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Sample records for submerged liquid jets

  1. Stabilizing effect of elasticity on the inertial instability of submerged viscoelastic liquid jets

    Science.gov (United States)

    Keshavarz, Bavand; McKinley, Gareth

    2017-11-01

    The stability of submerged Newtonian and viscoelastic liquid jets is studied experimentally using flow visualization. Precise control of the amplitude and frequency of the imposed linear perturbations is achieved through a piezoelectric actuator attached to the nozzle. By illuminating the jet with a strobe light driven at a frequency slightly less than the frequency of the perturbation we slow down the apparent motion by large factors ( 100 , 000) and capture the phenomena with high temporal and spatial resolution. Newtonian liquid jets become unstable at moderate Reynolds numbers (Rej 150) and sinuous or varicose patterns emerge and grow in amplitude. As the jet moves downstream, the varicose waves gradually pile up in the sinuous ones due to the difference in their corresponding wave speeds, leading to a unique chevron-like morphology. Experiments with model viscoelastic polymer solutions show that this inertial instability is fully stabilized sufficiently large levels of elasticity. We compare our experimental results with the theoretical predictions of an elastic Rayleigh equation for an axisymmetric jet and show that the presence of streamline tension is indeed the stabilizing effect for inertioelastic jets.

  2. Traction Drive Inverter Cooling with Submerged Liquid Jet Impingement on Microfinned Enhanced Surfaces (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S.; Narumanchi, S.; Moreno, G.

    2014-09-01

    Jet impingement is one means to improve thermal management for power electronics in electric-drive traction vehicles. Jet impingement on microfin-enhanced surfaces further augments heat transfer and thermal performance. A channel flow heat exchanger from a commercial inverter was characterized as a baseline system for comparison with two new prototype designs using liquid jet impingement on plain and microfinned enhanced surfaces. The submerged jets can target areas with the highest heat flux to provide local cooling, such as areas under insulated-gate bipolar transistors and diode devices. Low power experiments, where four diodes were powered, dissipated 105 W of heat and were used to validate computational fluid dynamics modeling of the baseline and prototype designs. Experiments and modeling used typical automotive flow rates using water-ethylene glycol as a coolant (50%-50% by volume). The computational fluid dynamics model was used to predict full inverter power heat dissipation. The channel flow and jet impingement configurations were tested at full inverter power of 40 to 100 kW (output power) on a dynamometer, translating to an approximate heat dissipation of 1 to 2 kW. With jet impingement, the cold plate material is not critical for the thermal pathway. A high-temperature plastic was used that could eventually be injection molded or formed, with the jets formed from a basic aluminum plate with orifices acting as nozzles. Long-term reliability of the jet nozzles and impingement on enhanced surfaces was examined. For jet impingement on microfinned surfaces, thermal performance increased 17%. Along with a weight reduction of approximately 3 kg, the specific power (kW/kg) increased by 36%, with an increase in power density (kW/L) of 12% compared with the baseline channel flow configuration.

  3. Applicability of submerged jet model to describe the liquid sample load into measuring chamber of micron and submillimeter sizes

    Science.gov (United States)

    Bulyanitsa, A. L.; Belousov, K. I.; Evstrapov, A. A.

    2017-11-01

    The load of a liquid sample into a measuring chamber is one of the stages of substance analysis in modern devices. Fluid flow is effectively calculated by numerical simulation using application packages, for example, COMSOL MULTIPHYSICS. In the same time it is often desirable to have an approximate analytical solution. The applicability of a submerged jet model for simulation the liquid sample load is considered for the chamber with sizes from hundreds micrometers to several millimeters. The paper examines the extent to which the introduction of amendments to the jet cutting and its replacement with an energy equivalent jet provide acceptable accuracy for evaluation of the loading process dynamics.

  4. Liquid developer jetting device

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Jun-ichi; Sasahara, Toshihiko; Nakamura, Manabu

    1996-02-06

    The liquid developer jetting device of the present invention comprises an air jetting nozzle for jetting pressurized air to an object to be tested. A liquid developer jetting nozzle is disposed near the air jetting nozzle for jetting a developer upwardly. The liquid developer jetting nozzle is situated in front of the air jetting nozzle for jetting the liquid developer in the direction perpendicular to the pressurized air jetted from the air jetting nozzle. In order to perform an penetration flaw detection test for an abut-welded portion of a drain nozzle disposed to the bottom of a reactor pressure vessel, the liquid developer jetting device is disposed in adjacent with the welded portion. Since the liquid developer jetted while dispersed from the developer jetting nozzle is further dispersed by the pressurized air from the air jetting nozzle, the density of the jetted the developer is made uniform despite of the short distance to the object to be tested. Accordingly, developing processing can be performed even in a restricted space. (I.N.).

  5. Surface Intermediate Zone of Submerged Turbulent Buoyant Jet in Current

    DEFF Research Database (Denmark)

    Chen, H. B.; Larsen, Torben

    1995-01-01

    This paper deals with the intermediate zone between the jet and plume stages of a submerged buoyant discharge from sea outfall in current. The stability criteria, plume width and height after the intermediate zone and the dilution within the intermediate region have been studied theoretically and...

  6. Liquid Film Diffusion on Reaction Rate in Submerged Biofilters

    DEFF Research Database (Denmark)

    Christiansen, Pia; Hollesen, Line; Harremoës, Poul

    1995-01-01

    Experiments were carried out in order to investigate the influence of liquid film diffusion on reaction rate in a submerged biofilter with denitrification and in order to compare with a theoretical study of the mass transfer coefficient. The experiments were carried out with varied flow, identified...... by the empty bed velocity of inflow and recirculation, respectively 1.3, 2.8, 5.6 and 10.9 m/h. The filter material consisted of 3 mm biostyren spheres. The results indicate that the influence of liquid film diffusion on reaction rate can be ignored....

  7. Time–frequency analysis of submerged synthetic jet

    Science.gov (United States)

    Kumar, Abhay; Saha, Arun K.; Panigrahi, P. K.

    2017-12-01

    The coherent structures transport the finite body of fluid mass through rolling which plays an important role in heat transfer, boundary layer control, mixing, cooling, propulsion and other engineering applications. A synthetic jet in the form of a train of vortex rings having coherent structures of different length scales is expected to be useful in these applications. The propagation and sustainability of these coherent structures (vortex rings) in downstream direction characterize the performance of synthetic jet. In the present study, the velocity signal acquired using the S-type hot-film probe along the synthetic jet centerline has been taken for the spectral analysis. One circular and three rectangular orifices of aspect ratio 1, 2 and 4 actuating at 1, 6 and 18 Hz frequency have been used for creating different synthetic jets. The laser induced fluorescence images are used to study the flow structures qualitatively and help in explaining the velocity signal for detection of coherent structures. The study depicts four regions as vortex rollup and suction region (X/D h ≤ 3), steadily translating region (X/D h ≤ 3–8), vortex breakup region (X/Dh ≤ 4–8) and dissipation of small-scale vortices (X/D h ≤ 8–15). The presence of coherent structures localized in physical and temporal domain is analyzed for the characterization of synthetic jet. Due to pulsatile nature of synthetic jet, analysis of velocity time trace or signal in time, frequency and combined time–frequency domain assist in characterizing the signatures of coherent structures. It has been observed that the maximum energy is in the first harmonic of actuation frequency, which decreases slowly in downstream direction at 6 Hz compared to 1 and 18 Hz of actuation.

  8. Effect of geometrical parameters on submerged cavitation jet discharged from profiled central-body nozzle

    Science.gov (United States)

    Yang, Minguan; Xiao, Shengnan; Kang, Can; Wang, Yuli

    2013-05-01

    The flow characteristics of cavitation jets are essential issues among relevant studies. The physical properties of the jet are largely determined by the geometrical parameters of the nozzle. The structure and cavitation jets characteristics of the angular-nozzle and the self-resonating cavitation nozzle have been extensively studied, but little research is conducted in the central-body cavitation nozzle mainly because of its hard processing and the cavitation jet effect not satisfactory. In this paper, a novel central-body nozzle (a non-plunger central-body nozzle with square outlet) is studied to solve above problems. Submerged jets discharged from the novel central-body nozzle are simulated, employing the full cavitation model. The impact of nozzle configuration on jet properties is analyzed. The analysis results indicate that when central-body relative diameter keeps constant, there is an optimal contraction degree of nozzle's outlet, which can induce intense cavitation in the jet. The central-body relative diameter also affects jet profiles. In the case of large central-body relative diameter, most of the bubbles settle in the jet core. On the contrary, a smaller relative diameter makes bubbles concentrate in the interface between the jet and its surrounding fluid. Moreover, the shorter outlet part allows the cavitation zone further extend in both the axial and racial directions. The research results further consummate the study on the central-body nozzles and the correlation between cavitation jet and the structure, and elementarily reveal the mechanism of cavitation jet produced in a non-plunger novel central-body nozzle and the effect of the structure parameters on the cavitation jet, moreover, provide the theoretical basis for the optimal design of the nozzle.

  9. Experimental studies of the stress state of the surface layer of detailat treatment with submerged jets

    Directory of Open Access Journals (Sweden)

    Олександр Олександрович Анділахай

    2015-03-01

    Full Text Available In the instrument and electrical industry was the use of the method of abrasive machining submerged jet, which is the most promising method for abrasive blasting of small parts of low stiffness. This method eliminates the main drawback сhip plants - abrasion channel nozzles or injection nozzles, but the state of the surface layer of machined parts are poorly understood and to make maximum use of the potential to provide the required quality parameters. The study of the state of the surfaces of parts resulting from abrasive blasting traditional methods, dedicated work, which define quality indicators: microhardness depth residual stress, as well as their nature (compressive, tensile. However, known from the literature values correspond to the conditions of surface treatment of parts in a fixed state with an abrasive material through the feed nozzle, and therefore the dynamics of the interaction of a single abrasive grain and significantly different parts. The process in question, and different modes of processing characteristics of the abrasive grains. In the paper, a series of experimental studies designed to assess the state of machined surfaces of parts as a result of abrasion submerged jets. It is established that during the treatment the non-oriented disorderly traces overlay the abrasive grains on the treated surface, thereby forming a tight skin layer thickness of 4 - 5 micrometers. Processed surface gets cold working, as evidenced by the study of microhardness before and after abrasive machining in a free state submerged jets

  10. Stable Liquid Jets Bouncing off Soft Gels

    Science.gov (United States)

    Daniel, Dan; Yao, Xi; Aizenberg, Joanna

    2018-01-01

    A liquid jet can stably bounce off a sufficiently soft gel by following the contour of the dimple created upon impact. This new phenomenon is insensitive to the wetting properties of the gels and was observed for different liquids over a wide range of surface tensions, γ =24 -72 mN /m . In contrast, other jet rebound phenomena are typically sensitive to γ : only a high γ jet rebounds off a hard solid (e.g. superhydrophobic surface) and only a low γ jet bounces off a liquid bath. This is because an air layer must be stabilized between the two interfaces. For a soft gel, no air layer is necessary and the jet rebound remains stable even when there is direct liquid-gel contact.

  11. Scale resolving computation of submerged wall jets on flat wall with different roughness heights

    Science.gov (United States)

    Paik, Joongcheol; Bombardelli, Fabian

    2014-11-01

    Scale-adaptive simulation is used to investigate the response of velocity and turbulence in submerged wall jets to abrupt changes from smooth to rough beds. The submerged wall jets were experimentally investigated by Dey and Sarkar [JFM, 556, 337, 2006] at the Reynolds number of 17500 the Froude number of 4.09 and the submergence ratio of 1.12 on different rough beds that were generated by uniform sediments of different median diameters The SAS is carried out by means of a second-order-accurate finite volume method in space and time and the effect of bottom roughness is treated by the approach of Cebeci (2004). The evolution of free surface is captured by employing the two-phase volume of fluid (VOF) technique. The numerical results obtained by the SAS approach, incorporated with the VOF and the rough wall treatment, are in good agreement with the experimental measurements. The computed turbulent boundary layer grows more quickly and the depression of the free surface is more increased on the rough wall than those on smooth wall. The size of the fully developed zone shrinks and the decay rate of maximum streamwise velocity and Reynolds stress components are faster with increase in the wall roughness. Supported by NSF and NRF of Korea.

  12. Experimental Investigation of Jet-Induced Mixing of a Large Liquid Hydrogen Storage Tank

    Science.gov (United States)

    Lin, C. S.; Hasan, M. M.; Vandresar, N. T.

    1994-01-01

    Experiments have been conducted to investigate the effect of fluid mixing on the depressurization of a large liquid hydrogen storage tank. The test tank is approximately ellipsoidal, having a volume of 4.89 m(exp 3) and an average wall heat flux of 4.2 W/m(exp 2) due to external heat input. A mixer unit was installed near the bottom of the tank to generate an upward directed axial jet flow normal to the liquid-vapor interface. Mixing tests were initiated after achieving thermally stratified conditions in the tank either by the introduction of hydrogen gas into the tank or by self-pressurization due to ambient heat leak through the tank wall. The subcooled liquid jet directed towards the liquid-vapor interface by the mixer induced vapor condensation and caused a reduction in tank pressure. Tests were conducted at two jet submergence depths for jet Reynolds numbers from 80,000 to 495,000 and Richardson numbers from 0.014 to 0.52. Results show that the rate of tank pressure change is controlled by the competing effects of subcooled jet flow and the free convection boundary layer flow due to external tank wall heating. It is shown that existing correlations for mixing time and vapor condensation rate based on small scale tanks may not be applicable to large scale liquid hydrogen systems.

  13. Generation Mechanism and Prediction Model for Low Frequency Noise Induced by Energy Dissipating Submerged Jets during Flood Discharge from a High Dam.

    Science.gov (United States)

    Lian, Jijian; Zhang, Wenjiao; Guo, Qizhong; Liu, Fang

    2016-06-15

    As flood water is discharged from a high dam, low frequency (i.e., lower than 10 Hz) noise (LFN) associated with air pulsation is generated and propagated in the surrounding areas, causing environmental problems such as vibrations of windows and doors and discomfort of residents and construction workers. To study the generation mechanisms and key influencing factors of LFN induced by energy dissipation through submerged jets at a high dam, detailed prototype observations and analyses of LFN are conducted. The discharge flow field is simulated using a gas-liquid turbulent flow model, and the vorticity fluctuation characteristics are then analyzed. The mathematical model for the LFN intensity is developed based on vortex sound theory and a turbulent flow model, verified by prototype observations. The model results reveal that the vorticity fluctuation in strong shear layers around the high-velocity submerged jets is highly correlated with the on-site LFN, and the strong shear layers are the main regions of acoustic source for the LFN. In addition, the predicted and observed magnitudes of LFN intensity agree quite well. This is the first time that the LFN intensity has been shown to be able to be predicted quantitatively.

  14. Insight into cordycepin biosynthesis of Cordyceps militaris: Comparison between a liquid surface culture and a submerged culture through transcriptomic analysis.

    Science.gov (United States)

    Suparmin, Ahmad; Kato, Tatsuya; Dohra, Hideo; Park, Enoch Y

    2017-01-01

    Cordyceps militaris produces cordycepin, which is known to be a bioactive compound. Currently, cordycepin hyperproduction of C. militaris was carried out in a liquid surface culture because of its low productivity in a submerged culture, however the reason was not known. In this study, 4.92 g/L of cordycepin was produced at the 15th day of C. militaris NBRC 103752 liquid surface culture, but only 1 mg/L was produced in the submerged culture. RNA-Seq was used to clarify the gene expression profiles of the cordycepin biosynthetic pathways of the submerged culture and the liquid surface culture. From this analysis, 1036 genes were shown to be upregulated and 557 genes were downregulated in the liquid surface culture compared with the submerged culture. Specifically, adenylosuccinate synthetase and phosphoribosylaminoimidazole-succinocarboxamide (SAICAR) synthase in purine nucleotide metabolism were significantly upregulated in the liquid surface culture. Thick mycelia formation in the liquid surface culture was found to induce the expression of hypoxia-related genes (GABA shunt, glutamate synthetase precursor, and succinate-semialdehyde dehydrogenase). Cytochrome P450 oxidoreductases containing heme were also found to be significantly enriched, suggesting that a hypoxic condition might be created in the liquid surface culture. These results suggest that hypoxic conditions are more suitable for cordycepin production in the liquid surface culture compared with the submerged culture. Our analysis paves the way for unraveling the cordycepin biosynthesis pathway and for improving cordycepin production in C. militaris.

  15. Mass Transfer Studies with Submerged Impinging Jets in Closed Cylindrical Electrolytic Cell in the Presence of Solids

    Directory of Open Access Journals (Sweden)

    S. Feroz

    2008-12-01

    Full Text Available An experimental study of mass transfer in forced convective flow of fluid electrolyte through submerged jets impinging normal to the target surface in a closed cylindrical cell in the presence of solids (Porcelain beads is reported. The pertinent dynamic and geometric variables of this study are flow rate, diameter of the nozzle, height of the nozzle from the target surface and solids fraction. The mass transfer measurements, made by the electrochemical method propose empirical correlations in the impingement and decreasing coefficient regions.

  16. Direct numerical simulation of three-dimensional liquid jet breakup

    Science.gov (United States)

    Constante, Ricardo; Kahouadji, Lyes; Nicolle, Andre; Chergui, Jalel; Juric, Damir; Shin, Seungwon; Matar, Omar K.

    2017-11-01

    We carry out direct numerical simulations of liquid jet dynamics and breakup using a high-performance code, Blue, which uses a hybrid technique based on the front-tracking and the level-set method; it defines the interface position through a marker function and a local triangular Lagrangian mesh. Liquid jet breakup is an example of interfacial complexity associated with multiphase flows because of the formation of ligaments and their pinch off to give rise to droplet formation. We consider the atomisation of a liquid jet released into a stagnant gas phase where the velocity is stimulated sinusoidally to promote the growth of Kelvin-Helmholtz instabilities, thus forming a flow system characterized by complex interfaces. The spread of cylindrical liquid jet into a coflowing external stream is also considered (essentially, a replication of the Marmottant and Villermaux experimental work). Funding from BP gratefully acknowledged.

  17. Stability of liquid-nitrogen-jet laser-plasma targets

    Science.gov (United States)

    Fogelqvist, E.; Kördel, M.; Selin, M.; Hertz, H. M.

    2015-11-01

    Microscopic jets of cryogenic substances such as liquid nitrogen are important regenerative high-density targets for high-repetition rate, high-brightness laser-plasma soft x-ray sources. When operated in vacuum such liquid jets exhibit several non-classical instabilities that negatively influence the x-ray source's spatial and temporal stability, yield, and brightness, parameters that all are important for applications such as water-window microscopy. In the present paper, we investigate liquid-nitrogen jets with a flash-illumination imaging system that allows for a quantitative stability analysis with high spatial and temporal resolution. Direct and indirect consequences of evaporation are identified as the key reasons for the observed instabilities. Operating the jets in an approximately 100 mbar ambient atmosphere counteracts the effects of evaporation and produces highly stable liquid nitrogen jets. For operation in vacuum, which is necessary for the laser plasmas, we improve the stability by introducing an external radiative heating element. The method significantly extends the distance from the nozzle that can be used for liquid-jet laser plasmas, which is of importance for high-average-power applications. Finally, we show that laser-plasma operation with the heating-element-stabilized jet shows improved short-term and long-term temporal stability in its water-window x-ray emission.

  18. Improving of Mixing by Submerged Rotary Jet (SRJ) System in a Large Industrial Storage Tank by CFD Techniques

    Science.gov (United States)

    Barekatain, H.; Hashemabadi, S. H.

    2011-09-01

    This paper reports the result of a CFD (Computational Fluid Dynamics) study on the Submerged Rotary Jet (SRJ) mixing system in a large industrial crude oil storage tank (one million barrels). This system has been installed on the tank just for reduction of sludge, but improper installation causes more accumulation of sludge on one side of tank. The main question is: How can we improve the mixing operation in this tank? For the purpose, a three dimensional modeling is carried out using an in-house CFD code and RNG k-ɛ model for turbulence prediction. The results show that pump suction location and crude oil velocity in tank are most effective factors on the sludge amount. Then, different ways such as increasing of jet flow rate, increasing and decreasing of tank height and reducing of nozzle diameter have been investigated. Finally, in this case, the results show the sedimentation of sludge in whole tank can be removed by 20% increasing of jet flow rate.

  19. Cryogenic grinding of electrospun poly-ε-caprolactone mesh submerged in liquid media.

    Science.gov (United States)

    Knotek, Petr; Pouzar, Miloslav; Buzgo, Matej; Krizkova, Barbora; Vlcek, Milan; Mickova, Andrea; Plencner, Martin; Navesnik, Jakub; Amler, Evzen; Belina, Petr

    2012-08-01

    In this paper, the treatment of poly-ε-caprolactone (PCL) nano/micro-mesh system by cryogenic grinding and subsequent characterization of obtained product is described. The PCL nano/micro-mesh layer submerged in appropriate liquid was cryogenically ground and obtained particles were characterized employing mainly laser diffraction and scanning electron microscopy (SEM). In the ground sample, different types of particles (fibrous particles, fibrous fragments, agglomerates with and without an internal fibrous structure, lamellae and nanoparticles) were identified, described and quantified. Parameters of cryogenic grinding (weight of sample, type of liquid medium, and influence of sample storage) were optimized to maximize the yield of particles with desired features. The potential of the system for cell scaffolding was demonstrated by cultivation of 3T3 fibroblasts on the produced microparticles. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Impinging jet separators for liquid metal magnetohydrodynamic power cycles

    Science.gov (United States)

    Bogdanoff, D. W.

    1973-01-01

    In many liquid metal MHD power, cycles, it is necessary to separate the phases of a high-speed liquid-gas flow. The usual method is to impinge the jet at a glancing angle against a solid surface. These surface separators achieve good separation of the two phases at a cost of a large velocity loss due to friction at the separator surface. This report deals with attempts to greatly reduce the friction loss by impinging two jets against each other. In the crude impinging jet separators tested to date, friction losses were greatly reduced, but the separation of the two phases was found to be much poorer than that achievable with surface separators. Analyses are presented which show many lines of attack (mainly changes in separator geometry) which should yield much better separation for impinging jet separators).

  1. Micrometer-thickness liquid sheet jets flowing in vacuum

    Science.gov (United States)

    Galinis, Gediminas; Strucka, Jergus; Barnard, Jonathan C. T.; Braun, Avi; Smith, Roland A.; Marangos, Jon P.

    2017-08-01

    Thin liquid sheet jet flows in vacuum provide a new platform for performing experiments in the liquid phase, for example X-ray spectroscopy. Micrometer thickness, high stability, and optical flatness are the key characteristics required for successful exploitation of these targets. A novel strategy for generating sheet jets in vacuum is presented in this article. Precision nozzles were designed and fabricated using high resolution (0.2 μm) 2-photon 3D printing and generated 1.49 ± 0.04 μm thickness, stable, and <λ /20-flat jets in isopropanol under normal atmosphere and under vacuum at 5 × 10-1 mbar. The thin sheet technology also holds great promise for advancing the fields of high harmonic generation in liquids, laser acceleration of ions as well as other fields requiring precision and high repetition rate targets.

  2. Efficiency of liquid-jet high-pressure booster compressors

    Science.gov (United States)

    Mikheev, N. I.; Davletshin, I. A.; Mikheev, A. N.; Kratirov, D. V.; Fafurin, V. A.

    2017-11-01

    There are almost no experimental data on the head-capacity curves for liquid-jet compressors with the inlet gas pressure of liquid-jet apparatus more than 1 MPa. Meanwhile, this range is important for many engineering applications in which relatively low compressor ratio is required for the pumping of gas under high pressure. This is mostly the case when gas circulation is to be provided in a closed or almost closed circuit. A head-capacity curve of a liquid-jet apparatus has been estimated experimentally for the air pumping at up to 2.5 MPa by a water jet. To obtain this curve, a new original technique has been submitted and verified which is based on an inverse unsteady problem of gas pumping and allows derivation of the whole curve instead of one operating point, which is the case for conventional methods. The experiments have demonstrated that the relative head of the liquid-jet compressor grows with the apparatus inlet air pressure in the middle part of the curve.

  3. Time-dependent variation of POF Bragg grating reflectivity and wavelength submerged in different liquids

    Science.gov (United States)

    Marques, C. A. F.; Pospori, A.; Webb, D. J.

    2017-09-01

    In this work, we investigate the time-dependent variation of both the reflectivity and resonance wavelength of microstructured polymer optical fiber Bragg grating (mPOFBG) array sensors embedded in silicone rubber and polyurethane resin diaphragms in contact with water and aircraft fuel, respectively. The array sensors were inscribed using two different phase masks with pitches of 557.5 and 580 nm and the thermal annealing of the inscribed fiber was used to change the Bragg wavelengths. Both the reflection and the resonance wavelength shift were monitored over 90 days submerged in liquid and two studies were investigated. In the first study, in addition to the mPOFBGs coated with the diaphragm, also the rest of the fiber is totally protected between the sensors with the same material used for diaphragms. On the other hand, in the second study, the fiber between sensors is unprotected - in direct contact with liquid. PMMA and TOPAS fibers were used and this study suggests that TOPAS fiber should be a good option for long-term liquid monitoring applications.

  4. Heat and mass transfer of submerged helium injection in liquid oxygen vessel

    Science.gov (United States)

    Jung, Youngsuk; Cho, Namkyung; Baek, Seungwhan; Jeong, Sangkwon

    2014-11-01

    The submerged helium injection process results in the heat and mass transfer between the helium bubble and the cryogenic liquid. The objective of this paper is to analyze the dynamics of the heat and mass transfer process. It is observed that during the helium injection process the dynamics of mass transfer is dominant and the transient heat transfer is negligible. The helium bubble shape and rising patterns are observed with a visualization device that helps to discern the dominant process between heat transfer and mass transfer. The clustering patterns such as coalescence of helium bubbles are observed with the visualization device. The visualization results indicate that, it is very difficult to determine the representative size of bubbles due to the irregular shape of the helium bubbles. The shape and size of the helium bubbles are important parameters for evaluating the overall mass transfer coefficient (kGA) which is the essential parameter for calculating the evaporation rate of the bulk liquid into the helium bubbles. In this paper, the simplified lumped model is considered to fairly approximate the evaporation rate of the cryogenic liquid into the bubbles and the cooling rate of helium injection. The empirical correlation for the average concentration (C‾A) of evaporated cryogenic liquid into the helium bubbles is presented and the overall mass transfer coefficients (kGA) are calculated as the result of the lumped model. The proposed model and empirical correlations are compared with the experimental results, and the comparison result shows good agreement with differences that are less than ±0.4 K.

  5. COMPARATIVE EVALUTION OF CEPHALOSPORIN-C PRODUCTION IN SOLID STATE FERMENTATION AND SUBMERGED LIQUID CULTURE

    Directory of Open Access Journals (Sweden)

    Mahdi Rezazarandi

    2012-08-01

    Full Text Available The advantages of solid state fermentation (SSF utilization in producing enzymes & secondary metabolites have been shown, whereas, submerged liquid fermentation (SLF condition has the major usage in industrial production of antibiotics. As an antibiotic of B-lactams group, cephalosporin-C (CPC is indicated due to its wide effect and broad convention in treatment of infectious diseases. Regarding industrial production of CPC regularly done in SLF condition, we compared CPC production sum in SLF and SSF conditions. In this analysis, A. chrysogenum was employed, which was inoculated to SLF and SSF, while internal fermenter conditions were totally under control. After extraction of CPC, productions in two states of SLF and SSF were compared using the cylinder plate method. According to Antibiotic assay and production amount comparison, results expressed a ratio of development of production in SSF conditions to SLF conditions. Regarding previous studies on a solid state fermenter and its advantages, in this study, convenience of SSF conditions compared to SLF conditions was experimented. Also mentioning that maintaining the condition of solid state fermenter is more comfortable and practical than liquid state fermenter, using a solid based fermenter to produce antibiotics, especially CPC, can be appropriate. Considering appropriate control conditions of SSF to produce secondary metabolites, decrease in expenses, and increase of production, taking advantage of it in order to increase production parallel to modern methods, such as genetically manipulating CPC producing microorganisms are recommended to pharmacological industries. Also, to make this method applicable, further studies in industrial criterion seem necessary.

  6. Liquid jets injected into non-uniform crossflow

    Science.gov (United States)

    Tambe, Samir

    An experimental study has been conducted with liquid jets injected transversely into a crossflow to study the effect of non-uniformities in the crossflow velocity distribution to the jet behavior. Two different non-uniform crossflows were created during this work, a shear-laden crossflow and a swirling crossflow. The shear-laden crossflow was generated by merging two independent, co-directional, parallel airstreams creating a shear mixing layer at the interface between them. The crossflow exhibited a quasi-linear velocity gradient across the height of the test chamber. By varying the velocities of the two airstreams, the sense and the slope of the crossflow velocity gradient could be changed. Particle Image Velocimetry (PIV) studies were conducted to characterize the crossflow. The parameter, UR, is defined as the ratio of the velocities of the two streams and governs the velocity gradient. A positive velocity gradient was observed for UR > 1 and a negative velocity gradient for UR 1), jet penetration increased and the Sauter Mean Diameter (SMD) distribution became more uniform. For low UR (designed axial swirlers. Three swirlers were used, with vane exit angles of 30°, 45° and 60°. Laser Doppler Velocimetry (LDV) was used to study the crossflow velocities. The axial (Ux) and the tangential (Utheta) components of the crossflow velocity were observed to decrease with increasing radial distance away from the centerbody. The flow angle of the crossflow was smaller than the vane exit angle, with the difference increasing with the vane exit angle. Water jets were injected from a 0.5 mm diameter orifice located on a cylindrical centerbody. Multi-plane PIV measurements were conducted to study the penetration and droplet velocity distribution of the jets. The jets were observed to follow a path close to the helical trajectory of the crossflow with a flow angle slightly less than the crossflow. This deficit in flow angle is attributed to the centrifugal acceleration

  7. Structure of the Continuous Liquid Jet Core during Coaxial Air-Blast Atomisation

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    Georgios Charalampous

    2009-12-01

    Full Text Available This paper investigates the structure of the continuous liquid jet of a coaxial air-blast atomiser over a range of Weber numbers 60-1040, Reynolds numbers of liquid jet 5400-21700 and air to liquid momentum ratios of the two streams of 1.7–335. A novel optical technique, based on internal illumination of the liquid jet through the jet nozzle by a laser pulse, which excites a fluorescing dye introduced in the atomizing liquid, was used to obtain instantaneous measurements of the breakup length and the three dimensional location of the liquid core of the continuous liquid jet. The latter was achieved by simultaneously imaging the liquid jet from two directions normal to each other. Such measurements are usually prevented by droplets surrounding the liquid jet at the dense spray near the nozzle exit. The measurements showed that the break-up length of the liquid jet scaled well with the air to liquid momentum ratio. The standard deviation of the temporal fluctuations of the break-up length was around 10% of the mean breakup length for each considered flow condition. The instantaneous jet surface does not develop axi-symmetric wave structures but the time-averaged liquid jet is axi-symmetric around the nozzle axis, while the maximum deflection of the liquid jet occurs close to the breaking point.

  8. Liquid Jet Formation in Laser-Induced Forward Transfer

    Science.gov (United States)

    Brasz, C. Frederik

    Laser-induced forward transfer (LIFT) is a direct-write technique capable of printing precise patterns of a wide variety of materials. In this process, a laser pulse is focused through a transparent support and absorbed in a thin donor film, propelling material onto an adjacent acceptor substrate. For fluid materials, this transfer occurs through the formation of a narrow liquid jet, which eventually pinches off due to surface tension. This thesis examines in detail the fluid mechanics of the jet formation process occurring in LIFT. The main focus is on a variant of LIFT known as blister-actuated LIFT (BA-LIFT), in which the laser pulse is absorbed in an ink-coated polymer layer, rapidly deforming it locally into a blister to induce liquid jet formation. The early-time response of a fluid layer to a deforming boundary is analyzed with a domain perturbation method and potential-flow simulations, revealing scalings for energy and momentum transfer to the fluid and providing physical insight on how and why a jet forms in BA-LIFT. The remaining chapters explore more complex applications and modifications of LIFT. One is the possibility of high-repetition rate printing and limits on time delay and separation between pulses imposed by a tilting effect found for adjacent jets. Another examines a focusing effect achieved by perturbing the interface with ring-shaped disturbances. The third contains an experimental study of LIFT using a silver paste as the donor material instead of a Newtonian liquid. The transfer mechanism is significantly different, although with repeated pulses at one location, a focusing effect is again observed. All three of these chapters investigate how perturbations to the interface can strongly influence the jet formation process.

  9. Innovation Incubator: LiquidCool Solutions Technical Evaluation. Laboratory Study and Demonstration Results of a Directed-Flow, Liquid Submerged Server for High-Efficiency Data Centers

    Energy Technology Data Exchange (ETDEWEB)

    Kozubal, Eric J [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-12-12

    LiquidCool Solutions (LCS) has developed liquid submerged server (LSS) technology that changes the way computer electronics are cooled. The technology provides an option to cool electronics by the direct contact flow of dielectric fluid (coolant) into a sealed enclosure housing all the electronics of a single server. The intimate dielectric fluid contact with electronics improves the effectiveness of heat removal from the electronics.

  10. Jet-noise reduction through liquid-base foam injection.

    Science.gov (United States)

    Manson, L.; Burge, H. L.

    1971-01-01

    An experimental investigation has been made of the sound-absorbing properties of liquid-base foams and of their ability to reduce jet noise. Protein, detergent, and polymer foaming agents were used in water solutions. A method of foam generation was developed to permit systematic variation of the foam density. The investigation included measurements of sound-absorption coefficents for both plane normal incidence waves and diffuse sound fields. The intrinsic acoustic properties of foam, e.g., the characteristic impedance and the propagation constant, were also determined. The sound emitted by a 1-in.-diam cold nitrogen jet was measured for subsonic (300 m/sec) and supersonic (422 m/sec) jets, with and without foam injection. Noise reductions up to 10 PNdB were measured.

  11. Combined aerodynamic and electrostatic atomization of dielectric liquid jets

    Energy Technology Data Exchange (ETDEWEB)

    Kourmatzis, Agissilaos [University of Sydney, Clean Combustion Research Group, Aerospace, Mechanical and Mechatronic Engineering, Sydney, NSW (Australia); Ergene, Egemen L.; Mashayek, Farzad [University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, Chicago, IL (United States); Shrimpton, John S. [University of Southampton, Energy Technology Research Group, School of Engineering Sciences, Southampton (United Kingdom); Kyritsis, Dimitrios C.; Huo, Ming [University of Illinois at Urbana-Champaign, Department of Mechanical Science and Engineering, Urbana, IL (United States)

    2012-07-15

    The electrical and atomization performance of a plane-plane charge injection atomizer using a dielectric liquid, and operating at pump pressures ranging from 15 to 35 bar corresponding to injection velocities of up to 50 m/s, is explored via low current electrical measurements, spray imaging and phase Doppler anemometry. The work is aimed at understanding the contribution of electrostatic charging relevant to typical higher pressure fuel injection systems such as those employed in the aeronautical, automotive and marine sectors. Results show that mean-specific charge increases with injection velocity significantly. The effect of electrostatic charge is advantageous at the 15-35 bar range, and an arithmetic mean diameter D{sub 10} as low as 0.2d is achievable in the spray core and lower still in the periphery where d is the orifice diameter. Using the data available from this higher pressure system and from previous high Reynolds number systems (Shrimpton and Yule Exp Fluids 26:460-469, 1999), the promotion of primary atomization has been analysed by examining the effect that charge has on liquid jet surface and liquid jet bulk instability. The results suggest that for the low charge density Q{sub v}{proportional_to} 2 C/m{sup 3} cases under consideration here, a significant increase in primary atomization is observed due to a combination of electrical and aerodynamic forces acting on the jet surface, attributed to the significantly higher jet Weber number (We{sub j}) when compared to low injection pressure cases. Analysis of Sauter mean diameter results shows that for jets with elevated specific charge density of the order Q{sub v}{proportional_to} 6 C/m{sup 3}, the jet creates droplets that a conventional turbulent jet would, but with a significantly lower power requirement. This suggests that 'turbulent' primary atomization, the turbulence being induced by electrical forces, may be achieved under injection pressures that would produce laminar jets

  12. Integrated liquid jet waveguide for fluorescence spectroscopy on chip

    Science.gov (United States)

    Persichetti, Gianluca; Testa, Genni; Bernini, Romeo

    2013-03-01

    An optofluidic jet waveguide for on chip fluorescence analysis is presented. The waveguide consists of an high speed water jet produced by means of a micro-channel coupled with a multimode optical fiber collecting the fluorescence opportunely excited. The liquid jet acts, at the same time, as the solution to analyse and as an optical waveguide. This configuration allows a strong reduction of the scattering and fluorescence of non analyte substances enabling a very low limit of detection (LOD). The integrated device is fabricated by PMMA micro-machining allowing a self-alignment between the liquid jet waveguide and the optical fiber used to deliver the fluorescence to the detector. The performance of the system has been tested on Cy5 water solutions and LOD of 2.56 nM has been obtained. A proof-of-concept of filter-free measurements has been performed demonstrating that fluorescence measurements can be performed also by using a photodiode with an LOD of 6.11 nM.

  13. The liquid micro-jet from laser induced cavitation bubbles.

    Science.gov (United States)

    Abboud, Jack; Oweis, Ghanem

    2007-11-01

    A vaporous cavitation bubble grows spherically in an infinite medium to a maximum radius, collapses in a spherical manner to a minimum volume, and then may rebound one or more times or disintegrate. When the bubble collapses above a solid boundary, the asymmetry of the surrounding flow field will cause the upper bubble surface to cave in, resulting in a fast liquid jet that penetrates its lower surface and continues towards the solid boundary. This fast jet formation is one perceived mechanism for cavitation damage in hydro-machinery. If a hole is intentionally drilled in the solid boundary underneath the collapsing bubble, the fast micro-jet can continue its path and be cultivated for a variety of applications such as micro surgery of soft tissue. In this study, cavitation bubbles are generated by focusing the pulsed IR beam from an Nd-YAG laser above a solid surface. The forming liquid micro-jet is investigated in the cases of blank and drilled solid boundaries.

  14. Restraint of Liquid Jets by Surface Tension in Microgravity Modeled

    Science.gov (United States)

    Chato, David J.

    2001-01-01

    Tension in Microgravity Modeled Microgravity poses many challenges to the designer of spacecraft tanks. Chief among these are the lack of phase separation and the need to supply vapor-free liquid or liquidfree vapor to the spacecraft processes that require fluid. One of the principal problems of phase separation is the creation of liquid jets. A jet can be created by liquid filling, settling of the fluid to one end of the tank, or even closing a valve to stop the liquid flow. Anyone who has seen a fountain knows that jets occur in normal gravity also. However, in normal gravity, the gravity controls and restricts the jet flow. In microgravity, with gravity largely absent, jets must be contained by surface tension forces. Recent NASA experiments in microgravity (Tank Pressure Control Experiment, TPCE, and Vented Tank Pressure Experiment, VTRE) resulted in a wealth of data about jet behavior in microgravity. VTRE was surprising in that, although it contained a complex geometry of baffles and vanes, the limit on liquid inflow was the emergence of a liquid jet from the top of the vane structure. Clearly understanding the restraint of liquid jets by surface tension is key to managing fluids in low gravity. To model this phenomenon, we need a numerical method that can track the fluid motion and the surface tension forces. The fluid motion is modeled with the Navier-Stokes equation formulated for low-speed incompressible flows. The quantities of velocity and pressure are placed on a staggered grid, with velocity being tracked at cell faces and pressure at cell centers. The free surface is tracked via the introduction of a color function that tracks liquid as 1/2 and gas as -1/2. A phase model developed by Jacqmin is used. This model converts the discrete surface tension force into a barrier function that peaks at the free surface and decays rapidly. Previous attempts at this formulation have been criticized for smearing the interface. However, by sharpening the phase

  15. Lattice Boltzmann modeling and simulation of liquid jet breakup

    Science.gov (United States)

    Saito, Shimpei; Abe, Yutaka; Koyama, Kazuya

    2017-07-01

    A three-dimensional color-fluid lattice Boltzmann model for immiscible two-phase flows is developed in the framework of a three-dimensional 27-velocity (D3Q27) lattice. The collision operator comprises the D3Q27 versions of three suboperators: a multiple-relaxation-time (MRT) collision operator, a generalized Liu-Valocchi-Kang perturbation operator, and a Latva-Kokko-Rothman recoloring operator. A D3Q27 version of an enhanced equilibrium distribution function is also incorporated into this model to improve the Galilean invariance. Three types of numerical tests, namely, a static droplet, an oscillating droplet, and the Rayleigh-Taylor instability, show a good agreement with analytical solutions and numerical simulations. Following these numerical tests, this model is applied to liquid-jet-breakup simulations. The simulation conditions are matched to the conditions of the previous experiments. In this case, numerical stability is maintained throughout the simulation, although the kinematic viscosity for the continuous phase is set as low as 1.8 ×10-4 , in which case the corresponding Reynolds number is 3.4 ×103 ; the developed lattice Boltzmann model based on the D3Q27 lattice enables us to perform the simulation with parameters directly matched to the experiments. The jet's liquid column transitions from an asymmetrical to an axisymmetrical shape, and entrainment occurs from the side of the jet. The measured time history of the jet's leading-edge position shows a good agreement with the experiments. Finally, the reproducibility of the regime map for liquid-liquid systems is assessed. The present lattice Boltzmann simulations well reproduce the characteristics of predicted regimes, including varicose breakup, sinuous breakup, and atomization.

  16. Formation of liquid chain by collision of two laminar jets

    Science.gov (United States)

    Sanjay, Vatsal; Das, Arup Kumar

    2017-11-01

    The collision of liquid jets and formation of a sheet in the median plane are illustrated numerically. The sheet subsequently transforms into a chain-like fluidic structure with successive dwarf links in mutually orthogonal planes. To understand the behavior of fluid parcels inside the chain, flow kinematics are studied with streamlines and a self-similar velocity profile. For the generalization of chain profiles over a wide range of operating parameters, a correlation has been proposed based on numerical simulations and subsequent regression analyses. Citing the analogy between the impact of jets for the formation of elemental links and traversal of non-deformable fluid quanta after the collision, an attempt has been made to understand the fundamental physics of this phenomenon through force balance. The analogy helps us to take into account the role of surface tension and other forces on the shape and size of the liquid sheets. Further, the formation of higher order links is proposed as equivalent to the collision between the liquid rims bounding the sheet, modeled as the jets of reduced strengths and smaller impingement angles. Finally, we assess the effects of various fluid properties on the dimensions of these links, illustrating the viscous dissipation at the time of collisions.

  17. Jet impingement and primary atomization of non-Newtonian liquids

    Science.gov (United States)

    Mallory, Jennifer A.

    The effect of liquid rheology on the flowfield resulting from non-Newtonian impinging jets was investigated experimentally and analytically. Experimental data were acquired using a unique experimental apparatus developed to examine the jet impingement of non-Newtonian liquids. The analytical modeling was aimed at determining which physical mechanisms transform non-Newtonian impinging jets into a sheet with waves on its surface, how those waves influence sheet fragmentation and subsequent ligament formation, and how those ligaments break up to form drops (primary atomization). Prior to impinging jet measurements, the rheological properties of 0.5 wt.-% CMC-7HF, 1.4 wt.-% CMC-7MF, 0.8 wt.-% CMC-7MF, 0.06 wt.-% CMC-7MF 75 wt.-% glycerin, 1 wt.-% Kappa carrageenan, and 1 wt.-% Agar were determined through the use of rotational and capillary rheometers. Two approaches were used to experimentally measure solid-like gel propellant simulant static surface tension. All liquids exhibited pseudoplastic rheological behavior. At various atomizer geometric and flow parameters sheet instability wavelength, sheet breakup length, ligament diameter, and drop sizes were measured from high-speed video images. Results showed that viscosity dependence on shear rate is not the sole factor that determines atomization likelihood. Instead, a key role is played by the interaction of the gelling agent with the solvent at the molecular level. For instance, despite high jet exit velocities and varying atomizer geometric parameters HPC gel propellant simulants did not atomize. The molecular nature of HPC results in physical entanglement of polymer chains when gelled, which resists liquid breakup and subsequent spray formation. However, atomization was achieved with Agar, which absorbs the water and forms a network around it rather than bonding to it. The measured liquid sheet instability wavelength, sheet breakup length, ligament diameter, and drop sizes were compared to predictions from a

  18. Nanoparticle-wall collision in a laminar cylindrical liquid jet.

    Science.gov (United States)

    Xu, Xuefeng; Luo, Jianbin; Guo, Dan

    2011-07-15

    Although nanoparticle impacts on a solid surface always occur in natural or engineering processes and cause extensive investigations, less works have been reported on the nanoparticle-wall collisions in a liquid. In present paper, by considering the inertial effect and the Brownian motion of nanoparticles, a theoretical model was established for calculating the collision frequency between the nanoparticles and the solid surface in a laminar cylindrical liquid jet impacting normally on the solid surface. The analysis showed that the collision frequency grows as the square root of the impacting speed for low impacting speed regime in which the Brownian motion is predominant, whereas increases as the second power of the impacting speed for high impacting speed regime in which the inertial effect is predominant. Meanwhile, an observation system for nanoparticle-wall collisions in a laminar cylindrical liquid jet has been developed. The adsorption of the nanoparticles on the solid surface after collision has also been observed. Because of their lower attractive energy with the solid surface, these adsorbed nanoparticles are easier to be removed by the hydrodynamic force of the impacting liquid than that deposited on a dry surface. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Jet-mixing of initially-stratified liquid-liquid pipe flows: experiments and numerical simulations

    Science.gov (United States)

    Wright, Stuart; Ibarra-Hernandes, Roberto; Xie, Zhihua; Markides, Christos; Matar, Omar

    2016-11-01

    Low pipeline velocities lead to stratification and so-called 'phase slip' in horizontal liquid-liquid flows due to differences in liquid densities and viscosities. Stratified flows have no suitable single point for sampling, from which average phase properties (e.g. fractions) can be established. Inline mixing, achieved by static mixers or jets in cross-flow (JICF), is often used to overcome liquid-liquid stratification by establishing unstable two-phase dispersions for sampling. Achieving dispersions in liquid-liquid pipeline flows using JICF is the subject of this experimental and modelling work. The experimental facility involves a matched refractive index liquid-liquid-solid system, featuring an ETFE test section, and experimental liquids which are silicone oil and a 51-wt% glycerol solution. The matching then allows the dispersed fluid phase fractions and velocity fields to be established through advanced optical techniques, namely PLIF (for phase) and PTV or PIV (for velocity fields). CFD codes using the volume of a fluid (VOF) method are then used to demonstrate JICF breakup and dispersion in stratified pipeline flows. A number of simple jet configurations are described and their dispersion effectiveness is compared with the experimental results. Funding from Cameron for Ph.D. studentship (SW) gratefully acknowledged.

  20. Experiments on annular liquid jet instability and on the formation of liquid shells

    Science.gov (United States)

    Kendall, J. M.

    1986-01-01

    An annular jet flow of liquid surrounding a flow of gas at its core is extremely unstable. Experiments are described in which such a flow is generated by an annular nozzle operated at fairly specific conditions. It is shown that periodic, axisymmetric oscillations arise spontaneously within the cylindrical sheet emerging from the nozzle and grow with such rapidity along the axial dimension that a sealing-off and encapsulation of the core gas occurs within a few jet diameters. This is closely followed by a pinchoff of the liquid between adjacent bubbles. The liquid shells set free thereby assume spherically symmetric form under capillary forces, and each contains a precisely uniform measure of gas and of liquid on account of the extremely high frequency-stability of the process. Description is given of the fluid dynamic processes by which the shells are formed, and mention is made of exploiting the instability for the production of rigid shells for technological applications.

  1. Shape and stability in liquid threads and jets : a link to droplet formation

    NARCIS (Netherlands)

    Heugten, van W.G.N.

    2015-01-01

    This thesis explores relevant fluid dynamic processes for the formation of uniformly sized droplets in microfluidic systems. Growing droplets made from a bulk source have often liquid threads or jets in between to supply liquid to the droplet. Liquid threads and jets are however known to be instable

  2. Novel Laser-Based Technique for Measurements of Primary Atomization Characteristics of Liquid Jets

    Science.gov (United States)

    2012-08-22

    air velocity. The swirling air flow component will be generated by introducing the air flow in the upstream pipe through tangential air inlets...Discussion 11 (a) Geometrical Optics calculations 11 (b) Design of experimental facility of liquid jet in a cross stream of swirling air flow 14...unique, because it allows swirling air flow to interact with the injected liquid jet. No measurements are available of the behaviour of liquid jets

  3. Impinging jet spray formation using non-Newtonian liquids

    Science.gov (United States)

    Rodrigues, Neil S.

    Over the past two decades there has been a heightened interest in implementing gelled propellants for rocket propulsion, especially for hypergolic bi-propellants such as monomethylhydrazine (MMH) and nitrogen tetroxide oxidizer (NTO). Due to the very high level of toxicity of hypergolic liquid rocket propellants, increasing safety is an important area of need for continued space exploration and defense operations. Gelled propellants provide an attractive solution to meeting the requirements for safety, while also potentially improving performance. A gelling agent can be added to liquid propellants exhibiting Newtonian behavior to transform the liquid into a non-Newtonian fluid with some solid-like behavior, i.e. a gel. Non-Newtonian jet impingement is very different from its Newtonian counterpart in terms of fluid flow, atomization, and combustion. This is due to the added agents changing physical properties such as the bulk rheology (viscosity) and interfacial rheology (surface tension). Spray characterization of jet impingement with Newtonian liquids has been studied extensively in existing literature. However, there is a scarcity in literature of studies that consider the spray characterization of jet impingement with gelled propellants. This is a rather critical void since a major tradeoff of utilizing gelled propellants is the difficulty with atomization due to the increased effective viscosity. However, this difficulty can be overcome by using gels that exhibit shear-thinning behavior---viscosity decreases with increasing strain rate. Shear-thinning fluids are ideal because they have the distinct advantage of only flowing easily upon pressure. Thereby, greatly reducing the amount of propellant that could be accidentally leaked during both critical functions such as liftoff or engagement in the battlefield and regular tasks like refilling propellant tanks. This experimental work seeks to help resolve the scarcity in existing literature by providing drop size

  4. Experimental and theoretical studies of vertical annular liquid jets

    Science.gov (United States)

    Chigier, Norman; Ramos, J. I.; Kihm, K. D.

    1988-05-01

    The objectives of this study are to determine the stability, dynamics, and convergence of vertical annular liquid jets as a function of the initial radius, sheet thickness, and velocity. The influence of variation of Froude, Reynolds, and Weber numbers and geometry on convergence and stability are examined. An implicit finite-difference scheme is developed for solution of the steady-state and time-dependent axisymmetric Navier-Stokes equations. In collaboration with Westinghouse, a cylindrical film chemical reactor will be designed for control of reactions such as reduction of zirconium. Annular liquid curtains have been formed with an initial curtain radius of 50 mm and initial sheet thicknesses of 0.5 and 1.0 mm. Three Froude numbers have been studied: 1.27, 4.27, and 8.87 with variation of the liquid flow rate. Pressure within the curtains has been varied progressively from 0 to 3 Pa. Several flow regimes were found: (1) non-pressurized, (2) pressurized, (3) oscillating, and (4) punctured. Curtain shape and convergence length were determined for each condition by photography. Axial mean velocity in the liquid curtain was measured by Laser Doppler Anemometry along the length of the curtain. The variation of liquid film thickness with axial distance was determined.

  5. Effect of nozzle length-to-diameter ratio on atomization of turbulent liquid jets

    Science.gov (United States)

    Osta, Anu Ranjan

    Breakup of liquid jets is of considerable interest motivated by its applicability in combustion and propulsion systems (CI and SI engines), and agricultural fertilizer/pesticide sprays, among others. Almost all of the practical liquid injectors introduce some degree of turbulence in the liquid jet leaving the injector passage and an intriguing question is the relative importance of the liquid turbulence, cavitation, and the aerodynamic forces in the breakup processes of fuel injectors. A better design of liquid fuel injector would reduce pollutants and increase the efficiency of liquid fuel combustion processes. An experimental study to investigate the effect of nozzle length to diameter ratio on the surface properties of turbulent liquid jets in gaseous crossflow and still air was carried out. Straight cavitation-free nozzles with length/diameter ratios of 10, 20 and 40 were used to generate turbulent liquid jets in gaseous crossflow. The present study was limited to small Ohnesorge number liquid jets (Oh 110). The diagnostics consisted of pulsed shadowgraphy, pulsed digital holographic microscopy and x-ray diagnostics. The x-ray tests were conducted at the Advanced Photon Source (APS) facility of Argonne National Laboratory. The test matrix was designed to maintain the same aerodynamic forces in order to isolate the effects of jet turbulence on the breakup process. The measurements included liquid jet surface properties, breakup location of the liquid column as a whole, the breakup regime transitions, bubble size inside the jet and seeding particle displacement inside the jet structures. The results include the jet surface characteristics, the liquid column breakup lengths, bubble growth, and phenomenological analysis to explain the observed results. It is observed that for a jet breakup in crossflow the injector passage length does play a role in determining the breakup length as well as influence the characteristics of the jet upwind surface. The present

  6. Experimental Study of Ignition over Impact-Driven Supersonic Liquid Fuel Jet

    Directory of Open Access Journals (Sweden)

    Anirut Matthujak

    2013-01-01

    Full Text Available This study experimentally investigates the mechanism of the ignition of the supersonic liquid fuel jet by the visualization. N-Hexadecane having the cetane number of 100 was used as a liquid for the jet in order to enhance the ignition potential of the liquid fuel jet. Moreover, the heat column and the high intensity CO2 laser were applied to initiate the ignition. The ignition over the liquid fuel jet was visualized by a high-speed digital video camera with a shadowgraph system. From the shadowgraph images, the autoignition or ignition of the supersonic liquid fuel jet, at the velocity of 1,186 m/s which is a Mach number relative to the air of 3.41, did not take place. The ignition still did not occur, even though the heat column or the high intensity CO2 laser was alone applied. The attempt to initiate the ignition over the liquid fuel jet was achieved by applying both the heat column and the high intensity CO2 laser. Observing the signs of luminous spots or flames in the shadowgraph would readily indicate the presence of ignitions. The mechanism of the ignition and combustion over the liquid fuel jet was clearly clarified. Moreover, it was found that the ignition over the supersonic liquid fuel jet in this study was rather the force ignition than being the auto-ignition induced by shock wave heating.

  7. Novel Techniques for Quantification of Correlation Between Primary Liquid Jet Breakup and Downstream Spray Characteristics

    Science.gov (United States)

    2016-10-05

    unlimited. 5 1. Introduction Several liquid -fuelled combustion systems, such as liquid propellant rocket engines and gas turbines... liquid sheet[1], [2], [3]. Considering the challenges in studying spray combustion due to interacting complex physical and chemical processes...AFRL-AFOSR-JP-TR-2016-0084 Novel techniques for quantification of correlation between primary liquid jet breakup and downstream spray characteristics

  8. Behavior of cylindrical liquid jets evolving in a transverse acoustic field

    Science.gov (United States)

    Carpentier, Jean-Baptiste; Baillot, Françoise; Blaisot, Jean-Bernard; Dumouchel, Christophe

    2009-02-01

    This paper presents a theoretical and an experimental investigation of low-velocity cylindrical liquid jets submitted to transverse planar acoustic waves. For this purpose, the behavior of a liquid jet traversing the section of a Kundt tube was examined. Experiments reported that the liquid jet could be either deviated from its trajectory or deformed as a succession of lobes oriented in space and whose length and width depend on the jet acoustic environment. Furthermore, for a sufficient acoustic velocity, the jet deformation increases in such proportion that a premature and vivid atomization mechanism disintegrates the liquid flow. Theoretical models are proposed to understand these behaviors. The first one calls out for acoustic radiation pressure to explain the jet deviation. The second one consists in a modal analysis of the vibrations of a jet when submitted to a transverse stationary acoustic field. As a first approach, a simplified two-dimensional model is proposed. This model reports that a sudden exposition of the jet to an acoustic field triggers two jet eigenmodes. One of them induces jet deformations that were not experimentally observed. This part of the solution emerges due to theoretical deficiencies. However, the second mode reproduces the lobe formation and leads to atomization criteria in good agreement with the experimental results. The paper ends with an extension of the mathematical development in three dimensions in order to provide a basis to a more consistent model.

  9. Mixing liquid-liquid stratified flows using transverse jets in cross flows

    Science.gov (United States)

    Wright, Stuart; Matar, Omar K.; Markides, Christos N.

    2017-11-01

    Low pipeline velocities in horizontal liquid-liquid flows lead to gravitationally-induced stratification. This results in flow situations that have no point where average properties can be measured. Inline mixing limits the stratification effect by forming unstable liquid-liquid dispersions. An experimental system is used to measure the mixing performance of various jet-in-cross-flow (JICF) configurations as examples of active inline mixers. The test section consists of a 8.5-m long ETFE pipe with a 50-mm diameter, which is refractive index-matched to both a 10 cSt silicone oil and a 51 wt% glycerol solution. This practice allows advanced laser-based optical techniques, namely PLIF and PIV/PTV, to be applied to these flows in order to measure the phase fractions and velocity fields, respectively. A volume of a fluid (VOF) CFD code is then used to simulate simple jet geometries and to demonstrate the breakup and dispersion capabilities of JICFs in stratified pipeline flows by predicting their mixing efficiency. These simulation results are contrasted with the experimental results to examine the effectiveness of these simulations in predicting the dispersion and breakup. Funding from Cameron/Schlumberger, and the TMF Consortium gratefully acknowledged.

  10. A Review on Empirical Correlations for Jet/Spray Trajectory of Liquid Jet in Uniform Cross Flow

    Directory of Open Access Journals (Sweden)

    Soo-Young No

    2015-12-01

    Full Text Available The empirical correlations for the prediction of jet/spray penetration of liquid jet in subsonic uniform crossflow are reviewed in this study. Considerable number of empirical correlations had been proposed by many investigators. It has generally known that the jet/spray trajectory of a liquid jet in a cross-flow is a function of the liquid to air momentum flux ratio and the normalized distance in the airstream direction from the injector. However, several researchers incorporated the Weber number, liquid-to-water or air viscosity ratio, pressure ratio or Reynolds number, temperature ratio in the empirical correlations. Two different classification methods of correlations, i.e. classification based on mathematic functional form and classification based on flow regime, are introduced in this study. The one classification of existing correlations based on functional form includes correlations in a power-law, logarithmic, and exponential forms, respectively. The other classification of previous correlations based on flow regime includes one, two and three regime, correlations. Correlations in a power-law functional form can be further divided into three groups such as momentum flux ratio, Weber number and other parameters forms. Correlations in logarithmic functional form can be also grouped as momentum flux ratio and Weber number forms. Most of the evaluation studies reported the significant discrepancies of predicted values by the existing correlations. The possible reasons for discrepancies will be summarized as measurement technique, assumptions made in defining terms in the liquid to air momentum flux ratio, difficulties in defining the boundaries of the liquid jets, turbulence level in the core and boundary layer of incoming jet and gas flows, nozzle/injector geometry and its position in the crossflow. However, it can be found from the several evaluation studies that the power-law functional form with momentum flux ratio and two regimes

  11. Thinning and rupture of liquid films by moving slot jets.

    Science.gov (United States)

    Berendsen, Christian W J; Zeegers, Jos C H; Darhuber, Anton A

    2013-12-23

    We present systematic experiments of the rupture and dewetting of thin films of a nonvolatile polar liquid on partially wetting substrates due to a moving slot jet, which impinges at normal incidence. The relative motion was provided by a custom-built spin coater with a bidirectionally accessible axis of rotation that enabled us to measure film thickness profiles in situ as a function of substrate velocity using dual-wavelength interference microscopy. On partially wetting polymeric substrates, dry spots form in liquid films with a residual thickness well below 1 μm. We measured the density of dry spots as well as the density and size distribution of the residual droplets as a function of film thickness. In a certain parameter range, the droplet distributions exhibit pronounced anisotropy due to the effect of long-range shear stresses on the dewetting rim instability. We find robust power-law scaling relations over a large range of film thicknesses and a striking similarity to literature data obtained with ultrathin polymer melt layers on silicon substrates.

  12. Liquid culture production of microsclerotia and submerged conidia by Trichoderma harzianum active against damping-off disease caused by Rhizoctonia solani.

    Science.gov (United States)

    Kobori, Nilce N; Mascarin, Gabriel M; Jackson, Mark A; Schisler, David A

    2015-04-01

    Media and culturing protocols were identified that supported the formation of submerged conidia and microsclerotia (MS) by Trichoderma harzianum Rifai strain T-22 using liquid culture fermentation. Liquid media with a higher carbon concentration (36 g L(-1)) promoted MS formation at all C:N ratios tested. Hyphae aggregated to form MS after 2 d growth and after 7 d MS were fully melanized. This is the first report of MS formation by T. harzianum or any species of Trichoderma. Furthermore, submerged conidia formation was induced by liquid culture media, but yields, desiccation tolerance, and storage stability varied with C:N ratio and carbon rate. Air-dried MS granules (harzianum as a potential biofungicide for use in integrated management programs against soilborne diseases. Copyright © 2014 The British Mycological Society. All rights reserved.

  13. Splashing liquid drops form vortex rings and not jets at low Froude numbers

    Science.gov (United States)

    Carroll, Kenneth; Mesler, Russell

    1981-01-01

    Colored drops falling only a short distance into clear liquid form vortex rings. A numerical study using the Marker and Cell technique predicted instead a jet rising from the cavity formed by the impact.

  14. Analysis of heat transfer for a normally impinging liquid-metal slot jet

    Science.gov (United States)

    Siegel, R.

    1973-01-01

    A two-dimensional liquid-metal slot jet that is impinging normally against a uniformly heated flat plate is analyzed. The distributions of wall temperature and heat-transfer coefficient are obtained as functions of position along the plate. The liquid-metal assumptions are made that the jet is inviscid and that molecular condition is dominating heat diffusion. The solution is obtained by mapping the jet flow region into a potential plane where it occupies a strip of uniform width. The energy equation is transformed into potential coordinates, and an exact solution obtained in the strip region. Conformal mapping is then used to transform the solution into the physical plane.

  15. Analysis of liquid-metal-jet impingement cooling in a corner region and for a row of jets

    Science.gov (United States)

    Siegel, R.

    1975-01-01

    A conformal mapping method was used to analyze liquid-metal-jet impingement heat transfer. The jet flow region and energy equation are transformed to correspond to uniform flow in a parallel plate channel with nonuniform heat addition along a portion of one wall. The exact solution for the wall-temperature distribution was obtained in the transformed channel, and the results are mapped back into the physical plane. Two geometries are analyzed. One is for a single slot jet directed either into an interior corner formed by two flat plates, or over the external sides of the corner; the flat plates are uniformly heated, and the corner can have various included angles. The heat-transfer coefficient at the stagnation point at the apex of the plates is obtained as a function of the corner angle, and temperature distributions are calculated along the heated walls. The second geometry is an infinite row of uniformly spaced parallel slot jets impinging normally against a uniformly heated plate. The heat-transfer behavior is obtained as a function of the spacing between the jets. Results are given for several jet Peclet numbers from 5 to 50.

  16. Deflection of a liquid metal jet/drop in a tokamak environment

    Energy Technology Data Exchange (ETDEWEB)

    Pelekasis, Nikos, E-mail: pel@uth.gr [Department of Mechanical Engineering, University of Thessaly, Volos 38334 (Greece); Benos, Lefteris [Department of Mechanical Engineering, University of Thessaly, Volos 38334 (Greece); Gomes, Rui [Associação EURATOM/IST, Centro de Fusão Nuclear, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2014-12-15

    Highlights: • We model steady flow of a liquid metal jet inside an electromagnetic field in the presence of inertia and capillary forces. • Similar analysis is performed for the motion of a liquid metal spherical drop. • The deflection of the trajectory is predicted as a function of the intensity of the externally imposed magnetic and electric fields. • The analysis is used as a proof of principle study in reference to experimental observations of jet/drop deflection due to j{sup →}×B{sup →} effects in the ISTTOK tokamak. • We discuss the possibility of using liquid metal flows as an alternative approach toward enhancing power exhaust in tokamak facilities. - Abstract: The interaction of a liquid gallium jet with plasma has been investigated in the ISTTOK tokamak. The jet was observed to remain intact during its interaction with plasma, within a certain length beyond which drop formation was observed. Significant deflection of the jet was detected as soon as plasma production was started. Furthermore, a strong dependency of the deflection magnitude on plasma position was observed that could be correlated with plasma potential gradients. As a means to capture and, possibly, quantify this effect, a preliminary magnetohydrodynamic analysis was performed in order to predict the trajectory of a jet that is traveling inside an electromagnetic field. The effect of Lorentz forces, gravity and pressure drop are accounted for in a unidirectional model that assumes a small jet radius in comparison with the trajectory length. The effect of external electric potential gradients on jet deflection was ascertained in conjunction with the importance of electric stresses in modulating the jet speed and radius. Analysis of the results reported in the ISTTOK experiments identifies the process of jet break-up as a capillary instability. The trajectory of the ensuing droplets is modeled and intensification of the deflection process is predicted in the presence of Lorentz

  17. Resource recovery using whey permeate to cultivate Phellinus linteus mycelium: Solid-state and submerged liquid fermentation.

    Science.gov (United States)

    Cho, Kyungjin; Lee, Joonyeob; Han, Gyuseong; Kim, Na Kyung; Bae, Hyokwan; Hwang, Seokhwan

    2015-10-01

    The growth characteristics of Phellinus linteus mycelium were assessed and compared under solid-state fermentation (SSF) and submerged liquid fermentation (SLF) systems on whey permeate medium. Response surface methodology was used to investigate the growth rates of mycelia under various conditions of operating temperature (TO), initial pH, and substrate concentration ([S]). The optimal growth conditions of P. linteus mycelium were determined to be 26.1°C, pH 4.6, and 60.3g of lactose/L in the SSF system, and 29.0°C, pH 5.0, and 65.3g of lactose/L in the SLF system. The maximum growth rates were predicted to be 1.92 ± 0.01 mm/d in SSF and 192.1 ± 0.0mg/L per day in SLF. Random trials were conducted to experimentally validate the evaluated optimal conditions. The differences between the modeled and observed values were only 5.3% in the SSF system and 6.1% in the SLF system. Significant engineering factors differed between the fermentation techniques; TO was significant in both cultivation systems, whereas initial pH was significant in SSF but [S] was significant in SLF. Our findings can be used to guide the operation of the bioconversion process for cultivating P. linteus mycelium using whey permeate wastewater. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  18. Experimental and numerical investigation of liquid jet impingement on superhydrophobic and hydrophobic convex surfaces

    Science.gov (United States)

    Kibar, Ali

    2017-02-01

    Experiments and numerical simulations were carried out to examine the vertical impingement a round liquid jet on the edges of horizontal convex surfaces that were either superhydrophobic or hydrophobic. The experiments examine the effects on the flow behaviour of curvature, wettability, inertia of the jet, and the impingement rate. Three copper pipes with outer diameters of 15, 22, and 35 mm were investigated. The pipes were wrapped with a piece of a Brassica oleracea leaf or a smooth Teflon sheet, which have apparent contact angles of 160° and 113°. The Reynolds number ranged from 1000 to 4500, and the impingement rates of the liquid jets were varied. Numerical results show good agreement with the experimental results for explaining flow and provide detailed information about the impingement on the surfaces. The liquid jet reflected off the superhydrophobic surfaces for all conditions. However, the jet reflected or deflected off the hydrophobic surface, depending on the inertia of the jet, the curvature of the surface, and the impingement rate. The results suggest that pressure is not the main reason for the bending of the jet around the curved hydrophobic surface.

  19. Effects of the geometric orientations of the nozzle exit on the breakup of free liquid jet

    Energy Technology Data Exchange (ETDEWEB)

    Lad, V. N.; Murthy, Z. V. P. [Sardar Vallabhbhai National Institute of Technology, Gujarat (India)

    2016-04-15

    Free liquid jets are produced through various geometric orientations of the nozzle exit. The breakup lengths of liquid jets under various geometric orientations of the nozzle exit were studied. Images of jets were captured using a high-speed camera with a maximum frame rate of 1000 frames per second and were analyzed to determine the dynamics between jets and breakup lengths. The breakup length of jets changes with the cut angle of the nozzle exit. In addition, adding polymer reduces the effect of the cut angle of the nozzle exit on the breakup length for an entire range of velocities. The effect of the cut angle on breakup length is predominant for aqueous solutions with surfactants. This work provides motivation for further computational research to study jet dynamics in a partially covered nozzle exit, such as the case in which the boundary conditions near the nozzle opening is more complex with the cut angle and its vertex position, which directly reflects liquid jet dynamics.

  20. A Study on the Influence of the Nozzle Lead Angle on the Performance of Liquid Metal Electromagnetic Micro-Jetting

    Directory of Open Access Journals (Sweden)

    Zhiwei Luo

    2016-12-01

    Full Text Available To improve the jetting performance of liquid metals, an electromagnetic micro-jetting (EMJ valve that realizes drop-on-demand (DOD jetting while not involving any valve core or moving parts was designed. The influence of the lead angle of the nozzle on the jetting of liquid metal gallium (Ga was investigated. It was found that the Lorentz force component parallel to the nozzle that jets the electrified liquid Ga is always larger than its internal friction; thus, jet can be generated with any lead angle but with different kinetic energies. Experimental results show that the mass of the jetting liquid, the jetting distance, the initial velocity of the jet, and the resulting kinetic energy of the jet increase first and then decrease. When the lead angle is 90°, the mass of the jetting liquid and the kinetic energy are at their maximum. When the angle is 80°, the initial velocity achieves its maximum, with a calculated value of 0.042 m/s. Moreover, very close and comparatively high kinetic energies are obtained at 80° and 90°, indicating that angles in between this range can produce a preferable performance. This work provides an important theoretical basis for the design of the EMJ valve, and may promote the development and application of micro electromagnetic jetting technology.

  1. Unsteady penetration of a target by a liquid jet

    Science.gov (United States)

    Uth, Tobias; Deshpande, Vikram S.

    2013-01-01

    It is widely acknowledged that ceramic armor experiences an unsteady penetration response: an impacting projectile may erode on the surface of a ceramic target without substantial penetration for a significant amount of time and then suddenly start to penetrate the target. Although known for more than four decades, this phenomenon, commonly referred to as dwell, remains largely unexplained. Here, we use scaled analog experiments with a low-speed water jet and a soft, translucent target material to investigate dwell. The transient target response, in terms of depth of penetration and impact force, is captured using a high-speed camera in combination with a piezoelectric force sensor. We observe the phenomenon of dwell using a soft (noncracking) target material. The results show that the penetration rate increases when the flow of the impacting water jet is reversed due to the deformation of the jet–target interface––this reversal is also associated with an increase in the force exerted by the jet on the target. Creep penetration experiments with a constant indentation force did not show an increase in the penetration rate, confirming that flow reversal is the cause of the unsteady penetration rate. Our results suggest that dwell can occur in a ductile noncracking target due to flow reversal. This phenomenon of flow reversal is rather widespread and present in a wide range of impact situations, including water-jet cutting, needleless injection, and deposit removal via a fluid jet. PMID:24277818

  2. Impact of a single drop on the same liquid: formation, growth and disintegration of jets

    Science.gov (United States)

    Agbaglah, G. Gilou; Deegan, Robert

    2015-11-01

    One of the simplest splashing scenarios results from the impact of a single drop on on the same liquid. The traditional understanding of this process is that the impact generates a jet that later breaks up into secondary droplets. Recently it was shown that even this simplest of scenarios is more complicated than expected because multiple jets can be generated from a single impact event and there are bifurcations in the multiplicity of jets. First, we study the formation, growth and disintegration of jets following the impact of a drop on a thin film of the same liquid using a combination of numerical simulations and linear stability theory. We obtain scaling relations from our simulations and use these as inputs to our stability analysis. We also use experiments and numerical simulations of a single drop impacting on a deep pool to examine the bifurcation from a single jet into two jets. Using high speed X-ray imaging methods we show that vortex separation within the drop leads to the formation of a second jet long after the formation of the ejecta sheet.

  3. Production of microsclerotia by Brazilian strains of Metarhizium spp. using submerged liquid culture fermentation.

    Science.gov (United States)

    Mascarin, Gabriel Moura; Kobori, Nilce Naomi; de Jesus Vital, Rayan Carlos; Jackson, Mark Alan; Quintela, Eliane Dias

    2014-05-01

    We investigated the potential production and desiccation tolerance of microsclerotia (MS) by Brazilian strains of Metarhizium anisopliae (Ma), M. acridum (Mc) and M. robertsii (Mr). These fungi were grown in a liquid medium containing 16 g carbon l⁻¹ with a carbon:nitrogen ratio of 50:1. One hundred milliliters cultures were grown in 250 ml Erlenmeyer flasks in a rotary incubator shaker at 28 °C and 200 rpm for 5 days. Five-day-old MS were harvested, mixed with diatomaceous earth (DE) and air-dried for 2 days at 30 °C. The air-dried MS-DE granular preparations were milled by mortar + pestle and stored in centrifuged tubes at either 26 or -20 °C. Desiccation tolerance and conidia production were assessed for dried MS granules by measuring hyphal germination after incubation for 2 days on water agar plates at 26 °C and for conidia production following 7 days incubation. Yields of MS by all strains of Metarhizium were 6.1-7.3 × 10⁶ l⁻¹ after 3 days growth with maximum MS yields (0.7-1.1 × 10⁷ l⁻¹) after 5 days growth. No differences in biomass accumulation were observed after 3 days growth, whereas Ma-CG168 showed the highest biomass accumulation after 5 days growth. Dried MS-DE preparations of all fungal strains were equally tolerant to desiccation (≥93 % germination) and the highest conidia production was obtained by MS granules of Mc-CG423 (4 × 10⁹ conidia g⁻¹). All MS granules showed similar stability after storage at either 26 or -20 °C for 3.5 months.

  4. New type of discharge-produced plasma source for extreme ultraviolet based on liquid tin jet electrodes

    NARCIS (Netherlands)

    Koshelev, K.N.; Krivtsun, V.M.; Ivanov, V.; Yakushev, O.; Chekmarev, A.; Koloshnikov, V.; Snegirev, E.; Medvedev, Viacheslav

    2012-01-01

    A new approach for discharge-produced plasma (DPP) extreme ultraviolet (EUV) sources based on the usage of two liquid metallic alloy jets as discharge electrodes has been proposed and tested. Discharge was ignited using laser ablation of one of the cathode jets. A system with two jet electrodes was

  5. Hydrodynamic performance of an annular liquid jet: Production of spherical shells

    Science.gov (United States)

    Kendall, J. M.

    1982-01-01

    An annular jet flow of liquid surrounding a flow of gas at its core is extremely unstable. Axisymmetric oscillations arise spontaneously, and grow with such rapidity along the axial dimension that a pinch-off of the liquid and an encapsulation of the core gas occurs within as few as four jet diameters. The shells which result thereby may be described as thick-wall bubbles, for which van der Waals forces are unimportant. A description is given of the fluid dynamic processes by which the shells are formed, and of means for preserving and promoting the geometrical of the product. The forming of metallic shells is mentioned.

  6. High efficiency energy conversion from liquid jet flow

    NARCIS (Netherlands)

    Xie, Yanbo; de Vreede, Lennart; Nguyen, Trieu; de Boer, Hans L.; Sprenkels, A.J.; van den Berg, Albert; Eijkel, Jan C.T.; Fujii, T.; Hibara, A.; Takeuchi, S.; Fukuba, T.

    2012-01-01

    We investigate the performance of a microfluidic energy conversion system using jetting flow. Preliminary results indicate that a voltage can be generated of several kilo-Volts and energy efficiencies can reach 15%. Such values are by far the highest obtained for electrokinetic conversion systems

  7. Control of ROS and RNS productions in liquid in atmospheric pressure plasma-jet system

    Science.gov (United States)

    Uchida, Giichiro; Ito, Taiki; Takenaka, Kosuke; Ikeda, Junichiro; Setsuhara, Yuichi

    2016-09-01

    Non-thermal plasma jets are of current interest in biomedical applications such as wound disinfection and even treatment of cancer tumors. Beneficial therapeutic effects in medical applications are attributed to excited species of oxygen and nitrogen from air. However, to control the production of these species in the plasma jet is difficult because their production is strongly dependent on concentration of nitrogen and oxygen from ambient air into the plasma jet. In this study, we analyze the discharge characteristics and the ROS and RNS productions in liquid in low- and high-frequency plasma-jet systems. Our experiments demonstrated the marked effects of surrounding gas near the plasma jet on ROS and RNS productions in liquid. By controlling the surround gas, the O2 and N2 main plasma jets are selectively produced even in open air. We also show that the concentration ratio of NO2- to H2O2 in liquid is precisely tuned from 0 to 0.18 in deionized water by changing N2 gas ratio (N2 / (N2 +O2)) in the main discharge gas, where high NO2- ratio is obtained at N2 gas ratio at N2 / (N2 +O2) = 0 . 8 . The low-frequency plasma jet with controlled surrounding gas is an effective plasma source for ROS and RNS productions in liquid, and can be a useful tool for biomedical applications. This study was partly supported by a Grant-in-Aid for Scientific Research on Innovative Areas ``Plasma Medical Innovation'' (24108003) from the Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT).

  8. Dynamics of liquid metal droplets and jets influenced by a strong axial magnetic field

    Science.gov (United States)

    Hernández, D.; Karcher, Ch

    2017-07-01

    Non-contact electromagnetic control and shaping of liquid metal free surfaces is crucial in a number of high-temperature metallurgical processes like levitation melting and electromagnetic sealing, among others. Other examples are the electromagnetic bending or stabilization of liquid metal jets that frequently occur in casting or fusion applications. Within this context, we experimentally study the influence of strong axial magnetic fields on the dynamics of falling metal droplets and liquid metal jets. GaInSn in eutectic composition is used as test melt being liquid at room temperature. In the experiments, we use a cryogen-free superconducting magnet (CFM) providing steady homogeneous fields of up to 5 T and allowing a tilt angle between the falling melt and the magnet axis. We vary the magnetic flux density, the tilt angle, the liquid metal flow rate, and the diameter and material of the nozzle (electrically conducting/insulating). Hence, the experiments cover a parameter range of Hartmann numbers Ha, Reynolds numbers Re, and Weber numbers We within 0 magnetic field, droplet rotation ceases and the droplets are stretched in the field direction. Moreover, we observe that the jet breakup into droplets (spheroidization) is suppressed, and in the case of electrically conducting nozzles and tilt, the jets are bent towards the field axis.

  9. Acoustically Forced Coaxial Hydrogen/Liquid Oxygen Jet Flames

    Science.gov (United States)

    2016-05-15

    propellants be stored in condensed form – e.g., kerosene, liquid oxygen in rockets • Combustion systems can no longer be designed to meet modern...of the reactants – e.g., liquid rockets, future gas turbines • When the combustion systems are for propulsion, limited tankage dictates that on-board...Symmetric recirculation zones Low-speed liquid O2 High-speed gaseous H2 Asymmetric recirculation zones Combustion case Results show large oxygen-side

  10. Liquid jet formation through the interactions of a laser-induced bubble and a gas bubble

    Science.gov (United States)

    Han, Bing; Liu, Liu; Zhao, Xiong-Tao; Ni, Xiao-Wu

    2017-10-01

    The mechanisms of the liquid jet formation from the interaction of the laser-induced and gas bubble pair are investigated and compared with the jet formation from the interaction of the laser-induced anti-phase bubble pair. The strobe photography experimental method and numerical simulations are implemented to obtain the parameter space of the optimum liquid jet, i.e. highest speed and lowest diameter. It is found that due to the enhanced "catapult effect", which is induced by the protrusion of the first bubble into the second bubble and the flip back of the elongated part of the first bubble, the optimum liquid jet of the second bubble of the laser-induced anti-phase bubble pair compared to that of the laser-induced and gas bubble pair is 54 %, 65 % and 11 % faster in speed, and 4 %, 44 % and 64 % smaller in diameter, for the 500 μm, 50 μm and 5 μm sized bubbles, respectively. The optimum dimensionless distance for the optimum jet of the laser-induced and the gas bubble is around 0.7, when the maximum bubble radius increases from ˜ 5μm to ˜500 μm, which is different from the laser-induced anti-phase bubble pairs. Besides, the optimum jet of the laser-induced bubble appeared when the bubbles are equal sized, while that of the gas bubble is independent of the relative bubble size, i.e. the liquid jet of the gas bubble has higher robustness in real liquid jet assisted applications when the laser-induced bubble size varies. However, the jet of bubble 2 could maintain a high speed (20 m/s - 35 m/s) and a low diameter (˜5 % of the maximum bubble diameter) over a big range of the dimensionless distance (0.6 - 0.9) for both of the 50 μm and 500 μm sized laser-induced equal sized anti-phase bubble pairs.

  11. The Heated Laminar Vertical Jet in a Liquid with Power-law Temperature Dependence of Density

    OpenAIRE

    Sharifulin, V. A.

    2009-01-01

    The analytical solution of heated laminar vertical jet in a liquid with power-law temperature dependence of density was obtained in the skin-layer approximation for certain values of Prandtl number. Cases of point and linear sources were considered.

  12. A new technology for revascularization of cerebral embolism using liquid jet impact.

    Science.gov (United States)

    Kodama, T; Takayama, K; Uenohara, H

    1997-12-01

    Revascularization time is the dominant factor in the treatment of acute cerebral embolism. In this paper we describe a rapid revascularization therapy using liquid jets generated by the interaction of gas bubbles with shock waves, which impact on the thrombi. The interaction of a shock wave with a gas bubble attached to an artificial thrombus which was inserted into a tube model of a cerebral artery was investigated. The shock wave was generated by detonating a microexplosive pellet. The overpressure of the shock wave was 3.0 +/- 0.6 MPa (n = 7) and 12.7 +/- 0.4 MPa (n = 3). The initial air bubble radii were varied from 0.87 mm to 2.18 mm. The subsequent collapse of the bubble was photographed using a high-speed framing camera, and the liquid jet penetrating into the artificial thrombus was visualized using x-ray photography. The penetration depth of the liquid jet increased with increasing bubble size. There was an optimal separation distance between the bubble and the shock wave source to obtain the maximum penetration depth. Liquid jets have the potential to penetrate through thrombi in as little as a few microseconds, and with very efficient ablation.

  13. A focused liquid jet formed by a water hammer in a test tube

    CERN Document Server

    Kiyama, Akihito; Ando, Keita; Kameda, Masaharu

    2015-01-01

    We investigate motion of a gas-liquid interface in a test tube induced by a large acceleration via impulsive force. We conduct simple experiments in which the tube partially filled with a liquid falls under gravity and impacts a rigid floor. A curved gas-liquid interface inside the tube reverses and eventually forms an elongated jet (i.e. the so-called a focused jet). In our experiments, there arises either vibration of the interface or increment in the velocity of a liquid jet accompanied by the onset of cavitation in the liquid column. These phenomena cannot be explained by considering pressure impulse in a classical potential flow analysis, which does not account for finite speeds of sound as well as phase change. Here we model such water-hammer events as a result of one-dimensional pressure wave propagation and its interaction with boundaries through acoustic impedance mismatching. The method of characteristics is applied to describe pressure wave interactions and the subsequent cavitation. The proposed m...

  14. Application of molecular simulations: Insight into liquid bridging and jetting phenomena

    Directory of Open Access Journals (Sweden)

    I. Nezbeda

    2015-03-01

    Full Text Available Molecular dynamics simulations have been performed on pure liquid water, aqueous solutions of sodium chloride, and polymer solutions exposed to a strong external electric field with the goal to gain molecular insight into the structural response to the field. Several simulation methodologies have been used to elucidate the molecular mechanisms of the processes leading to the formation of liquid bridges and jets (in the production of nanofibers. It is shown that in the established nanoscale structures, the molecules form a chain with their dipole moments oriented parallel to the applied field throughout the entire sample volume. The presence of ions may disturb this structure leading to its ultimate disintegration into droplets; the concentration dependence of the threshold field required to stabilize a liquid column has been determined. Conformational changes of the polymer in the jetting process have also been observed.

  15. Pulsed laser-induced liquid jet: evolution from shock/bubble interaction to neurosurgical application

    Science.gov (United States)

    Nakagawa, A.; Kumabe, T.; Ogawa, Y.; Hirano, T.; Kawaguchi, T.; Ohtani, K.; Nakano, T.; Sato, C.; Yamada, M.; Washio, T.; Arafune, T.; Teppei, T.; Atsushi, K.; Satomi, S.; Takayama, K.; Tominaga, T.

    2017-01-01

    The high-speed liquid (water) jet has distinctive characteristics in surgical applications, such as tissue dissection without thermal damage and small blood vessel preservation, that make it advantageous over more conventional instruments. The continuous pressurized jet has been used since the first medical application of water jets to liver surgery in the 1980s, but exhibited drawbacks partly related to the excess water supply required and unsuitability for application to microsurgical instruments intended for deep, narrow lesions (endoscopic instrumentation and catheters) due to limitations in miniaturization of the device. To solve these issues, we initiated work on the pulsed micro-liquid jet. The idea of the pulsed micro-liquid jet originated from the observation of tissue damage by shock/bubble interactions during extracorporeal shock wave lithotripsy and evolved into experimental application for recanalization of cerebral embolisms in the 1990s. The original method of generating the liquid jet was based on air bubble formation and microexplosives as the shock wave source, and as such could not be applied clinically. The air bubble was replaced by a holmium:yttrium-aluminum-garnet (Ho:YAG) laser-induced bubble. Finally, the system was simplified and the liquid jet was generated via irradiation from the Ho:YAG laser within a liquid-filled tubular structure. A series of investigations revealed that this pulsed laser-induced liquid jet (LILJ) system has equivalent dissection and blood vessel preservation characteristics, but the amount of liquid usage has been reduced to less than 2 μ l per shot and can easily be incorporated into microsurgical, endoscopic, and catheter devices. As a first step in human clinical studies, we have applied the LILJ system for the treatment of skull base tumors through the transsphenoidal approach in 9 patients (7 pituitary adenomas and 2 chordomas), supratentorial glioma (all high grade glioma) in 8 patients, including one with

  16. EURISOL Multi-MW Target: Investigation of the hydrodynamics of liquid metal (Hg) jet

    CERN Document Server

    Freibergs, J

    In order to develop a windowless target it is necessary to investigate the hydrodynamics of liquid metal (Hg) jet. On the basis of the schematic layout of a high-power target module presented in Ref. [2], and the parameters of the windowless target (speed of the mercury jet up to 30 m/s, diameter of jet 10-20 mm and length of jet about 1 m), a first estimation of the parameters of the main components of a Hg-loop has been obtained by the Institute of Physics, University of Latvia. A preliminary engineering design of a functional Hg-loop to be constructed soon is also proposed. A simplified water stand has been developed with the ability of testing different Hg-nozzle configurations. The tests carried out showed that the kinetic energy of the jet is so high that the coaxial water flow at contact point is transformed into small bubbles (spray). The characteristics of the jet were shown to depend on the pressure of the stand.

  17. An experimental study of the behavior of liquid jets subjected to thermodynamic subcritical and supercritical conditions

    Science.gov (United States)

    Spegar, Timothy Daniel

    As pressures and temperatures have risen in internal combustion engines, liquid fuel injection into an environment exceeding the critical pressure and temperature of the fuel is routine. If the fuel/oxidizer mixture reaches critical conditions, surface tension vanishes while the vapor/liquid density ratio approaches unity, altering the mixing behavior of the fuel and oxidizer from the well-studied behavior of jets injected into environments of more modest pressures and temperatures. To elucidate these issues, an experimental study of n-pentane jet breakup in high pressure and high temperature nitrogen environments was performed. Specifically, n-pentane at 20°C was injected transversely into nitrogen through a plain orifice atomizer at velocities varying from 1.0 m/sec to 6.0 m/sec. The nitrogen temperature and pressure were varied from 20°C to 300°C and 100 psig to 1500 psig, respectively. The experiments were carried out in an optically accessible test chamber and two-dimensional spontaneous Raman imaging was employed to attempt to quantify the degree of jet vaporization. An analysis of the jets' breakup mechanism, continuous length, drag coefficient and wake fuel concentration was conducted to determine if jet behavior at extreme pressures and temperatures could be explained by the characteristic decrease in surface tension and increase in gas/liquid density ratio as the critical point is reached. Though not all results could be explained by the appropriate changes in surface tension and the gas/liquid density ratio, jet behavior at ambient conditions in excess of the liquid critical point was observed to differ from behavior typical of jets injected at relatively low pressures. Furthermore, little variation in wake intensity was seen, but this is conceivable considering the inherent difficulties in spontaneous Raman scattering, most notably, its intrinsic weakness. Suggestions for improving the results of the Raman measurements employed in this investigation

  18. Liquid jet breakup and atomization in rocket chambers under dense spray conditions

    Science.gov (United States)

    Kuo, Kenneth K.; Cheung, Fan-Bill; Woodward, Roger D.; Garner, Kenneth N.

    1991-01-01

    Two advanced diagnostic techniques were established and employed in this project. The first technique involves the use of a real-time x ray radiography system along with a high-speed CCD Xybion camera and an advanced digital image processor to investigate the breakup processes of the liquid core. The focus of this part of the project is to determine the inner structure of the liquid jet and via thin sheets of laser light, with the scatters light being photographed by a Xybion electronic camera synchronized to the laser pulse. This technique, which is capable of recording the breakup event occurring within 25 nano-seconds, enables us to freeze the motions of the jet and liquid droplets. The focus of this part of the project is to determine the outer structure of the liquid jet and to discover the configuration of the surface waves, the spray pattern, and the droplet size distribution in the non-dilute region. Results obtained by these two advanced diagnostic techniques will provide the much needed database for model development and accurate prediction of engine performance. The present work also represents a breakthrough in the area of advanced diagnostics of dense sprays.

  19. Numerical studies of the effects of jet-induced mixing on liquid-vapor interface condensation

    Science.gov (United States)

    Lin, Chin-Shun

    1989-01-01

    Numerical solutions of jet-induced mixing in a partially full cryogenic tank are presented. An axisymmetric laminar jet is discharged from the central part of the tank bottom toward the liquid-vapor interface. Liquid is withdrawn at the same volume flow rate from the outer part of the tank. The jet is at a temperature lower than the interface, which is maintained at a certain saturation temperature. The interface is assumed to be flat and shear-free and the condensation-induced velocity is assumed to be negligibly small compared with radial interface velocity. Finite-difference method is used to solve the nondimensional form of steady state continuity, momentum, and energy equations. Calculations are conducted for jet Reynolds numbers ranging from 150 to 600 and Prandtl numbers ranging from 0.85 to 2.65. The effects of above stated parameters on the condensation Nusselt and Stanton numbers which characterize the steady-state interface condensation process are investigated. Detailed analysis to gain a better understanding of the fundamentals of fluid mixing and interface condensation is performed.

  20. Influence of spatial curvature of a liquid jet on the rainbow positions: Ray tracing and experimental study

    Science.gov (United States)

    Duan, Qingwei; Zhong, Ruliang; Han, Xiang'e.; Ren, Kuan Fang

    2017-07-01

    Rainbow refractometry is largely used in optical metrology of particles thanks to its advantages of being non-intrusive, precise and fast. Many authors have contributed to its development and the application in the characterization of liquid jets/droplets. The researches reported in the literature are mainly for the spherical droplets or the liquid jets which can be considered as a cylinder of constant section. However, the section of a real liquid jet, even in the simplest configuration, varies with distance from the exit. The influence of the spatial curvature of the jets must, therefore, be taken into account. In this paper, we report experimental measurements of the shifts of the rainbow positions in the horizontal and vertical directions of a liquid jet and the theoretical investigation with the vectorial complex ray model. It is shown that the shifts of rainbow positions are very sensitive to the spatial curvature of the jets. This work is hoped to provide a new approach to characterizing the structure and the instability of liquid jets.

  1. Formation and post-formation dynamics of bacterial biofilm streamers as highly viscous liquid jets

    CERN Document Server

    Das, Siddhartha

    2013-01-01

    It has been recently reported that in presence of low Reynolds number (Re<<1) transport, preformed bacterial biofilms, several hours after their formation, may degenerate in form of filamentous structures, known as streamers. In this letter, we explain that such streamers form as the highly viscous liquid states of the intrinsically viscoelastic biofilms. Such "viscous liquid" state can be hypothesized by noting that the time of appearance of the streamers is substantially larger than the viscoelastic relaxation time scale of the biofilms, and this appearance is explained by the inability of a viscous liquid to withstand an external shear. Further, by identifying the post formation dynamics of the streamers as that of a viscous liquid jet in a surrounding flow field, we can interpret several unexplained issues associated with the post-formation dynamics of streamers, such as the clogging of the flow passage or the exponential time growth of streamer dimensions.

  2. Submerged Friction-Stir Welding (SFSW) Underwater and Under Liquid Nitrogen: An Improved Method to Join Al Alloys to Mg Alloys

    Science.gov (United States)

    Mofid, Mohammad Ammar; Abdollah-Zadeh, Amir; Ghaini, Farshid Malek; Gür, Cemil Hakan

    2012-12-01

    Submerged friction-stir welding (SFSW) underwater and under liquid nitrogen is demonstrated as an alternative and improved method for creating fine-grained welds in dissimilar metals. Plates of AZ31 (Mg alloy) and AA5083 H34 were joined by friction-stir welding in three different environments, i.e., in air, water, and liquid nitrogen at 400 rpm and 50 mm/min. The temperature profile, microstructure, scanning electron microscopy (SEM)-energy-dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD), hardness, and tensile testing results were evaluated. In the stir zone of an air-welded specimen, formation of brittle intermetallic compounds of Al3Mg2, Al12Mg17, and Al2Mg3 contributed to cracking in the weld nugget. These phases were formed because of constitutional liquation. Friction-stir welding underwater and under liquid nitrogen significantly suppresses the formation of intermetallic compounds because of the lower peak temperature. Furthermore, the temperature profiles plotted during this investigation indicate that the largest amount of ∆ T is generated by the weld under liquid nitrogen, which is performed at the lowest temperature. It is shown that in low-temperature FSW, the flow stress is higher, plastic contribution increases, and so adiabatic heating, a result of high strain and high strain-rate deformation, drives the recrystallization process beside frictional heat.

  3. Jet pinch-off and drop formation in immiscible liquid-liquid systems

    Energy Technology Data Exchange (ETDEWEB)

    Webster, D.R. [School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Longmire, E.K. [Dept. of Aerospace Engineering and Mechanics, Univ. of Minnesota, Minneapolis, MN (United States)

    2001-01-01

    The behavior of glycerin-water jets flowing into immiscible ambients of Dow Corning 200 fluid was investigated using laser induced fluorescence (LIF). Undistorted images were obtained by matching the index of refraction of the fluids. A sinusoidal perturbation was superposed on the flow to phase lock the drop formation. The forcing frequency dramatically affected the size, spacing, and number of drops that formed within a forcing cycle and the angle between drops and the jet interface just before pinch-off. Two fluid combinations were studied with similar density ratios, but viscosity ratios differing by a factor of 20. The viscosity ratio affected the jet stability as well as pinch-off angles and drop size. (orig.)

  4. Thorough small-angle X-ray scattering analysis of the instability of liquid micro-jets in air.

    Science.gov (United States)

    Marmiroli, Benedetta; Cacho-Nerin, Fernando; Sartori, Barbara; Pérez, Javier; Amenitsch, Heinz

    2014-01-01

    Liquid jets are of interest, both for their industrial relevance and for scientific applications (more important, in particular for X-rays, after the advent of free-electron lasers that require liquid jets as sample carrier). Instability mechanisms have been described theoretically and by numerical simulation, but confirmed by few experimental techniques. In fact, these are mainly based on cameras, which is limited by the imaging resolution, and on light scattering, which is hindered by absorption, reflection, Mie scattering and multiple scattering due to complex air/liquid interfaces during jet break-up. In this communication it is demonstrated that synchrotron small-angle X-ray scattering (SAXS) can give quantitative information on liquid jet dynamics at the nanoscale, by detecting time-dependent morphology and break-up length. Jets ejected from circular tubes of different diameters (100-450 µm) and speeds (0.7-21 m s(-1)) have been explored to cover the Rayleigh and first wind-induced regimes. Various solvents (water, ethanol, 2-propanol) and their mixtures have been examined. The determination of the liquid jet behaviour becomes essential, as it provides background data in subsequent studies of chemical and biological reactions using SAXS or X-ray diffraction based on synchrotron radiation and free-electron lasers.

  5. Numerical investigation on cryogenic liquid jet under transcritical and supercritical conditions

    Science.gov (United States)

    Li, Liang; Xie, Maozhao; Wei, Wu; Jia, Ming; Liu, Hongsheng

    2018-01-01

    Cryogenic fluid injection and mixing under transcritical and supercritical conditions is numerically investigated with emphasis on the difference of the mechanism and characteristics between the two injections. A new solver is developed which is capable of handling the nonideality of the equation of state and the anomalies in fluid transport properties and is incorporated into the CFD software OpenFOAM. The new solver has been validated against available experimental data and exhibits a good performance. Computational results indicates that the differences between transcritical and supercritical injections are mainly induced by the pseudo-boiling phenomenon, resulting in that the transcritical jet has a longer cold liquid core and an isothermal expansion occurs at the surface of the cold core. The thickness of the supercritical mixing layer and its increase value along the jet direction are greater than its transcritical counterpart. The high-temperature jet whose initial temperature is above the pseudo-boiling temperature has the ability of enhancing the mixing of the jet with the surrounding gas.

  6. Effect of Liquid Viscosity on a Liquid Jet Produced by the Collapse of a Laser-Induced Bubble near a Rigid Boundary

    Science.gov (United States)

    Liu, Xiu-mei; He, Jie; Lu, Jian; Ni, Xiao-wu

    2009-01-01

    The collapse of a laser-induced cavitation bubble near a rigid boundary and its dependence on liquid (kinematic) viscosity are investigated experimentally by fiber-coupling optical beam deflection (OBD). Cavitation bubble tests are performed using a mixture of glycerin and water of various concentrations, and the viscosity ranges from 1.004×10-6 to 51.30×10-6 m2/s. Combining the detection principles of this detector with a widely used laser ablation model, actual liquid-jet impact forces are presented for the mentioned viscosity range. In addition, based on the model of a collapsing bubble, some characteristic parameters, such as bubble lifetime, the maximum bubble radius, and liquid-jet impact pressure, are also obtained as a function of liquid viscosity. The main conclusion is that the liquid jet is a dominant factor in cavitation damage and can be modified by liquid viscosity. A high viscosity reduces the liquid-jet impact force and cavitation erosion markedly. The mechanism of the liquid viscosity effect on cavitation erosion has also been discussed.

  7. Turbulent buoyant jets and plumes

    CERN Document Server

    Rodi, Wolfgang

    The Science & Applications of Heat and Mass Transfer: Reports, Reviews, & Computer Programs, Volume 6: Turbulent Buoyant Jets and Plumes focuses on the formation, properties, characteristics, and reactions of turbulent jets and plumes. The selection first offers information on the mechanics of turbulent buoyant jets and plumes and turbulent buoyant jets in shallow fluid layers. Discussions focus on submerged buoyant jets into shallow fluid, horizontal surface or interface jets into shallow layers, fundamental considerations, and turbulent buoyant jets (forced plumes). The manuscript then exami

  8. Instability of Slender Liquid Jet in AC Electric Field of Arbitrary Frequency

    Science.gov (United States)

    Demekhin, Evgeny A.; Polyanskikh, Sergey V.

    2010-09-01

    In the present work stability of capillary micro-jet of electrolyte solution in alternating longitudinal electric field is investigated theoretically. The gravity effects are neglected. The problem is described by strongly coupled nonlinear system of PDEs for ion transport, electric field and fluid flow under assumption of a viscous Newtonian liquid. The Debye layer thickness is supposed to be small compared with initial jet radius. The Peclet number based on the Debye layer thickness is assumed to be small. These assumptions lead to substantial simplification of the problem. Slender-body theory is used to further simplification of initial statement. Used asymptotic method allows to reduce initially infinite system to three-dimensional ODE with time-periodic coefficients. It is shown that monodromy operator has the only real unstable multiplier. In the case of high-frequency alternating electric field the results showed good agreement with the ones provided by averaging theory.

  9. Interfacial and velocity characteristics of pinch-off modes in liquid/liquid jet systems

    Science.gov (United States)

    Milosevic, Ilija; Longmire, Ellen

    2003-11-01

    Forced jets of water/glycerin mixture flowing into silicone oil were investigated. An index-matching technique was employed, and the flow was examined by laser-induced fluorescence and PIV. Experiments were performed at several Reynolds and Strouhal numbers (Re 50-80, St 2-3) while holding viscosity ratio (mi/mo = 1.6) and Ohnesorge number (Oh = 0.013) constant. The upstream and downstream interface angles as well as velocity fields surrounding the pinch off location were measured for several distinct modes; e.g. a primary drop separating from the jet, a primary drop splitting in two, and a satellite drop separating from the jet. At the smallest observable scales ( 15 microns), the angles varied with the pinch-off mode. The angles in the splitting drop mode appeared to converge toward values predicted by similarity theory, but angles in the other modes did not. The differences in behavior will be discussed in terms of the local velocity and vorticity fields surrounding each mode. Detailed measurements include centerline velocity and local strain and rotation rate through each pinch-off event. *supported by DOE (DE-FG02-98ER14869)

  10. Numerical analysis of the temporal and spatial instabilities on an annular liquid jet

    Science.gov (United States)

    Zandian, Arash

    A numerical study of the temporal and spatial instabilities appearing on the interface of an annular liquid jet emerging from an orifice and flowing into a high pressure gas medium has been performed using Direct Numerical Simulation. The purpose of this study is to gain a better insight into the dominant mechanisms in the atomization of annular liquid jets during the start-up portion of the injection. The effects on the growth rate and wavelength of the emerging Kelvin-Helmholtz and Rayleigh-Taylor instabilities of various flow parameters have been investigated: the Reynolds and Weber numbers; fluids properties like gas-to-liquid density and viscosity ratios; and geometrical parameters involved in the problem such as thickness-to-diameter ratio of the liquid sheet. The Reynolds numbers used in this study are in the range from 3,000 to 30,000, and the Weber numbers are in the range of 6,000 up to 150,000. The convergence rate and length of the liquid jet has been also computed and compared for different cases. A characteristic convergence time has been proposed based on the obtained results. Use has been made of an unsteady axisymmetric code with a finite-volume solver of the Navier-Stokes equations for liquid streams and adjacent gas and a level-set method for the liquid/gas interface tracking. Two significant velocity reversals were detected on the axis of symmetry for all flow Reynolds numbers; the one closer to the nozzle exit being attributed to the recirculation zone, and the one farther downstream corresponding to the annular jet collapse on the centerline. The effects of different flow parameters on the location of these velocity reversals are studied. The results indicate that the convergence length and time increase significantly with the gas density and liquid viscosity and decrease with the liquid sheet thickness, while the effects of the gas viscosity and the surface tension are not so considerable. The range of unstable Kelvin-Helmholtz and Rayleigh

  11. Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

    Energy Technology Data Exchange (ETDEWEB)

    Buschman, Francis X., E-mail: Francis.Buschman@unnpp.gov; Aumiller, David L.

    2017-02-15

    Highlights: • Direct contact condensation data on liquid jets up to 1.7 MPa in pure steam and in the presence of noncondensable gas. • Identified a pressure effect on the impact of noncondensables to suppress condensation heat transfer not captured in existing data or correlations. • Pure steam data is used to develop a new correlation for condensation heat transfer on subcooled liquid jets. • Noncondensable data used to develop a modification to the renewal time estimate used in the Young and Bajorek correlation for condensation suppression in the presence of noncondensables. • A jet injection boundary condition, using a sub-grid jet condensation model, is developed for COBRA-IE which provides a more detailed estimate of the condensation rate on the liquid jet and allows the use of jet specific closure relationships. - Abstract: Condensation on liquid jets is an important phenomenon for many different facets of nuclear power plant transients and analyses such as containment spray cooling. An experimental facility constructed at the Pennsylvania State University, the High Pressure Liquid Jet Condensation Heat Transfer facility (HPLJCHT), has been used to perform steady-state condensation heat transfer experiments in which the temperature of the liquid jet is measured at different axial locations allowing the condensation rate to be determined over the jet length. Test data have been obtained in a pure steam environment and with varying concentrations of noncondensable gas. This data extends the available jet condensation data from near atmospheric pressure up to a pressure of 1.7 MPa. An empirical correlation for the liquid side condensation heat transfer coefficient has been developed based on the data obtained in pure steam. The data obtained with noncondensable gas were used to develop a correlation for the renewal time as used in the condensation suppression model developed by Young and Bajorek. This paper describes a new sub-grid liquid jet

  12. Simultaneous Multiphase PIV of Capillary Waves on a High Velocity Liquid Jet

    Science.gov (United States)

    Andre, Matthieu; Bardet, Philippe

    2013-11-01

    Relaxation of a laminar boundary layer below the free surface of a jet is inviscidly unstable and can roll-up which generates millimeter size waves. The latter largely modify important characteristics of jets such as heat and mass transfers between phases and can lead to breakup, or air entrainment. Two dimensional linear stability analysis predicts the initial disturbance wavelength and growth rate for inviscid flows; it does not take into account the effects of viscosity, non-linearity, or actual boundary layer profile. Because of the small temporal and spatial scales associated with this flow, few experimental data are available. Data acquisition is further complicated by the presence of a free surface with steep waves. The current experiment consists in a 20.3 mm × 146.0 mm water slab laminar jet flowing onto a transparent open-channel at a Reynolds number of 2.9 × 104 to 1.4 × 105. Two high speed cameras are employed to obtain velocity fields simultaneously in the liquid and in the gas phase with Particle Image Velocimetry (PIV). Fluorescent dye is added in the liquid in order to improve interface detection. Each phase is recorded at 10 kHz, leading to a temporal resolution of 100 μs and high magnification lenses give a spatial resolution of 200 μm. The results confirm the mechanism of formation of the short surface waves. Generation of surface vorticity is identified in high curvature regions. Knowledge of the velocities in both phases allows studying vorticity flux through the free surface. The latter stage of wave growth can be accompanied by the formation of a vortex pair in the liquid and air entrapment.

  13. Electrospinning of a viscous-capillary jet within dielectric liquid bath

    Science.gov (United States)

    Riboux, Guillaume

    2010-11-01

    An experimentally characterization of the whipping motion of an electrified micro-jet of glycerine immersed within a liquid bath is carried out. In particular, the determination of the evolution of the frequency, the wavelength and the amplitude of the whipping oscillations as a function of the dimensionless parameters: the capillary number, the electrical Bond number and a residence to electrical relaxation time ratio. The presence of whipping requires threshold values of the three parameters to be reached. The electrified cone radius strongly depend on the capillary and electrical Bond numbers. The whipping behaviour, which depends on the capillary number but only weakly on the electrical Bond number, presents three different regimes: periodic, quasi-periodic or chaotic. Results showed that the wavelength and the frequency of the jet whipping depend strongly of the electrical Bond number. The phase velocity of the whipping jet is constant and proportional to the visco-capillary velocity. The detected whipping envelope showed self-similar behavior after appropriate normalization and evolved downstream as a 3/2 power law of the normalized distance.

  14. Enhanced Liquid Metal Micro Droplet Generation by Pneumatic Actuation Based on the StarJet Method

    Directory of Open Access Journals (Sweden)

    Peter Koltay

    2013-03-01

    Full Text Available We present a novel pneumatic actuation system for generation of liquid metal droplets according to the so-called StarJet method. In contrast to our previous work, the performance of the device has been significantly improved: the maximum droplet generation frequency in continuous mode has been increased to fmax = 11 kHz (formerly fmax = 4 kHz. In addition, the droplet diameter has been reduced to 60 μm. Therefore, a new fabrication process for the silicon nozzle chips has been developed enabling the production of smaller nozzle chips with higher surface quality. The size of the metal reservoir has been increased to hold up to 22 mL liquid metal and the performance and durability of the actuator has been improved by using stainless steel and a second pneumatic connection to control the sheath flow. Experimental results are presented regarding the characterization of the droplet generation, as well as printed metal structures.

  15. In-liquid arc plasma jet and its application to phenol degradation

    KAUST Repository

    Liu, Jing-Lin Lin

    2018-02-07

    We present a new method for achieving chemical reactions induced by plasmas with liquids—an in-liquid arc plasma jet system—designed to have a few advantages over the existing methods. High-speed imaging and optical emission spectroscopy were adopted to highlight the physical aspects of the in-liquid arc plasma jet system, and the feasibility of the system was investigated in a wastewater treatment case with phenol as the model contaminant. We found that the specific energy input is a reasonable parameter by which to characterize the overall process. The phenol removal reaction could be modeled as a pseudo-first-order reaction, and the reaction constant became smaller as the phenol concentration increased. However, complete decomposition of the phenol into water and carbon dioxide required very high energy because the final intermediate, oxalic acid, is relatively stable. Detailed chemical and physical analyses, including byproducts, ions, solution acidity, and conductivity, were conducted to evaluate this new method for use in the appropriate applications.

  16. Experimental and numerical investigations of the impingement of an oblique liquid jet onto a superhydrophobic surface: energy transformation

    Energy Technology Data Exchange (ETDEWEB)

    Kibar, Ali, E-mail: alikibar@kocaeli.edu.tr [Department of Mechanical and Material Technologies, Kocaeli University, 41285, Arslanbey Campus, Kocaeli (Turkey)

    2016-02-15

    This study presents the theory of impinging an oblique liquid jet onto a vertical superhydrophobic surface based on both experimental and numerical results. A Brassica oleracea leaf with a 160° apparent contact angle was used for the superhydrophobic surface. Distilled water was sent onto the vertical superhydrophobic surface in the range of 1750–3050 Reynolds number, with an inclination angle of 20°−40°, using a circular glass tube with a 1.75 mm inner diameter. The impinging liquid jet spread onto the surface governed by the inertia of the liquid and then reflected off the superhydrophobic surface due to the surface energy of the spreading liquid. Two different energy approaches, which have time-scale and per-unit length, were performed to determine transformation of the energy. The kinetic energy of the impinging liquid jet was transformed into the surface energy with an increasing interfacial surface area between the liquid and air during spreading. Afterwards, this surface energy of the spreading liquid was transformed into the reflection kinetic energy. (paper)

  17. Formation and crystallisation of a liquid jet in a film exposed to a tightly focused laser beam

    Science.gov (United States)

    Anisimov, S. I.; Zhakhovsky, V. V.; Inogamov, N. A.; Murzov, S. A.; Khokhlov, V. A.

    2017-06-01

    This paper considers the effect of an ultrashort laser pulse on a thin gold film on a glass substrate at a focal spot size near 1 μm. We analyse the motion and thermal history of a film that has peeled off from the substrate in the heating spot as a consequence of melting. The detached zone is shown to form a domeshaped bump whose motion is hindered by surface tension. After the dome stops and turns back, towards the substrate, a jet begins to grow on its top. Concurrently, because of the heat dissipation in the film, melt recrystallisation begins, involving first the dome and then the jet. The liquid part of the jet elongates and breaks up into droplets because of the Plateau-Rayleigh instability development. The formation of a neck and the detachment of the last droplet occur in the solidification zone between the crystalline and liquid parts of the jet. The propagation of the crystallisation zone in the jet leads the necking process, so neck disruption occurs in the solid phase under nonequilibrium crystallisation conditions (the melt temperature is hundreds of kelvins lower than the melting point), at limiting mechanical stress and at high deformation rates. As a result, the jet transforms into a high needle with an extremely small tip radius (a few nanometres).

  18. OPTIMIZED DETERMINATION OF TRACE JET FUEL VOLATILE ORGANIC COMPOUNDS IN HUMAN BLOOD USING IN-FIELD LIQUID-LIQUID EXTRACTION WITH SUBSEQUENT LABORATORY GAS CHROMATOGRAPHIC-MASS SPECTROMETRIC ANALYSIS AND ON-COLUMN LARGE VOLUME INJECTION

    Science.gov (United States)

    A practical and sensitive method to assess volatile organic compounds (VOCs) from JP-8 jet fuel in human whole blood was developed by modifying previously established liquid-liquid extraction procedures, optimizing extraction times, solvent volume, specific sample processing te...

  19. Inflammatory and Oxidative Stress Responses of an Alveolar Epithelial Cell Line to Airborne Zinc Oxide Nanoparticles at the Air-Liquid Interface: A Comparison with Conventional, Submerged Cell-Culture Conditions

    Directory of Open Access Journals (Sweden)

    Anke-Gabriele Lenz

    2013-01-01

    Full Text Available The biological effects of inhalable nanoparticles have been widely studied in vitro with pulmonary cells cultured under submerged and air-liquid interface (ALI conditions. Submerged exposures are experimentally simpler, but ALI exposures are physiologically more realistic and hence potentially biologically more meaningful. In this study, we investigated the cellular response of human alveolar epithelial-like cells (A549 to airborne agglomerates of zinc oxide (ZnO nanoparticles at the ALI, compared it to the response under submerged culture conditions, and provided a quantitative comparison with the literature data on different types of particles and cells. For ZnO nanoparticle doses of 0.7 and 2.5 μg ZnO/cm2 (or 0.09 and 0.33 cm2 ZnO/cm2, cell viability was not mitigated and no significant effects on the transcript levels of oxidative stress markers (HMOX1, SOD-2 and GCS were observed. However, the transcript levels of proinflammatory markers (IL-8, IL-6, and GM-CSF were induced to higher levels under ALI conditions. This is consistent with the literature data and it suggests that in vitro toxicity screening of nanoparticles with ALI cell culture systems may produce less false negative results than screening with submerged cell cultures. However, the database is currently too scarce to draw a definite conclusion on this issue.

  20. High Fidelity Simulation of Liquid Jet in Cross-flow Using High Performance Computing

    Science.gov (United States)

    Soteriou, Marios; Li, Xiaoyi

    2011-11-01

    High fidelity, first principles simulation of atomization of a liquid jet by a fast cross-flowing gas can help reveal the controlling physics of this complicated two-phase flow of engineering interest. The turn-around execution time of such a simulation is prohibitively long using typically available computational resources today (i.e. parallel systems with ~O(100) CPUs). This is due to multiscale nature of the problem which requires the use of fine grids and time steps. In this work we present results from such a simulation performed on a state of the art massively parallel system available at Oakridge Leadership Computing Facility (OLCF). Scalability of the computational algorithm to ~2000 CPUs is demonstrated on grids of up to 200 million nodes. As a result, a simulation at intermediate Weber number becomes possible on this system. Results are in agreement with detailed experiment measurements of liquid column trajectory, breakup location, surface wavelength, onset of surface stripping as well as droplet size and velocity after primary breakup. Moreover, this uniform grid simulation is used as a base case for further code enhancement by evaluating the feasibility of employing Adaptive Mesh Refinement (AMR) near the liquid-gas interface as a means of mitigating computational cost.

  1. Cooling of a multichip electronic module by means of confined two-dimensional jets of dielectric liquid

    Science.gov (United States)

    Wadsworth, D. C.; Mudawar, I.

    1990-11-01

    Experiments were performed to investigate single-phase heat transfer from a smooth 12.7 x 12.7-sq-mm simulated chip to a two-dimensional jet of dielectric FC-72 liquid issuing from a thin rectangular slot into a channel confined between the chip surface and nozzle plate. The effects of jet width, confinement channel height, and impingement velocity have been examined. Channel height had a negligible effect on the heat-transfer performance of the jet. A correlation for the convective heat-transfer coefficient is presented as a function of jet width, heater length, flow velocity, and fluid properties. A self-contained multichip cooling module consisting of a 3 x 3 array of heat sources confirmed the uniformity and predictability of cooling for each of the nine chips, and proved the cooling module is well suited for packaging large arrays of high-power-density chips.

  2. Extensional flow of liquid jets formed by bubble collapse in oils under cavitation-generated pressure waves

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, M.S.; Brown, S.W.J.; Williams, P.R. [Department of Chemical and Biological Process Engineering, University of Wales Swansea, Singleton Park, SA2 8PP, Swansea (United Kingdom)

    2004-03-01

    We report a study of liquid jets which are formed by bubble collapse under cavitation-generated pressure waves. The results obtained for jets formed from samples of a multigrade motor oil provide the first evidence that such jets experience a significant degree of extensional deformation, at high rates of extension. The results support the conclusion that the reduced velocity and final length of such jets, relative to their Newtonian counterparts, is due to an increased resistance to extensional flow. Insofar as the multigrade oils studied here are made viscoelastic by polymer additives and evidently possess significant levels of resistance to extension, the results provide evidence in support of a mitigating effect of viscoelasticity on a cavitation damage mechanism, as mooted by Berker et al. (J Non Newton Fluid Mech 56:333, 1995). (orig.)

  3. Extensional flow of liquid jets formed by bubble collapse in oils under cavitation-generated pressure waves

    Science.gov (United States)

    Barrow, M. S.; Brown, S. W. J.; Williams, P. R.

    We report a study of liquid jets which are formed by bubble collapse under cavitation-generated pressure waves. The results obtained for jets formed from samples of a multigrade motor oil provide the first evidence that such jets experience a significant degree of extensional deformation, at high rates of extension. The results support the conclusion that the reduced velocity and final length of such jets, relative to their Newtonian counterparts, is due to an increased resistance to extensional flow. Insofar as the multigrade oils studied here are made viscoelastic by polymer additives and evidently possess significant levels of resistance to extension, the results provide evidence in support of a mitigating effect of viscoelasticity on a cavitation damage mechanism, as mooted by Berker et al. (J Non Newton Fluid Mech 56:333, 1995).

  4. Optimization of liquid jet system for laser-induced breakdown spectroscopy analysis

    Science.gov (United States)

    Skočovská, Katarína; Novotný, Jan; Prochazka, David; Pořízka, Pavel; Novotný, Karel; Kaiser, Jozef

    2016-04-01

    A complex optimization of geometrical and temporal parameters of a jet system (developed in Laser-induced breakdown spectroscopy (LIBS) laboratory of Brno University of Technology) for direct elemental analysis of samples in a liquid state of matter using LIBS was carried out. First, the peristaltic pump was synchronized with the flashlamp of the ablation laser, which reduced variation of the ablated sample amount. Also, the fluctuation of the laser ray angle incident on the jet surface was diminished. Such synchronization reduced signal standard deviations and thus increased repeatability of the measurements. Then, laser energy and distance of the focusing lens from the sample were optimized. The gate delay time and the gate width were optimized for single pulse (SP) experiments; the gate delay time and the inter-pulse delay were optimized for the use of double pulse (DP) variant. Results were assessed according to the highest signal to noise ratios and the lowest relative standard deviations of the signal. The sensitivity of the single pulse and the double pulse LIBS for the detection of heavy metals traces, copper (Cu i at 324.754 nm) and lead (Pb i at 405.781 nm), in aqueous solution of copper (ii) sulfate and lead (ii) acetate, was estimated in terms of limits of detection (LODs). As a result, sensitivity improvement of DP LIBS system was observed, the LOD of Cu obtained with DP was calculated 40% lower than LOD gained from SP technique.

  5. Assessment of three turbulence model performances in predicting water jet flow plunging into a liquid pool

    Directory of Open Access Journals (Sweden)

    Zidouni Kendil Faiza

    2010-01-01

    Full Text Available The main purpose of the current study is to numerically investigate, through computational fluid dynamics modeling, a water jet injected vertically downward through a straight circular pipe into a water bath. The study also aims to obtain a better understanding of jet behavior, air entrainment and the dispersion of bubbles in the developing flow region. For these purposes, three dimensional air and water flows were modeled using the volume of fluid technique. The equations in question were formulated using the density and viscosity of a 'gas-liquid mixture', described in terms of the phase volume fraction. Three turbulence models with a high Reynolds number have been considered i. e. the standard k-e model, realizable k-e model, and Reynolds stress model. The predicted flow patterns for the realizable k-e model match well with experimental measurements found in available literature. Nevertheless, some discrepancies regarding velocity relaxation and turbulent momentum distribution in the pool are still observed for both the standard k-e and the Reynolds stress model.

  6. HYDRODYNAMICS AND MASS-TRANSFER CHARACTERISTICS OF A LOOP-VENTURI REACTOR WITH A DOWNFLOW LIQUID JET EJECTOR

    NARCIS (Netherlands)

    CRAMERS, PHMR; BEENACKERS, AACM; VANDIERENDONCK, LL

    1992-01-01

    The hydrodynamics and mass transfer characteristics of a loop-venturi reactor have been investigated using a downflow liquid jet ejector. The specific interfacial area of the ejector and the main holding vessel were determined separately. The cobalt catalyzed sulfite oxidation was used as a model

  7. Deposition of micron liquid droplets on wall in impinging turbulent air jet

    Science.gov (United States)

    Liu, Tianshu; Nink, Jacob; Merati, Parviz; Tian, Tian; Li, Yong; Shieh, Tom

    2010-06-01

    The fluid mechanics of the deposition of micron liquid (olive oil) droplets on a glass wall in an impinging turbulent air jet is studied experimentally. The spatial patterns of droplets deposited on a wall are measured by using luminescent oil visualization technique, and the statistical data of deposited droplets are obtained through microscopic imagery. Two distinct rings of droplets deposited on a wall are found, and the mechanisms of the formation of the inner and outer rings are investigated based on global diagnostics of velocity and skin friction fields. In particular, the intriguing effects of turbulence, including large-scale coherent vortices and small-scale random turbulence, on micron droplet deposition on a wall and coalescence in the air are explored.

  8. Iodine Removal Efficiency in Non-Submerged and Submerged Self-Priming Venturi Scrubber

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Majid; Yan, Changqi; Sun, Zhongning; Gu, Haifeng; Wang, Junlong; Mehboob; Khurram [Harbin Engineering Univ., Harbin (China)

    2013-04-15

    The objective of this conducted research is to study the iodine removal efficiency in a self-priming venturi scrubber for submerged and non-submerged operating conditions experimentally and theoretically. The alkaline solution is used as an absorbent, which is prepared by dissolving sodium hydroxide (NaOH) and sodium thiosulphate (Na{sub 2}S{sub 2}O{sub 3}) in water to remove the gaseous iodine (I{sub 2}) from the gas. Iodine removal efficiency is examined at various gas flow rates and inlet concentrations of iodine for submerged and non-submerged operating conditions. In the non-submerged venturi scrubber, only the droplets take part in iodine removal efficiency. However, in a submerged venturi scrubber condition, the iodine gas is absorbed from gas to droplets inside the venturi scrubber and from bubbles to surrounding liquid at the outlet of a venturi scrubber. Experimentally, it is observed that the iodine removal efficiency is greater in the submerged venturi scrubber as compare to a non-submerged venturi scrubber condition. The highest iodine removal efficiency of 0.99±0.001 has been achieved in a submerged self-priming venturi scrubber condition. A mathematical correlation is used to predict the theoretical iodine removal efficiency in submerged and non-submerged conditions, and it is compared against the experimental results. The Wilkinson et al. correlation is used to predict the bubble diameter theoretically whereas the Nukiyama and Tanasawa correlation is used for droplet diameter. The mass transfer coefficient for the gas phase is calculated from the Steinberger and Treybal correlation. The calculated results for a submerged venturi scrubber agree well with experimental results but underpredicts in the case of the non-submerged venturi scrubber.

  9. IODINE REMOVAL EFFICIENCY IN NON-SUBMERGED AND SUBMERGED SELF-PRIMING VENTURI SCRUBBER

    Directory of Open Access Journals (Sweden)

    MAJID ALI

    2013-04-01

    Full Text Available The objective of this conducted research is to study the iodine removal efficiency in a self-priming venturi scrubber for submerged and non-submerged operating conditions experimentally and theoretically. The alkaline solution is used as an absorbent, which is prepared by dissolving sodium hydroxide (NaOH and sodium thiosulphate (Na2S2O3 in water to remove the gaseous iodine (I2 from the gas. Iodine removal efficiency is examined at various gas flow rates and inlet concentrations of iodine for submerged and non-submerged operating conditions. In the non-submerged venturi scrubber, only the droplets take part in iodine removal efficiency. However, in a submerged venturi scrubber condition, the iodine gas is absorbed from gas to droplets inside the venturi scrubber and from bubbles to surrounding liquid at the outlet of a venturi scrubber. Experimentally, it is observed that the iodine removal efficiency is greater in the submerged venturi scrubber as compare to a non-submerged venturi scrubber condition. The highest iodine removal efficiency of 0.99±0.001 has been achieved in a submerged self-priming venturi scrubber condition. A mathematical correlation is used to predict the theoretical iodine removal efficiency in submerged and non-submerged conditions, and it is compared against the experimental results. The Wilkinson et al. correlation is used to predict the bubble diameter theoretically whereas the Nukiyama and Tanasawa correlation is used for droplet diameter. The mass transfer coefficient for the gas phase is calculated from the Steinberger and Treybal correlation. The calculated results for a submerged venturi scrubber agree well with experimental results but underpredicts in the case of the non-submerged venturi scrubber.

  10. High-power liquid-lithium jet target for neutron production.

    Science.gov (United States)

    Halfon, S; Arenshtam, A; Kijel, D; Paul, M; Berkovits, D; Eliyahu, I; Feinberg, G; Friedman, M; Hazenshprung, N; Mardor, I; Nagler, A; Shimel, G; Tessler, M; Silverman, I

    2013-12-01

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the (7)Li(p,n)(7)Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm(3)) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the (7)Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ~200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm(2) and volume power density of ~2 MW/cm(3) at a lithium flow of ~4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91-2.5 MeV, 1-2 mA) at SARAF.

  11. High-power liquid-lithium jet target for neutron production

    Energy Technology Data Exchange (ETDEWEB)

    Halfon, S.; Feinberg, G. [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Arenshtam, A.; Kijel, D.; Berkovits, D.; Eliyahu, I.; Hazenshprung, N.; Mardor, I.; Nagler, A.; Shimel, G.; Silverman, I. [Soreq NRC, Yavne 81800 (Israel); Paul, M.; Friedman, M.; Tessler, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

    2013-12-15

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the {sup 7}Li(p,n){sup 7}Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm{sup 3}) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the {sup 7}Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ∼200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm{sup 2} and volume power density of ∼2 MW/cm{sup 3} at a lithium flow of ∼4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91–2.5 MeV, 1–2 mA) at SARAF.

  12. US State Submerged Lands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Submerged Lands Act (43 U.S.C. Section 1301 et seq.) grants coastal states title to natural resources located within their coastal submerged lands and navigable...

  13. Probing orbital symmetry in solution: polarization-dependent resonant inelastic soft x-ray scattering on liquid micro-jet

    Science.gov (United States)

    Dierker, B.; Suljoti, E.; Atak, K.; Lange, K. M.; Engel, N.; Golnak, R.; Dantz, M.; Hodeck, K.; Khan, M.; Kosugi, N.; Aziz, E. F.

    2013-09-01

    Polarization-dependent resonant inelastic x-ray scattering is demonstrated here for liquid acetonitrile, acetone and dimethyl sulfoxide, using the liquid micro-jet technique. Selective excitation to an unoccupied orbital with a specific symmetry at the K-edge x-ray absorption of liquid samples determines the polarization-dependent emission of the occupied states. Considering the well-defined unoccupied molecular orbital configuration and utilizing the results of ab initio molecular orbital calculations, the polarization-dependent anisotropy in resonant inelastic soft x-ray scattering is discussed in a membrane-free configuration.

  14. A ballistic compressor-based experiment for the visualization of liquid propellant jet combustion above 100 MPa

    Science.gov (United States)

    Birk, A.; Kooker, D. E.

    This paper describes the components and operation of an experimental setup for the visualization of liquid propellant (LP) jet combustion at pressures above 100 MPa. The apparatus consists of an in-line ballistic compressor and LP injector. The ballistic compressor, based on a modified 76 mm gun, provides high-pressure (ca. 55 MPa) clear hot gas for the jet ignition. A piston (projectile) is fired toward a test chamber beyond the barrel's end, and its rebound is arrested in a transition section that seals the test chamber to the barrel. The LP jet is injected once the piston is restrained, and combustion of the jet further elevates the pressure. At a preset pressure, a disc in the piston ruptures and the combustion gas vents sonically into the barrel. If a monopropellant is used, the jet injection-combustion process then resembles liquid rocket combustion but at very high pressures (ca. 140 MPa). This paper discusses the ballistics of the compression and compares experimental results to those predicted by a numerical model of the apparatus. Experimentally, a pressure of 70 MPa was achieved upon a 12.5 volumetric compression factor by firing a 10 kg piston into 1.04 MPa argon using a charge of 75 g of small-grain M1 propellant.

  15. Non-thermal processes on ice and liquid micro-jet surfaces

    Science.gov (United States)

    Olanrewaju, Babajide O.

    The primary focus of this research is to investigate non-thermal processes occurring on ice surfaces and the photo-ejection of ions from liquid surfaces. Processes at the air-water/ice interface are known to play a very important role in the release of reactive halogen species with atmospheric aerosols serving as catalysts. The ability to make different types of ice with various morphologies, hence, different adsorption and surface properties in vacuum, provide a useful way to probe the catalytic effect of ice in atmospheric reactions. Also, the use of the liquid jet technique provides the rare opportunity to probe liquid samples at the interface; hitherto impossible to investigate with traditional surface science techniques. In Chapter 2, the effect of ice morphology on the release of reactive halogen species from photodissociation of adsorbed organic halides on ice will be presented. Quantum state resolved measurements of neutral atomic iodine from the photon irradiation of submonolayer coverages of methyl iodide adsorbed on low temperature water ice were conducted. Temperature programmed desorption (TPD) studies of methyl iodide adsorbed on ice were performed to provide information on the effect of ice morphology on the adsorption of submonolayer methyl iodide. The interaction and autoionization of HCl on low-temperature (80{140 K) water ice surfaces has been studied using low-energy (5-250 eV) electron-stimulated desorption (ESD) and temperature programmed desorption (TPD). A detailed ESD study of the interactions of low concentrations of HCl with low-temperature porous amorphous solid water (PASW), amorphous solid water (ASW) and crystalline ice (CI) surfaces will be presented in Chapter 3. The ESD cation yields from HCl adsorbed on ice, as well as the coverage dependence, kinetic energy distributions and TPD measurements were all monitored. Probing liquid surface using traditional surface science technique is usually difficult because of the problem of

  16. Measurement of changes in respiratory mechanics during partial liquid ventilation using jet pulses.

    Science.gov (United States)

    Schmalisch, Gerd; Schmidt, Mario; Proquitté, Hans; Foitzik, Bertram; Rüdiger, Mario; Wauer, Roland R

    2003-05-01

    To compare the changes in respiratory mechanics within the breathing cycle in healthy lungs between gas ventilation and partial liquid ventilation using a special forced-oscillation technique. Prospective animal trial. Animal laboratory in a university setting. A total of 12 newborn piglets (age, mechanics of the anesthetized piglets were measured by forced-oscillation technique at the end of inspiration and the end of expiration. The measurements were performed during gas ventilation and 80 mins after instillation of 30 mL/kg perfluorocarbon PF 5080. Brief flow pulses (width, 10 msec; peak flow, 16 L/min) were generated by a jet generator to measure the end-inspiratory and the end-expiratory respiratory input impedance in the frequency range of 4-32 Hz. The mechanical variables resistance, inertance, and compliance were determined by model fitting, using the method of least squares. At least in the lower frequency range, respiratory mechanics could be described adequately by an RIC single-compartment model in all piglets. During gas ventilation, the respiratory variables resistance and inertance did not differ significantly between end-inspiratory and end-expiratory measurements (mean [sd]: 4.2 [0.7] vs. 4.1 [0.6] kPa x L(-1) x sec, 30.0 [3.2] vs. 30.7 [3.1] Pa x L(-1) x sec2, respectively), whereas compliance decreased during inspiration from 14.8 (2.0) to 10.2 (2.4) mL x kPa(-1) x kg(-1) due to a slight lung overdistension. During partial liquid ventilation, the end-inspiratory respiratory mechanics was not different from the end-inspiratory respiratory mechanics measured during gas ventilation. However, in contrast to gas ventilation during partial liquid ventilation, compliance rose from 8.2 (1.0) to 13.0 (3.0) mL x kPa(-1) x kg(-1) during inspiration. During expiration, when perfluorocarbon came into the upper airways, both resistance and inertance increased considerably (mean with 95% confidence interval) by 34.3% (23.1%-45.8%) and 104.1% (96

  17. Multi-fluid Dynamics for Supersonic Jet-and-Crossflows and Liquid Plug Rupture

    Science.gov (United States)

    Hassan, Ezeldin A.

    Multi-fluid dynamics simulations require appropriate numerical treatments based on the main flow characteristics, such as flow speed, turbulence, thermodynamic state, and time and length scales. In this thesis, two distinct problems are investigated: supersonic jet and crossflow interactions; and liquid plug propagation and rupture in an airway. Gaseous non-reactive ethylene jet and air crossflow simulation represents essential physics for fuel injection in SCRAMJET engines. The regime is highly unsteady, involving shocks, turbulent mixing, and large-scale vortical structures. An eddy-viscosity-based multi-scale turbulence model is proposed to resolve turbulent structures consistent with grid resolution and turbulence length scales. Predictions of the time-averaged fuel concentration from the multi-scale model is improved over Reynolds-averaged Navier-Stokes models originally derived from stationary flow. The response to the multi-scale model alone is, however, limited, in cases where the vortical structures are small and scattered thus requiring prohibitively expensive grids in order to resolve the flow field accurately. Statistical information related to turbulent fluctuations is utilized to estimate an effective turbulent Schmidt number, which is shown to be highly varying in space. Accordingly, an adaptive turbulent Schmidt number approach is proposed, by allowing the resolved field to adaptively influence the value of turbulent Schmidt number in the multi-scale turbulence model. The proposed model estimates a time-averaged turbulent Schmidt number adapted to the computed flowfield, instead of the constant value common to the eddy-viscosity-based Navier-Stokes models. This approach is assessed using a grid-refinement study for the normal injection case, and tested with 30 degree injection, showing improved results over the constant turbulent Schmidt model both in mean and variance of fuel concentration predictions. For the incompressible liquid plug propagation

  18. Investigation of the impact of high liquid viscosity on jet atomization in crossflow via high-fidelity simulations

    Science.gov (United States)

    Li, Xiaoyi; Gao, Hui; Soteriou, Marios C.

    2017-08-01

    Atomization of extremely high viscosity liquid can be of interest for many applications in aerospace, automotive, pharmaceutical, and food industries. While detailed atomization measurements usually face grand challenges, high-fidelity numerical simulations offer the advantage to comprehensively explore the atomization details. In this work, a previously validated high-fidelity first-principle simulation code HiMIST is utilized to simulate high-viscosity liquid jet atomization in crossflow. The code is used to perform a parametric study of the atomization process in a wide range of Ohnesorge numbers (Oh = 0.004-2) and Weber numbers (We = 10-160). Direct comparisons between the present study and previously published low-viscosity jet in crossflow results are performed. The effects of viscous damping and slowing on jet penetration, liquid surface instabilities, ligament formation/breakup, and subsequent droplet formation are investigated. Complex variations in near-field and far-field jet penetrations with increasing Oh at different We are observed and linked with the underlying jet deformation and breakup physics. Transition in breakup regimes and increase in droplet size with increasing Oh are observed, mostly consistent with the literature reports. The detailed simulations elucidate a distinctive edge-ligament-breakup dominated process with long surviving ligaments for the higher Oh cases, as opposed to a two-stage edge-stripping/column-fracture process for the lower Oh counterparts. The trend of decreasing column deflection with increasing We is reversed as Oh increases. A predominantly unimodal droplet size distribution is predicted at higher Oh, in contrast to the bimodal distribution at lower Oh. It has been found that both Rayleigh-Taylor and Kelvin-Helmholtz linear stability theories cannot be easily applied to interpret the distinct edge breakup process and further study of the underlying physics is needed.

  19. Steady high viscosity liquid micro-jet production and fiber spinning using co-flowing gas conformation

    Science.gov (United States)

    Gañán-Calvo, A. M.; Pérez-Saborid, M.; López-Herrera, J. M.; Gordillo, J. M.

    2004-05-01

    Here we propose a new physical approach to the high-speed conformation of a Newtonian viscous liquid into a fiber (high speed fiber drawing), which suppresses all well-known axisymmetric and asymmetric instabilities during the fiber drawing. Our approach is based on the application of an appropriate gas pressure profile along the viscous jet or fiber axis, provided by a special subsonic micro-nozzle concentric with the fiber. The micro-nozzle design and optimization is mathematically provided.

  20. Very-near-field dynamics in the injection of two-dimensional gas jets and thin liquid sheets between two parallel high-speed gas streams

    OpenAIRE

    López-Pagés, Enrique; Dopazo, C.; Fueyo, Norberto

    2004-01-01

    A numerical investigation of the velocity, pressure and vorticity fields very near the injection of flat and thin two-dimensional gas jets or liquid sheets between two parallel high-speed gas coflows is performed. The motivation of this research is to uncover some basic physical mechanisms underlying twin-fluid atomization. Conservation equations and boundary and initial conditions are presented for both single-phase jets and two-phase liquid sheet/gas-stream systems. Both infinitely thin and...

  1. Image analysis of jet structure on electrospinning from free liquid surface

    Energy Technology Data Exchange (ETDEWEB)

    Kula, Jiri, E-mail: jiri.kula@tul.cz; Linka, Ales, E-mail: ales.linka@tul.cz; Tunak, Maros, E-mail: maros.tunak@tul.cz [Department of Textile Evaluation, Faculty of Textile Engineering, Technical University of Liberec, Studentska 2, 461 17 Liberec (Czech Republic); Lukas, David, E-mail: david.lukas@tul.cz [Department of Nonwoven and Nanofibrous Materials, Faculty of Textile Engineering, Technical University of Liberec, Studentska 2, 461 17 Liberec (Czech Republic); Centre for Nanomaterials Advanced Technologies and Innovation, Technical University of Liberec, Studentska 2, 461 17 Liberec (Czech Republic)

    2014-06-16

    The work analyses intra-jet distances during electrospinning from a free surface of water based poly(vinyl alcohol) solution confined by two thin metallic plates employed as a spinning electrode. A unique computer vision system and digital image processing were designed in order to track position of every polymer jet. Here, we show that jet position data are in good compliance with theoretically predicted intra-jet distances by linear stability analysis. Jet density is a critical parameter of electrospinning technology, since it determines the process efficiency and homogeneity of produced nanofibrous layer. Achievements made in this research could be used as essential approach to study jetting from two-dimensional spinning electrodes, or as fundamentals for further development of control system related to Nanospider{sup ™} technology.

  2. Modeling Single-Phase and Boiling Liquid Jet Impingement Cooling in Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, S. V. J.; Hassani, V.; Bharathan, D.

    2005-12-01

    Jet impingement has been an attractive cooling option in a number of industries over the past few decades. Over the past 15 years, jet impingement has been explored as a cooling option in microelectronics. Recently, interest has been expressed by the automotive industry in exploring jet impingement for cooling power electronics components. This technical report explores, from a modeling perspective, both single-phase and boiling jet impingement cooling in power electronics, primarily from a heat transfer viewpoint. The discussion is from the viewpoint of the cooling of IGBTs (insulated-gate bipolar transistors), which are found in hybrid automobile inverters.

  3. Advanced Liquid Cooling for a Traction Drive Inverter Using Jet Impingement and Microfinned Enhanced Surfaces: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S. K.; Narumanchi, S.; Mihalic, M.; Moreno, G.; Bennion, K.; Jeffers, J.

    2014-08-01

    Jet impingement on plain and micro-finned enhanced surfaces was compared to a traditional channel flow configuration. The jets provide localized cooling to areas heated by the insulated-gate bipolar transistor and diode devices. Enhanced microfinned surfaces increase surface area and thermal performance. Using lighter materials and designing the fluid path to manage pressure losses increases overall performance while reducing weight, volume, and cost. Powering four diodes in the center power module of the inverter and computational fluid dynamics (CFD) modeling was used to characterize the baseline as well as jet-impingement-based heat exchangers. CFD modeling showed the thermal performance improvements should hold for a fully powered inverter. Increased thermal performance was observed for the jet-impingement configurations when tested at full inverter power (40 to 100 kW output power) on a dynamometer. The reliability of the jets and enhanced surfaces over time was also investigated. Experimentally, the junction-to- coolant thermal resistance was reduced by up to 12.5% for jet impingement on enhanced surfaces s compared to the baseline channel flow configuration. Base plate-to-coolant (convective) resistance was reduced by up to 37.0% for the jet-based configuration compared to the baseline, suggesting that while improvements to the cooling side reduce overall resistance, reducing the passive stack resistance may contribute to lowering overall junction-to-coolant resistance. Full inverter power testing showed reduced thermal resistance from the middle of the module baseplate to coolant of up to 16.5%. Between the improvement in thermal performance and pumping power, the coefficient of performance improved by up to 13% for the jet-based configuration.

  4. Visualization of laser-induced liquid micro-jet disintegration by means of high-speed video stroboscopy

    Science.gov (United States)

    Stasicki, Boleslaw; Charvat, Ales; Faubel, Manfred; Abel, Bernd

    2005-03-01

    In the present paper we describe a novel approach to monitor and to investigate laser induced liquid water jet disintegration in air and in vacuum. The features of liquid beam disintegration in vacuum are of importance for pulsed laser induced liquid beam desorption mass spectrometry and micro-calorimetry. Due to the small liquid beam diameter of 12-15 μm, its high speed of 50-100 m/s, and a total event duration of a less than a few microseconds only, the microscopic visualization of the jet disintegration was a challenging task. Good quality video sequences have been recorded with a high-speed video stroboscope system running in the back illumination mode. The light pulses were synchronized carefully with the shutter circuit of the stroboscope camera and the IR-laser pulses. With a continuously changing time delay between the desorption laser pulses and the shutter opening a slow-motion effect has been achieved. The delay was changed in steps of 25 ns which corresponds to an equivalent framing speed of about 40,000,000 fps. With a high-brightness light emitting diode (LED) as a light source an exposure time of about 200 ns an effective time resolution of several hundred nanoseconds could be achieved. Using a pulsed Nd:YAG laser instead, the exposure time and time resolution could be reduced down to about 10 ns and 25 ns, respectively. Due to the well known speckle problem when using coherent light sources for illumination we have finally used a Nd:YAG laser excited dye solution of Rhodamine 6G (10-3 M) in methanol solution in a quartz cuvette placed in front of the liquid beam keeping the short exposure time of about 10 ns. In this nearly speckle free visualization mode the real-time slow-motion imaging of the jet disintegration and the study of the desorption process has been made possible with a time resolution of 25 ns (currently limited by the phase shifter steps) and an exposure time of ~10 ns only. It has been found that the laser induced desorption is so

  5. Spray Formation from a Charged Liquid Jet of a Dielectric Fluid

    Science.gov (United States)

    Doak, William; de Bellis, Victor; Chiarot, Paul; Microfluidics; Multiphase Flow Laboratory Team

    2017-11-01

    Atomization of a dielectric micro-jet is achieved via an electrohydrodynamic charge injection process. The atomizer is comprised of a grounded nozzle housing (ground electrode) and an internal probe (high voltage electrode) that is concentric with the emitting orifice. The internal probe is held at electric potentials ranging from 1-10 kV. A pressurized reservoir drives a dielectric fluid at a desired flow rate through the 100-micrometer diameter orifice. The fluid fills the cavity between the electrodes as it passes through the atomizer, impeding the transport of electrons. This process injects charge into the flowing fluid. Upon exiting the orifice, the emitted jet is highly charged and it deforms via a bending instability that is qualitatively similar to the behavior observed in the electrospinning of fibers. We observed bulging regions, or nodes, of highly charged fluid forming along the bent, rotating jet. These nodes separate into highly charged droplets that emit satellite droplets. The remaining ligaments break up due to capillarity in a process that produces additional satellites. All of the droplets possess a normal (inertial) and radial (electrically-driven) momentum component. The radial component is responsible for the formation of a conical spray envelope. Our research focuses on the jet, its break up, and the droplet dynamics of this system. This research supported by the American Chemical Society.

  6. The effect of turbulence on the stability of liquid jets and the resulting droplet size distributions. Third quarterly technical report, July 1, 1993--September 30, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Mansour, A.; Chigier, N.

    1993-12-01

    Laminar and turbulent columns of liquids issuing from capillary tubes were studied in order to determine the effects of turbulence on the stability of liquid jets and to establish the influence of liquid turbulence on droplet size distributions after breakup. Two capillary tubes were chosen with diameters D{sub 1}=3.0mm and D{sub 2}=1.2mm; jet Reynolds numbers were 1000--30000, and 400--7200. For water injection into stagnant air, stability curve is bounded by a laminar portion, where a jet radius and {delta}{sub o} initial disturbance amplitude, and a fully developed turbulent portion characterized by high initial disturbance amplitude (ln(a/{delta}{sub o,T}) {approximately} 4.85). In the transition region, ln(a/{delta}{sub o}) is not single valued; it decreases with increasing Reynolds number. In absence of aerodynamic effects, turbulent jets are as stable as laminar jets. For this breakup mode turbulence propagates initial disturbances with amplitudes orders of magnitude larger than laminar jets ({delta}{sub o,T}=28{times}10{sup 6} {delta}{sub o,L}). Growth rates of initial disturbances are same for both laminar and turbulent columns with theoretical Weber values. Droplet size distribution is bi-modal; the number ratio of large (> D/2), to small (< D/2) droplets is 3 and independent of Reynolds number. For laminar flow optimum wavelength ({lambda}{sub opt}) corresponding to fastest growing disturbance is equal to 4.45D, exactly the theoretical Weber value. For turbulent flow conditions, the turbulent column segments. Typically, segments with lengths of one to several wavelengths, detach from the liquid jet. The long ligaments contract under the action of surface tension, resulting in droplet sizes larger than predicted by Rayleigh and Weber. For turbulent flow conditions, {lambda}{sub opt} = 9.2D, about 2 times the optimum Weber wavelength.

  7. Instability evolution of the viscous elliptic liquid jet in the Rayleigh regime

    Science.gov (United States)

    Gu, Shibo; Wang, Lipo; Hung, David L. S.

    2017-06-01

    For jet flow emanating from noncircular orifices, an unbalanced surface tension force leads to capillary instability, which is independent of influence from the ambient air in the Rayleigh regime. In the present article, the dynamic behavior of incompressible elliptical jets in the Rayleigh regime is investigated. Theoretically, with the consideration of the fluid viscosity, the solution of the Cosserat equation consists of a particular solution and a complementary solution. For the complementary solution the wave number of disturbance modes has two complex conjugate roots, which are responsible for the jet breakup. To match the nonzero particular solution, a spatial wave needs to be introduced, which is independent of external perturbations. Physically, such a spatial wave is interpreted as the axis-switching phenomenon. The predicted features of the axis-switching wavelength and the damping effect from the fluid viscosity have been successfully verified by experimental results. Moreover, the dispersion relations from the present theory suggest that the growth rate of spatial instability is influenced by orifice eccentricity, the Weber number, and the Ohnesorge number.

  8. Cars submerged in water.

    NARCIS (Netherlands)

    2010-01-01

    Crashes in which cars are submerged in deep water or in a ditch are often complicated and serious. Considering their severity and the fact that approximately half the fatalities in this crash type are not due to drowning but to injury, preventive measures are to be preferred above measures that have

  9. The use of pulsed high-speed liquid jet for putting out gas blow-out

    Directory of Open Access Journals (Sweden)

    A Semko

    2016-10-01

    Full Text Available The experimental analysis of putting out a gas blow-out with the help of pulse liquid flow with high velocity, which generates by powder pulse water-cannon are carried out. The flow velocity resides in range from 300 to 600 m/s in experiments depends on charge energy. Velocity of the flow head right near the gas flame determined with the help of laser contactless measuring instrument of velocity. Photography of flow was carried out. According to the preliminary test results the hydrodynamic parameters of powder pulse water-cannon for obtaining liquid flow with depend velocity are calculated. It is shown, that around the liquid flow of high velocity in air produced fine water spray with high velocity in large cross section area that effective knock down the gas blow-out at the distance 5-20 m from installation.

  10. Dual pulse laser induced breakdown spectroscopy on Cu concentration in CuSO4 solution with liquid jet

    Science.gov (United States)

    Zhang, Yawei; Gao, Xun; Zhu, Hongbo; Han, Jinliang

    2017-10-01

    Laser induced breakdown spectroscopy (LIBS) is a promising technique, analyzing spectrum of plasma, to detect elements of solid, liquid or gaseous samples. It has many advantages, including in-situ and online detection, remote analysis, non-preparation of samples, and simultaneously multi-elements detection. Aiming at detecting detrimental elements in the polluted river and water, in this paper, collinear dual-pulse (DP) Laser-induced breakdown spectroscopy (LIBS) with liquid jet was employed to analyze emission spectrum of Cu element in the CuSO4 solution. We investigated the effect of laser pulse energies ratio and time delay between two lasers on signal intensity, which were simply given by theoretical model in laser-induced plasma for explaining various behaviors of emission spectrum. It was inferred that the maximum signal enhancement of DP-LIBS experiment was roughly 4.5 times greater than that of SP case. The limit of detection (LOD) of Cu using DP-LIBS was approximately 15 times lower than that of SP-LIBS. Results of this research indicate that collinear DP-LIBS is an effective approach to improve the plasma emission intensity and reduce the value of LOD, the application of which can be considered into the environmental problem of the water pollution.

  11. Modelling of the liquid slag behaviour in the continuous casting mould

    OpenAIRE

    Kountouriotis, Zacharias

    2011-01-01

    This work presents a fluid dynamics model of a continuous caster mould region, including the transient behaviour of the steel/slag interface. The research was carried out in collaboration with ArcelorMittal Research (AMR), based in Maizieres-les-Metz in France. The industrial objective of the thesis was to understand the factors affecting the transient behaviour of the liquid slag layer covering the steel and its interaction with the Submerged Entry Nozzle (SEN) jet supplying the steel from t...

  12. Mean droplet size and local velocity in horizontal isothermal free jets of air and water, respectively, viscous liquid in quiescent ambient air

    Energy Technology Data Exchange (ETDEWEB)

    Al Rabadi, S.; Friedel, L. [Fluid Mechanics Institute, Technical University of Hamburg-Harburg (Germany); Al Salaymeh, A. [Mechanical Engineering Department, University of Jordan (Jordan)

    2007-01-15

    Measurements using two-dimensional Phase Doppler Anemometry as well as high speed cinematography in free jets at several nozzle exit pressures and mass flow rates, show that the Sauter mean droplet diameter decreases with increasing air and liquid-phase mass flow ratio due to the increase of the air stream impact on the liquid phase. This leads to substantial liquid fragmentation, respectively primary droplet breakup, and hence, satellite droplet formation with small sizes. This trend is also significant in the case of a liquid viscosity higher than that of water. The increased liquid viscosity stabilizes the droplet formation and breakup by reducing the rate of surface perturbations and consequently droplet distortions, ultimately also leading, in total, to the formation of smaller droplets. The droplet velocity decreases with the nozzle downstream distance, basically due to the continual air entrainment and due to the collisions between the droplets. The droplet collisions may induce further liquid fragmentation and, hence, formation of a number of relatively smaller droplets respectively secondary breakup, or may induce agglomeration to comparatively larger liquid fragments that may rain out of the free jet. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  13. Three dimensional ink-jet printing of biomaterials using ionic liquids and co-solvents.

    Science.gov (United States)

    Gunasekera, Deshani H A T; Kuek, SzeLee; Hasanaj, Denis; He, Yinfeng; Tuck, Christopher; Croft, Anna K; Wildman, Ricky D

    2016-08-15

    1-Ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) and 1-butyl-3-methylimidazolium acetate ([C4C1Im][OAc]) have been used as solvents for the dissolution and ink-jet printing of cellulose from 1.0 to 4.8 wt%, mixed with the co-solvents 1-butanol and DMSO. 1-Butanol and DMSO were used as rheological modifiers to ensure consistent printing, with DMSO in the range of 41-47 wt% producing samples within the printable range of a DIMATIX print-head used (printability parameter printed samples using water was demonstrated, with the resulting structural changes to the cellulose sample assessed by scanning electron microscopy (SEM) and white light interferometry (WLI). These results indicate the potential of biorenewable materials to be used in the 3D additive manufacture process to generate single-component and composite materials.

  14. Microbial Inactivation in the Liquid Phase Induced by Multigas Plasma Jet.

    Directory of Open Access Journals (Sweden)

    Toshihiro Takamatsu

    Full Text Available Various gas atmospheric nonthermal plasmas were generated using a multigas plasma jet to treat microbial suspensions. Results indicated that carbon dioxide and nitrogen plasma had high sterilization effects. Carbon dioxide plasma, which generated the greatest amount of singlet oxygen than other gas plasmas, killed general bacteria and some fungi. On the other hand, nitrogen plasma, which generated the largest amount of OH radical, killed ≥ 6 log of 11 species of microorganisms, including general bacteria, fungi, acid-fast bacteria, spores, and viruses in 1-15 min. To identify reactive species responsible for bacterial inactivation, antioxidants were added to bacterial suspensions, which revealed that singlet oxygen and OH radicals had greatest inactivation effects.

  15. Flashing liquid jets and two-phase droplet dispersion I. Experiments for derivation of droplet atomisation correlations.

    Science.gov (United States)

    Cleary, Vincent; Bowen, Phil; Witlox, Henk

    2007-04-11

    The large-scale release of a liquid contained at upstream conditions above its local atmospheric boiling point is a scenario often given consideration in process industry risk analysis. Current-hazard quantification software often employs simplistic equilibrium two-phase approaches. Scaled water experiments have been carried out measuring droplet velocity and droplet size distributions for a range of exit orifice aspect ratios (L/d) and conditions representing low to high superheat. 2D Phase-Doppler Anemometry has been utilised to characterise droplet kinematics and spray quality. Droplet size correlations have been developed for non-flashing, the transition between non-flashing and flashing, and fully flashing jets. Using high-speed shadowography, transition between regimes is defined in terms of criteria identified in the external flow structure. An overview companion paper provides a wider overview of the problem and reports implementation of these correlations into consequence models and subsequent validation. The fluid utilised throughout is water, hence droplet correlations are developed in non-dimensional form to allow extrapolation to other fluids through similarity scaling, although verification of model performance for other fluids is required in future studies. Data is reduced via non-dimensionalisation in terms of the Weber number and Jakob number, essentially representing the fluid mechanics and thermodynamics of the system, respectively. A droplet-size distribution correlation has also been developed, conveniently presented as a volume undersize distribution based on the Rosin-Rammler distribution. Separate correlations are provided for sub-cooled mechanical break-up and fully flashing jets. This form of correlation facilitates rapid estimates of likely mass rainout quantities, as well as full distribution information for more rigorous two-phase thermodynamic modelling in the future.

  16. Augmentation of Critical Heat Flux of High Velocity Liquid Jet Flow utilizing Flat-Narrow Rectangular Channel

    Science.gov (United States)

    Sakurai, Hisashi; Koizumi, Yasuo; Ohtake, Hiroyasu

    Sub-cooled flow boiling heat transfer experiments were performed for narrow-flat flow passages of 2 mm wide and 0.2 mm high. A heat transfer surface of 2 mm × 2 mm was placed at the just downstream of the flow channel outlet. A fast wall plane-jet was formed on the heat transfer surface and space for vapor generated on the heat transfer surface to leave freely form the plane jet was provided The experiments covered the flow rate from 5 m⁄s through 20 m⁄s and the inlet sub-cooling from 30 K through 70 K. Critical heat fluxes were greatly augmented about twice compared with those in the previous experiments where the heat transfer surface was located at the outlet end of the same flow channel as that in the present experiments. This has indicated that the present idea of the flow system is effective to enhance the critical heat flux. When the flow velocity was slower than 10 m⁄s, a large secondary bubble that was formed as a result of coalescence of many primary bubbles on the heat transfer surface covered the heat transfer surface. The large-coalesced bubble triggered the occurrence of the critical heat flux. When the flow velocity became faster than 10 m⁄s, the heat transfer surface was covered with many tiny-primary bubbles even at the critical heat flux condition. The critical heat fluxes in the present experiments were much larger than predictions of correlations. The triggering mechanism of the critical heat flux condition was proposed based on the observation mentioned above. It has two parts; for low flow velocity and for high flow velocity. The boundary is 10 m⁄s. In both cases, disappearance of a liquid film under the bubble due to evaporation is related to the appearance of the critical heat flux condition. The predicted critical heat fluxes were larger than that measured, however, qualitatively agreed well.

  17. Simple and Reproducible Two-Stage Agitation Speed Control Strategy for Enhanced Triterpene Production by Lingzhi or Reishi Medicinal Mushrooms, Ganoderma lucidum ACCC G0119 (Higher Basidiomycetes) Based on Submerged Liquid Fermentation.

    Science.gov (United States)

    Feng, Jie; Feng, Na; Yang, Yan; Liu, Fang; Zhang, Jingsong; Jia, Wei; Lin, Chi-Chung

    2015-01-01

    Triterpenes are important anticancer agents produced by batch submerged liquid fermentation, with the medicinal mushroom Ganoderma lucidum ACCC G0119, which was investigated under various dissolved oxygen levels by varying agitation speeds. Three kinetic parameters were analyzed: specific mycelial growth rate (μsmg), specific glucose consumption rate (qsgc), and specific triterpene production rate (qstp). High concentration, yield, and productivity of triterpenes were achieved by developing a simple and reproducible two-stage agitation speed control strategy. At the first 40 h, agitation speed was controlled at 150 rpm to obtain the quickest peak qstp for triterpene production, subsequently agitation speed was controlled at 100 rpm to maintain high qstp for high triterpene accumulation. The maximum concentration of triterpenes reached 0.086 g/l with the yield of 6.072 g/kg and the productivity of 6.532 × 10-4 g/(l·h), which were 39.61%, 36.48%, and 49.22%, respectively, better than the best results controlled by fixed agitation speeds. Conceivably, such a triterpene fermentation production strategy would be useful for industrial large-scale production of triterpenes with G. lucidum.

  18. Measurement of Submerged Oil/Gas Leaks using ROV Video

    Science.gov (United States)

    Shaffer, Franklin; de Vera, Giorgio; Lee, Kenneth; Savas, Ömer

    2013-11-01

    Drilling for oil or gas in the Gulf of Mexico is increasing rapidly at depths up to three miles. The National Commission on the Deepwater Horizon Oil Leak concluded that inaccurate estimates of the leak rate from the Deepwater Horizon caused an inadequate response and attempts to cap the leak to fail. The first response to a submerged oil/gas leak will be to send a Remotely Operated Vehicle (ROV) down to view the leak. During the response to the Deepwater Horizon crisis, the authors Savas and Shaffer were members of the Flow Rate Technical Group's Plume Team who used ROV video to develop the FRTG's first official estimates of the oil leak rate. Savas and Shaffer developed an approach using the larger, faster jet features (e.g., turbulent eddies, vortices, entrained particles) in the near-field developing zone to measure discharge rates. The authors have since used the Berkeley Tow Tank to test this approach on submerged dye-colored water jets and compressed air jets. Image Correlation Velocimetry has been applied to measure the velocity of visible features. Results from tests in the Berkeley Tow Tank and submerged oil jets in the OHMSETT facility will be presented.

  19. Application of atmospheric-pressure plasma jet processed carbon nanotubes to liquid and quasi-solid-state gel electrolyte supercapacitors

    Science.gov (United States)

    Kuok, Fei-Hong; Kan, Ken-Yuan; Yu, Ing-Song; Chen, Chieh-Wen; Hsu, Cheng-Che; Cheng, I.-Chun; Chen, Jian-Zhang

    2017-12-01

    We use a dc-pulse nitrogen atmospheric-pressure plasma jet (APPJ) to calcine carbon nanotubes (CNTs) pastes that are screen-printed on carbon cloth. 30-s APPJ treatment can efficiently oxidize and vaporize the organic binders, thereby forming porous structures. As indicated by X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA), the oxygen content decreases after APPJ treatment owing to the oxidation and vaporization of ethyl cellulose, terpineol, and ethanol. Nitrogen doping was introduced to the materials by the nitrogen APPJ. APPJ-calcination improves the wettability of the CNTs printed on carbon cloth, as evidenced by water contact angle measurement. Raman spectroscopy indicates that reactive species of nitrogen APPJ react violently with CNTs in only 30-s APPJ processing time and introduce defects and/or surface functional groups on CNTs. Carbon cloths with calcined CNT layers are used as electrodes for liquid and quasi-solid-state electrolyte supercapacitors. Under a cyclic voltammetry test with a 2 mV/s potential scan rate, the specific capacitance is 73.84 F/g (areal capacitance = 5.89 mF/cm2) with a 2 M KCl electrolyte and 66.47 F/g (areal capacitance = 6.10 mF/cm2) with a H2SO4/polyvinyl alcohol (PVA) gel electrolyte.

  20. Multiphysics control of a two-fluid coaxial atomizer supported by electric-charge on the liquid jet

    Science.gov (United States)

    Machicoane, Nathanael; Osuna, Rodrigo; Aliseda, Alberto

    2017-11-01

    We present an experimental setup to investigate multiphysics control strategies on atomization of a laminar fluid stream by a coaxial turbulent jet. Spray control (i.e. driving the droplet size distribution and the spatio-temporal location of the droplets towards a desired objective) has many potential engineering applications, but requires a mechanistic understanding of the processes that control droplet formation and transport (primary and secondary instabilities, turbulent transport, hydrodynamic and electric forces on the droplets, ...). We characterize experimentally the break-up dynamics in a canonical coaxial atomizer, and the spray structure (droplet size, location, and velocity as a function of time) in a series of open loop conditions with harmonic forcing of the gas swirl ratio, liquid injection rate, the electric field strength at the nozzle and along the spray development region. The effect of these actuators are characterized for different gas Reynolds numbers ranging from 104-106. This open-loop characterization of the injector will be used to develop reduced order models for feedback control, as well as to validate assumptions underlying an adjoint-based computational control strategy. This work is part of a large-scale project funded by an ONR MURI to provide fundamental understanding of the mechanisms for feedback control of sprays.

  1. First application of liquid-metal-jet sources for small-animal imaging: high-resolution CT and phase-contrast tumor demarcation.

    Science.gov (United States)

    Larsson, Daniel H; Lundström, Ulf; Westermark, Ulrica K; Arsenian Henriksson, Marie; Burvall, Anna; Hertz, Hans M

    2013-02-01

    Small-animal studies require images with high spatial resolution and high contrast due to the small scale of the structures. X-ray imaging systems for small animals are often limited by the microfocus source. Here, the authors investigate the applicability of liquid-metal-jet x-ray sources for such high-resolution small-animal imaging, both in tomography based on absorption and in soft-tissue tumor imaging based on in-line phase contrast. The experimental arrangement consists of a liquid-metal-jet x-ray source, the small-animal object on a rotating stage, and an imaging detector. The source-to-object and object-to-detector distances are adjusted for the preferred contrast mechanism. Two different liquid-metal-jet sources are used, one circulating a Ga∕In∕Sn alloy and the other an In∕Ga alloy for higher penetration through thick tissue. Both sources are operated at 40-50 W electron-beam power with ∼7 μm x-ray spots, providing high spatial resolution in absorption imaging and high spatial coherence for the phase-contrast imaging. High-resolution absorption imaging is demonstrated on mice with CT, showing 50 μm bone details in the reconstructed slices. High-resolution phase-contrast soft-tissue imaging shows clear demarcation of mm-sized tumors at much lower dose than is required in absorption. This is the first application of liquid-metal-jet x-ray sources for whole-body small-animal x-ray imaging. In absorption, the method allows high-resolution tomographic skeletal imaging with potential for significantly shorter exposure times due to the power scalability of liquid-metal-jet sources. In phase contrast, the authors use a simple in-line arrangement to show distinct tumor demarcation of few-mm-sized tumors. This is, to their knowledge, the first small-animal tumor visualization with a laboratory phase-contrast system.

  2. Production and correlation of reactive oxygen and nitrogen species in gas- and liquid-phase generated by helium plasma jets under different pulse widths

    Science.gov (United States)

    Liu, Zhijie; Zhou, Chunxi; Liu, Dingxin; Xu, Dehui; Xia, Wenjie; Cui, Qingjie; Wang, Bingchuan; Kong, Michael G.

    2018-01-01

    In this paper, we present the effects of the pulse width (PW) on the plasma jet's discharge characteristics, particularly focusing on the production and correlation of the reactive oxygen and nitrogen species (RONS) in gas- and liquid-phase. It is found that the length of plasma jet plume first increases before the PW of 10 μs, then gradually decreases and finally almost remains unchanged beyond 150 μs. The plasma bullet disappears after the falling edge of the voltage pulse at low PW, while it terminates far ahead of the falling edge of voltage pulse at high PW. This is mainly attributed to accumulation of space charges that lead to weakening of the reduced electric field with an increase of PW from low to high. More important, it is found that the excited reactive species, the positive and negative ions from plasma jet, and the concentrations of NO2- and NO3- in deionized water exposed to plasma jet also display the first increasing and then decreasing change trend with increase of PW, while the concentration of H2O2 in water almost displays the linearly increasing trend. This mainly results from the formation of the H3O+ and HO2-, as well as their ion water clusters that can produce more OH radicals to be converted into H2O2, while the NO2- and NO3- in gas phase can transport into water and exist most stably in water. The water cluster formation at gas-liquid interface is an important key process that can affect the chemical nature and dose of aqueous RONS in water; this is beneficial for understanding how the RONS are formed in liquid-phase.

  3. Optimization of submerged vane parameters

    Indian Academy of Sciences (India)

    Submerged vanes are airfoils which are in general placed at certain angle with respect to the flow direction in a channel to induce artificial circulations downstream. By virtue of these artificially generated circulations, submerged vanes were utilized to protect banks of rivers against erosion, to control shifting of rivers, to avoid ...

  4. Optimization of submerged vane parameters

    Indian Academy of Sciences (India)

    H Sharma

    velocities simulated from CFD using standard k-x model were very much in accordance with what it was measured by Wang and Odgaard [4]. Thus, model can be used to study the turbulence characteristics around submerged vanes and to predict various parameters downstream of the submerged vanes. After the model ...

  5. Experimental investigation of effect of jet decay rate on jet-induced pressures on a flat plate

    Science.gov (United States)

    Kuhlman, J. M.; Ousterhout, D. S.; Warcup, R. W.

    1978-01-01

    An experimental study of the interaction between a lift jet and an aircraft wing for a jet VTOL aircraft was performed for the simplified model of an unheated, subsonic, circular jet exiting at right angles to a flat plate into a uniform subsonic crosswind. The effects of jet dynamic pressure decay rate upon the jet location and jet induced pressure distribution on the plate were studied over a range of jet to crossflow velocity ratios of 2.2 or = R or = 10. Jet decay rate was varied through use of cylindrical centerbodies with flat or hemispherical tips submerged in the jet nozzle at various depths below the jet exit plane. Quicker jet dynamic pressure decay, caused by the presence of a centerbody, resulted in reductions in the jet induced lift loss by as much as 45 percent relative to values for jets with no centerbody. These reductions in lift loss were observed at the larger values of crossflow velocity.

  6. Effects of irradiation distance on supply of reactive oxygen species to the bottom of a Petri dish filled with liquid by an atmospheric O{sub 2}/He plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Toshiyuki, E-mail: kawasaki@nbu.ac.jp; Kusumegi, Shota; Kudo, Akihiro; Sakanoshita, Tomohiro; Tsurumaru, Takuya; Sato, Akihiro [Department of Mechanical and Electrical Engineering, Nippon Bunri University, Oita, Oita 870-0397 (Japan); Uchida, Giichiro [Joining and Welding Research Institute, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Koga, Kazunori; Shiratani, Masaharu [Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Fukuoka 819-0395 (Japan)

    2016-05-07

    The impact of irradiation distances on plasma jet-induced specific effects on the supply of reactive oxygen species (ROS) to the bottom of a Petri dish filled with liquid was investigated using a KI-starch gel reagent that can be employed as a ROS indicator even in water. O{sub 3} exposure experiments without plasma irradiation were also performed to elucidate the specific effects of the plasma jet. Relative concentrations of ROS transported to the bottom were evaluated using absorbance measurements. The results indicated that ROS supply to the bottom is markedly enhanced by the plasma jet irradiation at shorter irradiation distances, whereas similar results could not be obtained for the O{sub 3} exposure. In these cases, the liquid mixing in the depth direction was also enhanced by the plasma jet irradiation only, and the supply of reactive atomic oxygen to the liquid surface was markedly increased as well.

  7. Flow pattern and cleaning performance of a stationary liquid jet operating at conditions relevant for industrial tank cleaning

    DEFF Research Database (Denmark)

    Feldung Damkjær, N.; Adler-Nissen, Jens; Jensen, B. B. B.

    2017-01-01

    jet was studied using a 19m3 tank and settings applicable to industrial operations; nozzle internal diameters, dN, of 2–5.5mm, cleaning distances, L, of 80–2490mm, and flow rates, Q, of 0.05–3.0m3h−1. Experimental data and model predictions of the behaviour of the jet when striking an unsoiled surface...... not accounted for in the mathematical models. The effects of jet break-up can partly be accommodated, in practice, by correcting the jet flow rate for these momentum losses....... showed reasonable agreement for a nozzle with dN=2mm at small cleaning distances (L 80 and 200mm). At greater dN and cleaning distances there was poorer agreement, which was attributed to jet break-up and splatter.Similar observations were made when cleaning a surface soiled with white petroleum jelly...

  8. Effects of jet decay rate on jet induced loads on a flat plate

    Science.gov (United States)

    Kuhlman, J. M.; Warcup, R. W.

    1977-01-01

    Experimental modelling of the interaction between a jet and an aircraft wing or fuselage in VTOL aircraft was undertaken using a cold jet exiting perpendicular to a flat plate in a uniform cross-flow. Effects of jet decay rate and jet-to-cross-flow velocity ratio, R, on the induced load distribution were investigated. Jet decay rate was increased by using cylindrical centerbodies submerged in the jet nozzle, which caused nonuniform initial jet velocity profiles. Quicker jet decay rate, corresponding to the presence of a centerbody, resulted in as much as 50% reduction in the induced pressure loads on the plate. This has implications in interpretation of results from earlier VTOL model studies of jet induced loads, where the jets have often had relatively slow decay rates due to uniform initial velocity profiles

  9. Submerged AUV Charging Station

    Science.gov (United States)

    Jones, Jack A.; Chao, Yi; Curtin, Thomas

    2014-01-01

    Autonomous Underwater Vehicles (AUVs) are becoming increasingly important for military surveillance and mine detection. Most AUVs are battery powered and have limited lifetimes of a few days to a few weeks. This greatly limits the distance that AUVs can travel underwater. Using a series of submerged AUV charging stations, AUVs could travel a limited distance to the next charging station, recharge its batteries, and continue to the next charging station, thus traveling great distances in a relatively short time, similar to the Old West “Pony Express.” One solution is to use temperature differences at various depths in the ocean to produce electricity, which is then stored in a submerged battery. It is preferred to have the upper buoy submerged a reasonable distance below the surface, so as not to be seen from above and not to be inadvertently destroyed by storms or ocean going vessels. In a previous invention, a phase change material (PCM) is melted (expanded) at warm temperatures, for example, 15 °C, and frozen (contracted) at cooler temperatures, for example, 8 °C. Tubes containing the PCM, which could be paraffin such as pentadecane, would be inserted into a container filled with hydraulic oil. When the PCM is melted (expanded), it pushes the oil out into a container that is pressurized to about 3,000 psi (approx equals 20.7 MPa). When a valve is opened, the high-pressure oil passes through a hydraulic motor, which turns a generator and charges a battery. The low-pressure oil is finally reabsorbed into the PCM canister when the PCM tubes are frozen (contracted). Some of the electricity produced could be used to control an external bladder or a motor to the tether line, such that depth cycling is continued for a very long period of time. Alternatively, after the electricity is generated by the hydraulic motor, the exiting low-pressure oil from the hydraulic motor could be vented directly to an external bladder on the AUV, such that filling of the bladder

  10. Production of Jet Fuels from Coal-Derived Liquids. Volume 12. Preliminary Process Design and Cost Estimate and Production Run Recommendation

    Science.gov (United States)

    1989-12-01

    Sulfolane Process licensed by Universal Oil Products. Referring to Drawings D5571-701A and B the flow is as follows: Stabilized Naphtha from the Naphtha...DTIC FILE COPY AD-A218 507 AFWAL-TR-87-2042 Volume XII PRODUCTION OF JET FUELS FROM COAL-DERIVED LIQUIDS VOL XII--PRELIMINARY PROCESS DESIGN AND COST...XII--Preliminary Process Design and Cost Estimate and Production Run Recommendation 12. PERSONAL AUTHOR(S) M. W. Furlong, J. D. Fox, J. G. Masin 13a

  11. Breakup of diminutive Rayleigh jets

    NARCIS (Netherlands)

    van Hoeve, W.; Gekle, S.; Snoeijer, Jacobus Hendrikus; Versluis, Michel; Brenner, Michael P.; Lohse, Detlef

    2010-01-01

    Discharging a liquid from a nozzle at sufficient large velocity leads to a continuous jet that due to capillary forces breaks up into droplets. Here we investigate the formation of microdroplets from the breakup of micron-sized jets with ultra high-speed imaging. The diminutive size of the jet

  12. Control of reactive oxygen and nitrogen species production in liquid by nonthermal plasma jet with controlled surrounding gas

    Science.gov (United States)

    Ito, Taiki; Uchida, Giichiro; Nakajima, Atsushi; Takenaka, Kosuke; Setsuhara, Yuichi

    2017-01-01

    We present the development of a low-frequency nonthermal plasma-jet system, where the surrounding-gas condition of the plasma jet is precisely controlled in open air. By restricting the mixing of the ambient air into the plasma jet, the plasma jet can be selectively changed from a N2 main discharge to an O2 main discharge even in open air. In the plasma-jet system with the controlled surrounding gas, the production of reactive oxygen and nitrogen species is successfully controlled in deionized water: the concentration ratio of NO2 - to H2O2 is tuned from 0 to 0.18, and a high NO2 - concentration ratio is obtained at a N2 gas ratio of 0.80 relative to the total N2/O2 gas mixture in the main discharge gas. We also find that the NO2 - concentration is much higher in the plasma-activated medium than in the plasma-activated deionized water, which is mainly explained by the contribution of amino acids to NO2 - generation in the medium.

  13. SUBMERGED PERFUSION BIOREACTOR

    DEFF Research Database (Denmark)

    2010-01-01

    NOVELTY - A biological device comprises a body (1) delimited by a rim (7) comprising recessed portion(s) that is a cavity in the rim of the body, and a first wall delimiting the recessed portion along the cavity. The recessed portion(s) comprise a first outlet orifice allowing the liquid medium t...

  14. Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

    Science.gov (United States)

    Jablonowski, H.; Bussiahn, R.; Hammer, M. U.; Weltmann, K.-D.; von Woedtke, Th.; Reuter, S.

    2015-12-01

    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100-400 nm) and, in particular, vacuum ultraviolet (VUV, 10-200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH2O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H2O2) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O2•-) and hydroxyl radicals (•OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

  15. Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

    Energy Technology Data Exchange (ETDEWEB)

    Jablonowski, H.; Hammer, M. U.; Reuter, S. [Center for Innovation Competence plasmatis, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Bussiahn, R.; Weltmann, K.-D.; Woedtke, Th. von [Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2015-12-15

    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100–400 nm) and, in particular, vacuum ultraviolet (VUV, 10–200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH{sub 2}O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H{sub 2}O{sub 2}) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O{sub 2}{sup •−}) and hydroxyl radicals ({sup •}OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

  16. Mounding of a non-Newtonian jet impinging on a solid substrate.

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, Peter Randall; Grillet, Anne Mary; Roberts, Scott A.; Baer, Thomas A. (Procter & Gamble, Cincinnati, OH); Rao, Rekha Ranjana

    2010-06-01

    When a fluid jet impinges on a solid substrate, a variety of behaviors may occur around the impact region. One example is mounding, where the fluid enters the impact region faster than it can flow away, forming a mound of fluid above the main surface. For some operating conditions, this mound can destabilize and buckle, entraining air in the mound. Other behaviors include submerging flow, where the jet impinges into an otherwise steady pool of liquid, entraining a thin air layer as it enters the pool. This impact region is one of very high shear rates and as such, complex fluids behave very differently than do Newtonian fluids. In this work, we attempt to characterize this range of behavior for Newtonian and non-Newtonian fluids using dimensionless parameters. We model the fluid as a modified Bingham-Carreau-Yasuda fluid, which exhibits the full range of pseudoplastic flow properties throughout the impact region. Additionally, we study viscoelastic effects through the use of the Giesekus model. Both 2-D and 3-D numerical simulations are performed using a variety of finite element method techniques for tracking the jet interface, including Arbitrary Lagrangian Eulerian (ALE), diffuse level sets, and a conformal decomposition finite element method (CDFEM). The presence of shear-thinning characteristics drastically reduces unstable mounding behavior, yet can lead to air entrainment through the submerging flow regime. We construct an operating map to understand for what flow parameters mounding and submerging flows will occur, and how the fluid rheology affects these behaviors. This study has many implications in high-speed industrial bottle filling applications.

  17. Drought and submergence tolerance in plants

    Science.gov (United States)

    Du, Hewei; Zhou, Yufan; Oksenberg, Nir; Ronald, Pamela

    2017-11-14

    The invention provides methods of genetically modified plants to increase tolerance to drought and/or submergence. The invention additionally provides plants having increased drought and/or submergence tolerance engineered using such methods.

  18. Twin Jet

    Science.gov (United States)

    Henderson, Brenda; Bozak, Rick

    2010-01-01

    Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in close proximity. Engine configurations with multiple jets have the ability to exploit jet-by-jet shielding which may significantly reduce noise. Jet-by-jet shielding is the ability of one jet to shield noise that is emitted by another jet. The sensitivity of jet-by-jet shielding to jet spacing and simulated flight stream Mach number are not well understood. The current experiment investigates the impact of jet spacing, jet operating condition, and flight stream Mach number on the noise radiated from subsonic and supersonic twin jets.

  19. Submerged membrane distillation for desalination of water

    KAUST Repository

    Francis, Lijo

    2016-10-27

    Submerged membrane modules for use for desalination of water are disclosed. In one or more aspects, the membrane modules can be submerged either in a feed solution tank or the feed solution can pass through the lumen side of the membrane submerged within the tank. The feed solution can be a water-based feed stream containing an amount of salt.

  20. Production of Jet Fuels from Coal-Derived Liquids. Volume 2. Characterization of Liquid By-Products from the Great Plains Gasification Plant

    Science.gov (United States)

    1988-05-01

    against acetanilide , although other appropriate standards could be used. Equipment calibrated for the elemental analysis of coal liquids provides high...distributions of the THF solubles of non- distillables were determined by gel permeation chromatography (GPC). GPC analysis showed a larger amount of lower

  1. On the submerging of a spherical intruder into granular beds

    Science.gov (United States)

    Wu, Chuan-Yu; Zhang, Ling; Chen, Lan

    2017-06-01

    Granular materials are complex systems and their mechanical behaviours are determined by the material properties of individual particles, the interaction between particles and the surrounding media, which are still incompletely understood. Using an advanced discrete element method (DEM), we simulate the submerging process of a spherical projectile (an intruder) into granular materials of various properties with a zero penetration velocity (i.e. the intruder is touching the top surface of the granular bed and released from stationary) and examine its settling behaviour. By systematically changing the density and size of the intruder and the particle density (i.e. the density of the particles in the granular bed), we find that the intruder can sink deep into the granular bed even with a zero penetration velocity. Furthermore, we confirm that under certain conditions the granular bed can behave like a Newtonian liquid and the submerging intruder can reach a constant velocity, i.e. the terminal velocity, identical to the settling of a sphere in a liquid, as observed experimentally. A mathematical model is also developed to predict the maximum penetration depth of the intruder. The model predictions are compared with experimental data reported in the literature,good agreement was obtained, demonstrating the model can accurately predict the submerging behaviour of the intruder in the granular media.

  2. On the submerging of a spherical intruder into granular beds

    Directory of Open Access Journals (Sweden)

    Wu Chuan-Yu

    2017-01-01

    Full Text Available Granular materials are complex systems and their mechanical behaviours are determined by the material properties of individual particles, the interaction between particles and the surrounding media, which are still incompletely understood. Using an advanced discrete element method (DEM, we simulate the submerging process of a spherical projectile (an intruder into granular materials of various properties with a zero penetration velocity (i.e. the intruder is touching the top surface of the granular bed and released from stationary and examine its settling behaviour. By systematically changing the density and size of the intruder and the particle density (i.e. the density of the particles in the granular bed, we find that the intruder can sink deep into the granular bed even with a zero penetration velocity. Furthermore, we confirm that under certain conditions the granular bed can behave like a Newtonian liquid and the submerging intruder can reach a constant velocity, i.e. the terminal velocity, identical to the settling of a sphere in a liquid, as observed experimentally. A mathematical model is also developed to predict the maximum penetration depth of the intruder. The model predictions are compared with experimental data reported in the literature,good agreement was obtained, demonstrating the model can accurately predict the submerging behaviour of the intruder in the granular media.

  3. Experimental investigation of jet-induced loads on a flat plate in hover out-of-ground effect

    Science.gov (United States)

    Kuhlman, J. M.; Warcup, R. W.

    1979-01-01

    Effects of varying jet decay rate on jet-induced loads on a flat plate located in the plane of the jet exit perpendicular to the jet axis were investigated using a small-scale laboratory facility. Jet decay rate has been varied through use of two cylindrical centerbodies having either a flat or hemispherical tip, which were submerged various distances below the flat plate jet exit plane. Increased jet decay rate, caused by the presence of a center-body or plug in the jet nozzle, led to an increased jet-induced lift loss on the flat plate. Jet-induced lift losses reached 1 percent of the jet thrust for the quickest jet decay rates for plate areas equal to 100 times the effective jet exit area. The observed lift loss versus jet decay rate trend agreed well with results of previous investigations.

  4. Determining the Discharge Rate from a Submerged Oil Leaks using ROV Video and CFD study

    Science.gov (United States)

    Saha, Pankaj; Shaffer, Frank; Shahnam, Mehrdad; Savas, Omer; Devites, Dave; Steffeck, Timothy

    2016-11-01

    The current paper reports a technique to measure the discharge rate by analyzing the video from a Remotely Operated Vehicle (ROV). The technique uses instantaneous images from ROV video to measure the velocity of visible features (turbulent eddies) along the boundary of an oil leak jet and subsequently classical theory of turbulent jets is imposed to determine the discharge rate. The Flow Rate Technical Group (FRTG) Plume Team developed this technique that manually tracked the visible features and produced the first accurate government estimates of the oil discharge rate from the Deepwater Horizon (DWH). For practical application this approach needs automated control. Experiments were conducted at UC Berkeley and OHMSETT that recorded high speed, high resolution video of submerged dye-colored water or oil jets and subsequently, measured the velocity data employing LDA and PIV software. Numerical simulation have been carried out using experimental submerged turbulent oil jets flow conditions employing LES turbulence closure and VOF interface capturing technique in OpenFOAM solver. The CFD results captured jet spreading angle and jet structures in close agreement with the experimental observations. The work was funded by NETL and DOI Bureau of Safety and Environmental Enforcement (BSEE).

  5. Investigation of submerged waterjet cavitation through surface property and flow information in ambient water

    Science.gov (United States)

    Kang, Can; Liu, Haixia; Zhang, Tao; Li, Qing

    2017-12-01

    To illuminate primary factors influencing the morphology of the surface impinged by submerged waterjet, experiments were performed at high jet pressures from 200 to 320 MPa. The cavitation phenomenon involved in the submerged waterjet was emphasized. Copper specimens were used as the targets enduring the impingement of high-pressure waterjets. The microhardness of the specimen was measured. Surface morphology was observed using an optical profiling microscope. Pressure fluctuations near the jet stream were acquired with miniature pressure transducers. The results show that microhardness increases with jet pressure and impingement time, and the hardening effect is restricted within a thin layer underneath the target surface. A synthetic effect is testified with the plastic deformation and cavities on the specimen surfaces. Characteristics of different cavitation erosion stages are illustrated by surface morphology. At the same jet pressure, the smallest standoff distance is not corresponding to the highest mass removal rate. Instead, there is an optimal standoff distance. With the increase of jet pressure, overall mass removal rate rises as well. Low-frequency components are predominant in the pressure spectra and the dual-peak pattern is typical. As the streamwise distance from the nozzle is enlarged, pressure amplitudes associated with cavitation bubble collapse are improved.

  6. Gas dynamics of a supersonic radial jet. Part I

    Science.gov (United States)

    Kosarev, V. F.; Klinkov, S. V.; Zaikovskii, V. N.; Kundasev, S. G.

    2015-11-01

    The gas dynamics of a supersonic radial jet was studied under conditions close to cold spraying. The jet visualization was performed for exhaustion into submerged space with atmospheric pressure and jet impingement to a target. For the cases of swirled and unswirled supersonic radial jets, the pressure profiles measured by a Pitot tube were taken for different distances from the nozzle outlet and for different widths of supersonic part δ ex = 0.5-2 mm and for prechamber pressure in the range p 0 = 1-2.5 MPa.

  7. Flow and scour around vertical submerged structures

    Indian Academy of Sciences (India)

    Although past investigations establish the effect of various parameters on scour around vertical submerged structures for live and clear water condition, yet further studies are required to analyze the scour around group of submerged structures for various bed sediments, understand the flow physics around the group and ...

  8. Green-House-Gas-Reduced Coal-and-Biomass-to-Liquid-Based Jet Fuel (GHGR-CBTL) Process - Final Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Lux, Kenneth [Altex Technologies Corporation, Sunnyvale, CA (United States); Imam, Thamina [Altex Technologies Corporation, Sunnyvale, CA (United States); Chevanan, Nehru [Altex Technologies Corporation, Sunnyvale, CA (United States); Namazian, Mehdi [Altex Technologies Corporation, Sunnyvale, CA (United States); Wang, Xiaoxing [Pennsylvania State Univ., University Park, PA (United States); Song, Chunshan [Pennsylvania State Univ., University Park, PA (United States)

    2017-11-03

    This Final Technical Report describes the work and accomplishments of the project entitled, “Green-House-Gas-Reduced Coal-and-Biomass-to-Liquid-Based Jet Fuel (GHGR-CBTL) Process”. The main objective of the project was to raise the Technology Readiness Level (TRL) of the GHGR-CBTL fuel-production technology from TRL 4 to TRL 5 by producing a drop-in synthetic Jet Propellant 8 (JP-8) with a greenhouse-gas footprint less than or equal to petroleum-based JP-8 by utilizing mixtures of coal and biomass as the feedstock. The system utilizes the patented Altex fuel-production technology, which incorporates advanced catalysts developed by Pennsylvania State University. While the system was not fabricated and tested, major efforts were expended to design the 1-TPD and a full-scale plant. The system was designed, a Block-Flow Diagram (BFD), a Process-Flow Diagram (PFD), and Piping-and-Instrumentation Diagrams (P&IDs) were produced, a Bill of Materials (BOM) and associated spec sheets were produced, commercially available components were selected and procured, custom components were designed and fabricated, catalysts were developed and screened for performance, and permitting activities were conducted. Optimization tests for JP-8 production using C2 olefin as the feed were performed over a range of temperatures, pressures and WHSVs. Liquid yields of between 63 to 65% with 65% JP-8 fraction (41-42% JP-8 yield) at 50 psig were achieved. Life-Cycle Analysis (LCA) was performed by Argonne National Laboratory (ANL), and a GHGR-CBTL module was added to the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET®) model. Based upon the experimental results, the plant design was reconfigured for zero natural-gas imports and minimal electricity imports. The LCA analysis of the reconfigured process utilizing the GREET model showed that if the char from the process was utilized to produce combined heat and power (CHP) then a feed containing 23 wt% biomass and

  9. Heat transfer model for quenching by submerging

    Energy Technology Data Exchange (ETDEWEB)

    Passarella, D N; Varas, F [Departamento de Matematica Aplicada II, E.T.S. de Ing. de Telecomunicacion, Universidad de Vigo, Campus Marcosende, 36310 Vigo (Spain); MartIn, E B, E-mail: diego@dma.uvigo.es, E-mail: fvaras@uvigo.es, E-mail: emortega@uvigo.es [Area de Mecanica de Fluidos, E.T.S. de Ing. Industriales, Universidad de Vigo, Campus Marcosende, 36310 Vigo (Spain)

    2011-05-01

    In quenching by submerging the workpiece is cooled due to vaporization, convective flow and interaction of both mechanisms. The dynamics of these phenomena is very complex and the corresponding heat fluxes are strongly dependent on local flow variables such as velocity of fluid and vapor fraction. This local dependence may produce very different cooling rates along the piece, responsible for inappropriate metallurgical transformations, variability of material properties and residual stresses. In order to obtain an accurate description of cooling during quenching, a mathematical model of heat transfer is presented here. The model is based on the drift-flux mixture-model for multiphase flows, including an equation of conservation of energy for the liquid phase and specific boundary conditions that account for evaporation and presence of vapor phase on the surface of the piece. The model was implemented on Comsol Multiphysics software. Generation of appropriate initial and boundary conditions, as well as numerical resolution details, is briefly discussed. To test the model, a simple flow condition was analyzed. The effect of vapor fraction on heat transfer is assessed. The presence of the typical vapor blanket and its collapse can be recovered by the model, and its effect on the cooling rates on different parts of the piece is analyzed. Comparisons between numerical results and data from literature are made.

  10. Fuzzy jets

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, Lester [Department of Statistics, Stanford University,Stanford, CA 94305 (United States); Nachman, Benjamin [Department of Physics, Stanford University,Stanford, CA 94305 (United States); SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Schwartzman, Ariel [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Stansbury, Conrad [Department of Physics, Stanford University,Stanford, CA 94305 (United States)

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets. To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets, are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

  11. Liquid Oxygen Thermodynamic Vent System Testing with Helium Pressurization

    Science.gov (United States)

    VanDresar, Neil T.

    2014-01-01

    This report presents the results of several thermodynamic vent system (TVS) tests with liquid oxygen plus a test with liquid nitrogen. In all tests, the liquid was heated above its normal boiling point to 111 K for oxygen and 100 K for nitrogen. The elevated temperature was representative of tank conditions for a candidate lunar lander ascent stage. An initial test series was conducted with saturated oxygen liquid and vapor at 0.6 MPa. The initial series was followed by tests where the test tank was pressurized with gaseous helium to 1.4 to 1.6 MPa. For these tests, the helium mole fraction in the ullage was quite high, about 0.57 to 0.62. TVS behavior is different when helium is present than when helium is absent. The tank pressure becomes the sum of the vapor pressure and the partial pressure of helium. Therefore, tank pressure depends not only on temperature, as is the case for a pure liquid-vapor system, but also on helium density (i.e., the mass of helium divided by the ullage volume). Thus, properly controlling TVS operation is more challenging with helium pressurization than without helium pressurization. When helium was present, the liquid temperature would rise with each successive TVS cycle if tank pressure was kept within a constant control band. Alternatively, if the liquid temperature was maintained within a constant TVS control band, the tank pressure would drop with each TVS cycle. The final test series, which was conducted with liquid nitrogen pressurized with helium, demonstrated simultaneous pressure and temperature control during TVS operation. The simultaneous control was achieved by systematic injection of additional helium during each TVS cycle. Adding helium maintained the helium partial pressure as the liquid volume decreased because of TVS operation. The TVS demonstrations with liquid oxygen pressurized with helium were conducted with three different fluid-mixer configurations-a submerged axial jet mixer, a pair of spray hoops in the tank

  12. Active Control Strategies to Optimize Supersonic Fuel-Air Mixing for Combustion Associated with Fully Modulated Transverse Jet in Cross Flow

    National Research Council Canada - National Science Library

    Ghenai, C; Philippidis, G. P; Lin, C. X

    2005-01-01

    ... (subsonic- supersonic) combustion studies. A high-speed imaging system was used for the visualization of pure liquid jet, aerated liquid jet and pulsed aerated jet injection into a supersonic cross flow at Mach number 1.5...

  13. Effects of electromagnetic forcing on self-sustained jet oscillations

    NARCIS (Netherlands)

    Kalter, R.; Tummers, M.J.; Kenjeres, S.; Righolt, B.W.; Kleijn, C.R.

    2014-01-01

    The influence of electromagnetic forcing on self-sustained oscillations of a jet issuing from a submerged nozzle into a thin vertical cavity (width W much larger than thickness T) has been studied using particle image velocimetry. A permanent Lorentz force is produced by applying an electrical

  14. Untwisting Jets Related to Magnetic Flux Cancellation

    Science.gov (United States)

    Liu, Jiajia; Erdélyi, Robert; Wang, Yuming; Liu, Rui

    2018-01-01

    The rotational motion of solar jets is believed to be a signature of the untwisting process resulting from magnetic reconnection, which takes place between twisted closed magnetic loops (i.e., magnetic flux ropes) and open magnetic field lines. The identification of the pre-existing flux rope, and the relationship between the twist contained in the rope and the number of turns the jet experiences, are then vital in understanding the jet-triggering mechanism. In this paper, we will perform a detailed analysis of imaging, spectral, and magnetic field observations of four homologous jets, among which the fourth one releases a twist angle of 2.6π. Nonlinear force-free field extrapolation of the photospheric vector magnetic field before the jet eruption presents a magnetic configuration with a null point between twisted and open fields—a configuration highly in favor of the eruption of solar jets. The fact that the jet rotates in the opposite sense of handness to the twist contained in the pre-eruption photospheric magnetic field confirms the unwinding of the twist by the jet’s rotational motion. The temporal relationship between jets’ occurrence and the total negative flux at their source region, together with the enhanced magnetic submergence term of the photospheric Poynting flux, shows that these jets are highly associated with local magnetic flux cancellation.

  15. Tissue dissection before direct manipulation to the pathology with pulsed laser-induced liquid jet system in skull base surgery--preservation of fine vessels and maintained optic nerve function.

    Science.gov (United States)

    Ogawa, Yoshikazu; Nakagawa, Atsuhiro; Washio, Toshikatsu; Arafune, Tatsuhiko; Tominaga, Teiji

    2013-10-01

    Most difficulties in skull base tumor removal are generally caused by adhesion of feeding arteries to the vital structures and cranial nerves. Water jet technology provides tissue dissectability with preservation of fine blood vessels both in experimental and clinical situations. However problems still remain regarding whether tumor removal with preservation of peripheral nerve function is possible or not. This clinical investigation evaluated functional preservation of peripheral nerves and dissectability with a newly developed pulsed laser-induced liquid jet (LILJ) system under intraoperative electrophysiological monitoring. The LILJ system was used to treat 21 patients with skull base tumors manifesting as severe visual disturbance through the extended transsphenoidal approach. The LILJ system consists of a bayonet-shaped catheter incorporating a jet generator, and total weight is around 7 g. Intraoperative visual evoked potential (VEP), and pre/postoperative conventional visual assessments were investigated. Precise dissections of the tumor were obtained, resulting in gross total removal in 19 of 21 patients. Two patients with meningiomas with tight adhesion to the origin of the lenticulostriate arteries had small remnants. Of the 21 patients, 16 showed immediate improvement on intraoperative VEP, 2 had no change, and 3 had prolonged latency, which required intermittent suspension of procedure. A total of 20 patients and 40 eyes showed good recovery at discharge, and all patients evaluated had recovered good visual status. The LILJ system can achieve safe and optimal removal with functional preservation of optic nerves, probably because of the high resistance of the arachnoidal sheath and fine vascular tissue.

  16. Jet impact on a soap film.

    Science.gov (United States)

    Kirstetter, Geoffroy; Raufaste, Christophe; Celestini, Franck

    2012-09-01

    We experimentally investigate the impact of a liquid jet on a soap film. We observe that the jet never breaks the film and that two qualitatively different steady regimes may occur. The first one is a refractionlike behavior obtained at small incidence angles when the jet crosses the film and is deflected by the film-jet interaction. For larger incidence angles, the jet is absorbed by the film, giving rise to a new class of flows in which the jet undulates along the film with a characteristic wavelength. Besides its fundamental interest, this paper presents a different way to guide a micrometric flow of liquid in the inertial regime and to probe foam stability submitted to violent perturbations at the soap film scale.

  17. Impeller Submergence Depth for Stirred Tanks

    Directory of Open Access Journals (Sweden)

    Thiyam T. Devi

    2011-11-01

    Full Text Available Impeller submergence governs the performance of mixing tanks employed in oxygen transfer operation. Present work experimentally investigates the effect of impeller submergence depths on oxygen transfer and corresponding power consumption. It has been found that at higher range of impeller submergence, mixing tanks consume less power and gives higher values of oxygen transfer coefficient. Optimal range of submergence depth is 0.7 to 0.9 times the impeller diameter. Copyright ©2011 BCREC UNDIP. All rights reserved.(Received: 4th March 2011; Revised: 12nd July 2011; Accepted: 14th July 2011[How to Cite: T.T. Devi, A.P. Sinha, M. Thakre, and B. Kumar. (2011. Impeller Submergence Depth for Stirred Tanks. Bulletin of Chemical Reaction Engineering & Catalysis, 6 (2: 123-128. doi:10.9767/bcrec.6.2.826.123-128][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.2.826.123-128 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/826] | View in 

  18. Fabrication of micro/nano-structures by electrohydrodynamic jet technique

    Science.gov (United States)

    Wang, Dazhi; Zhao, Xiaojun; Lin, Yigao; Ren, Tongqun; Liang, Junsheng; Liu, Chong; Wang, Liding

    2017-12-01

    Electrohydrodynamic jet (E-Jet) is an approach to the fabrication of micro/nano-structures by the use of electrical forces. In this process, the liquid is subjected to electrical and mechanical forces to form a liquid jet, which is further disintegrated into droplets. The major advantage of the E-Jet technique is that the sizes of the jet formed can be at the nanoscale far smaller than the nozzle size, which can realize high printing resolution with less risk of nozzle blockage. The E-Jet technique, which mainly includes E-Jet deposition and E-Jet printing, has a wide range of applications in the fabrication of micro/nano-structures for micro/nano-electromechanical system devices. This technique is also considered a micro/nano-fabrication method with a great potential for commercial use. This study mainly reviews the E-Jet deposition/printing fundamentals, fabrication process, and applications.

  19. Laser Beam Submerged Arc Hybrid Welding

    Science.gov (United States)

    Reisgen, Uwe; Olschok, Simon; Jakobs, Stefan; Schleser, Markus; Mokrov, Oleg; Rossiter, Eduardo

    The laser beam-submerged arc hybrid welding method originates from the knowledge that, with increasing penetration depth, the laser beam process has a tendency to pore formation in the lower weld regions. The coupling with the energy-efficient submerged-arc process improves degassing and reduces the tendency to pore formation. The high deposition rate of the SA process in combination with the laser beam process offers, providing the appropriate choice of weld preparation, the possibility of welding plates with a thickness larger than 20° mm in a single pass, and also of welding thicker plates with the double-sided single pass technique.

  20. Multielement stoichiometry of submerged macrophytes across Yunnan plateau lakes (China)

    National Research Council Canada - National Science Library

    Xing, Wei; Wu, Haoping; Shi, Qiao; Hao, Beibei; Liu, Han; Wang, Zhixiu; Liu, Guihua

    2015-01-01

    .... We predicted that tissue element composition in submerged macrophytes is affected by lake trophic level and taxonomy, and submerged macrophytes have weak stoichiometric homeostasis for all above 16 elements...

  1. Emerging Jets

    CERN Document Server

    Schwaller, Pedro; Weiler, Andreas

    2015-01-01

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilit...

  2. Take-Off and Flight Performance of an A-20A Airplane as Affected by Auxiliary Propulsion Supplied by Liquid Propellant Jet Units

    Science.gov (United States)

    1942-06-30

    investigating a number of »paclal problema that arose fron the specif lention» set up by tba Amy Air forces Materiel Center for a Jet unit suitable for...Regarding Setalla of Vila Analyaie and Calculation«. General 7-JL Take-Off Point 8-A Elevations 10-* Calculation« 10-* Film Analyaie >oric Sheet

  3. Oxygen dynamics in submerged rice (Oryza sativa L.)

    DEFF Research Database (Denmark)

    Colmer, Timothy D.; Pedersen, Ole

    2008-01-01

    Complete submergence of plants prevents direct O2 and CO2 exchange with air. Underwater photosynthesis can result in marked diurnal changes in O2 supply to submerged plants. Dynamics in pO2 had not been measured directly for submerged rice (Oryza sativa), but in an earlier study, radial O2 loss...

  4. Benthic bacterial diversity in submerged sinkhole ecosystems.

    Science.gov (United States)

    Nold, Stephen C; Pangborn, Joseph B; Zajack, Heidi A; Kendall, Scott T; Rediske, Richard R; Biddanda, Bopaiah A

    2010-01-01

    Physicochemical characterization, automated ribosomal intergenic spacer analysis (ARISA) community profiling, and 16S rRNA gene sequencing approaches were used to study bacterial communities inhabiting submerged Lake Huron sinkholes inundated with hypoxic, sulfate-rich groundwater. Photosynthetic cyanobacterial mats on the sediment surface were dominated by Phormidium autumnale, while deeper, organically rich sediments contained diverse and active bacterial communities.

  5. Production of extracellular aspartic protease in submerged ...

    African Journals Online (AJOL)

    Yomi

    29(1): 1-6. Fraile ER, Bernardinelli SE, Handel M, Jauregui AM (1978). Selección de cepas de Mucor sp productoras de enzimas coagulantes de leche. Rev. Arg. Microbiol. 10(2): 65-69. Ghareib M, Hamdy HS, Khalil AA (2001). Production of intracellular milk clotting enzyme in submerged cultures of Fusarium subglutinans.

  6. Topology optimization for submerged buoyant structures

    NARCIS (Netherlands)

    Picelli, R.; van Dijk, R.; Vicente, W.M.; Pavanello, R.; Langelaar, M.; van Keulen, A.

    2017-01-01

    This paper presents an evolutionary structural topology optimization method for the design of completely submerged buoyant modules with design-dependent fluid pressure loading. This type of structure is used to support offshore rig installation and pipeline transportation at all water depths. The

  7. Production of extracellular aspartic protease in submerged ...

    African Journals Online (AJOL)

    Fungal milk-clotting enzymes have gained value as bovine Chymosin substitutes in the cheese industry. In this work, the effects of culture conditions on the production of extracellular milk clotting enzymes from Mucor mucedo DSM 809 in submerged fermentation were studied. The maximum activity was observed after 48 h ...

  8. Life-Cycle Energy Use and Greenhouse Gas Emissions Analysis for Bio-Liquid Jet Fuel from Open Pond-Based Micro-Algae under China Conditions

    OpenAIRE

    Xiliang Zhang; Xu Zhang; Xunmin Ou; Xiaoyu Yan

    2013-01-01

    A life-cycle analysis (LCA) of greenhouse gas (GHG) emissions and energy use was performed to study bio-jet fuel (BJF) production from micro-algae grown in open ponds under Chinese conditions using the Tsinghua University LCA Model (TLCAM). Attention was paid to energy recovery through biogas production and cogeneration of heat and power (CHP) from the residual biomass after oil extraction, including fugitive methane (CH 4 ) emissions during the production of biogas and nitrous oxide (N 2 O) ...

  9. Growth rate measurement in free jet experiments

    Science.gov (United States)

    Charpentier, Jean-Baptiste; Renoult, Marie-Charlotte; Crumeyrolle, Olivier; Mutabazi, Innocent

    2017-07-01

    An experimental method was developed to measure the growth rate of the capillary instability for free liquid jets. The method uses a standard shadow-graph imaging technique to visualize a jet, produced by extruding a liquid through a circular orifice, and a statistical analysis of the entire jet. The analysis relies on the computation of the standard deviation of a set of jet profiles, obtained in the same experimental conditions. The principle and robustness of the method are illustrated with a set of emulated jet profiles. The method is also applied to free falling jet experiments conducted for various Weber numbers and two low-viscosity solutions: a Newtonian and a viscoelastic one. Growth rate measurements are found in good agreement with linear stability theory in the Rayleigh's regime, as expected from previous studies. In addition, the standard deviation curve is used to obtain an indirect measurement of the initial perturbation amplitude and to identify beads on a string structure on the jet. This last result serves to demonstrate the capability of the present technique to explore in the future the dynamics of viscoelastic liquid jets.

  10. A novel needleless liquid jet injection methodology for improving direct cardiac gene delivery: An optimization of parameters, AAV mediated therapy and investigation of host responses in ischemic heart failure

    Science.gov (United States)

    Fargnoli, Anthony Samuel

    Heart disease remains the leading cause of mortality and morbidity worldwide, with 22 million new patients diagnosed annually. Essentially, all present therapies have significant cost burden to the healthcare system, yet fail to increase survival rates. One key employed strategy is the genetic reprogramming of cells to increase contractility via gene therapy, which has advanced to Phase IIb Clinical Trials for advanced heart failure patients. It has been argued that the most significant barrier preventing FDA approval are resolving problems with safe, efficient myocardial delivery, whereby direct injection in the infarct and remote tissue areas is not clinically feasible. Here, we aim to: (1) Improve direct cardiac gene delivery through the development of a novel liquid jet device approach (2) Compare the new method against traditional IM injection with two different vector constructions and evaluate outcome (3) Evaluate the host response resulting from both modes of direct cardiac injection, then advance a drug/gene combination with controlled release nanoparticle formulations.

  11. The effect of the gap distance between an atmospheric-pressure plasma jet nozzle and liquid surface on OH and N2 species concentrations

    Science.gov (United States)

    Ghimire, Bhagirath; Sornsakdanuphap, Jirapong; Hong, Young June; Uhm, Han Sup; Weltmann, Klaus-Dieter; Choi, Eun Ha

    2017-07-01

    An argon plasma jet at atmospheric pressure was operated at various gap distances between the nozzle of the plasma jet and the water surface in order to study the formation of OH and N2 species in the vicinity of the water surface. Plasma was generated using a 24 kHz sinusoidal power supply at a steady gas flow-rate of 200 sccm. The electron temperature and rotational temperature of gas species were measured using optical emission spectroscopy and found to decrease with increasing gap distance. Meanwhile, the electron density calculated from jet current measurement increased with increasing gap distance. The average OH concentration reduced from 6.10 × 1015 cm-3 to 1.35 × 1015 cm-3, as the gap distance increased from 1 to 4 mm. The 337 nm N2 second positive system studied by optical emission spectroscopy and temporal emission signals increased with increasing gap distance. Plasma activated water was also made from various gap distances in order to confirm the presence of particular reactive oxygen or nitrogen species inside the water. The maximum observed absorbance corresponding to nitrogen oxide was in the spectral range of 230-250 nm from the 4 mm gap distance, while another maximum was recorded in the range of 250-260 nm corresponding to H2O2 from the 1 mm gap distance. Our experimental observations indicate that reactive oxygen and nitrogen species may be generated above the water surface or penetrate into some biological fluids, suggesting that their particular production can be tailored by the variation of the gap distance.

  12. Pump Coastdown with the Submerged Flywheel

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hyun-Gi; Seo, KyoungWoo; Kim, Seong Hoon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Many research reactors are generally designed as open pool types in consideration of the heat removal of the nuclear fuels, reactor operation and accessibility. Reactor structure assembly is generally placed at the pool bottom as shown in Fig. 1. Primary cooling system pump circulates the coolant from the reactor structure to the heat exchanger in order to continuously remove the heat generated from the reactor core in the research reactor as shown in Fig. 1. The secondary cooling system releases the transferred heat to the atmosphere by the cooling tower. Coastdown flow rate of the primary cooling system pump with the submerged flywheel are calculated analytically in case of the accident situation. Coastdown flow rate is maintained until almost 80 sec when the pump stops normally. But, coastdown flow rate is rapidly decreased when the flywheel is submerged because of the friction load on the flywheel surface.

  13. Pileup Jet Identification

    CERN Document Server

    CMS Collaboration

    2013-01-01

    High pileup in LHC collisions can increase incidence of jets by several large factors. To reduce the incidence of jets from pileup and to preserve the rate of good jets, a jet identification based on both vertex information and jet shape information has been developed. The construction of this jet identifier is described and the performances are evaluated using both Z+jets MC simulated samples and Z+jets data collected in the 2012 $\\sqrt{s}=8$ TeV run. The effectiveness of this jet identifier is discussed in the context of jet vetoes and vector boson fusion production.

  14. Coastline Protection by a Submerged Breakwater

    Science.gov (United States)

    Valentine, B. D.; Hayatdavoodi, M.; Ertekin, R. C.

    2016-02-01

    Coastal communities are in danger of the impact caused by storm surge and waves. Storm surge brings the water level to a higher elevation and farther inland. This rise in water level increases the chance of a higher number and larger set of waves approaching shorelines, and it can potentially devastate the coastal infrastructure. In this study, we evaluate the performance of a submerged, horizontal breakwater located near shore. Unlike other types of breakwaters, such as the ones that extend to the surface, either fixed or floating, a submerged horizontal breakwater does not create any visual distraction or limit most of the recreational and commercial activities in the nearshore areas. The Level I Green-Naghdi (GN) nonlinear water wave equations are utilized here to study the wave transformation over a submerged breakwater that is located in shallow water. The GN theory is based on the theory of directed fluid sheets and assumes an incompressible and inviscid fluid; no assumption on the rotationality of the flow is required. In this approach, the nonlinear boundary conditions and the averaged conservation laws are satisfied exactly. The reflection and transmission coefficients due to nonlinear shallow water waves are determined implementing two approaches which use Goda's (1976) and Grue's (1992) methods. The results are compared with the existing laboratory experiments, and close agreement is observed overall. Preliminary results of the performance of the breakwater on dissipating storm waves during Hurricane Ike (2008), approaching the shore of Galveston, Texas, are presented.

  15. Periodic jetting and monodisperse jet drops from oblique gas injection

    Science.gov (United States)

    McRae, Oliver; Gaillard, Antoine; Bird, James C.

    2017-07-01

    When air is blown in a straw or tube near an air-liquid interface, typically one of two behaviors is observed: a dimple in the liquid's surface, or a frenzy of sputtering bubbles, waves, and spray. Here we report and characterize an intermediate regime that can develop when a confined air jet enters the interface at an angle. This regime is oscillatory with a distinct characteristic frequency and can develop periodic angled jets that can break up into monodisperse aerosols. The underlying mechanisms responsible for this highly periodic regime are not well understood. Here we flow a continuous stream of gas through a tube near a liquid surface, observing both optically and acoustically the deformation of the liquid-air interface as various parameters are systematically adjusted. We show that the Kelvin-Helmholtz instability is responsible for the inception of waves within a cavity formed by the gas. Inertia, gravity, and capillary forces both shape the cavity and govern the frequency and amplitude of these gas-induced cavity waves. The flapping cavity focuses the waves into a series of periodic jets that can break up into droplets following the Rayleigh-Plateau instability. We present scaling arguments to rationalize the fundamental frequencies driving this system, as well as the conditions that bound the periodic regime. These frequencies and conditions compare well with our experimental results.

  16. Production of jet fuel from alternative source

    Energy Technology Data Exchange (ETDEWEB)

    Eller, Zoltan; Papp, Anita; Hancsok, Jenoe [Pannonia Univ., Veszprem (Hungary). MOL Dept. of Hydrocarbon and Coal Processing

    2013-06-01

    Recent demands for low aromatic content jet fuels have shown significant increase in the last 20 years. This was generated by the growing of aviation. Furthermore, the quality requirements have become more aggravated for jet fuels. Nowadays reduced aromatic hydrocarbon fractions are necessary for the production of jet fuels with good burning properties, which contribute to less harmful material emission. In the recent past the properties of gasolines and diesel gas oils were continuously severed, and the properties of jet fuels will be more severe, too. Furthermore, it can become obligatory to blend alternative components into jet fuels. With the aromatic content reduction there is a possibility to produce high energy content jet fuels with the desirable properties. One of the possibilities is the blending of biocomponents from catalytic hydrogenation of triglycerides. Our aim was to study the possibilities of producing low sulphur and aromatic content jet fuels in a catalytic way. On a CoMo/Al{sub 2}O{sub 3} catalyst we studied the possibilities of quality improving of a kerosene fraction and coconut oil mixture depending on the change of the process parameters (temperature, pressure, liquid hourly space velocity, volume ratio). Based on the quality parameters of the liquid products we found that we made from the feedstock in the adequate technological conditions products which have a high smoke point (> 35 mm) and which have reduced aromatic content and high paraffin content (90%), so these are excellent jet fuels, and their stack gases damage the environment less. (orig.)

  17. Jet in jet in M87

    Science.gov (United States)

    Sob'yanin, Denis Nikolaevich

    2017-11-01

    New high-resolution Very Long Baseline Interferometer observations of the prominent jet in the M87 radio galaxy show a persistent triple-ridge structure of the transverse 15-GHz profile with a previously unobserved ultra-narrow central ridge. This radio structure can reflect the intrinsic structure of the jet, so that the jet as a whole consists of two embedded coaxial jets. A relativistic magnetohydrodynamic model is considered in which an inner jet is placed inside a hollow outer jet and the electromagnetic fields, pressures and other physical quantities are found. The entire jet is connected to the central engine that plays the role of a unipolar inductor generating voltage between the jets and providing opposite electric currents, and the charge neutrality and current closure together with the electromagnetic fields between the jets can contribute to the jet stabilization. The constant voltage is responsible for the similar widening laws observed for the inner and outer jets. This jet-in-jet structure can indicate simultaneous operation of two different jet-launching mechanisms, one relating to the central supermassive black hole and the other to the surrounding accretion disc. An inferred magnetic field of 80 G at the base is sufficient to provide the observed jet luminosity.

  18. Direct patterning using aerodynamically assisted electrohydrodynamic jet printing

    Science.gov (United States)

    Hwang, Sangyeon; Seong, Baekhoon; Lee, Wonyoung; Byun, Doyoung

    2014-11-01

    Electrical force and aerodynamic force are considered to be preferred sources for generating a liquid jet to emit the target fluid on a tiny scale. The former is known as an electrohydrodynamic (EHD) jet, while the latter is called flow focusing. Here, we report the effect of a combined energy source on the micro scale jet and patterns and investigate the scaling law of pattern width according to the ratio of two energy sources. In a conventional EHD jet, after a short length of straight section the charged viscous jet turns into complex shape which occurs difficulty in patterning fine lines. A coaxially driven gas stream smoothed the asymmetric jet lengthening the straight section of the jet. The jet could be issued constantly within the range that did not exceed the stable region in the parametric space. Under such stable conditions, the jet became narrow as compared to the one from the normal EHD jet. Hence, the patterns formed at a high gas pressure were noticeably smaller than the others, demonstrating the controllability of jet thickness. Various liquids had been used as the target fluids to investigate the effect of liquid properties. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (Grand Number: 2014-023284.

  19. IODINE REMOVAL EFFICIENCY IN NON-SUBMERGED AND SUBMERGED SELF-PRIMING VENTURI SCRUBBER

    OpenAIRE

    Ali, Majid; CHANGQI, YAN; ZHONGNING, SUN; HAIFENG, GU; JUNLONG, WANG; MEHBOOB, KHURRAM

    2013-01-01

    The objective of this conducted research is to study the iodine removal efficiency in a self-priming venturi scrubber for submerged and non-submerged operating conditions experimentally and theoretically. The alkaline solution is used as an absorbent, which is prepared by dissolving sodium hydroxide (NaOH) and sodium thiosulphate (Na2S2O3) in water to remove the gaseous iodine (I2) from the gas. Iodine removal efficiency is examined at various gas flow rates and inlet concentrations of iodine...

  20. Enhancement of focused jets by using surface microbubbles

    Science.gov (United States)

    Yukisada, Ryosuke; Kiyama, Akihito; Zhang, Xuehua; Tagawa, Yoshiyuki

    2017-11-01

    Focused liquid jets are important for various key technologies, such as material deposition and automated pipetting. It has been challenging to create high speed jets of viscous liquids. Our latest work showed that it is possible to generate viscous jets by applying sudden acceleration to the liquid (Onuki et al., J. J. Multi. Flow, 2015). It was observed that under certain conditions cavitation bubbles form in the liquid, making important contribution to the increment of jet velocity (Kiyama et al., JFM, 2016). The increased velocity depends on the maximum size of expanding bubbles. Thus, for controlling the velocity of focused jets, it is crucial to control the bubble expansion. In this study, we investigate the effects of surface microbubbles on the focused jets. Before the impact is performed, the microbubbles are produced on an inner wall of the liquid container by using water-ethanol exchange technique. We experimentally measure the jet velocity and bubble motion utilizing a high-speed camera. It is found that surface microbubbles expand upon the impact, enhancing the increment of jet velocity under the conditions that do not trigger cavitation inception in the bulk liquid. JSPS KAKENHI Grant Numbers 26709007 and 17H01246.

  1. Submergence tolerance in Hordeum marinum

    DEFF Research Database (Denmark)

    Pedersen, Ole; Malik, Al I.; Colmer, Timothy D.

    2010-01-01

    Floodwaters differ markedly in dissolved CO(2), yet the effects of CO(2) on submergence responses of terrestrial plants have rarely been examined. The influence of dissolved CO(2) on underwater photosynthesis and growth was evaluated for three accessions of the wetland plant Hordeum marinum Huds......) movement, would all contribute to submergence tolerance in H. marinum. The present study demonstrates that dissolved CO(2) levels can determine submergence tolerance of terrestrial plants. So, submergence experiments should be conducted with defined CO(2) concentrations and enrichment might be needed...

  2. Calibration of submerged multi-sluice gates

    Directory of Open Access Journals (Sweden)

    Mohamed F. Sauida

    2014-09-01

    The main objective of this work is to study experimentally and verify empirically the different parameters affecting the discharge through submerged multiple sluice gates (i.e., the expansion ratios, gates operational management, etc.. Using multiple regression analysis of the experimental results, a general equation for discharge coefficient is developed. The results show, that the increase in the expansion ratio and the asymmetric operation of gates, give higher values for the discharge coefficient. The obtained predictions of the discharge coefficient using the developed equations are compared to the experimental data. The present developed equations showed good consistency and high accuracy.

  3. Development of a ROV Deployed Video Analysis Tool for Rapid Measurement of Submerged Oil/Gas Leaks

    Energy Technology Data Exchange (ETDEWEB)

    Savas, Omer [Univ. of California, Berkeley, CA (United States)

    2017-04-03

    Expanded deep sea drilling around the globe makes it necessary to have readily available tools to quickly and accurately measure discharge rates from accidental submerged oil/gas leak jets for the first responders to deploy adequate resources for containment. We have developed and tested a field deployable video analysis software package which is able to provide in the field sufficiently accurate flow rate estimates for initial responders in accidental oil discharges in submarine operations. The essence of our approach is based on tracking coherent features at the interface in the near field of immiscible turbulent jets. The software package, UCB_Plume, is ready to be used by the first responders for field implementation. We have tested the tool on submerged water and oil jets which are made visible using fluorescent dyes. We have been able to estimate the discharge rate within 20% accuracy. A high end WINDOWS laptop computer is suggested as the operating platform and a USB connected high speed, high resolution monochrome camera as the imaging device are sufficient for acquiring flow images under continuous unidirectional illumination and running the software in the field. Results are obtained over a matter of minutes.

  4. Jet stability in the lithium fall reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.W.

    1978-05-04

    A preliminary analysis has been made of the various hydrodynamic aspects involved in the stability of a liquid-lithium jet in a laser-fusion reactor, which comprises a part of LLL's laser fusion power-generation concept. Various physical factors that may affect the jet breakup are delineated, and some approximate calculations are performed to determine their relative influences. Areas of uncertainty are pointed out, along with plans for experimental verification or further theoretical analysis.

  5. Life-Cycle Energy Use and Greenhouse Gas Emissions Analysis for Bio-Liquid Jet Fuel from Open Pond-Based Micro-Algae under China Conditions

    Directory of Open Access Journals (Sweden)

    Xiliang Zhang

    2013-09-01

    Full Text Available A life-cycle analysis (LCA of greenhouse gas (GHG emissions and energy use was performed to study bio-jet fuel (BJF production from micro-algae grown in open ponds under Chinese conditions using the Tsinghua University LCA Model (TLCAM. Attention was paid to energy recovery through biogas production and cogeneration of heat and power (CHP from the residual biomass after oil extraction, including fugitive methane (CH4 emissions during the production of biogas and nitrous oxide (N2O emissions during the use of digestate (solid residue from anaerobic digestion as agricultural fertilizer. Analyses were performed based on examination of process parameters, mass balance conditions, material requirement, energy consumptions and the realities of energy supply and transport in China (i.e., electricity generation and heat supply primarily based on coal, multiple transport modes. Our LCA result of the BJF pathway showed that, compared with the traditional petrochemical pathway, this new pathway will increase the overall fossil energy use and carbon emission by 39% and 70%, respectively, while decrease petroleum consumption by about 84%, based on the same units of energy service. Moreover, the energy conservation and emission reduction benefit of this new pathway may be accomplished by two sets of approaches: wider adoption of low-carbon process fuels and optimization of algae cultivation and harvest, and oil extraction processes.

  6. Rich phenomenology encountered when two jets collide in microgravity

    Science.gov (United States)

    Suñol, Francesc; Gonzalez-Cinca, Ricard

    The collision between two impinging liquid jets has been experimentally studied in the low gravity environment provided by the ZARM drop tower. The effects of impact angle and liquid flow rate on the collision between like-doublet jets have been considered. Tests were carried out with distilled water injected through nozzles with an internal diameter of 0.7 mm into a test cell. Impact angle varied between 10(°) and 180(°) (frontal collision), while the liquid flow rate ranged between 20 ml/min and 80 ml/min for each nozzle. Such a large parameter range allowed us to observe different phenomena resulting from the jets collision: oscillating droplets attached to the nozzles, a non-uniform spatial distribution of bouncing droplets, coalescing droplets generating a single central droplet, coalescing jets, bouncing jets, liquid chains and liquid sheets. A map of the different patterns observed has been obtained. We present results on the structure of the jets after collision, the breakup length and the size of the generated droplet. The resulting structure of impinging jets highly depends on the Reynolds and Weber numbers, and the proper alignment of the colliding jets.

  7. Mathematical investigation of tsunami-like long waves interaction with submerge dike of different thickness

    Science.gov (United States)

    Zhiltsov, Konstantin; Kostyushin, Kirill; Kagenov, Anuar; Tyryshkin, Ilya

    2017-11-01

    This paper presents a mathematical investigation of the interaction of a long tsunami-type wave with a submerge dike. The calculations were performed by using the freeware package OpenFOAM. Unsteady two-dimensional Navier-Stokes equations were used for mathematical modeling of incompressible two-phase medium. The Volume of Fluid (VOF) method is used to capture the free surface of a liquid. The effects caused by long wave of defined amplitude motion through a submerged dike of varying thickness were discussed in detail. Numerical results show that after wave passing through the barrier, multiple vortex structures were formed behind. Intensity of vortex depended on the size of the barrier. The effectiveness of the submerge barrier was estimated by evaluating the wave reflection and transmission coefficients using the energy integral method. Then, the curves of the dependences of the reflection and transmission coefficients were obtained for the interaction of waves with the dike. Finally, it was confirmed that the energy of the wave could be reduced by more than 50% when it passed through the barrier.

  8. Damage detection in submerged plates using ultrasonic guided waves

    Indian Academy of Sciences (India)

    Suitable ultrasonic guided wave modes with optimum scanning capabilities have been generated and identified in submerged plate system. Finally, the propagation of selected modes through submerged notched plates is investigated. Sensitivity of leaky waves to the notches has been studied. The methodology would help ...

  9. Automating a submerged pump method for operating oil wells

    Energy Technology Data Exchange (ETDEWEB)

    Popa, I.

    1984-01-01

    The basic parameters of wells which operate in a mode of submerged operation are presented. The basic systems for measuring and testing the parameters of submerged operation are described. Worldwide experience in solving this particular problem is analyzed. Romanian (SRR) use of systems for automation, remote signaling and remote management is examined.

  10. Impacts of climate change on submerged and emergent wetland plants

    Science.gov (United States)

    Frederick T. Short; Sarian Kosten; Pamela A. Morgan; Sparkle L Malone; Gregg E. Moore

    2016-01-01

    Submerged and emergent wetland plant communities are evaluated for their response to global climate change (GCC), focusing on seagrasses, submerged freshwater plants, tidal marsh plants, freshwater marsh plants and mangroves. Similarities and differences are assessed in plant community responses to temperature increase, CO2increase, greater UV-B exposure, sea...

  11. Identification of a novel submergence response gene regulated by ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2016-12-07

    Dec 7, 2016 ... 3Engineering Research Center of Ecology and Agricultural Use of Wetland, Ministry of Education, Yangzte University,. Jingzhou 434025, P.R. .... intolerance to submergence) and M202(Sub1A) by qRT-. PCR. We identified a novel gene responsive to submergence, called RS1. The expression patterns of.

  12. Identification of a novel submergence response gene regulated by ...

    African Journals Online (AJOL)

    Our results also show that RS1 is highly expressed under submergence, drought, and NaCl stresses, but not under cold or dehydration stress. Hormone ABA treatment induces, whereas GA treatment decreases, RS1 expression. The RS1 and Sub1A genes are co-regulated under submergence. Overexpression of RS1 in ...

  13. Study on the Impact Characteristics of Coherent Supersonic Jet and Conventional Supersonic Jet in EAF Steelmaking Process

    Science.gov (United States)

    Wei, Guangsheng; Zhu, Rong; Cheng, Ting; Dong, Kai; Yang, Lingzhi; Wu, Xuetao

    2018-02-01

    Supersonic oxygen-supplying technologies, including the coherent supersonic jet and the conventional supersonic jet, are now widely applied in electric arc furnace steelmaking processes to increase the bath stirring, reaction rates, and energy efficiency. However, there has been limited research on the impact characteristics of the two supersonic jets. In the present study, by integrating theoretical modeling and numerical simulations, a hybrid model was developed and modified to calculate the penetration depth and impact zone volume of the coherent and conventional supersonic jets. The computational fluid dynamics results were validated against water model experiments. The results show that the lance height has significant influence on the jet penetration depth and jet impact zone volume. The penetration depth decreases with increasing lance height, whereas the jet impact zone volume initially increases and then decreases with increasing lance height. In addition, the penetration depth and impact zone volume of the coherent supersonic jet are larger than those of the conventional supersonic jet at the same lance height, which illustrates the advantages of the coherent supersonic jet in delivering great amounts of oxygen to liquid melt with a better stirring effect compared to the conventional supersonic jet. A newly defined parameter, the k value, reflects the velocity attenuation and the potential core length of the main supersonic jet. Finally, a hybrid model and its modifications can well predict the penetration depth and impact zone volume of the coherent and conventional supersonic jets.

  14. Inclusive Jets in PHP

    CERN Document Server

    Roloff, Philipp

    2014-01-01

    Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

  15. Radial jetting during the impact of compound drops

    Science.gov (United States)

    Zhang, Jia Ming; Li, Er Qiang; Thoroddsen, Sigurdur

    2014-11-01

    Here we report radial jetting behavior during the impact of compound droplet onto a dry solid surface. The size and number of the inner droplets was precisely controlled by a microfluidic device. With the help of high-speed video imaging from both side view and bottom view, intricate and regular horizontal jetting patterns were recorded. The radial jets are formed due to the interaction between the inner droplets and the outer liquid film, and the jet velocity is much higher than the drop impact velocity. The number of inner droplets and their position within the outer droplet were shown to be very important parameters which governed the generation and pattern of the jets. Other parameters such as droplet impact velocity, inner/outer liquid viscosity, density and interfacial tension have also been varied and used to analyze the jetting dynamics. Entrapment of minute air bubbles was also clearly observed.

  16. Jet reconstruction and jet studies in PHENIX

    CERN Document Server

    Iordanova, A

    2012-01-01

    Jets of particles in localized regions of phase space are produced from partonic hard-scatterings of quarks and gluons contained within protons and neutrons. In pp and d+Au collisions the produced jets fragment into many hadrons, which can then be reconstructed in the PHENIX detector. In contrast, jets in heavy-ion collisions (for example Cu+Cu) may propagate through the created hot, dense medium which, in turn, could lower the energy of the jet. This energy loss has several consequences including modification of the expected rate of (final) particle production and jetshapes. By directly studying the jets measured in heavy-ion collisions, we can start to understand the properties of the hot, dense medium. However, the large nonjet backgrounds make such measurements difficult. In this talk, I will discuss the latest PHENIX results involving jets, jet reconstruction and high-pT phenomena in the context of our current understanding of heavy-ion collisions.

  17. Laser-matter Interaction with Submerged Samples

    Energy Technology Data Exchange (ETDEWEB)

    Mariella, R; Rubenchik, A; Norton, M; Donohue, G; Roberts, K

    2010-03-25

    With the long-term goal in mind of investigating if one could possibly design a 'universal solid-sample comminution technique' for debris and rubble, we have studied pulsed-laser ablation of solid samples that were contained within a surrounding fluid. Using pulses with fluences between 2 J and 0.3 J, wavelengths of 351 and 527 nm, and samples of rock, concrete, and red brick, each submerged in water, we have observed conditions in which {micro}m-scale particles can be preferentially generated in a controlled manner, during the laser ablation process. Others have studied laser peening of metals, where their attention has been to the substrate. Our study uses non-metallic substrates and analyzes the particles that are ablated from the process. The immediate impact of our investigation is that laser-comminution portion of a new systems concept for chemical analysis has been verified as feasible.

  18. Submerged arc welding of heavy plate

    Science.gov (United States)

    Wilson, R. A.

    1972-01-01

    The submerged arc process is particularly suitable for heavy plate welding because of its ability to combine very high deposit rates along with excellent quality. It does these things without the smoke and spatter often accompanying other processes. It is available today in several forms that are pointed to the fabricators of heavy sections with long, short or round about welds. Tandem arc full automatic equipment is particularly suitable for those long heavy welds where speed and deposit rate are of the first order. An attachment called long stick-out which makes use of the IR drop on long electrode extensions can be included on this equipment to increase deposition rates 50% or more.

  19. Modeling tabular icebergs submerged in the ocean

    Science.gov (United States)

    Stern, A. A.; Adcroft, A.; Sergienko, O.; Marques, G.

    2017-08-01

    Large tabular icebergs calved from Antarctic ice shelves have long lifetimes (due to their large size), during which they drift across large distances, altering ambient ocean circulation, bottom-water formation, sea-ice formation, and biological primary productivity in the icebergs' vicinity. However, despite their importance, the current generation of ocean circulation models usually do not represent large tabular icebergs. In this study, we develop a novel framework to model large tabular icebergs submerged in the ocean. In this framework, tabular icebergs are represented by pressure-exerting Lagrangian elements that drift in the ocean. The elements are held together and interact with each other via bonds. A breaking of these bonds allows the model to emulate calving events (i.e., detachment of a tabular iceberg from an ice shelf) and tabular icebergs breaking up into smaller pieces. Idealized simulations of a calving tabular iceberg, its drift, and its breakup demonstrate capabilities of the developed framework.

  20. Crassulacean acid metabolism in submerged aquatic plants

    Science.gov (United States)

    Keeley, Jon E.; Sybesme, C.

    1984-01-01

    CO2-fixation in the dark is known to occur in various organs of many plants. However, only in species possessing crassulacean acid metabolism (CAM) does dark CO2-fixation contribute substantially to the carbon economy of the plant. Until very recently CAM was known only from terrestrial species, largely drought adapted succulents. The discovery of CAM in the submerged aquatic fern ally Isoetes howellii (Isoetaceae)(Keeley 1981) adds a new dimension to our understanding of crassulacean acid metabolism. In this paper I will summarize 1) the evidence of CAM in Isoetes howellii, 2) the data on the distribution of CAM in aquatic species, and 3) the work to date on the functional significance of CAM in aquatic species.

  1. Jet energy scale determination in the D0 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V.M. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Abbott, B. [University of Oklahoma, Norman, OK 73019 (United States); Acharya, B.S. [Tata Institute of Fundamental Research, Mumbai (India); Adams, M. [University of Illinois at Chicago, Chicago, IL 60607 (United States); Adams, T. [Florida State University, Tallahassee, FL 32306 (United States); Agnew, J.P. [The University of Manchester, Manchester M13 9PL (United Kingdom); Alexeev, G.D. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Alkhazov, G. [Petersburg Nuclear Physics Institute, St. Petersburg (Russian Federation); Alton, A. [University of Michigan, Ann Arbor, MI 48109 (United States); Askew, A. [Florida State University, Tallahassee, FL 32306 (United States); Atkins, S. [Louisiana Tech University, Ruston, LA 71272 (United States); Augsten, K. [Czech Technical University in Prague, Prague (Czech Republic); Avila, C. [Universidad de los Andes, Bogotá (Colombia); Badaud, F. [LPC, Université Blaise Pascal, CNRS/IN2P3, Clermont (France); Bagby, L.; Baldin, B. [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Bandurin, D.V., E-mail: bandurin@fnal.gov [University of Virginia, Charlottesville, VA 22904 (United States); Banerjee, S. [Tata Institute of Fundamental Research, Mumbai (India); Barberis, E. [Northeastern University, Boston, MA 02115 (United States); Baringer, P. [University of Kansas, Lawrence, KS 66045 (United States); and others

    2014-11-01

    The calibration of jet energy measured in the D0 detector is presented, based on pp{sup ¯} collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. Jet energies are measured using a sampling calorimeter composed of uranium and liquid argon as the passive and active media, respectively. This paper describes the energy calibration of jets performed with γ+jet, Z+jet and dijet events, with jet transverse momentum p{sub T}>6GeV and pseudorapidity range |η|<3.6. The corrections are measured separately for data and simulation, achieving a precision of 1.4–1.8% for jets in the central part of the calorimeter and up to 3.5% for the jets with pseudorapidity |η|=3.0. Specific corrections are extracted to enhance the description of jet energy in simulation and in particular of the effects due to the flavor of the parton originating the jet, correcting biases up to 3–4% in jets with low p{sub T} originating from gluons and up to 6–8% in jets from b quarks.

  2. Jet break-up in nano-suspensions during electrohydrodynamic atomization in the stable cone-jet mode.

    Science.gov (United States)

    Jayasinghe, S N; Edirisinghe, M J

    2005-06-01

    This paper reports jet break-up phenomena, which occurs during the electrohydrodynamic atomization (EHDA) of nano-suspensions. We investigated three ethylene glycol-based near-monodisperse suspensions, containing 30 wt% of SiO2 particles sized at 20, 80 and 120 nm. These suspensions were subjected to electrohydrodynamic atomization in the stable cone-jet mode and the jet break-up in each is discussed and compared with those of liquids reported in the literature.

  3. Workshop on ROVs and deep submergence

    Science.gov (United States)

    The deep-submergence community has an opportunity on March 6 to participate in a unique teleconferencing demonstration of a state-of-the-art, remotely operated underwater research vehicle known as the Jason-Medea System. Jason-Medea has been developed over the past decade by scientists, engineers, and technicians at the Deep Submergence Laboratory at Woods Hole Oceanographic Institution. The U.S. Navy, the Office of the Chief of Naval Research, and the National Science Foundation are sponsoring the workshop to explore the roles that modern computational, communications, and robotics technologies can play in deep-sea oceanographic research.Through the cooperation of Electronic Data Systems, Inc., the Jason Foundation, and Turner Broadcasting System, Inc., 2-1/2 hours of air time will be available from 3:00 to 5:30 PM EST on March 6. Twenty-seven satellite downlink sites will link one operating research vessel and the land-based operation with workshop participants in the United States, Canada, the United Kingdom, and Bermuda. The research ship Laney Chouest will be in the midst of a 3-week educational/research program in the Sea of Cortez, between Baja California and mainland Mexico. This effort is focused on active hydrothermal vents driven by heat flow from the volcanically active East Pacific Rise, which underlies the sediment-covered Guaymas Basin. The project combines into a single-operation, newly-developed robotic systems, state-of-the-art mapping and sampling tools, fiber-optic data transmission from the seafloor, instantaneous satellite communication from ship to shore, and a sophisticated array of computational and telecommunications networks. During the workshop, land-based scientists will observe and participate directly with their seagoing colleagues as they conduct seafloor research.

  4. Submerged membrane distillation for seawater desalination

    KAUST Repository

    Francis, Lijo

    2014-08-11

    A submerged membrane distillation (SMD) process for fresh water production from Red Sea water using commercially available hollow fiber membranes has been successfully employed and compared with the conventional direct contact membrane distillation (DCMD) process. The hollow fiber membranes have been characterized for its morphology using field effect scanning electron microscope. In SMD process, a bunch of hollow fiber membranes are glued together at both ends to get a simplified open membrane module assembly submerged into the coolant tank equipped with a mechanical stirrer. Hot feed stream is allowed to pass through the lumen side of the membrane using a feed pump. Continuous stirring at the coolant side will reduce the temperature and concentration polarization. During the conventional DCMD process, using feed-coolant streams with co-current and counter-current flows has been tested and the results are compared in this study. In SMD process, a water vapor flux of 10.2 kg m-2 h-1 is achieved when using a feed inlet temperature of 80°C and coolant temperature of 20°C. Under the same conditions, during conventional DCMD process, a water vapor flux of 11.6 and 10.1 kg m-2 h-1 were observed during counter-current and co-current flow streams, respectively. Results show that the water production in the SMD process is comparable with the conventional DCMD process, while the feed-coolant flow streams are in the co-current direction. During conventional DCMD operation, a 15% increase in the water production is observed when feed-coolant streams are in the counter-current direction compared to the co-current direction. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  5. Pressure Propagation of Impinging Jet with Cavitation by Numerical Analysis

    Science.gov (United States)

    Kanamori, Daisei; Inoue, Fumihiro; Ohta, Yutaka

    2017-10-01

    In recent years, cavitating jet has attracted attention as an application of water jet technology. In its application, it is important to clarify the jet flow structure and the behavior of bubble cloud collapse. Therefore, in order to visualize the cavitating jet flow structure and elucidate the behavior of collapsing of cavitation bubble clouds, we conducted numerical simulations with gas-liquid two-phase media model. We validated the numerical model by comparing the numerical results with the theoretical and experimental results and had a good agreement. In the case of gas-liquid two-phase free jet, cavitation bubble clouds emit periodically and transfer at a regular speed. And some bubble clouds merge with a preceding bubble clouds. Comparing with liquid single-phase jet, the core region is maintained to the further downstream and we show the usefulness of the cavitating jet. In the case of gas-liquid two-phase impinging jet, after a cavitation bubble cloud collides with wall, it is broken by applying pressure and generates a shock wave. At this time, the impact pressure becomes maximum. Thereafter, the shock wave affects other cavitation bubble clouds and break these. The collapsed cavitation bubble cloud rebounds and collapses again near the collision wall surface.

  6. A Study of CO2 Absorption Using Jet Bubble Column

    Directory of Open Access Journals (Sweden)

    Setiadi Setiadi

    2010-10-01

    Full Text Available The phenomenon of plunging jet gas-liquid contact occurs quite often in nature, it's momentum carries small air bubbles with it into the reactor medium. The momentum of the liquid stream can be sufficient to carry small bubbles completely to the bottom of the vessel. A stream of liquid falling toward a level surface of that liquid will pull the surrounding air along with it. It will indent the surface of the liquid to form a trumpet-like shape. If the velocity of the stream is high enough, air bubbles will be pulled down, i.e. entrained into the liquid. This happens for two main reasons: air that is trapped between the edge of the falling stream and the trumpet-shaped surface profile and is carried below the surface. This study investigates the potential of a vertical liquid plunging jet for a pollutant contained gas absorption technique. The absorber consists of liquid jet and gas bubble dispersed phase. The effects of operating variables such as liquid flowrate, nozzle diameter, separator pressure, etc. on gas entrainment and holdup were investigated. The mass transfer of the system is governed by the hydrodynamics of the system. Therefore a clear and precise understanding of the above is necessary : to characterize liquid and gas flow within the system, 2. Variation in velocity of the jet with the use of different nozzle diameters and flow rates, 3. Relationship between the liquid and entrained airflow rate, 4. Gas entrainment rate and gas void fraction.

  7. Jet Veto Measurements at ATLAS

    CERN Document Server

    Hesketh, Gavin Grant; The ATLAS collaboration

    2017-01-01

    Jet veto cross section measurements in ATLAS ATLAS has no new dedicated analyses on BFKLtype analyses. We suggest the following mixture of jet veto / exclusive jet cross sections in V+jet, VV+jet, multijets: - Z+jets 13 TeV and Jet vetoes in Z VBF, W VBF studies - WW+0,1 jets http://arxiv.org/abs/1608.03086 - Other dibosons + jets: Zgamma+jets and WZ+jets http://arxiv.org/abs/1606.04017,http://arxiv.org/abs/1604.05232 - Studies of rapidity separations etc in 4jet events http://arxiv.org/abs/1509.07335

  8. Interaction of Acoustic Waves with a Cryogenic Nitrogen Jet at Sub- and Supercritical Pressures

    National Research Council Canada - National Science Library

    Chehroudi, B

    2001-01-01

    To better understand the nature of the interaction between acoustic waves and liquid fuel jets in rocket engines, cryogenic liquid nitrogen is injected into a room temperature high-pressure chamber...

  9. Unusual energy properties of leaky backward Lamb waves in a submerged plate.

    Science.gov (United States)

    Nedospasov, I A; Mozhaev, V G; Kuznetsova, I E

    2017-05-01

    It is found that leaky backward Lamb waves, i.e. waves with negative energy-flux velocity, propagating in a plate submerged in a liquid possess extraordinary energy properties distinguishing them from any other type of waves in isotropic media. Namely, the total time-averaged energy flux along the waveguide axis is equal to zero for these waves due to opposite directions of the longitudinal energy fluxes in the adjacent media. This property gives rise to the fundamental question of how to define and calculate correctly the energy velocity in such an unusual case. The procedure of calculation based on incomplete integration of the energy flux density over the plate thickness alone is applied. The derivative of the angular frequency with respect to the wave vector, usually referred to as the group velocity, happens to be close to the energy velocity defined by this mean in that part of the frequency range where the backward mode exists in the free plate. The existence region of the backward mode is formally increased for the submerged plate in comparison to the free plate as a result of the liquid-induced hybridization of propagating and nonpropagating (evanescent) Lamb modes. It is shown that the Rayleigh's principle (i.e. equipartition of total time-averaged kinetic and potential energies for time-harmonic acoustic fields) is violated due to the leakage of Lamb waves, in spite of considering nondissipative media. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. TEST PLAN CHARACTERIZATION OF JET FORCES UPON WASTE TANK COMPONENTS

    Energy Technology Data Exchange (ETDEWEB)

    Bamberger, J. A.

    1992-01-01

    Westinghouse Hanford Company plans to install mixer pumps in double-shell waste tanks to mobilize and suspend settled sludge to allow eventual retrieval for treatment and permanent storage. The mixer pumps produce high momentum, horizontally directed jets that impact and mobilize the sludge and mix it into slurry for removal. There is concern that the force of the jet may damage tank internal components in its path. This test plan describes scaled experiments designed to characterize the velocity profiles of a near floor jet and to quantify the impact farces and drag coefficients of three tank components: radiation dry well, airlift circulator, and steam coil. The experiments will be conducted in water, at approximately 1/6-scale, using one stationary nozzle to simulate the jet. To measure and confirm the velocity profile of the free, submerged jet, the horizontal and vertical velocity profiles will be measured at several distances from the nozzle. The profile will also be measured after the jet impinges upon the tank floor to determine the·extent of the change in the profile caused by impingement. The jet forces upon the test articles will be measured at a maximum of four velocities and a variety of test article orientations. Each orientation will represent a unique position of the test article relative to the jet and the tank floor. In addition, the steam coil will be tested in three rotational orientations because it is not symmetric. The highest jet velocity will be selected so that the Reynolds number of the test article in the model will match that of the prototype when operating at design conditions. The forces measured upon the model components will be used to calculate the force on the prototype components using geometric scaling factors. In addition, the model force measurements will be used to calculate the component's drag coefficient as a function of the component Reynolds number.

  11. Jetting formation of the explosively loaded powders

    Science.gov (United States)

    Xue, Kun; Yu, Qiqi

    2017-10-01

    The formation of jet-like structures is widely reported in the explosive dispersal of powders surrounding high explosive charges. The jetting of powder beds initiates upon the shock wave reaches the outer edge of the charge. Opposed to the interface instability theory, a hollow sphere based bulk fragmentation model is established to account for the jetting of powders. A two-phase process, namely the nucleation and free expansion of hollow spheres, corresponds to the unloading process of the powder compact caused by the rarefaction waves which governs the fragmentation of the powders. The separation between adjacent hollow spheres dictates the size of the particle clusters, which would evolve into particle jets in later times. The predicted breakup time and the size of particle jets agree well with the experimental results. The increased moisture content in powders results in an increased number of particle jets. This moisture effect can be understood in light of the varied energy distribution due to the incompressibility of the interstitial liquids trapped inside the inter-grain pores. The portion of shock energy which is not consumed in the shock compaction of the wet powders would be dissipated through the viscous shear flows during the unloading of the wet powder compact. The excessive viscous energy requires to activate more localized shear flows, accordingly leading to an increased number of particle jets.

  12. Durability performance of submerged concrete structures - phase 2.

    Science.gov (United States)

    2015-09-01

    This project determined that severe corrosion of steel can occur in the submerged : portions of reinforced concrete structures in marine environments. Field studies of decommissioned : pilings from Florida bridges revealed multiple instances of stron...

  13. Submerged Aquatic Vegetation of Bogue Sound, North Carolina 1992 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During 1992, 1:20,000 scale aerial photography for Bogue Sound, North Carolina was collected as part of an effort to map submerged aquatic vegetation (SAV) in...

  14. Submerged Aquatic Vegetation of Bogue Sound, North Carolina 1992 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During 1992, 1:20,000 scale aerial photography for Bogue Sound, North Carolina was collected as part of an effort to map submerged aquatic vegetation (SAV) in...

  15. Marine algal flora of submerged Angria Bank (Arabian Sea)

    Digital Repository Service at National Institute of Oceanography (India)

    Untawale, A.G.; Reddy, C.R.K.; Ambiye, V.

    Submerged Angria Bank was surveyed for the deep water marine algal flora. About 57 species were reported from this bank for the first time. Rhodophyta dominated (30 species) followed by Chlorophyta (18 species) and Phaeophyta (9 species). A few...

  16. Submerged Aquatic Vegetation of Bogue Sound, North Carolina 1992 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During 1992, 1:20,000 scale aerial photography for Bogue Sound, North Carolina was collected as part of an effort to map submerged aquatic vegetation (SAV) in...

  17. Submerged Aquatic Vegetation of Bogue Sound, North Carolina 1992 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — During 1992, 1:20,000 scale aerial photography for Bogue Sound, North Carolina was collected as part of an effort to map submerged aquatic vegetation (SAV) in...

  18. Supporting Calculations For Submerged Bed Scrubber Condensate Disposal Preconceptual Study

    Energy Technology Data Exchange (ETDEWEB)

    Pajunen, A. J.; Tedeschi, A. R.

    2012-09-18

    This document provides supporting calculations for the preparation of the Submerged Bed Scrubber Condensate Disposal Preconceptual Study report The supporting calculations include equipment sizing, Hazard Category determination, and LAW Melter Decontamination Factor Adjustments.

  19. Impeded Carbohydrate Metabolism in Rice Plants under Submergence Stress

    Directory of Open Access Journals (Sweden)

    Malay Kumar ADAK

    2011-06-01

    Full Text Available The detrimental effects of submergence on physiological performances of some rice varieties with special references to carbohydrate metabolisms and their allied enzymes during post-flowering stages have been documented and clarified in the present investigation. It was found that photosynthetic rate and concomitant translocation of sugars into the panicles were both related to the yield. The detrimental effects of the complete submergence were recorded in generation of sucrose, starch, sucrose phosphate synthase and phosphorylase activity in the developing panicles of the plants as compared to those under normal or control (i.e. non-submerged condition. The accumulation of starch was significantly lower in plants under submergence and that was correlated with ADP-glucose pyrophosphorylase activity. Photosynthetic rate was most affected under submergence in varying days of post-flowering and was also related to the down regulation of Ribulose bisphosphate carboxylase activity. However, under normal or control condition, there recorded a steady maintenance of photosynthetic rate at the post-flowering stages and significantly higher values of Ribulose bisphosphate carboxylase activity. Still, photosynthetic rate of the plants under both control and submerged conditions had hardly any significant correlation with sugar accumulation and other enzymes of carbohydrate metabolism like invertase with grain yield. Finally, plants under submergence suffered significant loss of yield by poor grain filling which was related to impeded carbohydrate metabolism in the tissues. It is evident that loss of yield under submergence is attributed both by lower sink size or sink capacity (number of panicles, in this case as well as subdued carbohydrate metabolism in plants and its subsequent partitioning into the grains.

  20. Incipient motion of sediment in presence of submerged flexible vegetation

    OpenAIRE

    Wang, Hao; Tang, Hong-Wu; Zhao, Han-Qing; Xuan-yu ZHAO; Lü, Sheng-qi

    2015-01-01

    The presence of submerged vegetation on river beds can change the water flow structure and alter the state of sediment motion. In this study, the incipient motion of sediment in the presence of submerged flexible vegetation in open channels was investigated in a laboratory experiment. The vegetation was simulated with flexible rubber cylinders arranged in parallel arrays. The effect of the vegetation density, water depth, and sediment grain size on the incipient motion was investigated. The e...

  1. Jets in Active Galaxies

    Indian Academy of Sciences (India)

    tended regions of emission. These jets, which occur across the electromagnetic spectrum, are powered by supermassive black holes in the centres of the host galaxies. Jets are seen on the scale of parsecs in the nuclear regions to those which power the giant radio sources extending over several mega- parsecs. These jets ...

  2. Characteristics and Limitations of Submerged GPS L1 Observations

    Science.gov (United States)

    Steiner, Ladina; Geiger, Alain

    2017-04-01

    Extensive amount of water stored in snow covers has a high impact on flood development during snow melting periods. Early assessment of these parameters in mountain environments enhance early-warning and thus prevention of major impacts. Sub-snow GNSS techniques are lately suggested to determine liquid water content, snow water equivalent or considered for avalanche rescue. This technique is affordable, flexible, and provides accurate and continuous observations independent on weather conditions. However, the characteristics of GNSS observations for applications within a snow-pack still need to be further investigated. The magnitude of the main interaction processes involved for the GPS wavelength propagating through different layers of snow, ice or water is theoretically examined. Liquid water exerts the largest influence on GPS signal propagation through a snow-pack. Therefore, we focus on determining the characteristics of GNSS observables under water. An experiment was set-up to investigate the characteristics and limitations of submerged GPS observations using a pool, a level control by communicating pipes, a geodetic and a low-cost GPS antenna, and a water level sensor. The GPS antennas were placed into the water. The water level was increased daily by a step of two millimeters up to thirty millimeters above the antenna. Based on this experiment, the signal penetration depth, satellite availability, the attenuation of signal strength and the quality of solutions are analyzed. Our experimental results show an agreement with the theoretically derived attenuation parameter and signal penetration depth. The assumption of water as the limiting parameter for GPS observations within a snow-pack can be confirmed. Higher wetness in a snow-pack leads to less transmission, higher refraction, higher attenuation and thus a decreased penetration depth as well as a reduced quality of the solutions. In consequence, GPS applications within a snow-pack are heavily impacted by

  3. Catalytic autothermal reforming of Jet fuel

    Science.gov (United States)

    Lenz, Bettina; Aicher, Thomas

    Aircraft manufacturers have to reduce the emissions and the specific fuel consumption of their systems. Fuel cell use in a 'more electric aircraft' can be one possibility. To keep the technology simple only one fuel (Jet A, Jet A-1) shall be used on board the aircraft. Therefore, the catalytic reforming of Jet A-1 fuel was examined in this paper, although the use of fossil fuels causes the production of greenhouse effect promoting gases like carbon dioxide CO 2. The autothermal reforming of desulphurised kerosene is examined with a 15 kW (based on the lower heating value of Jet fuel) test rig. The experiments are performed at steam to carbon ratios of S/C = 1.5-2.5 and air to fuel ratios of λ = 0.24-0.32, respectively. The composition of the product gas, the volumetric flow rate of the product gas at standard conditions and the temperatures in the catalyst are determined as a function of the operating variables. The gas hourly space velocity (GHSV) is varied between 50,000 and 300,000 h -1. The influence of sulphur containing feed streams (real Jet fuel) on reforming behaviour is investigated as well as the influence of the hydrogen concentration on the hydrodesulphurisation process. Another simple way of desulphurisation is the adsorption of liquid sulphur containing hydrocarbons, the influence of the variation of the liquid hourly space velocity (LHSV) is measured at a temperature of 150 °C.

  4. Submerged cultivation of medicinal mushrooms: bioprocesses and products (review).

    Science.gov (United States)

    Elisashvili, Vladimir

    2012-01-01

    Medicinal mushrooms belonging to higher Basidiomycetes are an immensely rich yet largely untapped resource of useful, easily accessible, natural compounds with various biological activities that may promote human well-being. The medicinal properties are found in various cellular components and secondary metabolites (polysaccharides, proteins and their complexes, phenolic compounds, polyketides, triterpenoids, steroids, alkaloids, nucleotides, etc.), which have been isolated and identified from the fruiting bodies, culture mycelium, and culture broth of mushrooms. Some of these compounds have cholesterol-lowering, anti-diabetic, antioxidant, antitumor, immunomodulating, antimicrobial, and antiviral activities ready for industrial trials and further commercialization, while others are in various stages of development. Recently, the submerged cultivation of medicinal mushrooms has received a great deal of attention as a promising and reproducible alternative for the efficient production of mushroom mycelium and metabolites. Submerged cultivation of mushrooms has significant industrial potential, but its success on a commercial scale depends on increasing product yields and development of novel production systems that address the problems associated with this technique of mushroom cultivation. In spite of many researchers' efforts for the production of bioactive metabolites by mushrooms, the physiological and engineering aspects of submerged cultures are still far from being thoroughly studied. The vast majority of studies have focused on polysaccharide and ganoderic acid production in submerged cultivation of medicinal mushrooms, and very little has been written so far on the antioxidant and hemagglutinating activity of submerged mushroom cultures. The purpose of this review is to provide an update of the present state of the art and future prospects of submerged cultivation of medicinal mushrooms to produce mycelium and bioactive metabolites, and to make a

  5. Jet substructure in ATLAS

    CERN Document Server

    Miller, David W

    2011-01-01

    Measurements are presented of the jet invariant mass and substructure in proton-proton collisions at $\\sqrt{s} = 7$ TeV with the ATLAS detector using an integrated luminosity of 37 pb$^{-1}$. These results exercise the tools for distinguishing the signatures of new boosted massive particles in the hadronic final state. Two "fat" jet algorithms are used, along with the filtering jet grooming technique that was pioneered in ATLAS. New jet substructure observables are compared for the first time to data at the LHC. Finally, a sample of candidate boosted top quark events collected in the 2010 data is analyzed in detail for the jet substructure properties of hadronic "top-jets" in the final state. These measurements demonstrate not only our excellent understanding of QCD in a new energy regime but open the path to using complex jet substructure observables in the search for new physics.

  6. Numerical simulation of liquid round jet atomization

    Science.gov (United States)

    Jarrahbashi, Dorrin; Sirignano, William A.; Popov, Pavel P.; Hussain, Fazle

    2017-09-01

    This paper is associated with a poster winner of a 2016 APS/DFD Gallery of Fluid Motion Award for work presented at the DFD Gallery of Fluid Motion. The original poster is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.P0009

  7. Simulation of the pressure field near a jet by randomly distributed vortex rings

    Science.gov (United States)

    Fung, Y. T.; Liu, C. H.; Gunzburger, M. D.

    1979-01-01

    Fluctuations of the pressure field in the vicinity of a jet are simulated numerically by a flow model consisting of axially symmetric vortex rings with viscous cores submerged in a uniform stream. The time interval between the shedding of successive vortices is taken to be a random variable with a probability distribution chosen to match that from experiments. It is found that up to 5 diameters downstream of the jet exit, statistics of the computed pressure field are in good agreement with experimental results. Statistical comparisons are provided for the overall sound pressure level, the peak amplitude, and the Strouhal number based on the peak frequency of the pressure signals.

  8. Experimental study of flat plate cooling using draft induced by a submerged radial jet

    Directory of Open Access Journals (Sweden)

    Argemiro Palencia-Diaz

    2017-01-01

    Full Text Available Una investigación experimental se ha llevado a cabo para evaluar la transferencia de calor en una configuración modificada de un chorro radial sumergido, por medio del cual se puede extraer el fluido directamente debajo de la boquilla, en busca de una mejora en la velocidad de transferencia de calor. Los experimentos se llevaron a cabo para las siguientes gamas de parámetros que rigen el fenómeno: boquilla de 16 mm de diámetro, distancia entre boquilla y placa entre 10 mm a 20 mm, número de Reynolds que oscila entre 10.000 y 20.000, y calor de 10,2 – 13,6 kW/m2. La transferencia de calor se estima a través de la distribución de temperatura obtenida por medio de un dispositivo de adquisición de datos y un apropiado post-procesamiento, lo que hace posible determinar el coeficiente de transferencia de calor y el número de Nusselt para las diferentes condiciones en estudio. El uso de la extracción de fluido a través de tiro inducido genera un aumento significativo en la transferencia de calor en el área debajo de la boquilla, obteniendo valores desde 290 hasta 1500 W/m2.°C.

  9. Unsteady behavior of a confined jet in a cavity at moderate Reynolds numbers

    Energy Technology Data Exchange (ETDEWEB)

    Bouchet, G [Laboratoire IUSTI, UMR 7343 CNRS, Aix Marseille Universite, 5 rue Enrico Fermi, 13453 Marseille Cedex 13 (France); Climent, E, E-mail: Gilles.Bouchet@univ-amu.fr, E-mail: Gilles.Bouchet@univ-provence.fr, E-mail: climent@imft.fr [Institut de Mecanique des Fluides de Toulouse, UMR 5502 Universite de Toulouse-CNRS-INPT-UPS, 1 allee du Professeur Camille Soula, 31400 Toulouse (France)

    2012-04-01

    Self-sustained oscillations in the sinuous mode are observed when a jet impinges on a rigid surface. Confined jet instability is experimentally and numerically investigated here at moderate Reynolds numbers. When the Reynolds number is varied, the dynamic response of the jet is unusual in comparison with that of similar configurations (hole-tone, jet edge, etc). Modal transitions are clearly detected when the Reynolds number is varied. However, these transitions result in a reduction of the frequency, which means that the wavelength grows with Reynolds number. Moreover, the instability that sets in at low Reynolds number, as a subcritical Hopf bifurcation, disappears only 25% above the threshold. Then, the flow becomes steady again and symmetric. This atypical behavior is compared with our previous study on a submerged fountain (Bouchet et al 2002 Europhys. Lett. 59 826). (paper)

  10. Rice SUB1A constrains remodelling of the transcriptome and metabolome during submergence to facilitate post-submergence recovery.

    Science.gov (United States)

    Locke, Anna M; Barding, Gregory A; Sathnur, Sumukh; Larive, Cynthia K; Bailey-Serres, Julia

    2017-11-02

    The rice (Oryza sativa L.) ethylene-responsive transcription factor gene SUB1A-1 confers tolerance to prolonged, complete submergence by limiting underwater elongation growth. Upon desubmergence, SUB1A-1 genotypes rapidly recover photosynthetic function and recommence development towards flowering. The underpinnings of the transition from stress amelioration to the return to homeostasis are not well known. Here, transcriptomic and metabolomic analyses were conducted to identify mechanisms by which SUB1A improves physiological function over the 24 hr following a sublethal submergence event. Evaluation of near-isogenic genotypes after submergence and over a day of reaeration demonstrated that SUB1A transiently constrains the remodelling of cellular activities associated with growth. SUB1A influenced the abundance of ca. 1,400 transcripts and had a continued impact on metabolite content, particularly free amino acids, glucose, and sucrose, throughout the recovery period. SUB1A promoted recovery of metabolic homeostasis but had limited influence on mRNAs associated with growth processes and photosynthesis. The involvement of low energy sensing during submergence and recovery was supported by dynamics in trehalose-6-phosphate and mRNAs encoding key enzymes and signalling proteins, which were modulated by SUB1A. This study provides new evidence of convergent signalling pathways critical to the rapidly reversible management of carbon and nitrogen metabolism in submergence resilient rice. © 2017 John Wiley & Sons Ltd.

  11. Jet dynamics and stability

    Directory of Open Access Journals (Sweden)

    Perucho M.

    2013-12-01

    Full Text Available The dynamics and stability of extragalactic jets may be strongly influenced by small (and probable di_erences in pressure between the jet and the ambient and within the jet itself. The former give rise to expansion and recollimation of the jet. This occurs in the form of conical shocks, or Mach disks, if the pressure di_erence is large enough. Pressure asymmetries within the jet may trigger the development of helical patterns via coupling to kink current-driven instability, or to helical Kelvin-Helmholtz instability, depending on the physical conditions in the jet. I summarize here the evidence collected during the last years on the presence of recollimation shocks and waves in jets. In the jet of CTA 102 evidence has been found for (travelingshock-(standingshock interaction in the core-region (0.1 mas from the core, using information from the light-curve of the source combined with VLBI data. The conclusions derived have been confirmed by numerical simulations combined with emission calculations that have allowed to study the spectral evolution of the perturbed jet. Helical structures can also be identified in radio-jets. The ridge-line of emission of the jet of S5 0836+710 has been identified as a physical structure corresponding to a wave developing in the jet flow. I review here the evidence that has allowed to reach this conclusion, along with an associated caveat. Current data do not allow to distinguish between magnetic or hydrodynamical instabilities. I finally discuss the importance of these linear and non-linear waves for jet evolution.

  12. Peculiarities of thermal dissociation of oxides during submerged arc welding

    Directory of Open Access Journals (Sweden)

    Leonid Zhdanov

    2013-12-01

    Full Text Available A method of settlement of the process of thermal dissociation of oxides in reaction zone during the submerged arc welding and welding deposition is presented. Combined non-linear equations for definition of gas-vapour mixture composition were developed. They describe the dissociation of MeO, MeO2 and Me2O3 types of oxides. Calculations of the processes of oxide dissociation were performed for the oxides that are commonly included into welding fluxes. Their results and analysis are presented. The method proposed appeared to be adequate and applicable for analysis of processes during submerged arc operation that run in the gas phase.

  13. EAARL-B Submerged Topography—Saint Croix, U.S. Virgin Islands, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A submerged topography digital elevation model (DEM) mosaic for a portion of the submerged environs of Saint Croix, U.S. Virgin Islands, was produced from remotely...

  14. EAARL-B Submerged Topography--Saint Thomas, U.S. Virgin Islands, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A submerged topography Digital Elevation Model (DEM) mosaic for a portion of the submerged environs of Saint Thomas, U.S. Virgin Islands, was produced from remotely...

  15. Long-term allelopathic control of phytoplankton by the submerged macrophyte Elodea nuttallii

    NARCIS (Netherlands)

    Vanderstukken, M.; Declerck, S.A.J.; Decaestecker, E.; Muylaert, K.

    2014-01-01

    Keywords: allelochemicals; chemical ecology; competition; nutrient limitation; shallow lakes Summary 1.It is well known that submerged macrophytes can suppress phytoplankton blooms in lakes and thus promote water quality and biodiversity. One of the possible mechanisms through which submerged

  16. Invasive Crayfish Threaten the Development of Submerged Macrophytes in Lake Restoration

    NARCIS (Netherlands)

    Wal, van der J.E.M.; Dorenbosch, M.; Immers, A.K.; Vidal Forteza, C.; Geurts Van Kessel, J.M.M.; Peeters, E.T.H.M.; Koese, B.; Bakker, E.S.

    2013-01-01

    Submerged macrophytes enhance water transparency and aquatic biodiversity in shallow water ecosystems. Therefore, the return of submerged macrophytes is the target of many lake restoration projects. However, at present, north-western European aquatic ecosystems are increasingly invaded by omnivorous

  17. Invasive crayfish threaten the development of submerged macrophytes in lake restoration

    NARCIS (Netherlands)

    Van der Wal, J.E.M.; Dorenbosch, M.; Immers, A.; Vidal Forteza, C.; Geurts, J.J.M.; Peeters, E.T.H.M.; Koese, B.; Bakker, E.S.

    2013-01-01

    Submerged macrophytes enhance water transparency and aquatic biodiversity in shallow water ecosystems. Therefore, the return of submerged macrophytes is the target of many lake restoration projects. However, at present, north-western European aquatic ecosystems are increasingly invaded by omnivorous

  18. What ignites optical jets?

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian Jester

    2002-12-23

    The properties of radio galaxies and quasars with and without optical or X-ray jets are compared. The majority of jets from which high-frequency emission has been detected so far (13 with optical emission, 11 with X-rays, 13 with both) are associated with the most powerful radio sources at any given redshift. It is found that optical/X-ray jet sources are more strongly beamed than the average population of extragalactic radio sources. This suggests that the detection or non-detection of optical emission from jets has so far been dominated by surface brightness selection effects, not by jet physics. It implies that optical jets are much more common than is currently appreciated.

  19. Through-flow of water in leaves of a submerged plant is influenced by the apical opening

    DEFF Research Database (Denmark)

    Pedersen, Ole; Jørgensen, Lise Bolt; Sand-Jensen, Kaj

    1997-01-01

    Submerged plant, apical opening, hydathode, Sparganium, hydraulic architecture, leaf specific conductivity......Submerged plant, apical opening, hydathode, Sparganium, hydraulic architecture, leaf specific conductivity...

  20. The remarkable AGN jets

    Science.gov (United States)

    Komissarov, Serguei

    The jets from active galactic nuclei exhibit stability which seems to be far superior compared to that of terrestrial and laboratory jets. They manage to propagate over distances up to a billion of initial jet radii. Yet this may not be an indication of some exotic physics but mainly a reflection of the specific environment these jets propagate through. The key property of this environment is a rapid decline of density and pressure along the jet, which promotes its rapid expansion. Such an expansion can suppress global instabilities, which require communication across the jet, and hence ensure its survival over huge distances. At kpc scales, some AGN jets do show signs of strong instabilities and even turn into plumes. This could be a result of the flattening of the external pressure distribution in their host galaxies or inside the radio lobes. In this regard, we discuss the possible connection between the stability issue and the Fanaroff-Riley classification of extragalactic radio sources. The observations of AGN jets on sub-kpc scale do not seem to support their supposed lack of causal connectivity. When interpreted using simple kinematic models, they reveal a rather perplexing picture with more questions than answers on the jets dynamics.

  1. The hydrogen laminar jet

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Sanz, M. [Departamento de Motopropulsion y Termofluidomecanica, ETSI Aeronauticos, Universidad Politecnica de Madrid, 28040 Madrid (Spain); Rosales, M. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain); Instituto de Innovacion en Mineria y Metalurgia, Avenida del Valle 738, Santiago (Chile); Sanchez, A.L. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain)

    2010-04-15

    Numerical and asymptotic methods are used to investigate the structure of the hydrogen jet discharging into a quiescent air atmosphere. The analysis accounts in particular for the variation of the density and transport properties with composition. The Reynolds number of the flow R{sub j}, based on the initial jet radius a, the density {rho}{sub j} and viscosity {mu}{sub j} of the jet and the characteristic jet velocity u{sub j}, is assumed to take moderately large values, so that the jet remains slender and stable, and can be correspondingly described by numerical integration of the continuity, momentum and species conservation equations written in the boundary-layer approximation. The solution for the velocity and composition in the jet development region of planar and round jets, corresponding to streamwise distances of order R{sub j}a, is computed numerically, along with the solutions that emerge both in the near field and in the far field. The small value of the hydrogen-to-air molecular weight ratio is used to simplify the solution by considering the asymptotic limit of vanishing jet density. The development provides at leading-order explicit analytical expressions for the far-field velocity and hydrogen mass fraction that describe accurately the hydrogen jet near the axis. The information provided can be useful in particular to characterize hydrogen discharge processes from holes and cracks. (author)

  2. Nitrification with submerged filters. Air supply and comsumption at the pilot-plant at the Bekkelaget treatment plant

    OpenAIRE

    Englund, G

    1990-01-01

    During the three months research period (October 1989 - January 1990) the average nitrification efficiencies for municipal sewage were 48% and 61 % for respectively one-step and two-step biological submerged filters placed after chemical precipitation. Correspondi- ng nitrification rates were 0.69 and 0.56 g NH4-N/m² d. The air/liquid ratio (m³/m³) varied from 18-35 for the diffused aeration, giving high 02-concentrations, but indicating an inefficient aeration system. No logging problems occ...

  3. Hydrogen mitigation in submerged arc welding

    Science.gov (United States)

    Klimowicz, Steven

    With the role of hydrogen in weld metal well understood in its relation to cold cracking, there has been a push to produce welds with lower and lower diffusible hydrogen contents. The push for lower diffusible hydrogen contents has placed pressure on consumables manufactures to create consumables that can achieve the requirements for lower diffusible hydrogen content. Currently EM12K flux is produced so that it can achieve below 4 ml of diffusible hydrogen for every 100g of weld metal deposited (ml/100g) for submerged arc welding (SAW). The recent trend for industry is to preferentially achieve diffusible hydrogen contents below 3 ml/100g. Making it necessary to find a way to modify the flux to achieve a lower diffusible hydrogen content for the welds it produces. To achieve this goal a two phase plan was developed. The first phase was to characterize the entire welding system for hydrogen. Since the goal of the project is hydrogen mitigation, any amount of hydrogen that could be reduced is helpful and therefore must first be discovered. Sources of hydrogen may be found by analyzing the welding wire and base metal, as well as breaking the flux down into its components and production steps. The wire was analyzed for total hydrogen content as was the base metal. The flux and its components were analyzed using differential thermal analysis-simultaneous thermal analysis (DTA-STA) and later vacuum degassing for moisture content. The analysis of the wire showed that the copper coating on the wire was the largest contributor of hydrogen. There was lubricant present on the wire surface as well, but it did not contribute as much as the copper coating. It was found that a simple low temperature baking of the wire was enough to remove the lubricant and coating moisture. The base metal was found to have a similar total hydrogen content to that of the wire. The breakdown of the flux and production process for moisture content analysis revealed that the production process

  4. Design and construction of triplet atmospheric cold plasma jet for sterilization

    Directory of Open Access Journals (Sweden)

    F. Sohbatzadeh

    2014-03-01

    Full Text Available In this paper, construction of triplet atmospheric plasma jet using argon, air, oxygen and nitrogen gases is reported. Bactericidal effect of the plasma jet is also investigated. To that end, longitudinal geometric configuration for the electrodes was chosen because it would increase the jet length. Electrical characteristics, jet length dependencies on the applied voltage and gas flow rate were decided, experimentally. Relative concentrations of chemical reactive species such as ozone, atomic oxygen, NOx compounds and hydroxyl were measured using optical emission spectroscopy. It was seen that atomic oxygen and ozone concentrations with triplet plasma jet are more than the concentration of single plasma jet. Triplet plasma jet was also used for sterilization of solid and liquid surfaces to disinfect gram-negative and gram-positive Escherichia coli and Streptococcus pyogenes bacteria. The results verified the effectiveness of the triplet plasma jet for killing bacteria.

  5. Background Effects on Jet Detection in Heavy Ion Collisions

    Science.gov (United States)

    Aukerman, Alexander; Hughes, Charles; Krobatch, Thomas; Matyja, Adam; Nattrass, Christine; Neuhas, James; Sorensen, Soren; Witt, Will

    2017-09-01

    Heavy ion collisions performed at the LHC and RHIC at large energy scales produce a liquid of quarks and gluons known as a Quark-Gluon Plasma (QGP). Jets, which are collimated bunches of particles emitted from highly energetic partons, are produced at the early stages of these collisions, and can provide information about the properties of the QGP. Partonic energy loss in the medium can by quantified by measurements of fragmentation functions. However, the high background energies resulting from emissions uncorrelated to the initial hard scatterings in the heavy ion collisions place limitations on jet detection methods and fragmentation measurements. For the purpose of investigating the limitations on these current jet detection methods we generated a heavy ion background based on charged hadron data. We explore the behavior of a jet finding algorithm with our generated background to examine how the presence of a heavy ion background may affect the measurements of jet properties.

  6. Proposed gas generation assembly would recover deeply submerged objects

    Science.gov (United States)

    Sprague, C. W.

    1968-01-01

    Gas generation system, used for recovery of submerged objects, generates hydrogen gas by the reaction of sodium with sea water. The assembly consists of flooded flotation tanks cabled together, equipped with relief valves to equalize pressure as the array ascends and hydrostatic pressure diminishes, and carrying remotely activated welding units.

  7. Implementation of Submerged Arc Welding Training. Final Report.

    Science.gov (United States)

    Bowick, Earl; Todd, John

    A unit on submerged arc welding (SAW) was developed and integrated into the welding program at Seattle Central Community College (Washington) during the period December 1983 through May 1984. During this time, 10 major users of SAW in the area were contacted and mailed questionnaires. Follow up consisted of telephone calls and personal contact as…

  8. Benthic Bacterial Diversity in Submerged Sinkhole Ecosystems▿ †

    Science.gov (United States)

    Nold, Stephen C.; Pangborn, Joseph B.; Zajack, Heidi A.; Kendall, Scott T.; Rediske, Richard R.; Biddanda, Bopaiah A.

    2010-01-01

    Physicochemical characterization, automated ribosomal intergenic spacer analysis (ARISA) community profiling, and 16S rRNA gene sequencing approaches were used to study bacterial communities inhabiting submerged Lake Huron sinkholes inundated with hypoxic, sulfate-rich groundwater. Photosynthetic cyanobacterial mats on the sediment surface were dominated by Phormidium autumnale, while deeper, organically rich sediments contained diverse and active bacterial communities. PMID:19880643

  9. Effects of submerged and anaerobic fermentations on cassava flour ...

    African Journals Online (AJOL)

    Oke Oluwatoyin Victoria

    2015-03-18

    Mar 18, 2015 ... Cassava tubers for processing into cassava flour, Lafun a Nigerian locally fermented product was subjected to two different types of fermentations: submerged and anaerobic fermentation for 72 h. Physicochemical changes that occurred during fermentation and their influence on the functional, rheological ...

  10. Reactive oxygen species mediate growth and death in submerged plants

    Directory of Open Access Journals (Sweden)

    Bianka eSteffens

    2013-06-01

    Full Text Available Aquatic and semi-aquatic plants are well adapted to survive partial or complete submergence which is commonly accompanied by oxygen deprivation. The gaseous hormone ethylene controls a number of adaptive responses to submergence including adventitious root growth and aerenchyma formation. Reactive oxygen species (ROS act as signaling intermediates in ethylene-controlled submergence adaptation and possibly also independent of ethylene. ROS levels are controlled by synthesis, enzymatic metabolism and nonenzymatic scavenging. While the actors are by and large known, we still have to learn about altered ROS at the subcellular level and how they are brought about, and the signaling cascades that trigger a specific response. This review briefly summarizes our knowledge on the contribution of ROS to submergence adaptation and describes spectrophotometrical, histochemical and live cell imaging detection methods that have been used to study changes in ROS abundance. Electron paramagnetic resonance (EPR spectroscopy is introduced as a method that allows identification and quantification of specific ROS in cell compartments. The use of advanced technologies such as EPR spectroscopy will be necessary to untangle the intricate and partially interwoven signaling networks of ethylene and ROS.

  11. Effects of prolonged elevated water salinity on submerged ...

    African Journals Online (AJOL)

    environmental change, global warming. * To whom all correspondence should be addressed. e-mail: ian.russell@sanparks.org. Received 9 March 2017; accepted in revised form 10 October 2017. INTRODUCTION. Estuarine submerged macrophyte communities can be highly variable at both spatial and temporal scales, ...

  12. Protein enrichment of cassava peel by submerged fermentation ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-11

    Jan 11, 2010 ... Key words: Cassava peel, Trichoderma viride, enzyme, submerged fermentation, protein, amino acids. INTRODUCTION. Protein-energy malnutrition remains a major public health problem in many developing countries and there is the need to increase daily intake of protein, especially animal protein, using ...

  13. Relationships between the biomass of waterfowl and submerged ...

    African Journals Online (AJOL)

    The Wilderness Lakes system, comprising three estuarine lakes (Eilandvlei, Langvlei and Rondevlei), supports a diverse waterbird community, which includes 12 duck species and the abundant Red-knobbed Coot Fulica cristata. Biannual counts of waterfowl (ducks and Red-knobbed Coot) and assessments of submerged ...

  14. Protein enrichment of cassava peel by submerged fermentation with ...

    African Journals Online (AJOL)

    Protein enrichment of cassava peel by submerged fermentation with Trichoderma viride (ATCC 36316). OO Ezekiel, OC Aworh, HP Blaschek, TC Ezeji. Abstract. Cassava (Manihot esculenta Crantz) peel is one of the solid wastes produced as a consequence of cassava processing. It is low in protein but contains a large ...

  15. Nitrification in a submerged attached growth bioreactor using Luffa ...

    African Journals Online (AJOL)

    A laboratory-scale submerged attached growth bioreactor using Luffa cylindrica as support material for the immobilization of nitrifying bacteria was applied for polishing the effluent of an UASB reactor treating domestic wastewater under the tropical conditions of northeast Brazil, in the City of Campina Grande (7o 13' 11” ...

  16. Effects of submerged vegetation on water clarity across climates

    NARCIS (Netherlands)

    Kosten, S.; Lacerot, G.; Jeppesen, E.; Motta Marques, D.M.L.; Nes, van E.H.; Mazzeo, N.; Scheffer, M.

    2009-01-01

    A positive feedback between submerged vegetation and water clarity forms the backbone of the alternative state theory in shallow lakes. The water clearing effect of aquatic vegetation may be caused by different physical, chemical, and biological mechanisms and has been studied mainly in temperate

  17. Jet Calibration at ATLAS

    CERN Document Server

    Camacho, R; The ATLAS collaboration

    2011-01-01

    The accurate measurement of jets at high transverse momentum produced in proton proton collision at a centre of mass energy at \\sqrt(s)=7 TeV is important in many physics analysis at LHC. Due to the non-compensating nature of the ATLAS calorimeter, signal losses due to noise thresholds and in dead material the jet energy needs to be calibrated. Presently, the ATLAS experiment derives the jet calibration from Monte Carlo simulation using a simple correction that relates the true and the reconstructed jet energy. The jet energy scale and its uncertainty are derived from in-situ measurements and variation in the Monte Carlo simulation. Other calibration schemes have been also developed, they use hadronic cell calibrations or the topology of the jet constituents to reduce hadronic fluctuations in the jet response, improving in that way the jet resolution. The performances of the various calibration schemes using data and simulation, the evaluation of the modelling of the properties used to derive each calibration...

  18. Jet physics in ATLAS

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Measurements of hadronic jets provide tests of strong interactions which are interesting both in their own right and as backgrounds to many New Physics searches. It is also through tests of Quantum Chromodynamics that new physics may be discovered. The extensive dataset recorded with the ATLAS detector throughout the 7 TeV centre-of-mass LHC operation period allows QCD to be probed at distances never reached before. We present a review of selected ATLAS jet performance and physics measurements, together with results from new physics searches using the 2011 dataset. They include studies of the underlying event and fragmentation models, measurements of the inclusive jet, dijet and multijet cross sections, parton density functions, heavy flavours, jet shape, mass and substructure. Searches for new physics in monojet, dijet and photon-jet final states are also presented.

  19. Jet propulsion without inertia

    CERN Document Server

    Spagnolie, Saverio E

    2010-01-01

    A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies, and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented, and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e. jetting) surfaces are considered, and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increas...

  20. Quasar Jet Acceleration

    Science.gov (United States)

    Polito, Nicholas; Hough, David

    2009-10-01

    We observed radio jets in six lobe-dominated quasars (LDQs) from 1995 to 2008 using the NRAO VLBA at 8.4 and 15 GHz. These observations have tracked jet component positions and velocities over that time period. There is a correlation between apparent jet speed and projected core distance in these LDQs at greater than 99 per cent confidence levels (Hough 2008, Extragalactic Jets, eds: Rector and DeYoung, ASP, p. 274). Four of our sources show this effect particularly strongly. We only tracked single jet components over relatively short distances, but the assumption of a unique velocity profile allows us to study component motion on an effective timescale of approximately 20-50 years. Results for 3C207 and 3C263 show a good fit using a constant acceleration model. The cause of such acceleration is still unknown, though ``magnetic acceleration'' by a gradient in magnetic field pressure is one possibility.

  1. Study on the Effect of Jet Velocity on Mixing Performance and Sludge Prevention in Large-Scale Crude-Oil Tanks by the CFD Technique

    OpenAIRE

    Ali Akbar Lotfi Neyestanak; Mohammad Reza Tarybakhsh; Saeed Daneshmand

    2017-01-01

    In this paper, computational fluid dynamic modelling was developed to study the effect of the floating jet velocity or submerged rotary jet in sludge prevention in a large crude-oil storage tank. The Euler-Euler method was used in a two-dimensional CFD model to describe oil and sludge flow behaviour at the bottom of the storage tank. By modifying some parameters, the k-e model was used to describe the turbulence of the mixing flow. The results show the effect of jet velocity, angle, and time ...

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

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2013-01-01

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

  3. Simulations of Solar Jets

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    Formation of a coronal jet from twisted field lines that have reconnected with the ambient field. The colors show the radial velocity of the plasma. [Adapted from Szente et al. 2017]How do jets emitted from the Suns surface contribute to its corona and to the solar wind? In a recent study, a team of scientists performed complex three-dimensional simulations of coronal jets to answer these questions.Small ExplosionsCoronal jets are relatively small eruptions from the Suns surface, with heights of roughly 100 to 10,000 km, speeds of 10 to 1,000 km/s, and lifetimes of a few minutes to around ten hours. These jets are constantly present theyre emitted even from the quiet Sun, when activity is otherwise low and weve observed them with a fleet of Sun-watching space telescopes spanning the visible, extreme ultraviolet (EUV), and X-ray wavelength bands.A comparison of simulated observations based on the authors model (left panels) to actual EUV and X-ray observations of jets (right panels). [Szente et al. 2017]Due to their ubiquity, we speculate that these jets might contribute to heating the global solar corona (which is significantly hotter than the surface below it, a curiosity known as the coronal heating problem). We can also wonder what role these jets might play in driving the overall solar wind.Launching a JetLed by Judit Szente (University of Michigan), a team of scientists has explored the impact of coronal jets on the global corona and solar wind with a series of numerical simulations. Szente and collaborators used three-dimensional, magnetohydrodynamic simulations that provide realistic treatment of the solar atmosphere, the solar wind acceleration, and the complexities of heat transfer throughout the corona.In the authors simulations, a jet is initiated as a magnetic dipole rotates at the solar surface, winding up field lines. Magnetic reconnection between the twisted lines and the background field then launches the jet from the dense and hot solar

  4. Applying the seedling-emergence method under waterlogged conditions to detect the seed bank of aquatic plants in submerged sediments

    NARCIS (Netherlands)

    Boedeltje, G; ter Heerdt, GNJ; Bakker, JP

    Seed bank studies focused on submerged aquatic plants are generally performed under submerged conditions, using the seedling-emergence method. However, if a study targets at both submerged species and helophytes, submerged conditions are generally not suitable. We tested the emergence of seedlings

  5. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  6. Jet noise suppression by swirling the jet flow.

    Science.gov (United States)

    Schwartz, I. R.

    1973-01-01

    The effect of swirling flow on jet noise suppression was experimentally investigated in a relatively small, low-thrust, fan-jet engine. Measurements of acoustic properties of the near and far fields, jet-flow characteristics, and engine thrust were made with and without stationary swirl vanes installed in the primary exhaust nozzle. Preliminary test results indicate that substantial reductions in jet overall sound pressure levels and overall acoustic power were obtained with minimal thrust losses. Based on preliminary analysis, present results, and previous experiments with swirling hot jets, it is predicted that even greater jet noise reductions can be obtained in higher thrust engines, particularly with afterburning, by swirling jet exhaust.

  7. Jets and QCD

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kramer, G. [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

    2010-12-15

    The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review we summarise the properties of quark and gluon jets and the impact of their observation on Quantum Chromodynamics, primarily the discovery of the gluons as the carriers of the strong force. Focusing on these basic points, jets in e{sup +}e{sup -} collisions will be in the foreground of the discussion. In addition we will delineate the role of jets as tools for exploring other particle aspects in ep and pp/p anti p collisions - quark and gluon densities in protons, measurements of the QCD coupling, fundamental 2-2 quark/gluon scattering processes, but also the impact of jet decays of top quarks, and W{sup {+-}},Z bosons on the electroweak sector. The presentation to a large extent is formulated in a non-technical language with the intent to recall the significant steps historically and convey the significance of this field also to communities beyond high energy physics. (orig.)

  8. Comparison of burnout characteristics in jet impingement cooling and stray cooling

    Science.gov (United States)

    Cho, C. S. K.; Wu, K.

    Characteristics of spray cooling and jet impingement methods were investigated. The jet impingement cooling method created a large dry area on the test surface when the burnout heat flux was approached. In the spray cooling method, a liquid film with nucleate boiling was maintained for the entire experiment until a burnout was occurred. The spray cooling method produced a higher burnout heat flux than the jet impingement cooling method for the same liquid flow rate. In the spray cooling method, sprayed droplet velocity was a parameter for determining the burnout heat flux. The burnout heat flux in jet impingement cooling also showed dependency on the liquid jet velocity. Results of two methods for cooling the surface area were compared and correlated with the Weber number.

  9. Optimized Parameters for a Mercury Jet Target

    Energy Technology Data Exchange (ETDEWEB)

    Ding, X.; Kirk, H.

    2010-12-01

    A study of target parameters for a high-power, liquid mercury jet target system for a neutrino factory or muon collider is presented. Using the MARS code, we simulate particle production initiated by incoming protons with kinetic energies between 2 and 100 GeV. For each proton beam energy, we maximize production by varying the geometric parameters of the target: the mercury jet radius, the incoming proton beam angle, and the crossing angle between the mercury jet and the proton beam. The number of muons surviving through an ionization cooling channel is determined as a function of the proton beam energy. We optimize the mercury jet target parameters: the mercury jet radius, the incoming proton beam angle and the crossing angle between the mercury jet and the proton beam for each proton beam energy. The optimized target radius varies from about 0.4 cm to 0.6 cm as the proton beam energy increases. The optimized beam angle varies from 75 mrad to 120 mrad. The optimized crossing angle is near 20 mrad for energies above 5 GeV. These values differ from earlier choices of 67 mrad for the beam angle and 33 mrad for the crossing angle. These new choices for the beam parameters increase the meson production by about 20% compared to the earlier parameters. Our study demonstrates that the maximum meson production efficiency per unit proton beam power occurs when the proton kinetic energy is in the range of 5-15 GeV. Finally, the dependence on energy of the number of muons at the end of the cooling channel is nearly identical to the dependence on energy of the meson production 50 m from the target. This demonstrates that the target parameters can be optimized without the additional step of running the distribution through a code such as ICOOL that simulates the bunching, phase rotation, and cooling.

  10. Methods for geothermal reservoir detection emphasizing submerged environments

    Energy Technology Data Exchange (ETDEWEB)

    Case, C.W.; Wilde, P.

    1976-05-21

    This report has been prepared for the California State Lands Commission to aid them in evaluating exploration programs for geothermal reservoirs, particularly in submerged land environments. Three charts show: (1) a logical progression of specific geologic, geochemical, and geophysical exploration techniques for detecting geothermal reservoirs in various geologic environments with emphasis on submerged lands, (2) various exploration techniques which can be used to develop specific information in geothermal areas, and (3) if various techniques will apply to geothermal exploration according to a detailed geologic classification. A narrative in semi-outline form supplements these charts, providing for each technique; a brief description, advantages, disadvantages, special geologic considerations, and specific references. The specific geologic situation will control the exploration criterion to be used for reservoir detection. General guidelines are established which may be of use in evaluating such a program, but the optimum approach will vary with each situation.

  11. Antitumor activity of submerged biomass of Hericium erinaceus

    OpenAIRE

    Avtonomova, A.; Bakanov, A.; Vinokurov, V.; Bukhman, V.; Krasnopolskaya, L.

    2011-01-01

    Submerged cultivation of Hericium erinaceus in various media has been studied. The yield of biomass was shown to depend mainly on the carbon source, whereas the content of watersoluble polysaccharides depended primarily on the nitrogen source. Using optimal medium composition, the biomass yield of 22-23 g/l in 7 days was achieved. The antitumor activity was studied in vivo with using 2 tumor strains. The inhibition ratio of tumor in these experience reached 86%. An exposure of mice with tumor...

  12. Submerged beachrock preservation in the context of wave ravinement

    Science.gov (United States)

    Pretorius, Lauren; Green, Andrew N.; Andrew Cooper, J.

    2018-02-01

    This study examines a Holocene-aged submerged shoreline, Limestone Reef, located in the shallow subtidal zone of South Africa's east coast. It comprises an elongate, coast-oblique, slab-like outcrop of beachrock situated above the contemporary fair-weather wave base. It is currently undergoing mechanical disintegration. Its unique and rare preservation in a high-energy setting affords an opportunity to examine the mechanical processes occurring during wave ravinement associated with rising sea level. The submerged shoreline and the adjacent shoreface were examined using high-resolution seismic reflection, side-scan sonar and shallow-water multibeam echosounding techniques. Limestone Reef rests on top of unconsolidated Holocene deposits. The structure's surface is characterised by reef-perpendicular gullies with rubble derived from the slab fringing its seaward edge. Limestone Reef slopes gently seawards and has a steep landward-facing edge where gullies are most prominently developed. Teardrop-shaped rippled scour depressions, marked by high backscatter, are located seawards of the submerged shoreline. These elongate in a seaward direction and are filled with bioclastic gravels and residual rubble from Limestone Reef. The gullies in the upstanding structure are indicative of wave plucking and abrasion of the shoreline. The material exposed by the rippled scour depressions is identical to that comprising the postglacial ravinement surface identified in the offshore stratigraphy. These deposits are considered to represent the contemporary, actively forming wave ravinement surface. The results suggest that wave ravinement of submerged shorelines is a discontinuous process dominated by the seaward entrainment of material from its landward edge controlled by high-energy drawback during storm surges. The ravinement process appears to operate at the seasonal scale and averages out over the long-term millennial scale for the continuous surface.

  13. Submerged Pagodas of Mahabalipuram - Study based on underwater investigations

    Digital Repository Service at National Institute of Oceanography (India)

    Sundaresh; Gaur, A.S.; Tripati, S.; Vora, K.H.; Rao, K.M.

    - gested that this place could have served as an ancient port (Dayalan, 1992). Mahabalipuram was well known to earlier mariners as 'Seven Pagodas' since the 1 7h century AD. it is generally believed that out of 7 temples originally con- structed, all... based on the local traditions and available literature. The local tradition and the people of Mahabalipuram believe that five temples similar to the Shore Temple have been submerged in the sea. On the basis of local traditions Ancient Tamil...

  14. Instrumentation, control, and automation for submerged anaerobic membrane bioreactors

    OpenAIRE

    Robles Martínez, Ángel; Durán Pinzón, Freddy; Ruano García, María Victoria; Ribes Bertomeu, José; Rosado Muñoz, Alfredo; SECO TORRECILLAS, AURORA; Ferrer, J.

    2015-01-01

    A submerged anaerobic membrane bioreactor (AnMBR) demonstration plant with two commercial hollow-fibre ultrafiltration systems (PURON® , Koch Membrane Systems, PUR-PSH31) was designed and operated for urban wastewater treatment. An instrumentation, control, and automation (ICA) system was designed and implemented for proper process performance. Several single-input-single-output (SISO) feedback control loops based on conventional on off and PID algorithms were implemented to control the follo...

  15. Diversification of gene expression during formation of static submerged biofilms by Escherichia coli

    Directory of Open Access Journals (Sweden)

    Olga Besharova

    2016-10-01

    Full Text Available Many bacteria primarily exist in nature as structured multicellular communities, so called biofilms. Biofilm formation is a highly regulated process that includes the transition from the motile planktonic to sessile biofilm lifestyle. Cellular differentiation within a biofilm is a commonly accepted concept but it remains largely unclear when, where and how exactly such differentiation arises. Here we used fluorescent transcriptional reporters to quantitatively analyze spatio-temporal expression patterns of several groups of genes during the formation of submerged Escherichia coli biofilms in an open static system. We first confirm that formation of such submerged biofilms as well as pellicles at the liquid-air interface requires the major matrix component, curli, and flagella-mediated motility. We further demonstrate that in this system, diversification of gene expression leads to emergence of at least three distinct subpopulations of E. coli, which differ in their levels of curli and flagella expression, and in the activity of the stationary phase sigma factor σS. Our study reveals mutually exclusive expression of curli fibers and flagella at the single cell level, with high curli levels being confined to dense cell aggregates/microcolonies and flagella expression showing an opposite expression pattern. Interestingly, despite the known σS-dependence of curli induction, there was only a partial correlation between the σS activity and curli expression, with subpopulations of cells having high σS activity but low curli expression and vice versa. Finally, consistent with different physiology of the observed subpopulations, we show striking differences between the growth rates of cells within and outside of aggregates.

  16. Ink jet technology for large area organic light-emitting diode and organic photovoltaic applications

    NARCIS (Netherlands)

    Ren, M.; Gorter, H.; Michels, J.; Andriessen, R.

    2011-01-01

    Due to its flexibility and ease of patterning, ink jet printing has become a popular technique for the noncontact deposition of liquids, solutions, and melts on a variety of substrates at lateral resolutions down to 10 μm. This article presents a study of ink jet printing of homogeneous layers of

  17. Intermonsoonal equatorial jets

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.

    , respectively. Hydrographic features and transport computations favour a well developed equatorial jet during both seasons. The net surface eastward and subsurface westward flows are well balanced during the premonsoon transition period and appear...

  18. Jet Measurements In CMS

    CERN Document Server

    Ganguly, Sanmay

    2013-01-01

    A measurement of inclusive jet and dijet production cross sections is presented. Data from large hadron collider (LHC) proton-proton collisions at $\\sqrt{s}=$ 7 TeV, corresponding to $4.67 fb^{-1}$ of integrated luminosity, have been collected with the compact muon solenoid (CMS) detector. Jets are reconstructed with the anti-$k_T$ clustering algorithm with size parameter $R=0.7$, extending to rapidity $|y|=2.5$, transverse momentum $p_{T}=$ 2 TeV, and dijet invariant mass $M_{JJ}=$ 5 TeV. The measured cross sections are corrected for detector effects and compared to perturbative QCD predictions at next-to-leading order (NLO), corrected for non perturbative (NP) factors, using various sets of parton distribution functions. Determination Of Jet Energy Correction from $\\sqrt{s}=$ 7 TeV CMS data is presented. The individual components are determined. The jet energy scale uncertainty factors are also shown.

  19. Research efforts for detection and recovery of submerged oil

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, K. [United States Coast Guard, Groton, CT (United States). Research and Development Center

    2009-07-01

    Submerged oil can sink and destroy shellfish and other marine populations in addition to causing closure of water intakes at industrial facilities and power plants. However, current methods to find and recover oil from spills involving submerged oil are inadequate. The underwater environment presents major challenges such as poor visibility, difficulty in tracking oil spill movement, colder temperatures, inadequate containment methods and problems with the equipment's interaction with water. This paper reported on a multi-year project launched by the Research and Development Center of the United States Coast Guard to develop a complete approach for spills of submerged oil. The project involved detection technologies and recovery methods for oil on the bottom of any body of water. Proof of concept (POC) and prototype tests of potential detection technologies were evaluated during tests at the Ohmsett facility in Leonardo, New Jersey. The technologies included sonar, laser fluorometry, real-time mass spectrometry and in-situ fluorometry. This paper described the development of a complete specification for an integrated recovery system along with a plan for future development. 9 refs., 2 tabs., 11 figs.

  20. Production of Alpha Amylase by Bacillus cereus in Submerged Fermentation

    Directory of Open Access Journals (Sweden)

    Helen H. Raplong

    2014-09-01

    Full Text Available Microorganisms have the ability to secrete enzymes when they are grown in the presence of certain substrates. Amylases are among the most important industrial enzymes and are of great significance in biotechnological studies. Bacteria belonging to the genus Bacillus were isolated using mannitol egg yolk polymyxin B (MYP agar a highly selective media for Bacillus cereus isolation. The isolates were tested for α-amylase production on nutrient agar supplemented with starch and in submerged fermentation. The bacteria isolated and identified (using the Microgen Bacillus identification kit were all Bacillus cereus and SB2 had the largest zone of hydrolysis of 12mm on nutrient agar supplemented with starch as well as the highest enzyme activity of 1.62U/ml. Amylase activity of 2.56U/ml was obtained after 24 hours incubation in submerged fermentation. When amylase enzyme production parameters where optimized, maximum amylase activity was obtained at a pH of 6.5, temperature of 350C, incubation time of 24 hours and 4% inoculums concentration. Bacillus cereus SB2 is a potential isolate for alpha-amylase production with soluble starch as the sole carbon source in submerged fermentation.

  1. Protostellar Jets in Context

    CERN Document Server

    Tsinganos, Kanaris; Stute, Matthias

    2009-01-01

    This volume contains the proceedings of the Conference Protostellar Jets in Context held by the JETSET Marie Curie Research Training Network in July 2008. This meeting not only served to showcase some of the network's achievements but was also a platform to hear from, discuss and debate the recent findings of world-class astrophysicists in the field of protostellar jet research. Jets from young stars are of course not an isolated astrophysical phenomenon. It is known that objects as diverse as young brown dwarfs, planetary nebulae, symbiotic stars, micro-quasars, AGN, and gamma-ray bursters produce jets. Thus in a series of talks, protostellar jets were put in context by comparing them with their often much larger brethren and also by considering the ubiquitous accretion disks that seem to be necessary for their formation. With this spectrum of contributions on observations and the theory of astrophysical jets and accretion disks, this book serves as a comprehensive reference work for researchers and students...

  2. Studies towards the stabilisation of a mushroom phytase produced by submerged cultivation.

    Science.gov (United States)

    Spier, Michele Rigon; Behsnilian, Diana; Zielinski, Acácio; Konietzny, Ursula; Greiner, Ralf

    2015-10-01

    A novel phytase from Ganoderma australe G24 was produced by submerged cultivation and recovery. Liquid and solid forms of phytase were developed; both types of product were formulated using different additives. Ganoderma australe G24 phytase was very stable in liquid form with NaCl and sodium acetate buffer. Solid form products were obtained by spray-drying using different polymers to encapsulate the phytase and the capsules obtained were analyzed by electron microscopy. Micrographs confirmed micro and nanoparticles formed with maltodextrin (300 nm to 7-8 µm) without the presence of agglomerates. The use of maltodextrin for solid formulation of G. australe G24 phytase is recommended, and resulted in good stability after the drying process and during storage (shelf life). Kinetic models of phytase inactivation in the microencapsulated powders over time were proposed for the different stabilizing additives. Inactivation rate constants, half-lives and D values (decimal reduction time) were obtained. Phytase encapsulated with maltodextrin remained stable after 90 days, with k 0.0019 day(-1) and a half-life (t1/2) of 367.91 days(-1).

  3. Temporal instability analysis of inviscid compound jets falling under gravity

    Science.gov (United States)

    Mohsin, Muhammad; Uddin, Jamal; Decent, Stephen P.; Afzaal, Muhammad F.

    2013-01-01

    Compound liquid jets can be used in a variety of industrial applications ranging from capsule production in pharmaceutics to enhance printing methods in ink-jet printing. An appreciation of how instability along compound jets can lead to breakup and droplet formation is thus critical in many fields in science and engineering. In this paper, we perform a theoretical analysis to examine the instability of an axisymmetric inviscid compound liquid jet which falls vertically under the influence of gravity. We use a long-wavelength, slender-jet asymptotic expansion to reduce the governing equations of the problem into a set of one-dimensional partial differential equations, which describe the evolution of the leading-order axial velocity of the jet as well as the radii of both the inner and the outer interfaces. We first determine the steady-state solutions of the one-dimensional model equations and then we perform a linear temporal instability analysis to obtain a dispersion relation, which gives us useful information about the maximum growth rate and the maximum wavenumber of the imposed wave-like disturbance. We use our results to estimate the location and qualitative nature of breakup and then compare our results with numerical simulations.

  4. The theoretical model for the annular jet instability - Revisited

    Science.gov (United States)

    Lee, C. P.; Wang, T. G.

    1989-01-01

    The theoretical model of Lee and Wang (1986) for the instability of an annular jet, in which the jet's liquid layer is treated as a thin liquid sheet, is examined. It is suggested that the model should be altered so that when the envelope is closing its bottleneck during collapse, the new envelope experiences a sharp pressure pulse from its gaseous core, reversing the normal velocity of the sheet enough to maintain continuous constant gas flow. Using this improved version of the model, it is shown that if the liquid velocity is high enough and the gas velocity is greater than the liquid velocity, the bubble-formation frequency varies linearly with the difference between the two velocities, but not with their individual values.

  5. Prevention of tissue damage by water jet during cavitation

    Science.gov (United States)

    Palanker, Daniel; Vankov, Alexander; Miller, Jason; Friedman, Menahem; Strauss, Moshe

    2003-08-01

    Cavitation bubbles accompany explosive vaporization of water following pulsed energy deposition in liquid media. Bubbles collapsing at the tip of a surgical endoprobe produce a powerful and damaging water jet propagating forward in the axial direction of the probe. We studied interaction of such jet with tissue using fast flash photography and modeled the flow dynamics using a two-dimensional Rayleigh-type hydrodynamic simulation. Maximal velocity of the jet generated at pulse energies of up to 1 mJ was about 80 m/s. The jet can produce tissue damage at a distance exceeding the radius of the cavitation bubble by a factor of 4. We demonstrate that formation of this flow and associated tissue damage can be prevented by application of the concave endoprobes that slow down the propagation of the back boundary of the bubble. Similar effect can be achieved by positioning an obstacle to the flow, such as a ring behind the tip.

  6. Investigation of the concave curvature effect for an impinging jet flow

    Science.gov (United States)

    Aillaud, P.; Gicquel, L. Y. M.; Duchaine, F.

    2017-11-01

    The concave curvature effect for an impinging jet flow is discussed in this paper. To do so, a submerged axisymmetric isothermal impinging jet at a Reynolds number (based on the nozzle diameter and the bulk velocity at the nozzle outlet) Re=23 000 and for a nozzle to plate distance of two jet diameters H =2 D is considered. This investigation is done numerically using a wall-resolved large-eddy simulation. Two geometrical arrangements are studied. These correspond to a jet impinging on a flat plate and a jet impinging on a hemispherical concave plate with a relative curvature D /d =0.089 , where d is the concave plate diameter. A detailed comparison shows that both flow configurations are very similar in terms of flow dynamics and heat transfer behaviors. The same mechanisms, coming from the initial jet instability and driving the heat transfer at the wall, are found for both geometries. However, a reduction of the mean wall heat transfer is reported for the jet impinging on the concave surface when compared to the flat plate impingement. This reduction mainly comes from the alleviation of the secondary peak. The deterioration of wall heat transfer is shown to be caused by a reduction in the intensity of the intermittent cold fluid injections generated by the secondary structures. These weaker events are assumed to be the consequence of the stabilizing normal pressure gradient, in the outer layer of the wall jet, induced by the concave curvature of the plate. This result goes against the current consensus, inherited from boundary layer studies, that is to say, that concave curvature enhances the heat transfer rate at the wall due to the formation of Görtler vortices. In an attempt to explain the contradictory result of the present study, a discussion is proposed in this paper showing that the commonly used analogy with boundary layer results must be made with care owing to several inherent differences between impinging jet and boundary layer flows.

  7. Molecular Beam Studies of Volatile Liquids and Fuel Surrogates Using Liquid Microjets

    Science.gov (United States)

    2014-12-18

    wide range of high-vapor pressure liquids, including octane, isooctane, dodecane, squalane , methylnaphthalene, ethylene glycol, and Jet A and JP-8 fuels...the experiments reported here, we directed Ne atoms and O2 molecules at liquid microjets of pure dodecane (C12H26) and pure squalane (C30H62), in...O2 molecules is transferred to liquid dodecane and squalane , with little difference between the short and long-chain liquids. These results imply

  8. Antioxidant Properties of the Edible Basidiomycete Armillaria mellea in Submerged Cultures

    OpenAIRE

    Lung, Ming-Yeou; Chang, Yu-Cheng

    2011-01-01

    Antioxidant components, ascorbic acid, total flavonoids and total phenols are produced effectively by Armillaria mellea submerged cultures. Dried mycelia and mycelia-free broths obtained by A. mellea submerged cultures are extracted with methanol and hot water and investigated for antioxidant properties. Methanolic extracts from dried mycelia (MEM) and mycelia-free broth (MEB) and hot water extracts from dried mycelia (HWEM) by A. mellea submerged cultures show good antioxidant properties as ...

  9. Enhanced effects of biotic interactions on predicting multispecies spatial distribution of submerged macrophytes after eutrophication

    OpenAIRE

    Song, Kun; Cui, Yichong; Zhang, Xijin; Pan, Yingji; Xu, Junli; Xu, Kaiqin; Da, Liangjun

    2017-01-01

    Abstract Water eutrophication creates unfavorable environmental conditions for submerged macrophytes. In these situations, biotic interactions may be particularly important for explaining and predicting the submerged macrophytes occurrence. Here, we evaluate the roles of biotic interactions in predicting spatial occurrence of submerged macrophytes in 1959 and 2009 for Dianshan Lake in eastern China, which became eutrophic since the 1980s. For the four common species occurred in 1959 and 2009,...

  10. Two-valued breakup length of a water jet issuing from a finite-length nozzle under normal gravity.

    Science.gov (United States)

    Umemura, Akira; Kawanabe, Sho; Suzuki, Sousuke; Osaka, Jun

    2011-09-01

    Laboratory experiments are conducted in which water is issued vertically downward from a finite-length nozzle at a constant speed using a piston. The results of these experiments indicate that the breakup length of the liquid jet is two-valued at Weber numbers greater than unity but less than a certain value, which depends on the nozzle length-to-radius ratio and the Bond number. In addition to a long breakup length, which is consistent with the conventional observation, another shorter breakup length is realized at the same jet issue speed. Each experimental run for a specific jet issue speed begins from the start of liquid issue so that each run is independent of the other runs. Transition between the two breakup lengths seldom occurs in each run. Which of the two breakup lengths occurs is determined at the start of liquid issue, when the capillary wave produced by the liquid jet tip contraction easily reaches the nozzle exit. Unlike the conventional belief, which is based on the Plateau-Rayleigh instability theory, this experimental evidence demonstrates that liquid jet disintegration occurs in a deterministic manner. The previously proposed self-destabilizing mechanism of a liquid jet in microgravity, in which the origin of the unstable wave responsible for the breakups is attributed to the formation of an upstream propagating capillary wave at every breakup, is extended to explore the physics underlying the observed liquid jet disintegration behaviors.

  11. GigaUnit Transplant System: A New Mechanical Tool for Transplanting Submerged Aquatic Vegetation

    National Research Council Canada - National Science Library

    Shafer, Deborah J

    2008-01-01

    Submerged aquatic vegetation (SAV) performs many important ecosystem functions, including wave attenuation and sediment stabilization, water quality improvement, primary production, food web support for secondary consumers...

  12. B-jets and z + b-jets at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Jeans, Daniel; /Rome U.

    2006-06-01

    The authors present CDF cross-section measurements for the inclusive production of b jets and the production of b jets in association with a Z{sup 0} boson. Both measurements are in reasonable agreement with NLO QCD predictions.

  13. Cryogenic Impinging Jets Subjected to High Frequency Transverse Acoustic Forcing in a High Pressure Environment

    Science.gov (United States)

    2016-07-27

    experimental data,” Journal of Fluid Mechanics, Vol. 656, 2010, pp. 5-28 15Harrje D. T., and Reardon, F. H., “ Liquid Propellant Rocket Combustion ...for liquid propellant atomization in rocket engines1- 2. Liquid rocket engines like the F-1 have successfully used like-on-like impinging jet...Atomization,” Liquid Rocket Combustion Instability, edited by V. Yang and W. E. Anderson, Progress in Astronautics and Aeronautics, vol. 169, AIAA

  14. In-liquid plasma devices and methods of use thereof

    KAUST Repository

    Cha, Min Suk

    2017-08-10

    Devices and methods for generating a plasma in a liquid are provided. A low- dielectric material can be placed in contact with the liquid to form an interface a distance from an anode. A voltage can be applied across the anode and a cathode submerged in the liquid to produce the plasma. A variety of devices are provided, including for continuous operation. The devices and methods can be used to generate a plasma in a variety of liquids, for example for water treatment, hydrocarbon reformation, or synthesis of nanomaterial.

  15. Multiple Jets at the LHC with High Energy Jets

    DEFF Research Database (Denmark)

    Andersen, Jeppe Rosenkrantz; Smillie, Jennifer M.

    2011-01-01

    We present a flexible Monte Carlo implementation of the perturbative framework of High Energy Jets, describing multi-jet events at hadron colliders. The description includes a resummation which ensures leading logarithmic accuracy for large invariant mass between jets, and is matched to tree...... of the perturbative corrections on several dijet and trijet observables which are relevant in the search for new physics....

  16. Restoring Ecological Function to a Submerged Salt Marsh

    Science.gov (United States)

    Stagg, C.L.; Mendelssohn, I.A.

    2010-01-01

    Impacts of global climate change, such as sea level rise and severe drought, have altered the hydrology of coastal salt marshes resulting in submergence and subsequent degradation of ecosystem function. A potential method of rehabilitating these systems is the addition of sediment-slurries to increase marsh surface elevation, thus ameliorating effects of excessive inundation. Although this technique is growing in popularity, the restoration of ecological function after sediment addition has received little attention. To determine if sediment subsidized salt marshes are functionally equivalent to natural marshes, we examined above- and belowground primary production in replicated restored marshes receiving four levels of sediment addition (29-42 cm North American Vertical Datum of 1988 [NAVD 88]) and in degraded and natural ambient marshes (4-22 cm NAVD 88). Moderate intensities of sediment-slurry addition, resulting in elevations at the mid to high intertidal zone (29-36 cm NAVD 88), restored ecological function to degraded salt marshes. Sediment additions significantly decreased flood duration and frequency and increased bulk density, resulting in greater soil drainage and redox potential and significantly lower phytotoxic sulfide concentrations. However, ecological function in the restored salt marsh showed a sediment addition threshold that was characterized by a decline in primary productivity in areas of excessive sediment addition and high elevation (>36 cm NAVD 88). Hence, the addition of intermediate levels of sediment to submerging salt marshes increased marsh surface elevation, ameliorated impacts of prolonged inundation, and increased primary productivity. However, too much sediment resulted in diminished ecological function that was equivalent to the submerged or degraded system. ?? 2010 Society for Ecological Restoration International.

  17. Enhanced Sorbitol Production under Submerged Fermentation using Lactobacillus plantarum

    Directory of Open Access Journals (Sweden)

    Khan Nadiya Jan

    2017-04-01

    Full Text Available Background and Objective: Sorbitol is a non-toxic and slightly hygroscopic compound with different applications. Zymomonas mobiles produces sorbitol from sucrose or mixtures of glucose and fructose (formation is coupled with the dehydrogenation of glucose to glucono-δ- lactone. Recombinant Zymomonas mobilis may produce sorbitol and gluconic acid from glucose and fructose using different divalent metal ions with reduced the ethanol yield andsignificantly increased yield of sorbitol. Current study envisaged to alter the media components, physical process parameters and supplementation of amino acids for enhanced sorbitol production.Material and Methods: Several process variables were evaluated on sorbitol production including carbon sources (glucose, fructose, maltose, sucrose, carbon concentrations (5, 10, 20 and 25 g l-1, nitrogen sources (peptone, tryptone, yeast extract, beef extract and organic nitrogen mix, temperatures (25, 29, 33, 37, 41°C, pH (6, 6.5, 7 , 7.5 ,8, agitation rate (50, 100, 150, 200 rpm and amino acids (cysteine, cystine, tryptophanin batch cultivation ofLactobacillus plantarum NCIM 2912. Shake flask cultivation performed under optimum conditions like temperature 37°C, pH 7.0 and agitation rate of 150 rpm, resulted in enhanced sorbitol production. Comparative study of sorbitol production in solid state fermentation and submerged fermentation was also evaluated.Results and Conclusion: Batch cultivation under submerged conditions further performed in 7.5-l lab scale bioreactor (working volume 3.0-l under optimized conditions resulted in maximum cell biomass of 8.95±0.03 g g-1 and a sorbitol content of 9.78±0.04 g l-1 after 42.0 h of fermentation. Scale up study on bioreactor resulted in maximum sorbitol yield (Yp/x and productivity of 1.11 g g-1 and 0.50 g l-1 h under submerged fermentation, respectively.Conflict of interest: The authors declare no conflict of interest.

  18. Flow structure of conical distributed multiple gas jets injected into a water chamber

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jiajun; Yu, Yonggang [Nanjing University of Science and Technology, Nanjing (China)

    2017-04-15

    Based on an underwater gun firing project, a mock bullet with several holes on the head was designed and experimented to observe the combustion gas injected into a cylindrical water chamber through this mock bullet. The combustion gas jets contain one vertical central jet and 4 to 8 slant lateral jets. A high speed camera system was used to record the expansion of gas jets in the experimental study. In numerical simulations, the Euler two-fluid model and volume of fluid method were adopted to describe the gas-liquid flow. The results show the backflow zone in lateral jet is the main factor influencing the gas-liquid turbulent mixing in downstream. On cross sections, the gas volume fraction increased with time but the growth rate decreased. With a change of nozzle structure, the gas fraction was more affected than the shock structure.

  19. [Genetic algorithm for fermentation kinetics of submerged fermentation by Morchella].

    Science.gov (United States)

    Wang, Ying; Piao, Meizi; Sun, Yonghai

    2008-08-01

    Fermentation kinetics is important for optimizing control and up-scaling fermentation process. We studied submerged fermentation kinetics of Morchella. Applying the genetic Algorithm in the Matlab software platform, we compared suitability of the Monod and Logistic models, both are commonly used in process of fungal growth, to describe Morchella growth kinetics. Meanwhile, we evaluated parameters involved in the models for Morchella growth, EPS production and substrate consumption. The results indicated that Logistic model fit better with the experimental data. The average error of this model was 5.8%. This kinetics model can be useful for optimizing and up-scaling fungal fermentation process.

  20. Slag Metal Reactions during Submerged Arc Welding of Alloy Steels

    Science.gov (United States)

    Mitra, U.; Eagar, T. W.

    1984-01-01

    The transfer of Cr, Si, Mn, P, S, C, Ni, and Mo between the slag and the weld pool has been studied for submerged arc welds made with calcium silicate and manganese silicate fluxes. The results show a strong interaction between Cr and Si transfer but no interaction with Mn. The manganese silicate flux produces lower residual sulfur while the calcium silicate fluxes are more effective for removal of phosphorus. The effective oxygen reaction temperature lies between 1700 and 2000 °C for all elements studied. Evidence of Cr and Mn loss by metal vaporization is also presented.

  1. Resolving boosted jets with XCone

    Energy Technology Data Exchange (ETDEWEB)

    Thaler, Jesse; Wilkason, Thomas F. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA, 02139 (United States)

    2015-12-09

    We show how the recently proposed XCone jet algorithm http://dx.doi.org/10.1007/JHEP11(2015)072 smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies — dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs — that demonstrate the physics applications of XCone over a wide kinematic range.

  2. Jet Physics in ATLAS

    CERN Document Server

    Sandoval, C; The ATLAS collaboration

    2012-01-01

    Measurements of hadronic jets provide tests of strong interactions which are interesting both in their own right and as backgrounds to many New Physics searches. It is also through tests of Quantum Chromodynamics that new physics may be discovered. The extensive dataset recorded with the ATLAS detector throughout the 7 TeV centre-of-mass LHC operation period allows QCD to be probed at distances never reached before. We present a review of selected ATLAS jet physics measurements. These measurements constitute precision tests of QCD in a new energy regime, and show sensitivity to the parton densities in the proton and to the value of the strong coupling, alpha_s.

  3. Explosive fragmentation of liquids in spherical geometry

    Science.gov (United States)

    Milne, A.; Longbottom, A.; Frost, D. L.; Loiseau, J.; Goroshin, S.; Petel, O.

    2017-05-01

    Rapid acceleration of a spherical shell of liquid following central detonation of a high explosive causes the liquid to form fine jets that are similar in appearance to the particle jets that are formed during explosive dispersal of a packed layer of solid particles. Of particular interest is determining the dependence of the scale of the jet-like structures on the physical parameters of the system, including the fluid properties (e.g., density, viscosity, and surface tension) and the ratio of the mass of the liquid to that of the explosive. The present paper presents computational results from a multi-material hydrocode describing the dynamics of the explosive dispersal process. The computations are used to track the overall features of the early stages of dispersal of the liquid layer, including the wave dynamics, and motion of the spall and accretion layers. The results are compared with new experimental results of spherical charges surrounded by a variety of different fluids, including water, glycerol, ethanol, and vegetable oil, which together encompass a significant range of fluid properties. The results show that the number of jet structures is not sensitive to the fluid properties, but primarily dependent on the mass ratio. Above a certain mass ratio of liquid fill-to-explosive burster ( F / B), the number of jets is approximately constant and consistent with an empirical model based on the maximum thickness of the accretion layer. For small values of F / B, the number of liquid jets is reduced, in contrast with explosive powder dispersal, where small F / B yields a larger number of particle jets. A hypothetical explanation of these features based on the nucleation of cavitation is explored numerically.

  4. Analysis of the effect of impact of near-wall acoustic bubble collapse micro-jet on Al 1060.

    Science.gov (United States)

    Ye, Linzheng; Zhu, Xijing

    2017-05-01

    The bubble collapse near a wall will generate strong micro-jet in a liquid environment under ultrasonic field. To explore the effect of the impact of near-wall acoustic bubble collapse micro-jet on an aluminum 1060 sheet, the cavitation threshold formula and micro-jet velocity formula were first proposed. Then the Johnson-Cook rate correlation material constitutive model was considered, and a three-dimensional fluid-solid coupling model of micro-jet impact on a wall was established and analyzed. Finally, to validate the model, ultrasonic cavitation test and inversion analysis based on the theory of spherical indentation test were conducted. The results show that cavitation occurs significantly in the liquid under ultrasonic field, as the applied ultrasonic pressure amplitude is much larger than liquid cavitation threshold. Micro pits appear on the material surface under the impact of micro-jet. Pit depth is determined by both micro-jet velocity and micro-jet diameter, and increases with their increase. Pit diameter is mainly related to the micro-jet diameter and dp/dj≈0.95-1.2, while pit's diameter-to-depth ratio is mainly negatively correlated with the micro-jet velocity. Wall pressure distribution is mostly symmetric and its maximum appears on the edge of micro-jet impingement. Obviously, the greater the micro-jet velocity is, the greater the wall pressure is. Micro pits formed after the impact of micro-jet on aluminum 1060 surface were assessed by ultrasonic cavitation test. Inversion analysis results indicate that equivalent stress, equivalent strain of the pit and impact strength, and velocity of the micro-jet are closely related with pit's diameter-to-depth ratio. For the pit's diameter-to-depth ratio of 16-68, the corresponding micro-jet velocity calculated is 310-370m/s. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Turbulent jet in confined counterflow

    Indian Academy of Sciences (India)

    The mean flowfield of a turbulent jet issuing into a confined, uniform counterflow was investigated computationally. Based on dimensional analysis, the jet penetration length was shown to scale with jet-to-counterflow momentum flux ratio. This scaling and the computational results reproduce the well-known correct limit of ...

  6. Turbulent jet in confined counterflow

    Indian Academy of Sciences (India)

    Abstract. The mean flowfield of a turbulent jet issuing into a confined, uniform counterflow was investigated computationally. Based on dimensional analysis, the jet penetration length was shown to scale with jet-to-counterflow momentum flux ratio. This scaling and the computational results reproduce the well-known correct ...

  7. Multi-jet production and jet correlations at CMS

    CERN Document Server

    Veres, Gabor

    2016-01-01

    Hadronic jet production at the LHC is an excellent testing ground for QCD. Essential components of QCD, necessary for the description of the experimental data on hadronic jets, are hard parton radiation and multiple parton interactions. The importance of these components increases for final states including multiple jets. We will show results on observables sensitive to the hard parton radiation, like the azimuthal (de)correlation between jets with small and large rapidity separation. Dijet events with a rapidity gap between them will also be presented and their fraction measured as a function of jet transverse momentum and collision energy.

  8. The physics of jets

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, W.

    1987-09-01

    Recent data on the fragmentation of quarks and gluons is discussed in the context of phenomenological models of parton fragmentation. Emphasis is placed on the experimental evidence for parton showers as compared to a fixed order QCD treatment, on new data on inclusive hadron production and on detailed studies of baryon production in jets.

  9. Kuwornu-Adjaottor, JET

    African Journals Online (AJOL)

    Kuwornu-Adjaottor, JET. Vol 33, No 1 (2013) - Articles God and the Suffering of His People Abstract PDF. ISSN: 0855-0395. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News.

  10. Fastener investigation in JET

    Energy Technology Data Exchange (ETDEWEB)

    Bunting, P., E-mail: patrick.bunting@ccfe.ac.uk; Thompson, V.; Riccardo, V.

    2016-11-15

    Highlights: • Experimental work to identify the cause of a bolt seizure inside the JET vessel. • Taguchi method used to reduce tests to 16 while covering 5 parameters. • Experimental work was unable to reproduce bolt seizure. • Thread contamination had little effect on the bolt performance. - Abstract: JET is an experimental fusion reactor consisting of magnetically confined, high temperature plasma inside a large ultra-high vacuum chamber. The inside of the chamber is protected from the hot plasma with tiles made from beryllium, tungsten, carbon composites and other materials bolted to the vessel wall. The study was carried out in response to a JET fastener seizing inside the vacuum vessel. The following study looks at characterising the magnitude of the individual factors affecting the fastener break away torque. This was carried out using a statistical approach, the Taguchi method: isolating the net effect of individual factors present in a series of tests [1](Grove and Davis, 1992). Given the severe environment within the JET vessel due to the combination of heat, ultra-high vacuum and the high contact pressure in bolt threads, the contributions of localised diffusion bonding is assessed in conjunction with various combinations of bolt and insert material.

  11. Jet printing flexible displays

    OpenAIRE

    Street, R. A.; Wong, W S; Ready, S. E.; Chabinyc, M.L; Arias, A.C.; Limb, S.; Salleo, A; Lujan, R.

    2006-01-01

    Jet printing is an interesting patterning technique for electronic devices because it requires no physical mask, has digital control of ejection, and provides good layer-to-layer registration. It also has the potential to reduce display manufacturing costs and enable roll-to-roll processing. The technique is illustrated with examples of prototype printed displays using amorphous silicon and polymer semiconductors.

  12. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of

  13. Jet-images: computer vision inspired techniques for jet tagging

    Energy Technology Data Exchange (ETDEWEB)

    Cogan, Josh; Kagan, Michael; Strauss, Emanuel; Schwarztman, Ariel [SLAC National Accelerator Laboratory,Menlo Park, CA 94028 (United States)

    2015-02-18

    We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon-initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

  14. Cathodic disbonding of organic coatings on submerged steel

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Ole oeystein

    1998-12-31

    In offshore oil production, submerged steel structures are commonly protected by an organic coating in combination with cathodic protection. The main advantage is that the coating decreases the current demand for cathodic protection. But the coating degrades with time. This thesis studies one of the most important mechanisms for coating degradation in seawater, cathodic disbonding. Seven commercial coatings and two model coatings with various pigmentations have been studied. Parameter studies, microscopy and studies of free films were used in the mechanism investigations. Exposure to simulated North Sea conditions was used in the performance studies. The effect of aluminium and glass barrier pigments on cathodic disbonding was investigated. The mechanism for the effect of the aluminium pigments on cathodic disbonding was also investigated. The transport of charge and oxygen to the steel/coating interface during cathodic disbonding was studied for two epoxy coatings. Cathodic disbonding, blistering and current demand for cathodic protection was measured for nine commercial coatings for submerged steel structures, using the ASTM-G8 standard test and a long term test under simulated North Sea conditions. The relevance of the ASTM-G8 test as a prequalification test was evaluated. 171 refs., 40 figs., 6 tabs.

  15. Period Doubling in Bubbling from a Submerged Nozzle

    Science.gov (United States)

    Dennis, Jordan; Grace, Laura; Lehman, Susan

    The timing of bubbles rising from a nozzle submerged in a viscous solution was measured to examine the period-doubling route to chaos in this system. A narrow nozzle was submerged in a mixture of water and glycerin, and nitrogen was supplied to the nozzle at a varying flow rate. The bubbles were detected using a laser and photodiode system; when the bubbles rise through the laser beam, they scatter the light so that the signal at the photodiode decreases. The period between bubbles as well as the duration of each bubble (a function of bubble size and bubble velocity) was determined, and examined as the nitrogen flow rate increased, for solutions with five different concentrations of glycerin. Bubbles were also recorded visually using a high-speed camera. Within the flow rates tested, we observed a bifurcation of the period to period-2 behavior for all solutions tested, and a further bifurcation to period-4 for all solutions except pure glycerin. The solution viscosity affected both the onset of the bifurcation and the precise bubble behavior during the bifurcation. Unusually, a short period/long period pair of bubbles recurring at a regular interval was sometimes observed in the low flow regime which is typically period-1, an observation which requires further investigation. Research supported by NSF DMR 1560093.

  16. Magnetic imaging of a submerged Roman harbour, Caesarea Maritima, Israel

    Science.gov (United States)

    Boyce, J. I.; Reinhardt, E. G.; Raban, A.; Pozza, M. R.

    2003-04-01

    The harbour built by King Herod's engineers at Caesarea represented a major advance in Roman harbour construction that incorporated the use of large (390 m^3), form-filled hydraulic concrete blocks to build an extensive foundation for the harbour moles and breakwater barriers. Marine geophysical surveys were recently conducted across the submerged harbour in an attempt to map the configuration of the buried concrete foundation. A total of 107 line km of high-resolution marine magnetic surveys (nominal 15 m line separations) and bathymetry data were acquired over a 1 km^2 area of the submerged harbour using an Overhauser marine magnetometer, integrated DGPS and single-beam (200 KHz) echosounder. The feasibility of magnetic detection of the concrete was established before the survey by magnetic susceptibility testing of concrete core samples. All concrete samples contained appreciable amounts of fe-oxide-rich volcanic ash ('pozzolana') and showed uniformly high susceptibility values (k > 10^-^4 cgs) when compared to harbour bottom sediments and building stones (k construction of the harbour moles and quays.

  17. THE INFLUENCE OF SUBMERGED MACROPHYTES ON SEDIMENTARY DIATOM ASSEMBLAGES(1).

    Science.gov (United States)

    Vermaire, Jesse C; Prairie, Yves T; Gregory-Eaves, Irene

    2011-12-01

    Submerged macrophytes are a central component of lake ecosystems; however, little is known regarding their long-term response to environmental change. We have examined the potential of diatoms as indicators of past macrophyte biomass. We first sampled periphyton to determine whether habitat was a predictor of diatom assemblage. We then sampled 41 lakes in Quebec, Canada, to evaluate whether whole-lake submerged macrophyte biomass (BiomEpiV) influenced surface sediment diatom assemblages. A multivariate regression tree (MRT) was used to construct a semiquantitative model to reconstruct past macrophyte biomass. We determined that periphytic diatom assemblages on macrophytes were significantly different from those on wood and rocks (ANOSIM R = 0.63, P macrophyte, nutrient-limited lakes (BiomEpiV ≥525 μg · L(-1) ; total phosphorus [TP] macrophyte, nutrient-limited lakes (BiomEpiV eutrophic lakes (TP ≥35 μg · L(-1) ; six lakes). A semiquantitative model correctly predicted the MRT group of the lake 71% of the time (P macrophytes have a significant influence on diatom community structure and that sedimentary diatom assemblages can be used to infer past macrophyte abundance. © 2011 Phycological Society of America.

  18. Wait or escape? Contrasting submergence tolerance strategies of Rorippa amphibia, Rorippa sylvestris and their hybrid

    NARCIS (Netherlands)

    Akman, M.; Bhikharie, A.V.; McLean, E.H.; Boonman, A.; Visser, E.J.W.; Schranz, M.E.; van Tienderen, P.H.

    2012-01-01

    Background and Aims Differential responses of closely related species to submergence can provide insight into the evolution and mechanisms of submergence tolerance. Several traits of two wetland species from habitats with contrasting flooding regimes, Rorippa amphibia and Rorippa sylvestris, as well

  19. Growth rate, protein:RNA ratio and stoichiometric homeostasis of submerged macrophytes under eutrophication stress

    OpenAIRE

    Xing W.; Shi Q.; Liu H.; Liu G.

    2016-01-01

    Growth rate hypothesis (GRH) and stoichiometric homeostasis of photoautotrophs have always been questioned. However, little is known about GRH and stoichiometric homeostasis of aquatic plants, especially submerged macrophytes. Therefore, we aim to test the GRH and explore stoichiometric homeostasis of four freshwater submerged macrophytes under eutrophication stress. At the single species level and the multi-species level, N:P ratios ...

  20. Evidence of shoreline shift on the northern Saurashtra coast: Study based on the submerged temple complex at Pindara

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Sundaresh

    . It is difficult to assign a particular reason for the submergence of the temple in discussion, however minor sea level rise and seismic activity might have played a vital role in submergence of the temple complex....

  1. Submerged beach ridge lineation and associated sedentary fauna in the innershelf of Gopalpur Coast, Orissa, Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.M.; Murthy, K.S.R.; Reddy, N.P.C.; Subrahmanyam, A.S.; Lakshminarayana, S.; Rao, M.M.M.; Sarma, K.V.L.N.S.; Premkumar, M.K.; Sree, A.; Bapuji, M.

    . (e - mail: kmrao@kadali.nio.org) RESEARCH COMMUNICATIONS CURRENT SCIENCE, VOL. 81, NO. 7, 10 OCTOBER 2001 829 mic profiling to locate the submerged roc k outcrops. Though the submerged topographic features were r e por - ted by some...

  2. EAARL-B Submerged Topography–Saint Croix, U.S. Virgin Islands, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A submerged topography Digital Elevation Model (DEM) mosaic for a portion of the submerged environs of Saint Croix, U.S. Virgin Islands, was produced from remotely...

  3. Active gas replenishment and sensing of the wetting state in a submerged superhydrophobic surface.

    Science.gov (United States)

    Lloyd, Ben P; Bartlett, Philip N; Wood, Robert J K

    2017-02-15

    Previously superhydrophobic surfaces have demonstrated effective drag reduction by trapping a lubricious gas layer on the surface with micron-sized hydrophobic features. However, prolonged reduction of drag is hindered by the dissolution of the gas into the surrounding water. This paper demonstrates a novel combination of superhydrophobic surface design and electrochemical control methods which allow quick determination of the wetted area and a gas replenishment mechanism to maintain the desirable gas filled state. Electrochemical impedance spectroscopy is used to measure the capacitance of the surface which is shown to be proportional to the solid/liquid interface area. To maintain a full gas coverage for prolonged periods the surface is held at an electrical potential which leads to hydrogen evolution. In the desired gas filled state the water does not touch the metallic area of the surface, however after gas has dissolved the water touches the metal which closes the electrochemical circuit causing hydrogen to be produced replenishing the gas in the surface and returning to the gas filled state; in this way the system is self-actuating. This type of surface and electrochemical control shows promise for applications where the gas filled state of superhydrophobic surfaces must be maintained when submerged for long periods of time.

  4. Applications of image analysis in the characterization of Streptomyces olindensis in submerged culture

    Directory of Open Access Journals (Sweden)

    Pamboukian Celso R. Denser

    2002-01-01

    Full Text Available The morphology of Streptomyces olindensis (producer of retamycin, an antitumor antibiotic grown in submerged culture was assessed by image analysis. The morphology was differentiated into four classes: pellets, clumps (or entangled filaments, branched and unbranched free filaments. Four morphological parameters were initially considered (area, convex area, perimeter, and convex perimeter but only two parameters (perimeter and convex perimeter were chosen to automatically classify the cells into the four morphological classes, using histogram analysis. Each morphological class was evaluated during growth carried out in liquid media in fermenter or shaker. It was found that pellets and clumps dominated in early growth stages in fermenter (due to the inoculum coming from a shaker cultivation and that during cultivation, the breakage of pellets and clumps caused an increase in the percentage of free filaments. The criteria of morphological classification by image analysis proposed were useful to quantify the percentage of each morphological class during fermentations and may help to establish correlations between antibiotic production and microorganism morphology.

  5. Metabolomic and Transcriptomic Comparison of Solid-State and Submerged Fermentation of Penicillium expansum KACC 40815.

    Science.gov (United States)

    Kim, Hyang Yeon; Heo, Do Yeon; Park, Hye Min; Singh, Digar; Lee, Choong Hwan

    2016-01-01

    Penicillium spp. are known to harbor a wide array of secondary metabolites with cryptic bioactivities. However, the metabolomics of these species is not well-understood in terms of different fermentation models and conditions. The present study involved metabolomics profiling and transcriptomic analysis of Penicillium expansum 40815 under solid-state fermentation (SSF) and submerged fermentation (SmF). Metabolite profiling was carried out using ultra-performance liquid chromatography quadruple time-of-flight mass spectrometry with multivariate analysis, followed by transcriptomic analyses of differentially expressed genes. In principal component analysis, the metabolite profiling data was studied under different experimental sets, including SSF and SmF. The significantly different metabolites such as polyketide metabolites (agonodepside B, rotiorin, verrucosidin, and ochrephilone) and corresponding gene transcripts (polyketide synthase, aromatic prenyltransferase, and terpenoid synthase) were primarily detected under SmF conditions. In contrast, the meroterpenoid compounds (andrastin A and C) and their genes transcripts were exclusively detected under SSF conditions. We demonstrated that the metabolite production and its corresponding gene expression levels in P. expansum 40815 were significantly influenced by the varying growth parameters and the immediate environment. This study further provides a foundation to produce specific metabolites by regulating fermentation conditions.

  6. Fungal hydrolysis in submerged fermentation for food waste treatment and fermentation feedstock preparation.

    Science.gov (United States)

    Pleissner, Daniel; Kwan, Tsz Him; Lin, Carol Sze Ki

    2014-04-01

    Potential of fungal hydrolysis in submerged fermentation by Aspergillus awamori and Aspergillus oryzae as a food waste treatment process and for preparation of fermentation feedstock has been investigated. By fungal hydrolysis, 80-90% of the initial amount of waste was reduced and degraded within 36-48 h into glucose, free amino nitrogen (FAN) and phosphate. Experiments revealed that 80-90% of starch can be converted into glucose and highest concentration of FAN obtained, when solid mashes of A. awamori and A. oryzae are successively added to fermentations at an interval of 24h. A maximal solid-to-liquid ratio of 43.2% (w/v) of food waste has been tested without a negative impact on releases of glucose, FAN and phosphate, and final concentrations of 143 g L(-1), 1.8 g L(-1) and 1.6 g L(-1) were obtained in the hydrolysate, respectively. Additionally, fungal hydrolysis as an alternative to conventional treatments for utilization of food waste is discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Metabolomic and Transcriptomic Comparison of Solid-State and Submerged Fermentation of Penicillium expansum KACC 40815.

    Directory of Open Access Journals (Sweden)

    Hyang Yeon Kim

    Full Text Available Penicillium spp. are known to harbor a wide array of secondary metabolites with cryptic bioactivities. However, the metabolomics of these species is not well-understood in terms of different fermentation models and conditions. The present study involved metabolomics profiling and transcriptomic analysis of Penicillium expansum 40815 under solid-state fermentation (SSF and submerged fermentation (SmF. Metabolite profiling was carried out using ultra-performance liquid chromatography quadruple time-of-flight mass spectrometry with multivariate analysis, followed by transcriptomic analyses of differentially expressed genes. In principal component analysis, the metabolite profiling data was studied under different experimental sets, including SSF and SmF. The significantly different metabolites such as polyketide metabolites (agonodepside B, rotiorin, verrucosidin, and ochrephilone and corresponding gene transcripts (polyketide synthase, aromatic prenyltransferase, and terpenoid synthase were primarily detected under SmF conditions. In contrast, the meroterpenoid compounds (andrastin A and C and their genes transcripts were exclusively detected under SSF conditions. We demonstrated that the metabolite production and its corresponding gene expression levels in P. expansum 40815 were significantly influenced by the varying growth parameters and the immediate environment. This study further provides a foundation to produce specific metabolites by regulating fermentation conditions.

  8. Integrated approach to characterize fouling on a flat sheet membrane gravity driven submerged membrane bioreactor

    KAUST Repository

    Fortunato, Luca

    2016-10-07

    Fouling in membrane bioreactors (MBR) is acknowledged to be complex and unclear. An integrated characterization methodology was employed in this study to understand the fouling on a gravity-driven submerged MBR (GD-SMBR). It involved the use of different analytical tools, including optical coherence tomography (OCT), liquid chromatography with organic carbon detection (LC-OCD), total organic carbon (TOC), flow cytometer (FCM), adenosine triphosphate analysis (ATP) and scanning electron microscopy (SEM). The three-dimensional (3D) biomass morphology was acquired in a real-time through non-destructive and in situ OCT scanning of 75% of the total membrane surface directly in the tank. Results showed that the biomass layer was homogeneously distributed on the membrane surface. The amount of biomass was selectively linked with final destructive autopsy techniques. The LC-OCD analysis indicated the abundance of low molecular weight (LMW) organics in the fouling composition. Three different SEM techniques were applied to investigate the detailed fouling morphology on the membrane. © 2016 Elsevier Ltd

  9. Influence of nozzle arrangement on flow and heat transfer characteristics of arrays of circular impinging jets

    Directory of Open Access Journals (Sweden)

    Perapong Tekasakul

    2013-04-01

    Full Text Available The effect of jet arrangements on flow and heat transfer characteristics was experimentally and numerically investigatedfor arrays of impinging jets. The air jets discharge from round orifices and perpendicularly impinge on a surface within arectangular duct. Both the in-line and staggered arrangements, which have an array of 6×4 nozzles, were examined. A jet-toplate distance (H and jet-to-jet distance (S were fixed at H=2D and S=3D, respectively (where D is the round orificediameter. The experiments were carried out at jet Reynolds number Re=5,000, 7,500 and 13,400. Temperature distributions onthe impingement surface were measured using a Thermochromic Liquid Crystal sheet, and Nusselt number distributions wereevaluated using an image processing method. The flow characteristics on the impingement surface were visualized using theoil film technique. The numerical simulation employed to gain insight into the fluid flow of jets between the orifice plate andthe impingement wall was via computational fluid dynamics. The results reveal that the effect of crossflow on the impingingjets for the staggered arrangement is stronger than that in the case of in-line arrangement. In the latter case of in-line arrangement, the crossflow could pass throughout the passage between the rows of jets, whereas in the former case the crossflowwas hampered by the downstream jets. The average Nusselt number of the in-line arrangement is higher than that of thestaggered arrangement by approx. 13-20% in this study.

  10. THE STUDY ON THE DURABILITY OF SUBMERGED STRUCTURE DISPLACEMENT DUE TO CONCRETE FAILURE

    Directory of Open Access Journals (Sweden)

    M. Mohd

    2016-09-01

    Full Text Available Concrete structures that exposed to marine environments are subjected to multiple deterioration mechanisms. An overview of the existing technology for submerged concrete, pressure resistant, concrete structures which related such as cracks, debonds, and delamination are discussed. Basic knowledge related to drowning durability such as submerged concrete structures in the maritime environment are the durability of a concrete and the ability to resist to weathering, chemical attack, abrasion or other deterioration processes. The measuring techniques and instrumentation for geometrical monitoring of submerged structural displacements have traditionally been categorized into two groups according to the two main groups, namely as geodetic surveying and geotechnical structural measurements of local displacements. This paper aims to study the durability of submerged concrete displacement and harmful effects of submerged concrete structures.

  11. [Effects of light on submerged macrophytes in eutrophic water: research progress].

    Science.gov (United States)

    Li-Sha, Zou; Ze-Yu, Nie; Xiao-Yan, Yao; Ji-Yan, Shi

    2013-07-01

    The restoration of submerged macrophytes is the key to remediate eutrophic water and maintain the health of aquatic ecosystem, while light is the main limiting factor. This paper summarized the factors affecting the light extinction in water and the mechanisms of light intensity affecting the physiology of submerged macrophytes, with the focuses on the metabolic mechanisms of carbon, nitrogen, and phosphorus, the responses of antioxidant enzyme system, and the feedbacks of pigment composition and concentration in the common submerged macrophytes under low light stress. Several engineering techniques applied in the ecological restoration of submerged macrophytes were presented, and the framework of the restoration of submerged macrophytes in eutrophic water was proposed. Some problems in current research and several suggestions on future research were addressed, which could help the related research and engineering practices.

  12. Enhanced heat sink with geometry induced wall-jet

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Md. Mahamudul, E-mail: sohel0991@gmail.com; Tikadar, Amitav; Bari, Fazlul; Morshed, A. K. M. M. [Department of Mechanical Engineering Bangladesh University of Engineering and Technology, Dhaka-1000. Bangladesh (Bangladesh)

    2016-07-12

    Mini-channels embedded in solid matrix have already proven to be a very efficient way of electronic cooling. Traditional mini-channel heat sinks consist of single layer of parallel channels. Although mini-channel heat sink can achieve very high heat flux, its pumping requirement for circulating liquid through the channel increase very sharply as the flow velocity increases. The pumping requirements of the heat sink can be reduced by increasing its performance. In this paper a novel approach to increase the thermal performance of the mini-channel heat sink is proposed through geometry induced wall jet which is a passive technique. Geometric irregularities along the channel length causes abrupt pressure change between the channels which causes cross flow through the interconnections thus one channel faces suction and other channel jet action. This suction and jet action disrupts boundary layer causing enhanced heat transfer performance. A CFD model has been developed using commercially available software package FLUENT to evaluate the technique. A parametric study of the velocities and the effect of the position of the wall-jets have been performed. Significant reduction in thermal resistance has been observed for wall-jets, it is also observed that this reduction in thermal resistance is dependent on the position and shape of the wall jet.

  13. Study on the wiping gas jet in continuous galvanizing line

    Science.gov (United States)

    Kweon, Yong-Hun; Kim, Heuy-Dong

    2011-09-01

    In the continuous hot-dip galvanizing process, the gas-jet wiping is used to control the coating thickness of moving steel strip. The high speed gas-jet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. The coating thickness is generally influenced on the flow characteristics of wiping gas-jet such as the impinging pressure distribution, pressure gradient and shear stress distribution on the surface of strip. The flow characteristics of wiping gas-jet mentioned above depends upon considerably both the process operating conditions such as the nozzle pressure, nozzle-to-strip distance and line speed, and the geometry of gas-jet wiping apparatus such as the height of nozzle slot. In the present study, the effect of the geometry of nozzle on the coating thickness is investigated with the help of a computational fluid dynamics method. The height of nozzle slot is varied in the range of 0.6mm to 1.7mm. A finite volume method (FVM) is employed to solve two-dimensional, steady, compressible Navier-Stokes equations. Based upon the results obtained, the effect of the height of nozzle slot in the gas-jet wiping process is discussed in detail. The computational results show that for a given standoff distance between the nozzle to the strip, the effective height of nozzle slot exists in achieving thinner coating thickness.

  14. A submerged membrane bioreactor with pendulum type oscillation (PTO) for oily wastewater treatment: membrane permeability and fouling control.

    Science.gov (United States)

    Qin, Lei; Fan, Zheng; Xu, Lusheng; Zhang, Guoliang; Wang, Guanghui; Wu, Dexin; Long, Xuwei; Meng, Qin

    2015-05-01

    In this study, a novel submerged membrane bioreactor (SMBR) with pendulum type oscillation (PTO) hollow fiber membrane modules was developed to treat oily wastewater and control the problem of membrane fouling. To assess the potential of PTO membrane modules, the effect of oscillation orientation and frequency on membrane permeability was investigated in detail. The forces exerted on sludge flocs in the oscillating SMBR were analyzed to evaluate the impact of membrane oscillating on the cake layer resistance reduction. Results showed that the optimized PTO SMBR system exhibited 11 times higher membrane permeability and better fouling controllability than the conventional MBR system. By hydrodynamic analysis, it was found that the cooperative effect of bubble-induced turbulence and membrane oscillation in PTO SMBR system generated strong shear stress at liquid-membrane interface in vertical and horizontal direction and effectively hindered the particles from depositing on membrane surface. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Study on submerged anaerobic membrane bioreactor (SAMBR) treating high suspended solids raw tannery wastewater for biogas production.

    Science.gov (United States)

    Umaiyakunjaram, R; Shanmugam, P

    2016-09-01

    This study deals with the treatment of high suspended solids raw tannery wastewater using flat sheet Submerged Anaerobic Membrane (0.4μm) Bioreactor (SAMBR) acclimatized with hypersaline anaerobic seed sludge for recovering biogas. The treatability of SAMBR achieved higher CODremoval efficiency (90%) and biogas yield (0.160L.g(-1) CODremoved) coincided with high r(2) values between permeate flux and TSS (0.95), biogas and COD removed (0.96). The acidification of hypersaline influent wastewater by biogas mixing with high CO2, achieved quadruplet benefit of gas liquid and solid separation, in-situ pH and NH3 control, in-situ CH4 enrichment, and prevention of membrane fouling. The initial high VFA became stable as time elapsed reveals the hydrolysing ability of particulate COD into soluble COD and into biogas, confirms the suitability of SAMBR for high suspended solids tannery wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Algae Bioreactor Using Submerged Enclosures with Semi-Permeable Membranes

    Science.gov (United States)

    Trent, Jonathan D (Inventor); Gormly, Sherwin J (Inventor); Embaye, Tsegereda N (Inventor); Delzeit, Lance D (Inventor); Flynn, Michael T (Inventor); Liggett, Travis A (Inventor); Buckwalter, Patrick W (Inventor); Baertsch, Robert (Inventor)

    2013-01-01

    Methods for producing hydrocarbons, including oil, by processing algae and/or other micro-organisms in an aquatic environment. Flexible bags (e.g., plastic) with CO.sub.2/O.sub.2 exchange membranes, suspended at a controllable depth in a first liquid (e.g., seawater), receive a second liquid (e.g., liquid effluent from a "dead zone") containing seeds for algae growth. The algae are cultivated and harvested in the bags, after most of the second liquid is removed by forward osmosis through liquid exchange membranes. The algae are removed and processed, and the bags are cleaned and reused.

  17. Nonlinear Instabilities on an Axisymmetric Ferrofluid Jet

    Science.gov (United States)

    Cornish, Michael; Papageorgiou, Demetrios

    2017-11-01

    The stability properties of an inviscid axisymmetric ferrofluid jet running over a current carrying rod are investigated. The rod generates an azimuthal magnetic field which can fully stabilize the Rayleigh-plateau instability for a sufficiently large magnetic field. However, long wave instability can occur when the magnetic field is below critical; this regime has not been studied nonlinearly unlike the above critical regime where the magnetic stabilization property has led to theoretical and experimental discoveries of solitary waves on the ferrofluid jet. We study the flow asymptotically near the critical value of the magnetic field. In the stable regime, we derive the Boussinesq equation. Our interest is in the unstable regime, where magnetic forces are slightly smaller than capillary forces. The Rayleigh-plateau instability is no longer suppressed and a weakly nonlinear long wave model is derived and studied analytically and computationally. The final part of the study follows the nonlinear evolution of the free surface for magnetic fields away from the critical level. A fully nonlinear long-wave theory will be used to derive reduced model equations to evaluate the nonlinear competition between capillary instability of the liquid jet and the stabilizing magnetic field.

  18. Large-eddy simulation of cavitating nozzle flow and primary jet break-up

    NARCIS (Netherlands)

    Örley, F.; Trummler, T.; Hickel, S.; Mihatsch, M.S.; Schmidt, S.J.; Adams, N.A.

    2015-01-01

    We employ a barotropic two-phase/two-fluid model to study the primary break-up of cavitating liquid jets emanating from a rectangular nozzle, which resembles a high aspect-ratio slot flow. All components (i.e., gas, liquid, and vapor) are represented by a homogeneous mixture approach. The cavitating

  19. Acoustic streaming jets: A scaling and dimensional analysis

    Energy Technology Data Exchange (ETDEWEB)

    Botton, V., E-mail: valery.botton@insa-lyon.fr; Henry, D.; Millet, S.; Ben-Hadid, H. [LMFA, UMR CNRS 5509, Université de Lyon, ECL/INSA Lyon/Univ. Lyon 1, 36 avenue Guy deCollongue, 69134 Ecully Cedex (France); Moudjed, B. [LMFA, UMR CNRS 5509, Université de Lyon, ECL/INSA Lyon/Univ. Lyon 1, 36 avenue Guy deCollongue, 69134 Ecully Cedex (France); LIEFT, CEA-Saclay, 91191 Gif-sur-Yvette cedex (France); Garandet, J. P. [LIEFT, CEA-Saclay, 91191 Gif-sur-Yvette cedex (France)

    2015-10-28

    We present our work on acoustic streaming free jets driven by ultrasonic beams in liquids. These jets are steady flows generated far from walls by progressive acoustic waves. As can be seen on figure 1, our set-up, denominated AStrID for Acoustic Streaming Investigation Device, is made of a water tank in which a 29 mm plane source emits continuous ultrasonic waves at typically 2 MHz. Our approach combines an experimental characterization of both the acoustic pressure field (hydrophone) and the obtained acoustic streaming velocity field (PIV visualization) on one hand, with CFD using an incompressible Navier-Stokes solver on the other hand.

  20. Leaf gas films contribute to rice (Oryza sativa) submergence tolerance during saline floods

    DEFF Research Database (Denmark)

    Herzog, Max; Konnerup, Dennis; Pedersen, Ole

    2018-01-01

    Floods and salinization of agricultural land adversely impact global rice production. We investigated whether gas films on leaves of submerged rice delay salt entry during saline submergence. Two-week-old plants with leaf gas films (+GF) or with gas films experimentally removed (-GF) were submerg...

  1. Description of the ATLAS jet veto measurement and jet gap jet events at hadronic colliders

    CERN Document Server

    Royon, C

    2014-01-01

    We present a new QCD description of the ATLAS jet veto measurement, using the Banfi- Marchesini-Smye equation to constrain the inter-jet QCD radiation. This equation resums emis- sions of soft gluons at large angles and leads to a very good description of data. We also investigate jet gap jet events in hadron-hadron collisions, in which two jets are produced and separated by a large rapidity gap. Using a renormalisation-group improved NLL kernel implemented in the HERWIG Monte Carlo program, we show that the BFKL predictions are in good agreement with the Tevatron data, and present predictions that could be tested at the LHC.

  2. Experiment and simulation study of laser dicing silicon with water-jet

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Jiading; Long, Yuhong, E-mail: longyuhong@guet.edu.cn; Tong, Youqun; Yang, Xiaoqing; Zhang, Bin; Zhou, Zupeng

    2016-11-30

    Highlights: • The explosive melt expulsion could be a dominant process for the laser ablating silicon in liquids with ns-pulsed laser of 1064 nm irradiating. • Self-focusing phenomenon was found and its causes are analyzed. • SPH modeling technique was employed to understand the effect of water and water-jet on debris removal during water-jet laser machining. - Abstract: Water-jet laser processing is an internationally advanced technique, which combines the advantages of laser processing with water jet cutting. In the study, the experiment of water-jet laser dicing are conducted with ns pulsed laser of 1064 nm irradiating, and Smooth Particle Hydrodynamic (SPH) technique by AUTODYN software was modeled to research the fluid dynamics of water and melt when water jet impacting molten material. The silicon surface morphology of the irradiated spots has an appearance as one can see in porous formation. The surface morphology exhibits a large number of cavities which indicates as bubble nucleation sites. The observed surface morphology shows that the explosive melt expulsion could be a dominant process for the laser ablating silicon in liquids with nanosecond pulse laser of 1064 nm irradiating. Self-focusing phenomenon was found and its causes are analyzed. Smooth Particle Hydrodynamic (SPH) modeling technique was employed to understand the effect of water and water-jet on debris removal during water-jet laser machining.

  3. Jet Physics in ATLAS

    CERN Document Server

    Sandoval, C; The ATLAS collaboration

    2012-01-01

    Measurements of hadronic jets provide tests of strong interactions which are interesting both in their own right and as backgrounds to many New Physics searches. It is also through tests of Quantum Chromodynamics that new physics may be discovered. The extensive dataset recorded with the ATLAS detector throughout the 7 TeV and 8 TeV centre-of-mass LHC operation periods allows QCD to be probed at distances never reached before. We present a review of selected ATLAS jet physics measurements. These measurements constitute precision tests of QCD in a new energy regime, and show sensitivity to the parton densities in the proton and to the value of the strong coupling, alpha_s.

  4. Electrostatic charge characteristics of jet nebulized aerosols.

    Science.gov (United States)

    Kwok, Philip Chi Lip; Trietsch, Sebastiaan J; Kumon, Michiko; Chan, Hak-Kim

    2010-06-01

    Liquid droplets can be spontaneously charged in the absence of applied electric fields by spraying. It has been shown by computational simulation that charges may influence particle deposition in the airways. The electrostatic properties of jet nebulized aerosols and their potential effects on lung deposition have hardly been studied. A modified electrical low pressure impactor (ELPI) was employed to characterize the aerosol charges generated from jet nebulized commercial products. The charge and size measurements were conducted at 50% RH and 22 degrees C with a modified ELPI. Ventolin, Bricanyl, and Atrovent were nebulized using PARI LC Plus jet nebulizers coupled to a DeVilbiss Pulmo-Aide compressor. The aerosols were sampled in 30-sec durations. The drug deposits on the impactor stages were assayed chemically using high-performance liquid chromatography (HPLC). The charges of nebulized deionized water, isotonic saline, and the three commercial products diluted with saline were also measured to analyze the contributions of the major nebule ingredients on charging. No mass assays were performed on these runs. All three commercial nebules generated net negative charges. The magnitude of the charges reduced over the period of nebulization. Ventolin and Bricanyl yielded similar charge profiles. Highly variable charges were produced from deionized water. On the other hand, nebulized saline reproducibly generated net positive charges. Diluted commercial nebules showed charge polarity inversion. The charge profiles of diluted salbutamol and terbutaline solutions resembled those of saline, while the charges from diluted ipratropium solutions fluctuated near neutrality. The charge profiles were shown to be influenced by the concentration and physicochemical properties of the drugs, as well as the history of nebulization. The drugs may have unique isoelectric concentrations in saline at which the nebulized droplets would carry near-zero charges. According to results from

  5. Surface-Wettability Patterning for Distributing High-Momentum Water Jets on Porous Polymeric Substrates.

    Science.gov (United States)

    Sen, Uddalok; Chatterjee, Souvick; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Dodge, Richard; Yu, Lisha; Megaridis, Constantine M

    2018-02-07

    Liquid jet impingement on porous materials is particularly important in many applications of heat transfer, filtration, or in incontinence products. Generally, it is desired that the liquid not penetrate the substrate at or near the point of jet impact, but rather be distributed over a wider area before reaching the back side. A facile wettability-patterning technique is presented, whereby a water jet impinging orthogonally on a wettability-patterned nonwoven substrate is distributed on the top surface and through the porous matrix, and ultimately dispensed from prespecified points underneath the sample. A systematic approach is adopted to identify the optimum design that allows for a uniform distribution of the liquid on horizontally mounted substrates of ∼50 cm 2 area, with minimal or no spilling over the sample edges at jet flow rates exceeding 1 L/min. The effect of the location of jet impingement on liquid distribution is also studied, and the design is observed to perform well even under offset jet impact conditions.

  6. Critical Assessment of Temperature Distribution in Submerged Arc Welding Process

    Directory of Open Access Journals (Sweden)

    Vineet Negi

    2013-01-01

    Full Text Available Temperature distribution during any welding process holds the key for understanding and predicting several important welding attributes like heat affected zone, microstructure of the weld, residual stress, and distortion during welding. The accuracy of the analytical approaches for modeling temperature distribution during welding has been constrained by oversimplified assumptions regarding boundary conditions and material properties. In this paper, an attempt has been made to model the temperature distribution during submerged arc welding process using finite element modeling technique implemented in ANSYS v12. In the present analysis, heat source is assumed to be double-ellipsoidal with Gaussian volumetric heat generation. Furthermore, variation of material properties with temperature and both convective and radiant heat loss boundary condition have been considered. The predicted temperature distribution is then validated against the experimental results obtained by thermal imaging of the welded plate, and they are found to be in a good agreement.

  7. Arc characteristics of submerged arc welding with stainless steel wire

    Science.gov (United States)

    Li, Ke; Wu, Zhi-sheng; Liu, Cui-rong; Chen, Feng-hua

    2014-08-01

    The arc characteristics of submerged arc welding (SAW) with stainless steel wire were studied by using Analysator Hannover (AH). The tests were carried out under the same preset arc voltage combined with different welding currents. By comparing the probability density distribution (PDD) curves of arc voltage and welding current, the changes were analyzed, the metal transfer mode in SAW was deduced, and the characteristics of a stable arc were summarized. The analysis results show that, with an increase of welding parameters, the short-circuiting peak in the PDD curves of arc voltage decreases gradually until it disappears, and the dominant metal transfer mode changes from flux-wall guided transfer to projected transfer and then to streaming transfer. Moreover, when the PDD curves of arc voltage are both unimodal and generally symmetrical, the greater the peak probability and the smaller the peak span, the more stable the arc becomes.

  8. Numerical study on tsunami hazard mitigation using a submerged breakwater.

    Science.gov (United States)

    Ha, Taemin; Yoo, Jeseon; Han, Sejong; Cho, Yong-Sik

    2014-01-01

    Most coastal structures have been built in surf zones to protect coastal areas. In general, the transformation of waves in the surf zone is quite complicated and numerous hazards to coastal communities may be associated with such phenomena. Therefore, the behavior of waves in the surf zone should be carefully analyzed and predicted. Furthermore, an accurate analysis of deformed waves around coastal structures is directly related to the construction of economically sound and safe coastal structures because wave height plays an important role in determining the weight and shape of a levee body or armoring material. In this study, a numerical model using a large eddy simulation is employed to predict the runup heights of nonlinear waves that passed a submerged structure in the surf zone. Reduced runup heights are also predicted, and their characteristics in terms of wave reflection, transmission, and dissipation coefficients are investigated.

  9. Numerical Study on Tsunami Hazard Mitigation Using a Submerged Breakwater

    Directory of Open Access Journals (Sweden)

    Taemin Ha

    2014-01-01

    Full Text Available Most coastal structures have been built in surf zones to protect coastal areas. In general, the transformation of waves in the surf zone is quite complicated and numerous hazards to coastal communities may be associated with such phenomena. Therefore, the behavior of waves in the surf zone should be carefully analyzed and predicted. Furthermore, an accurate analysis of deformed waves around coastal structures is directly related to the construction of economically sound and safe coastal structures because wave height plays an important role in determining the weight and shape of a levee body or armoring material. In this study, a numerical model using a large eddy simulation is employed to predict the runup heights of nonlinear waves that passed a submerged structure in the surf zone. Reduced runup heights are also predicted, and their characteristics in terms of wave reflection, transmission, and dissipation coefficients are investigated.

  10. Phytoremediation of arsenic in submerged soil by wetland plants.

    Science.gov (United States)

    Jomjun, Nateewattana; Siripen, Trichaiyaporn; Maliwan, Saeouy; Jintapat, Nateewattana; Prasak, Thavornyutikarn; Somporn, Choonluchanon; Petch, Pengchai

    2011-01-01

    Wetland aquatic plants including Canna glauca L., Colocasia esculenta L. Schott, Cyperus papyrus L. and Typha angustifolia L. were used in the phytoremediation of submerged soil polluted by arsenic (As). Cyperus papyrus L. was noticed as the largest biomass producer which has arsenic accumulation capacity of 130-172 mg As/kg plant. In terms of arsenic removal rate, however, Colocasia esculenta L. was recognized as the largest and fastest arsenic remover in this study. Its arsenic removal rate was 68 mg As/m2/day while those rates of Canna glauca L., Cyperus papyrus L. and Typha angustifolia L. were 61 mg As/m2/day, 56 mg As/m2/day, and 56 mg As/m2/day, respectively. Although the 4 aquatic plants were inferior in arsenic accumulation, their high arsenic removal rates were observed. Phytostabilization should be probable for the application of these plants.

  11. Minimizing downstream scour due to submerged hydraulic jump using corrugated

    Directory of Open Access Journals (Sweden)

    Hossam Mohamed Ali

    2014-12-01

    Full Text Available Local scour downstream of hydraulic structures due to hydraulic jump is considered one of the tedious and complicated problems facing their stability. Throughout this paper, an experimental study was conducted to study the effect of using different spaced corrugated aprons on the downstream local scour due to submerged jump. Sixty runs were carried out in a horizontal rectangular flume to determine the optimal corrugation wavelength which minimizing the scour. A case of flat apron included to estimate the influence of corrugated aprons on scour holes dimensions. Two types of non-cohesive soil were used. Experiments were performed for a range of Froude numbers between 1.68 and 9.29. The results showed that using spaced triangular corrugated aprons minimize the scour depth and length of fine sand by average percentage of 63.4% and 30.2%, respectively and for coarse sand by 44.2% and 20.6% in comparing with classical jump.

  12. Microbial production of four biodegradable siderophores under submerged fermentation.

    Science.gov (United States)

    Fazary, Ahmed E; Al-Shihri, Ayed S; Alfaifi, Mohammad Y; Saleh, Kamel A; Alshehri, Mohammed A; Elbehairi, Serag Eldin I; Ju, Yi-Hsu

    2016-07-01

    Four siderophore analogues were isolated and purified from Escherichia coli, Bacillus spp. ST13, and Streptomyces pilosus microorganisms under some specific submerged fermentation conditions. In order to evaluate the highest production of this siderophore analogues through the growth, a rapid spectrophotometric screening semi-quantitative method was used, in which interestingly the analogues were isolated in its own form not its iron chelate. After chromatographic separation, the chemical structures of the isolated and purified siderophores were illustrated using detailed spectroscopic techniques. The biodegradation studies were done on that four novel isolated and purified siderophores following OECD protocols. In addition, the bioactivities of these siderophores and their iron complexes were examined and evaluated. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Development of Submerged Entry Nozzles that Resist Clogging

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Jeffrey D. Smith; Kent D. Peasle

    2002-10-14

    Accretion formation and the associated clogging of SENs is a major problem for the steel industry leading to decreased strand speed, premature changing of SENs or strand termination and the associated reductions in productivity, consistency, and steel quality. A program to evaluate potentially clog resistance materials was initiated at the University of Missouri-Rolla. The main objective of the research effort was to identify combinations of steelmaking and refractory practices that would yield improved accretion resistance for tundish nozzles and submerged entry nozzles. A number of tasks were identified during the initial kick-off meeting and each was completed with two exceptions, the thermal shock validation and the industrial trials. Not completing these two tasks related to not having access to industrial scale production facilities. Though much of the results and information generated in the project is of proprietary nature.

  14. Slag-metal equilibrium during submerged arc welding

    Science.gov (United States)

    Chai, C. S.; Eagar, T. W.

    1981-09-01

    A thermodynamic model of the equilibria existing between the slag and the weld metal during submerged arc welding is presented. As formulated, the model applies only to fused neutral fluxes containing less than 20 pct CaF2, however some results indicate that the model may be useful in more general cases as well. The model is shown to be capable of predicting the gain or loss of both Mn and Si over a wide range of baseplate, electrode and flux compositions. At large deviations from the predicted equilibrium, the experimental results indicate considerable variability in the amount of Mn or Si transferred between the slag and metal phases, while closer to the calculated equilibrium, the extent of metal transfer becomes more predictable. The variability in metal transfer rate at large deviations from equilibrium may be explained by variations between the bulk and the surface concentrations of Mn and Si in both metal and slag phases.

  15. Endodontic Treatment in Submerged Roots: A Case Report

    Directory of Open Access Journals (Sweden)

    Hemalatha Pameshwar Hiremath

    2010-06-01

    Full Text Available Alveolar ridge resorption has long been considered an unavoidable consequence of tooth extraction. While the extent and pattern of resorption is variable among individuals, there is a progressive loss of ridge contour as a result of physiologic bone remodeling. Even today, with best modalities of tooth preservation, there is a group of elderly individuals who do not benefit from modern preventive practices and who now present a dilemma in terms of maintaining the masticatory apparatus necessary for nutrition. Even with excellent dental care, such patients experience abrasion of the natural tooth crowns with age, and embedded roots are left within the alveolar bone. According to old concepts of dental care, extraction of these roots would have been recommended, but today’s goal of excellence in endodontics dictates otherwise. We report a case in which vital and non-vital root submergence was carried out to prevent alveolar ridge reduction.

  16. Development of New Submergence Tolerant Rice Variety for Bangladesh Using Marker-Assisted Backcrossing

    Directory of Open Access Journals (Sweden)

    Khandakar Md Iftekharuddaula

    2015-01-01

    Full Text Available Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize linkage drag by BC2F2 generation. Without recombinant selection, the introgression size in the backcross recombinant lines (BRLs was approximately 15 Mb on the carrier chromosome. The BRLs were found submergence tolerance compared to the check varieties under complete submergence for two weeks at Bangladesh Rice Research Institute, and produced higher yield compared to the isogenic Sub1-line under controlled submerged condition. The BRL IR85260-66-654-Gaz2 was released as BRRI dhan52 in 2010, which was the first high yielding submergence tolerant variety in Bangladesh. BRRI dhan52 produced grain yield ranging from 4.2 to 5.2 t/hm2 under different flash flood prone areas of Bangladesh in three consecutive seasons. The study demonstrated the efficiency of recombinant selection and better adaptability of the newly released submergence tolerant high yielding variety in flash flood prone different areas of the country with respect to submergence tolerance and yield potential.

  17. Physiological and transcriptomic characterization of submergence and reoxygenation responses in soybean seedlings.

    Science.gov (United States)

    Tamang, Bishal G; Magliozzi, Joseph O; Maroof, M A Saghai; Fukao, Takeshi

    2014-10-01

    Complete inundation at the early seedling stage is a common environmental constraint for soybean production throughout the world. As floodwaters subside, submerged seedlings are subsequently exposed to reoxygenation stress in the natural progression of a flood event. Here, we characterized the fundamental acclimation responses to submergence and reoxygenation in soybean at the seedling establishment stage. Approximately 90% of seedlings succumbed during 3 d of inundation under constant darkness, whereas 10 d of submergence were lethal to over 90% of seedlings under 12 h light/12 h dark cycles, indicating the significance of underwater photosynthesis in seedling survival. Submergence rapidly decreased the abundance of carbohydrate reserves and ATP in aerial tissue of seedlings although chlorophyll breakdown was not observed. The carbohydrate and ATP contents were recovered upon de-submergence, but sudden exposure to oxygen also induced lipid peroxidation, confirming that reoxygenation induced oxidative stress. Whole transcriptome analysis recognized genome-scale reconfiguration of gene expression that regulates various signalling and metabolic pathways under submergence and reoxygenation. Comparative analysis of differentially regulated genes in shoots and roots of soybean and other plants defines conserved, organ-specific and species-specific adjustments which enhance adaptability to submergence and reoxygenation through different metabolic pathways. © 2014 John Wiley & Sons Ltd.

  18. Submergence induced changes of molecular species in membrane lipids in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Mulan Wang

    2016-06-01

    Full Text Available The composition of membrane lipids is sensitive to environmental stresses. Submergence is a type of stress often encountered by plants. However, how the molecular species of membrane lipids respond to submergence has not yet been characterised. In this study, we used a lipidomic approach to profile the molecular species of membrane lipids in whole plants of Arabidopsis thaliana that were completely submerged for three days. The plants survived one day of submergence, after which, we found that the total membrane lipids were only subtly decreased, showing significant decreases of monogalactosyldiacylglycerol (MGDG and phosphatidylcholine (PC and an increase of phosphatidic acid (PA; however, the basic lipid composition was retained. In contrast, three days of submergence caused plants to die, and the membranes deteriorated via the rapid loss of 96% of lipid content together with a 229% increase in PA. The turnover of molecular species from PG and MGDG to PA indicated that submergence-induced lipid changes occurred through PA-mediated degradation. In addition, molecular species of extraplastidic PG degraded sooner than plastidic ones, lyso-phospholipids exhibited various patterns of change, and the double-bond index (DBI remained unchanged until membrane deterioration. Our results revealed the unique changes of membrane lipids upon submergence and suggested that the major cause of the massive lipid degradation could be anoxia.

  19. The Performance and Fouling Control of Submerged Hollow Fiber (HF Systems: A Review

    Directory of Open Access Journals (Sweden)

    Ebrahim Akhondi

    2017-07-01

    Full Text Available The submerged membrane filtration concept is well-established for low-pressure microfiltration (MF and ultrafiltration (UF applications in the water industry, and has become a mainstream technology for surface-water treatment, pretreatment prior to reverse osmosis (RO, and membrane bioreactors (MBRs. Compared to submerged flat sheet (FS membranes, submerged hollow fiber (HF membranes are more common due to their advantages of higher packing density, the ability to induce movement by mechanisms such as bubbling, and the feasibility of backwashing. In view of the importance of submerged HF processes, this review aims to provide a comprehensive landscape of the current state-of-the-art systems, to serve as a guide for further improvements in submerged HF membranes and their applications. The topics covered include recent developments in submerged hollow fiber membrane systems, the challenges and developments in fouling-control methods, and treatment protocols for membrane permeability recovery. The highlighted research opportunities include optimizing the various means to manipulate the hydrodynamics for fouling mitigation, developing online monitoring devices, and extending the submerged HF concept beyond filtration.

  20. Oxygen absorption by adventitious roots promotes the survival of completely submerged terrestrial plants.

    Science.gov (United States)

    Ayi, Qiaoli; Zeng, Bo; Liu, Jianhui; Li, Siqi; van Bodegom, Peter M; Cornelissen, Johannes H C

    2016-04-10

    Flooding imposes stress upon terrestrial plants because it results in oxygen deficiency, which is considered a major problem for submerged plants. A common response of terrestrial plants to flooding is the formation of aquatic adventitious roots. Some studies have shown that adventitious roots on submerged plants are capable of absorbing water and nutrients. However, there is no experimental evidence for the possible oxygen uptake function of adventitious roots or for how important this function might be for the survival of plants during prolonged submergence. This study aims to investigate whether adventitious roots absorb oxygen from the water column, and whether this new function is beneficial to the survival of completely submerged plants. TakingAlternanthera philoxeroides(Mart.) Griseb. as a representative species, the profiling of the underwater oxygen gradient towards living and dead adventitious roots on completely submerged plants was conducted, the oxygen concentration in stem nodes with and without adventitious roots was measured, and the growth, survival and non-structural carbohydrate content of completely submerged plants with and without adventitious roots was investigated. Oxygen profiles in the water column of adventitious roots showed that adventitious roots absorbed oxygen from water. It is found that the oxygen concentration in stem nodes having adventitious roots was higher than that in stem nodes without adventitious roots, which implies that the oxygen absorbed by adventitious roots from water was subsequently transported from the roots to other plant tissues. Compared with plants whose adventitious roots had been pruned, those with intact adventitious roots had slower leaf shedding, slower plant mass reduction, more efficient carbohydrate economy and prolonged survival when completely submerged. The adventitious roots ofA. philoxeroidesformed upon submergence can absorb oxygen from ambient water, thereby alleviating the adverse effects of

  1. Pileup subtraction for jet shapes

    CERN Document Server

    Soyez, Gregory; Kim, Jihun; Dutta, Souvik; Cacciari, Matteo

    2013-01-01

    Jet shapes have the potential to play a role in many LHC analyses, for example in quark-gluon discrimination or jet substructure analyses for hadronic decays of boosted heavy objects. Most shapes, however, are significantly affected by pileup. We introduce a general method to correct for pileup effects in shapes, which acts event-by-event and jet-by-jet, and accounts also for hadron masses. It involves a numerical determination, for each jet, of a given shape's susceptibility to pileup. Together with existing techniques for determining the level of pileup, this then enables an extrapolation to zero pileup. The method can be used for a wide range of jet shapes and we show its successful application in the context of quark/gluon discrimination and top-tagging.

  2. An Investigation of the Measurement of Jet Shape Dependence on Jet Mass using Pythia

    Science.gov (United States)

    Rao, Esha; Sevil Salur Team

    2017-09-01

    Jet mass, as measured by the jet reconstruction algorithm, is expected to be constrained by the virtuality of jets resulting in considerable effects on the jet shapes and fragmentation functions. In this poster, we will be showing the jet shape variable dependence on jet mass in Monte Carlo simulations for RHIC energies. This study can be used to optimize the kinematic selection of jets in data, such as the transverse momenta of jet constituents.

  3. Anti-Growth Factors Associated with Pleurotus ostreatus in a Submerged Liquid Fermentation

    Directory of Open Access Journals (Sweden)

    Juliet B. Akinyele

    2012-09-01

    Full Text Available Aims: Previous studies had revealed that cultivation of Pleurotus ostreatus is often met with a lot of challenges ranging from environmental to biological factors which adversely affect the successful cultivation of the mushroom. Hence, a need to determine factors against mycelia colonization of substrate during mushroom’s cultivation.Methodology and Result: Conventional streak method was employed to establish the percentage inhibition as well as intercolony distance between the test organisms obtained from the infected substrate and mycelia of the mushroom during substrate colonization. The test organisms are: a fungus, Kutilakesopsis macalpineae and a bacterium,Pseudomonas tolaasii. The effect of pH and temperature on the mycelia growth of P. ostreatus was also investigated. There was a gradual increase in the percentage inhibition from 33.3 % at 24 h to 75.0 % at 168 h for K. macalpineae and 37.5 % at 24 h to 70.0 at 168 h for P. tolaasii. The inter-colony distance between the antagonists and the mushroom mycelium gradually decreased. Optical density of the mycelium growth was at its optimum at pH 4.5 and temperature of25 °C respectively. In vitro study also showed a significant increase in the optical density from 0.855±0.03 at 24 h to 1.316±0.02 at 168 h in the absence of test antagonist as against 0.812±0.06 and 0.79±0.02 at 24 h to 1.103±0.03 and 0.902±0.03 at 168 h when K. macalpineae and P.tolaasii were used as test antagonistic respectively.Conclusion, significance and impact of study: Sterilization of substrate is essential to avoid contamination during mycelia colonization. Also, slightly acidic medium and temperature control is necessary for high yield of fruit bodies.

  4. Study on the influences of interaction behaviors between multiple combustion-gas jets on expansion characteristics of Taylor cavities

    Science.gov (United States)

    Xue, Xiaochun; Yu, Yonggang; Zhang, Qi

    2015-10-01

    The purpose of this study is to investigate means of controlling the interior ballistic stability of a bulk-loaded propellant gun (BLPG). Experiments on the interaction of twin combustion gas jets and liquid medium in a cylindrical stepped-wall combustion chamber are conducted in detail to obtain time series processes of jet expansion, and a numerical simulation under the same working conditions is also conducted to verify the reliability of the numerical method by comparing numerical results and experimental results. From this, numerical simulations on mutual interference and expansion characteristics of multiple combustion gas jets (four, six, and eight jets) in liquid medium are carried out, and the distribution characteristic of pressure, velocity, temperature, and evolutionary processes of Taylor cavities and streamlines of jet flow field are obtained in detail. The results of numerical simulations show that when different numbers of combustion gas jets expand in liquid medium, there are two different types of vortices in the jet flow field, including corner vortices of liquid phase near the step and backflow vortices of gas phase within Taylor cavities. Because of these two types of vortices, the radial expansion characteristic of the jets is increased, while changing numbers of combustion gas jets can restrain Kelvin-Helmholtz instability to a certain degree in jet expansion processes, which can at last realize the goal of controlling the interior ballistic stability of a BLPG. The optimum method for both suppressing Kelvin-Helmholtz instability and promoting radial expansion of Taylor cavities can be determined by analyzing the change of characteristic parameters in a jet flow field.

  5. Jet initiation of PBX 9502

    Energy Technology Data Exchange (ETDEWEB)

    McAfee, J.M.

    1987-07-01

    This report details the progress of an effort to determine the quantitative aspects of the initiation of PBX 9502 (95% TATB, 5% Kel-F 800) by copper jets. The particular jet used was that produced by the LAW warhead (66-mm diameter, 42/sup 0/ angle cone, copper-lined, conical shaped charge). Fifteen experiments, in various configurations, have been fired to define the essential parameters for quantitatively measuring the jet performance and initiation of bare PBX 9502. 7 refs., 8 figs.

  6. Liquid flexRIXS: A RIXS endstation for molecular systems at BESSY II

    Directory of Open Access Journals (Sweden)

    Annette Pietzsch

    2016-11-01

    Full Text Available The liquid flexRIXS endstation is dedicated to resonant inelastic x-ray scattering experiments on liquid samples and gasses in the soft x-ray range. The liquids are injected into the chamber via a liquid jet system whereas gasses and also small amounts of liquids can be investigated using a liquid/gas flow cell. The MCP-based RIXS spectrometer allows for a resolving power of better than 1000.

  7. Interaction of Submerged Breakwater by a Solitary Wave Using WC-SPH Method

    Directory of Open Access Journals (Sweden)

    Afshin Mansouri

    2014-01-01

    Full Text Available Interaction of a solitary wave and submerged breakwater is studied in a meshless, Lagrangian approach. For this purpose, a two-dimensional smoothed particle hydrodynamics (SPH code is developed. Furthermore, an extensive set of simulations is conducted. In the first step, the generated solitary wave is validated. Subsequently, the interaction of solitary wave and submerged breakwater is investigated thoroughly. Results of the interaction of solitary wave and a submerged breakwater are also shown to be in good agreement with published experimental studies. Afterwards, the effects of the inclination and length of breakwater as well as distance between two breakwaters are evaluated on damping ratio of breakwater.

  8. Oxygen dynamics during submergence in the halophytic stem succulent Halosarcia pergranulata

    DEFF Research Database (Denmark)

    Pedersen, Ole; Vos, Harrie; Colmer, Timothy David

    2006-01-01

    This study elucidated O2 dynamics in shoots and roots of submerged Halosarcia pergranulata (Salicornioideae), a perennial halophytic stem succulent that grows on flood-prone mudflats of salt lakes. Oxygen within shoots and roots was measured using microelectrodes, for plants when waterlogged...... the roots, at least during the first several hours (the time period measured) after submergence or when light periods followed darkness. The influence of light on tissue O2 dynamics was confirmed in an experiment on a submerged plant in a salt lake in south-western Australia. In the late afternoon, partial...

  9. Impinging jet atomization at elevated and supercritical ambient conditions

    Science.gov (United States)

    Shen, Yunbiao

    This thesis presents an experimental study of the atomization of two impinging jets at elevated pressure and temperature conditions up to the supercritical ambient states. This problem is of central importance to the modeling of the mixing and combustion processes in modern liquid propellant rocket engines. Liquid nitrogen, as well as water, ethanol and 59% water glycerol solution are used as the test fluids. Sprays of various fluid properties are injected into the specially designed test chambers at temperatures as high as 600 K and elevated pressures up to the critical pressure of nitrogen. The thickness of a spreading sheet formed by the impingement of low speed jets is measured by real time interferometry. The results verified previous theoretical prediction. Double pulse, two reference beam holography is improved and applied in the droplet size and velocity measurements. Experiments indicate that in elevated but subcritical ambient conditions, the increase of ambient temperature will generally improve the fineness and uniformity of the spray. However, increase of the ambient pressure initially deteriorates the atomization quality. Further increase in the pressure improves the atomization quality. At supercritical ambient conditions, droplet formation is no longer the ultimate reason of spray atomization. The mechanism of spray mixing is found to be 'diffusion controlled' rather than 'evaporation controlled' as in subcritical conditions. Explanations of the experimental results are provided through the temperature and pressure dependence of the aerodynamic disturbances on the spray surface, heat and mass transport, aerodynamic drag and surface tension. The effects of jet diameter, impingement angle and jet velocity are also investigated in both subcritical and supercritical conditions. The atomization quality is found to be generally improved by smaller jet diameter, larger impingement angle and higher jet velocity.

  10. Jet physics at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    S. Seidel

    2002-05-29

    Recent analyses by the CDF and D0 Collaborations of jet data produced in p{bar p} collisions at the Fermilab Tevatron Collider are presented. These include new studies of the inclusive jet production cross section, a measurement of the strong coupling constant, the first measurement of subjet multiplicity of quark and gluon jets, examination of ratios of multijet cross sections and their implications for choice of renormalization scale, and a study of charged jet evolution and energy flow in the underlying event. The results are compared to theoretical predictions.

  11. Jet Physics at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bhatti, Anwar; Lincoln, Don

    2010-02-01

    Jets have been used to verify the theory of quantum chromodynamics (QCD), measure the structure of the proton and to search for the physics beyond the Standard Model. In this article, we review the current status of jet physics at the Tevatron, a {radical}s = 1.96 TeV p{bar p} collider at the Fermi National Accelerator Laboratory. We report on recent measurements of the inclusive jet production cross section and the results of searches for physics beyond the Standard Model using jets. Dijet production measurements are also reported.

  12. Jet Suppression Measured in ATLAS

    CERN Document Server

    Citron, Zvi Hirsh; The ATLAS collaboration

    2015-01-01

    In relativistic heavy ion collisions, a hot medium with a high density of unscreened color charges is produced, and jets propagating through this medium are known to suffer energy loss. This results in a lower yield of jets emerging from the medium than expected in the absence of medium effects, and thus modifications of the jet yield are directly sensitive to the energy loss mechanism. Furthermore, jets with different flavor content are expected to be affected by the medium in different ways. Parton showers initiated by quarks tend to have fewer fragments carrying a larger fraction of the total jet energy than those resulting from gluons. In this talk, the latest ATLAS results on single jet suppression will be presented. Measurements of the nuclear modification factor, RAA, for fully reconstructed jets are shown. The rapidity dependence of jet suppression is discussed, which is sensitive to the relative energy loss between quark and gluon jets. New measurements of single hadron suppression out to pT~150 GeV ...

  13. Fundamental study on gene transfer utilizing magnetic force and jet injector

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T.; Nakagami, H.; Akiyama, Y.; Nishjima, S. [Osaka University, Osaka (Japan)

    2017-03-15

    Recently, DNA vaccination is attracting attentions as a new therapeutic method for lifestyle diseases and autoimmune diseases. However, its clinical applications are limited because a safe and efficient gene transfer method has not been established yet. In this study, a new method of gene transfer was proposed which utilizes the jet injection and the magnetic transfection. The jet injection is a method to inject medical liquid by momentary high pressure without needle. The injected liquid diffuses in the bio tissue and the endocytosis is considered to be improved by the diffusion. The magnetic transfection is a method to deliver the conjugates of plasmid DNA and magnetic particles to the desired site by external magnetic field. It is expected that jet injection of the conjugates causes slight membrane disruptions and the traction of the conjugates by magnetic field induces the efficient gene transfer. In conclusion, the possibility of improvement of the gene expression by the combination of jet injection and magnetic transfection was confirmed.

  14. Effects of submergence on growth and survival of saplings of three wetland trees differing in adaptive mechanisms for flood tolerance

    Directory of Open Access Journals (Sweden)

    Fumiko Iwanaga

    2015-04-01

    Full Text Available Aim of study: Withstanding total submergence and reaeration following submergence is essential for the survival and establishment of wetland species. We focused on “LOES–low oxygen escape syndrome” and “LOQS–low oxygen quiescence syndrome” and compared tolerances to total submergence among wetland woody species differing in morphological adaptation to soil flooding. Area of study, materials and methods: This study examined the survival of 2-year-old saplings of Taxodium distichum and Metasequioia glyptostroboides (LOQS species, and Alnus japonica (LOES species, during and after total submergence. Saplings were completely submerged, then de-submerged to determine trends in survival and growth Main results: The M. glyptostroboides and A. japonica saplings could not survive prolonged submergence for more than 8 weeks, whereas saplings of T. distichum survived for over 2 years. Submerged saplings of all species showed no significant growth or modifications in morphology and anatomy under water, such as shoot elongation, adventitious root formation, and/or aerenchyma development. All T. distichum saplings that were de-submerged in the second year had the same pattern of shoot growth regardless of differences in timing and seasonality of de-submergence. Wood formation in T. distichum saplings ceased during submergence and resumed after de-submergence in spring and summer, but not in autumn. Research highlights: T. distichum saplings, which survived longer submergence periods than A. japonica and M. glyptostroboides, had physiological characteristics, such as suspension of growth and metabolism, which allowed survival of protracted total submergence (at least 2 years when saplings were immersed during the dormant stage before leaf flushing.

  15. Electrokinetic Power Generation from Liquid Water Microjets

    Energy Technology Data Exchange (ETDEWEB)

    Duffin, Andrew M.; Saykally, Richard J.

    2008-02-15

    Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

  16. The equation of state of liquid Flibe

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang M.; Schrock, V.E.; Peterson, P.F.

    1991-08-16

    Flibe (Li{sub 2}BeF{sub 4}) is a candidate material for the liquid blanket in the HYLIFE-2 fusion reactor. The thermodynamic properties of the material are important for the study of thermohydraulic behavior of the concept design, including the compressible analysis of the blanket isochoric heating problem and resulting jet breakup. The equation of state provides the relationship between all the thermodynamic properties. Previously, a soft sphere model of liquid equation of state was used for describing a number of liquid metals. In this paper we have fitted the available experimental data for liquid Flibe with a modified soft sphere model. 5 refs.

  17. Instability of low viscosity elliptic jets with varying aspect ratio

    Science.gov (United States)

    Kulkarni, Varun

    2011-11-01

    In this work an analytical description of capillary instability of liquid elliptic jets with varying aspect ratio is presented. Linear stability analysis in the long wave approximation with negligible gravitational effects is employed. Elliptic cylindrical coordinate system is used and perturbation velocity potential substituted in the Laplace equation to yield Mathieu and Modified Mathieu differential equations. The dispersion relation for elliptical orifices of any aspect ratio is derived and validated for axisymmetric disturbances with m = 0, in the limit of aspect ratio, μ = 1 , i.e. the case of a circular jet. As Mathieu functions and Modified Mathieu function solutions converge to Bessel's functions in this limit the Rayleigh-Plateau instability criterion is met. Also, stability of solutions corresponding to asymmetric disturbances for the kink mode, m = 1 and flute modes corresponding to m >= 2 is discussed. Experimental data from earlier works is used to compare observations made for elliptical orifices with μ ≠ 1 . This novel approach aims at generalizing the results pertaining to cylindrical jets with circular cross section leading to better understanding of breakup in liquid jets of various geometries.

  18. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, Ramj; Keppens, R.

    2011-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on

  19. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2010-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on

  20. Laser-induced micro-jetting from armored droplets

    KAUST Repository

    Marston, J. O.

    2015-06-23

    We present findings from an experimental study of laser-induced cavitation within a liquid drop coated with a granular material, commonly referred to as “armored droplets” or “liquid marbles.” The cavitation event follows the formation of plasma after a nanosecond laser pulse. Using ultra-high-speed imaging up to 320,610 fps, we investigate the extremely rapid dynamics following the cavitation, which manifests itself in the form of a plethora of micro-jets emanating simultaneously from the spaces between particles on the surface of the drop. These fine jets break up into droplets with a relatively narrow diameter range, on the order of 10 μm. © 2015, Springer-Verlag Berlin Heidelberg.

  1. Energy balance in JET

    Directory of Open Access Journals (Sweden)

    G.F. Matthews

    2017-08-01

    Full Text Available In this paper we discuss results from the study of the energy balance in JET based on calculated heating energies, radiated energy from bolometry and tile calorimetry. Recent data enables us to be more confident in the numbers used and to exclude certain possibilities but the overall energy imbalance which typically amounts to 25% of total input remains unexplained. This shows that caution is required in interpreting fractional radiated powers which are commonly used to measure the effectiveness of impurity seeded scenarios at reducing divertor heat load.

  2. Oscillation of the velvet worm slime jet by passive hydrodynamic instability

    OpenAIRE

    Concha, Andrés; Mellado, Paula; Morera-Brenes, Bernal; Sampaio Costa, Cristiano; Mahadevan, L,; Monge-Nájera, Julián

    2015-01-01

    The rapid squirt of a proteinaceous slime jet endows velvet worms (Onychophora) with a unique mechanism for defence from predators and for capturing prey by entangling them in a disordered web that immobilizes their target. However, to date, neither qualitative nor quantitative descriptions have been provided for this unique adaptation. Here we investigate the fast oscillatory motion of the oral papillae and the exiting liquid jet that oscillates with frequencies f~30–60 Hz. Using anatomical ...

  3. Outer Continental Shelf Submerged Lands Act Boundary - Atlantic Region NAD83

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains the Submerged Lands Act (SLA) boundary line (also known as State Seaward Boundary (SSB), or Fed State Boundary) in ESRI shapefile formats for...

  4. The Development of a Composite Consumable Insert for Submerged ARC Welding

    National Research Council Canada - National Science Library

    1980-01-01

    .... When the submerged arc process was utilized to weld the butt joint in large flat plate structures, the repositioning of the plate for welding of the reverse side was a costly time consuming procedure...

  5. Meta Modelling of Submerged-Arc Welding Design based on Fuzzy Algorithm

    Science.gov (United States)

    Song, Chang-Yong; Park, Jonghwan; Goh, Dugab; Park, Woo-Chang; Lee, Chang-Ha; Kim, Mun Yong; Kang, Jinseo

    2017-12-01

    Fuzzy algorithm based meta-model is proposed for approximating submerged-arc weld design factors such as weld speed and weld output. Orthogonal array design based on the submerged-arc weld numerical analysis is applied to the proposed approach. The nonlinear finite element analysis is carried out to simulate the submerged-arc weld numerical analysis using thermo-mechanical and temperature-dependent material properties for general mild steel. The proposed meta-model based on fuzzy algorithm design is generated with triangle membership functions and fuzzy if-then rules using training data obtained from the Taguchi orthogonal array design data. The aim of proposed approach is to develop a fuzzy meta-model to effectively approximate the optimized submerged-arc weld factors. To validate the meta-model, the results obtained from the fuzzy meta-model are compared to the best cases from the Taguchi orthogonal array.

  6. Large-Scale Submerged Aquatic Vegetation Restoration in Chesapeake Bay: Status Report, 2003-2006

    National Research Council Canada - National Science Library

    Shafer, Deborah J; Bergstrom, Peter

    2008-01-01

    In 2003, the U.S. Army Engineer Research and Development Center (ERDC) and the National Oceanic and Atmospheric Administration Chesapeake Bay Office began a comprehensive research effort to restore submerged aquatic vegetation (SAV...

  7. Flow Velocity and Morphology of a Submerged Patch of the Aquatic Species

    NARCIS (Netherlands)

    Cornacchia, L.; Licci, S.; van de Koppel, J.; van der Wal, D.; Wharton, G.; Puijalon, S.; Bouma, T.J.

    2016-01-01

    The interaction between macrophytes and hydrodynamic conditions is animportant feature in many aquatic ecosystems. Submerged macrophytes can formmonospecific patches that interact with the flow and alter current velocity; withinthe same vegetation patch, plants are exposed to different levels of

  8. Uncalibrated EAARL-B Submerged Topography--Fort Lauderdale, Florida, 2014 (GEOID12A)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Binary point-cloud data of a portion of the submerged environs of Fort Lauderdale, Florida, were produced from remotely sensed, geographically referenced elevation...

  9. EAARL-B Submerged Topography - Saint Croix, U.S. Virgin Islands, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — ASCII XYZ point cloud data for a portion of the submerged environs of Saint Croix, U.S. Virgin Islands, was produced from remotely sensed, geographically referenced...

  10. EAARL-B Submerged Topography—Crocker Reef, Florida, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — ASCII XYZ point cloud data for a portion of the submerged environs of Crocker Reef, Florida, were produced from remotely sensed, geographically referenced elevation...

  11. Calibrated EAARL-B Submerged Topography--Fort Lauderdale, Florida, 2014 (GEOID12A)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Binary point-cloud data of a portion of the submerged environs of Fort Lauderdale, Florida, were produced from remotely sensed, geographically referenced elevation...

  12. Environmental Assessment: Submerged Aquatic Plant Management of Banks Lake, Banks Lake NWR, Lakeland, Georgia

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Environmental Assessment is an analysis of five alternatives developed to address themanagement of the submerged aquatic plants of Banks Lake on Banks Lake...

  13. Satellite remote sensing of submerged aquatic vegetation distribution and status in the Currituck Sound, NC.

    Science.gov (United States)

    2012-11-01

    Submerged Aquatic Vegetation (SAV) is an important component in any estuarine ecosystem. As such, it is regulated by federal and state agencies as a jurisdictional resource, where impacts to SAV are compensated through mitigation. Historically, tradi...

  14. Root transcript profiling of two Rorippa (brassicaceae) species reveals gene clusters associated with extreme submergence tolerance.

    NARCIS (Netherlands)

    Sasidharan, R.; Mustroph, A.; Boonman, A.; Akman, M.; Ammerlaan, A.M.H.; Breit, T.M.; Schranz, M.E.; Voesenek, L.A.C.J.; Tienderen, van P.H.

    2013-01-01

    Complete submergence represses photosynthesis and aerobic respiration, causing rapid mortality in most terrestrial plants. However, some plants have evolved traits allowing them to survive prolonged flooding, such as species of the genus Rorippa, close relatives of Arabidopsis (Arabidopsis

  15. Root transcript profiling of two Rorippa species reveals gene clusters associated with extreme submergence tolerance

    NARCIS (Netherlands)

    Sasidharan, R.; Mustroph, A.; Boonman, A.; Akman, M.; Ammerlaan, A.M.H.; Breit, T.M.; Schranz, M.E.; Voesenek, L.A.C.J.; van Tienderen, P.H.

    2013-01-01

    Complete submergence represses photosynthesis and aerobic respiration, causing rapid mortality in most terrestrial plants. However, some plants have evolved traits allowing them to survive prolonged flooding, such as species of the genus Rorippa, close relatives of Arabidopsis (Arabidopsis

  16. Swan foraging shapes spatial distribution of two submerged plants, favouring the preferred prey species

    NARCIS (Netherlands)

    Sandsten, H.; Klaassen, M.R.J.

    2008-01-01

    Compared to terrestrial environments, grazing intensity on belowground plant parts may be particularly strong in aquatic environments, which may have great effects on plant-community structure. We observed that the submerged macrophyte, Potamogeton pectinatus, which mainly reproduces with tubers,

  17. EAARL-B Submerged Topography—Saint Thomas, U.S. Virgin Islands, 2014

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — ASCII XYZ point cloud data for a portion of the submerged environs of Saint Thomas, U.S. Virgin Islands, was produced from remotely sensed, geographically referenced...

  18. Uncalibrated EAARL-B Submerged Topography--Fort Lauderdale, Florida, 2014 (WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Binary point-cloud data of a portion of the submerged environs of Fort Lauderdale, Florida, were produced from remotely sensed, geographically referenced elevation...

  19. Calibrated EAARL-B Submerged Topography--Fort Lauderdale, Florida, 2014 (WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Binary point-cloud data of a portion of the submerged environs of Fort Lauderdale, Florida, were produced from remotely sensed, geographically referenced elevation...

  20. Outer Continental Shelf Submerged Lands Act Boundary - Pacific Region - West Coast NAD83

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains the Submerged Lands Act (SLA)boundary line (also known as the State Seaward Boundary (SSB) and Fed State Boundary) for the BOEM Pacific Region...

  1. Process Modeling and Optimization of a Submerged Arc Furnace for Phosphorus Production

    NARCIS (Netherlands)

    Scheepers, E.; Yang, Y.; Adema, A.T.; Boom, R.; Reuter, M.A.

    2010-01-01

    This article presents a process model of a phosphorus-producing, submerged arc furnace. The model successfully incorporates accurate, multifield thermodynamic, kinetic, and industrial data with computational flow dynamic calculations and thus further unifies the sciences of kinetics and equilibrium

  2. EAARL-B Submerged Topography - Saint Croix and Saint Thomas, U.S. Virgin Islands, 2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Binary point-cloud data for part of the submerged environs of Saint Croix and Saint Thomas, U.S. Virgin Islands, were produced from remotely sensed, geographically...

  3. Outer Continental Shelf Submerged Lands Act Boundary - Alaska Region NAD83

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains the Submerged Lands Act (SLA) boundary (also known as State Seaward Boundary (SSB), or Fed State Boundary) in ESRI shapefile format for the...

  4. Tolerance of combined submergence and salinity in the halophytic stem-succulent Tecticornia pergranulata

    DEFF Research Database (Denmark)

    Colmer, T D; Vos, H; Pedersen, Ole

    2009-01-01

    in waters of high salinity. A 'quiescence response', i.e. no shoot growth, would conserve carbohydrates, but tissue sugars still declined with time. A low K(+) : Na(+) ratio, typical for tissues of succulent halophytes, was tolerated even during prolonged submergence, as evidenced by maintenance......BACKGROUND AND AIMS: Habitats occupied by many halophytes are not only saline, but are also prone to flooding. Few studies have evaluated submergence tolerance in halophytes. METHODS: Responses to submergence, at a range of salinity levels, were studied for the halophytic stem-succulent Tecticornia...... pergranulata subsp. pergranulata (syn. Halosarcia pergranulata subsp. pergranulata). Growth and total sugars in succulent stems were assessed as a function of time after submergence. Underwater net photosynthesis, dark respiration, total sugars, glycinebetaine, Na(+), Cl(-) and K(+), in succulent stems, were...

  5. Dynamic Response Analysis of Cable of Submerged Floating Tunnel under Hydrodynamic Force and Earthquake

    Directory of Open Access Journals (Sweden)

    Zhiwen Wu

    2017-01-01

    Full Text Available A simplified analysis model of cable for submerged floating tunnel subjected to parametrically excited vibrations in the ocean environment is proposed in this investigation. The equation of motion of the cable is obtained by a mathematical method utilizing the Euler beam theory and the Galerkin method. The hydrodynamic force induced by earthquake excitations is formulated to simulate real seaquake conditions. The random earthquake excitation in the time domain is formulated by the stochastic phase spectrum method. An analytical model for analyzing the cable for submerged floating tunnel subjected to combined hydrodynamic forces and earthquake excitations is then developed. The sensitivity of key parameters including the hydrodynamic, earthquake, and structural parameters on the dynamic response of the cable is investigated and discussed. The present model enables a preliminary examination of the hydrodynamic and seismic behavior of cable for submerged floating tunnel and can provide valuable recommendations for use in design and operation of anchor systems for submerged floating tunnel.

  6. EAARL-B submerged topography: Barnegat Bay, New Jersey, pre-Hurricane Sandy, 2012

    Science.gov (United States)

    Wright, C. Wayne; Troche, Rodolfo J.; Klipp, Emily S.; Kranenburg, Christine J.; Fredericks, Alexandra M.; Nagle, David B.

    2014-01-01

    These remotely sensed, geographically referenced elevation measurements of lidar-derived submerged topography datasets were produced by the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

  7. Metal accumulation by submerged macrophytes in eutrophic lakes at the watershed scale.

    Science.gov (United States)

    Xing, Wei; Wu, Haoping; Hao, Beibei; Liu, Guihua

    2013-10-01

    Metal concentrations (Al, Ba, Ca, K, Li, Mg, Na, Se, Sr and Ti) in submerged macrophytes and corresponding water and sediments were studied in 24 eutrophic lakes along the middle and lower reaches of the Yangtze River (China). Results showed that these eutrophic lakes have high metal concentrations in both water and sediments because of human activities. Average concentrations of Al and Na in tissues of submerged macrophytes were very high in sampled eutrophic lakes. By comparison, Ceratophyllum demersum and Najas marina accumulated more metals (e.g. Ba, Ca, K, Mg, Na, Sr and Ti). Strong positive correlations were found between metal concentrations in tissues of submerged macrophytes, probably because of co-accumulation of metals. The concentrations of Li, Mg, Na and Sr in tissues of submerged macrophytes significantly correlated with their corresponding water values, but not sediment values.

  8. Outer Continental Shelf Submerged Lands Act Boundary - Gulf of Mexico Region NAD27

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set contains the Submerged Lands Act (SLA) boundary line (also known as State Seaward Boundary (SSB), or Fed State Boundary)in ESRI shapefile formats for...

  9. Suitability of seagrasses and submerged aquatic vegetation as indicators of eutrophication

    Science.gov (United States)

    Rooted submerged aquatic vegetation (SAV) encompasses a large diversity of species that range from obligate halophytes such as, seagrasses, to euryhaline species and freshwater obligates. All seagrass and SAV provide key biological functions within the enclosed bays, estuaries, a...

  10. Characterization of Horizontally-Issuing Reacting Buoyant Jets

    Science.gov (United States)

    2011-03-01

    mixing characteristics of a vertically issuing helium jet through the implementation of stroboscopic Schlieren imaging and Doppler velocimetry. One of...instabilities, a rainbow schlieren deflectometry technique was implemented in conjunction with a high speed imaging system. Ultimately, the flame structure and...stored in liquid form. The propane, therefore, must be vaporized before being used for experimental purposes. In order to vaporize the propane Zimmer

  11. EAARL Submerged Topography - U.S. Virgin Islands 2003

    Science.gov (United States)

    Nayegandhi, Amar; Brock, John C.; Wright, C. Wayne; Stevens, Sara; Yates, Xan; Bonisteel, Jamie M.

    2008-01-01

    These remotely sensed, geographically referenced elevation measurements of Lidar-derived submerged topography were produced as a collaborative effort between the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC), St. Petersburg, FL; the National Park Service (NPS), South Florida-Caribbean Network, Miami, FL; and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA. This project provides highly detailed and accurate bathymetric datasets of a portion of the U.S. Virgin Islands, acquired on April 21, 23, and 30, May 2, and June 14 and 17, 2003. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative airborne Lidar instrument originally developed at the NASA Wallops Flight Facility, and known as the Experimental Advanced Airborne Research Lidar (EAARL), was used during data acquisition. The EAARL system is a raster-scanning, waveform-resolving, green-wavelength (532-nanometer) Lidar designed to map near-shore bathymetry, topography, and vegetation structure simultaneously. The EAARL sensor suite includes the raster-scanning, water-penetrating full-waveform adaptive Lidar, a down-looking red-green-blue (RGB) digital camera, a high-resolution multi-spectral color infrared (CIR) camera, two precision dual-frequency kinematic carrier-phase GPS receivers, and an integrated miniature digital inertial measurement unit, which provide for submeter georeferencing of each laser sample. The nominal EAARL platform is a twin-engine Cessna 310 aircraft, but the instrument may be deployed on a range of light aircraft. A single pilot, a Lidar operator, and a data analyst constitute the crew for most survey operations. This sensor has the potential to make significant contributions in measuring sub-aerial and submarine coastal topography within cross-environmental surveys. Elevation measurements were collected over the survey area using the EAARL system, and

  12. Critical assessment of jet erosion test methodologies for cohesive soil and sediment

    Science.gov (United States)

    Karamigolbaghi, Maliheh; Ghaneeizad, Seyed Mohammad; Atkinson, Joseph F.; Bennett, Sean J.; Wells, Robert R.

    2017-10-01

    The submerged Jet Erosion Test (JET) is a commonly used technique to assess the erodibility of cohesive soil. Employing a linear excess shear stress equation and impinging jet theory, simple numerical methods have been developed to analyze data collected using a JET to determine the critical shear stress and erodibility coefficient of soil. These include the Blaisdell, Iterative, and Scour Depth Methods, and all have been organized into easy to use spreadsheet routines. The analytical framework of the JET and its associated methods, however, are based on many assumptions that may not be satisfied in field and laboratory settings. The main objective of this study is to critically assess this analytical framework and these methodologies. Part of this assessment is to include the effect of flow confinement on the JET. The possible relationship between the derived erodibility coefficient and critical shear stress, a practical tool in soil erosion assessment, is examined, and a review of the deficiencies in the JET methodology also is presented. Using a large database of JET results from the United States and data from literature, it is shown that each method can generate an acceptable curve fit through the scour depth measurements as a function of time. The analysis shows, however, that the Scour Depth and Iterative Methods may result in physically unrealistic values for the erosion parameters. The effect of flow confinement of the impinging jet increases the derived critical shear stress and decreases the erodibility coefficient by a factor of 2.4 relative to unconfined flow assumption. For a given critical shear stress, the length of time over which scour depth data are collected also affects the calculation of erosion parameters. In general, there is a lack of consensus relating the derived soil erodibility coefficient to the derived critical shear stress. Although empirical relationships are statistically significant, the calculated erodibility coefficient for a

  13. Anatomy of floating and submerged leaves of heterophyllous plant of Nymphaea candida L.

    OpenAIRE

    E.N. Klimenko

    2014-01-01

    The data on anatomy of floating and submerged leaves of heterophyllous aquatic plant Nymphaea candida L. are presented. Anatomy of floating leaves is shown to be different from that of submerged leaves: the absence of stomata, asterosclereids, and differentiated parenchyma, as well as by reduce intercellular volume and leaf width. Common patterns of leaf structure plasticity of aquatic heterophyllous plants in dependence on the environment are discussed.

  14. Aquatic adventitious root development in partially and completely submerged wetland plants Cotula coronopifolia and Meionectes brownii.

    Science.gov (United States)

    Rich, Sarah Meghan; Ludwig, Martha; Colmer, Timothy David

    2012-07-01

    A common response of wetland plants to flooding is the formation of aquatic adventitious roots. Observations of aquatic root growth are widespread; however, controlled studies of aquatic roots of terrestrial herbaceous species are scarce. Submergence tolerance and aquatic root growth and physiology were evaluated in two herbaceous, perennial wetland species Cotula coronopifolia and Meionectes brownii. Plants were raised in large pots with 'sediment' roots in nutrient solution and then placed into individual tanks and shoots were left in air or submerged (completely or partially). The effects on growth of aquatic root removal, and of light availability to submerged plant organs, were evaluated. Responses of aquatic root porosity, chlorophyll and underwater photosynthesis, were studied. Both species tolerated 4 weeks of complete or partial submergence. Extensive, photosynthetically active, aquatic adventitious roots grew from submerged stems and contributed up to 90 % of the total root dry mass. When aquatic roots were pruned, completely submerged plants grew less and had lower stem and leaf chlorophyll a, as compared with controls with intact roots. Roots exposed to the lowest PAR (daily mean 4.7 ± 2.4 µmol m(-2) s(-1)) under water contained less chlorophyll, but there was no difference in aquatic root biomass after 4 weeks, regardless of light availability in the water column (high PAR was available to all emergent shoots). Both M. brownii and C. coronopifolia responded to submergence with growth of aquatic adventitious roots, which essentially replaced the existing sediment root system. These aquatic roots contained chlorophyll and were photosynthetically active. Removal of aquatic roots had negative effects on plant growth during partial and complete submergence.

  15. Agenesis of premolar associated with submerged primary molar and a supernumerary premolar: An unusual case report

    Directory of Open Access Journals (Sweden)

    S. V. S. G. Nirmala

    2012-01-01

    Full Text Available The combination of submerged primary molar, agenesis of permanent successor with a supernumerary in the same place is very rare. The purpose of this article is to report a case of submerged mandibular left second primary molar with supernumerary tooth in the same region along with agenesis of second premolar in an 11-year-old girl, its possible etiological factors, and a brief discussion on treatment options.

  16. Parametric and Nonparametric Analysis of LANDSAT TM and MSS Imagery for Detecting Submerged Plant Communities

    Science.gov (United States)

    Ackleson, S. G.; Klemas, V.

    1984-01-01

    The spatial, spectral and radiometric characteristics of LANDSAT TM and MSS imagery for detecting submerged aquatic vegetation are assessed. The problem is approached from two perspectives; purely stochastic or nonparametric in a radiative sense and theoretical in which radiative transfer equations are used to predict upwelling radiance at satellite altitude. The spectral and radiometric aspects of the theoretical approach are addressed with which a submerged plant canopy is distinguished from a surrounding bottom of sand or mud.

  17. Jet-quenching and correlations

    Indian Academy of Sciences (India)

    2015-05-06

    May 6, 2015 ... Abstract. This article reviews recent advances in our understanding of the experimental aspects of jet-quenching and correlations in relativistic heavy-ion collisions at RHIC and LHC. Emphasis is put on correlation measurements, namely jet-like correlations with anisotropic flow subtraction in heavy-ion ...

  18. Magnetic Field Topology in Jets

    Science.gov (United States)

    Gardiner, T. A.; Frank, A.

    2000-01-01

    We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

  19. Associated jet production at HERA

    CERN Document Server

    Bartels, Julius; de Roeck, A; Graudenz, Dirk; Wüsthoff, M

    1996-01-01

    We compare the BFKL prediction for the associated production of forward jets at HERA with fixed-order matrix element calculations taking into account the kinematical cuts imposed by experimental conditions. Comparison with H1 data of the 1993 run favours the BFKL prediction. As a further signal of BFKL dynamics, we propose to look for the azimuthal dependence of the forward jets.

  20. Synthetic Jet Actuator Performance Enhancement

    Science.gov (United States)

    Pikcilingis, Lucia; Housley, Kevin; Whalen, Ed; Amitay, Michael; Rensselaer Polytechnic Institute Collaboration; Boeing Company Collaboration

    2014-11-01

    Over the last 20 years synthetic jets have been studied as a means for aerodynamic flow control. Specifically, synthetic jets provide momentum transfer with zero-net mass flux, which has been proven to be effective for controlling flow fields. A synthetic jet is created by the periodic formation of vortex rings at its orifice due to the periodic motion of a piezoelectric disk(s). The present study seeks to optimize the performance of a synthetic jet actuator by utilizing different geometrical parameters such as disk thickness, orifice width and length, cavity height and cavity diameter, and different input parameters such as voltage and frequency. Experiments were conducted using a synthetic jet apparatus designed for various geometrical parameters utilizing a dual disk configuration. Velocity and temperature measurements were acquired at the center of the synthetic jet orifice using a temperature compensated hotwire and thermocouple probe. The disk displacement was measured at the center of the disk with a laser displacement sensor. It was shown that the synthetic jet actuators are capable of exceeding peak velocities of 200 m/s with a relatively large orifice. Data suggests that jet velocities greater than 200 m/s are attainable.

  1. Jet-quenching and correlations

    Indian Academy of Sciences (India)

    2015-05-06

    May 6, 2015 ... This article reviews recent advances in our understanding of the experimental aspects of jet-quenching and correlations in relativistic heavy-ion collisions at RHIC and LHC. Emphasis is put on correlation measurements, namely jet-like correlations with anisotropic flow subtraction in heavy-ion collisions ...

  2. LHCb; LHCb Jet Reconstruction

    CERN Multimedia

    Augusto, O

    2012-01-01

    The Large Hadron Collider (LHC) is the most powerful particle accelerator in the world. It has been designed to collide proton beams at an energy up to 14 TeV in the center of mass. In 2011, the data taking was done with a center of mass energy of 7 TeV, the instant luminosity has reached values greater than $4 \\times 10^{32} cm^{-2} s^{-1}$ and the integrated luminosity reached the value of 1.02 $fb^{-1}$ on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test pertubative QCD (pQCD). It also provides a way to observe standard model channels and searches for new physics like SUSY. The anti-kt algorithm is a jet reconstruction algorithm that is based on the distance of the particles on the space $\\eta \\times \\phi$ and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the calo...

  3. The Hydrodynamics of Needle-Free Intradermal Jet Injection

    Science.gov (United States)

    Simmons, Jonathan; Marston, Jeremy; Fisher, Paul; Broderick, Kate

    2017-11-01

    Needle-free methods of drug delivery circumvent the drawbacks associated with the use of hypodermic needles such as needle-stick injuries, needle-phobia, cross contamination and disposal. Furthermore, pioneering DNA-based vaccines that aim to treat cancer and fight infectious diseases, such as HIV, Ebola and Zika, require precise deposition into the skin to target the immune response producing cells found only in the epidermis and dermis. Intradermal (ID) delivery can be achieved using a needle and the Mantoux technique but this requires a highly skilled technician and so extensive use of DNA vaccines calls for an alternative method of delivery. One option is jet injection which has been employed in mass vaccination programs for intramuscular or subcutaneous delivery and is used by some diabetic patients to inject insulin. In this talk I will present results from our ongoing ex-vivo experimental study into ID jet injection. Ultra-high-speed imaging is used to visualize the process of the jet exiting the nozzle and striking excised skin. A skin bleb grows as liquid is deposited within the skin. I will discuss how the control parameters, such as the rheological profile of the liquid and the stand-off distance, influence the volume of liquid successfully delivered intradermally.

  4. Biodegradation of toxic chemicals by Pleurotus eryngii in submerged fermentation and solid-state fermentation.

    Science.gov (United States)

    Chang, Bea-Ven; Chang, Yi-Ming

    2016-04-01

    The toxic chemicals bisphenol A (BPA), bisphenol F (BPF), nonylphenol (NP), and tetrabromobisphenol A (TBBPA) are endocrine-disrupting chemicals that have consequently drawn much concern regarding their effect on the environment. The objectives of this study were to investigate the degradation of BPA, BPF, NP, and TBBPA by enzymes from Pleurotus eryngii in submerged fermentation (SmF) and solid-state fermentation (SSF), and also to assess the removal of toxic chemicals in spent mushroom compost (SMC). BPA and BPF were analyzed by high-performance liquid chromatography; NP and TBBPA were analyzed by gas chromatography. NP degradation was enhanced by adding CuSO4 (1 mM), MnSO4 (0.5 mM), gallic acid (1 mM), tartaric acid (20 mM), citric acid (20 mM), guaiacol (1 mM), or 2,2'-azino-bis- (3-ethylbenzothiazoline-6-sulfonic acid; 1 mM), with the last yielding a higher NP degradation rate than the other additives from SmF. The optimal conditions for enzyme activity from SSF were a sawdust/wheat bran ratio of 1:4 and a moisture content of 5 mL/g. The enzyme activities were higher with sawdust/wheat bran than with sawdust/rice bran. The optimal conditions for the extraction of enzyme from SMC required using sodium acetate buffer (pH 5.0, solid/solution ratio 1:5), and extraction over 3 hours. The removal rates of toxic chemicals by P. eryngii, in descending order of magnitude, were SSF > SmF > SMC. The removal rates were BPF > BPA > NP > TBBPA. Copyright © 2014. Published by Elsevier B.V.

  5. 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

  6. Double-focusing mixing jet for XFEL study of chemical kinetics.

    Science.gov (United States)

    Wang, Dingjie; Weierstall, Uwe; Pollack, Lois; Spence, John

    2014-11-01

    Several liquid sample injection methods have been developed to satisfy the requirements for serial femtosecond X-ray nanocrystallography, which enables radiation-damage-free determination of molecular structure at room temperature. Time-resolved nanocrystallography would combine structure analysis with chemical kinetics by determining the structures of the transient states and chemical kinetic mechanisms simultaneously. A windowless liquid mixing jet device has been designed for this purpose. It achieves fast uniform mixing of substrates and enzymes in the jet within 250 µs, with an adjustable delay between mixing and probing by the X-ray free-electron laser beam of up to 1 s for each frame of a `movie'. The principle of the liquid mixing jet device is illustrated using numerical simulation, and experimental results are presented using a fluorescent dye.

  7. Dynamics of swirling jet flows

    Energy Technology Data Exchange (ETDEWEB)

    Ivanic, T.; Foucault, E.; Pecheux, J. [Laboratoire d' Etudes Aerodynamiques (L.E.A. CNRS UMR 6609), Boulevard Marie et Pierre Curie, Teleport 2, BP 30179, 86960, Futuroscope Chasseneuil Cedex (France)

    2003-10-01

    Experimental investigations of near-field structure of coaxial flows are presented for four different configurations: coaxial jets without rotation (reference case), outer flow rotating only (OFRO), inner-jet rotating only (IJRO) and corotating jets (CRJ). The investigations are performed in a cylindrical water tunnel, with an independent rotation of two coaxial flows. Laser tomography is used to document the flow field, and photographs are shown for different configurations. Time mean velocity profiles obtained by PIV, with and without swirl, are also presented. The dynamics of the swirling jets in the initial region (i.e. near the exit of the jets) is described. The effects of azimuthal velocity and axial velocity ratio variations on flow dynamics are examined. The appearance and growth of the first instabilities are presented and compared with some theoretical results, as is the influence of the rotation (inner or outer) on the dominating structures. (orig.)

  8. Hydrodynamic Stability Analysis of Multi-jet Effects in Swirling Jet Combustors

    Science.gov (United States)

    Emerson, Benjamin; Lieuwen, Tim

    2016-11-01

    Many practical combustion devices use multiple swirling jets to stabilize flames. However, much of the understanding of swirling jet dynamics has been generated from experimental and computational studies of single reacting, swirling jets. A smaller body of literature has begun to explore the effects of multi-jet systems and the role of jet-jet interactions on the macro-system dynamics. This work uses local temporal and spatio-temporal stability analyses to isolate the hydrodynamic interactions of multiple reacting, swirling jets, characterized by jet diameter, D, and spacing, L. The results first identify the familiar helical modes in the single jet. Comparison to the multi-jet configuration reveals these same familiar modes simultaneously oscillating in each of the jets. Jet-jet interaction is mostly limited to a spatial synchronization of each jet's oscillations at the jet spacing values analyzed here (L/D =3.5). The presence of multiple jets vs a single jet has little influence on the temporal and absolute growth rates. The biggest difference between the single and multi-jet configurations is the presence of nearly degenerate pairs of hydrodynamic modes in the multi-jet case, with one mode dominated by oscillations in the inner jet, and the other in the outer jets. The close similarity between the single and multi-jet hydrodynamics lends insight into experiments from our group.

  9. Growth rate, protein:RNA ratio and stoichiometric homeostasis of submerged macrophytes under eutrophication stress

    Directory of Open Access Journals (Sweden)

    Xing W.

    2016-01-01

    Full Text Available Growth rate hypothesis (GRH and stoichiometric homeostasis of photoautotrophs have always been questioned. However, little is known about GRH and stoichiometric homeostasis of aquatic plants, especially submerged macrophytes. Therefore, we aim to test the GRH and explore stoichiometric homeostasis of four freshwater submerged macrophytes under eutrophication stress. At the single species level and the multi-species level, N:P ratios of Potamogeton maackianus, Myriophyllum spicatum, Vallisneria natans and Ceratophyllum demersum had no consistent trends with growth rates. However, protein:RNA ratios of P. maackianus, M. spicatum and V. natans all correlated negatively with growth rates, demonstrating GRH can apply to freshwater submerged macrophytes, even though they are threatening by eutrophication stress. Protein:RNA ratios positively correlated with N:P ratios in culture media and tissues in submerged macrophytes except in P. maackianus (30d, suggesting effects of varying N:P ratios in culture media on protein:RNA ratios are basically in concert with tissue N:P ratios under short-time eutrophication stress. Stoichiometric homeostasis coefficients (HN:P indicated submerged macrophytes have weak homeostasis. Stoichiometric homeostasis of V. natans was stronger than those of P. maackianus, M. spicatum and C. demersum. The differences in GRH and homeostasis of the four submerged macrophytes may be due to species traits.

  10. Structural and Acoustic Responses of a Submerged Stiffened Conical Shell

    Directory of Open Access Journals (Sweden)

    Meixia Chen

    2014-01-01

    Full Text Available This paper studies the vibrational behavior and far-field sound radiation of a submerged stiffened conical shell at low frequencies. The solution for the dynamic response of the conical shell is presented in the form of a power series. A smeared approach is used to model the ring stiffeners. Fluid loading is taken into account by dividing the conical shell into narrow strips which are considered to be local cylindrical shells. The far-field sound pressure is solved by the Element Radiation Superposition Method. Excitations in two directions are considered to simulate the loading on the surface of the conical shell. These excitations are applied along the generator and normal to the surface of the conical shell. The contributions from the individual circumferential modes on the structural responses of the conical shell are studied. The effects of the external fluid loading and stiffeners are discussed. The results from the analytical models are validated by numerical results from a fully coupled finite element/boundary element model.

  11. [Submerged cultivation and chemical composition of Hericium erinaceus mycelium].

    Science.gov (United States)

    Avtonomova, A V; Bakanov, A V; Shuktueva, M I; Vinokurov, V A; Popova, O V; Usov, A I; Krasnopol'skaia, L M

    2012-01-01

    Submerged cultivation of Hericium erinaceus in various media was studied. The yield of the biomass was shown to depend mainly on the carbon source, whereas the content of water soluble polysaccharides depended mainly on the nitrogen source. The optimal medium composition provided the biomass yield of 21-23 g/l in 7 days. The biomass was characterized by the content of total protein, lipids and carbohydrates. In addition, the amino acid composition of the biomass was determined and shown to meet all the requirements of FAO/WHO concerning the amounts of essential amino acids (with exception of tryptophane). Oleinic and linoleic acids were identified as the main components of the fatty acids. Two water soluble polysaccharide fractions differing in solubility in aqueous ethanol were isolated and shown to contain rhamnose, fucose, xylose, glucose and galactose in different proportions. Vitamins B1, B2, B6, PP and E, ergosterol and coenzyme Q were also detected in the biomass of H. erinaceus.

  12. Underwater Photosynthesis of Submerged Plants – Recent Advances and Methods

    Science.gov (United States)

    Pedersen, Ole; Colmer, Timothy D.; Sand-Jensen, Kaj

    2013-01-01

    We describe the general background and the recent advances in research on underwater photosynthesis of leaf segments, whole communities, and plant dominated aquatic ecosystems and present contemporary methods tailor made to quantify photosynthesis and carbon fixation under water. The majority of studies of aquatic photosynthesis have been carried out with detached leaves or thalli and this selectiveness influences the perception of the regulation of aquatic photosynthesis. We thus recommend assessing the influence of inorganic carbon and temperature on natural aquatic communities of variable density in addition to studying detached leaves in the scenarios of rising CO2 and temperature. Moreover, a growing number of researchers are interested in tolerance of terrestrial plants during flooding as torrential rains sometimes result in overland floods that inundate terrestrial plants. We propose to undertake studies to elucidate the importance of leaf acclimation of terrestrial plants to facilitate gas exchange and light utilization under water as these acclimations influence underwater photosynthesis as well as internal aeration of plant tissues during submergence. PMID:23734154

  13. Immunomodulatory properties of Grifola frondosa in submerged culture.

    Science.gov (United States)

    Wu, Ming-Jiuan; Cheng, Tso-Lin; Cheng, Su-Yun; Lian, Tzi-Wei; Wang, Lisu; Chiou, Shu-Yuan

    2006-04-19

    Maitake (Grifola frondosa) is a popular mushroom in Asia for its tasty flavor and immune-stimulating property. The aim of the study is to investigate the innate immunity augmentation effects of different extracts of mycelia and culture filtrate from G. frondosa in submerged cultures. The hot water extract of mycelia showed the strongest cytokine induction effect as a function of its concentration in human whole blood culture. The most potent fractions of hot water extract, Fr. I and II, were mainly composed of polysaccharides with molecular masses of 43-140 and 13-38 kDa, respectively. These fractions (0.025 mg/mL) showed marked activity in enhancing phagocytosis of human polymorphonuclear neutrophils (PMN). In parallel, the expression of CD11b, an early marker of PMN activation, was also up-regulated dose dependently. This result suggested that complement receptor 3 was primed by these fractions. In addition to activation of phagocytes, these bioactive fractions also increased human peripheral blood natural killer cell cytotoxicity. These results imply that the relatively low molecular mass polysaccharides isolated from mycelia of G. frondosa can enhance innate immunity in vitro and therefore may serve as biological response modifiers.

  14. The use of bottle caps as submerged aerated filter medium.

    Science.gov (United States)

    Damasceno de Oliveira, Laurence; Motlagh, Amir Mohaghegh; Goel, Ramesh; de Souza Missagia, Beatriz; Alves de Abreu Filho, Benício; Lautenschlager, Sandro Rogério

    2014-01-01

    In this study, a submerged aerated filter (SAF) using bottle caps as a support medium was evaluated. The system was fed with effluent from an upflow anaerobic sludge blanket system at ETE 2-South wastewater treatment plant, under different volumetric organic load rates (VOLRs). The population of a particular nitrifying microbial community was assessed by fluorescent in situ hybridization with specific oligonucleotide probes. The system showed an average removal of chemical oxygen demand (COD) equal to 76% for VOLRs between 2.6 and 13.6 kg COD m(-3)_media.day(-1). The process of nitrification in conjunction with the removal of organic matter was observed from applying VOLRs lower than 5.5 kg COD m(-3)_media.day(-1) resulting in 78% conversion of NH4(+)-N. As the applied organic load was reduced, an increase in the nitrifying bacteria population was observed compared with total 4'-6-diamidino-2-phenylindole (DAPI) stained cells. Generally, SAF using bottle caps as a biological aerated filter medium treating wastewater from an anaerobic system showed promising removal of chemical oxygen demand (COD) and conversion of NH4(+)-N.

  15. Stainless steel submerged arc weld fusion line toughness

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfield, A.R.; Held, P.R.; Wilkowski, G.M. [Battelle, Columbus, OH (United States)

    1995-04-01

    This effort evaluated the fracture toughness of austenitic steel submerged-arc weld (SAW) fusion lines. The incentive was to explain why cracks grow into the fusion line in many pipe tests conducted with cracks initially centered in SAWS. The concern was that the fusion line may have a lower toughness than the SAW. It was found that the fusion line, Ji. was greater than the SAW toughness but much less than the base metal. Of greater importance may be that the crack growth resistance (JD-R) of the fusion line appeared to reach a steady-state value, while the SAW had a continually increasing JD-R curve. This explains why the cracks eventually turn to the fusion line in the pipe experiments. A method of incorporating these results would be to use the weld metal J-R curve up to the fusion-line steady-state J value. These results may be more important to LBB analyses than the ASME flaw evaluation procedures, since there is more crack growth with through-wall cracks in LBB analyses than for surface cracks in pipe flaw evaluations.

  16. The structure of jet turbulence producing jet noise.

    Science.gov (United States)

    Wooldridge, C. E.; Wooten, D. C.; Amaro, A. J.

    1972-01-01

    Measurements are presented that characterize the structure of the jet in both the core and the surrounding annular mixing region. Experiments were carried out in a 1.5-inch diameter subsonic jet at Mach numbers of 0.3, 0.5, and 0.7. The growth of pressure fluctuations within the core from the jet outlet to the end of the jet core was traced through the examination of spectral results. The spectra in the jet core exhibited a peak whose frequency scaled with the jet velocity and the jet diameter which is related to a characteristic dimension of the mixing process. A digital data reduction program was used to calculate the auto- and cross-correlations of axial velocity fluctuations. In the core the cross-correlations were nearly constant in the space-time plane indicating a traveling pressure wave, while in the annular mixing region the cross-correlations exhibited the usual decay in the space-time plane characteristic of convected turbulence.

  17. Elucidating Jet Energy Loss Using Jets: Prospects from ATLAS

    CERN Document Server

    Grau, N

    2009-01-01

    The details of jet energy loss, as measured at RHIC with single particles and mu lti-particle correlations, are unresolved, and new experimental measurements are necessary in order to shed light on the mechanism and behavior of energy loss. Utilizing the ATLAS electromagnetic and hadronic calorimetry, full jet reconstru ction in a heavy ion environment will be performed over a wide range of $p_T$ an d rapidity. With fully reconstructed jets, new and more sensitive probes are ava ilable to test models of energy loss. In this talk, we present a series of obser vables such as the jet $R_{AA}$, the transverse momentum, $j_T$, spectrum of fra gments, the fragmentation function $D(z)$, jet shapes, and di-jet correlations, that aresensitive to perturbative and non-perturbative energy loss. We also disc uss the current level of sensitivity to expected modifications using several dif ferent jet algorithms, the cone, $k_T$, and anti-$k_T$ algorithms.

  18. The size and shape of gas-focused viscous micro-jets

    Science.gov (United States)

    Ferrera, C.; Ganan-Calvo, A. M.; Montanero, J. M.; Vega, E. J.; Herrada, M. A.

    2011-11-01

    The size and shape of gas-focused viscous micro-jets are analyzed theoretically and experimentally. These micro-jets are shaped by the action of a co-flowing gas stream due to both the pressure drop in the axial direction occurring in front of the discharge orifice, and the tangential viscous stress caused by the difference between the velocities of the gas and jet behind the orifice. The slender approximation is used to describing the shape of the tapering meniscus and the emitted liquid ligament. Assuming that the driving force takes a uniform value over the entire liquid domain, a universal (self-similar) solution of the momentum equation can be obtained. Experiments were conducted to assess the validity of that solution for a wide range of liquid viscosities. A remarkable collapse into a single curve is obtained for of all jet diameters measured beyond the orifice. This result shows that the driving force mentioned above attains a rather homogeneous value at the region where the micro-jet develops. The universal solution also provides satisfactory results in front of the orifice for sufficiently slender liquid meniscus, provided that the ratio capillary-to-orifice distance to orifice diameter takes sufficiently small values. The approach used in this work can also be applied to study other microjet generation means (co-flowing, electrospray, electrospinning...).

  19. The JPL Direct Methanol Liquid-feed PEM Fuel Cell

    Science.gov (United States)

    Halpert, G.; Surampudi, S.

    1994-01-01

    Recently, there has been a breakthrough in fuel cell technology in the Energy Storage Systems Group at the Jet Propulsion Laboratory with the develpment of a direct methanol, liquid-feed, solid polymer electrolyte membrane (PEM) fuel cell... The methanol liquid-feed, solid polymer electrolyte (PEM) design has numerous system level advantages over the gas-feed design. These include:...

  20. Characteristics of bulk liquid undercooling and crystallization ...

    Indian Academy of Sciences (India)

    157–161. c Indian Academy of Sciences. Characteristics of bulk liquid undercooling and crystallization behaviors of jet electrodeposition Ni–W–P alloy. J K YU. ∗. , Y H WANG, G Z XING, Q QIAO, B LIU, Z J CHU, C L LI and F YOU. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University,.

  1. Characteristics of bulk liquid undercooling and crystallization ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 38; Issue 1. Characteristics of bulk liquid undercooling and crystallization behaviors of jet electrodeposition Ni–W–P alloy. J K Yu Y H Wang G Z Xing Q Qiao B Liu Z J Chu C L Li F You. Volume 38 Issue 1 February 2015 pp 157-161 ...

  2. Monodisperse liquid-filled biodegradable microcapsules.

    Science.gov (United States)

    Berkland, Cory; Pollauf, Emily; Varde, Neel; Pack, Daniel W; Kim, Kyekyoon Kevin

    2007-05-01

    Encapsulation of liquids into biodegradable polymer microcapsules has been a challenging task due to production limitations stemming from solution viscosity, phase stabilization, molecular localization, and scalable production. We report an extension of Precision Particle Fabrication (PPF) technology for the production of monodisperse liquid-filled microcapsules containing an oil or aqueous core and contrast these results to double-walled microspheres. PPF technology utilizes a coaxial nozzle to produce a liquid core jet surrounded by a polymer annular jet, which is further encompassed by a non-solvent carrier stream, typically 0.5% wt/vol polyvinyl alcohol in water. Jet diameters are controlled by the volumetric flow rate of each phase. The compound jet is then disrupted into uniform core/shell droplets via a controllable acoustic wave and shell material is hardened by solvent extraction. Monodisperse polymeric microcapsules demonstrated a narrow size distribution and the formation of a continuous shell leading to efficient encapsulation of various liquid cores. The intermingling of core and shell phases and the localization of different molecular probes (fluorescent dyes and fluorescently labeled proteins) to the core or shell phase provided additional evidence of phase separation and molecular partitioning, respectively. We also demonstrate the pulsatile release of bovine serum albumin encapsulated in an aqueous core. PPF technology provided exceptional control of the overall size and shell thickness of microcapsules filled with various types of oil or water. This technique may enable advanced delivery profiles of pharmaceuticals or nutraceuticals.

  3. Micromachined chemical jet dispenser

    Science.gov (United States)

    Swierkowski, S.P.

    1999-03-02

    A dispenser is disclosed for chemical fluid samples that need to be precisely ejected in size, location, and time. The dispenser is a micro-electro-mechanical systems (MEMS) device fabricated in a bonded silicon wafer and a substrate, such as glass or silicon, using integrated circuit-like fabrication technology which is amenable to mass production. The dispensing is actuated by ultrasonic transducers that efficiently produce a pressure wave in capillaries that contain the chemicals. The 10-200 {micro}m diameter capillaries can be arranged to focus in one spot or may be arranged in a larger dense linear array (ca. 200 capillaries). The dispenser is analogous to some ink jet print heads for computer printers but the fluid is not heated, thus not damaging certain samples. Major applications are in biological sample handling and in analytical chemical procedures such as environmental sample analysis, medical lab analysis, or molecular biology chemistry experiments. 4 figs.

  4. Experimental Study of Water Jet Impingement Cooling of Hot Steel Plates

    OpenAIRE

    Karwa, Nitin

    2012-01-01

    Liquid jet impingement cooling is critical in many industrial applications. Principle applications include extracting large heat flux from metal parts, such as hot fuel bundle post-loss-of-coolant-accident in nuclear reactors, heat treatment of steel plates post-hot-processing, etc. The ability of liquid jets to extract high heat flux at controlled rates from metal parts, with temperatures as high as 800-1000 ºC, at moderate flow rates has made them indispensable in these applications. Due to...

  5. Jet Energy Corrections at CMS

    CERN Document Server

    Santocchia, Attilio

    2009-01-01

    Many physics measurements in CMS will rely on the precise reconstruction of Jets. Correction of the raw jet energy measured by the CMS detector will be a fundamental step for most of the analysis where hadron activity is investigated. Jet correction plans in CMS have been widely studied for different conditions: at stat-up simulation tuned on test-beam data will be used. Then data-driven methods will be available and finally, simulation tuned on collision data will give us the ultimate procedure for calculating jet corrections. Jet transverse energy is corrected first for pile-up and noise offset; correction for the response of the calorimeter as a function of jet pseudorapidity relative to the barrel comes afterwards and correction for the absolute response as a function of transverse momentum in the barrel is the final standard sub-correction applied. Other effects like flavour and parton correction will be optionally applied on the Jet $E_T$ depending on the measurement requests. In this paper w...

  6. Early Human Dispersals and Submerged Landscapes : comment on news feature "Migration: value of submerged early sites" in Nature's May 2012 special issue "Peopling the Planet"

    NARCIS (Netherlands)

    Flemming, Nicholas; Bailey, Geoffrey N.; Sakellariou, Dimitris; Arias, Pablo; Canals, M.; Chiocci, Francesco Latino; Cohen, K.M.; Erlandson, Jon; Faught, Michael K.; Flatman, Joe; Fischer, Anders; Galili, Ehud; Harff, Jan; Lericolais, Gilles; Lűth, Friedrich

    2012-01-01

    Your articles on human dispersal in the late Pleistocene epoch (Nature 485, 23; 2012) overlook the significance of now-submerged archaeological sites on the continental shelf during this period (126,000–11,000 years ago). It is wrong to assume that these were completely destroyed by the sea and that

  7. Analytical and experimental study of the acoustics and the flow field characteristics of cavitating self-resonating water jets

    Energy Technology Data Exchange (ETDEWEB)

    Chahine, G.L.; Genoux, P.F.; Johnson, V.E. Jr.; Frederick, G.S.

    1984-09-01

    Waterjet nozzles (STRATOJETS) have been developed which achieve passive structuring of cavitating submerged jets into discrete ring vortices, and which possess cavitation incipient numbers six times higher than obtained with conventional cavitating jet nozzles. In this study we developed analytical and numerical techniques and conducted experimental work to gain an understanding of the basic phenomena involved. The achievements are: (1) a thorough analysis of the acoustic dynamics of the feed pipe to the nozzle; (2) a theory for bubble ring growth and collapse; (3) a numerical model for jet simulation; (4) an experimental observation and analysis of candidate second-generation low-sigma STRATOJETS. From this study we can conclude that intensification of bubble ring collapse and design of highly resonant feed tubes can lead to improved drilling rates. The models here described are excellent tools to analyze the various parameters needed for STRATOJET optimizations. Further analysis is needed to introduce such important factors as viscosity, nozzle-jet interaction, and ring-target interaction, and to develop the jet simulation model to describe the important fine details of the flow field at the nozzle exit.

  8. Fermi liquids and Luttinger liquids

    OpenAIRE

    Schulz, H. J.; Cuniberti, G.; Pieri, P.

    1998-01-01

    In these lecture notes, the basic physics of Fermi liquids and Luttinger liquids is presented. Fermi liquids are discussed both from a phenomenological viewpoint, in relation to microscopic approaches, and as renormalization group fixed points. Luttinger liquids are introduced using the bosonization formalism, and their essential differences with Fermi liquids are pointed out. Applications to transport effects, the effect of disorder, quantum spin chains, and spin ladders, both insulating and...

  9. Medium Modification of Jet Shapes and Jet Multiplicities

    CERN Document Server

    Salgado, C A; Salgado, Carlos A.; Wiedemann, Urs Achim

    2004-01-01

    Medium-induced parton energy loss is widely considered to underly the suppression of high-pt leading hadron spectra in 200 GeV/A Au+Au collisions at RHIC. Its description implies a characteristic kt-broadening of the subleading hadronic fragments associated to the hard parton. However, this latter effect is more difficult to measure and remained elusive so far. Here, we discuss how it affects genuine jet observables which are accessible at LHC and possibly at RHIC. We find that the kt-broadening of jet multiplicity distributions provides a very sensitive probe of the properties of dense QCD matter, whereas the sensitivity of jet energy distributions is much weaker. In particular, the sensitive kinematic range of jet multiplicity distributions is almost unaffected by the high multiplicity background.

  10. A multimaterial electrohydrodynamic jet (E-jet) printing system

    Science.gov (United States)

    Sutanto, E.; Shigeta, K.; Kim, Y. K.; Graf, P. G.; Hoelzle, D. J.; Barton, K. L.; Alleyne, A. G.; Ferreira, P. M.; Rogers, J. A.

    2012-04-01

    Electrohydrodynamic jet (E-jet) printing has emerged as a high-resolution alternative to other forms of direct solution-based fabrication approaches, such as ink-jet printing. This paper discusses the design, integration and operation of a unique E-jet printing platform. The uniqueness lies in the ability to utilize multiple materials in the same overall print-head, thereby enabling increased degrees of heterogeneous integration of different functionalities on a single substrate. By utilizing multiple individual print-heads, with a carrousel indexing among them, increased material flexibility is achieved. The hardware design and system operation for a relatively inexpensive system are developed and presented. Crossover interconnects and multiple fluorescent tagged proteins, demonstrating printed electronics and biological sensing applications, respectively.

  11. Jet energy calibration in ATLAS

    CERN Document Server

    Schouten, Doug

    A correct energy calibration for jets is essential to the success of the ATLAS experi- ment. In this thesis I study a method for deriving an in situ jet energy calibration for the ATLAS detector. In particular, I show the applicability of the missing transverse energy projection fraction method. This method is shown to set the correct mean energy for jets. Pileup effects due to the high luminosities at ATLAS are also stud- ied. I study the correlations in lateral distributions of pileup energy, as well as the luminosity dependence of the in situ calibration metho

  12. Kinematical Diagrams for Conical Relativistic Jets

    Indian Academy of Sciences (India)

    ... a variety of radio observations of blazar jets. In addition to uniform jet flows (i.e., those having a uniform bulk Lorentz factor, ), computational results are also presented for stratified jets where an ultra-relativistic central spine along the jet axis is surrounded by a slower moving sheath, possibly arising from a velocity shear.

  13. Jet stream related observations by MST radars

    Science.gov (United States)

    Gage, K. S.

    1983-01-01

    An overview of the jet stream and its observation by MST radar is presented. The climatology and synoptic and mesoscale structure of jet streams is briefly reviewed. MST radar observations of jet stream winds, and associated waves and turbulence are then considered. The possibility of using a network of ST radars to track jet stream winds in near real time is explored.

  14. Differential Response of Floating and Submerged Leaves of Longleaf Pondweed to Silver Ions

    Directory of Open Access Journals (Sweden)

    Nisha Shabnam

    2017-06-01

    Full Text Available In this study, we have investigated variations in the potential of floating and submerged leaves of longleaf pondweed (Potamogeton nodosus to withstand silver ion (Ag+-toxicity. Both floating and submerged leaves changed clear colorless AgNO3 solutions to colloidal brown in the presence of light. Transmission electron microscopy revealed the presence of distinct crystalline Ag-nanoparticles (Ag-NPs in these brown solutions. Powder X-ray diffraction pattern showed that Ag-NPs were composed of Ag0 and Ag2O. Photosystem (PS II efficiency of leaves declined upon exposure to Ag+ with a significantly higher decline in the submerged leaves than in the floating leaves. Similarly, Ag+ treatment caused a significant reduction in the carboxylase activity of the ribulose bisphosphate carboxylase/oxygenase in leaves. The reduction in this carboxylase activity was significantly higher in the submerged than in the floating leaves. Ag+ treatment also resulted in a significant decline in the levels of non-enzymatic and enzymatic antioxidants; the decline was significantly lower in the floating than in submerged leaves. X-ray photoelectron spectroscopy revealed the presence of Ag2O in these leaves. Inductively coupled plasma mass spectrometry analysis revealed a three-fold higher Ag content in the submerged than in floating leaves. Our study demonstrates that floating leaves of longleaf pondweed have a superior potential to counter Ag+-toxicity compared with submerged leaves, which could be due to superior potential of floating leaves to reduce Ag+ to less/non-toxic Ag0/Ag2O-nanoparticles/nanocomplexes. We suggest that modulating the genotype of longleaf pondweed to bear higher proportion of floating leaves would help in cleaning fresh water bodies contaminated with ionic forms of heavy metals.

  15. Jet reconstruction and heavy jet tagging at LHCb

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    The jet reconstruction and the heavy jet flavour tagging at LHCb will be discussed with focus on the last published measurements such as the measurement of forward tt, W+bb and W+cc production in pp collisions at √s=8 TeV and the search for the SM Higgs boson decaying in bbbar or ccbar in association to W or Z boson.

  16. Multi-Objective Optimization of Submerged Arc Welding Process

    Directory of Open Access Journals (Sweden)

    Saurav Datta

    2010-06-01

    Full Text Available Submerged arc welding (SAW is an important metal fabrication technology specially applied to join metals of large thickness in a single pass. In order to obtain an efficient joint, several process parameters of SAW need to be studied and precisely selected to improve weld quality. Many methodologies were proposed in the past research to address this issue. However, a good number of past work seeks to optimize SAWprocess parameters with a single response only. In practical situations, not only is the influence of process parameters and their interactive effects on output responses are to be critically examined but also an attempt is to be made to optimize more than one response, simultaneously. To this end, the present study considers four process control parameters viz. voltage (OCV, wire feed rate, traverse speed and electrode stick-out. The selected weld quality characteristics related to features of bead geometry are depth of penetration, reinforcement and bead width. In the present reporting, an integrated approach capable of solving the simultaneous optimization of multi-quality responses in SAW was suggested. In the proposed approach, the responses were transformed into their individual desirability values by selecting appropriate desirability function. Assuming equal importance for all responses, these individual desirability values were aggregated to calculate the overall desirability values. Quadratic Response Surface Methodology (RSM was applied to establish a mathematical model representing overall desirability as a function involving linear, quadratic and interaction effect of process control parameters. This model was optimized finally within the experimental domain using PSO (Particle Swarm Optimization algorithm. A confirmatory test showed a satisfactory result. A detailed methodology of RSM, desirability function (DF and a PSO-based optimization approach was illustrated in the paper.

  17. Fallout plume of submerged oil from Deepwater Horizon

    Science.gov (United States)

    Valentine, David L.; Fisher, G. Burch; Bagby, Sarah C.; Nelson, Robert K.; Reddy, Christopher M.; Sylva, Sean P.; Woo, Mary A.

    2014-01-01

    The sinking of the Deepwater Horizon in the Gulf of Mexico led to uncontrolled emission of oil to the ocean, with an official government estimate of ∼5.0 million barrels released. Among the pressing uncertainties surrounding this event is the fate of ∼2 million barrels of submerged oil thought to have been trapped in deep-ocean intrusion layers at depths of ∼1,000–1,300 m. Here we use chemical distributions of hydrocarbons in >3,000 sediment samples from 534 locations to describe a footprint of oil deposited on the deep-ocean floor. Using a recalcitrant biomarker of crude oil, 17α(H),21β(H)-hopane (hopane), we have identified a 3,200-km2 region around the Macondo Well contaminated by ∼1.8 ± 1.0 × 106 g of excess hopane. Based on spatial, chemical, oceanographic, and mass balance considerations, we calculate that this contamination represents 4–31% of the oil sequestered in the deep ocean. The pattern of contamination points to deep-ocean intrusion layers as the source and is most consistent with dual modes of deposition: a “bathtub ring” formed from an oil-rich layer of water impinging laterally upon the continental slope (at a depth of ∼900–1,300 m) and a higher-flux “fallout plume” where suspended oil particles sank to underlying sediment (at a depth of ∼1,300–1,700 m). We also suggest that a significant quantity of oil was deposited on the ocean floor outside this area but so far has evaded detection because of its heterogeneous spatial distribution. PMID:25349409

  18. Spitting cobras: fluid jets in nature as models for technical applications

    Science.gov (United States)

    Balmert, Alexander; Hess, David; Brücker, Christoph; Bleckmann, Horst; Westhoff, Guido

    2011-04-01

    Spitting cobras defend themselves by ejecting rapid jets of venom through their fangs towards the face of an offender. To generate these jets, the venom delivery system of spitting cobras has some unique adaptations, such as prominent ridges on the surface of the venom channel. We examined the fluid acceleration mechanisms in three spitting cobra species of the genus Naja. To investigate the liquid-flow through the venom channel we built a three-dimensional 60:1 scale model. First we determined the three-dimensional structure of the channel by using microcomputer tomography. With help of the micro computer tomographical data we then created a negative form out of wax. Finally, silicon was casted around the wax form and the wax removed, resulting in a completely transparent model of the cobrás venom channel. The physical-chemical properties of the cobra venom were measured by micro rheometry and tensiometry. Thereafter, an artificial fluid with similar properties was generated. Particle image velocimetry (PIV) was performed to visualize the flow of the artificial liquid in the three-dimensional model. Our experiments show how the surface structure of the venom channel determines the liquid flow through the channel and ultimately the form of the liquid jet. Understanding the biological mechanisms of venom ejection helps to enhance industrial processes such as water jet cutting and cleaning as well as injection methods in technical and medical sectors, e.g. liquid microjet dissection in microsurgery.

  19. Submergence Causes Similar Carbohydrate Starvation but Faster Post-Stress Recovery than Darkness in Alternanthera philoxeroides Plants.

    Directory of Open Access Journals (Sweden)

    Xiao Qi Ye

    Full Text Available Carbon assimilation by submerged plants is greatly reduced due to low light levels. It is hypothesized that submergence reduces carbohydrate contents and that plants recover from submergence in the same way as darkness-treated plants. To test this hypothesis, the responses of plants to submergence and darkness were studied and compared. Plants of a submergence-tolerant species, Alternanthera philoxeroides, were exposed to well drained and illuminated conditions, complete submergence conditions or darkness conditions followed by a recovery growth period in a controlled experiment. The biomass maintenance and accumulation, carbohydrate content dynamics and respiration rate in the plants were assessed to quantify the carbohydrate utilization rate and regrowth. The submerged plants maintained higher chlorophyll contents, more green leaf tissue and more biomass; recovered more quickly; and accumulated more carbohydrates and biomass than darkness-treated plants. The respiration rate was continuously reduced in the same pattern under both stress conditions but was maintained at a significantly lower level in the submerged plants; the total soluble sugar and total fructan contents were decreased at approximately the same rate of decrease, reaching similar low levels, in the two stress treatments. The A. philoxeroides plants were more tolerant of submergence than darkness. The faster recovery of desubmerged plants could not be explained by the similar carbohydrate contents at the start of recovery. Other types of carbon reserves besides carbohydrates or other mechanisms such as higher post-stress photosynthetic performance might be involved.

  20. Tsilmanite as a new type of jet

    Science.gov (United States)

    Shumilov, I. Kh.

    2016-05-01

    A new type of jet from continental Devonian deposits of the Middle Timan is described. Fragments of Archaeopteris were the substrate for jet formation. Fossils in sandstone layers are characterized by a peculiar spheroidal jointing of organic matter; the material is fusainized completely. The jet is characterized by integration of the properties of classic jet and inertinite. The proper name tsilmanite is suggested for the new type of jet after the place of its discovery.

  1. Radial flow pulse jet mixer

    Science.gov (United States)

    VanOsdol, John G.

    2013-06-25

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  2. Instabilities in coaxial rotating jets

    Science.gov (United States)

    Ivanic, Tanja; Foucault, Eric; Pecheux, Jean; Gilard, Virginie

    2000-12-01

    The aim of this study is the characterization of the cylindrical mixing layer resulting from the interaction of two coaxial swirling jets. The experimental part of this study was performed in a cylindrical water tunnel, permitting an independent rotation of two coaxial jets. The rotations are generated by means of 2×36 blades localized in two swirling chambers. As expected, the evolution of the main instability modes presents certain differences compared to the plane-mixing-layer case. Experimental results obtained by tomography showed the existence of vortex rings and streamwise vortex pairs in the near field region. This method also permitted the observation of the evolution and interaction of different modes. PIV velocity measurements realized in the meridian plans and the plans perpendicular to the jet axis show that rotation distorts the typical top-hat axial velocity profile. The transition of the axial velocity profile from jet-like into wake-like is also observed.

  3. Venus: Jet-setting atmosphere

    Science.gov (United States)

    Hauchecorne, Alain

    2017-09-01

    A fast equatorial jet in the Venusian cloud layer has been revealed by the Akatsuki orbiter by tracking cloud movement in near-infrared images. The findings suggest that the Venusian atmosphere is more variable than previously thought.

  4. 4-jet events at LEP

    CERN Document Server

    Bizouard, M A

    1997-01-01

    Results of a special study made by the four LEP experiments on 4-jet events recorded at Vs = 130 - 136 , 161 and 172 GeV are related. This study concerns the ALEPH analysis which has shown an excess of 4-jet events in data recorded at Vs = 130 - 136 GeV. No significant evidence has been found by the 3 other experiments. Results have been combined after several checks which did not show differences of performance between the four LEP experiments.

  5. Solitary and cnoidal wave scattering by a submerged horizontal plate in shallow water

    Directory of Open Access Journals (Sweden)

    Masoud Hayatdavoodi

    2017-06-01

    Full Text Available Solitary and cnoidal wave transformation over a submerged, fixed, horizontal rigid plate is studied by use of the nonlinear, shallow-water Level I Green-Naghdi (GN equations. Reflection and transmission coefficients are defined for cnoidal and solitary waves to quantify the nonlinear wave scattering. Results of the GN equations are compared with the laboratory experiments and other theoretical solutions for linear and nonlinear waves in intermediate and deep waters. The GN equations are then used to study the nonlinear wave scattering by a plate in shallow water. It is shown that in deep and intermediate depths, the wave-scattering varies nonlinearly by both the wavelength over the plate length ratio, and the submergence depth. In shallow water, however, and for long-waves, only the submergence depth appear to play a significant role on wave scattering. It is possible to define the plate submergence depth and length such that certain wave conditions are optimized above, below, or downwave of the plate for different applications. A submerged plate in shallow water can be used as a means to attenuate energy, such as in wave breakers, or used for energy focusing, and in wave energy devices.

  6. [Influence of Submerged Plants on Microbial Community Structure in Sediment of Hongze Lake].

    Science.gov (United States)

    Zhang, Ding-yu; Zhang, Ting-xi; Dong, Dan-ping; Li, De-fang; Wang, Guo-xiang

    2016-05-15

    Phospholipid fatty acids (PLFAs) method was applied to analyze the influence of submerged plants on sediment microbial community structure, in order to investigate the changes of sediment microbial community structure for different kinds of the submerged plants in different growth periods. Particularly, Potamogeton crispus L., Potamogeton pectinatus L and the mixed group were chosen as the typical submerged plants in Hongze Lake for investigation in this paper. The results indicated that the change of total PLFAs in different periods was significant, on the contrary, the PLFA change for different groups in the same period was insignificant. The values of G⁺ PLFA/G⁻ PLFA in the submerged plant group were also highly related to the different growth periods, which demonstrated that the root function of the submerged plant had a severe impact on the microbial community in sediment. Furthermore, some environmental factors, such as Temperature, pH, TOC and DO, were correlated to characteristic phospholipid of PLFAs in sediment, which means the environmental factors could also affect the microbial community structure.

  7. Suspension of Egg Hatching Caused by High Humidity and Submergence in Spider Mites.

    Science.gov (United States)

    Ubara, Masashi; Osakabe, Masahiro

    2015-08-01

    We tested the effects of high humidity and submergence on egg hatching of spider mites. In both the high humidity and submergence treatments, many Tetranychus and Panonychus eggs did not hatch until after the hatching peak of the lower humidity or unsubmerged controls. However, after humidity decreased or water was drained, many eggs hatched within 1-3 h. This was observed regardless of when high humidity or submergence treatments were implemented: either immediately after oviposition or immediately before hatching was due. Normal eyespot formation was observed in most eggs in the high humidity and submergence treatments, which indicates that spider mite embryos develop even when eggs are underwater. Therefore, delays in hatching are not caused by delayed embryonic development. A delay in hatching was always observed in Panonychus citri (McGregor) but was more variable in Tetranychus urticae Koch and Tetranychus kanzawai Kishida. The high humidity and submergence treatments affected but did not suppress larval development in these species. In contrast, many Oligonychus eggs died following the high humidity treatments. In Tetranychus and Panonychus spider mites, suspension of egg hatching may mitigate the adverse effects of rainfall. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Individual and combined suppressive effects of submerged and floating-leaved macrophytes on algal blooms.

    Science.gov (United States)

    Seto, Mayumi; Takamura, Noriko; Iwasa, Yoh

    2013-02-21

    Shallow lakes and ponds are often characterised either by clear water with abundant submerged macrophytes or by turbid water with abundant phytoplankton. Blooms of toxic filamentous blue-green algae (cyanobacteria) often dominate the phytoplankton community in eutrophic lakes, which threatens ecological functions and biodiversity of freshwater ecosystems. We studied a simple lake model in order to evaluate individual and combined suppressive effects of rooted submerged and rooted floating-leaved macrophytes on algal blooms. Floating-leaved plants are superior competitors for light, whereas submerged plants absorb and reduce available phosphorus in a water column that rooted floating-leaved plants exploit to a lesser extent. We found that mixed vegetation that includes both submerged and floating-leaved plants is more resistant than vegetation comprised by a single plant type to algal invasion triggered by phosphorus loading. In addition, competitive exclusion of submerged plants by floating-leaved plants may promote an algal bloom. These predictions were confirmed by the decision tree analysis of field data from 35 irrigation ponds in Hyogo Prefecture, Japan. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Constructed tropical wetlands with integrated submergent-emergent plants for sustainable water quality management.

    Science.gov (United States)

    Tanaka, Norio; Jinadasa, K B S N; Werellagama, D R I B; Mowjood, M I M; Ng, W J

    2006-01-01

    Improvement of primary effluent quality by using an integrated system of emergent plants (Scirpus grossus in the leading subsurface flow arrangement) and submergent plants (Hydrilla verticillata in a subsequent channel) was investigated. The primary effluent was drawn from a septic tank treating domestic sewage from a student dormitory at the University of Peradeniya, Sri Lanka. Influent and effluent samples were collected once every 2 weeks from May 2004 through July 2005 and analyzed to determine water quality parameters. Both the emergent and submergent plants were harvested at predetermined intervals. The results suggested that harvesting prolonged the usefulness of the system and the generation of a renewable biomass with potential economic value. The mean overall pollutant removal efficiencies of the integrated emergent and submergent plant system were biological oxygen demand (BOD5), 65.7%; chemical oxygen demand (COD), 40.8%; ammonium (NH4+-N), 74.8%; nitrate (NO3--N), 38.8%; phosphate (PO43-), 61.2%; total suspended solids (TSS), 65.8%; and fecal coliforms, 94.8%. The submergent plant subsystem improved removal of nutrients that survived the emergent subsystem operated at low hydraulic retention times. The significant improvement in effluent quality following treatment by the submergent plant system indicates the value of incorporating such plants in wetland systems.

  10. Production of mycelium and blastospores of sp. in submerged culture

    African Journals Online (AJOL)

    Hirsutella sp. was grown in four liquid media containing either casamino acids, corn steep liquor, collagen peptone or casein peptone. These media were inoculated with a 7 day-old culture of mycelia and blastospores of Hirsutella sp. and the cultures incubated with shaking at 250 rpm at 26°C. The media containing corn ...

  11. Multiscale Modeling of Astrophysical Jets

    Directory of Open Access Journals (Sweden)

    James H. Beall

    2014-12-01

    Full Text Available We are developing the capability for a multi-scale code to model the energy deposition rate and momentum transfer rate of an astrophysical jet which generates strong plasma turbulence in its interaction with the ambient medium through which it propagates. We start with a highly parallelized version of the VH-1 Hydrodynamics Code (Coella and Wood 1984, and Saxton et al., 2005. We are also considering the PLUTO code (Mignone et al. 2007 to model the jet in the magnetohydrodynamic (MHD and relativistic, magnetohydrodynamic (RMHD regimes. Particle-in-Cell approaches are also being used to benchmark a wave-population models of the two-stream instability and associated plasma processes in order to determine energy deposition and momentum transfer rates for these modes of jet-ambient medium interactions. We show some elements of the modeling of these jets in this paper, including energy loss and heating via plasma processes, and large scale hydrodynamic and relativistic hydrodynamic simulations. A preliminary simulation of a jet from the galactic center region is used to lend credence to the jet as the source of the so-called the Fermi Bubble (see, e.g., Su, M. & Finkbeiner, D. P., 2012*It is with great sorrow that we acknowledge the loss of our colleague and friend of more than thirty years, Dr. John Ural Guillory, to his battle with cancer.

  12. Numerical Modeling of Munroe Jets

    Science.gov (United States)

    Mader, Charles; Gittings, Michael

    2007-06-01

    Munroe jets are formed by the oblique interaction of detonation products from two explosive charges separated by an air gap. The jet consists of a high velocity jet of low density precursor gases and particles that travel faster than the primary jet which is a high pressure regular shock reflection. The Los Alamos PHERMEX Data Volumes [1] contain 40 radiographs taken by Douglas Venable in the 1960's of Munroe Jets generated by Composition B explosive charges separated by 5 to 80 mm of air. In several of the experiments the Munroe jets interacted with thin Tantalum foils and with aluminum plates. The PHERMEX experiments were modeled using the AMR Eulerian reactive hydrodynamic code, NOBEL [2,3], When the detonation arrives at the bottom of the gap, the detonation product s expand against the air and precursor gases travel at high velocity ahead of the detonation wave in the explosive. The expanding detonation products from the explosive collide and result in a high pressure regular shock reflection.. Interaction with a metal plate consists of first the interaction of the precursor gases and then the high pressure regular shock reflection arrives to further damage the metal plate. [1] Los Alamos PHERMEX Data, Volumes I, II, and III, UC Press 1980. [2] Numerical Modeling of Water Waves, Second Edition, Charles L. Mader, CRC Press 2004 [3] Numerical Modeling of Explosions and Propellants, Charles L. Mader, CRC Press 1998.

  13. Molecular Beam Studies of Volatile Liquids and Fuel Surrogates Using Liquid MICR

    Science.gov (United States)

    2014-12-23

    vapor pressure liquids, including octane, isooctane, dodecane, squalane , methylnaphthalene, ethylene glycol, and Jet A and JP-8 fuels themselves...C12H26) and pure squalane (C30H62), in vacuum and monitored the recoiling Ne or O2 by a mass spectrometer (as shown schematically in Figure 2...75% of the translational energy of the O2 molecules is transferred to liquid dodecane and squalane , with little difference between the short and

  14. Electrospinning jet behaviors under the constraints of a sheath gas

    Directory of Open Access Journals (Sweden)

    Yang Zhao

    2016-11-01

    Full Text Available Increasing the ejection efficiency and uniformity of nanofibers is the key to applications of electrospinning technology. In this work, a novel electrospinning spinneret with a sheath gas passageway is designed. The frictional resistance that stems from the sheath gas provides additional stretching and restriction forces on the jet. The sheath gas also reduces interference and enhances the stability of the charged jet. A bead-on-strain simulation model is built up to determine the constraint effects of the sheath gas. Simulation results show that the sheath gas decreases the motion area and increases the stretching ratio of the liquid jet. The stretching force from the sheath gas decreases the diameter and increases the uniformity of the nanofiber. As the gas pressure increases from 0 kPa to 50 kPa, the critical voltage of the jet ejection decreases from 8.4 kV to 2.5 kV, the diameter of the nanofiber deposition zone decreases from 40 cm to 10 cm, and the diameter of the nanofibers decreases from 557.97 nm to 277.73 nm. The uniformity of nanofibers can be improved significantly using a sheath gas. The sheath gas contributes to the rapid deposition of a uniform nanofibrous membrane and the industrial applications of electrospinning.

  15. Propagation Of Dense Plasma Jets

    Science.gov (United States)

    Turchi, Peter J.; Davis, John F.

    1988-05-01

    A variety of schemes have been proposed over the last two decades for delivering lethal amounts of energy and/or momentum to targets such as missiles and high speed aircraft. Techniques have ranged from high energy lasers and high voltage charged-particle accelerators to less exotic but still challenging devices such as electromagnetic railguns. One class of technology involves the use of high speed plasmas. The primary attraction of such technology is the possibility of utilizing relatively compact accelerators and electrical power systems that could allow highly mobile and agile operation from rocket or aircraft platforms, or in special ordnance. Three years ago, R & D Associates examined the possibility of plasma propagation for military applications and concluded that the only viable approach consisted of long dense plasma jets, contained in radial equilibrium by the atmosphere, while propagating at speeds of about 10 km/s. Without atmospheric confinement the plasma density would diminish too rapidly for adequate range and lethality. Propagation of atmospherically-confined jets at speeds much greater than 10 km/s required significant increases in power levels and/or operating altitudes to achieve useful ranges. The present research effort has been developing the experimental conditions necessary to achieve reasonable comparison with theoretical predictions for plasma jet propagation in the atmosphere. Time-resolved measurements have been made of high speed argon plasma jets penetrating a helium background (simulating xenon jets propagating into air). Basic radial confinement of the jet has been observed by photography and spectroscopy and structures in the flow field resemble those predicted by numerical calculations. Results from our successful initial experiments have been used to design improved diagnostic procedures and arcjet source characteristics for further experiments. In experiments with a modified arcjet source, radial confinement of the jet is again

  16. Formation of keratinocyte multilayers on filters under airlifted or submerged culture conditions in medium containing calcium, ascorbic acid, and keratinocyte growth factor.

    Science.gov (United States)

    Seo, Akira; Kitagawa, Norio; Matsuura, Takashi; Sato, Hironobu; Inai, Tetsuichiro

    2016-11-01

    Three-dimensional (3D) cell culture is a powerful in vitro technique to study the stratification and differentiation of keratinocytes. However, culture conditions, including culture media, supplements, and scaffolds (e.g., collagen gels with or without fibroblasts), can vary considerably. Here, we evaluated the roles of calcium, L-ascorbic acid phosphate magnesium salt n-hydrate (APM), and keratinocyte growth factor (KGF) in a chemically defined medium, EpiLife, in 3D cultures of primary human epidermal keratinocytes directly plated on polycarbonate filter inserts under airlifted or submerged conditions. Eight culture media containing various combinations of these three supplements were examined. Calcium was necessary for the stratification and differentiation of keratinocytes based on the localization of keratins and involucrin. However, the localization patterns of keratins and integrin β4 were partially disrupted and Ki67-positive basal cells almost disappeared 3 weeks after airlift. The addition of KGF, but not APM, prevented these changes. Further addition of APM markedly improved the tissue architecture, including basal cell morphology and the appearance of keratohyalin granules and localized involucrin in the upper suprabasal cells, even after 1 week. Although the submerged culture also formed cornified epithelium-like multilayers, involucrin was localized in the cornified layer, where nuclei were often found. Based on these results, it is most effective to culture keratinocytes at the air-liquid interface in EpiLife medium supplemented with calcium, APM, and KGF to form well-organized and orthokeratinized multilayers as skin analogues.

  17. Exploring the Degradation of Gallotannins Catalyzed by Tannase Produced by Aspergillus niger GH1 for Ellagic Acid Production in Submerged and Solid-State Fermentation.

    Science.gov (United States)

    Chávez-González, Mónica L; Guyot, Sylvain; Rodríguez-Herrera, Raul; Prado-Barragán, Arely; Aguilar, Cristóbal N

    2017-11-27

    Due to great interest on producing bioactive compounds for functional foods and biopharmaceuticals, it is important to explore the microbial degradation of potential sources of target biomolecules. Gallotannins are polyphenols present in nature, an example of them is tannic acid which is susceptible to enzymatic hydrolysis. This hydrolysis is performed by tannase or tannin acyl hydrolase, releasing in this way, biomolecules with high-added value. In the present study, chemical profiles obtained after fungal degradation of tannic acid under two bioprocesses (submerged fermentation (SmF) and solid state fermentation (SSF)) were determined. In both fermentation systems (SmF and SSF), Aspergillus niger GH1 strain and tannic acid as a sole carbon source and inducer were used (the presence of tannic acid promotes production of enzyme tannase). In case of SSF, polyurethane foam (PUF) was used like as support of fermentation; culture medium only was used in case of submerged fermentation. Fermentation processes were monitored during 72 h; samples were taken kinetically every 8 h; and all extracts obtained were partially purified to obtain polyphenolic fraction and then were analyzed by liquid chromatography-mass spectrometry (LC-MS). Molecules like gallic acid and n-galloyl glucose were identified as intermediates in degradation of tannic acid; during SSF was identified ellagic acid production. The results obtained in this study will contribute to biotechnological production of ellagic acid.

  18. Liquid Hydrogen Propellant Tank Sub-Surface Pressurization with Gaseous Helium

    Science.gov (United States)

    Stephens, J. R.; Cartagena, W.

    2015-01-01

    A series of tests were conducted to evaluate the performance of a propellant tank pressurization system with the pressurant diffuser intentionally submerged beneath the surface of the liquid. Propellant tanks and pressurization systems are typically designed with the diffuser positioned to apply pressurant gas directly into the tank ullage space when the liquid propellant is settled. Space vehicles, and potentially propellant depots, may need to conduct tank pressurization operations in micro-gravity environments where the exact location of the liquid relative to the diffuser is not well understood. If the diffuser is positioned to supply pressurant gas directly to the tank ullage space when the propellant is settled, then it may become partially or completely submerged when the liquid becomes unsettled in a microgravity environment. In such case, the pressurization system performance will be adversely affected requiring additional pressurant mass and longer pressurization times. This series of tests compares and evaluates pressurization system performance using the conventional method of supplying pressurant gas directly to the propellant tank ullage, and then supplying pressurant gas beneath the liquid surface. The pressurization tests were conducted on the Engineering Development Unit (EDU) located at Test Stand 300 at NASA Marshall Space Flight Center (MSFC). EDU is a ground based Cryogenic Fluid Management (CFM) test article supported by Glenn Research Center (GRC) and MSFC. A 150 ft3 propellant tank was filled with liquid hydrogen (LH2). The pressurization system used regulated ambient helium (GHe) as a pressurant, a variable position valve to maintain flow rate, and two identical independent pressurant diffusers. The ullage diffuser was located in the forward end of the tank and was completely exposed to the tank ullage. The submerged diffuser was located in the aft end of the tank and was completely submerged when the tank liquid level was 10% or greater

  19. Survival after submergence in the pupae of five species of blow flies (Diptera: Calliphoridae).

    Science.gov (United States)

    Singh, D; Greenberg, B

    1994-09-01

    Survival of pupae of known ages after 1 to 5 d of submersion under water was assessed by determining the emergence of Protophormia terraenovae (Robineau-Desvoidy), Calliphora vicina (Robineau-Desvoidy), Cochliomyia macellaria (F.), Phormia regina (Meigen), and Phaenicia sericata (Meigen). Survival after 1 d of submergence was < 14% in the white puparial stage, 0-100% in pharate adults nearing eclosion, and approximately 100% in pupae between these two stages. This pattern inversely tracks O2 consumption during metamorphosis. Twenty-five percent of the pupae of three species (P. terraenovae, P. regina, and P. sericata) produced normal adults after 4 d of submersion, but none after 5 d. Among survivors, the pupation period was extended by the duration of submersion. Pupae of C. vicina were least able to withstand drowning. These data are potentially useful in estimating duration of submergence of a corpse in forensic investigations where the corpse becomes submerged after the larvae have developed and pupariated.

  20. Bioaccumulation of heavy metals by submerged macrophytes: looking for hyperaccumulators in eutrophic lakes.

    Science.gov (United States)

    Xing, Wei; Wu, Haoping; Hao, Beibei; Huang, Wenmin; Liu, Guihua

    2013-05-07

    To directly select submerged macrophytes with high accumulation capability from the field, 24 eutrophic lakes along the middle and lower reaches of the Yangtze River were investigated in the study. These eutrophic lakes have large amounts of heavy metals in both water and sediments because of human activities. The results showed that Najas marina is a hyperaccumulator of As and Cd, Ceratophyllum demersum is a hyperaccumulator of Co, Cr, and Fe, and Vallisneria natans is a hyperaccumulator of Pb. Strong positive correlations were found between concentrations of heavy metals in tissues of submerged macrophytes, probably because of coaccumulation of heavy metals. However, for most heavy metals, no significant correlations were found between submerged macrophytes and their surrounding environments. In conclusion, N. marina, C. demersum, and V. natans are good candidate species for removing heavy metals from eutrophic lakes.