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Sample records for hydrodynamic cavitation set-up

  1. Hydrodynamic cavitation for sonochemical effects.

    Science.gov (United States)

    Moholkar, V S; Kumar, P S; Pandit, A B

    1999-03-01

    A comparative study of hydrodynamic and acoustic cavitation has been made on the basis of numerical solutions of the Rayleigh-Plesset equation. The bubble/cavity behaviour has been studied under both acoustic and hydrodynamic cavitation conditions. The effect of varying pressure fields on the collapse of the cavity (sinusoidal for acoustic and linear for hydrodynamic) and also on the latter's dynamic behaviour has been studied. The variations of parameters such as initial cavity size, intensity of the acoustic field and irradiation frequency in the case of acoustic cavitation, and initial cavity size, final recovery pressure and time for pressure recovery in the case of hydrodynamic cavitation, have been found to have significant effects on cavity/bubble dynamics. The simulations reveal that the bubble/cavity collapsing behaviour in the case of hydrodynamic cavitation is accompanied by a large number of pressure pulses of relatively smaller magnitude, compared with just one or two pulses under acoustic cavitation. It has been shown that hydrodynamic cavitation offers greater control over operating parameters and the resultant cavitation intensity. Finally, a brief summary of the experimental results on the oxidation of aqueous KI solution with a hydrodynamic cavitation set-up is given which supports the conclusion of this numerical study. The methodology presented allows one to manipulate and optimise of specific process, either physical or chemical.

  2. Modeling hydrodynamic cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, P.S.; Pandit, A.B. [Mumbai Univ. (India). Chemical Engineering Div.

    1999-12-01

    Cavitation as a source and method of energy input for chemical processing is increasingly studied due to its ability to generate localized high temperatures and pressures under nearly ambient conditions. Compared to cavitation generated by ultrasound, hydrodynamic cavitation has been proved to be a very energy-efficient alternative. A simple and unified model has been developed to study the cavitation phenomena in hydraulic systems with emphasis on the venturi tube and high-speed homogenizer. The model has been found to be satisfactory in explaining the effect of operating variables and equipment geometry on two different modes of cavitation generation qualitatively and in some cases quantitatively. (orig.)

  3. Hemolytic potential of hydrodynamic cavitation.

    Science.gov (United States)

    Chambers, S D; Bartlett, R H; Ceccio, S L

    2000-08-01

    The purpose of this study was to determine the hemolytic potentials of discrete bubble cavitation and attached cavitation. To generate controlled cavitation events, a venturigeometry hydrodynamic device, called a Cavitation Susceptibility Meter (CSM), was constructed. A comparison between the hemolytic potential of discrete bubble cavitation and attached cavitation was investigated with a single-pass flow apparatus and a recirculating flow apparatus, both utilizing the CSM. An analytical model, based on spherical bubble dynamics, was developed for predicting the hemolysis caused by discrete bubble cavitation. Experimentally, discrete bubble cavitation did not correlate with a measurable increase in plasma-free hemoglobin (PFHb), as predicted by the analytical model. However, attached cavitation did result in significant PFHb generation. The rate of PFHb generation scaled inversely with the Cavitation number at a constant flow rate, suggesting that the size of the attached cavity was the dominant hemolytic factor.

  4. Occurrence of hydrodynamic cavitation.

    Science.gov (United States)

    Nosov, V R; Gómez-Mancilla, J C; Meda-Campaña, J A

    2011-01-01

    In this paper, the conditions under which cavitation (or liquid film rupture) can or cannot occur in thin layers of moving liquid are derived for three typical cases. At the same time, expressions depending on geometrical and movement parameters, where cavitation might start, are given. The results are obtained using simple engineering terms, which can be used in cases whether it is necessary to avoid cavitation or to induce it.

  5. A theoretical study of hydrodynamic cavitation.

    Science.gov (United States)

    Arrojo, S; Benito, Y

    2008-03-01

    The optimization of hydrodynamic cavitation as an AOP requires identifying the key parameters and studying their effects on the process. Specific simulations of hydrodynamic bubbles reveal that time scales play a major role on the process. Rarefaction/compression periods generate a number of opposing effects which have demonstrated to be quantitatively different from those found in ultrasonic cavitation. Hydrodynamic cavitation can be upscaled and offers an energy efficient way of generating cavitation. On the other hand, the large characteristic time scales hinder bubble collapse and generate a low number of cavitation cycles per unit time. By controlling the pressure pulse through a flexible cavitation chamber design these limitations can be partially compensated. The chemical processes promoted by this technique are also different from those found in ultrasonic cavitation. Properties such as volatility or hydrophobicity determine the potential applicability of HC and therefore have to be taken into account.

  6. Cavitation Generation and Usage Without Ultrasound: Hydrodynamic Cavitation

    Science.gov (United States)

    Gogate, Parag R.; Pandit, Aniruddha B.

    Hydrodynamic Cavitation, which was and is still looked upon as an unavoidable nuisance in the flow systems, can be a serious contender as an alternative to acoustic cavitation for harnessing the spectacular effects of cavitation in physical and chemical processing. The present chapter covers the basics of hydrodynamic cavitation including the considerations for the bubble dynamics analysis, reactor designs and recommendations for optimum operating parameters. An overview of applications in different areas of physical, chemical and biological processing on scales ranging from few grams to several hundred kilograms has also been presented. Since hydrodynamic cavitation was initially proposed as an alternative to acoustic cavitation, it is necessary to compare the efficacy of both these modes of cavitations for a variety of applications and hence comparisons have been discussed either on the basis of energy efficiency or based on the scale of operation. Overall it appears that hydrodynamic cavitation results in conditions similar to those generated using acoustic cavitation but at comparatively much larger scale of operation and with better energy efficiencies.

  7. Towards the concept of hydrodynamic cavitation control

    Science.gov (United States)

    Chatterjee, Dhiman; Arakeri, Vijay H.

    1997-02-01

    A careful study of the existing literature available in the field of cavitation reveals the potential of ultrasonics as a tool for controlling and, if possible, eliminating certain types of hydrodynamic cavitation through the manipulation of nuclei size present in a flow. A glass venturi is taken to be an ideal device to study the cavitation phenomenon at its throat and its potential control. A piezoelectric transducer, driven at the crystal resonant frequency, is used to generate an acoustic pressure field and is termed an ‘ultrasonic nuclei manipulator (UNM)’. Electrolysis bubbles serve as artificial nuclei to produce travelling bubble cavitation at the venturi throat in the absence of a UNM but this cavitation is completely eliminated when a UNM is operative. This is made possible because the nuclei, which pass through the acoustic field first, cavitate, collapse violently and perhaps fragment and go into dissolution before reaching the venturi throat. Thus, the potential nuclei for travelling bubble cavitation at the venturi throat seem to be systematically destroyed through acoustic cavitation near the UNM. From the solution to the bubble dynamics equation, it has been shown that the potential energy of a bubble at its maximum radius due to an acoustic field is negligible compared to that for the hydrodynamic field. Hence, even though the control of hydrodynamic macro cavitation achieved in this way is at the expense of acoustic micro cavitation, it can still be considered to be a significant gain. These are some of the first results in this direction.

  8. Shear viscosity, cavitation and hydrodynamics at LHC

    International Nuclear Information System (INIS)

    Bhatt, Jitesh R.; Mishra, Hiranmaya; Sreekanth, V.

    2011-01-01

    We study evolution of quark-gluon matter in the ultrarelativistic heavy-ion collisions within the frame work of relativistic second-order viscous hydrodynamics. In particular, by using the various prescriptions of a temperature-dependent shear viscosity to the entropy ratio, we show that the hydrodynamic description of the relativistic fluid becomes invalid due to the phenomenon of cavitation. For most of the initial conditions relevant for LHC, the cavitation sets in very early stage. The cavitation in this case is entirely driven by the large values of shear viscosity. Moreover we also demonstrate that the conformal terms used in equations of the relativistic dissipative hydrodynamic can influence the cavitation time.

  9. Hydrodynamic cavitation kills prostate cells and ablates benign prostatic hyperplasia tissue.

    Science.gov (United States)

    Itah, Zeynep; Oral, Ozlem; Perk, Osman Yavuz; Sesen, Muhsincan; Demir, Ebru; Erbil, Secil; Dogan-Ekici, A Isin; Ekici, Sinan; Kosar, Ali; Gozuacik, Devrim

    2013-11-01

    Hydrodynamic cavitation is a physical phenomenon characterized by vaporization and bubble formation in liquids under low local pressures, and their implosion following their release to a higher pressure environment. Collapse of the bubbles releases high energy and may cause damage to exposed surfaces. We recently designed a set-up to exploit the destructive nature of hydrodynamic cavitation for biomedical purposes. We have previously shown that hydrodynamic cavitation could kill leukemia cells and erode kidney stones. In this study, we analyzed the effects of cavitation on prostate cells and benign prostatic hyperplasia (BPH) tissue. We showed that hydrodynamic cavitation could kill prostate cells in a pressure- and time-dependent manner. Cavitation did not lead to programmed cell death, i.e. classical apoptosis or autophagy activation. Following the application of cavitation, we observed no prominent DNA damage and cells did not arrest in the cell cycle. Hence, we concluded that cavitation forces directly damaged the cells, leading to their pulverization. Upon application to BPH tissues from patients, cavitation could lead to a significant level of tissue destruction. Therefore similar to ultrasonic cavitation, we propose that hydrodynamic cavitation has the potential to be exploited and developed as an approach for the ablation of aberrant pathological tissues, including BPH.

  10. Degradation of chlorocarbons driven by hydrodynamic cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Z.L.; Ondruschka, B.; Braeutigam, P. [Institut fuer Technische Chemie und Umweltchemie, Friedrich-Schiller-Universitaet Jena, Jena (Germany)

    2007-05-15

    To provide an efficient lab-scale device for the investigation of the degradation of organic pollutants driven by hydrodynamic cavitation, the degradation kinetics of chloroform and carbon tetrachloride and the increase of conductivity in aqueous solutions were measured. These are values which were not previously available. Under hydrodynamic cavitation conditions, the degradation kinetics for chlorocarbons was found to be pseudo first-order. Meanwhile, C-H and C-Cl bonds are broken, and Cl{sub 2}, Cl{sup .}, Cl{sup -} and other ions released can increase the conductivity and enhance the oxidation of KI in aqueous solutions. The upstream pressures of the orifice plate, the cavitation number, and the solution temperature have substantial effects on the degradation kinetics. A decreased cavitation number can result in more cavitation events and enhances the degradation of chlorocarbons and/or the oxidation of KI. A decrease in temperature is generally favorable to the cavitation chemistry. Organic products from the degradation of carbon tetrachloride and chloroform have demonstrated the formation and recombination of free radicals, e.g., CCl{sub 4}, C{sub 2}Cl{sub 4}, and C{sub 2}Cl{sub 6} are produced from the degradation of CHCl{sub 3}. CHCl{sub 3} and C{sub 2}Cl{sub 6} are produced from the degradation of CCl{sub 4}. Both the chemical mechanism and the reaction kinetics of the degradation of chlorocarbons induced by hydrodynamic cavitation are consistent with those obtained from the acoustic cavitation. Therefore, the technology of hydrodynamic cavitation should be a good candidate for the removal of organic pollutants from water. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  11. Control of hydrodynamic cavitation using ultrasonic

    Science.gov (United States)

    Chatterjee, Dhiman; Arakeri, Vijay H.

    2003-11-01

    Hydrodynamic cavitation is known to have many harmful effects like surface damage and generation of noise. We investigated the use of ultrasonics to control traveling bubble cavitation. Ultrasonic pressure field, produced by a piezoelectric crystal, was applied to modify the nuclei size distribution. Effects of continuous-wave (CW) and pulsed excitations were studied. At low dissolved gas content the CW-mode performed better than the pulsed one, whereas for high gas content the pulsed one was more effective. The dominant mechanisms were Bjerknes force and rectified diffusion in these two cases. Simultaneous excitation by two crystals in CW and pulsed modes was seen to control cavitation better.

  12. Statistical analysis of hydrodynamic cavitation events

    Science.gov (United States)

    Gimenez, G.; Sommer, R.

    1980-10-01

    The frequency (number of events per unit time) of pressure pulses produced by hydrodynamic cavitation bubble collapses is investigated using statistical methods. The results indicate that this frequency is distributed according to a normal law, its parameters not being time-evolving.

  13. Hydrodynamic Cavitation-Assisted Synthesis of Nanocalcite

    Directory of Open Access Journals (Sweden)

    Shirish H. Sonawane

    2010-01-01

    Full Text Available A systematic study was made on the synthesis of nanocalcite using a hydrodynamic cavitation reactor. The effects of various parameters such as diameter and geometry of orifice, CO2 flow rate, and Ca(OH2 concentration were investigated. It was observed that the orifice diameter and its geometry had significant effect on the carbonation process. The reaction rate was significantly faster than that observed in a conventional carbonation process. The particle size was significantly affected by the reactor geometry. The results showed that an orifice with 5 holes of 1 mm size resulted in the particle size reduction to 37 nm. The experimental investigation reveals that hydrodynamic cavitation may be more energy efficient.

  14. Modeling of hydrodynamic cavitation reactors: a unified approach

    NARCIS (Netherlands)

    Moholkar, V.S.; Pandit, A.B.

    2001-01-01

    An attempt has been made to present a unified theoretical model for the cavitating flow in a hydrodynamic cavitation reactor using the nonlinear continuum mixture model for two-phase flow as the basis. This model has been used to describe the radial motion of bubble in the cavitating flow in two

  15. Hydrodynamic cavitation: a bottom-up approach to liquid aeration

    NARCIS (Netherlands)

    Raut, J.S.; Stoyanov, S.D.; Duggal, C.; Pelan, E.G.; Arnaudov, L.N.; Naik, V.M.

    2012-01-01

    We report the use of hydrodynamic cavitation as a novel, bottom-up method for continuous creation of foams comprising of air microbubbles in aqueous systems containing surface active ingredients, like proteins or particles. The hydrodynamic cavitation was created using a converging-diverging nozzle.

  16. Application of Hydrodynamic Cavitation for Food and Bioprocessing

    Science.gov (United States)

    Gogate, Parag R.

    Hydrodynamic cavitation can be simply generated by the alterations in the flow field in high speed/high pressure devices and also by passage of the liquid through a constriction such as orifice plate, venturi, or throttling valve. Hydrodynamic cavitation results in the formation of local hot spots, release of highly reactive free radicals, and enhanced mass transfer rates due to turbulence generated as a result of liquid circulation currents. These conditions can be suitably applied for intensification of different bioprocessing applications in an energy-efficient manner as compared to conventionally used ultrasound-based reactors. The current chapter aims at highlighting different aspects related to hydrodynamic cavitation, including the theoretical aspects for optimization of operating parameters, reactor designs, and overview of applications relevant to food and bioprocessing. Some case studies highlighting the comparison of hydrodynamic cavitation and acoustic cavitation reactors will also be discussed.

  17. Experimental investigation of hydrodynamic cavitation through orifices of different geometries

    Science.gov (United States)

    Rudolf, Pavel; Kubina, Dávid; Hudec, Martin; Kozák, Jiří; Maršálek, Blahoslav; Maršálková, Eliška; Pochylý, František

    Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

  18. Experimental investigation of hydrodynamic cavitation through orifices of different geometries

    Directory of Open Access Journals (Sweden)

    Rudolf Pavel

    2017-01-01

    Full Text Available Hydrodynamic cavitation in single and multihole orifices was experimentally investigated to assess their hydraulic characteristics: loss coefficients, inception cavitation number, cavitation number for transition to supercavitation. Significant difference for singlehole and multihole orifices was observed in terms of the measured loss coefficient. It is significantly more effective to use multihole orifices, where energy dissipation is much lower.It was found that using scaling factor given by ratio of orifice thickness suggests linear behaviour of both loss coefficient and inception cavitation number. Orifices seem to be convenient choice as flow constriction devices inducing cavitation due to their simplicity.

  19. Use of hydrodynamic cavitation in (waste)water treatment.

    Science.gov (United States)

    Dular, Matevž; Griessler-Bulc, Tjaša; Gutierrez-Aguirre, Ion; Heath, Ester; Kosjek, Tina; Krivograd Klemenčič, Aleksandra; Oder, Martina; Petkovšek, Martin; Rački, Nejc; Ravnikar, Maja; Šarc, Andrej; Širok, Brane; Zupanc, Mojca; Žitnik, Miha; Kompare, Boris

    2016-03-01

    The use of acoustic cavitation for water and wastewater treatment (cleaning) is a well known procedure. Yet, the use of hydrodynamic cavitation as a sole technique or in combination with other techniques such as ultrasound has only recently been suggested and employed. In the first part of this paper a general overview of techniques that employ hydrodynamic cavitation for cleaning of water and wastewater is presented. In the second part of the paper the focus is on our own most recent work using hydrodynamic cavitation for removal of pharmaceuticals (clofibric acid, ibuprofen, ketoprofen, naproxen, diclofenac, carbamazepine), toxic cyanobacteria (Microcystis aeruginosa), green microalgae (Chlorella vulgaris), bacteria (Legionella pneumophila) and viruses (Rotavirus) from water and wastewater. As will be shown, hydrodynamic cavitation, like acoustic, can manifest itself in many different forms each having its own distinctive properties and mechanisms. This was until now neglected, which eventually led to poor performance of the technique. We will show that a different type of hydrodynamic cavitation (different removal mechanism) is required for successful removal of different pollutants. The path to use hydrodynamic cavitation as a routine water cleaning method is still long, but recent results have already shown great potential for optimisation, which could lead to a low energy tool for water and wastewater cleaning. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. 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

  1. Numerical and experimental study of a hydrodynamic cavitation tube

    Science.gov (United States)

    Hu, H.; Finch, J. A.; Zhou, Z.; Xu, Z.

    1998-08-01

    A numerical analysis of hydrodynamics in a cavitation tube used for activating fine particle flotation is described. Using numerical procedures developed for solving the turbulent k-ɛ model with boundary fitted coordinates, the stream function, vorticity, velocity, and pressure distributions in a cavitation tube were calculated. The calculated pressure distribution was found to be in excellent agreement with experimental results. The requirement of a pressure drop below approximately 10 m water for cavitation to occur was observed experimentally and confirmed by the model. The use of the numerical procedures for cavitation tube design is discussed briefly.

  2. Hydrodynamic cavitation in Stokes flow of anisotropic fluids

    Science.gov (United States)

    Stieger, Tillmann; Agha, Hakam; Schoen, Martin; Mazza, Marco G.; Sengupta, Anupam

    2017-05-01

    Cavitation, the nucleation of vapour in liquids, is ubiquitous in fluid dynamics, and is often implicated in a myriad of industrial and biomedical applications. Although extensively studied in isotropic liquids, corresponding investigations in anisotropic liquids are largely lacking. Here, by combining liquid crystal microfluidic experiments, nonequilibrium molecular dynamics simulations and theoretical arguments, we report flow-induced cavitation in an anisotropic fluid. The cavitation domain nucleates due to sudden pressure drop upon flow past a cylindrical obstacle within a microchannel. For an anisotropic fluid, the inception and growth of the cavitation domain ensued in the Stokes regime, while no cavitation was observed in isotropic liquids flowing under similar hydrodynamic parameters. Using simulations we identify a critical value of the Reynolds number for cavitation inception that scales inversely with the order parameter of the fluid. Strikingly, the critical Reynolds number for anisotropic fluids can be 50% lower than that of isotropic fluids.

  3. Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems

    OpenAIRE

    Ferrari, A.

    2017-01-01

    Cavitation is the transition from a liquid to a vapour phase, due to a drop in pressure to the level of the vapour tension of the fluid. Two kinds of cavitation have been reviewed here: acoustic cavitation and hydrodynamic cavitation. As acoustic cavitation in engineering systems is related to the propagation of waves through a region subjected to liquid vaporization, the available expressions of the sound speed are discussed. One of the main effects of hydrodynamic cavitation in the nozzles ...

  4. An experimental investigation of hydrodynamic cavitation in micro-Venturis

    Science.gov (United States)

    Mishra, Chandan; Peles, Yoav

    2006-10-01

    The existence of hydrodynamic cavitation in the flow of de-ionized water through micro-Venturis has been witnessed in the form of traveling bubble cavitation and fully developed streamer bubble/supercavitation, and their mechanisms have been discussed. High-speed photography and flow visualization disclose inchoate cavitation bubbles emerging downstream from the micro-Venturi throat and the presence of a single streamer bubble/supercavity, which is equidistant from the micro device walls. The supercavity initiates inside the diffuser section and extends until the microchannel exit and proceeds to bifurcate the incoming flow. This article strives to provide numerical data and experimental details of hydrodynamic cavitation taking place within micro-Venturis.

  5. 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.

  6. Biodiesel production through hydrodynamic cavitation and performance testing

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Amit; Verma, Ashish; Kachhwaha, S.S.; Maji, S. [Department of Mechanical Engineering, Delhi College of Engineering, Bawana Road, Delhi 110042 (India)

    2010-03-15

    This paper presents the details of development of a biodiesel production test rig based on hydrodynamic cavitation followed by results of experimental investigation carried out on a four cylinder, direct injection water cooled diesel engine operating on diesel and biodiesel blend of Citrullus colocyntis (Thumba) oil. The experiment covers a wide range of engine rpm. Results show that biodiesel of Thumba oil produced through hydrodynamic cavitation technique can be used as an alternative fuel with better performance and lower emissions compared to diesel. The most significant conclusions are that (1) Biodiesel production through hydrodynamic cavitation technique seems to be a simple, efficient, time saving, eco-friendly and industrially viable process. (2) 30% biodiesel blend of Thumba oil shows relatively higher brake power, brake thermal efficiency, reduced bsfc and smoke opacity with favourable p-{theta} diagram as compared to diesel. (author)

  7. Biomedical device prototype based on small scale hydrodynamic cavitation

    Directory of Open Access Journals (Sweden)

    Morteza Ghorbani

    2018-03-01

    Full Text Available This study presents a biomedical device prototype based on small scale hydrodynamic cavitation. The application of small scale hydrodynamic cavitation and its integration to a biomedical device prototype is offered as an important alternative to other techniques, such as ultrasound therapy, and thus constitutes a local, cheap, and energy-efficient solution, for urinary stone therapy and abnormal tissue ablation (e.g., benign prostate hyperplasia (BPH. The destructive nature of bubbly, cavitating, flows was exploited, and the potential of the prototype was assessed and characterized. Bubbles generated in a small flow restrictive element (micro-orifice based on hydrodynamic cavitation were utilized for this purpose. The small bubbly, cavitating, flow generator (micro-orifice was fitted to a small flexible probe, which was actuated with a micromanipulator using fine control. This probe also houses an imaging device for visualization so that the emerging cavitating flow could be locally targeted to the desired spot. In this study, the feasibility of this alternative treatment method and its integration to a device prototype were successfully accomplished.

  8. Biomedical device prototype based on small scale hydrodynamic cavitation

    Science.gov (United States)

    Ghorbani, Morteza; Sozer, Canberk; Alcan, Gokhan; Unel, Mustafa; Ekici, Sinan; Uvet, Huseyin; Koşar, Ali

    2018-03-01

    This study presents a biomedical device prototype based on small scale hydrodynamic cavitation. The application of small scale hydrodynamic cavitation and its integration to a biomedical device prototype is offered as an important alternative to other techniques, such as ultrasound therapy, and thus constitutes a local, cheap, and energy-efficient solution, for urinary stone therapy and abnormal tissue ablation (e.g., benign prostate hyperplasia (BPH)). The destructive nature of bubbly, cavitating, flows was exploited, and the potential of the prototype was assessed and characterized. Bubbles generated in a small flow restrictive element (micro-orifice) based on hydrodynamic cavitation were utilized for this purpose. The small bubbly, cavitating, flow generator (micro-orifice) was fitted to a small flexible probe, which was actuated with a micromanipulator using fine control. This probe also houses an imaging device for visualization so that the emerging cavitating flow could be locally targeted to the desired spot. In this study, the feasibility of this alternative treatment method and its integration to a device prototype were successfully accomplished.

  9. Hydrodynamic cavitation: from theory towards a new experimental approach

    Science.gov (United States)

    Lucia, Umberto; Gervino, Gianpiero

    2009-09-01

    Hydrodynamic cavitation is analysed by a global thermodynamics principle following an approach based on the maximum irreversible entropy variation that has already given promising results for open systems and has been successfully applied in specific engineering problems. In this paper we present a new phenomenological method to evaluate the conditions inducing cavitation. We think this method could be useful in the design of turbo-machineries and related technologies: it represents both an original physical approach to cavitation and an economical saving in planning because the theoretical analysis could allow engineers to reduce the experimental tests and the costs of the design process.

  10. The issue of cavitation number value in studies of water treatment by hydrodynamic cavitation.

    Science.gov (United States)

    Šarc, Andrej; Stepišnik-Perdih, Tadej; Petkovšek, Martin; Dular, Matevž

    2017-01-01

    Within the last years there has been a substantial increase in reports of utilization of hydrodynamic cavitation in various applications. It has came to our attention that many times the results are poorly repeatable with the main reason being that the researchers put significant emphasis on the value of the cavitation number when describing the conditions at which their device operates. In the present paper we firstly point to the fact that the cavitation number cannot be used as a single parameter that gives the cavitation condition and that large inconsistencies in the reports exist. Then we show experiments where the influences of the geometry, the flow velocity, the medium temperature and quality on the size, dynamics and aggressiveness of cavitation were assessed. Finally we show that there are significant inconsistencies in the definition of the cavitation number itself. In conclusions we propose a number of parameters, which should accompany any report on the utilization of hydrodynamic cavitation, to make it repeatable and to enable faster progress of science and technology development. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Degradation of dichlorvos using hydrodynamic cavitation based treatment strategies.

    Science.gov (United States)

    Joshi, Ravi K; Gogate, Parag R

    2012-05-01

    The degradation of an aqueous solution of dichlorvos, a commonly used pesticide in India, has been systematically investigated using hydrodynamic cavitation reactor. All the experiments have been carried out using a 20 ppm solution of commercially available dichlorvos. The effect of important operating parameters such as inlet pressure (over a range 3-6 bar), temperature (31 °C, 36 °C and 39 °C) and pH (natural pH = 5.7 and acidic pH = 3) on the extent of degradation has been investigated initially. It has been observed that an optimum value of pressure gives maximum degradation whereas low temperature and pH of 3 are favorable. Intensification studies have been carried out using different additives such as hydrogen peroxide, carbon tetrachloride, and Fenton's reagent. Use of hydrogen peroxide and carbon tetrachloride resulted in the enhancement of the extent of degradation at optimized conditions but significant enhancement was obtained with the combined use of hydrodynamic cavitation and Fenton's chemistry. The maximum extent of degradation as obtained by using a combination of hydrodynamic cavitation and Fenton's chemistry was 91.5% in 1h of treatment time. The present work has conclusively established that hydrodynamic cavitation in combination with Fenton's chemistry can be effectively used for the degradation of dichlorvos. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Numerical simulation of the cavitation's hydrodynamic excitement

    International Nuclear Information System (INIS)

    Hassis, H.; Dueymes, E.; Lauro, J.F.

    1993-01-01

    First, we study the motion, the velocity, the phases plane and the acoustic sources associated to a spherical bubble in a compressible or incompressible medium. The bubble can be excited by periodic or random excitements. We study the parameters which influence their behaviour: periodicity or not of motion, implosion and explosion or oscillation of bubble. We take into account this behaviour in a model of cavitation: it is a numerical simulation using population of bubbles which are with positions (in the cavitation volume) and sizes are random. These bubbles are excited by a random excitement: a model of turbulent flow or implosion and explosion of bubble. (author)

  13. Large eddy simulation of hydrodynamic cavitation

    Science.gov (United States)

    Bhatt, Mrugank; Mahesh, Krishnan

    2017-11-01

    Large eddy simulation is used to study sheet to cloud cavitation over a wedge. The mixture of water and water vapor is represented using a homogeneous mixture model. Compressible Navier-Stokes equations for mixture quantities along with transport equation for vapor mass fraction employing finite rate mass transfer between the two phases, are solved using the numerical method of Gnanaskandan and Mahesh. The method is implemented on unstructured grid with parallel MPI capabilities. Flow over a wedge is simulated at Re = 200 , 000 and the performance of the homogeneous mixture model is analyzed in predicting different regimes of sheet to cloud cavitation; namely, incipient, transitory and periodic, as observed in the experimental investigation of Harish et al.. This work is supported by the Office of Naval Research.

  14. Degradation of BTEX in aqueous solution by hydrodynamic cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Braeutigam, P.; Wu, Z.-L.; Stark, A.; Ondruschka, B. [Institute for Technical Chemistry and Environmental Chemistry, Friedrich Schiller University, Jena (Germany)

    2009-05-15

    A self-made low-pressure device (up to 100 psi) for hydrodynamic cavitation was tested with the reaction of BTEX (benzene, toluene, ethylbenzene, and xylenes) in water. Experimental parameters, such as inlet pressure, solution temperature, and concentration of the chosen substrates, as well as the effect of different restrictions were investigated. The energy efficiency of the process was measured in comparison to two acoustic cavitation systems (24 and 850 kHz). The products of the BTEX degradation were identified and a pyrolytic degradation pathway is concluded. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  15. Degradation of organic wastewater by hydrodynamic cavitation combined with acoustic cavitation.

    Science.gov (United States)

    Yi, Chunhai; Lu, Qianqian; Wang, Yun; Wang, Yixuan; Yang, Bolun

    2018-05-01

    In this paper, the decomposition of Rhodamine B (RhB) by hydrodynamic cavitation (HC), acoustic cavitation (AC) and the combination of these individual methods (HAC) have been investigated. The degradation of 20 L RhB aqueous solution was carried out in a self-designed HAC reactor, where hydrodynamic cavitation and acoustic cavitation could take place in the same space simultaneously. The effects of initial concentration, inlet pressure, solution temperature and ultrasonic power were studied and discussed. Obvious synergies were found in the HAC process. The combined method achieved the best conversion, and the synergistic effect in HAC was even up to 119% with the ultrasonic power of 220 W in a treatment time of 30 min. The time-independent synergistic factor based on rate constant was introduced and the maximum value reached 40% in the HAC system. Besides, the hybrid HAC method showed great superiority in energy efficiency at lower ultrasonic power (88-176 W). Therefore, HAC technology can be visualized as a promising method for wastewater treatment with good scale-up possibilities. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Observation of chemiluminescence induced by hydrodynamic cavitation in microchannels.

    Science.gov (United States)

    Podbevsek, D; Colombet, D; Ledoux, G; Ayela, F

    2018-05-01

    We have performed hydrodynamic cavitation experiments with an aqueous luminol solution as the working fluid. Light emission, together with the high frequency noise which characterizes cavitation, was emitted by the two-phase flow, whereas no light emission from luminol was recorded in the single phase liquid flow. Light emission occurs downstream transparent microdiaphragms. The maximum level of the recorded signal was around 180 photons per second with flow rates of 380 µl/s, that corresponds to a real order of magnitude of the chemiluminescence of 75,000 photons per second. The yield of emitted photons increases linearly with the pressure drop, which is proportional to the square of the total flow rate. Chemiluminescence of luminol is a direct and a quantitative demonstration of the presence of OH hydroxyl radicals created by hydrodynamic cavitation. The presented method could be a key to optimize channel geometry for processes where radical production is essential. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Degradation of alachlor in aqueous solution by using hydrodynamic cavitation.

    Science.gov (United States)

    Wang, Xikui; Zhang, Yong

    2009-01-15

    The degradation of alachlor aqueous solution by using hydrodynamic cavitation was systematically investigated. It was found that alachlor in aqueous solution can be deomposed with swirling jet-induced cavitation. The degradation can be described by a pseudo-first-order kinetics and the degradation rate was found to be 4.90x10(-2)min(-1). The effects of operating parameters such as fluid pressure, solution temperature, initial concentration of alachlor and medium pH on the degradation rates of alachlor were also discussed. The results showed that the degradation rates of alachlor increased with increasing pressure and decreased with increasing initial concentration. An optimum temperature of 40 degrees C existed for the degradation rate of alachlor and the degradation rate was also found to be slightly depend on medium pH. Many degradation products formed during the process, and some of them were qualitatively identified by GC-MS.

  18. Interaction mechanism of double bubbles in hydrodynamic cavitation

    Science.gov (United States)

    Li, Fengchao; Cai, Jun; Huai, Xiulan; Liu, Bin

    2013-06-01

    Bubble-bubble interaction is an important factor in cavitation bubble dynamics. In this paper, the dynamic behaviors of double cavitation bubbles driven by varying pressure field downstream of an orifice plate in hydrodynamic cavitation reactor are examined. The bubble-bubble interaction between two bubbles with different radii is considered. We have shown the different dynamic behaviors between double cavitation bubbles and a single bubble by solving two coupling nonlinear equations using the Runge-Kutta fourth order method with adaptive step size control. The simulation results indicate that, when considering the role of the neighbor smaller bubble, the oscillation of the bigger bubble gradually exhibits a lag in comparison with the single-bubble case, and the extent of the lag becomes much more obvious as time goes by. This phenomenon is more easily observed with the increase of the initial radius of the smaller bubble. In comparison with the single-bubble case, the oscillation of the bigger bubble is enhanced by the neighbor smaller bubble. Especially, the pressure pulse of the bigger bubble rises intensely when the sizes of two bubbles approach, and a series of peak values for different initial radii are acquired when the initial radius ratio of two bubbles is in the range of 0.9˜1.0. Although the increase of the center distance between two bubbles can weaken the mutual interaction, it has no significant influence on the enhancement trend. On the one hand, the interaction between two bubbles with different radii can suppress the growth of the smaller bubble; on the other hand, it also can enhance the growth of the bigger one at the same time. The significant enhancement effect due to the interaction of multi-bubbles should be paid more attention because it can be used to reinforce the cavitation intensity for various potential applications in future.

  19. Hydrodynamic cavitation as a novel approach for delignification of wheat straw for paper manufacturing.

    Science.gov (United States)

    Badve, Mandar P; Gogate, Parag R; Pandit, Aniruddha B; Csoka, Levente

    2014-01-01

    The present work deals with application of hydrodynamic cavitation for intensification of delignification of wheat straw as an essential step in the paper manufacturing process. Wheat straw was first treated with potassium hydroxide (KOH) for 48 h and subsequently alkali treated wheat straw was subjected to hydrodynamic cavitation. Hydrodynamic cavitation reactor used in the work is basically a stator and rotor assembly, where the rotor is provided with indentations and cavitational events are expected to occur on the surface of rotor as well as within the indentations. It has been observed that treatment of alkali treated wheat straw in hydrodynamic cavitation reactor for 10-15 min increases the tensile index of the synthesized paper sheets to about 50-55%, which is sufficient for paper board manufacture. The final mechanical properties of the paper can be effectively managed by controlling the processing parameters as well as the cavitational parameters. It has also been established that hydrodynamic cavitation proves to be an effective method over other standard digestion techniques of delignification in terms of electrical energy requirements as well as the required time for processing. Overall, the work is first of its kind application of hydrodynamic cavitation for enhancing the effectiveness of delignification and presents novel results of significant interest to the paper and pulp industry opening an entirely new area of application of cavitational reactors. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. 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.

  1. Limitations of the Weissler reaction as a model reaction for measuring the efficiency of hydrodynamic cavitation.

    Science.gov (United States)

    Morison, K R; Hutchinson, C A

    2009-01-01

    The Weissler reaction in which iodide is oxidised to a tri-iodide complex (I(3)(-)) has been widely used for measurement of the intensity of ultrasonic and hydrodynamic cavitation. It was used in this work to compare ultrasonic cavitation at 24 kHz with hydrodynamic cavitation using two different devices, one a venturi and the other a sudden expansion, operated up to 8.7 bar. Hydrodynamic cavitation had a maximum efficiency of about 5 x 10(-11) moles of I(3)(-) per joule of energy compared with the maximum of almost 8 x 10(-11) mol J(-1) for ultrasonic cavitation. Hydrodynamic cavitation was found to be most effective at 10 degrees C compared with 20 degrees C and 30 degrees C and at higher upstream pressures. However, it was found that in hydrodynamic conditions, even without cavitation, I(3)(-) was consumed at a rapid rate leading to an equilibrium concentration. It was concluded that the Weissler reaction was not a good model reaction for the assessment of the effectiveness of hydrodynamic cavitation.

  2. Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems

    Science.gov (United States)

    Ferrari, A.

    2017-03-01

    Cavitation is the transition from a liquid to a vapour phase, due to a drop in pressure to the level of the vapour tension of the fluid. Two kinds of cavitation have been reviewed here: acoustic cavitation and hydrodynamic cavitation. As acoustic cavitation in engineering systems is related to the propagation of waves through a region subjected to liquid vaporization, the available expressions of the sound speed are discussed. One of the main effects of hydrodynamic cavitation in the nozzles and orifices of hydraulic power systems is a reduction in flow permeability. Different discharge coefficient formulae are analysed in this paper: the Reynolds number and the cavitation number result to be the key fluid dynamical parameters for liquid and cavitating flows, respectively. The latest advances in the characterization of different cavitation regimes in a nozzle, as the cavitation number reduces, are presented. The physical cause of choked flows is explained, and an analogy between cavitation and supersonic aerodynamic flows is proposed. The main approaches to cavitation modelling in hydraulic power systems are also reviewed: these are divided into homogeneous-mixture and two-phase models. The homogeneous-mixture models are further subdivided into barotropic and baroclinic models. The advantages and disadvantages of an implementation of the complete Rayleigh-Plesset equation are examined.

  3. Combined treatment technology based on synergism between hydrodynamic cavitation and advanced oxidation processes.

    Science.gov (United States)

    Gogate, Parag R; Patil, Pankaj N

    2015-07-01

    The present work highlights the novel approach of combination of hydrodynamic cavitation and advanced oxidation processes for wastewater treatment. The initial part of the work concentrates on the critical analysis of the literature related to the combined approaches based on hydrodynamic cavitation followed by a case study of triazophos degradation using different approaches. The analysis of different combinations based on hydrodynamic cavitation with the Fenton chemistry, advanced Fenton chemistry, ozonation, photocatalytic oxidation, and use of hydrogen peroxide has been highlighted with recommendations for important design parameters. Subsequently degradation of triazophos pesticide in aqueous solution (20 ppm solution of commercially available triazophos pesticide) has been investigated using hydrodynamic cavitation and ozonation operated individually and in combination for the first time. Effect of different operating parameters like inlet pressure (1-8 bar) and initial pH (2.5-8) have been investigated initially. The effect of addition of Fenton's reagent at different loadings on the extent of degradation has also been investigated. The combined method of hydrodynamic cavitation and ozone has been studied using two approaches of injecting ozone in the solution tank and at the orifice (at the flow rate of 0.576 g/h and 1.95 g/h). About 50% degradation of triazophos was achieved by hydrodynamic cavitation alone under optimized operating parameters. About 80% degradation of triazophos was achieved by combination of hydrodynamic cavitation and Fenton's reagent whereas complete degradation was achieved using combination of hydrodynamic cavitation and ozonation. TOC removal of 96% was also obtained for the combination of ozone and hydrodynamic cavitation making it the best treatment strategy for removal of triazophos. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Removal of Microcystis aeruginosa using hydrodynamic cavitation: performance and mechanisms.

    Science.gov (United States)

    Li, Pan; Song, Yuan; Yu, Shuili

    2014-10-01

    Algal blooms are a seasonal problem in eutrophic water bodies, and novel approaches to algal removal are required. The effect of hydrodynamic cavitation (HC) on the removal of Microcystis aeruginosa was investigated using a laboratory scale device. Samples treated by HC were subsequently grown under illuminated culture conditions. The results demonstrated that a short treatment with HC could effectively settle naturally growing M. aeruginosa without breaking cells. Algal cell density and chlorophyll-a of a sample treated for 10 min were significantly decreased by 88% andv 94%, respectively, after 3 days culture. Various HC operating parameters were investigated, showing that inhibition of M. aeruginosa growth mainly depended on treatment time and pump pressure. Electron microscopy confirmed that sedimentation of algae was attributable to the disruption of intracellular gas vesicles. Damage to the photosynthetic apparatus also contributed to the inhibition of algal growth. Free radicals produced by the cavitation process could be as an indirect indicator of the intensity of HC treatment, although they inflicted minimal damage on the algae. In conclusion, we suggest that HC represents a potentially highly effective and sustainable approach to the removal of algae from water systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    NARCIS (Netherlands)

    Rooze, J.; André, M.; van der Gulik, G-J.S.; Fernandez Rivas, David; Gardeniers, Johannes 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

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

    NARCIS (Netherlands)

    Rooze, J.; Andre, M.; Gulik, van der G.J.S.; Fernandez-Rivas, D.; Gardeniers, J.G.E.; Rebrov, E.; 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

  7. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Effect of hydrodynamic cavitation on the rate of OH-radical formation in the presence of hydrogen peroxide

    Science.gov (United States)

    Aseev, D. G.; Batoeva, A. A.

    2014-01-01

    It is shown experimentally that hydrogen peroxide is the source of OH-radicals at low-pressure hydrodynamic cavitation. Major preconditions for the intensification of oxidative destruction processes in organic pollutants with an added cavitation stimulus are determined.

  9. 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.

    by individual oscillating cavity, cell wall strength and geometrical and operating parameters of cavitation device. Theoretical model for quantifying the cavitationally generated turbulent shear and extent of microbial disinfection has been developed...

  10. Oxidation of alkylarenes to the corresponding acids using aqueous potassium permanganate by hydrodynamic cavitation.

    Science.gov (United States)

    Ambulgekar, G V; Samant, S D; Pandit, A B

    2004-05-01

    Oxidation of toluene using aqueous potassium permanganate was studied under heterogeneous condition in the presence of hydrodynamic cavitation and compared with the results of the reaction under acoustic cavitation. Various parameters, such as quantity of potassium permanganate, toluene to aqueous phase ratio, reaction time and cavitation parameters such as orifice plate, and pump discharge pressure were optimized. The reaction was found to be considerably accelerated at ambient temperature in the presence of cavitation. On comparison, it was found that when 1 kJ of energy was passed to the reaction mixture in the case of acoustic cavitation, the product obtained was 4.63 x 10(-6) mol, whereas when 1 kJ of energy was passed to the reaction mixture in the case of hydrodynamic cavitation the product obtained was 2.70 x 10(-5) mol. Hence, about six times more product would be obtained in the case of hydrodynamic cavitation than in the case of acoustic cavitation at same energy dissipation. It has been observed that further optimization is possible.

  11. Efficient inactivation of MS-2 virus in water by hydrodynamic cavitation.

    Science.gov (United States)

    Kosel, Janez; Gutiérrez-Aguirre, Ion; Rački, Nejc; Dreo, Tanja; Ravnikar, Maja; Dular, Matevž

    2017-11-01

    The aim of this study was to accurately quantify the impact of hydrodynamic cavitation on the infectivity of bacteriophage MS2, a norovirus surrogate, and to develop a small scale reactor for testing the effect of hydrodynamic cavitation on human enteric viruses, which cannot be easily prepared in large quantities. For this purpose, 3 mL scale and 1 L scale reactors were constructed and tested. Both devices were efficient in generating hydrodynamic cavitation and in reducing the infectivity of MS2 virus. Furthermore, they reached more than 4 logs reductions of viral infectivity, thus confirming the scalability of hydrodynamic cavitation for this particular application. As for the mechanism of page inactivation, we suspect that cavitation generated OH - radicals formed an advanced oxidation process, which could have damaged the host's recognition receptors located on the surface of the bacteriophage. Additional damage could arise from the high shear forces inside the cavity. Moreover, the effectiveness of the cavitation was higher for suspensions containing low initial viral titers that are in similar concentration to the ones found in real water samples. According to this, cavitation generators could prove to be a useful tool for treating virus-contaminated wastewaters in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Kidney stone erosion by micro scale hydrodynamic cavitation and consequent kidney stone treatment.

    Science.gov (United States)

    Perk, Osman Yavuz; Şeşen, Muhsincan; Gozuacik, Devrim; Koşar, Ali

    2012-09-01

    The objective of this study is to reveal the potential of micro scale hydrodynamic bubbly cavitation for the use of kidney stone treatment. Hydrodynamically generated cavitating bubbles were targeted to the surfaces of 18 kidney stone samples made of calcium oxalate, and their destructive effects were exploited in order to remove kidney stones in in vitro experiments. Phosphate buffered saline (PBS) solution was used as the working fluid under bubbly cavitating conditions in a 0.75 cm long micro probe of 147 μm inner diameter at 9790 kPa pressure. The surface of calcium oxalate type kidney stones were exposed to bubbly cavitation at room temperature for 5 to 30 min. The eroded kidney stones were visually analyzed with a high speed CCD camera and using SEM (scanning electron microscopy) techniques. The experiments showed that at a cavitation number of 0.017, hydrodynamic bubbly cavitation device could successfully erode stones with an erosion rate of 0.31 mg/min. It was also observed that the targeted application of the erosion with micro scale hydrodynamic cavitation may even cause the fracture of the kidney stones within a short time of 30 min. The proposed treatment method has proven to be an efficient instrument for destroying kidney stones.

  13. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Application of hydrodynamic cavitation in ballast water treatment.

    Science.gov (United States)

    Cvetković, Martina; Kompare, Boris; Klemenčič, Aleksandra Krivograd

    2015-05-01

    Ballast water is, together with hull fouling and aquaculture, considered the most important factor of the worldwide transfer of invasive non-indigenous organisms in aquatic ecosystems and the most important factor in European Union. With the aim of preventing and halting the spread of the transfer of invasive organisms in aquatic ecosystems and also in accordance with IMO's International Convention for the Control and Management of Ships Ballast Water and Sediments, the systems for ballast water treatment, whose work includes, e.g. chemical treatment, ozonation and filtration, are used. Although hydrodynamic cavitation (HC) is used in many different areas, such as science and engineering, implied acoustics, biomedicine, botany, chemistry and hydraulics, the application of HC in ballast water treatment area remains insufficiently researched. This paper presents the first literature review that studies lab- and large-scale setups for ballast water treatment together with the type-approved systems currently available on the market that use HC as a step in their operation. This paper deals with the possible advantages and disadvantages of such systems, as well as their influence on the crew and marine environment. It also analyses perspectives on the further development and application of HC in ballast water treatment.

  15. The synthesis of nanostructured, phase pure catalysts by hydrodynamic cavitation

    Energy Technology Data Exchange (ETDEWEB)

    Moser, W.R.; Sunstrom, J.E.; Marshik-Geurts, B.J. [Worcester Polytechnic Institute, Worcester, MA (United States)

    1995-12-01

    A new process for the synthesis of advanced catalytic materials based on performing the synthesis under hydrodynamic cavitation conditions has been discovered. This continuous process for catalyst synthesis resulted in the formation of both supported and unsupported catalysts. The advantage of the process over classical methods of synthesis is that it permits the formation of a wide variety of nanostructured catalysts in exceptionally high phase purities. The synthesis of platinum and palladium catalysts supported on alumina and other supports resulted in high dispersions of the noble metals. The synthesis of alpha, beta- and gamma-bismuth molybdates resulted in catalysts having superior phase purities as compared to several other classical methods of synthesis. The beta-bismuth molybdate was synthesized directly onto Cabosil. These studies showed that the particle size of the active component could be varied from a few manometers to much larger grains. The process enabled the synthesis of other complex metal oxides like perovskites as pure phases. The process uses a commercially available Microfluidizer.

  16. Intensification of esterification of acids for synthesis of biodiesel using acoustic and hydrodynamic cavitation.

    Science.gov (United States)

    Kelkar, Mandar A; Gogate, Parag R; Pandit, Aniruddha B

    2008-03-01

    Cavitation results in conditions of turbulence and liquid circulation in the reactor which can aid in eliminating mass transfer resistances. The present work illustrates the use of cavitation for intensification of biodiesel synthesis (esterification) reaction, which is mass transfer limited reaction considering the immiscible nature of the reactants, i.e., fatty acids and alcohol. Esterification of fatty acid (FA) odour cut (C(8)-C(10)) with methanol in the presence of concentrated H(2)SO(4) as a catalyst has been studied in hydrodynamic cavitation reactor as well as in the sonochemical reactor. The different reaction operating parameters such as molar ratio of acid to alcohol, catalyst quantity have been optimized under acoustic as well as hydrodynamic cavitating conditions in addition to the optimization of the geometry of the orifice plate in the case of hydrodynamic cavitation reactors. Few experiments have also been carried out with other acid (lower and higher)/methanol combination viz. caprylic acid and capric acids with methanol with an aim of investigating the efficacy of cavitation for giving the desired yields and also to quantify the degree of process intensification that can be achieved using the same. It has been observed that ambient operating conditions of temperature and pressure and reaction times of 90% conversion (mol%). This clearly establishes the efficacy of cavitation as an excellent way to achieve process intensification of the biodiesel synthesis process.

  17. Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Man; Lee, Seung Won; Park, Seong Dae; Kang, Sa Rah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2012-05-15

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

  18. Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Man; Lee, Seung Won; Park, Sung Dae; Kang, Sarah; Seo, Han; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2011-10-15

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

  19. Investigation on Hydrodynamic Cavitation of a Restriction Orifice and Static Mixer on Crud-like Deposits

    International Nuclear Information System (INIS)

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

    2012-01-01

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core have shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice and static mixer fundamentally

  20. Effects of Hydrodynamic Cavitation of a Restriction Orifice on Crud-like Deposits

    International Nuclear Information System (INIS)

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

    2011-01-01

    Axial Offset Anomaly (AOA) referring to an unexpected neutron flux depression is also known as Crud Induced Power Shift (CIPS). Fuel assemblies removed from an AOA core has shown a thick porous deposition layer of crud on fuel clad surface. The deposition layer was induced by precipitation reactions of both boron species and crud during sub-cooled nucleate boiling. Therefore, to resolve the AOA issues, a fuel cleaning technology using ultrasonic cavitation has been developed by EPRI and applied to the domestic NPPs by KNF. However, the performance of crud removal during maintenance of NPPs is known to be not enough. Hydrodynamic cavitation is the process of vaporization, bubble generation and bubble implosion which occurs in a flowing liquid as a result of decrease and subsequent increase in pressure. Hydrodynamic cavitation generates shock pressure of a few tens MPa due to bubble collapse like the cavitation generated by Ultrasonics. It is well known that the cavitation can erode the metal surface. The idea of the current study is that such energetic cavitation bubble collapses could help to remove the crud from the fuel assembly. Therefore, the current study first investigates effects of hydrodynamic cavitation occurred from a single hole orifice fundamentally

  1. 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

    2006-06-05

    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. Copyright 2006 Wiley Periodicals, Inc.

  2. Hydrodynamic cavitation in Stokes flow of anisotropic fluids

    OpenAIRE

    Stieger, Tillmann; Agha, Hakam; Schoen, Martin; Mazza, Marco G.; Sengupta, Anupam

    2017-01-01

    Cavitation, the nucleation of vapour in liquids, is ubiquitous in fluid dynamics, and is often implicated in a myriad of industrial and biomedical applications. Although extensively studied in isotropic liquids, corresponding investigations in anisotropic liquids are largely lacking. Here, by combining liquid crystal microfluidic experiments, nonequilibrium molecular dynamics simulations and theoretical arguments, we report flow-induced cavitation in an anisotropic fluid. The cavitation domai...

  3. Killing rate of colony count by hydrodynamic cavitation due to square multi-orifice plates

    Science.gov (United States)

    Dong, Zhiyong; Zhao, Wenqian

    2018-02-01

    Currently,in water supply engineering, the conventional technique of disinfection by chlorination is employed to kill pathogenic microorganisms in raw water. However, chlorine reacts with organic compounds in water and generates disinfection byproducts (DBPs), such as trihalomethanes (THMs), haloacetic acids (HAAs) etc. These byproducts are of carcinogenic, teratogenic and mutagenic effects, which seriously threaten human health. Hydrodynamic cavitation is a novel technique of drinking water disinfection without DBPs. Effects of orifice size, orifice number and orifice layout of multi-orifice plate, cavitation number, cavitation time and orifice velocity on killing pathogenic microorganisms by cavitation were investigated experimentally in a self-developed square multi-orifice plate-type hydrodynamic cavitation device. The experimental results showed that cavitation effects increased with decrease in orifice size and increase in orifice number, cavitation time and orifice velocity. Along with lowering in cavitation number, there was an increase in Reynolds shear stress,thus enhancing the killing rate of pathogenic microorganism in raw water. In addition, the killing rate by staggered orifice layout was greater than that by checkerboard-type orifice layout.

  4. Comparison of Nannochloropsis sp. cells disruption between hydrodynamic cavitation and conventional extraction

    Directory of Open Access Journals (Sweden)

    Setyawan Martomo

    2018-01-01

    Full Text Available Biodiesel production from microalgae is one of the solution of the future energy problem, but its production cost is still high. One of the costly stages of this process is the lipid extraction process. It can be reduced by microalgae cell disruption. One of the mechanical method to cell disruption with the lowest energy requirement is hydrodynamic cavitation. This aim of this study is to evaluate the distribution coefficient and the mass transfer coefficient value of lipid extraction of Nannochloropsis sp. assisted by hydrodynamic cavitation and compare with conventional extraction. The hydrodynamic cavitation extraction was done at 34 °C, 1 atm. The conventional extraction was done at 34 °C, 1 atm with stirring speed 260 and 1000 rpm. The experimental result shows that the distribution coefficient dependent on the temperature with the values for 50, 44, 38 and 34 °C were 0.502, 0.394, 0.349, and 0.314 respectively. And it was according to Van’ Hoff equation with the values of ΔH° was 20.718 kJ/mol and ΔS° was 58.05 J/mol/K. The hydrodynamic cavitation extraction was faster than conventional. The mass transfer coefficient values for hydrodynamic cavitation, conventional 260 rpm and 1000 rpm were 7.373, 0.534 and 0.121 1/s respectively.

  5. A parametrical study of disinfection with hydrodynamic cavitation.

    Science.gov (United States)

    Arrojo, S; Benito, Y; Tarifa, A Martínez

    2008-07-01

    The physical and chemical conditions generated by cavitation bubbles can be used to destroy microorganisms and disinfect wastewater. The effect of different cavitation chamber designs and diverse operational parameters on the inactivation rate of Escherichia coli have been studied and used to understand the mechanisms involved in cell disruption.

  6. 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%.

  7. Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

    OpenAIRE

    Mahlinda, Mahlinda; Djafar, Fitriana

    2014-01-01

    Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC....

  8. 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

  9. Study of physical and biological factors involved in the disruption of E. coli by hydrodynamic cavitation.

    Science.gov (United States)

    Balasundaram, B; Harrison, S T L

    2006-01-01

    Hydrodynamic cavitation results in flow restriction in a flow system causing rapid pressure fluctuations and significant fluid forces. These can be harnessed to mediate microbial cell damage. Hydrodynamic cavitation was studied for the partial disruption of E. coli and selective release of specific proteins relative to the total soluble protein. The effects of the cavitation number, the number of passes, and the specific growth rate of E. coli on the release of periplasmic and cytoplasmic proteins were studied. At the optimum cavitation number of 0.17 for this experimental configuration, 48% of the total soluble protein, 88% of acid phosphatase, and 67% of beta-galactosidase were released by hydrodynamic cavitation in comparison with the maximum release attained using multiple passes through the French Press. The higher release of the acid phosphatase over the total soluble protein suggested preferred release of periplasmic compounds. This was supported by SDS-PAGE analysis. The absence of micronization of cell material resulting in the potential for ease of solid-liquid separation downstream of the cell disruption operation was confirmed by TEM microscopy. E. coli cells cultivated at a higher specific growth rate (0.36 h(-1)) were more easily disrupted than slower grown cells (0.11 h(-1)). The specific activity of the enzyme of interest released by hydrodynamic cavitation, defined as the units of enzyme in solution per milligram of total soluble protein, was greater than that obtained on release by the French Press, high-pressure homogenization, osmotic shock, and EDTA treatment. The selectivity offered indicates the potential of enzyme release by hydrodynamic cavitation to ease the purification in the subsequent downstream processing.

  10. Study on transient hydrodynamic performance and cavitation characteristic of high-speed mixed-flow pump

    International Nuclear Information System (INIS)

    Chen, T; Liu, Y L; Sun, Y B; Wang, L Q; Wu, D Z

    2013-01-01

    In order to analyse the hydrodynamic performance and cavitation characteristic of a high-speed mixed-flow pump during transient operations, experimental studies were carried out. The transient hydrodynamic performance and cavitation characteristics of the mixed-flow pump with guide vane during start-up operation processes were tested on the pump performance test-bed. Performance tests of the pump were carried out under various inlet pressures and speed-changing operations. The real-time instantaneous external characteristics such as rotational speed, hydraulic head, flow rate, suction pressure and discharge pressure of the pump were measured. Based on the experimental results, the effect of fluid acceleration on the hydrodynamic performances and cavitation characteristics of the mixed-flow pump were analysed and evaluated

  11. Influence of the bubbles on the turbulence in the liquid in hydrodynamic cavitation through a venturi

    Science.gov (United States)

    Fuzier, Sylvie; Coutier Delgosha, Olivier; Coudert, S. Ébastien; Dazin, Antoine

    2011-11-01

    The physical description of hydrodynamic cavitation is complex as it includes strongly unsteady, turbulent and phase change phenomena. Because the bubbles in the cavitation area render this zone opaque, nonintrusive experimental observation inside this zone is difficult and little is known about the detailed bubble, flow structure and physics inside. A novel approach using LIF-PIV to investigate the dynamics inside the cavitation area generated through a venturi is presented. The velocity in the liquid and of the bubbles are measured simultaneously and correlated with areas of various bubble structure. The influence of the bubble structure on the turbulence in the liquid is also studied.

  12. A simple process to achieve microchannels geometries able to produce hydrodynamic cavitation

    Science.gov (United States)

    Qiu, X.; Cherief, W.; Colombet, D.; Ayela, F.

    2017-04-01

    We present a simple process to perform microchannels in which cavitating two phase flows are easily producible. Up to now, hydrodynamic cavitation ‘on a chip’ was reached with small flow rates inside microchannels whose micromachining had involved a deep reactive ion etching (D-RIE). The process we present here does not require a D-RIE reactor, as it is only funded on a wet etching of silicon. It leads to a so-called microstep profile, and large cavitating flow rates become possible together with moderate pressure drops.

  13. CFD analysis of the hydrodynamic and cavitation performances of modified NACA 4418 hydrofoil

    International Nuclear Information System (INIS)

    Markov, Zoran; Popovski, Predrag; Lipej, Andrej

    2001-01-01

    The paper presents the analysis of the possibilities of using Computational Fluid Dynamics technology for calculating of the flow parameters in a cavitation tunnel. Different turbulence models are used to perform the calculations. Comparison of the results from the experimental work and the CFD-TASC flow analysis are presented. Cavitation is addressed as a particular phenomenon, but also its influence on the hydrodynamic parameters. Constant enthalpy vaporization model is used for this purpose and the results will be compared with the photos taken during the cavitation investigation in the tunnel. (Original)

  14. A simple process to achieve microchannels geometries able to produce hydrodynamic cavitation

    International Nuclear Information System (INIS)

    Qiu, X; Cherief, W; Colombet, D; Ayela, F

    2017-01-01

    We present a simple process to perform microchannels in which cavitating two phase flows are easily producible. Up to now, hydrodynamic cavitation ‘on a chip’ was reached with small flow rates inside microchannels whose micromachining had involved a deep reactive ion etching (D-RIE). The process we present here does not require a D-RIE reactor, as it is only funded on a wet etching of silicon. It leads to a so-called microstep profile, and large cavitating flow rates become possible together with moderate pressure drops. (technical note)

  15. Luminescence from hydrodynamic cavitation. Method and preliminary analysis

    Energy Technology Data Exchange (ETDEWEB)

    Leighton, T.; Farhat, M.; Field, J. [and others

    2001-06-01

    This report describes a photon-counting study of the cavitation luminescence produced by flow over a hydrofoil. The object was to obtain quantitative data on the number of photons emitted for various flow conditions and to study the link between the light output and the potential for cavitation damage. The flow experiments were performed in a cavitation tunnel capable of achieving flow velocities of up to ca. 50 m s{sup -1} in the test sections. The experimental hydrofoil was a NACA 009 blade. Parameters varied were the flow velocity, the incident angle of the hydrofoil and the cavitation index. The results show that significant photon counts are recorded when leading edge cavitation takes place and U-shaped vortices (cavities) shed from the main cavity. The photon count increases dramatically as the flow velocity increases or the cavitation index is reduced. Departure from a Poisson distribution in the arrival times of photons at the detector may be related to the way vortices shed from the main cavity. Finally, there is a clear correlation between light output and the conditions which could cause cavitation damage. (author)

  16. Luminescence from hydrodynamic cavitation. Method and preliminary analysis

    International Nuclear Information System (INIS)

    Leighton, T.; Farhat, M.; Field, J.

    2001-01-01

    This report describes a photon-counting study of the cavitation luminescence produced by flow over a hydrofoil. The object was to obtain quantitative data on the number of photons emitted for various flow conditions and to study the link between the light output and the potential for cavitation damage. The flow experiments were performed in a cavitation tunnel capable of achieving flow velocities of up to ca. 50 m s -1 in the test sections. The experimental hydrofoil was a NACA 009 blade. Parameters varied were the flow velocity, the incident angle of the hydrofoil and the cavitation index. The results show that significant photon counts are recorded when leading edge cavitation takes place and U-shaped vortices (cavities) shed from the main cavity. The photon count increases dramatically as the flow velocity increases or the cavitation index is reduced. Departure from a Poisson distribution in the arrival times of photons at the detector may be related to the way vortices shed from the main cavity. Finally, there is a clear correlation between light output and the conditions which could cause cavitation damage. (author)

  17. Inactivation of Heterosigma akashiwo in ballast water by circular orifice plate-generated hydrodynamic cavitation.

    Science.gov (United States)

    Feng, Daolun; Zhao, Jie; Liu, Tian

    2016-01-01

    The discharge of alien ballast water is a well-known, major reason for marine species invasion. Here, circular orifice plate-generated hydrodynamic cavitation was used to inactivate Heterosigma akashiwo in ballast water. In comparison with single- and multihole orifice plates, the conical-hole orifice plate yielded the highest inactivation percentage, 51.12%, and consumed only 6.84% energy (based on a 50% inactivation percentage). Repeating treatment, either using double series-connection or circling inactivation, elevated the inactivation percentage, yet consumed much more energy. The results indicate that conical-hole-generated hydrodynamic cavitation shows great potential as a pre-inactivation method for ballast water treatment.

  18. Motion-sensitized SPRITE measurements of hydrodynamic cavitation in fast pipe flow.

    Science.gov (United States)

    Adair, Alexander; Mastikhin, Igor V; Newling, Benedict

    2018-06-01

    The pressure variations experienced by a liquid flowing through a pipe constriction can, in some cases, result in the formation of a bubble cloud (i.e., hydrodynamic cavitation). Due to the nature of the bubble cloud, it is ideally measured through the use of non-optical and non-invasive techniques; therefore, it is well-suited for study by magnetic resonance imaging. This paper demonstrates the use of Conical SPRITE (a 3D, centric-scan, pure phase-encoding pulse sequence) to acquire time-averaged void fraction and velocity information about hydrodynamic cavitation for water flowing through a pipe constriction. Copyright © 2018 Elsevier Inc. All rights reserved.

  19. A review and assessment of hydrodynamic cavitation as a technology for the future.

    Science.gov (United States)

    Gogate, Parag R; Pandit, Aniruddha B

    2005-01-01

    In the present work, the current status of the hydrodynamic cavitation reactors has been reviewed discussing the bubble dynamics analysis, optimum design considerations, design correlations for cavitational intensity (in terms of collapse pressure)/cavitational yield and different successful chemical synthesis applications clearly illustrating the utility of these types of reactors. The theoretical discussion based on the modeling of the bubble dynamics equations aims at understanding the design information related to the dependency of the cavitational intensity on the operating parameters and recommendations have been made for the choice of the optimized conditions of operating parameters. The design information based on the theoretical analysis has also been supported with some experimental illustrations concentrating on the chemical synthesis applications. Assessment of the hydrodynamic cavitation reactors and comparison with the sonochemical reactors has been done by citing the different industrially important reactions (oxidation of toluene, o-xylene, m-xylene, p-xylene, mesitylene, o-nitrotoluene, p-nitrotoluene, m-nitrotoluene, o-chlorotoluene and p-chlorotoulene, and trans-esterification reaction i.e., synthesis of bio-diesel). Some recommendations have also been made for the future work to be carried out as well as the choice of the operating conditions for realizing the dream of industrial scale applications of the cavitational reactors.

  20. Application of salicylic acid dosimetry to evaluate hydrodynamic cavitation as an advanced oxidation process.

    Science.gov (United States)

    Arrojo, S; Nerín, C; Benito, Y

    2007-03-01

    The generation of OH* radicals inside hydrodynamic cavitation bubbles was monitored using a salicylic acid dosimeter. The reaction of this scavenger with OH* produces 2,5-dihydroxybenzoic acid (2,5-DHB) and, to a lesser degree, 2,3-DHB. The former, is a specific reaction product that can be determined with a very high sensitivity using HPLC-IF. This method has been applied to study the influence of the flow-rate and the solution pH for a given cavitation chamber geometry. The salicylic dosimetry has proven especially suitable for the characteristic time scales of hydrodynamic cavitation (higher than those of ultrasonic cavitation), which usually gives rise to recombination of radicals before they can reach the liquid-phase. Working at low pH the hydrophobic salicylic acid migrates to the gas-liquid interface and reacts with the OH* radicals, increasing the trapping efficiency of the dosimeter. Hydrodynamic cavitation works as a very low frequency sonochemical reactor, and therefore its potential as an Advanced Oxidation Process might be limited to reactions at the gas-liquid interface and inner bubble (i.e. with volatiles and/or hydrophobic substances).

  1. Hydrodynamic Cavitation through “Labs on a Chip”: From Fundamentals to Applications

    Directory of Open Access Journals (Sweden)

    Ayela Frederic

    2017-07-01

    Full Text Available Monitoring hydrodynamic cavitation of liquids through “labs on a chip” (i.e. microchannels with a shrinkage, such as microdiaphragms or microventuris is an improvement in experimental approaches devoted to study the mechanisms involved in these multiphase flows. The small sizes of the reactors do not require big substructures. Flow rates of around 1 L/h make possible the characterisation of rare, toxic or expensive pure fluids or mixtures. Moreover, because of that microfluidic approach, an unique inception of the cavitation from a laminar flow regime is also possible, that provides precious databases for simulation or modelisation. Lastly, “labs on a chip” are an extremely versatile solution to perform novel experiments, as they are embeddable in tools basically designed to proceed with small samples (confocal microscopy, spectroscopy. We present here a summary of the former experiments performed by our team, concerning the fundamental aspects of hydrodynamic cavitation in a microchannel. We have recorded, with thermosensitive nanoparticles dispersed in water, the thermal signature of the growth and collapse of bubbles. We were also able to monitor the cavitation flow regime from a laminar single liquid phase. We are currently involved in applicative studies of hydrodynamic cavitation in microchannels, and preliminary results concerning liquid phase exfoliation of graphene will be also presented.

  2. Hydrodynamic cavitation in microsystems. II. Simulations and optical observations

    Science.gov (United States)

    Medrano, M.; Pellone, C.; Zermatten, P. J.; Ayela, F.

    2012-04-01

    Numerical calculations in the single liquid phase and optical observations in the two-phase cavitating flow regime have been performed on microdiaphragms and microventuris fed with deionized water. Simulations have confirmed the influence of the shape of the shrinkage upon the contraction of the jet, and so on the localisation of possible cavitating area downstream. Observations of cavitating flow patterns through hybrid silicon-pyrex microdevices have been performed either via a laser excitation with a pulse duration of 6 ns, or with the help of a high-speed camera. Recorded snapshots and movies are presented. Concerning microdiaphragms, it is confirmed that very high shear rates downstream the diaphragms are the cause of bubbly flows. Concerning microventuris, a gaseous cavity forms on a boundary downstream the throat. As a consequence of a microsystem instability, the cavity displays a high frequency pulsation. Low values Strouhal numbers are associated to such a sheet cavitation. Moreover, when the intensity of the cavitating flow is reduced, there is a mismatch between the frequency of the pulsation of the cavity and the frequency of shedded clouds downstream the channel. That may be the consequence of viscous effects limiting the impingement of a re-entrant liquid jet on the attached cavity.

  3. Numerical Modelling and Prediction of Erosion Induced by Hydrodynamic Cavitation

    Science.gov (United States)

    Peters, A.; Lantermann, U.; el Moctar, O.

    2015-12-01

    The present work aims to predict cavitation erosion using a numerical flow solver together with a new developed erosion model. The erosion model is based on the hypothesis that collapses of single cavitation bubbles near solid boundaries form high velocity microjets, which cause sonic impacts with high pressure amplitudes damaging the surface. The erosion model uses information from a numerical Euler-Euler flow simulation to predict erosion sensitive areas and assess the erosion aggressiveness of the flow. The obtained numerical results were compared to experimental results from tests of an axisymmetric nozzle.

  4. Application of hydrodynamic cavitation to improve the biodegradability of mature landfill leachate.

    Science.gov (United States)

    Bis, M; Montusiewicz, A; Ozonek, J; Pasieczna-Patkowska, S

    2015-09-01

    In this study, the application of hydrodynamic cavitation to improve the biodegradability of mature landfill leachate was investigated. Three configurations of cavitation device were examined and operational parameters of the process were selected. The study indicated that the orifice plate with a 3/10mm diameter conical concentric hole, characterized by the cavitation number of 0.033, is a reasonable choice to ensure the enhanced biodegradability of mature leachate. Using such a configuration and maintaining 30 recirculation passes through the cavitation zone at inlet pressure of 7 bar, the highest increase of biodegradability index (BI) of approximately 22% occurred, i.e., from the value of 0.046 to 0.056. The FT-IR/PAS analysis confirmed a degradation of refractory compounds that typically prevail in mature leachate. An evaluation of energy efficiency was made in terms of the actual consumed energy measured by using the Kyoritsu KEW6310 Power Quality Tester. A cavitational yield of 9.8 mg COD kJ(-1) was obtained for the optimum configuration and 30 recirculation passes. Regarding energy efficiency, the application of 10 cavitation cycles appeared to be the most profitable. This was due to an almost threefold higher cavitational yield of 27.5 mg COD kJ(-1). However, the preferable option should be selected by considering a satisfactory effect in the biodegradability enhancement. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Cavitation

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Cavitation in fluid machines or flow passages can cause loss of performance or material damage due to erosion. This conference reports the results of world-wide research into all aspects of the study of cavitation. Contents include: Cavitation effects in machinery such as pumps, water turbines, propellers and positive displacement machinery; Cavitation in structures, flow passages, valves, flow meters and bearings; Cavitation erosion, noise and instability effects; Cavitation inception; Developed flows; Supercavitating flows and machines; Fundamentals; Bubble dynamics and thermodynamics of cavitation in various fluids; Test facilities and methods of cavitation research and testing; Special instrumentation for cavitation studies, and standards and recommendations for cavitation or erosion

  6. Hydrodynamic cavitation in microsystems. I. Experiments with deionized water and nanofluids

    Science.gov (United States)

    Medrano, M.; Zermatten, P. J.; Pellone, C.; Franc, J. P.; Ayela, F.

    2011-12-01

    An experimental study of hydrodynamic cavitation downstream microdiaphragms and microventuris is presented. Deionized water and nanofluids have been characterized within silicon-Pyrex micromachined devices with hydraulic diameters ranging from 51 μm to 104 μm. The input pressure could reach up to 10 bars, and the flow rate was below 1 liter per hour. The output pressure of the devices was fixed at values ranging from 0.3 bar to 2 bars, so that it was possible to study the evolution of the cavitation number as a function of the Reynolds number in the orifice of the diaphragms or in the throat of the venturis. A delay on the onset of cavitation has been recorded for all the devices when they are fed with deionized water, because of the metastability of the liquid and because of the lack of roughness of the walls. For the first time, hydrodynamic cavitation of nanofluids (nanoparticles dispersed into the liquid) has been considered. The presence of nano-aggregates in the liquid does not exhibit any noticeable effect on the cavitation threshold through the venturis. However, such a presence has a strong influence on the cavitation onset in microdiaphragms: above a critical volume solid concentration of ≈10-5, the metastability is broken and the nanofluids behave as tap water filled up with large nuclei. These microdevices, where a low amount of fluid is required to reach cavitating flows, appear to be useful tools in order to study cavitating phenomena in localized area with specific fluids.

  7. Shear-induced hydrodynamic cavitation as a tool for pharmaceutical micropollutants removal from urban wastewater.

    Science.gov (United States)

    Zupanc, Mojca; Kosjek, Tina; Petkovšek, Martin; Dular, Matevž; Kompare, Boris; Širok, Brane; Stražar, Marjeta; Heath, Ester

    2014-05-01

    In this study, the removal of clofibric acid, ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac residues from wastewater, using a novel shear-induced cavitation generator has been systematically studied. The effects of temperature, cavitation time and H2O2 dose on removal efficiency were investigated. Optimisation (50°C; 15 min; 340 mg L(-1) of added H2O2) resulted in removal efficiencies of 47-86% in spiked deionised water samples. Treatment of actual wastewater effluents revealed that although matrix composition reduces removal efficiency, this effect can be compensated for by increasing H2O2 dose (3.4 g L(-1)) and prolonging cavitation time (30 min). Hydrodynamic cavitation has also been investigated as either a pre- or a post-treatment step to biological treatment. The results revealed a higher overall removal efficiency of recalcitrant diclofenac and carbamazepine, when hydrodynamic cavitation was used prior to as compared to post biological treatment i.e., 54% and 67% as compared to 39% and 56%, respectively. This is an important finding since diclofenac is considered as a priority substance to be included in the EU Water Framework Directive. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Disinfection of Escherichia coli bacteria using hybrid method of ozonation and hydrodynamic cavitation with orifice plate

    Science.gov (United States)

    Karamah, Eva F.; Ghaudenson, Rioneli; Amalia, Fitri; Bismo, Setijo

    2017-11-01

    This research aims to evaluate the performance of hybrid method of ozonation and hydrodynamic cavitation with orifice plate on E.coli bacteria disinfection. In this research, ozone dose, circulation flowrate, and disinfection method were varied. Ozone was produced by commercial ozonator with ozone dose of 64.83 mg/hour, 108.18 mg/hour, and 135.04 mg/hour. Meanwhile, hydrodynamic cavitation was generated by an orifice plate. The disinfection method compared in this research were: hydrodynamic cavitation, ozonation, and the combination of both. The best result on each method was achieved on the 60th minutes and with a circulation flowrate of 7 L/min. The hybrid method attained final concentration of 0 CFU/mL from the initial concentration of 2.10 × 105 CFU/mL. The ozonation method attained final concentration of 0 CFU/mL from the initial concentration of 1.32 × 105 CFU/mL. Cavitation method gives the least disinfection with final concentration of 5.20 × 104 CFU/mL from the initial concentration of 2.17 × 105 CFU/mL. In conclusion, hybrid method gives a faster and better disinfection of E.coli than each method on its own.

  9. A Non-catalytic Deep Desulphurization Process using Hydrodynamic Cavitation

    Science.gov (United States)

    Suryawanshi, Nalinee B.; Bhandari, Vinay M.; Sorokhaibam, Laxmi Gayatri; Ranade, Vivek V.

    2016-09-01

    A novel approach is developed for desulphurization of fuels or organics without use of catalyst. In this process, organic and aqueous phases are mixed in a predefined manner under ambient conditions and passed through a cavitating device. Vapor cavities formed in the cavitating device are then collapsed which generate (in-situ) oxidizing species which react with the sulphur moiety resulting in the removal of sulphur from the organic phase. In this work, vortex diode was used as a cavitating device. Three organic solvents (n-octane, toluene and n-octanol) containing known amount of a model sulphur compound (thiophene) up to initial concentrations of 500 ppm were used to verify the proposed method. A very high removal of sulphur content to the extent of 100% was demonstrated. The nature of organic phase and the ratio of aqueous to organic phase were found to be the most important process parameters. The results were also verified and substantiated using commercial diesel as a solvent. The developed process has great potential for deep of various organics, in general, and for transportation fuels, in particular.

  10. Preparation of biodiesel with the help of ultrasonic and hydrodynamic cavitation.

    Science.gov (United States)

    Ji, Jianbing; Wang, Jianli; Li, Yongchao; Yu, Yunliang; Xu, Zhichao

    2006-12-22

    An alkali-catalyzed biodiesel production method with power ultrasonic (19.7 kHz) has been developed that allows a short reaction time and high yield because of emulsification and cavitation of the liquid-liquid immiscible system. Orthogonality experiments were employed to evaluate the effects of synthesis parameters. Furthermore, hydrodynamic cavitation was used for biodiesel production in comparison to ultrasonic method. Both methods were proved to be efficient, and time and energy saving for the preparation of biodiesel by transesterification of soybean oil.

  11. Analysis on transient hydrodynamic characteristics of cavitation process for reactor coolant pump

    International Nuclear Information System (INIS)

    Wang Xiuli; Wang Peng; Yuan Shouqi; Zhu Rongsheng; Fu Qiang

    2014-01-01

    The reactor coolant pump hydrodynamic characteristics at different cavitation conditions were studied by using flow field analysis software ANSYS CFX, and the corresponding data were processed and analyzed by using Morlet wavelet transform and fast Fourier transform. The results show that gas content presents the law of exponential function with the pressure reduction or time increase. In the cavitation primary condition, the pulsation frequency of head for the reactor coolant pump is mainly low frequency, and the main frequency of pressure pulsation is still rotation frequency while the effect of the pressure pulsation caused by cavitation on main frequency is not obvious. With the development of cavitation, the pressure fluctuation induced by cavitation becomes more serious especially for the main frequency, secondary frequency and pulsating amplitude while the head pulsation frequency is given priority to low frequency pulse. Under serious cavitation condition, the head pulsation frequency is given priority to irregular changes of pulse high frequency, and also contains almost regular changes of low frequency. (authors)

  12. Applying the technology of hydrodynamic cavitation treatment of high-viscosity oils to increase the efficiency of transportation

    Science.gov (United States)

    Brand, A. E.; Vershinina, S. V.; Vengerov, A. A.; Mostovaya, N. A.

    2015-10-01

    The article investigates the possibility of applying hydrodynamic cavitation treatment to reduce oil viscosity in Russian pipeline transportation system and increase its performance. The result of laboratory tests and suggestions on technology application are given

  13. 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. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Inactivation of food spoilage microorganisms by hydrodynamic cavitation to achieve pasteurization and sterilization of fluid foods.

    Science.gov (United States)

    Milly, P J; Toledo, R T; Harrison, M A; Armstead, D

    2007-11-01

    Hydrodynamic cavitation is the formation of gas bubbles in a fluid due to pressure fluctuations induced by mechanical means. Various high-acid (pH hydrodynamic cavitation reactor to determine if commercial sterility can be achieved at reduced processing temperatures. Sporicidal properties of the process were also tested on a low-acid (pH > [corrected] 4.6) fluid food. Fluid foods were pumped under pressure into a hydrodynamic cavitation reactor and subjected to 2 rotor speeds and flow rates to achieve 2 designated exit temperatures. Thermal inactivation kinetics were used to determine heat-induced lethality for all organisms. Calcium-fortified apple juice processed at 3000 and 3600 rpm rotor speeds on the reactor went through a transient temperature change from 20 to 65.6 or 76.7 degrees C and the total process lethality exceeded 5-log reduction of Lactobacillus plantarum and Lactobacillus sakei cells, and Zygosaccharomyces bailii cells and ascospores. Tomato juice inoculated with Bacillus coagulans spores and processed at 3000 and 3600 rpm rotor speeds endured a transient temperature from 37.8 to 93.3 or 104.4 degrees C with viable CFU reductions of 0.88 and 3.10 log cycles, respectively. Skim milk inoculated with Clostridium sporogenes putrefactive anaerobe 3679 spores and processed at 3000 or 3600 rpm rotor speeds endured a transient temperature from 48.9 to 104.4 or 115.6 degrees C with CFU reductions of 0.69 and 2.84 log cycles, respectively. Utilizing hydrodynamic cavitation to obtain minimally processed pasteurized low-acid and commercially sterilized high-acid fluid foods is possible with appropriate process considerations for different products.

  15. Hydrodynamic Cavitation through “Labs on a Chip”: From Fundamentals to Applications

    OpenAIRE

    Ayela , Frederic; Cherief , Wahid; Colombet , Damien; Ledoux , Gilles; Martini , Mateo; Mossaz , Stephane; Podbevsek , Darjan; Qiu , Xiaoyu; Tillement , Olivier

    2017-01-01

    International audience; Monitoring hydrodynamic cavitation of liquids through “labs on a chip” (i.e. microchannels with a shrinkage, such as microdiaphragms or microventuris) is an improvement in experimental approaches devoted to study the mechanisms involved in these multiphase flows. The small sizes of the reactors do not require big substructures. Flow rates of around 1 L/h make possible the characterisation of rare, toxic or expensive pure fluids or mixtures. Moreover, because of that mi...

  16. Treatment of industrial wastewater effluents using hydrodynamic cavitation and the advanced Fenton process.

    Science.gov (United States)

    Chakinala, Anand G; Gogate, Parag R; Burgess, Arthur E; Bremner, David H

    2008-01-01

    For the first time, hydrodynamic cavitation induced by a liquid whistle reactor (LWR) has been used in conjunction with the advanced Fenton process (AFP) for the treatment of real industrial wastewater. Semi-batch experiments in the LWR were designed to investigate the performance of the process for two different industrial wastewater samples. The effect of various operating parameters such as pressure, H2O2 concentration and the initial concentration of industrial wastewater samples on the extent of mineralization as measured by total organic carbon (TOC) content have been studied with the aim of maximizing the extent of degradation. It has been observed that higher pressures, sequential addition of hydrogen peroxide at higher loadings and lower concentration of the effluent are more favourable for a rapid TOC mineralization. In general, the novel combination of hydrodynamic cavitation with AFP results in about 60-80% removal of TOC under optimized conditions depending on the type of industrial effluent samples. The combination described herein is most useful for treatment of bio-refractory materials where the diminution in toxicity can be achieved up to a certain level and then conventional biological oxidation can be employed for final treatment. The present work is the first to report the use of a hydrodynamic cavitation technique for real industrial wastewater treatment.

  17. Removal of blue-green algae using the hybrid method of hydrodynamic cavitation and ozonation.

    Science.gov (United States)

    Wu, Zhilin; Shen, Haifeng; Ondruschka, Bernd; Zhang, Yongchun; Wang, Weimin; Bremner, David H

    2012-10-15

    A suspension of Microcystis aeruginosa (30 μg L(-1)chlorophyll a) was circulated in a hydrodynamic cavitation device and ozone was introduced at the suction side of the pump. The removal of algae over 10 min using hydrodynamic cavitation alone and ozone alone is less than 15% and 35%, respectively. The destruction of algae rises significantly from 24% in the absence of the orifice to 91% with the optimized orifice on 5 min of processing using hydrodynamic cavitation along with ozone (HC/O(3)) and the utilization of ozone increases from 32% to 61%. Interestingly, the suction process is more effective than the extrusion method (positive pressure) and the optimal bulk temperature for algal elimination was found to be 20 °C. Increasing the input concentration of ozone is favorable for the removal of algae but leads to a greater loss of ozone and a decrease in the utilization of ozone. Under the optimal conditions, the algal cells and chlorophyll a are completely destroyed in 10 min by use of the hybrid method. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Degradation of reactive orange 4 dye using hydrodynamic cavitation based hybrid techniques.

    Science.gov (United States)

    Gore, Mohan M; Saharan, Virendra Kumar; Pinjari, Dipak V; Chavan, Prakash V; Pandit, Aniruddha B

    2014-05-01

    In the present work, degradation of reactive orange 4 dye (RO4) has been investigated using hydrodynamic cavitation (HC) and in combination with other AOP's. In the hybrid techniques, combination of hydrodynamic cavitation and other oxidizing agents such as H2O2 and ozone have been used to get the enhanced degradation efficiency through HC device. The hydrodynamic cavitation was first optimized in terms of different operating parameters such as operating inlet pressure, cavitation number and pH of the operating medium to get the maximum degradation of RO4. Following the optimization of HC parameters, the degradation of RO4 was carried out using the combination of HC with H2O2 and ozone. It has been found that the efficiency of the HC can be improved significantly by combining it with H2O2 and ozone. The mineralization rate of RO4 increases considerably with 14.67% mineralization taking place using HC alone increases to 31.90% by combining it with H2O2 and further increases to 76.25% through the combination of HC and ozone. The synergetic coefficient of greater than one for the hybrid processes of HC+H2O2 and HC+Ozone has suggested that the combination of HC with other oxidizing agents is better than the individual processes for the degradation of dye effluent containing RO4. The combination of HC with ozone proves to be the most energy efficient method for the degradation of RO4 as compared to HC alone and the hybrid process of HC and H2O2. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Removal of pharmaceuticals from wastewater by biological processes, hydrodynamic cavitation and UV treatment.

    Science.gov (United States)

    Zupanc, Mojca; Kosjek, Tina; Petkovšek, Martin; Dular, Matevž; Kompare, Boris; Širok, Brane; Blažeka, Željko; Heath, Ester

    2013-07-01

    To augment the removal of pharmaceuticals different conventional and alternative wastewater treatment processes and their combinations were investigated. We tested the efficiency of (1) two distinct laboratory scale biological processes: suspended activated sludge and attached-growth biomass, (2) a combined hydrodynamic cavitation-hydrogen peroxide process and (3) UV treatment. Five pharmaceuticals were chosen including ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac, and an active metabolite of the lipid regulating agent clofibric acid. Biological treatment efficiency was evaluated using lab-scale suspended activated sludge and moving bed biofilm flow-through reactors, which were operated under identical conditions in respect to hydraulic retention time, working volume, concentration of added pharmaceuticals and synthetic wastewater composition. The suspended activated sludge process showed poor and inconsistent removal of clofibric acid, carbamazepine and diclofenac, while ibuprofen, naproxen and ketoprofen yielded over 74% removal. Moving bed biofilm reactors were filled with two different types of carriers i.e. Kaldnes K1 and Mutag BioChip™ and resulted in higher removal efficiencies for ibuprofen and diclofenac. Augmentation and consistency in the removal of diclofenac were observed in reactors using Mutag BioChip™ carriers (85%±10%) compared to reactors using Kaldnes carriers and suspended activated sludge (74%±22% and 48%±19%, respectively). To enhance the removal of pharmaceuticals hydrodynamic cavitation with hydrogen peroxide process was evaluated and optimal conditions for removal were established regarding the duration of cavitation, amount of added hydrogen peroxide and initial pressure, all of which influence the efficiency of the process. Optimal parameters resulted in removal efficiencies between 3-70%. Coupling the attached-growth biomass biological treatment, hydrodynamic cavitation/hydrogen peroxide process and UV treatment

  1. Decontamination of unsymmetrical dimethylhydrazine waste water by hydrodynamic cavitation-induced advanced Fenton process.

    Science.gov (United States)

    Torabi Angaji, Mahmood; Ghiaee, Reza

    2015-03-01

    A pilot scale hydrodynamic cavitation (HC) reactor, using iron metal blades, as the heterogeneous catalyst, with no external source of H₂O₂ was developed for catalytic decontamination of unsymmetrical dimethylhydrazine (UDMH) waste water. 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 effects of the applied catalyst, pH of the initial solution (1.0-9.7), initial UDMH concentration (2-15 mg/l), inlet pressure (5.5-7.8bar), and downstream pressure (2-6 bar), have been investigated. The results showed that the highest cavitation yield can be obtained at pH 3 and initial UDMH concentration of 10mg/l. Also, an increase in the inlet pressure would lead to an increase in the extent of UDMH degradation. In addition, the optimum value of 3 bar was determined for the downstream pressure that resulted to 98.6% degradation of UDMH after 120 min of processing time. Neither n-nitrosodimethylamine (NDMA) nor any other toxic byproduct (/end-product) was observed in the investigated samples. Formic acid and acetic acid, as well as nitromethane, were identified as oxidation by-products. The present work has conclusively established that hydrodynamic cavitation in combination with Fenton's chemistry can be effectively used for the degradation of UDMH. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. 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)

  3. Hydrodynamic cavitation to prevent legionella and scaling; Hydrodynamische cavitatie voorkomt legionella en kalk

    Energy Technology Data Exchange (ETDEWEB)

    Van Baarle, D. (ed.)

    2006-03-15

    To prevent biofouling, legionella, scaling and corrosion in heat exchangers or cooling systems chemicals are added to the process and the cooling water. An alternative is the use of so-called hydrodynamic cavitation. [Dutch] Om biofouling, kalkaanslag en corrosie tegen te gaan, worden chemicalien aan proces en koelwater toegevoegd. Er is nu ook een chemicalienvrij mechanisch alternatief om legionellavorming, corrosie en kalkafzet tegen te gaan: hydrodynamische cavitatie. Door water in een vortex-stroom te leiden ontstaan er cavitatiekrachten die (legionella)bacterieen doden en CaCO{sub 3} omvormen tot filtreerbare colloiden. Doordat het in het water aanwezige kalk niet neerslaat, verbeter de prestatie van de warmtewisselaars.

  4. 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.

  5. Eutrophic water purification efficiency using a combination of hydrodynamic cavitation and ozonation on a pilot scale.

    Science.gov (United States)

    Li, Wei-Xin; Tang, Chuan-Dong; Wu, Zhi-Lin; Wang, Wei-Min; Zhang, Yu-Feng; Zhao, Yi; Cravotto, Giancarlo

    2015-04-01

    This paper presents the purification of eutrophic water using a combination of hydrodynamic cavitation (HC) and ozonation (O3) at a continuous flow of 0.8 m(3) h(-1) on a pilot scale. The maximum removal rate of chlorophyll a using O3 alone and the HC/O3 combination was 62.3 and 78.8%, respectively, under optimal conditions, where the ozone utilization efficiency was 64.5 and 94.8% and total energy consumption was 8.89 and 8.25 kWh m(-3), respectively. Thus, the removal rate of chlorophyll a and the ozone utilization efficiency were improved by 26.5% and 46.9%, respectively, by using the combined technique. Meanwhile, total energy consumption was reduced by 7.2%. Turbidity linearly decreased with chlorophyll a removal rate, but no linear relationship exists between the removal of COD or UV254 and chlorophyll a. As expected, the suction-cavitation-assisted O3 exhibited higher energy efficiency than the extrusion-cavitation-assisted O3 and O3 alone methods.

  6. 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.

  7. Influence of hydrodynamic cavitation on the rheological properties and microstructure of formulated Greek-style yogurts.

    Science.gov (United States)

    Meletharayil, G H; Metzger, L E; Patel, Hasmukh A

    2016-11-01

    With limited applications of acid whey generated during the manufacture of Greek yogurts, an alternate processing technology to sidestep the dewheying process was developed. Milk protein concentrate (MPC) and carbon dioxide-treated milk protein concentrate (TMPC) were used as sources of protein to fortify skim milk to 9% (wt/wt) protein for the manufacture of Greek-style yogurts (GSY). The GSY bases were inoculated and fermented with frozen direct vat set yogurt culture to a pH of 4.6. Owing to the difference in buffering of MPC and TMPC, GSY with TMPC and MPC exhibited different acidification kinetics, with GSY containing TMPC having a lower fermentation time. The GSY with TMPC had a titratable acidity of 1.45% lactic acid and was comparable to acidity of commercial Greek yogurt (CGY). Hydrodynamic cavitation at 4 different rotor speeds (0, 15, 30, and 60 Hz) as a postfermentation tool reduced the consistency coefficient (K) of GSY containing TMPC from 79.4 Pa·s n at 0 Hz to 17.59 Pa·s n at 60 Hz. Similarly for GSY containing MPC, K values decreased from 165.74 Pa·s n at 0 Hz to 53.04 Pa·s n at 60 Hz. The apparent viscosity (η 100 ) was 0.25 Pa·s for GSY containing TMPC and 0.66 Pa·s for GSY containing MPC at 60 Hz. The CGY had a η 100 value of 0.74 Pa·s. Small amplitude rheological analysis performed on GSY indicated a loss of elastic modulus dependency on frequency caused by the breakdown of protein interactions with increasing cavitator rotor speeds. A steady decrease in hardness and adhesiveness values of GSY was observed with increasing cavitational intensities. Numbers of grains with a perimeter of >1mm of cavitated GSY with TMPC and MPC were 35 and 13 grains/g of yogurt, respectively, and were lower than 293 grains/g observed in CGY. The water-holding capacity of GSY was higher than that observed for a commercial strained Greek yogurt. The ability to scale up the process of hydrodynamic cavitation industrially, and the ease of controlling events of

  8. A novel rotation generator of hydrodynamic cavitation for waste-activated sludge disintegration.

    Science.gov (United States)

    Petkovšek, Martin; Mlakar, Matej; Levstek, Marjetka; Stražar, Marjeta; Širok, Brane; Dular, Matevž

    2015-09-01

    The disintegration of raw sludge is very important for enhancement of the biogas production in anaerobic digestion process as it provides easily degradable substrate for microorganisms to perform maximum sludge treatment efficiency and stable digestion of sludge at lower costs. In the present study the disintegration was studied by using a novel rotation generator of hydrodynamic cavitation (RGHC). At the first stage the analysis of hydrodynamics of the RGHC were made with tap water, where the cavitation extent and aggressiveness was evaluated. At the second stage RGHC was used as a tool for pretreatment of a waste-activated sludge (WAS), collected from wastewater treatment plant (WWTP). In case of WAS the disintegration rate was measured, where the soluble chemical oxygen demand (SCOD) and soluble Kjeldahl nitrogen were monitored and microbiological pictures were taken. The SCOD increased from initial 45 mg/L up to 602 mg/L and 12.7% more biogas has been produced by 20 passes through RGHC. The results were obtained on a pilot bioreactor plant, volume of 400 L. Copyright © 2015. Published by Elsevier B.V.

  9. Effective method of treatment of effluents from production of bitumens under basic pH conditions using hydrodynamic cavitation aided by external oxidants.

    Science.gov (United States)

    Boczkaj, Grzegorz; Gągol, Michał; Klein, Marek; Przyjazny, Andrzej

    2018-01-01

    Utilization of cavitation in advanced oxidation processes (AOPs) is a promising trend in research on treatment of industrial effluents. The paper presents the results of investigations on the use of hydrodynamic cavitation aided by additional oxidation processes (O 3 /H 2 O 2 /Peroxone) to reduce the total pollution load in the effluent from the production of bitumens. A detailed analysis of changes in content of volatile organic compounds (VOCs) for all processes studied was also performed. The studies revealed that the most effective treatment process involves hydrodynamic cavitation aided by ozonation (40% COD reduction and 50% BOD reduction). The other processes investigated (hydrodynamic cavitation+H 2 O 2 , hydrodynamic cavitation+Peroxone and hydrodynamic cavitation alone) ensure reduction of COD by 20, 25 and 13% and reduction of BOD by 49, 32 and 18%, respectively. The results of this research revealed that most of the VOCs studied are effectively degraded. The formation of byproducts is one of the aspects that must be considered in evaluation of the AOPs studied. This work confirmed that furfural is one of the byproducts whose concentration increased during treatment by hydrodynamic cavitation alone as well as hydrodynamic cavitation aided by H 2 O 2 as an external oxidant and it should be controlled during treatment processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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.

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

    Science.gov (United States)

    Zhou, Yufeng; Gao, Xiaobin Wilson

    2016-09-21

    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.

  12. Degradation of reactive blue 13 using hydrodynamic cavitation: Effect of geometrical parameters and different oxidizing additives.

    Science.gov (United States)

    Rajoriya, Sunil; Bargole, Swapnil; Saharan, Virendra Kumar

    2017-07-01

    Decolorization of reactive blue 13 (RB13), a sulphonated azo dye, was investigated using hydrodynamic cavitation (HC). The aim of research article is to check the influence of geometrical parameters (total flow area, the ratio of throat perimeter to its cross-sectional area, throat shape and size, etc.) and configuration of the cavitating devices on decolorization of RB13 in aqueous solution. For this purpose, eight cavitating devices i.e. Circular and slit venturi, and six orifice plates having different flow area and perimeter were used in the present work. Initially, the effects of various operating parameters such as solution pH, initial dye concentration, operating inlet pressure and cavitation number on the decolorization of RB13 have been investigated, and the optimum operating conditions were found. Kinetic analysis revealed that the decolorization and mineralization of RB13 using HC followed first order reaction kinetics. Almost 47% decolorization of RB13 was achieved using only HC with slit venturi as a cavitating device at an optimum inlet pressure of 0.4MPa and pH of the solution as 2.0. It has been found that in case of orifice plates, higher decolorization rate of 4×10 -3 min -1 was achieved using orifice plate 2 (OP2) which is having higher flow area and perimeter (α=2.28). The effect of process intensifying agents (hydrogen peroxide and ferrous sulphate) and different gaseous additives (oxygen and ozone) on the extent of decolorization of RB13 were also examined. Almost 66% decolorization of RB13 was achieved using HC combined with 2Lmin -1 of oxygen and in combination with ferrous sulphate (1:3). Nearly 91% decolorization was achieved using HC combined with H 2 O 2 at an optimum molar ratio (dye:H 2 O 2 ) of 1:20 while almost complete decolorization was observed in 15min using a combination of HC and ozone at 3gh -1 ozone feed rate. Maximum 72% TOC was removed using HC coupled with 3gh -1 ozone feed rate. Copyright © 2017 Elsevier B.V. All

  13. Hydrodynamic cavitation as a novel pretreatment approach for bioethanol production from reed.

    Science.gov (United States)

    Kim, Ilgook; Lee, Ilgyu; Jeon, Seok Hwan; Hwang, Taewoon; Han, Jong-In

    2015-09-01

    In this study, hydrodynamic cavitation (HC) was employed as a physical means to improve alkaline pretreatment of reed. The HC-assisted alkaline pretreatment was undertaken to evaluate the influence of NaOH concentration (1-5%), solid-to-liquid ratio (5-15%), and reaction time (20-60 min) on glucose yield. The optimal condition was found to be 3.0% NaOH at solid-to-liquid (S/L) ratio of 11.8% for 41.1 min, which resulted in the maximum glucose yield of 326.5 g/kg biomass. Furthermore, simultaneous saccharification and fermentation (SSF) was conducted to assess the ethanol production. An ethanol concentration of 25.9 g/L and ethanol yield of 90% were achieved using batch SSF. These results clearly demonstrated HC system can be indeed a promising pretreatment tool for lignocellulosic bioethanol production. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Hydrodynamic cavitation-assisted alkaline pretreatment as a new approach for sugarcane bagasse biorefineries.

    Science.gov (United States)

    Terán Hilares, Ruly; Dos Santos, Júlio César; Ahmed, Muhammad Ajaz; Jeon, Seok Hwan; da Silva, Silvio Silvério; Han, Jong-In

    2016-08-01

    Hydrodynamic cavitation (HC) was employed in order to improve the efficiency of alkaline pretreatment of sugarcane bagasse (SCB). Response surface methodology (RSM) was used to optimize pretreatment parameters: NaOH concentration (0.1-0.5M), solid/liquid ratio (S/L, 3-10%) and HC time (15-45min), in terms of glucan content, lignin removal and enzymatic digestibility. Under an optimal HC condition (0.48M of NaOH, 4.27% of S/L ratio and 44.48min), 52.1% of glucan content, 60.4% of lignin removal and 97.2% of enzymatic digestibility were achieved. Moreover, enzymatic hydrolysis of the pretreated SCB resulted in a yield 82% and 30% higher than the untreated and alkaline-treated controls, respectively. HC was found to be a potent and promising approach to pretreat lignocellulosic biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Pilot scale intensification of rubber seed (Hevea brasiliensis) oil via chemical interesterification using hydrodynamic cavitation technology.

    Science.gov (United States)

    Bokhari, Awais; Yusup, Suzana; Chuah, Lai Fatt; Klemeš, Jiří Jaromír; Asif, Saira; Ali, Basit; Akbar, Majid Majeed; Kamil, Ruzaimah Nik M

    2017-10-01

    Chemical interesterification of rubber seed oil has been investigated for four different designed orifice devices in a pilot scale hydrodynamic cavitation (HC) system. Upstream pressure within 1-3.5bar induced cavities to intensify the process. An optimal orifice plate geometry was considered as plate with 1mm dia hole having 21 holes at 3bar inlet pressure. The optimisation results of interesterification were revealed by response surface methodology; methyl acetate to oil molar ratio of 14:1, catalyst amount of 0.75wt.% and reaction time of 20min at 50°C. HC is compared to mechanical stirring (MS) at optimised values. The reaction rate constant and the frequency factor of HC were 3.4-fold shorter and 3.2-fold higher than MS. The interesterified product was characterised by following EN 14214 and ASTM D 6751 international standards. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Anaerobic Digestion of Cattle Manure Influenced by Swirling Jet Induced Hydrodynamic Cavitation.

    Science.gov (United States)

    Langone, Michela; Soldano, Mariangela; Fabbri, Claudio; Pirozzi, Francesco; Andreottola, Gianni

    2018-04-01

    In this work, a modified swirling jet-induced cavitation has been employed for increasing anaerobic digestion efficiency of cattle manure. The hydrodynamic cavitation (HC) treatment improved the organic matter solubilization and the anaerobic biodegradability of cattle manure. The degree of disintegration increased by 5.8, 8.9, and 15.8% after the HC treatment at 6.0, 7.0, and 8.0 bars, respectively. However, the HC treatment at 7.0 bars had better results in terms of methane production. This result may be attributed to the possible formation of toxic and refractory compounds at higher inlet pressures, which could inhibit the methanization process. Further, total Kjeldahl nitrogen content was found to decrease with increasing inlet pressures, as the pH and the turbulent mixing favored the ammonia stripping processes. HC treatment decreased the viscosity of the treated cattle manure, favoring the manure pumping and mixing. Considerations on the energy input due to the HC pre-treatment and the energy output due to the enhanced methane yield have been presented. A positive energy balance can be obtained looking at the improved operational practices in the anaerobic digesters after the implementation of the HC pre-treatment.

  17. Hydrodynamic cavitation as a strategy to enhance the efficiency of lignocellulosic biomass pretreatment.

    Science.gov (United States)

    Terán Hilares, Ruly; Ramos, Lucas; da Silva, Silvio Silvério; Dragone, Giuliano; Mussatto, Solange I; Santos, Júlio César Dos

    2018-06-01

    Hydrodynamic cavitation (HC) is a process technology with potential for application in different areas including environmental, food processing, and biofuels production. Although HC is an undesirable phenomenon for hydraulic equipment, the net energy released during this process is enough to accelerate certain chemical reactions. The application of cavitation energy to enhance the efficiency of lignocellulosic biomass pretreatment is an interesting strategy proposed for integration in biorefineries for the production of bio-based products. Moreover, the use of an HC-assisted process was demonstrated as an attractive alternative when compared to other conventional pretreatment technologies. This is not only due to high pretreatment efficiency resulting in high enzymatic digestibility of carbohydrate fraction, but also, by its high energy efficiency, simple configuration, and construction of systems, besides the possibility of using on the large scale. This paper gives an overview regarding HC technology and its potential for application on the pretreatment of lignocellulosic biomass. The parameters affecting this process and the perspectives for future developments in this area are also presented and discussed.

  18. Hydrodynamic cavitation as an efficient pretreatment method for lignocellulosic biomass: A parametric study.

    Science.gov (United States)

    Terán Hilares, Ruly; de Almeida, Gabriela Faria; Ahmed, Muhammad Ajaz; Antunes, Felipe A F; da Silva, Silvio Silvério; Han, Jong-In; Santos, Júlio César Dos

    2017-07-01

    Hydrodynamic cavitation (HC), which is a highly destructive force, was employed for pretreatment of sugarcane bagasse (SCB). The efficacy of HC was studied using response surface methodology (RSM) with determining parameters varied: inlet pressure of 1-3bar, temperature of 40-70°C, and alkaline concentration of 0.1-0.3M. At the best condition (3bar, 70°C and 0.3M NaOH), 93.05% and 94.45% of hydrolysis yield of cellulose and hemicellulose, respectively, were obtained within 30min of pretreatment time. Also, pretreatment time higher than 10min had little to do regarding to SCB composition changes using different orifice plates (16 and 27 holes, with corresponding cavitation number of 0.017 and 0.048, respectively), with higher hydrolysis yield observed at 20min of process. Therefore, HC-based approach could lead to a high yield of hydrolysis, as long as a treatment condition was right; it could be so at mild conditions and at short running time. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Energy Efficiency for Biodiesel Production by Combining Two Orifices in Hydrodynamic Cavitation Reactor

    Directory of Open Access Journals (Sweden)

    Mahlinda Mahlinda

    2014-12-01

    Full Text Available Research of energy efficiency for biodiesel production process by combining two orifices on  hydrodynamic cavitation reactor had been carried out. The aim of this reseach was to studied effect of the number of orifices toward increasing temperature without using external energy source to produce biodiesel that generated by cavitation effects on orifices. The results of preliminary research showed by combining two orifices arranged in series can produce the highest thermal energy reached 48oC. Result of biodiesel production showed that yield of the highest biodiesel was 96.34% using molar ratio a methanol:oil with comparison 6:1, KOH as catalyst (1% for 50 minutes processing time. For biodiesel quality testing showed all selected parameter met the requirements of the Indonesian National Standard (SNI 04-7182:2006. Identification of biodiesel compound using GCMS showed the biodiesel compounds consisted of methyl oleate, methyl palmitate, acid linoleid, methyl stearate, palmitic acid and oleic acid with the total contents 98.39%.

  20. Synergetic effect of combination of AOP's (hydrodynamic cavitation and H₂O₂) on the degradation of neonicotinoid class of insecticide.

    Science.gov (United States)

    Raut-Jadhav, Sunita; Saharan, Virendra Kumar; Pinjari, Dipak; Sonawane, Shirish; Saini, Daulat; Pandit, Aniruddha

    2013-10-15

    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 H2O2. 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 H2O2 process on the rate of degradation of imidacloprid. Significant enhancement in the rate of degradation of imidacloprid has been observed using HC+H2O2 process which lead to a complete degradation of imidacloprid in 45 min of operation using optimal molar ratio of imidacloprid:H2O2 as 1:40. Substantial synergetic effect has been observed using HC+H2O2 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 H2O2 can be effectively used for degradation of imidacloprid. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Effect of process intensifying parameters on the hydrodynamic cavitation based degradation of commercial pesticide (methomyl) in the aqueous solution.

    Science.gov (United States)

    Raut-Jadhav, Sunita; Saini, Daulat; Sonawane, Shirish; Pandit, Aniruddha

    2016-01-01

    Methomyl, a carbamate pesticide, is classified as a pesticide of category-1 toxicity and hence shows harmful effects on both human and aquatic life. In the present work, the degradation of methomyl has been studied by using hydrodynamic cavitation reactor (HC) and its combination with intensifying agents such as H2O2, fenton reagent and ozone (hybrid processes). Initially, the optimization of operating parameters such pH and inlet pressure to the cavitating device (circular venturi) has been carried out for maximizing the efficacy of hydrodynamic cavitation. Further degradation study of methomyl by the application of hybrid processes was carried out at an optimal pH of 2.5 and the optimal inlet pressure of 5 bar. Significant synergetic effect has been observed in case of all the hybrid processes studied. Synergetic coefficient of 5.8, 13.41 and 47.6 has been obtained by combining hydrodynamic cavitation with H2O2, fenton process and ozone respectively. Efficacy of individual and hybrid processes has also been obtained in terms of energy efficiency and extent of mineralization. HC+Ozone process has proved to be the most effective process having highest synergetic coefficient, energy efficiency and the extent of mineralization. The study has also encompassed the identification of intermediate by-products generated during the degradation and has proposed the probable degradation pathway. It has been conclusively established that hydrodynamic cavitation in the presence of intensifying agents can effectively be used for complete degradation of methomyl. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Degradation of carbamazepine using hydrodynamic cavitation combined with advanced oxidation processes.

    Science.gov (United States)

    Thanekar, Pooja; Panda, Mihir; Gogate, Parag R

    2018-01-01

    Degradation of carbamazepine (CBZ), a widely detected recalcitrant pharmaceutical in sewage treatment plant (STP) effluent, has been studied in the present work using combination of hydrodynamic cavitation (HC) and advanced oxidation processes (AOPs). Due to its recalcitrant nature, it cannot be removed effectively by the conventional wastewater treatment plants (WWTPs) which make CBZ a pharmaceutical of very high environmental relevance and impact as well as stressing the need for developing new treatment schemes. In the present study, the effect of inlet pressure (3-5bar) and operating pH (3-11) on the extent of degradation have been initially studied with an objective of maximizing the degradation using HC alone. The established optimum conditions as pressure of 4bar and pH of 4 resulted in maximum degradation of CBZ as 38.7%. The combined approaches of HC with ultraviolet irradiation (HC+UV), hydrogen peroxide (HC+H 2 O 2 ), ozone (HC+O 3 ) as well as combination of HC, H 2 O 2 and O 3 (HC+H 2 O 2 +O 3 ) have been investigated under optimized pressure and operating pH. It was observed that a significant increase in the extent of degradation is obtained for the combined operations of HC+H 2 O 2 +O 3 , HC+O 3 , HC+H 2 O 2 , and HC+UV with the actual extent of degradation being 100%, 91.4%, 58.3% and 52.9% respectively. Kinetic analysis revealed that degradation of CBZ fitted into first order kinetics model for all the approaches. The processes were also compared on the basis of cavitational yield and also in terms of total treatment cost. Overall, it has been demonstrated that combined process of HC, H 2 O 2 and O 3 can be effectively used for treatment of wastewater containing CBZ. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Hydrodynamic cavitation: characterization of a novel design with energy considerations for the inactivation of Saccharomyces cerevisiae in apple juice.

    Science.gov (United States)

    Milly, P J; Toledo, R T; Kerr, W L; Armstead, D

    2008-08-01

    A Shockwave Power Reactor consisting of an annulus with a rotating pock-marked inner cylinder was used to induce hydrodynamic cavitation in calcium-fortified apple juice flowing in the annular space. Lethality on Saccharomyces cerevisiae was assessed at processing temperatures of 65 and 76.7 degrees C. Details of the novel equipment design were presented and energy consumption was compared to conventional and pulsed electric fields processing technologies. The mean log cycle reduction of S. cerevisiae was 6.27 CFU/mL and all treatments resulted in nonrecoverable viable cells. Induced lethality from hydrodynamic cavitation on S. cerevisiae exceeded the predicted values based on experimentally determined thermal resistance. Rotation of 3000 and 3600 rpm at flow rates greater than 1.0 L/min raised product temperature from 20 to 65.6 or 76.7 degrees C, respectively, and energy input was less than 220 kJ/kg. Conversion efficiency from electrical to thermal was 55% to 84%. Hydrodynamic cavitation enhanced lethality of spoilage microorganisms in minimally processed juices and reduced energy usage.

  6. Leadership set-up

    DEFF Research Database (Denmark)

    Thude, Bettina Ravnborg; Stenager, Egon; von Plessen, Christian

    2018-01-01

    . Findings: The study found that the leadership set-up did not have any clear influence on interdisciplinary cooperation, as all wards had a high degree of interdisciplinary cooperation independent of which leadership set-up they had. Instead, the authors found a relation between leadership set-up and leader...... could influence legitimacy. Originality/value: The study shows that leadership set-up is not the predominant factor that creates interdisciplinary cooperation; but rather, leader legitimacy also should be considered. Additionally, the study shows that leader legitimacy can be difficult to establish...... and that it cannot be taken for granted. This is something chief executive officers should bear in mind when they plan and implement new leadership structures. Therefore, it would also be useful to look more closely at how to achieve legitimacy in cases where the leader is from a different profession to the staff....

  7. The effects of waste-activated sludge pretreatment using hydrodynamic cavitation for methane production.

    Science.gov (United States)

    Lee, Ilgyu; Han, Jong-In

    2013-11-01

    Disintegration of waste-activated sludge (WAS) is regarded as a prerequisite of the anaerobic digestion (AD) process to reduce sludge volume and increase methane yield. Hydrodynamic cavitation (HC), which shares a similar underlying principle with ultrasonication but is energy-efficient, was employed as a physical means to break up WAS. Compared with ultrasonic (180-3600 kJ/kg TS) and thermal methods (72,000 kJ/kg TS), HC (60-1200 kJ/kg TS) found to consume significantly low power. A synergetic effect was observed when HC was combined with alkaline treatment in which NaOH, KOH, and Ca(OH)2 were used as alkaline catalysts at pH ranging from 8 to 13. As expected, the production yield of CH4 gas increased proportionally as WAS disintegration proceeded. HC, when combined with alkaline pretreatment, was found to be a cost-effective substitute to conventional methods for WAS pretreatment. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Treatment of persistent organic pollutants in wastewater using hydrodynamic cavitation in synergy with advanced oxidation process.

    Science.gov (United States)

    Badmus, Kassim Olasunkanmi; Tijani, Jimoh Oladejo; Massima, Emile; Petrik, Leslie

    2018-03-01

    Persistent organic pollutants (POPs) are very tenacious wastewater contaminants. The consequences of their existence have been acknowledged for negatively affecting the ecosystem with specific impact upon endocrine disruption and hormonal diseases in humans. Their recalcitrance and circumvention of nearly all the known wastewater treatment procedures are also well documented. The reported successes of POPs treatment using various advanced technologies are not without setbacks such as low degradation efficiency, generation of toxic intermediates, massive sludge production, and high energy expenditure and operational cost. However, advanced oxidation processes (AOPs) have recently recorded successes in the treatment of POPs in wastewater. AOPs are technologies which involve the generation of OH radicals for the purpose of oxidising recalcitrant organic contaminants to their inert end products. This review provides information on the existence of POPs and their effects on humans. Besides, the merits and demerits of various advanced treatment technologies as well as the synergistic efficiency of combined AOPs in the treatment of wastewater containing POPs was reported. A concise review of recently published studies on successful treatment of POPs in wastewater using hydrodynamic cavitation technology in combination with other advanced oxidation processes is presented with the highlight of direction for future research focus.

  9. 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). Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Degradation of ibuprofen by hydrodynamic cavitation: Reaction pathways and effect of operational parameters.

    Science.gov (United States)

    Musmarra, Dino; Prisciandaro, Marina; Capocelli, Mauro; Karatza, Despina; Iovino, Pasquale; Canzano, Silvana; Lancia, Amedeo

    2016-03-01

    Ibuprofen (IBP) is an anti-inflammatory drug whose residues can be found worldwide in natural water bodies resulting in harmful effects to aquatic species even at low concentrations. This paper deals with the degradation of IBP in water by hydrodynamic cavitation in a convergent-divergent nozzle. Over 60% of ibuprofen was degraded in 60 min with an electrical energy per order (EEO) of 10.77 kWh m(-3) at an initial concentration of 200 μg L(-1) and a relative inlet pressure pin=0.35 MPa. Five intermediates generated from different hydroxylation reactions were identified; the potential mechanisms of degradation were sketched and discussed. The reaction pathways recognized are in line with the relevant literature, both experimental and theoretical. By varying the pressure upstream the constriction, different degradation rates were observed. This effect was discussed according to a numerical simulation of the hydroxyl radical production identifying a clear correspondence between the maximum kinetic constant kOH and the maximum calculated OH production. Furthermore, in the investigated experimental conditions, the pH parameter was found not to affect the extent of degradation; this peculiar feature agrees with a recently published kinetic insight and has been explained in the light of the intermediates of the different reaction pathways. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Decolorization of azo dyes Orange G using hydrodynamic cavitation coupled with heterogeneous Fenton process.

    Science.gov (United States)

    Cai, Meiqiang; Su, Jie; Zhu, Yizu; Wei, Xiaoqing; Jin, Micong; Zhang, Haojie; Dong, Chunying; Wei, Zongsu

    2016-01-01

    The present work demonstrates the application of the combination of hydrodynamic cavitation (HC) and the heterogeneous Fenton process (HF, Fe(0)/H2O2) for the decolorization of azo dye Orange G (OG). The effects of main affecting operation conditions such as the inlet fluid pressure, initial concentration of OG, H2O2 and zero valent iron (ZVI), the fixed position of ZVI, and medium pH on decolorization efficiency were discussed with guidelines for selection of optimum parameters. The results revealed that the acidic conditions are preferred for OG decolorizaiton. The decolorization rate increased with increasing H2O2 and ZVI concentration and decreased with increasing OG initial concentration. Besides, the decolorization rate was strongly dependent on the fixed position of ZVI. The analysis results of degradation products using liquid chromatography-ESI-TOF mass spectrometry revealed that the degradation mechanism of OG proceeds mainly via reductive cleavage of the azo linkage due to the attack of hydroxyl radical. The present work has conclusively established that the combination of HC and HF can be more energy efficient and gives higher decolorization rate of OG as compared with HC and HF alone. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Monitoring of full-scale hydrodynamic cavitation pretreatment in agricultural biogas plant.

    Science.gov (United States)

    Garuti, Mirco; Langone, Michela; Fabbri, Claudio; Piccinini, Sergio

    2018-01-01

    The implementation of hydrodynamic cavitation (HC) pretreatment for enhancing the methane potential from agricultural biomasses was evaluated in a full scale agricultural biogas plant, with molasses and corn meal as a supplementary energy source. HC batch tests were run to investigate the influence on methane production, particle size and viscosity of specific energy input. 470kJ/kgTS was chosen for the full-scale implementation. Nearly 6-months of operational data showed that the HC pretreatment maximized the specific methane production of about 10%, allowing the biogas plant to get out of the fluctuating markets of supplementary energy sources and to reduce the methane emissions. HC influenced viscosity and particle size of digestate, contributing to reduce the energy demand for mixing, heating and pumping. In the light of the obtained results the HC process appears to be an attractive and energetically promising alternative to other pretreatments for the degradation of biomasses in biogas plant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Synergetic pretreatment of waste activated sludge by hydrodynamic cavitation combined with Fenton reaction for enhanced dewatering.

    Science.gov (United States)

    Cai, Meiqiang; Hu, Jianqiang; Lian, Guanghu; Xiao, Ruiyang; Song, Zhijun; Jin, Micong; Dong, Chunying; Wang, Quanyuan; Luo, Dewen; Wei, Zongsu

    2018-04-01

    The dewatering of waste activated sludge by integrated hydrodynamic cavitation (HC) and Fenton reaction was explored in this study. We first investigated the effects of initial pH, sludge concentration, flow rate, and H 2 O 2 concentration on the sludge dewaterability represented by water content, capillary suction time and specific resistance to filtration. The results of dewatering tests showed that acidic pH and low sludge concentration were favorable to improve dewatering performance in the HC/Fenton system, whereas optimal flow rate and H 2 O 2 concentration applied depended on the system operation. To reveal the synergism of HC/Fenton treatment, a suite of analysis were implemented: three-dimensional excitation emission matrix (3-DEEM) spectra of extracellular polymeric substances (EPS) such as proteins and polysaccharides, zeta potential and particle size of sludge flocs, and SEM/TEM imaging of sludge morphology. The characterization results indicate a three-step mechanism, namely HC fracture of different EPS in sludge flocs, Fenton oxidation of the released EPS, and Fe(III) re-flocculation, that is responsible for the synergistically enhanced sludge dewatering. Results of current study provide a basis to improve our understanding on the sludge dewatering performance by HC/Fenton treatment and possible scale-up of the technology for use in wastewater treatment plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Improving biogas production from continuous co-digestion of oily wastewater and waste-activated sludge by hydrodynamic cavitation pre-treatment.

    Science.gov (United States)

    Habashi, Nima; Alighardashi, Abolghasem; Mennerich, Artur; Mehrdadi, Nasser; Torabian, Ali

    2018-04-01

    Hydrodynamic cavitation (HC) was evaluated as a pretreatment for synthetic oily wastewater (OWW) to be co-digested with waste-activated sludge (WAS). The main objective of the present research was the enhancement of biogas production by the application of HC pretreatment. HC was applied to the OWW, and the OWW and WAS were added to a 50 L continuous digestion reactor. As a control system, an identical digestion reactor was set up for co-digestion of the WAS and the OWW without pretreatment. The reactors were initially filled with inoculum and the hydraulic retention time (HRT) was set to 22 d. The HRT was gradually reduced to 19, 16, and finally 13 d, but the substrate quality was kept constant. The loading rate, accordingly, increased from 0.86 to 1.46 g TVS/(L d). The biogas volume was recorded online and its quality was analyzed regularly. The HC improved biogas production up to 43% at 22 d of HRT. Reducing the HRT decreased biogas production from the main reactor while that of the control reactor was more or less constant. HC also increased the biogas methane content; the methane concentration of the main reactor was about 3% higher than the methane concentration of the control reactor. The main reactor experienced no clogging or accumulation of fatty materials.

  16. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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.

  18. Analysis of hydrodynamical pressure of cavitation flow on the boundary surface

    International Nuclear Information System (INIS)

    Volin, V.E.; Donchenko, E.G.; Chepajkin, G.A.; Lunatsi, E.D.; Chernishov, P.S.; Shvartser, A.L.

    1976-01-01

    This paper substantiates the necessity of receiving test data for creation of the methods of cavitation impact impulses on the hydraulic machines and hydraulic structures. The paper describes the methodics of experimental research of intensity of impact cavitation impulses on the elements of flowing canals at different regimes of operation; the method of determining the expected erosion in flowing canals; the method of measuring the parameters of cavitation impacts on the wall of flowing canals with the use of easily damaged varnished coverings, piezo-electric pressure transducers and amplitude and spectrum analysators. The form of a separate cavitation impact is established, the sequence of impact frequency is determined and the amplitude spectra of impacts are obtained. The analysis of test results is given

  19. Development of a novel electric field-assisted modified hydrodynamic cavitation system for disintegration of waste activated sludge.

    Science.gov (United States)

    Jung, Kyung-Won; Hwang, Min-Jin; Yun, Yeo-Myeong; Cha, Min-Jung; Ahn, Kyu-Hong

    2014-09-01

    In this current study, we present a modified hydrodynamic cavitation device that combines an electric field to substitute for the chemical addition. A modified HC system is basically an orifice plate and crisscross pipe assembly, in which the crisscross pipe imparts some turbulence, which creates collision events. This study shows that for maximizing disintegration, combining HC system, which called electric field-assisted modified orifice plate hydrodynamic cavitation (EFM-HC) in this study, with an electric field is important. Various HC systems were compared in terms of disintegration of WAS, and, among them, the EFM-HC system exhibited the best performance with the highest disintegration efficiency of 47.0±2.0% as well as the destruction of WAS morphological characteristics. The experimental results clearly show that a conventional HC system was successfully modified. In addition, electric field has a great potential for efficient disintegration of WAS for as a additional option in a combination treatment. This study suggests continued research in this field may lead to an appropriate design for commercial use. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Mineralisation of 2,4-dichlorophenoxyacetic acid by acoustic or hydrodynamic cavitation in conjunction with the advanced Fenton process.

    Science.gov (United States)

    Bremner, David H; Carlo, Stefano Di; Chakinala, Anand G; Cravotto, Giancarlo

    2008-04-01

    The mineralisation of 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence of zero-valent iron and hydrogen peroxide (the advanced Fenton process--AFP) whilst being subjected to acoustic or hydrodynamic cavitation is reported. If the reaction is merely stirred then there is 57% removal of TOC whilst on irradiation the figure is 64% although the latter reaction is more rapid. Use of ultrasound alone results in only 11% TOC removal in 60 min of treatment time. Addition of iron powder marginally enhances the extent of degradation but an appreciable increase is observed in the presence of hydrogen peroxide which acts as a source for hydroxyl radicals by Fenton chemistry as well as by dissociation in the presence of ultrasound. The use of hydrodynamic cavitation in conjunction with the advanced Fenton process has also been found to be a useful tool for continuous remediation of water contaminated with 2,4-D. After 20 min of treatment the residual TOC is reduced to 30% and this probably represents the remaining highly recalcitrant small organic molecules.

  1. Degradation of a cationic dye (Rhodamine 6G) using hydrodynamic cavitation coupled with other oxidative agents: Reaction mechanism and pathway.

    Science.gov (United States)

    Rajoriya, Sunil; Bargole, Swapnil; Saharan, Virendra Kumar

    2017-01-01

    In the present study, decolorization and mineralization of a cationic dye, Rhodamine 6G (Rh6G), has been carried out using hydrodynamic cavitation (HC). Two cavitating devices such as slit and circular venturi were used to generate cavitation in HC reactor. The process parameters such as initial dye concentration, solution pH, operating inlet pressure, and cavitation number were investigated in detail to evaluate their effects on the decolorization efficiency of Rh6G. Decolorization of Rh6G was marginally higher in the case of slit venturi as compared to circular venturi. The kinetic study showed that decolorization and mineralization of the dye fitted first-order kinetics. The loadings of H 2 O 2 and ozone have been optimized to intensify the decolorization and mineralization efficiency of Rh6G using HC. Nearly 54% decolorization of Rh6G was obtained using a combination of HC and H 2 O 2 at a dye to H 2 O 2 molar ratio of 1:30. The combination of HC with ozone resulted in 100% decolorization in almost 5-10min of processing time depending upon the initial dye concentration. To quantify the extent of mineralization, total organic carbon (TOC) analysis was also performed using various processes and almost 84% TOC removal was obtained using HC coupled with 3g/h of ozone. The degradation by-products formed during the complete degradation process were qualitatively identified by liquid chromatography-mass spectrometry (LC-MS) and a detailed degradation pathway has been proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Modeling the shear rate and pressure drop in a hydrodynamic cavitation reactor with experimental validation based on KI decomposition studies.

    Science.gov (United States)

    Badve, Mandar P; Alpar, Tibor; Pandit, Aniruddha B; Gogate, Parag R; Csoka, Levente

    2015-01-01

    A mathematical model describing the shear rate and pressure variation in a complex flow field created in a hydrodynamic cavitation reactor (stator and rotor assembly) has been depicted in the present study. The design of the reactor is such that the rotor is provided with surface indentations and cavitational events are expected to occur on the surface of the rotor as well as within the indentations. The flow characteristics of the fluid have been investigated on the basis of high accuracy compact difference schemes and Navier-Stokes method. The evolution of streamlining structures during rotation, pressure field and shear rate of a Newtonian fluid flow have been numerically established. The simulation results suggest that the characteristics of shear rate and pressure area are quite different based on the magnitude of the rotation velocity of the rotor. It was observed that area of the high shear zone at the indentation leading edge shrinks with an increase in the rotational speed of the rotor, although the magnitude of the shear rate increases linearly. It is therefore concluded that higher rotational speeds of the rotor, tends to stabilize the flow, which in turn results into less cavitational activity compared to that observed around 2200-2500RPM. Experiments were carried out with initial concentration of KI as 2000ppm. Maximum of 50ppm of iodine liberation was observed at 2200RPM. Experimental as well as simulation results indicate that the maximum cavitational activity can be seen when rotation speed is around 2200-2500RPM. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. 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.

  4. Synergetic effect of combination of AOP's (hydrodynamic cavitation and H2O2) on the degradation of neonicotinoid class of insecticide

    International Nuclear Information System (INIS)

    Raut-Jadhav, Sunita; Saharan, Virendra Kumar; Pinjari, Dipak; Sonawane, Shirish; Saini, Daulat; Pandit, Aniruddha

    2013-01-01

    Highlights: • Degradation of imidacloprid using hydrodynamic cavitation based techniques. • Combination of hydrodynamic cavitation and H 2 O 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 2 O 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 2 O 2 process on the rate of degradation of imidacloprid. Significant enhancement in the rate of degradation of imidacloprid has been observed using HC + H 2 O 2 process which lead to a complete degradation of imidacloprid in 45 min of operation using optimal molar ratio of imidacloprid:H 2 O 2 as 1:40. Substantial synergetic effect has been observed using HC + H 2 O 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 2 O 2 can be effectively used for degradation of imidacloprid

  5. PIV in the two phases of hydrodynamic cavitation in a venturi type section

    Science.gov (United States)

    Fuzier, Sylvie; Coudert, Sébastien; Coutier Delgosha, Olivier

    2012-11-01

    The presence of cavitation can affect the performance of turbomachinery. Attached sheet cavities on the blades induce modifications of flow dynamics and turbulence properties. This phenomenon is studied here in a configuration of 2D flow in a venturi type section. Images of the bubbles as well as of the light emitted by fluorescent particles placed in the liquid are recorded simultaneously. Velocities of the bubbles and of the liquid phase are obtained by PIV. The slip velocity is analyzed function of the number of cavitation and other physical parameters. Different levels of turbulence are correlated with different bubble structures in the dipahasic cavity.

  6. An Optical Characterization of the Effect of High-Pressure Hydrodynamic Cavitation on Diesel

    OpenAIRE

    Lockett, R. D.; Fatmi, Z.; Kuti, O.; Price, R.

    2016-01-01

    Most modern high-pressure common rail diesel fuel injection systems employ an internal pressure equalization system in order to provide the force necessary to support needle lift, enabling precise control of the injected fuel mass. This results in the return of a substantial proportion of the high-pressure diesel back to the fuel tank. The diesel fuel flow occurring in the injector spill passages is expected to be a cavitating flow, which is known to promote fuel ageing. The cavitation of die...

  7. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Background nuclei measurements and implications for cavitation inception in hydrodynamic test facilities

    Science.gov (United States)

    Venning, J. A.; Khoo, M. T.; Pearce, B. W.; Brandner, P. A.

    2018-04-01

    Water susceptibility and background nuclei content in a water tunnel are investigated using a cavitation susceptibility meter. The measured cumulative histogram of nuclei concentration against critical pressure shows a power law dependence over a large range of concentrations and pressures. These results show that the water strength is not characterised by a single tension but is susceptible to `all' tensions depending on the relevant timescale. This background nuclei population is invariant to tunnel conditions showing that it is stabilised against dissolution. Consideration of a practical cavitating flow about a sphere shows that although background nuclei may be activated, their numbers are so few compared with other sources that they are insignificant for this case.

  9. Hybrid treatment strategies for 2,4,6-trichlorophenol degradation based on combination of hydrodynamic cavitation and AOPs.

    Science.gov (United States)

    Barik, Arati J; Gogate, Parag R

    2018-01-01

    Utilization of hybrid treatment schemes involving advanced oxidation processes and hydrodynamic cavitation in the wastewater treatment forms the prime focus of the present work. The initial phase of the work includes analysis of recent literature relating to the performance of combined approach based on hydrodynamic cavitation (HC) for degradation of different pollutants followed by a detailed investigation into degradation of 2,4,6-trichlorophenol (2,4,6-TCP). The degradation of the priority pollutant, 2,4,6-TCP, using combination of HC based on slit-venturi used as the cavitating device, ozone and H 2 O 2 has been investigated. The effect of operating pressure (2-5bar) and initial pH (3-11) have been investigated for the degradation using only HC. The degradation using only ozone (100-400mg/h) and only H 2 O 2 has also been studied. The efficacy of the combined operation of HC+O 3 at different ozone flow rates (100-400mg/h) and the combined operation of HC+H 2 O 2 at different loadings of H 2 O 2 (2,4,6-TCP:H 2 O 2 as 1:1-1:7) have been subsequently investigated. The degradation efficacy has also been established for the combined treatment strategies of O 3 +H 2 O 2 and HC+O 3 +H 2 O 2 at the optimum conditions of temperature as 30°C, inlet pressure of 4bar and initial pH of 7. Extent of 2,4,6-TCP degradation, TOC and COD removal obtained for HC+O 3 process were 97.1%, 94.4% and 78.5% respectively whereas for O 3 +H 2 O 2 process, the values were 95.5%, 94.8% and 76.2% and for HC+O 3 +H 2 O 2 process the extent of reduction were 100%, 95.6% and 80.9% in the same order. The combined treatment approach as HC+O 3 +H 2 O 2 was established as the most efficient approach for complete removal of 2,4,6-TCP with near complete TOC removal. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Enhancing the aggressive intensity of hydrodynamic cavitation through a Venturi tube by increasing the pressure in the region where the bubbles collapse

    Science.gov (United States)

    Soyama, H.; Hoshino, J.

    2016-04-01

    In this paper, we used a Venturi tube for generating hydrodynamic cavitation, and in order to obtain the optimum conditions for this to be used in chemical processes, the relationship between the aggressive intensity of the cavitation and the downstream pressure where the cavitation bubbles collapse was investigated. The acoustic power and the luminescence induced by the bubbles collapsing were investigated under various cavitating conditions, and the relationships between these and the cavitation number, which depends on the upstream pressure, the downstream pressure at the throat of the tube and the vapor pressure of the test water, was found. It was shown that the optimum downstream pressure, i.e., the pressure in the region where the bubbles collapse, increased the aggressive intensity by a factor of about 100 compared to atmospheric pressure without the need to increase the input power. Although the optimum downstream pressure varied with the upstream pressure, the cavitation number giving the optimum conditions was constant for all upstream pressures.

  11. Enhancing the aggressive intensity of hydrodynamic cavitation through a Venturi tube by increasing the pressure in the region where the bubbles collapse

    Directory of Open Access Journals (Sweden)

    H. Soyama

    2016-04-01

    Full Text Available In this paper, we used a Venturi tube for generating hydrodynamic cavitation, and in order to obtain the optimum conditions for this to be used in chemical processes, the relationship between the aggressive intensity of the cavitation and the downstream pressure where the cavitation bubbles collapse was investigated. The acoustic power and the luminescence induced by the bubbles collapsing were investigated under various cavitating conditions, and the relationships between these and the cavitation number, which depends on the upstream pressure, the downstream pressure at the throat of the tube and the vapor pressure of the test water, was found. It was shown that the optimum downstream pressure, i.e., the pressure in the region where the bubbles collapse, increased the aggressive intensity by a factor of about 100 compared to atmospheric pressure without the need to increase the input power. Although the optimum downstream pressure varied with the upstream pressure, the cavitation number giving the optimum conditions was constant for all upstream pressures.

  12. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Setting up virtual private network

    International Nuclear Information System (INIS)

    Huang Hongmei; Zhang Chengjun

    2003-01-01

    Setting up virtual private network for business enterprise provides a low cost network foundation, increases enterprise's network function and enlarges its private scope. The text introduces virtual private network's principal, privileges and protocols that use in virtual private network. At last, this paper introduces several setting up virtual private network's technologies which based on LAN

  15. Setting up virtual private network

    International Nuclear Information System (INIS)

    Huang Hongmei; Zhang Chengjun

    2003-01-01

    Setting up virtual private network for business enterprise provides a low cost network foundation, increases enterprise network function and enlarges its private scope. This text introduces virtual private network principal, privileges and protocols applied in virtual private network. At last, this paper introduces several setting up virtual private network technologies which is based on LAN

  16. Performance and emission characteristics of a stationary diesel engine fuelled by Schleichera Oleosa Oil Methyl Ester (SOME produced through hydrodynamic cavitation process

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Yadav

    2018-03-01

    Full Text Available In this study, the performance and emission characteristics of biodiesel blends of 10, 20, 30 and 50% from Schleichera Oleosa oil based on hydrodynamic cavitation were compared to diesel fuel, and found to be acceptable according to the EN 14214 and ASTM D 6751 standards. The tests have been performed using a single cylinder four stroke diesel engine at different loading condition with the blended fuel at the rated speed of 1500 rpm. SOME (Schleichera Oleosa Oil Methyl Ester blended with diesel in proportions of 10%, 20%, 30% and 50% by volume and pure diesel was used as fuel. Engine performance (specific fuel consumption and brake thermal efficiency and exhaust emission (CO, CO2 and NOx were measured to evaluate the behaviour of the diesel engine running on biodiesel. The results show that the brake thermal efficiency of diesel is higher and brake specific fuel consumption is lower at all loads followed by blends of SOME and diesel. The performance parameter for B10, B20, B30 and B50 were also closer to diesel and the CO emission was found to be lesser than diesel while there was a slight increase in the CO2 and NOx. SOME produced by using hydrodynamic cavitation seems to be efficient, time saving and industrially viable. The experimental results revel that SOME-diesel blends up to 50% (v/v can be used in a diesel engine without modifications. Keywords: Performance, Emission, Diesel engine, Schleichera Oleosa Oil, Biodiesel hydrodynamic cavitation (HC

  17. An Investigation into the Effect of Hydrodynamic Cavitation on Diesel using Optical Extinction

    Science.gov (United States)

    Lockett, R. D.; Fatmi, Z.; Kuti, O.; Price, R.

    2015-12-01

    A conventional diesel and paraffinic-rich model diesel fuel were subjected to sustained cavitation in a custom-built high-pressure recirculation flow rig. Changes to the spectral extinction coefficient at 405 nm were measured using a simple optical arrangement. The spectral extinction coefficient at 405 nm for the conventional diesel sample was observed to increase to a maximum value and then asymptotically decrease to a steady-state value, while that for the paraffinic-rich model diesel was observed to progressively decrease. It is suggested that this is caused by the sonochemical pyrolysis of mono-aromatics to form primary soot-like carbonaceous particles, which then coagulate to form larger particles, which are then trapped by the filter, leading to a steady-state spectral absorbance.

  18. Hydrodynamic cavitation as a strategy to enhance the efficiency of lignocellulosic biomass pretreatment

    DEFF Research Database (Denmark)

    Terán Hilares, Ruly; Ramos, Lucas; da Silva, Silvio Silvério

    2018-01-01

    to accelerate certain chemical reactions. The application of cavitation energy to enhance the efficiency of lignocellulosic biomass pretreatment is an interesting strategy proposed for integration in biorefineries for the production of bio-based products. Moreover, the use of an HC-assisted process...... was demonstrated as an attractive alternative when compared to other conventional pretreatment technologies. This is not only due to high pretreatment efficiency resulting in high enzymatic digestibility of carbohydrate fraction, but also, by its high energy efficiency, simple configuration, and construction...... of systems, besides the possibility of using on the large scale. This paper gives an overview regarding HC technology and its potential for application on the pretreatment of lignocellulosic biomass. The parameters affecting this process and the perspectives for future developments in this area are also...

  19. A new approach for bioethanol production from sugarcane bagasse using hydrodynamic cavitation assisted-pretreatment and column reactors.

    Science.gov (United States)

    Terán Hilares, Ruly; Kamoei, Douglas Viana; Ahmed, Muhammad Ajaz; da Silva, Silvio Silvério; Han, Jong-In; Santos, Júlio César Dos

    2018-05-01

    Hydrodynamic cavitation (HC) was adopted to assist alkaline-hydrogen peroxide pretreatment of sugarcane bagasse (SCB). In the following condition: 0.29 M of NaOH, 0.78% (v/v) of H 2 O 2 , 9.95 min of process time and 3 bar of inlet pressure, 95.4% of digestibility of cellulosic fraction was achieved. To take the best use of the pretreated biomass, the overall process was intensified by way of employing a packed bed flow-through column reactor and thus enabling to handle a high solid loading of 20%, thereby leading to cellulose and hemicellulose conversions to 74.7% and 75%, respectively. In the fermentation step, a bubble column reactor was introduced to maximize ethanol production from the pretreated SCB by Scheffersomyces stipitis NRRL-Y7124, resulting in 31.50 g/L of ethanol, 0.49 g/g of ethanol yield and 0.68 g/L.h of productivity. All this showed that our HC-assisted NaOH-H 2 O 2 pretreatment strategy along with the process intensification approach might offer an option for SCB-based biorefineries. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Hydrodynamic cavitation as a novel approach for pretreatment of oily wastewater for anaerobic co-digestion with waste activated sludge.

    Science.gov (United States)

    Habashi, Nima; Mehrdadi, Nasser; Mennerich, Artur; Alighardashi, Abolghasem; Torabian, Ali

    2016-07-01

    Application of hydrodynamic cavitation (HC) was investigated with the objective of biogas production enhancement from co-digestion of oily wastewater (OWW) and waste activated sludge (WAS). Initially, the effect of HC on the OWW was evaluated in terms of energy consumption and turbidity increase. Then, several mixtures of OWW (with and without HC pretreatment) and WAS with the same concentration of total volatile solid were prepared as a substrate for co-digestion. Following, several batch co-digestion trials were conducted. To compare the biogas production, a number of digestion trials were also conducted with a mono substrate (OWW or WAS alone). The best operating condition of HC was achieved in the shortest retention time (7.5 min) with the application of 3mm diameter orifice and maximum pump rotational speed. Biogas production from all co-digestion reactors was higher than the WAS mono substrate reactors. Moreover, biogas production had a direct relationship with OWW ratio and no major inhibition was observed in any of the reactors. The biogas production was also enhanced by HC pretreatment and almost all of the reactors with HC pretreatment had higher reaction rates than the reactors without pretreatment. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Schneiderian membrane detachment using transcrestal hydrodynamic ultrasonic cavitational sinus lift: a human cadaver head study and histologic analysis.

    Science.gov (United States)

    Troedhan, Angelo; Kurrek, Andreas; Wainwright, Marcel; Jank, Siegfried

    2014-08-01

    Recent studies have suggested the osteogenic layer of the periosteum at the base of the sinus membrane to play a key role in bone regeneration after sinus lift procedures. Thus, atraumatic detachment of the sinus membrane with an intact periosteum seems mandatory. The present histologic study of fresh human cadaver heads investigated the detachment behavior and histologic integrity of the detached periosteum after application of the transcrestal hydrodynamic ultrasonic cavitational sinus lift (tHUCSL-INTRALIFT). A total of 15 sinuses in 8 fresh human cadaver heads were treated using tHUCSL-INTRALIFT. After surgery, they were checked macroscopically for damage to the sinus membrane and then processed for histologic inspection under light microscopy. A total of 150 histologic specimens, randomly selected from the core surgical sites, were investigated using hematoxylin-eosin (HE), Azan, and trichrome staining. None of the 150 inspected specimens showed any perforation or dissection of the periosteum from the subepithelial connective tissue and respiratory epithelium and were fully detached from the bony antrum floor. The connecting Sharpey fibers revealed to be cleanly separated from the sinus floor in all specimens. The results of the present study suggest tHUCSL-INTRALIFT should be used to perform predictable and safe detachment of the periosteum from the bony sinus floor as a prerequisite for undisturbed and successful physiologic subantral bone regeneration. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. 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

  4. Effects of ultrasonic and hydrodynamic cavitation on the treatment of cork wastewater by flocculation and Fenton processes.

    Science.gov (United States)

    Wu, Zhilin; Yuste-Córdoba, Francisco J; Cintas, Pedro; Wu, Zhansheng; Boffa, Luisa; Mantegna, Stefano; Cravotto, Giancarlo

    2018-01-01

    This paper reports that ultrasonic (US) and hydrodynamic cavitation (HC) are efficient strategies for the environmental remediation of cork wastewater (CW). It is necessary to remove toxic, inhibitory or refractory organic matter from CW using physical and chemical techniques (pre-treatment) prior to performing conventional biological treatment. After this biological treatment, it is also critical to further decontaminate (post-treatment) in order to meet the discharge limitation. The pre-treatment of diluted CW using Fenton oxidation (FE) alone led to COD and polyphenol (PP) removal values of 30% and 61%, respectively, while HC and US resulted in 83-90% increases in COD reduction and 26-33% increases in PP reduction. Whereas 55% and 91% COD and PP removal were achieved using flocculation (Floc) alone, COD elimination was increased by a further 7-18% under HC and US. No noticeable improvement in PP elimination was observed. US did not enhance the Floc decontamination of the original concentrated CW, however, considerable quantities of white biofilm were surprisingly generated on the CW surface after the pre-treatment, thus indicating the improvement of biodegradability of the resulting liquid. In fact, the post-treatment stage, using FE alone after having filtered the biofilms, led to reductions of 53% in COD and 90% in PP. The HC and US protocols resulted in 26-34% increases in COD elimination. HC further enhanced PP elimination caused by FE, while US resulted in lower levels of PP elimination. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Performance and emission characteristics of a stationary diesel engine fuelled by Schleichera Oleosa Oil Methyl Ester (SOME) produced through hydrodynamic cavitation process

    OpenAIRE

    Ashok Kumar Yadav; M. Emran Khan; Amit Pal; Uttam Ghosh

    2018-01-01

    In this study, the performance and emission characteristics of biodiesel blends of 10, 20, 30 and 50% from Schleichera Oleosa oil based on hydrodynamic cavitation were compared to diesel fuel, and found to be acceptable according to the EN 14214 and ASTM D 6751 standards. The tests have been performed using a single cylinder four stroke diesel engine at different loading condition with the blended fuel at the rated speed of 1500 rpm. SOME (Schleichera Oleosa Oil Methyl Ester) blended with die...

  6. Surface mechanics design by cavitation peening

    OpenAIRE

    Hitoshi Soyama

    2015-01-01

    Although impacts at cavitation bubble collapses cause severe damage in hydraulic machineries, the cavitation impacts can be utilised for surface mechanics design such as introduction of compressive residual stress and/or improvement of fatigue strength. The peening method using the cavitation impacts was called as cavitation peening. In order to reveal the peening intensity of hydrodynamic cavitation and laser cavitation, the arc height of Almen strip and duralumin plate were measured. In the...

  7. Setting up crowd science projects.

    Science.gov (United States)

    Scheliga, Kaja; Friesike, Sascha; Puschmann, Cornelius; Fecher, Benedikt

    2016-11-29

    Crowd science is scientific research that is conducted with the participation of volunteers who are not professional scientists. Thanks to the Internet and online platforms, project initiators can draw on a potentially large number of volunteers. This crowd can be involved to support data-rich or labour-intensive projects that would otherwise be unfeasible. So far, research on crowd science has mainly focused on analysing individual crowd science projects. In our research, we focus on the perspective of project initiators and explore how crowd science projects are set up. Based on multiple case study research, we discuss the objectives of crowd science projects and the strategies of their initiators for accessing volunteers. We also categorise the tasks allocated to volunteers and reflect on the issue of quality assurance as well as feedback mechanisms. With this article, we contribute to a better understanding of how crowd science projects are set up and how volunteers can contribute to science. We suggest that our findings are of practical relevance for initiators of crowd science projects, for science communication as well as for informed science policy making. © The Author(s) 2016.

  8. Hydrodynamic cavitation characteristics of an orifice system and its effects on CRUD-like SiC deposition

    International Nuclear Information System (INIS)

    Kim, Seong Man; Bang, In Cheol

    2016-01-01

    Highlights: • CRUD-like SiC deposition was prepared for examining the erosion test in the cavitation field. • We investigated the comparison between swirl flow and common flow on cavitation. • Magnitude of shock pressure was investigated at low cavitation number. - Abstract: In a nuclear power plant, chalk river unidentified deposit (CRUD) is known as a deposit that is composed of corrosion and oxidation materials. It has a porous structure, which combines with boron that is injected into the coolant for controlling power levels. The buildup of corrosion products on the fuel cladding surface has proven to be particularly significant for both BWRs and PWRs. The high temperature of the cladding surface attracts impurities and chemical additives in the reactor coolant that deposit on the fuel rod surface in a process. The deposits on a fuel rod, known as CRUD, can be tenacious, insulative compounds capable of increasing the local clad temperature and accelerating clad corrosion—sometimes to the point of fuel failure. The deposition of CRUD on fuel cladding surfaces causes uneven heating of the reactor core. The situation is exacerbated by boron, which is added to the coolant to control power levels. However, boron becomes concentrated and is deposited within thick CRUD deposits. Ultrasonic mechanisms were developed but they have limitations for decontamination. In this experiment, a decontamination test was conducted using a sample sheet that was composed of SiC/water nanofluids. In addition, it was exposed to swirl flow and common flow for checking enhanced cavitation. It is measured by a pressure film, as shock pressure is associated with cavitation number. As a pressure film is wetted easily in water, it was injected into a holder. In the experiment, the maximum shock pressure was obtained during swirl flow at a low cavitation number. This indicates that pressure was concentrated on the pressure film. Consequently, cavitation can get rid of CRUD layers

  9. Cavitation Inception Scale Effects. 1. Nuclei Distributions in Natural Waters. 2. Cavitation Inception in a Turbulent Shear Flow.

    Science.gov (United States)

    1987-05-01

    cavitation is pressure-controlled. The term hydrodynamic cavitation is some- times used to stress the dominant role of dynamic pressure in the cavitation...Diffraction Pattern of Opaque and Transparent Objects with Coherent Back- ground," Optica Acta, 11, 183-193. Peterson, F.B. (1972), " Hydrodynamic Cavitation and

  10. 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 O 3 , H 2 O 2 /O 3 , H 2 O 2 /UV and O 3 /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 O 3 and H 2 O 2 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 O 3 /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 H 2 O 2 /UV AOPs and combinations with HC. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Harness cavitation to improve processing

    Energy Technology Data Exchange (ETDEWEB)

    Pandit, A.G.; Moholkar, V.S. [Univ. of Bombay (India)

    1996-07-01

    Mention cavitation to most chemical engineers, and they undoubtedly think of it as an operational problem. Indeed, the rapid creation and then collapse of bubbles, which is after all what cavitation involves, can destroy pumps and erode other equipment. Cavitation, however, also can have a positive side--presuming it is designed for and not unplanned. In this article, the authors look at how cavitation can be harnessed to improve processes, and the mechanisms for inducing cavitation--ultrasonics and hydrodynamics--and their likely roles. Sonication, that is, the use of ultrasound, is the conventional approach for creating cavitation, and so they turn to it first. Over the past few years, a number of groups have attempted to solve the problem of scale-up and design of ultrasonic reactors. The authors review the systems that already exist and also explore a simpler and efficient alternative to the ultrasonic reactor, the hydrodynamic cavitation reactor.

  12. Acoustic cavitation studies

    Science.gov (United States)

    Crum, L. A.

    1981-09-01

    The primary thrust of this study was toward a more complete understanding of general aspects of acoustic cavitation. The effect of long-chain polymer additives on the cavitation threshold was investigated to determine if they reduced the acoustic cavitation threshold in a similar manner to the observed reduction in the cavitation index in hydrodynamic cavitation. Measurements were made of the acoustic cavitation threshold as a function of polymer concentration for additives such as guar gum and polyethelene oxide. The measurements were also made as a function of dissolved gas concentration, surface tension and viscosity. It was determined that there was a significant increase in the acoustic cavitation threshold for increased concentrations of the polymer additives (measurable effects could be obtained for concentrations as low as a few parts per million). One would normally expect that an additive that reduces surface tension to decrease the pressure required to cause a cavity to grow and thus these additives, at first thought, should reduce the threshold. However, even in the hydrodynamic case, the threshold was increased. In both of the hydrodynamic cases considered, the explanation for the increased threshold was given in terms of changed fluid dynamics rather than changed physical properties of the fluid.

  13. Cavitation simulation on marine propellers

    DEFF Research Database (Denmark)

    Shin, Keun Woo

    Cavitation on marine propellers causes thrust breakdown, noise, vibration and erosion. The increasing demand for high-efficiency propellers makes it difficult to avoid the occurrence of cavitation. Currently, practical analysis of propeller cavitation depends on cavitation tunnel test, empirical...... criteria and inviscid flow method, but a series of model test is costly and the other two methods have low accuracy. Nowadays, computational fluid dynamics by using a viscous flow solver is common for practical industrial applications in many disciplines. Cavitation models in viscous flow solvers have been...... 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...

  14. The Enhancement of H2O2/UV AOPs for the Removal of Selected Organic Pollutants from Drinking Water with Hydrodynamic Cavitation.

    Science.gov (United States)

    Čehovin, Matej; Medic, Alojz; Kompare, Boris; Žgajnar Gotvajn, Andreja

    2016-12-01

    Drinking water contains organic matter that occasionally needs to be treated to assure its sufficient quality and safety for the consumers. H2O2 and UV advanced oxidation processes (H2O2/UV AOPs) were combined with hydrodynamic cavitation (HC) to assess the effects on the removal of selected organic pollutants. Water samples containing humic acid, methylene blue dye and micropollutants (metaldehyde, diatrizoic acid, iohexol) were treated first by H2O2 (dosages from 1 to 12 mg L-1) and UV (dosages from 300 to 2800 mJ cm-2) AOPs alone and later in combination with HC, generated by nozzles and orifice plates (4, 8, 18 orifices). Using HC, the removal of humic acid was enhanced by 5-15%, methylene blue by 5-20% and metaldehyde by approx. 10%. Under favouring conditions, i.e. high UV absorbance of the matrix (more than 0.050 cm-1 at a wavelength of 254 nm) and a high pollutant to oxidants ratio, HC was found to improve the hydrodynamic conditions in the photolytic reactor, to improve the subjection of the H2O2 to the UV fluence rate distribution and to enhance the removal of the tested organic pollutants, thus showing promising potential of further research in this field.

  15. Investigation of TiO2 photocatalyst performance for decolorization in the presence of hydrodynamic cavitation as hybrid AOP.

    Science.gov (United States)

    Bethi, Bhaskar; Sonawane, S H; Rohit, G S; Holkar, C R; Pinjari, D V; Bhanvase, B A; Pandit, A B

    2016-01-01

    In this article, an acoustic cavitation engineered novel approach for the synthesis of TiO2, cerium and Fe doped TiO2 nanophotocatalysts is reported. The prepared TiO2, cerium and Fe doped TiO2 nanophotocatalysts were characterized by XRD and TEM analysis to evaluate its structure and morphology. Photo catalytic performance of undoped TiO2 catalyst was investigated for the decolorization of crystal violet dye in aqueous solution at pH of 6.5 in the presence of hydro dynamic cavitation. Effect of catalyst doping with Fe and Ce was also studied for the decolorization of crystal violet dye. The results shows that, 0.8% of Fe-doped TiO2 exhibits maximum photocatalytic activity in the decolorization study of crystal violet dye due to the presence of Fe in the TiO2 and it may acts as a fenton reagent. Kinetic studies have also been reported for the hybrid AOP (HAOP) that followed the pseudo first-order reaction kinetics. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Transient cavitation in pipelines

    NARCIS (Netherlands)

    Kranenburg, C.

    1974-01-01

    The aim of the present study is to set up a one-dimensional mathematical model, which describes the transient flow in pipelines, taking into account the influence of cavitation and free gas. The flow will be conceived of as a three-phase flow of the liquid, its vapour and non-condensible gas. The

  17. Travelling Bubble Cavitation and Resulting Noise.

    Science.gov (United States)

    1981-03-02

    pp. 22-26, 1968. 16. Il’ichev, V. I. "Statistical Model of the Onset of Hydrodynamic Cavitation Noise," Sixth All-Union Acoustic Conference...Collected Papers, Moscow, 1968. 17. Lyamshev, L. M. "On the Theory of Hydrodynamic Cavitation Noise," Soviet Physics-Acoustics, Vol. 15, pp. 494-498, 1970. 18

  18. Decolorization of Acid Orange 7 by an electric field-assisted modified orifice plate hydrodynamic cavitation system: Optimization of operational parameters.

    Science.gov (United States)

    Jung, Kyung-Won; Park, Dae-Seon; Hwang, Min-Jin; Ahn, Kyu-Hong

    2015-09-01

    In this study, the decolorization of Acid Orange 7 (AO-7) with intensified performance was obtained using hydrodynamic cavitation (HC) combined with an electric field (graphite electrodes). As a preliminary step, various HC systems were compared in terms of decolorization, and, among them, the electric field-assisted modified orifice plate HC (EFM-HC) system exhibited perfect decolorization performance within 40 min of reaction time. Interestingly, when H2O2 was injected into the EFM-HC system as an additional oxidant, the reactor performance gradually decreased as the dosing ratio increased; thus, the remaining experiments were performed without H2O2. Subsequently, an optimization process was conducted using response surface methodology with a Box-Behnken design. The inlet pressure, initial pH, applied voltage, and reaction time were chosen as operational key factors, while decolorization was selected as the response variable. The overall performance revealed that the selected parameters were either slightly interdependent, or had significant interactive effects on the decolorization. In the verification test, complete decolorization was observed under statistically optimized conditions. This study suggests that EFM-HC is a useful method for pretreatment of dye wastewater with positive economic and commercial benefits. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Ethanol production in a simultaneous saccharification and fermentation process with interconnected reactors employing hydrodynamic cavitation-pretreated sugarcane bagasse as raw material.

    Science.gov (United States)

    Terán Hilares, Ruly; Ienny, João Vitor; Marcelino, Paulo Franco; Ahmed, Muhammad Ajaz; Antunes, Felipe A F; da Silva, Silvio Silvério; Santos, Júlio César Dos

    2017-11-01

    In this study, sugarcane bagasse (SCB) pretreated with alkali assisted hydrodynamic cavitation (HC) was investigated for simultaneous saccharification and fermentation (SSF) process for bioethanol production in interconnected column reactors using immobilized Scheffersomyces stipitis NRRL-Y7124. Initially, HC was employed for the evaluation of the reagent used in alkaline pretreatment. Alkalis (NaOH, KOH, Na 2 CO 3 , Ca(OH) 2 ) and NaOH recycled black liquor (successive batches) were used and their pretreatment effectiveness was assessed considering the solid composition and its enzymatic digestibility. In SSF process using NaOH-HC pretreatment SCB, 62.33% of total carbohydrate fractions were hydrolyzed and 17.26g/L of ethanol production (0.48g of ethanol/g of glucose and xylose consumed) was achieved. This proposed scheme of HC-assisted NaOH pretreatment together with our interconnected column reactors showed to be an interesting new approach for biorefineries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Set-up for differential manometers testing

    International Nuclear Information System (INIS)

    Ratushnyj, M.I.; Galkin, Yu.V.; Nechaj, A.G.

    1985-01-01

    Set-up characteristic for controlling and testing metrological characteristics of TPP and NPP differential manometers with extreme pressure drop upto 250 kPa is briefly described. The set-up provides with automatic and manual assignment of values of gauge air pressure with errors of 0.1 and 0.25% correspondingly. The set-up is supplied with standard equipment to measure output signals. Set-up supply is carried out by a one-phase alternating current circuit with 220 V. Air supply is carried out by O.4-0.6 MPa. pressure of a pneumatic system. Application of the set-up increases operating efficiency 5 times while checking and turning differential manometers

  1. 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.

  2. Galvanic cells: setting up the Daniell cell.

    OpenAIRE

    Milla González, Miguel

    2008-01-01

    With the reagents (0.05M copper nitrate solution, 0.05M zinc nitrate solution) and material (glassware, potentiometer, electric wire) availabe in the laboratory, the user must set up the Daniell cell. Different configurations can be possible if the half cells are filled with either electrolyte solution. The cell connections to the measuring device can also be changed. In all instances, an explanation of the set up cell is obtained as well as of the measured potential difference.

  3. Surface mechanics design by cavitation peening

    Directory of Open Access Journals (Sweden)

    Hitoshi Soyama

    2015-07-01

    Full Text Available Although impacts at cavitation bubble collapses cause severe damage in hydraulic machineries, the cavitation impacts can be utilised for surface mechanics design such as introduction of compressive residual stress and/or improvement of fatigue strength. The peening method using the cavitation impacts was called as cavitation peening. In order to reveal the peening intensity of hydrodynamic cavitation and laser cavitation, the arc height of Almen strip and duralumin plate were measured. In the case of hydrodynamic cavitation, cavitation was generated by injecting a high speed water jet into water with a pressurised chamber and an open chamber, and the cavitating jet in air was also examined. The laser cavitation was produced by a pulse laser, and a high speed observation using a high speed video camera was carried out to clarify laser abrasion and laser cavitation with detecting noise by a hydrophone. It was concluded that the peening intensity by using the cavitating jet in water with the pressurized chamber was most aggressive, and the impact induced by the laser cavitation was larger than that of the laser abrasion at the present condition.

  4. Observations of the Dynamics and Acoustics of Travelling Bubble Cavitation

    Science.gov (United States)

    1990-06-25

    Bubbles 6.1 Introduction The detailed relationship between the collapse mechanism of hydrodynamic cavitation bubbles and the resulting noise generation is...Contribution to 11th International Towing Tank Conference. Il’ichev, V. I. 1968. Statistical Model of the Onset of Hydrodynamic Cavitation Noise. Soviet...On the Theory of Hydrodynamic Cavitation Noise. Soviet Physics-Acoustics, Vol. 15, pp. 494-498. Marboe, M. L., Billet, M. L. and Thompson, D. E. 1986

  5. 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...

  6. Cavitations synthesis of carbon nanostructures

    International Nuclear Information System (INIS)

    Voropaev, S

    2011-01-01

    Originally an idea of diamonds production by hydrodynamical cavitation was presented by academician E.M. Galimov. He supposed the possibility of nature diamonds formation at fast magma flowing in kimberlitic pipes during bubbles collapse. This hypothesis assumes a number of processes, which were not under consideration until now. It concerns cavitation under high pressure, growth and stability of the gas- and vapors bubbles, their evolution, and corresponding physical- and chemical processes inside. Experimental setup to reproduce the high pressure and temperature reaction centers by means of the cavitation following the above idea was created. A few crystalline nanocarbon forms were successfully recovered after treatment of benzene (C 6 H 6 ).

  7. Hydrodynamic cavitation for water treatment

    OpenAIRE

    Gomes, Mário da Silva

    2015-01-01

    Dissertação de Mestrado Integrado em Engenharia Mecânica apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra O presente trabalho está enquadrado no estudo do fenómeno de cavitação, centrando-se essencialmente na cavitação hidrodinâmica aplicada ao tratamento de águas. Atualmente, o método de tratamento mais utilizado para a desinfeção de águas contaminadas com microrganismos é a cloração. No entanto, a utilização em excesso de cloro, associado a alguns compostos org...

  8. How to set up a psychodermatology clinic.

    Science.gov (United States)

    Aguilar-Duran, S; Ahmed, A; Taylor, R; Bewley, A

    2014-07-01

    Psychodermatology is a recognized subspecialty, but lack of awareness among dermatologists and limitation of resources make the management of these patients challenging. Clinicians are often unsure about the practicalities of setting up a psychodermatology service. There is confusion about which model is best suited to which service, and about the development of a psychodermatology multidisciplinary team. To identify the necessary steps in setting up a psychodermatology clinic. The study was based on the experience of a UK-based psychodermatology unit and the recently published standards by the UK Psychodermatology Working Party. The type of service provision will depend on the type of patients seen in the unit. The core team will be composed of a psychodermatologist and a psychologist. Access to a psychiatrist is essential if patients present with primary psychiatric conditions or primary cutaneous conditions with suicidal or other psychiatric risks. Adequate training of the healthcare staff is advised. The premises and time allocation should be adequate, and this translates into higher tariffs. Using business care tariffs for people with mental health conditions might be more appropriate, as the consultations are longer and involve more members of staff; however, the overall cost remains lower than if these patients were seen in a general dermatology service or in the community. Psychodermatology services are globally limited, and yet the demand for psychodermatology care is high. There is evidence that dedicated psychodermatology services are cost-effective. Healthcare professionals need to be aware of the steps necessary to establish and maintain psychodermatology services. © 2014 British Association of Dermatologists.

  9. 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...

  10. 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...

  11. Set-up of light nuclei multidetector

    International Nuclear Information System (INIS)

    Drouet, A.

    1985-01-01

    In order to study mechanisms of reactions produced by heavy ions in the GANIL energy range (15-100 MeV/A), a multidetector capable to detect large multiplicities for particles and light nuclei is necessary. The multidetector set up covers the 3-30 0 angular range and consists of 96 counters (NE102 plastic scintillator sheet, 2mm thick). The apparatus must identify the nuclear charge of the detected particles. Using the apparatus at GANIL leaded to carry out data processing tools in conversationnal mode and to write on experimental area programs performing and monitoring data acquisition. A test carried out with a 44 MeV/A argon beam showed that the apparatus was working properly: the identification in nuclear charge between Z=1 (proton) and Z=7 (nitrogen) is good. Results of the test allow to draw light production curves in the NE102 plastic scintillator for the following ions: 1 H, 4 He, 7 Li, 9 Be, 11 B, 12 C, 14 N, in the 13 to 44 MeV/A energy range [fr

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

    Science.gov (United States)

    Cai, Jun; Huai, Xiulan; Li, Xunfeng

    2009-12-01

    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 (corresponding to the saturated vapor pressure of liquid), cavitation number and inlet pressure of venturi on radial motion 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.

  13. 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

  14. Cavitation erosion - scale effect and model investigations

    Science.gov (United States)

    Geiger, F.; Rutschmann, P.

    2015-12-01

    The experimental works presented in here contribute to the clarification of erosive effects of hydrodynamic cavitation. Comprehensive cavitation erosion test series were conducted for transient cloud cavitation in the shear layer of prismatic bodies. The erosion pattern and erosion rates were determined with a mineral based volume loss technique and with a metal based pit count system competitively. The results clarified the underlying scale effects and revealed a strong non-linear material dependency, which indicated significantly different damage processes for both material types. Furthermore, the size and dynamics of the cavitation clouds have been assessed by optical detection. The fluctuations of the cloud sizes showed a maximum value for those cavitation numbers related to maximum erosive aggressiveness. The finding suggests the suitability of a model approach which relates the erosion process to cavitation cloud dynamics. An enhanced experimental setup is projected to further clarify these issues.

  15. Transition of cavitating flow to supercavitation within Venturi nozzle – hysteresis investigation

    OpenAIRE

    Jiří Kozák; Pavel Rudolf; Rostislav Huzlík; Martin Hudec; Radomír Chovanec; Ondřej Urban; Blahoslav Maršálek; Eliška Maršálková; František Pochylý; David Štefan

    2017-01-01

    Cavitation is usually considered as undesirable phenomena. On the other hand, it can be utilized in many applications. One of the technical applications is using cavitation in water treatment, where hydrodynamic cavitation seems to be effective way how to reduce cyanobacteria within large bulks of water. The main scope of this paper is investigation of the cavitation within Venturi nozzle during the transition from fully developed cavitation to supercavitation regime and vice versa. Dynamics ...

  16. Windows VPN Set Up | High-Performance Computing | NREL

    Science.gov (United States)

    Windows VPN Set Up Windows VPN Set Up To set up Windows for HPC VPN, here are the steps: Download your version of Windows. Note: We only support the the Endian Connect software when connecting to the a VPN connection to the HPC systems. Windows Version Connect App Windows 10

  17. Treatment of cyanide containing wastewater using cavitation based approach.

    Science.gov (United States)

    Jawale, Rajashree H; Gogate, Parag R; Pandit, Aniruddha B

    2014-07-01

    Industrial wastewater streams containing high concentrations of biorefractory materials like cyanides should ideally be treated at source. In the present work, degradation of potassium ferrocyanide (K4Fe(CN)6) as a model pollutant has been investigated using cavitational reactors with possible intensification studies using different approaches. Effect of different operating parameters such as initial concentration, temperature and pH on the extent of degradation using acoustic cavitation has been investigated. For the case of hydrodynamic cavitation, flow characteristics of cavitating device (venturi) have been established initially followed by the effect of inlet pressure and pH on the extent of degradation. Under the optimized set of operating parameters, the addition of hydrogen peroxide (ratio of K4Fe(CN)6:H2O2 varied from 1:1 to 1:30 mol basis) as process intensifying approach has been investigated. The present work has conclusively established that under the set of optimized operating parameters, cavitation can be effectively used for degradation of potassium ferrocyanide. The comparative study of hydrodynamic cavitation and acoustic cavitation suggested that hydrodynamic cavitation is more energy efficient and gives higher degradation as compared to acoustic cavitation for equivalent power/energy dissipation. The present work is the first one to report comparison of cavitation based treatment schemes for degradation of cyanide containing wastewaters. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Hydrodynamic Forces on Composite Structures

    Science.gov (United States)

    2014-06-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited HYDRODYNAMIC ...Thesis 4. TITLE AND SUBTITLE HYDRODYNAMIC FORCES ON COMPOSITE STRUCTURES 5. FUNDING NUMBERS 6. AUTHOR(S) Scott C. Millhouse 7. PERFORMING...angles yields different free surface effects including vortices and the onset of cavitation . 14. SUBJECT TERMS Fluid structure interaction, FSI, finite

  19. 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.

  20. Hydrodynamic cavitation to improve bulk fluid to surface mass transfer in a nonimmersed ultraviolet system for minimal processing of opaque and transparent fluid foods.

    Science.gov (United States)

    Milly, P J; Toledo, R T; Chen, J; Kazem, B

    2007-11-01

    Ultraviolet (UV)-induced chemical reactions and inactivation of microorganisms in transparent and opaque fluids are strongly dependent upon the homogenous exposure of the target species to the UV irradiation. Current UV technologies used in water disinfection and food preservation applications have limited efficacy due to suspended particles shading target species. An Ultraviolet-Shockwave Power Reactor (UV-SPR) consisting of an inner rotating rotor and a stationary quartz housing and 2 end plates was used to induce 'controlled cavitation.' Eight UV low-pressure mercury lamps spaced uniformly were installed lengthwise around the quartz housing periphery. A KI to I(3) (-)chemical dosimeter for UV was used to quantify photons received by fluid in the annular space of the SPR. UV dose (J/m(2)) increased from 97 J/m(2) at 0 rpm to over 700 J/m(2) for SPR speeds above 2400 rpm. Inactivation of E. coli 25922 in apple juice and skim milk in the UV-SPR at exit temperatures below 45 degrees C was greater than 4.5 and 3 logs, respectively. The UV-SPR system proved successful in increasing the mass transfer of transparent and opaque fluid to the UV irradiated surface.

  1. Research on axial thrust of the waterjet pump based on CFD under cavitation conditions

    Science.gov (United States)

    Shen, Z. H.; Pan, Z. Y.

    2015-01-01

    Based on RANS equations, performance of a contra-rotating axial-flow waterjet pump without hydrodynamic cavitation state had been obtained combined with shear stress transport turbulence model. Its cavitation hydrodynamic performance was calculated and analysed with mixture homogeneous flow cavitation model based on Rayleigh-Plesset equations. The results shows that the cavitation causes axial thrust of waterjet pump to drop. Furthermore, axial thrust and head cavitation characteristic curve is similar. However, the drop point of the axial thrust is postponed by 5.1% comparing with one of head, and the critical point of the axial thrust is postponed by 2.6%.

  2. Research on axial thrust of the waterjet pump based on CFD under cavitation conditions

    International Nuclear Information System (INIS)

    Shen, Z H; Pan, Z Y

    2015-01-01

    Based on RANS equations, performance of a contra-rotating axial-flow waterjet pump without hydrodynamic cavitation state had been obtained combined with shear stress transport turbulence model. Its cavitation hydrodynamic performance was calculated and analysed with mixture homogeneous flow cavitation model based on Rayleigh-Plesset equations. The results shows that the cavitation causes axial thrust of waterjet pump to drop. Furthermore, axial thrust and head cavitation characteristic curve is similar. However, the drop point of the axial thrust is postponed by 5.1% comparing with one of head, and the critical point of the axial thrust is postponed by 2.6%

  3. An Experimental Investigation of Acoustic Cavitation in Gaseous Liquids

    Science.gov (United States)

    1990-11-08

    successfully to represent cavities formed by rotating propellers and, more 3 generally, by hydrodynamic cavitation . No further improvements to Rayleigh’s theory...motivated by the increasing concern over the rapid deterioration of ship propellers. This deterioration was caused by what is now known as hydrodynamic ... cavitation . Rayleigh’s equation can be obtained by equating the 0 power at infinity and the time rate of change of the kinetic energy in an incompressible

  4. Biodiesel Production from Waste Cooking Oil Using Hydrodinamic Cavitation

    OpenAIRE

    Muhammad Supardan; Satriana Satriana; Mahlinda Mahlinda

    2013-01-01

    The aim of this research was to study biodiesel production from low cost feedstock of waste cooking oil (WCO) using hydrodynamic cavitation apparatus. A two-step processes esterification process and transesterification process using hydrodynamic cavitation for the production of biodiesel from WCO is presented. The first step is acid-catalyzed esteri-fication process for reducing free fatty acid (FFA) content of WCO and followed by base-catalyzed transesterification process for converting WCO ...

  5. Numerical investigation of cavitation flow in journal bearing geometry

    OpenAIRE

    Stücke P.; Schmidt M.; Riedel M.

    2013-01-01

    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...

  6. An experimental set-up to test heatmoisture exchangers

    NARCIS (Netherlands)

    N. Ünal (N.); J.C. Pompe (Jan); W.P. Holland (Wim); I. Gultuna; P.E.M. Huygen; K. Jabaaij (K.); C. Ince (Can); B. Saygin (B.); H.A. Bruining (Hajo)

    1995-01-01

    textabstractObjectives: The purpose of this study was to build an experimental set-up to assess continuously the humidification, heating and resistance properties of heat-moisture exchangers (HMEs) under clinical conditions. Design: The experimental set-up consists of a patient model, measurement

  7. Set-Up and Punchline as Figure and Ground

    DEFF Research Database (Denmark)

    Keisalo, Marianna Päivikki

    the two that cannot be resolved by appeal to either set-up or punchline, but traps thought between them in an ‘epistemological problem’ as comedian Louis CK put it. For comedians, set-ups and punchlines are basic tools, practical and concrete ways to create and organize material. They are also familiar...

  8. 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.

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

    International Nuclear Information System (INIS)

    Aumelas, V; Pellone, C; MaItre, T

    2010-01-01

    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.

  10. 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...... of an intermittently cavitating propeller in a wake and the pressures and forces it exerts on the shaft and on the ship hull is examined. A final chapter discusses the optimization of efficiency of compound propulsors. The authors have taken care to clearly describe physical concepts and mathematical steps. Appendices...

  11. Experimental investigation of cavitation induced air release

    Directory of Open Access Journals (Sweden)

    Kowalski Karoline

    2017-01-01

    Full Text Available Variations in cross-sectional areas may lead to pressure drops below a critical value, such that cavitation and air release are provoked in hydraulic systems. Due to a relatively slow dissolution of gas bubbles, the performance of hydraulic systems will be affected on long time scales by the gas phase. Therefore predictions of air production rates are desirable to describe the system characteristics. Existing investigations on generic geometries such as micro-orifice flows show an outgassing process due to hydrodynamic cavitation which takes place on time scales far shorter than diffusion processes. The aim of the present investigation is to find a correlation between global, hydrodynamic flow characteristics and cavitation induced undissolved gas fractions generated behind generic flow constrictions such as an orifice or venturi tube. Experimental investigations are realised in a cavitation channel that enables an independent adjustment of the pressure level upstream and downstream of the orifice. Released air fractions are determined by means of shadowgraphy imaging. First results indicate that an increased cavitation activity leads to a rapid increase in undissolved gas volume only in the choking regime. The frequency distribution of generated gas bubble size seems to depend only indirectly on the cavitation intensity driven by an increase of downstream coalescence events due to a more densely populated bubbly flow.

  12. Experimental investigation of cavitation induced air release

    Science.gov (United States)

    Kowalski, Karoline; Pollak, Stefan; Hussong, Jeanette

    Variations in cross-sectional areas may lead to pressure drops below a critical value, such that cavitation and air release are provoked in hydraulic systems. Due to a relatively slow dissolution of gas bubbles, the performance of hydraulic systems will be affected on long time scales by the gas phase. Therefore predictions of air production rates are desirable to describe the system characteristics. Existing investigations on generic geometries such as micro-orifice flows show an outgassing process due to hydrodynamic cavitation which takes place on time scales far shorter than diffusion processes. The aim of the present investigation is to find a correlation between global, hydrodynamic flow characteristics and cavitation induced undissolved gas fractions generated behind generic flow constrictions such as an orifice or venturi tube. Experimental investigations are realised in a cavitation channel that enables an independent adjustment of the pressure level upstream and downstream of the orifice. Released air fractions are determined by means of shadowgraphy imaging. First results indicate that an increased cavitation activity leads to a rapid increase in undissolved gas volume only in the choking regime. The frequency distribution of generated gas bubble size seems to depend only indirectly on the cavitation intensity driven by an increase of downstream coalescence events due to a more densely populated bubbly flow.

  13. Detection of cavitation in hydraulic turbines

    Science.gov (United States)

    Escaler, Xavier; Egusquiza, Eduard; Farhat, Mohamed; Avellan, François; Coussirat, Miguel

    2006-05-01

    An experimental investigation has been carried out in order to evaluate the detection of cavitation in actual hydraulic turbines. The methodology is based on the analysis of structural vibrations, acoustic emissions and hydrodynamic pressures measured in the machine. The proposed techniques have been checked in real prototypes suffering from different types of cavitation. In particular, one Kaplan, two Francis and one Pump-Turbine have been investigated in the field. Additionally, one Francis located in a laboratory has also been tested. First, a brief description of the general features of cavitation phenomenon is given as well as of the main types of cavitation occurring in hydraulic turbines. The work presented here is focused on the most important ones which are the leading edge cavitation due to its erosive power, the bubble cavitation because it affects the machine performance and the draft tube swirl that limits the operation stability. Cavitation detection is based on the previous understanding of the cavity dynamics and its location inside the machine. This knowledge has been gained from flow visualisations and measurements in laboratory devices such as a high-speed cavitation tunnel and a reduced scale turbine test rig. The main techniques are the study of the high frequency spectral content of the signals and of their amplitude demodulation for a given frequency band. Moreover, low frequency spectral content can also be used in certain cases. The results obtained for the various types of cavitation found in the selected machines are presented and discussed in detail in the paper. Conclusions are drawn about the best sensor, measuring location, signal processing and analysis for each type of cavitation, which serve to validate and to improve the detection techniques.

  14. 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....

  15. French scientists offered time to set up companies

    CERN Document Server

    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)

  16. 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.

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

    International Nuclear Information System (INIS)

    Rudat, Volker; Hammoud, Mohamed; Pillay, Yogin; Alaradi, Abdul Aziz; Mohamed, Adel; Altuwaijri, Saleh

    2011-01-01

    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). 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. 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. In patients where high set-up accuracy is desired, daily online verification is highly recommended

  18. 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.

  19. Accuracy in tangential breast treatment set-up

    International Nuclear Information System (INIS)

    Tienhoven, G. van; Lanson, J.H.; Crabeels, D.; Heukelom, S.; Mijnheer, B.J.

    1991-01-01

    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

  20. Cavitation studies in microgravity

    Science.gov (United States)

    Kobel, Philippe; Obreschkow, Danail; Farhat, Mohamed; Dorsaz, Nicolas; de Bosset, Aurele

    The hydrodynamic cavitation phenomenon is a major source of erosion for many industrial systems such as cryogenic pumps for rocket propulsion, fast ship propellers, hydraulic pipelines and turbines. Erosive processes are associated with liquid jets and shockwaves emission fol-lowing the cavity collapse. Yet, fundamental understanding of these processes requires further cavitation studies inside various geometries of liquid volumes, as the bubble dynamics strongly depends the surrounding pressure field. To this end, microgravity represents a unique platform to produce spherical fluid geometries and remove the hydrostatic pressure gradient induced by gravity. The goal of our first experiment (flown on ESA's parabolic flight campaigns 2005 and 2006) was to study single bubble dynamics inside large spherical water drops (having a radius between 8 and 13 mm) produced in microgravity. The water drops were created by a micro-pump that smoothly expelled the liquid through a custom-designed injector tube. Then, the cavitation bubble was generated through a fast electrical discharge between two electrodes immersed in the liquid from above. High-speed imaging allowed to analyze the implications of isolated finite volumes and spherical free surfaces on bubble evolution, liquid jets formation and shock wave dynamics. Of particular interest are the following results: (A) Bubble lifetimes are shorter than in extended liquid volumes, which could be explain by deriving novel corrective terms to the Rayleigh-Plesset equation. (B) Transient crowds of micro-bubbles (smaller than 1mm) appeared at the instants of shockwaves emission. A comparison between high-speed visualizations and 3D N-particle simulations of a shock front inside a liquid sphere reveals that focus zones within the drop lead to a significantly increased density of induced cavitation. Considering shock wave crossing and focusing may hence prove crucially useful to understand the important process of cavitation erosion

  1. 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

  2. International Symposium of Cavitation and Multiphase Flow (ISCM 2014)

    International Nuclear Information System (INIS)

    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

  3. Cavitation in holographic sQGP

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, Aleksandra [Department of Physics, University of Warsaw (Poland); Leblond, Louis [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Sinha, Aninda, E-mail: asinha@cts.iisc.ernet.in [Centre for High Energy Physics, Indian Institute of Science, C.V. Raman Avenue, Bangalore 560012 (India)

    2011-06-27

    We study the possibility of cavitation in the non-conformal N=2{sup *}SU(N) theory which is a mass deformation of N=4SU(N) Yang-Mills theory. The second order transport coefficients are known from the numerical work using AdS/CFT by Buchel and collaborators. Using these and the approach of Rajagopal and Tripuraneni, we investigate the flow equations in a (1+1)-dimensional boost invariant set up. We find that the string theory model does not exhibit cavitation before phase transition is reached. We give a semi-analytic explanation of this finding.

  4. Report of sodium cavitation

    International Nuclear Information System (INIS)

    Murai, Hitoshi; Shima, Akira; Oba, Toshisaburo; Kobayashi, Ryoji; Hashimoto, Hiroyuki

    1975-01-01

    The damage of components for LMFBRs due to sodium cavitation is serious problem. This report summarizes the following items, (1) mechanism of the incipience of sodium cavitation, (2) damage due to sodium cavitation, (3) detection method for sodium cavitation, and (4) estimation method for sodium cavitation by the comparison with water cavitation. Materials were collected from the reports on liquid metal cavitation, sodium cavitation and water cavitation published from 1965 to now. The mechanism of the incipience of sodium cavitation cavitation parameters (mean location, distributed amount or occurrence aspect and stability), experiment of causing cavitation with Venturi tube, and growth of bubbles within superheated sodium. The sodium cavitation damage was caused by magnetostriction vibration method and with Venturi tube. The state of damage was investigated with the cavitation performance of a sodium pump, and the damage was examined in view of the safety of LMFBR plants. Sodium cavitation was detected with acoustic method, radiation method, and electric method. The effect of physical property of liquid on incipient cavitation was studied. These are thermodynamic effect based on quasistatic thermal equilibrium condition and the effect of the physical property of liquid based on bubble dynamics. (Iwase, T.)

  5. 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.

  6. HYDRODYNAMIC CHARACTERISTICS OF CAVITATORS IN LIMITED FLOWS OF MADE CAVITATION

    OpenAIRE

    Колосов, Олександр Євгенович; Сівецький, Володимир Іванович; Рябцев, Геннадій Леонідович; Литвиненко, Євгеній Юрійович

    2015-01-01

    The transition to the use of two-component and multicomponent biofuels and the abandonment of traditional petroleum products is observed in many countries of the world. These areas are part of the program to ensure of energy security. As a result of research conducted by the authors earlier, the data in which the theoretical developments confirmed by practical results. This made it possible to put forward ideas that are relevant to the development of new methods for the preparation of two-com...

  7. Challenges in setting up quality control in diagnostic radiology ...

    African Journals Online (AJOL)

    Journal Home > Vol 24, No 4 (2015) >. Log in or ... Quality control (QC) on diagnostic radiology equipment form part of the fundamental requirements for the ... Inadequate cooperation by facilities management, lack of QC equipment and insufficient staff form the major challenges in setting up QC in the facilities under study.

  8. View of the WA10 set-up

    CERN Multimedia

    CERN PhotoLab

    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.

  9. 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…

  10. Automotive RF immunity test set-up analysis

    NARCIS (Netherlands)

    Coenen, M.J.; Pues, H.; Bousquet, T.; Gillon, R.; Gielen, G.; Baric, A.

    2011-01-01

    Though the automotive RF emission and RF immunity requirements are highly justifiable, the application of those requirements in an non-intended manner leads to false conclusions and unnecessary redesigns for the electronics involved. When the test results become too dependent upon the test set-up

  11. Market and Impact Study Setting Up MMX Discount Store

    OpenAIRE

    Sabina Irimie; Andreea Ionică; Virginia Băleanu; Cristina Osvath

    2008-01-01

    The paper is focused on the following elements of the impact study’s content: social and economic features of the area and the social, economic and commercial impact. Currently we witness the materialisation of the research’s results by setting up such a store MMX DISCOUNT in the town of Vulcan from the Jiu Valley

  12. Radiotherapy for breast cancer: respiratory and set-up uncertainties

    International Nuclear Information System (INIS)

    Saliou, M.G.; Giraud, P.; Simon, L.; Fournier-Bidoz, N.; Fourquet, A.; Dendale, R.; Rosenwald, J.C.; Cosset, J.M.

    2005-01-01

    Adjuvant Radiotherapy has been shown to significantly reduce locoregional recurrence but this advantage is associated with increased cardiovascular and pulmonary morbidities. All uncertainties inherent to conformal radiation therapy must be identified in order to increase the precision of treatment; misestimation of these uncertainties increases the potential risk of geometrical misses with, as a consequence, under-dosage of the tumor and/or overdosage of healthy tissues. Geometric uncertainties due to respiratory movements or set-up errors are well known. Two strategies have been proposed to limit their effect: quantification of these uncertainties, which are then taken into account in the final calculation of safety margins and/or reduction of respiratory and set-up uncertainties by an efficient immobilization or gating systems. Measured on portal films with two tangential fields. CLD (central lung distance), defined as the distance between the deep field edge and the interior chest wall at the central axis, seems to be the best predictor of set-up uncertainties. Using CLD, estimated mean set-up errors from the literature are 3.8 and 3.2 mm for the systematic and random errors respectively. These depend partly on the type of immobilization device and could be reduced by the use of portal imaging systems. Furthermore, breast is mobile during respiration with motion amplitude as high as 0.8 to 10 mm in the anteroposterior direction. Respiratory gating techniques, currently on evaluation, have the potential to reduce effect of these movements. Each radiotherapy department should perform its own assessments and determine the geometric uncertainties with respect of the equipment used and its particular treatment practices. This paper is a review of the main geometric uncertainties in breast treatment, due to respiration and set-up, and solutions proposed to limit their impact. (author)

  13. 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.

  14. Cavitational synthesis of nanostructured inorganic materials for enhanced heterogeneous catalysis

    Science.gov (United States)

    Krausz, Ivo Michael

    The synthesis of nanostructured inorganic materials by hydrodynamic cavitation processing was investigated. The goal of this work was to develop a general synthesis technique for nanostructured materials with a control over crystallite size in the 1--20 nm range. Materials with crystallite sizes in this range have shown enhanced catalytic activity compared to materials with larger crystallite sizes. Several supported and unsupported inorganic materials were studied to understand the effects of cavitation on crystallite size. Cavitation processing of calcium fluoride resulted in more spherical particles, attached to one another by melted necks. This work produced the first evidence of shock wave heating of nanostructured materials by hydrodynamic cavitation processing. Hydrodynamic cavitation synthesis of various catalytic support materials indicated that their phase composition and purity could be controlled by adjustment of the processing parameters. Zirconia/alumina supports synthesized using hydro-dynamic cavitation and calcined to 1368 K retained a high purity cubic zirconia phase, whereas classically prepared samples showed a phase transformation to monoclinic zirconia. Similarly, the synthesis of alumina resulted in materials with varying Bohmite and Bayerite contents as a function of the process parameters. High temperature calcination resulted in stable alumina supports with varying amounts of delta-, and theta-alumina. Synthesis studies of palladium and silver showed modest variations in crystallite size as a function of cavitation process parameters. Calcination resulted in larger grain materials, indicating a disappearance of intergrain boundaries. Based on these results, a new synthesis method was studied involving controlled agglomeration of small silver crystallites by hydrodynamic cavitation processing, followed by deposition on alumina. The optimal pH, concentration, and processing time for controlling the silver crystallite size in the cavitation

  15. Essential Requirements to Setting up an Aesthetic Practice

    OpenAIRE

    Sachdev, Mukta; Britto, Gillian R

    2014-01-01

    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 ...

  16. Splendidly blended: a machine learning set up for CDU control

    Science.gov (United States)

    Utzny, Clemens

    2017-06-01

    As the concepts of machine learning and artificial intelligence continue to grow in importance in the context of internet related applications it is still in its infancy when it comes to process control within the semiconductor industry. Especially the branch of mask manufacturing presents a challenge to the concepts of machine learning since the business process intrinsically induces pronounced product variability on the background of small plate numbers. In this paper we present the architectural set up of a machine learning algorithm which successfully deals with the demands and pitfalls of mask manufacturing. A detailed motivation of this basic set up followed by an analysis of its statistical properties is given. The machine learning set up for mask manufacturing involves two learning steps: an initial step which identifies and classifies the basic global CD patterns of a process. These results form the basis for the extraction of an optimized training set via balanced sampling. A second learning step uses this training set to obtain the local as well as global CD relationships induced by the manufacturing process. Using two production motivated examples we show how this approach is flexible and powerful enough to deal with the exacting demands of mask manufacturing. In one example we show how dedicated covariates can be used in conjunction with increased spatial resolution of the CD map model in order to deal with pathological CD effects at the mask boundary. The other example shows how the model set up enables strategies for dealing tool specific CD signature differences. In this case the balanced sampling enables a process control scheme which allows usage of the full tool park within the specified tight tolerance budget. Overall, this paper shows that the current rapid developments off the machine learning algorithms can be successfully used within the context of semiconductor manufacturing.

  17. Setting up and managing a remote maintenance operation for fusion

    International Nuclear Information System (INIS)

    Haist, Bernhard

    2008-01-01

    Trying to set up and manage a remote maintenance operation for a thermonuclear fusion reactor is a complex undertaking. There are many problems and challenges which need addressing. This paper tries to guide the reader through this process by composing a list of generic problems and by analysing possible solutions. The first challenge before setting up a remote maintenance operation for a fusion reactor is the systematic analysis of all the remote handling requirements. Based upon this the remote handling concept, including facility layout and equipment, can be defined. The following aspects have to be considered and incorporated into the remote handling concept: - Remote handling task development. - Remote handling task logistics and resource management. - Command, control and human-machine interface system. - Viewing and camera systems. - Virtual reality and Augmented Reality software. - Automatic path planning and collision avoidance. - Remote transfer of heavy loads. - Maintainability of RH equipment. - Reliability, redundant systems and safety. - Rationalisation and modularity in both hardware and software. - Recovery from failure modes. - Condition monitoring and fault detection/prediction. - Ability to deal with unforeseen problems. Oxford Technologies Ltd. has a proven track record in setting up and running the Remote Handling group at the JET Joint Undertaking in Culham, UK. Based on the unique experience gained at JET, Oxford Technologies Ltd. also developed the current design and remote handling concept of the ITER Hot Cell during a study in 2004. Examples of both the JET remote handling experience and the ITER Hot Cell design and layout are given throughout this paper

  18. Setting up and managing a remote maintenance operation for fusion

    International Nuclear Information System (INIS)

    Haist, B.

    2007-01-01

    Trying to set up and manage a remote maintenance operation for a thermonuclear fusion reactor is a complex undertaking. There are many problems and challenges which need addressing. This paper tries to guide the reader through this process by composing a list of generic problems and by analysing possible solutions. The first challenge before setting up a remote maintenance operation for a fusion reactor is the systematic analysis of all the remote handling requirements. Based upon this the remote handling concept, including facility layout and equipment, can be defined. The following aspects have to be considered and incorporated into the remote handling concept: - Remote handling task development - Remote handling task logistics and resource management - Command, control and human-machine interface system - Viewing and camera systems - Virtual Reality and Augmented Reality software - Automatic path planning and collision avoidance - Remote transfer of heavy loads - Maintainability of RH Equipment - Reliability, redundant systems and safety - Rationalisation and modularity in both hardware and software - Recovery from failure modes - Condition monitoring and fault detection/prediction - Ability to deal with unforeseen problems Oxford Technologies Ltd has a proven track record in setting up and running the Remote Handling group at the JET Joint Undertaking in Culham, UK. Based on the unique experience gained at JET, Oxford Technologies Ltd also developed the current design and remote handling concept of the ITER Hot Cell during a study in 2004. Examples of both the JET Remote Handling experience and the ITER Hot Cell design and layout are given throughout this paper. (orig.)

  19. Setting up and managing a remote maintenance operation for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Haist, Bernhard [Oxford Technologies Ltd., 7 Nuffield Way, Abingdon, Oxon OX14 1RJ (United Kingdom)], E-mail: Bernhard.Haist@oxfordtechnologies.co.uk

    2008-12-15

    Trying to set up and manage a remote maintenance operation for a thermonuclear fusion reactor is a complex undertaking. There are many problems and challenges which need addressing. This paper tries to guide the reader through this process by composing a list of generic problems and by analysing possible solutions. The first challenge before setting up a remote maintenance operation for a fusion reactor is the systematic analysis of all the remote handling requirements. Based upon this the remote handling concept, including facility layout and equipment, can be defined. The following aspects have to be considered and incorporated into the remote handling concept: - Remote handling task development. - Remote handling task logistics and resource management. - Command, control and human-machine interface system. - Viewing and camera systems. - Virtual reality and Augmented Reality software. - Automatic path planning and collision avoidance. - Remote transfer of heavy loads. - Maintainability of RH equipment. - Reliability, redundant systems and safety. - Rationalisation and modularity in both hardware and software. - Recovery from failure modes. - Condition monitoring and fault detection/prediction. - Ability to deal with unforeseen problems. Oxford Technologies Ltd. has a proven track record in setting up and running the Remote Handling group at the JET Joint Undertaking in Culham, UK. Based on the unique experience gained at JET, Oxford Technologies Ltd. also developed the current design and remote handling concept of the ITER Hot Cell during a study in 2004. Examples of both the JET remote handling experience and the ITER Hot Cell design and layout are given throughout this paper.

  20. 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.

    2014-01-01

    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. 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. PMID:23549527

  1. Theoretical model for cavitation erosion prediction in centrifugal pump impeller

    International Nuclear Information System (INIS)

    Rayan, M.A.; Mahgob, M.M.; Mostafa, N.H.

    1990-01-01

    Cavitation is known to have great effects on pump hydraulic and mechanical characteristics. These effects are mainly described by deviation in pump performance, increasing vibration and noise level as well as erosion of blade and casing materials. In the present work, only the hydrodynamic aspect of cavitation was considered. The efforts were directed toward the study of cavitation inception, cavity mechanics and material erosion in order to clarify the macrohydrodynamic aspects of cavitation erosive wear in real machines. As a result of this study, it was found that cavitation damage can be predicted from model data. The obtained theoretical results show good agreement with the experimental results obtained in this investigation and with results of some other investigations. The application of the findings of this work will help the design engineer in predicting the erosion rate, according to the different operating conditions. (author)

  2. Large eddy simulation of cavitating flows

    Science.gov (United States)

    Gnanaskandan, Aswin; Mahesh, Krishnan

    2014-11-01

    Large eddy simulation on unstructured grids is used to study hydrodynamic cavitation. The multiphase medium is represented using a homogeneous equilibrium model that assumes thermal equilibrium between the liquid and the vapor phase. Surface tension effects are ignored and the governing equations are the compressible Navier Stokes equations for the liquid/vapor mixture along with a transport equation for the vapor mass fraction. A characteristic-based filtering scheme is developed to handle shocks and material discontinuities in non-ideal gases and mixtures. A TVD filter is applied as a corrector step in a predictor-corrector approach with the predictor scheme being non-dissipative and symmetric. The method is validated for canonical one dimensional flows and leading edge cavitation over a hydrofoil, and applied to study sheet to cloud cavitation over a wedge. This work is supported by the Office of Naval Research.

  3. 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.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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.

  5. Numerical simulation of wall roughness effects in cavitating flow

    International Nuclear Information System (INIS)

    Echouchene, F.; Belmabrouk, H.; Le Penven, L.; Buffat, M.

    2011-01-01

    Hydrodynamic cavitation has an important effect on the performance of Diesel injectors. It influences the nature of the fuel spray and the efficiency of the combustion process. In the present study, we investigate numerically the effect of wall roughness in the cavitating and turbulent flow developing inside a Diesel injector. The mixture model based on a single fluid is adopted and the commercial Fluent software is used to solve the transport equations. The discharge coefficient C d is computed for different cavitation numbers and wall roughness heights. Profiles of density mixture, vapor volume fraction, mean velocity and turbulent kinetic energy are reported. The effects of wall roughness and injection pressure are analyzed.

  6. Set-up for pulse radiolysis of agressive substances

    International Nuclear Information System (INIS)

    Kozlowska-Milner, E.; Broszkiewicz, R.; Stanikowski, J.

    1975-01-01

    A set-up for the pulse radiolysis of aggressive substances with a relatively low consumption of the liquid, tested for anhydrous HNO 3 , has been described. The samples have been irradiated with single pulses of 10 MeV electrons at the linear accelerator type LAE 13-9. The absorption spectra of the irradiated samples (within a range of 300-800 nm) were provided by a xenon lamp. The variations of the voltage from the photomultiplier, coupled with an oscilloscope, were registered with the aid of a Polaroid camera. (T.G.)

  7. Setting up and performance of a laser enhanced ionisation spectrometer

    International Nuclear Information System (INIS)

    Chandola, L.C.; Khanna, P.P.; Razvi, M.A.N.

    1990-01-01

    A laser enhanced ionisation (LEI) spectrometer has been successfuly set up around an excimer laser pumped dye laser. The performance of the spectrometer has been tested by analysing sodium in water solutions. A straight line working curve has been obtained in the concentration range of 1-1000 ng/ml of Na. The effect of parameters like laser power, ion collector electrode voltage and the load resistance on LEI signals has been investigated. The spectrometer is useful not only for analytical purposes but also for laser spectroscopic studies of species formed in flames, study of phenomenon of combustion etc. (author). 1 tab ., 10 figs., 5 refs

  8. 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.

  9. A HPMT based set-up to characterize scintillating crystals

    International Nuclear Information System (INIS)

    D'Ambrosio, C.; Ercoli, C.; Jaaskelainen, S.; Lecoeur, G.; Leutz, H.; Loos, R.; Piedigrossi, D.; Puertolas, D.; Rosso, E.; Schomaker, R.

    1999-01-01

    We have developed a fully automatic measurement set-up, capable of measuring light yields arising from scintillating crystals in a linear range of about four orders of magnitude. The photodetector is a hybrid photomultiplier tube specially developed to optimize linear range and photon detection. Crystal and photodetector are temperature controlled by a closed water circuit, as this is essential when measuring low light yield scintillating crystals with a marked temperature dependence of their light yield. Gamma sources can be placed either on top or on the side of the crystal. In this latter case, the source can be automatically moved by a computer-controlled step motor to provide a uniformity profile of the light yield along the crystal. Tagged and not-tagged operation modes are possible. The whole set-up is computer-controlled in an effort to provide fast and reliable measurements, to characterize many crystals per day. This is important for the quality control of the lead tungstate crystals that will be applied in the electromagnetic calorimeter of the CMS-detector at the LHC at CERN. (author)

  10. A HPMT based set-up to characterize scintillating crystals

    Energy Technology Data Exchange (ETDEWEB)

    D' Ambrosio, C.; Ercoli, C.; Jaaskelainen, S.; Lecoeur, G.; Leutz, H.; Loos, R.; Piedigrossi, D.; Puertolas, D.; Rosso, E.; Schomaker, R

    1999-09-21

    We have developed a fully automatic measurement set-up, capable of measuring light yields arising from scintillating crystals in a linear range of about four orders of magnitude. The photodetector is a hybrid photomultiplier tube specially developed to optimize linear range and photon detection. Crystal and photodetector are temperature controlled by a closed water circuit, as this is essential when measuring low light yield scintillating crystals with a marked temperature dependence of their light yield. Gamma sources can be placed either on top or on the side of the crystal. In this latter case, the source can be automatically moved by a computer-controlled step motor to provide a uniformity profile of the light yield along the crystal. Tagged and not-tagged operation modes are possible. The whole set-up is computer-controlled in an effort to provide fast and reliable measurements, to characterize many crystals per day. This is important for the quality control of the lead tungstate crystals that will be applied in the electromagnetic calorimeter of the CMS-detector at the LHC at CERN. (author)

  11. 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.

  12. Ultrafast cavitation induced by an X-ray laser in water drops

    Science.gov (United States)

    Stan, Claudiu; Willmott, Philip; Stone, Howard; Koglin, Jason; Liang, Mengning; Aquila, Andrew; Robinson, Joseph; Gumerlock, Karl; Blaj, Gabriel; Sierra, Raymond; Boutet, Sebastien; Guillet, Serge; Curtis, Robin; Vetter, Sharon; Loos, Henrik; Turner, James; Decker, Franz-Josef

    2016-11-01

    Cavitation in pure water is determined by an intrinsic heterogeneous cavitation mechanism, which prevents in general the experimental generation of large tensions (negative pressures) in bulk liquid water. We developed an ultrafast decompression technique, based on the reflection of shock waves generated by an X-ray laser inside liquid drops, to stretch liquids to large negative pressures in a few nanoseconds. Using this method, we observed cavitation in liquid water at pressures below -100 MPa. These large tensions exceed significantly those achieved previously, mainly due to the ultrafast decompression. The decompression induced by shock waves generated by an X-ray laser is rapid enough to continue to stretch the liquid phase after the heterogeneous cavitation occurs in water, despite the rapid growth of cavitation nanobubbles. We developed a nucleation-and-growth hydrodynamic cavitation model that explains our results and estimates the concentration of heterogeneous cavitation nuclei in water.

  13. Transition of cavitating flow to supercavitation within Venturi nozzle - hysteresis investigation

    Science.gov (United States)

    Jiří, Kozák; Pavel, Rudolf; Rostislav, Huzlík; Martin, Hudec; Radomír, Chovanec; Ondřej, Urban; Blahoslav, Maršálek; Eliška, Maršálková; František, Pochylý; David, Štefan

    Cavitation is usually considered as undesirable phenomena. On the other hand, it can be utilized in many applications. One of the technical applications is using cavitation in water treatment, where hydrodynamic cavitation seems to be effective way how to reduce cyanobacteria within large bulks of water. The main scope of this paper is investigation of the cavitation within Venturi nozzle during the transition from fully developed cavitation to supercavitation regime and vice versa. Dynamics of cavitation was investigated using experimental data of pressure pulsations and analysis of high speed videos, where FFT of the pixel intensity and Proper Orthogonal Decomposition (POD) of the records were done to identify dominant frequencies connected with the presence of cavitation. The methodology of the high speed (HS) records semiautomated analysis using the FFT was described. Obtained results were correlated and above that the possible presence of hysteresis was discussed.

  14. Transition of cavitating flow to supercavitation within Venturi nozzle – hysteresis investigation

    Directory of Open Access Journals (Sweden)

    Jiří Kozák

    2017-01-01

    Full Text Available Cavitation is usually considered as undesirable phenomena. On the other hand, it can be utilized in many applications. One of the technical applications is using cavitation in water treatment, where hydrodynamic cavitation seems to be effective way how to reduce cyanobacteria within large bulks of water. The main scope of this paper is investigation of the cavitation within Venturi nozzle during the transition from fully developed cavitation to supercavitation regime and vice versa. Dynamics of cavitation was investigated using experimental data of pressure pulsations and analysis of high speed videos, where FFT of the pixel intensity and Proper Orthogonal Decomposition (POD of the records were done to identify dominant frequencies connected with the presence of cavitation. The methodology of the high speed (HS records semiautomated analysis using the FFT was described. Obtained results were correlated and above that the possible presence of hysteresis was discussed.

  15. Cavitation and thermal dilepton production in QGP

    International Nuclear Information System (INIS)

    Bhatt, Jitesh R.; Mishra, Hiranmaya; Sreekanth, V.

    2012-01-01

    We study the effects of bulk and shear viscosities on both hydrodynamical evolution and thermal dilepton emission rate from the QGP phase at RHIC energies. We use lattice QCD inspired parametrization for the bulk viscosity and trace anomaly (equation of state) to describe behavior of the system near the critical temperature T c . Ratio of the shear viscosity to entropy density is taken to be η/s∼1/4π. We calculate the corrections on the dilepton production rates due to modification in the distribution function, arising due to the presence of the bulk and shear viscosities. It is shown that when the system temperature evolves close to T c the effect of the bulk viscosity on the dilepton emission rates cannot be ignored. It is demonstrated that the bulk viscosity can suppress the thermal dilepton spectra where as the effect of the shear viscosity is to enhance it. Further we show that the bulk viscosity driven fragmentation or cavitation can set in very early during the hydrodynamical evolution and this in turn would make the hydrodynamical treatment invalid beyond the cavitation time. We find that even though the finite bulk viscosity corrections and the onset of the cavitation reduce the production rates, the effect of the minimal η/s=1/4π can enhance the dilepton production rates significantly in the regime p T ⩾2 GeV.

  16. Report on the set-up of a holographic interferometer

    International Nuclear Information System (INIS)

    Koster, J.N.

    1977-10-01

    Holographic interferometry is well suited for visualizing temperature, density, pressure and concentration fields in transparent fluids. The holographic real-time interferometer allows a continuous observation of stationary and instationary flow processes. After the explanation of the measuring technique, the problems arising during the interferometer set-up as well as the necessary adjusting operations are described. For heat transfer problems new possibilities for the application of holographic interferometry are revealed. Convection in boxes, temperature fields around heated or cooled bodies, concentration and diffusion processes in two phase-flows, mixtures and solutions as well as melting and freezing processes may be investigated. On the basis of particular examples some applications are presented. (orig.) [de

  17. 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.

  18. CACTUS - a multidetector set-up at the Oslo Cyclotron

    International Nuclear Information System (INIS)

    Guttormsen, M.; Bjerke, B.; Messelt, S.; Olsen, E.A.; Ramsoey, T.; Rekstad, J.; Tveter, T.S.; Wikne, J.C.; Kownacki, J.

    1989-06-01

    The design and construction of the multidetector system CACTUS is discussed, and its operation in the context of the Oslo Cyclotron is described. The multidetector system has been initiated to meet the requirements at the Oslo Cyclotron Laboratory in the experimental work on nuclear structure at high intrinsic excitation energy. The laboratory has developed a promising technique based on measuring γ-decay after single nucleon transfer reactions with the use of pγ coincidences. However, a proper interpretation of the experimental results has often been difficult due to low counting rates. One of the most important aims for the new experimental set-up has been to obtain pγ as well as pγγ coincidence spectra with high statistics. The CACTUS detector system which is mounted on the 90 o beam line of the cyclotron, consists of 28 NaI and 2 Ge detectors in combination with 8 Si particle telescopes

  19. 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.

  20. Analysis method set up to check against adulterated export honey

    International Nuclear Information System (INIS)

    Lyon, G.L.

    2001-01-01

    Over the past few years, North America has experienced occasional problems with the adulteration of honey, mainly by additions of other, cheaper sugar to increase bulk and lower production costs. The main addition was usually high fructose corn syrup, which had a similar chemical composition to that of honey. As a consequence of this type of adulteration, a method for its detection was developed using isotope ratio mass spectroscopy (IRMS). This was later refined to be more sensitive and is now specified as an Official Test. The Institute of Geological and Nuclear Sciences has now set up the analysis method to the international criteria at the Rafter Stable Isotope Laboratory in Lower Hutt. 2 refs

  1. 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.

  2. Setting up of a PIXE facility at FOTIA at BARC

    International Nuclear Information System (INIS)

    Joseph, Daisy; Saxena, A.

    2005-01-01

    PIXE-(Proton Induced X-ray Emission) -an ideal technique for material characterization has been set up at the Folded Tandem Ion Accelerator (FOTIA) at BARC, Trombay. A separate beam line at 45 deg port in which a dedicated PIXE chamber has been installed is being used for PIXE studies. PIXE studies on gold standards were carried out using protons of energy 3.3 MeV. Caritage values of gold standards were obtained which agree well with the certified values. Single element standard solutions (100 μg/ml) for low-Z elements such as Cr, Mn, Fe, Co, Cu and Zn were analyzed by PIXE. Well resolved α and β components of the x-rays were seen with detection limits in the range of 0.8-4 μg/g. (author)

  3. Localization of Manufacturing Capabilities in Setting Up Nuclear Power Plants

    International Nuclear Information System (INIS)

    Chadda, Sushil Kumar

    2011-01-01

    Nuclear renaissance is now imminent and is inevitable in view of rapidly increasing global warming concerns. A steep shift towards environmentally benign sources of energy remains an unavoidable choice as continents are warming up pushing seas into human habitation and disturbing global ecology. Accordingly, Indian government in its integrated energy policy document has planned for raising nuclear power capacity to generate 63 GWe by 2030. This envisages estimated investments of US$22 billion in the next 15 to 20 years. Setting up of nuclear energy generation capacity, however, remains a painstakingly slow process primarily due to complex, multidisciplinary efforts required to crank up a reactor. A robust supply chain remains key to expediting this process. In the light of this, it is critically important to ensure supply-chain for materials and components and putting in place cost effective project management to complete the projects on time and within the budgets. In this context, the participation of industries and their preparedness to meet the challenges are necessary. This would also require investments towards up gradation of manufacturing technology, training of manpower and mobilization of resources at the construction site. The industry would also need to enhance detailing and design engineering capabilities for the plants. It is only when such capabilities have been brought up that the possibilities of time-bound setting up of nuclear plants can be realized. In this paper, various issues with regard to project cost, regulatory and licensing, technology and gestation period etc for new build plants relevant to manufacturing industry are discussed. The plans for enhancing manufacturing capabilities for the critical path items of the project schedule with viable business, ensuring returns to stakeholders and financing and investment cycle are brought out. The various steps and initiatives being taken by Bharat Forge Ltd, the flagship company of Kalyani

  4. Magnetic spectrometer of the DEUTERON-2 set-up

    International Nuclear Information System (INIS)

    Ajvazyan, R.V.; Alanakyan, K.V.; Amaryan, M.J.

    1989-01-01

    A magnetic spectrometer of the two-arm DEUTERON-2 set-up of the Erevan Physical Institute is described. It is shown that the rejection factor for electrons and pions is 10 -2 - 10 -3 . The positively charged particles in the momentum range up to 1.5 GeV/c are identified by momentum and time-of-flight measurements. The main characteristics of the spectrometer are: momentum and angular acceptance δp/p = 46%, Δθ = 4 deg, solid angle ΔΩ = 2.75 msr, momentum resolution δp/p = 1.5%, angular resolutions δθ = 0.6 deg, δφ = 2 deg. The intervals of measured momentum and the polar scattering anlge are 0.5-3 GeV/c and 10-30 deg, 68-90 deg respectively. 7 refs.; 11 figs

  5. Characterization of Axial Inducer Cavitation Instabilities via High Speed Video Recordings

    Science.gov (United States)

    Arellano, Patrick; Peneda, Marinelle; Ferguson, Thomas; Zoladz, Thomas

    2011-01-01

    Sub-scale water tests were undertaken to assess the viability of utilizing high resolution, high frame-rate digital video recordings of a liquid rocket engine turbopump axial inducer to characterize cavitation instabilities. These high speed video (HSV) images of various cavitation phenomena, including higher order cavitation, rotating cavitation, alternating blade cavitation, and asymmetric cavitation, as well as non-cavitating flows for comparison, were recorded from various orientations through an acrylic tunnel using one and two cameras at digital recording rates ranging from 6,000 to 15,700 frames per second. The physical characteristics of these cavitation forms, including the mechanisms that define the cavitation frequency, were identified. Additionally, these images showed how the cavitation forms changed and transitioned from one type (tip vortex) to another (sheet cavitation) as the inducer boundary conditions (inlet pressures) were changed. Image processing techniques were developed which tracked the formation and collapse of cavitating fluid in a specified target area, both in the temporal and frequency domains, in order to characterize the cavitation instability frequency. The accuracy of the analysis techniques was found to be very dependent on target size for higher order cavitation, but much less so for the other phenomena. Tunnel-mounted piezoelectric, dynamic pressure transducers were present throughout these tests and were used as references in correlating the results obtained by image processing. Results showed good agreement between image processing and dynamic pressure spectral data. The test set-up, test program, and test results including H-Q and suction performance, dynamic environment and cavitation characterization, and image processing techniques and results will be discussed.

  6. Hydrodynamic optical soliton tunneling

    Science.gov (United States)

    Sprenger, P.; Hoefer, M. A.; El, G. A.

    2018-03-01

    A notion of hydrodynamic optical soliton tunneling is introduced in which a dark soliton is incident upon an evolving, broad potential barrier that arises from an appropriate variation of the input signal. The barriers considered include smooth rarefaction waves and highly oscillatory dispersive shock waves. Both the soliton and the barrier satisfy the same one-dimensional defocusing nonlinear Schrödinger (NLS) equation, which admits a convenient dispersive hydrodynamic interpretation. Under the scale separation assumption of nonlinear wave (Whitham) modulation theory, the highly nontrivial nonlinear interaction between the soliton and the evolving hydrodynamic barrier is described in terms of self-similar, simple wave solutions to an asymptotic reduction of the Whitham-NLS partial differential equations. One of the Riemann invariants of the reduced modulation system determines the characteristics of a soliton interacting with a mean flow that results in soliton tunneling or trapping. Another Riemann invariant yields the tunneled soliton's phase shift due to hydrodynamic interaction. Soliton interaction with hydrodynamic barriers gives rise to effects that include reversal of the soliton propagation direction and spontaneous soliton cavitation, which further suggest possible methods of dark soliton control in optical fibers.

  7. 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-...

  8. Secondary electron images obtained with a standard PEEM set up

    International Nuclear Information System (INIS)

    Benka, O.; Zeppenfeld, P.

    2004-01-01

    Secondary electron images excited by 3 to 4.3 keV electrons are obtained with a standard photoelectron electron emission microscope (PEEM) set up equipped with an imaging energy filter (IEF). The electron gun was mounted on a standard PEEM entrance flange at an angle of 25 o with respect to the sample surface. A low extraction voltage of 500 V was used to minimize the deflection of the electron beam by the PEEM extraction electrode. The secondary electron images are compared to photoelectron images excited by a standard 4.9 eV UV lamp. In the case of a Cu pattern on a Si substrate it is found that the lateral resolution without the IEF is about the same for electron and photon excitation but that the relative electron emission intensities are very different. The use of the IEF-reduces the lateral resolution. Images for secondary electron energies between eV 1 and eV 2 were obtained by setting the IEF to -V 1 and -V 2 ∼ -(V 1 + 5V) potentials and taking the difference of both images. Images up to 100 eV electron energies were recorded. The lateral resolution is in the range of μm. The material contrast obtained in these difference images are discussed in terms of a secondary electron and photoelectron emission model and secondary electron energy spectra measured with a LEED-Auger spectrometer. (author)

  9. Set up for simultaneous water desalination and power generation

    International Nuclear Information System (INIS)

    Hasan, S.W.; Mookhi, M.B.; Sadiq, M.A.; Hasan, Z.; Zaidi, S.I.; Shah, W.A.

    2010-01-01

    Instead of following the conventional fuel oriented power generation methods and dissipating its heat into environment, we evaporate saline water into steam and use its energy to generate power. Using this scheme would make sea water usable in power generation which at the moment is only being used for cooling purposes in the power plants. The steam used for generating electricity is eventually collected, condensed and used for potable purposes. The proposed scheme may be seen as Steam Power Generation with additional feature of desalination. We set up an experimental test bed in order to calculate the electric power available using this scheme. To ensure safety for human consumption, we also perform chemical tests on the desalinated water to see whether it is fit to be used for drinking and agricultural purposes. Our conclusions are based on actual experiments and laboratory tests; procedures outlined here may be used at larger scale for more in-depth analyses. We also highlight future extensions and modifications in this work. (author)

  10. IAEA Sets Up Team to Drive Nuclear Safety Action Plan

    International Nuclear Information System (INIS)

    2011-01-01

    Full text: The International Atomic Energy Agency is setting up a Nuclear Safety Action Team to oversee prompt implementation of the IAEA Action Plan on Nuclear Safety and ensure proper coordination among all stakeholders. The 12-point Action Plan, drawn up in the wake of the Fukushima Daiichi accident, was approved by the Agency's Board of Governors on 13 September and endorsed by all 151 Member States at its General Conference last week. The team will work within the Agency's Department of Nuclear Safety and Security, headed by Deputy Director General Denis Flory, and will coordinate closely with the Director General's Office for Policy. ''The Action Plan requires immediate follow-up,'' Director General Yukiya Amano said. ''This compact, dedicated team will assist Deputy Director General Flory in implementing the measures agreed in the Action Plan.'' Gustavo Caruso, Head of the Regulatory Activities Section in the IAEA's Division of Installation Safety, has been designated as the team's Special Coordinator for the implementation of the Action Plan. The IAEA has already started implementing its responsibilities under the Action Plan, including development of an IAEA methodology for stress tests for nuclear power plants. The methodology will be ready in October. (IAEA)

  11. 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.

  12. Numerical investigation of cavitation flow in journal bearing geometry

    Directory of Open Access Journals (Sweden)

    Stücke P.

    2013-04-01

    Full Text Available 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.

  13. Experimental evidence of temperature gradients in cavitating microflows seeded with thermosensitive nanoprobes

    Science.gov (United States)

    Ayela, Frédéric; Medrano-Muñoz, Manuel; Amans, David; Dujardin, Christophe; Brichart, Thomas; Martini, Matteo; Tillement, Olivier; Ledoux, Gilles

    2013-10-01

    Thermosensitive fluorescent nanoparticles seeded in deionized water combined with confocal microscopy enables thermal mapping over three dimensions of the liquid phase flowing through a microchannel interrupted by a microdiaphragm. This experiment reveals the presence of a strong thermal gradient up to ˜105 K/m only when hydrodynamic cavitation is present. Here hydrodynamic cavitation is the consequence of high shear rates downstream in the diaphragm. This temperature gradient is located in vortical structures associated with eddies in the shear layers. We attribute such overheating to the dissipation involved by the cavitating flow regime. Accordingly, we demonstrate that the microsizes of the device enhance the intensity of the thermal gap.

  14. A critical pressure based panel method for prediction of unsteady loading of marine propellers under cavitation

    International Nuclear Information System (INIS)

    Liu, P.; Bose, N.; Colbourne, B.

    2002-01-01

    A simple numerical procedure is established and implemented into a time domain panel method to predict hydrodynamic performance of marine propellers with sheet cavitation. This paper describes the numerical formulations and procedures to construct this integration. Predicted hydrodynamic loads were compared with both a previous numerical model and experimental measurements for a propeller in steady flow. The current method gives a substantial improvement in thrust and torque coefficient prediction over a previous numerical method at low cavitation numbers of less than 2.0, where severe cavitation occurs. Predicted pressure coefficient distributions are also presented. (author)

  15. Study on Effects of The Shape of Cavitator on Supercavitation Flow Field Characteristics

    Science.gov (United States)

    Wang, Rui; Dang, Jianjun; Yao, Zhong

    2018-03-01

    The cavitator is the key part of the nose of the vehicle to induce the formation of supercavity, which has an important influence in the cavity formation rate, cavity shape and cavity stability. To study the influence of the shape on the supercavitation flew field characteristics, the cavity characteristics and the resistance characteristics of different shapes of cavitator under different working conditions are obtained by combining technical methods of numerical simulation and experimental research in water tunnel. The simulation results are contrast and analyzed with the test results. The analysis results show that : in terms of the cavity size, the inverted-conic cavitator can form the biggest cavity size, followed by the disk cavitator, and the truncated-conic cavitator is the least; in terms of the cavity formation speed, the inverted-conic cavitator has the fastest cavity formation speed, then is the truncated-conic cavitator, and the disk cavitator is the least; in terms of the drag characteristic, the truncated-conic cavitator has the maximum coefficient, disk cavitator is the next, the inverted-conic cavitator is the minimal. The research conclusion can provide reference and basis for the head shape design of supercavitating underwater ordnance and the design of hydrodynamic layout.

  16. 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.

  17. 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.

  18. Cavitation Erosion in Hydraulic Turbine Components and Mitigation by Coatings: Current Status and Future Needs

    Science.gov (United States)

    Singh, Raghuvir; Tiwari, S. K.; Mishra, Suman K.

    2012-07-01

    Cavitation erosion is a frequently observed phenomenon in underwater engineering materials and is the primary reason for component failure. The damage due to cavitation erosion is not yet fully understood, as it is influenced by several parameters, such as hydrodynamics, component design, environment, and material chemistry. This article gives an overview of the current state of understanding of cavitation erosion of materials used in hydroturbines, coatings and coating methodologies for combating cavitation erosion, and methods to characterize cavitation erosion. No single material property fully characterizes the resistance to cavitation erosion. The combination of ultimate resilience, hardness, and toughness rather may be useful to estimate the cavitation erosion resistance of material. Improved hydrodynamic design and appropriate surface engineering practices reduce damage due to cavitation erosion. The coatings suggested for combating the cavitation erosion encompasses carbides (WC Cr2C3, Cr3C2, 20CrC-80WC), cermets of different compositions (e.g., 56W2C/Ni/Cr, 41WC/Ni/Cr/Co), intermetallic composites, intermetallic matrix composites with TiC reinforcement, composite nitrides such as TiAlN and elastomers. A few of them have also been used commercially. Thermal spraying, arc plasma spraying, and high velocity oxy-fuel (HVOF) processes have been used commercially to apply the coatings. Boronizing, laser surface hardening and cladding, chemical vapor deposition, physical vapor deposition, and plasma nitriding have been tried for surface treatments at laboratory levels and have shown promise to be used on actual components.

  19. 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).

  20. Decolourization of Rhodamine B: A swirling jet-induced cavitation combined with NaOCl.

    Science.gov (United States)

    Mancuso, Giuseppe; Langone, Michela; Laezza, Marco; Andreottola, Gianni

    2016-09-01

    A hydrodynamic cavitation reactor (Ecowirl) based on swirling jet-induced cavitation has been used in order to allow the degradation of a waste dye aqueous solution (Rhodamine B, RhB). Cavitation generated by Ecowirl reactor was directly compared with cavitation generated by using multiple hole orifice plates. The effects of operating conditions and parameters such as pressure, pH of dye solution, initial concentration of RhB and geometry of the cavitating devices on the degradation rate of RhB were discussed. In similar operative conditions, higher extents of degradation (ED) were obtained using Ecowirl reactor rather than orifice plate. An increase in the ED from 8.6% to 14.7% was observed moving from hole orifice plates to Ecowirl reactor. Intensification in ED of RhB by using hydrodynamic cavitation in presence of NaOCl as additive has been studied. It was found that the decolourization was most efficient for the combination of hydrodynamic cavitation and chemical oxidation as compared to chemical oxidation and hydrodynamic cavitation alone. The value of ED of 83.4% was reached in 37min using Ecowirl combined with NaOCl (4.0mgL(-1)) as compared to the 100min needed by only mixing NaOCl at the same concentration. At last, the energetic consumptions of the cavitation devices have been evaluated. Increasing the ED and reducing the treatment time, Ecowirl reactor resulted to be more energy efficient as compared to hole orifice plates, Venturi and other swirling jet-induced cavitation devices, as reported in literature. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Cyclotron produced radionuclides: Guidelines for setting up a facility

    International Nuclear Information System (INIS)

    2009-01-01

    Establishment of a cyclotron based radionuclide and radiopharmaceutical production facility is a major undertaking regardless of the scope and size of the facility. Regulatory demands of radiation protection and pharmaceutical manufacturing only add to the need for meticulous attention to a large number of factors in overall planning and successful implementation. Also, a significant commitment of resources, not just during the onset of the project, but also for sustained continuity further adds to the already difficult decision making process. In this publication, all these issues have been addressed and discussed conceptually for the benefit of planners and stakeholders of a new facility. The need for a clear vision and realistic scope of the programme has been repeatedly emphasized throughout this book as this aspect of project planning is absolutely vital for defining and achieving the mission and objectives of the facility. The most critical aspects in conceptualization, planning and subsequent implementation have been discussed in detail and are highlighted below as necessary actions: - Performing a feasibility study which balances wishful thinking with project viability; - Forming a task force composed of the stakeholders to evaluate strategically the various aspects of project planning to ultimately recommend the scope and objectives of the facility, and also to formulate the project plan; - Assessing the financial aspects of the project, including the set-up and operating costs of the facility through the development of business models and cost-benefit analyses; - Designing a facility and layout that encompasses the scope of the project and also takes into consideration the regulatory requirements; - Ensuring the availability of appropriately qualified and trained staff, critical for efficient and high quality operation of the facility; - Applying GMP regulations for the production of radiopharmaceutical products which are consistently safe for human use

  2. On the role of cavitation in particle collection in flotation - A critical review. II

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Z.A.; Xu, Z.H.; Finch, J.A.; Masliyah, J.H.; Chow, R.S. [Alberta Research Council, Edmonton, AB (Canada)

    2009-04-15

    Research in applying hydrodynamic cavitation to recovery of natural resources during the last decade is reviewed. The existence and formation of tiny bubbles or gas nuclei (diameter from microns down to nano sizes) in natural water were verified from both direct and in-direct measurements, providing a foundation for applying hydrodynamic cavitation to flotation systems. The interactions between tiny bubbles and fine particles in aqueous slurry were analysed. Tiny bubbles generated by hydrodynamic cavitation increased contact angle of solids and hence attachment force, bridge fine particles to form aggregates, minimize slime coating, remove oxidation layers on particle surfaces, and in hence reduce reagents consumption. Experiments revealed that the energy dissipation levels for cavity formation in a flowing liquid could be much lower than predicted, depending on the content of dissolved gases, presence of free gas nuclei and design of cavitation tubes. Application of hydrodynamic cavitation to fine and coarse particle flotation, high intensity conditioning, oil agglomeration of fine coal, and oil sands processing has confirmed the role of tiny bubbles formed by cavitation in improving recovery efficiency. Increased flotation kinetics by hydrodynamic cavitation could be attributed to a dual role: some collapsing cavity bubbles serving to break interfacial layers on particle surfaces while other cavity bubbles attaching to those freshly exposed mineral surfaces. The role of water vapor and other gases within cavity bubbles in particle-bubble attachment remains to be explored. Incorporating hydrodynamic cavitation into flotation systems to take advantage of its unique features is expected to develop the next generation of flotation machines.

  3. Highly effective degradation of selected groups of organic compounds by cavitation based AOPs under basic pH conditions.

    Science.gov (United States)

    Gągol, Michał; Przyjazny, Andrzej; Boczkaj, Grzegorz

    2018-07-01

    Cavitation has become on the most often applied methods in a number of industrial technologies. In the case of oxidation of organic pollutants occurring in the aqueous medium, cavitation forms the basis of numerous advanced oxidation processes (AOPs). This paper presents the results of investigations on the efficiency of oxidation of the following groups of organic compounds: organosulfur, nitro derivatives of benzene, BTEX, and phenol and its derivatives in a basic model effluent using hydrodynamic and acoustic cavitation combined with external oxidants, i.e., hydrogen peroxide, ozone and peroxone. The studies revealed that the combination of cavitation with additional oxidants allows 100% oxidation of the investigated model compounds. However, individual treatments differed with respect to the rate of degradation. Hydrodynamic cavitation aided by peroxone was found to be the most effective treatment (100% oxidation of all the investigated compounds in 60 min). When using hydrodynamic and acoustic cavitation alone, the effectiveness of oxidation was diversified. Under these conditions, nitro derivatives of benzene and phenol and its derivatives were found to be resistant to oxidation. In addition, hydrodynamic cavitation was found to be more effective in degradation of model compounds than acoustic cavitation. The results of investigations presented in this paper compare favorably with the investigations on degradation of organic contaminants using AOPs under conditions of basic pH published thus far. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Cavitation in flow through a micro-orifice inside a silicon microchannel

    Science.gov (United States)

    Mishra, Chandan; Peles, Yoav

    2005-01-01

    Hydrodynamic cavitation in flows through a micro-orifice entrenched in a microchannel has been detected and experimentally investigated. Microfabrication techniques have been employed to design and develop a microfluidic device containing an 11.5μm wide micro-orifice inside a 100.2μm wide and 101.3μm deep microchannel. The flow of de-ionized water through the micro-orifice reveals the presence of multifarious cavitating flow regimes. This investigation divulges both similarities and differences between cavitation in micro-orifices and cavitation in their macroscale counterparts. The low incipient cavitation number obtained from the current experiments suggests a dominant size scale effect. Choking cavitation is observed to be independent of any pressure or velocity scale effects. However, choking is significantly influenced by the small stream nuclei residence time at such scales. Flow rate choking leads to the establishment of a stationary cavity. Large flow and cavitation hysteresis have been detected at the microscale leading to very high desinent cavitation numbers. The rapid transition from incipient bubbles to choking cavitation and subsequent supercavitation suggests the presence of radically different flow patterns at the microscale. Supercavitation results in a thick cavity, which extends throughout the microchannel, and is encompassed by the liquid. Cavitation at the microscale is expected to considerably influence the design of innovative high-speed microfluidic systems.

  5. Observations and Measurements on Unsteady Cloud Cavitation Flow Structures

    Science.gov (United States)

    Gu, L. X.; Yan, G. J.; Huang, B.

    2015-12-01

    The objectives of this paper are to investigate the unsteady structures and hydrodynamics of cavitating flows. Experimental results are presented for a Clark-Y hydrofoil, which is fixed at α=0°, 5° and 8°. The high-speed video camera and Particle Image Velocimetry (PIV) are applied to investigate the transient flow structures. The dynamic measurement system is used to record the dynamic characteristics. The cloud cavitation exhibits noticeable unsteady characteristics. For the case of α=0°, there exit strong interactions between the attached cavity and the re-entrant flow. While for the case of α=8°, the re-entrant flow is relatively thin and the interaction between the cavity and re-entrant flow is limited. The results also present that the periodic collapse and shedding of the large-scale cloud cavitation, which leads to substantial increase of turbulent velocity fluctuations in the cavity region. Experimental evidence indicates that the hydrodynamics are clearly affected by the cavitating flow structures, the amplitude of load fluctuation are much higher for the cloud cavitating cases.

  6. Observations and Measurements on Unsteady Cloud Cavitation Flow Structures

    International Nuclear Information System (INIS)

    Gu, L X; Yan, G J; Huang, B

    2015-01-01

    The objectives of this paper are to investigate the unsteady structures and hydrodynamics of cavitating flows. Experimental results are presented for a Clark-Y hydrofoil, which is fixed at α=0°, 5° and 8°. The high-speed video camera and Particle Image Velocimetry (PIV) are applied to investigate the transient flow structures. The dynamic measurement system is used to record the dynamic characteristics. The cloud cavitation exhibits noticeable unsteady characteristics. For the case of α=0°, there exit strong interactions between the attached cavity and the re-entrant flow. While for the case of α=8°, the re-entrant flow is relatively thin and the interaction between the cavity and re-entrant flow is limited. The results also present that the periodic collapse and shedding of the large-scale cloud cavitation, which leads to substantial increase of turbulent velocity fluctuations in the cavity region. Experimental evidence indicates that the hydrodynamics are clearly affected by the cavitating flow structures, the amplitude of load fluctuation are much higher for the cloud cavitating cases. (paper)

  7. 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.

  8. Set-up for steam generator tube bundle washing after explosion expanding the tubes

    International Nuclear Information System (INIS)

    Osipov, S.I.; Kal'nin, A.Ya.; Mazanenko, M.F.

    1985-01-01

    Set-up for steam generator tube bundle washing after the explosion expanding of tubes is described. Washing is accomplished by distillate. Steam is added to distillate for heating, and compersed air for preventing hydraulic shock. The set-up is equiped by control equipment. Set-up performances are presented. Time for one steam generator washing constitutes 8-12 h. High economic efficiency is realized due to the set-up introduction

  9. Experimental Study of Cavitation in Laminar Flow

    OpenAIRE

    Croci , Kilian; Ravelet , Florent; ROBINET , Jean-Christophe; Danlos , Amélie

    2017-01-01

    An experimental setup has been especially developed in order to observe cavitation in laminar flows. Experiments have been carried out with a silicon oil of viscosity υ = 100cSt passing through a Venturi-type geometry with 18°/8° convergent/divergent angles respectively. The range of Reynolds numbers at the inlet section is between 350 and 1000. Two dynamic regimes are identified. They are characterized by two critical Reynolds numbers, induced by major hydrodynamic changes in the flow, in ad...

  10. Experimental investigation of a cavitating backward-facing step flow

    International Nuclear Information System (INIS)

    Maurice, G; Djeridi, H; Barre, S

    2014-01-01

    The present study is the first part of global experimental work which is intended to produce a refined database of liquid and vapor phases and to improve CFD modeling of turbulent cavitating flows which can occur in rocket engine turbo-pump inducers. The purpose of the present experimental study is to get a better understanding of the dynamics of the liquid phase in a cavitating backward facing step flow and provide a refined database for the physical analysis of interaction between turbulence and cavitation. The backward facing step flow provides us a well-known test case to compare vortex dynamics and a realistic industrial configuration such as backflow in turbo machinery. Experiments were conducted in the hydrodynamic tunnel of CREMHyG at Grenoble,which was especially designed to study cavitating shear flows at high Reynolds numbers. To highlight the liquid phase topology and dynamics such as large vortex structures, free shear layer instability, reattachment wall interaction and reverse flow, the flow is characterized by Laser Induced Fluoresence Particles Image Velocimetry (PIV-LIF) measurements techniques and by Laser Doppler Velocimetry (LDV) techniques using spectral analysis to characterize the vortex shedding dynamics. The liquid phase was analyzed at different cavitation levels corresponding to 1% to 45% of void ratio range inside the shear layer, recirculation area and reattachment zone. The mean and fluctuating liquid velocities are clearly modified by the vapor phase and the scale of the vortical structures tends to be smaller inducing a destructuration of turbulence by cavitation

  11. Installing and Setting Up Git Software Tool on Windows | High-Performance

    Science.gov (United States)

    Computing | NREL Git Software Tool on Windows Installing and Setting Up Git Software Tool on Windows Learn how to set up the Git software tool on Windows for use with the Peregrine system. Git is this doc, we'll show you how to get git installed on Windows 7, and how to get things set up on NREL's

  12. Cavitation damage of ceramics

    International Nuclear Information System (INIS)

    Kovalenko, V.I.; Marinin, V.G.

    1988-01-01

    Consideration is given to results of investigation of ceramic material damage under the effect of cavitation field on their surface, formed in water under the face of exponential concentrator, connected with ultrasonic generator UZY-3-0.4. Amplitude of vibrations of concentrator face (30+-2)x10 -6 m, frequency-21 kHz. It was established that ceramics resistance to cavitation effect correlated with the product of critical of stress intensity factor and material hardness

  13. Inducer Hydrodynamic Load Measurement Devices

    Science.gov (United States)

    Skelley, Stephen E.; Zoladz, Thomas F.

    2002-01-01

    Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This "rotating balance" was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

  14. 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.

  15. Cavitation guide for control valves

    International Nuclear Information System (INIS)

    Tullis, J.P.

    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

  16. Numerical simulation of wall roughness effects in cavitating flow

    Energy Technology Data Exchange (ETDEWEB)

    Echouchene, F. [Laboratoire d' electronique et de microelectronique, Departement de Physique, Faculte des Sciences de Monastir, 5000 (Tunisia); Belmabrouk, H., E-mail: frchouchene@yahoo.fr [Laboratoire d' electronique et de microelectronique, Departement de Physique, Faculte des Sciences de Monastir, 5000 (Tunisia); Le Penven, L.; Buffat, M. [LMFA UMR CNRS 5509, Universite de Claude Bernard Lyon 1, Ecole Centrale de Lyon, INSA de Lyon (France)

    2011-10-15

    Hydrodynamic cavitation has an important effect on the performance of Diesel injectors. It influences the nature of the fuel spray and the efficiency of the combustion process. In the present study, we investigate numerically the effect of wall roughness in the cavitating and turbulent flow developing inside a Diesel injector. The mixture model based on a single fluid is adopted and the commercial Fluent software is used to solve the transport equations. The discharge coefficient C{sub d} is computed for different cavitation numbers and wall roughness heights. Profiles of density mixture, vapor volume fraction, mean velocity and turbulent kinetic energy are reported. The effects of wall roughness and injection pressure are analyzed.

  17. Cavitation problems in sodium valves

    International Nuclear Information System (INIS)

    Elie, X.

    1976-01-01

    Cavitation poses few problems for sodium valves, in spite of the fact that the loops are not pressurized. This is no doubt due to the low flow velocities in the pipes. For auxiliary loop valves we are attempting to standardize performances with respect to cavitation. For economic reasons cavitation thresholds are approached with large diameter valves. (author)

  18. 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

  19. A novel ultrasonic cavitation enhancer

    NARCIS (Netherlands)

    Fernandez Rivas, David; Verhaagen, B.; Galdamez Perez, Andres; Castro-Hernandez, Elena; van Zwieten, 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

  20. 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.

  1. Modeling cavitation in a rapidly changing pressure field - application to a small ultrasonic horn.

    Science.gov (United States)

    Žnidarčič, Anton; Mettin, Robert; Dular, Matevž

    2015-01-01

    Ultrasonic horn transducers are frequently used in applications of acoustic cavitation in liquids. It has been observed that if the horn tip is sufficiently small and driven at high amplitude, cavitation is very strong, and the tip can be covered entirely by the gas/vapor phase for longer time intervals. A peculiar dynamics of the attached cavity can emerge with expansion and collapse at a self-generated frequency in the subharmonic range, i.e. below the acoustic driving frequency. The term "acoustic supercavitation" was proposed for this type of cavitation Žnidarčič et al. (2014) [1]. We tested several established hydrodynamic cavitation models on this problem, but none of them was able to correctly predict the flow features. As a specific characteristic of such acoustic cavitation problems lies in the rapidly changing driving pressures, we present an improved approach to cavitation modeling, which does not neglect the second derivatives in the Rayleigh-Plesset equation. Comparison with measurements of acoustic supercavitation at an ultrasonic horn of 20kHz frequency revealed a good agreement in terms of cavity dynamics, cavity volume and emitted pressure pulsations. The newly developed cavitation model is particularly suited for simulation of cavitating flow in highly fluctuating driving pressure fields. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Setting up and Running a School Library. Information Collection and Exchange Publication No. ED204

    Science.gov (United States)

    Baird, Nicola

    2012-01-01

    This book explains how teachers can set up and run a successful school library. In it you will find advice and information on how to: (1) set up a small library and build bookshelves; (2) select books for your library; (3) make a written record of your school's books, pamphlets and other library stock such as newspapers, magazines, audio tapes and…

  3. Realization of an automatic set up to measure electrical characteristic of solid state detectors

    International Nuclear Information System (INIS)

    Manfredotti, C.; Crosetto, D.; Gabutti, A.; Gervino, G.; Varesio, R.

    1986-01-01

    An automatic set-up is described to study electrical properties of silicon detectors for nuclear research. Particularly, I-V characteristics from silicon junction prototype detectors and amorphous samples to test the data acquisition system, are presented. This set-up joins a low cost to good versatility that makes it very useful in wide application ranges in silicon detector electrical characterization

  4. VITEX 2016 : Evaluation of learning objectives and exercise set-up

    NARCIS (Netherlands)

    Rijk, R. van; Stubbé-Alberts, H.E.

    2016-01-01

    To strengthen awareness of the need for cooperation, between public and private partners, and between countries, a new exercise set-up was developed. The VITEX exercise set-up is a table top exercise that aims to bring relevant networks together, and supports cooperation and collaboration between

  5. An experimental set-up to test heat-moisture exchangers

    NARCIS (Netherlands)

    Unal, N.; Pompe, J. C.; Holland, W. P.; Gültuna, I.; Huygen, P. E.; Jabaaij, K.; Ince, C.; Saygin, B.; Bruining, H. A.

    1995-01-01

    The purpose of this study was to build an experimental set-up to assess continuously the humidification, heating and resistance properties of heat-moisture exchangers (HMEs) under clinical conditions. The experimental set-up consists of a patient model, measurement systems and a ventilator. Surgical

  6. Determining the hydrodynamic indices of contractions

    International Nuclear Information System (INIS)

    Blagov, Eh.E.

    2002-01-01

    The new dependences, making it possible only by measuring the flow rate and pressure drop on the contraction device (CD) with the known geometry, including the regulatory organ, in the non-crisis mode of the turbulent flow to calculate all the hydrodynamic indices of this device, including the pressure reduction in the jet contraction, are obtained. This simplifies and accelerates the CD hydraulic tests of all types. The new methodology for determining the cavitation factual start on the CD is proposed [ru

  7. Mechanism of cavitation damage and structure of a cavitating eddy

    International Nuclear Information System (INIS)

    Efimov, A.V.; Vorob'ev, G.A.; Filenko, Yu.I.; Petrov, K.N.

    1976-01-01

    As a result of experimental studies of the structure of a cavitating eddy and the action of single cavitation bubbles on a solid surface the assumption of double nature of cavitation damage forces depending on its regimes was made. The first type of the damage forces is shock waves, appearing around collapsing spherical bubble, the second type is hydraulic impacts of microjets making a hole in a collapsing aspherical bubble. The outward appearance of single microdents differs from each other. The damage of the first type is accompanied by corrosion. The cavitation erosion intensity of the damage of the first type exceeds that of the damage of the second type by one order of magnitude. The values of the porosity of a cavitation eddy, the bubble concentration and the distance between them, the bubble distribution according to the size and the form for the initial cavitation stage are given from holographic investigations

  8. 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!

  9. Hydrodynamics automatic optimization of runner blades for reaction hydraulic turbines

    Science.gov (United States)

    Balint, D.; Câmpian, V.; Nedelcu, D.; Megheles, O.

    2012-11-01

    The aim of this paper is to optimize the hydrodynamics of the runner blades of hydraulic turbines. The runner presented is an axial Kaplan one, but the methodology is common also to Francis runners. The whole methodology is implemented in the in-house software QTurbo3D. The effect of the runner blades geometry modification upon its hydrodynamics is shown both from energetic and cavitation points of view.

  10. Hydrodynamics automatic optimization of runner blades for reaction hydraulic turbines

    International Nuclear Information System (INIS)

    Balint, D; Câmpian, V; Nedelcu, D; Megheles, O

    2012-01-01

    The aim of this paper is to optimize the hydrodynamics of the runner blades of hydraulic turbines. The runner presented is an axial Kaplan one, but the methodology is common also to Francis runners. The whole methodology is implemented in the in-house software QTurbo3D. The effect of the runner blades geometry modification upon its hydrodynamics is shown both from energetic and cavitation points of view.

  11. Evaluation of rotational set-up errors in patients with thoracic neoplasms

    International Nuclear Information System (INIS)

    Wang Yanyang; Fu Xiaolong; Xia Bing; Fan Min; Yang Huanjun; Ren Jun; Xu Zhiyong; Jiang Guoliang

    2010-01-01

    Objective: To assess the rotational set-up errors in patients with thoracic neoplasms. Methods: 224 kilovoltage cone-beam computed tomography (KVCBCT) scans from 20 thoracic tumor patients were evaluated retrospectively. All these patients were involved in the research of 'Evaluation of the residual set-up error for online kilovoltage cone-beam CT guided thoracic tumor radiation'. Rotational set-up errors, including pitch, roll and yaw, were calculated by 'aligning the KVCBCT with the planning CT, using the semi-automatic alignment method. Results: The average rotational set-up errors were -0.28 degree ±1.52 degree, 0.21 degree ± 0.91 degree and 0.27 degree ± 0.78 degree in the left-fight, superior-inferior and anterior-posterior axis, respectively. The maximal rotational errors of pitch, roll and yaw were 3.5 degree, 2.7 degree and 2.2 degree, respectively. After correction for translational set-up errors, no statistically significant changes in rotational error were observed. Conclusions: The rotational set-up errors in patients with thoracic neoplasms were all small in magnitude. Rotational errors may not change after the correction for translational set-up errors alone, which should be evaluated in a larger sample future. (authors)

  12. 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.

  13. Influence of Daily Set-Up Errors on Dose Distribution During Pelvis Radiotherapy

    International Nuclear Information System (INIS)

    Kasabasic, M.; Ivkovic, A.; Faj, D.; Rajevac, V.; Sobat, H.; Jurkovic, S.

    2011-01-01

    An external beam radiotherapy (EBRT) using megavoltage beam of linear accelerator is usually the treatment of choice for the cancer patients. The goal of EBRT is to deliver the prescribed dose to the target volume, with as low as possible dose to the surrounding healthy tissue. A large number of procedures and different professions involved in radiotherapy process, uncertainty of equipment and daily patient set-up errors can cause a difference between the planned and delivered dose. We investigated a part of this difference caused by daily patient set-up errors. Daily set-up errors for 35 patients were measured. These set-up errors were simulated on 5 patients, using 3D treatment planning software XiO (CMS Inc., St. Louis, MO). The differences in dose distributions between the planned and shifted ''geometry'' were investigated. Additionally, an influence of the error on treatment plan selection was checked by analyzing the change in dose volume histograms, planning target volume conformity index (CI P TV) and homogeneity index (HI). Simulations showed that patient daily set-up errors can cause significant differences between the planned and actual dose distributions. Moreover, for some patients those errors could influence the choice of treatment plan since CI P TV fell under 97 %. Surprisingly, HI was not as sensitive as CI P TV on set-up errors. The results showed the need for minimizing daily set-up errors by quality assurance programme. (author)

  14. Electronic portal image assisted reduction of systematic set-up errors in head and neck irradiation

    International Nuclear Information System (INIS)

    Boer, Hans C.J. de; Soernsen de Koste, John R. van; Creutzberg, Carien L.; Visser, Andries G.; Levendag, Peter C.; Heijmen, Ben J.M.

    2001-01-01

    Purpose: To quantify systematic and random patient set-up errors in head and neck irradiation and to investigate the impact of an off-line correction protocol on the systematic errors. Material and methods: Electronic portal images were obtained for 31 patients treated for primary supra-glottic larynx carcinoma who were immobilised using a polyvinyl chloride cast. The observed patient set-up errors were input to the shrinking action level (SAL) off-line decision protocol and appropriate set-up corrections were applied. To assess the impact of the protocol, the positioning accuracy without application of set-up corrections was reconstructed. Results: The set-up errors obtained without set-up corrections (1 standard deviation (SD)=1.5-2 mm for random and systematic errors) were comparable to those reported in other studies on similar fixation devices. On an average, six fractions per patient were imaged and the set-up of half the patients was changed due to the decision protocol. Most changes were detected during weekly check measurements, not during the first days of treatment. The application of the SAL protocol reduced the width of the distribution of systematic errors to 1 mm (1 SD), as expected from simulations. A retrospective analysis showed that this accuracy should be attainable with only two measurements per patient using a different off-line correction protocol, which does not apply action levels. Conclusions: Off-line verification protocols can be particularly effective in head and neck patients due to the smallness of the random set-up errors. The excellent set-up reproducibility that can be achieved with such protocols enables accurate dose delivery in conformal treatments

  15. An experimental set-up to measure Light Yield of Scintillating Fibres

    CERN Document Server

    Alfieri, C; Joram, C; Kenzie, M W

    2015-01-01

    In the context of the LHCb SciFi Tracker project, an experimental set up was designed and built to provide reliable and reproducible measurements of the light yield of scintillating fibres. This document describes the principle and technical realisation of the set-up. A few examples illustrate the operation and data analysis. In the first implementation of the set-up a photomultiplier tube with bialkali photocathode was used for the reading of the light from the fibres under test. In order to measure also green emitting fibres, the photomultiplier was replaced in January 2016 by a SiPM with higher sensitivity and larger spectral coverage1.

  16. 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

  17. Attached cavitation at a small diameter ultrasonic horn tip

    Science.gov (United States)

    Žnidarčič, Anton; Mettin, Robert; Cairós, Carlos; Dular, Matevž

    2014-02-01

    Ultrasonic horn transducers are frequently used in applications of acoustic cavitation in liquids, for instance, for cell disruption or sonochemical reactions. They are operated typically in the frequency range up to about 50 kHz and have tip diameters from some mm to several cm. It has been observed that if the horn tip is sufficiently small and driven at high amplitude, cavitation is very strong, and the tip can be covered entirely by the gas/vapor phase for longer time intervals. A peculiar dynamics of the attached cavity can emerge with expansion and collapse at a self-generated frequency in the subharmonic range, i.e., below the acoustic driving frequency. Here, we present a systematic study of the cavitation dynamics in water at a 20 kHz horn tip of 3 mm diameter. The system was investigated by high-speed imaging with simultaneous recording of the acoustic emissions. Measurements were performed under variation of acoustic power, air saturation, viscosity, surface tension, and temperature of the liquid. Our findings show that the liquid properties play no significant role in the dynamics of the attached cavitation at the small ultrasonic horn. Also the variation of the experimental geometry, within a certain range, did not change the dynamics. We believe that the main two reasons for the peculiar dynamics of cavitation on a small ultrasonic horn are the higher energy density on a small tip and the inability of the big tip to "wash" away the gaseous bubbles. Calculation of the somewhat adapted Strouhal number revealed that, similar to the hydrodynamic cavitation, values which are relatively low characterize slow cavitation structure dynamics. In cases where the cavitation follows the driving frequency this value lies much higher - probably at Str > 20. In the spirit to distinguish the observed phenomenon with other cavitation dynamics at ultrasonic transducer surfaces, we suggest to term the observed phenomenon of attached cavities partly covering the full horn

  18. Hydrodynamical tests with an original PWR heat removal pump

    International Nuclear Information System (INIS)

    Wietstock, P.

    1984-01-01

    GKSS-Forschungszentrum performes hydrodynamical tests with an original PWR heat removal pump to analyse the influences of fluid parameters on the capacity and cavitation behavior of the pump in order to get further improvements of the quantification of the reached safety-level. It can be concluded, that in case of the tested heat removal pump the additional loads during transition from cavitation free operation into fully cavitation for the investigated operation point with 980 m 3 /h will be smaller than the alteration of loads during passing through the total characteristic. The results from cavitation tests for other operation points indicate, that this very important consequence especially for accident operation will be valid for the total specified pump flow area. (orig.)

  19. Cavitation noise from butterfly valves

    International Nuclear Information System (INIS)

    Rahmeyer, W.J.

    1982-01-01

    Cavitation in valves can produce levels of intense noise. It is possible to mathematically express a limit for a design level of cavitation noise in terms of the cavitation parameter sigma. Using the cavitation parameter or limit, it is then possible to calculate the flow conditions at which a design level of cavitation noise will occur. However, the intensity of cavitation increases with the upstream pressure and valve size at a constant sigma. Therefore, it is necessary to derive equations to correct or scale the cavitation limit for the effects of different upstream pressures and valve sizes. The following paper discusses and presents experimental data for the caviation noise limit as well as the cavitation limits of incipient, critical, incipient damage, and choking cavitation for butterfly valves. The main emphasis is on the design limit of caviation noise, and a noise level of 85 decibels was selected as the noise limit. Tables of data and scaling exponents are included for applying the design limits for the effects of upstream pressure and valve size. (orig.)

  20. Mapping Suitable Sites for Setting up Wind Farms: A Case Study of ...

    African Journals Online (AJOL)

    Mapping Suitable Sites for Setting up Wind Farms: A Case Study of Nyanga District. ... Ethiopian Journal of Environmental Studies and Management ... sources and continuous power shortages make wind energy a very attractive alternative to ...

  1. An evaluation system of the setting up of predictive maintenance programmes

    International Nuclear Information System (INIS)

    Carnero, MaCarmen

    2006-01-01

    Predictive Maintenance can provide an increase in safety, quality and availability in industrial plants. However, the setting up of a Predictive Maintenance Programme is a strategic decision that until now has lacked analysis of questions related to its setting up, management and control. In this paper, an evaluation system is proposed that carries out the decision making in relation to the feasibility of the setting up. The evaluation system uses a combination of tools belonging to operational research such as: Analytic Hierarchy Process, decision rules and Bayesian tools. This system is a help tool available to the managers of Predictive Maintenance Programmes which can both increase the number of Predictive Maintenance Programmes set up and avoid the failure of these programmes. The Evaluation System has been tested in a petrochemical plant and in a food industry

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

    International Nuclear Information System (INIS)

    Mahdi, M.; Ebrahimi, R.; Shams, M.

    2011-01-01

    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.

  3. Feasibility of geometrical verification of patient set-up using body contours and computed tomography data

    International Nuclear Information System (INIS)

    Ploeger, Lennert S.; Betgen, Anja; Gilhuijs, Kenneth G.A.; Herk, Marcel van

    2003-01-01

    Background and purpose: Body contours can potentially be used for patient set-up verification in external-beam radiotherapy and might enable more accurate set-up of patients prior to irradiation. The aim of this study is to test the feasibility of patient set-up verification using a body contour scanner. Material and methods: Body contour scans of 33 lung cancer and 21 head-and-neck cancer patients were acquired on a simulator. We assume that this dataset is representative for the patient set-up on an accelerator. Shortly before acquisition of the body contour scan, a pair of orthogonal simulator images was taken as a reference. Both the body contour scan and the simulator images were matched in 3D to the planning computed tomography scan. Movement of skin with respect to bone was quantified based on an analysis of variance method. Results: Set-up errors determined with body-contours agreed reasonably well with those determined with simulator images. For the lung cancer patients, the average set-up errors (mm)±1 standard deviation (SD) for the left-right, cranio-caudal and anterior-posterior directions were 1.2±2.9, -0.8±5.0 and -2.3±3.1 using body contours, compared to -0.8±3.2, -1.0±4.1 and -1.2±2.4 using simulator images. For the head-and-neck cancer patients, the set-up errors were 0.5±1.8, 0.5±2.7 and -2.2±1.8 using body contours compared to -0.4±1.2, 0.1±2.1, -0.1±1.8 using simulator images. The SD of the set-up errors obtained from analysis of the body contours were not significantly different from those obtained from analysis of the simulator images. Movement of the skin with respect to bone (1 SD) was estimated at 2.3 mm for lung cancer patients and 1.7 mm for head-and-neck cancer patients. Conclusion: Measurement of patient set-up using a body-contouring device is possible. The accuracy, however, is limited by the movement of the skin with respect to the bone. In situations where the error in the patient set-up is relatively large, it is

  4. Application of video imaging for improvement of patient set-up

    International Nuclear Information System (INIS)

    Ploeger, Lennert S.; Frenay, Michel; Betgen, Anja; Bois, Josien A. de; Gilhuijs, Kenneth G.A.; Herk, Marcel van

    2003-01-01

    Background and purpose: For radiotherapy of prostate cancer, the patient is usually positioned in the left-right (LR) direction by aligning a single marker on the skin with the projection of a room laser. The aim of this study is to investigate the feasibility of a room-mounted video camera in combination with previously acquired CT data to improve patient set-up along the LR axis. Material and methods: The camera was mounted in the treatment room at the caudal side of the patient. For 22 patients with prostate cancer 127 video and portal images were acquired. The set-up error determined by video imaging was found by matching video images with rendered CT images using various techniques. This set-up error was retrospectively compared with the set-up error derived from portal images. It was investigated whether the number of corrections based on portal imaging would decrease if the information obtained from the video images had been used prior to irradiation. Movement of the skin with respect to bone was quantified using an analysis of variance method. Results: The measurement of the set-up error was most accurate for a technique where outlines and groins on the left and right side of the patient were delineated and aligned individually to the corresponding features extracted from the rendered CT image. The standard deviations (SD) of the systematic and random components of the set-up errors derived from the portal images in the LR direction were 1.5 and 2.1 mm, respectively. When the set-up of the patients was retrospectively adjusted based on the video images, the SD of the systematic and random errors decreased to 1.1 and 1.3 mm, respectively. From retrospective analysis, a reduction of the number of set-up corrections (from nine to six corrections) is expected when the set-up would have been adjusted using the video images. The SD of the magnitude of motion of the skin of the patient with respect to the bony anatomy was estimated to be 1.1 mm. Conclusion: Video

  5. Experimental and numerical research on cavitating flows around axisymmetric bodies

    International Nuclear Information System (INIS)

    Haipeng, Wei; Song, Fu; Qin, Wu; Biao, Huang; Guoyu, Wang

    2014-01-01

    We investigated the cavitating flows around different axisymmetric bodies based on experiments and numerical simulation. In the numerical simulation, the multiphase Reynolds averaged Navier Stokes equations (RANS) were solved via the commercial computational fluid dynamics code CFX. The modified k-wSST turbulence model was used along with the transport equation-based cavitation model. In the experiments, a high-speed video technique was used to observe the unsteady cavitating flow patterns, and the dynamic force measurement system was used to measure the hydrodynamics of the axisymmetric bodies under different cavitation conditions. Results are shown for the hemisphere bodies, conical bodies and blunt bodies. Reasonable agreements were obtained between the computational and experimental results. The results show that for the hemispherical body, the cavity consists of quasi-steady transparent region and unsteady foggy water-vapor mixture region, which contains small-scale vortices and is dominated by bubble clusters, causing irregular disturbances at the cavity interfaces. The curvature at the front of the conical body is larger, resulting in that the flow separates at the shoulder of the axisymmetric body. The cavity stretches downstream and reaches to a fixed cavity length and shape. For blunt bodies, the incipient cavitation number is larger than that for the hemispherical body. A large cloud cavity is formed at the shoulder of the blunt body in the cores of vortices in high shear separation regions and the re-entrant jet does not significantly interact with the cavity interface when it moves upstream. As to the dynamic characteristics of unsteady cavitating flows around the axisymmetric bodies, the pulsation frequency for the hemispherical body is larger than that for the blunt body. For the hemispherical body, the pulsation is mainly caused by the high-frequency, small-scale shedding at the rear end of the cavity, while for the blunt body, the main factor for

  6. Investigation of cavitating flows by X-ray and optical imaging

    Science.gov (United States)

    Coutier-Delgosha, Olivier; Fuzier, Sylvie; Khlifa, Ilyass; Fezzaa, Kamel

    2015-11-01

    Hydrodynamic cavitation is the partial vaporization of high speed liquid flows. The turbulent, compressible and unsteady character of these flows makes their study unusually complex and challenging. Instabilities generated by the occurrence of cavitation have been investigated in the last years in the LML laboratory by various non-intrusive measurements including X-ray imaging (to obtain the fields of void fraction and velocity in both phases), and PIV with fluorescent particles (to obtain the velocity fields in both phases). It has been shown that cavitation is characterized by significant slip velocities between liquid and vapor, especially in the re-entrant jet area and the cavity wake. This results suggests some possible improvements in the numerical models currently used for CFD of cavitating flows. Professor at Arts et Metiers ParisTech, Director of the LML laboratory.

  7. Dynamics and noise emission of laser induced cavitation bubbles in a vortical flow field

    Science.gov (United States)

    Oweis, Ghanem F.; Choi, Jaehyug; Ceccio, Steven L.

    2004-03-01

    The sound produced by the collapse of discrete cavitation bubbles was examined. Laser-generated cavitation bubbles were produced in both a quiescent and a vortical flow. The sound produced by the collapse of the cavitation bubbles was recorded, and its spectral content was determined. It was found that the risetime of the sound pulse produced by the collapse of single, spherical cavitation bubbles in quiescent fluid exceeded that of the slew rate of the hydrophone, which is consistent with previously published results. It was found that, as collapsing bubbles were deformed by the vortical flow, the acoustic impulse of the bubbles was reduced. Collapsing nonspherical bubbles often created a sound pulse with a risetime that exceeded that of the hydrophone slew rate, although the acoustic impulse created by the bubbles was influenced largely by the degree to which the bubbles became nonspherical before collapse. The noise produced by the slow growth of cavitation bubbles in the vortex core was not detectable. These results have implications for the interpretation of hydrodynamic cavitation noise produced by vortex cavitation.

  8. Intensification of esterification of non edible oil as sustainable feedstock using cavitational reactors.

    Science.gov (United States)

    Mohod, Ashish V; Subudhi, Abhijeet S; Gogate, Parag R

    2017-05-01

    Using sustainable feed stock such as non-edible oil for the biodiesel production can be one of the cost effective approaches considering the ever growing interest towards renewable energy and problems in existing approaches for production. However, due to the high free fatty acid content, non-edible oils require considerable preprocessing before the actual transesterification reaction for biodiesel production. The present work focuses on intensification of the esterification reaction used as preprocessing step based on acoustic and hydrodynamic cavitation also presenting the comparison with the conventional approach. Karanja oil with initial acid value as 14.15mg of KOH/g of oil has been used as a sustainable feedstock. Effect of operating parameters such as molar ratio, catalyst loading, temperature and type of catalyst (sulfuric acid and Amberlyst-15) on the acid value reduction has been investigated. The maximum reduction in the acid value (final acid value as 2.7mg of KOH/g of oil) was obtained using acoustic cavitation at optimum molar ratio of oil to methanol as 1:5 and 2% sulfuric acid loading at ambient temperature. In the case of hydrodynamic cavitation, acid value reduced upto 4.2mg of KOH under optimized conditions of first stage processing. In the second stage esterification using hydrodynamic cavitation and conventional approach, the final acid value was 3.6 and 3.8mg of KOH/g of oil respectively. Energy requirement analysis for ultrasound and conventional approaches clearly established the superiority of the ultrasound based approach. The present study clearly demonstrated that significant intensification benefits can be obtained in terms of the reduction in the molar ratio and operating temperature for the case of acoustic cavitation as compared to the conventional approach with somewhat lower effects for the hydrodynamic cavitation. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. The use of hydrodynamic disintegration as a means to improve anaerobic digestion of activated sludge

    OpenAIRE

    Machnicka, A; Grűbel, K; Suschka, J

    2009-01-01

    Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. By applying hydrodynamic disintegration the lysis of cells occurs in minutes instead of days. The intracellular and extracellular components are set free and are immediately available for biological degradation which leads to an improvement of the subsequent anaerobic process. Hydrodynamic disintegration of the activated sludge results in organic matter and a polymer transfer ...

  10. Extending cavitation models to subcooled and superheated nozzle flow

    International Nuclear Information System (INIS)

    Schmidt, D.P.; Corradini, M.L.

    1997-01-01

    Existing models for cavitating flow are extended to apply to discharge of hot liquid through nozzles. Two types of models are considered: an analytical model and a two-dimensional numerical model. The analytical model of cavitating nozzle flow is reviewed and shown to apply to critical nozzle flow where the liquid is subcooled with respect to the downstream conditions. In this model the liquid and vapor are assumed to be in thermodynamic equilibrium. The success of this analytical model suggests that hydrodynamic effects dominate the subcooled nozzle flow. For more detailed predictions an existing multi-dimensional cavitation model based on hydrodynamic non-equilibrium is modified to apply to discharge of hot liquid. Non-equilibrium rate data from experimental measurements are used to close the equations. The governing equations are solved numerically in time and in two spatial dimensions on a boundary fitted grid. Results are shown for flow through sharp nozzles, and the coefficient of discharge is found to agree with experimental measurements for both subcooled and flashing fluid. (author)

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

    Science.gov (United States)

    Mahdi, M.; Ebrahimi, R.; Shams, M.

    2011-06-01

    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.

  12. Cavitation instabilities in hydraulic machines

    International Nuclear Information System (INIS)

    Tsujimoto, Y

    2013-01-01

    Cavitation instabilities in hydraulic machines, hydro turbines and turbopump inducers, are reviewed focusing on the cause of instabilities. One-dimensional model of hydro turbine system shows that the overload surge is caused by the diffuser effect of the draft tube. Experiments show that this effect also causes the surge mode oscillations at part load. One dimensional model of a cavitating turbopump inducer shows that the mass flow gain factor, representing the cavity volume increase caused by the incidence angle increase is the cause of cavitation surge and rotating cavitation. Two dimensional model of a cavitating turbopump inducer shows that various modes of cavitation instabilities start to occur when the cavity length becomes about 65% of the blade spacing. This is caused by the interaction of the local flow near the cavity trailing edge with the leading edge of the next blade. It was shown by a 3D CFD that this is true also for real cases with tip cavitation. In all cases, it was shown that cavitation instabilities are caused by the fundamental characteristics of cavities that the cavity volume increases with the decrease of ambient pressure or the increase of the incidence angle

  13. 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...

  14. An optimised set-up for total reflection particle induced X-ray emission

    International Nuclear Information System (INIS)

    Kan, J.A. van; Vis, R.D.

    1997-01-01

    MeV proton beams at small angles of incidence (0-35 mrad) are used to analyse trace elements on flat surfaces such as Si wafers or quartz substrates. In these experiments, the particle induced X-ray emission (PIXE) signal is used in a new optimized set-up. This set-up is constructed in such a way that the X-ray detector can reach very large solid angles, larger than 1 sr. Use of these large detector solid angles, combined with the reduction of bremsstrahlung background, affords limits of detection (LOD) of the order of 10 10 at cm -2 using total reflection particle induced X-ray emission (TPIXE). The LODs from earlier TPIXE measurements in a non-optimized set-up are used to estimate LODs in the new TPIXE set-up. Si wafers with low surface concentrations of V, Ni, Cu and Ag are used as standards to calibrate the LODs found with this set-up. The metal concentrations are determined by total reflection X-ray fluorescence (TXRF). The TPIXE measurements are compared with TXRF measurements on the same wafers. (Author)

  15. Mathematical model of the electronuclear set-up on the beam of the JINR synchrotron

    International Nuclear Information System (INIS)

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

    2003-01-01

    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

  16. Trace element analysis in an optimized set-up for total reflection PIXE (TPIXE)

    International Nuclear Information System (INIS)

    Van Kan, J.A.; Vis, R.D.

    1996-01-01

    A newly constructed chamber for measuring with MeV proton beams at small incidence angles (0 to 35 mrad) is used to analyse trace elements on flat surfaces such as Si wafers, quartz substrates and perspex. This set-up is constructed in such a way that the X-ray detector can reach very large solid angles, larger than 1 sr. Using these large solid angles in combination with the reduction of bremsstrahlungs background, lower limits of detection (LOD) using TPIXE can be obtained as compared with PIXE in the conventional geometry. Standard solutions are used to determine the LODs obtainable with TPIXE in the optimized set-up. These solutions contain traces of As and Sr with concentrations down to 20 ppb in an insulin solution. The limits of detection found are compared with earlier ones obtained with TPIXE in a non optimized set-up and with TXRF results. (author)

  17. 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.

  18. Implementation of random set-up errors in Monte Carlo calculated dynamic IMRT treatment plans

    International Nuclear Information System (INIS)

    Stapleton, S; Zavgorodni, S; Popescu, I A; Beckham, W A

    2005-01-01

    The fluence-convolution method for incorporating random set-up errors (RSE) into the Monte Carlo treatment planning dose calculations was previously proposed by Beckham et al, and it was validated for open field radiotherapy treatments. This study confirms the applicability of the fluence-convolution method for dynamic intensity modulated radiotherapy (IMRT) dose calculations and evaluates the impact of set-up uncertainties on a clinical IMRT dose distribution. BEAMnrc and DOSXYZnrc codes were used for Monte Carlo calculations. A sliding window IMRT delivery was simulated using a dynamic multi-leaf collimator (DMLC) transport model developed by Keall et al. The dose distributions were benchmarked for dynamic IMRT fields using extended dose range (EDR) film, accumulating the dose from 16 subsequent fractions shifted randomly. Agreement of calculated and measured relative dose values was well within statistical uncertainty. A clinical seven field sliding window IMRT head and neck treatment was then simulated and the effects of random set-up errors (standard deviation of 2 mm) were evaluated. The dose-volume histograms calculated in the PTV with and without corrections for RSE showed only small differences indicating a reduction of the volume of high dose region due to set-up errors. As well, it showed that adequate coverage of the PTV was maintained when RSE was incorporated. Slice-by-slice comparison of the dose distributions revealed differences of up to 5.6%. The incorporation of set-up errors altered the position of the hot spot in the plan. This work demonstrated validity of implementation of the fluence-convolution method to dynamic IMRT Monte Carlo dose calculations. It also showed that accounting for the set-up errors could be essential for correct identification of the value and position of the hot spot

  19. Implementation of random set-up errors in Monte Carlo calculated dynamic IMRT treatment plans

    Science.gov (United States)

    Stapleton, S.; Zavgorodni, S.; Popescu, I. A.; Beckham, W. A.

    2005-02-01

    The fluence-convolution method for incorporating random set-up errors (RSE) into the Monte Carlo treatment planning dose calculations was previously proposed by Beckham et al, and it was validated for open field radiotherapy treatments. This study confirms the applicability of the fluence-convolution method for dynamic intensity modulated radiotherapy (IMRT) dose calculations and evaluates the impact of set-up uncertainties on a clinical IMRT dose distribution. BEAMnrc and DOSXYZnrc codes were used for Monte Carlo calculations. A sliding window IMRT delivery was simulated using a dynamic multi-leaf collimator (DMLC) transport model developed by Keall et al. The dose distributions were benchmarked for dynamic IMRT fields using extended dose range (EDR) film, accumulating the dose from 16 subsequent fractions shifted randomly. Agreement of calculated and measured relative dose values was well within statistical uncertainty. A clinical seven field sliding window IMRT head and neck treatment was then simulated and the effects of random set-up errors (standard deviation of 2 mm) were evaluated. The dose-volume histograms calculated in the PTV with and without corrections for RSE showed only small differences indicating a reduction of the volume of high dose region due to set-up errors. As well, it showed that adequate coverage of the PTV was maintained when RSE was incorporated. Slice-by-slice comparison of the dose distributions revealed differences of up to 5.6%. The incorporation of set-up errors altered the position of the hot spot in the plan. This work demonstrated validity of implementation of the fluence-convolution method to dynamic IMRT Monte Carlo dose calculations. It also showed that accounting for the set-up errors could be essential for correct identification of the value and position of the hot spot.

  20. 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.

  1. Hydrodynamic Lubrication

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 9. Hydrodynamic Lubrication Experiment with 'Floating' Drops. Jaywant H Arakeri K R Sreenivas. General Article Volume 1 Issue 9 September 1996 pp 51-58. Fulltext. Click here to view fulltext PDF. Permanent link:

  2. 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.

  3. Hydrodynamic disperser

    Energy Technology Data Exchange (ETDEWEB)

    Bulatov, A.I.; Chernov, V.S.; Prokopov, L.I.; Proselkov, Yu.M.; Tikhonov, Yu.P.

    1980-01-15

    A hydrodynamic disperser is suggested which contains a housing, slit nozzles installed on a circular base arranged opposite from each other, resonators secured opposite the nozzle and outlet sleeve. In order to improve the effectiveness of dispersion by throttling the flow, each resonator is made in the form of a crimped plate with crimpings that decrease in height in a direction towards the nozzle.

  4. Special set-up and treatment techniques for the radiotherapy of pediatric malignancies

    International Nuclear Information System (INIS)

    Martinez, A.; Donaldson, S.S.; Bagshaw, M.A.

    1977-01-01

    The prevention of serious and long term complications of treatment have become as important a consideration in the therapy of children with malignant disease as the goal of tumor control. This balance requires meticulous treatment planning and attention to the treatment preparation and immobilization techniques when radiotherapy is administered to children. Accurate localization of tumor volume and daily reproducibility is essential for delivering precise irradiation. Four special set-up and treatment techniques which have a specific usefulness in radiotherapy for pediatric malignancies are defined and illustrated with the aid of clinical cases. They include the three point set-up, the split beam technique, the isocentric technique, and the strinking field technique

  5. Cavitational boiling of liquids

    International Nuclear Information System (INIS)

    Kostyuk, V.V.; Berlin, I.I.; Borisov, N.N.; Karpyshev, A.V.

    1986-01-01

    Transition boiling is a term usually denoting the segment of boiling curve 1-2, where the heat flux, q, decreases as the temperature head, ΔT/sub w/=T/sub w/-T/sub s/, increases. Transition boiling is the subject of numerous papers. Whereas most researchers have studied transition boiling of saturated liquids the authors studied for many years transition boiling of liquids subcooled to the saturation temperature. At high values of subcooling, ΔT/sub sub/=T/sub s/-T/sub 1/, an anomalous dependence of the heat flux density on the temperature head was detected. Unlike a conventional boiling curve, where a single heat flux maximum occurs, another maximum is seen in the transition boiling segment, the boiling being accompanied by strong noise. The authors refer to this kind of boiling as cavitational. This process is largely similar to noisy boiling of helium-II. This article reports experimental findings for cavitational boiling of water, ethanol, freon-113 and noisy boiling of helium-II

  6. An experimental set-up for carbon isotopic analysis of atmospheric ...

    Indian Academy of Sciences (India)

    We present here, an experimental set-up developed for the first time in India for the ... The internal reproducibility (precision) for the δ13C ... interaction of CO2 and water, and reproduce iso- ..... enhanced emission of anthropogenic CO2, varia-.

  7. Setting up Schizosaccharomyces pombe crosses/matings

    DEFF Research Database (Denmark)

    Ekwall, Karl; Thon, Genevieve

    2017-01-01

    Here we provide methods for setting up standard crosses with Schizosaccharomyces pombe strains. All strain genotypes and pedigrees should be recorded in a laboratory strain book. Matings between two haploid strains of interest are induced on solid medium poor in nitrogen. Usually, sporulation agar...

  8. A method for patient set-up guidance in radiotherapy using augmented reality

    International Nuclear Information System (INIS)

    Talbot, J.; Meyer, J.; Watts, R.; Grasset, R.

    2009-01-01

    Full text: A system for patient set-up in external beam radiotherapy was developed using Augmented Reality (AR). Live images of the linac treatment couch and patient were obtained with video cameras and displayed on a nearby monitor. A 3D model of the patient's external contour was obtained from planning CT data, and AR tracking software was used to superimpose the model onto the video images in the correct position for treatment. Throughout set-up and treatment, the user can view the monitor and visually confirm that the patient is positioned correctly. To ensure that the virtual contour was displayed in the correct position, a process was devised to register the coordinates of the linac with the camera images. A cube with AR tracking markers attached to its faces was constructed for alignment with the isocentre using room lasers or cone-beam CT. The performance of the system was investigated in a clinical environment by using it to position an anthropomorphic phantom without the aid of additional set-up methods. The positioning errors were determined by means of CBCT and image registration. The translational set-up errors were found to be less than 2.4 mm and the rotational errors less than 0.3 0 . This proof-of-principle study has demonstrated the feasibility of using AR for patient position and pose guidance.

  9. The possibility to use 'energy plus transmutation' set-up for neutron ...

    Indian Academy of Sciences (India)

    Neutron field was measured in different places of this set- up using different .... to see that the proton integral was around 1013 protons for all experiments. The shape of the .... The lines are drawn to guide the eyes, only statistical errors are ...

  10. Technologies for the Fast Set-Up of Automated Assembly Processes

    DEFF Research Database (Denmark)

    Krüger, Norbert; Ude, Ales; Petersen, Henrik Gordon

    2014-01-01

    of so called few-of-a-kind production. Therefore, most production of this kind is done manually and thus often performed in low-wage countries. In the IntellAct project, we have developed a set of methods which facilitate the set-up of a complex automatic assembly process, and here we present our work...

  11. 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

  12. 12 November 1991-Ministerial Order setting up a Commission for assessing information in the nuclear field

    International Nuclear Information System (INIS)

    1991-01-01

    The Commission sets up by this Order must ensure that the public is kept informed on the technical, health, ecological, economic and financial aspects of nuclear energy, and advises the Secretary of State for Energy on the conditions for informing the public and proposes methods for disseminating such information. (NEA)

  13. The Use of Instructional and Motivational Self-Talk in Setting up a Physical Education Lesson

    Science.gov (United States)

    Zourbanos, Nikos

    2013-01-01

    The main purpose of this article is to provide guidelines to physical educators for setting up a self-talk program during their lesson. The article briefly presents definitions of self-talk and research findings in sport and physical education to highlight the important benefits of positive self-talk in enhancing task performance. It also provides…

  14. Automotive RF immunity test set-up analysis : why test results can't compare

    NARCIS (Netherlands)

    Coenen, Mart; Pues, H.; Bousquet, T.

    2011-01-01

    Though the automotive RF emission and RF immunity requirements are highly justifiable, the application of those requirements in an non-intended manner leads to false conclusions and unnecessary redesigns for the electronics involved. When the test results become too dependent upon the test set-up

  15. The pattern of trauma in private general medical practice set-up Port ...

    African Journals Online (AJOL)

    BACKGROUND: Private general medical practice establishments appear to be treating a significant number of trauma cases including more serious ones. Aim: To find out the extent of such treatment of trauma and what has made this possible. METHODS: All trauma cases treated in a private general medical practice set up ...

  16. 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.

  17. Setting up a randomized clinical trial in the UK: approvals and process.

    Science.gov (United States)

    Greene, Louise Eleanor; Bearn, David R

    2013-06-01

    Randomized clinical trials are considered the 'gold standard' in primary research for healthcare interventions. However, they can be expensive and time-consuming to set up and require many approvals to be in place before they can begin. This paper outlines how to determine what approvals are required for a trial, the background of each approval and the process for obtaining them.

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

    DEFF Research Database (Denmark)

    Erik Weinell, Claus; 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...

  19. Setting up a child eye care centre: the Mercy Eye Hospital, Abak ...

    African Journals Online (AJOL)

    Aim: To document and share our experience in setting up a Child Eye Care Centre within a rural mission eye hospital and document subsequent development of services. Method: The location of the project was Mercy Eye Hospital (MEH) Abak, Akwa Ibom State in the South South zone of Nigeria). Consent to commence ...

  20. Order of 27 February 1985 setting up a Nuclear Engineering Terminology Commission

    International Nuclear Information System (INIS)

    1985-01-01

    The Commission set up by this Order will draw up an inventory of the gaps in French nuclear engineering vocabulary, taking into account users' needs; it will also propose and revise the necessary terms in the light of present knowledge and contribute to collection and harmonisation of terminological and neological data. (NEA) [fr

  1. 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…

  2. Rank the Voltage across Light Bulbs … Then Set up the Live Experiment

    Science.gov (United States)

    Jacobs, Greg C.

    2018-01-01

    The Tasks Inspired by Physics Education Research (TIPERS) workbooks pose questions in styles quite different from the end-of-chapter problems that those of us of a certain age were assigned back in the days before Netscape. My own spin on TIPERS is not just to do them on paper, but to have students set up the situations in the laboratory to…

  3. 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...

  4. Nucleation and cavitation in parahydrogen

    International Nuclear Information System (INIS)

    Pi, Martí; Barranco, Manuel; Navarro, Jesús; Ancilotto, Francesco

    2012-01-01

    Highlights: ► We have constructed a density functional (DF) for parahydrogen between 14 and 32 K. ► The experimental equation of state and the surface tension are well reproduced. ► We have investigated nucleation and cavitations processes in the metastable phase. ► We have obtained the electron bubble explosion within the capillary model. - Abstract: We have used a density functional approach to investigate thermal homogeneous nucleation and cavitation in parahydrogen. The effect of electrons as seeds of heterogeneous cavitation in liquid parahydrogen is also discussed within the capillary model.

  5. Susceptibility of CANDU steam generator preheater to cavitation erosion

    International Nuclear Information System (INIS)

    Laroche, S.L.; Sun, L.; Pietralik, J.M.

    2012-01-01

    In 2009, Darlington Steam Generator (SG) tube inspections revealed some tubes had degraded in the preheater. The tube degradation occurred at the clearance gap between the tube and the preheater baffle and reached up to 50% through-wall depth at the baffles in the middle portion of the preheater. The general pattern of the damage and the elemental composition analysis suggested that the degradation was the result of a hydrodynamic process, such as cavitation erosion. Cavitation erosion occurs when vapour bubbles exist or form in the flowing liquid and then these bubbles collapse violently in the vicinity of the wall. These bubbles collapse when steam bubbles contact water that is sufficiently subcooled, below the saturation temperature. In the gap between the tube and the preheater baffle, low flow will exist due to the pressure difference across the baffle plate. In addition, heat transfer occurs from the primary-side fluid to the secondary-side fluid within this clearance gap that is driven by the primary-to-secondary temperature difference. Factors, such as the tube position in the baffle hole and fouling, influence the local conditions and can cause subcooled boiling that result in cavitation. This paper presents a study of flow and heat transfer phenomena to determine the factors contributing to cavitation erosion in SG preheaters. The analysis used the THIRST1 code for a 3-dimensional thermalhydraulic simulation of the steam generators and the ANSYS FLUENT®2 code for detailed calculations of flow and heat transfer in the clearance gaps. This study identifies that tubes in the preheater region are susceptible to cavitation erosion and indicates that this area should be part of the station inspection program because, regardless of preheater design, some tubes may experience the thermalhydraulic conditions and undergo degradations similar to those observed for the tubes in Darlington SGs. (author)

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

    International Nuclear Information System (INIS)

    D'Agostino, L

    2013-01-01

    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

  7. Cavitation nuclei measurements - A review

    International Nuclear Information System (INIS)

    Billet, M.L.

    1985-01-01

    The measurement of cavitation nuclei has been the goal of many cavitation research laboratories and has resulted in the development of many methods. Two significantly different approaches have been developed. One is to measure the particulate-microbubble distribution by utilizing acoustical, electrical or optical methods. The other approach measures a liquid tension and a rate of cavitation events for a liquid in order to establish a cavitation susceptibility. Comparisons between various methods indicate that most methods are capable of giving an indication of the nuclei distribution. Measurements obtained in the ocean environment indicate an average of three bubbles per cubic centimeter are present; whereas, water tunnel bubble distributions vary from much less than one to over a hundred per cubic centimeter

  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. A simple and convenient set-up for high-temperature Brillouin light scattering

    International Nuclear Information System (INIS)

    Guerette, Michael; Huang Liping

    2012-01-01

    An emulated platelet geometry (or reflection-induced platelet geometry) is employed to collect photons scattered from both longitudinal and transverse acoustic waves travelling within a bulk transparent sample sitting on a reflective Pt plate. Temperature of the sample was controlled with a Linkam TS1500 optical furnace (maximum temperature of 1500 °C). This simple and convenient set-up allows a full determination of elastic constants of transparent materials in situ as a function of temperature from Brillouin light scattering. Structural information can be gained at the same time by guiding the scattered light into a Raman spectrometer using a flipping mirror or a beam splitter. We will demonstrate the applications of this set-up in transparent inorganic glasses, but it can be easily extended to any other transparent materials, either crystalline or amorphous in nature. (paper)

  10. 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

    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...... 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...

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

    Science.gov (United States)

    Olesen, C G; Larsen, B H; Andresen, E L; de Zee, M

    2015-01-01

    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 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 performance.

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

    Science.gov (United States)

    Suri, Ashish; Roy, Tara Sankar; Lalwani, Sanjeev; Deo, Rama Chandra; Tripathi, Manjul; Dhingra, Renu; Bhardwaj, Daya Nand; Sharma, Bhawani Shankar

    2014-01-01

    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.

  13. Act No. 15 of 22 April 1980 setting up the Nuclear Safety Council

    International Nuclear Information System (INIS)

    1980-01-01

    The Spanish authorities are in the process or reorganising the public nuclear sector in order to separate the promotional and research aspects of the uses of nuclear energy for peaceful purposes from the regulation and control of such activities. To this effect this Act sets up a Nuclear Safety Council which takes over part of the duties and the personnel of the Junta de Energia Nuclear provided for by the Act of 29th April 1964 on Nuclear Energy. The new Nuclear Safety Council is a body which is independent of the State central administration and has legal personality as well as its own financial resources required to carry out its duties. The latter comprise, inter alia, proposing to the Government the regulations required in matters of nuclear safety and radiation protection; this includes the setting-up of standards and criteria for the selection of nuclear installation sites, in consultation with the local competent bodies. (NEA) [fr

  14. 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.

  15. X-ray fluorescence (XRF) set-up with a low power X-ray tube

    International Nuclear Information System (INIS)

    Gupta, Sheenu; Deep, Kanan; Jain, Lalita; Ansari, M.A.; Mittal, Vijay Kumar; Mittal, Raj

    2010-01-01

    The X-ray fluorescence set-up with a 100 W X-ray tube comprises a computer controlled system developed for remote operation and monitoring of tube and an adjustable stable 3D arrangement to procure variable excitation energies with low scattered background. The system was tested at different filament currents/anode voltages. The MDL of the set-up at 0.05-1.00 mA/4-12 kV is found ∼(1-100) ppm for K and L excitations and ∼(200-700) ppm for M excitations of elements and improves with filament current and anode voltage. Moreover, L measurements for Sm and Eu at five K X-ray energies of elements(Z=29-40) and analytical determination in some synthetic samples were undertaken.

  16. 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, 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.

  17. Stereo particle image velocimetry set up for measurements in the wake of scaled wind turbines

    Science.gov (United States)

    Campanardi, Gabriele; Grassi, Donato; Zanotti, Alex; Nanos, Emmanouil M.; Campagnolo, Filippo; Croce, Alessandro; Bottasso, Carlo L.

    2017-08-01

    Stereo particle image velocimetry measurements were carried out in the boundary layer test section of Politecnico di Milano large wind tunnel to survey the wake of a scaled wind turbine model designed and developed by Technische Universität München. The stereo PIV instrumentation was set up to survey the three velocity components on cross-flow planes at different longitudinal locations. The area of investigation covered the entire extent of the wind turbines wake that was scanned by the use of two separate traversing systems for both the laser and the cameras. Such instrumentation set up enabled to gain rapidly high quality results suitable to characterise the behaviour of the flow field in the wake of the scaled wind turbine. This would be very useful for the evaluation of the performance of wind farm control methodologies based on wake redirection and for the validation of CFD tools.

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

    OpenAIRE

    POPESCU, A.; RADOI, C.

    2003-01-01

    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 w...

  19. 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....

  20. Set up of a method for the adjustment of resonance parameters on integral experiments

    International Nuclear Information System (INIS)

    Blaise, P.

    1996-01-01

    Resonance parameters for actinides play a significant role in the neutronic characteristics of all reactor types. All the major integral parameters strongly depend on the nuclear data of the isotopes in the resonance-energy regions.The author sets up a method for the adjustment of resonance parameters taking into account the self-shielding effects and restricting the cross section deconvolution problem to a limited energy region. (N.T.)

  1. Extracranial stereotactic radiation therapy: set-up accuracy of patients treated for liver metastases

    International Nuclear Information System (INIS)

    Herfarth, K.K.; Debus, J.; Lohr, F.; Bahner, M.L.; Fritz, P.; Hoess, A.; Schlegel, W. Ph.D.; Wannenmacher, M.F.

    2000-01-01

    Purpose: Patients with liver metastases might benefit from high-dose conformal radiation therapy. A high accuracy of repositioning and a reduction of target movement are necessary for such an approach. The set-up accuracy of patients with liver metastases treated with stereotactic single dose radiation was evaluated. Methods and Materials: Twenty-four patients with liver metastases were treated with single dose radiation therapy on 26 occasions using a self-developed stereotactic frame. Liver movement was reduced by abdominal pressure. The effectiveness was evaluated under fluoroscopy. CT scans were performed on the planning day and directly before treatment. Representative reference marks were chosen and the coordinates were calculated. In addition, the target displacement was quantitatively evaluated after treatment. Results: Diaphragmal movement was reduced to median 7 mm (range: 3-13 mm). The final set-up accuracy of the body was limited to all of median 1.8 mm in latero-lateral direction (range: 0.3-5.0 mm) and 2.0 mm in anterior-posterior direction (0.8-3.8 mm). Deviations of the body in cranio-caudal direction were always less than the thickness of one CT slice (<5 mm). However, a repositioning was necessary in 16 occasions. The final target shift was median 1.6 mm (0.2-7.0 mm) in latero-lateral and 2.3 mm in anterior-posterior direction (0.0-6.3 mm). The median shift in cranio-caudal direction was 4.4 mm (0.0-10.0 mm). Conclusions: In patients with liver metastases, a high set-up accuracy of the body and the target can be achieved. This allows a high-dose focal radiotherapy of these lesions. However, a control CT scan should be performed directly before therapy to confirm set-up accuracy and possibly prompt necessary corrections

  2. Coincidence set-up with a high duty-cycle, high energy electron accelerator

    International Nuclear Information System (INIS)

    Leconte, P.

    1981-01-01

    Important studies are now undertaken to develop continuous wave electron accelerators with energy ranging from 1 to 4 Gev. So very important effort must be now put on the development of the experimental set-up matching the performances expected from the electron beam. Major steps in the understanding of the nuclear systems will come from more and more exclusive experiments where well defined mechanisms will be selected

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

    CERN Multimedia

    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...

  4. Over-relaxation phenomena during the set-up of RFP plasmas

    International Nuclear Information System (INIS)

    Nordlund, P.; Mazur, S.

    1995-03-01

    Experiments on the Extrap T1 reversed field pinch have shown that the formation of the RFP configuration is quite sensitive to the relative programming of the toroidal field and ohmic heating circuits. In this paper, new measurements of the evolution of the current density profile and of the spectral structure of the fluctuations during the set-up phase of RFP plasmas in the T1 experiment are presented. These measurements improve the understanding of the role of different spectral components in the dynamics of RFP formation. Under unfavourable (slow) set-up conditions, comparatively high energy is accumulated in m = 1 internal kinks prior to reversal of the edge toroidal fields. At reversal, nonlinearly driven m = 0 modes trigger a rapid broadening of the m = 1 spectrum. This behaviour is associated with a violent suppression of the current density in the core leading to an over-relaxation of the discharge involving a hollowing of the parallel current density profile. The over-relaxation phenomenon increases the volt-second consumption and plasma/wall interaction during RFP set-up, and degrades the flat-top discharge performance. 15 refs, 5 figs, 1 tab

  5. Over-relaxation phenomena during the set-up of RFP plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Nordlund, P.; Mazur, S.

    1995-03-01

    Experiments on the Extrap T1 reversed field pinch have shown that the formation of the RFP configuration is quite sensitive to the relative programming of the toroidal field and ohmic heating circuits. In this paper, new measurements of the evolution of the current density profile and of the spectral structure of the fluctuations during the set-up phase of RFP plasmas in the T1 experiment are presented. These measurements improve the understanding of the role of different spectral components in the dynamics of RFP formation. Under unfavourable (slow) set-up conditions, comparatively high energy is accumulated in m = 1 internal kinks prior to reversal of the edge toroidal fields. At reversal, nonlinearly driven m = 0 modes trigger a rapid broadening of the m = 1 spectrum. This behaviour is associated with a violent suppression of the current density in the core leading to an over-relaxation of the discharge involving a hollowing of the parallel current density profile. The over-relaxation phenomenon increases the volt-second consumption and plasma/wall interaction during RFP set-up, and degrades the flat-top discharge performance. 15 refs, 5 figs, 1 tab.

  6. Single ion hit detection set-up for the Zagreb ion microprobe

    Science.gov (United States)

    Smith, R. W.; Karlušić, M.; Jakšić, M.

    2012-04-01

    Irradiation of materials by heavy ions accelerated in MV tandem accelerators may lead to the production of latent ion tracks in many insulators and semiconductors. If irradiation is performed in a high resolution microprobe facility, ion tracks can be ordered by submicrometer positioning precision. However, full control of the ion track positioning can only be achieved by a reliable ion hit detection system that should provide a trigger signal irrespectively of the type and thickness of the material being irradiated. The most useful process that can be utilised for this purpose is emission of secondary electrons from the sample surface that follows the ion impact. The status report of the set-up presented here is based on the use of a channel electron multiplier (CEM) detector mounted on an interchangable sample holder that is inserted into the chamber in a close geometry along with the sample to be irradiated. The set-up has been tested at the Zagreb ion microprobe for different ions and energies, as well as different geometrical arrangements. For energies of heavy ions below 1 MeV/amu, results show that efficient (100%) control of ion impact can be achieved only for ions heavier than silicon. The successful use of the set-up is demonstrated by production of ordered single ion tracks in a polycarbonate film and by monitoring fluence during ion microbeam patterning of Foturan glass.

  7. Using a Robust Design Approach to Optimize Chair Set-up in Wheelchair Sport

    Directory of Open Access Journals (Sweden)

    David S. Haydon

    2018-02-01

    Full Text Available Optimisation of wheelchairs for court sports is currently a difficult and time-consuming process due to the broad range of impairments across athletes, difficulties in monitoring on-court performance, and the trade-off set-up that parameters have on key performance variables. A robust design approach to this problem can potentially reduce the amount of testing required, and therefore allow for individual on-court assessments. This study used orthogonal design with four set-up factors (seat height, depth, and angle, as well as tyre pressure at three levels (current, decreased, and increased for three elite wheelchair rugby players. Each player performed two maximal effort sprints from a stationary position in nine different set-ups, with this allowing for detailed analysis of each factor and level. Whilst statistical significance is difficult to obtain due to the small sample size, meaningful difference results aligning with previous research findings were identified and provide support for the use of this approach.

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

    International Nuclear Information System (INIS)

    Glotin, F.; Jaroszynski, D.; Marcouille, O.

    1995-01-01

    Previous spectral and laser pulse length measurements carried out on the CLIO FEL at wavelength λ=8.5 μm 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 Nλ. 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 μm have already been performed to validate the technic, leading to results similar to those obtained with our previous Michelson set-up

  9. Development of high pressure rinsing set up for 650 MHz, 5- cell superconducting RF cavity cleaning

    International Nuclear Information System (INIS)

    Suhane, S.K.; Chauhan, S.K.; Bose, A.; Kokil, S.V.; Rajput, D.S.; Oraon, B.; Md Hussain; Sahu, A.; Raghavendra, S.; Joshi, S.C.

    2015-01-01

    High pressure rinsing (HPR) is an ultra-cleanliness process for the surface preparation of high field superconducting RF cavities. Any dust particle or chemical residue on the interior of cavity causes field emission. Jets of high pressure (80-100 bar) ultra pure water dislodge surface contaminants that normally resist removal with conventional rinsing procedures, leading to substantial reduction in field emission and better cavity performance. For cleaning of 650 MHz, 5-cell SRF cavities, a high pressure rinsing set up has been developed at RRCAT. The HPR tool has a rotating wand coaxial with the vertically mounted SRF cavity that is moving up and down. Fan style spray nozzles are attached to the end of the rotating wand and the water jets emerging from spray nozzles scan the entire internal surface of the cavity. The set-up was installed in a specially built clean area meeting cleanliness class 100 standards. The ultrapure water with resistivity 2 ≥ 18 MΩ-cm required for rinsing is obtained from a dedicated water purification system installed for this purpose. The paper describes the salient design and constructional details of the high pressure rinsing set up. Characterization of water jet parameters based on the momentum transfer between the water jet and a load cell is also presented. (author)

  10. 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.

  11. 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)

  12. Forces and moments on a slender, cavitating body

    Energy Technology Data Exchange (ETDEWEB)

    Hailey, C.E.; Clark, E.L.; Buffington, R.J.

    1988-01-01

    Recently a numerical code has been developed at Sandia National Laboratories to predict the pitching moment, normal force, and axial force of a slender, supercavitating shape. The potential flow about the body and cavity is calculated using an axial distribution of source/sink elements. The cavity surface is assumed to be a constant pressure streamline, extending beyond the base of the model. Slender body approximation is used to model the crossflow for small angles of attack. A significant extension of previous work in cavitation flow is the inclusion of laminar and turbulent boundary layer solutions on the body. Predictions with this code, for axial force at zero angle of attack, show good agreement with experiments. There are virtually no published data availble with which to benchmark the pitching moment and normal force predictions. An experiment was designed to measure forces and moments on a supercavitation shape. The primary reason for the test was to obtain much needed data to benchmark the hydrodynamic force and moment predictions. Since the numerical prediction is for super cavitating shapes at very small cavitation numbers, the experiment was designed to be a ventilated cavity test. This paper describes the experimental procedure used to measure the pitching moment, axial and normal forces, and base pressure on a slender body with a ventilated cavity. Limited results are presented for pitching moment and normal force. 5 refs., 7 figs.

  13. Numerical and experimental investigations on cavitation erosion

    Science.gov (United States)

    Fortes Patella, R.; Archer, A.; Flageul, C.

    2012-11-01

    A method is proposed to predict cavitation damage from cavitating flow simulations. For this purpose, a numerical process coupling cavitating flow simulations and erosion models was developed and applied to a two-dimensional (2D) hydrofoil tested at TUD (Darmstadt University of Technology, Germany) [1] and to a NACA 65012 tested at LMH-EPFL (Lausanne Polytechnic School) [2]. Cavitation erosion tests (pitting tests) were carried out and a 3D laser profilometry was used to analyze surfaces damaged by cavitation [3]. The method allows evaluating the pit characteristics, and mainly the volume damage rates. The paper describes the developed erosion model, the technique of cavitation damage measurement and presents some comparisons between experimental results and numerical damage predictions. The extent of cavitation erosion was correctly estimated in both hydrofoil geometries. The simulated qualitative influence of flow velocity, sigma value and gas content on cavitation damage agreed well with experimental observations.

  14. A Ffowcs Williams and Hawkings formulation for hydroacoustic analysis of propeller sheet cavitation

    Science.gov (United States)

    Testa, C.; Ianniello, S.; Salvatore, F.

    2018-01-01

    A novel hydroacoustic formulation for the prediction of tonal noise emitted by marine propellers in presence of unsteady sheet cavitation, is presented. The approach is based on the standard Ffowcs Williams and Hawkings equation and the use of transpiration (velocity and acceleration) terms, accounting for the time evolution of the vapour cavity attached on the blade surface. Drawbacks and potentialities of the method are tested on a marine propeller operating in a nonhomogeneous onset flow, by exploiting the hydrodynamic data from a potential-based panel method equipped with a sheet cavitation model and comparing the noise predictions with those carried out by an alternative numerical approach, documented in literature. It is shown that the proposed formulation yields a one-to-one correlation between emitted noise and sheet cavitation dynamics, carrying out accurate predictions in terms of noise magnitude and directivity.

  15. Review of parameters influencing the structural response of a submerged body under cavitation conditions

    International Nuclear Information System (INIS)

    Escaler, X; De La Torre, O; Farhat, M

    2015-01-01

    Submerged structures that operate under extreme flows are prone to suffer large scale cavitation attached to their surfaces. Under such conditions the added mass effects differ from the expected ones in pure liquids. Moreover, the existence of small gaps between the structure and surrounding bodies filled with fluid also influence the dynamic response. A series of experiments and numerical simulations have been carried out with a truncated NACA0009 hydrofoil mounted as a cantilever beam at the LMH-EPFL cavitation tunnel. The three first modes of vibration have been determined and analysed under various hydrodynamic conditions ranging from air and still water to partial cavitation and supercavitation. A remote nonintrusive excitation system with piezoelectric patches has been used for the experiments. The effects of the cavity properties and the lateral gap size on the natural frequencies and mode shapes have been determined. As a result, the significance of several parameters in the design of such structures is discussed. (paper)

  16. Review of parameters influencing the structural response of a submerged body under cavitation conditions

    Science.gov (United States)

    Escaler, X.; De La Torre, O.; Farhat, M.

    2015-12-01

    Submerged structures that operate under extreme flows are prone to suffer large scale cavitation attached to their surfaces. Under such conditions the added mass effects differ from the expected ones in pure liquids. Moreover, the existence of small gaps between the structure and surrounding bodies filled with fluid also influence the dynamic response. A series of experiments and numerical simulations have been carried out with a truncated NACA0009 hydrofoil mounted as a cantilever beam at the LMH-EPFL cavitation tunnel. The three first modes of vibration have been determined and analysed under various hydrodynamic conditions ranging from air and still water to partial cavitation and supercavitation. A remote nonintrusive excitation system with piezoelectric patches has been used for the experiments. The effects of the cavity properties and the lateral gap size on the natural frequencies and mode shapes have been determined. As a result, the significance of several parameters in the design of such structures is discussed.

  17. Experimental research of a microjet cavitation

    Directory of Open Access Journals (Sweden)

    Olšiak Róbert

    2012-04-01

    Full Text Available The paper presents some results of a cavitation research behind a micro-orifice. Investigated were the conditions of the origin of cavitation represented by parameters such as upstream pressure, downstream pressure, liquid temperature and cavitation number. Presented are also images of a cavitating microjet made by the high speed high definition camera RedLake Y3. Dimensions of a microjet are: diameter 0,3 mm; length 0,5 mm.

  18. Cavitation erosion in sodium flow, sodium cavitation tunnel testing

    International Nuclear Information System (INIS)

    Courbiere, Pierre.

    1981-04-01

    The high-volume sodium flows present in fast neutron reactors are liable to induce cavitation phenomena in various portion of the sodium lines and pumps. The absence of sufficient data in this area led the C.E.A. to undertake an erosion research program in cavitating sodium flow. This paper discusses the considerations leading to the definition and execution of sodium cavitation erosion tests, and reviews the tests run with 400 0 C sodium on various steel grades: 316, 316 L, 316 Ti (Z8CNDT17-12), Poral (Z3CND18-12), 304 L and LN2 - clad 316 L (Ni coating-clad 316 L). Acoustic detection and signal processing methods were used with an instrument package designed and implemented at the Cadarache Nuclear Research Center

  19. Sonoluminescence and acoustic cavitation

    Science.gov (United States)

    Choi, Pak-Kon

    2017-07-01

    Sonoluminescence (SL) is light emission under high-temperature and high-pressure conditions of a cavitating bubble under intense ultrasound in liquid. In this review, the fundamentals of the interactions between the sound field and the bubble, and between bubbles are explained. Experimental results on high-speed shadowgraphy of bubble dynamics and multibubble SL are shown, demonstrating that the SL intensity is closely related to the bubble dynamics. SL studies of alkali-metal atom (Na and K) emission are summarized. The spectral measurements in solutions with different noble-gas dissolutions and in surfactant solutions, and the results of spatiotemporal separation of SL distribution strongly suggested that the site of alkali-metal atom emission is the gas phase inside bubbles. The spectral studies indicated that alkali-metal atom lines are composed of two kinds of lines: a component that is broadened and shifted from the original D lines arises from van der Waals molecules formed between alkali-metal atoms and noble-gas atoms under extreme conditions at bubble collapse. The other spectral component exhibiting no broadening and no shift was suggested to originate from higher temperature bubbles than those producing the broadened component.

  20. 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.

  1. A user-friendly technical set-up for infrared photography of forensic findings.

    Science.gov (United States)

    Rost, Thomas; Kalberer, Nicole; Scheurer, Eva

    2017-09-01

    Infrared photography is interesting for a use in forensic science and forensic medicine since it reveals findings that normally are almost invisible to the human eye. Originally, infrared photography has been made possible by the placement of an infrared light transmission filter screwed in front of the camera objective lens. However, this set-up is associated with many drawbacks such as the loss of the autofocus function, the need of an external infrared source, and long exposure times which make the use of a tripod necessary. These limitations prevented up to now the routine application of infrared photography in forensics. In this study the use of a professional modification inside the digital camera body was evaluated regarding camera handling and image quality. This permanent modification consisted of the replacement of the in-built infrared blocking filter by an infrared transmission filter of 700nm and 830nm, respectively. The application of this camera set-up for the photo-documentation of forensically relevant post-mortem findings was investigated in examples of trace evidence such as gunshot residues on the skin, in external findings, e.g. hematomas, as well as in an exemplary internal finding, i.e., Wischnewski spots in a putrefied stomach. The application of scattered light created by indirect flashlight yielded a more uniform illumination of the object, and the use of the 700nm filter resulted in better pictures than the 830nm filter. Compared to pictures taken under visible light, infrared photographs generally yielded better contrast. This allowed for discerning more details and revealed findings which were not visible otherwise, such as imprints on a fabric and tattoos in mummified skin. The permanent modification of a digital camera by building in a 700nm infrared transmission filter resulted in a user-friendly and efficient set-up which qualified for the use in daily forensic routine. Main advantages were a clear picture in the viewfinder, an auto

  2. 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

    Molding of thin and long parts by injection molding leads to special requirements for the mold in order to ensure proper filling and acceptable cycle time. This paper investigates the applicability of embedded induction heating for the improvement of the filling of thin long parts. The object...... selected for the investigation is a thin spiral. For the complete molding of the component, elevated mold temperatures are required. For this propose a new injection molding set-up was developed, which allows rapid heating of the cavity wall by an induction heating system. The temperature was measured...

  3. Royal Order of 12 December 1975 setting up a National Energy Committee

    International Nuclear Information System (INIS)

    1978-01-01

    The National Energy Committee was set up by Royal Order of 12 December 1975. Its duties are to advise on the general objectives of energy policy and its implementation. It supervises execution of the policy and makes recommendations on matters within its competence. The Committee is chaired by the Minister for Economic Affairs and Energy and is composed of representatives of the Government, trade unions, undertakings, consumers, gas and electricity committees, oil and coal industries and a delegate of the Planning Department. This Order repeals the Order of 17 July 1957 creating an Energy Advisory Council. (NEA) [fr

  4. Experimental set-up for advanced aeroelastic tests on sectional models

    Czech Academy of Sciences Publication Activity Database

    Král, Radomil; Pospíšil, Stanislav; Náprstek, Jiří

    2016-01-01

    Roč. 40, č. 1 (2016), s. 3-13 ISSN 0732-8818 R&D Projects: GA ČR GA103/09/0094; GA AV ČR IAA200710902; GA MŠk(CZ) ED1.1.00/02.0060 Institutional support: RVO:68378297 Keywords : bridge aeroelasticity * wind tunnel * experimental set-up * non- linear response Subject RIV: JM - Building Engineering Impact factor: 0.932, year: 2016 http://link.springer.com/article/10.1007%2Fs40799-015-0004-6

  5. 29 July 1991-Royal Order setting up a Higher Institute for Emergency Planning

    International Nuclear Information System (INIS)

    1991-01-01

    This Institute was set up in accordance with national legislation on protection against major industrial risks and Directive 89/618 Euratom on informing the general public about health protection measures to be applied and steps to be taken in the event of a radiological emergency. The Institute's duties include: organizing training for emergency planning and assistance; promoting the exchange of ideas on emergency planning between the authorities and operators of installations which could generate major risks, including nuclear installations; and disseminating adequate and regularly updated information to persons involved in emergency assistance on the risks they incur and the protection measures to be taken. (NEA)

  6. 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.

  7. Setting-up of a direct reading emission spectrometer and its adaptation for plutonium handling

    International Nuclear Information System (INIS)

    Page, A.G.; Godbole, S.V.; Kulkarni, M.J.; Porwal, N.K.; Thulasidas, S.K.; Sastry, M.D.; Srinivasan, P.S.

    1986-01-01

    A Jarrell-Ash 750 AtomComp 1100 series direct reading emission spectrometer was set up and its performance features were checked with regard to analysis of uranium-based samples using d.c. arc/inductively coupled argon plasma excitation techniques. The instrument has been subsequently modified to enable handling of plutonium-based samples. The modifications include building up of a specially designed glove-box around the excitation sources and consequent changes in the electro-mechanical controls associated with them. The modified system was extensively used for the trace metal assay of FBTR fuel sample. (author)

  8. 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.

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

    Science.gov (United States)

    Stc Hamilton, Karen E; Sullivan, Frank M; Donnan, Peter T; Taylor, Rex; Ikenwilo, Divine; Scott, Anthony; Baker, Chris; Wyke, Sally

    2005-01-01

    To investigate the set up and operation of a Managed Clinical Network for cardiac services and assess its impact on patient care. 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. 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 not statistically significant. There was no difference

  10. Feasibility for the setting up of a multipurpose food irradiation facility in Senegal

    International Nuclear Information System (INIS)

    Diop, Y.; Marchioni, E.; Hasswlmann, C.; Ba, D.; Kuntz, F.

    2002-01-01

    The setting up of a cobalt-60 (activity 500 kCi) irradiation facility in the highest populated region of Senegal (Dakar district) to treat a wide range of foodstuffs for local consumption (millet/sorghum, rice, maize, cowpeas, potatoes, onions, mangoes, citrus fruits and dried fishes) is considered as profitable for a private investor or a Senegalese food producer (or trader), provided the tonnage of foodstuffs treated is adequate, more than 22,000 t·kGy, i.e. a total tonnage above 77,000 t, taking into account the irradiation doses used for the various foodstuffs. (author)

  11. Cavitation and multiphase flow forum - 1985

    International Nuclear Information System (INIS)

    Hoyt, J.W.; Furuya, O.

    1985-01-01

    This book presents the papers given at a conference on fluid flow. Topics considered at the conference included cavitation inception, bubble growth, cavitation noise, holography, axial flow pumps, vortices, cavitation erosion, two-phase flow in nozzles, coal slurry valves, hopper flows of granular materials, helium bubble transport in a closed vertical duct, and a numerical model for flow in a venturi scrubber

  12. Supernova hydrodynamics

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1981-01-01

    The explosion of a star supernova occurs at the end of its evolution when the nuclear fuel in its core is almost, or completely, consumed. The star may explode due to a small residual thermonuclear detonation, type I SN or it may collapse, type I and type II SN leaving a neutron star remnant. The type I progenitor should be thought to be an old accreting white dwarf, 1.4 M/sub theta/, with a close companion star. A type II SN is thought to be a massive young star 6 to 10 M/sub theta/. The mechanism of explosion is still a challenge to our ability to model the most extreme conditions of matter and hydrodynamics that occur presently and excessively in the universe. 39 references

  13. 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...

  14. Physical hydrodynamics

    CERN Document Server

    Guyon, Etienne; Petit, Luc; Mitescu, Catalin D

    2015-01-01

    This new edition is an enriched version of the textbook of fluid dynamics published more than 10 years ago. It retains the same physically oriented pedagogical perspective. This book emphasizes, as in the first edition, experimental inductive approaches and relies on the study of the mechanisms at play and on dimensional analysis rather than more formal approaches found in many classical textbooks in the field. The need for a completely new version also originated from the increase, over the last few decades, of the cross-overs between the mechanical and physical approaches, as is visible in international meetings and joint projects. Hydrodynamics is more widely linked today to other fields of experimental sciences: materials, environment, life sciences and earth sciences, as well as engineering sciences.

  15. Biodiesel Production from Waste Cooking Oil Using Hydrodinamic Cavitation

    Directory of Open Access Journals (Sweden)

    Muhammad Supardan

    2013-04-01

    Full Text Available The aim of this research was to study biodiesel production from low cost feedstock of waste cooking oil (WCO using hydrodynamic cavitation apparatus. A two-step processes esterification process and transesterification process using hydrodynamic cavitation for the production of biodiesel from WCO is presented. The first step is acid-catalyzed esteri-fication process for reducing free fatty acid (FFA content of WCO and followed by base-catalyzed transesterification process for converting WCO to biodiesel as the second step. The result of esterification process with methanol to oil molar ratio of 5 and temperature of 60 oC showed that the initial acid value of WCO of 3.9 mg KOH/g can be decreased to 1.81 mg KOH/g in 120 minutes. The highest yield of biodiesel in transesterification process of 89.4% obtained at reaction time of 150 minutes with methanol to oil molar ratio of 6. The biodiesel produced in the experiment was analyzed by gas chromatography-mass spectrometry (GC-MS, which showed that it mainly contained five fatty acid methyl esters. In addition, the properties of biodiesel showed that all of the fuel properties met the Indonesian National Standard (INS No. 04-7182-2006 for biodiesel. 

  16. Introduction to hydrodynamics

    International Nuclear Information System (INIS)

    Wilkins, M.L.

    1979-01-01

    Various aspects of hydrodynamics and elastic--plastic flow are introduced for the purpose of defining hydrodynamic terms and explaining what some of the important hydrodynamic concepts are. The first part covers hydrodynamic theory; and discussed fundamental hydrodynamic equations, discontinuities, and shock, detonation, and elastic--plastic waves. The second part deals with applications of hydrodynamic theory to material equations of state, spall, Taylor instabilities, and detonation pressure measurements

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

    International Nuclear Information System (INIS)

    Lubritto, C.; Petraglia, A.; Paribello, G.; Formosi, R.; Rosa, M. de; Vetromile, C.; Palmieri, A.; D'Onofrio, A.; Di Bella, G.; Giannini, V.

    2006-01-01

    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.)

  18. Test set up description and performances for HAWAII-2RG detector characterization at ESTEC

    Science.gov (United States)

    Crouzet, P.-E.; ter Haar, J.; de Wit, F.; Beaufort, T.; Butler, B.; Smit, H.; van der Luijt, C.; Martin, D.

    2012-07-01

    In the frame work of the European Space Agency's Cosmic Vision program, the Euclid mission has the objective to map the geometry of the Dark Universe. Galaxies and clusters of galaxies will be observed in the visible and near-infrared wavelengths by an imaging and spectroscopic channel. For the Near Infrared Spectrometer instrument (NISP), the state-of-the-art HAWAII-2RG detectors will be used, associated with the SIDECAR ASIC readout electronic which will perform the image frame acquisitions. To characterize and validate the performance of these detectors, a test bench has been designed, tested and validated. This publication describes the pre-tests performed to build the set up dedicated to dark current measurements and tests requiring reasonably uniform light levels (such as for conversion gain measurements). Successful cryogenic and vacuum tests on commercial LEDs and photodiodes are shown. An optimized feed through in stainless steel with a V-groove to pot the flex cable connecting the SIDECAR ASIC to the room temperature board (JADE2) has been designed and tested. The test set up for quantum efficiency measurements consisting of a lamp, a monochromator, an integrating sphere and set of cold filters, and which is currently under construction will ensure a uniform illumination across the detector with variations lower than 2%. A dedicated spot projector for intra-pixel measurements has been designed and built to reach a spot diameter of 5 μm at 920nm with 2nm of bandwidth [1].

  19. Sensor set-up for wireless measurement of automotive rim and wheel parameters in laboratory conditions

    Science.gov (United States)

    Borecki, M.; Prus, P.; Korwin-Pawlowski, M. L.; Rychlik, A.; Kozubel, W.

    2017-08-01

    Modern rims and wheels are tested at the design and production stages. Tests can be performed in laboratory conditions and on the ride. In the laboratory, complex and costly equipment is used, as for example wheel balancers and impact testers. Modern wheel balancers are equipped with electronic and electro-mechanical units that enable touch-less measurement of dimensions, including precision measurement of radial and lateral wheel run-out, automatic positioning and application of the counterweights, and vehicle wheel set monitoring - tread wear, drift angles and run-out unbalance. Those tests are performed by on-wheel axis measurements with laser distance meters. The impact tester enables dropping of weights from a defined height onto a wheel. Test criteria are the loss of pressure of the tire and generation of cracks in the wheel without direct impact of the falling weights. In the present paper, a set up composed of three accelerometers, a temperature sensor and a pressure sensor is examined as the base of a wheel tester. The sensor set-up configuration, on-line diagnostic and signal transmission are discussed.

  20. Contribution to the development of the multidetector AMPHORA. Design of the electronic set up

    International Nuclear Information System (INIS)

    Stassi, P.

    1989-01-01

    The multidetector AMPHORA has been designed and built to be used to detect and identify all the particles produced in intermediate energy heavy ion reactions. This installation consist of 140 detectors built with CsI(TI) + NE102A and CsI(TI) + NE213 scintillators, covering nearly 81% of the solid angle around the target. These detectors can identify light charged particles, intermediate mass fragments and neutrons. The electronic set up associated is compact and requires little manual adjustment. It is built with special CAMAC modules which have the folowing functions: A 4 channel constant fraction discriminator and gate generator, a 16 channel charge to digital converter (12 bits), a 8 channel time to digital converter (12 bits), a 16 channel pile-up detector and a fast decision module. This thesis contains a detailed explanation of the principle and operation of the set up. It also contains a part which describes the way to connect all the modules of the electronic configuration for AMPHORA [fr

  1. 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.)

  2. 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.

  3. Set-up and Test Procedure for Suction Installation and Uninstallation of Bucket Foundation

    DEFF Research Database (Denmark)

    Koteras, Aleksandra Katarzyna

    This technical report describes the set-up and the test procedures for installation and uninstallation of medium-scale model of bucket foundation that can be performed in the geotechnical part of laboratory in Aalborg University. The installation of bucket foundation can be tested with the use of......) and loading frame used for those tests have been already used for axially static and cyclic loading of piles (Thomassen, 2015a) and for axially static and cyclic loading of bucket foundation (Vaitkunaite et al., 2015).......This technical report describes the set-up and the test procedures for installation and uninstallation of medium-scale model of bucket foundation that can be performed in the geotechnical part of laboratory in Aalborg University. The installation of bucket foundation can be tested with the use...... of suction under the bucket lid or by applying additional force through the hydraulic piston, forcing the bucket to penetrate into the soil. Tests for uninstallation are performed also with the use of water pressure, as a reverse process to the suction installation. Both installation and uninstallation tests...

  4. CHALLENGES IN SETTING UP QUALITY CONTROL IN DIAGNOSTIC RADIOLOGY FACILITIES IN NIGERIA.

    Science.gov (United States)

    Inyang, S O; Egbe, N O; Ekpo, E

    2015-01-01

    The Nigerian Nuclear Regulatory Authority (NNRA) was established to regulate and control the use of radioactive and radiation emitting sources in Nigeria. Quality control (QC) on diagnostic radiology equipment form part of the fundamental requirements for the authorization of diagnostic radiology facilities in the Country. Some quality control tests (output, exposure linearity and reproducibility) were measured on the x-ray machines in the facilities that took part in the study. Questionnaire was developed to evaluate the frequencies at which QC tests were conducted in the facilities and the challenges in setting up QC. Results show great variation in the values of the QC parameters measured. Inadequate cooperation by facilities management, lack of QC equipment and insufficient staff form the major challenges in setting up QC in the facilities under study. The responses on the frequencies at which QC tests should be conducted did not correspond to the recommended standards; indicating that personnel were not familiar with QC implementation and may require further training on QC.

  5. Ebola 2014: Setting up a port health screening programme at an international train station.

    Science.gov (United States)

    Cleary, Vivien; Wynne-Evans, Edward; Freed, James; Fleet, Katie; Thorn, Simone; Turbitt, Deborah

    2017-12-01

    An outbreak of Ebola virus disease (EVD) began in Guinea in December 2013 and was declared a Public Health Emergency of International Concern by the World Health Organization in August 2014. In October, the UK government tasked Public Health England (PHE) to set up EVD screening at key ports. The key aim of port-of-entry screening was to identify passengers coming from areas with high risk of EVD, and give them advice to raise their awareness of symptoms and what actions to take. Direct flights from Sierra Leone, Guinea or Liberia had all been cancelled, so intelligence on passenger numbers and routes was used to identify the most commonly used routes from the affected countries into the UK. One of these was St Pancras International train station. Screening had never previously been implemented at a UK train station so had to be set up from scratch. Key to the success of this was excellent multi-agency working between PHE, the UK Border Force, Eurostar, Network Rail and the Cabinet Office. This paper gives an overview of the activation of EVD screening at St Pancras International and the subsequent decommissioning.

  6. Diagnosis and outcome of birth asphyxia in resource constrained health care set up

    International Nuclear Information System (INIS)

    Zaman, S.; Shah, S.A.; Mehmood, S.; Shahzad, S.; Munir, M.; Mushtaq, A.

    2017-01-01

    Objective: To determine morbidity and mortality of neonates with low APGAR score in a resource constrained health care set up. Study Design: Prospective descriptive study. Place and Duration of Study: The study was carried out in combined military hospital Attock, from Jan 2013 to Jan 2015. Material and Methods: All term neonates with 37 completed weeks of gestation and APGAR score less than 7 were included in the study. APGAR score was calculated by an attending pediatrician, gynecologist or trained female nurse at 0 and 5 minutes. In Neonatal Intensive Care Unit [NICU] the babies were daily examined by pediatrician. Outcome was documented in term of morbidity i.e. fits and mortality i.e. death of babies. Results: Total number of neonates included in the study were 85 of which 55 (65%) were males and 30 (35%) were females. Of the total neonates 65 (76%) were discharged in satisfactory conditions and 20 (24%) expired during stay in the hospital. The mean APGAR score of newborns was 4.98 +- 0.98 at 5 minutes. During stay in hospital 46 (54%) were diagnosed to have hypoxic ischemic encephalopathy 2 (HIE2), those diagnosed with HIE3 were 5 (6%) and the rest 14 (16%) with HIE1. Conclusion: Low APGAR score is an important cause of admission to NICU. Low APGAR score was found associated with increased risk of fits in neonates and one of the most important cause of mortality in our set up. (author)

  7. Research of vibration resistance of non-rigid shafts turning with various technological set-ups

    Directory of Open Access Journals (Sweden)

    Vasilevykh Sergey L.

    2017-01-01

    Full Text Available The article considers the definition of the stability range of a dynamic system for turning non-rigid shafts with different technological set-ups: standard and developed ones; they are improved as a result of this research. The topicality of the study is due to the fact that processing such parts is associated with significant difficulties caused by deformation of the workpiece under the cutting force as well as occurrence of vibration of the part during processing, they are so intense and in practice they force to significantly reduce the cutting regime, recur to multiple-pass operation, lead to premature deterioration of the cutter, as a result, reduce the productivity of machining shafts on metal-cutting machines. In this connection, the purpose of the present research is to determine the boundaries of the stability regions with intensive turning of non-rigid shafts. In the article the basic theoretical principles of construction of a mathematical system focused on the process of non-free cutting of a dynamic machine are justified. By means of the developed mathematical model interrelations are established and legitimacies of influence of various technological set-ups on stability of the dynamic system of the machine-tool-device-tool-blank are revealed. The conducted researches allow to more objectively represent difficult processes that occur in a closed dynamic system of a machine.

  8. Thermo-hydrodynamic lubrication in 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 thermo-hydrodynamic and the thermo-elasto-hydrodynamic lubrication. The algorithms are methodically detailed and each section is thoroughly illustrated.

  9. 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

  10. Use of hydrodynamic disintegration to accelerate anaerobic digestion of surplus activated sludge.

    Science.gov (United States)

    Grübel, Klaudiusz; Machnicka, Alicja

    2009-12-01

    Hydrodynamic disintegration of activated sludge resulted in organic matter and polymers transfer from the solid phase into the liquid phase. Disintegration by hydrodynamic cavitation had a positive effect on the degree and rate of excess sludge anaerobic digestion. Also, addition of a part of anaerobic digested sludge containing adapted microorganisms resulted in acceleration of the process. The disruption of cells of foam microorganisms and addition to the digestion process led to an increase of biogas production.

  11. Size effects on cavitation instabilities

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2006-01-01

    growth is here analyzed for such cases. A finite strain generalization of a higher order strain gradient plasticity theory is applied for a power-law hardening material, and the numerical analyses are carried out for an axisymmetric unit cell containing a spherical void. In the range of high stress...... triaxiality, where cavitation instabilities are predicted by conventional plasticity theory, such instabilities are also found for the nonlocal theory, but the effects of gradient hardening delay the onset of the instability. Furthermore, in some cases the cavitation stress reaches a maximum and then decays...... as the void grows to a size well above the characteristic material length....

  12. Swell-generated Set-up and Infragravity Wave Propagation Over a Fringing Coral Reef: Implications for Wave-driven Inundation of Atoll Islands

    Science.gov (United States)

    Cheriton, O. M.; Storlazzi, C. D.; Rosenberger, K. J.; Quataert, E.; van Dongeren, A.

    2014-12-01

    The Republic of the Marshall Islands is comprised of 1156 islands on 29 low-lying atolls with a mean elevation of 2 m that are susceptible to sea-level rise and often subjected to overwash during large wave events. A 6-month deployment of wave and tide gauges across two shore-normal sections of north-facing coral reef on the Roi-Namur Island on Kwajalein Atoll was conducted during 2013-2014 to quantify wave dynamics and wave-driven water levels on the fringing coral reef. Wave heights and periods on the reef flat were strongly correlated to the water levels. On the fore reef, the majority of wave energy was concentrated in the incident band (5-25 s); due to breaking at the reef crest, however, the wave energy over the reef flat was dominated by infragravity-band (25-250 s) motions. Two large wave events with heights of 6-8 m at 15 s over the fore reef were observed. During these events, infragravity-band wave heights exceeded the incident band wave heights and approximately 1.0 m of set-up was established over the innermost reef flat. This set-up enabled the propagation of large waves across the reef flat, reaching maximum heights of nearly 2 m on the innermost reef flat adjacent to the toe of the beach. XBEACH models of the instrument transects were able to replicate the incident waves, infragravity waves, and wave-driven set-up across the reef when the hydrodynamic roughness of the reef was correctly parameterized. These events led to more than 3 m of wave-driven run-up and inundation of the island that drove substantial morphological change to the beach face.

  13. 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)

  14. CAV-OX (trade name) Cavitation Oxidation Process Magnum Water Technology, Inc. applications analysis report. Report for November 1992-November 1993

    Energy Technology Data Exchange (ETDEWEB)

    Stacy, G.L.

    1994-05-01

    The CAV-OX process was developed by magnum Water Technology to destroy organic contaminants in water. The process uses hydrodynamic cavitation, ultraviolet (UV) radiation, and hydrogen peroxide to oxidize organic compounds present in water at or below milligrams per liter levels. This treatment technology produces no air emissions and generated no sludge or spent media that requires further processing, handling, or disposal. Ideally, the end products are water, carbon dioxide, halides, and in some cases, organic acids. The process uses mercury vapor lamps to generate UV radiation. The principal oxidants in the process, hydroxyl radicals, are produced by hydrodynamic cavitation and direct photolysis of hydrogen peroxide at UV wavelengths.

  15. 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

  16. 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

  17. Formation of a cavitation cluster in the vicinity of a quasi-empty rupture

    Science.gov (United States)

    Bol'shakova, E. S.; Kedrinskiy, V. K.

    2017-09-01

    The presentation deals with one of the experimental and numerical models of a quasi-empty rupture in the magma melt. This rupture is formed in the liquid layer of a distilled cavitating fluid under shock loading within the framework of the problem formulation with a small electromagnetic hydrodynamic shock tube. It is demonstrated that the rupture is shaped as a spherical segment, which retains its topology during the entire process of its evolution and collapsing. The dynamic behavior of the quasi-empty rupture is analyzed, and the growth of cavitating nuclei in the form of the boundary layer near the entire rupture interface is found. It is shown that rupture implosion is accompanied by the transformation of the bubble boundary layer to a cavitating cluster, which takes the form of a ring-shaped vortex floating upward to the free surface of the liquid layer. A p-κ mathematical model is formulated, and calculations are performed to investigate the implosion of a quasi-empty spherical cavity in the cavitating liquid, generation of a shock wave by this cavity, and dynamics of the bubble density growth in the cavitating cluster by five orders of magnitude.

  18. Removal of bacteria Legionella pneumophila, Escherichia coli, and Bacillus subtilis by (super)cavitation.

    Science.gov (United States)

    Šarc, Andrej; Kosel, Janez; Stopar, David; Oder, Martina; Dular, Matevž

    2018-04-01

    In sufficient concentrations, the pathogenic bacteria L. pneumophila can cause a respiratory illness that is known as the "Legionnaires" disease. Moreover, toxic Shiga strains of bacteria E. coli can cause life-threatening hemolytic-uremic syndrome. Because of the recent restrictions imposed on the usage of chlorine, outbreaks of these two bacterial species have become more common. In this study we have developed a novel rotation generator and its effectiveness against bacteria Legionella pneumophila and Escherichia coli was tested for various types of hydrodynamic cavitation (attached steady cavitation, developed unsteady cavitation and supercavitation). The results show that the supercavitation was the only effective form of cavitation. It enabled more than 3 logs reductions for both bacterial species and was also effective against a more persistent Gram positive bacteria, B. subtilis. The deactivation mechanism is at present unknown. It is proposed that when bacterial cells enter a supercavitation cavity, an immediate pressure drop occurs and this results in bursting of the cellular membrane. The new rotation generator that induced supercavitation proved to be economically and microbiologically far more effective than the classical Venturi section (super)cavitation. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Hydrodynamic dispersion

    International Nuclear Information System (INIS)

    Pryce, M.H.L.

    1985-01-01

    A dominant mechanism contributing to hydrodynamic dispersion in fluid flow through rocks is variation of travel speeds within the channels carrying the fluid, whether these be interstices between grains, in granular rocks, or cracks in fractured crystalline rocks. The complex interconnections of the channels ensure a mixing of those parts of the fluid which travel more slowly and those which travel faster. On a macroscopic scale this can be treated statistically in terms of the distribution of times taken by a particle of fluid to move from one surface of constant hydraulic potential to another, lower, potential. The distributions in the individual channels are such that very long travel times make a very important contribution. Indeed, while the mean travel time is related to distance by a well-defined transport speed, the mean square is effectively infinite. This results in an asymmetrical plume which differs markedly from a gaussian shape. The distribution of microscopic travel times is related to the distribution of apertures in the interstices, or in the microcracks, which in turn are affected in a complex way by the stresses acting on the rock matrix

  20. Setting up decommissioning funds for nuclear facilities - a competence problem for EURATOM

    International Nuclear Information System (INIS)

    Danwitz, Th. von

    2003-01-01

    The nuclear package presented by the European Commission in the autumn of 2002 has added considerable practical significance to the problem of the vertical limits of competence between the Community and its member states within the framework of the Euratom Treaty. The question most important to Germany is the authority of the European Atomic Energy Community to oblige its member states to set up funds for financing the decommissioning of nuclear facilities. As the Euratom Treaty contains no explicit competences of Euratom for regulations of this type, the article examines the content and range of Art. 30 ff. of the Euratom Treaty, the unwritten authority resulting from factual connections and the nature of the problems involved, looks at the importance of international agreements as far as legal competences are implied, and deals with a possible competence based on the right to amend the Treaty under Art. 203, Euratom Treaty. (orig.) [de

  1. A new X-ray absorption experimental set-up dedicated to DeNOx catalysis

    International Nuclear Information System (INIS)

    Revel, R.; Bazin, D.; Seigneurin, A.; Barthe, P.; Dubuisson, J.M.; Decamps, T.; Sonneville, H.; Poher, J.J.; Maire, F.; Lefrancois, P.

    1999-01-01

    In this paper, we present a complete in situ X-ray absorption reaction cell that simulates DeNO x experimental conditions. In this device, the sample is placed at high temperature under the flow of a complex mixture of reactive gases (NO, C 3 H 6 , O 2 , N 2 ). Particular attention has been paid to the material and design of the sample holders in order to avoid preferential gas circulation and thus ensure a true diffusion of the reactive gases on the catalyst. Moreover, precise control of the gas flow is maintained by means of mass flow controllers, and the safety of the set-up is assured by CO, CO 2 and NO detectors directly relayed to an electronic device, which is itself linked to the various mass flow controllers. Finally, the possibilities of this device are illustrated through the in situ XANES study of a Cu-ZSM-5 catalytic system

  2. Specific heat measurement set-up for quench condensed thin superconducting films.

    Science.gov (United States)

    Poran, Shachaf; Molina-Ruiz, Manel; Gérardin, Anne; Frydman, Aviad; Bourgeois, Olivier

    2014-05-01

    We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films.

  3. Setting up your own business. Facing the future as an entrepreneur.

    Science.gov (United States)

    Brent, N J

    1990-01-01

    Other areas of setting up and running a business also are important to explore, especially if the business plans to use employees. You will become an employer, and you must be familiar with rules and regulations that include areas such as the employee's right to a safe workplace, worker's compensation laws, unemployment compensation laws and tax liabilities, antidiscrimination laws, and wage and tax laws. If independent contractors are going to be used, you must recognize that well-developed contracts are a necessity. If you are going to market a new product, consult with an attorney whose practice concentrates in trademark and patent law before the product is shared with others. Being well informed about the proposed business venture, not only before its establishment but as it develops and grows, can help you be in the best position to have a successful business.

  4. FTIR free-jet set-up for the high resolution spectroscopic investigation of condensable species

    Science.gov (United States)

    Georges, R.; Bonnamy, A.; Benidar, A.; Decroi, M.; Boissoles, J.

    2002-05-01

    An existing experimental set-up combining Fourier transform infrared (FTIR) spectroscopy and free-jet cooling has been modified significantly to allow high resolution studies of the spectrum of monomer species which are liquid under standard conditions. Evaporation of the liquid samples is controlled by a condenser apparatus which is described. A supersonic planar expansion issuing from a narrow aperture is preferred for its very high cooling rate. Such an expansion, probed with a pitot tube, has a zone of limited temperature gradient close to the nozzle exit. The continuum isentropic model appears well suited to describing the thermodynamic properties of the flow up to a high number of nozzle diameters downstream. High resolution spectra of benzene and methanol have been recorded in the 3 µm wavelength range, and their analysis demonstrates a well defined rotational temperature in the 20-25 K range.

  5. Setting up and running an advanced light microscopy and imaging facility.

    Science.gov (United States)

    Sánchez, Carlos; Muñoz, Ma Ángeles; Villalba, Maite; Labrador, Verónica; Díez-Guerra, F Javier

    2011-07-01

    During the last twenty years, interest in light microscopy and imaging techniques has grown in various fields, such as molecular and cellular biology, developmental biology, and neurobiology. In addition, the number of scientific articles and journals using these techniques is rapidly increasing. Nowadays, most research institutions require sophisticated microscopy systems to cover their investigation demands. In general, such instruments are too expensive and complex to be purchased and managed by a single laboratory or research group, so they have to be shared with other groups and supervised by specialized personnel. This is the reason why microscopy and imaging facilities are becoming so important at research institutions nowadays. In this unit, we have gathered and presented a number of issues and considerations from our own experience that we hope will be helpful when planning or setting up a new facility.

  6. 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.

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

    International Nuclear Information System (INIS)

    Galvis, J. A.; Herrera, E.; Buendía, A.; Guillamón, I.; Vieira, S.; Suderow, H.; Azpeitia, J.; Luccas, R. F.; Munuera, C.; García-Hernandez, M.

    2015-01-01

    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 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

  8. Friction degradation and set-up effects in hard clays offshore Congo and Angola

    International Nuclear Information System (INIS)

    Colliat, J.L.; Vergobbi, P.; Puech, A.

    1993-01-01

    Piles driven into stiff to hard clays encountered offshore Congo and Angola clearly show both clay-type effects which are (1) friction degradation, with very low driving resistances during continuous driving, and (2) set-up after driving interruptions. Both phenomena were studied by back-analysis of driving records, including results of pile driving monitoring. It allowed one to deduce the friction distribution along the piles during driving; show how the shaft friction at any depth reduces as the pile is driven further into the ground; and show that the shaft friction after driving delays can be close to the estimated static friction capacity of the piles. The SRD calculation method proposed by the authors takes the friction degradation effect into account, leading to improved pile drivability predictions. Four case histories are presented to illustrate the results obtained

  9. Neutron polarizing set-up of the Sofia IRT research reactor

    International Nuclear Information System (INIS)

    Krezhov, K.; Mikhajlova, V.; Okorokov, A.

    1990-01-01

    Neutron polarizing set-up of one of the horizontal beam tubes of the IRT-200 research reactor of the Bulgarian Institute of Nuclear Research and Nuclear Energy is presented. Neutron mirrors are extensively used in an effort to compensate the moderate reactor beam intensity by the high reflected intensity and wide-band transmittance of the mirror neutron guides. Time-to-flight technique using a slotted neutron absorbing chopper with a horizontal rotation axis has been applied to obtain the exit neutron spectra. Beam polarization and flipping ratios have been determined. Cadmium ratio in the polarized beam has been found almost 10 4 and the average polarization has been measured to be higher than 96%. 3 figs, 3 refs

  10. 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.

  11. Setting up a new CZO in the Ganga basin: instrumentation, stakeholder engagement and preliminary observations

    Science.gov (United States)

    Gupta, S.; Tripathi, S.; Sinha, R.; Karumanchi, S. H.; Paul, D.; Tripathi, S. N.; Sen, I. S.; Dash, S. K.

    2017-12-01

    The Ganga plains represent the abode of more than 400 million people and a region of severe anthropogenic disturbance to natural processes. Changing agricultural practices, inefficient use of water, contamination of groundwater systems, and decrease in soil fertility are some of the issues that have affected the long-term resilience of hydrological processes. The quantification of these processes demands a network of hydro-meteorological instrumentation, low-cost sensors, continuous engagement of stakeholders and real time data transmission at a fine interval. We have therefore set up a Critical Zone Observatory (CZO) in a small watershed (35km2) that forms an intensively managed rural landscape consisting of 92% of agricultural land in the Pandu River Basin (a small tributary of the Ganga River). Apart from setting up a hydro-meteorological observatory, the major science questions we want to address relate to development of water balance model, understanding the soil-water interaction and estimation of nutrient fluxes in the watershed. This observatory currently has various types of sensors that are divided into three categories: (a) spatially not dense but temporally fine data, (b) spatially dense but temporally not fine data and(c) spatially dense and temporally fine data. The first category represent high-cost sensors namely automatic weather stations that are deployed at two locations and provide data at 15-minute interval. The second category includes portable soil moisture, discharge and groundwater level at weekly/ biweekly interval. The third category comprises low-cost sensors including automatic surface and groundwater level sensors installed on open wells to monitor the continuous fluctuation of water level at every 15 minutes. In addition to involving the local communities in data collection (e.g. manual rainfall measurement, water and soil sampling), this CZO also aims to provide relevant information to them for improving their sustainability. The

  12. Development of Data Acquisition Set-up for Steady-state Experiments

    Science.gov (United States)

    Srivastava, Amit K.; Gupta, Arnab D.; Sunil, S.; Khan, Ziauddin

    2017-04-01

    For short duration experiments, generally digitized data is transferred for processing and storage after the experiment whereas in case of steady-state experiment the data is acquired, processed, displayed and stored continuously in pipelined manner. This requires acquiring data through special techniques for storage and on-the-go viewing data to display the current data trends for various physical parameters. A small data acquisition set-up is developed for continuously acquiring signals from various physical parameters at different sampling rate for long duration experiment. This includes the hardware set-up for signal digitization, Field Programmable Gate Arrays (FPGA) based timing system for clock synchronization and event/trigger distribution, time slicing of data streams for storage of data chunks to enable viewing of data during acquisition and channel profile display through down sampling etc. In order to store a long data stream of indefinite/long time duration, the data stream is divided into data slices/chunks of user defined time duration. Data chunks avoid the problem of non-access of server data until the channel data file is closed at the end of the long duration experiment. A graphical user interface has been developed in Lab VIEW application development environment for configuring the data acquisition hardware and storing data chunks on local machine as well as at remote data server through Python for further data access. The data plotting and analysis utilities have been developed with Python software, which provides tools for further data processing. This paper describes the development and implementation of data acquisition for steady-state experiment.

  13. 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

  14. Developing and setting up of a nuclear medicine information management system

    International Nuclear Information System (INIS)

    Baghel, N.S.; Asopa, R.; Nayak, U.N.; Rajan, M.G.R.; Subhalakshmi, P.V.; Shailaja, A.; Rajashekharrao, B.; Karunanidhi, Y.R.

    2010-01-01

    Full text: With the advent and progress of information technology in the present decade, high-performance networks are being installed in hospitals to implement an effective and reliable Hospital Information Management Systems (HIMS). The Radiation Medicine Centre (RMC), is one of the earliest and largest nuclear medicine centres in India and several thousand patients undergo diagnostic as well as therapeutic procedures with different radiopharmaceuticals. The evolution towards a fully digital department of nuclear medicine is driven by expectations of not only improved patient management but also a well-defined workflow along with prompt and quality patient services. The aim was to develop and set up a practical and utility based Nuclear Medicine Information Management System (NMIMS) for various functional procedures at RMC. A customised NMIMS is developed with M/s ECIL using ASP.NET and SQL server technology facilitated by an IBM x3650 M3 Server, 18 thin-clients/desktop PCs and Windows 2008 server operating system and MS-SQL 2005 server software. The various modules have been developed to meet the requirements of different activities pertaining to patient appointment and scheduling, clinical assessment, radiopharmacy procedures, imaging and non-imaging studies and protocols, in-vitro laboratory tests, in-patient and out-patient treatment procedures, radiation protection and regulatory aspects and other routine operational procedures associated with patient management at RMC. The menus are developed as per scheduled workflow (SWF) in the department. The various aspects of SWF have been designed to ensure smooth, easy and trouble free patient management. Presently, the NMIMS has been developed excluding imaging data and we are in the process of setting up Picture Archiving Communication System (PACS) integrated to the existing database system, which will archive and facilitate imaging data in DICOM format in order to make a paperless department. The developed NMIMS

  15. 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.

  16. How To Set Up Your Own Small Business. Service Company Case Study. Manufacturing Firm Case Study. Retail Store Case Study.

    Science.gov (United States)

    Fallek, Max

    This collection of case studies is intended for use in a course in setting up a small business. The first, a case study of the process of setting up a service company, covers analyzing the pros and cons of starting one's own business, assessing the competition and local market, and selecting a site for and financing the business. The principal…

  17. Scratch to state-of-the-art: setting up a new robotic facility in a developing country.

    Science.gov (United States)

    Bora, G S; Mavuduru, R S; Devana, S K; Singh, S K; Mandal, A K

    2018-03-01

    The potential challenges encountered for setting up a robotic assisted surgical facility in developing country like India are many. We describe the initial hurdles and troubleshooting in establishing a facility of such kind. This experience might help to decrease initial hiccups in setting up such an innovative technology at other institutes.

  18. A novel device for hazardous substances degradation based on double-cavitating-jets impingement: Parameters optimization and efficiency assessment.

    Science.gov (United States)

    Tao, Yuequn; Cai, Jun; Huai, Xiulan; Liu, Bin

    2017-08-05

    Hydrodynamic cavitation is an effective advanced oxidation process. But sometimes it cannot obtain satisfactory treatment efficiency by using hydrodynamic cavitation individually, so it is necessary to introduce intensive methods. Based on double-cavitating-jets impingement, this paper presents a novel device that has advantages of strong heat and mass transfer and efficient chemical reactions. Based on the device, a series of experimental investigations on degradation of a basic dye, i.e. Rhodamine B were carried out. Significant Rhodamine B removal from aqueous solution was observed during 2h treatment and the degradation reaction conformed to pseudo-first-order kinetics. The synergetic effects between double-cavitating-jets impingement and Fenton chemistry on simultaneous degradation of Rhodamine B were confirmed. Both single-variable experiments and orthogonal experiments were carried out to study the effects of initial hydrogen peroxide, ferrous sulfate and Rhodamine B concentrations and the optimum conditions were found out. Effects of jet inlet pressure in the range of 6-12MPa and solution pH value in the range of 2-8 were also investigated. The cavitation yield was evaluated to assess the energy efficiency. The present treatment scheme showed advantages in terms of reducing the demand of hydrogen peroxide concentration and enhancing the treatment efficiency in large scale operation. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Influence of cavitation on the passive behaviour of duplex stainless steels in aqueous LiBr solutions

    International Nuclear Information System (INIS)

    Garcia-Garcia, D.M.; Garcia-Anton, J.; Igual-Munoz, A.

    2008-01-01

    The objective of this work is to study the influence of cavitation on the passive behaviour of EN 1.4462, its filler metal (EN 1.4462F), and the welded metal (EN 1.4462W) obtained by Gas Tungsten Arc Welding using electrochemical techniques. The hydrodynamic conditions of the medium were modified using an ultrasonic-induced cavitation facility. Potentiostatic experiments were used to study the effects of cavitation on the passive behaviour of the alloys. The experiments were carried out in 850 g/L LiBr solutions with and without an inhibitor (Lithium Chromate). The solution with Li 2 CrO 4 (commercial solution) contains LiOH as the pH regulator. The potentiodynamic cyclic curves of the stainless steels under the static condition were used to set the values of the imposed potentials. In this work, the electrochemical behaviour of the alloys described by the potentiodynamic curves has been related to their passive behaviour under potentiostatic conditions when the pulses of cavitation were applied. The results demonstrate that cavitation affects the passive behaviour of the alloys; the influence depends on the potential applied and on the presence or absence of chromates in the medium. Only under certain circumstances the hydrodynamic conditions can suppose a breakdown of passive film formed under static conditions

  20. Stochastic-field cavitation model

    International Nuclear Information System (INIS)

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

    2013-01-01

    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

  1. 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.

  2. 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

  3. Chromatin Hydrodynamics

    Science.gov (United States)

    Bruinsma, Robijn; Grosberg, Alexander Y.; Rabin, Yitzhak; Zidovska, Alexandra

    2014-01-01

    Following recent observations of large scale correlated motion of chromatin inside the nuclei of live differentiated cells, we present a hydrodynamic theory—the two-fluid model—in which the content of a nucleus is described as a chromatin solution with the nucleoplasm playing the role of the solvent and the chromatin fiber that of a solute. This system is subject to both passive thermal fluctuations and active scalar and vector events that are associated with free energy consumption, such as ATP hydrolysis. Scalar events drive the longitudinal viscoelastic modes (where the chromatin fiber moves relative to the solvent) while vector events generate the transverse modes (where the chromatin fiber moves together with the solvent). Using linear response methods, we derive explicit expressions for the response functions that connect the chromatin density and velocity correlation functions to the corresponding correlation functions of the active sources and the complex viscoelastic moduli of the chromatin solution. We then derive general expressions for the flow spectral density of the chromatin velocity field. We use the theory to analyze experimental results recently obtained by one of the present authors and her co-workers. We find that the time dependence of the experimental data for both native and ATP-depleted chromatin can be well-fitted using a simple model—the Maxwell fluid—for the complex modulus, although there is some discrepancy in terms of the wavevector dependence. Thermal fluctuations of ATP-depleted cells are predominantly longitudinal. ATP-active cells exhibit intense transverse long wavelength velocity fluctuations driven by force dipoles. Fluctuations with wavenumbers larger than a few inverse microns are dominated by concentration fluctuations with the same spectrum as thermal fluctuations but with increased intensity. PMID:24806919

  4. 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

  5. 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.

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

    Science.gov (United States)

    Malato, S; Blanco, J; Vidal, A; Fernández, P; Cáceres, J; Trincado, P; Oliveira, J C; Vincent, M

    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 TiO2 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 m3 of water with a 100 m2 collector-aperture area and aqueous aerated suspensions of polycrystalline TiO2 irradiated by sunlight. Fully automatic control reduces operation and maintenance manpower. Plant behaviour has been compared (using dichloroacetic acid and cyanide at 50 mg l(-1) initial concentration as model compounds) with the small CPC pilot plants installed at the Plataforma Solar de Almería several years ago. The first results with high-content cyanide (1 g l(-1)) waste water are presented and plant treatment capacity is calculated.

  8. Secondary electron images obtained with a standard photoelectron emission microscope set-up

    International Nuclear Information System (INIS)

    Benka, Oswald; Zeppenfeld, Peter

    2005-01-01

    The first results of secondary electron images excited by 3-4.3 keV electrons are presented. The images are obtained with a standard FOCUS-PEEM set-up equipped with an imaging energy filter (IEF). The electron gun was mounted on a standard PEEM entrance flange at an angle of 25 deg. with respect to the sample surface. A low extraction voltage of 500 V was used to minimize the deflection of the electron beam by the PEEM extraction electrode. The secondary electron images are compared to photoelectron images excited by a standard 4.9 eV UV lamp. In the case of a Cu pattern on a Si substrate it is found that the lateral resolution without the IEF is about the same for electron and photon excitation but that the relative electron emission intensities are very different. The use of the IEF reduces the lateral resolution. Images for secondary electron energies between eV 1 and eV 2 were obtained by setting the IEF to -V 1 and -V 2 ∼-(V 1 +5V) potentials and taking the difference of both images. Images up to 100 eV electron energies were recorded. The material contrast obtained in these difference images is discussed in terms of a secondary electron and photoelectron emission model and secondary electron energy spectra measured with a LEED-Auger spectrometer

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

    Directory of Open Access Journals (Sweden)

    C. TSABARIS

    2005-06-01

    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.

  10. Setting up a parathyroid multidisciplinary team meeting: one year's experience, outcomes and learning points.

    Science.gov (United States)

    Hancox, S H; Sinnott, J D; Kirkland, P; Lipscomb, D; Owens, E; Howlett, D C

    2018-03-01

    A parathyroid multidisciplinary team meeting was set up at East Sussex Healthcare Trust, from November 2014 to November 2015, in order to improve and streamline services for patients with parathyroid pathology. Data were collected on all new referrals for hyperparathyroidism, and on the outcomes for each patient discussed at the meeting, including the number of operations and management outcomes. A survey was sent out to the members of the multidisciplinary team meeting to determine their perception of its effectiveness. Seventy-nine new referrals were discussed throughout the year; 43 per cent were recommended for surgery, 41 per cent had a trial of conservative or medical management before re-discussion, and 16 per cent required further imaging. Ninety-two per cent of patients underwent an ultrasound, single-photon emission computed tomography/computed tomography or nuclear medicine (sestamibi) scan prior to the meeting. All ultrasound scans were performed by a consultant radiologist. The multidisciplinary team meeting has been successful, with perceived benefits for patients, improved imaging evaluation and efficiency of referral pathways, leading to more appropriate patient management.

  11. The new dedicated PIXE set-up at the National Environmental Research Institute, Denmark

    International Nuclear Information System (INIS)

    Kemp, Ka ring re; Waahlin, Peter

    1999-01-01

    The Niels Bohr Institute in Copenhagen was in the beginning of the 70'es one of the early places for PIXE. Contributions were made to the theoretical interpretation of the PIXE spectra as well as the practical application. The home-made 4 MV van de Graaff accelerator at the Niels Bohr Institute was an excellent tool for PIXE. The accelerator, which was used for many years, has now found its place on a museum after more than 40 years of active service. A dedicated PIXE set-up has now been established at the National Environmental Research Institute using a new 1.7 MV Tandem Pelletron (5SDH) from NEC. The main application is elemental analysis of outdoor aerosols. The main work is unsophisticated macro analyses, which do not push the equipment to its limits. This enables automated analysis of about 10,000 samples per year using very limited manpower resources. The research focuses on the contribution from various source types to the atmosphere over Europe, the North Atlantic and Greenland. Source compositions and their temporal variations are studied

  12. Special problems of setting up nuclear medicine in a developing country

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    There are some special problems in setting up nuclear medicine in a developing country. They can be briefly described in the form of the following general rules. 1) Impossible triangle. For the practice of nuclear medicine, three things are needed: Instrument, Radiopharmaceutical and a Patient. In a developing country, these three become three sides of an impossible triangle. When the radiopharmaceutical is available, the instrument may not be working; when the instrument is functioning, the radiopharmaceutical may not have been obtained from the foreign supplier; and when both are there, the patient might no longer be in the hospital. Three sides of this triangle never join to become a congruent whole. 2) Reverse square law. Further away one is from the source of supply of instruments and radiopharmaceuticals, the problems multiply by the square of this distance. 3) Future of nuclear medicine is tied to the electrical supply available in a developing country. These problems related to power supply are described in the Chapter on maintenance of instruments

  13. 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...

  14. Special problems of setting up nuclear medicine in a developing country

    Energy Technology Data Exchange (ETDEWEB)

    Ganatra, R D

    1993-12-31

    There are some special problems in setting up nuclear medicine in a developing country. They can be briefly described in the form of the following general rules. 1) Impossible triangle. For the practice of nuclear medicine, three things are needed: Instrument, Radiopharmaceutical and a Patient. In a developing country, these three become three sides of an impossible triangle. When the radiopharmaceutical is available, the instrument may not be working; when the instrument is functioning, the radiopharmaceutical may not have been obtained from the foreign supplier; and when both are there, the patient might no longer be in the hospital. Three sides of this triangle never join to become a congruent whole. 2) Reverse square law. Further away one is from the source of supply of instruments and radiopharmaceuticals, the problems multiply by the square of this distance. 3) Future of nuclear medicine is tied to the electrical supply available in a developing country. These problems related to power supply are described in the Chapter on maintenance of instruments

  15. Set-up and methods for SiPM Photo-Detection Efficiency measurements

    International Nuclear Information System (INIS)

    Zappalà, G.; Acerbi, F.; Ferri, A.; Gola, A.; Paternoster, G.; Zorzi, N.; Piemonte, C.

    2016-01-01

    In this work, a compact set-up and three different methods to measure the Photo-Detection Efficiency (PDE) of Silicon Photomultipliers (SiPMs) and Single-Photon Avalanche Diodes (SPADs) are presented. The methods, based on either continuous or pulsed light illumination, are discussed in detail and compared in terms of measurement precision and time. For the SiPM, these methods have the feature of minimizing the effect of both the primary and correlated noise on the PDE estimation. The PDE of SiPMs (produced at FBK, Trento, Italy) was measured in a range from UV to NIR, obtaining similar results with all the methods. Furthermore, the advantages of measuring, when possible, the PDE of SPADs (of the same technology and with the same layout of a single SiPM cell) instead of larger devices are also discussed and a direct comparison between measurement results is shown. Using a SPAD, it is possible to reduce the measurement complexity and uncertainty since the correlated noise sources are reduced with respect to the SiPM case.

  16. A new instrumental set-up for polarized neutron scattering experiments

    International Nuclear Information System (INIS)

    Schmidt, Wolfgang; Ohl, Michael

    2005-01-01

    Neutron scattering with polarization analysis is a powerful tool to determine magnetic structures and excitations. A common setup is to mount the sample at the center of a Helmholtz-type coil which can provide a magnetic field of any direction at the sample position and also a guide field along the neutron flight paths around the sample. Recent experiments showed quite a high demand for measurements at low momentum transfers. For the corresponding low scattering angles air scattering gives rise to a very large background. For this reason we have extended the standard setup to a combination of a large vacuum tank surrounded by electrical coils. The vacuum tank eliminates the air scattering and we can use the polarization analysis down to the lowest accessible momentum transfers. The coils themselves also show some new features: In contrary to the classic (symmetric) coil distribution we use an asymmetric setup which gives the advantage of a larger scattering window. Due to a more sophisticated current distribution this modified coil arrangement needs not to be rotated for different scattering conditions. The whole set-up will soon be available at IN12, a cold neutrons three-axis spectrometer operated by FZ Juelich in collaboration with CEA Grenoble as a CRG-B instrument at the Institut Laue Langevin in Grenoble

  17. 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...

  18. Computational fluid dynamics simulation of indoor climate in low energy buildings: Computational set up

    Directory of Open Access Journals (Sweden)

    Risberg Daniel

    2017-01-01

    Full Text Available In this paper CFD was used for simulation of the indoor climate in a part of a low energy building. The focus of the work was on investigating the computational set up, such as grid size and boundary conditions in order to solve the indoor climate problems in an accurate way. Future work is to model a complete building, with reasonable calculation time and accuracy. A limited number of grid elements and knowledge of boundary settings are therefore essential. An accurate grid edge size of around 0.1 m was enough to predict the climate according to a grid independency study. Different turbulence models were compared with only small differences in the indoor air velocities and temperatures. The models show that radiation between building surfaces has a large impact on the temperature field inside the building, with the largest differences at the floor level. Simplifying the simulations by modelling the radiator as a surface in the outer wall of the room is appropriate for the calculations. The overall indoor climate is finally compared between three different cases for the outdoor air temperature. The results show a good indoor climate for a low energy building all around the year.

  19. Cavitation nucleation in gelatin: Experiment and mechanism.

    Science.gov (United States)

    Kang, Wonmo; Adnan, Ashfaq; O'Shaughnessy, Thomas; Bagchi, Amit

    2018-02-01

    Dynamic cavitation in soft materials is becoming increasingly relevant due to emerging medical implications such as the potential of cavitation-induced brain injury or cavitation created by therapeutic medical devices. However, the current understanding of dynamic cavitation in soft materials is still very limited, mainly due to lack of robust experimental techniques. To experimentally characterize cavitation nucleation under dynamic loading, we utilize a recently developed experimental instrument, the integrated drop tower system. This technique allows quantitative measurements of the critical acceleration (a cr ) that corresponds to cavitation nucleation while concurrently visualizing time evolution of cavitation. Our experimental results reveal that a cr increases with increasing concentration of gelatin in pure water. Interestingly, we have observed the distinctive transition from a sharp increase (pure water to 1% gelatin) to a much slower rate of increase (∼10× slower) between 1% and 7.5% gelatin. Theoretical cavitation criterion predicts the general trend of increasing a cr , but fails to explain the transition rates. As a likely mechanism, we consider concentration-dependent material properties and non-spherical cavitation nucleation sites, represented by pre-existing bubbles in gels, due to possible interplay between gelatin molecules and nucleation sites. This analysis shows that cavitation nucleation is very sensitive to the initial configuration of a bubble, i.e., a non-spherical bubble can significantly increase a cr . This conclusion matches well with the experimentally observed liquid-to-gel transition in the critical acceleration for cavitation nucleation. From a medical standpoint, understanding dynamic cavitation within soft materials, i.e., tissues, is important as there are both potential injury implications (blast-induced cavitation within the brain) as well as treatments utilizing the phenomena (lithotripsy). In this regard, the main

  20. Cavitation noise studies on marine propellers

    Science.gov (United States)

    Sharma, S. D.; Mani, K.; Arakeri, V. H.

    1990-04-01

    Experimental observations are described of cavitation inception and noise from five model propellers, three basic and two modified, tested in the open jet section of the Indian Institute of Science high-speed water tunnel facility. Extensive experiments on the three basic propellers of different design, which included visualization of cavitation and measurements of noise, showed that the dominant type of cavitation was in the form of tip vortex cavitation, accompanied by leading edge suction side sheet cavitation in its close vicinity, and the resultant noise depended on parameters such as the advance coefficient, the cavitation number, and the propeller geometry. Of these, advance coefficient was found to have the maximum influence not only on cavitation noise but also on the inception of cavitation. Noise levels and frequencies of spectra obtained from all the three basic propellers at conditions near inception and different advance coefficient values, when plotted in the normalized form as suggested by Blake, resulted in a universal spectrum which would be useful for predicting cavitation noise at prototype scales when a limited extent of cavitation is expected in the same form as observed on the present models. In an attempt to delay the onset of tip vortex cavitation, the blades of two of the three basic propellers were modified by drilling small holes in the tip and leading edge areas. Studies on the modified propellers showed that the effectiveness of the blade modification was apparently stronger at low advance coefficient values and depended on the blade sectional profile. Measurements of cavitation noise indicated that the modification also improved the acoustic performance of the propellers as it resulted in a complete attenuation of the low-frequency spectral peaks, which were prominent with the basic propellers. In addition to the above studies, which were conducted under uniform flow conditions, one of the basic propellers was tested in the simulated

  1. Pump cavitation and inducer design

    International Nuclear Information System (INIS)

    Heslenfeld, M.W.; Hes, M. de

    2002-01-01

    Details of past work on sodium pump development and cavitation studies executed mainly for SNR 300 were reported earlier. Among the requirements for large sodium pumps are long life (200000 hours up to 300000 hours) and small size of impeller and pump, fully meeting the process and design criteria. These criteria are the required 'Q, H, r characteristics' in combination with a low NPSH value and the avoidance of cavitation damage to the pump. The pump designer has to develop a sound hydraulic combination consisting of suction arrangement, impeller design and diffuser. On the other hand the designer is free to choose an optimal pump speed. The pump speed in its turn influences the rotor dynamic pump design and the pump drive. The introduction of the inducer as an integral part of the pump design is based on following advantages: no tip cavitation; (possible) cavitation bubbles move to the open centre due to centrifugal forces on the fluid; the head of the inducer improves the inlet conditions of the impeller. The aim of an inducer is the increase in the suction specific speed (SA value) of a pump whereby the inducer functions as a pressure source improving the impeller inlet conditions. With inducer-impeller combinations values up to SA=15000 are realistic. With the use of an inducer the overall pump sizes can be reduced with Ca. 30%. Pumps commonly available have SA values up to a maximum of ca. 10000. A development programme was executed for SNR 300 in order to reach an increase of the suction specific speed of the impeller from SA 8200 to SA 11000. Further studies to optimize pumps design for the follow up line introduced the 'inducer acting as a pre-impeller' development. This programme was executed in the period 1979-1981. At the FDO premises a scale 1 2.8 inducer impeller combination with a suction specific speed SA=15000 was developed, constructed and tested at the water test rig. This water test rig is equipped with a perspex pipe allowing also visualisation

  2. Scale effect on bubble growth and cavitation inception in cavitation susceptibility meters

    International Nuclear Information System (INIS)

    Shen, Y.T.; Gowing, S.

    1985-01-01

    The Reynolds number alone is not adequate to predict cavitation inception scaling. Recent experiments on headforms once again show that the cavitation inception data are very sensitive to the nuclei tensile strength which, in turn depends on the velocity scale. This paper theoretically investigates the influence of Reynolds number and velocity scale on cavitation inception in a cavitation susceptibility meter. The numerical examples given are based on a single bubble spherical model

  3. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Numerical solution for gate induced vibration due to under flow cavitation

    International Nuclear Information System (INIS)

    Sadrnezhad, S. A.

    2001-01-01

    Among the many forces to which hydraulic structures are exposed to, the forces induced by cavitation incident are of typical hydrodynamic unknown forces. The aim of this study is to define these forces as coupled fluid-structure interaction under two dynamic effects. The first dynamic effect which incorporates facilities for dealing with cavitation fluid is based on the appearance and bursting of vapor bubbles. The second hydrodynamic effect is dynamic excitation mechanism of the structure. In fluid-structure interaction, both the structure behavior and fluid are considered linear. Fluids can take some tension the extent of which depends on concentration and size of micro bubbles present; nevertheless, if the absolute pressure drops to a value close to the vapor pressure of the fluid, bubbles are formed and cavitation phenomena occurs. In this paper a fixed-wheel gate under the head pressure of a reservoir is considered to be affected by under flow cavitation. Normally, partially opened gates induce energy dissipation resulting in high turbulence, causing negative pressure and cavitation at the back and this exits the gate vibration. Moreover, there are several mechanisms which may cause heavy, self-excited vibration. According to the proposed method, a time function presenting the oscillation and pressure fluctuation in the vicinity of gate lip is estimated. This estimation is based on the parameters obtained from a two dimensional solution of flow under the gate lip. Accordingly, periodic time variable nodal forces are calculated and applied to gate lip element nodes. A transient dynamic solution of the gate, while its lip is sustaining nodal forces is estimated as time function. The results for the most server modal deformation of the structure time history of some critical elements and variation of equivalent force versus time are presented

  5. Sound source location in cavitating tip vortices

    International Nuclear Information System (INIS)

    Higuchi, H.; Taghavi, R.; Arndt, R.E.A.

    1985-01-01

    Utilizing an array of three hydrophones, individual cavitation bursts in a tip vortex could be located. Theoretically, four hydrophones are necessary. Hence the data from three hydrophones are supplemented with photographic observation of the cavitating tip vortex. The cavitation sound sources are found to be localized to within one base chord length from the hydrofoil tip. This appears to correspond to the region of initial tip vortex roll-up. A more extensive study with a four sensor array is now in progress

  6. Cavitation occurrence around ultrasonic dental scalers

    OpenAIRE

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

    2009-01-01

    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 a...

  7. Contributions to some cavitation problems in turbomachinery

    OpenAIRE

    Arakeri, VH

    1999-01-01

    In the present article, three problems associated with cavitation in turbomachinery are discussed. The first one deals with the potential application of recent understanding in cavitation inception to similar problems in turbomachinery. The second considers the thermodynamic effects in developed cavitation. This has relevance to turbopump operation using fluids other than water. Old correlations to predict the above effect are summarized and a new correlation is proposed. Lastly, the possible...

  8. Decree No. 89-85 of 8 February 1989 setting up a Council on Technological Risk Prevention

    International Nuclear Information System (INIS)

    1989-01-01

    The Council set up by this Decree contributes to the assessment of collective risks arising from industrial activities, in particular nuclear activities, through its opinions, recommendations, studies, and proposes the relevant preventive actions to the Government. (NEA) [fr

  9. Disintegration of materials by cavitating microjets

    Directory of Open Access Journals (Sweden)

    Mlkvik M.

    2013-04-01

    Full Text Available In the paper is presented an investigation of material disintegration by cavitating microjets. Cavitating microjet develops behind the micro-orifice at high flow speeds, when local pressure drop initiates a cavitation phenomenon. Described is a method and presented are selected results of experiments. Experiments were carried out with 2 micro-orifices at different flow conditions (cavitation number, distance between sample and micro-orifice. Experiments are based on flow visualisation as well as on a character of material displacement.

  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. 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)

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

    Science.gov (United States)

    Iqbal, Azhar

    2006-04-01

    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 the input states are classical and perfectly anti-correlated, as for a classical correlation game. However, for a quantum correlation game, with an entangled singlet state as input, qualitatively different solutions are obtained. The second approach uses the result that when the predictions of a Local Hidden Variable (LHV) model are made to violate the Bell inequalities the result is that some probability measures assume negative values. With the requirement that classical games result when the predictions of a LHV model do not violate the Bell inequalities, our analysis looks at the impact which the emergence of negative probabilities has on the solutions of two-player games which are physically implemented using the EPR-type experiments.

  13. The second Dutch national survey on radon in dwellings. Set-up of the project

    International Nuclear Information System (INIS)

    Hiemstra, Y.; Stoop, P.; Lembrechts, J.

    1997-03-01

    In 1994 the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) commissioned RIVM to carry out a national survey on radon in dwellings, the set-up of which is described in this report. The goals of the survey were: (a) to determine the average and the range of the radon (222Rn) concentration in Dutch dwellings built since the previous survey in 1984, and (b) to quantify the relative contribution of radon from the building materials and from the soil to the indoor radon level in dwellings built in the course of the last decade. These data will be used for the selection of possible countermeasures and as a reference for evaluating the effectiveness of final regulations on radon. Two separate random samples from the Dutch housing stock were taken to answer these questions. A sample of about 1000 dwellings built between 1985 and 1993 in 52 municipalities was taken to answer the first question. The composition of the sample differs from the Dutch housing stock for a number of characteristics, the most obvious of which is the over-representation of single-family and private homes. A sample of about 450 single-family dwellings built in 14 municipalities on different soil types was taken to answer the second question. Two groups of municipalities were distinguished because of geographic differences in building practices: those where town houses predominate and those with mainly detached and semi-detached houses. Information on radon and its sources was collected through placement of alpha track detectors, installation of so-called PFT sources and passive samplers for air infiltration measurement, collection of soil samples and completion of a questionnaire on building and ventilation characteristics. The results of the study are dealt with in RIVM report no. 610058006. 8 figs., 9 tabs., 31 refs. 4 appendices

  14. Concept and set-up of an IR-gas sensor construction kit

    Science.gov (United States)

    Sieber, Ingo; Perner, Gernot; Gengenbach, Ulrich

    2015-10-01

    The paper presents an approach to a cost-efficient modularly built non-dispersive optical IR-gas sensor (NDIR) based on a construction kit. The modularity of the approach offers several advantages: First of all it allows for an adaptation of the performance of the gas sensor to individual specifications by choosing the suitable modular components. The sensitivity of the sensor e.g. can be altered by selecting a source which emits a favorable wavelength spectrum with respect to the absorption spectrum of the gas to be measured or by tuning the measuring distance (ray path inside the medium to be measured). Furthermore the developed approach is very well suited to be used in teaching. Together with students a construction kit on basis of an optical free space system was developed and partly implemented to be further used as a teaching and training aid for bachelor and master students at our institute. The components of the construction kit are interchangeable and freely fixable on a base plate. The components are classified into five groups: sources, reflectors, detectors, gas feed, and analysis cell. Source, detector, and the positions of the components are fundamental to experiment and test different configurations and beam paths. The reflectors are implemented by an aluminum coated adhesive foil, mounted onto a support structure fabricated by additive manufacturing. This approach allows derivation of the reflecting surface geometry from the optical design tool and generating the 3D-printing files by applying related design rules. The rapid fabrication process and the adjustment of the modules on the base plate allow rapid, almost LEGO®-like, experimental assessment of design ideas. Subject of this paper is modeling, design, and optimization of the reflective optical components, as well as of the optical subsystem. The realization of a sample set-up used as a teaching aid and the optical measurement of the beam path in comparison to the simulation results are

  15. Improving beam set-up using an online beam optics tool

    International Nuclear Information System (INIS)

    Richter, S.; Barth, W.; Franczak, B.; Scheeler, U.; Wilms, D.

    2004-01-01

    The GSI accelerator facility [1] consists of the Universal Linear Accelerator (Unilac), the heavy ion synchrotron SIS, and the Experimental Storage Ring (ESR). Two Unilac injectors with three ion source terminals provide ion species from the lightest such as hydrogen up to uranium. The High Current Injector (HSI) for low charge state ion beams provides mostly high intense but short pulses, whereas the High Charge State Injector (HLI) supplies long pulses with a high duty factor of up to 27%. Before entering the Alvarez section of the Unilac the ion beam from the HSI is stripped in a supersonic gas jet. Up to three different ion species can be accelerated for up to five experiments in a time-sharing mode. Frequent changes of beam energy and intensity during a single beam time period may result in time consuming set-up and tuning especially of the beam transport lines. To shorten these changeover times an online optics tool (MIRKO EXPERT) had been developed. Based on online emittance measurements at well-defined locations the beam envelopes are calculated using the actual magnet settings. With this input improved calculated magnet settings can be directly sent to the magnet power supplies. The program reads profile grid measurements, such that an atomized beam alignment is established and that steering times are minimized. Experiences on this tool will be reported. At the Unilac a special focus is put on high current operation with short but intense beam pulses. Limitations like missing non-destructive beam diagnostics, insufficient longitudinal beam diagnostics, insufficient longitudinal beam matching, and influence of the hard edged model for magnetic fields will be discussed. Special attention will be put on the limits due to high current effects with bunched beams. (author)

  16. Chart review of electroconvulsive therapy practice from a tertiary care geriatric mental health set up

    Directory of Open Access Journals (Sweden)

    Akanksha Sonal

    2017-01-01

    Full Text Available Introduction: Electroconvulsive therapy (ECT is frequently used treatment procedure, and is utilized more often for severe, treatment-resistant, or refractory psychiatric disorders. However, published data on the use of ECT is limited, more so for special population like older adults. Aim: The aim of the study was to explore the clinical, demographic, and diagnostic profiles of older adults, and the parameters of ECT treatment, in a tertiary care Geriatric Mental Health set up. Materials and Methods: Approval to review the case notes was obtained from the Institutional Ethical Committee. The individuals were aged 60 years and above and had received ECT between January 2014 and May 2017. The relevant details pertaining to the aims of the study were recorded in a spreadsheet. Results: Twenty-five courses (absolute number = 191 of ECT were given to 21 patients (mean age = 67.44 ± 9.8 years with mean of 7.64 ± 3.6 ECT per patient. Majority of the patients belonged to age group 60–69 years, and were male (81%. Depression was the most common diagnosis for giving ECT (43% in these individuals, and poor response to pharmacological treatment (81% was the most common indication. The mean duration of the seizure elicited was 28.8 ± 13.2 s, and a therapeutic response was seen in 86% of cases. No major complications were noted during ECT treatment. Conclusion: When used judiciously and with trained staff, ECT is an effective and relatively safe mode of treatment even in older adults.

  17. Optimally setting up directed searches for continuous gravitational waves in Advanced LIGO O1 data

    Science.gov (United States)

    Ming, Jing; Papa, Maria Alessandra; Krishnan, Badri; Prix, Reinhard; Beer, Christian; Zhu, Sylvia J.; Eggenstein, Heinz-Bernd; Bock, Oliver; Machenschalk, Bernd

    2018-02-01

    In this paper we design a search for continuous gravitational waves from three supernova remnants: Vela Jr., Cassiopeia A (Cas A) and G347.3. These systems might harbor rapidly rotating neutron stars emitting quasiperiodic gravitational radiation detectable by the advanced LIGO detectors. Our search is designed to use the volunteer computing project Einstein@Home for a few months and assumes the sensitivity and duty cycles of the advanced LIGO detectors during their first science run. For all three supernova remnants, the sky positions of their central compact objects are well known but the frequency and spin-down rates of the neutron stars are unknown which makes the searches computationally limited. In a previous paper we have proposed a general framework for deciding on what target we should spend computational resources and in what proportion, what frequency and spin-down ranges we should search for every target, and with what search setup. Here we further expand this framework and apply it to design a search directed at detecting continuous gravitational wave signals from the most promising three supernova remnants identified as such in the previous work. Our optimization procedure yields broad frequency and spin-down searches for all three objects, at an unprecedented level of sensitivity: The smallest detectable gravitational wave strain h0 for Cas A is expected to be 2 times smaller than the most sensitive upper limits published to date, and our proposed search, which was set up and ran on the volunteer computing project Einstein@Home, covers a much larger frequency range.

  18. Electromagnetic impact by microcellular base stations: analysis and guidelines for a correct setting up

    International Nuclear Information System (INIS)

    Licitra, G.; Reggiani, M.; Silvi, A.M.; Zari, A.; Ricci, A.

    2002-01-01

    During the last few years the development of mobile communications has required ever increasing number of base stations for both existing mobile operators and new ones. More and more users ask for a higher quality services so new technological solutions have been studied and applied to assure effective coverage for given geographical areas, as in squares or narrow streets, characterized by a very high traffic demand or where coverage by usual macro cells is very difficult. On the other side, modern societies of developed countries ask for a better and better quality of life and appropriate government policies. Several studies of national and international scientific organizations have been performed and are still in progress to establish any possible adverse effects on human health of non-ionizing radiation exposure. So, many governments, forced by public opinion pressure, have produced specific standards in agreement with scientific organization guidelines and prudent avoidance politics too. Nowadays, designing their networks, mobile operators have to respect requirements contained in these standards. So a hierarchical cellular system have been recently proposed to comply more easily with both coverage requirements and lower exposure limits. This new coverage strategy of geographical areas requires the presence of microcells beside the usual macro cells. In this paper the study of the distribution of the electromagnetic field levels produced by microcellular base stations characterized by different features and configurations is presented, in order to define a few guidelines for the correct setting up of antennas in compliance with current standard requirements. This is obtained comparing results of theoretical modeling, based on the radio electrical characteristics of each sources, and measurements data. Results achieved by measurements performed on a preliminary sample of microcells have been presented in this work

  19. Sustained release formulations of citronella oil nanoemulsion using cavitational techniques.

    Science.gov (United States)

    Agrawal, Naveen; Maddikeri, Ganesh L; Pandit, Aniruddha B

    2017-05-01

    Nanoemulsion synthesis has proven to be an effective way for transportation of immobile, insoluble bioactive compounds. Citronella Oil (lemongrass oil), a natural plant extract, can be used as a mosquito repellent and has less harmful effects compared to its available market counterpart DEET (N, N-Diethyl-meta-toluamide). Nanoemulsion of citronella oil in water was prepared using cavitation-assisted techniques while investigating the effect of system parameters like HLB (Hydrophilic Lipophilic Balance), surfactant concentration, input energy density and mode of power input on emulsion quality. The present work also examines the effect of emulsification on release rate to understand the relationship between droplet size and the release rate. Minimum droplet size (60nm) of the emulsion was obtained at HLB of 14, S/O 1 ratio of 1.0, ultrasound amplitude of 50% and irradiation time of 5min. This study revealed that hydrodynamic cavitation-assisted emulsification is more energy efficient compared to ultrasonic emulsification. It was also found that the release rate of nanoemulsion enhanced as the droplet size of emulsion reduced. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. 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.