte

    2017-04-01

    The use of global datasets in local hydrological modelling can be of great value. It opens up the possibility to include data for areas where local data is not or only sparsely available. In hydrological modelling the existence of both static physical data such as elevation and land use, and dynamic meteorological data such as precipitation and temperature, is essential for setting up a hydrological model, but often such data is difficult to obtain at the local level. For the Ayeyarwady catchment in Myanmar a distributed hydrological model (Wflow: https://github.com/openstreams/wflow) was set up with only global datasets, as part of a water resources study. Myanmar is an emerging economy, which has only recently become more receptive to foreign influences. It has a very limited hydrometeorological measurement network, with large spatial and temporal gaps, and data that are of uncertain quality and difficult to obtain. The hydrological model was thus set up based on resampled versions of the SRTM digital elevation model, the GlobCover land cover dataset and the HWSD soil dataset. Three global meteorological datasets were assessed and compared for use in the hydrological model: TRMM, WFDEI and MSWEP. The meteorological datasets were assessed based on their conformity with several precipitation station measurements, and the overall model performance was assessed by calculating the NSE and RVE based on discharge measurements of several gauging stations. The model was run for the period 1979-2012 on a daily time step, and the results show an acceptable applicability of the used global datasets in the hydrological model. The WFDEI forcing dataset gave the best results, with a NSE of 0.55 at the outlet of the model and a RVE of 8.5%, calculated over the calibration period 2006-2012. As a general trend the modelled discharge at the upstream stations tends to be underestimated, and at the downstream stations slightly overestimated. The quality of the discharge measurements

  4. PROPERTIES OF NATURAL CAVITATION FLOWS AROUND A 2-D WEDGE IN SHALLOW WATER

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin; LU Chuan-jing; LI Jie; CHEN Ying

    2011-01-01

    When a body navigates with cavity in shallow water,both flexible free surface and rigid bottom wall will produce great influences on the cavity shape and hydrodynamic performances,and further affect the motion attitude and stability of the body.In the present work,characteristics of the natural cavitating flow around a 2-D symmetrical wedge in shallow water were investigated and the influences of two type boundaries on the flow pattern were analyzed.The Volume Of Fluid (VOF) multiphaseflow method which is suitable for free surface problems was utilized,coupled with a natural cavitation model to deal with the mass-transfer process between liquid and vapor phases.Within the range of the cavitation number for computation (0.07-1.81),the cavity configurations would be divided into three types,viz.,stable type,transition type and wake-vortex type.In this article,the shapes of the free surface and the cavity surface,and the hydrodynamic performance of the wedge were discussed under the conditions of relatively small cavitation number ( < 0.256 ).The present numerical cavity lengths generally accord with experimental data.When the cavitation number was decreased,the cavity was found to become longer and thicker,and the scope of the deformation of the free surface also gradually extends.The free surface and the upper cavity surface correspond fairly to their shapes.However,the lower side of the cavity surface was rather leveled due to the influence of wall boundary.The lift and drag coefficients of this 2-D wedge basically keep linear relations with the natural cavitation number smaller than 0.157,whereas direct proportion for drag and inverse proportion for lift.

  5. Cavitation Effects in Centrifugal Pumps- A Review

    Directory of Open Access Journals (Sweden)

    Maxime Binama

    2016-05-01

    Full Text Available Cavitation is one of the most challenging fluid flow abnormalities leading to detrimental effects on both the centrifugal pump flow behaviors and physical characteristics. Centrifugal pumps’ most low pressure zones are the first cavitation victims, where cavitation manifests itself in form of pitting on the pump internal solid walls, accompanied by noise and vibration, all leading to the pump hydraulic performance degradation. In the present article, a general description of centrifugal pump performance and related parameters is presented. Based on the literature survey, some light were shed on fundamental cavitation features; where different aspects relating to cavitation in centrifugal pumps were briefly discussed

  6. Calculation errors of Set-up in patients with tumor location of prostate. Exploratory study; Calculo de errores de Set-up en pacientes con localizacion tumoral de prostata. Estudio exploratorio

    Energy Technology Data Exchange (ETDEWEB)

    Donis Gil, S.; Robayna Duque, B. E.; Jimenez Sosa, A.; Hernandez Armas, O.; Gonzalez Martin, A. E.; Hernandez Armas, J.

    2013-07-01

    The calculation of SM is done from errors in positioning (set-up). These errors are calculated from movements in 3D of the patient. This paper is an exploratory study of 20 patients with tumor location of prostate in which errors of set-up for two protocols of work are evaluated. (Author)

  7. Pump Cavitation Noise Estimation from Acceleration Signals

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Do Hwan; Ha, Che Woong [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The cavitation noise can be measured directly by using pressure sensing devices. However, penetration of pipes or pump casings is inevitable to install the devices. This increases the risk of leaks. In an effort to reduce that risk, a cavitation noise estimation model based on vibration signals has been proposed. In the present study, the applicability of cavitation noise estimation methods including the previously proposed model is investigated. In order to assess the severity of cavitation, the cavitation noise estimation is necessary. In the present study, the cavitation noise is estimated by using acceleration signals measured outside of pumps and the theory of the statistical energy analysis. The applicability and limit of the cavitation noise estimation from the acceleration signals are examined by comparing the cavitation noise obtained from the pressure signal. The results suggest that the acoustic cavitation inception can be detected by the cavitation noise estimation from acceleration signals. The accuracy of the cavitation noise estimates is highly dependent on the locations of the pump casing that accelerometers attached on and the cut-off frequency of high pass filtering.

  8. Cavitation pulse extraction and centrifugal pump analysis

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Hong Lind Shaoran [University of Electronic Science and Technology of China, Chengdu (China); Yu, Bo; Qing, Biao [Xihua University, Chengdu (China)

    2017-03-15

    This study extracted cavitation pulses from hydrophone signals sampled in a centrifugal pump and analyzed their characteristics. The modified and simplified Empirical mode decomposition (EMD) algorithm was proposed for extracting cavitation pulses from strong background noise. Experimental results showed that EMD can effectively suppress noise and obtain clear cavitation pulses, facilitating the identification of the number of pulses associated with the degree of cavitation. The cavitation characteristics were modeled to predict the value of incipient cavitation. Then, we proposed a method for detecting the wear of the impeller surface. That is, the information on the impeller surface of the centrifugal pump, including the roughness of the impeller surface and its wear trends, were quantified based on the net positive suction head available of incipient cavitation. The findings indicate that the proposed technique is suitable for condition monitoring of the pump.

  9. A managed clinical network for cardiac services: set-up, operation and impact on patient care

    Directory of Open Access Journals (Sweden)

    Karen E. Hamilton

    2005-09-01

    Full Text Available Purpose: To investigate the set up and operation of a Managed Clinical Network for cardiac services and assess its impact on patient care. Methods: This single case study used process evaluation with observational before and after comparison of indicators of quality of care and costs. The study was conducted in Dumfries and Galloway, Scotland and used a three-level framework. Process evaluation of the network set-up and operation through a documentary review of minutes; guidelines and protocols; transcripts of fourteen semi-structured interviews with health service personnel including senior managers, general practitioners, nurses, cardiologists and members of the public. Outcome evaluation of the impact of the network through interrupted time series analysis of clinical data of 202 patients aged less than 76 years admitted to hospital with a confirmed myocardial infarction one-year pre and one-year post, the establishment of the network. The main outcome measures were differences between indicators of quality of care targeted by network protocols. Economic evaluation of the transaction costs of the set-up and operation of the network and the resource costs of the clinical care of the 202 myocardial infarction patients from the time of hospital admission to 6 months post discharge through interrupted time series analysis. The outcome measure was different in National Health Service resource use. Results: Despite early difficulties, the network was successful in bringing together clinicians, patients and managers to redesign services, exhibiting most features of good network management. The role of the energetic lead clinician was crucial, but the network took time to develop and ‘bed down’. Its primary “modus operand” was the development of a myocardial infarction pathway and associated protocols. Of sixteen clinical care indicators, two improved significantly following the launch of the network and nine showed improvements, which were

  10. PENERAPAN METODE TUTOR SEBAYA UNTUK MENINGKATKAN KETERAMPILANPREPARE DANTABLE SET UP DALAM MATA KULIAH TATA HIDANG

    Directory of Open Access Journals (Sweden)

    Wahyuningsih Wahyuningsih

    2011-02-01

    Full Text Available This learning teching research was intended to improve the learning outcomes of the students practicing in the subject of prepare and table set up, the main subject of Tata Hidang I (Servicing Arragements I. The subject for this research consisted of 18 S1 students of the learning group number 02 for the study Program for PKK, concentrating on Tata Boga, Departement of Service & Production Technology, the Technical Faculty of Semarang State University for the academic period of 2009-2010. This research was conducted in the gasal semester of the academic year of 2009-2010. The needed data were collected by means of tests and obsevation on the learning outcomes of the students practicing in the sub-subject of Prepare and Table Set up. The data collection used grading sheets for practices in Tata Hidang as its instrument. The data were then analized using the method of descriptive presentation. This was a classroom-action research planned in three cycles. The second and third cycles were implemented based on reflections on the first cycle and on improvements that should be reached. Every cycle consisted of two face to face encounters and of 4 activities: (1planning, (2 implementations, (3 observations, (4 reflections. The results of this research showed that the use of peeer tutorials for the learning-teching pocesses had positive effects both on the students and the lecturers that it might improve the quality of lecturing for the Tata Hidang I. The grades obtained by the students from practicing in the sub-subject of prepare and table set up increased from the lowest grade C (46.7% BC and B (60% and AB (26.6 %, and AB (26.6%.. Trough the three cycles, the number of BC grade decreased from 66% to only 20%. Based on the results of this research, it is recommended that peer tutorial for the subject of Tata Hidang I and Servicing in Food & Beverage should be continued in order that the educational serveices provided to the practicing students might be

  11. Exceptional sensitivity to neutrino parameters with a two-baseline Beta-beam set-up

    Energy Technology Data Exchange (ETDEWEB)

    Agarwalla, Sanjib Kumar [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India)], E-mail: sanjib@hri.res.in; Choubey, Sandhya [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India)], E-mail: sandhya@hri.res.in; Raychaudhuri, Amitava [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India)], E-mail: raychaud@hri.res.in

    2008-12-11

    We examine the reach of a Beta-beam experiment with two detectors at carefully chosen baselines for exploring neutrino mass parameters. Locating the source at CERN, the two detectors and baselines are: (a) a 50 kton iron calorimeter (ICAL) at a baseline of around 7150 km which is roughly the magic baseline, e.g., ICAL-INO, and (b) a 50 kton Totally Active Scintillator Detector at a distance of 730 km, e.g., at Gran Sasso. We choose {sup 8}B and {sup 8}Li source ions with a boost factor {gamma} of 650 for the magic baseline while for the closer detector we consider {sup 18}Ne and {sup 6}He ions with a range of Lorentz boosts. We find that the locations of the two detectors complement each other leading to an exceptional high sensitivity. With {gamma}=650 for {sup 8}B/{sup 8}Li and {gamma}=575 for {sup 18}Ne/{sup 6}He and total luminosity corresponding to 5x(1.1x10{sup 18}) and 5x(2.9x10{sup 18}) useful ion decays in neutrino and antineutrino modes respectively, we find that the two-detector set-up can probe maximal CP violation and establish the neutrino mass ordering if sin{sup 2}2{theta}{sub 13} is 1.4x10{sup -4} and 2.7x10{sup -4}, respectively, or more. The sensitivity reach for sin{sup 2}2{theta}{sub 13} itself is 5.5x10{sup -4}. With a factor of 10 higher luminosity, the corresponding sin{sup 2}2{theta}{sub 13} reach of this set-up would be 1.8x10{sup -5}, 4.6x10{sup -5} and 5.3x10{sup -5} respectively for the above three performance indicators. CP violation can be discovered for 64% of the possible {delta}{sub CP} values for sin{sup 2}2{theta}{sub 13}{>=}10{sup -3} ({>=}8x10{sup -5}), for the standard luminosity (10 times enhanced luminosity). Comparable physics performance can be achieved in a set-up where data from CERN to INO-ICAL is combined with that from CERN to the Boulby mine in United Kingdom, a baseline of 1050 km.

  12. Numerical Analysis of Cavitation Processes in a Nozzle with Variable Cross-Section

    Directory of Open Access Journals (Sweden)

    N.L. Zagordan

    2013-09-01

    Full Text Available Numerical simulation approach addressing problems of cavitation processes and vapor-liquid two-phase flow dynamics research is discussed. The Navier-Stokes equations, supplemented by transport equation containing source terms, responsible for the interphase exchange, are solved to obtain hydrodynamic characteristics of the system. Mathematical model of unsteady conjugate heat-mass transfer between the bubble and the surrounding liquid is proposed to describe the evolution of a two-component (gas-vapor bubble. The model takes into account a spatial nonuniformity of the gas and liquid temperature fields as well as nonuniformity of the component concentration inside the bubble. A comparative analysis of the experimental data and computational results is carried out for different regimes of cavitating flows inside a two-dimensional nozzle with variable cross-section. The oscillation characteristics of hydrodynamic parameters and the gas-vapor bubbles behavior are investigated.

  13. Experimental Observations of Cavitating Flows Around a Hydrofoil

    Institute of Scientific and Technical Information of China (English)

    ZHANG Min-di; WANG Guo-yu; DONG Zi-qiao; LI Xiang-bin; GAO De-ming

    2008-01-01

    The cavitation around a hydrofoil is studied experimentally tO shed light on the multiphase fluid dynamies.Different cavitation regimes are studied by using high speed visualization and particle image velocimetry(PIV).As decreasing the cavitation number,four cavitating flow regimes are observed:incipient cavitation,sheet cavitation,cloud cavitation,and supercavitation.From the incipient cavitation to the cloud cavitation,bubbles become more and more.Phenomena with large-scale vortex structure and rear re-entrant jet associated with the cloud cavitation,and subsequent development in the supercavitation are described.The velocity in the cavitation regions in the different cavitation conditions is low compared to that of the free stream.The large velocity gradient is also observed in the cavitating flow region near the suHace of the hydrofoil.

  14. Stochastic-field cavitation model

    Energy Technology Data Exchange (ETDEWEB)

    Dumond, J., E-mail: julien.dumond@areva.com [AREVA Nuclear Professional School, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); AREVA GmbH, Erlangen, Paul-Gossen-Strasse 100, D-91052 Erlangen (Germany); Magagnato, F. [Institute of Fluid Mechanics, Karlsruhe Institute of Technology, Kaiserstrasse 12, D-76131 Karlsruhe (Germany); Class, A. [AREVA Nuclear Professional School, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Institute for Nuclear and Energy Technologies, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2013-07-15

    Nonlinear phenomena can often be well described using probability density functions (pdf) and pdf transport models. Traditionally, the simulation of pdf transport requires Monte-Carlo codes based on Lagrangian “particles” or prescribed pdf assumptions including binning techniques. Recently, in the field of combustion, a novel formulation called the stochastic-field method solving pdf transport based on Eulerian fields has been proposed which eliminates the necessity to mix Eulerian and Lagrangian techniques or prescribed pdf assumptions. In the present work, for the first time the stochastic-field method is applied to multi-phase flow and, in particular, to cavitating flow. To validate the proposed stochastic-field cavitation model, two applications are considered. First, sheet cavitation is simulated in a Venturi-type nozzle. The second application is an innovative fluidic diode which exhibits coolant flashing. Agreement with experimental results is obtained for both applications with a fixed set of model constants. The stochastic-field cavitation model captures the wide range of pdf shapes present at different locations.

  15. Stochastic-field cavitation model

    Science.gov (United States)

    Dumond, J.; Magagnato, F.; Class, A.

    2013-07-01

    Nonlinear phenomena can often be well described using probability density functions (pdf) and pdf transport models. Traditionally, the simulation of pdf transport requires Monte-Carlo codes based on Lagrangian "particles" or prescribed pdf assumptions including binning techniques. Recently, in the field of combustion, a novel formulation called the stochastic-field method solving pdf transport based on Eulerian fields has been proposed which eliminates the necessity to mix Eulerian and Lagrangian techniques or prescribed pdf assumptions. In the present work, for the first time the stochastic-field method is applied to multi-phase flow and, in particular, to cavitating flow. To validate the proposed stochastic-field cavitation model, two applications are considered. First, sheet cavitation is simulated in a Venturi-type nozzle. The second application is an innovative fluidic diode which exhibits coolant flashing. Agreement with experimental results is obtained for both applications with a fixed set of model constants. The stochastic-field cavitation model captures the wide range of pdf shapes present at different locations.

  16. Size effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2006-01-01

    In metal-ceramic systems the constraint on plastic flow leads to so high stress triaxialities that cavitation instabilities may occur. If the void radius is on the order of magnitude of a characteristic length for the metal, the rate of void growth is reduced, and the possibility of unstable cavi...... as the void grows to a size well above the characteristic material length....

  17. In Vivo Microbubble Cavitation Imaging

    NARCIS (Netherlands)

    Vignon, F.; Shi, W.; Liu, J.; Xie, F.; Gao, S.; Drvol, L.; Lof, J.; Everbach, C.; Porter, T.; Powers, J.

    2011-01-01

    Stroke is the second cause of death and leading cause of disabilityworldwide. Less than 5% of ischemic stroke patients receive the state-of-the art treatment of a thrombolytic drug tPA, and only about 10% of these gain additional benefit from it. Ultrasound (US)-inducedmicrobubble (MB) cavitation ha

  18. Test of a cryogenic set-up for a 10 meter long liquid nitrogen cooled superconducting power cable

    DEFF Research Database (Denmark)

    Træholt, Chresten; Rasmussen, Carsten; Kühle (fratrådt), Anders Van Der Aa

    2000-01-01

    cable. We report on our experimental set-up for testing a 10 meter long high temperature superconducting cable with a critical current of 3.2 kA at 77K. The set-up consists of a custom designed cable end termination, current lead, coolant feed-through, liquid nitrogen closed loop circulation system...

  19. Setting Up Simulations of Failure Scenarios for a Crab Cavity in the Nominal LHC

    CERN Document Server

    Yee, B

    2010-01-01

    The crab cavity (CC) represents a possible solution for the problem of the reduction of the luminosity due to a crossing angle. The CC apply a transversal kick on the beam particles that varies with the longitudinal position along the bunch in order to produce an effective head-head collision and to increase the geometry luminosity. For that reason the BE-ABP group at CERN has been performing studies for the implementation of the CC in the LHC. Because machine protection is a critical element of LHC operation, it is essential to study the failure scenarios of the superconducting crab cavity and the possible resulting damage impact and well as to find possible mitigation measures. For this purpose we set up simulation tools to model CC failures in the nominal LHC.

  20. Changxing Island in Dalian to Set up A World Class Petrochemical Park

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ In August 2008 "The Plan on Development of Petrochemi-cal Industry in Lingang Industry Area of Changxing Island in Dalian" had been assessed and approved by the expert team.According to this plan the Changxing Island will be basi-cally turned into a world-class Lingang petrochemical in-dustry park characterized by integration of oil refining and petrochemical sectors, and an industry intensive and eco-logical and environmentally friendly region. This industry park is scheduled to be developed in three phases to form in 15 years a national petrochemical base covering a total area of 25 km2. In the late "Eleventh Five-year Plan" period a region for development of specialty chemicals will be formed to prop up the low polluting, light and deep pro-cessing chemical sectors that can manufacture fine chemi-cals and new chemical materials to preliminarily set up a framework of petrochemical industry park.

  1. Investigations in quantum games using EPR-type set-ups

    CERN Document Server

    Iqbal, A

    2006-01-01

    Research in quantum games has flourished during recent years. However, it seems that opinion remains divided about their true quantum character and content. For example, one argument says that quantum games are nothing but 'disguised' classical games and that to quantize a game is equivalent to replacing the original game by a different classical game. The present thesis contributes towards the ongoing debate about quantum nature of quantum games by developing two approaches addressing the related issues. Both approaches take Einstein-Podolsky-Rosen (EPR)-type experiments as the underlying physical set-ups to play two-player quantum games. In the first approach, the players' strategies are unit vectors in their respective planes, with the knowledge of coordinate axes being shared between them. Players perform measurements in an EPR-type setting and their payoffs are defined as functions of the correlations, i.e. without reference to classical or quantum mechanics. Classical bimatrix games are reproduced if th...

  2. Three axis vector magnet set-up for cryogenic scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Galvis, J. A. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias Universidad Autónoma de Madrid, 28049 Madrid (Spain); Departamento de Ciencias Naturales Facultad de Ingeniería Universidad Central, Bogotá (Colombia); Herrera, E.; Buendía, A. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias Universidad Autónoma de Madrid, 28049 Madrid (Spain); Guillamón, I.; Vieira, S.; Suderow, H. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias Universidad Autónoma de Madrid, 28049 Madrid (Spain); Unidad Asociada de Bajas Temperaturas y Altos Campos Magnéticos, UAM, CSIC, Cantoblanco, E-28049 Madrid (Spain); Azpeitia, J.; Luccas, R. F.; Munuera, C.; García-Hernandez, M. [Unidad Asociada de Bajas Temperaturas y Altos Campos Magnéticos, UAM, CSIC, Cantoblanco, E-28049 Madrid (Spain); Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid (Spain); and others

    2015-01-15

    We describe a three axis vector magnet system for cryogenic scanning probe microscopy measurements. We discuss the magnet support system and the power supply, consisting of a compact three way 100 A current source. We obtain tilted magnetic fields in all directions with maximum value of 5T along z-axis and of 1.2T for XY-plane magnetic fields. We describe a scanning tunneling microscopy-spectroscopy (STM-STS) set-up, operating in a dilution refrigerator, which includes a new high voltage ultralow noise piezodrive electronics and discuss the noise level due to vibrations. STM images and STS maps show atomic resolution and the tilted vortex lattice at 150 mK in the superconductor β-Bi{sub 2}Pd. We observe a strongly elongated hexagonal lattice, which corresponds to the projection of the tilted hexagonal vortex lattice on the surface. We also discuss Magnetic Force Microscopy images in a variable temperature insert.

  3. Error control in the set-up of stereo camera systems for 3d animal tracking

    Science.gov (United States)

    Cavagna, A.; Creato, C.; Del Castello, L.; Giardina, I.; Melillo, S.; Parisi, L.; Viale, M.

    2015-12-01

    Three-dimensional tracking of animal systems is the key to the comprehension of collective behavior. Experimental data collected via a stereo camera system allow the reconstruction of the 3d trajectories of each individual in the group. Trajectories can then be used to compute some quantities of interest to better understand collective motion, such as velocities, distances between individuals and correlation functions. The reliability of the retrieved trajectories is strictly related to the accuracy of the 3d reconstruction. In this paper, we perform a careful analysis of the most significant errors affecting 3d reconstruction, showing how the accuracy depends on the camera system set-up and on the precision of the calibration parameters.

  4. Test and measurement procedures to set up the Quality-/Energy-Matrix for UPS

    Energy Technology Data Exchange (ETDEWEB)

    Schnyder, G.; Mauchle, P.

    2005-03-15

    This comprehensive report for the Swiss Federal Office of Energy (SFOE) is one of a set of nine reports that provide an overall review of the energy-efficiency of UPS systems. This report takes a look at the test and energy-measurement procedures necessary for the setting up of a quality/energy matrix. General definitions applicable to all measurements are defined along with specific test definitions and measurement criteria for specific faults and failures caused, for example, by variations in supply frequency and transients. Also considered are the measurement of power-factors and distortions as well as losses and efficiency. The report is completed with an appendix concerning standards along with the quality/energy matrix form itself.

  5. A set-up to measure the optical attenuation length of scintillating fibres

    CERN Document Server

    Alfieri, C; Joram, C

    2015-01-01

    The optical attenuation length of a scintillating fibre characterizes the quality of light transport through the fibre. It relates directly to the quantity of detectable light at the readout end of the fibre. An optical bench has been constructed, which allows excitation of the fibre at various distances from the photodetector. Depending on the choice of the photodetector – Si-PIN photodiode or grating spectrometer – the attenuation length is measured as weighted average over the sensitivity of the photodetector or as a spectral distribution. A few examples illustrate its operation and performance. The set-up serves for fibre optimisation in the R&D phase and is expected to be used for systematic checks during the series production phase of the LHCb SciFi tracker project.

  6. Opportunities for detecting ring currents using the attoclock set-up

    CERN Document Server

    Kaushal, Jivesh; Smirnova, Olga

    2015-01-01

    Strong field ionization by circularly polarized laser fields from initial states with internal orbital momentum has interesting propensity rule: electrons counter-rotating with respect to the laser field can be liberated more easily than co-rotating electrons [Barth and Smirnova PRA 84, 063415, 2011}]. Here we show that application of few-cycle IR pulses allows one to use this propensity rule to detect ring currents associated with such quantum states, by observing angular shifts of the ejected electrons. Such shifts present the main observable of the attoclock method. We use time-dependent Analytical $R$-Matrix (A$R$M) theory to show that the attoclock measured angular shifts of an electron originating from two counter-rotating orbitals ($p^{+}$ and $p^{-}$) are noticeably different. Our work opens new opportunities for detecting ring currents excited in atoms and molecules, using the attoclock set-up.

  7. Setting up a SLIP (serial line Internet protocol) server and Gopher site

    Science.gov (United States)

    Miller, Robert W. M.; Robin, Bernard

    1995-07-01

    The effort required to establish a communication facility that supports SLIP, PPP, Gopher, or other network services is substantial and cannot be undertaken without some background in TCP/IP networking and system administration. This paper provides a thumbnail sketch of the issues involved in setting up SLIP, PPP, and Gopher servers. It will familiarize the reader with the concepts underlying SLIP, compressed-SLIP, and PPP protocol, showing that they are examples of dial-up IP protocols. The paper will prepare the reader to develop an implementation plan for a dial-up IP facility suited to the communication infrastructure of their institution and relevant to the needs of their users. References to vendors and and sources of information are given throughout the chapter.

  8. PREDICTION OF PODDED PROPELLER CAVITATION USING AN UNSTEADY SURFACE PANEL METHOD

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The unsteady sheet cavitation of podded propeller was predicted by using a surface panel method. The interaction between propeller and pod was treated with the iterative calculation of induced velocity potential, and the method of induced velocity potential can save a great deal of storage and computation time compared to the method of induced velocity. The induced velocity potential of unit singularity on every pod panel to every key blade panel and of unit singularity on every key blade panel and its wake panel to every pod panel were calculated when the key blade is at every angle position. Based on the wake model of the conventional single propeller, a new wake model of podded propeller was constructed. The propeller is analyzed only on the key blade in order to save computation time and memory space. The method can be used to calculate the hydrodynamics performance and cavitation of propeller in uniform and non-uniform inflows. It can give the unsteady force and cavitation shape of propeller. The propeller cavitation range determined by the present method agrees with the observation results of cavity image given in cavitation tunnel well, and this proves the practicability of the method.

  9. Tangential breast irradiation; Influence of technique of set-up on transfer errors and reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Mitine, C.; Dutreix, A.; Van der Schueren, E. (University Hospital St. Rafael, Leuven (Belgium). Department of Radiotherapy)

    1991-12-01

    Using conventional portal films, the influence of the technique of set-up on the transfer error from simulator to treatment couch and on the subsequent reproducibility was made for the irradiated volume in the treatment of breast cancer. A total number of 376 portal films have been performed on 14 patients. All patients were treated on a 6MV Linac supplied with an automatic verification system excluding, however, the couch parameters. Overall precision of treatment delivery is evaluated by the global analysis of discrepancies between the simulator films and different portal films. For the patient group lying on a inclined plane with (group 2) or without (group 1) fixed arm support, narrow gaussian distribution is obtained in the anteroposterior (AP) direction with a SD of 4 mm. In the craniocaudal (CC) direction, distribution frequency of the patients treated without fixed arm support is mich larger than in the other group: SD is respectively 15.5mm for the first and 5.5mm for the second one. Reproducibility of the series of set-ups of the 2 groups estimated by reference to the mean value are similar in the AP direction. SD within the series of portal films in CC direction is 5.8 mm for the 1st group and 3.7 for the second. Their comparison with the discrepancies of 15.5 and 5.5mm when assessing the deviation between the stimulated and portal films shows the importance of systematic errors. Localisation of the irradiation port can be improved by using support systems with fixed arm indicators. (author). 6 refs.; 1 tab.

  10. Set Up of an Automatic Water Quality Sampling System in Irrigation Agriculture

    Science.gov (United States)

    Heinz, Emanuel; Kraft, Philipp; Buchen, Caroline; Frede, Hans-Georg; Aquino, Eugenio; Breuer, Lutz

    2014-05-01

    Climate change has already a large impact on the availability of water resources. Many regions in South-East Asia are assumed to receive less water in the future, dramatically impacting the production of the most important staple food: rice (Oryza sativa L.). Rice is the primary food source for nearly half of the World's population, and is the only cereal that can grow under wetland conditions. Especially anaerobic (flooded) rice fields require high amounts of water but also have higher yields than aerobic produced rice. In the past different methods were developed to reduce the water use in rice paddies, like alternative wetting and drying or the use of mixed cropping systems with aerobic (non-flooded) rice and alternative crops such as maize. A more detailed understanding of water and nutrient cycling in rice-based cropping systems is needed to reduce water use, and requires the investigation of hydrological and biochemical processes as well as transport dynamics at the field scale. New developments in analytical devices permit monitoring parameters at high temporal resolutions and at acceptable costs without much necessary maintenance or analysis over longer periods. Here we present a new type of automatic sampling set-up that facilitates in situ analysis of hydrometric information, stable water isotopes and nitrate concentrations in spatially differentiated agricultural fields. The system facilitates concurrent monitoring of a large number of water and nutrient fluxes (ground, surface, irrigation and rain water) in irrigated agriculture. For this purpose we couple an automatic sampling system with a Wavelength-Scanned Cavity Ring Down Spectrometry System (WS-CRDS) for stable water isotope analysis (δ2H and δ18O), a reagentless hyperspectral UV photometer for monitoring nitrate content and various water level sensors for hydrometric information. The whole system is maintained with special developed software for remote control of the system via internet. We

  11. Setting up of a cerebral visual impairment clinic for children: Challenges and future developments

    Science.gov (United States)

    Philip, Swetha Sara

    2017-01-01

    Aim: The aim of this study is to describe the setting up of a cerebral visual impairment (CVI) clinic in a tertiary care hospital in South India and to describe the spectrum of cases seen. Materials and Methods: The CVI clinic, set up in February 2011, receives interdisciplinary input from a core team involving a pediatrician, neurologist, psychiatrist, occupational therapist, pediatric ophthalmologist, and an optometrist. All children, <18 years of age, with cerebral palsy (CP), learning disability, autism, neurodegenerative diseases, and brain trauma are referred to the clinic for functional vision assessment and opinion for further management. Results: One thousand four hundred and seventy-eight patients were seen in the CVI clinic from February 2011 to September 2015. Eighty-five percent of the patients were from different parts of India. In the clinic, 61% had CP, 28% had seizure disorders, autism was seen in 9.5%, and learning disability, neurodegenerative conditions, and brain injury together constituted 1.5%. Most of the children (45%) had moderate CP. Forty percent of CVI was due to birth asphyxia, but about 20% did not have any known cause for CVI. Seventy percent of patients, who came back for follow-up, were carrying out the habilitation strategies suggested. Conclusions: Average attendance of over 300 new patients a year suggests a definite need for CVI clinics in the country. These children need specialized care to handle their complex needs. Although difficult to coordinate, an interdisciplinary team including the support groups and voluntary organizations is needed to facilitate the successful implementation of such specialized service. PMID:28300737

  12. Setting up and functioning of an Emergency Medicine Department: Lessons learned from a preliminary study

    Directory of Open Access Journals (Sweden)

    K Asish

    2016-01-01

    Full Text Available Background and Aims: Tertiary care teaching hospitals remain referral centres for victims of trauma and mass casualty. Often specialists from various disciplines manage these crowded casualty areas. These age old casualty areas are being replaced, throughout the country by Emergency Medicine Departments (EMDs, presumed to be better planned to confront a crisis. We aimed to gather basic data contributive in setting up of an EMD at a tertiary care teaching hospital from the lessons learned from functioning existent systems. Methods: This is primarily a questionnaire-based descriptive study at tertiary care referral centres across the country, which was purposively selected.The study models included one from a hospital without designated EMD and the other four from hospitals with established EMDs. Direct observation and focus group meetings with experienced informants at these hospitals contributed to the data. In the absence of a validated hospital preparedness assessment scale, comparison was done with regard to quantitative, qualitative and corroborative parameters using descriptive analysis. Results: The EMDs at best practice models were headed by specialist in Emergency Medicine assisted by organised staff, had protocols for managing mass casualty incident (MCI, separate trauma teams, ergonomic use of infrastructure and public education programmes. In this regard, these hospitals seemed well organised to manage MCIs and disasters. Conclusion: The observation may provide a preliminary data useful in setting up an EMD. In the absence of published Indian literature, this may facilitate further research in this direction. Anaesthesiologists, presently an approved Faculty in Emergency Medicine training can provide creative input with regard to its initial organisation and functioning, thus widening our horizons in a country where there is a severe dearth of trained emergency physicians.

  13. Registration of electronic portal images for patient set-up verification.

    Science.gov (United States)

    Matsopoulos, George K; Asvestas, Pantelis A; Delibasis, Konstantinos K; Kouloulias, Vassilios; Uzunoglu, Nikolaos; Karaiskos, Pantelis; Sandilos, Panagiotis

    2004-07-21

    Images acquired from an electronic portal imaging device are aligned with digitally reconstructed radiographs (DRRs) or other portal images to verify patient positioning during radiation therapy. Most of the currently available computer aided registration methods are based on the manual placement of corresponding landmarks. The purpose of the paper is twofold: (a) the establishment of a methodology for patient set-up verification during radiotherapy based on the registration of electronic portal images, and (b) the evaluation of the proposed methodology in a clinical environment. The estimation of set-up errors, using the proposed methodology, can be accomplished by matching the portal image of the current fraction of the treatment with the portal image of the baseline treatment (reference portal image) using a nearly automated technique. The proposed registration method is tested on a number of phantom data as well as on data from four patients. The phantom data included portal images that corresponded to various positions of the phantom on the treatment couch. For each patient, a set of 30 portal images was used. For the phantom data (for both transverse and lateral portal images), the maximum absolute deviations of the translational shifts were within 1.5 mm, whereas the in-plane rotation angle error was less than 0.5 degrees. The two-way Anova revealed no statistical significant variability both within observer and between-observer measurements (P > 0.05). For the patient data, the mean values obtained with manual and the proposed registration methods were within 0.5 mm. In conclusion, the proposed registration method has been incorporated within a system, called ESTERR-PRO. Its image registration capability achieves high accuracy and both intra- and inter-user reproducibility. The system is fully operational within the Radiotherapy Department of 'HYGEIA' Hospital in Athens and it could be easily installed in any other clinical environment since it requires

  14. The experimental set-up of the RIB in-flight facility EXOTIC

    Science.gov (United States)

    Pierroutsakou, D.; Boiano, A.; Boiano, C.; Di Meo, P.; La Commara, M.; Manea, C.; Mazzocco, M.; Nicoletto, M.; Parascandolo, C.; Signorini, C.; Soramel, F.; Strano, E.; Toniolo, N.; Torresi, D.; Tortone, G.; Anastasio, A.; Bettini, M.; Cassese, C.; Castellani, L.; Corti, D.; Costa, L.; De Fazio, B.; Galet, G.; Glodariu, T.; Grebosz, J.; Guglielmetti, A.; Molini, P.; Pontoriere, G.; Rocco, R.; Romoli, M.; Roscilli, L.; Sandoli, M.; Stroe, L.; Tessaro, M.; Zatti, P. G.

    2016-10-01

    We describe the experimental set-up of the Radioactive Ion Beam (RIB) in-flight facility EXOTIC consisting of: (a) two position-sensitive Parallel Plate Avalanche Counters (PPACs), dedicated to the event-by-event tracking of the produced RIBs and to time of flight measurements and (b) the new high-granularity compact telescope array EXPADES (EXotic PArticle DEtection System), designed for nuclear physics and nuclear astrophysics experiments employing low-energy light RIBs. EXPADES consists of eight ΔE -Eres telescopes arranged in a cylindrical configuration around the target. Each telescope is made up of two Double Sided Silicon Strip Detectors (DSSSDs) with a thickness of 40/60 μm and 300 μm for the ΔE and Eres layer, respectively. Additionally, eight ionization chambers were constructed to be used as an alternative ΔE stage or, in conjunction with the entire DSSSD array, to build up more complex triple telescopes. New low-noise multi-channel charge-sensitive preamplifiers and spectroscopy amplifiers, associated with constant fraction discriminators, peak-and-hold and Time to Amplitude Converter circuits were developed for the electronic readout of the ΔE stage. Application Specific Integrated Circuit-based electronics was employed for the treatment of the Eres signals. An 8-channel, 12-bit multi-sampling 50 MHz Analog to Digital Converter, a Trigger Supervisor Board for handling the trigger signals of the whole experimental set-up and an ad hoc data acquisition system were also developed. The performance of the PPACs, EXPADES and of the associated electronics was obtained offline with standard α calibration sources and in-beam by measuring the scattering process for the systems 17O+58Ni and 17O+208Pb at incident energies around their respective Coulomb barriers and, successively, during the first experimental runs with the RIBs of the EXOTIC facility.

  15. Anaesthesia in Congenital Facial Anomalies in a Rural Set up of a Developing Country

    Directory of Open Access Journals (Sweden)

    Debasish Saha

    2015-01-01

    Full Text Available Background: India has an estimated backlog of 1000000 cleft patients. A total of 35000 new cleft patients are born each year. With the capacity to operate on approximately 50000 patients each year only 15000 patients from the national backlog can be operated upon each year if capability is not augmented. Objectives: To reach the population at large we meticulously planned an out-reach programme and operated on patients even in rural set ups with lack of modern facilities. We operated on patients at sub divisional centres, where apparatus for providing sevoflurane was not available. Institutional Ethical clearance was taken before conduction of the study. Patients who required prolonged surgery were taken to the tertiary centre. Working ventilators were also not available at peripheral centres. Materials and Methods: This interventional study was carried in a time span of four years on nineteen hundred and nine patients, after taking approval from the Institutional Ethical Committee. Patients were screened and some were operated at rural centers and others at a tertiary care centre. Patients who could not afford to come to the tertiary care centre were operated at different rural centers. Informed consent was taken. Results: There were 1909 patients with Congenital Facial Anomalies (CFA over four years period out of which 918 patients were of either unilateral or bilateral cleft lip. They were successfully operated at rural health centers with limited facilities. This could reduce the total load of surgeries for CFA at tertiary care hospital ensuring safe surgeries for all with CFA for all age groups and both genders.No mortality was recorded and post operative complications consisted of nausea and vomiting, three had delayed recovery and one had laryngospasm. Conclusion: Outreach programmes can increase the efficacy of Smile Train Project and effective screening of patients before surgery can result in fruitful outcomes even in a rural set up

  16. Role of cavitation in the phacoemulsification process.

    Science.gov (United States)

    Zacharias, Jaime

    2008-05-01

    To determine the role of cavitational energy as a mechanism responsible for the emulsification of the lens during phacoemulsification. Clinica Ophthalmologica Pasteur, Santiago, Chile. Cavitation and its relationship to phacoemulsification power were documented using a combination of light sources, high-speed video recording techniques, and computerized control and by monitoring environmental pressure. The suppression of cavitation from the phaco process was achieved by building an environmental hyperbaric system capable of retaining the phacoemulsification system's ability to provide irrigation, aspiration, and vacuum necessary at standard and elevated pressures. The pressure level was controlled and monitored through a computer interface alongside the simultaneous video monitoring of cavitation bubble creation changes during pressure rise or fall. Last, evaluation and measurement of phacoemulsification was performed on real cataract fragments in the presence and absence of cavitation. Cavitation around the phaco tip mainly occurred at longitudinal ultrasonic power levels of 30% or more. Cavitation bubble formation was observed during the backstroke or as the tip moved away from the lens material and collapsed during the forward displacement of the phaco tip. Cavitation at any power level was successfully suppressed when the pressure in the hyperbaric chamber increased beyond 2.0 bar (29.1 psi) above atmospheric pressure. Phacoemulsification performance in the presence or absence of cavitation was comparable. This study found strong evidence that cavitation plays no role in phacoemulsification, leaving the jackhammer effect as the only important mechanism responsible for the lens-disrupting power of phacoemulsification.

  17. Introduction to Hydrodynamics

    CERN Document Server

    Jeon, Sangyong

    2015-01-01

    We give a pedagogical review of relativistic hydrodynamics relevant to relativistic heavy ion collisions. Topics discussed include linear response theory derivation of 2nd order viscous hydrodynamics including the Kubo formulas, kinetic theory derivation of 2nd order viscous hydrodynamics, anisotropic hydrodynamics and a brief review of numerical algorithms. Emphasis is given to the theory of hydrodynamics rather than phenomenology.

  18. Numerical Investigation Cavitation Buckets for Hydrofoil Parametrically

    Directory of Open Access Journals (Sweden)

    Mehmet Salih KARAALİOĞLU

    2015-12-01

    Full Text Available Cavitation is a general fluid mechanics phenomenon that is appeared in system such as pumps, turbines, marine propellers and hydrofoils which induces pressure and velocity fluctuation in the fluid (Brennen, 2013. Cavitation can be defined as the formation of vapour regions due to a decrease in local pressure. Undesirable consequences which can cause a fall in the performance of a system, structural failure, production of noise and vibration, material damage, are encountered due to cavitation (Uşar, 2015. In this study, cavitation was analysed using a bucket diagram. Bucket diagram represents the cavitation behaviour of a wing, fin or propeller blade in a two dimensional sense. This diagram is plotted as a function of section (hydrofoil angle of attack (α versus section cavitation number (σ. Pressure distribution can be calculated on two dimensional geometry of hydrofoil by using BEM (Boundary Element Method and cavitation bucket diagram can be computed. The cavitation inception case and partial cavitation cases have been investigated and the results of the present BEM were successfully compared with those of given in literature in the past and each other. While a constant source-dipole panel method has been used to calculate the pressure distribution at cavitation inception case, PCPAN programme that solves the sheet type of cavity on the hydrofoil by potential based panel method, has been used to calculate pressure distribution for the cases of partial cavitation. Effects of maximum hydrofoil thickness, maximum camber and location of maximum camber on cavitation have been analyzed by means of cavitation bucklet diagrams. All results are discussed in a detailed manner.

  19. River Modeling in Large and Ungauged Basins: Experience of Setting up the HEC RAS Model over the Ganges-Brahmaputra-Meghna Basins

    Science.gov (United States)

    Hossain, F.; Maswood, M.

    2014-12-01

    River modeling is the processing of setting up a physically-based hydrodynamic model that can simulate the water flow dynamics of a stream network against time varying boundary conditions. Such river models are an important component of any flood forecasting system that forecasts river levels in flood prone regions. However, many large river basins in the developing world such as the Ganges, Brahmaputra, Meghna (GBM), Indus, Irrawaddy, Salween, Mekong and Niger are mostly ungauged. Such large basins lack the necessary in-situ measurements of river bed depth/slope, bathymetry (river cross section), floodplain mapping and boundary condition flows for forcing a river model. For such basins, proxy approaches relying mostly on remote sensing data from space platforms are the only alternative. In this study, we share our experience of setting up the widely-used 1-D river model over the entire GBM basin and its stream network. Good quality in-situ measurements of river hydraulics (cross section, slope, flow) was available only for the downstream and flood prone region of the basin, which comprises only 7% of the basin area. For the remaining 93% of the basin area, we resorted to the use of data from the following satellite sensors to build a workable river model: a) Shuttle Radar Topography Mission (SRTM) for deriving bed slope; b) LANDSAT/MODIS for updating river network and flow direction generated by elevation data; c) radar altimetry data to build depth versus width relationship at river locations; d) satellite precipitation based hydrologic modeling of lateral flows into main stem rivers. In addition, we referred to an extensive body of literature to estimate the prevailing baseline hydraulics of rivers in the ungauged region. We measured success of our approach by systematically testing how well the basin-wide river model could simulate river level dynamics at two measured locations inside Bangladesh. Our experience of river modeling was replete with numerous

  20. SETTING UP OF A HOMECARE SYSTEM FOR HIGH COST NEBULISERS IN A PAEDIATRIC CYSTIC FIBROSIS CENTRE.

    Science.gov (United States)

    Chorro-Mari, Veronica; Christiansen, Nanna

    2016-09-01

    Due to national changes to the commissioning process of high cost nebulisers (HCN) for Cystic Fibrosis (CF) patients, CF centres have to repatriate the prescribing of the HCN to the tertiary care centres.1 The following nebulisers will no longer be prescribed by primary care: Cayston® (Aztreonam); Colomycin®, Pomixin®, Clobreathe® (Colistimethate); Pulmozyme® (Dornase alfa); Tobi®, Tobi Podhaler ®, Bramitob® (Tobramycin).This abstract explains how the Royal London Hospital (RLH) Paediatric Pharmacy recruited over 100 paediatric (CF) patients smoothly within a period of 4 months and set up a homecare system to avoid patients and families having to travel large distances to obtain their medication. A number of homecare companies were evaluated initially. Parameters looked at were reports of customer satisfaction, delivery cost, turn-around time once the prescription was received and availability of same day delivery service.In order to capture existing patients we met with CF Specialist Nurses to establish the total number of patients on HCN, what nebulised treatment they were on and their respective doses. We prioritised patients that had known problems with GP prescribing and anybody newly starting on HCN.To communicate the change to parents, a letter was sent to all parents explaining the changeover to homecare delivery and tertiary prescribing. In addition a section in the parent bulletin was dedicated to the topic as well. Following this we contacted parents via phone and in clinic to request consent and explain the process.Up to 10 patients were contacted weekly (average of 7); the consent form and registration form were then faxed to the Homecare company for patient registration. In parallel to this prescriptions were requested for the patients that had been set up in the previous week, ensuring that prescribing was spread out over time to avoid having peak times for repeat prescriptions.In addition to the letter to parents GP surgeries were also

  1. Prediction of cryogenic cavitation around hydrofoil by an extensional Schnerr-Sauer cavitation model

    Science.gov (United States)

    Sun, T. Z.; Wei, Y. J.; Wang, C.

    2015-12-01

    Developing a robust computational strategy to address the rich physics characteristic involved in the thermodynamic effects on the cryogenic cavitation remains a challenging problem. The objective of this present study is to model the numerical methodology to simulate the cryogenic cavitation by implanting the thermodynamic effects to the Schnerr-Sauer cavitation model, and coupling the energy equation considered the latent heat. For this purpose, cavitating flows are investigated over a three dimensional hydrofoil in liquid hydrogen and nitrogen. Experimental measurements of pressure and temperature are utilized to validate the extensional Schnerr-Sauer cavitation model. Specifically, the further analysis of the cavitation solution with respect to the thermodynamic term is conducted. The results show that the extensional Schnerr-Sauer cavitation model predicts better accuracy to the quasi-steady cavitation over hydrofoil in the two cryogenic fluids.

  2. Development of a new set-up mathematical model for the tandem hot rolling unit of the brazilian National Steel Company; Desenvolvimento de novo modelo matematico de set up do LTQ-2 da CSN

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Aquiles A. da; Dornelas, Francisco C.; Tirello, Jonas; Brandao, Jose M.M. [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil)

    1991-12-31

    This paper shows the development of a set-up mathematical model for the tandem hot rolling unit of the brazilian National Steel Company, specifically for the cylinder opening and chair speed. 2 refs., 10 figs.

  3. Numerical 3D flow simulation of ultrasonic horns with attached cavitation structures and assessment of flow aggressiveness and cavitation erosion sensitive wall zones.

    Science.gov (United States)

    Mottyll, Stephan; Skoda, Romuald

    2016-07-01

    As a contribution to a better understanding of cavitation erosion mechanisms, a compressible inviscid finite volume flow solver with barotropic homogeneous liquid-vapor mixture cavitation model is applied to ultrasonic horn set-ups with and without stationary specimen, that exhibit attached cavitation at the horn tip. Void collapses and shock waves, which are closely related to cavitation erosion, are resolved. The computational results are compared to hydrophone, shadowgraphy and erosion test data. At the horn tip, vapor volume and topology, subharmonic oscillation frequency as well as the amplitude of propagating pressure waves are in good agreement with experimental data. For the evaluation of flow aggressiveness and the assessment of erosion sensitive wall zones, statistical analyses of wall loads and of the multiplicity of distinct collapses in wall-adjacent flow regions are applied to the horn tip and the stationary specimen. An a posteriori projection of load collectives, i.e. cumulative collapse rate vs. collapse pressure, onto a reference grid eliminates the grid dependency effectively for attached cavitation at the horn tip, whereas a significant grid dependency remains at the stationary specimen. The load collectives show an exponential decrease towards higher collapse pressures. Erosion sensitive wall zones are well predicted for both, horn tip and stationary specimen, and load profiles are in good qualitative agreement with measured topography profiles of eroded duplex stainless steel samples after long-term runs. For the considered amplitude and gap width according to ASTM G32-10 standard, the analysis of load collectives reveals that the distinctive erosive ring shape at the horn tip can be attributed to frequent breakdown and re-development of a small portion of the tip-attached cavity. This partial breakdown of the attached cavity repeats at each driving cycle and is associated with relatively moderate collapse peak pressures, whereas the

  4. Submarine hydrodynamics

    CERN Document Server

    Renilson, Martin

    2015-01-01

    This book adopts a practical approach and presents recent research together with applications in real submarine design and operation. Topics covered include hydrostatics, manoeuvring, resistance and propulsion of submarines. The author briefly reviews basic concepts in ship hydrodynamics and goes on to show how they are applied to submarines, including a look at the use of physical model experiments. The issues associated with manoeuvring in both the horizontal and vertical planes are explained, and readers will discover suggested criteria for stability, along with rudder and hydroplane effectiveness. The book includes a section on appendage design which includes information on sail design, different arrangements of bow planes and alternative stern configurations. Other themes explored in this book include hydro-acoustic performance, the components of resistance and the effect of hull shape. Readers will value the author’s applied experience as well as the empirical expressions that are presented for use a...

  5. A simple, low-cost and fast Peltier thermoregulation set-up for electrophysiology.

    Science.gov (United States)

    Corrèges, P; Bugnard, E; Millerin, C; Masiero, A; Andrivet, J P; Bloc, A; Dunant, Y

    1998-09-01

    Most of the parameters recorded in electrophysiology are strongly temperature dependent. In order to control temperature fluctuations we have built a system that ensures an accurate thermoregulation of the recording chamber. Temperature of physiological preparations can be changed relatively quickly (about 8 degrees C/min) and with a good accuracy (+/- 0.5 degrees C) without inducing thermal oscillations. Contrary to other thermoregulating devices, the temperature regulation is not carried out through the perfused medium but directly at the bottom of the chamber where a 3-cm2 Peltier element has been placed. The element is driven by a dedicated electronic device which controls the amount and the direction of the current flowing across the Peltier thermocouple. All construction details and the appropriate electrical circuits are provided. Using this home-made device, the steady-state chamber temperature could be precisely monitored with a resolution of +/- 0.1 degrees C in a range of 0-40 degrees C. This set-up was tested in experiments designed to evaluate the temperature dependence of synaptic transmission in the Torpedo nerve electroplate synapses and of calcium currents recorded from isolated nerve cells. This low-cost method is suitable for a wide range of applications.

  6. New large solar photocatalytic plant: set-up and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Malato, S.; Blanco, J.; Vidal, A.; Fernandez, P.; Caceres, J. [Plataforma Solar de Almeria (Spain); Trincado, P. [HIDROCEN, Madrid (Spain); Oliveira, J.C. [AOSOL, Samora-Corria (Portugal); Vincent, M. [ECOSYSTEM S.A., Barcelona (Spain)

    2002-04-01

    A European industrial consortium called SOLARDETOX has been created as the result of an EC-DGXII BRITE-EURAM-III-financed project on solar photocatalytic detoxification of water. The project objective was to develop a simple, efficient and commercially competitive water-treatment technology, based on compound parabolic collectors (CPCs) solar collectors and TiO{sub 2} photocatalysis, to make possible easy design and installation. The design, set-up and preliminary results of the main project deliverable, the first European industrial solar detoxification treatment plant, is presented. This plant has been designed for the batch treatment of 2 m{sup 3} of water with a 100 m{sup 2} collector-aperture area and aqueous aerated suspensions of polycrystalline TiO{sub 2} irradiated by sunlight. Fully automatic control reduces operation and maintenance manpower. Plant behaviour has been compared (using dichloroacetic acid and cyanide at 50 mgl{sup -1} initial concentration as model compounds) with the small CPC pilot plants installed at the Plataforma Solar de Almeria several years ago. The first results with high-content cyanide (1 gl{sup -1}) waste water are presented and plant treatment capacity is calculated. (author)

  7. Set-up and preliminary performance of a digital radiology conference system

    Institute of Scientific and Technical Information of China (English)

    王学建; 胡建; 曹军; 王波; 焦俊; 魏渝清; 王小林; 罗敏; 罗松

    2003-01-01

    Objective To investigate the set-up and preliminary performance of a digital radiology conference system and its characteristics. Methods The imaging system included a dual-screen image-text workstation with a Matrox G450 demonstration dual-head card, two multimedia projectors, a large screen, and a line-pair and grey scale test card. Patient information on radiology information system (RIS) and images on picture archiving and communication system (PACS) were fetched with GE Radworks software based on Intranet and PACS. The fetching velocity and resolution and grey scale of the images were measured. Results Patient information in the form of texts and images were demonstrated successfully on two screens with Matrox G450 demonstration dual-head card and switched rapidly between text-image two-screen and image two-screen. The image fetching velocity was fast, the resolution was high, and the grey scale was good. Conclusion The digital conference radiology system is good, and should be popularized.

  8. TEST BEAM COORDINATION: The 2004 Test Beam Calorimetry set-up in H8

    CERN Multimedia

    Aleksa, M; Di Girolamo, B; Ferrari, C; Giugni, D; Santoni, C; Wingerter, I

    A new table has been designed, built and finally mounted to position the LAr cryostat in front of the Tilecal modules. The new table has been connected to the existing Tilecal table to be able to move the full set-up along eta values between 0 and 1.2. The table has been conceived by D. Giugni (INFN Milano and now CERN PH) and modeled by G. Braga (INFN Milano) in spring-summer 2003. The realization of the table has been done by an Italian firm (MatecImpianti, Fenegrò, Como) under the supervision of S. Coelli (INFN Milano) starting August 2003. Figure 1 shows the table assembled at the firm (left). Figure 1: The Tilecal-LAr table: in Fenegro (left) and at CERN (right). In November 2003 the table has been delivered to CERN and put in temporary storage to be assembled after the preparation of the Tilecal zone. In February 2004 two technicians from the firm and the team of technician coordinated by C. Ferrari (CERN AB/ATB), assembled, tested and commissioned the table under the supervision of S. Coelli...

  9. Impedance measurement set-up based on off-the-shelf PXI modules

    Science.gov (United States)

    Pettersen, F. J.; Martinsen, Ø. G.; Grimnes, S.; Høgetveit, J. O.

    2010-04-01

    As bioimpedance measurements are being done in an increasing variety of measurands and environments, measurement equipment must be flexible in use and easy to handle for the researcher. Measurement equipment used today is excellent for a range of uses, but it is often bulky, heavy, and not very flexible. A new compact and flexible measurement set-up based on off-the-shelf modules is described. The system is based on commercially available PXI-modules, one module that may be custom made, and custom software. The basis of the system is a PXI chassis with a power supply unit. The chassis is equipped with a controller module running software controlling the system, a signal generator, and a multichannel digitizer. All of this is commercially available. Both a custom made and a commercially available impedance interfaces were used. A LabVIEW program is controlling the measurement system, and provides a user interface. The LabVIEW program handles necessary signal conditioning and calibration. The measurement system is capable of doing frequency response measurements at frequencies up to 15 MHz. In addition to the two normal voltage pick-up electrodes used in four-electrode measurements, this system has the possibility to use 5 extra voltage pick-up electrodes. This simplifies exploration of segmental impedance, anisotropy, reciprocity, etc.

  10. [Set up of a protocol for heparin use in special patients].

    Science.gov (United States)

    Manresa Ramón, N; Nájera Pérez, Ma D; Page del Pozo, Ma Ángeles; Sánchez Martínez, I; Sánchez Catalicio, Ma del M; Roldán Schilling, V

    2014-04-01

    Low-molecular weight (LMW) heparins bring a series of advantages as compared to non-fractionated heparin (NFH), such as safety, efficacy, bioavailability, fewer monitoring, and persistent anti-coagulant response. There exist, however, a concern about their use in particular patients that may require a special control, such as those with renal failure, age over 75 years, obesity, and pregnancy. The aim of this study was the set up between the department of Pharmacy, Hematology, and Internal Medicine of a consensus protocol for the follow-up ad monitoring of LMWH in patients requiring a special control. For this purpose, we carried out a bibliographical review of the different heparins used under de above mentioned conditions. Based on the evidence available and the consensus among the members of the working group, we established a protocol that contained recommendations on prophylaxis, management and monitoring by means of the determination of anti-Xa factor. Besides, we included some clues on the therapeutic figures of anti-Xa and administration schedules for obtaining anti-Xa values within the range. Enoxaparin was the selected heparin given the evidence and its availability at our center.

  11. A set-up for a biased electrode experiment in ADITYA Tokamak

    Science.gov (United States)

    Dhyani, Pravesh; Ghosh, Joydeep; Sathyanarayana, K.; Praveenlal, V. E.; Gautam, Pramila; Shah, Minsha; Tanna, R. L.; Kumar, Pintu; Chavda, C.; Patel, N. C.; Panchal, V.; Gupta, C. N.; Jadeja, K. A.; Bhatt, S. B.; Kumar, S.; Raju, D.; Atrey, P. K.; Joisa, S.; Chattopadhyay, P. K.; Saxena, Y. C.

    2014-10-01

    An experimental set-up to investigate the effect of a biased electrode introduced in the edge region on ADITYA tokamak discharges is presented. A specially designed double-bellow mechanical assembly is fabricated for controlling the electrode location as well as its exposed length inside the plasma. The cylindrical molybdenum electrode is powered by a capacitor-bank based pulsed power supply (PPS) using a semiconductor controlled rectifier (SCR) as a switch with forced commutation. A Langmuir probe array for radial profile measurements of plasma potential and density is fabricated and installed. Standard results of improvement of global confinement have been obtained using a biased electrode. In addition to that, in this paper we show for the first time that the same biasing system can be used to avoid disruptions through stabilisation of magnetohydrodynamic (MHD) modes. Real time disruption control experiments have also been carried out by triggering the bias-voltage on the electrode automatically when the Mirnov probe signal exceeds a preset threshold value using a uniquely designed electronic comparator circuit. Most of the results related to the improved confinement and disruption mitigation are obtained in case of the electrode tip being kept at ~3 cm inside the last closed flux surface (LCFS) with an exposed length of ~20 mm in typical discharges of ADITYA tokamak.

  12. Exceptional Sensitivity to Neutrino Parameters with a Two Baseline Beta-Beam Set-up

    CERN Document Server

    Agarwalla, Sanjib Kumar; Raychaudhuri, Amitava

    2008-01-01

    We examine the reach of a Beta-beam experiment with two detectors at carefully chosen baselines for exploring neutrino mass parameters. Locating the source at CERN, the two detectors and baselines are: (a) a 50 kton iron calorimeter (ICAL) at a baseline of around 7150 km which is roughly the magic baseline, e.g., ICAL@INO, and (b) a 50 kton Totally Active Scintillator Detector at a distance of 730 km, e.g., at Gran Sasso. We choose 8B/8Li source ions with a boost factor \\gamma of 650 for the magic baseline while for the closer detector we consider 18Ne/6He ions with a range of Lorentz boosts. We find that the locations of the two detectors complement each other leading to an exceptional high sensitivity. With \\gamma=650 for 8B/8Li and \\gamma=575 for 18Ne/6He and total luminosity corresponding to 5\\times (1.1 \\times 10^{18}) and 5\\times (2.9\\times 10^{18}) useful ion decays in neutrino and antineutrino modes respectively, we find that our two detector set-up can probe maximal CP violation and establish the neu...

  13. Probabilistic multiscale image segmentation: set-up and first results (Proceedings Only)

    Science.gov (United States)

    Vincken, Koen L.; Koster, Andre S.; Viergever, Max A.

    1992-09-01

    We have developed a method to segment two- and three-dimensional images using a multiscale (hyperstack) approach with probabilistic linking. A hyperstack is a voxel-based multiscale data structure containing linkages between voxels at different scales. The scale-space is constructed by repeatedly applying a discrete convolution with a Gaussian kernel to the original input image. Between these levels of increasing scale we establish child-parent linkages according to a linkage scheme that is based on affection. In the resulting tree-like data structure roots are formed to indicate the most plausible locations in scale-space where objects (of different sizes) are actually defined by a single voxel. Tracing the linkages back from every root to the ground level produces a segmented image. The present paper deals with probabilistic linking, i.e., a set-up in which a child voxel can be linked to more than one parent voxel. The output of the thus constructed hyperstack -- a list of object probabilities per voxel -- can be directly related to the opacities used in volume renderers.

  14. Set up and application of an underwater Α-ray spectrometer for radioactivity measurements

    Directory of Open Access Journals (Sweden)

    C. TSABARIS

    2012-12-01

    Full Text Available The set up and control of an underwater measuring instrument for radioactivity pollution in the marine environment is described. The detection system is based on a NaI scintillator (RADAM III with modifications for use in the marine environment with on-line measurements. The system is simple, has low power consumption and is stable for long-term monitoring (10 months. Before its deployment, the sensor was calibrated in the laboratory in a tank full of water to reproduce the marine environment. The calibrations were performed, by detecting the 661keV and 1461 keV gamma rays of known activity liquid sources 137 Cs and 40 K, respectively. The measured spectra in the laboratory were compared with spectra from a similar detector as acquired in the field. The analysis of the parallel measurement gave satisfactory agreement for the concentration of the potassium (40 K, as calculated from the salinity in the seawater, thus enabling the system for quantitative measurement of the seawater radioactivity.

  15. Ultra-sensitive γ-ray spectroscopy set-up for investigating primordial lithium problem

    Energy Technology Data Exchange (ETDEWEB)

    Gervino, G., E-mail: gervino@to.infn.it [Dipartimento di Fisica, Universitá di Torino and INFN Torino (Italy); Gustavino, C. [INFN Sezione di Roma La Sapienza, Roma (Italy); Trezzi, D. [Dipartimento di Fisica, Universitá di Milano and INFN Milano (Italy); Aliotta, M. [SUPA, School of Physics and Astronomy, University of Edinburgh (United Kingdom); Anders, M. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Boeltzig, A. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Bemmerer, D. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Best, A. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Broggini, C. [Dipartimento di Fisica e Astronomia, Universitá di Padova and INFN Padova (Italy); Bruno, C. [SUPA, School of Physics and Astronomy, University of Edinburgh (United Kingdom); Caciolli, A. [Dipartimento di Fisica e Astronomia, Universitá di Padova and INFN Padova (Italy); Cavanna, F.; Corvisiero, P. [Dipartimento di Fisica, Universitá di Genova and INFN Genova (Italy); Davinson, T. [SUPA, School of Physics and Astronomy, University of Edinburgh (United Kingdom); Depalo, R. [Dipartimento di Fisica e Astronomia, Universitá di Padova and INFN Padova (Italy); DiLeva, A. [Seconda Universitá di Napoli, Caserta and INFN Napoli (Italy); Elekes, Z. [Institute of Nuclear Research ATOMKI, Debrecen (Hungary); Ferraro, F. [Dipartimento di Fisica, Universitá di Genova and INFN Genova (Italy); Formicola, A. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Fülöp, Zs. [Institute of Nuclear Research ATOMKI, Debrecen (Hungary); and others

    2016-07-11

    To precisely determine BBN {sup 6}Li production, the cross-section of the nuclear reaction {sup 2}H(α, γ){sup 6}Li must be directly measured within the astrophysical energy range of 30–400 keV. This measure requires an ultra-low γ-ray background in the experimental set-up. We have realized the conditions matching these very strict requirements at LUNA, the deep underground accelerator laboratory active in the INFN Gran Sasso National Laboratory (LNGS), Italy: the γ-ray spectrometer background has been reduced down to reach unmatched low levels, comparable to the good ones experienced in dedicated off-line underground ultra low γ counting rate. We present and discuss the γ-ray background reduction reached in the HpGe spectrometer, where most of the remaining γ-ray background seen in the spectra are coming from the energetic deuterons scattered in the gas target by the α beam. Thanks to the low neutron environmental background at LUNA, the effect of this weak flux of 2–3 MeV neutrons on HpGe detectors has been studied in details and the results are presented and discussed.

  16. HUG sets up an emergency operations centre on the CERN site

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    Discussions between CERN and the Hôpitaux universitaires de Genève (HUG), under the aegis of the Swiss authorities, have resulted in the setting-up of an emergency operations centre on the CERN site. This will be the operations base for an emergency doctor, a medical emergency vehicle and a driver. Located on the Swiss part of the Meyrin site, close to Building 57, it will be inaugurated on 20 May.   SMUR team based at CERN. CERN’s medical staff and fire-fighters dispense first aid but in medical emergencies they are obliged to call on outside services to treat and transfer patients to hospital. In the Canton of Geneva, this service is provided by HUG via the 144 emergency line. But HUG is based on the eastern side of Geneva, a long way from CERN, and response times can be substantial. In order to improve the safety of the growing number of people on the site, CERN asked Switzerland, as one of its Host States, to help it reduce the medical emergency response t...

  17. Investigation of Boundary Effects on the Natural Cavitating Flow around a 2D Wedge in Shallow Water

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2011-01-01

    Full Text Available When a cavitated body moves in shallow water, both flexible free surface and rigid bottom wall will produce great influence on the cavity pattern and hydrodynamics to change the motion attitude and stability of the body. In this paper, a single-fluid multiphase flow method coupled with a natural cavitation model was employed to study the effects of two kinds of boundaries on the natural cavitating flow around a two-dimensional symmetry wedge in shallow water. Within the range of the cavitation number for computation (0.05 ~ 2.04, the cavity pattern would be divided into three types, namely, stable type, transition type and wake-vortex type. The shape of the free surface is fairly similar to that of the cavity's upper surface with well right-and-left symmetry. However, when the immersion depth and the cavitation number are decreasing, the symmetry of the cavity shape is destroyed due to the influence of bottom wall effects. When the cavitation number is less than about 0.1, with the immersion depth going down, free surface effects exerts a stronger influence on the drag coefficient of this 2D wedge, whereas wall effects bring a stronger influence on the lift coefficient.

  18. Cavitation study of a pump-turbine at turbine mode with critical cavitation coefficient condition

    Science.gov (United States)

    Wang, J.; Yang, D.; Xu, J. W.; Liu, J. T.; Jiao, L.

    2016-05-01

    To study the cavitation phenomenon of a pump-turbine at turbine mode when it ran at the critical cavitation coefficient condition, a high-head model pump-turbine was disperse using hexahedron grid. Three dimensional, steady cavitating flow was numerically studied using SST k-ω model. It is confirmed that ZGB cavitation model and SST k-ω model are useful ways to study the two-phase cavitation flow in pump-turbine. Mass flow inlet and pressure outlet were specified at the casing inlet and draft tube outlet, respectively. The static pressure was set according to the cavitation coefficient. The steady cavitating flows at critical cavitation coefficient condition were analysed. The cavitation area in the runner was investigated. It was found that the pressure of the suction on the blade surface was decreasing gradually with the decrease of the cavitation coefficient. In addition, the vortex flow in the draft tube was observed at the critical cavitation coefficient. It was found that the vortex flow appeared at the center of the draft tube inlet with the decreasing of the cavitation coefficient. Compared with the experimental data, the simulation results show reasonable agreement with the experimental data.

  19. Memory-Effect on Acoustic Cavitation

    OpenAIRE

    Yavaṣ, Oğuz; Leiderer, Paul; Park, Hee K.; Grigoropoulos, Costas P.; Poon, Chie C.; Tam, Andrew C.

    1994-01-01

    The formation of bubbles at a liquid-solid interface due to acoustic cavitation depends particularly on the preconditions of the interface. Here, it wiIl be shown that following laser-induced bubble formation at the interface the acoustic cavitation efficiency is strongly enhanced. Optical reflectance measurements reveal that this observed enhancement of acoustic cavitation due to preceding laser-induced bubble formation, which could be termed as memory effect, decays in a few hundred microse...

  20. Measuring Dynamic Transfer Functions of Cavitating Pumps

    Science.gov (United States)

    Baun, Daniel

    2007-01-01

    A water-flow test facility has been built to enable measurement of dynamic transfer functions (DTFs) of cavitating pumps and of inducers in such pumps. Originally, the facility was intended for use in an investigation of the effects of cavitation in a rocket-engine low-pressure oxygen turbopump. The facility can also be used to measure DTFs of cavitating pumps in general

  1. The domain of validity of fluid dynamics and the onset of cavitation in ultrarelativistic heavy ion collisions

    CERN Document Server

    Denicol, Gabriel S; Jeon, Sangyong

    2015-01-01

    If the bulk viscosity of QCD matter is large, the effective pressure of the hot and dense matter created in ultrarelativistic heavy ion collisions can become negative, leading to instabilities in the evolution of the plasma. In the context of heavy ion collisions, this effect is sometimes referred to as cavitation. In this contribution we discuss the onset of cavitation in event-by-event hydrodynamic simulations of ultrarelativistic heavy ion collisions at LHC energies. We estimate how large the bulk viscosity of the QGP has to be in the QCD (pseudo) phase transition region in order for the effective pressure of the system to actually become negative.

  2. Mesenteric lymph node cavitation syndrome

    Institute of Scientific and Technical Information of China (English)

    Hugh; James; Freeman

    2010-01-01

    The mesenteric lymph node cavitation syndrome consists of central necrosis of mesenteric lymph nodes and may occur with either celiac disease or a sprue-like intestinal disease that fails to respond to a gluten-free diet. Splenic hypofunction may also be present. The cause is not known but its development during the clinical course of celiac disease is usually indicative of a poor prognosis for the intestinal disorder, a potential for signif icant compli-cations including sepsis and malignancy, particularly...

  3. Acoustic Cavitation and Bubble Dynamics.

    Science.gov (United States)

    1985-06-15

    Achilles tendon of a cow. Presently ceramic piezoelectrics are widely used to generate ultrasonic signals, as they are relatively inexpensive and can...the application of a negative pressure could result in a rupture of the liquid while d’Alembert refused to accept this view. The rise of cavitation as a...contraction resulted in the liquid undergoing a tensile stress, eventually ending in the rupture of the liquid. The temperature at which rupture occurred was

  4. Breaking beer bottles with cavitation

    Science.gov (United States)

    Jung, Sunny; Fontana, Jake; Palffy-Muhoray, Peter; Shelley, Michael

    2009-03-01

    Hitting the top of a beer bottle, nearly full of water, with an open hand can cause the bottle to break, with the bottom separating from upper section. We have studied this phenomenon using a high-speed camera, and observed the formation, coalescence and collapse of bubbles. The breaking of glass is due to cavitation, typically occurring near the bottom edge. We make numerical estimates of the relevant physical parameters, and compare these with experimental observations.

  5. Cavitation on hydrofoils with sinusoidal leading edge

    Science.gov (United States)

    Johari, H.

    2015-12-01

    Cavitation characteristics of hydrofoils with sinusoidal leading edge were examined experimentally at a Reynolds number of 7.2 × 105. The hydrofoils had an underlying NACA 634-021 profile and an aspect ratio of 4.3. The sinusoidal leading edge geometries included three amplitudes of 2.5%, 5%, and 12% and two wavelengths of 25% and 50% of the mean chord length. Results revealed that cavitation on the leading edge-modified hydrofoils existed in pockets behind the troughs whereas the baseline hydrofoil produced cavitation along its entire span. Moreover, cavitation on the modified hydrofoils appeared at consistently lower angles of attack than on the baseline hydrofoil.

  6. A benchmark experiment on gas cavitation

    Science.gov (United States)

    Peters, Franz; Honza, Rene

    2014-08-01

    Cavitation research is often a matter of experiments conducted in complex machinery. There, it is extremely difficult to look into one of the most important issues of cavitation which is nucleation. This work investigates gas cavitation under well-defined flow conditions. Nuclei are placed in wall bound cavities and are exposed to a radial gap flow featuring independent pressure and shear stress. A reciprocating bubble generation is achieved. Bubble frequency and size are evaluated which turn out to depend on pressure and wall shear stress. The experiment lends itself to systematic research in cavitation.

  7. A dynamic method based on the specific substrate uptake rate to set up a feeding strategy for Pichia pastoris

    National Research Council Canada - National Science Library

    Dietzsch, Christian; Spadiut, Oliver; Herwig, Christoph

    2011-01-01

    .... To date, strain specific parameters, which are needed to set up feeding profiles for fed batch cultivations, are determined by time-consuming continuous cultures or consecutive fed batch cultivations...

  8. Temperature measurements in cavitation bubbles

    Science.gov (United States)

    Coutier-Delgosha, Olivier

    2016-11-01

    Cavitation is usually a nearly isothermal process in the liquid phase, but in some specific flow conditions like hot water or cryogenic fluids, significant temperature variations are detected. In addition, a large temperature increase happens inside the cavitation bubbles at the very end of their collapse, due to the fast compression of the gas at the bubble core, which is almost adiabatic. This process is of primary interest in various biomedical and pharmaceutical applications, where the mechanisms of bubble collapse plays a major role. To investigate the amplitude and the spatial distribution of these temperature variations inside and outside the cavitation bubbles, a system based on cold wires has been developed. They have been tested in a configuration of a single bubble obtained by submitting a small air bubble to a large amplitude pressure wave. Some promising results have been obtained after the initial validation tests. This work is funded by the Office of Naval Research Global under Grant N62909-16-1-2116, Dr. Salahuddin Ahmed & Ki-Han Kim program managers.

  9. DESIGN NOTE: A control system for Langmuir-Blodgett film deposition set-up based on microstepping

    Science.gov (United States)

    Navathe, C. P.; Dashora, B. L.; Roy, U. N.; Singh, R.; Maheswari, S.; Kukreja, L. M.

    1998-03-01

    A control system for Langmuir-Blodgett (LB) film set-up has been developed based on the principle of microstepping of the stepper motors to drive the barriers and the substrate with precision and smooth motion. The stepper motors and the Wilhelmy plate used to measure the monolayer surface pressure are interfaced to a microcomputer for automatic operation. This home-made LB film set-up has been successfully used to fabricate LB films of cadmium arachidate of high crystalline quality.

  10. Set up of analytical methods for evaluation of specifications of recombinant Hepatitis-B vaccine

    Directory of Open Access Journals (Sweden)

    Daram M

    2009-06-01

    Full Text Available "nBackground: Hepatitis B vaccination has been included in routine immunization of all individuals according to WHO recommendations since 1991. Despite successful coverage, 3-5% of recipients fail to mount a desirable protection level of Ab. Vaccine failure results from: emergence of mutation, immune failure of individuals, decrease in vaccine potency, and etc. The quality of Hepatitis B vaccine should be evaluated by a reliable method. "n"nMethods: The amount of vaccine antigen was measured through the in vitro assay of Hepatitis B vaccines which consists of multiple dilutions of the reference material and samples. The preparations were evaluated by Elisa to determine the amount of HBsAg. The data were analyzed by parallel-line analysis software. The in vivo assay was performed by inoculating multiple doses of the reference and sample preparations in Balb/c mice. A control group was also inoculated with vaccine matrix. Four weeks later, the mice sera were evaluated to determine the presence of antibodies against Hepatitis B by Elisa method. The data were analyzed by Probit analysis software. "n"nResults: Both methods were set up in our laboratory by which different batches of Hepatitis B vaccine were evaluated. It was observed that In vivo and In vitro methods provide comparable results. Therefore we can use the in vitro method for routine testing of HB vaccine quality control. "n"nConclusion: In vitro method can be used in place of In vivo method because of its time and cost-effectiveness. Moreover, since no animals are used in in vitro method, it complies well with the 3R concept (Reduction, Refinement, and Replacement of animal testing and the current tendency to use alternative method.

  11. Analysis and Optimization of Nutritional Set-up for Murine Pancreatic Acinar Cells.

    Directory of Open Access Journals (Sweden)

    Kurup S

    2002-01-01

    Full Text Available CONTEXT: Pancreatic acinar cell cultivation poses a serious problem due to limitations in the in vitro survival time despite variations of dissociation protocols, culture media and nutrient supplements. OBJECTIVE: To establish a long term culture of murine pancreatic acinar cells which retain their viability, monolayer formation and responsiveness to secretagogues. In order to investigate the mechanism of the short-life of acinar cells studied in vitro, we studied their survival under the influence of different supplements on nutrient media. INTERVENTIONS: Dissociated pancreatic acini were prepared from BALB/c mice pancreata by collagenase digestion supplemented with bovine serum albumin fraction V and soybean trypsin inhibitor. A nutrient set-up was designed for their long term survival in vitro. RESULTS: It was observed that mouse pancreatic acinar cells dissociated in presence of bovine serum albumin fraction V and soybean trypsin inhibitor result in 95% viability. Further cultivation of these acinar cells in Waymouth's MB 752/1 medium supplemented with 10% fetal calf serum (v/v, soybean trypsin inhibitor, bovine serum albumin, dexamethasone, and epidermal growth factor results in their survival for more than 6 days in culture with 85% viability, retention of the secretagogue responsiveness and formation of a monolayer without any extracellular matrix coating. CONCLUSIONS: Our study clearly demonstrates that the addition of soybean trypsin inhibitor to culture medium reduces zymogen granule fragility and acinar cell death, thus increasing their viability for sufficiently long periods. The present study offers an excellent, in vitro model for the investigation of exocrine dysfunction in response to acinar cell injury.

  12. The importance of site selection for setting up a wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Raghunandan, A.; Gowda, G.; Pandian, A. [MS RAMAIAH Institute of Technology, Bangalore (India); Ramanan, G. [RV College of Engineering, Bangalore (India)

    2012-07-01

    A wind energy system transforms the kinetic energy of the wind into mechanical or electrical energy that can be harnessed for practical use. Building a wind turbine is far more than simply a matter of finding a field or mountaintop where the wind is blowing and plopping one down. A great deal of attention should be given to finding the proper site for a wind turbine. The main factor one should consider is the average speed of the wind over an extended time. Estimation of the wind power potential for a site is the most important requirement for selecting a site for the installation of a wind turbine. Also wind turbines should be sited well above trees, buildings, and other obstacles else, the result will be poor energy production and increased wear and tear on the turbine. One way to get rid of this is to place the wind turbine on a tall tower. When selecting a place for setting up a wind turbine, engineers consider factors such as wind hazards, characteristics of the land that affect wind speed, and the effects of one turbine on nearby turbines in wind farms. The other factors that are important for selecting a site for installation of wind turbines are Hill effect, Roughness, or the amount of friction that Earth's surface exerts on wind, Tunnel effect, Turbulence, Variations in wind speed, Wind obstacles and Wind shear. This paper will emphasis on the necessary inspections which are to be done on the site before installing a Wind Turbine. (Author)

  13. Cavitation Generated by Amplitude Modulated HIFU: Investigation on the Inertial Cavitation Threshold

    Science.gov (United States)

    Gilles, Bruno; Saletes, Izella; Béra, Jean-Christophe

    2007-05-01

    An experimental investigation on cavitation threshold was carried out in order to compare monochromatic and dichromatic ultrasound excitations in their ability to generate inertial cavitation on a target. Using a cavitation activity spectral criterion, a precise inertial cavitation threshold could be extracted in every case considered. The results showed that these thresholds could be very different depending on the type of excitation used. More precisely, for the parameters investigated in the present study, the ratio between monochromatic and dichromatic thresholds decreased when cavitation thresholds are increased. The potential application of this study to purely ultrasonic thrombolysis is discussed.

  14. Cavitation instabilities of an inducer in a cryogenic pump

    Science.gov (United States)

    Kim, Dae-Jin; Sung, Hyung Jin; Choi, Chang-Ho; Kim, Jin-Sun

    2017-03-01

    Inducers assist cryogenic pumps to operate safely under cavitation conditions by increasing the pressure of the impeller inlet, but create cavitation instabilities. The use of cryogenic fluids requires special attention because of safety and handling concerns. To examine the cavitation instabilities of a cryogenic pump, two kinds of working fluids, water and liquid oxygen, were employed. The cavitation instabilities were measured with an accelerometer installed on the pump casing. The flow coefficient and the head slightly decrease with decreases in the cavitation number before the cavitation breakdown. These trends are true of both fluids. Several cavitation instabilities were identified with the accelerometer. At lower flow coefficients, super-synchronous rotating cavitation was found in a similar cavitation number range for both fluids. At higher flow coefficients, the cavitation numbers of the cavitation instabilities in the liquid oxygen test are smaller than those of the water test.

  15. Influence of experimental set-up on the infiltration characteristics during managed aquifer recharge operation

    Science.gov (United States)

    Fichtner, Thomas; Vanzella de Melo, Julio Augusto; Stefan, Catalin

    2016-04-01

    The main focus during operation of managed aquifer recharge (MAR) is on clogging processes, specifically on the changes of infiltration capacities and degradation of infiltrated organic substances including vadose zone oxygen dynamics. Lab scale experiments are one opportunity to understand and characterize these processes under different drying and wetting cycles and infiltration rates. However, the multitude of assumptions and scale-related limitations of downscale investigations often lead to over- or underestimations, rendering their results useless when translated to field-like conditions. Therefore, the specific objective of this investigation is to compare the results obtained from two different experimental set-ups with different scales: a 3D, rectangular shaped, stainless steel lysimeter (1.5 x 1.0 x 1.0 m) with an infiltration basin installed in the centre of its surface and a 1D soil column (1m, ᴓ 0.15 m) with the infiltration over the complete column surface. The study focuses on the influence of the experimental setup conditions on the soil clogging, water flow pattern, oxygen dynamics and degradation of organic substances. The results should allow making statements about the suitability of these lab experiments for the investigation of processes taking place in the unsaturated soil zone during operation of MAR. Both experimental units were packed with the same soil and equipped with tensiometers, TDR-probes, oxygen probes and suction cups in two depths for the estimation of spatial and temporal distribution of soil moisture, oxygen and infiltrated substances. The lysimeter and the column were placed inside of a fully automatic climate tent, which facilitates the exact control of air temperature and humidity. The first results confirm that both infiltration units are suitable to simulate the clogging and the oxidation of easily degradable organic substances. However, the velocity of water transport is higher in the column compared with the lysimeter

  16. Set-up and validation of a Delft-FEWS based coastal hazard forecasting system

    Science.gov (United States)

    Valchev, Nikolay; Eftimova, Petya; Andreeva, Nataliya

    2017-04-01

    European coasts are increasingly threatened by hazards related to low-probability and high-impact hydro-meteorological events. Uncertainties in hazard prediction and capabilities to cope with their impact lie in both future storm pattern and increasing coastal development. Therefore, adaptation to future conditions requires a re-evaluation of coastal disaster risk reduction (DRR) strategies and introduction of a more efficient mix of prevention, mitigation and preparedness measures. The latter presumes that development of tools, which can manage the complex process of merging data and models and generate products on the current and expected hydro-and morpho-dynamic states of the coasts, such as forecasting system of flooding and erosion hazards at vulnerable coastal locations (hotspots), is of vital importance. Output of such system can be of an utmost value for coastal stakeholders and the entire coastal community. In response to these challenges, Delft-FEWS provides a state-of-the-art framework for implementation of such system with vast capabilities to trigger the early warning process. In addition, this framework is highly customizable to the specific requirements of any individual coastal hotspot. Since its release many Delft-FEWS based forecasting system related to inland flooding have been developed. However, limited number of coastal applications was implemented. In this paper, a set-up of Delft-FEWS based forecasting system for Varna Bay (Bulgaria) and a coastal hotspot, which includes a sandy beach and port infrastructure, is presented. It is implemented in the frame of RISC-KIT project (Resilience-Increasing Strategies for Coasts - toolKIT). The system output generated in hindcast mode is validated with available observations of surge levels, wave and morphodynamic parameters for a sequence of three short-duration and relatively weak storm events occurred during February 4-12, 2015. Generally, the models' performance is considered as very good and

  17. The experience of a nationwide Community of Practice to set up Regional Prevention Plans in Italy.

    Science.gov (United States)

    Giusti, Angela; Perra, Alberto; Lombardo, Flavia

    2017-07-27

    In 2010, the Italian Ministry of Health decided to start the planning process to elaborate the National Plan of Prevention 2010-2012 jointly with the 21 Regions. The National Institute of Health was responsible for supporting regional planners (RPs) by an original participatory approach of a web-based Community of Practice (CoP) to set up their own Regional Plans of Prevention. In this paper, we summarise the theoretical framework adopted, the main phases characterising the lifecycle of the nationwide CoP, the evaluation approach adopted and its findings. Following the CoP theoretical framework from Wenger, an initial group of RPs were trained on Project Cycle Management as a planning method and thereafter they started interacting on a web-based Moodle platform for 8 months. The CoP evaluation mainly took into account aspects of 'immediate value', such as members interactions within the website, and several quantitative and qualitative tools were used to monitor changes over time. Data were retrieved from Moodle statistics or directly from the RPs by the means of a Knowledge, Attitude and Practice survey, a reaction survey, SWOT analysis and focus groups. The level of individual RPs knowledge increased after the initial course from 55.7% to 75%, attitudes and competence perception about the planning process method also showed an overall favourable change. During the CoP life span, the number of members increased from the original 98 RPs to include up to 600 new members on the basis of spontaneous demand. From April 2010 to January 2011, the 'vital signs' of the CoP were monitored, including RP logins (13,450 total logins and 3744 unique logins), views (27,522) and posts (1606) distributed in 326 forum discussion threads. Data and information retrieved from quantitative and qualitative evaluation approaches proved to be useful for the management and follow-up of the CoP. The CoP experience was successful as 19 out of 20 Regions submitted their Regional Preventive

  18. Cavitation dispersion of carbon nanotubes and modification of cement systems

    Directory of Open Access Journals (Sweden)

    GUSEV Boris Vladimirovich

    2014-12-01

    Full Text Available The most common research areas in construction material science deals with the development of new efficient methods to increase strength properties of materials. One of such methods is modification of composite matrices with carbon nanotubes. The characteristics of nanomodified concretes to a great extent depend on selected method of introduction of carbon nanotubes into material. The predispersion of CNT in mixing water with plasticizing additive through ultrasound impact on the environment with colloid and other types of particles including nanoparticles is the most frequently used scientific method which provides even distribution of nanoparticles in cement. In some works the separation of agglomerated CNT in suspension was conducted by means of ultrasound treatment. The further analysis showed that the main drawbacks of ultrasound dispersion are high energy output and low performance. That causes inconvenience for application of them in manufacturing process. The methods of cavitation dispersion which were developed in the late 90ies in the XXI century today are becoming commonly used in practice. The work presents the results of dispersion of multi-layer nanotubes performed on the hydrodynamic cavitation equipment. It was determined that the use of such equipment makes it possible to produce stable and even carbon dispersions and to introduce and distribute them uniformly in concrete in the same way as in the case when ultrasound treatment is performed. The advantages of this technology are considerable decrease of energy consumption and possibility to treat enormous amounts of liquids which are necessary for modification of concrete in real production process.

  19. Interaction of cavitation bubbles on a wall

    NARCIS (Netherlands)

    Bremond, Nicolas; Arora, Manish; Dammer, Stephan M.; Lohse, Detlef

    2006-01-01

    We report experimental and numerical investigations on the dynamics of the cavitation of bubbles on a solid surface and the interaction between them with the help of controlled cavitation nuclei: hemispherical bubbles are nucleated from hydrophobic microcavities that act as gas traps when the substr

  20. MICRO-COURSE OF CAVITATION EROSION

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhaoyun

    2008-01-01

    By cavitation tests and scanning electron microscope (SEM) microanalysis, the micro- appearance of cavitation samples is studied. It is the first time that the micro-appearance of metals is pursued successfully. According to the changing course of the micro-appearance of metals, the damaging course of cavitation erosion is determined. The destructive way of collapsing bubbles on the metal surface is known. Firstly cavitation pinholes appear on the metal surface, then cracks generate and grow under the action of collapsing bubbles. When cracks connect each other, small pieces are removed from pinhole wall and pinholes develop into cavitation pits. When the previous surface is removed completely, new pinholes are produced again on the new surface. A pinhole is the result of the powerful striking of a micro-liquid jet ejected by a large collapsed bubble near the surface. At some stages, cracks grow in the way of fatigue. The corrosion phenomenon is observed during the cavitation erosion. The cavitation pattern can be used to explain the cavitation pregnancy and the changing regulation of sample surface.

  1. CALIBRATED HYDRODYNAMIC MODEL

    Directory of Open Access Journals (Sweden)

    Sezar Gülbaz

    2015-01-01

    Full Text Available The land development and increase in urbanization in a watershed affect water quantityand water quality. On one hand, urbanization provokes the adjustment of geomorphicstructure of the streams, ultimately raises peak flow rate which causes flood; on theother hand, it diminishes water quality which results in an increase in Total SuspendedSolid (TSS. Consequently, sediment accumulation in downstream of urban areas isobserved which is not preferred for longer life of dams. In order to overcome thesediment accumulation problem in dams, the amount of TSS in streams and inwatersheds should be taken under control. Low Impact Development (LID is a BestManagement Practice (BMP which may be used for this purpose. It is a land planningand engineering design method which is applied in managing storm water runoff inorder to reduce flooding as well as simultaneously improve water quality. LID includestechniques to predict suspended solid loads in surface runoff generated over imperviousurban surfaces. In this study, the impact of LID-BMPs on surface runoff and TSS isinvestigated by employing a calibrated hydrodynamic model for Sazlidere Watershedwhich is located in Istanbul, Turkey. For this purpose, a calibrated hydrodynamicmodel was developed by using Environmental Protection Agency Storm WaterManagement Model (EPA SWMM. For model calibration and validation, we set up arain gauge and a flow meter into the field and obtain rainfall and flow rate data. Andthen, we select several LID types such as retention basins, vegetative swales andpermeable pavement and we obtain their influence on peak flow rate and pollutantbuildup and washoff for TSS. Consequently, we observe the possible effects ofLID on surface runoff and TSS in Sazlidere Watershed.

  2. Comparison of Different Mathematical Models of Cavitation

    Directory of Open Access Journals (Sweden)

    Dorota HOMA

    2014-12-01

    Full Text Available Cavitation occurs during the flow when local pressure drops to the saturation pressure according to the temperature of the flow. It includes both evaporation and condensation of the vapor bubbles, which occur alternately with high frequency. Cavitation can be very dangerous, especially for pumps, because it leads to break of flow continuity, noise, vibration, erosion of blades and change in pump’s characteristics. Therefore it is very important for pump designers and users to avoid working in cavitation conditions. Simulation of flow can be very useful in that and can indicate if there is risk of cavitating flow occurrence. As this is a multiphase flow and quite complicated phenomena, there are a few mathematical models describing it. The aim of this paper is to make a short review of them and describe their approach to model cavitation. It is desirable to know differences between them to model this phenomenon properly.

  3. Reflections on cavitation nuclei in water

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2007-01-01

    The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...... pressure, the possibility of stabilization of free gas bubbles by a skin has been documented, but only within a range of bubble sizes that makes them responsible for tensile strengths up to about 1.5 bar, and values reaching almost 300 bar have been measured. However, cavitation nuclei can also be harbored...

  4. Cavitation occurrence around ultrasonic dental scalers.

    Science.gov (United States)

    Felver, Bernhard; King, David C; Lea, Simon C; Price, Gareth J; Damien Walmsley, A

    2009-06-01

    Ultrasonic scalers are used in dentistry to remove calculus and other contaminants from teeth. One mechanism which may assist in the cleaning is cavitation generated in cooling water around the scaler. The vibratory motion of three designs of scaler tip in a water bath has been characterised by laser vibrometry, and compared with the spatial distribution of cavitation around the scaler tips observed using sonochemiluminescence from a luminol solution. The type of cavitation was confirmed by acoustic emission analysed by a 'Cavimeter' supplied by NPL. A node/antinode vibration pattern was observed, with the maximum displacement of each type of tip occurring at the free end. High levels of cavitation activity occurred in areas surrounding the vibration antinodes, although minimal levels were observed at the free end of the tip. There was also good correlation between vibration amplitude and sonochemiluminescence at other points along the scaler tip. 'Cavimeter' analysis correlated well with luminol observations, suggesting the presence of primarily transient cavitation.

  5. Evaluating Speed Enforcement Field Set-Ups Used by Regional Police in Belgium: An Analysis of Speed Outcome Indicators

    Directory of Open Access Journals (Sweden)

    Brenda Wilmots

    2016-12-01

    Full Text Available In this paper the results from a field experiment (conducted in 2012 are presented, in which 3 regional police units in the Flemish region of Belgium each tested a particular combination of a speed control (with mobile radar in an anonymous car with communicative signage. The goal of this paper was to scientifically evaluate frequently used field set-ups. The following set-ups were tested in one week: (1 police unit 1: speed control with and without a static feedback sign placed after the control; (2 police unit 2: speed control with and without a digital feedback sign placed after the control; (3 police unit 3: speed display followed by a second speed display further along the road section. During certain time frames, speed control took place in between both signs. All tested field set-ups generated significant reductions in the speed level. Studying the effect of the different variations for each set-up reveals that the effect of the speed control is generally larger in combination with the signage alongside the road. After the period during which the police activities took place, speed levels again reached their initial level. Based on the before–after analysis, only in police area 2 was a small ‘time halo-effect’ found. To generalize results from this pilot study, repetition of tested set-ups in the field is recommended as well as testing on a larger scale.

  6. Steady State Thermo-Hydrodynamic Analysis of Two-Axial groove and Multilobe Hydrodynamic Bearings

    Directory of Open Access Journals (Sweden)

    C. Bhagat

    2014-12-01

    Full Text Available Steady state thermo-hydrodynamic analysis of two axial groove and multi lobe oil journal bearings is performed in this paper. To study the steady state thermo-hydrodynamic characteristics Reynolds equation is solved simultaneously along with the energy equation and heat conduction equation in bush and shaft. The effect of groove geometry, cavitation in the fluid film, the recirculation of lubricant, shaft speed has also been taken into account. Film temperature in case of three-lobe bearing is found to be high as compared to other studied bearing configurations. The data obtained from this analysis can be used conveniently in the design of such bearings, which are presented in dimensionless form.

  7. Lubrication and thermal characteristics of mechanical seal with porous surface based on cavitation

    Science.gov (United States)

    Huilong, Chen; Muzi, Zuo; Tong, Liu; Yu, Wang; Cheng, Xu; Qiangbo, Wu

    2014-04-01

    The theory model of mechanical seals with laser-textured porous surface (LST-MS) was established. The liquid film of LST-MS was simulated by the Fluent software, using full cavitation model and non-cavitation model separately. Dynamic mesh technique and relationship between viscosity and temperature were applied to simulate the internal flow field and heat characteristics of LST-MS, based on the more accurate cavitation model. Influence of porous depth ratio porous diameter ɛ and porous density SP on lubrication performance and the variation of lubrication and thermal properties with shaft speed and sealing pressure were analyzed. The results indicate that the strongest hydrodynamic pressure effect and the biggest thickness of liquid film are obtained when ɛ and SP are respectively about 0.025 and 0.5 which were thought to be the optimum value. The frictional heat leads to the increase of liquid film temperature and the decrease of medium viscosity with the shaft speed increasing. The hydrodynamic pressure effect increases as shaft speed increasing, however it decreases as the impact of frictional heat.

  8. SOME REMARKS ON HYDROFOIL CAVITATION

    Institute of Scientific and Technical Information of China (English)

    ARNDT Roger E.A.

    2012-01-01

    This paper reviews numerical and experimental investigations of sheet/cloud cavitation carried out at the St.Anthony Falls Laboratory and at two collaborating facilities (Versuchsanstalt Für Wasserbau,Obernach,Germany and Osaka University,Japan) for more than a decade.Although significant advances have been made in the analysis of this flow several issues are still unresolved.The purpose of this paper is to examine the overall features of the problem,review the progress made to date and suggest avenues for new investigation.

  9. Enterobacter Asburiae Pneumonia with Cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Seung Woo; Heo, Jeong Nam; Park, Choong Ki [Dept. of Radiology, Hanyang University College of Medicine, Guri Hospital, Guri (Korea, Republic of); Choi, Yo Won; Jeon, Seok Chol [Dept. of Radiology, Hanyang University College of Medicine, Seoul Hospital, Seoul (Korea, Republic of)

    2013-03-15

    Enterobacter species have increasingly been identified as pathogens over the past several decades. These bacterial species have become more important because most are resistant to cephalothin and cefoxitin, and can produce extended-spectrum {beta}-lactamase. Enterobacter asburiae (E. asburiae) is a gram-negative rod of the family Enterobacteriaceae, named in 1986. Since then, there has been only one clinical report of E. asburiae pneumonia. We report a case of E. asburiae pneumonia with cavitation and compare it with the previous case.

  10. A Full-size High Temperature Superconducting Coil Employed in a Wind Turbine Generator Set-up

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Kellers, Jürgen

    2016-01-01

    is tested in LN2 first, and then tested in the set-up so that the magnetic environment in a real generator is reflected. The experimental results are reported, followed by a finite element simulation and a discussion on the deviation of the results. The tested and estimated Ic in LN2 are 148 A and 143 A......A full-size stationary experimental set-up, which is a pole pair segment of a 2 MW high temperature superconducting (HTS) wind turbine generator, has been built and tested under the HTS-GEN project in Denmark. The performance of the HTS coil is crucial to the set-up, and further to the development...

  11. A conceptual design of the set-up for solid state spectroscopy with free electron laser and insertion device radiation

    CERN Document Server

    Makhov, V N

    2001-01-01

    The set-up for complex solid state spectroscopy with the use of enhanced properties of radiation from insertion devices and free electron lasers is proposed. Very high flux and pulsed properties of radiation from insertion devices and free electron lasers offer the possibility for the use of such powerful techniques as electron paramagnetic resonance (EPR) and optically detected magnetic resonance (ODMR) for the studies of excited states of electronic excitations or defects in solids. The power density of radiation can become high enough for one more method of exited-state spectroscopy: transient optical absorption spectroscopy. The set-up is supposed to combine the EPR/ODMR spectrometer, i.e. cryostat supplied with superconducting magnet and microwave system, and the optical channels for excitation (by radiation from insertion devices or free electron laser) and detection of luminescence (i.e. primary and secondary monochromators). The set-up can be used both for 'conventional' spectroscopy of solids (reflec...

  12. Study on cavitation characteristics of horizontal axis tidal turbine%水平轴潮流能水轮机空化特性研究

    Institute of Scientific and Technical Information of China (English)

    张亮; 房良; 张学伟

    2015-01-01

    采用C FD (计算流体力学)数值模拟的方法,对水平轴潮流能水轮机的空化特性进行研究。重点讨论叶片空化的特性和对水轮机水动力性能的影响,得出不同空化数下叶片空化程度和位置及对水动力性能的损耗。在相同空化数下,分别研究来流速度及叶轮旋转角速度对叶片空化情况的影响,得出不同工况下叶片的空化区域,针对空化区域的不同研究水动力性能的降低程度。结果表明:叶片的空化程度及区域不仅和空化数有关,还受到叶尖速比的影响;空化的发生并不一定会严重影响水轮机的水动力性能,空化对水动力性能的影响关键在于空化发生的区域,只有当空化数低于一定数值,叶片中段发生空化时,才会大幅影响水动力性能。%T he cavitation characteristics of horizontal axis tidal turbine w as studied by using CFD (computational fluid dynamics)numerical simulation method .The cavitation characteristics of blade and the effect of hydrodynamic performance were focused on ,the extent and location of cavitation on the blade in different cavitation number ,and the loss of the hydrodynamic performance was obtained meanwhile .At the same cavitation number ,the impact of the flow velocity and the angular velocity of rotation were studied ,the region of cavitation on the blade in different situation was obtained ,and then the reduction of hydrodynamic performances of the turbine were studied at the different region of cavitation .The results show that the extent and region of cavitation is not only associated with the cavitation number ,but also affected by the tip speed ratio ;the occurrence of cavitation will not neces‐sarily affect the hydrodynamic performance of the turbine ,the key of the influence of the cavitation on the hydrodynamic performance is the area of cavitation ,which would greatly affect on the hydrody‐namic performance only when the

  13. Test of a cryogenic set-up for a 10 meter long liquid nitrogen cooled superconducting power cable

    DEFF Research Database (Denmark)

    Træholt, Chresten; Rasmussen, Carsten; Kühle (fratrådt), Anders Van Der Aa;

    2000-01-01

    High temperature superconducting power cables may be cooled by a forced flow of sub-cooled liquid nitrogen. One way to do this is to circulate the liquid nitrogen (LN2) by means of a mechanical pump through the core of the cable and through a sub-cooler.Besides the cooling station, the cryogenics...... cable. We report on our experimental set-up for testing a 10 meter long high temperature superconducting cable with a critical current of 3.2 kA at 77K. The set-up consists of a custom designed cable end termination, current lead, coolant feed-through, liquid nitrogen closed loop circulation system...

  14. Test of experimental set-ups for electrodialytic removal of Cu, Zn, Pb and Cd from different contaminated harbour sediments

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    of the sediment slurry, the other without stirring. The removal of heavy metals was highest in the non-calcareous sediment, where 94% Cd, 91% Zn and 73% Cu were removed after 24 days. The highest removal obtained for the calcareous sediment was 81% Cd, 76% Zn, 75% Pb and 53% Cu after 21 days, with stirred...... was the most stable in these experiments, and thus, the stirred set-up is the best choice for experimental set-up. The order in which the heavy metals were removed from the harbour sediments was Cd>Zn>Pb>Cu....

  15. The possibility to use `energy plus transmutation' set-up for neutron production and transport benchmark studies

    Indian Academy of Sciences (India)

    V Wagner; A Krása; M Majerla; F Křížek; O Svoboda; A Kugler; J Adam; V M Tsoupko-Sitnikov; M I Krivopustov; I V Zhuk; W Westmeier

    2007-02-01

    The set-up `energy plus transmutation', consisting of a thick lead target and a natural uranium blanket, was irradiated by relativistic proton beams with the energy from 0.7 GeV up to 2 GeV. Neutron field was measured in different places of this set-up using different activation detectors. The possibilities of using the obtained data for benchmark studies are analyzed in this paper. Uncertainties of experimental data are shown and discussed. The experimental data are compared with results of simulation with MCNPX code.

  16. Evaluation of errors set-up and setting margins calculation in treatments 3-D conformal radiotherapy; Evaluacion de errores de set-up y calculo de margenes de configuracion en tratamientos de radioterapia CONFORMADA 3-D

    Energy Technology Data Exchange (ETDEWEB)

    Donis, S.; Robayna, B.; Gonzalez, A.; Hernandez Armas, J.

    2011-07-01

    The use of IGRT techniques provide knowledge of the mistakes made in the positioning of a patient, to population studies and estimate the margins for each population.In this paper we evaluate the errors of set-up in 3 different locations and from these margins are calculated configuration (SM).

  17. Simulations of Cavitating Cryogenic Inducers

    Science.gov (United States)

    Dorney, Dan (Technical Monitor); Hosangadi, Ashvin; Ahuja, Vineet; Ungewitter, Ronald J.

    2004-01-01

    Simulations of cavitating turbopump inducers at their design flow rate are presented. Results over a broad range of Nss, numbers extending from single-phase flow conditions through the critical head break down point are discussed. The flow characteristics and performance of a subscale geometry designed for water testing are compared with the fullscale configuration that employs LOX. In particular, thermal depression effects arising from cavitation in cryogenic fluids are identified and their impact on the suction performance of the inducer quantified. The simulations have been performed using the CRUNCH CFD[R] code that has a generalized multi-element unstructured framework suitable for turbomachinery applications. An advanced multi-phase formulation for cryogenic fluids that models temperature depression and real fluid property variations is employed. The formulation has been extensively validated for both liquid nitrogen and liquid hydrogen by simulating the experiments of Hord on hydrofoils; excellent estimates of the leading edge temperature and pressure depression were obtained while the comparisons in the cavity closure region were reasonable.

  18. Simulation and Experimental Study on Cavitating Water Jet Nozzle

    Science.gov (United States)

    Zhou, Wei; He, Kai; Cai, Jiannan; Hu, Shaojie; Li, Jiuhua; Du, Ruxu

    2017-01-01

    Cavitating water jet technology is a new kind of water jet technology with many advantages, such as energy-saving, efficient, environmentally-friendly and so on. Based on the numerical simulation and experimental verification in this paper, the research on cavitating nozzle has been carried out, which includes comparison of the cleaning ability of the cavitating jet and the ordinary jet, and comparison of cavitation effects of different structures of cavitating nozzles.

  19. Numerical simulation of multiphase cavitating flows around an underwater projectile

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The present simulation investigates the multiphase cavitating flow around an underwater projectile.Based on the Homogeneous Equilibrium Flow assumption,a mixture model is applied to simulate the multiphase cavitating flow including ventilated cavitation caused by air injection as well as natural cavitation that forms in a region where the pressure of liquid falls below its vapor pressure. The transport equation cavitating model is applied.The calculations are executed based on a suite of CFD code.The hyd...

  20. Minimum standard guidelines of care on requirements for setting up a laser room

    Directory of Open Access Journals (Sweden)

    Dhepe Niteen

    2009-08-01

    Full Text Available Introduction, definition, rationale and scope: Lasers are now becoming an integral part of dermatological practice in India, with more and more dermatologists starting laser dermatology practice. Lasers, when are used with care, by properly trained operators, in carefully designed environment, can deliver a range of useful aesthetic and dermatologic treatments. Facility: Laser treatment is an office procedure, hence it does not require hospital set-up. The laser room facility requires careful planning keeping in mind safety of both patient and operator, convenience of operating, and optimum handling of costly equipments. The facility should be designed to handle procedures under local anesthesia and sedation. Facilities, staff and equipment to handle any emergencies should be available. Location: A room in existing dermatology clinic can be adequately converted to a laser room. Dimensions of laser room, its door and patient′s table should be such that it should facilitate easy movement of patient, machine trolley, operator and assistant in case of routine procedures and in emergency. Physician Qualification: Any dermatologist with MD or diploma in dermatology can do laser procedures, provided he/ she has acquired necessary skills by virtue of training, observing a competent dermatologist. Such training may be obtained during post graduation or later in specified workshops or courses under a competent dermatologist or at centre which routinely performs such procedures. Electricity and uninterrupted power supply: Laser equipments should be connected to stabilizer or UPS circuits only. Preferably an on line UPS as recommended by the laser company should be installed. Earthing of the equipment is essential to avoid damage to the equipment and electrical shocks to the operator. Sufficient power back up to complete the procedure if power is off midway, is essential. Air-conditioning: Laser machines should be operated in low ambient temperature, with

  1. 水力空化水处理设备的控制系统设计%The Design of Control System for Hydrodynmic Cavitation Water Treatment Equipment

    Institute of Scientific and Technical Information of China (English)

    刘志猛; 陈平; 邓橙; 苑英海; 朱孟府

    2012-01-01

    为了完成对水力空化水处理设备的自动控制,结合水力空化水处理技术工艺,应用PLC控制器和触摸屏技术,开发并设计一套水力空化水处理设备的控制系统.采用触摸屏作为人机界面,可实现pH、ORP、电导率、DO等水质参数实时检测、设定和修改等功能,并能方便直观地对水力空化水处理设备的工作过程进行监控.经过实际运行和调试,基于PLC和触摸屏的水力空化水处理设备的控制系统稳定性好、可靠性高、易于维护,提高了水力空化水处理设备的效率和自动化水平.%In order to complete automatic control of the hydrodynamic cavitation water treatment equipment, by adopting PLC and touch screen technologies, a control system of the hydrodynamic cavitation water treatment equipment is designed and developed it is based on technological process of the hydrodynamic cavitation water treatment. The system equips with touch screen as the human machine interface implementes the functions of real-time detection, parameter setting and modification of the water quality parameters such as pH, ORP, TDS and DO. Thus the operating process of the hydrodynamic cavitation water treatment equipment can be easily and directly perceived and controlled. The control system of the hydrodynamic cavitation water treatment equipment has good stability and reliability, and is easy to maintenance for enhancing operation efficiency and automation level after practically working and debugging.

  2. Cavitation passive control on immersed bodies

    Science.gov (United States)

    Javadi, Khodayar; Dorostkar, Mohammad Mortezazadeh; Katal, Ali

    2017-03-01

    This paper introduces a new idea of controlling cavitation around a hydrofoil through a passive cavitation controller called artificial cavitation bubble generator (ACG). Cyclic processes, namely, growth and implosion of bubbles around an immersed body, are the main reasons for the destruction and erosion of the said body. This paper aims to create a condition in which the cavitation bubbles reach a steady-state situation and prevent the occurrence of the cyclic processes. For this purpose, the ACG is placed on the surface of an immersed body, in particular, the suction surface of a 2D hydrofoil. A simulation was performed with an implicit finite volume scheme based on a SIMPLE algorithm associated with the multiphase and cavitation model. The modified k-ɛ RNG turbulence model equipped with a modification of the turbulent viscosity was applied to overcome the turbulence closure problem. Numerical simulation of water flow over the hydrofoil equipped with the ACG shows that a low-pressure recirculation area is produced behind the ACG and artificially generates stationary cavitation bubbles. The location, shape, and size of this ACG are the crucial parameters in creating a proper control. Results show that the cavitation bubble is controlled well with a well-designed ACG.

  3. Cavitation passive control on immersed bodies

    Science.gov (United States)

    Javadi, Khodayar; Dorostkar, Mohammad Mortezazadeh; Katal, Ali

    2017-01-01

    This paper introduces a new idea of controlling cavitation around a hydrofoil through a passive cavitation controller called artificial cavitation bubble generator (ACG). Cyclic processes, namely, growth and implosion of bubbles around an immersed body, are the main reasons for the destruction and erosion of the said body. This paper aims to create a condition in which the cavitation bubbles reach a steady-state situation and prevent the occurrence of the cyclic processes. For this purpose, the ACG is placed on the surface of an immersed body, in particular, the suction surface of a 2D hydrofoil. A simulation was performed with an implicit finite volume scheme based on a SIMPLE algorithm associated with the multiphase and cavitation model. The modified k-ɛ RNG turbulence model equipped with a modification of the turbulent viscosity was applied to overcome the turbulence closure problem. Numerical simulation of water flow over the hydrofoil equipped with the ACG shows that a low-pressure recirculation area is produced behind the ACG and artificially generates stationary cavitation bubbles. The location, shape, and size of this ACG are the crucial parameters in creating a proper control. Results show that the cavitation bubble is controlled well with a well-designed ACG.

  4. Numerical simulation of 3-D incompressible, multi-phase flows over cavitating projectiles

    Energy Technology Data Exchange (ETDEWEB)

    Owis, F.M.; Nayfeh, A.H. [Blacksburg State University, Dept. of Engineering Science and Mechanics, MC 0219, Virginia Polytechnic Institute, VA (United States)

    2004-04-01

    The hydrodynamic cavitation over axisymmetric projectiles is computed using the unsteady incompressible Navier-Stokes equations for multi-fluid elements. The governing equations are discretized on a structured grid using an upwind difference scheme with flux limits. A preconditioning dual-time stepping method is used for the unsteady computations. The Eigen-system is derived for the Jacobian matrices. This Eigen-system is suitable for high-density ratio multi-fluid flows and it provides high numerical stability and fast convergence. This method can be used to compute single- as well as multi-phase flows. Cavitating flows over projectiles with different geometries are computed and the results are in good agreement with available experimental data and other published computations. (authors)

  5. Clinical Profile of Children and Adolescents Attending the Behavioural Paediatrics Unit OPD in a Tertiary Care Set up

    Science.gov (United States)

    Jayaprakash, R.

    2012-01-01

    Background: There are limited studies on the clinical profile of children attending child guidance clinic under Paediatric background. Aims: To study clinical profile of Children & adolescents attending the Behavioural Paediatrics Unit (BPU) OPD under department of Paediatrics in a tertiary care set up. Methods: Monthly average turnover in the…

  6. The Keithley System 570 Data Acquisition Workstation: A tool for setting up control and data acquisition in psychophysiological experiments.

    NARCIS (Netherlands)

    Wijker, W.; van der Molen, M.W.; Molenaar, P.C.M.; Maarsse, F.J.; Mulder, L.J.M.

    1991-01-01

    Discusses an experimental psychophysiological set-up using the Keithley System 570 Data Acquisition Workstation. Keithley System consists of hardware and software components which are capable of dealing with most of the demands required in experimental psychology. Reviews the hardware and software o

  7. Setting up a Low-Cost Lab Management System for a Multi-Purpose Computing Laboratory Using Virtualisation Technology

    Science.gov (United States)

    Mok, Heng Ngee; Lee, Yeow Leong; Tan, Wee Kiat

    2012-01-01

    This paper describes how a generic computer laboratory equipped with 52 workstations is set up for teaching IT-related courses and other general purpose usage. The authors have successfully constructed a lab management system based on decentralised, client-side software virtualisation technology using Linux and free software tools from VMware that…

  8. The development of a CPX measurement set-up capable of measuring tire-road noise effectively

    NARCIS (Netherlands)

    Bekke, D.A.

    2009-01-01

    In the Directive 2001/43 limits are put on the maximum noise level of a pass-by noise measurement on an ISO 10844 surface. This prescribed measurement set-up only gives an LAmax level of the total passage of a whole vehicle equipped with four tires and does not provide enough information for a probl

  9. A Mathematical Programming Model for Tactical Planning with Set-up Continuity in a Two-stage Ceramic Firm

    Directory of Open Access Journals (Sweden)

    David Pérez Perales

    2016-07-01

    Full Text Available It is known that capacity issues in tactical production plans in a hierarchical context are relevant since its inaccurate determination may lead to unrealistic or simply non-feasible plans at the operational level. Semi-continuous industrial processes, such as ceramic ones, often imply large setups and their consideration is crucial for accurate capacity estimation. However, in most of production planning models developed in a hierarchical context at this tactical (aggregated level, setup changes are not explicitly considered. Their consideration includes not only decisions about lot sizing of production, but also allocation, known as Capacitated Lot Sizing and Loading Problem (CLSLP. However, CLSLP does not account for set-up continuity, specially important in contexts with lengthy and costly set-ups and where product families minimum run length are similar to planning periods. In this work, a mixed integer linear programming (MILP model for a two stage ceramic firm which accounts for lot sizing and loading decisions including minimum lot-sizes and set-up continuity between two consecutive periods is proposed. Set-up continuity inclusion is modelled just considering which product families are produced at the beginning and at the end of each period of time, and not the complete sequence. The model is solved over a simplified two-stage real-case within a Spanish ceramic firm. Obtained results confirm its validity.

  10. Test of experimental set-ups for electrodialytic removal of Cu, Zn, Pb and Cd from different contaminated harbour sediments

    DEFF Research Database (Denmark)

    Nystrøm, Gunvor Marie; Ottosen, Lisbeth M.; Villumsen, Arne

    2005-01-01

    Electrodialytic removal of heavy metals from different harbour sediments was investigated. Electrodialytic remediation experiments in laboratory scale were made with calcareous and non-calcareous harbour sediments. Two different experimental set-ups were used for the study, one with stirring of t...

  11. A cavitation aggressiveness index within the Reynolds averaged Navier Stokes methodology for cavitating flows

    Institute of Scientific and Technical Information of China (English)

    KOUKOUVINIS P.; BERGELES G.; GAVAISES M

    2015-01-01

    The paper proposes a methodology within the Reynolds averaged Navier Stokes (RANS) solvers for cavitating flows capable of predicting the flow regions of bubble collapse and the potential aggressiveness to material damage. An aggressiveness index is introduced, called cavitation aggressiveness index (CAI) based on the total derivative of pressure which identifies surface areas exposed to bubble collapses, the index is tested in two known cases documented in the open literature and seems to identify regions of potential cavitation damage.

  12. Cavitation studies on axi-symmetric underwater body with pumpjet propulsor in cavitation tunnel

    Directory of Open Access Journals (Sweden)

    Ch. Suryanarayana

    2010-12-01

    Full Text Available A pumpjet propulsor (PJP was designed for an underwater body (UWB with axi-symmetric configuration. Its performance was predicted through CFD study and models were manufactured. The propulsor design was evaluated for its propulsion characteristics through model tests conducted in a Wind Tunnel (WT. In the concluding part of the study, evaluation of the cavitation performance of the pumpjet was undertaken in a cavitation tunnel (CT. In order to assess the cavitation free operation speeds and depths of the body, cavitation tests of the PJP were carried out in behind condition to determine the inception cavitation numbers for rotor, stator and cowl. The model test results obtained were corrected for full scale Reynolds number and subsequently analyzed for cavitation inception speeds at different operating depths. From model tests it was also found that the cavitation inception of the rotor takes place on the tip face side at higher advance ratios and cavitation shifts towards the suction side as the RPS increases whereas the stator and cowl are free from cavitation.

  13. Cell mechanics in biomedical cavitation

    Science.gov (United States)

    Wang, Qianxi; Manmi, Kawa; Liu, Kuo-Kang

    2015-01-01

    Studies on the deformation behaviours of cellular entities, such as coated microbubbles and liposomes subject to a cavitation flow, become increasingly important for the advancement of ultrasonic imaging and drug delivery. Numerical simulations for bubble dynamics of ultrasound contrast agents based on the boundary integral method are presented in this work. The effects of the encapsulating shell are estimated by adapting Hoff's model used for thin-shell contrast agents. The viscosity effects are estimated by including the normal viscous stress in the boundary condition. In parallel, mechanical models of cell membranes and liposomes as well as state-of-the-art techniques for quantitative measurement of viscoelasticity for a single cell or coated microbubbles are reviewed. The future developments regarding modelling and measurement of the material properties of the cellular entities for cutting-edge biomedical applications are also discussed. PMID:26442142

  14. Reflections on cavitation nuclei in water

    DEFF Research Database (Denmark)

    Mørch, Knud Aage

    2007-01-01

    The origin of cavitation bubbles, cavitation nuclei, has been a subject of debate since the early years of cavitation research. This paper presents an analysis of a representative selection of experimental investigations of cavitation inception and the tensile strength of water. At atmospheric...... on the surface of particles and bounding walls. Such nuclei can be related to the full range of tensile strengths measured, when differences of experimental conditions are taken into consideration. The absence or presence of contamination on surfaces, as well as the structure of the surfaces, are central...... to explaining why the tensile strength of water varies so dramatically between the experiments reported. A model for calculation of the critical pressure of skin-covered free gas bubbles as well as that of interfacial gaseous nuclei covered by a skin is presented. This model is able to bridge the apparently...

  15. Two-Phase Cavitating Flow in Turbomachines

    Directory of Open Access Journals (Sweden)

    Sandor I. Bernad

    2012-11-01

    Full Text Available Cavitating flows are notoriously complex because they are highly turbulent and unsteady flows involving two species (liquid/vapor with a large density difference. These features pose a unique challenge to numerical modeling works. The study briefly reviews the methodology curently employed for industrial cavitating flow simulations using the two-phase mixture model. The two-phase mixture model is evaluated and validated using benchmark problem where experimental data are available. A 3D cavitating flow computation is performed for the GAMM Francis runner. The model is able to qualitatively predict the location and extent of the 3D cavity on the blade, but further investigation are needed to quatitatively assess the accuracy for real turbomachinery cavitating flows.

  16. Numerical analysis of cavitation within slanted axial-flow pump

    Institute of Scientific and Technical Information of China (English)

    张睿; 陈红勋

    2013-01-01

    In this paper, the cavitating flow within a slanted axial-flow pump is numerically researched. The hydraulic and cavitation performance of the slanted axial-flow pump under different operation conditions are estimated. Compared with the experimental hydraulic performance curves, the numerical results show that the filter-based model is better than the standard k-e model to predict the parameters of hydraulic performance. In cavitation simulation, compared with the experimental results, the proposed numerical method has good predicting ability. Under different cavitation conditions, the internal cavitating flow fields within slanted axial-flow pump are investigated. Compared with flow visualization results, the major internal flow features can be effectively grasped. In order to explore the origin of the cavitation performance breakdown, the Boundary Vorticity Flux (BVF) is introduced to diagnose the cavitating flow fields. The analysis results indicate that the cavitation performance drop is relevant to the instability of cavitating flow on the blade suction surface.

  17. Assessment of Cavitation Erosion with a Multiphase Reynolds-Averaged Navier-Stokes Method

    NARCIS (Netherlands)

    Li, Z.R.

    2012-01-01

    Cavitation erosion is one of the remarkable catastrophic consequences of cavitation. Predicting the cavitation aggressiveness quantitatively and predicting the most probable location of cavitation erosion are complex problems that currently still motivate an important amount of basic and applied res

  18. AN ATTRIBUTION OF CAVITATION RESONANCE: VOLUMETRIC OSCILLATIONS OF CLOUD

    Institute of Scientific and Technical Information of China (English)

    ZUO Zhi-gang; LI Sheng-cai; LIU Shu-hong; LI Shuang; CHEN Hui

    2009-01-01

    In order to further verify the proposed theory of cavitation resonance, as well as to proceed the investigations into microscopic level, a series of studies are being carried out on the Warwick venturi. The analysis of the oscillation characteristics of the cavitation resonance has conclusively verified the macro-mechanism proposed through previous studies on other cavitating flows by the authors. The initial observations using high-speed photographic approach have revealed a new attribution of cavitation resonance. That is, the volumetric oscillation of cavitation cloud is associated with the cavitation resonance, which is a collective behaviour of the bubbles in the cloud.

  19. Two-dimensional resonant magnetic soft X-ray scattering set-up for extreme sample environment.

    Science.gov (United States)

    Stanescu, Stefan; Mocuta, Cristian; Merlet, Frederic; Barbier, Antoine

    2013-01-01

    The newly built MagSAXS (magnetic small-angle X-ray scattering) set-up dedicated to the direct two-dimensional measurement of magnetic scattering using polarized synchrotron radiation in extreme sample environments is presented. Pure optical transport of the image is used to record the magnetic scattering with a two-dimensional CCD visible-light camera. The set-up is able to probe magnetic correlation lengths from the micrometer down to the nanometer scale. A detailed layout is presented along with preliminary results obtained at several beamlines at Synchrotron SOLEIL. The presented examples underline the wide range of possible applications spanning from correlation lengths determination to Fourier transform holography.

  20. Reflections of Setting up Research Team%组建科研团队的若干思考

    Institute of Scientific and Technical Information of China (English)

    夏斌

    2013-01-01

    This paper analyzed the importance and the problems encountered in the process of setting up research teams,as well as technology management for the formation of research teams should bear responsibilities,to set up the research team to undertake the major projects.%  阐述分析了组建科研团队的重要性和在组建过程中遇到的问题,以及作为科技管理部门为组建科研团队应当承担的责任,使组建的科研团队能够承担重大科技项目。

  1. Methods and Techniques of Enterprise Set-up Accounts%企业建账方法与技巧

    Institute of Scientific and Technical Information of China (English)

    卢恩平; 来臣军; 刘国华

    2015-01-01

    Set-up accounts methods and techniques are the basic business skills that every accountant should master. In this paper, different kinds of set-up accounts methods and techniques such as the initial establishment, combination, finishing the old account and separating a new account are discussed.%建账方法与技巧是每一名会计人员应掌握的基本业务技能,本文就企业初始设立、合并、年末结束旧账另立新账等不同情形的建账方法与技巧进行了探讨。

  2. Design of the Testing Set-up for a Nuclear Fuel Rod by Neutron Radiography at CARR

    Science.gov (United States)

    Wei, Guohai; Han, Songbai; Wang, Hongli; Hao, Lijie; Wu, Meimei; He, Linfeng; Wang, Yu; Liu, Yuntao; Sun, Kai; Chen, Dongfeng

    In this paper, an experimental set-up dedicated to non-destructively test a 15cm-long Pressurized Water Reactor (PWR) nuclear fuel rod by neutron radiography (NR) is described. It consists of three parts: transport container, imaging block and steel support. The design of the transport container was optimized with Monte-Carlo Simulation by the MCNP code. The material for the shell of the transport container was chosen to be lead with the thickness of 13 cm. Also, the mechanical devices were designed to control fuel rod movement inside the container. The imaging block was designed as the exposure platform, with three openings for the neutron beam, neutron converter foil, and specimen. Development and application of this experimental set-up will help gain much experience for investigating the actual irradiated fuel rod by neutron radiography at CARR in the future.

  3. An EPQ Model with Unit Production Cost and Set-Up Cost as Functions of Production Rate

    Directory of Open Access Journals (Sweden)

    Behrouz Afshar-Nadjafi

    2013-01-01

    Full Text Available Extensive research has been devoted to economic production quantity (EPQ problem. However, no attention has been paid to problems where unit production and set-up costs must be considered as functions of production rate. In this paper, we address the problem of determining the optimal production quantity and rate of production in which unit production and set-up costs are assumed to be continuous functions of production rate. Based on the traditional economic production quantity (EPQ formula, the cost function associated with this model is proved to be nonconvex and a procedure is proposed to solve this problem. Finally, utility of the model is presented using some numerical examples and the results are analyzed.

  4. Setting up the photoluminescence laboratory at ISOLDE & Perturbed Angular Correlation spectroscopy for BIO physics experiments using radioactive ions

    CERN Document Server

    Savva, Giannis

    2016-01-01

    The proposed project I was assigned was to set up the photoluminescence (PL) laboratory at ISOLDE, under the supervision of Karl Johnston. My first week at CERN coincided with the run of a BIO physics experiment using radioactive Hg(II) ions in which I also participated under the supervision of Stavroula Pallada. This gave me the opportunity to work in two projects during my stay at CERN and in the present report I describe briefly my contribution to them.

  5. Contralateral breast doses depending on treatment set-up positions for left-sided breast tangential irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Chan Seong; Park, Su Yeon; Kim, Jong Sik; Choi, Byeong Gi; Chung, Yoon Sun; Park, Won [Dept. of Radiation Oncology, Samsung Seoul Hospital, Seoul (Korea, Republic of)

    2015-12-15

    To evaluate Contralateral Breast Doses with Supine and Prone Positions for tangential Irradiation techniques for left-sided breast Cancer We performed measurements for contralateral doses using Human Phantom at each other three plans (conventional technique, Field-in-Field, IMRT, with prescription of 50 Gy/25fx). For the measurement of contralateral doses we used Glass dosimeters on the 4 points of Human Phantom surface (0 mm, 10 mm, 30 mm, 50 mm). For the position check at every measurements, we had taken portal images using EPID and denoted the incident points on the human phantom for checking the constancy of incident points. The contralateral doses in supine position showed a little higher doses than those in prone position. In the planning study, contralateral doses in the prone position increased mean doses of 1.2% to 1.8% at each positions while those in the supine positions showed mean dose decreases of 0.8% to 0.9%. The measurements using glass dosimeters resulted in dose increases (mean: 2.7%, maximum: 4% of the prescribed dose) in the prone position. In addition, the delivery techniques of Field-in-field and IMRT showed mean doses of 3% higher than conventional technique. We evaluated contralateral breast doses depending on different positions of supine and prone for tangential irradiations. For the phantom simulation of set-up variation effects on contralateral dose evaluation, although we used humanoid phantom for planning and measurements comparisons, it would be more or less worse set-up constancy in a real patient. Therefore, more careful selection of determination of patient set-up for the breast tangential irradiation, especially in the left-sided breast, should be considered for unwanted dose increases to left lung and heart. In conclusion, intensive patient monitoring and improved patient set-up verification efforts should be necessary for the application of prone position for tangential irradiation of left-sided breast cancer.

  6. Creating Innovators through setting up organizational Vision, Mission, and Core Values : a Strategic Model in Higher Education

    OpenAIRE

    Aithal, Sreeramana

    2016-01-01

    Vision, mission, objectives and core values play major role in setting up sustainable organizations. Vision and mission statements describe the organization’s goals. Core values and core principles represent the organization’s culture. In this paper, we have discussed a model on how a higher education institution can prosper to reach its goal of ‘creating innovators’ through its vision, mission, objectives and core values. A model for the core values required for a prospective ...

  7. Hydrodynamic modelling in the Polish Zone of the Baltic Sea - an overview of Polish achievements

    Directory of Open Access Journals (Sweden)

    Ewa Jasińska

    2003-03-01

    Full Text Available This paper gives a general overview of Polish experience and achievements with regard to hydrodynamic modelling in the Polish zone of the Baltic Sea. The first work started already at the end of the sixties when the first 1D and 2D hydrodynamic models were set up. With the development of numerical methods and increasing computational power a number of 1D, 2D and 3D models were set up and tested. Global, regional and local models cover the most important water bodies,i.e. the Pomeranian Bay - Szczecin Lagoon and Gulf of Gdansk - Vistula Lagoon systems.

  8. Numerical and Experimental Studies of Cavitation Behavior in Water-Jet Cavitation Peening Processing

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2013-01-01

    Full Text Available Water-jet cavitation peening (WCP is a new technology for the surface modification of metallic materials. The cavitation behavior in this process involves complex and changeable physics phenomena, such as high speed, high pressure, multiple phases, phase transition, turbulence, and unstable features. Thus, the cavitation behavior and impact-pressure distribution in WCP have always been key problems in this field. Numerous factors affect the occurrence of cavitation. These factors include flow-boundary conditions, absolute pressure, flow velocity, flow viscosity, surface tension, and so on. Among these factors, pressure and vapor fraction are the most significant. Numerical simulations are performed to determine the flow-field characteristics of both inside and outside the cavitating nozzle of a submerged water jet. The factors that influence the cavitation intensity of pressure are simulated. Fujifilm pressure-sensitive paper is used to measure the distribution of impact pressure along the jet direction during the WCP process. The results show that submerged cavitation jets can induce cavitation both inside and outside a conical nozzle and a convergent-divergent nozzle when the inlet pressure is 32 MPa. Moreover, the shock wave pressure induced by the collapse of the bubble group reaches up to 300 MPa.

  9. Synthesis and characterisation of polymeric nanofibers poly (vinyl alcohol and poly (vinyl alcohol/silica using indigenous electrospinning set up

    Directory of Open Access Journals (Sweden)

    K. Sasipriya

    2013-01-01

    Full Text Available Indigenous design and fabrication horizontal of electrospinning set up was developed to facilitate with double drum conveyor belt system to make ease in harvesting nanofibers rapidly. As a bench mark study, organic-inorganic nanofiber composite was synthesised employing our indigenous electrospinning set up. The aqueous solution of poly (vinyl alcohol and poly (vinyl alcohol/silica sol were employed to produce nanofiber mats in order to vary the experimental parameters such as voltage, solvent effect and the effect of catalyst. The synthesised pure electro spun poly (vinyl alcohol and poly (vinyl alcohol/silica sol fibers were characterized by Scanning electron microscopy (SEM, Atomic force microscopy (AFM and Fourier transform infra red spectroscopy (FTIR. According to the results, the fine polymeric nanofibers were achieved in the size range of 100-500 nm for pure poly (vinyl alcohol fiber and 100-700 nm for polyvinyl alcohol/silica and the constitution of silica in rendering better fiber mats with this double drum set up.

  10. Synthesis and characterisation of polymeric nanofibers poly (vinyl alcohol) and poly (vinyl alcohol)/silica using indigenous electrospinning set up

    Energy Technology Data Exchange (ETDEWEB)

    Sasipriya, K.; Suriyaprabha, R.; Prabu, P.; Rajendran, V., E-mail: veerajendran@gmail.com [Centre for Nanoscience and Technology, K. S. Rangasamy College of Technology, Tamil Nadu (India)

    2013-11-01

    Indigenous design and fabrication horizontal of electrospinning set up was developed to facilitate with double drum conveyor belt system to make ease in harvesting nanofibers rapidly. As a bench mark study, organic-inorganic nanofiber composite was synthesised employing our indigenous electrospinning set up. The aqueous solution of poly (vinyl alcohol) and poly (vinyl alcohol)/silica sol were employed to produce nanofiber mats in order to vary the experimental parameters such as voltage, solvent effect and the effect of catalyst. The synthesised pure electro spun poly (vinyl alcohol) and poly (vinyl alcohol)/silica sol fibers were characterized by Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Fourier transform infra red spectroscopy (FTIR). According to the results, the fine polymeric nanofibers were achieved in the size range of 100-500 nm for pure poly (vinyl alcohol) fiber and 100-700 nm for polyvinyl alcohol/silica and the constitution of silica in rendering better fiber mats with this double drum set up. (author)

  11. Model of Light Scattering in Cavitation Area

    Directory of Open Access Journals (Sweden)

    S. P. Skvortsov

    2015-01-01

    Full Text Available The offered work presents analysis of extinction mechanisms and justification of light scattering model in ultrasonic cavitation area to justify a control method of ultrasonic cavitation through its optical sounding by low-intensity laser radiation and through photo-detector record of last radiation.The analysis of the extinction mechanisms has shown that the most essential mechanism causing a change of the transmission coefficient with time is dispersion on pulsating cavitation bubbles. Other extinction mechanisms lead to the time-constant reduction of last radiation intensity and can be taken into consideration by normalizing a recorded transmission coefficient for a previously measured liquid transmission coefficient when there is no cavitation.The feature of light scattering on the cavitation bubbles is primary dispersion in a forward direction that is connected with great values of bubbles radius from units to hundreds of micrometers. In case of single bubbles, dispersion can be described by Mi's theory, and, as to the cavitation area, it is reasonable to use the theory of V. Tversky for multiple light scattering. Thus, dispersion section, according to the paradox of extinction, can be considered to be equal to doubled geometrical section of a bubble. With increasing bubble radius the transmission coefficient monotonically decreases. So, the law of bubble pulsations and the model of light scattering define the law of changing transmission coefficient.Therefore, the cavitation area with its optical sounding acts as a peculiar opto-acoustic modulator. Thus, the demodulated signal of a photo-detector comprises information on pulsations of bubbles.The paper examines the influence of cavitation area thickness and bubbles concentration on the transmission coefficient. It shows a type of transmission coefficient dependence on the radius of cavitation bubbles.The optical sounding method is attractive because it allows us to obtain data on the

  12. Numerical analysis of the interactions of sheet cavitation and cloud cavitation around a hydrofoil

    Science.gov (United States)

    Pan, D. Z.; Zhang, D. S.; Wang, H. Y.; Shi, W. D.; Shi, L.

    2015-01-01

    Partial cavitation and cloud cavitation on NACA66(MOD) was studied based on PANS turbulence model combined with the Zwart cavitation model. The results agree well with the data from the experimental results. The existence of a kind of unsteady characteristics of cloud cavitation is analysed in details. The reasons for the inhibition mechanism of the sheet cavitation are discussed. Pressure shock wave occurs near the tailing edge of the hydrofoil when the collapse of cloud is so large leading to great influence on the cavity closed to the leading edge. The evolution of the pressure peak and its propagation toward the leading edge were investigated through the study of the time domain signal of the monitor points along the streamline of flow. Finally, the propagation of the pressure wave on the suction side was further investigated through analysing the spatial-time history of wall pressure.

  13. Numerical prediction of impact force in cavitating flows

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, B [Department of Thermal Engineering, State Key Laboratory of Hydroscience and Engineering, Tsinghua Univeersity, Beijing, 100084 (China); Wang, H, E-mail: bszhu@mail.tsinghua.edu.c [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China)

    2010-08-15

    An analytical method including a macroscopic cavitation model based on the homogeneous flow theory and a microscopic cavitation model based on the bubble dynamic was proposed for the prediction of the impact force caused by cavitation bubbles collapse in cavitating flows. A Large Eddy Simulation (LES) solver incorporated the macroscopic cavitation model was applied to simulate the unsteady cavitating flows. Based on the simulated flow field, the evolution of the cavitation bubbles was determined by a microscopic cavitation model from the resolution of a Rayleigh-Plesset equation including of the effects of the surface tension, the viscosity and compressibility of fluid, thermal conduction and radiation, the phase transition of water vapor at interface and chemical reactions. The cavitation flow around a hydrofoil was simulated to validate the macroscopic cavitation model. A good quantitative agreement was obtained between the prediction and the experiment. The proposed analytical method was applied to predict the impact force at cavitation bubbles collapse on a KT section in cavitating flows. It was found that the shock pressure caused by cavitation bubble collapse is very high. The impact force was predicted accurately comparing with the experimental data.

  14. Cavitation Measurement during Sonic and Ultrasonic Activated Irrigation

    NARCIS (Netherlands)

    Macedo, Ricardo; Verhaagen, Bram; Rivas, David Fernandez; Versluis, Michel; Wesselink, Paul; van der Sluis, Luc

    Introduction: The aims of this study were to quantify and to visualize the possible occurrence of transient cavitation (bubble formation and implosion) during sonic and ultrasonic (UAI) activated irrigation. Methods: The amount of cavitation generated around several endodontic instruments was

  15. Advanced experimental and numerical techniques for cavitation erosion prediction

    CERN Document Server

    Chahine, Georges; Franc, Jean-Pierre; Karimi, Ayat

    2014-01-01

    This book provides a comprehensive treatment of the cavitation erosion phenomenon and state-of-the-art research in the field. It is divided into two parts. Part 1 consists of seven chapters, offering a wide range of computational and experimental approaches to cavitation erosion. It includes a general introduction to cavitation and cavitation erosion, a detailed description of facilities and measurement techniques commonly used in cavitation erosion studies, an extensive presentation of various stages of cavitation damage (including incubation and mass loss), and insights into the contribution of computational methods to the analysis of both fluid and material behavior. The proposed approach is based on a detailed description of impact loads generated by collapsing cavitation bubbles and a physical analysis of the material response to these loads. Part 2 is devoted to a selection of nine papers presented at the International Workshop on Advanced Experimental and Numerical Techniques for Cavitation Erosion (Gr...

  16. DETECTION OF CAVITATION IN CENTRIFUGAL PUMP BY VIBRATION METHODS

    Institute of Scientific and Technical Information of China (English)

    NI Yongyan; YUAN Shouqi; PAN Zhongyong; YUAN Jianping

    2008-01-01

    For the purpose of detecting the cavitation of centrifugal pump onsite and real time, the vibration signals on varied operation conditions of both cavitation and non-cavitation obtained through acceleration sensors were analyzed. When cavitation occurs, the cavities near the leading edge of the blade will appear periodic oscillating, which will induce quasi-synchronous vibration. The frequency of the quasi-synchronous vibration symmetrically appears on the two sides of the blade passing frequency, by which the cavitation incipiency can be detected. During the developing process of the cavitation, as the severe complexity of the unsteady flow, it is very difficult to detect the development of cavitation by classical analysis methods. Fractal method of Higuchi is successfully used for detecting the incipiency, fully development of cavitation and the development between them.

  17. Setting up R608

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    This experiment was designed by the Los Angeles (UCLA)-Saclay Collaboration to study large-X hadron physics and correlations with central region phenomena (Annual Report 1979 p. 115, Figs. 4, 5, and Annual Report 1980 p. 105).

  18. Elasto-hydrodynamic lubrication

    CERN Document Server

    Dowson, D; Hopkins, D W

    1977-01-01

    Elasto-Hydrodynamic Lubrication deals with the mechanism of elasto-hydrodynamic lubrication, that is, the lubrication regime in operation over the small areas where machine components are in nominal point or line contact. The lubrication of rigid contacts is discussed, along with the effects of high pressure on the lubricant and bounding solids. The governing equations for the solution of elasto-hydrodynamic problems are presented.Comprised of 13 chapters, this volume begins with an overview of elasto-hydrodynamic lubrication and representation of contacts by cylinders, followed by a discussio

  19. Elementary classical hydrodynamics

    CERN Document Server

    Chirgwin, B H; Langford, W J; Maxwell, E A; Plumpton, C

    1967-01-01

    Elementary Classical Hydrodynamics deals with the fundamental principles of elementary classical hydrodynamics, with emphasis on the mechanics of inviscid fluids. Topics covered by this book include direct use of the equations of hydrodynamics, potential flows, two-dimensional fluid motion, waves in liquids, and compressible flows. Some general theorems such as Bernoulli's equation are also considered. This book is comprised of six chapters and begins by introducing the reader to the fundamental principles of fluid hydrodynamics, with emphasis on ways of studying the motion of a fluid. Basic c

  20. Therapeutic education unit for heart failure: setting-up and difficulties. Initial evaluation of the I-CARE programme.

    Science.gov (United States)

    Juillière, Yves; Jourdain, Patrick; Roncalli, Jérome; Boireau, Amélie; Guibert, Hélène; Lambert, Hélène; Spinazze, Laure; Jondeau, Guillaume; Sonnier, Pierre; Rouanne, Céline; Bidet, Angélique; Sandrin-Berthon, Brigitte; Trochu, Jean-Nöel

    2009-01-01

    Education programmes are required in chronic diseases. The insuffisance cardiaque : éducation thérapeutique (I-CARE) programme was developed in France to promote the setting-up of therapeutic education units for chronic heart failure. To evaluate the setting-up of such units, assessing the influence of training on the creation and organization of the unit, the problems encountered and the contribution of the dedicated educational tools. We submitted a questionnaire to the first 136 trained centres. The questionnaire was divided into two sections: one section dealing with educational practices and the other with the advantages and disadvantages of the tools provided. The participation rate reached 69.1%. Seventy-four centres (78.7%) declared themselves to be active in therapeutic education. Unit educational activities determined an educational diagnosis (89.2% of the centres) and provided education by means of collective workshops (73.0%) or one-to-one teaching sessions (75.7%). A complete education programme for a patient consisted of a median of four sessions (25th-75th percentile, 2-5 sessions) and lasted for a median of 6 h (25th-75th percentile, 4-10 h). The education team was multidisciplinary and usually included a nurse (93.2%), a dietician (78.4%), a cardiologist (71.6%) and a physiotherapist (40.5%). Heart failure educational tools were used only in part in most centres (89.2%). All advantages and disadvantages were recorded. This first evaluation of the setting-up of therapeutic education units in the I-CARE programme has yielded promising results, despite expected difficulties. The effects of therapeutic education on the behaviour of heart failure patients remain to be determined.

  1. The optimisation of the fast neutron and gamma-ray transmission set-up for moisture measurement of coke.

    Science.gov (United States)

    Cywicka-Jakiel, T; Łoskiewicz, J; Tracz, G

    2003-01-01

    In the present paper, modelling calculations with the Monte Carlo (MCNP4C) code were performed for the optimisation of the fast neutron and gamma-ray transmission, set-up, used for the humidity measurement of coke. The optimisation focused on maximising the sensitivity of the neutron flux to humidity changes and on lowering neutron-counting error, both leading to higher accuracy of coke moisture determination. Different materials used for the source shielding and neutron collimation, together with different dimensions of the neutron collimators were studied. The results obtained from the Monte Carlo modelling correlate with the real instrument performance.

  2. MARKETING STRATEGY FOR SETTING UP AN OWN COFFEE SHOP IN CHINA : Using Starbucks as a case study

    OpenAIRE

    Wei , ChiJiao

    2016-01-01

    The thesis aimed to find out a suitable marketing strategy and making a marketing plan for setting up an own coffee shop in Shanghai, China. Coffee was one of the most popular drinks in the world and coffee has been accepted by more and more Chinese people. Coffee industry was well-received choice for the entrepreneurs to start up their own business in China. Marketing strategy played an important role in the intense market competition. A successful marketing strategy could help the coffee co...

  3. Spectroscopy of laser-produced plasmas: Setting up of high-performance laser-induced breakdown spectroscopy system

    Indian Academy of Sciences (India)

    V K Unnikrishnan; Kamlesh Alti; Rajesh Nayak; Rodney Bernard; V B Kartha; C Santhosh; G P Gupta; B M Suri

    2010-12-01

    It is a well-known fact that laser-induced breakdown spectroscopy (LIBS) has emerged as one of the best analytical techniques for multi-elemental compositional analysis of samples. We report assembling and optimization of LIBS set up using high resolution and broad-range echelle spectrograph coupled to an intensified charge coupled device (ICCD) to detect and quantify trace elements in environmental and clinical samples. Effects of variations of experimental parameters on spectroscopy signals of copper and brass are reported. Preliminary results of some plasma diagnostic calculations using recorded time-resolved optical emission signals are also reported for brass samples.

  4. MARKETING STRATEGY FOR SETTING UP AN OWN COFFEE SHOP IN CHINA : Using Starbucks as a case study

    OpenAIRE

    Wei , ChiJiao

    2016-01-01

    The thesis aimed to find out a suitable marketing strategy and making a marketing plan for setting up an own coffee shop in Shanghai, China. Coffee was one of the most popular drinks in the world and coffee has been accepted by more and more Chinese people. Coffee industry was well-received choice for the entrepreneurs to start up their own business in China. Marketing strategy played an important role in the intense market competition. A successful marketing strategy could help the coffee co...

  5. Influence of microparticle size on cavitation noise during ultrasonic vibration

    Directory of Open Access Journals (Sweden)

    H. Ge

    2015-09-01

    Full Text Available The cavitation noise in the ultrasonic vibration system was found to be influenced by the size of microparticles added in water. The SiO2 microparticles with the diameter smaller than 100 μm reduced the cavitation noise, and the reason was attributed to the constrained oscillation of the cavitation bubbles, which were stabilized by the microparticles.

  6. Noise Caused by Cavitating Butterfly and Monovar Valves

    Science.gov (United States)

    HASSIS, H.

    1999-08-01

    An experimental study of the effects of cavitation was carried out through an analysis of cavitating Butterfly and Monovar values. Focus is particularly placed on both unsteady pressure and acoustic pressure fluctuations. In this paper, the effects of cavitation on local fluctuation pressure (turbulence), acoustic propagation (damping and sound velocity), resonance frequencies and level of noise are presented.

  7. Static and Transient Cavitation Threshold Measurements for Mercury

    Energy Technology Data Exchange (ETDEWEB)

    Moraga, F.; Taleyarkhan, R.P.

    1999-11-14

    Transient and static cavitation thresholds for mercury as a function of the cover gas (helium or air), and pressure are reported. Both static and transient cavitation onset pressure thresholds increase linearly with cover gas pressure. Additionally, the cavitation thresholds as a function of dissolved gases were also measured and are reported.

  8. Real-time two-dimensional imaging of microbubble cavitation

    Science.gov (United States)

    Vignon, Francois; Shi, W. T.; Powers, J. E.; Liu, J.; Drvol, L.; Lof, J.; Everbach, C.; Gao, S.; Xie, F.; Porter, T.

    2012-10-01

    Ultrasound cavitation of microbubble contrast agents has a potential for therapeutic applications, including sonothrombolysis in acute ischemic stroke. For safety, efficacy, and reproducibility of treatment, it is critical to evaluate the cavitation state (e.g. stable versus inertial forms of cavitation) and intensity in and around a treatment area. Acoustic Passive Cavitation Detectors (PCDs) have been used but do not provide spatial information. This paper presents a prototype of a 2D cavitation imager capable of producing images of the dominant cavitation state and intensity in a region of interest at a frame rate of 0.6Hz. The system is based on a modified ultrasound scanner (iE33, Philips) with a sector imaging probe (S5-1). Cavitation imaging is based on the spectral analysis of the acoustic signal radiated by the cavitating microbubbles: ultraharmonics of the excitation frequency indicate stable cavitation, while noise bands indicate inertial cavitation. The system demonstrates the capability to robustly identify stable and inertial cavitation thresholds of Definity microbubbles (Lantheus) in a vessel phantom through 3 ex-vivo human temporal bones, as well as to spatially map cavitation activities.

  9. Modelling vaporous cavitation on fluid transients

    CERN Document Server

    Shu, Jian-Jun

    2014-01-01

    A comprehensive study of the problem of modelling vaporous cavitation in transmission lines is presented. The two-phase homogeneous equilibrium vaporous cavitation model which has been developed is compared with the conventional column separation model. The latter predicts unrealistically high pressure spikes because of a conflict arising from the prediction of negative cavity sizes if the pressure is not permitted to fall below the vapour pressure, or the prediction of negative absolute pressures if the cavity size remains positive. This is verified by a comparison of predictions with previously published experimental results on upstream, midstream and downstream cavitation. The new model has been extended to include frequency-dependent friction. The characteristics predicted by the frequency-dependent friction model show close correspondence with experimental data.

  10. Cavitation erosion of NiAl

    Energy Technology Data Exchange (ETDEWEB)

    Akhtar, A. [Powertech Labs. Inc., Surrey, British Columbia (Canada)]|[Univ. of British Columbia (Canada). Metals and Materials Engineering Dept.; Salvi, R. [Univ. of British Columbia (Canada). Metals and Materials Engineering Dept.; Sikka, V.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1999-02-01

    Vibratory cavitation erosion tests were carried out on as-cast NiAl intermetallic compounds containing 46.5 to 62.1 at. pct Ni. The erosion rate decreased with increasing nickel content by over two orders of magnitude, from a high of 16.4 to 0.11 mg{center_dot}h{sup {minus}1}. These low erosion rates exhibited by the nickel-rich alloys containing 58 and 62.1 at. pct Ni, the interruptions in their mass loss with time, and the unusual effects associated with surface finish and intensity of cavitation were found to be associated with the stress-induced martensitic transformation. Alloys containing 58 to 62 at. pct Ni have the potential for use as materials for the cavitation protection of hydraulic machinery.

  11. Fundamental studies on cavitation melt processing

    Science.gov (United States)

    Tzanakis, I.; Hodnett, M.; Lebon, G. S. B.; Eskin, D. G.; Pericleous, K.

    2016-05-01

    The application of ultrasound to industrial casting processes has attracted research interest during the last 50 years. However, the transfer and scale-up of this advanced and promising technology to industry has been hindered by difficulties in treating large volumes of liquid metal due to the lack of understanding of certain fundamentals. In the current study experimental results on ultrasonic processing in deionised water and in liquid aluminium (Al) are reported. Cavitation activity was determined in both liquid environments and acoustic pressures were successfully measured using an advanced high-temperature cavitometer sensor. Results showed that highest cavitation intensity in the liquid bulk is achieved at lower amplitudes of the sonotrode tip than the maximum available, suggesting nonlinearity in energy transfer to the liquid, while the location of the sonotrode is seen to substantially affect cavitation activity within the liquid. Estimation of real-time acoustic pressures distributed inside a crucible with liquid Al was performed for the first time.

  12. Analogy between fluid cavitation and fracture mechanics

    Science.gov (United States)

    Hendricks, R. C.; Mullen, R. L.; Braun, M. J.

    1983-01-01

    When the stresses imposed on a fluid are sufficiently large, rupture or cavitation can occur. Such conditions can exist in many two-phase flow applications, such as the choked flows, which can occur in seals and bearings. Nonspherical bubbles with large aspect ratios have been observed in fluids under rapid acceleration and high shear fields. These bubbles are geometrically similar to fracture surface patterns (Griffith crack model) existing in solids. Analogies between crack growth in solid and fluid cavitation are proposed and supported by analysis and observation (photographs). Healing phenomena (void condensation), well accepted in fluid mechanics, have been observed in some polymers and hypothesized in solid mechanics. By drawing on the strengths of the theories of solid mechanics and cavitation, a more complete unified theory can be developed.

  13. Performance of the AGATA γ-ray spectrometer in the PreSPEC set-up at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Lalović, N., E-mail: Natasa.Lalovic@nuclear.lu.se [Department of Physics, Lund University, SE-22100 Lund (Sweden); GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Louchart, C. [Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany); Michelagnoli, C. [GANIL, CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen (France); Perez-Vidal, R.M. [Instituto de Fisica Corpuscular, CSIC-Universitat de Valencia, E-46920 Valencia (Spain); Ralet, D. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Institut für Kernphysik, Technische Universität Darmstadt, D-64289 Darmstadt (Germany); Gerl, J. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Rudolph, D. [Department of Physics, Lund University, SE-22100 Lund (Sweden); Arici, T. [Justus-Liebig-Universität Giessen, D-35392 Giessen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Bazzacco, D. [INFN Sezione di Padova and Dipartimento di Fisica, Universitàdi Padova, IT-35131 Padova (Italy); Clément, E. [GANIL, CEA/DSM-CNRS/IN2P3, BP 55027, F-14076 Caen (France); Gadea, A. [Instituto de Fisica Corpuscular, CSIC-Universitat de Valencia, E-46920 Valencia (Spain); Kojouharov, I. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Korichi, A. [CSNSM, F-91405 Orsay Campus (France); Labiche, M. [STFC Daresbury Laboratory, Daresbury, WA4 4AD Warrington (United Kingdom); Ljungvall, J. [CSNSM, F-91405 Orsay Campus (France); and others

    2016-01-11

    In contemporary nuclear physics, the European Advanced GAmma Tracking Array (AGATA) represents a crucial detection system for cutting-edge nuclear structure studies. AGATA consists of highly segmented high-purity germanium crystals and uses the pulse-shape analysis technique to determine both the position and the energy of the γ-ray interaction points in the crystals. It is the tracking algorithms that deploy this information and enable insight into the sequence of interactions, providing information on the full or partial absorption of the γ ray. A series of dedicated performance measurements for an AGATA set-up comprising 21 crystals is described. This set-up was used within the recent PreSPEC–AGATA experimental campaign at the GSI Helmholtzzentrum für Schwerionenforschung. Using the radioactive sources {sup 56}Co, {sup 60}Co and {sup 152}Eu, absolute and normalized efficiencies and the peak-to-total of the array were measured. These quantities are discussed using different data analysis procedures. The quality of the pulse-shape analysis and the tracking algorithm are evaluated. The agreement between the experimental data and the Geant4 simulations is also investigated.

  14. Technical note: An experimental set-up to measure latent and sensible heat fluxes from (artificial) plant leaves

    Science.gov (United States)

    Schymanski, Stanislaus J.; Breitenstein, Daniel; Or, Dani

    2017-07-01

    Leaf transpiration and energy exchange are coupled processes that operate at small scales yet exert a significant influence on the terrestrial hydrological cycle and climate. Surprisingly, experimental capabilities required to quantify the energy-transpiration coupling at the leaf scale are lacking, challenging our ability to test basic questions of importance for resolving large-scale processes. The present study describes an experimental set-up for the simultaneous observation of transpiration rates and all leaf energy balance components under controlled conditions, using an insulated closed loop miniature wind tunnel and artificial leaves with pre-defined and constant diffusive conductance for water vapour. A range of tests documents the above capabilities of the experimental set-up and points to potential improvements. The tests reveal a conceptual flaw in the assumption that leaf temperature can be characterized by a single value, suggesting that even for thin, planar leaves, a temperature gradient between the irradiated and shaded or transpiring and non-transpiring leaf side can lead to bias when using observed leaf temperatures and fluxes to deduce effective conductances to sensible heat or water vapour transfer. However, comparison of experimental results with an explicit leaf energy balance model revealed only minor effects on simulated leaf energy exchange rates by the neglect of cross-sectional leaf temperature gradients, lending experimental support to our current understanding of leaf gas and energy exchange processes.

  15. Technical note: An experimental set-up to measure latent and sensible heat fluxes from (artificial plant leaves

    Directory of Open Access Journals (Sweden)

    S. J. Schymanski

    2017-07-01

    Full Text Available Leaf transpiration and energy exchange are coupled processes that operate at small scales yet exert a significant influence on the terrestrial hydrological cycle and climate. Surprisingly, experimental capabilities required to quantify the energy–transpiration coupling at the leaf scale are lacking, challenging our ability to test basic questions of importance for resolving large-scale processes. The present study describes an experimental set-up for the simultaneous observation of transpiration rates and all leaf energy balance components under controlled conditions, using an insulated closed loop miniature wind tunnel and artificial leaves with pre-defined and constant diffusive conductance for water vapour. A range of tests documents the above capabilities of the experimental set-up and points to potential improvements. The tests reveal a conceptual flaw in the assumption that leaf temperature can be characterized by a single value, suggesting that even for thin, planar leaves, a temperature gradient between the irradiated and shaded or transpiring and non-transpiring leaf side can lead to bias when using observed leaf temperatures and fluxes to deduce effective conductances to sensible heat or water vapour transfer. However, comparison of experimental results with an explicit leaf energy balance model revealed only minor effects on simulated leaf energy exchange rates by the neglect of cross-sectional leaf temperature gradients, lending experimental support to our current understanding of leaf gas and energy exchange processes.

  16. A dynamic method based on the specific substrate uptake rate to set up a feeding strategy for Pichia pastoris.

    Science.gov (United States)

    Dietzsch, Christian; Spadiut, Oliver; Herwig, Christoph

    2011-03-03

    Pichia pastoris is one of the most important host organisms for the recombinant production of proteins in industrial biotechnology. To date, strain specific parameters, which are needed to set up feeding profiles for fed batch cultivations, are determined by time-consuming continuous cultures or consecutive fed batch cultivations, operated at different parameter sets. Here, we developed a novel approach based on fast and easy to do batch cultivations with methanol pulses enabling a more rapid determination of the strain specific parameters specific substrate uptake rate qs, specific productivity qp and the adaption time (Δtimeadapt) of the culture to methanol. Based on qs, an innovative feeding strategy to increase the productivity of a recombinant Pichia pastoris strain was developed. Higher specific substrate uptake rates resulted in increased specific productivity, which also showed a time dependent trajectory. A dynamic feeding strategy, where the setpoints for qs were increased stepwise until a qs max of 2.0 mmol·g-1·h-1 resulted in the highest specific productivity of 11 U·g-1·h-1. Our strategy describes a novel and fast approach to determine strain specific parameters of a recombinant Pichia pastoris strain to set up feeding profiles solely based on the specific substrate uptake rate. This approach is generic and will allow application to other products and other hosts.

  17. A dynamic method based on the specific substrate uptake rate to set up a feeding strategy for Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Herwig Christoph

    2011-03-01

    Full Text Available Abstract Background Pichia pastoris is one of the most important host organisms for the recombinant production of proteins in industrial biotechnology. To date, strain specific parameters, which are needed to set up feeding profiles for fed batch cultivations, are determined by time-consuming continuous cultures or consecutive fed batch cultivations, operated at different parameter sets. Results Here, we developed a novel approach based on fast and easy to do batch cultivations with methanol pulses enabling a more rapid determination of the strain specific parameters specific substrate uptake rate qs, specific productivity qp and the adaption time (Δtimeadapt of the culture to methanol. Based on qs, an innovative feeding strategy to increase the productivity of a recombinant Pichia pastoris strain was developed. Higher specific substrate uptake rates resulted in increased specific productivity, which also showed a time dependent trajectory. A dynamic feeding strategy, where the setpoints for qs were increased stepwise until a qs max of 2.0 mmol·g-1·h-1 resulted in the highest specific productivity of 11 U·g-1·h-1. Conclusions Our strategy describes a novel and fast approach to determine strain specific parameters of a recombinant Pichia pastoris strain to set up feeding profiles solely based on the specific substrate uptake rate. This approach is generic and will allow application to other products and other hosts.

  18. Phase-shift Cavity Ring Down Spectroscopy Set-up for NO2 Sensing : Design and Fabrication

    Directory of Open Access Journals (Sweden)

    Cherry Dhiman

    2015-03-01

    Full Text Available An indigenously designed cavity ring down spectroscopy cell of 80 cm length of mild steel material was fabricated by attaching two 1″ diameter high reflecting concave mirrors with reflectivity 99.997 % at 405 nm and radius of curvature was 1 m in specially designed mirror holding assemblies to the cell at two ends. Fine alignment of the resonator is facilitated with three tip-tilt adjusting screws to the mirror-mounting plate assembly. The PS-CRDS experimental set-up is evaluated by measuring the phase shift values corresponding to the absorption of NO2 gas filled at low pressures in the cell. The limit of detection of pure NO2 using the set-up under given conditions of Ar @ 50 mbar is estimated to be 1.50 × 1011 cm-3 and @ 60 mbar as 2 × 1011 cm-3.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.25-30, DOI:http://dx.doi.org/10.14429/dsj.65.7790

  19. The influence of laboratory set-up in usability tests: effects on user performance, subjective ratings and physiological measures.

    Science.gov (United States)

    Sonderegger, Andreas; Sauer, Juergen

    2009-11-01

    This article examines the influences of situational factors on user behaviour in usability tests. Sixty participants carried out two tasks on a computer-simulated prototype of a mobile phone. Employing a 3 x 2 mixed experimental design, laboratory set-up was varied as a between-subjects variable (presence of facilitator and two non-interactive observers, presence of facilitator or no person present) while task difficulty was manipulated as a within-subjects variable (low vs. high). Performance data, subjective measures and physiological parameters (e.g. heart rate variability) were taken. The results showed that the presence of non-interactive observers during a usability test led to a physiological stress response, decreased performance on some measures and affected the emotional state of test participants. The presence of a facilitator (i.e. a participating observer) also influenced the emotional state of the test participant. Practitioners involved in usability testing need to be aware of undue influences of observers, in particular, if the observers are non-interactive. The findings presented in this paper have implications for the practice of usability testing. They indicated a considerable influence of observers on test participants (physiology and emotions) and on the outcomes of usability tests (performance measures). This should be considered when selecting the set-up of a usability testing procedure.

  20. An O(a) modified lattice set-up of the Schr\\"odinger functional in SU(3) gauge theory

    CERN Document Server

    Pérez-Rubio, Paula; Takeda, Shinji

    2011-01-01

    The set-up of the QCD Schr\\"odinger functional (SF) on the lattice with staggered quarks requires an even number of points $L/a$ in the spatial directions, while the Euclidean time extent of the lattice, $T/a$, must be odd. Identifying a unique renormalisation scale, $L=T$, is then only possible up to O($a$) lattice artefacts. In this article we study such lattices in the pure SU(3) gauge theory, where we can also compare to the standard set-up. We consider the SF coupling as obtained from the variation of an SU(3) Abelian and spatially constant background field. The O($a$) lattice artefacts can be cancelled by the existing O($a$) boundary counterterm. However, its coefficient, $\\ct$, differs at the tree-level from its standard value, so that one first needs to re-determine the induced background gauge field. The perturbative one-loop correction to the coupling allows to determine $\\ct$ to one-loop order. A few numerical simulations serve to demonstrate that residual cutoff effects in the step scaling functio...

  1. Parallel aligned liquid crystal on silicon display based optical set-up for the generation of polarization spatial distributions

    Science.gov (United States)

    Estévez, Irene; Lizana, Angel; Zheng, Xuejie; Peinado, Alba; Ramírez, Claudio; Martínez, Jose Luis; Márquez, Andrés.; Moreno, Ignacio; Campos, Juan

    2015-06-01

    Liquid Crystals on Silicon (LCOS) displays are a type of LCDs that work in reflection. Such devices, due to the double pass that the light beam performs through the LC cells, lead to larger phase modulation than transmissive LCDs with the same thickness. By taking advantage of this modulation capability exhibited by LCOS displays, we propose a new experimental set-up which is able to provide customized state of polarization spatial distributions just by means of a single LCOS display. To this aim, a double reflection on different halves of the display is properly performed. This fact is achieved by including a compact optical system that steers the light and performs a proper polarization plane rotation. The set-up has been experimentally implemented and some experimental concerns are discussed. The suitability of the system is provided by generating different experimental spatial distributions of polarization. In this regard, well-known polarization distributions, as axial, azimuthal or spiral linear polarization patterns are here provided. Based on the excellent results obtained, the suitability of the system to generate different spatially variant distributions of polarization is validated.

  2. On the mechanism of explosive eruption of mount erebus volcano: the dynamics of the rupture structure in a cavitating layer

    Science.gov (United States)

    Bol'shakova, E. S.; Kedrinskiy, V. K.

    2016-10-01

    This paper presents the results of an experimental simulation of rupture development in heavily cavitating magma melt flow in volcanic conduits and its effect on the structure of explosive volcanic eruptions. The dynamics of the state of a layer of distilled water (similar in the density of cavitation nuclei to magma melt) under shock-wave loading was studied. The experiments were performed using electromagnetic hydrodynamic shock tubes (EM HST) with maximum capacitor bank energy of up to 100 J and 5 kJ. It was found that the topology of the rupture formed on the membrane surface did not change during its development. Empirical estimates were obtained for the proportion of the capacitor bank energy expended in the development of the rupture and the characteristic time of its existence. The study revealed a number of fundamentally new physical effects in the cavity dynamics in a cavitating medium: a cavitation “boundary layer” is formed on the surface of the quasi-empty rupture, which is transformed into a cluster of high energy density upon closure of the flow.

  3. Surface imaging, portal imaging, and skin marker set-up vs. CBCT for radiotherapy of the thorax and pelvis

    Energy Technology Data Exchange (ETDEWEB)

    Pallotta, Stefania; Bucciolini, Marta [Universita degli Studi di Firenze, Dipartimento di Scienze Biomediche Sperimentali e Cliniche, Florence (Italy); AOU Careggi, Sezione di Fisica Medica, Florence (Italy); Vanzi, Eleonora; Marrazzo, Livia [AOU Careggi, Sezione di Fisica Medica, Florence (Italy); Simontacchi, Gabriele; Paiar, Fabiola [AOU Careggi, Sezione di Radioterapia, Florence (Italy); Ceroti, Marco [ISPO, U.O. Epidemiologia Molecolare e Nutrizionale, Florence (Italy); Livi, Lorenzo [Universita degli Studi di Firenze, Dipartimento di Scienze Biomediche Sperimentali e Cliniche, Florence (Italy); AOU Careggi, Sezione di Radioterapia, Florence (Italy)

    2015-09-15

    The aim of this study was to compare surface imaging, portal imaging, and skin marker set-up in radiotherapy of thoracic and pelvic regions, using cone beam computed tomography (CBCT) data as the gold standard. Twenty patients were included in this study. CBCT, surface acquisition (SA), and two orthogonal portal images (PI) were acquired during the first four treatment sessions. Patient set-up corrections, obtained by registering the planning CT with CBCT, were used as the gold standard. Registration results of the PI and SA were evaluated and compared with those obtained with CBCT. The advantage derived from using SA or PI verification systems over a skin marker set-up was also quantified. A statistically significant difference between PI and SA (in favour of PI) was observed in seven patients undergoing treatment of the pelvic region and in two patients undergoing treatment of the thoracic region. The use of SA or PI, compared with a skin marker set-up, improved patient positioning in 50% and 57 % of the thoracic fractions, respectively. For pelvic fractions, the use of PI was beneficial in 73 % of the cases, while the use of SA was beneficial in only 45 %. Patient positioning worsened with SA, particularly along longitudinal and vertical directions. PI yielded more accurate registration results than SA for both pelvic and thoracic fractions. Compared with the skin marker set-up, PI performances were superior to SA for pelvic fractions while comparable results were obtained for thoracic fractions. (orig.) [German] Ziel dieser Studie ist der Vergleich der Patientenpositionierung mittels der 3-D/4-D-Erfassung der Patientenoberflaeche durch ein Abtastsystem, kV/MV-Verifikationsaufnahmen mit Hochenergiebildsystemen und Markierungen auf der Haut bei Bestrahlungen im Thorax- bzw. Beckenbereich. Als Goldstandard zum Vergleich dienten CBCT(''cone beam computed tomography'')-Aufnahmen. Die Studie basiert auf Untersuchungen an 20 Patienten. Es wurden

  4. Single-phase and modified turbulence models for simulation of unsteady cavitating flows

    Energy Technology Data Exchange (ETDEWEB)

    Basuki, W.; Schnerr, G.H.; Yuan, W. [Univ. Karlsruhe (Germany)

    2003-03-01

    The aim of this research is to provide a physical complete and numerical efficient simulation method to predict developed cavitation in hydrodynamic turbomachinery as well as in micro fluid dynamic applications, e.g. in high pressure injection nozzles of combustion engines. Cavitating two-phase flows are always very unstable, highly unsteady, 3-D and turbulent. To understand cavitation dynamics and its interaction with viscous effects like boundary layers and separation, we introduce the single-phase turbulence k - {omega} model of Wilcox without modifications with respect to dispersed structures of bubbly liquids, which overestimates viscous effects in the transitional regime between the vapor and liquid phase and tends to suppress typical cavitation instabilities. Consequently our further approach consists of modifications of the single-phase Wilcox model to account for the strong nonlinear variation of the turbulent viscosity {mu}{sub t}, depending on the local void fraction {alpha}. The key issue of all numerical methods for simulation of cavitating flows is the treatment of the sudden density change of the fluid, in cold water up to 40.000:1, embedded in a global incompressible liquid flow. Here the two-phase fluid is modeled as dispersed mixture of an incompressible liquid and tiny vapor bubbles which grow or collapse, accordingly to the local static pressure and their convective transport. Therefore, the standard VOF method for capturing distinct interfaces without phase transition, e.g. free surface flow or single bubbles, is extended to include phase transition of dispersed mixtures. For simulation of bubble dynamics we apply the Rayleigh equation, which is completed by an energy balance to account for thermal effects, if hot water or if technical fluids others than water, e.g. refrigerants, with high vapor densities are considered. By using our CFD tool CAVKA we present examples of cavitating flow around hydrofoils and through single hole injection

  5. The Hydroelastic Response of a Flexible Surface-Piercing Strut in Wetted, Ventilated, and Cavitating Flows

    Science.gov (United States)

    Harwood, Casey; Ward, Jacob; Young, Yin Lu; Felli, Mario; Falchi, Massimo; Ceccio, Steven

    2016-11-01

    High-speed and highly loaded lifting surfaces are prone to ventilation and cavitation. Increasing use of compliant materials (e.g. composites) in such systems necessitates a better understanding of the fluid-structure interactions of lifting surfaces in multiphase flow. Experiments on a flexible surface-piercing hydrofoil have been performed in a towing tank and a free-surface cavitation tunnel. The objectives are (i) to demonstrate the effects of material compliance upon hydrodynamic performance and stability of multiphase flow regimes, and (ii) to quantify the effects of multiphase flow upon the structural response and hydroelastic stability of flexible lifting bodies. A non-optical shape-sensing method is developed, which permits 3D bending and twisting deformations of the hydrofoil to be accurately inferred. The effects of the foil's compliance on hydrodynamic loads, structural motions and flow regimes are discussed. Partial immersion of the hydrofoil causes a mode-dependent change in added-mass that can encourage coalescence of higher modes. At the same time, increasing flow speed and ventilated flow decrease the damping associated with certain modes. Unsteady cavity shedding modulates the system parameters, causing a broadening of the frequency response. The authors would like to acknowledge the support of Dr. Ki-Han Kim under ONR Grant Number N00014-13-1-0383 and N00014-16-1-2433.

  6. Optimization of cavitation venturi tube design for pico and nano bubbles generation

    Institute of Scientific and Technical Information of China (English)

    Xiong Yu; Peng Felicia⇑

    2015-01-01

    Hydrodynamic cavitaion venturi tube technique is used for pico and nano bubble generations in coal column flotation. In order to determine the optimal design of hydrodynamic cavitation venture tube for pico and nano bubble generation, a four-factor three-level Central Composite Design of Experimental was conducted for investigating four important design parameters of cavitation venturi tube governing the median size and the volume of pico and nano bubbles. The test results showed that maximum volume of pico and nano bubbles, 65–75%, and minimum mean pico and nano bubble size, 150–240 nm, were achieved at the medium ratio of the diameter of outlet of the venturi-tube and diam-eter of throat (3–4), medium outlet angle (11–13?), high inlet angle (26–27?) and high ratio of the length of the throat and the diameter of throat (2.3–3). Study the effects of the producing pico and nano bubbles on fine coal flotation was performed in a 5 cm diameter 260 cm height flotation column. The optimal percentage of pico and nano bubbles was about 70%, which produced maximum combustible material recovery of 86%with clean coal ash content of 11.7%.

  7. Sonic effervescence: A tutorial on acoustic cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Apfel, R.E. [Yale University, New Haven, Connecticut 06520-8286 (United States)

    1997-03-01

    This article on acoustic cavitation is a revision of a tutorial lecture presented at the Acoustical Society of America meeting in Austin, Texas, on 28 November 1994. The general approach adopted here differs from a review article in stressing the overarching themes that come under the category of acoustic cavitation, rather than being an encyclopedic reference on the topic. When possible, specific order-of-magnitude estimates have been given so that the reader can better understand the particular phenomena being described. The basic physics is discussed, and applications are reviewed with the goal of putting them in a useful context. {copyright} {ital 1997 Acoustical Society of America.}

  8. Dynamics of cavitating cascades. [transfer functions

    Science.gov (United States)

    Brennen, C. E.; Acosta, A. J.

    1980-01-01

    The unsteady dynamics of cavitating cascades and inducer pumps were studied with a view to understanding (and possibly predicting) the dynamic characteristics of these devices. The chronology of the research is summarized as well as the final conculsions for each task. The construction of a dynamic pump test facility and its use in making experimental measurements of the transfer function is described as well as tests conducted using a scale model of the low pressure liquid oxygen turbopump inducer in the shuttle main engine. Auto-oscillation and unsteady inlet flow characteristics are discussed in addition to blade cavity influence and bubbly cavitation.

  9. Cavitation wear resistance of engine bearing materials

    Science.gov (United States)

    Rac, Aleksandar

    1994-04-01

    The resistance to cavitation erosion of aluminum alloy, and cast and sinte-red lead-bronze, materials which are most frequently used for engine bearings, has been evaluated. The tests were carried out in motor oil at a temperature of 80 C, using a magnetostrictive vibratory tester (20 kHz). The results showed that the cavitation erosion resistance was the greatest in cast lead-bronze. On the contrary, sintered lead-bronze, though of the same chemical composition, had the greatest erosion rate. Additionally, the investigation of the overlay plated bearings showed the overlay was nonresistive to this type of wear.

  10. Hybrid reactor based on combined cavitation and ozonation: from concept to practical reality.

    Science.gov (United States)

    Gogate, P R; Mededovic-Thagard, S; McGuire, D; Chapas, G; Blackmon, J; Cathey, R

    2014-03-01

    The present work gives an in depth discussion related to the development of a hybrid advanced oxidation reactor, which can be effectively used for the treatment of various types of water. The reactor is based on the principle of intensifying degradation/disinfection using a combination of hydrodynamic cavitation, acoustic cavitation, ozone injection and electrochemical oxidation/precipitation. Theoretical studies have been presented to highlight the uniform distribution of the cavitational activity and enhanced generation of hydroxyl radicals in the cavitation zone, as well as higher turbulence in the main reactor zone. The combination of these different oxidation technologies have been shown to result in enhanced water treatment ability, which can be attributed to the enhanced generation of hydroxyl radicals, enhanced contact of ozone and contaminants, and the elimination of mass transfer resistances during electrochemical oxidation/precipitation. Compared to the use of individual approaches, the hybrid reactor is expected to intensify the treatment process by 5-20 times, depending on the application in question, which can be confirmed based on the literature illustrations. Also, the use of Ozonix® has been successfully proven while processing recycled fluids at commercial sites on over 750 oil and natural gas wells during hydraulic operations around the United States. The superiority of the hybrid process over conventional chemical treatments in terms of bacteria and scale reduction as well as increased water flowability and better chemical compatibility, which is a key requirement for oil and gas applications, has been established. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Effect of cavitation on comminution of mica powder

    Institute of Scientific and Technical Information of China (English)

    ChuwenGuo; LinshengLiu; 等

    2002-01-01

    The cavitation abrasive water jet was used in the comminution of mica.By applying a cavitation nozzle in the abrasive water jet system to enhance the effect of cavitation and friction,better comminution results were obtained.The JME-200CX transmission electron microscope was used for observing the size distribution of particles.As using cavitation abrasive water jet,the relative comminution effect is raised by more than 25% compared with using abrasive water jet oly.It can be concluded that the effect of cavitation is much more significant than that of impacting in the comminution of mica.

  12. Effect of cavitation on comminution of mica powder

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The cavitation abrasive water jet was used in the comminution of mica. By applying a cavitation nozzle in the abrasive water jet system to enhance the effect of cavitation and friction, better comminution results were obtained. The JME-200CX transmission electron microscope was used for observing the size distribution of particles. As using cavitation abrasive water jet, the relative comminution effect is raised by more than 25% compared with using abrasive water jet only. Itcan be concluded that the effect of cavitation is much more significant than that of impacting in the comminution of mica.

  13. Quasiparticle anisotropic hydrodynamics

    CERN Document Server

    Alqahtani, Mubarak

    2016-01-01

    We study an azimuthally-symmetric boost-invariant quark-gluon plasma using quasiparticle anisotropic hydrodynamics including the effects of both shear and bulk viscosities. We compare results obtained using the quasiparticle method with the standard anisotropic hydrodynamics and viscous hydrodynamics. We consider the predictions of the three methods for the differential particle spectra and mean transverse momentum. We find that the three methods agree for small shear viscosity to entropy density ratio, $\\eta/s$, but show differences at large $\\eta/s$. Additionally, we find that the standard anisotropic hydrodynamics method shows suppressed production at low transverse-momentum compared to the other two methods, and the bulk-viscous correction can drive the primordial particle spectra negative at large $p_T$ in viscous hydrodynamics.

  14. Hydrodynamics of coalescing binary neutron stars ellipsoidal treatment

    CERN Document Server

    Lai, D; Lai, Dong; Shapiro, Stu

    1994-01-01

    We employ an approximate treatment of dissipative hydrodynamics in three dimensions to study the coalescence of binary neutron stars driven by the emission of gravitational waves. The stars are modeled as compressible ellipsoids obeying a polytropic equation of state; all internal fluid velocities are assumed to be linear functions of the coordinates. The hydrodynamic equations then reduce to a set of coupled ordinary differential equations for the evolution of the principal axes of the ellipsoids, the internal velocity parameters and the binary orbital parameters. Gravitational radiation reaction and viscous dissipation are both incorporated. We set up exact initial binary equilibrium configurations and follow the transition from the quasi-static, secular decay of the orbit at large separation to the rapid dynamical evolution of the configurations just prior to contact. A hydrodynamical instability resulting from tidal interactions significantly accelerates the coalescence at small separation, leading to app...

  15. Hydrodynamics of Pumps

    OpenAIRE

    Brennen, Christopher Earls

    1994-01-01

    The subject of this monograph is the fluid dynamics of liquid turbomachines, particularly pumps. Rather than attempt a general treatise on turbomachines, we shall focus attention on those special problems and design issues associated with the flow of liquid through a rotating machine. There are two characteristics of a liquid that lead to these special problems, and cause a significantly different set of concerns than would occur in, say, a gas turbine. These are the potential for cavitation ...

  16. A compact and stable eddy covariance set-up for methane measurements using off-axis integrated cavity output spectroscopy

    Directory of Open Access Journals (Sweden)

    D. M. D. Hendriks

    2007-08-01

    Full Text Available A DLT-100 Fast Methane Analyser (FMA from Los Gatos Research (LGR Ltd. is assessed for its applicability in a closed path eddy covariance field set-up. The FMA uses off-axis integrated cavity output spectroscopy (ICOS combined with a highly specific narrow band laser for the detection of CH4 and strongly reflective mirrors to obtain a laser path length of 2×10³ to 20×10³ m. Statistical testing, a calibration experiment and comparison with high tower data showed high precision and very good stability of the instrument. The measurement cell response time was tested to be 0.10 s. In the field set-up, the FMA is attached to a scroll pump and combined with a Gill Windmaster Pro 3 axis Ultrasonic Anemometer and a Licor 7500 open path infrared gas analyzer. The power-spectra and co-spectra of the instrument are satisfactory for 10 Hz sampling rates. The correspondence with CH4 flux chamber measurements is good and the observed CH4 emissions are comparable with (eddy covariance CH4 measurements in other peat areas.

    CH4 emissions are rather variable over time and show a diurnal pattern. The average CH4 emission is 50±12.5 nmol m−2 s−1, while the typical maximum CH4 emission is 120±30 nmol m−2 s−1 (during daytime and the typical minimum flux is –20±2.5 nmol m−2 s−1 (uptake, during night time.

    Additionally, the set-up was tested for three measurement techniques with slower measurement rates, which could be used in the future to make the scroll pump superfluous and save energy. Both disjunct eddy covariance as well as slow 1 Hz eddy covariance showed results very similar to normal 10 Hz eddy covariance. Relaxed eddy accumulation (REA only matched with normal 10 Hz eddy covariance over an averaging period of at least several weeks.

  17. Set-up errors analyses in IMRT treatments for nasopharyngeal carcinoma to evaluate time trends, PTV and PRV margins

    Energy Technology Data Exchange (ETDEWEB)

    Mongioj, Valeria (Dept. of Medical Physics, Fondazione IRCCS Istituto Nazionale Tumori, Milan (Italy)), e-mail: valeria.mongioj@istitutotumori.mi.it; Orlandi, Ester (Dept. of Radiotherapy, Fondazione IRCCS Istituto Nazionale Tumori, Milan (Italy)); Palazzi, Mauro (Dept. of Radiotherapy, A.O. Niguarda Ca' Granda, Milan (Italy)) (and others)

    2011-01-15

    Introduction. The aims of this study were to analyze the systematic and random interfractional set-up errors during Intensity Modulated Radiation Therapy (IMRT) in 20 consecutive nasopharyngeal carcinoma (NPC) patients by means of Electronic Portal Images Device (EPID), to define appropriate Planning Target Volume (PTV) and Planning Risk Volume (PRV) margins, as well as to investigate set-up displacement trend as a function of time during fractionated RT course. Material and methods. Before EPID clinical implementation, an anthropomorphic phantom was shifted intentionally 5 mm to all directions and the EPIs were compared with the digitally reconstructed radiographs (DRRs) to test the system's capability to recognize displacements observed in clinical studies. Then, 578 clinical images were analyzed with a mean of 29 images for each patient. Results. Phantom data showed that the system was able to correct shifts with an accuracy of 1 mm. As regards clinical data, the estimated population systematic errors were 1.3 mm for left-right (L-R), 1 mm for superior-inferior (S-I) and 1.1 mm for anterior-posterior (A-P) directions, respectively. Population random errors were 1.3 mm, 1.5 mm and 1.3 mm for L-R, S-I and A-P directions, respectively. PTV margin was at least 3.4, 3 and 3.2 mm for L-R, S-I and A-P direction, respectively. PRV margins for brainstem and spinal cord were 2.3, 2 and 2.1 mm and 3.8, 3.5 and 3.2 mm for L-R, A-P and S-I directions, respectively. Set-up error displacements showed no significant changes as the therapy progressed (p>0.05), although displacements >3 mm were found more frequently when severe weight loss or tumor nodal shrinkage occurred. Discussion. These results enable us to choose margins that guarantee with sufficient accuracy the coverage of PTVs and organs at risk sparing. Collected data confirmed the need for a strict check of patient position reproducibility in case of anatomical changes

  18. Validation of full cavitation model in cryogenic fluids

    Institute of Scientific and Technical Information of China (English)

    CAO XiaoLi; ZHANG XiaoBin; QIU LiMin; GAN ZhiHua

    2009-01-01

    Numerical simulation of cavitation in cryogenic fluids is important in improving the stable operation of he propulsion system in liquid-fuel rocket. It also represents a broader class of problems where the fluid is operating close to its critical point and the thermal effects of cavitation are pronounced. The present article focuses on simulating cryogenic cavitation by implementing the "full cavitation model", coupled with energy equation, in conjunction with iteraUve update of the real fluid properties at local temperatures. Steady state computations are then conducted on hydrofoil and ogive in liquid nitrogen and hydrogen respectively, based on which we explore the mechanism of cavitation with thermal ef-fects. Comprehensive comparisons between the simulation results and experimental data as well as previous computations by other researchers validate the full cavitation model in cryogenic fluids. The sensitivity of cavity length to cavitation number is also examined.

  19. Effects of cavitation on performance of automotive torque converter

    Directory of Open Access Journals (Sweden)

    Jaewon Ju

    2016-06-01

    Full Text Available Cavitation is a phenomenon whereby vapor bubbles of a flowing liquid are formed in a local region where the pressure of the liquid is below its vapor pressure. It is well known that cavitation in torque converters occurs frequently when a car with an automatic transmission makes an abrupt start. Cavitation is closely related to a performance drop and noise generation at a specific operating condition in a car and a torque converter itself. This study addressed the relation between cavitation and performance in an automotive torque converter in a quantitative and qualitative manner using numerical simulations. The cavitation was calculated at various operating conditions using a commercial flow solver with the homogeneous cavitation model, and the torque converter performance was compared with the experimental data. Numerical results well match to the data and indicate that the cavitation causes significant performance drop, as the pump speed increases or both speed ratio and reference pressure decrease.

  20. Laser-nucleated acoustic cavitation in focused ultrasound.

    Science.gov (United States)

    Gerold, Bjoern; Kotopoulis, Spiros; McDougall, Craig; McGloin, David; Postema, Michiel; Prentice, Paul

    2011-04-01

    Acoustic cavitation can occur in therapeutic applications of high-amplitude focused ultrasound. Studying acoustic cavitation has been challenging, because the onset of nucleation is unpredictable. We hypothesized that acoustic cavitation can be forced to occur at a specific location using a laser to nucleate a microcavity in a pre-established ultrasound field. In this paper we describe a scientific instrument that is dedicated to this outcome, combining a focused ultrasound transducer with a pulsed laser. We present high-speed photographic observations of laser-induced cavitation and laser-nucleated acoustic cavitation, at frame rates of 0.5×10(6) frames per second, from laser pulses of energy above and below the optical breakdown threshold, respectively. Acoustic recordings demonstrated inertial cavitation can be controllably introduced to the ultrasound focus. This technique will contribute to the understanding of cavitation evolution in focused ultrasound including for potential therapeutic applications.

  1. Prevention of Pressure Oscillations in Modeling a Cavitating Acoustic Fluid

    Directory of Open Access Journals (Sweden)

    B. Klenow

    2010-01-01

    Full Text Available Cavitation effects play an important role in the UNDEX loading of a structure. For far-field UNDEX, the structural loading is affected by the formation of local and bulk cavitation regions, and the pressure pulses resulting from the closure of the cavitation regions. A common approach to numerically modeling cavitation in far-field underwater explosions is Cavitating Acoustic Finite Elements (CAFE and more recently Cavitating Acoustic Spectral Elements (CASE. Treatment of cavitation in this manner causes spurious pressure oscillations which must be treated by a numerical damping scheme. The focus of this paper is to investigate the severity of these oscillations on the structural response and a possible improvement to CAFE, based on the original Boris and Book Flux-Corrected Transport algorithm on structured meshes [6], to limit oscillations without the energy loss associated with the current damping schemes.

  2. Set-up verification and 2-dimensional electronic portal imaging device dosimetry during breath hold compared with free breathing in breast cancer radiation therapy

    NARCIS (Netherlands)

    Brouwers, Patricia J A M; Lustberg, Tim; Borger, Jacques H.; van Baardwijk, Angela A W; Jager, Jos J.; Murrer, Lars H P; Nijsten, Sebastian M J J G; Reymen, Bart H.; van Loon, Judith G M; Boersma, Liesbeth J.

    2015-01-01

    Purpose: To compare set-up and 2-dimensional (2D) electronic portal imaging device (EPID) dosimetry data of breast cancer patients treated during voluntary moderately deep inspiration breath hold (vmDIBH) and free breathing (FB). Methods and materials: Set-up data were analyzed for 29 and 51 consecu

  3. Set-up of a method using LC-UV to assay mometasone furoate in pharmaceutical dosage forms

    Directory of Open Access Journals (Sweden)

    Aline Ferreira Ourique

    2012-01-01

    Full Text Available A reliable method using LC-UV to assay mometasone furoate (MF in creams or nasal sprays using the same chromatographic conditions was set up. Methanol:water 80:20 (v/v (1.0 mL min-1 was used as mobile phase. MF was detected at 248 nm and analyzed in a concentration range from 1.0 to 20.0 µg mL-1. The method provided acceptable theoretical plates, peak simmetry, peak tailing factor and peak resolution a short run (5 min. The method showed specificity, good linearity (r = 0.9999 and the quantification limit was 0.379 µg mL-1. Furthermore, the method was precise (RSD 97% and robust.

  4. GARFIELD + RCo digital upgrade: A modern set-up for mass and charge identification of heavy-ion reaction products

    Science.gov (United States)

    Bruno, M.; Gramegna, F.; Marchi, T.; Morelli, L.; Pasquali, G.; Casini, G.; Abbondanno, U.; Baiocco, G.; Bardelli, L.; Barlini, S.; Bini, M.; Carboni, S.; Cinausero, M.; D'Agostino, M.; Degerlier, M.; Kravchuk, V. L.; Geraci, E.; Mastinu, P. F.; Ordine, A.; Piantelli, S.; Poggi, G.; Moroni, A.

    2013-10-01

    An upgraded GARFIELD + Ring Counter (RCo) apparatus is presented with improved performances as far as electronics and detectors are concerned. On the one hand fast sampling digital read out has been extended to all detectors, allowing for an important simplification of the signal processing chain together with an enriched extracted information. On the other hand a relevant improvement has been made in the forward part of the set-up (RCo): an increased granularity of the CsI(Tl) crystals and a higher homogeneity in the silicon detector resistivity. The renewed performances of the GARFIELD + RCo array make it suitable for nuclear reaction measurements both with stable and with Radioactive Ion Beams (RIB), like the ones planned for the SPES facility, where the physics of isospin can be studied.

  5. GARFIELD + RCo digital upgrade: A modern set-up for mass and charge identification of heavy-ion reaction products

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, M.; Morelli, L.; Baiocco, G.; D' Agostino, M.; Geraci, E. [INFN, Sezione di Bologna (Italy); Dipartimento di Fisica ed Astronomia dell' Universita, Bologna (Italy); Gramegna, F.; Cinausero, M.; Degerlier, M.; Kravchuk, V.L.; Mastinu, P.F. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Italy); Marchi, T. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Italy); Dipartimento di Fisica ed Astronomia dell' Universita, Padova (Italy); Pasquali, G.; Bardelli, L.; Barlini, S.; Bini, M.; Carboni, S.; Poggi, G. [INFN, Sezione di Firenze, Firenze (Italy); Dipartimento di Fisica ed Astronomia dell' Universita, Firenze (Italy); Casini, G.; Piantelli, S. [INFN, Sezione di Firenze, Firenze (Italy); Abbondanno, U. [INFN, Sezione di Trieste, Trieste (Italy); Ordine, A. [INFN, Sezione di Napoli, Napoli (Italy); Moroni, A. [INFN, Sezione di Milano, Milano (Italy)

    2013-10-15

    An upgraded GARFIELD + Ring Counter (RCo) apparatus is presented with improved performances as far as electronics and detectors are concerned. On the one hand fast sampling digital read out has been extended to all detectors, allowing for an important simplification of the signal processing chain together with an enriched extracted information. On the other hand a relevant improvement has been made in the forward part of the set-up (RCo): an increased granularity of the CsI(Tl) crystals and a higher homogeneity in the silicon detector resistivity. The renewed performances of the GARFIELD + RCo array make it suitable for nuclear reaction measurements both with stable and with Radioactive Ion Beams (RIB), like the ones planned for the SPES facility, where the physics of isospin can be studied. (orig.)

  6. Beam patterns in an optical parametric oscillator set-up employing walk-off compensating beta barium borate crystals

    Science.gov (United States)

    Kaucikas, M.; Warren, M.; Michailovas, A.; Antanavicius, R.; van Thor, J. J.

    2013-02-01

    This paper describes the investigation of an optical parametric oscillator (OPO) set-up based on two beta barium borate (BBO) crystals, where the interplay between the crystal orientations, cut angles and air dispersion substantially influenced the OPO performance, and especially the angular spectrum of the output beam. Theory suggests that if two BBO crystals are used in this type of design, they should be of different cuts. This paper aims to provide an experimental manifestation of this fact. Furthermore, it has been shown that air dispersion produces similar effects and should be taken into account. An x-ray crystallographic indexing of the crystals was performed as an independent test of the above conclusions.

  7. Report on the Working Group set up to Study the Requirements for Operating the SPS within the INB Framework (INBOPS)

    CERN Document Server

    Ball, A; Charavay, R; Elsener, K; Faugier, A; Jacot, C; Jirdén, L; Menzel, Hans Gregor; Pajunen, J; Poole, John; Roy, G; Silari, Marco; Spinks, Alan; Tsesmelis, E; Wahl, H

    2001-01-01

    The convention signed with the French authorities for the LHC defines a new Installation Nucléaire de Base (INB). The LHC machine tunnel, the experiments, some buildings which cover access shafts to the machine and the SPS with its extraction lines up to the targets are all inside the new perimeter. The new convention came into effect in September 2000 and therefore the SPS fell within the new context from that time. As a consequence, SL has to operate the SPS within this new regulatory framework and a small working group was set up to look at the requirements and to estimate the resources required. The conclusions of the working group are reported in this paper.

  8. Cavitationally induced biodegradability enhancement of a distillery wastewater.

    Science.gov (United States)

    Padoley, K V; Saharan, Virendra Kumar; Mudliar, S N; Pandey, R A; Pandit, Aniruddha B

    2012-06-15

    Hydrodynamic cavitation (HC) was evaluated as a pretreatment option for the complex/recalcitrant biomethanated distillery wastewater (B-DWW). The effect of various process parameters such as inlet pressure, dilution and reaction time on reduction of COD/TOC and enhancement of biodegradability index (BI:BOD(5):COD ratio) of the B-DWW was studied with an aim to maximize the biodegradability index and reducing the toxicity of the distillery wastewater. It was observed that higher operating pressure (13 bar) yielded the maximum BI whereas the lower pressure (5 bar) is suitable for the reduction in the toxicity of B-DWW. The toxicity of the distillery wastewater was analyzed by measuring the COD, TOC and color of the wastewater sample. The HC pretreatment under optimized conditions leads to a BI of 0.32, COD and TOC reduction of 32.24% and 31.43%, respectively along with a color reduction by 48%. These results indicate the potential of HC as a pretreatment option for enhancing the biodegradability index of the recalcitrant wastewater such as B-DWW along with reduced toxicity of wastewater as observed from COD, TOC and color reduction profile under optimized conditions.

  9. A Case of Extraordinary Dis-Set up the Radiation Controlled Area in the Reactor Building of HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sang Ik; Kim, Young Ki; Lee, Bong Jae; Jung, Hoan Sung; Lim, In Cheol [KAERI, Daejeon (Korea, Republic of)

    2010-12-15

    A special procedure for the HANARO facility has been developed to dis-set up extraordinary the some space of radiation controlled area in the reactor building which being used for 14 years after the first criticality, Feb. 1995. The procedure was intended to install the system and structures for Cold Neutron Source inside the reactor building. Because it is a very rare case in the world, there should be required to review several technical points of view. The reviewed items are following like this 1) basis to setup or dis-setup radiation controlled area, 2) maintain the physical protection for the reactor building, 3) maintain the radiation safety, 4) evaluation on the environment status of radiation and radioactivity, 5) operation procedure for the area which was temporary changed to normal, 6) maintain procedure for the confinement building, 7) maintain procedure for the radiation in working area, 8) procedure for the fire prevention, 9) evaluation on the combustible possibility for the nuclear source kept in reactor building, 10) action procedure for the emergency condition, 11) procedure to restore the changed area to the former condition. Conclusively, the developed procedure has been approved throughout the above described technical points and pre-inspection by regulatory body. By using the procedure, not only the installation of the system and structures for Cold Neutron Source has been completed on the schedule but also the amount of radioactive waste has been minimized smaller than that of the controlled area. This report proposed a case of extraordinary dis-set up the radiation controlled area in the reactor building which is being operated for long time as a nuclear facility. Not much things to be applied by this case, it would be useful for the rehabilitation or renovation work in nuclear facilities which were being operated

  10. Cavitation inception following shock wave passage

    NARCIS (Netherlands)

    Ohl, C.D.

    2002-01-01

    Cavitation bubble nucleation following the passage of an extracorporeal shock wave lithotripter pulse is investigated experimentally and numerically. In the experiments two configurations are considered: Free passage of the shock wave, and reflection of the shock wave from a rigid reflector. The nuc

  11. Classification of lubricants according to cavitation criteria

    NARCIS (Netherlands)

    Meged, Y.; Venner, C.H.; Napel, ten W.E

    1995-01-01

    Cavitation in lubrication liquids has long been known to be detrimental to components in hydraulic systems. Damage has been detected in journal bearings, especially under severe dynamic loading, gears, squeeze film dampers and valves. These findings have led to intensive studies of metal resistance

  12. The making of a cavitation children's book

    Science.gov (United States)

    Henry de Frahan, Marc; Patterson, Brandon; Lazar, Erika

    2016-11-01

    Engaging young children in science is particularly important to future scientific endeavors. From thunderstorms to the waterpark, children are constantly exposed to the wonders of fluid dynamics. Among fluid phenomena, bubbles have always fascinated children. Yet some of the most exciting aspects of bubbles, such as cavitation, are scarcely known to non-experts. To introduce cavitation to a five year old audience, we wrote "Brooke Bubble Breaks Things", a children's book about the adventures of a cavitation bubble learning about all the things she could break. In this talk, we discuss how a children's book is made by walking through the steps involved in creating the book from concept to publication. We focus on strategies for successfully communicating a technical message while balancing entertainment and fidelity to nature. To provide parents, teachers, and young inquiring minds with a detailed explanation of the physics and applications of cavitation, we also created a website with detailed explanations, animations, and links to further information. We aim to convince the fluids community that writing picture books is an intellectually stimulating and fun way of communicating fluids principles and applications to children. ArtsEngine Microgrant at the University of Michigan.

  13. On cavitation instabilities with interacting voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2012-01-01

    voids so far apart that the radius of the plastic zone around each void is less than 1% of the current spacing between the voids, can still affect each others at the occurrence of a cavitation instability such that one void stops growing while the other grows in an unstable manner. On the other hand...

  14. Cavitation inception following shock wave passage

    NARCIS (Netherlands)

    Ohl, C.D.

    2002-01-01

    Cavitation bubble nucleation following the passage of an extracorporeal shock wave lithotripter pulse is investigated experimentally and numerically. In the experiments two configurations are considered: Free passage of the shock wave, and reflection of the shock wave from a rigid reflector. The nuc

  15. Cavitation of a Physically Associating Gel

    Science.gov (United States)

    Mishra, Satish; Kundu, Santanu

    Self-assembly of block copolymers in selective solvents form ordered structures such as micelles, vesicles, and physically crosslinked gels due to difference in their interaction with solvents. These gels have wide range of applications in tissue engineering, food science and biomedical field due to their tunable properties and responsiveness with changing environmental conditions. Pressurization of a defect inside a physically associating gel can lead to elastic instability (cavitation) leading to failure of the gel. The failure behavior involves dissociation of physical networks. A thermoreversible, physically associating gel with different volume fractions of a triblock copolymer, poly (methyl methacrylate)-poly (n-butyl acrylate)-poly (methyl methacrylate) [PMMA-PnBA-PMMA] in 2-ethyl 1-hexanol, a midblock selective solvent, is considered here. Mechanical properties were investigated using shear rheology and cavitation experiments. The experimental data is fitted with a constitutive model that captures the stiffening behavior followed by softening behavior of a physical gel. Finite element analysis has been performed on cavitation rheology geometry to capture the failure behavior and to calculate energy release rate during cavitation experiments.

  16. Modeling of Cavitating Flow through Waterjet Propulsors

    Science.gov (United States)

    2015-02-18

    break down due to massive suction side flow separation (stall). In Figure 3, photographs from tunnel testing and computed results are shown. The...128, pp. 1308-1323. Mishra C. & Peles, Y. (2005) "Cavitation in flow through a micro- orifice inside a silicon micro- channel,’ Phvs. Fluids 17

  17. Measuring cavitation and its cleaning effect

    NARCIS (Netherlands)

    Verhaagen, Bram; Fernandez Rivas, David

    2016-01-01

    The advantages and limitations of techniques for measuring the presence and amount of cavitation, and for quantifying the removal of contaminants, are provided. After reviewing chemical, physical, and biological studies, a universal cause for the cleaning effects of bubbles cannot yet be concluded.

  18. Ultrasound induced by CW laser cavitation bubbles

    Energy Technology Data Exchange (ETDEWEB)

    Korneev, N; Montero, P Rodriguez; Ramos-Garcia, R; Ramirez-San-Juan, J C; Padilla-Martinez, J P, E-mail: korneev@inaoep.mx [Instituto Nacional de Astrofisica, Optica y Electronica, Apt. Postal 51 y 216 CP72000, Puebla, Pue. (Mexico)

    2011-01-01

    The generation of ultrasound by a collapsing single cavitation bubble in a strongly absorbing liquid illuminated with a moderate power CW laser is described. The ultrasound shock wave is detected with hydrophone and interferometric device. To obtain a stronger pulse it is necessary to adjust a liquid absorption and a beam diameter. Their influence can be qualitatively understood with a simple model.

  19. Modelling cavitating flow around underwater missiles

    Directory of Open Access Journals (Sweden)

    Fabien Petitpas

    2011-12-01

    Full Text Available The diffuse interface model of Saurel et al. (2008 is used for the computation of compressible cavitating flows around underwater missiles. Such systems use gas injection and natural cavitation to reduce drag effects. Consequently material interfaces appear separating liquid and gas. These interfaces may have a really complex dynamics such that only a few formulations are able to predict their evolution. Contrarily to front tracking or interface reconstruction method the interfaces are computed as diffused numerical zones, that are captured in a routinely manner, as is done usually with gas dynamics solvers for shocks and contact discontinuity. With the present approach, a single set of partial differential equations is solved everywhere, with a single numerical scheme. This leads to very efficient solvers. The algorithm derived in Saurel et al. (2009 is used to compute cavitation pockets around solid bodies. It is first validated against experiments done in cavitation tunnel at CNU. Then it is used to compute flows around high speed underwater systems (Shkval-like missile. Performance data are then computed showing method ability to predict forces acting on the system.

  20. Control of Propeller Cavitation in Operational Conditions

    NARCIS (Netherlands)

    Vrijdag, A.

    2009-01-01

    Off design conditions can have a severe impact on ship propulsion system behaviour. Resistance increase for instance leads to a higher engine loading, and can also easily lead to a decrease of cavitation inception speed with respect to calm water conditions. Wakefield variations due to ship motions,

  1. Cavitation for improved sludge conversion into biogas

    NARCIS (Netherlands)

    Stoop, A.H.; Bakker, T.W.; Kramer, H.J.M.

    2015-01-01

    In several studies the beneficial influence of pre-treatment of waste activated sludge with cavitation on the biogas production was demonstrated. It is however, still not fully certain whether this effect should be mainly contributed to an increase in conversion rate of organics into biogas by anaer

  2. On some hydrodynamical aspects of quantum mechanics

    CERN Document Server

    Spera, Mauro

    2009-01-01

    In this note we first set up an analogy between spin and vorticity of a perfect 2d-fluid flow, based on the Borel-Weil contruction of the irreducible unitary representations of SU(2), and looking at the Madelung-Bohm velocity attached to the ensuing spin wave functions. We also show that, in the framework of finite dimensional geometric quantum mechanics, the Schr\\"odinger velocity field on projective Hilbert space is divergence-free (being Killing with respect to the Fubini-Study metric) and fulfils the stationary Euler equation, with pressure proportional to the Hamiltonian uncertainty (squared). We explicitly compute the pressure gradient of this "Schr\\"odinger fluid" and determine its critical points. Its vorticity is also calculated and shown to depend on the spacings of the energy levels. These results follow from hydrodynamical properties of Killing vector fields valid in any (finite dimensional) Riemannian manifold, of possible independent interest.

  3. On some hydrodynamical aspects of quantum mechanics

    Science.gov (United States)

    Spera, Mauro

    2010-02-01

    In this note we first set up an analogy between spin and vorticity of a perfect 2d-fluid flow, based on the complex polynomial (i.e. Borel-Weil) realization of the irreducible unitary representations of SU(2), and looking at the Madelung-Bohm velocity attached to the ensuing spin wave functions. We also show that, in the framework of finite dimensional geometric quantum mechanics, the Schrödinger velocity field on projective Hilbert space is divergence-free (being Killing with respect to the Fubini-Study metric) and fulfils the stationary Euler equation, with pressure proportional to the Hamiltonian uncertainty (squared). We explicitly determine the critical points of the pressure of this "Schrödinger fluid", together with its vorticity, which turns out to depend on the spacings of the energy levels. These results follow from hydrodynamical properties of Killing vector fields valid in any (finite dimensional) Riemannian manifold, of possible independent interest.

  4. Hydrodynamics and black holes

    CERN Document Server

    Oz, Yaron

    2015-01-01

    This chapter describes how the AdS/CFT correspondence (the Holographic Principle) relates field theory hydrodynamics to perturbations of black hole (brane) gravitational backgrounds. The hydrodynamics framework is first presented from the field theory point of view, after which the dual gravitational description is outlined, first for relativistic fluids and then for the nonrelativistic case. Further details of the fluid/gravity correspondence are then discussed, including the bulk geometry and the dynamics of the black hole horizon.

  5. Detection of actinides and rare earths in natural matrices with the AGLAE new, high sensitivity detection set-up

    Science.gov (United States)

    Zucchiatti, Alessandro; Alonso, Ursula; Lemasson, Quentin; Missana, Tiziana; Moignard, Brice; Pacheco, Claire; Pichon, Laurent; Camarena de la Mora, Sandra

    2014-08-01

    A series of granite samples (Grimsel and Äspö) enriched by sorption with natU (10-3 M, 10-4 M, 10-5 M in solution) and La (10-3 M, 10-4 M in solution) has been scanned by PIXE over a surface of 1920 × 1920 mm2 together with non-enriched Grimsel and Äspö granites and a glass standard. An assessment of minimum detection limits, MDL's, for several elements has been performed with the use of standard materials. Due to mapping and the high sensitivity of the new AGLAE detection system, U levels around 30 ppm can be detected from the whole PIXE spectrum (one low energy detector and four summed filtered detectors) while U reach grains, inhomogeneously distributed over the surface can be clearly identified through the multi elemental maps and analyzed separately. Even the nominally enriched samples have La levels below the MDL, probably because precipitation of the element (and not adsorption) mostly took place, and precipitates were eliminated after surface cleaning carried out before PIXE analyses. A multi detector system that implies a PIXE detection solid angle much wider than in any other similar set-up (a factor of 2-5); a higher events selectivity, given by the possibility of filtering individually up to 4 PIXE detectors; a double RBS detector, the new Ion Beam Induced Luminescence (IBIL) spectrometry and gamma spectrometry. Full mapping capability in air, assisted by a powerful event by event reconstruction software. These features allow lower Minimum Detection Limits (MDL) which are highly beneficial to the analysis of cultural heritage objects, meaning generally a reduction of irradiation time. Paintings will then be studied without any damage to the pigments that have color change tendencies which is a major drawback of the previous system. Alternatively they could allow an increase in information collected at equal time, particularly considering the detector's fast response and therefore the potential for high beam currents when sample damage can be

  6. PENERAPAN METODE JUST-IN-TIME DENGAN PEMBAKUAN KEGIATAN DAN MINIMASI WAKTU SET-UP PADA BAGIAN PERMESINAN PEMBUATAN PRODUK GT 060

    Directory of Open Access Journals (Sweden)

    Indah Pratiwi

    2007-08-01

    Full Text Available Membuat produk dalam jumlah banyak menyebabkan pemborosan yang dapat mengurangi efisiensi produksi. Aktivitas yang paling banyak membuang waktu adalah aktivitas set-up mesin, untuk mengatasi masalah ini maka perlu diterapkan metode just-in-time dengan pembakuan kegiatan dan minimasi waktu set-up dengan mengambil kondisi real yang ada pada lantai produksi. Penelitian dilakukan di CV. Roda Jati, data yang digunakan adalah waktu penyelesaian komponen frame ujung produk GT 060 pada bagian permesinan dan waktu set-up mesin. Analisa meliputi : urutan kegiatan sekarang, usulan pembakuan kegiatan, perbaikan pembakuan kegiatan menggunakan minimasi waktu set-up, analisa menggunakan prinsip 5S. Hasil dari pengamatan didapatkan pembakuan kegiatan pada bagian permesinan dan mengurangi waktu set-up mesin. Waktu yang digunakan untuk memproduksi komponen tersebut sebelum dilakukan pembakuan kegiatan sebesar 4655,42 detik dan mengalami penurunan menjadi 4635,08 detik. Setelah dilakukan minimasi waktu set-up maka mengalami penurunan lagi mejadi sebesar 4296,31detik. Agar proses dapat selesai tepat waktu maka operator harus mentaati kegiatan yang telah dibakukan perusahaan dan dilakukan minimasi waktu set-up sebelum melakukan pekerjaan. Mempromosikan program 5S agar pekerja membiasakan diri untuk menjaga kerapian, kebersihan dan kedisplinan pada waktu berkerja.

  7. A compact and stable eddy covariance set-up for methane measurements using off-axis integrated cavity output spectroscopy

    Directory of Open Access Journals (Sweden)

    D. M. D. Hendriks

    2008-01-01

    Full Text Available A Fast Methane Analyzer (FMA is assessed for its applicability in a closed path eddy covariance field set-up in a peat meadow. The FMA uses off-axis integrated cavity output spectroscopy combined with a highly specific narrow band laser for the detection of CH4 and strongly reflective mirrors to obtain a laser path length of 2–20×103 m. Statistical testing and a calibration experiment showed high precision (7.8×10−3 ppb and accuracy (<0.30% of the instrument, while no drift was observed. The instrument response time was determined to be 0.10 s. In the field set-up, the FMA is attached to a scroll pump and combined with a 3-axis ultrasonic anemometer and an open path infrared gas analyzer for measurements of carbon dioxide and water vapour. The power-spectra and co-spectra of the instruments were satisfactory for 10 Hz sampling rates.

    Due to erroneous measurements, spikes and periods of low turbulence the data series consisted for 26% of gaps. Observed CH4 fluxes consisted mainly of emission, showed a diurnal cycle, but were rather variable over. The average CH4 emission was 29.7 nmol m−2 s−1, while the typical maximum CH4 emission was approximately 80.0 nmol m−2 s−1 and the typical minimum flux was approximately 0.0 nmol m−2 s−1. The correspondence of the measurements with flux chamber measurements in the footprint was good and the observed CH4 emission rates were comparable with eddy covariance CH4 measurements in other peat areas.

    Additionally, three measurement techniques with lower sampling frequencies were simulated, which might give the possibility to measure CH4 fluxes without an external pump and save energy. Disjunct eddy covariance appeared to be the most reliable substitute for 10 Hz eddy covariance, while relaxed eddy accumulation gave

  8. Investigation of Two-Phase Flow in AxialCentrifugal Impeller by Hydrodynamic Modeling Methods

    Directory of Open Access Journals (Sweden)

    V. O. Lomakin

    2014-01-01

    Full Text Available The article provides a methodology to study the flow in the wet part of the pump with fundamentally new axial-centrifugal impeller by methods of hydrodynamic modeling in the software package STAR CCM +. The objective of the study was to determine the normal and cavitation characteristics of the pump with a new type of wet part, as well as optimization of the geometrical parameters of the pump. Authors solved this problem using an example of the hot coolant pump, which should meet high requirements for cavitation quality and efficiency (hydraulic efficiency up to 87%, critical value of NPSH to 2.2 m.Also, the article focuses on the methods of numerical solution of two-phase flow simulation in a pump that are needed for a more accurate simulation of cavitation in the pump and research work in liquids with high gas content.Hydrodynamic modeling was performed on a computing cluster at the department E-10 of BMSTU for pump flow simulation in unsteady statement of problem using the computational grid size to 1.5 million cells. Simultaneously, the experimental model of the pump was made by 3D printing and tested at the stand in the BMSTU. Test results, which were compared with the calculated data are also given in the article. Inaccuracy of the calculation of pump head does not exceed 5%.The simulation results may be of interest to specialists in the field of hydrodynamic modeling, and for designers of such pumps. The authors also report production of a full-length prototype of the pump in order to conduct further testing for the verification of the data in the article, primarily in terms of cavitation characteristics.

  9. Development of a full scale remote steerable ECRH mm-wave launching system test set-up for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Elzendoorn, B.S.Q. [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, Nieuwegein, Edisonbaan 14, 3439 MN Nieuwegein (Netherlands)], E-mail: ben@rijnh.nl; Bongers, W.A.; Graswinckel, M.F. [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, Nieuwegein, Edisonbaan 14, 3439 MN Nieuwegein (Netherlands); Jamar, J. [TNO Science and Industry, Business Unit Design and Manufacturing, Eindhoven, P.O. Box 6235, 5600 HE Eindhoven (Netherlands); Kruijt, O.G.; Lamers, B.; Ronden, D.M.S. [FOM Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, Nieuwegein, Edisonbaan 14, 3439 MN Nieuwegein (Netherlands); Verhoeven, A.G.A

    2007-10-15

    FOM is developing a full-scale mock-up of the mm-wave upper-port launching system for electron cyclotron resonance heating in ITER. The test set-up foresees in most of the typical ITER operation conditions, e.g. primary vacuum and the secondary vacuum, blanket cooling and component cooling conditions. All relevant operational ITER conditions except neutron radiation can be simulated, including baking conditions. The fabrication of the launching system mock-up will be the last step in the development phase, which will be characterized by the fabrication of test samples and mm-wave tests and calculations. The parameterized modeling of mm-wave beam propagation in CATIA [D.M.S. Ronden, et al., Parameterized modeling of mm-wave beam propagation of the ITER ECRH remote steering upper port launcher in CATIA, this conference] (8th figure in this article) the test and calculation results will be used for the built to print design of the remote steering ECRH launcher for the ITER upper ports [A.G.A. Verhoeven, et al., Design of the Remote Steering ITER ECRH Upper Port Launcher, this conference].

  10. Set-up and first operation of a plasma oven for treatment of low level radioactive wastes

    Directory of Open Access Journals (Sweden)

    Nachtrodt Frederik

    2014-01-01

    Full Text Available An experimental device for plasma treatment of low and intermediate level radioactive waste was built and tested in several design variations. The laboratory device is designed with the intention to study the general effects and difficulties in a plasma incineration set-up for the further future development of a larger scale pilot plant. The key part of the device consists of a novel microwave plasma torch driven by 200 W electric power, and operating at atmospheric pressure. It is a specific design characteristic of the torch that a high peak temperature can be reached with a low power input compared to other plasma torches. Experiments have been carried out to analyze the effect of the plasma on materials typical for operational low-level wastes. In some preliminary cold tests the behavior of stable volatile species e. g., caesium was investigated by TXRF measurements of material collected from the oven walls and the filtered off-gas. The results help in improving and scaling up the existing design and in understanding the effects for a pilot plant, especially for the off-gas collection and treatment.

  11. TWINNING between Institutions in developed and less developed countries: an ideal way to set-up an astrophysics program

    Science.gov (United States)

    Carignan, Claude

    2015-03-01

    It is very difficult to start from scratch a new Astrophysics program in a country with very little or no researchers in the field. In 2007, we began to set-up an Astrophysics program by TWINNING the Université de Ouagadougou with the Université de Montréal in Canada, the Université de Provence in France and the University of Cape Town in South Africa. Already, courses are given at the undergraduate and Master levels and a teaching Observatory has been built. A 1m research telescope was also moved from the La Silla Observatory in Chile to Burkina Faso and the infrastructure is being built at the moment on mount Djaogari in the north-eastern part of the country. In the meantime, 6 students are doing their PhD in Astrophysics overseas (Canada, France and South Africa) and will become the core of the research group at the Université de Ouagadougou. An engineer is also doing his PhD in Astronomical Instrumentation to help with the maintenance of the equipment on the Research Telescope.

  12. Material Independent Long Distance Pulling, Trapping, and Rotation of Fully Immersed Multiple Objects with a Single Optical Set-up

    CERN Document Server

    Rahman, Md Masudur; Mahdy, Mahdy Rahman Chowdhury; Haque, Md Ehsanul; Islam, Rakibul; Chowdhury, S Tanvir-ur-Rahman; Nieto-Vesperinas, Manuel; Matin, Md Abdul

    2015-01-01

    Optical pulling with tractor beams is so far highly dependent on (i) the property of embedding background or the particle itself , (ii) the number of the particles and/or (iii) the manual ramping of beam phase. A necessary theoretical solution of these problems is proposed here. This article demonstrates a novel active tractor beam for multiple fully immersed objects with its additional abilities of yielding a controlled rotation and a desired 3D trapping. Continuous and stable long distance levitation, controlled rotation and 3D trapping are demonstrated with a single optical set-up by using two coaxial, or even non-coaxial, superimposed non-diffracting higher order Bessel beams of reverse helical nature and different frequencies. The superimposed beam has periodic intensity variations both along and around the beam-axis because of the difference in longitudinal wave-vectors and beam orders, respectively. The difference in frequencies of two laser beams makes the intensity pattern move along and around the b...

  13. Social and cultural resources for the setting up and functioning of family enterprises in a small Bulgarian town

    Directory of Open Access Journals (Sweden)

    Petrova Ivanka

    2015-01-01

    Full Text Available As a field of culture, the family enterprise shows that in the current European societies the economic operation does not proceed only from a purely rational point of view and that notwithstanding the common speaking of globalization, the local may be a prerequisite for successful economic development. My objective has been to show, proceeding from an example from a small Bulgarian town, that the family enterprise is a field of culture in which the observed phenomena are strongly influenced by the social inclusion of the enterprise and by its tie-up with the context of the urban environment. I shall investigate in what way local social and cultural resources are intensively used in the process of setting up and functioning of a family enterprise from the sphere of hoteldom and tourism in the town of Belogradchik. I intend to study whether these resources are conducive to the economic prosperity of the firm. Another research objective is to establish the manner of identification of the enterprise with the town, with the region and the local culture by way of the services provided (tourist and restaurant. I shall look for an answer to the question of how the enterprise’ working realm fits in the concrete cultural, historical and social context of the town.

  14. Association between reproductive factors and breast cancer in an urban set up at central India: A case-control study

    Directory of Open Access Journals (Sweden)

    R Lodha

    2011-01-01

    Full Text Available Background: Epigenetic changes, geography and environmental factors do surpass the genetic factors in the development of breast cancer. This study investigates the association of reproductive factors with the breast cancer in this context. Objective: To detect the association of reproductive risk factors with breast cancer in an urban set up at central India. Study Design: Matched paired community-based case-control study. Materials and Methods: The study was conducted for a period of a year from October 2008 to August 2009 in Bhopal (MP. Demographic data and reproductive risk factor related information were collected using structured questionnaire. Data analysis was done by Epi-info and SPSS 16. Results: History of using oral contraceptive pills (OR = 3.02, 95% CI: 1.28-7.11, history of not having breastfeeding (OR = 3.62, 95% CI: 1.29-10.16 and family history of breast cancer (OR = 3.98, 95%CI: 1.06-14.826 were associated significantly with the occurrence of breast cancer in multivariate analysis. Conclusions: The findings of the present study suggests that positive family history of breast cancer and history of using OCP may be the epigenetic factors promoting the occurrence of breast cancer while breastfeeding reduces the possibility of acquiring breast cancer.

  15. The upgraded external-beam PIXE/PIGE set-up at LABEC for very fast measurements on aerosol samples

    Science.gov (United States)

    Lucarelli, F.; Calzolai, G.; Chiari, M.; Giannoni, M.; Mochi, D.; Nava, S.; Carraresi, L.

    2014-01-01

    At the 3 MV Tandetron accelerator of the LABEC laboratory of INFN in Florence, an external beam facility is fully dedicated to measurements of elemental composition of atmospheric aerosol. The experimental set-up hitherto used for this kind of applications has been upgraded with the replacement of a traditional Si(Li) detector for the detection of medium-high Z elements with a silicon drift detector (SDD) with a big active area (80 mm2) and 450 μm thickness, with the aim of obtaining better minimum detection limits (MDL) and reduce measuring times. The Upilex extraction window has been replaced by a more resistant one (Si3N4). A comparison between the old Si(Li) and the new SDD for aerosol samples collected on different substrata like Teflon, Kapton and Nuclepore evidenced the better performances of the SDD. It allows obtaining better results (higher counting statistics, lower MDLs) even in shorter measuring times, thus allowing very fast analysis of both daily and hourly samples.

  16. The upgraded external-beam PIXE/PIGE set-up at LABEC for very fast measurements on aerosol samples

    Energy Technology Data Exchange (ETDEWEB)

    Lucarelli, F., E-mail: lucarelli@fi.infn.it; Calzolai, G.; Chiari, M.; Giannoni, M.; Mochi, D.; Nava, S.; Carraresi, L.

    2014-01-01

    At the 3 MV Tandetron accelerator of the LABEC laboratory of INFN in Florence, an external beam facility is fully dedicated to measurements of elemental composition of atmospheric aerosol. The experimental set-up hitherto used for this kind of applications has been upgraded with the replacement of a traditional Si(Li) detector for the detection of medium–high Z elements with a silicon drift detector (SDD) with a big active area (80 mm{sup 2}) and 450 μm thickness, with the aim of obtaining better minimum detection limits (MDL) and reduce measuring times. The Upilex extraction window has been replaced by a more resistant one (Si{sub 3}N{sub 4}). A comparison between the old Si(Li) and the new SDD for aerosol samples collected on different substrata like Teflon, Kapton and Nuclepore evidenced the better performances of the SDD. It allows obtaining better results (higher counting statistics, lower MDLs) even in shorter measuring times, thus allowing very fast analysis of both daily and hourly samples.

  17. Linking mathematics with engineering applications at an early stage - implementation, experimental set-up and evaluation of a pilot project

    Science.gov (United States)

    Rooch, Aeneas; Junker, Philipp; Härterich, Jörg; Hackl, Klaus

    2016-03-01

    Too difficult, too abstract, too theoretical - many first-year engineering students complain about their mathematics courses. The project MathePraxis aims to resolve this disaffection. It links mathematical methods as they are taught in the first semesters with practical problems from engineering applications - and thereby shall give first-year engineering students a vivid and convincing impression of where they will need mathematics in their later working life. But since real applications usually require more than basic mathematics and first-year engineering students typically are not experienced with construction, mensuration and the use of engineering software, such an approach is hard to realise. In this article, we show that it is possible. We report on the implementation of MathePraxis at Ruhr-Universität Bochum. We describe the set-up and the implementation of a course on designing a mass damper which combines basic mathematical techniques with an impressive experiment. In an accompanying evaluation, we have examined the students' motivation relating to mathematics. This opens up new perspectives how to address the need for a more practically oriented mathematical education in engineering sciences.

  18. Novel Set-Up for Low-Disturbance Sampling of Volatile and Non-volatile Compounds from Plant Roots.

    Science.gov (United States)

    Eilers, Elisabeth J; Pauls, Gerhard; Rillig, Matthias C; Hansson, Bill S; Hilker, Monika; Reinecke, Andreas

    2015-03-01

    Most studies on rhizosphere chemicals are carried out in substrate-free set-ups or in artificial substrates using sampling methods that require an air flow and may thus cause disturbance to the rhizosphere. Our study aimed to develop a simplified and inexpensive system that allows analysis of rhizosphere chemicals at experimentally less disturbed conditions. We designed a mesocosm in which volatile rhizosphere chemicals were sampled passively (by diffusion) without air- and water flow on polydimethylsiloxane-(PDMS) tubes. Dandelion (Taraxacum sect. ruderalia) was used as model plant; roots were left undamaged. Fifteen volatiles were retrieved from the sorptive material by thermal desorption for analysis by gas chromatography/mass spectrometry (GC/MS). Furthermore, three sugars were collected from the rhizosphere substrate by aqueous extraction and derivatized prior to GC/MS analysis. In order to study how the quantity of detected rhizosphere compounds depends on the type of soil or substrate, we determined the matrix-dependent recovery of synthetic rhizosphere chemicals. Furthermore, we compared sorption of volatiles on PDMS tubes with and without direct contact to the substrate. The results show that the newly designed mesocosm is suitable for low-invasive extraction of volatile and non-volatile compounds from rhizospheres. We further highlight how strongly the type of substrate and contact of PDMS tubes to the substrate affect the detectability of compounds from rhizospheres.

  19. Computational Analyses of Cavitating Flows in Cryogenic Liquid Hydrogen

    Institute of Scientific and Technical Information of China (English)

    Tiezhi Sun; Yingjie Wei; Cong Wang∗

    2016-01-01

    The objective of this study is to analyze the fundamental characteristics and the thermodynamic effects of cavitating flows in liquid hydrogen. For this purpose, numerical simulation of cavitating flows are conducted over a three dimensional hydrofoil in liquid hydrogen. Firstly, the efficiency of this computational methodology is validated through comparing the simulation results with the experimental measurements of pressure and temperature. Secondly, after analysing the cavitating flows in liquid hydrogen and water, the characteristics under cryogenic conditions are highlighted. The results show that the thermodynamic effects play a significant role in the cavity structure and the mass transfer, the dimensionless mass transfer rate of liquid hydrogen is much larger, and the peak value is about ninety times as high as water at room temperature. Furthermore, a parametric study of cavitating flows on hydrofoil is conducted by considering different cavitation number and dimensionless thermodynamic coefficient. The obtained results provide an insight into the thermodynamic effect on the cavitating flows.

  20. U-shaped Vortex Structures in Large Scale Cloud Cavitation

    Science.gov (United States)

    Cao, Yantao; Peng, Xiaoxing; Xu, Lianghao; Hong, Fangwen

    2015-12-01

    The control of cloud cavitation, especially large scale cloud cavitation(LSCC), is always a hot issue in the field of cavitation research. However, there has been little knowledge on the evolution of cloud cavitation since it is associated with turbulence and vortex flow. In this article, the structure of cloud cavitation shed by sheet cavitation around different hydrofoils and a wedge were observed in detail with high speed camera (HSC). It was found that the U-shaped vortex structures always existed in the development process of LSCC. The results indicated that LSCC evolution was related to this kind of vortex structures, and it may be a universal character for LSCC. Then vortex strength of U-shaped vortex structures in a cycle was analyzed with numerical results.

  1. Comminution of Mica by Cavitation Abrasive Water Jet

    Institute of Scientific and Technical Information of China (English)

    GUO Chu-wen; LIU Lin-sheng; HAN Dong-tai; LI Ai-min; ZHANG Dong-hai

    2003-01-01

    The comminution of mica with an abrasive water jet is mainly based on three knids of effects, that is, high-speed collision, cavitating effect and shearing effect. Cavitation abrasive water jet was applied for the comminution of mica because cavitation abrasive water jet can make full use of the three effects mentioned above. Besides high speed impacting among particles,cavitation and shearing were also enhanced due to the divergent angle at the outlet of the cavitation nozzle.A JME-200CX transmission electron microscope was used for observing the size distribution of particles.Variance analysis on the experimental results indicates that the effect of cavitation is much more significant than that of collision.The effect of pressure on comminution results becomes less with the decrease of the particle size.

  2. Cavitation erosion behavior of nickel-aluminum bronze weldment

    Institute of Scientific and Technical Information of China (English)

    李小亚; 闫永贵; 许振明; 李建国

    2003-01-01

    Cavitation erosion behavior of nickel-aluminum bronze(NAB)weldment in 3.5% NaCl aqueous solution was studied by magnetostrictive vibratory device for cavitation erosion.The results show that cavitation erosion resistance of the weld zone(WZ)of the weldment is superior to that of the base metal.SEM observation of eroded specimens reveals that the phases undergoing selective attack by the stress of cavitation erosion at the early stage of cavitation erosion are:martensite in the WZ,α phase in the heat-affected zone(HAZ)and eutectoidal phase in the base metal; the microcracks causing cavitation damage initiate at the phase boundaries.

  3. Cavitation measurement during sonic and ultrasonic activated irrigation.

    Science.gov (United States)

    Macedo, Ricardo; Verhaagen, Bram; Rivas, David Fernandez; Versluis, Michel; Wesselink, Paul; van der Sluis, Luc

    2014-04-01

    The aims of this study were to quantify and to visualize the possible occurrence of transient cavitation (bubble formation and implosion) during sonic and ultrasonic (UAI) activated irrigation. The amount of cavitation generated around several endodontic instruments was measured by sonochemiluminescence dosimetry inside 4 root canal models of human dimensions and varying complexity. Furthermore, the spatial distribution of the sonochemiluminescence in the root canal was visualized with long-exposure photography. Instrument oscillation frequency, ultrasonic power, and file taper influenced the occurrence and amount of cavitation. In UAI, cavitation was distributed between the file and the wall extending beyond the file and inside lateral canals/isthmuses. In sonic activated irrigation, no cavitation was detected. Cavitation was shown to occur in UAI at clinically relevant ultrasonic power settings in both straight and curved canals but not around sonically oscillating instruments, driven at their highest frequency. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Detached eddy simulation of unsteady cavitation and pressure fluctuation around 3-D NACA66 hydrofoil

    Directory of Open Access Journals (Sweden)

    Zhang De-Sheng

    2015-01-01

    Full Text Available The unsteady cavitating flow and pressure fluctuation around the 3-D NACA66 hydrofoil were simulated and validated based on detached eddy simulation turbulence model and a homogeneous cavitation model. Numerical results show that detached eddy simulation can predict the evolution of cavity inception, sheet cavitation growth, cloud cavitation shedding, and breakup, as well as the pressure fluctuation on the surface of hydrofoil. The sheet cavitation growth, detachment, cloud cavitation shedding are responsible for the features of the pressure fluctuation.

  5. Time-evolving statistics of cavitation damage on metallic surfaces.

    Science.gov (United States)

    Diodati, P; Marchesoni, F

    2002-11-01

    The statistics of surface damage on polycrystalline aluminium plates caused by acoustic cavitation is studied experimentally as a function of time. Cavitation is shown to produce a uniform distribution of crater-like holes with different depth, area and eccentricity. Most notably, the size distribution of such craters evolves with time from a gamma function into a power law. By contrast, on the surface of a martensitic Cu-Ni-Al crystal cavitation damage generates ramified patterns, reminiscent of a fractal object.

  6. L-Area Cavitation Tests Final Analysis - Limits Application

    Energy Technology Data Exchange (ETDEWEB)

    Wood, D.C.

    2001-06-26

    The L-Area cavitation test was designed to better define the onset of cavitation in the reactor system. The onset of gas evolution in the effluent piping and pump cavitation was measured using state-of-the-art equipment to provide data with a high confidence and low uncertainty level. The limits calculated from the new data will allow an approximate two percent increase in reactor power if the reactor is effluent temperature-limited with no compromise in reactor safety.

  7. A comparative study of set up variations and bowel volumes in supine versus prone positions of patients treated with external beam radiation for carcinoma rectum

    Directory of Open Access Journals (Sweden)

    K R Rajeev

    2014-01-01

    Conclusion: The prone position using BB device was more effective in reducing irradiated SB volume in rectal cancer patients. There were no significant variations in the daily set up for patients treated in both supine and prone positions.

  8. Preparation of graphene by jet cavitation

    Science.gov (United States)

    Shen, Zhigang; Li, Jinzhi; Yi, Min; Zhang, Xiaojing; Ma, Shulin

    2011-09-01

    Despite its bright prospects, graphene faces challenges including issues concerning mass production. Here we present a totally green approach whereby common crystal graphite can be exfoliated into graphene sheets in aqueous solution by jet cavitation. This is possible mainly because the tensile stress caused by graphite-solution interfacial reflection of compressive waves acts an intensive 'suction disk' on the graphite flakes. We confirm the presence of graphene sheets by diverse characterizations. The graphene yield by our method is estimated as ~ 4 wt%, which could potentially be improved by further processing. The method, of a mechanical nature, is powerful compared to the traditional low-throughput micromechanical cleavage. Our work here illustrates jet cavitation as a facile, low cost, timesaving and laborsaving route, which can potentially be scaled up to mass production of graphene.

  9. Cavitation-based hydro-fracturing simulator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John; Wang, Hong; Ren, Fei; Cox, Thomas S.

    2016-11-22

    An apparatus 300 for simulating a pulsed pressure induced cavitation technique (PPCT) from a pressurized working fluid (F) provides laboratory research and development for enhanced geothermal systems (EGS), oil, and gas wells. A pump 304 is configured to deliver a pressurized working fluid (F) to a control valve 306, which produces a pulsed pressure wave in a test chamber 308. The pulsed pressure wave parameters are defined by the pump 304 pressure and control valve 306 cycle rate. When a working fluid (F) and a rock specimen 312 are included in the apparatus, the pulsed pressure wave causes cavitation to occur at the surface of the specimen 312, thus initiating an extensive network of fracturing surfaces and micro fissures, which are examined by researchers.

  10. Cavitated Bifurcation for Incompressible Hyperelastic Material

    Institute of Scientific and Technical Information of China (English)

    任九生; 程昌钧

    2002-01-01

    The spherical cavitated bifurcation for a hyperelastic solid sphere made of the incompressible Valanis-Landel material under boundary dead-loading is examined. The analytic solution for the bifurcation problem is obtained. The catastrophe and concentration of stresses are discussed. The stability of solutions is discussed through the energy comparison.And the growth of a pre-existing micro-void is also observed.

  11. Impact of acoustic cavitation on food emulsions.

    Science.gov (United States)

    Krasulya, Olga; Bogush, Vladimir; Trishina, Victoria; Potoroko, Irina; Khmelev, Sergey; Sivashanmugam, Palani; Anandan, Sambandam

    2016-05-01

    The work explores the experimental and theoretical aspects of emulsification capability of ultrasound to deliver stable emulsions of sunflower oil in water and meat sausages. In order to determine optimal parameters for direct ultrasonic emulsification of food emulsions, a model was developed based on the stability of emulsion droplets in acoustic cavitation field. The study is further extended to investigate the ultrasound induced changes to the inherent properties of raw materials under the experimental conditions of sono-emulsification.

  12. Single bubble sonoluminescence and stable cavitation

    Institute of Scientific and Technical Information of China (English)

    CHEN Qian; QIAN Menglu

    2004-01-01

    A single bubble trapped at an antinode of an acoustic standing wave field in water can emit 50ps-140ps light pulses, called "single bubble sonoluminescence" (SBSL). It arouses much interest in physical acoustics because of its highly non-linear characteristics, high concentration of energy, and stable cavitation behavior. In this paper, bubble stability, the dynamic behavior of bubbles, non-invasive measurement of driving acoustic pressure and Mie scattering method are introduced.

  13. Photoacoustic cavitation for theranostics: mechanism, current progress and applications

    Science.gov (United States)

    Feng, Y.; Qin, D.; Wan, M.

    2015-12-01

    As an emerging cavitation technology, photoacoustic cavitation (PAC) means the formation of bubbles in liquids using focused laser and pre-established ultrasound synchronously. Its significant advantages include the decreased threshold of each modality and the precise location of cavitation determined by the focused laser. In this paper, a brief review of PAC is presented, including the physical mechanism description, the classic experimental technology, the representative results in variety of media, and its applications in biomedical imaging and therapy. Moreover, some preliminary results of PAC in perfluoropentane (PFP) liquid and PFP droplets investigated by passive cavitation detection (PCD) in our group are also presented.

  14. Understanding Cavitation Intensity through Pitting and Pressure Pulse Analysis

    Science.gov (United States)

    Jayaprakash, A.; Singh, S.; Choi, J.-K.; Chahine, G.

    2011-11-01

    Cavitation erosion is of interest to the designers of ship propulsion devices because of its detrimental effects. One of the difficulties of predicting cavitation erosion is that the intensity of cavitation is not well predicted or defined. In this work we attempt to define the intensity of a cavitation erosion field through analysis of cavitation induced erosion pits and pressure pulses. In the pitting tests, material samples were subjected to cavitation field for a short duration of time selected within the test sample's incubation period, so that the test sample undergoes plastic deformation only. The sample material reacts to these cavitation events by undergoing localized permanent deformation, called pits. The resulting pitted sample surfaces were then optically scanned and analyzed. The pressure signals under cavitating jets and ultrasonic horns, for different conditions, were experimentally recorded using high frequency response pressure transducers. From the analysis of the pitting data and recorded pressure signals, we propose a model that describes the statistics, which in the future can be used to define the cavitation field intensity. Support for this work was provided by Office of Naval Research (ONR) under contract number N00014-08-C-0450, monitored by Dr. Ki-Han Kim.

  15. Modeling Unsteady Cavitation Effects and Dynamic Loads in Cryogenic Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There currently are no analytical or CFD tools that can reliably predict unsteady cavitation dynamics in liquid rocket turbopumps. Cavitation effects, particularly...

  16. The upgraded external-beam PIXE/PIGE set-up at LABEC for very fast measurements on aerosol samples

    Energy Technology Data Exchange (ETDEWEB)

    Lucarelli, F.; Calzolai, G.; Chiari, M.; Mochi, D.; Nava, S. [Department of Physics, University of Florence and INFN, Florence (Italy)

    2013-07-01

    Full text: Particle Induced X-ray Emission (PIXE)technique has been widely used since its birth for the study of the aerosol composition, and for a long time it has been the dominating technique for its elemental analysis. However now it has to compete with other techniques, like Induced Coupled Plasma and detection by Atomic Emission Spectroscopy (ICP-AES) or Mass Spectrometry (ICP-MS) or Synchrotron Radiation XRF (SR-XRF). To remain competitive, a proper experimental set-up is important to fully exploit PIXE capabilities. At LABEC, an external beam line is fully dedicated to PIXE-PIGE measurements of atmospheric aerosols [1]. Recently SDD (Silicon Drift Detectors) have been introduced for X-ray detection thanks to their better resolution with respect to Si(Li) detectors and the possibility of managing high counting rates (up to 50 kHz at 0.5 μsec shaping time). This implies, in turn, the possibility of using very high beam currents thus drastically reducing the measurement time. However their use for a complete characterization of X-rays was limited by the small thickness and surface areas available. Now SDD with a thickness of 500 μm and 80 mm{sup 2} area have been introduced in the market. We have therefore replaced the Si(Li) detector used so far for the detection of medium-high Z elements with such a SDD. A comparison of the two detectors has been carried out; PIXE minimum detection limits (MDLs) at different proton beam energies have been studied to find out the best energy for PIXE measurements on aerosol samples collected on different substrata, namely Teflon, Kapton, Nuclepore and Kimfol, used for daily or hourly sampling or for cascade impactors. In particular in the case of Teflon filters, the production of γ-rays by F in the Teflon filter limits the current which may be used and the Compton γ-ray background worsens the MDLs. Due to the lower thickness of the SDD detector with respect to a typical Si(Li) detector, these problems are reduced

  17. Sensitivity testing of the model set-up used for calculation of photochemical ozone creation potentials (POCP) under European conditions

    Energy Technology Data Exchange (ETDEWEB)

    Altenstedt, J.; Pleijel, K.

    1998-02-01

    Photochemical Ozone Creation Potentials (POCP) is a method to rank VOC, relative to other VOC, according to their ability to produce ground level ozone. To obtain POCP values valid under European conditions, a critical analysis of the POCP concept has been performed using the IVL photochemical trajectory model. The critical analysis has concentrated on three VOC (ethene, n-butane and o-xylene) and has analysed the effect on their POCP values when different model parameters were varied. The three species were chosen because of their different degradation mechanisms in the atmosphere and thus their different abilities to produce ozone. The model parameters which have been tested include background emissions, initial concentrations, dry deposition velocities, the features of the added point source and meteorological parameters. The critical analysis shows that the background emissions of NO{sub x} and VOC have a critical impact on the POCP values. The hour of the day for the point source emission also shows a large influence on the POCP values. Other model parameters which have been studied have not shown such large influence on the POCP values. Based on the critical analysis a model set-up for calculation of POCP is defined. The variations in POCP values due to changes in the background emissions of NO{sub x} and VOC are so large that they can not be disregarded in the calculation of POCP. It is recommended to calculate POCP ranges based on the extremes in POCP values instead of calculating site specific POCP values. Four individual emission scenarios which produced the extremes in POCP values in the analysis have been selected for future calculation of POCP ranges. The scenarios are constructed based on the emissions in Europe and the resulting POCP ranges are thus intended to be applicable within Europe 67 refs, 61 figs, 16 tabs

  18. Prenatal detection of aneuploidies using fluorescence in situ hybridization: A preliminary experience in an Indian set up

    Indian Academy of Sciences (India)

    Vaidehi Jobanputra; Kalol Kumar Roy; Kiran Kucheria

    2002-03-01

    Fluorescence in situ hybridization (FISH) is a powerful molecular cytogenetic technique which allows rapid detection of aneuploidies on interphase cells and metaphase spreads. The aim of the present study was to evaluate FISH as a tool in prenatal diagnosis of aneuploidies in high risk pregnancies in an Indian set up. Prenatal diagnosis was carried out in 88 high-risk pregnancies using FISH and cytogenetic analysis. Multicolour commercially available FISH probes specific for chromosomes 13, 18, 21, X and Y were used. Interphase FISH was done on uncultured cells from chorionic villus and amniotic fluid samples. FISH on metaphase spreads was done from cord blood samples. The results of FISH were in conformity with the results of cytogenetic analysis in all the normal and aneuploid cases except in one case of structural chromosomal abnormality. The hybridization efficiency of the 5 probes used for the detection of aneuploidies was 100%. Using these probes FISH assay yielded discrete differences in the signal profiles between cytogenetically normal and abnormal samples. The overall mean interphase disomic signal patterns of chromosomes 13, 18, 21, X and Y were 94.45%; for interphase trisomic signal pattern of chromosome 21 was 97.3%. Interphase FISH is very useful in urgent high risk cases. The use of FISH overcomes the difficulties of conventional banding on metaphase spreads and reduces the time of reporting. However, with the limited number of probes used, the conventional cytogenetic analysis serves as a gold standard at present. It should be employed as an adjunctive tool to conventional cytogenetics.

  19. In vivo dosimetry of high-dose fractionated irradiation in an experimental set-up with rats

    Energy Technology Data Exchange (ETDEWEB)

    Fortan, L.; Van Hecke, H.; Van Duyse, B.; De Neve, W.; De Meerleer, B. [Ghent Rijksuniversiteit (Belgium). Kliniek voor Radiotherapie en Kerngeneeskunde; Pattyn, P.; Van Renthergem, K. [Ghent University (Belgium). Dept. of Surgery

    1995-12-01

    The feasibility to irradiate a limited section of a rat abdomen with well-defined edges was assessed. Because of the relative small volume involved, in vivo dosimetry with TLDs was necessary in providing us information about the accuracy of the irradiation method. Three to five days prior to the start of the radiotherapy treatment, two plastic strips - each containing a TLD-dosimeter (Harshaw TLD10 LiF rods, 1 mm dia x 6 mm) sealed in polyethylene tubing, and a lead bean - were implanted in the rat abdomen. The plastic strips made a closed loop around the bowel, through the mesenterium, and were fixed with a single stitch on the inner abdominal wall. One loop was made in the hepatic area; another was made in the lower abdomen, around the rectosigmoid. Conscious animals were irradiated using a purpose-build plexi-holder, with rear legs immobilised to avoid longitudinal movements. The implanted lead beans enabled us to simulate the rat prior to each radiation session. This way, the radiation field could be set up individually for each rat, in such way that the rectosigmoid area received full dose and the hepatic area received no irradiation dose at all. Irradiation was carried out, using 5 MV photons of a linear accelerator. Fifteen animals per group were irradiated according a conventional (2.0 Gy / fraction; 5 fractions / week) or a hyperfractionated (1.6 Gy / fraction; 2 daily fractions; 5 days / week) schedule, with different total doses. Prior to implantation, TLDs were individually calibrated and checked for stability. After removal from the abdomen . TLDs were tested again for accuracy. TLDs with an unacceptable read-out curve were rejected (about 2 to 4 TLDs per group of 15). The obtained accumulated doses - as determined by TLD read-outs-were comparable to the theoretical doses, indicating that fractionated radiation of small fields, with well defined mark off, in rats is feasible.

  20. Capillary electrophoresis-atmospheric pressure chemical ionization-mass spectrometry using an orthogonal interface: set-up and system parameters.

    Science.gov (United States)

    Hommerson, Paul; Khan, Amjad M; de Jong, Gerhardus J; Somsen, Govert W

    2009-07-01

    The feasibility of atmospheric pressure chemical ionization (APCI) as an alternative ionization technique for capillary electrophoresis-mass spectrometry (CE-MS) was investigated using a grounded sheath-flow CE-MS sprayer and an orthogonal APCI source. Infusion experiments indicated that highest analyte signals were achieved when the sprayer tip was in close vicinity of the vaporizer entrance. The APCI-MS set-up enabled detection of basic, neutral, and acidic compounds, whereas apolar and ionic compounds could not be detected. In the positive ion mode, analytes could be detected in the entire transfer voltage range (0-5 kV), whereas highest signal intensities were observed when the corona discharge current was between 1000 and 2000 nA. In the negative ion mode, the transfer voltage typically was 500 V and the optimum corona discharge current was 6000 nA. Analyte signals were raised with increasing nebulizing gas pressure, but the pressure was limited to 25 psi to avoid siphoning and current drops. Signal intensities appeared to be optimal and constant over a wide range of sheath liquid flow rate (5-25 microL/min) and vaporizer temperature (200-350 degrees C). APCI-MS signals were unaffected by the composition of the background electrolyte (BGE), even when it contained sodium phosphate and sodium dodecyl sulfate (SDS). Consequently, BGE composition, sheath-liquid flow rate, and vaporizer temperature can be optimized with respect to the CE separation without affecting the APCI-MS response. The analysis of a mixture of basic compounds and a steroid using volatile and nonvolatile BGEs further demonstrates the feasibility of CE-APCI-MS. Detection limits (S/N = 3) were 1.6-10 microM injected concentrations.

  1. Uncertainties in surface mass and energy flux estimates due to different eddy covariance sensors and technical set-up

    Science.gov (United States)

    Arriga, Nicola; Fratini, Gerardo; Forgione, Antonio; Tomassucci, Michele; Papale, Dario

    2010-05-01

    Eddy covariance is a well established and widely used methodology for the measurement of turbulent fluxes of mass and energy in the atmospheric boundary layer, in particular to estimate CO2/H2O and heat exchange above ecologically relevant surfaces (Aubinet 2000, Baldocchi 2003). Despite its long term application and theoretical studies, many issues are still open about the effect of different experimental set-up on final flux estimates. Open issues are the evaluation of the performances of different kind of sensors (e.g. open path vs closed path infra-red gas analysers, vertical vs horizontal mounting ultrasonic anemometers), the quantification of the impact of corresponding physical corrections to be applied to get robust flux estimates taking in account all processes concurring to the measurement (e.g. the so-called WPL term, signal attenuation due to air sampling system for closed path analyser, relative position of analyser and anemometer) and the differences between several data transmission protocols used (analogue, digital RS-232, SDM). A field experiment was designed to study these issues using several instruments among those most used within the Fluxnet community and to compare their performances under conditions supposed to be critical: rainy and cold weather conditions for open-path analysers (Burba 2008), water transport and absorption at high air relative humidity conditions for closed-path systems (Ibrom, 2007), frequency sampling limits and recorded data robustness due to different transmission protocols (RS232, SDM, USB, Ethernet) and finally the effect of the displacement between anemometer and analyser using at least two identical analysers placed at different horizontal and vertical distances from the anemometer. Aim of this experiment is to quantify the effect of several technical solutions on the final estimates of fluxes measured at a point in the space and if they represent a significant source of uncertainty for mass and energy cycle

  2. Decompression induced bubble dynamics on ex vivo fat and muscle tissue surfaces with a new experimental set up.

    Science.gov (United States)

    Papadopoulou, Virginie; Evgenidis, Sotiris; Eckersley, Robert J; Mesimeris, Thodoris; Balestra, Costantino; Kostoglou, Margaritis; Tang, Meng-Xing; Karapantsios, Thodoris D

    2015-05-01

    Vascular gas bubbles are routinely observed after scuba dives using ultrasound imaging, however the precise formation mechanism and site of these bubbles are still debated and growth from decompression in vivo has not been extensively studied, due in part to imaging difficulties. An experimental set-up was developed for optical recording of bubble growth and density on tissue surface area during hyperbaric decompression. Muscle and fat tissues (rabbits, ex vivo) were covered with nitrogen saturated distilled water and decompression experiments performed, from 3 to 0bar, at a rate of 1bar/min. Pictures were automatically acquired every 5s from the start of the decompression for 1h with a resolution of 1.75μm. A custom MatLab analysis code implementing a circular Hough transform was written and shown to be able to track bubble growth sequences including bubble center, radius, contact line and contact angles over time. Bubble density, nucleation threshold and detachment size, as well as coalescence behavior, were shown significantly different for muscle and fat tissues surfaces, whereas growth rates after a critical size were governed by diffusion as expected. Heterogeneous nucleation was observed from preferential sites on the tissue substrate, where the bubbles grow, detach and new bubbles form in turn. No new nucleation sites were observed after the first 10min post decompression start so bubble density did not vary after this point in the experiment. In addition, a competition for dissolved gas between adjacent multiple bubbles was demonstrated in increased delay times as well as slower growth rates for non-isolated bubbles.

  3. Anisotropic hydrodynamics -- basic concepts

    CERN Document Server

    Florkowski, Wojciech; Ryblewski, Radoslaw; Strickland, Michael

    2013-01-01

    Due to the rapid longitudinal expansion of the quark-gluon plasma created in relativistic heavy ion collisions, potentially large local rest frame momentum-space anisotropies are generated. The magnitude of these momentum-space anisotropies can be so large as to violate the central assumption of canonical viscous hydrodynamical treatments which linearize around an isotropic background. In order to better describe the early-time dynamics of the quark gluon plasma, one can consider instead expanding around a locally anisotropic background which results in a dynamical framework called anisotropic hydrodynamics. In this proceedings contribution we review the basic concepts of the anisotropic hydrodynamics framework presenting viewpoints from both the phenomenological and microscopic points of view.

  4. Visualization of cavitation in flanged poppet valve; Tsubatsuki popetto bennai no cavitation no kashika

    Energy Technology Data Exchange (ETDEWEB)

    Iijima, A.; Tsukiji, T. [Ashikaga Institute of Technology, Tochigi (Japan); Sumita, T. [Tokimec Inc., Tokyo (Japan)

    1999-01-15

    Only half-cut models are dealt with in reports made available so far about experiments on the visualization of cavitation in what is called a flanged poppet valve, which is a valve whose cone-shaped poppet is provided with flanges at its end and periphery for reduction in fluid force. In the present report, a valve is drilled from three directions in an experiment for visualizing flows near the poppet valve flanges, which is for three-dimensional model visualization. The shapes of the poppet valve flanges are changed in various ways for the study of cavitation generation limits. (translated by NEDO)

  5. Dispersive hydrodynamics: Preface

    Science.gov (United States)

    Biondini, G.; El, G. A.; Hoefer, M. A.; Miller, P. D.

    2016-10-01

    This Special Issue on Dispersive Hydrodynamics is dedicated to the memory and work of G.B. Whitham who was one of the pioneers in this field of physical applied mathematics. Some of the papers appearing here are related to work reported on at the workshop "Dispersive Hydrodynamics: The Mathematics of Dispersive Shock Waves and Applications" held in May 2015 at the Banff International Research Station. This Preface provides a broad overview of the field and summaries of the various contributions to the Special Issue, placing them in a unified context.

  6. Contrast-Enhanced Proton Radiography for Patient Set-up by Using X-Ray CT Prior Knowledge

    Energy Technology Data Exchange (ETDEWEB)

    Spadea, Maria Francesca, E-mail: mfspadea@unicz.it [Department of Experimental and Clinical Medicine, Magna Graecia University, Catanzaro (Italy); Fassi, Aurora [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Zaffino, Paolo [Department of Experimental and Clinical Medicine, Magna Graecia University, Catanzaro (Italy); Riboldi, Marco; Baroni, Guido [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano (Italy); Bioengineering Unit—CNAO Foundation, Pavia (Italy); Depauw, Nicolas [Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts (United States); Centre for Medical Radiation Physics, University of Wollongong, Wollongong (Australia); Seco, Joao [Department of Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-11-01

    Purpose: To obtain a contrasted image of the tumor region during the setup for proton therapy in lung patients, by using proton radiography and x-ray computed tomography (CT) prior knowledge. Methods and Materials: Six lung cancer patients' CT scans were preprocessed by masking out the gross tumor volume (GTV), and digitally reconstructed radiographs along the planned beam's eye view (BEV) were generated, for a total of 27 projections. Proton radiographies (PR) were also computed for the same BEV through Monte Carlo simulations. The digitally reconstructed radiograph was subtracted from the corresponding proton image, resulting in a contrast-enhanced proton radiography (CEPR). Michelson contrast analysis was performed both on PR and CEPR. The tumor region was then automatically segmented on CEPR and compared to the ground truth (GT) provided by physicians in terms of Dice coefficient, accuracy, precision, sensitivity, and specificity. Results: Contrast on CEPR was, on average, 4 times better than on PR. For 10 lateral projections (±45° off of 90° or 270°), although it was not possible to distinguish the tumor region in the PR, CEPR offers excellent GTV visibility. The median ± quartile values of Dice, precision, and accuracy indexes were 0.86 ± 0.03, 0.86 ± 0.06, and 0.88 ± 0.02, respectively, thus confirming the reliability of the method in highlighting tumor boundaries. Sensitivity and specificity analysis demonstrated that there is no systematic over- or underestimation of the tumor region. Identification of the tumor boundaries using CEPR resulted in a more accurate and precise definition of GTV compared to that obtained from pretreatment CT. Conclusions: In most proton centers, the current clinical protocol is to align the patient using kV imaging with bony anatomy as a reference. We demonstrated that CEPR can significantly improve tumor visualization, allowing better patient set-up and permitting image guided proton therapy (IGPT)

  7. The Interaction Between Dynamics and Chemistry of Ozone in the Set-up Phase of the Northern Hemisphere Polar Vortex

    Science.gov (United States)

    Kawa, S. R.; Bevilacqua, R.; Margitan, J. J.; Douglass, A. R.; Schoeberl, M. R.; Hoppel, K.; Sen, B.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    The morphology and evolution of the stratospheric ozone (O3) distribution at high latitudes in the Northern Hemisphere (NH) are examined for the late summer and fall seasons of 1999. This time period sets the O3 initial condition for the SOLVE/THESEO field mission performed during winter 1999-2000. In situ and satellite data are used along with a three-dimensional model of chemistry and transport (CTM) to determine the key processes that control the distribution of O3 in the lower-to-middle stratosphere. O3 in the vortex at the beginning of the winter season is found to be nearly constant from 500 to above 800 K with a value at 3 ppmv +/- approx. 10%. Values outside the vortex are up to a factor of 2 higher and increase significantly with potential temperature. The seasonal time series of data from POAM shows that relatively low O3 mixing ratios, which characterize the vortex in late fall, are already present at high latitudes at the end of summer before the vortex circulation sets up. Analysis of the CTM output shows that the minimum O3 and increase in variance in late summer are the result of: 1) stirring of polar concentric O3 gradients by nascent wave-driven transport, and 2) an acceleration of net photochemical loss with decreasing solar illumination. The segregation of low O3 mixing ratios into the vortex as the circulation strengthens through the fall suggests a possible feedback role between O3 chemistry and the vortex formation dynamics. Trajectory calculations from O3 sample points early in the fall, however, show only a weak correlation between initial O3 mixing ratio and potential vorticity later in the season consistent with order-of-magnitude calculations for the relative importance of O3 in the fall radiative balance at high latitudes. The possible connection between O3 chemistry and the dynamics of vortex formation does suggest that these feedbacks and sensitivities need to be better understood in order to make confident predictions of the recovery

  8. A new set-up for in-situ probing of radiation effects in materials and electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Peres, M.; Felizardo, M.; Catarino, N.; Alves, L.C. [Instituto Superior Tecnico - IST, Campus Tecnologico e Nuclear, Estrada Nacional 10, P-2695-066 Bobadela LRS (Portugal); Cruz, C.; Alves, E.; Lorenz, K. [Instituto Superior Tecnico - IST, Campus Tecnologico e Nuclear, Estrada Nacional 10, P-2695-066 Bobadela LRS (Portugal); IPFN, IST (Portugal)

    2015-07-01

    The micro-probe facility installed at the Van de Graff accelerator at CTN/IST permits simultaneous measurements of Rutherford Backscattering Spectrometry (RBS), Particle Induced X-ray Emission (PIXE) and Iono-Luminescence (IL). Here we present a recent up-grade of the measurement chamber allowing improved optical sensitivity in IL measurements and opening the possibility to perform simultaneously electrical measurements. Combinations of all these characterization techniques make this setup a powerful tool to characterize and modify different materials with spatial resolution. In particular, it can be used to study radiation effects in different materials and electronic devices in-situ. IL is a luminescence technique that uses the ion beam as the excitation source. Compared with other luminescence techniques with spatial resolution like Cathodoluminescence, this technique has the advantage to probe deeper regions of the sample, several microns below the surface. The same ion beam used to produce luminescence, can create a high density of defects, in a controllable way and the new set-up allows monitoring optical and electrical properties in realtime. In this work we combine IL with I-V curve measurements to assess the response of Ga{sub 2}O{sub 3} and GaN to proton irradiation. Ga{sub 2}O{sub 3} and GaN are emerging materials for applications in high power electronics and are considered for radiation resistant electronics. We will present a systematic study of the changes in IL and conductivity in Ga{sub 2}O{sub 3} and GaN samples with the energy of the ion beam and with the time of exposure. In particular, it was observed that during the irradiation some luminescence bands related with intrinsic point defects decrease while other new bands appear. Simulations using the SRIM code were used to determine the depth profiles of ionization and displacement events, helping to correlate the optical and electrical response of the materials with certain radiation effects

  9. Generating optimal initial conditions for smooth particle hydrodynamics (SPH) simulations

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, Steven [Los Alamos National Laboratory; Rockefeller, Gabriel M [Los Alamos National Laboratory; Fryer, Christopher L [Los Alamos National Laboratory

    2008-01-01

    We present a new optimal method to set up initial conditions for Smooth Particle Hydrodynamics Simulations, which may also be of interest for N-body simulations. This new method is based on weighted Voronoi tesselations (WVTs) and can meet arbitrarily complex spatial resolution requirements. We conduct a comprehensive review of existing SPH setup methods, and outline their advantages, limitations and drawbacks. A serial version of our WVT setup method is publicly available and we give detailed instruction on how to easily implement the new method on top of an existing parallel SPH code.

  10. INTERFERENCE OF SIDE STRUT WITH THE NATURAL CAVITATING FLOWS AROUND A SUBMERGED VEHICLE IN WATER TUNNEL EXPERIMENTS

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin; YAO Yan; LU Chuan-jing; CHEN Ying; CAOJia-yi

    2011-01-01

    To apply the measurements of model experiment in water tunnel to the actual sailing condition,it is necessary to know accurately the strut effect and its rule.In the present work,the corresponding interferences of one-side strut and two-side strut on the natural cavitating flows around a submerged vehicle in water tunnel were investigated numerically,using the homogeneous equilibrium two-phase model coupled with a natural cavitation model.The numerical simulation results show that the strut types have distinct effects on the hydrodynamic properties.For the same given upstream velocity and downstream pressure,the existence of the strut leads to an increment of natural cavitation number,reduces the low-pressure region and depresses the pressure on the vehicle surface near the sides of strut.In the case of given cavitaiton number,the influences of the two-side strut on the drag and lift coefficients are both enhanced along with the increment of attack angle,however the influence of the one-side strut gradually gets stronger on the drag coefficient but weaker on the lift coefficient contrarily.In addition,based on the present numerical results,a correction method by introducing the sigmoidal logistic function is proposed to eliminate the interference from the foil-shaped strut.

  11. Smoothed Particle Hydrodynamic Simulator

    Energy Technology Data Exchange (ETDEWEB)

    2016-10-05

    This code is a highly modular framework for developing smoothed particle hydrodynamic (SPH) simulations running on parallel platforms. The compartmentalization of the code allows for rapid development of new SPH applications and modifications of existing algorithms. The compartmentalization also allows changes in one part of the code used by many applications to instantly be made available to all applications.

  12. Hydrodynamic aspect of caves

    Directory of Open Access Journals (Sweden)

    Franci Gabrovsek

    2008-01-01

    Full Text Available From a hydrological point of view, active caves are a series of connected conduits which drain water through an aquifer. Water tends to choose the easiest way through the system but different geological and morphological barriers act as flow restrictions. The number and characteristics of restrictions depends on the particular speleogenetic environment, which is a function of geological, geomorphological, climatological and hydrological settings. Such a variety and heterogeneity of underground systems has presented a challenge for human understanding for many centuries. Access to many underground passages, theoretical knowledge and recent methods (modeling, water pressure-resistant dataloggers, precise sensors etc. give us the opportunity to get better insight into the hydrodynamic aspect of caves. In our work we tried to approach underground hydrodynamics from both theoretical and practical points of view. We present some theoretical background of open surface and pressurized flow in underground rivers and present results of some possible scenarios. Moreover, two case studies from the Ljubljanica river basin are presented in more detail: the cave system between Planinsko polje and Ljubljansko barje, and the cave system between Bloško polje and Cerkniško polje. The approach and methodology in each case is somewhat different, as the aims were different at the beginning of exploration. However, they both deal with temporal and spatial hydrodynamics of underground waters. In the case of Bloško polje-Cerkniško polje system we also explain the feedback loop between hydrodynamics and Holocene speleogenesis.

  13. Observation of Self-Cavitating Envelope Dispersive Shock Waves in Yttrium Iron Garnet Thin Films.

    Science.gov (United States)

    Janantha, P A Praveen; Sprenger, Patrick; Hoefer, Mark A; Wu, Mingzhong

    2017-07-14

    The formation and properties of envelope dispersive shock wave (DSW) excitations from repulsive nonlinear waves in a magnetic film are studied. Experiments involve the excitation of a spin wave step pulse in a low-loss magnetic Y_{3}Fe_{5}O_{12} thin film strip, in which the spin wave amplitude increases rapidly, realizing the canonical Riemann problem of shock theory. Under certain conditions, the envelope of the spin wave pulse evolves into a DSW that consists of an expanding train of nonlinear oscillations with amplitudes increasing from front to back, terminated by a black soliton. The onset of DSW self-cavitation, indicated by a point of zero power and a concomitant 180° phase jump, is observed for sufficiently large steps, indicative of the bidirectional dispersive hydrodynamic nature of the DSW. The experimental observations are interpreted with theory and simulations of the nonlinear Schrödinger equation.

  14. Breakup of small aggregates driven by turbulent hydrodynamic stress

    CERN Document Server

    Babler, Matthaus U; Lanotte, Alessandra S

    2012-01-01

    Breakup of small solid aggregates in homogeneous and isotropic turbulence is studied theoretically and by using Direct Numerical Simulations at high Reynolds number, Re_{\\lambda} \\simeq 400. We show that turbulent fluctuations of the hydrodynamic stress along the aggregate trajectory play a key role in determining the aggregate mass distribution function. Differences between turbulent and laminar flows are discussed. A novel definition of the fragmentation rate is proposed in terms of the typical frequency at which the hydrodynamic stress becomes sufficiently high to cause breakup along each Lagrangian path. We also define an Eulerian proxy of the real fragmentation rate, based on the joint statistics of the stress and its time derivative, which should be easier to measure in any experimental set-up. Both our Eulerian and Lagrangian formulations define a clear procedure for the computation of the mass distribution function due to fragmentation. Contrary, previous estimates based only on single point statistic...

  15. Compressible Turbulent Flow Numerical Simulations of Tip Vortex Cavitation

    NARCIS (Netherlands)

    Khatami, F.; Weide, van der E.T.A.; Hoeijmakers, H.W.M.

    2015-01-01

    For an elliptic Arndt’s hydrofoil numerical simulations of vortex cavitation are presented. An equilibrium cavitation model is employed. This single-fluid model assumes local thermodynamic and mechanical equilibrium in the mixture region of the flow, is employed. Furthermore, for characterizing the

  16. Pressure and velocity dependence of flow-type cavitation erosion

    CSIR Research Space (South Africa)

    Auret, JG

    1993-12-01

    Full Text Available of underpressure expands for the higher velocity vOz. Thus cavitation bubbles leave this region farther downstream and the erosion zone shifts down- stream. At the same time, cavitation damage will in- crease because of the larger...

  17. Cavitation Measurement during Sonic and Ultrasonic Activated Irrigation

    NARCIS (Netherlands)

    Macedo, R.G.; Verhaagen, B.; Fernandez Rivas, David; Versluis, Andreas Michel; Wesselink, P.R.; van der Sluis, L.W.M.

    2014-01-01

    Introduction The aims of this study were to quantify and to visualize the possible occurrence of transient cavitation (bubble formation and implosion) during sonic and ultrasonic (UAI) activated irrigation. Methods The amount of cavitation generated around several endodontic instruments was measured

  18. Cavitation measurement during sonic and ultrasonic activated irrigation

    NARCIS (Netherlands)

    Macedo, R.; Verhaagen, B.; Fernandez Rivas, D.; Versluis, M.; Wesselink, P.; van der Sluis, L.

    2014-01-01

    Introduction The aims of this study were to quantify and to visualize the possible occurrence of transient cavitation (bubble formation and implosion) during sonic and ultrasonic (UAI) activated irrigation. Methods The amount of cavitation generated around several endodontic instruments was measured

  19. Cavitation-aided grain refinement in aluminium alloys

    NARCIS (Netherlands)

    Atamanenko, T.V.

    2010-01-01

    This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the

  20. Cavitation-aided grain refinement in aluminium alloys

    NARCIS (Netherlands)

    Atamanenko, T.V.

    2010-01-01

    This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the conditi