Sample records for subcooled liquid nitrogen

  1. Liquid Acquisition Device Testing with Sub-Cooled Liquid Oxygen (United States)

    Jurns, John M.; McQuillen, John B.


    When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth s gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMD) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. Previous experimental test programs conducted at NASA have collected LAD data for a number of cryogenic fluids, including: liquid nitrogen (LN2), liquid oxygen (LOX), liquid hydrogen (LH2), and liquid methane (LCH4). The present work reports on additional testing with sub-cooled LOX as part of NASA s continuing cryogenic LAD development program. Test results extend the range of LOX fluid conditions examined, and provide insight into factors affecting predicting LAD bubble point pressures.

  2. Effects of Parallel Channel Interactions, Steam Flow, Liquid Subcool ...

    African Journals Online (AJOL)

    Tests were performed to examine the effects of parallel channel interactions, steam flow, liquid subcool and channel heat addition on the delivery of liquid from the upper plenum into the channels and lower plenum of Boiling Water Nuclear Power Reactors during reflood transients. Early liquid delivery into the channels, ...

  3. Maximum two-phase flow rates of subcooled nitrogen through a sharp-edged orifice (United States)

    Simoneau, R. J.


    An experiment was conducted and data are presented in which subcooled liquid nitrogen was discharged through a sharp-edged orifice at flow rates near the maximum. The data covered a range of inlet stagnation pressure from slightly above saturation to twice the thermodynamic critical pressure. The data were taken along five separate inlet stagnation isotherms ranging from 0.75 to 1.035 times the thermodynamic critical temperature. The results indicate that: (1) subcooled liquids do not choke or approach maximum flow in an asymptotic manner even though the back pressure is well below saturation; (2) orifice flow coefficients are not constant as is frequently assumed. A metastable jet appears to exist which breaks down if the difference between back pressure and saturation pressure is large enough.

  4. Sub-cooled nitrogen cryostat for 66 kV/750 A superconducting fault current limiter magnet

    CERN Document Server

    Ohtani, Y; Inoue, K; Kuriyama, T; Nomura, S; Ohkuma, T; Takahashi, Y; Yazawa, T


    As a part of the Super-conductive AC Equipment (Super-ACE) project presently being performed, an AC magnet for a fault current limiter (FCL) is being developed. The goal of the project is the development of 66 kV/750 A high Tc superconducting (HTS) FCL magnet, which is composed of six HTS coils operating at around 65 K. This paper describes a design of a sub-cooled nitrogen cryostat for the FCL magnet. Three sets of Gifford-McMahon (GM) cryocooler were used for cooling liquid nitrogen in the cryostat. Experimental results of cooling down and temperature stability during current flowing tests of the magnet were reported in this paper. The sub-cooled nitrogen of 65 K was successfully obtained in the vessel with 2.6 m/sup 3/ in volume. And the temperature uniformity was observed in both of the cooling down process and the coil energizing process.

  5. Determination of the subcooled liquid solubilities of PAHs in partitioning batch experiments

    Directory of Open Access Journals (Sweden)

    Lihua Liu


    Full Text Available Subcooled liquid solubility is the water solubility for a hypothetical state of liquid. It is an important parameter for multicomponent nonaqueous phase liquids (NAPLs containing polycyclic aromatic hydrocarbons (PAHs, which can exist as liquids even though most of the solutes are solid in their pure form at ambient temperature. So far, subcooled liquid solubilities were estimated from the solid water solubility and fugacity ratio of the solid and (subcooled liquid phase, but rarely derived from experimental data. In our study, partitioning batch experiments were performed to determine the subcooled liquid solubility of PAHs in NAPL-water system. For selected PAH, a series of batch experiments were carried out at increased mole fractions of the target component in the NAPL and at a constant NAPL/water volume ratio. The equilibrium aqueous PAH concentrations were measured with HPLC and/or GC-MS. The subcooled liquid solubility was derived by extrapolation of the experimental equilibrium aqueous concentration to a mole fraction of unity. With the derived subcooled liquid solubility, the fugacity ratio and enthalpy of fusion of the solute were also estimated. Our results show a good agreement between the experimentally determined and published data.

  6. Interfacial instability of a condensing vapor bubble in a subcooled liquid (United States)

    Ueno, I.; Ando, J.; Koiwa, Y.; Saiki, T.; Kaneko, T.


    A special attention is paid to the condensing and collapsing processes of vapor bubble injected into a subcooled pool. We try to extract the vapor-liquid interaction by employing a vapor generator that supplies vapor to the subcooled pool through an orifice instead of using a immersed heating surface to realize vapor bubbles by boiling phenomenon. This system enables ones to detect a spatio-temporal behavior of a single bubble of superheated vapor exposed to a subcooled liquid. In the present study, vapor of water is injected through an orifice at constant flow rate to the subcooled pool of water at the designated degree of subcooling under the atmospheric pressure. The degree of subcooling of the pool is ranged from 0 K to 70 K, and the vapor temperature is kept constant at 101 ∘C. The behaviors of the injected vapor are captured by high-speed camera at frame rate up to 0.3 million frame per second (fps) to track the temporal variation of the vapor bubble shape. It is found that the abrupt collapse of the vapor bubble exposed to the subcooled pool takes place under the condition that the degree of subcooling is greater than around 30 K, and that the abrupt collapse always takes place accompanying the fine disturbances or instability emerged on the free surface. We then evaluate a temporal variation of the apparent `volume' of the bubble V under the assumption of the axisymmetric shape of the vapor bubble. It is also found that the instability emerges slightly after the volume of the vapor bubble reaches the maximum value. It is evaluated that the second derivative of the corresponding `radius' R of the vapor bubble is negative when the instability appears on the bubble surface, where R = 3√ 3V/4π. We also illustrate that the wave number of the instability on the liquid-vapor interface increases as the degree of subcooling.

  7. Liquid Nitrogen Subcooler Pressure Vessel Engineering Note

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, R.; /Fermilab


    The normal operating pressure of this dewar is expected to be less than 15 psig. This vessel is open to atmospheric pressure thru a non-isolatable vent line. The backpressure in the vent line was calculated to be less than 1.5 psig at maximum anticipated flow rates.

  8. Consideration of sub-cooled LN2 circulation system for HTS power machines (United States)

    Yoshida, Shigeru; Hirai, Hirokazu; Nara, N.; Nagasaka, T.; Hirokawa, M.; Okamoto, H.; Hayashi, H.; Shiohara, Y.


    We consider a sub-cooled liquid nitrogen (LN) circulation system for HTS power equipment. The planned circulation system consists of a sub-cool heat exchanger (subcooler) and a circulation pump. The sub-cooler will be connected to a neon turbo- Brayton cycle refrigerator with a cooling power of 2 kW at 65 K. Sub-cooled LN will be delivered into the sub-cooler by the pump and cooled within it. Sub-cooled LN is adequate fluid for cooling HTS power equipment, because its dielectric strength is high and it supports a large critical current. However, a possibility of LN solidification in the sub-cooler is a considerable issue. The refrigerator will produce cold neon gas of about 60 K, which is lower than the nitrogen freezing temperature of 63 K. Therefore, we designed two-stage heat exchangers which are based on a plate-fin type and a tube-intube type. Process simulations of those heat exchangers indicate that sub-cooled LN is not frozen in either sub-cooler. The plate-fin type sub-cooler is consequently adopted for its reliability and compactness. Furthermore, we found that a cooling system with a Brayton refrigerator has the same total cooling efficiency as a cooling system with a Stirling refrigerator.

  9. Aspects of subcooled boiling

    Energy Technology Data Exchange (ETDEWEB)

    Bankoff, S.G. [Northwestern Univ., Evanston, IL (United States)


    Subcooled boiling boiling refers to boiling from a solid surface where the bulk liquid temperature is below the saturation temperature (subcooled). Two classes are considered: (1) nucleate boiling, where, for large subcoolings, individual bubbles grow and collapse while remaining attached to the solid wall, and (2) film boiling, where a continuous vapor film separates the solid from the bulk liquid. One mechanism by which subcooled nucleate boiling results in very large surface heat transfer coefficient is thought to be latent heat transport within the bubble, resulting from simultaneous evaporation from a thin residual liquid layer at the bubble base, and condensation at the polar bubble cap. Another is the increased liquid microconvection around the oscillating bubble. Two related problems have been attacked. One is the rupture of a thin liquid film subject to attractive and repulsive dispersion forces, leading to the formation of mesoscopic drops, which then coalesce and evaporate. Another is the liquid motion in the vicinity of an oscillating contact line, where the bubble wall is idealized as a wedge of constant angle sliding on the solid wall. The subcooled film boiling problem has been attacked by deriving a general long-range nonlinear evolution equation for the local thickness of the vapor layer. Linear and weakly-nonlinear stability results have been obtained. A number of other related problems have been attacked.

  10. Characteristics of Subcooled Liquid Methane During Passage Through a Spray-Bar Joule-Thompson Thermodynamic Vent System (United States)

    Hastings, L. J.; Bolshinskiy, L. G.; Hedayat, A.; Schnell, A.


    NASA s Marshall Space Flight Center (MSFC) conducted liquid methane (LCH4) testing in November 2006 using the multipurpose hydrogen test bed (MHTB) outfitted with a spray-bar thermodynamic vent system (TVS). The basic objective was to identify any unusual or unique thermodynamic characteristics associated with subcooled LCH4 that should be considered in the design of space-based TVSs. Thirteen days of testing were performed with total tank heat loads ranging from 720 W to 420 W at a fill level of approximately 90%. During an updated evaluation of the data, it was noted that as the fluid passed through the Joule Thompson expansion, thermodynamic conditions consistent with the pervasive presence of metastability were indicated. This paper describes the observed thermodynamic conditions that correspond with metastability and effects on TVS performance.

  11. Solid state and sub-cooled liquid vapour pressures of substituted dicarboxylic acids using Knudsen Effusion Mass Spectrometry (KEMS and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    A. M. Booth


    Full Text Available Solid state vapour pressures of a selection of atmospherically important substituted dicarboxylic acids have been measured using Knudsen Effusion Mass Spectrometry (KEMS over a range of 20 K (298–318 K. Enthalpies of fusion and melting points obtained using Differential Scanning Calorimetry (DSC were used to obtain sub-cooled liquid vapour pressures. They have been compared to estimation methods used on the E-AIM website. These methods are shown to poorly represent – OH groups in combination with COOH groups. Partitioning calculations have been performed to illustrate the impact of the different estimation methods on organic aerosol mass compared to the use of experimental data.

  12. Characteristic evaluation of cooling technique using liquid nitrogen and metal porous media

    Energy Technology Data Exchange (ETDEWEB)

    Tanno, Yusuke; Ito, Satoshi; Hashizume, Hidetoshi [Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi 980-8579 (Japan)


    A remountable high-temperature superconducting magnet, whose segments can be mounted and demounted repeatedly, has been proposed for construction and maintenance of superconducting magnet and inner reactor components of a fusion reactor. One of the issues in this design is that the performance of the magnet deteriorates by a local temperature rise due to Joule heating in jointing regions. In order to prevent local temperature rise, a cooling system using a cryogenic coolant and metal porous media was proposed and experimental studies have been carried out using liquid nitrogen. In this study, flow and heat transfer characteristics of cooling system using subcooled liquid nitrogen and bronze particle sintered porous media are evaluated through experiments in which the inlet degree of subcooling and flow rate of the liquid nitrogen. The flow characteristics without heat input were coincided with Ergun’s equation expressing single-phase flow in porous materials. The obtained boiling curve was categorized into three conditions; convection region, nucleate boiling region and mixed region with nucleate and film boiling. Wall superheat did not increase drastically with porous media after departure from nucleate boiling point, which is different from a situation of usual boiling curve in a smooth tube. The fact is important characteristic to cooling superconducting magnet to avoid its quench. Heat transfer coefficient with bronze particle sintered porous media was at least twice larger than that without the porous media. It was also indicated qualitatively that departure from nucleate boiling point and heat transfer coefficient depends on degree of subcooling and mass flow rate. The quantitative evaluation of them and further discussion for the cooling system will be performed as future tasks.

  13. Condensation of vapor bubble in subcooled pool (United States)

    Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.


    We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

  14. Liquid nitrogen ingestion followed by gastric perforation. (United States)

    Berrizbeitia, Luis D; Calello, Diane P; Dhir, Nisha; O'Reilly, Colin; Marcus, Steven


    Ingestion of liquid nitrogen is rare but carries catastrophic complications related to barotrauma to the gastrointestinal tract. We describe a case of ingestion of liquid nitrogen followed by gastric perforation and respiratory insufficiency and discuss the mechanism of injury and management of this condition. Liquid nitrogen is widely available and is frequently used in classroom settings, in gastronomy, and for recreational purposes. Given the potentially lethal complications of ingestion, regulation of its use, acquisition, and storage may be appropriate.

  15. Automatic Transmission Of Liquid Nitrogen

    Directory of Open Access Journals (Sweden)

    Sumedh Mhatre


    Full Text Available Liquid Nitrogen is one of the major substance used as a chiller in industry such as Ice cream factory Milk Diary Storage of blood sample Blood Bank etc. It helps to maintain the required product at a lower temperature for preservation purpose. We cannot fully utilise the LN2 so practically if we are using 3.75 litre LN2 for a single day then around 12 of LN2 450 ml is wasted due to vaporisation. A pressure relief valve is provided to create a pressure difference. If there is no pressure difference between the cylinder carrying LN2 and its surrounding it will results in damage of container as well as wastage of LN2.Transmission of LN2 from TA55 to BA3 is carried manually .So care must be taken for the transmission of LN2 in order to avoid its wastage. With the help of this project concept the transmission of LN2 will be carried automatically so as to reduce the wastage of LN2 in case of manual operation.

  16. Subcooled boiling heat transfer in a short vertical SUS304-tube at liquid Reynolds number range 5.19 x 10{sup 4} to 7.43 x 10{sup 5}

    Energy Technology Data Exchange (ETDEWEB)

    Hata, Koichi, E-mail: [Institute of Advanced Energy, Kyoto Univ., Gokasho, Uji, Kyoto 611-0011 (Japan); Masuzaki, Suguru, E-mail: [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan)


    The subcooled boiling heat transfer and the steady-state critical heat fluxes (CHFs) in a short vertical SUS304-tube for the flow velocities (u = 17.28-40.20 m/s), the inlet liquid temperatures (T{sub in} = 293.30-362.49 K), the inlet pressures (P{sub in} = 842.90-1467.93 kPa) and the exponentially increasing heat input (Q = Q{sub 0} exp(t/tau), tau = 8.5 s) are systematically measured by the experimental water loop comprised of a multistage canned-type circulation pump with high pump head. The SUS304 test tubes of inner diameters (d = 3 and 6 mm), heated lengths (L = 33 and 59.5 mm), effective lengths (L{sub eff} = 23.3 and 49.1 mm), L/d (=11 and 9.92), L{sub eff}/d (=7.77 and 8.18), and wall thickness (delta = 0.5 mm) with average surface roughness (Ra = 3.18 mum) are used in this work. The inner surface temperature and the heat flux from non-boiling to CHF are clarified. The subcooled boiling heat transfer for SUS304 test tube is compared with our Platinum test tube data and the values calculated by other workers' correlations for the subcooled boiling heat transfer. The influence of flow velocity on the subcooled boiling heat transfer and the CHF is investigated into details and the widely and precisely predictable correlation of the subcooled boiling heat transfer for turbulent flow of water in a short vertical SUS304-tube is given based on the experimental data. The correlation can describe the subcooled boiling heat transfer obtained in this work within 15% difference. Nucleate boiling surface superheats for the SUS304 test tube become very high. Those at the high flow velocity are close to the lower limit of Heterogeneous Spontaneous Nucleation Temperature. The dominant mechanisms of the flow boiling CHF in a short vertical SUS304-tube are discussed.

  17. Cryostabilization of high-temperature superconducting magnets with subcooled flow in microchannels

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Y.S.; Hull, J.R.; Choi, U.S.


    Subcooled flow of liquid nitrogen in microchannels is proposed as a means to enhance the stability of a superconducting magnet. Analysis shows high current density or a low stabilizer fraction is obtainable in a cryostable magnet. Increase in stability (using the Stekley criterion) is directly related to coolant velocity and coolant channel aspect ratio, however, there is a corresponding increase in pressure drop of the system. Another constraint is the coolant temperature rise, which is found to be a function of coolant residence time and the coolant to conductor ratio.

  18. Liquid Nitrogen Zero Boiloff Testing (United States)

    Plachta, David; Feller, Jeffrey; Johnson, Wesley; Robinson, Craig


    Cryogenic propellants such as liquid hydrogen (LH2) and liquid oxygen (LO2) are a part of NASAs future space exploration due to their high specific impulse for rocket motors of upper stages suitable for transporting 10s to 100s of metric tons of payload mass to destinations outside of low earth orbit and for their return. However, the low storage temperatures of LH2 and LO2 cause substantial boil-off losses for missions with durations greater than several months. These losses can be eliminated by incorporating high performance cryocooler technology to intercept heat load to the propellant tanks and modulating the cryocooler to control tank pressure. The active thermal control technology being developed by NASA is the reverse turbo-Brayton cycle cryocooler and its integration to the propellant tank through a distributed cooling tubing network coupled to the tank wall. This configuration was recently tested at NASA Glenn Research Center, in a vacuum chamber and cryo-shroud that simulated the essential thermal aspects of low Earth orbit, its vacuum and temperature. Testing consisted of three passive tests with the active cryo-cooler system off, and 7 active tests, with the cryocooler powered up. The test matrix included zero boil-off tests performed at 90 full and 25 full, and several demonstrations at excess cooling capacity and reduced cooling capacity. From this, the tank pressure response with varied cryocooler power inputs was determined. This test series established that the active cooling system integrated with the propellant tank eliminated boil-off and robustly controlled tank pressure.

  19. Correlation of Helium Solubility in Liquid Nitrogen (United States)

    VanDresar, Neil T.; Zimmerli, Gregory A.


    A correlation has been developed for the equilibrium mole fraction of soluble gaseous helium in liquid nitrogen as a function of temperature and pressure. Experimental solubility data was compiled and provided by National Institute of Standards and Technology (NIST). Data from six sources was used to develop a correlation within the range of 0.5 to 9.9 MPa and 72.0 to 119.6 K. The relative standard deviation of the correlation is 6.9 percent.

  20. Sliding bubbles on a hot horizontal wire in a subcooled bath (United States)

    Duchesne, Alexis; Dubois, Charles; Caps, Hervé


    When a wire is heated up to the boiling point in a liquid bath some bubbles will nucleate on the wire surface. Traditional nucleate boiling theory predicts that bubbles generate from active nucleate site, grow up and depart from the heating surface due to buoyancy and inertia. However, an alternative scenario is presented in the literature for a subcooled bath: bubbles slide along the horizontal wire before departing. New experiments were performed by using a constantan wire and different liquids, varying the injected power. Silicone oil, water and even liquid nitrogen were tested in order to vary wetting conditions, liquid viscosities and surface tensions. We explored the influence of the wire diameter and of the subcooled bath temperature. We observed, of course, sliding motion, but also a wide range of behaviors from bubbles clustering to film boiling. We noticed that bubbles could change moving sense, especially when encountering with another bubble. The bubble speed is carefully measured and can reach more than 100 mm/s for a millimetric bubble. We investigated the dependence of the speed on the different parameters and found that this speed is, for a given configuration, quite independent of the injected power. We understand these phenomena in terms of Marangoni effects. This project has been financially supported by ARC SuperCool contract of the University of Liège.

  1. The automatic liquid nitrogen filling system for GDA detectors

    Indian Academy of Sciences (India)

    An indigenously developed automatic liquid nitrogen (LN2) filling system has been installed in gamma detector array (GDA) facility at Nuclear Science Centre. Electro-pneumatic valves are used for filling the liquid nitrogen into the high purity germanium detector cryostat. The temperature of the out-flowing gas/liquid from ...

  2. Cooling by immersion in liquid nitrogen (United States)

    Listerman, Thomas W.; Boshinski, Thomas A.; Knese, Lynn F.


    When an object is cooled by immersion in a liquid, there is an unexpected increase in the violence of boiling just before the boiling stops. Most people seem fascinated by this phenomenon yet few are acquainted with its explanation in terms of a change in the heat-transfer mechanism from film boiling to nucleate boiling. We have developed two variations of an intermediate level undergraduate laboratory experiment to measure the heat-transfer rate after a sample is immersed in liquid nitrogen. The temperature of the sample, as measured by a thermocouple, is recorded as a function of time using either a potentiometer strip-chart recorder or a digital voltmeter-microcomputer combination. The heat-transfer rate as a function of sample temperature is computed from these results, and the reason for the effect is clearly seen.

  3. Dynamics of explosive boiling and third heat transfer crisis at subcooling on a vertical surface (United States)

    Avksentyuk, B. P.; Ovchinnikov, V. V.


    Results of experimental studies on dynamics of explosive boiling and third heat transfer crisis under the conditions of liquid subcooling are presented for the vertical arrangement of the heat-transfer surface. Acetone was used in experiments at the pressure in the working volume from 20 to 46 kPa and subcooling from 0 to 20 K. The studied processes were recorded. Data on the velocity of evaporation front propagation at liquid subcooling were obtained. These data are compared with the results of calculations according to the models available in the literature. The effect of liquid subcooling on the regions of regime parameters corresponding to explosive boiling and third heat transfer crisis is studied.

  4. Electric pulse resistance of liquid nitrogen and rubber (United States)

    Kurets, V. I.; Tarakanovskii, É. N.; Filatov, G. P.


    We report the results of experimental investigations of the breakdown amplitudes of pulsed voltages applied to centimeter-thick layers of liquid nitrogen and various kinds of rubber at 77 K. We report the characteristics of pulses that will puncture rubber in liquid nitrogen.

  5. Liquid Nitrogen Cryotherapy for Surface Eye Disease (An AOS Thesis) (United States)

    Fraunfelder, Frederick Web


    Purpose To evaluate the effects of new treatments with liquid nitrogen cryotherapy on some external eye conditions. Methods In this retrospective case study, 6 separate series from a single tertiary care referral center practice are described. Liquid nitrogen cryotherapy was used to treat conjunctival amyloidosis, primary pterygia, recurrent pterygia, advancing wavelike epitheliopathy (AWLE), superior limbic keratoconjunctivitis (SLK), and palpebral vernal keratoconjunctivitis (VKC). The main outcome measure was the resolution of the disease process after treatment. Results Four patients with primary localized conjunctival amyloidosis were treated with liquid nitrogen cryotherapy. Two of them had recurrence of the amyloidosis, which cleared with subsequent treatment. Eighteen patients with primary pterygia had excision and cryotherapy with 1 recurrence. Of 6 subjects who presented with recurrent pterygia, 4 had a second recurrence after excision and cryotherapy. In 5 patients with AWLE, the condition resolved within 2 weeks without recurrence or the need for subsequent cryotherapy. Four patients with SLK were treated with liquid nitrogen cryotherapy. Disease recurred in 2 patients and 3 of 7 eyes, although subsequent cryotherapy eradicated SLK in all cases. Two patients and 3 eyelids with palpebral VKC were treated with liquid nitrogen cryotherapy. VKC recurred in all cases. Conclusions Liquid nitrogen cryotherapy to the surface of the eye is effective in treating AWLE, and SLK. Excision followed by cryotherapy is successful in treating conjunctival amyloidosis and primary pterygia Liquid nitrogen cryotherapy is unsuccessful in the treatment of recurrent pterygia and VKC. PMID:19277243

  6. Structural and electronic properties of dense liquid and amorphous nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Boates, B; Bonev, S A


    We present first-principles calculations of the structural and electronic properties of liquid nitrogen in the pressure-temperature range of 0-200 GPa and 2000-6000 K. The molecular-polymerization and molecular-atomic liquid phase boundaries have been mapped over this region. We find the polymeric liquid to be metallic, similar to what has been reported for the higher-temperature atomic fluid. An explanation of the electronic properties is given based on the structure and bonding character of the transformed liquids. We discuss the structural and bonding differences between the polymeric liquid and insulating solid cubic-gauche nitrogen to explain the differences in their electronic properties. Furthermore, we discuss the mechanism responsible for charge transport in polymeric nitrogen systems to explain the conductivity of the polymeric fluid and the semi-conducting nature of low-temperature amorphous nitrogen.

  7. Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air


    Yongjun Men; Martina Ambrogi; Baohang Han; Jiayin Yuan


    Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m2/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection.

  8. Downward transfer of a sub-cooled cryoliquid

    CERN Document Server

    Wertelaers, P


    An alternative is proposed to the traditional transfer of a cryo fluid in gaseous -- and warm -- form, a method of low productivity and high energy cost. In order to prevent the much-feared geysering, focus is on sub-cooling of the liquid, and the safe maintaining of such state all along the journey. A cryogenic transfer line of simplest construction is proposed, and the difficulties with such line extending over a transfer depth of the order of the kilometre, are discussed.

  9. Relative Efficacy of Liquid Nitrogen Fertilizers in Dryland Spring Wheat

    National Research Council Canada - National Science Library

    Walsh, Olga S; Christiaens, Robin J


    ... (total of 6 site-years) to evaluate the relative efficacy of three liquid nitrogen (N) fertilizer sources, urea ammonium nitrate (UAN, 32-0-0), liquid urea (LU, 21-0-0), and High NRGN (HNRGN, 27-0-0-1S), in spring wheat (Triticum aestivum L...

  10. Changes of enthalpy slope in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Francisco J.; Monne, Carlos [Universidad de Zaragoza-CPS, Departamento de Ingenieria Mecanica-Motores Termicos, Zaragoza (Spain); Pascau, Antonio [Universidad de Zaragoza-CPS, Departamento de Ciencia de los Materiales y Fluidos-Mecanica de Fluidos, Zaragoza (Spain)


    Void fraction data in subcooled flow boiling of water at low pressure measured by General Electric in the 1960s are analyzed following the classical model of Griffith et al. (in Proceedings of ASME-AIChE heat transfer conference, 58-HT-19, 1958). In addition, a new proposal for analyzing one-dimensional steady flow boiling is used. This is based on the physical fact that if the two phases have different velocities, they cannot cover the same distance - the control volume length - in the same time. So a slight modification of the heat balance is suggested, i.e., the explicit inclusion of the vapor-liquid velocity ratio or slip ratio as scaling time factor between the phases, which is successfully checked against the data. Finally, the prediction of void fraction using correlations of the net rate of change of vapor enthalpy in the fully developed regime of subcooled flow boiling is explored. (orig.)

  11. Effect of subcooling on the on-orbit pressurization rate of cryogenic propellant tankage (United States)

    Hochstein, J. I.; Ji, H.-C.; Aydelott, J. C.


    The SOLA-ECLIPSE code is being developed to enable prediction of the behavior of cryogenic propellants in spacecraft tankage. A brief description of the formulations used for modeling heat transfer and for determining thermodynamic state is presented. Code performance is verified through comparison to experimental data for the self-pressurization of scale model liquid hydrogen tanks. SOLA-ECLIPSE is used to examine the effect of initial subcooling of the liquid phase on the self-pressurization rate of an on-orbit full scale liquid hydrogen tank typical for a chemical propulsion Orbital Transfer Vehicle. The computational predictions show that even small amounts of subcooling will significantly decrease the self-pressurization rate. Further, if the cooling is provided by a Thermodynamic Vent System, it is concluded that small levels of subcooling will maximize propellant conservation.

  12. Study on vapor film collapse behavior on high temperature particle surface. 2nd Report. Effect of subcooling on micro-mechanism; Koon ryushi hyomenjo no jokimaku hokai ni kansuru kenkyu. 2. Bishiteki hokai kyodo ni oyobosu subcooling no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Y.; Tochio, D. [Yamagata University, Yamagata (Japan). Faculty of Engineering


    Thermal detonation model is proposed to describe vapor explosion. According to this model, vapor film on pre-mixed high temperature droplet surface should be collapsed for the trigger of the vapor explosion. It is pointed out that the vapor film collapse behavior is significantly affected by the subcooling of low temperature liquid. However, the effect of subcooling on micro-mechanism of vapor film collapse behavior is not experimentally well identified. The objective of the present research is to experimentally investigate the effect of subcooling on micro-mechanism of film boiling collapse behavior. As the results, it is experimentally clarified that the vapor film collapse behavior in low subcool condition is qualitatively different from the vapor film collapse behavior in high subcool condition. In high subcool condition, instability of the vapor film dominates the vapor film collapse on the particle surface. On the other hand, micro-mechanism at the interface between vapor and liquid such as micro-jet is dominant in low subcool condition in case of vapor film collapse by pressure pulse. (author)

  13. Study on vapor film collapse behavior on high temperature particle surface. 2. Effect of subcooling on micro-mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Yutaka [Yamagata University, Dept. of Mechanical Systems Engineering, Yonezawa, Yamagata (Japan); Tochio, Daisuke [Yamagata Univ. (Japan)


    Thermal detonation model is proposed to describe vapor explosion. According to this model, vapor film on pre-mixed high temperature droplet surface should be collapsed for the trigger of the vapor explosion. It is pointed out that the vapor film collapse behavior is significantly affected by the subcooling of low temperature liquid. However, the effect of subcooling on micro-mechanism of vapor film collapse behavior is not experimentally well identified. The objective of the present research is to experimentally investigate the effect of subcooling on micro-mechanism of film boiling collapse behavior. As the results, it is experimentally clarified that the vapor film collapse behavior in low subcool condition is qualitatively different from the vapor film collapse behavior in high subcool condition. In high subcool condition, instability of the vapor film dominates the vapor film collapse on the particle surface. On the other hand, micro-mechanism at the interface between vapor and liquid such as micro-jet is dominant in low subcool condition in case of vapor film collapse by pressure pulse. (author)

  14. High Speed Compressor for Subcooling Propellants Project (United States)

    National Aeronautics and Space Administration — The most promising propellant subcooling systems for LH2 require compression systems that involve development of significant head. The inlet pressure for these...

  15. Isolating silkworm genomic DNA without liquid nitrogen suitable for ...

    African Journals Online (AJOL)

    Genomic DNA was isolated from posterior silk gland of silkworms, Antheraea assama. Absolute alcohol was used as tissue fixing solution instead of grinding in liquid nitrogen, which yielded high molecular weight DNA (>40 kb). Samples yielded similar amount of DNA when fixed in absolute alcohol (400 μmg/g of silk gland ...

  16. Liquid Nitrogen Dewar Loading at KSC for STS-71 Flight (United States)


    Liquid nitrogen dewar loading at Kennedy Space Center for STS-71 flight with Stan Koszelak (right), University of California at Riverside, adn Tamara Chinareva (left), Russian Spacecraft Coporation-Energia. The picture shows Koszelak removing the insert from the transportation dewar.

  17. Effectiveness of liquid organic-nitrogen fertilizer in enhancing ...

    African Journals Online (AJOL)

    The ever increasing price of nitrogenous (N) fertilizers coupled with the deleterious effects of imbalanced N fertilizers on the environment necessitates the enhancement of N use efficiency of plants. The objectives of this study were to: (1) Evaluate the uptake of selected nutrients due to application of liquid organic-N ...

  18. effect of liquid nitrogen storage time on the survival and ...

    African Journals Online (AJOL)


    Investigations were undertaken on the effect of liquid nitrogen (LN) storage time on survival and regeneration of somatic embryos of cocoa (Theobroma cacao l.). Somatic embryos from different cocoa genotypes (AMAZ 3-. 2, AMAZ 10-1, AMAZ 12, SIAL 93, and IMC 14) at 15.45% moisture content were cryopreserved in LN ...

  19. Liquid Nitrogen Cryotherapy for Conjunctival Lymphangiectasia: A Case Series (United States)

    Fraunfelder, Frederick W.


    Purpose: To report a case series of conjunctival lymphangiectasia treated with liquid nitrogen cryotherapy. Methods: A 1.5-mm Brymill cryoprobe was applied in a double freeze-thaw method after an incisional biopsy of a portion of the conjunctiva in patients with conjunctival lymphangiectasia. Freeze times were 1 to 2 seconds with thawing of 5 to 10 seconds between treatments. Patients were reexamined at 1 day, 2 weeks, 3 months, 6 months, and yearly following cryotherapy. Results: Five eyes of 4 patients (3 male and 1 female) with biopsy-proven conjunctival lymphangiectasia underwent liquid nitrogen cryotherapy. The average patient age was 53 years. Ocular examination revealed large lymphatic vessels that were translucent and without conjunctival injection. Subjective symptoms included epiphora, ocular irritation, eye redness, and occasional blurred vision. After treatment with liquid nitrogen cryotherapy, the patients’ symptoms and signs resolved within 2 weeks. Lymphangiectasia recurred twice in one patient, at 1 and 3 years postoperatively. In another patient, lymphangiectasia recurred at 6 months. The average time to recurrence in these 3 eyes was 18 months. Average length of follow-up was 24.5 months for all subjects. Conclusion: Liquid nitrogen cryotherapy may be an effective surgical alternative in the treatment of conjunctival lymphangiectasia. Cryotherapy may need to be repeated in some instances. PMID:20126499

  20. Electrically and Thermally Insulated Joint for Liquid Nitrogen Transfer

    DEFF Research Database (Denmark)

    Rasmussen, Carsten; Jensen, Kim Høj; Holbøll, Joachim T.


    A prototype of a superconducting cable is currently under construction. The cable conductor is cooled by liquid nitrogen in order to obtain superconductivity. The peripheral cooling circuit is kept at ground potential. This requires a joint which insulates both electrically and thermally...

  1. Effect of liquid nitrogen storage time on the survival and ...

    African Journals Online (AJOL)

    Investigations were undertaken on the effect of liquid nitrogen (LN) storage time on survival and regeneration of somatic embryos of cocoa (Theobroma cacao l.). Somatic embryos from different cocoa genotypes (AMAZ 3-2, AMAZ 10-1, AMAZ 12, SIAL 93, and IMC 14) at 15.45% moisture content were cryopreserved in LN ...

  2. Absorption and oxidation of nitrogen oxide in ionic liquids

    DEFF Research Database (Denmark)

    Kunov-Kruse, Andreas Jonas; Thomassen, Peter Langelund; Riisager, Anders


    A new strategy for capturing nitrogen oxide, NO, from the gas phase is presented. Dilute NO gas is removed from the gas phase by ionic liquids under ambient conditions. The nitrate anion of the ionic liquid catalyzes the oxidation of NO to nitric acid by atmospheric oxygen in the presence of water...... investigations of the reaction and products are presented. The procedure reveals a new vision for removing the pollutant NO by absorption into a non-volatile liquid and converting it into a useful bulk chemical, that is, HNO3....

  3. Stability of liquid-nitrogen-jet laser-plasma targets (United States)

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


    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.

  4. Wicking of liquid nitrogen into superheated porous structures (United States)

    Grebenyuk, Yulia; Dreyer, Michael E.


    Evaporation in porous elements of liquid-vapor separation devices can affect the vapor-free cryogenic propellant delivery to spacecraft engines. On that account, the capillary transport of a cryogenic liquid subjected to evaporation needs to be understood and assessed. We investigate wicking of liquid nitrogen at saturation temperature into superheated porous media. A novel test facility was built to perform wicking experiments in a one-species system under non-isothermal conditions. A setup configuration enabled to define the sample superheat by its initial position in a stratified nitrogen vapor environment inside the cryostat. Simultaneous sample weight and temperature measurements indicated the wicking front velocity. The mass of the imbibed liquid nitrogen was determined varying the sample superheat, geometry and porous structure. To the author's extent of knowledge, these are the first wicking experiments performed with cryogenic fluids subjected to evaporation using the weight-time measurement technique. A one-dimensional macroscopic model describes the process theoretically. Results revealed that the liquid loss due to evaporation at high sample superheats leads to only a slight imbibition rate decrease. However, the imbibition rate can be greatly affected by the vapor flow created due to evaporation that counteracts the wicking front propagation.

  5. Study of laser-induced cavitation bubble in liquid nitrogen (United States)

    Takahashi, Toshimasa; Hisano, Eizo; Toyada, Kazuhiro; Maeno, Kazuo


    The behavior of Vapor bubbles in cryogenic liquid is regarded as a cryogenic and phase-changing flow field, where instability of bubble surface becomes larger than those in normal temperature liquid as water or oil, since the cryogenic liquid has characteristic feature of small latent heat, surface tension, and viscosity. The cavitation phenomena in cryogenic temperature range are regarded as vacitation in the liquid of near-boiling point. The cryogenic cavitation, however, have a significant influence on solid surfaces due to their weakness in cryogenic range. In this paper, shock waves discharged from a pulse-laser induced bubble and behavior of the bubble are experimentally investigated. Pulsed YAG laser is used to produce a bubble in cryogenic liquid nitrogen, and shock waves are visualized by using a digital still camera with schlieren method.

  6. Critical discharge of initially subcooled water through slits. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Amos, C N; Schrock, V E


    This report describes an experimental investigation into the critical flow of initially subcooled water through rectangular slits. The study of such flows is relevant to the prediction of leak flow rates from cracks in piping, or pressure vessels, which contain sufficient enthalpy that vaporization will occur if they are allowed to expand to the ambient pressure. Two new analytical models, which allow for the generation of a metastable liquid phase, are developed. Experimental results are compared with the predictions of both these new models and with a Fanno Homogeneous Equilibrium Model.

  7. Propagation of Local Bubble Parameters of Subcooled Boiling Flow in a Pressurized Vertical Annulus Channel

    Energy Technology Data Exchange (ETDEWEB)

    Chu, In-Cheol; Lee, Seung Jun; Youn, Young Jung; Park, Jong Kuk; Choi, Hae Seob; Euh, Dong Jin [KAERI, Daejeon (Korea, Republic of)


    CMFD (Computation Multi-Fluid Dynamics) tools have been being developed to simulate two-phase flow safety problems in nuclear reactor, including the precise prediction of local bubble parameters in subcooled boiling flow. However, a lot of complicated phenomena are encountered in the subcooled boiling flow such as bubble nucleation and departure, interfacial drag of bubbles, lateral migration of bubbles, bubble coalescence and break-up, and condensation of bubbles, and the constitutive models for these phenomena are not yet complete. As a result, it is a difficult task to predict the radial profile of bubble parameters and its propagation along the flow direction. Several experiments were performed to measure the local bubble parameters for the validation of the CMFD code analysis and improvement of the constitutive models of the subcooled boiling flow, and to enhance the fundamental understanding on the subcooled boiling flow. The information on the propagation of the local flow parameters along the flow direction was not provided because the measurements were conducted at the fixed elevation. In SUBO experiments, the radial profiles of local bubble parameters, liquid velocity and temperature were obtained for steam-water subcooled boiling flow in a vertical annulus. The local flow parameters were measured at six elevations along the flow direction. The pressure was in the range of 0.15 to 0.2 MPa. We have launched an experimental program to investigate quantify the local subcooled boiling flow structure under elevated pressure condition in order to provide high precision experimental data for thorough validation of up-to-date CMFD codes. In the present study, the first set of experimental data on the propagation of the radial profile of the bubble parameters was obtained for the subcooled boiling flow of R-134a in a pressurized vertical annulus channel. An experimental program was launched for an in-depth investigation of a subcooled boiling flow in an elevated

  8. Development of a mechanistic model for forced convection subcooled boiling (United States)

    Shaver, Dillon R.

    The focus of this work is on the formulation, implementation, and testing of a mechanistic model of subcooled boiling. Subcooled boiling is the process of vapor generation on a heated wall when the bulk liquid temperature is still below saturation. This is part of a larger effort by the US DoE's CASL project to apply advanced computational tools to the simulation of light water reactors. To support this effort, the formulation of the dispersed field model is described and a complete model of interfacial forces is formulated. The model has been implemented in the NPHASE-CMFD computer code with a K-epsilon model of turbulence. The interfacial force models are built on extensive work by other authors, and include novel formulations of the turbulent dispersion and lift forces. The complete model of interfacial forces is compared to experiments for adiabatic bubbly flows, including both steady-state and unsteady conditions. The same model is then applied to a transient gas/liquid flow in a complex geometry of fuel channels in a sodium fast reactor. Building on the foundation of the interfacial force model, a mechanistic model of forced-convection subcooled boiling is proposed. This model uses the heat flux partitioning concept and accounts for condensation of bubbles attached to the wall. This allows the model to capture the enhanced heat transfer associated with boiling before the point of net generation of vapor, a phenomenon consistent with existing experimental observations. The model is compared to four different experiments encompassing flows of light water, heavy water, and R12 at different pressures, in cylindrical channels, an internally heated annulus, and a rectangular channel. The experimental data includes axial and radial profiles of both liquid temperature and vapor volume fraction, and the agreement can be considered quite good. The complete model is then applied to simulations of subcooled boiling in nuclear reactor subchannels consistent with the

  9. Removal of nitrogen compounds from Brazilian petroleum samples by oxidation followed by liquid-liquid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Conceicao, L.; Pergher, S.B.C. [Universidade Regional Integrada do Alto Uruguai e das Misses (URI), Erechim, RS (Brazil). Dept. de Quimica], E-mail:; Oliveira, J.V. [Universidade Regional Integrada do Alto Uruguai e das Misses (URI), Erechim, RS (Brazil). Dept. de Engenharia dos Alimentos; Souza, W.F. [Petroleo Brasileiro S.A. (CENPES/PETROBRAS), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas


    This work reports liquid-liquid extraction of nitrogen compounds from oxidized and non-oxidized Brazilian petroleum samples. The experiments were accomplished in a laboratory-scale liquid-liquid apparatus in the temperature range of 303 K-323 K, using methanol, n-methyl-2-pyrrolidone (NMP) and N,Ndimethylformamide (DMF), and their mixtures as extraction solvents, employing solvent to sample volume ratios of 1:2, 1:1 and 2:1, exploring up to three separation stages. Results show that an increase in temperature, solvent to oil ratio, and number of equilibrium stages greatly improves the nitrogen removal from the oxidized sample (from 2600 to 200 ppm). The employed oxidation scheme is thus demonstrated to be an essential and efficient step of sample preparation for the selective liquid-liquid removal of nitrogen compounds. It is shown that the use of mixtures of DMF and NMP as well their use as co-solvents with methanol did not prove to be useful for selective nitrogen extraction since great oil losses were observed in the final process. (author)

  10. Successful vitrification of bovine immature oocyte using liquid helium instead of liquid nitrogen as cryogenic liquid. (United States)

    Yu, Xue-Li; Xu, Ya-Kun; Wu, Hua; Guo, Xian-Fei; Li, Xiao-Xia; Han, Wen-Xia; Li, Ying-Hua


    The objectives of this study were to compare the effectiveness of liquid helium (LHe) and liquid nitrogen (LN2) as cryogenic liquid for vitrification of bovine immature oocytes with open-pulled straw (OPS) system and determine the optimal cryoprotectant concentration of LHe vitrification. Cumulus oocyte complexes were divided into three groups, namely, untreated group (control), LN2 vitrified with OPS group, and LHe vitrified with OPS group. Oocyte survival was assessed by morphology, nuclear maturation, and developmental capability. Results indicated that the rates of normal morphology, maturation, cleavage, and blastocyst (89.3%, 52.8%, 42.7%, and 10.1%, respectively) in the LHe-vitrified group were all higher than those (79.3%, 43.4%, 34.1%, and 4.7%) in the LN2-vitrified group (P vitrification solutions (EDS30, EDS35, EDS40, EDS45, and EDS50) in LHe vitrification for bovine immature oocytes vitrification were examined. No difference was found in the rates of morphologically normal oocytes among the EDS30 (87.9%), EDS35 (90.1%), EDS40 (89.4%), and EDS45 (87.2%) groups (P > 0.05). The maturation rate of the EDS35 group (65.0%) was higher than those of the EDS30 (51.3%), EDS40 (50.1%), EDS45 (52.1%), and EDS50 groups (36.9%; P vitrification of bovine immature oocytes, and it is more efficient than LN2-vitrified oocytes in terms of blastocyst production. EDS35 was the optimal cryoprotectant agent combination for LHe vitrification in this study. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Numerical simulation of bubble behavior in subcooled flow boiling under velocity and temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Bahreini, Mohammad, E-mail:; Ramiar, Abas, E-mail:; Ranjbar, Ali Akbar, E-mail:


    Highlights: • Condensing bubble is numerically investigated using VOF model in OpenFOAM package. • Bubble mass reduces as it goes through condensation and achieves higher velocities. • At a certain time the slope of changing bubble diameter with time, varies suddenly. • Larger bubbles experience more lateral migration to higher velocity regions. • Bubbles migrate back to a lower velocity region for higher liquid subcooling rates. - Abstract: In this paper, numerical simulation of the bubble condensation in the subcooled boiling flow is performed. The interface between two-phase is tracked via the volume of fluid (VOF) method with continuous surface force (CSF) model, implemented in the open source OpenFOAM CFD package. In order to simulate the condensing bubble with the OpenFOAM code, the original energy equation and mass transfer model for phase change have been modified and a new solver is developed. The Newtonian flow is solved using the finite volume scheme based on the pressure implicit with splitting of operators (PISO) algorithm. Comparison of the simulation results with previous experimental data revealed that the model predicted well the behavior of the actual condensing bubble. The bubble lifetime is almost proportional to bubble initial size and is prolonged by increasing the system pressure. In addition, the initial bubble size, subcooling of liquid and velocity gradient play an important role in the bubble deformation behavior. Velocity gradient makes the bubble move to the higher velocity region and the subcooling rate makes it to move back to the lower velocity region.

  12. Liquid nitrogen cooling considerations of the Compact Ignition Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Dabiri, A.E.


    A simple model was developed to estimate the cooldown time between pulses of toroidal field (TF) coils of the Compact Ignition Tokamak (CIT) using liquid nitrogen. Good agreement was obtained between the analysis results and those measured in the early fusion experimental devices. A cooldown time of about 1 h would reduce the TF coil temperature to about 80 K. An R and D experimental program is required to determine the actual cooldown time between pulses, an issue in the conceptual design of the CIT.

  13. Relative Efficacy of Liquid Nitrogen Fertilizers in Dryland Spring Wheat

    Directory of Open Access Journals (Sweden)

    Olga S. Walsh


    Full Text Available The study was conducted in 2012 and 2013 at three locations in North Central and Western Montana (total of 6 site-years to evaluate the relative efficacy of three liquid nitrogen (N fertilizer sources, urea ammonium nitrate (UAN, 32-0-0, liquid urea (LU, 21-0-0, and High NRGN (HNRGN, 27-0-0-1S, in spring wheat (Triticum aestivum L.. In addition to at-seeding urea application at 90 kg N ha−1 to all treatments (except for the unfertilized check plot, the liquid fertilizers were applied utilizing an all-terrain vehicle- (ATV- mounted stream-bar equipped sprayer at a rate of 45 kg N ha−1 at Feekes 5 growth stage (early tillering. Three dilution ratios of fertilizer to water were accessed: 100/0 (undiluted, 66/33, and 33/66. The effects of N source and the dilution ratio (fertilizer/water on N uptake (NUp, N use efficiency (NUE, spring wheat grain yield (GY, grain protein (GP content, and protein yield (PY were assessed. The dilution ratios had no effect on GY, GP, PY, NUp, and NUE at any of the site-years in this study. Taking into account agronomic and economic factors, LU can be recommended as the most suitable liquid N fertilizer source for spring wheat cropping systems of the Northern Great Plains.

  14. Cryopreservation of dammar (Agathis damara Salisb. seeds in liquid nitrogen

    Directory of Open Access Journals (Sweden)



    Full Text Available Dammar (Agathis damara seeds categorized as an intermediate seeds since their viability tend to decrease when subjected to storage more than 2 weeks conventionally. Storage period of seeds could be prolonged when the seeds cryopreserved in liquid nitrogen since the metabolism of the cells could be minimized without loss of viability. The objective of the study was to identify suitable vitritification method for dammar storage seeds. Seed water content was decreased gradually from initial water content (28.48% as a control using desiccators and vacuum method. Vitrification solution (PVS2 containing glycerol 30%, ethylene glycol 15% and dimethylsulfoxide (DMSO 15% in 0.4M sucrose solution was used as a cryoprotectant of peeled or unpeeled dammar seeds during freezing process. The samples were soaked in PVS2 for 1 hour followed by exposure to liquid nitrogen in cryotube for 1 hour. The samples were then thawed in water bath at 28°C for 1 hour prior to germination in IPB-78 germinator with UDK and UKdDp germination methods. Results showed that the highest viability of cryopreserved dammar seeds (22.32% moisture content was 100% obtained from those germinated with UKdDp method. A negative effect of cryoprotectant was occurred in both peeled and unpeeled seeds cryopreserved for 1 hour. However, it was effective for seeds cryopreserved for 4 weeks which indicate the possibility to preserve for a longer period in the future.

  15. High Energy Cutting and Stripping Utilizing Liquid Nitrogen (United States)

    Hume, Howard; Noah, Donald E.; Hayes, Paul W.


    The Aerospace Industry has endeavored for decades to develop hybrid materials that withstand the rigors of mechanized flight both within our atmosphere and beyond. The development of these high performance materials has led to the need for environmentally friendly technologies for material re-work and removal. The NitroJet(TM) is a fluid jet technology that represents an evolution of the widely used, large-scale water jet fluid jet technology. It involves the amalgamation of fluid jet technology and cryogenics technology to create a new capability that is applicable where water jet or abrasive jet (water jet plus entrained abrasive) are not suitable or acceptable because of technical constraints such as process or materials compatibility, environmental concerns and aesthetic or legal requirements. The NitroJet(TM) uses ultra high-pressure nitrogen to cut materials, strip numerous types of coatings such as paint or powder coating, clean surfaces and profile metals. Liquid nitrogen (LN2) is used as the feed stream and is pressurized in two stages. The first stage pressurizes sub cooled LN2 to an intermediate pressure of between 15,000 and 20,000 psi at which point the temperature of the LN2 is about -250 F. The discharge from this stage is then introduced as feed to a dual intensifier system, which boosts the pressure from 15,000 - 20,000 psi up to the maximum operating pressure of 55,000 psi. A temperature of about -220 F is achieved at which point the nitrogen is supercritical. In this condition the nitrogen cuts, strips and abrades much like ultra high-pressure water would but without any residual liquid to collect, remove or be contaminated. Once the nitrogen has performed its function it harmlessly flashes back into the atmosphere as pure nitrogen gas. The system uses heat exchangers to control and modify the temperature of the various intake and discharge nitrogen streams. Since the system is hydraulically operated, discharge pressures can be easily varied over

  16. Theoretical prediction method of subcooled flow boiling CHF

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Young Min; Chang, Soon Heung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    A theoretical critical heat flux (CHF ) model, based on lateral bubble coalescence on the heated wall, is proposed to predict the subcooled flow boiling CHF in a uniformly heated vertical tube. The model is based on the concept that a single layer of bubbles contacted to the heated wall prevents a bulk liquid from reaching the wall at near CHF condition. Comparisons between the model predictions and experimental data result in satisfactory agreement within less than 9.73% root-mean-square error by the appropriate choice of the critical void fraction in the bubbly layer. The present model shows comparable performance with the CHF look-up table of Groeneveld et al.. 28 refs., 11 figs., 1 tab. (Author)

  17. D0 Silicon Upgrade: Liquid Nitrogen Valve Sizing for D-Zero Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, Russ; /Fermilab


    There were 5 control valves and 2 manual valves for the liquid nitrogen distribution system that needed to be sized and procured for the upgrade. This engineering note documents the calculations done to properly size these valves. A table summarizes the valve choices. The raw calculations are attached as an appendix. The calculations jump around a bit. No effort was made to re-organize or rewrite them for the reader. The sizing calcs. on Pages 1 through 4 were first pass calcs. based on pure liquid to the valves with no attention to flashing/choking. The calcs on pages 5 through 8 then refine the calculations by considering the LN2 to the valve inlets to be two phase with quality of 0.032. This is a real situation if the LN2 subcooler is out of service for use as a He cooldown heat exchanger. Also, flashing would occur for this situation and is taken into account. The end result of this refinement pushed the Cv values up by about a factor of 3 over the initial calcs. of pages 1 through 4. The results of the refined (correct) calculations pages 5 through 8 appear in the table above. The required operating Cv's are smaller than commercially available LN2 control valves. Therefore it has been decided to use Fermilab Saver type control valve assemblies with the valve bullet Cv1s listed above. The bullets are 100: 1 equal percentage types and provide better control at the lower percentage of valve Cv values. See flow characteristic data and curve for these valves in appendix B. The manual valves will be commercially purchased, probably a Cryolab model CV3-84-5WPG2 or CV8-84-5WPG2 or CVI model V-1060-050-VJ. Pages 8-10 calculate a minimum required cooldown flowrate as referenced in Cryogenic Systems by Barron. This was done to be sure the valves and piping system did not choke the warm flow so much that cooldown could not be achieved. The minimum mass flow rate needed for a simultaneous, serial cooldown of the refrigerator, solenoid and VLPC system was 6.4 g/s. This

  18. Liquid Nitrogen Temperature Operation of a Switching Power Converter (United States)

    Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.


    The performance of a 42/28 V, 175 W, 50 kHz pulse-width modulated buck dc/dc switching power converter at liquid nitrogen temperature (LNT) is compared with room temperature operation. The power circuit as well as the control circuit of the converter, designed with commercially available components, were operated at LNT and resulted in a slight improvement in converter efficiency. The improvement in power MOSFET operation was offset by deteriorating performance of the output diode rectifier at LNT. Performance of the converter could be further improved at low temperatures by using only power MOSFET's as switches. The use of a resonant topology will further improve the circuit performance by reducing the switching noise and loss.

  19. Heat and mass transfer of liquid nitrogen in coal porous media (United States)

    Lang, Lu; Chengyun, Xin; Xinyu, Liu


    Liquid nitrogen has been working as an important medium in fire extinguishing and prevention, due to its efficiency in oxygen exclusion and heat removal. Such a technique is especially crucial for coal industry in China. We built a tunnel model with a temperature monitor system (with 36 thermocouples installed) to experimentally study heat and mass transfer of liquid nitrogen in non-homogeneous coal porous media (CPM), and expected to optimize parameters of liquid nitrogen injection in engineering applications. Results indicate that injection location and amount of liquid nitrogen, together with air leakage, significantly affect temperature distribution in CPM, and non-equilibrium heat inside and outside of coal particles. The injection position of liquid nitrogen determines locations of the lowest CPM temperature and liquid nitrogen residual. In the deeper coal bed, coal particles take longer time to reach thermal equilibrium between their surface and inside. Air leakage accelerates temperature increase at the bottom of the coal bed, which is a major reason leading to fire prevention inefficiency. Measurement fluctuation of CPM temperature may be caused by incomplete contact of coal particles with liquid nitrogen flowing in the coal bed. Moreover, the secondary temperature drop (STD) happens and grows with the more injection of liquid nitrogen, and the STD phenomenon is explained through temperature distributions at different locations.

  20. Homogeneous nucleation in liquid nitrogen at negative pressures

    Energy Technology Data Exchange (ETDEWEB)

    Baidakov, V. G., E-mail:; Vinogradov, V. E.; Pavlov, P. A. [Russian Academy of Sciences, Institute of Thermal Physics, Ural Branch (Russian Federation)


    The kinetics of spontaneous cavitation in liquid nitrogen at positive and negative pressures has been studied in a tension wave formed by a compression pulse reflected from the liquid–vapor interface on a thin platinum wire heated by a current pulse. The limiting tensile stresses (Δp = p{sub s}–p, where p{sub s} is the saturation pressure), the corresponding bubble nucleation frequencies J (10{sup 20}–10{sup 22} s{sup –1} m{sup –3}), and temperature induced nucleation frequency growth rate G{sub T} = dlnJ/dT have been experimentally determined. At T = 90 K, the limiting tensile stress was Δp = 8.3 MPa, which was 4.9 MPa lower than the value corresponding to the boundary of thermodynamic stability of the liquid phase (spinodal). The measurement results were compared to classical (homogeneous) nucleation theory (CNT) with and without neglect of the dependence of the surface tension of critical bubbles on their dimensions. In the latter case, the properties of new phase nuclei were described in terms of the Van der Waals theory of capillarity. The experimental data agree well with the CNT theory when it takes into account the “size effect.”.

  1. Fast Conversion of Ionic Liquids and Poly(Ionic Liquids into Porous Nitrogen-Doped Carbons in Air

    Directory of Open Access Journals (Sweden)

    Yongjun Men


    Full Text Available Ionic liquids and poly(ionic liquids have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m2/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection.

  2. Liquid nitrogen cooling in IR thermography applied to steel specimen (United States)

    Lei, L.; Ferrarini, G.; Bortolin, A.; Cadelano, G.; Bison, P.; Maldague, X.


    Pulsed Thermography (PT) is one of the most common methods in Active Thermography procedures of the Thermography for NDT & E (Nondestructive Testing & Evaluation), due to the rapidity and convenience of this inspection technique. Flashes or lamps are often used to heat the samples in the traditional PT. This paper mainly explores exactly the opposite external stimulation in IR Thermography: cooling instead of heating. A steel sample with flat-bottom holes of different depths and sizes has been tested. Liquid nitrogen (LN2) is sprinkled on the surface of the specimen and the whole process is captured by a thermal camera. To obtain a good comparison, two other classic NDT techniques, Pulsed Thermography and Lock-In Thermography, are also employed. In particular, the Lock-in method is implemented with three different frequencies. In the image processing procedure, the Principal Component Thermography (PCT) method has been performed on all thermal images. For Lock-In results, both Phase and Amplitude images are generated by Fast Fourier Transform (FFT). Results show that all techniques presented part of the defects while the LN2 technique displays the flaws only at the beginning of the test. Moreover, a binary threshold post-processing is applied to the thermal images, and by comparing these images to a binary map of the location of the defects, the corresponding Receiver Operating Characteristic (ROC) curves are established and discussed. A comparison of the results indicates that the better ROC curve is obtained using the Flash technique with PCT processing method.

  3. Connection for transfer of Liquid Nitrogen from High Voltage to ground potential

    DEFF Research Database (Denmark)

    Rasmussen, Claus Nygaard; Hansen, Finn; Willén, Dag


    In order to operate a superconducting cable conductor it must be kept at a cryogenic temperature (e.g. using liquid nitrogen). The superconducting cable conductor is at high voltage and the cooling equipment is kept at ground potential. This requires a thermally insulating connection that is also...... properties and withstand towards high-pressure liquid nitrogen. The length per joint is approximately 900 mm, including a Johnstoncoupling. The joints are tested in a closed liquid nitrogen circuit, with a pressure of up to 10 bars. The rated voltage of the cable system is 36 kV (phase-phase)....


    Santo, M V; Sansinena, M; Chirife, J; Zaritzky, N


    The use of mathematical models describing heat transfer during the freezing process is useful for the improvement of cryopreservation protocols. A widespread practice for cryopreservation of spermatozoa of domestic animal species consists of suspending plastic straws in nitrogen vapor before plunging into liquid nitrogen. Knowledge of surface heat transfer coefficient (h) is mandatory for computational modelling; however, h values for nitrogen vapor are not available. In the present study, surface heat transfer coefficients for plastic French straws immersed in nitrogen vapor over liquid nitrogen was determined; vertical and horizontal positions were considered. Heat transfer coefficients were determined from the measurement of time-temperature curves and from numerical solution of heat transfer partial differential equation under transient conditions using finite elements. The h values experimentally obtained for horizontal and vertically placed straws were compared to those calculated using correlations based on the Nusselt number for natural convection. For horizontal straws the average obtained value was h=12.5 ± 1.2 W m(2) K and in the case of vertical straws h=16 ± 2.48 W m(2) K. The numerical simulation validated against experimental measurements, combined with accurate h values provides a reliable tool for the prediction of freezing curves of semen-filled straws immersed in nitrogen vapor. The present study contributes to the understanding of the cryopreservation techniques for sperm freezing based on engineering concepts, improving the cooling protocols and the manipulation of the straws.

  5. On the influence of water subcooling and melt jet parameters on debris formation

    Energy Technology Data Exchange (ETDEWEB)

    Manickam, Louis, E-mail:; Kudinov, Pavel; Ma, Weimin; Bechta, Sevostian; Grishchenko, Dmitry


    Highlights: • Melt and water configuration effects on debris formation is studied experimentally. • Melt superheat and water subcooling are most influential compared to jet size. • Melt-water configuration and material properties influence particle fracture rate. • Results are compared with large scale experiments to study effect of spatial scales. - Abstract: Breakup of melt jet and formation of a porous debris bed at the base-mat of a flooded reactor cavity is expected during the late stages of a severe accident in light water reactors. Debris bed coolability is determined by the bed properties including particle size, morphology, bed height and shape as well as decay heat. Therefore understanding of the debris formation phenomena is important for assessment of debris bed coolability. A series of experiments was conducted in MISTEE-Jet facility by discharging binary-oxide mixtures of WO{sub 3}–Bi{sub 2}O{sub 3} and WO{sub 3}–ZrO{sub 2} into water in order to investigate properties of resulting debris. The effect of water subcooling, nozzle diameter and melt superheat was addressed in the tests. Experimental results reveal significant influence of water subcooling and melt superheat on debris size and morphology. Significant differences in size and morphology of the debris at different melt release conditions is attributed to the competition between hydrodynamic fragmentation of liquid melt and thermal fracture of the solidifying melt droplets. The particle fracture rate increases with increased subcooling. Further the results are compared with the data from larger scale experiments to discern the effects of spatial scales. The present work provides data that can be useful for validation of the codes used for the prediction of debris formation phenomena.

  6. Liquid Nitrogen (-196°C effect under pollen of some cultured or ornamental species

    Directory of Open Access Journals (Sweden)

    Sabina GLIGOR


    Full Text Available The criopreservation involve the stock of the vegetal material at low temperatures (-196°C in liquid nitrogen, in thermal conditions in which the division of cells and metabolic processes slow down, thus that the samplings may be conserved for long periods without suffering any genetic modifications. This stock technique is applied till present only on 80 vegetal species, keeping their seeds and vitrocultures preponderantly; researches were made regarding the maintenance of pollen in liquid nitrogen.The mature pollen, able to resist a higher degree of desiccation, may be conserved at low temperatures, without criopreservation. It was made researches on criopreservation of rise, maize, wheat, roses, sun flower and soy pollen. Our study purpose was to follow the impact of liquid nitrogen (-196°C about on viability of some cultured and ornamental species. The designed time of criopreservation it was 30 minutes and 7 days, using the TTC (tripheniltetrazole chloride method which allows testing the viability of vegetal material based on dehydrogenase activity.It was observed at Petunia hybrida species, that the pollen viability was low - in relevance with the witness represented from the pollen which was not resigned to the nitrogen liquid treatment - between percentage limits of 3.5-8%, in the case when the vegetal material was submersed 30 minutes in liquid nitrogen and 7.5-14.5% 7 days at (-196°C. The submersing of Nicotiana alata var. grandiflora species at 7 days, determined a low viability with 11.53%. The following two studied species Cucurbita and Hosta were proved to be the most resistant at submersing and maintenance in liquid nitrogen. The most affected pollen was Campsis radicans species. At Datura stramonium species was observed 2.59% a low viability of pollen, after 30 minutes of liquid nitrogen treatment, was 19.56%, after 7 days of submersing, the most pollen granules losing completely their viability.

  7. Strength analysis of CARR-CNS with crescent-shape moderator cell and helium sub-cooling jacket covering cell (United States)

    Yu, Qingfeng; Feng, Quanke; Kawai, Takeshi; Shen, Feng; Yuan, Luzheng; Cheng, Liang


    The new type of the moderator cell was developed for the cold neutron source (CNS) of the China Advanced Research Reactor (CARR) which is now being constructed at the China Institute of Atomic Energy in Beijing. A crescent-shape moderator cell covered by the helium sub-cooling jacket is adopted. The structure of the moderator cell is optimized by the stress FEM analysis. A crescent-shape would help to increase the volume of the moderator cell for fitting it to the four cold neutron guide tubes, even if liquid hydrogen, not liquid deuterium, was used as a cold moderator. The helium sub-cooling jacket covering the moderator cell removes the nuclear heating of the outer shell wall of the cell. It contributes to reduce the void fraction of liquid hydrogen in the outer shell of the moderator cell. Such a type of a moderator cell is suitable for the CNS with higher nuclear heating. The cold helium gas flows down first into the helium sub-cooling jacket and then flows up to the condenser. The theory of the self-regulation suitable to the thermo-siphon type of the CNS is also applicable and validated.

  8. Solutions for Liquid Nitrogen Pre-Cooling in Helium Refrigeration Cycles

    CERN Document Server

    Wagner, U


    Pre-cooling of helium by means of liquid nitrogen is the oldest and one of the most common process features used in helium liquefiers and refrigerators. Its two principle tasks are to allow or increase the rate of pure liquefaction, and to permit the initial cool-down of large masses to about 80 K. Several arrangements for the pre-cooling process are possible depending on the desired application. Each arrangement has its proper advantages and drawbacks. The aim of this paper is to review the possible process solutions for liquid nitrogen pre-cooling and their particularities.

  9. The Influence Of The Temperature Of Liquid Nitrogen On The Physical Properties Of Powder Magnetic Composites

    Directory of Open Access Journals (Sweden)

    Kapelski D.


    Full Text Available The paper presents the physical properties of soft magnetic iron composites and Nd-Fe-B bonded permanent magnets measured at room temperature and at liquid nitrogen. The objective of research was a determination of influence of liquid nitrogen temperature on the magnetic properties, resistivity and mechanical properties of different powder magnetic materials. Research was carried out for three powder materials: soft magnetic, i.e. Somaloy 700, AncorLam and hard magnetic powder MQP-B used for production of bonded magnets. Composite specimens were prepared by compression moulding technology.

  10. Treatment of gingival physiologic pigmentation in adolescents by liquid nitrogen cryosurgery: 24-month follow-up. (United States)

    Shirazi, Alireza Sarraf; Moeintaghavi, Amir; Khorakian, Fatemeh; Talebi, Maryam


    Although gingival pigmentation is physiologic in most cases, esthetic concerns regarding "black gums" are common among adolescents. Numerous procedures have been suggested to treat this problem. The aim of this study was to evaluate the efficacy of cryosurgery with liquid nitrogen for the removal of physiologic gingival pigmentation (PGP) in adolescents. Melanin pigmentation of the anterior segments in 15 patients was treated using liquid nitrogen. Standard digital photographs were taken preoperatively and at 3, 12, and 24 months postoperatively. Photographs were analyzed digitally and showed significant differences in gingival color between the preoperative and postoperative follow-ups. Cryosurgery successfully removed PGP in adolescents.

  11. Interferometric and numerical study of the temperature field in the boundary layer and heat transfer in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Lucic, Anita; Emans, Maximilian; Mayinger, Franz; Zenger, Christoph


    An interferometric study and a numerical simulation are presented of the combined process of the bulk turbulent convection and the dynamic of a vapor bubble which is formed in the superheated boundary layer of a subcooled flowing liquid, in order to determine the heat transfer to the flowing subcooled liquid. In this investigation focus has been given on a single vapor bubble at a defined cavity site to provide reproducible conditions. In the experimental study single bubbles were generated at a single artificial cavity by means of a CO{sub 2}-laser as a spot heater at a uniformly heated wall of a vertical rectangular channel with water as the test fluid. The experiments were performed at various degrees of subcooling and mass flow rates. The bubble growth and the temporal decrease of the bubble volume were captured by means of the high-speed cinematography. The thermal boundary layer and the temperature field at the phase-interface between fluid and bubble were visualized by means of the optical measurement method holographic interferometry with a high temporal and spatial resolution, and thus the local and temporal heat transfer could be quantified. The experimental results form a significant data basis for the description of the mean as well as the local heat transfer as a function of the flow conditions. According to the experimental configuration and the obtained data the numerical simulations were performed. A numerical method has been developed to simulate the influence of single bubbles on the surrounding fluid which is based on a Lagrangian approach to describe the motion of the bubbles. The method is coupled to a large-eddy simulations by the body force term which is locally evaluated based on the density field. The obtained experimental data correspond well with the numerical predictions, both of which demonstrate the thermo- and fluiddynamic characteristics of the interaction between the vapor bubble and the subcooled liquid.

  12. Simulation methods of rocket fuel refrigerating with liquid nitrogen and intermediate heat carrier

    Directory of Open Access Journals (Sweden)

    O. E. Denisov


    Full Text Available Temperature preparation of liquid propellant components (LPC before fueling the tanks of rocket and space technology is the one of the operations performed by ground technological complexes on cosmodromes. Refrigeration of high-boiling LPC is needed to increase its density and to create cold reserve for compensation of heat flows existing during fueling and prelaunch operations of space rockets.The method and results of simulation of LPC refrigeration in the recuperative heat exchangers with heat carrier which is refrigerated by-turn with liquid nitrogen sparging. The refrigerating system consists of two tanks (for the chilled coolant and LPC, LPC and heat carrier circulation loops with heat exchanger and system of heat carrier refrigeration in its tank with bubbler. Application of intermediate heat carrier between LPC and liquid nitrogen allows to avoid LPC crystallization on cold surfaces of the heat exchanger.Simulation of such systems performance is necessary to determine its basic design and functional parameters ensuring effective refrigerating of liquid propellant components, time and the amount of liquid nitrogen spent on refrigeration operation. Creating a simulator is quite complicated because of the need to take into consideration many different heat exchange processes occurring in the system. Also, to determine the influence of various parameters on occurring processes it is necessary to take into consideration the dependence of all heat exchange parameters on each other: heat emission coefficients, heat transfer coefficients, heat flow amounts, etc.The paper offers an overview of 10 references to foreign and Russian publications on separate issues and processes occurring in liquids refrigerating, including LPC refrigeration with liquid nitrogen. Concluded the need to define the LPC refrigerating conditions to minimize cost of liquid nitrogen. The experimental data presented in these publications is conformed with the application of

  13. Microbial contamination of embryos and semen during long term banking in liquid nitrogen. (United States)

    Bielanski, A; Bergeron, H; Lau, P C K; Devenish, J


    We report on microbial contamination of embryos and semen cryopreserved in sealed plastic straws and stored for 6-35 years in liquid nitrogen. There were 32 bacterial and 1 fungal species identified from randomly drawn liquid nitrogen, frozen semen, and embryos samples stored in 8 commercial and 8 research facility liquid nitrogen (LN) tanks. The identified bacteria represented commensal or environmental microorganisms and some, such as Escherichia coli, were potential or opportunistic pathogens for humans and animals. Stenotrophomonas maltophilia was the most common contaminant identified from the samples and was further shown to significantly suppress fertilization and embryonic development in vitro. Analysis of the strains by pulsed field gel electrophoresis revealed restriction patterns with no relatedness indicating that there was no apparent cross-contamination of S. maltophilia strains between the germplasm and liquid nitrogen samples. In addition, no transmission of bovine viral diarrhea virus (BVDV) and bovine herpesvirus-1 (BHV-1) from infected semen and embryos straws to clean germplasm stored in the same LN tanks or LN was detected.

  14. Nitrogen Fertilizer Replacement Value of Concentrated Liquid Fraction of Separated Pig Slurry Applied to Grassland

    NARCIS (Netherlands)

    Middelkoop, Van J.C.; Holshof, G.


    Seven grassland experiments on sandy and clay soils were performed during a period of 4 years to estimate the nitrogen (N) fertilizer replacement value (NFRV) of concentrated liquid fractions of separated pig slurry (mineral concentrate: MC). The risk of nitrate leaching when applying MC was

  15. Non liquid nitrogen-based-method for isolation of DNA from ...

    African Journals Online (AJOL)

    A simple, efficient, reliable and cost-effective method for isolation of total genomic DNA from fungi, suitable for polymerase chain reaction (PCR) amplification and other molecular applications was described. The main advantages of the method are: (1) does not require the use of liquid nitrogen for preparation of fungi DNA; ...

  16. Fluorescence action spectra of algae and bean leaves at room and at liquid nitrogen temperatures

    NARCIS (Netherlands)

    Goedheer, J.C.


    Fluorescence action spectra were determined, both at room temperature and at liquid nitrogen temperature, with various blue-green, red and green algae, and greening bean leaves. The action spectra of algae were established with samples of low light absorption as well as dense

  17. Cryopreservation of citrus seed via dehydration followed by immersion in liquid nitrogen (United States)

    An important method for plant germplasm conservation is offered by a biotechnology-based approach of cryopreservation. Cryopreservation refers to the storage of plant material at ultralow temperatures in liquid nitrogen. A procedure for cryopreservation of polyembryonic seeds was improved for select...

  18. Effects of liquid nitrogen fertilizer and Benzyl Amino Purine (BAP) on ...

    African Journals Online (AJOL)

    The effects of combined treatment of liquid nitrogen fertilizer and benzyl amino purine (BAP) was studied on mineral elements (Magnesium, Phosphorus, Potassium, Calcium, sodium, iron and Manganese) and lipid content in relation to senescence. The experimental site for this study was situated at the botanical garden of ...

  19. Nitrogen losses and chemical parameters during co-composting of solid wastes and liquid pig manure. (United States)

    Vázquez, M A; de la Varga, D; Plana, R; Soto, M


    The aim of this research was to study nitrogen losses during the treatment of the liquid fraction (LF) of pig manure by co-composting and to establish the best conditions for compost production with higher nitrogen and low heavy metal contents. Windrows were constituted with the solid fraction (SF) of pig manure, different organic waste (SF of pig manure, sawdust and grape bagasse) as co-substrate and Populus spp. wood chips as bulking material and watered intensely with the LF. Results show that nitrogen losses ranged from 30% to 66% of initial nitrogen and were mainly governed by substrate to bulking mass ratio and liquid fraction to substrate (LF/S) ratio, and only secondarily by operational parameters. Nitrogen losses decreased from 55-65% at low LF/S ratios (1.7-1.9 m3/t total solids (TS)) to 30-39% at high LF/S ratios (4.4-4.7 m3/t TS). Therefore, integrating the LF in the composting process at high LF/S ratios favoured nitrogen recovery and conservation. Nitrogen in the fine fraction (ranging from 27% to 48% of initial nitrogen) was governed by operational parameters, namely pH and temperature. Final compost showed low content in most heavy metals, but Zn was higher than the limits for compost use in agriculture. Zn content in the obtained compost varied from 1863 to 3269 mg/kg dm, depending on several factors. The options for obtaining better quality composts from the LF of pig manure are selecting co-substrates with low heavy metal content and using them instead of the SF of pig manure.

  20. Direct Numerical Simulation and Visualization of Subcooled Pool Boiling

    Directory of Open Access Journals (Sweden)

    Tomoaki Kunugi


    Full Text Available A direct numerical simulation of the boiling phenomena is one of the promising approaches in order to clarify their heat transfer characteristics and discuss the mechanism. During these decades, many DNS procedures have been developed according to the recent high performance computers and computational technologies. In this paper, the state of the art of direct numerical simulation of the pool boiling phenomena during mostly two decades is briefly summarized at first, and then the nonempirical boiling and condensation model proposed by the authors is introduced into the MARS (MultiInterface Advection and Reconstruction Solver developed by the authors. On the other hand, in order to clarify the boiling bubble behaviors under the subcooled conditions, the subcooled pool boiling experiments are also performed by using a high speed and high spatial resolution camera with a highly magnified telescope. Resulting from the numerical simulations of the subcooled pool boiling phenomena, the numerical results obtained by the MARS are validated by being compared to the experimental ones and the existing analytical solutions. The numerical results regarding the time evolution of the boiling bubble departure process under the subcooled conditions show a very good agreement with the experimental results. In conclusion, it can be said that the proposed nonempirical boiling and condensation model combined with the MARS has been validated.

  1. Mechanisms of graphene exfoliation under the action of femtosecond laser radiation in liquid nitrogen (United States)

    Khorkov, K. S.; Kochuev, D. A.; Ilin, V. A.; Chkalov, R. V.; Prokoshev, V. G.; Arakelian, S. M.


    The processes of graphene structures formation under the action of the femtosecond laser radiation on carbon samples in liquid nitrogen are discussed. Mechanisms of graphene sheets exfoliation are proposed depending on the power density of the laser radiation: in the first case, the separation occurs due to the volumetric expansion during heating the region occupied by nitrogen molecules; at a laser radiation energy exceeding the ablation threshold, the surface of graphite begins to breakdown in the region of the action, followed by separation into graphene layers.

  2. Cryopreservation of human sperm: efficacy and use of a new nitrogen-free controlled rate freezer versus liquid nitrogen vapour freezing. (United States)

    Creemers, E; Nijs, M; Vanheusden, E; Ombelet, W


    Preservation of spermatozoa is an important aspect of assisted reproductive medicine. The aim of this study was to investigate the efficacy and use of a recently developed liquid nitrogen and cryogen-free controlled rate freezer and this compared with the classical liquid nitrogen vapour freezing method for the cryopreservation of human spermatozoa. Ten patients entering the IVF programme donated semen samples for the study. Samples were analysed according to the World Health Organization guidelines. No significant difference in total sperm motility after freeze-thawing between the new technique and classical technique was demonstrated. The advantage of the new freezing technique is that it uses no liquid nitrogen during the freezing process, hence being safer to use and clean room compatible. Investment costs are higher for the apparatus but running costs are only 1% in comparison with classical liquid nitrogen freezing. In conclusion, post-thaw motility of samples frozen with the classical liquid nitrogen vapour technique was comparable with samples frozen with the new nitrogen-free freezing technique. This latter technique can thus be a very useful asset to the sperm cryopreservation laboratory. © 2011 Blackwell Verlag GmbH.

  3. Effect of hydrostatic pressure on the stress strain behavior of potassium and lead at liquid nitrogen temperature

    Energy Technology Data Exchange (ETDEWEB)

    Chua, J.O.


    The hypothesis that at low homologous temperature, the pressure effect on the yielding of metals is closely related to the effect of pressure on the elastic constants was tested. An apparatus in which tension tests can be made at liquid nitrogen temperature and high hydrostatic pressure was designed and constructed. Tension tests for potassium and lead were carried out at liquid nitrogen temperature and as a function of pressure up to 5.15 kbars. The results show that the effect of hydrostatic pressure was to raise the stress strain curves of both potassium and lead at liquid nitrogen temperature.

  4. Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

    DEFF Research Database (Denmark)

    Thieme, Lisa; Graeber, Daniel; Kaupenjohann, Martin


    -freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow, litter leachate and soil solution samples were analyzed for DOC......Freezing can affect concentrations and spectroscopic properties of dissolved organic matter (DOM) in water samples. Nevertheless, water samples are regularly frozen for sample preservation. In this study we tested the effect of different freezing methods (standard freezing at −18 °C and fast...... concentrations, UV-vis absorption and fluorescence excitation–emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at −18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax...

  5. Two-Dimensional Metrology with Flatbed Scanners at Room and Liquid Nitrogen Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.; Grau Malonda, A. [CIEMAT. Madrid (Spain)


    We study the capability of the commercial flatbed scanner as a measuring instrument of two-coordinate sample both at room and liquid nitrogen temperatures. We describes simple procedure to calibrate the scanner, and the most adequate standard configuration to carry out the measurements. To illustrate the procedure, we measure the relative positions of the conductors in a cross-section of a superconducting magnet of CERN. (Author) 8 refs.

  6. Comparison between mechanical freezer and conventional freezing using liquid nitrogen in normozoospermia. (United States)

    Rahana, A R; Ng, S P; Leong, C F; Rahimah, M D


    This study evaluated the effect of human semen cryopreservation using an ultra-low temperature technique with a mechanical freezer at -85°C as an alternative method to the conventional liquid nitrogen technique at -196°C. This was a prospective experimental study conducted in the Medically Assisted Conception unit, Department of Obstetrics and Gynaecology, National University Hospital, Malaysia from January 1, 2006 to April 30, 2007. All normozoospermic semen samples were included in the study. The concentration, motility and percentage of intact DNA of each semen sample were assessed before and after freezing and thawing on Days 7 and 30 post freezing. Sperm cryopreservation at -85°C was comparable to the conventional liquid nitrogen technique for a period of up to 30 days in a normozoospermic sample. There was no statistical difference in concentration (Day 7 p-value is 0.1, Day 30 p-value is 0.2), motility (Day 7 p-value is 0.9, Day 30 p-value is 0.5) and proportion of intact DNA (Day 7 p-value is 0.1, Day 30 p-value is 0.2) between the ultra-low temperature technique and conventional liquid nitrogen cryopreservation at Days 7 and 30 post thawing. This study clearly demonstrates that short-term storage of sperm at -85°C could be a viable alternative to conventional liquid nitrogen cryopreservation at -196°C due to their comparable post-thaw results.

  7. Human platelets frozen with glycerol in liquid nitrogen: biological and clinical aspects. (United States)

    Herve, P; Potron, G; Droule, C; Beduchaud, M P; Masse, M; Coffe, C; Bosset, J F; Peters, A


    Platelets were frozen using glycerol (3% in plasma) as a cryoprotective agent, a rapid cooling rate, and liquid nitrogen for storage. The cryopreserved platelets were thawed at 42 C and infused without washing. The results indicate that the quality of the thawed platelets is equivalent to platelets stored for 24 to 48 hours at room temperature. The availability of HLA phenotyped leukocyte poor platelets can reduce the frequency of sensitization to strong antigens and provide clinically effective platelets for alloimmunized patients.

  8. Lightning impulse breakdown voltage of liquid nitrogen under the influence of heating (United States)

    Fink, S.; Noe, M.; Zwecker, V.; Leibfried, T.


    For application of high voltage superconducting apparatus liquid nitrogen is often not only used as coolant but also for electrical insulation. A temperature increase, e. g. during a quench of a fault current limiter, may cause a considerable decrease of the breakdown voltage within the apparatus. A cryostat was equipped with an adjustable sphere to plate electrode arrangement for the examination of the breakdown and withstand voltages of liquid nitrogen depending on the gap length. The sphere was connected to high voltage and the plate electrode was grounded. Standard lightning impulses till 360 kV were applied to the arrangement. First investigations with a non heatable plane for pressures till 0.3 MPa (absolute) showed no technical relevant gain by pressure increase especially for negative impulses. Hence the dielectric strength of liquid nitrogen in the heated case in comparison to the not heated mode was only examined at 0.1 MPa (absolute). Approximately a doubling of the gap length was necessary in case of a 0.5 kW heating in order to achieve the same 16% breakdown voltage or the same withstand voltage as in the case with no heating.

  9. A model of freezing foods with liquid nitrogen using special functions (United States)

    Rodríguez Vega, Martín.


    A food freezing model is analyzed analytically. The model is based on the heat diffusion equation in the case of cylindrical shaped food frozen by liquid nitrogen; and assuming that the thermal conductivity of the cylindrical food is radially modulated. The model is solved using the Laplace transform method, the Bromwich theorem, and the residue theorem. The temperature profile in the cylindrical food is presented as an infinite series of special functions. All the required computations are performed with computer algebra software, specifically Maple. Using the numeric values of the thermal and geometric parameters for the cylindrical food, as well as the thermal parameters of the liquid nitrogen freezing system, the temporal evolution of the temperature in different regions in the interior of the cylindrical food is presented both analytically and graphically. The duration of the liquid nitrogen freezing process to achieve the specified effect on the cylindrical food is computed. The analytical results are expected to be of importance in food engineering and cooking engineering. As a future research line, the formulation and solution of freezing models with thermal memory is proposed.

  10. Mathematical Model-Based Temperature Preparation of Liquid-Propellant Components Cooled by Liquid Nitrogen in the Heat Exchanger with a Coolant

    Directory of Open Access Journals (Sweden)

    S. K. Pavlov


    Full Text Available Before fuelling the tanks of missiles, boosters, and spacecraft with liquid-propellant components (LPC their temperature preparation is needed. The missile-system ground equipment performs this operation during prelaunch processing of space-purpose missiles (SPM. Usually, the fuel cooling is necessary to increase its density and provide heat compensation during prelaunch operation of SPM. The fuel temperature control systems (FTCS using different principles of operation and types of coolants are applied for fuel cooling.To determine parameters of LPC cooling process through the fuel heat exchange in the heat exchanger with coolant, which is cooled by liquid nitrogen upon contact heat exchange in the coolant reservoir, a mathematical model of this process and a design technique are necessary. Both allow us to determine design parameters of the cooling system and the required liquid nitrogen reserve to cool LPC to the appropriate temperature.The article presents an overview of foreign and domestic publications on cooling processes research and implementation using cryogenic products such as liquid nitrogen. The article draws a conclusion that it is necessary to determine the parameters of LPC cooling process through the fuel heat exchange in the heat exchanger with coolant, which is liquid nitrogen-cooled upon contact heat exchange in the coolant reservoir allowing to define rational propellant cooling conditions to the specified temperature.The mathematical model describes the set task on the assumption that a heat exchange between the LPC and the coolant in the heat exchanger and with the environment through the walls of tanks and pipelines of circulation loops is quasi-stationary.The obtained curves allow us to calculate temperature changes of LPC and coolant, cooling time and liquid nitrogen consumption, depending on the process parameters such as a flow rate of liquid nitrogen, initial coolant temperature, pump characteristics, thermal

  11. Cryopreservation of murine embryos, human spermatozoa and embryonic stem cells using a liquid nitrogen-free, controlled rate freezer. (United States)

    Morris, G J; Acton, E; Faszer, K; Franklin, A; Yin, H; Bodine, R; Pareja, J; Zaninovic, N; Gosden, R


    A Stirling Cycle Cryocooler has been developed as an alternative to conventional liquid nitrogen controlled rate freezers. Unlike liquid nitrogen systems, the Stirling Cycle freezer does not pose a contamination risk, can be used in sterile conditions and has no need for a constant supply of cryogen. Three types of samples from two species (murine embryos, human spermatozoa and embryonic stem cells), each requiring different cooling protocols, were cryopreserved in the Stirling Cycle freezer. For comparison, cells were also frozen in a conventional liquid nitrogen controlled rate freezer. Upon thawing, the rates of survival of viable cells were generally greater than 50% for mouse embryos and human embryonic stem cells, based on morphology (mouse embryos) and staining and colony formation (human embryonic stem cells). Survival rates of human spermatozoa frozen in the Stirling Cycle freezer, based on motility and dead cell staining, were similar to those of samples frozen in a conventional controlled rate freezer using liquid nitrogen.


    Energy Technology Data Exchange (ETDEWEB)

    Richard Schultz


    Advanced light water reactor systems are designed to use passive emergency core cooling systems with horizontal pipes that provide highly subcooled water from water storage tanks or passive heat exchangers to the reactor vessel core under accident conditions. Because passive systems are driven by density gradients, the horizontal pipes often do not flow full and thus have a free surface that is exposed to saturated steam and stratified flow is present.

  13. Flow Boiling Heat Transfer to Lithium Bromide Aqueous Solution in Subcooled Region (United States)

    Kaji, Masao; Furukawa, Masahiro; Nishizumi, Takeharu; Ozaki, Shinji; Sekoguchi, Kotohiko

    A theoretical prediction model of the boiling heat transfer coefficient in the subcooled region for water and lithium bromide aqueous solution flowing in a rectangular channel is proposed. In the present heat transfer model, a heat flux is assumed to consist of both the forced convective and the boiling effect components. The forced convective component is evaluated from the empirical correlation of convective heat transfer coefficient for single-phase flow considering the effect of increase of liquid velocity due to net vapor generation. Empirical correlations for determining the heat flux due to the boiling effect and the quality at the onset point of net vapor generation are obtained from the data presented in the first report1). Agreement between the present theoretical prediction and the experimental data is satisfactorily good both for water and lithium bromide aqueous solution.

  14. A verification and validation of the new implementation of subcooled flow boiling in a CFD code

    Energy Technology Data Exchange (ETDEWEB)

    Braz Filho, Francisco A.; Ribeiro, Guilherme B.; Caldeira, Alexandre D., E-mail:, E-mail:, E-mail: [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil). Divisao de Energia Nuclear


    Subcooled flow boiling in a heated channel occurs when the liquid bulk temperature is lower than the saturation temperature and the wall temperature is higher. FLUENT computational fluid dynamics code uses Eulerian Multiphase Model to analyze this phenomenon. In FLUENT previous versions, the heat transfer correlations and the source terms of the conservation equations were added to the model using User Defined Functions (UDFs). Currently, these models are among the options of the FLUENT without the need to use UDFs. The comparison of the FLUENT calculations with experimental data for the void fraction presented a wide range of variation in the results, with values from satisfactory to poor results. There was the same problem in the previous versions. The fit factors of the FLUENT that control condensation and boiling in the system can be used to improve the results. This study showed a strong need for verification and validation of these calculations, along with a sensitivity analysis of the main parameters. (author)

  15. Position reconstruction of bubble formation in liquid nitrogen using piezoelectric sensors (United States)

    Lenardo, B.; Li, Y.; Manalaysay, A.; Morad, J.; Payne, C.; Stephenson, S.; Szydagis, M.; Tripathi, M.


    Cryogenic liquids, particularly liquid xenon and argon, are of interest as detector media for experiments in nuclear and particle physics. Here we present a new detector diagnostic technique using piezoelectric sensors to detect bubbling of the liquid. Bubbling can indicate locations of excess heat dissipation e.g., in immersed electronics. They can also interfere with normal event evolution by scattering of light or by interrupting the drift of ionization charge. In our test apparatus, four sensors are placed in the vacuum space of a double-walled dewar of liquid nitrogen and used to detect and locate a source of bubbling inside the liquid volume. Utilizing the differences in transmitted frequencies through the different media present in the experiment, we find that sound traveling in a direct path from the source to the sensor can be isolated with appropriate filtering. The location of the source is then reconstructed using the time difference of arrivals (TDOA) information. The reconstruction algorithm is shown to have a 95.8% reproducibility rate and reconstructed positions are self-consistent to an average ±0.5 cm around the mean in x, y, and z. Systematic effects are observed to cause errors in reconstruction when bubbles occur very close to the surfaces of the liquid volume.

  16. Permeability evolution model and numerical analysis of coupled coal deformation, failure and liquid nitrogen cooling

    Directory of Open Access Journals (Sweden)

    Chunhui ZHANG

    Full Text Available How to quantitatively evaluate the permeability change of coalbed subjected to liquid nitrogen cooling is a key issue of enhanced-permeability technology of coalbed. To analyze the evolution process of permeability of coupled coal deformation, failure and liquid introgen cooling, the coal is supposed as elastic, brittle and plastic material. Its deformation process includes elastic deformation stage, brittle strength degradation stage and residual plastic flow stage. Combined with strength degradation index, dilatancy index of the element and Mohr-Column strength criterion, the element scale constitutive model with the effects of confining pressure on peak-post mechanical behaviors is built. Based on the deformation process of coal rock, there exist two stages of permeability evolution of the element including decrease of permeability due to elastic contraction and increase due to coal rock element's failure. The relationships between the permeability and elastic deformation, shear failure and tension failure for coal are studied. The permeability will be influenced by the change of pore space due to elastic contraction or tension of element. Conjugate shear zones appear during the shear failure of the element, in which the flow follows so-called cubic law between smooth parallel plates. The calculation formulas of the permeability and the aperture of the fractures are given out based on the volumetric strain. When tension failure criterion is satisfied with the rock element fails and two orthogonal fractures appear. The calculation formulas of the permeability and the width of the fractures are given out based on the volumetric strain. Further, combined with the thermal conduction theory the permeability evolution model of coupled coal deformation, failure and liquid nitrogen cooling is presented. Then Fish function method in FLAC is employed to perform the model. The permeability's evolution process for coal bed cryogenically stimulated

  17. A reliable procedure for decontamination before thawing of human specimens cryostored in liquid nitrogen: three washes with sterile liquid nitrogen (SLN2). (United States)

    Parmegiani, Lodovico; Accorsi, Antonio; Bernardi, Silvia; Arnone, Alessandra; Cognigni, Graciela Estela; Filicori, Marco


    To report a washing procedure, to be performed as frozen specimens are taken out of cryobanks, to minimize the risk of hypothetical culture contamination during thawing. Basic research. Private assisted reproduction center. Two batches of liquid nitrogen (LN(2)) were experimentally contaminated, one with bacteria (Pseudomonas aeruginosa, Escherichia coli, Stenotrophomonas maltophilia) and the other with fungi (Aspergillus niger). Two hundred thirty-two of the most common human gamete/embryo vitrification carriers (Cryotop, Cryoleaf, Cryopette) were immersed in the contaminated LN(2) (117 in the bacteria and 25 in the fungi-contaminated LN(2)). The carriers were tested microbiologically, one group without washing (control) and the other after three subsequent washings in certified ultraviolet sterile liquid nitrogen (SLN(2)). The carriers were randomly allocated to the "three-wash procedure" (three-wash group, 142 carriers) or "no-wash" (control group, 90 carriers) using a specific software tool. Assessment of microorganism growth. In the no-wash control group, 78.6% of the carriers were contaminated by the bacteria and 100% by the fungi. No carriers were found to be contaminated, either by bacteria or fungi, after the three-wash procedure. The three-wash procedure with SLN(2) produced an efficient decontamination of carriers in extreme experimental conditions. For this reason, this procedure could be routinely performed in IVF laboratories for safe thawing of human specimens that are cryostored in nonhermetical cryocontainers, particularly in the case of open or single-straw closed vitrification systems. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  18. Vapour-liquid equilibrium of nitrogen-oxygen mixtures and air at high pressure (United States)

    Rainwater, J. C.; Jacobsen, R. T.


    The vapor-liquid equilibrium surface of the binary mixture nitrogen-oxygen is correlated over an extended critical region with the Leung-Griffiths model as modified by Rainwater and Moldover (1983). No single comprehensive experimental measurement of the coexistence surface is available. However, several different experiments along isopleths, isotherms, and isobars collectively provide enough data to make possible the development of a reasonable correlation. The model is optimized to modern data and is shown to be consistent with pioneering measurements done before 1930, to within experimental and temperature-scale uncertainties. It is shown that air in the critical region can be accurately modeled as a nitrogen-oxygen binary mixture by including the small argon component with oxygen. Ancillary equations for the saturation properties of air as functions of temperature are also constructed.

  19. Feasibility of refreezing human spermatozoa through the technique of liquid nitrogen vapor

    Directory of Open Access Journals (Sweden)

    Sidney Verza Jr


    Full Text Available OBJECTIVE: To assess the feasibility of refreezing human semen using the technique of liquid nitrogen vapor with static phases. MATERIALS AND METHODS: Twenty samples from 16 subjects who required disposal of their cryopreserved semen were thawed, corresponding to 6 cancer patients and 10 participants in the assisted reproduction (AR program. Samples were refrozen using the technique of liquid nitrogen vapor with static phases, identical to the one used for the initial freezing, and thawed again after 72 hours. We assessed the concentration of motile spermatozoa, total and progressive percent motility and spermatic vitality, according to criteria of the World Health Organization (WHO, as well as spermatic morphology according to the strict Kruger criterion, after the first and after the second thawing. RESULTS: We observed a significant decrease in all the parameters evaluated between the first and the second thawing. Median values for the concentration of motile spermatozoa decreased from 2.0x10(6/mL to 0.1x10(6/mL (p < 0.01; total percent motility from 42% to 22.5% (p < 0.01; progressive percent motility from 34% to 9.5% (p < 0.01; vitality from 45% to 20% (p < 0.01; and morphology from 5% to 5% (p = 0.03. There was no significant difference in the spermatic parameters between the cancer and assisted reproduction groups, both after the first and after the second thawing. We observed that in 100% of cases there was retrieval of motile spermatozoa after the second thawing. CONCLUSIONS: Refreezing of human semen by the technique of liquid nitrogen vapor allows the retrieval of viable spermatozoa after thawing.

  20. Reactive Uptake of Ammonia and Formation of Organic Nitrogen Species for Non-Liquid/Liquid Secondary Organic Material (United States)

    Martin, S. T.; Li, Y.; Liu, P.


    Formation of ammonium and organic nitrogen (ON) species was studied for secondary organic material (SOM) of variable viscosity, ranging from non-liquid to liquid physical states. The SOM was produced as particles of 50 to 150 nm in diameter in aerosol form from six precursors, including three terpenoid and three aromatic species. The viscosity of the hygroscopic SOM was adjusted by exposure to relative humidity (RH) from 90% RH in steps of 10% at 293 ± 2 K. The aerosol was subsequently exposed to 5 ppm NH3 for mean reaction times of 30, 370, or 5230 s. Ammonium and ON were characterized by high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS). The ammonium-to-organic ratio of mass concentrations (MNH4/MOrg) in the particles increased monotonically from kinetics from a system limited by diffusivity within the SOM for low RH to one limited by other factors, such as saturated uptake, at higher RH. Formation of ON was observed for aromatic-derived SOMs, but not significant for terpenoid-derived SOMs. For aromatic-derived SOMs, the ON-to-organic ratio of mass concentrations (MON/MOrg) was negligible for RH 60%. The threshold RH for the switchover from kinetically controlled regime to a non-kinetically-controlled one was thus different between formation of ammonium and ON. This difference suggests that water may play a role in the slow reactions of ON formation as a reactant or a catalyst, in addition to affecting the reactant diffusion as in the fast reaction of ammonium formation. The implication is that formation of ammonium salts and organic nitrogen species by certain SOMs should be treated separately in chemical transport models to reflect the different roles of water that may affect the phase state of the SOMs or may act as a reactant or a catalyst.

  1. Determination of heat transfer coefficients in plastic French straws plunged in liquid nitrogen. (United States)

    Santos, M Victoria; Sansinena, M; Chirife, J; Zaritzky, N


    The knowledge of the thermodynamic process during the cooling of reproductive biological systems is important to assess and optimize the cryopreservation procedures. The time-temperature curve of a sample immersed in liquid nitrogen enables the calculation of cooling rates and helps to determine whether it is vitrified or undergoes phase change transition. When dealing with cryogenic liquids, the temperature difference between the solid and the sample is high enough to cause boiling of the liquid, and the sample can undergo different regimes such as film and/or nucleate pool boiling. In the present work, the surface heat transfer coefficients (h) for plastic French straws plunged in liquid nitrogen were determined using the measurement of time-temperature curves. When straws filled with ice were used the cooling curve showed an abrupt slope change which was attributed to the transition of film into nucleate pool boiling regime. The h value that fitted each stage of the cooling process was calculated using a numerical finite element program that solves the heat transfer partial differential equation under transient conditions. In the cooling process corresponding to film boiling regime, the h that best fitted experimental results was h=148.12±5.4 W/m(2) K and for nucleate-boiling h=1355±51 W/m(2) K. These values were further validated by predicting the time-temperature curve for French straws filled with a biological fluid system (bovine semen-extender) which undergoes freezing. Good agreement was obtained between the experimental and predicted temperature profiles, further confirming the accuracy of the h values previously determined for the ice-filled straw. These coefficients were corroborated using literature correlations. The determination of the boiling regimes that govern the cooling process when plunging straws in liquid nitrogen constitutes an important issue when trying to optimize cryopreservation procedures. Furthermore, this information can lead to

  2. Experimental investigation of passive thermodynamic vent system (TVS) with liquid nitrogen (United States)

    Bae, Junhyuk; Yoo, Junghyun; Jin, Lingxue; Jeong, Sangkwon


    Thermodynamic vent system (TVS) is an attractive technology to maintain an allowable pressure level of a cryogenic propellant storage in a spacecraft under micro-gravity condition. There are two types of TVS; active or passive. In this paper, the passive TVS which does not utilize a cryogenic liquid circulation pump is experimentally investigated with liquid nitrogen and numerically analyzed by thermodynamic and heat transfer model. A cylindrical copper tank, which is 198 mm in inner diameter and 216 mm in height, is utilized to suppress a thermal-stratification effect of inside cryogenic fluid. A coil heat exchanger, which is 3 m in length and 6.35 mm in outer diameter, and a fixed size orifice of which diameter is 0.4 mm are fabricated to remove heat from the stored fluid to the vented flow. Each vent process is initiated at 140 kPa and ended at 120 kPa with liquid nitrogen fill levels which are 30%, 50% and 70%, respectively. In the numerical model, the fluid in the tank is assumed to be homogeneous saturated liquid-vapor. Mass and energy balance equations with heat transfer conditions suggested in this research are considered to calculate the transient pressure variation in the tank and the amount of heat transfer across the heat exchanger. We achieve the average heat rejection rate of more than 9 W by TVS and conclude that the passive TVS operates satisfactorily. In addition, the prediction model is verified by experimental results. Although the model has limitation in providing accurate results, it can surely predict the tendency of pressure and temperature changes in the tank. Furthermore, the model can suggest how we can improve the heat exchanger design to enhance an overall efficiency of passive TVS. Moreover, the performance of passive TVS is compared with other cryogenic vent systems (direct vent system and active TVS) by suggested performance indicator.

  3. Observing Nitrogen Bubbles in Liquid Zinc in a Vertical Hele-Shaw Cell (United States)

    Klaasen, Bart; Verhaeghe, Frederik; Blanpain, Bart; Fransaer, Jan


    Observations of gas bubbles in liquid metal are strongly hindered by the opacity of metals. To circumvent this limitation, the authors recently proposed to study such systems under quasi-2D flow conditions in a Hele-Shaw cell. The current paper presents a successful application of this approach for nitrogen bubbles in liquid zinc at 973 K (700 °C) in a fused quartz cell with a thickness of 1.5 mm. At low oxygen levels, the cell walls are not wetted by the liquid zinc, and bubbles can be observed directly through the transparent cell walls. Furthermore, using a moving high-speed camera that travels upwards with the bubbles, their properties are quantified in detail along the entire trajectory. In the range of equivalent diameters between 5.9 and 9.0 mm, this reveals a single periodic flow regime in which bubbles follow a sinusoidal path with a characteristic frequency of 3.31 Hz. In addition, systematic intermediate accelerations are observed of which the origin remains unexplained. Considering the unprecedented resolution of such observations for bubbles in liquid metals, especially at high temperatures, it is expected that this approach will contribute to a better understanding of the mechanisms that govern gas injection in pyrometallurgy.

  4. Phase transition and chemical decomposition of liquid carbon dioxide and nitrogen mixture under extreme conditions (United States)

    Xiao-Xu, Jiang; Guan-Yu, Chen; Yu-Tong, Li; Xin-Lu, Cheng; Cui-Ming, Tang


    Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen (CO2-N2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic (QMD) simulations based on density functional theory including dispersion corrections (DFT-D). We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm3 to 3.40 g/cm3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO2-N2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions (PCFs) and the distribution of various molecular components. The insulator-metal transition is demonstrated by means of the electronic density of states (DOS). Project supported by the National Natural Science Foundation of China (Grant Nos. 11374217, 11135012, and 11375262) and the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant No. 11176020).

  5. Time dependent heat transport in subcooled superfluid helium (United States)

    Seyfert, P.; Lafferranderie, J.; Claudet, G.

    The authors present an extensive study on the behaviour of time dependent heat transport in subcooled He II under conditions which are closely related to the cooling problem of superconducting magnets. Experimental results on the delay for onset of burnout and on the transient recovery from burnout are discussed. A theoretical model is derived from the assumption that heat diffusion characterized by the Gorter-Mellink equation is the dominant mode of heat transport and that thermal waves play no direct role in this connection. The comparison of experimental and calculated results shows a very satisfactory agreement which fully validates the model.

  6. Soft X-ray and cathodoluminescence measurement, optimisation and analysis at liquid nitrogen temperatures (United States)

    MacRae, C. M.; Wilson, N. C.; Torpy, A.; Delle Piane, C.


    Advances in field emission gun electron microprobes have led to significant gains in the beam power density and when analysis at high resolution is required then low voltages are often selected. The resulting beam power can lead to damage and this can be minimised by cooling the sample down to cryogenic temperatures allowing sub-micrometre imaging using a variety of spectrometers. Recent advances in soft X-ray emission spectrometers (SXES) offer a spectral tool to measure both chemistry and bonding and when combined with spectral cathodoluminescence the complementary techniques enable new knowledge to be gained from both mineral and materials. Magnesium and aluminium metals have been examined at both room and liquid nitrogen temperatures by SXES and the L-emission Fermi-edge has been observed to sharpen at the lower temperatures directly confirming thermal broadening of the X-ray spectra. Gains in emission intensity and resolution have been observed in cathodoluminescence for liquid nitrogen cooled quartz grains compared to ambient temperature quartz. This has enabled subtle growth features at quartz to quartz-cement boundaries to be imaged for the first time.

  7. Complete Numerical Simulation of Subcooled Flow Boiling in the Presence of Thermal and Chemical Interactions

    Energy Technology Data Exchange (ETDEWEB)

    V.K. Dhir


    At present, guidelines for fuel cycle designs to prevent axial offset anomalies (AOA) in pressurized water reactor (PWR) cores are based on empirical data from several operating reactors. Although the guidelines provide an ad-hoc solution to the problem, a unified approach based on simultaneous modeling of thermal-hydraulics, chemical, and nuclear interactions with vapor generation at the fuel cladding surface does not exist. As a result, the fuel designs are overly constrained with a resulting economic penalty. The objective of present project is to develop a numerical simulation model supported by laboratory experiments that can be used for fuel cycle design with respect to thermal duty of the fuel to avoid economic penalty, as well as, AOA. At first, two-dimensional numerical simulation of the growth and departure of a bubble in pool boiling with chemical interaction is considered. A finite difference scheme is used to solve the equations governing conservation of mass, momentum, energy, and species concentration. The Level Set method is used to capture the evolving liquid-vapor interface. A dilute aqueous boron solution is considered in the simulation. From numerical simulations, the dynamic change in concentration distribution of boron during the bubble growth shows that the precipitation of boron can occur near the advancing and receding liquid-vapor interface when the ambient boron concentration level is 3,000 ppm by weight. Secondly, a complete three-dimensional numerical simulation of inception, growth and departure of a single bubble subjected to forced flow parallel to the heater surface was developed. Experiments on a flat plate heater with water and with boron dissolved in the water were carried out. The heater was made out of well-polished silicon wafer. Numbers of nucleation sites and their locations were well controlled. Bubble dynamics in great details on an isolated nucleation site were obtained while varying the wall superheat, liquid subcooling

  8. Thermodynamic analysis of chromium solubility data in liquid lithium containing nitrogen: Comparison between experimental data and computer simulation

    Energy Technology Data Exchange (ETDEWEB)

    Krasin, Valery P., E-mail:; Soyustova, Svetlana I.


    The mathematical formalism for description of solute interactions in dilute solution of chromium and nitrogen in liquid lithium have been applied for calculating of the temperature dependence of the solubility of chromium in liquid lithium with the various nitrogen contents. It is shown that the derived equations are useful to provide understanding of a relationship between thermodynamic properties and local ordering in the Li–Cr–N melt. Comparison between theory and data reported in the literature for solubility of chromium in nitrogen-contaminated liquid lithium, was allowed to explain the reasons of the deviation of the experimental semi-logarithmic plot of chromium content in liquid lithium as a function of the reciprocal temperature from a straight line. - Highlights: • The activity coefficient of chromium in ternary melt can be obtained by means of integrating the Gibbs–Duhem equation. • In lithium with the high nitrogen content, the dependence of a logarithm of chromium solubility as a function of the reciprocal temperature has essentially nonlinear character. • At temperatures below a certain threshold, the process of dissolution of chromium in lithium will be controlled by the equilibrium concentration of nitrogen required for the formation of ternary nitride Li{sub 9}CrN{sub 5}at a given temperature.

  9. A Measurement of the Absorption of Liquid Argon Scintillation Light by Dissolved Nitrogen at the Part-Per-Million Level

    Energy Technology Data Exchange (ETDEWEB)

    Jones, B. J.P. [MIT, LNS; Chiu, C. S. [MIT, LNS; Conrad, J. M. [MIT, LNS; Ignarra, C. M. [MIT, LNS; Katori, T. [MIT, LNS; Toups, M. [MIT, LNS


    Here we report on a measurement of the absorption length of scintillation light in liquid argon due to dissolved nitrogen at the part-per-million (ppm)level. We inject controlled quantities of nitrogen into a high purity volume of liquid argon and monitor the light yield from an alpha source.The source is placed at different distances from a cryogenic photomultiplier tube assembly. By comparing the light yield from each position we extract the absorption cross section of nitrogen. We find that nitrogen absorbs argon scintillation light with strength of (1.51±0.15) × 10$-$4 cm$-$1ppm$-$1, correspondingto an absorption cross section of (4.99±0.51) × 10$-$21 cm2 molecule$-$1.We obtain the relationship between absorption length and nitrogenconcentration over the 0 to 50 ppm range and discuss the implicationsfor the design and data analysis of future large liquid argon time projection chamber (LArTPC)detectors. Our results indicate that for a current-generation LArTPC, wherea concentration of 2 parts per million of nitrogen is expected, the attenuationlength due to nitrogen will be 30±3 meters.

  10. Water evaporation in vertical tubes: an analytical approach for the subcooled flow boiling region and development of a method for evaluation and sizing evaporators = Evaporación de agua en tubos verticales: análisis de la región de ebullición subenfriada y desarrollo de un método de evaluación y Dimensionado de evaporadores


    Zambrana González, José


    The present thesis analyses in detail the process of water evaporation for convective upward flows in vertical tubes, used in industrial applications. Both, the heat transfer process and the pressure drop mechanism, are considered. However, special attention has been put on the heat transfer process in the transition from pure liquid to two-phase flow, known as subcooled flow boiling region. The empirical correlations for the heat transfer coefficient on the water side for subcooled flow boil...

  11. Switching Properties of Liquid Nitrogen Cooled IGBTs and 24 kA Demonstration of Current Multiplier by Inductive Storage (United States)

    Yamada, S.; Nakayama, H.; Aso, Y.


    We had been developing a current multiplier by inductive storage (CMIS). The CMIS consists of 24 storage copper coils, which soaked into the liquid nitrogen, demonstrates a 24 kA of output current and the continuous current pulses of 3 pulses per second. Switching performance of the IGBTs and diode were tested in the liquid nitrogen bath. These experimental data were used to design the mega-ampere class CMIS. The system consists of the superconductive magnet section with a temperature of 20 K and the IGBT control switch section with a temperature of 77 K.

  12. Mathematical prediction of freezing times of bovine semen in straws placed in static vapor over liquid nitrogen. (United States)

    Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J


    A widespread practice in cryopreservation is to freeze spermatozoa by suspending the straws in stagnant nitrogen vapor over liquid nitrogen (N(2)V/LN(2)) for variable periods of time before plunging into liquid nitrogen (-196°C) for indefinite storage. A mathematical heat transfer model was developed to predict freezing times (phase change was considered) required for bull semen and extender packaged in 0.5ml plastic straws and suspended in static liquid nitrogen vapor. Thermophysical properties (i.e. thermal conductivity, specific heat, density, initial freezing temperature) of bovine semen and extender as a function of temperature were determined considering the water change of phase. The non-stationary heat transfer partial differential equations with variable properties (nonlinear mathematical problem) were numerically solved considering in series thermal resistances (semen suspension-straw) and the temperature profiles were obtained for both semen suspension and plastic straw. It was observed both the external heat transfer coefficient in stagnant nitrogen vapor and its temperature (controlled by the distance from the surface of liquid nitrogen to the straw) affected freezing times. The accuracy of the model to estimate freezing times of the straws was further confirmed by comparing with experimental literature data. Results of this study will be useful to select "safe" holding times of bull semen in plastic straws placed N(2)V/LN(2) to ensure that complete freezing of the sample has occurred in the nitrogen vapor and avoid cryodamage when plunging in LN(2). Freezing times predicted by the numerical model can be applied to optimize freezing protocols of bull semen in straws. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Simple fundamental equation of state for liquid, gas, and fluid of argon, nitrogen, and carbon dioxide (United States)

    Kaplun, A. B.; Meshalkin, A. B.


    A new fundamental low-parametric equation of state in the form of reduced Helmholtz function for describing thermodynamic properties of normal substances was obtained using the methods and approaches developed earlier by the authors. It allows us to describe the thermal properties of gas, liquid, and fluid in the range from the density in ideal-gas state to the density at a triple point (except the critical region) with sufficiently high accuracy close to the accuracy of experiment. The caloric properties and sound velocity of argon, nitrogen, and carbon dioxide are calculated without involving any caloric data, except the ideal gas enthalpy. The obtained values of isochoric heat capacity, sound velocity, and other thermodynamic properties are in good agreement with experimental (reliable tabular) data.

  14. Demonstration of liquid nitrogen wicking using a multi-layer metallic wire cloth laminate (United States)

    Zhang, Tao; deBock, Peter; Stautner, Ernst Wolfgang; Deng, Tao; Immer, Chris


    Cryogenic heat transport devices are the most basic and critical component for the thermal integration between the cryogenic component and its cooling source. In space environments, containment of heat transfer fluid inside a capillary structure is critical due to the absence of gravity. Cryogenic heat pipes using the capillary force for circulation may provide a solution for heat transfer in space applications due to its independence of gravity and transport distance. To achieve a high effective capillary performance, several options of wicking structures have been investigated. An efficient wicking flow of liquid nitrogen is demonstrated with a sintered, multi-layer, porous lamination of metal wire (pore size as low as 5 μm) in an open cryogenic chamber. The test data are presented in this paper. This technology has potential for use in development of improved cryogenic heat transfer devices and containment of cryogenic propellants under micro-gravity environment.

  15. The Characteristics of Frequency Spectrum of Radiated Electromagnetic Waves with AC Discharge Progress in Liquid Nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Park, K.S.; Yoon, D.H.; Lee, S.H.; Kim, K.C.; Lee, K.S. [Yeungnam University, Gyeongsan (Korea); Lee, H.D. [LG Industrial Systems Co., Ltd., Cheongju (Korea); Kim, C.M. [Kyungwoon University, Kumi (Korea); Choi, B.J. [Sorabol College, Gyeongju (Korea)


    In this paper, a relationship between AC discharge progress and the radiated electromagnetic waves was investigated by measuring electromagnetic waves using a biconical antenna and a spectrum analyzer. The frequency spectrum of the radiated electromagnetic waves were measured at the atmospheric pressure in liquid nitrogen(LN{sub 2}) during partial discharges progressed by AC high voltage in nonuniform electric field. From the results of this study, a new method was introduced for measurement and analysis of the radiated electromagnetic waves with discharge progress in LN{sub 2}. Besides, according to the consideration of the mutual relation between frequency spectrum of the radiated electromagnetic waves and discharge progress, it was confirmed that detecting partial discharge and estimating discharge progress could be possible. It is considered that these results obtained from this investigation may be used as fundamental data for diagnosis and prediction of electric insulations about superconducting and cryogenic power equipments. (author). 14 refs., 7 figs.

  16. Development and fundamental characteristics of a YBCO superconducting induction/synchronous motor operated in liquid nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, K [Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura 1, Nishikyo-Ku, Kyoto 615-8510 (Japan); Nakamura, T [Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura 1, Nishikyo-Ku, Kyoto 615-8510 (Japan); Nishimura, T [Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura 1, Nishikyo-Ku, Kyoto 615-8510 (Japan); Ogama, Y [Department of Electrical Engineering, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku Katsura 1, Nishikyo-Ku, Kyoto 615-8510 (Japan); Kashima, N [Electric Power Research and Development Center, Research and Development Division, Chubu Electric Power Co., Incorporated, 20-1, Kita-Sekiyama, Ootaka-Cho Aza, Midori-Ku, Nagoya 459-8522 (Japan); Nagaya, S [Electric Power Research and Development Center, Research and Development Division, Chubu Electric Power Co., Incorporated, 20-1, Kita-Sekiyama, Ootaka-Cho Aza, Midori-Ku, Nagoya 459-8522 (Japan); Suzuki, K [Superconductivity Research Laboratory, International Superconductivity Technology Center, 10-13, Shinonome 1-chome, Koto-Ku, Tokyo 135-0062 (Japan); Izumi, T [Superconductivity Research Laboratory, International Superconductivity Technology Center, 10-13, Shinonome 1-chome, Koto-Ku, Tokyo 135-0062 (Japan); Shiohara, Y [Superconductivity Research Laboratory, International Superconductivity Technology Center, 10-13, Shinonome 1-chome, Koto-Ku, Tokyo 135-0062 (Japan)


    A high T{sub c} superconducting induction/synchronous motor (HTS-ISM) is designed, fabricated and tested with the use of YBCO coated conductors for rotor bars. The structure of this motor is the same with that of the squirrel-cage induction motor. The YBCO coated conductor, 10 mm in width, is produced by means of the MOCVD process, and then such tape is divided into four pieces by using a laser cutting machine. Four cut tapes are bundled for one rotor bar, and commercialized Bi-2223/Ag tapes are utilized for end rings. The fabricated HTS rotor is installed in a conventional stator, and then various tests are carried out in liquid nitrogen. It is successfully observed that the fabricated YBCO HTS-ISM has a synchronous torque. The motor also has an almost constant torque curve because of the steep take-off of the electric field versus current density property. Detailed test results are reported and discussed.


    Directory of Open Access Journals (Sweden)

    Lara-Herrera Isabel


    Full Text Available Viability of 6 mushroom strains of the Pleurotus genus (2 from P. djamor var. djamor, 1 from P. ostreatus var. ostreatus, 2 from P. ostreatus var. columbinus and 1 from P. pulmonarius after liquid nitrogen cryopreservation (-196º was evaluated. The contact time for the mycelia of these strains with the cryoprotectant (glycerol was studied 1, 2 and 3 hours before freezing. We also tested the effect of different times (5, 10 and 15 minutes and temperatures (30, 45 and 60ºC of the thawing system for mycelial recovery. The results showed a marked tendency toward faster mycelial recovery when samples were thawed at 30ºC, while at 60ºC no recovery was observed. A change in thawing and contact times with the cryoprotectant did not affect the results significantly, as the thawing temperature and strain employed affected.

  18. Process configuration of Liquid-nitrogen Energy Storage System (LESS) for maximum turnaround efficiency (United States)

    Dutta, Rohan; Ghosh, Parthasarathi; Chowdhury, Kanchan


    Diverse power generation sector requires energy storage due to penetration of variable renewable energy sources and use of CO2 capture plants with fossil fuel based power plants. Cryogenic energy storage being large-scale, decoupled system with capability of producing large power in the range of MWs is one of the options. The drawback of these systems is low turnaround efficiencies due to liquefaction processes being highly energy intensive. In this paper, the scopes of improving the turnaround efficiency of such a plant based on liquid Nitrogen were identified and some of them were addressed. A method using multiple stages of reheat and expansion was proposed for improved turnaround efficiency from 22% to 47% using four such stages in the cycle. The novelty here is the application of reheating in a cryogenic system and utilization of waste heat for that purpose. Based on the study, process conditions for a laboratory-scale setup were determined and presented here.

  19. Polymeric Bladder for Storing Liquid Oxygen (United States)

    Walker, David H.; Harvey, Andrew C.; Leary, William


    A proposed system for storing oxygen in liquid form and dispensing it in gaseous form is based on (1) initial subcooling of the liquid oxygen; (2) containing the liquid oxygen in a flexible vessel; (3) applying a gas spring to the flexible vessel to keep the oxygen compressed above the saturation pressure and, thus, in the liquid state; and (4) using heat leakage into the system for vaporizing the oxygen to be dispensed. In a typical prior system based on these principles, the flexible vessel is a metal bellows housed in a rigid tank, and the gas spring consists of pressurized helium in the tank volume surrounding the bellows. Unfortunately, the welds in the bellows corrugations are subject to fatigue, and, because bellows have large ullage, a correspondingly large fraction of the oxygen content cannot be expelled. In the proposed system, the flexible vessel would be a bladder made of a liquid- crystal polymer (LCP). (LCPs are strong and compatible with liquid oxygen.) In comparison with a metal bellows, a polymeric bladder would have less ullage and would weigh less. In experiments involving fatigue cycling at liquid-nitrogen temperatures, two LCPs were found to be suitable for this application.

  20. The effects of geometric, flow, and boiling parameters on bubble growth and behavior in subcooled flow boiling (United States)

    Samaroo, Randy

    Air bubble injection and subcooled flow boiling experiments have been performed to investigate the liquid flow field and bubble nucleation, growth, and departure, in part to contribute to the DOE Nuclear HUB project, Consortium for Advanced Simulation of Light Water Reactors (CASL). The main objective was to obtain quantitative data and compartmentalize the many different interconnected aspects of the boiling process -- from the channel geometry, to liquid and gas interactions, to underlying heat transfer mechanisms. The air bubble injection experiments were performed in annular and rectangular geometries and yielded data on bubble formation and departure from a small hole on the inner tube surface, subsequent motion and deformation of the detached bubbles, and interactions with laminar or turbulent water flow. Instantaneous and ensemble- average liquid velocity profiles have been obtained using a Particle Image Velocimetry technique and a high speed video camera. Reynolds numbers for these works ranged from 1,300 to 7,700. Boiling experiments have been performed with subcooled water at atmospheric pres- sure in the same annular channel geometry as the air injection experiments. A second flow loop with a slightly larger annular channel was constructed to perform further boiling experiments at elevated pressures up to 10 bar. High speed video and PIV measurements of turbulent velocity profiles in the presence of small vapor bubbles on the heated rod are presented. The liquid Reynolds number for this set of experiments ranged from 5,460 to 86,000. It was observed that as the vapor bubbles are very small compared to the injected air bubbles, further experiments were performed using a microscopic objective to obtain higher spatial resolution for velocity fields near the heated wall. Multiple correlations for the bubble liftoff diameter, liftoff time and bub- ble history number were evaluated against a number of experimental datasets from previous works, resulting in a

  1. Application of a Novel Liquid Nitrogen Control Technique for Heat Stress and Fire Prevention in Underground Mines. (United States)

    Shi, Bobo; Ma, Lingjun; Dong, Wei; Zhou, Fubao


    With the continually increasing mining depths, heat stress and spontaneous combustion hazards in high-temperature mines are becoming increasingly severe. Mining production risks from natural hazards and exposures to hot and humid environments can cause occupational diseases and other work-related injuries. Liquid nitrogen injection, an engineering control developed to reduce heat stress and spontaneous combustion hazards in mines, was successfully utilized for environmental cooling and combustion prevention in an underground mining site named "Y120205 Working Face" (Y120205 mine) of Yangchangwan colliery. Both localized humidities and temperatures within the Y120205 mine decreased significantly with liquid nitrogen injection. The maximum percentage drop in temperature and humidity of the Y120205 mine were 21.9% and 10.8%, respectively. The liquid nitrogen injection system has the advantages of economical price, process simplicity, energy savings and emission reduction. The optimized heat exchanger used in the liquid nitrogen injection process achieved superior air-cooling results, resulting in considerable economic benefits.

  2. Bubble and boundary layer behaviour in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Maurus, Reinhold; Sattelmayer, Thomas [Lehrstuhl fuer Thermodynamik, Technische Universitaet Muenchen, 85747 Garching (Germany)


    Subcooled flow boiling is a commonly applied technique for achieving efficient heat transfer. In the study, an experimental investigation in the nucleate boiling regime was performed for water circulating in a closed loop at atmospheric pressure. The horizontal orientated test-section consists of a rectangular channel with a one side heated copper strip and good optical access. Various optical observation techniques were applied to study the bubble behaviour and the characteristics of the fluid phase. The bubble behaviour was recorded by the high-speed cinematography and by a digital high resolution camera. Automated image processing and analysis algorithms developed by the authors were applied for a wide range of mass flow rates and heat fluxes in order to extract characteristic length and time scales of the bubbly layer during the boiling process. Using this methodology, the bubbles were automatically analysed and the bubble size, bubble lifetime, waiting time between two cycles were evaluated. Due to the huge number of observed bubbles a statistical analysis was performed and distribution functions were derived. Using a two-dimensional cross-correlation algorithm, the averaged axial phase boundary velocity profile could be extracted. In addition, the fluid phase velocity profile was characterised by means of the particle image velocimetry (PIV) for the single phase flow as well as under subcooled flow boiling conditions. The results indicate that the bubbles increase the flow resistance. The impact on the flow exceeds by far the bubbly region and it depends on the magnitude of the boiling activity. Finally, the ratio of the averaged phase boundary velocity and of the averaged fluid velocity was evaluated for the bubbly region. (authors)

  3. Retention of nitrogen and phosphorous from liquid swine and poultry manures using highly characterized peats. (United States)

    Rizzuti, Anthony M; Cohen, Arthur D; Hunt, Patrick G; Ellison, Aprel Q


    This paper reports on research designed to test the hypothesis that differences in peat composition will cause differences in amounts of N and P retained during contact with liquid swine manure (LSM) and liquid poultry manure (LPM). Peat types representing a wide range of properties were tested in order to establish which chemical and physical properties might be most indicative of their capacities to retain N and P from LSM and LPM. Eight-percent slurries (peat/LSM and peat/LPM) were measured for total nitrogen (TKN) and total phosphorous (TP) after 6, 24 and 96 hours. Tests were done to determine the TKN and TP contents of these peats, the LSM, and the LPM, both before and after they were mixed together. The N and P retention results revealed that most peats worked reasonably well at retaining N and P from either LSM or LPM. However, some peats were more effective than others. These peats also decreased the N and P levels in the liquid portion of the LSM. Peats with higher N retention capacities tended to have lower ash contents, but higher macroporosities and total cellulose contents. Peats with higher P retention capacities tended to have lower bulk densities, ash contents, total guaiacyl lignins contents, fulvic acids contents, but higher microporosities, macroporosities, H contents, and total cellulose contents. Peats with higher N and P retention capacities also had humic acid contents between 5-7%. The results of this study suggest that if these peats are used to reduce odors and N and P contamination, possible byproducts could be the production of odorless fertilizers.

  4. Bubble detachment and lift-off diameters at a vertical heated wall for subcooled boiling flow

    Energy Technology Data Exchange (ETDEWEB)

    Montout, Michael; Haynes, Pierre-Antoine; Peturaud, Pierre [EDF, R and D Division, Fluid Dynamics, Power Generation and Environnement Department, 6 quai Watier, 78401 Chatou Cedex (France); Colin, Catherine [Institut de Mecanique des Fluides de Toulouse, Allee du Professeur Camille Soula, 31400 Toulouse (France)


    Full text of publication follows: In the framework of the NEPTUNE project jointly carried on by EDF, CEA, AREVA NP and IRSN (Guelfi et al. (2007)), the development of the NEPTUNE-CFD code aims at (among others) improving the prediction of the Departure from Nucleate Boiling (DNB) in Pressurized Water Reactors (PWRs). In this prospect, the modeling of boiling flows up to the DNB is of prime importance, and this presentation is devoted to one major related phenomenon, the wall-to-flow heat transfer in subcooled boiling flow. Computational Fluid Dynamics (CFD) modeling of subcooled nucleate boiling has to provide the net vapor generation rate at the heated wall, as well as its related geometrical characteristic - either bubble diameter or interfacial area concentration (its velocity might also be useful). For this purpose, mechanistic models are used. Previous models (such as the widely used Kurul and Podowski model (1990)) are based on the bubble lift-off diameter, diameter from which the bubble leaves the wall to be swept along the bulk liquid flow. However, for a few years, new models (Basu et al. (2005) or Yeoh et al. (2008)) account for a finer phenomenology (bubble sliding along the heated wall) and require the knowledge of the bubble detachment diameter, diameter from which the bubble leaves its nucleation site to slide along the heated wall. Modeling these diameters is still an issue. On the one hand, several (semi-) empirical correlations are available in the open literature making it possible to provide the liftoff diameter (Uenal (1976), for instance), but they are still questionable; on the other hand, there is a great lack of information with respect to the evaluation of the detachment diameter. Therefore to progress on these concerns, an analytical work has been carried out. In a first step, a methodology providing detachment and lift-off diameters is proposed and applied. This approach is based on the resolution of a force balance model acting on a

  5. Prediction of subcooled flow boiling characteristics using two-fluid Eulerian CFD model

    Energy Technology Data Exchange (ETDEWEB)

    Braz Filho, Francisco A.; Ribeiro, Guilherme B., E-mail:; Caldeira, Alexandre D.


    Highlights: • CFD multiphase model is used to predict subcooled flow boiling characteristics. • Better agreement is achieved for higher saturation pressures. • Onset of nucleate boiling and saturated boiling are well predicted. • CFD multiphase model tends to underestimate the void fraction. • Factors were adjusted in order to improve the void fraction results. - Abstract: The present study concerns a detailed analysis of flow boiling phenomena under high pressure systems using a two-fluid Eulerian approach provided by a Computational Fluid Dynamics (CFD) solver. For this purpose, a vertical heated pipe made of stainless steel with an internal diameter of 15.4 mm was considered as the modeled domain. Two different uniform heat fluxes and three saturation pressures were applied to the channel wall, whereas water mass flux of 900 kg/m{sup 2} s was considered for all simulation cases. The model was validated against a set of experimental data and results have indicated a promising use of the CFD technique for estimation of the wall temperature, the liquid bulk temperature and the location of the departure of nucleate boiling. Changes in factors applied in the modeling of the interfacial heat transfer coefficient and bubble departure frequency were suggested, allowing a better prediction of the void fraction along the heated channel. The commercial CFD solver FLUENT 14.5 was used for the model implementation.

  6. Transition process leading to microbubble emission boiling on horizontal circular heated surface in subcooled pool (United States)

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


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

  7. Real Time, Non-intrusive Detection of Liquid Nitrogen in Liquid Oxygen (LOX) at High Pressure and High Flow Project (United States)

    National Aeronautics and Space Administration — Technical Abstract The Stennis Space Center (SSC) needs the sensors that are capable and can be operated in liquid oxygen (LOX) and or liquid hydrogen (LH2)...

  8. Real time, Non-intrusive Detection of Liquid Nitrogen in Liquid Oxygen (LOX) at High Pressure and High Flow Project (United States)

    National Aeronautics and Space Administration — SSC needs the sensors that are capable and can be operated in liquid oxygen (LOX) and or liquid hydrogen (LH2) cryogenic environment to improve SSC cryogenic...

  9. Assessment of external heat transfer coefficient during oocyte vitrification in liquid and slush nitrogen using numerical simulations to determine cooling rates. (United States)

    Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J


    In oocyte vitrification, plunging directly into liquid nitrogen favor film boiling and strong nitrogen vaporization. A survey of literature values of heat transfer coefficients (h) for film boiling of small metal objects with different geometries plunged in liquid nitrogen revealed values between 125 to 1000 W per per square m per K. These h values were used in a numerical simulation of cooling rates of two oocyte vitrification devices (open-pulled straw and Cryotop), plunged in liquid and slush nitrogen conditions. Heat conduction equation with convective boundary condition was considered a linear mathematical problem and was solved using the finite element method applying the variational formulation. COMSOL Multiphysics was used to simulate the cooling process of the systems. Predicted cooling rates for OPS and Cryotop when cooled at -196 degree C (liquid nitrogen) or -207 degree C (average for slush nitrogen) for heat transfer coefficients estimated to be representative of film boiling, indicated lowering the cooling temperature produces only a maximum 10 percent increase in cooling rates; confirming the main benefit of plunging in slush over liquid nitrogen does not arise from their temperature difference. Numerical simulations also demonstrated that a hypothetical four-fold increase in the cooling rate of vitrification devices when plunging in slush nitrogen would be explained by an increase in heat transfer coefficient. This improvement in heat transfer (i.e., high cooling rates) in slush nitrogen is attributed to less or null film boiling when a sample is placed in slush (mixture of liquid and solid nitrogen) because it first melts the solid nitrogen before causing the liquid to boil and form a film.

  10. Design and construction of a guarded hot plate apparatus operating down to liquid nitrogen temperature. (United States)

    Li, Manfeng; Zhang, Hua; Ju, Yonglin


    A double-sided guarded hot plate apparatus (GHP) is specifically designed, fabricated, and constructed for the measurement of thermal conductivities of insulation specimens operated down to liquid nitrogen temperature (-196 °C), at different controlled pressures from 0.005 Pa to 0.105 MPa. The specimens placed in this apparatus are 300 mm in diameter at various thicknesses ranging from 4 mm to 40 mm. The apparatus is different from traditional GHP in terms of structure, supporting and heating method. The details of the design and construction of the hot plate, the cold plates, the suspensions, the clampings, and the vacuum chamber of the system are presented. The measurement methods of the temperatures, the input power, the meter area, and the thickness of the specimens are given. The apparatus is calibrated with teflon plates as sample and the maximum deviation from the published data is about 6% for thermal conductivity. The uncertainties for the measurement are also discussed in this paper.

  11. Perturbation theory for the thermodynamic properties of liquid nitrogen using model potentials (United States)

    Watanabe, K.; Allnatt, A. R.; Meath, W. J.

    A statistical mechanical perturbation theory due to Fischer has been used to calculate thermodynamic properties of liquid nitrogen for model intermolecular potentials due to Cheung and Powles (CP), Raich and Gillis (RG), and Berns and van der Avoird (BV). Refinements in the numerical implementation of the Fischer theory are described. Results for the CP potential agree well with both simulation and experimental data except at high density and high temperature. Differences between theory and experiment are usually comparable to the differences between two sets of experimental data for the CP potential but are generally larger for the other two potentials. For both BV and RG potentials the excess Helmholtz energies and excess internal energies are up to 15 and 10 per cent higher, respectively, than experimental values whereas the predicted pressures are low by 100-200 bar for RG and 50-100 bar for BV. The BV potential is slightly more satisfactory than the RG potential overall. Results for spherical harmonic components of the radial correlation function for the CP potential calculated using zeroth and first order approximations in the Fischer theory and also in the RAM theory are also compared with results from molecular dynamics simulations.

  12. Local delamination of InSb IRFPAs in liquid nitrogen shock tests (United States)

    Meng, Qingduan; Zhang, Xiaoling; Lv, Yanqiu; Si, Junjie


    Both the local delamination and the local fracture, appearing in the InSb infrared focal plane arrays (IRFPAs) detectors in liquid nitrogen shock tests, restrict the final yield of the InSb IRFPAs detectors. To explore the mechanism of the local delamination appearing in the region of the negative electrode of the InSb IRFPAs detectors, basing on the created structural modeling of the InSb IRFPAs detectors, we obtain the distributions of the interfacial stresses in the different interfaces of the InSb IRFPAs detectors. After comparing the distributions of the simulated interfacial stresses with the measured local delamination region in the InSb IRFPAs detectors, we think that the local delamination originates from the interfacial shear stresses, and the crack extension is the typical sliding mode. Besides, the weakened gluing strength between the InSb chip and the underfill in the negative electrode region also causes this region to be prone to the local delamination. All these findings provide the theoretical references for both the structure design and the structure optimization of the InSb IRFPAs detectors assembly in the future.

  13. Experimental Investigation of Gas Hydrate Production at Injection of Liquid Nitrogen into Water with Bubbles of Freon 134A

    Directory of Open Access Journals (Sweden)

    Meleshkin Anton V.


    Full Text Available The hydrodynamic processes during the injection of the cryogenic liquid into the volume of water with bubbles of gas freon 134a are studding experimentally. A processes during the explosive boiling of liquid nitrogen in the volume of water are registered. Video recording of identified gas hydrate flakes formed during this process is carried out by high speed camera. These results may be useful for the study of the new method of producing gas hydrates, based on the shock-wave method.

  14. Multi-scale full-field measurements and near-wall modeling of turbulent subcooled boiling flow using innovative experimental techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Yassin A., E-mail:


    Highlights: • Near wall full-field velocity components under subcooled boiling were measured. • Simultaneous shadowgraphy, infrared thermometry wall temperature and particle-tracking velocimetry techniques were combined. • Near wall velocity modifications under subcooling boiling were observed. - Abstract: Multi-phase flows are one of the challenges on which the CFD simulation community has been working extensively with a relatively low success. The phenomena associated behind the momentum and heat transfer mechanisms associated to multi-phase flows are highly complex requiring resolving simultaneously for multiple scales on time and space. Part of the reasons behind the low predictive capability of CFD when studying multi-phase flows, is the scarcity of CFD-grade experimental data for validation. The complexity of the phenomena and its sensitivity to small sources of perturbations makes its measurements a difficult task. Non-intrusive and innovative measuring techniques are required to accurately measure multi-phase flow parameters while at the same time satisfying the high resolution required to validate CFD simulations. In this context, this work explores the feasible implementation of innovative measuring techniques that can provide whole-field and multi-scale measurements of two-phase flow turbulence, heat transfer, and boiling parameters. To this end, three visualization techniques are simultaneously implemented to study subcooled boiling flow through a vertical rectangular channel with a single heated wall. These techniques are listed next and are used as follow: (1) High-speed infrared thermometry (IR-T) is used to study the impact of the boiling level on the heat transfer coefficients at the heated wall, (2) Particle Tracking Velocimetry (PTV) is used to analyze the influence that boiling parameters have on the liquid phase turbulence statistics, (3) High-speed shadowgraphy with LED illumination is used to obtain the gas phase dynamics. To account

  15. AC losses of oxide superconducting coils operated in liquid nitrogen; Ekitai chisso reikyaku sankabutsu chodendo koiru no koryu sonshitsu

    Energy Technology Data Exchange (ETDEWEB)

    Fukushige, K.; Hayashida, T.; Sumiyoshi, F.; Kawabata, S. [Kagoshima Univ., Kagoshima (Japan); Hayashi, H. [Kyushu Electric Power Co., Inc., Fukuoka (Japan)


    As a basic research with the aim of practical application of the liquid nitrogen cooling oxide superconductivity coil, the double pancake-shape coil was produced experimentally using Bi system polycore tape wire rod, and the characteristic evaluation was carried out. Especially, it tried to examine the measured value of ac loss in the coil energization using analytical result of magnetic field distribution which is added to coil winding and magnetization loss data of the short length sample. (NEDO)

  16. The influence of cavitation on the flow characteristics of liquid nitrogen through spray nozzles: A CFD study (United States)

    Xue, Rong; Ruan, Yixiao; Liu, Xiufang; Cao, Feng; Hou, Yu


    Spray cooling with cryogen could achieve lower temperature level than refrigerant spray. The internal flow conditions within spray nozzles have crucial impacts on the mass flow rate, particle size, spray angle and spray penetration, thereby influencing the cooling performance. In this paper, CFD simulations based on mixture model are performed to study the cavitating flow of liquid nitrogen in spray nozzles. The cavitation model is verified using the experimental results of liquid nitrogen flow over hydrofoil. The numerical models of spray nozzle are validated against the experimental data of the mass flow rate of liquid nitrogen flow through different types of nozzles including the pressure swirl nozzle and the simple convergent nozzle. The numerical studies are performed under a wide range of pressure difference and inflow temperature, and the vapor volume fraction distribution, outlet vapor quality, mass flow rate and discharge coefficient are obtained. The results show that the outlet diameter, the pressure difference, and the inflow temperature significantly influence the mass flow rate of spray nozzles. The increase of the inflow temperature leads to higher saturation pressure, higher cavitation intensity, and more vapor at nozzle outlet, which can significantly reduce mass flow rate. While the discharge coefficient is mainly determined by the inflow temperature and has little dependence on the pressure difference and outlet diameter. Based on the numerical results, correlations of discharge coefficient are proposed for pressure swirl nozzle and simple convergent nozzles, respectively, and the deviation is less than 20% for 93% of data.

  17. Facile fabrication of palladium-ionic liquids-nitrogen-doped graphene nanocomposites as enhanced electro-catalyst for ethanol oxidation (United States)

    Li, Shuwen; Yang, Honglei; Ren, Ren; Ma, Jianxin; Jin, Jun; Ma, Jiantai


    The palladium-ionic liquids-nitrogen-doped graphene nanocomposites are facile fabricated as enhanced electro-catalyst for ethanol oxidation. First, the ionic liquids functionalized nitrogen-doping graphene nanosheets (PDIL-NGS) with few layers is synthesized through a facile and effective one-pot hydrothermal method with graphene oxide as raw material, urea as reducing-doping agents and ionic liquids (ILs) derived from 3,4,9,10-perylene tetracarboxylic acid as functional molecules. The results of systematic characterization reveal that the PDIL molecules not only can functionalize NGS by π-π stacking with no affecting the nitrogen doping but also prevent the agglomeration of NGS. More importantly, the processing performance and the property of electron transfer are remarkably enhanced duo to introducing a large number of ILs groups. Then, the enhanced electrocatalytic Pd nanoparticles are successfully anchored on PDIL-NGS by a facile and surfactant-free synthetic technique. As an anode catalyst, the novel catalyst exhibits better kinetics, more superior electrocatalytic performance, higher tolerance and electrochemical stability than the other catalysts toward ethanol electrooxidation, owing to the role of PDIL molecules. Therefore, the new catalyst is believed to have the potential use for direct alcohol fuel cells in the future and the functionalized NGS is promising useful materials applied in other fields.

  18. The potential of Mythimna sequax Franclemont eggs for the production of Trichogramma spp. after cryopreservation in liquid nitrogen

    Directory of Open Access Journals (Sweden)

    Magda Fernanda Paixão

    Full Text Available ABSTRACT The cryopreservation of noctuid eggs in liquid nitrogen has proved be a promising tool in the mass production of Trichogramma, however studies into this technique have only just begun. This study evaluated the response of different densities of the female of Trichogramma pretiosum Riley to the parasitism of Mythimna sequax eggs stored and not stored in liquid nitrogen, and the performance of females reared only in cryopreserved eggs. The study evaluated the influence of the number of T. pretiosum females (4, 8 and 12 released to parasitise 40 M. sequax eggs, stored and not stored for 15 days in liquid nitrogen, as well as the performance of T. pretiosum females reared in eggs stored for three generations and females reared in non-stored eggs. Parasitism by T. pretiosum in stored eggs was 84%, twice the value obtained in previous studies. The emergence of parasitoids was greater than 95% in both experiments. The performance of females raised in stored eggs did not differ from that of females raised in non-stored eggs. The data show that the technique of cryopreservation of M. sequax eggs may be a viable alternative in the mass production of T. pretiosum.

  19. Nitrogen incorporation into GaAsN and InGaAsN layers grown by liquid-phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Milanova, Malina; Koleva, Greta; Popov, Georgy [Central Laboratory of Applied Physics, Plovdiv (Bulgaria); Vitanov, Petko [Central Laboratory of Solar Energy and New Energy Sources, Sofia (Bulgaria); Terziyska, Penka [Semiconductor Research Laboratory, Department of Electrical Engineering, Lakehead University, Thunder Bay, ON (Canada)


    This paper presents the comparison of nitrogen incorporation in GaAsN and InGaAsN layers grown on GaAs substrate from Ga- and In-rich solution, respectively, by liquid-phase epitaxy. Polycrystalline GaN has been used as a source of nitrogen in two cases. The initial epitaxy temperature has been varied in the temperature range 600-550 C. Nitrogen content in Ga{sub 1-x}AsN{sub x} grown layers has been determined to be in the range 0.1-0.5%. Higher nitrogen incorporation efficiency has been found for quaternary InGaAsN layers grown under carefully chosen lattice matched conditions. The incorporation of nitrogen into GaAsN and InGaAsN layers has been study by vibrational mode absorption spectroscopy. Nitrogen-induced vibration mode near 472 cm{sup -1} has been registered in GaAsN samples. Preferential In-N bonds and the formation of N-centred In{sub 3}Ga{sub 1} clusters have been identified for lattice matched to GaAs epitaxial InGaAsN layers. Electrical properties of the samples have been characterized by temperature-dependent Hall effect measurements. Nominally undoped GaAsN and InGaAsN grown layers are n-type with Hall concentration about one order of magnitude higher in comparison to layers not containing nitrogen. Thermally activated increase in the free carrier concentration at temperatures higher than 150 K is observed which indicates the presence of N-related deep donor levels below dilute nitride conduction band edge. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Experimental study on the lightning impulse dielectric strength of liquid nitrogen insulation medium according to various pressures (United States)

    Na, J. B.; Kang, H.; Chang, K. S.; Kim, Y. J.; Chu, S. Y.; Kim, T. J.; Kim, K.-J.; Lee, H. G.; Ko, T. K.


    The lightning impulse breakdown characteristics of liquid nitrogen are necessarily considered for designing high voltage superconducting machines required high reliability. This paper investigates the dielectric capability of liquid nitrogen (LN2) to withstand lightning impulse. To gain the dielectric capability of LN2 cryogenic cooling system, lightning impulse was induced in sphere-plane electrode systems which have six different diameters of sphere electrode. The pressure is one of major condition to decide dielectric strength at LN2 cryogenic cooling system. Thus, the gaseous nitrogen was injected to control pressure in the cryostat, ranging from 100 kPa to 200 kPa. Moreover, field utilization factor was calculated between sphere and plane electrode systems by a finite element method analysis. The electric field criterion of LN2 as insulation media was calculated from correlation between the experimental results and the field utilization factor. In the future, these results can be applied as the design parameter of electrical insulation for developing high voltage superconducting machines.

  1. An improved mechanistic critical heat flux model for subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Young Min [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)


    Based on the bubble coalescence adjacent to the heated wall as a flow structure for CHF condition, Chang and Lee developed a mechanistic critical heat flux (CHF) model for subcooled flow boiling. In this paper, improvements of Chang-Lee model are implemented with more solid theoretical bases for subcooled and low-quality flow boiling in tubes. Nedderman-Shearer`s equations for the skin friction factor and universal velocity profile models are employed. Slip effect of movable bubbly layer is implemented to improve the predictability of low mass flow. Also, mechanistic subcooled flow boiling model is used to predict the flow quality and void fraction. The performance of the present model is verified using the KAIST CHF database of water in uniformly heated tubes. It is found that the present model can give a satisfactory agreement with experimental data within less than 9% RMS error. 9 refs., 5 figs. (Author)

  2. Performance enhancement of a heat pump system with ice storage subcooler

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Ming-Jer [Department of Electrical Engineering, Nan-Kai University of Technology, No.568 Chung Cheng Road, Tsao Tun, Nan Tou, Taiwan 54243 (China); Kuo, Yu-Fu; Cheng, Chiao-Hung; Chen, Sih-Li [Department of Mechanical Engineering, National Taiwan University, No.1, Sec.4 Roosevelt Road, Taipei, Taiwan 10617 (China); Shen, Chih-Chiu [Department of Mechanical Engineering, National Chung Hsing University, No.250, Kuo Kuang Road, Taichung, Taiwan 40227 (China)


    This article experimentally investigates the thermal performance of a heat pump system with an ice storage subcooler. The system supplies heating and cooling demands to two greenhouses with temperature ranging 308{proportional_to}323 K and 273{proportional_to}291 K respectively and utilizes an ice storage tank to subcool the condensed refrigerant, which can enhance the system coefficient of performance (COP). The ice storage tank charges for storing ice, when the cooling load is less than the nominal cooling capacity. While the cooling load is larger than the nominal cooling capacity, the ice storage tank discharges for subcooling. The results show that in the charge mode the heat pump COP of ice storage system is 12% higher than that without ice storage tank. Under the discharge mode, the ice storage system provides the refrigerator COP 15% higher than that without ice storage tank. (author)

  3. Automated high-speed video analysis of the bubble dynamics in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Maurus, Reinhold; Ilchenko, Volodymyr; Sattelmayer, Thomas [Technische Univ. Muenchen, Lehrstuhl fuer Thermodynamik, Garching (Germany)


    Subcooled flow boiling is a commonly applied technique for achieving efficient heat transfer. In the study, an experimental investigation in the nucleate boiling regime was performed for water circulating in a closed loop at atmospheric pressure. The test-section consists of a rectangular channel with a one side heated copper strip and a very good optical access. For the optical observation of the bubble behaviour the high-speed cinematography is used. Automated image processing and analysis algorithms developed by the authors were applied for a wide range of mass flow rates and heat fluxes in order to extract characteristic length and time scales of the bubbly layer during the boiling process. Using this methodology, a huge number of bubble cycles could be analysed. The structure of the developed algorithms for the detection of the bubble diameter, the bubble lifetime, the lifetime after the detachment process and the waiting time between two bubble cycles is described. Subsequently, the results from using these automated procedures are presented. A remarkable novelty is the presentation of all results as distribution functions. This is of physical importance because the commonly applied spatial and temporal averaging leads to a loss of information and, moreover, to an unjustified deterministic view of the boiling process, which exhibits in reality a very wide spread of bubble sizes and characteristic times. The results show that the mass flux dominates the temporal bubble behaviour. An increase of the liquid mass flux reveals a strong decrease of the bubble life - and waiting time. In contrast, the variation of the heat flux has a much smaller impact. It is shown in addition that the investigation of the bubble history using automated algorithms delivers novel information with respect to the bubble lift-off probability. (Author)

  4. Physicochemical processes in embryonic plant tissue during the transition to the state of cold anabiosis and storage at liquid nitrogen temperature (United States)

    Khodko, A. T.; Lysak, Yu. S.


    Critical opalescence phenomenon was observed in the cytoplasm of garlic embryonic tissue—meristem—upon cooling in liquid nitrogen vapor, indicating liquid-liquid phase transition in the system. It was established that cells of the meristem tissue survive the cooling-thawing cycle. We suggest that the transition of meristem tissue to the state of anabiosis is mainly due to a drastic slowing of the diffusion in the cytoplasm caused by the passage of the solution through the critical point, followed by the formation of a dispersed system—a highly concentrated emulsion—as a result of a liquid-liquid phase transition. This macrophase separation is characteristic of polymer-solvent systems. We established the regime of cooling down to liquid nitrogen temperature and subsequent thawing in the cryopreservation cycle for the biological object under study, which ensures the preservation of tissue viability.


    Directory of Open Access Journals (Sweden)

    Tomas Romsy


    Full Text Available Subcooled flow boiling under forced convection occurs in many industrial applications of purpose to maximize heat removal from the heat source by the very large heat transfer coefficient. This work deals with CFD simulations of the subcooled flow boiling of refrigerant R12 solved by code ANSYS FLUENT r16. The main objective of this paper is verification of used numerical settings on relevant experiments performed on DEBORA test facility. Also comparisons with previously provided simulation on NRI Rez are presented. Data outputs from this work are basis to subsequent calculations of steam-water mixture cooling of Pb-Li eutectic.

  6. Lap shear strength of selected adhesives (epoxy, varnish, B-stage glass cloth) in liquid nitrogen and at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Froelich, K.J.; Fitzpatrick, C.M.


    The adhesives included several epoxy resins, a varnish, and a B-stage glass cloth (a partially cured resin in a fiberglass cloth matrix). Several parameters critical to bond strength were varied: adhesive and adherend differences, surface preparation, coupling agents, glass cloth, epoxy thickness, fillers, and bonding pressure and temperature. The highest lap shear strengths were obtained with the B-shear glass cloth at both liquid nitrogen and room temperatures with values of approximately 20 MPa (3000 psi) and approximately 25.5 MPa (3700 psi) respectively.

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

    DEFF Research Database (Denmark)

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


    of a superconducting cable includes the thermal insulation of the cable, the current- and coolant feed-throughs and possibly dynamic vacuum control. Since feed-throughs represent major sources of heat in-leak to the cryogenic system it is important to optimise the design and the number of these in a superconducting...... cable. We report on our experimental set-up for testing a 10 meter long high temperature superconducting cable with a critical current of 3.2 kA at 77K. The set-up consists of a custom designed cable end termination, current lead, coolant feed-through, liquid nitrogen closed loop circulation system...

  8. Effect of liquid nitrogen freezing and subsequent storage on survival of Staphylococcus aureus and Streptococcus pyogenes in treated prawn meat


    Chakrabarti, R.; Choudhury, D.R.


    Prawn meat treated with Streptococcus pyogenes B-49-2 culture and Staphylococcus aureus ATCC-12598 culture were frozen in conventional plate freezer at -40°C and by spray type liquid nitrogen freezer. The frozen products were stored at -18°C. Streptococcus pyogenes B-49-2 showed low sensitivity to cold injury during freezing and frozen storage. Staphylococcus aureus ATCC-12598 survived during the entire storage period of 240 days. Total bacterial count of untreated prawn meat was found to be ...

  9. Comparison of heat transfer in liquid and slush nitrogen by numerical simulation of cooling rates for French straws used for sperm cryopreservation. (United States)

    Sansinena, M; Santos, M V; Zaritzky, N; Chirife, J


    Slush nitrogen (SN(2)) is a mixture of solid nitrogen and liquid nitrogen, with an average temperature of -207 °C. To investigate whether plunging a French plastic straw (commonly used for sperm cryopreservation) in SN(2) substantially increases cooling rates with respect to liquid nitrogen (LN(2)), a numerical simulation of the heat conduction equation with convective boundary condition was used to predict cooling rates. Calculations performed using heat transfer coefficients in the range of film boiling confirmed the main benefit of plunging a straw in slush over LN(2) did not arise from their temperature difference (-207 vs. -196 °C), but rather from an increase in the external heat transfer coefficient. Numerical simulations using high heat transfer (h) coefficients (assumed to prevail in SN(2)) suggested that plunging in SN(2) would increase cooling rates of French straw. This increase of cooling rates was attributed to a less or null film boiling responsible for low heat transfer coefficients in liquid nitrogen when the straw is placed in the solid-liquid mixture or slush. In addition, predicted cooling rates of French straws in SN(2) tended to level-off for high h values, suggesting heat transfer was dictated by heat conduction within the liquid filled plastic straw. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Effects of Different Application Methods of Methane Fermentation Digested Liquid into the Paddy Plot on Soil Nitrogen Behavior and Rice Yield (United States)

    Watanabe, Satoko; Nakamura, Kimihito; Seok Ryu, Chan; Iida, Michihisa; Kawashima, Shigeto

    Methane fermentation technique with the treatment of animal waste and food waste is drawing public attention as a good option for the utilization of biomass resources and it is investigated how to apply the by-product of fermentation (methane fermentation digested liquid) to agricultural fields as a fertilizer. It is important to determine an adequate method of applying digested liquid to a paddy plot as fertilizer taking into account the concentrations of soil nitrogen components and rice yield. The objective of this study is to compare the performances of three methods of applying digested liquid to paddy plots in terms of the nitrogen transformation in soil, rice yield, and nitrogen load in effluent. The three methods were pouring (with irrigation water), spreading onto the surface of a plot, and injection into paddy soil. It was found that the ammonium nitrogen concentration and the dissolved organic nitrogen concentration in soil of the spreading plot were higher than that for the pouring plot and that for the injecting plot. The rice yield was higher in the spreading plot than in the injecting and pouring plots. And, there was a significant correlation between the rice yield and the dissolved organic nitrogen just before and after the panicle initiation stage. There were no differences in the nitrogen effluent loads with surface drainage.

  11. Influence of sub-cooling on the energy performance of two ...

    African Journals Online (AJOL)

    Influence of sub-cooling on the energy performance of two ecofriendly R22 alternative refrigerants. ... Journal of Science and Technology (Ghana) ... They also exhibited lower power per ton of refrigeration (PPTR) than that of R22, but R433A emerged as the most energy efficient refrigerant among all the investigated ...


    Cejas, Inaudis; Rivas, Maribel; Nápoles, Lelurlys; Marrero, Pedro; Yabor, Lourdes; Aragón, Carlos; Pérez, Aurora; Engelmann, Florent; Martínez-Montero, Marcos Edel; Lorenzo, José Carlos


    It is well known that cryopreserving seeds with high water content is detrimental to survival, but biochemical and structural parameters of cryostored hydrated common bean seeds have not been published. The objective of this work was to study the effect of liquid nitrogen exposure on selected biochemical and structural parameters of hydrated Phaseolus vulgaris seeds. We cryopreserved seeds at various moisture contents and evaluated: germination; electrolyte leakage; fresh seed weight; levels of chlorophyll pigments, malondialdehyde, other aldehydes, phenolics and proteins; thickness of cotyledon epidermis, parenchyma, and starch storage parenchyma; and radicle and plumule lengths. Germination was totally inhibited when seeds were immersed in water for 50 min (moisture content of 38%, FW basis) before cryopreservation. The combined effects of seed water imbibition and cryostorage decreased phenolics (free, cell wall-linked, total), chlorophyll a and protein content. By contrast, electrolyte leakage and levels of chlorophyll b and other aldehydes increased as a result of the combination of these two experimental factors. These were the most significant effects observed during exposure of humid seed to liquid nitrogen. Further studies are still required to clarify the molecular events taking place in plant cells during cryostorage.

  13. Comparison of surgical blade and cryosurgery with liquid nitrogen techniques in treatment of physiologic gingival pigmentation: short term results. (United States)

    Rahmati, Saeed; Darijani, Mansoore; Nourelahi, Maryam


    Melanin pigmentation of the gingiva is a crucial esthetic problem. A variety of methods have been used for gingival depigmentation. The purpose of this study was to compare the results of two treatment modalities: scalpel technique and cryotherapy with liquid nitrogen in treatment of gingival pigmentation. Twenty patients with chief complaint of gingival pigmentation participated in our study. 10 patients were treated with cryotherapy and remaining 10 participants were undergone the scalpel technique surgery. We evaluated acquiescence and comfort of the patients, degree of depigmentation, based on the area of pigmentation shown by gridlines option in Microsoft Paint software, and the presence or absence of gingival recession before and one month after treatment. Data was analyzed using Mann-Whitney and Chi-Square tests. A significance level of p≤ 0.05 was adopted. Mean value and standard deviation of depigmentation for group A and group B was 96.17±2.51 and 95±2.48, respectively. The difference was not statistically significant (p= 0.225). There was no association between the treatment modality and the gingival recession (p= 0.303) or the treatment modality and the patient satisfaction (p= 0.346). No significant difference was found between gingival recession measures before and after the operation in the two treatment modalities. Surgical blade and cryosurgery with liquid nitrogen had no significant difference in treatment of physiologic gingival pigmentation. Both Techniques are acceptable in the treatment of gingival pigmentation.

  14. Electrical conductivity and equation of state of liquid nitrogen, oxygen, benzene, and 1-butene shocked to 60 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, D.C.


    Measurements are reported for the electrical conductivity of liquid nitrogen (N/sub 2/), oxygen (O/sub 2/) and benzene (C/sub 6/H/sub 6/), and Hugoniot equation of state of liquid 1-butene (C/sub 4/H/sub 8/) under shock compressed conditions. The conductivity data span 7 x 10/sup -4/ to 7 x 10/sup 1/ ..cap omega../sup -1/cm/sup -1/ over a dynamic pressure range 18.1 to 61.5 GPa and are discussed in terms of amorphous semiconduction models which include such transport phenomena as hopping, percolation, pseudogaps, and metallization. Excellent agreement is found between the equation-of-state measurements, which span a dynamic pressure range 12.3 to 53.8 GPa, and Ree's calculated values which assume a 2-phase mixture consisting of molecular hydrogen and carbon in a dense diamond-like phase. There is a 2-1/2 fold increase in the thermal pressure contribution over a less dense, stoichiometrically equivalent liquid. 90 refs., 48 figs., 8 tabs.

  15. Inorganic chemistry: Direct syntheses from pure liquid SO3 and from trivalent and pentavalent nitrogen derivatives (United States)

    Vandorpe, B.; Heubel, J.


    From pure liquid SO3 direct synthesis reactions were carried out with N2O5, NO2Cl, NOCl which yielded N2O54SO3, 3SO3, 2SO3-NO2Cl2SO3-NOCl2SO3 and NOCl2SO3, the latter being obtained for the first time in the pure state. In all cases the crystallized product was obtained by separating the constituents of the mixture and then going through a single viscous liquid phase.

  16. Subcooled boiling-induced vibration of a heater rod located between two metallic walls

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Kenji, E-mail:; Hashimoto, Yusuke; Kunugi, Tomoaki; Yokomine, Takehiko; Kawara, Zensaku


    Highlights: • A heating structure in water vibrates itself due to subcooled boiling (SBIV). • Experiments with a heater rod located between two metallic walls were conducted. • Large bubbles growing in 1 mm-gap distance with each wall influenced on the SBIV. • Frequency of large bubble generation corresponded to acceleration of the heater rod. • Acceleration of the heater rod in the direction towards each wall was encouraged. - Abstract: The phenomenon that a heating structure vibrates itself due to the behavior of vapor bubbles generated under subcooled boiling has been known as “Subcooled Boiling-induced Vibration (SBIV)”. As one of such a heating structure, fuel assemblies for Boiling Water Reactors (BWR) are utilized in subcooled boiling of water, and those for Pressurized Water Reactors (PWR) may face unexpected subcooled boiling conditions in case of sudden drop of the system pressure or loss of water flow, though they are utilized in single phase of water under normal operating conditions. As studies on SBIV, some researchers have conducted demonstrative experiments with a partial array of fuel rods simulating the actual BWR fuel assembly in a flow test loop, which showed no significant influences of the SBIV to degrade the integrity of the fuel rods. In addition, in order to investigate the fundamental phenomenon of the SBIV, pool boiling experiments of the SBIV on a single heater rod were performed in other studies with a simplified apparatus of a water tank in laboratory size under atmospheric pressure. In the experiments, behavior of bubbles generated under various degree of subcooling were observed, and the acceleration of the SBIV of the heater rod was measured. The present study, as a series of the above experiments for the fundamental phenomenon of the SBIV, the two thin walls made of stainless steel were installed in parallel to interleave the heater rod with the gap distance of 1 mm or 3 mm to each of the two walls, which was expected

  17. Nitrification in a completely stirred tank reactor treating the liquid phase of digestate: The way towards rational use of nitrogen. (United States)

    Svehla, Pavel; Radechovska, Helena; Pacek, Lukas; Michal, Pavel; Hanc, Ales; Tlustos, Pavel


    The nitrification of the liquid phase of digestate (LPD) was conducted using a 5L completely stirred tank reactor (CSTR) in two independent periods (P1 - without pH control; P2 - with pH control). The possibility of minimizing nitrogen losses during the application of LPD to the soil as well as during long-term storage or thermal thickening of LPD using nitrification was discussed. Moreover, the feasibility of applying the nitrification of LPD to the production of electron acceptors for biological desulfurization of biogas was assessed. Despite an extremely high average concentration of ammonia and COD in LPD reaching 2470 and 9080mg/L, respectively, nitrification was confirmed immediately after the start-up of the CSTR. N-NO3- concentration reached 250mg/L only two days after the start of P1. On the other hand, P1 demonstrated that working without pH control is a risk because of the free nitrous acid (FNA) inhibition towards nitrite oxidizing bacteria (NOB) resulting in massive nitrite accumulation. Up to 30.9mg/L of FNA was present in the reactor during P1, where the NOB started to be inhibited even at 0.15mg/L of FNA. During P2, the control of pH at 7.0 resulted in nitrogen oxidation efficiency reaching 98.3±1.5% and the presence of N-NO3- among oxidized nitrogen 99.6±0.4%. The representation of volatile free ammonia within total nitrogen was reduced more than 1000 times comparing with raw LPD under these conditions. Thus, optimum characteristics of the tested system from the point of view of minimizing the nitrogen losses as well as production of electron acceptors for the desulfurization of biogas were gained in this phase of reactor operation. Based on the results of the experiments, potential improvements and modifications of the tested system were suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. GreenChill Store Certification Protocol for Sub-Cooling Contained on Racks Separate from Refrigeration Equipment (United States)

    Document describes the protocol used to determine the total load and refrigerant charge of stores that have placed all sub-cooling on a rack separate from all other commercial refrigeration equipment.

  19. Thermodynamics of Aluminum, Nitrogen and AlN formation in Liquid Iron

    National Research Council Canada - National Science Library

    Kim, Wan-Yi; Kang, Jin-Goo; Park, Chul-Hwan; Lee, Joong-Beom; Pak, Jong-Jin


    ... self interaction parameter of aluminum, and the equilibrium constant for the formation of pure solid AlN in liquid iron as follows.eNAl=−332.2/T+0.194eAlAl=111.0/T−0.016AlN (s)=Al+Nlog KAlN=−16 560/T+...

  20. Histopathological analysis of the therapeutic response to cryotherapy with liquid nitrogen in patients with multiple actinic keratosis. (United States)

    Oliveira, Marina Câmara de; Trevisan, Flávia; Pinto, Clovis Antônio Lopes; Xavier, Célia Antônia; Pinto, Jaqueline Campoi Calvo Lopes


    Actinic keratoses are premalignant lesions of the skin caused by excessive sun exposure. Lesions may become mainly squamous cell carcinoma. Cryotherapy with liquid nitrogen is one of the main treatments. In order to evaluate the response of actinic keratosis to cryotherapy by histopathology, two lesions were selected in each of 14 patients with multiple actinic keratoses. In one lesion a biopsy was performed and in the other lesion a biopsy was performed after cryotherapy. Subsequently, both biopsies were compared histologically. Of the thirteen patients who completed the study, the best results were obtained in lesions undergoing cryotherapy concerning the atypia of keratinocytes, epithelial thickness and corneal layer and lymphocytic infiltrate. Despite the small number of patients, it was concluded that, if performed correctly, cryotherapy has high efficacy in the treatment of actinic keratoses.

  1. Large magnetic entropy change of Gd-based ternary bulk metallic glass in liquid-nitrogen temperature range (United States)

    Fu, H.; Zhang, X. Y.; Yu, H. J.; Teng, B. H.; Zu, X. T.


    Gd 60Co 26Al 14 bulk metallic glass (BMG) with a diameter of 3 mm was prepared by arc-melting and copper-mold suck-casting. X-ray diffraction (XRD) results show that the as-cast Gd 60Co 26Al 14 rod consists of a wholly amorphous phase. Differential scanning calorimetry (DSC) measurements indicated that one glass transition temperature (Tg) and two crystallization temperatures (TX) occur at 570, 602, and 642 K, respectively. Moreover, two Curie temperatures of 82 and 128 K, which correspond to the two amorphous phases in the DSC trace, were determined from the thermo-magnetization curve. The maximal magnetic entropy change (ΔSM) under 0-5 T is about 10.1 J/kg K at 75 K and the refrigerant capacity (RC) is about 556 J/kg, which makes Gd 60Co 26Al 14 BMG a promising candidate for magnetic refrigerant near liquid-nitrogen temperatures.

  2. Nitrogen-Doped Porous Carbons from Ionic Liquids@MOF: Remarkable Adsorbents for Both Aqueous and Nonaqueous Media. (United States)

    Ahmed, Imteaz; Panja, Tandra; Khan, Nazmul Abedin; Sarker, Mithun; Yu, Jong-Sung; Jhung, Sung Hwa


    Porous carbons were prepared from a metal-organic framework (MOF, named ZIF-8), with or without modification, via high-temperature pyrolysis. Porous carbons with high nitrogen content were obtained from the calcination of MOF after introducing an ionic liquid (IL) (IL@MOF) via the ship-in-bottle method. The MOF-derived carbons (MDCs) and IL@MOF-derived carbons (IMDCs) were characterized using various techniques and used for liquid-phase adsorptions in both water and hydrocarbon to understand the possible applications in purification of water and fuel, respectively. Adsorptive performances for the removal of organic contaminants, atrazine (ATZ), diuron, and diclofenac, were remarkably enhanced with the modification/conversion of MOFs to MDC and IMDC. For example, in the case of ATZ adsorption, the maximum adsorption capacity of IMDC (Q 0 = 208 m 2 /g) was much higher than that of activated carbon (AC, Q 0 = 60 m 2 /g) and MDC (Q 0 = 168 m 2 /g) and was found to be the highest among the reported results so far. The results of adsorptive denitrogenation and desulfurization of fuel were similar to that of water purification. The IMDCs are very useful in the adsorptions since these new carbons showed remarkable performances in both the aqueous and nonaqueous phases. These results are very meaningful because hydrophobic and hydrophilic adsorbents are usually required for the adsorptions in the water and fuel phases, respectively. Moreover, a plausible mechanism, H-bonding, was also suggested to explain the remarkable performance of the IMDCs in the adsorptions. Therefore, the IMDCs derived from IL@MOF might have various applications, especially in adsorptions, based on high porosity, mesoporosity, doped nitrogen, and functional groups.

  3. Prediction of forced convective heat transfer and critical heat flux for subcooled water flowing in miniature tubes (United States)

    Shibahara, Makoto; Fukuda, Katsuya; Liu, Qiusheng; Hata, Koichi


    The heat transfer characteristics of forced convection for subcooled water in small tubes were clarified using the commercial computational fluid dynamic (CFD) code, PHENICS ver. 2013. The analytical model consists of a platinum tube (the heated section) and a stainless tube (the non-heated section). Since the platinum tube was heated by direct current in the authors' previous experiments, a uniform heat flux with the exponential function was given as a boundary condition in the numerical simulation. Two inner diameters of the tubes were considered: 1.0 and 2.0 mm. The upward flow velocities ranged from 2 to 16 m/s and the inlet temperature ranged from 298 to 343 K. The numerical results showed that the difference between the surface temperature and the bulk temperature was in good agreement with the experimental data at each heat flux. The numerical model was extended to the liquid sublayer analysis for the CHF prediction and was evaluated by comparing its results with the experimental data. It was postulated that the CHF occurs when the fluid temperature near the heated wall exceeds the saturated temperature, based on Celata et al.'s superheated layer vapor replenishment (SLVR) model. The suggested prediction method was in good agreement with the experimental data and with other CHF data in literature within ±25%.

  4. Sensitivity Analysis of RCW Temperature on the Moderator Subcooling Margin for the LBLOCA of Wolsong NPP Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Si Won; Kim, Jong Hyun; Choi, Sung Soo [Atomic Creative Technology Co., Daejeon (Korea, Republic of); Kim, Sung Min [Central Research Institute, Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)


    Moderator subcooling margin has been analyzed using the MODTURC{sub C}LAS code in the Large LOCA FSAR PARTs C and F. Performance of moderator heat exchangers depends on RCW (Raw reCirculated Water) temperature. And also the temperature is affected by sea water temperature. Unfortunately, sea water temperature is gradually increasing by global warming. So it will cause increase of RCW temperature inevitably. There is no assessment result of moderator subcooling with increasing RCW temperature even if it is important problem. Therefore, sensitivity analysis is performed to give information about the relation between RCW temperature and moderator subcooling in the present study. The moderator subcooling margin has to be ensured to establish the moderator heat removal when Large LOCA with LOECI and Loss of Class IV Power occurs. However, sea water temperature is increasing gradually due to global warming. So it is necessary that sensitivity analysis of RCW temperature on the moderator subcooling margin to estimate the availability of the moderator heat removal. In the present paper, the moderator subcooling analysis is performed using the same methodology and assumptions except for RCW temperature used in FSAR Large LOCA PART F.

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

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


    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.

  6. Hydrophobic recovery of repeatedly plasma-treated silicone rubber .2. A comparison of the hydrophobic recovery in air, water, or liquid nitrogen

    NARCIS (Netherlands)

    Everaert, EP; VanderMei, HC; Busscher, HJ


    Surfaces of medical grade silicone rubber (Q7-4750, Dow Coming) were modified by repeated (six times) RF plasma treatments using various discharge gases: oxygen, argon, carbon dioxide, and ammonia. The treated samples were stored for a period of 3 months in ambient air, water, or liquid nitrogen.

  7. Chemical bonding between antimony and ionic liquid-derived nitrogen-doped carbon for sodium-ion battery anode (United States)

    Xu, Xin; Si, Ling; Zhou, Xiaosi; Tu, Fengzhang; Zhu, Xiaoshu; Bao, Jianchun


    Antimony has received a great deal of attention as a promising anode material for sodium-ion batteries (SIBs) due to its high theoretical capacity of 660 mAh g-1. However, this application is significantly hampered by inherent large volume change and sluggish kinetics. To address these issues, an antimony-cyano-based ionic liquid-derived nitrogen-doped carbon (Sbsbnd CNC) hybrid is proposed and synthesized by ball-milling and subsequent pyrolysis treatment. As an anode material for SIBs, the as-synthesized Sbsbnd CNC hybrid delivers reversible capacities of 475 mAh g-1 at a current density of 100 mA g-1 and 203 mAh g-1 at 5000 mA g-1, and a 92.4% capacity retention based on the first-cycle capacity after 150 cycles at 100 mA g-1. Using ex situ X-ray photoelectron spectroscopy and elemental mapping techniques, we attribute the good structural integrity to the formation of Sbsbnd Nsbnd C bonds between Sb and the cyano-based ionic liquid-derived N-doped carbon matrix. Moreover, the presence of N-doped carbon network in the hybrid material serves as a robust protective cover and an electrical highway, buffering the substantial volume expansion of Sb nanoparticles and ensuring the fast electron transport for stable cycling operation.

  8. Effect of local phenomena on subcooled boiling oscillations in natural circulation boiling loop

    Energy Technology Data Exchange (ETDEWEB)

    Karmakar, Arnab [Birla Institute of Technology, Mesra, Jharkhand 835215 (India); Dey, Runa [Indian School of Mines, Dhanbad, Jharkhand 826004 (India); Paruya, Swapan, E-mail: [National Institute of Technology, Durgapur, West Bengal 713209 (India)


    Highlights: • The estimations of bubble frequency and oscillation of local void fraction α in a natural circulation boiling loop. • The effect of inlet subcooling on the bubble frequency and the oscillations of local α and local pressure. • Effect of local dynamic phenomena on the system oscillations in terms of loop flow rate. • The α-oscillations due to the presence of large bubbles trigger the high-amplitude system-oscillations with a time delay. - Abstract: In this paper, the authors report the estimations of bubble frequency and oscillation of local void fraction and their role in subcooled boiling oscillations in a low-pressure natural circulation boiling loop. The estimations primarily rely on the measurements of impedance using inductance L–capacitance C–resistance R (LCR) meter. The bubble frequencies determined from the impedance signals and the images are comparable. The effect of inlet subcooling on the bubble frequency and the oscillation of local void fraction has been studied and found to be remarkable. Based on the comparison of the oscillations of local void fraction, local pressure and loop flow rate, the effect of local dynamic phenomena on the system oscillations clearly demonstrates that the oscillations of void fraction trigger high-amplitude flow oscillations with a delay between the oscillations of void fraction and loop flow rate.

  9. High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Sanchez, Fernando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)]. E-mail:; Eliosa-Jimenez, Gaudencio [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Silva-Oliver, Guadalupe [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Godinez-Silva, Armando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)


    In this work, new (vapor + liquid) equilibrium data for the (N{sub 2} + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N{sub 2} + n-heptane) system.

  10. Oxides of Nitrogen Emissions from the Combustion of Monodisperse Liquid Fuel Sprays. Ph.D. Thesis (United States)

    Sarv, H.


    A study of NO sub x formation in a one dimensional monodisperse spray combustion system, which allowed independent droplet size variation, was conducted. Temperature, NO and NO sub x concentrations were measured in the transition region, encompassing a 26 to 74 micron droplet size range. Emission measurements of hydrocarbons, carbon monoxide, carbon dioxide and oxygen were also made. The equivalence ratio was varied between 0.8 and 1.2 for the fuels used, including methanol, isopropanaol, n-heptane and n-octane. Pyridine and pyrrole were added to n-heptane as nitrogen-containing additives in order to simulate synthetic fuels. Results obtained from the postflame regions using the pure fuels indicate an optimum droplet size in the range of 43 to 58 microns for minimizing NO sub x production. For the fuels examined, the maximum NO sub x reductions relative to the small droplet size limit were about 10 to 20% for lean and 20 to 30% for stoichiometric and rich mixtures. This behavior is attributed to droplet interactions and the transition from diffusive to premixed type of burning. Preflame vaporization controls the gas phase stoichiometry which has a significant effect on the volume of the hot gases surrounding a fuel droplet, where NO sub x is formed.

  11. Insulation effect on thermal stability of Coated Conductors wires in liquid nitrogen (United States)

    Rubeli, Thomas; Dutoit, Bertrand; Martynova, Irina; Makarevich, Artem; Molodyk, Alexander; Samoilenkov, Sergey


    Superconducting wires are not perfectly homogeneous in term of critical current as well as stabilization. In resistive fault current limiter applications this could lead to hot spots if the fault current is only slightly above the nominal current of the device. Increasing stabilization by using thicker silver coating for example may prevent this problem but this method implies longer wire length to maintain the same impedance during a fault. Very efficient cooling in another way to prevent hot spots, this can be achieved in nucleate boiling regime. Optimal insulation can be used to prevent film boiling regime, staying in nucleate boiling regime in a much broader temperature range. In this work a novel technique is used to monitor in real time the temperature of the wire during the quench. Using this method several increasing insulation thicknesses are tested, measuring for each the heat exchange rate to the nitrogen bath. Exchange rate measurements are made in quasistatic regime and during the re-cooling of the wire. SuperOx wires provided with different insulation thicknesses exhibit an excellent stability, far above a bare wire. On the other side, for very thick insulations the stability gain is lost. Re-cooling speeds dependency on insulation thicknesses is measured too.

  12. Thermal Performance of Low Layer Density Multilayer Insu1ation Using Liquid Nitrogen (United States)

    Johnson, Wesley L.; Fesmire, James E.


    In order to support long duration cryogenic propellant storage, the Cryogenic Fluid Management (CFM) Project of the Exploration Technology Development Program (ETDP) is investigating the long duration storage propertie$ of liquid methane on the lunar surface. The Methane Lunar Surface Thermal Control (MLSTC) testing is using a tank of the approximate dimensions of the Altair ascent tanks inside of a vacuum chamber to simulate the environment in low earth orbit and on the lunar surface. The thermal performance testing of multilayer insulation (MLI) coupons that are fabricated identically to the tank applied insulation is necessary to understand the performance of the blankets and to be able to predict the performance of the insulation prior to testing. This coupon testing was completed in Cryostat-100 at the Cryogenics Test Laboratory. The results showed the properties of the insulation as a function of layer density, number of layers, and warm boundary temperature. These results aid in the understanding of the performance parameters o fMLI and help to complete the body of literature on the topic.

  13. Investigation of transient chill down phenomena in tubes using liquid nitrogen (United States)

    Shukla, A. K.; Sridharan, Arunkumar; Atrey, M. D.


    Chill down of cryogenic transfer lines is a crucial part of cryogenic propulsion as chill down ensures transfer of single phase fluid to the storage tanks of cryogenic engines. It also ensures single phase liquid flow at the start of the engine. Chill down time depends on several parameters such as length of the pipe, pipe diameter, orientation, mass flux etc. To understand the effect of these parameters, experiments are carried out in a set up designed and fabricated at Indian Institute of Technology Bombay using tubes of two different diameters. Experiments are conducted at different inlet pressures and mass flow rate values to understand their effect. Two different pipe sizes are taken to study the effect of variation in diameter on chill down time and quantity of cryogen required. Different orientations are taken to understand their effect on the chill down time, heat transfer coefficient and critical heat flux for the same inlet pressure and mass flux. Pipe inner wall temperature, heat transfer coefficient for different boiling regimes and critical heat flux are calculated based on measured outer surface temperature history for each case. A one dimensional energy conservation equation is solved for transient chill down process considering constant mass flux and inlet pressure to predict the chill down time. Temperature variation during chill down obtained from the numerical simulations are compared with the measured temperature history.

  14. Experimental and analytical studies on a foam insulated rigid type transfer line for use with liquid nitrogen (United States)

    Patidar, Jyotish; Sumanth, R. A.; Behera, Upendra; Kasthurirengan, Srinivasan


    The transfer line is one of the important components of any cryogenic system needed to transport the cryogenic fluid from one location to another. Towards our efforts to develop a long rigid-type transfer line for liquid nitrogen (LN2) to transfer this fluid from a 5000 litre capacity vertical storage tank to the Helium liquefier (Linde Model 1610) located at a distance of nearly 50 m, we designed and fabricated several units of straight section transfer lines of length ≈ 6.5 m and they were integrated to make the long length transfer line. Each unit was fabricated with 0.5 inch dia. copper inner tube supported by spacers within 2 inch dia. PVC outer tube. Each section was foam insulated after the necessary instrumentation for temperature measurements. The individual sub units were integrated together with a small bellow section in between to take care of thermal contraction during use. We present here the analytical and experimental studies of the cool down and mass flow characteristics of a single foam insulated unit. These experimental studies are representative results of the performances of the long length rigid foam insulated transfer line.

  15. Magnetic properties measurement and discussion of an amorphous power transformer core at room and liquid nitrogen temperature (United States)

    Pronto, A. G.; Maurício, A.; Pina, J. M.


    In energy generation, transmission and distribution systems, power transformers are one of the most common and important components. Consequently, the performance of these transformers is crucial to global efficiency of the systems. To optimize transformers efficiency, the selection of an adequate ferromagnetic material is very important. For example, the use of amorphous ferromagnetic materials in transformer cores, replacing crystalline electrical steels, decreases total magnetic losses of the device. Other possible solution to increase energy systems efficiency, is the installation of high temperature superconducting power transformers (HTS transformers), normally cooled by liquid nitrogen at 77 K. In order to contribute to HTS transformer efficiency improvement, a 562.5 VA transformer with an amorphous ferromagnetic core was designed and built. For this core, the most important magnetic properties are measured at room and cryogenic temperature, and then compared with those of a typical crystalline grain-oriented electrical steel. Amorphous material magnetic losses (static and dynamic) at room and 77K are also presented and discussed.

  16. Numerical Study of Evaporation and Motion Characteristics of Liquid Nitrogen Droplet in High-Speed Gas Flow (United States)

    Ruan, Y.; Chen, L.; Liu, X.; Chen, S.; Hou, Y.


    In the cryogenic wind tunnel, cooling the circulating gas to cryogenic temperature by spraying liquid nitrogen (LN2) is an efficient way to increase the Reynolds number. The evaporation and motion of LN2 droplets in the high-speed gas flow is the critical process that determines the cooling rate, cooling capacity and the safe operation of the down-stream compressor. In this study, a numerical model of droplet motion and evaporation in high-speed gas flow is developed and verified against experimental data. The droplet evaporation rate, diameter and velocity are obtained during the evaporation process under different gas temperatures and flow velocities. The results show that the gas temperature has dominant influence on the droplet evaporation rate. High flow speed can increase droplet evaporation effectively at the beginning process. Evaporation of droplets with different diameters follows a similar trend. The absolute evaporation rate increases with the increase of droplet diameter while the relative evaporation amount is highest for the smallest droplet due to its high area-volume ratio. This numerical study provides insight for understanding the evaporation of LN2 droplets in high-speed gas flow and useful guidelines for the design of LN2 spray cooling.

  17. Analysis of an explosion accident of nitrogen trichloride in a waste liquid containing ammonium ion and platinum black. (United States)

    Okada, Ken; Akiyoshi, Miyako; Ishizaki, Keiko; Sato, Hiroyasu; Matsunaga, Takehiro


    Five liters of sodium hypochlorite aqueous solution (12 mass%) was poured into 300 L of liquid waste containing ammonium ion of about 1.8 mol/L in a 500 L tank in a plant area; then, two minutes later the solution exploded with a flash on March 30th, 2005. The tank cover, the fluorescent lamp and the air duct were broken by the blast wave. Thus, we have conducted 40 runs of laboratory-scale explosion tests under various conditions (solution concentrations of (NH4)2SO4 and NaClO, temperatures, Pt catalysts, pH, etc.) to investigate the causes for such an explosion. When solutions of ammonium sulfate and sodium hypochlorite are mixed in the presence of platinum black, explosions result. This is ascribable to the formation of explosive nitrogen trichloride (NCl3). In the case where it is necessary to mix these 2 solutions (ammonium sulfate and sodium hypochlorite) in the presence of platinum black, the following conditions would reduce a probability of explosion; the initial concentration of NH4(+) should be less than 3 mol/L and the pH should be higher than 6. The hypochlorite solution (in 1/10 in volume) to be added at room temperature is recommended to be less than 0.6 mol/L. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Comparison of recurrent rate of gingival pigmentation after treatment by liquid nitrogen and cryoprob in 18 months follows-up

    Directory of Open Access Journals (Sweden)

    Shirin Amini Sedeh


    Full Text Available Background: Cryosurgery is one of the simplest, most effective gingival depigmentation methods. Repigmentation may happen after a while in each method. The aim of this study is to compare the recurrence rate after treatment by liquid nitrogen swap and a cryoprob in 18 months. Materials and Methods: A total of 26 patients with physiologic gingival pigmentation were selected. The anterior sextant was divided into left and right segments; each segment was treated randomly by swap technique or cryoprob. Standard photos were evaluated with photoshop software (Red, Green, Blue, Cyan, Magenta, Yellow, Black [RGB, CMYK] before and at 2 week, 1, 3, 6, 9, 12, 15, 18 months after the treatment. The results were compared, by the independent t-test and repeated measure ANOVA thereafter least significant difference post-hoc. The viewpoints of patients and physicians regarding the treatment outcomes were obtained by a questionnaire and consequently evaluated qualitatively by McNemar test (P 0.05. The mean values of CMYK significantly decreased after 2 weeks in both methods (P 0.05. Qualitative evaluation showed the preference of the cryosurgery with swap method (P < 0.001. No significant recurrence was observed during 18 months follow-up. Conclusion: Both methods of cryosurgery are appropriate in treatment of gingival depigmentation because no significant recurrence was observed during 18 months follow-up.

  19. Comparison of recurrent rate of gingival pigmentation after treatment by liquid nitrogen and cryoprob in 18 months follows-up. (United States)

    Sedeh, Shirin Amini; Badihi, Saba; Esfahaniyan, Vahid


    Cryosurgery is one of the simplest, most effective gingival depigmentation methods. Repigmentation may happen after a while in each method. The aim of this study is to compare the recurrence rate after treatment by liquid nitrogen swap and a cryoprob in 18 months. A total of 26 patients with physiologic gingival pigmentation were selected. The anterior sextant was divided into left and right segments; each segment was treated randomly by swap technique or cryoprob. Standard photos were evaluated with photoshop software (Red, Green, Blue, Cyan, Magenta, Yellow, Black [RGB, CMYK]) before and at 2 week, 1, 3, 6, 9, 12, 15, 18 months after the treatment. The results were compared, by the independent t-test and repeated measure ANOVA thereafter least significant difference post-hoc. The viewpoints of patients and physicians regarding the treatment outcomes were obtained by a questionnaire and consequently evaluated qualitatively by McNemar test (P 0.05). The mean values of CMYK significantly decreased after 2 weeks in both methods (P 0.05). Qualitative evaluation showed the preference of the cryosurgery with swap method (P gingival depigmentation because no significant recurrence was observed during 18 months follow-up.

  20. A liquid nitrogen-free preconcentration unit for measurements of ambient N2O isotopomers by QCLAS (United States)

    Mohn, J.; Guggenheim, C.; Tuzson, B.; Vollmer, M. K.; Toyoda, S.; Yoshida, N.; Emmenegger, L.


    Important information about the biogeochemical cycle of nitrous oxide (N2O) can be obtained by measuring its three main isotopic species, 14N15N16O, 15N14N16O, and 14N14N16O, and the respective site-specific relative isotope ratio differences δ15Nα and δ15Nβ. Absorption laser spectroscopy in the mid-infrared is a direct method for the analysis of the 15N isotopic composition of N2O, yet not sensitive enough for atmospheric N2O mixing ratios (320 ppb). To enable a fully-automated high precision analysis of N2O isotopic species at ambient mixing ratios, we built and optimized a liquid nitrogen-free preconcentration unit to be coupled to a quantum cascade laser (QCL) based spectrometer. During standard operation 10 l of ambient air are preconcentrated on a HayeSep D trap and desorbed in 50 ml of synthetic air. Rigorous tests were conducted, using FTIR, quantum cascade laser absorption spectroscopy (QCLAS), GC-FID and component-specific ozone and oxygen analysers to investigate recovery rates, conservation of isotopic signatures and spectral interferences after preconcentration. We achieve quantitative N2O recovery of >99% with only minor, statistically not significant isotopic fractionation and no relevant spectral interferences from other atmospheric constituents. The developed preconcentration unit also has the potential to be applied to other trace gases and their isotopic composition.

  1. Molar Heat Capacity (Cv) for Saturated and Compressed Liquid and Vapor Nitrogen from 65 to 300 K at Pressures to 35 MPa. (United States)

    Magee, J W


    Molar heat capacities at constant volume (Cv ,) for nitrogen have been measured with an automated adiabatic calorimeter. The temperatures ranged from 65 to 300 K, while pressures were as high as 35 MPa. Calorimetric data were obtained for a total of 276 state conditions on 14 isochores. Extensive results which were obtained in the saturated liquid region (Cv((2)) and Cσ ) demonstrate the internal consistency of the Cv (ρ,T) data and also show satisfactory agreement with published heat capacity data. The overall uncertainty of the Cv values ranges from 2% in the vapor to 0.5% in the liquid.

  2. Oligomerization of ethylene catalysed by nickel complexes associated with nitrogen ligands in ionic liquids; Oligomerisation de l'ethylene catalysee par des complexes du nickel associes a des ligands azotes dans les liquides ioniques

    Energy Technology Data Exchange (ETDEWEB)

    Lecocq, V.


    We report here the use of a new class of catalytic systems based on a nickel active center associated with nitrogen ligands, such as di-imines, or imino-pyridines, for the oligomerization of ethylene in a biphasic medium using ionic liquids as the catalyst solvent. The nickel catalyst is immobilized in the ionic liquid phase in which the olefinic reaction products are poorly miscible. This biphasic system makes possible an easy separation and recycle of the catalyst. Numerous di-imine and imino-pyridine ligands with different steric and electronic properties have been synthesized and their corresponding nickel complexes isolated and characterized. Different ionic liquids, based on chloro-aluminates or non-chloro-aluminates anions, have also been prepared and characterized. The effect of the nature of the ligand, the ionic liquid, the nickel precursor and its mode of activation have been studied and correlated with the selectivity and activity of the transformation of ethylene. (author)

  3. Two-phase flow characteristics of liquid nitrogen in vertically upward 0.5 and 1.0 mm micro-tubes: Visualization studies (United States)

    Zhang, P.; Fu, X.


    Application of liquid nitrogen to cooling is widely employed in many fields, such as cooling of the high temperature superconducting devices, cryosurgery and so on, in which liquid nitrogen is generally forced to flow inside very small passages to maintain good thermal performance and stability. In order to have a full understanding of the flow and heat transfer characteristics of liquid nitrogen in micro-tube, high-speed digital photography was employed to acquire the typical two-phase flow patterns of liquid nitrogen in vertically upward micro-tubes of 0.531 and 1.042 mm inner diameters. It was found from the experimental results that the flow patterns were mainly bubbly flow, slug flow, churn flow and annular flow. And the confined bubble flow, mist flow, bubble condensation and flow oscillation were also observed. These flow patterns were characterized in different types of flow regime maps. The surface tension force and the size of the diameter were revealed to be the major factors affecting the flow pattern transitions. It was found that the transition boundaries of the slug/churn flow and churn/annular flow of the present experiment shifted to lower superficial vapor velocity; while the transition boundary of the bubbly/slug flow shifted to higher superficial vapor velocity compared to the results of the room-temperature fluids in the tubes with the similar hydraulic diameters. The corresponding transition boundaries moved to lower superficial velocity when reducing the inner diameter of the micro-tubes. Time-averaged void fraction and heat transfer characteristics for individual flow patterns were presented and special attention was paid to the effect of the diameter on the variation of void fraction.

  4. Long-term storage of peripheral blood stem cells frozen and stored with a conventional liquid nitrogen technique compared with cells frozen and stored in a mechanical freezer. (United States)

    McCullough, Jeffrey; Haley, Rebecca; Clay, Mary; Hubel, Allison; Lindgren, Bruce; Moroff, Gary


    Cryopreservation of hematopoietic progenitor cells using liquid nitrogen and controlled-rate freezing requires complex equipment and highly trained staff and is expensive. We compared the liquid nitrogen method with methods using a combination of dimethyl sulfoxide (DMSO) and hydroxyethyl starch (HES) for cryopreservation followed by storage in mechanical freezers. Peripheral blood stem cells (PBSCs) were collected from normal donors by apheresis and allocated to one of four preservation and storage conditions: 1) 10% DMSO with freezing in liquid nitrogen and storage in liquid nitrogen, 2) 5% DMSO and 6% HES with freezing and storage in a -80 degrees C mechanical freezer, 3) 5% DMSO and 6% HES with freezing in a -80 degrees C mechanical freezer and storage in a -135 degrees C mechanical freezer, or 4) 5% DMSO and 6% HES with freezing and storage both in a 135 degrees C mechanical freezer. Cells were stored for 5 years during which total nucleated cells (TNCs), cell viability, CD34+ cell content, and colony-forming unit-granulocyte-macrophage content were determined. There were some significant differences in the variables measured during freezing and the 5 years of storage compared to the values before freezing and storage; however, these differences were not consistent and do not favor one protocol over the others. Samples stored for 24 hours before cryopreservation showed a significant decrease in TNCs, but no other significant changes during the 5 years. In vitro measurements indicate that PBSCs can be successfully frozen and stored using a combination of DMSO and HES providing smaller amounts of DMSO and allowing simplified freezing and storage conditions.

  5. Analysis and Measurement of Bubble Dynamics and Associated Flow Field in Subcooled Nucleate Boiling Flows

    Energy Technology Data Exchange (ETDEWEB)

    Barclay G. Jones


    In recent years, subooled nucleate boiling (SNB) has attrcted expanding research interest owing to the emergence of axial offset anomaly (AOA) or crud-induced power shigt (CIPS) in many operating US PWRs, which is an unexpected deviation in the core axial power distribution from the predicted power curves. Research indicates that the formation of the crud, which directly leads to AOA phenomena, results from the presence of the subcooled nucleate boiling, and is especially realted to bubble motion occurring in the core region.

  6. Predictions of the marviken subcooled critical mass flux using the critical flow scaling parameters

    Energy Technology Data Exchange (ETDEWEB)

    Park, Choon Kyung; Chun, Se Young; Cho, Seok; Yang, Sun Ku; Chung, Moon Ki [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    A total of 386 critical flow data points from 19 runs of 27 runs in the Marviken Test were selected and compared with the predictions by the correlations based on the critical flow scaling parameters. The results show that the critical mass flux in the very large diameter pipe can be also characterized by two scaling parameters such as discharge coefficient and dimensionless subcooling (C{sub d,ref} and {Delta}{Tau}{sup *} {sub sub}). The agreement between the measured data and the predictions are excellent. 8 refs., 8 figs. 1 tab. (Author)

  7. Cryotherapy with liquid nitrogen versus topical salicylic acid application for cutaneous warts in primary care: randomized controlled trial (United States)

    Bruggink, Sjoerd C.; Gussekloo, Jacobijn; Berger, Marjolein Y.; Zaaijer, Krista; Assendelft, Willem J.J.; de Waal, Margot W.M.; Bavinck, Jan Nico Bouwes; Koes, Bart W.; Eekhof, Just A.H.


    Background Cryotherapy is widely used for the treatment of cutaneous warts in primary care. However, evidence favours salicylic acid application. We compared the effectiveness of these treatments as well as a wait-and-see approach. Methods Consecutive patients with new cutaneous warts were recruited in 30 primary care practices in the Netherlands between May 1, 2006, and Jan. 26, 2007. We randomly allocated eligible patients to one of three groups: cryotherapy with liquid nitrogen every two weeks, self-application of salicylic acid daily or a wait-and-see approach. The primary outcome was the proportion of participants whose warts were all cured at 13 weeks. Analysis was on an intention-to-treat basis. Secondary outcomes included treatment adherence, side effects and treatment satisfaction. Research nurses assessed outcomes during home visits at 4, 13 and 26 weeks. Results Of the 250 participants (age 4 to 79 years), 240 were included in the analysis at 13 weeks (loss to follow-up 4%). Cure rates were 39% (95% confidence interval [CI] 29%–51%) in the cryotherapy group, 24% (95% CI 16%–35%) in the salicylic acid group and 16% (95% CI 9.5%–25%) in the wait-and-see group. Differences in effectiveness were most pronounced among participants with common warts (n = 116): cure rates were 49% (95% CI 34%–64%) in the cryotherapy group, 15% (95% CI 7%–30%) in the salicylic acid group and 8% (95% CI 3%–21%) in the wait-and-see group. Cure rates among the participants with plantar warts (n = 124) did not differ significantly between treatment groups. Interpretation For common warts, cryotherapy was the most effective therapy in primary care. For plantar warts, we found no clinically relevant difference in effectiveness between cryotherapy, topical application of salicylic acid or a wait-and-see approach after 13 weeks. ( registration no. ISRCTN42730629) PMID:20837684

  8. Fertilizer performance of liquid fraction of digestate as synthetic nitrogen substitute in silage maize cultivation for three consecutive years. (United States)

    Sigurnjak, I; Vaneeckhaute, C; Michels, E; Ryckaert, B; Ghekiere, G; Tack, F M G; Meers, E


    Following changes over recent years in fertilizer legislative framework throughout Europe, phosphorus (P) is taking over the role of being the limiting factor in fertilizer application rate of animal manure. This results in less placement area for spreading animal manure. As a consequence, more expensive and energy demanding synthetic fertilizers are required to meet crop nutrient requirements despite existing manure surpluses. Anaerobic digestion followed by mechanical separation of raw digestate, results in liquid fraction (LF) of digestate, a product poor in P but rich in nitrogen (N) and potassium (K). A 3-year field experiment was conducted to evaluate the impact of using the LF of digestate as a (partial) substitute for synthetic N fertilizer. Two different fertilization strategies, the LF of digestate in combination with respectively animal manure and digestate, were compared to the conventional fertilization regime of raw animal manure with synthetic fertilizers. Results from the 3-year trial indicate that the LF of digestate may substitute synthetic N fertilizers without crop yield losses. Through fertilizer use efficiency assessment it was observed that under-fertilization of soils with a high P status could reduce P availability and consequently the potential for P leaching. Under conditions of lower K application, more sodium was taken up by the crop. In arid regions, this effect might reduce the potential risk of salt accumulation that is associated with organic fertilizer application. Finally, economic and ecological benefits were found to be higher when LF of digestate was used as a synthetic N substitute. Future perspectives indicate that nutrient variability in bio-based fertilizers will be one of the greatest challenges to address in the future utilization of these products. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. [Development of a liquid fermentation system and encystment for a nitrogen-fixing bacterium strain having biofertilizer potential]. (United States)

    Camelo-Rusinque, Mauricio; Moreno-Galván, Andrés; Romero-Perdomo, Felipe; Bonilla-Buitrago, Ruth

    The indiscriminate use of chemical fertilizers has contributed to the deterioration of the biological, physical and chemical properties of the soil, resulting in the loss of its productive capacity. For this reason, the use of biofertilizers has emerged as a technological alternative. The objective of this research was to develop a suitable liquid fermentation system and encystment for the multiplication of Azotobacter chroococcum AC1 strain, a bacterium employed in a biofertilizer formulation produced at present by CARPOICA, Colombia. Sequential statistical designs were used to determine the conditions in the fermentation system. The interaction between agitation, aeration and pH was evaluated on the viable biomass (CFU/ml) of AC1. In addition, the encystment ability of the strain was evaluated using two encystment agents and the potential plant growth-promoting rhizobacteria (PGPR) activity was assessed by different techniques, such as nitrogen fixation by ARA, phosphate solubilization by the phospho-molybdenum-blue reaction and indolic compound production by colorimetric reaction using the Salkowski reagent. Results showed significant effects (p<0.05) on the viable biomass in the three conditions (pH, aeration and agitation) tested individually, in one dual interaction and one tripartite interaction, were demonstrated to have a positive effect on the response variable aeration and agitation. The addition of the two encystment agents evaluated, AE01 and AE02, demonstrated the ability of AC1 to form cysts under stress conditions. Likewise, fermentation and encystment conditions did not affect the biological activities tested. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Experimental study of an upward sub-cooled forced convection in a rectangular channel (United States)

    Kouidri, A.; Madani, B.; Roubi, B.; Hamadouche, A.


    The upward sub-cooled forced convection in a rectangular channel is investigated experimentally. The aim of the present work is the studying of the local heat transfer phenomena. Concerning the experimentation: the n-pentane is used as a working fluid, the independent variables are: the velocity in the range from 0.04 to 0.086 m/s and heat flux density with values between 1.8 and 7.36 W/cm2. The results show that the local Nusselt number distribution is not uniform along the channel; however, uniformity is observed in the mean Nusselt number for Reynolds under 1600. On the other hand, a new correlation to predict the local fluid temperature is established as a function of local wall temperature. The wall's heat is dissipated under the common effect of the sub-cooled regime; therefore, the local heat transfer coefficient is increased. The study of the thermal equilibrium showed that for Reynolds less than 1500; almost all of the heat flux generated by the heater cartridges is absorbed by the fluid.

  11. A sensitivity analysis of the mass balance equation terms in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Braz Filho, Francisco A.; Caldeira, Alexandre D.; Borges, Eduardo M., E-mail:, E-mail:, E-mail: [Instituto de Estudos Avancados (IEAv), Sao Jose dos Campos, SP (Brazil). Div. de Energia Nuclear


    In a heated vertical channel, the subcooled flow boiling occurs when the fluid temperature reaches the saturation point, actually a small overheating, near the channel wall while the bulk fluid temperature is below this point. In this case, vapor bubbles are generated along the channel resulting in a significant increase in the heat flux between the wall and the fluid. This study is particularly important to the thermal-hydraulics analysis of Pressurized Water Reactors (PWRs). The computational fluid dynamics software FLUENT uses the Eulerian multiphase model to analyze the subcooled flow boiling. In a previous paper, the comparison of the FLUENT results with experimental data for the void fraction presented a good agreement, both at the beginning of boiling as in nucleate boiling at the end of the channel. In the region between these two points the comparison with experimental data was not so good. Thus, a sensitivity analysis of the mass balance equation terms, steam production and condensation, was performed. Factors applied to the terms mentioned above can improve the agreement of the FLUENT results to the experimental data. Void fraction calculations show satisfactory results in relation to the experimental data in pressures values of 15, 30 and 45 bars. (author)

  12. Catalytic upgrading nitrogen-riched wood syngas to liquid hydrocarbon mixture over Fe-Pd/ZSM-5 catalyst (United States)

    Qiangu Yan; Fei Yu; Zhiyong Cai; Jilei Zhang


    Biomass like wood chips, switchgrass and other plant residues are first converted to syngas through gasification process using air, oxygen or steam. A downdraft gasifier is performed for syngas production in Mississippi State. The syngas from the gasifier contains up to 49% (vol) N2. High-level nitrogen-containing (nitrogen can be up to 60%)...

  13. Performance Assessment of 239 Series Sub-cooling Heat Exchangers for the Large Hadron Collider

    CERN Document Server

    Riddone, G; Roussel, P; Moracchioli, R; Tavian, L


    Helium sub-cooling heat exchangers of the counter-flow type are used to minimize the vapor fraction produced in the final expansion of the 1.9 K distributed cooling loops used for cooling the superconducting magnets of the Large Hadron Collider (LHC). These components are of compact design, featuring low-pressure drop and handling very low pressure vapor at low temperature. Following a qualification phase of prototypes, a contract has been placed in European industry for the supply of 239 heat exchanger units. Different levels of extracted heat load require three different variants of heat exchangers. This paper will describe the manufacturing phase with emphasis on the main difficulties encountered to keep the production quality after a brief recall of the prototype phase. Finally, the acceptance tests performed at room temperature and at the nominal cryogenic condition at the factory and at CEA-Grenoble will be presented.

  14. Modernization of NASA's Johnson Space Center Chamber: A Liquid Nitrogen System to Support Cryogenic Vacuum Optical Testing of the James Webb Space Telescope (JWST) (United States)

    Garcia, Sammy; Homan, Jonathan; Montz, Michael


    NASA is the mission lead for the James Webb Space Telescope (JWST), the next of the “Great Observatories”, scheduled for launch in 2018. It is directly responsible for the integration and test (I&T) program that will culminate in an end-to-end cryo vacuum optical test of the flight telescope and instrument module in Chamber A at NASA Johnson Space Center. Historic Chamber A is the largest thermal vacuum chamber at Johnson Space Center and one of the largest space simulation chambers in the world. Chamber A has undergone a major modernization effort to support the deep cryogenic, vacuum and cleanliness requirements for testing the JWST. This paper describes the steps performed in efforts to convert the existing the 60’s era Liquid Nitrogen System from a forced flow (pumped) process to a natural circulation (thermo-siphon) process. In addition, the paper will describe the dramatic conservation of liquid nitrogen to support the long duration thermal vacuum testing. Lastly, describe the simplistic and effective control system which results in zero to minimal human inputs during steady state conditions.

  15. Optimization of multi response in end milling process of ASSAB XW-42 tool steel with liquid nitrogen cooling using Taguchi-grey relational analysis (United States)

    Norcahyo, Rachmadi; Soepangkat, Bobby O. P.


    A research was conducted for the optimization of the end milling process of ASSAB XW-42 tool steel with multiple performance characteristics based on the orthogonal array with Taguchi-grey relational analysis method. Liquid nitrogen was applied as a coolant. The experimental studies were conducted under varying the liquid nitrogen cooling flow rates (FL), and the end milling process variables, i.e., cutting speed (Vc), feeding speed (Vf), and axial depth of cut (Aa). The optimized multiple performance characteristics were surface roughness (SR), flank wear (VB), and material removal rate (MRR). An orthogonal array, signal-to-noise (S/N) ratio, grey relational analysis, grey relational grade, and analysis of variance were employed to study the multiple performance characteristics. Experimental results showed that flow rate gave the highest contribution for reducing the total variation of the multiple responses, followed by cutting speed, feeding speed, and axial depth of cut. The minimum surface roughness, flank wear, and maximum material removal rate could be obtained by using the values of flow rate, cutting speed, feeding speed, and axial depth of cut of 0.5 l/minute, 109.9 m/minute, 440 mm/minute, and 0.9 mm, respectively.

  16. Direct dark matter detection and neutrinoless double beta decay with an array of 40 kg of `naked' natural Ge and 11 kg of enriched 76Ge detectors in liquid nitrogen (United States)

    Baudis, L.; Dietz, A.; Heusser, G.; Majorovits, B.; Strecker, H.; Klapdor-Kleingrothaus, H. V.


    Detection of the recoil energy deposited by a weakly interacting massive particle (WIMP) scattering off a nucleus or of the neutrinoless double beta decay signature in a `naked' (natural or enriched) Ge crystal immersed in liquid nitrogen provides a new, yet simple implementation of a well know technology to the fields of direct dark matter and double beta decay searches. We show that an array with a total mass of 40 kg of natural Ge and 11 kg of enriched 76Ge detectors operated in liquid nitrogen in a compact setup could yield important physics results by directly looking for a WIMP signature and testing the Majorana neutrino mass down to 0.1 eV. The method could be easily extended to much larger masses and, by increasing the amount of liquid nitrogen surrounding the detectors, to much lower backgrounds.

  17. CO2 with Mechanical Subcooling vs. CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration Applications Thermodynamic Analysis

    Directory of Open Access Journals (Sweden)

    Laura Nebot-Andrés


    Full Text Available A recent trend to spread the use of CO2 refrigeration cycles in warm regions of the world is to combine a CO2 cycle with another one using a high performance refrigerant. Two alternatives are being considered: cascade and mechanical subcooling systems. Both respond to a similar configuration of the refrigeration cycle, they being based on the use of two compressors and same number of heat exchangers. However, the compressor, heat exchanger sizes and energy performance differ a lot between them. This work, using experimental relations for CO2 and R1234yf semi-hermetic compressors analyzes in depth both alternatives under the warm climate of Spain. In general, it was concluded that the CO2 refrigeration solution with mechanical subcooling would cover all the conditions with high overall energy efficiency, thus it being recommended for further extension of the CO2 refrigeration applications.

  18. Effects of solid-liquid separation on recovering residual methane and nitrogen from digested dairy cow manure

    DEFF Research Database (Denmark)

    Kaparaju, Prasad Laxmi-Narasimha; Rintala, J.A.


    The feasibility of optimizing methane and nitrogen recovery of samples obtained from farm biogas digester (35 degrees C) and post-storage tank (where digested material is stored for 9-12 months) was studied by separating the materials into different fractions using 2, 1, 0.5 and 0.25 mm sieves. M...

  19. Nitrogen recovery from liquid manure using gas-permeable membranes: Effect of wastewater strength and pH control (United States)

    The costs of fertilizers have rapidly increased in recent years, especially nitrogen (N) fertilizer such as anhydrous ammonia which is made from natural gas. Thus, new treatment technologies for abatement of ammonia emissions in livestock operations are being focused on N recovery in addition to the...

  20. Evolution of steam-water flow structure under subcooled water boiling at smooth and structured heating surfaces (United States)

    Vasiliev, N. V.; Zeigarnik, Yu A.; Khodakov, K. A.


    Experimentally studying of subcooled water boiling in rectangular channel electrically heated from one side was conducted. Flat surfaces, both smooth and coated by microarc oxidation technology, were used as heating surfaces. The tests were conducted at atmospheric pressure in the range of mass flow rate from 650 to 1300 kg/(m2 s) and water subcooling relative to saturation temperature from 23 to 75 °C. Using high-speed filming a change in the two-phase flow structure and its statistic characteristics (nucleation sites density, vapor bubble distribution by size, etc.) were studied. With an increase in the heat flux density (with the mass flow rate and subcooling being the same) and amount and size of the vapor bubbles increased also. At a relatively high heat flux density, non-spherical vapor agglomerates appeared at the heating surface as a result of coalescence of small bubbles. They originated in chaotic manner in arbitrary points of the heating surface and then after random evolution in form and size collapsed. The agglomerate size reached several millimeters and their duration of life was several milliseconds. After formation of large vapor agglomerates, with a further small increase in heat flux density a burnout of the heating surface occurred. In most cases the same effect took place if the large agglomerates were retained for several minutes.

  1. Numerical simulation in a subcooled water flow boiling for one-sided high heat flux in reactor divertor

    Energy Technology Data Exchange (ETDEWEB)

    Liu, P., E-mail: [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); School of Mechanical Engineering, Anhui University of Science and Technology, Huainan 232001 (China); Peng, X.B., E-mail: [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Song, Y.T. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Fang, X.D. [Institute of Air Conditioning and Refrigeration, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Huang, S.H. [University of Science and Technology of China, Hefei 230026 (China); Mao, X. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)


    Highlights: • The Eulerian multiphase models coupled with Non-equilibrium Boiling model can effectively simulate the subcooled water flow boiling. • ONB and FDB appear earlier and earlier with the increase of heat fluxes. • The void fraction increases gradually along the flow direction. • The inner CuCrZr tube deteriorates earlier than the outer tungsten layer and the middle OFHC copper layer. - Abstract: In order to remove high heat fluxes for plasma facing components in International Thermonuclear Experimental Reactor (ITER) divertor, a numerical simulation of subcooled water flow boiling heat transfer in a vertically upward smooth tube was conducted in this paper on the condition of one-sided high heat fluxes. The Eulerian multiphase model coupled with Non-equilibrium Boiling model was adopted in numerical simulation of the subcooled boiling two-phase flow. The heat transfer regions, thermodynamic vapor quality (x{sub th}), void fraction and temperatures of three components on the condition of the different heat fluxes were analyzed. Numerical results indicate that the onset of nucleate boiling (ONB) and fully developed boiling (FDB) appear earlier and earlier with increasing heat flux. With the increase of heat fluxes, the inner CuCrZr tube will deteriorate earlier than the outer tungsten layer and the middle oxygen-free high-conductivity (OFHC) copper layer. These results provide a valuable reference for the thermal-hydraulic design of a water-cooled W/Cu divertor.

  2. CFD analysis of bubble microlayer and growth in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Owoeye, Eyitayo James, E-mail:; Schubring, DuWanye, E-mail:


    Highlights: • A new LES-microlayer model is introduced. • Analogous to the unresolved SGS in LES, analysis of bubble microlayer was performed. • The thickness of bubble microlayer was computed at both steady and transient states. • The macroscale two-phase behavior was captured with VOF coupled with AMR. • Numerical validations were performed for both the micro- and macro-region analyses. - Abstract: A numerical study of single bubble growth in turbulent subcooled flow boiling was carried out. The macro- and micro-regions of the bubble were analyzed by introducing a LES-microlayer model. Analogous to the unresolved sub-grid scale (SGS) in LES, a microlayer analysis was performed to capture the unresolved thermal scales for the micro-region heat transfer by deriving equations for the microlayer thickness at steady and transient states. The phase change at the macro-region was based on Volume-of-Fluid (VOF) interface tracking method coupled with adaptive mesh refinement (AMR). Large Eddy Simulation (LES) was used to model the turbulence characteristics. The numerical model was validated with multiple experimental data from the open literature. This study includes parametric variations that cover the operating conditions of boiling water reactor (BWR) and pressurized water reactor (PWR). The numerical model was used to study the microlayer thickness, growth rate, dynamics, and distortion of the bubble.

  3. Analysis of experimental routines of high enthalpy steam discharge in subcooled water

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Rafael R., E-mail: [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil); Andrade, Delvonei A., E-mail: [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)


    The discharge of high enthalpy steam through safety release valves out from pressurizers in PWR's needs to be condensed in order to allow the treatment of possibly present radwaste within. The Direct Contact Condensation is used in a relief tank to achieve the condensation. Care must be taken to avoid the bypass of the steam through the subcooled water, what would increase the peak of pressure and the necessity of structural reinforcement of the relief tank. An experiment to determine the optimal set up of the relief tank components and their characteristics (type of sprinkler, level of water, volume of tank, discharge direction, pressure in the pressurizer among others) was executed in 2000, in the CTE 150 facility, in CTMSP. In a total, 144 routines varying its components and characteristics were made, although no comprehensive analysis of its results were yet made, since the mass of data was too big to be readily analyzed. In order to comprehensively analyze it, a VBA program is being made to compile and graphically represent the mass of data. The current state of this program allowed conclusions over the peak pressure, adiabatic assumption of the experiment, and the quality of the steam generated due to the discharge. (author)

  4. Analysis of Screen Channel LAD Bubble Point Tests in Liquid Methane at Elevated Temperature (United States)

    Hartwig, Jason; McQuillen, John


    This paper examines the effect of varying the liquid temperature and pressure on the bubble point pressure for screen channel Liquid Acquisition Devices in cryogenic liquid methane using gaseous helium across a wide range of elevated pressures and temperatures. Testing of a 325 x 2300 Dutch Twill screen sample was conducted in the Cryogenic Components Lab 7 facility at the NASA Glenn Research Center in Cleveland, Ohio. Test conditions ranged from 105 to 160K and 0.0965 - 1.78 MPa. Bubble point is shown to be a strong function of the liquid temperature and a weak function of the amount of subcooling at the LAD screen. The model predicts well for saturated liquid but under predicts the subcooled data.

  5. A biobased nitrogen-containing lubricant additive synthesized from expoxidized methyl oleate using an ionic liquid catalyst (United States)

    Utilizing an epoxidation route, an aniline adduct was synthesized from methyl oleate. An ionic liquid, 1-methylimidazolium tetrafluoroborate, was found to be the key for this catalytic system. The reaction produces a product with the aniline incorporated into the fatty chain, at the 9(10) position, ...

  6. Resistive sensing of gaseous nitrogen dioxide using a dispersion of single-walled carbon nanotubes in an ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Prabhash [Solidstate Electronics Research Laboratory (SERL), Faculty of Engineering and Technology, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 (India); Department of Nanoengineering, Samara State Aerospace University, 443086 Samara (Russian Federation); Pavelyev, V.S. [Department of Nanoengineering, Samara State Aerospace University, 443086 Samara (Russian Federation); Patel, Rajan [Center for Interdisciplinary Research in Basic Sciences (CIRBSc), Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 (India); Islam, S.S., E-mail: [Solidstate Electronics Research Laboratory (SERL), Faculty of Engineering and Technology, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025 (India)


    Graphical abstract: Ionic liquid ([C6-mim]PF6) used as dispersant agent for SWCNTs: An investigations were carried out to find the structural quality and surface modification for sensor application. - Highlights: • An effective technique based on Ionic liquids (IL) and their use as a dispersant. • Electron microscopy and spectroscopy for structure characterization. • Covalent linkage of ILs with SWNTs and dispersion of SWCNTs. • The IL-wrapped sensing film, capable for detecting trace levels of gas. - Abstract: Single-walled carbon nanotubes (SWCNTs) were dispersed in an imidazolium-based ionic liquid (IL) and investigated in terms of structural quality, surface functionalization and inter-CNT force. Analysis by field emission electron microscopy and transmission electron microscopy shows the IL layer to coat the SWNTs, and FTIR and Raman spectroscopy confirm strong binding of the ILs to the SWNTs. Two kinds of resistive sensors were fabricated, one by drop casting of IL-wrapped SWCNTs, the other by conventional dispersion of SWCNTs. Good response and recovery to NO{sub 2} is achieved with the IL-wrapped SWCNTs material upon UV-light exposure, which is needed because decrease the desorption energy barrier to increase the gas molecule desorption. NO{sub 2} can be detected in the 1–20 ppm concentration range. The sensor is not interfered by humidity due to the hydrophobic tail of PF6 (ionic liquid) that makes our sensor highly resistant to moisture.

  7. Absolute-magnetic-field measurement using nanogranular in-gap magnetic sensor with second-harmonic and liquid-nitrogen-temperature operation (United States)

    Tsukada, Keiji; Yasugi, Takuya; Majima, Yatsuse; Sakai, Kenji; Kiwa, Toshihiko


    To detect the absolute magnetic field, such as the earth's magnetic field, a linear magnetic response, a zero point, and thermal stability are required. We thus propose an operating method and sensor probe consisting of a nanogranular in-gap magnetic sensor (GIGS), an operational amplifier integrated circuit, and a modulation coil. The sensor probe was operated in second-harmonic mode at a liquid-nitrogen (Liq. N2) temperature. When an AC magnetic field was applied to GIGS, the second-harmonic signal was generated and modulated by the outer magnetic field to be measured. After lock-in detection, the modulated output signal showed good linearity and a zero point. Moreover, higher sensitivity and low noise with low thermal fluctuation was obtained by the cooling at Liq. N2 temperature.

  8. Dynamic Mechanical Properties and Fracture Surface Morphologies of Core-Shell Rubber (CSR) Toughened Epoxy at Liquid Nitrogen (Ln2) Temperatures (United States)

    Wang, J.; Magee, D.; Schneider, J. A.


    The dynamic mechanical properties and fracture surface morphologies were evaluated for a commercial epoxy resin toughened with two types of core-shell rubber (CSR) toughening agents (Kane Ace(Registered TradeMark) MX130 and MX960). The impact resistance (R) was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The resulting fracture surface morphologies were examined using Scanning Electron Microscopy (SEM). Fractographic observations of the CSR toughened epoxy tested at ambient temperature, showed a fracture as characterized by slender dendrite textures with large voids. The increasing number of dendrites and decreasing size of scale-like texture with more CSR particles corresponded with increased R. As the temperature decreased to Liquid Nitrogen (LN 2), the fracture surfaces showed a fracture characterized by a rough, torn texture containing many river markings and deep furrows.

  9. Absolute-magnetic-field measurement using nanogranular in-gap magnetic sensor with second-harmonic and liquid-nitrogen-temperature operation

    Directory of Open Access Journals (Sweden)

    Keiji Tsukada


    Full Text Available To detect the absolute magnetic field, such as the earth’s magnetic field, a linear magnetic response, a zero point, and thermal stability are required. We thus propose an operating method and sensor probe consisting of a nanogranular in-gap magnetic sensor (GIGS, an operational amplifier integrated circuit, and a modulation coil. The sensor probe was operated in second-harmonic mode at a liquid-nitrogen (Liq. N2 temperature. When an AC magnetic field was applied to GIGS, the second-harmonic signal was generated and modulated by the outer magnetic field to be measured. After lock-in detection, the modulated output signal showed good linearity and a zero point. Moreover, higher sensitivity and low noise with low thermal fluctuation was obtained by the cooling at Liq. N2 temperature.

  10. Double Soft-Template Synthesis of Nitrogen/Sulfur-Codoped Hierarchically Porous Carbon Materials Derived from Protic Ionic Liquid for Supercapacitor. (United States)

    Sun, Li; Zhou, Hua; Li, Li; Yao, Ying; Qu, Haonan; Zhang, Chengli; Liu, Shanhu; Zhou, Yanmei


    Heteroatom-doped hierarchical porous carbon materials derived from the potential precursors and prepared by a facile, effective, and low-pollution strategy have recently been particularly concerned in different research fields. In this study, the interconnected nitrogen/sulfur-codoped hierarchically porous carbon materials have been successfully obtained via one-step carbonization of the self-assembly of [Phne][HSO4] (a protic ionic liquid originated from dilute sulfuric acid and phenothiazine by a straightforward acid-base neutralization) and the double soft-template of OP-10 and F-127. During carbonization process, OP-10 as macroporous template and F-127 as mesoporous template were removed, while [Phne][HSO4] not only could be used as carbon, nitrogen, and sulfur source, but also as a pore forming agent to create micropores. The acquired carbon materials for supercapacitor not only hold a large specific capacitance of 302 F g-1 even at 1.0 A g-1, but also fine rate property with 169 F g-1 at 10 A g-1 and excellent capacitance retention of nearly 100% over 5000 circulations in 6 M KOH electrolyte. Furthermore, carbon materials also present eximious rate performance with 70% in 1 M Na2SO4 electrolyte.

  11. Biodegradation of Alachlor in Liquid and Soil Cultures Under Variable Carbon and Nitrogen Sources by Bacterial Consortium Isolated from Corn Field Soil

    Directory of Open Access Journals (Sweden)

    Simin Nasseri


    Full Text Available Alachlor, an aniline herbicide widely used in corn production, is frequently detected in water resources. The main objectives of this research were focused on isolating bacterial consortium capable of alachlor biodegradation, assessing the effects of carbon and nitrogen sources on alachlor biodegradation and evaluating the feasibility of using bacterial consortium in soil culture. Kavar corn field soil with a long history of alachlor application in Fars province of Iran has been explored for their potential of alachlor biodegradation. The influence of different carbon compounds (glucose, sodium citrate, sucrose, starch and the combination of these compounds, the effect of nitrogen sources (ammonium nitrate and urea and different pH (5.5-8.5 on alachlor removal efficiency by the bacterial consortium in liquid culture were investigated. After a multi-step enrichment program 100 days of acclimation, a culture with the high capability of alachlor degradation was obtained (63%. Glucose and sodium citrate had the highest alachlor reduction rate (85%. Alachlor reduction rate increased more rapidly by the addition of ammonium nitrate (94% compare to urea. Based on the data obtained in the present study, pH of 7.5 is optimal for alachlor biodegradation. After 30 days of incubation, the percent of alachlor reduction were significantly enhanced in the inoculated soils (74% as compared to uninoculated control soils (17.67% at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with bacterial consortium may enhance the rate of alachlor degradation in a polluted soil.

  12. Low Temperature Selective Catalytic Reduction of Nitrogen Oxides in Production of Nitric Acid by the Use of Liquid

    Directory of Open Access Journals (Sweden)

    Kabljanac, Ž.


    Full Text Available This paper presents the application of low-temperature selective catalytic reduction of nitrous oxides in the tail gas of the dual-pressure process of nitric acid production. The process of selective catalytic reduction is carried out using the TiO2/WO3 heterogeneous catalyst applied on a ceramic honeycomb structure with a high geometric surface area per volume. The process design parameters for nitric acid production by the dual-pressure procedure in a capacity range from 75 to 100 % in comparison with designed capacity for one production line is shown in the Table 1. Shown is the effectiveness of selective catalytic reduction in the temperature range of the tail gas from 180 to 230 °C with direct application of liquid ammonia, without prior evaporation to gaseous state. The results of inlet and outlet concentrations of nitrous oxides in the tail gas of the nitric acid production process are shown in Figures 1 and 2. Figure 3 shows the temperature dependence of the selective catalytic reduction of nitrous oxides expressed as NO2in the tail gas of nitric acid production with the application of a constant mass flow of liquid ammonia of 13,0 kg h-1 and average inlet mass concentration of the nitrous oxides expressed as NO2of 800,0 mgm-3 during 100 % production capacity. The specially designed liquid-ammonia direct-dosing system along with the effective homogenization of the tail gas resulted in emission levels of nitrous oxides expressed as NO2 in tail gas ranging from 100,0 to 185,0 mg m-3. The applied low-temperature selective catalytic reduction of the nitrous oxides in the tail gases by direct use of liquid ammonia is shown in Figure 4. It is shown that low-temperature selective catalytic reduction with direct application of liquid ammonia opens a new opportunity in the reduction of nitrous oxide emissions during nitric acid production without the risk of dangerous ammonium nitrate occurring in the process of subsequent energy utilization of

  13. ASRDI oxygen technology survey. Volume 5: Density and liquid level measurement instrumentation for the cryogenic fluids oxygen, hydrogen, and nitrogen (United States)

    Roder, H. M.


    Information is presented on instrumentation for density measurement, liquid level measurement, quantity gauging, and phase measurement. Coverage of existing information directly concerned with oxygen was given primary emphasis. A description of the physical principle of measurement for each instrumentation type is included. The basic materials of construction are listed if available from the source document for each instrument discussed. Cleaning requirements, procedures, and verification techniques are included.

  14. Experimental study on forced convective and subcooled flow boiling heat transfer coefficient of water-ethanol mixtures: an application in cooling of heat dissipative devices (United States)

    Suhas, B. G.; Sathyabhama, A.


    The experimental study is carried out to determine forced convective and subcooled flow boiling heat transfer coefficient in conventional rectangular channels. The fluid is passed through rectangular channels of 0.01 m depth, 0.01 m width, and 0.15 m length. The parameters varied are heat flux, mass flux, inlet temperature and volume fraction of ethanol. Forced convective heat transfer coefficient increases with increase in heat flux and mass flux, but effect of mass flux is less significant. Subcooled flow boiling heat transfer increases with increase in heat flux and mass flux, but the effect of heat flux is dominant. During the subcooled flow boiling region, the effect of mass flux will not influence the heat transfer. The strong Marangoni effect will increase the heat transfer coeffient for mixture with 25% ethanol volume fraction. The results obtained for subcooled flow boiling heat transfer coefficient of water are compared with available literature correlations. It is found that Liu-Winterton equation predicts the experimental results better when compared with that of other literature correlations. An empirical correlation for subcooled flow boiling heat transfer coefficient as a function of mixture wall super heat, mass flux, volume fractions and inlet temperature is developed from the experimental results.

  15. Experimental study on forced convective and subcooled flow boiling heat transfer coefficient of water-ethanol mixtures: an application in cooling of heat dissipative devices (United States)

    Suhas, B. G.; Sathyabhama, A.


    The experimental study is carried out to determine forced convective and subcooled flow boiling heat transfer coefficient in conventional rectangular channels. The fluid is passed through rectangular channels of 0.01 m depth, 0.01 m width, and 0.15 m length. The parameters varied are heat flux, mass flux, inlet temperature and volume fraction of ethanol. Forced convective heat transfer coefficient increases with increase in heat flux and mass flux, but effect of mass flux is less significant. Subcooled flow boiling heat transfer increases with increase in heat flux and mass flux, but the effect of heat flux is dominant. During the subcooled flow boiling region, the effect of mass flux will not influence the heat transfer. The strong Marangoni effect will increase the heat transfer coeffient for mixture with 25% ethanol volume fraction. The results obtained for subcooled flow boiling heat transfer coefficient of water are compared with available literature correlations. It is found that Liu-Winterton equation predicts the experimental results better when compared with that of other literature correlations. An empirical correlation for subcooled flow boiling heat transfer coefficient as a function of mixture wall super heat, mass flux, volume fractions and inlet temperature is developed from the experimental results.

  16. Production and correlation of reactive oxygen and nitrogen species in gas- and liquid-phase generated by helium plasma jets under different pulse widths (United States)

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


    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.

  17. The Importance of Correct Modeling of Bubble Size and Condensation in Prediction of Sub-Cooled Boiling Flows

    Directory of Open Access Journals (Sweden)

    S. Lo


    Full Text Available This paper describes the updating of the sub-cooled boiling model used in CFD codes with the more recent and better sub-models. The improved sub-models include: Hibiki and Ishii [1] correlation for nucleation site density, Kocamustafaogullari [2] correlation for bubble departure diameter and the S-gamma model of Lo and Rao [3] for bubble size distribution in the flow. The new model has been tested against measured data from Debora [4] and Bartolomei [5]. The results show that improvement in the bubble size prediction has the most significant impact on the accuracy of the model.

  18. Numerical Study on Bubble Behaviour and Heat Transfer Characteristics of Subcooled Pool Boiling Based on Non-Empirical Boiling and Condensation Model

    Directory of Open Access Journals (Sweden)

    Y. Ose


    Full Text Available In this study, the transient three-dimensional numerical simulations based on the MARS (Multi-interface Advection and Reconstruction Solver with the non-empirical boiling and condensation model have been conducted for isolated boiling bubble behaviour in a subcooled pool. The effects of the wettability on the heating surface for the subcooled bubble departure behaviour were investigated. The numerical results showed in very good agreement with the experimental results. Furthermore, resulting from the wall heat flux evaluation, it was found that the wall heat flux near the contact line at the bottom of the bubble just before the bubble departing from the heating surface increases with increases of the degree of subcooling.

  19. Control of reactive oxygen and nitrogen species production in liquid by nonthermal plasma jet with controlled surrounding gas (United States)

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


    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.

  20. Validation and Calibration of Nuclear Thermal Hydraulics Multiscale Multiphysics Models - Subcooled Flow Boiling Study

    Energy Technology Data Exchange (ETDEWEB)

    Anh Bui; Nam Dinh; Brian Williams


    In addition to validation data plan, development of advanced techniques for calibration and validation of complex multiscale, multiphysics nuclear reactor simulation codes are a main objective of the CASL VUQ plan. Advanced modeling of LWR systems normally involves a range of physico-chemical models describing multiple interacting phenomena, such as thermal hydraulics, reactor physics, coolant chemistry, etc., which occur over a wide range of spatial and temporal scales. To a large extent, the accuracy of (and uncertainty in) overall model predictions is determined by the correctness of various sub-models, which are not conservation-laws based, but empirically derived from measurement data. Such sub-models normally require extensive calibration before the models can be applied to analysis of real reactor problems. This work demonstrates a case study of calibration of a common model of subcooled flow boiling, which is an important multiscale, multiphysics phenomenon in LWR thermal hydraulics. The calibration process is based on a new strategy of model-data integration, in which, all sub-models are simultaneously analyzed and calibrated using multiple sets of data of different types. Specifically, both data on large-scale distributions of void fraction and fluid temperature and data on small-scale physics of wall evaporation were simultaneously used in this work’s calibration. In a departure from traditional (or common-sense) practice of tuning/calibrating complex models, a modern calibration technique based on statistical modeling and Bayesian inference was employed, which allowed simultaneous calibration of multiple sub-models (and related parameters) using different datasets. Quality of data (relevancy, scalability, and uncertainty) could be taken into consideration in the calibration process. This work presents a step forward in the development and realization of the “CIPS Validation Data Plan” at the Consortium for Advanced Simulation of LWRs to enable

  1. How to store plant tissues in the absence of liquid nitrogen? Ethanol preserves the RNA integrity of Cannabis sativa stem tissues

    Directory of Open Access Journals (Sweden)

    Lauralie Mangeot-Peter


    Full Text Available The preservation of intact RNA is a limiting step when gene expression profiling is performed using field-collected plant material. The use of liquid nitrogen ensures the optimal preservation of RNA, however it is not always practical, especially if the plant material has to be sampled in remote locations. Ethanol is known to preserve DNA in plant tissues even after a long storage period and here its suitability to preserve the RNA of textile hemp cortical tissues was tested. Hemp (Cannabis sativa L. is an economically important fibre crop because it supplies cellulosic bast fibres used in different industrial sectors. In this study we demonstrate the suitability of ethanol for RNA preservation by analyzing tissues stored at 4 °C for 1, 2, 4 and 8 days. We show that in all the cases the extracted RNA is intact. We finally analyze hemp stem tissues stored in ethanol for 1 month and demonstrate the preservation of the tissue structure, particularly of bast fibres.

  2. Development of gas chromatography-flame ionization detection system with a single column and liquid nitrogen-free for measuring atmospheric C2-C12 hydrocarbons. (United States)

    Liu, Chengtang; Mu, Yujing; Zhang, Chenglong; Zhang, Zhibo; Zhang, Yuanyuan; Liu, Junfeng; Sheng, Jiujiang; Quan, Jiannong


    A liquid nitrogen-free GC-FID system equipped with a single column has been developed for measuring atmospheric C2-C12 hydrocarbons. The system is consisted of a cooling unit, a sampling unit and a separation unit. The cooling unit is used to meet the temperature needs of the sampling unit and the separation unit. The sampling unit includes a dehydration tube and an enrichment tube. No breakthrough of the hydrocarbons was detected when the temperature of the enrichment tube was kept at -90 °C and sampling volume was 400 mL. The separation unit is a small round oven attached on the cooling column. A single capillary column (OV-1, 30 m × 0.32 mm I.D.) was used to separate the hydrocarbons. An optimal program temperature (-60 ∼ 170 °C) of the oven was achieved to efficiently separate C2-C12 hydrocarbons. There were good linear correlations (R(2)=0.993-0.999) between the signals of the hydrocarbons and the enrichment amount of hydrocarbons, and the relative standard deviation (RSD) was less than 5%, and the method detection limits (MDLs) for the hydrocarbons were in the range of 0.02-0.10 ppbv for sampling volume of 400 mL. Field measurements were also conducted and more than 50 hydrocarbons from C2 to C12 were detected in Beijing city. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Characterization of extracellular polymeric substances (EPS) from periphyton using liquid chromatography-organic carbon detection-organic nitrogen detection (LC-OCD-OND). (United States)

    Stewart, Theodora J; Traber, Jacqueline; Kroll, Alexandra; Behra, Renata; Sigg, Laura


    A protocol was developed to extract, fractionate, and quantitatively analyze periphyton extracellular polymeric substances (EPS), which obtains both information on the molecular weight (M r) distribution and protein and polysaccharide content. The EPS were extracted from freshwater periphyton between July and December 2011. Organic carbon (OC) compounds from different EPS extracts were analyzed using liquid chromatography-organic carbon detection-organic nitrogen detection (LC-OCD-OND), and total protein and polysaccharide content were quantified. Four distinct OC fractions, on the basis of M r, were identified in all extracts, corresponding to high M r biopolymers (≥80-4 kDa), degradation products of humic substances (M r not available), low M r acids (10-0.7 kDa), and small amphiphilic/neutral compounds (3-0.5 kDa). Low C/N ratios (4.3 ± 0.8) were calculated for the biopolymer fractions, which represented 16-38 % of the measured dissolved organic carbon (DOC), indicating a significant presence of high M r proteins in the EPS. Protein and polysaccharide represented the two major components of EPS and, when combined, accounted for the measured DOC in extracts. Differences in specific OC fractions of EPS extracts over the course of the study could be quantified using this method. This study suggests that LC-OCD-OND is a new valuable tool in EPS characterization of periphyton.

  4. Effect of long-term preservation of basidiomycetes on perlite in liquid nitrogen on their growth, morphological, enzymatic and genetic characteristics. (United States)

    Homolka, Ladislav; Lisá, Ludmila; Eichlerová, Ivana; Valášková, Vendula; Baldrian, Petr


    The macro- and micro-morphological features, mycelial extension rate, enzymatic activities and possible genetic changes were studied in 30 selected strains of basidiomycetes after 10-year cryopreservation on perlite in liquid nitrogen (LN). Comparisons with the same strains preserved by serial transfers on nutrient media at 4°C were also conducted. Production of ligninolytic enzymes and hydrogen peroxide was studied by quantitative spectrophotometric methods, whereas semiquantitative API ZYM testing was used to compare the levels of a wide range of hydrolytic enzymes. Our results show that cryopreservation in LN did not cause morphological changes in any isolate. The vitality of all fungi was successfully preserved and none of the physiological features were lost, even though the extension rate and enzyme activity were slightly affected. Moreover, sequence analysis of eight strains did not detect any changes in their genetic features after cryopreservation. These findings suggest that the perlite-based freezing protocol is suitable for long-term preservation of large numbers of basidiomycetes. Copyright © 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  5. Efficacy of liquid feeds varying in concentration and composition of fat, nonprotein nitrogen, and nonfiber carbohydrates for lactating dairy cows. (United States)

    Firkins, J L; Oldick, B S; Pantoja, J; Reveneau, C; Gilligan, L E; Carver, L


    In trial 1, we evaluated the efficacy of a liquid feed (LF) containing cane molasses and corn steep liquor as carriers of suspended white grease (WG) without or with urea (U) or with soybean lipid (SL; a byproduct of soybean processing) compared with roasted soybeans plus tallow blended into respective concentrates in a 16-wk lactation study. The dry matter intake (DMI) and milk production for LF diets were either similar to or greater than respective controls, although SL decreased milk fat percentage. In trial 2, we compared LF without fat to LF plus WG or SL and also evaluated the dose response to increasing amount of LF + WG in a 16-wk lactation trial in which the LF products were added to respective total mixed rations. The DMI was increased and then decreased (quadratic response) with increasing LF + WG without a linear response. However, production of milk, protein, and fat increased linearly with corresponding quadratic responses, which we interpret to be a result of a limiting returns response from DMI and density of net energy for lactation. When LF plus SL was fed, milk fat percentage and yield decreased compared with the comparable amount of LF + WG. In a 12-wk lactation study (trial 3), we added 3.25 or 6.5% of the dry matter as LF (a different but generally similar product than the previous trials and without fat) to diets formulated to maintain comparable ruminal nonstructural carbohydrate digestibility by adding soybean hulls to decrease nonfiber carbohydrates (NFC) concentration; the 6.5% LF diet was without or with Rumensin (11.5 g/909 kg of dry matter). When 3.25% LF was added but NFC was decreased from 40 to 37%, cows increased DMI and production of milk fat. Adding Rumensin decreased DMI but maintained milk fat yield compared with its 6.25% LF control without Rumensin. In trials 1 and 3, apparent total tract nutrient digestibility was not affected by treatment. In conclusion, feeding LF at about 5% (trial 2, which contained WG, 1.6% added sugar

  6. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic


    Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

  7. Void Measurements in the Regions of Sub-Cooled and Low-Quality Boiling. Part 2. Higher Mass Velocities

    Energy Technology Data Exchange (ETDEWEB)

    Rouhani, S.Z.


    This report consists mostly of tables of experimental data obtained in void measurements. It is a continuation and the completing part of a previous report with the same title. The data are from the measurements in a vertical annular channel with 25 mm O.D. and 12 mm I.D. at a heated length of 1090 mm. These experiments covered pressures from 10 to 50 bars, mass velocities from 650 to 1450 kg/m -sec., heat fluxes from 60 to 120 W/cm{sup 2}, sub-coolings from 30 to 0 C, and steam qualities from 0 to 12 %. The tables include the inlet temperatures and measured wall super-heat.

  8. Void Measurements in the Regions of Sub-Cooled and Low-Quality Boiling. Part 1. Low Mass Velocities

    Energy Technology Data Exchange (ETDEWEB)

    Rouhani, S.Z.


    By the application of the ({gamma}, n) reaction to boiling heavy water, void volume fractions have been measured in a vertical annular channel with 25 mm O.D. and 12 mm I.D. at a heated length of 1090 mm. The experiments covered pressures from 10 to 50 bars, mass velocities from 50 to 1450 kg/m-sec, heat fluxes from 30 to 90 W/cm{sup 2}, sub coolings from 30 to 0 C, and steam qualities from 0 to 15 %. The results indicate noticeable effects of pressure, heat flux and even mass velocity upon the variations of void with subcooling and steam quality. A novel explanation of the mechanism of their effects has been found and proved by qualitative analysis.

  9. Wall Area of Influence and Growing Wall Heat Transfer due to Sliding Bubbles in Subcooled Boiling Flow

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Junsoo; Estrada-Perez, Carlos E.; Hassan, Yassin A.


    A variety of dynamical features of sliding bubbles and their impact on wall heat transfer were observed at subcooled flow boiling conditions in a vertical square test channel. Among the wide range of parameters observed, we particularly focus in this paper on (i) the sliding bubbles’ effect on wall heat transfer (supplemantry discussion to the authors’ previous work in Yoo et al. (2016a,b)) and (ii) the wall area influenced by sliding bubbles in subcooled boiling flow. At first, this study reveals that the degree of wall heat transfer improvement due to sliding bubbles depended less on the wall superheat condition as the mass flux increased. Also, the sliding bubble trajectory was found to be one of the critical factors in order to properly describe the wall heat transfer associated with sliding bubbles. In particular, the wall area influenced by sliding bubbles depended strongly on both sliding bubble trajectory and sliding bubble size; the sliding bubble trajectory was also observed to be closely related to the sliding bubble size. Importantly, these results indicate the limitation of current approach in CFD analyses especially for the wall area of bubble influence. In addition, the analyses on the temporal fraction of bubbles’ residence (FR) along the heated wall show that the sliding bubbles typically travel through narrow path with high frequency while the opposite was observed downstream. That is, both FR and sliding bubble trajectory depended substantially on the distance from nucleation site, which is expected to be similar for the quenching heat transfer mode induced by sliding bubbles.

  10. Generalization of experimental data on amplitude and frequency of oscillations induced by steam injection into a subcooled pool

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva, Walter; Li, Hua [Division of Nuclear Power Safety, Royal Institute of Technology (KTH), Roslagstullsbacken 21, SE-10691 Stockholm (Sweden); Puustinen, Markku [Nuclear Engineering, LUT School of Energy Systems, Lappeenranta University of Technology (LUT), FIN-53851 Lappeenranta (Finland); Kudinov, Pavel, E-mail: [Division of Nuclear Power Safety, Royal Institute of Technology (KTH), Roslagstullsbacken 21, SE-10691 Stockholm (Sweden)


    Highlights: • Available data on steam injection into subcooled pool is generalized. • Scaling approach is proposed on amplitude and frequency of chugging oscillations. • The scaled amplitude has a maximum at Froude number Fr ≈ 2.8. • The scaled frequency has a minimum at Fr ≈ 6. • Both amplitude and frequency has a strong dependence on pool bulk temperature. - Abstract: Steam venting and condensation into a subcooled pool of water through a blowdown pipe can undergo a phenomenon called chugging, which is an oscillation of the steam–water interface inside the blowdown pipe. The momentum that is generated by the oscillations is directly proportional to the oscillations’ amplitude and frequency, according to the synthetic jet theory. Higher momentum can enhance pool mixing and positively affect the pool's pressure suppression capacity by reducing thermal stratification. In this paper, we present a generalization of available experimental data on the amplitude and frequency of oscillations during chugging. We use experimental data obtained in different facilities at different scales to suggest a scaling approach for non-dimensional amplitude and frequency of the oscillations. We demonstrate that the Froude number Fr (which relates the inertial forces to gravitational forces) can be used as a scaling criterion in this case. The amplitude has maximum at Fr ≈ 2.8. There is also a strong dependence of the amplitude on temperature; the lower the bulk temperature is the higher the scaled amplitude. A known analytical theory can only capture the decreasing trend in amplitude for Fr > 2.8 and fails to capture the increasing trend and the temperature dependence. Similarly, there is a minimum of the non-dimensional frequency at Fr ≈ 6. A strong dependence on temperature is also observed for Fr > 6; the lower the bulk temperature is the higher the scaled frequency. The known analytical theory is able to capture qualitatively the general trend in

  11. Optimization of the freezing process for hematopoietic progenitor cells: effect of precooling, initial dimethyl sulfoxide concentration, freezing program, and storage in vapor-phase or liquid nitrogen on in vitro white blood cell quality. (United States)

    Dijkstra-Tiekstra, Margriet J; Setroikromo, Airies C; Kraan, Marcha; Gkoumassi, Effimia; de Wildt-Eggen, Janny


    Adding dimethyl sulfoxide (DMSO) to hematopoietic progenitor cells (HPCs) causes an exothermic reaction, potentially affecting their viability. The freezing method might also influence this. The aim was to investigate the effect of 1) precooling of DMSO and plasma (D/P) and white blood cell (WBC)-enriched product, 2) DMSO concentration of D/P, 3) freezing program, and 4) storage method on WBC quality. WBC-enriched product without CD34+ cells was used instead of HPCs. This was divided into six or eight portions. D/P (20 or 50%; precooled or room temperature [RT]) was added to the WBC-enriched product (precooled or RT), resulting in 10% DMSO, while monitoring temperature. The product was frozen using controlled-rate freezing ("fast-rate" or "slow-rate") and placed in vapor-phase or liquid nitrogen. After thawing, WBC recovery and viability were determined. Temperature increased most for precooled D/P to precooled WBC-enriched product, without influence of 20 or 50% D/P, but remained for all variations below 30°C. WBC recovery for both freezing programs was more than 95%. Recovery of WBC viability was higher for slow-rate freezing compared to fast-rate freezing (74% vs. 61%; p Effect of precooling D/P or WBC-enriched product and of storage in vapor-phase or liquid nitrogen was marginal. Based on these results, precooling is not necessary. Fifty percent D/P is preferred over 20% D/P. Slow-rate freezing is preferred over fast-rate freezing. For safety reasons storage in vapor-phase nitrogen is preferred over storage in liquid nitrogen. Additional testing using real HPCs might be necessary. © 2014 AABB.

  12. Nitrogen oxides

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T.; Horiike, E.; Murakami, M.; Hosoya, T.; Miyanishi, T.; Amamiya, S.


    This invention relates to the removal of nitrogen oxides with an aqueous alkaline solution. Waste gas was introduced to an absorbing tower at a flow rate of 0.7--1.0 m/s while sodium hydroxide solution was pumped to the top of the tower at 10--15 l/m/sup 3/ gas. The liquid was sprayed into the waste gas and the resulting gas was led to a second absorbing tower and then a decomposition tower where the remaining NO/sub x/ was removed by sodium sulfide solution or Na/sub 2/S and NaOH mixed solution. With two absorbing towers and one decomposition tower, NO/sub x/ concentration was reduced from 2500 ppM to as low as 36 ppM, or 99 percent removal. With three absorbing towers, the rate of removal was below 80 percent.

  13. The Effect of Percentage of Nitrogen in Plasma Gas on Nitrogen ...

    African Journals Online (AJOL)

    The effect of percentage of nitrogen in plasma gas on nitrogen solution from an arc plasma into liquid iron has been investigated by melting iron in an atmosphere of nitrogen and argon using an arc plasma. Results show that both the rate of nitrogen absorption and the steady-state (plateau) solubility are increased as the ...

  14. Absorption of carbon dioxide, nitrous oxide, ethane and nitrogen by 1-alkyl-3-methylimidazolium (C(n)mim, n = 2,4,6) tris(pentafluoroethyl)trifluorophosphate ionic liquids (eFAP). (United States)

    Almantariotis, D; Stevanovic, S; Fandiño, O; Pensado, A S; Padua, A A H; Coxam, J-Y; Costa Gomes, M F


    We measured the densities of 1-alkyl-3-methylimidazolium (C(n)mim, n = 2,4,6) tris(pentafluoroethyl)trifluorophosphate ionic liquids (eFAP) as a function of temperature and pressure and their viscosities as a function of temperature. These ionic liquids are less viscous than those based in the same cations but with other anions such as bis(trifluoromethylsulfonyl)imide. The ionic liquids studied are only partially miscible with water, their solubility increasing with the size of the alkyl side-chain of the cation and with temperature (from x(H(2)O) = 0.20 ± 0.03 for [C(4)mim][eFAP] at 303.10 K to x(H(2)O) = 0.49 ± 0.07 for [C(6)mim][eFAP] at 315.10 K). The solubility of carbon dioxide, nitrous oxide, ethane, and nitrogen in the three ionic liquids was measured as a function of temperature and at pressures close to atmospheric. Carbon dioxide and nitrous oxide are the more soluble gases with mole fraction solubilities of the order of 3 × 10(-2) at 303 K. The solubility of these gases does not increase linearly with the size of the alkyl-side chain of the cation. The solubilities of ethane and nitrogen are much lower than those of carbon dioxide and nitrous oxide (mole fractions 60% and 90% lower, respectively). The higher solubility of CO(2) and N(2)O can be explained by more favorable interactions between the solutes and the polar region of the ionic liquids as shown by the enthalpies of solvation determined experimentally and by the calculation of the site-site solute-solvent radial distribution functions using molecular simulation.

  15. Bubble Point Measurements with Liquid Methane of a Screen Capillary Liquid Acquisition Device (United States)

    Jurns, John M.; McQuillen, John B.


    Liquid acquisition devices (LADs) can be utilized within a propellant tank in space to deliver single-phase liquid to the engine in low gravity. One type of liquid acquisition device is a screened gallery whereby a fine mesh screen acts as a bubble filter and prevents the gas bubbles from passing through until a crucial pressure differential condition across the screen, called the bubble point, is reached. This paper presents data for LAD bubble point data in liquid methane (LCH4) for stainless steel Dutch twill screens with mesh sizes of 325 by 2300 and 200 by 1400 wires per inch. Data is presented for both saturated and sub-cooled LCH4, and is compared with predicted values.

  16. Screen Channel Liquid Acquisition Device Outflow Tests in Liquid Hydrogen (United States)

    Hartwig, Jason W.; Chato, David J.; McQuillen, J. B.; Vera, J.; Kudlac, M. T.; Quinn, F. D.


    This paper presents experimental design and test results of the recently concluded 1-g inverted vertical outflow testing of two 325x2300 full scale liquid acquisition device (LAD) channels in liquid hydrogen (LH2). One of the channels had a perforated plate and internal cooling from a thermodynamic vent system (TVS) to enhance performance. The LADs were mounted in a tank to simulate 1-g outflow over a wide range of LH2 temperatures (20.3 - 24.2 K), pressures (100 - 350 kPa), and flow rates (0.010 - 0.055 kg/s). Results indicate that the breakdown point is dominated by liquid temperature, with a second order dependence on mass flow rate through the LAD. The best performance is always achieved in the coldest liquid states for both channels, consistent with bubble point theory. Higher flow rates cause the standard channel to break down relatively earlier than the TVS cooled channel. Both the internal TVS heat exchanger and subcooling the liquid in the propellant tank are shown to significantly improve LAD performance.

  17. Persistent-current switch for pancake coils of rare earth-barium-copper-oxide high-temperature superconductor: Design and test results of a double-pancake coil operated in liquid nitrogen (77–65 K) and in solid nitrogen (60–57 K)

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Timing; Michael, Philip C.; Bascuñán, Juan; Iwasa, Yukikazu, E-mail: [Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139 (United States); Voccio, John [Wentworth Institute of Technology, 550 Huntington Ave, Boston, Massachusetts 02115 (United States); Hahn, Seungyong [National High Magnetic Field Laboratory, Florida State University, Tallahassee, 2031 Paul Dirac Drive, Florida 32310 (United States)


    We present design and test results of a superconducting persistent current switch (PCS) for pancake coils of rare-earth-barium-copper-oxide, REBCO, high-temperature superconductor (HTS). Here, a REBCO double-pancake (DP) coil, 152-mm ID, 168-mm OD, 12-mm high, was wound with a no-insulation technique. We converted a ∼10-cm long section in the outermost layer of each pancake to a PCS. The DP coil was operated in liquid nitrogen (77–65 K) and in solid nitrogen (60–57 K). Over the operating temperature ranges of this experiment, the normal-state PCS enabled the DP coil to be energized; thereupon, the PCS resumed the superconducting state and the DP coil field decayed with a time constant of 100 h, which would have been nearly infinite, i.e., persistent-mode operation, were the joint across the coil terminals superconducting.

  18. Thermocapillary flow with evaporation and condensation and its effect on liquid retention in low-G fluid acquisition devices (United States)

    Schmidt, George R.


    The steady motion, thermal and free surface behavior of a volatile, wetting liquid in microgravity are studied using scaling and numerical techniques. The objective is to determine whether the thermocapillary and two-phase convection arising from thermodynamic nonequilibrium along the porous surfaces of spacecraft liquid acquisition devices could cause the retention failures observed with liquid hydrogen and heated vapor pressurant. Why these devices seem immune to retention loss when pressurized with heated helium or heated directly through the porous structure was also examined. Results show that highly wetting fluids exhibit large negative and positive dynamic pressure gradients towards the meniscus interline when superheated and subcooled, respectively. With superheating, the pressure variation and recoil force arising from liquid/vapor phase change exert the same influence on surface morphology and promote retention. With subcooling, however, the pressure distribution produces a suction that degrades mechanical equilibrium of the surface. This result indicates that thermocapillary-induced deformation arising from subcooling and condensation is the likely cause for retention loss. In addition, increasing the level of nonequilibrium by reducing accommodation coefficient suppresses deformation and explains why this failure mode does not occur in instances of direct screen heating or pressurization with a heated inert gas.

  19. High-temperature superconducting radiofrequency probe for magnetic resonance imaging applications operated below ambient pressure in a simple liquid-nitrogen cryostat (United States)

    Lambert, Simon; Ginefri, Jean-Christophe; Poirier-Quinot, Marie; Darrasse, Luc


    The present work investigates the joined effects of temperature and static magnetic field on the electrical properties of a 64 MHz planar high-temperature superconducting (HTS) coil, in order to enhance the signal-to-noise ratio (SNR) in nuclear magnetic resonance (NMR) applications with a moderate decrease of the HTS coil temperature (THTS). Temperature control is provided with accuracy better than 0.1 K from 80 to 66 K by regulating the pressure of the liquid nitrogen bath of a dedicated cryostat. The actual temperature of the HTS coil is obtained using a straightforward wireless method that eliminates the risks of coupling electromagnetic interference to the HTS coil and of disturbing the static magnetic field by DC currents near the region of interest. The resonance frequency ( f0) and the quality factor (Q) of the HTS coil are measured as a function of temperature in the 0-4.7 T field range with parallel and orthogonal orientations relative to the coil plane. The intrinsic HTS coil sensitivity and the detuning effect are then analyzed from the Q and f0 data. In the presence of the static magnetic field, the initial value of f0 in Earth's field could be entirely recovered by decreasing THTS, except for the orthogonal orientation above 1 T. The improvement of Q by lowering THTS was substantial. From 80 to 66 K, Q was multiplied by a factor of 6 at 1.5 T in orthogonal orientation. In parallel orientation, the maximum measured improvement of Q from 80 K to 66 K was a factor of 2. From 80 to 66 K, the improvement of the RF sensitivity relative to the initial value at the Earth's field and ambient pressure was up to 4.4 dB in parallel orientation. It was even more important in orthogonal orientation and continued to increase, up to 8.4 dB, at the maximum explored field of 1.5 T. Assuming that the noise contributions from the RF receiver are negligible, the SNR improvement using enhanced HTS coil cooling in NMR experiments was extracted from Q measurements either

  20. A numerical framework for bubble transport in a subcooled fluid flow (United States)

    Jareteg, Klas; Sasic, Srdjan; Vinai, Paolo; Demazière, Christophe


    In this paper we present a framework for the simulation of dispersed bubbly two-phase flows, with the specific aim of describing vapor-liquid systems with condensation. We formulate and implement a framework that consists of a population balance equation (PBE) for the bubble size distribution and an Eulerian-Eulerian two-fluid solver. The PBE is discretized using the Direct Quadrature Method of Moments (DQMOM) in which we include the condensation of the bubbles as an internal phase space convection. We investigate the robustness of the DQMOM formulation and the numerical issues arising from the rapid shrinkage of the vapor bubbles. In contrast to a PBE method based on the multiple-size-group (MUSIG) method, the DQMOM formulation allows us to compute a distribution with dynamic bubble sizes. Such a property is advantageous to capture the wide range of bubble sizes associated with the condensation process. Furthermore, we compare the computational performance of the DQMOM-based framework with the MUSIG method. The results demonstrate that DQMOM is able to retrieve the bubble size distribution with a good numerical precision in only a small fraction of the computational time required by MUSIG. For the two-fluid solver, we examine the implementation of the mass, momentum and enthalpy conservation equations in relation to the coupling to the PBE. In particular, we propose a formulation of the pressure and liquid continuity equations, that was shown to correctly preserve mass when computing the vapor fraction with DQMOM. In addition, the conservation of enthalpy was also proven. Therefore a consistent overall framework that couples the PBE and two-fluid solvers is achieved.

  1. Exploring the Structure of Nitrogen-Rich Ionic Liquids and Their Binding to the Surface of Oxide-Free Boron Nanoparticles (United States)


    nanoparticulate samples were washed with ethanol to remove unbound ILs, air-dried, and then pressed onto a diamond crystal with a Platinum ATR QuickSnap...amino group on [MAT]+ and the lone pairs in one or more nitrogen atoms of [DCA]−. IV. CONCLUSIONS Nanoparticulate boron powder dispersed in, and

  2. Influence of fermentation liquid from waste activated sludge on anoxic/oxic- membrane bioreactor performance: Nitrogen removal, membrane fouling and microbial community. (United States)

    Han, Xiaomeng; Zhou, Zhen; Mei, Xiaojie; Ma, Yan; Xie, Zhenfang


    In order to investigate effects of waste activated sludge (WAS) fermentation liquid on anoxic/oxic- membrane bioreactor (A/O-MBR), two A/O-MBRs with and without WAS fermentation liquid addition were operated in parallel. Results show that addition of WAS fermentation liquid clearly improved denitrification efficiency without deterioration of nitrification, while severe membrane fouling occurred. WAS fermentation liquid resulted in an elevated production of proteins and humic acids in bound extracellular polymeric substance (EPS) and release of organic matter with high MW fractions in soluble microbial product (SMP) and loosely bound EPS (LB-EPS). Measurement of deposition rate and fluid structure confirmed increased fouling potential of SMP and LB-EPS. γ-Proteobacteria and Ferruginibacter, which can secrete and export EPS, were also found to be abundant in the MBR with WAS fermentation liquid. It is implied that when WAS fermentation liquid was applied, some operational steps to control membrane fouling should be employed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Indicators: Nitrogen (United States)

    Nitrogen, like phosphorus, is a critical nutrient required for all life. Nitrogen can occur in rivers and streams, lakes, and coastal waters in several forms including ammonia (NH3), nitrates (NO3), and nitrites (NO2).

  4. Ionic Liquid Epoxy Resin Monomers (United States)

    Paley, Mark S. (Inventor)


    Ionic liquid epoxide monomers capable of reacting with cross-linking agents to form polymers with high tensile and adhesive strengths. Ionic liquid epoxide monomers comprising at least one bis(glycidyl) N-substituted nitrogen heterocyclic cation are made from nitrogen heterocycles corresponding to the bis(glycidyl) N-substituted nitrogen heterocyclic cations by a method involving a non-nucleophilic anion, an alkali metal cation, epichlorohydrin, and a strong base.

  5. Development of a 1000 kVA oxide superconducting transformer cooled by liquid nitrogen. 4. Ac loss properties.; Ekitai chisso reikyaku 1000 kVA sankabutsu chodendo hen'atsuki no kaihatsu 4. Koryu sonshitsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Iwakuma, M.; Fukuda, Y.; Matsumura, K. [Kyushu Univ., Fukuoka (JP)] [and others


    In this study group, it developed the liquid nitrogen cooling 22kV/6.9kV-1000kVA single phase superconducting transformer using the Bi2223 superconducting wire rod with the aim of the superconduction of the transformer for urban area underground substation this time. In this paper, ac loss characteristics of the superconductive winding are reported. In developed superconductive winding, the ac loss occupies over half of all thermal load, and it becomes important characteristics, which decide necessary cooling unit capacity and equipment efficiency. In this study, it put principal objective for the establishment of ac loss evaluation technique in the design and ac loss measuring technique of actual equipment. (NEDO)

  6. A Densified Liquid Methane Delivery System for the Altair Ascent Stage (United States)

    Tomsik, Thomas M.; Johnson, Wesley L.; Smudde, Todd D.; Femminineo, Mark F.; Schnell, Andrew R.


    The Altair Lunar Lander is currently carrying options for both cryogenic and hypergolic ascent stage propulsion modules. The cryogenic option uses liquid methane and liquid oxygen to propel Altair from the lunar surface back to rendezvous with the Orion command module. Recent studies have determined that the liquid methane should be densified by subcooling it to 93 K in order to prevent over-pressurization of the propellant tanks during the 210 day stay on the lunar surface. A trade study has been conducted to determine the preferred method of producing; loading, and maintaining the subcooled, densified liquid methane onboard Altair from a ground operations perspective. The trade study took into account the limitations in mass for the launch vehicle and the mobile launch platform as well as the historical reliability of various components and their thermal efficiencies. Several unique problems were encountered, namely delivering a small amount of a cryogenic propellant to a flight tank that is positioned over 350 ft above the launch pad as well as generating the desired delivery temperature of the methane at 93 K which is only 2.3 K above the methane triple point of 90.7 K. Over 20 methods of subcooled liquid methane production and delivery along with the associated system architectures were investigated to determine the best solutions to the problem. The top four cryogenic processing solutions were selected for further evaluation and detailed thermal modeling. This paper describes the results of the preliminary trade analysis of the 20 plus methane densification methods considered. The results of the detailed analysis will be briefed to the Altair Project Office and their propulsion team as well as the Ground Operations Project Office before the down-select is made between cryogenic and hypergolic ascent stages in August 2010.

  7. Exploring symbiotic nitrogen fixation and assimilation in pea root nodules by in vivo 15N nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry

    DEFF Research Database (Denmark)

    Scharff, A.M.; Egsgaard, H.; Hansen, P.E.


    indicate that ammonium is located in the bacteroids. The observed N-15-labeled amino acids, glutamine/glutamate and asparagine (Asn), apparently reside in a different compartment, presumably the plant cytoplasm, because no changes in the expected in vivo N-15 chemical shifts were observed. Extensive N-15...... the physiological state of the metabolically active nodules. The nodules were extracted after the NMR studies and analyzed for total soluble amino acid pools and N-15 labeling of individual amino acids by liquid chromatography-mass spectrometry. A substantial pool of free ammonium was observed by N-15 NMR...... labeling of Asn was observed by liquid chromatography-mass spectrometry, which is consistent with the generally accepted role of Asn as the end product of primary N assimilation in pea nodules. However, the Asn N-15 amino signal was absent in in vivo N-15 NMR spectra, which could be because...

  8. Validation of a rapid method of analysis using ultrahigh-performance liquid chromatography - tandem mass spectrometry for nitrogen-rich adulterants in nutritional food ingredients. (United States)

    Draher, Jon; Pound, Vickie; Reddy, Todime M


    A method for the rapid quantification of 9 potential nitrogen-rich economic adulterants (dicyandiamide, urea, biuret, cyromazine, amidinourea, ammeline, amidinourea, melamine, and cyanuric acid) in five milk and soy derived nutritional ingredients, i.e. whole milk powder, nonfat dry milk, milk protein concentrate, sodium caseinate, and soy protein isolate has been developed and validated for routine use. The samples were diluted tenfold with water followed by treatment with 2% formic acid and acetonitrile to precipitate proteins. Sample extracts were analyzed using hydrophilic interaction chromatography and tandem mass spectrometry (HILIC-MS/MS) under both positive and negative modes. Stable isotope labeled internal standards were used to ensure accurate quantification. In multi-day validation experiments, the average accuracies, relative standard deviations (RSD), and method detection limits (MDL) for all analytes in whole milk powder were 82-101%, 6-13%, and 0.1mg/kg-7 mg/kg, respectively. The retention times of the analytes in matrix spiked controls were within ± 0.06 min of the average retention times of the corresponding analytes in calibration standards. The validated method was proven to be rugged for routine use to quantify the presence of 9 nitrogen-rich compounds in milk and soy derived ingredients and to provide a defense from economically motivated adulteration. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. A CFD Analysis of the Characteristics of the Thermal Mixing Under the Transient of the Steam Discharge in a Subcooled Water Tank

    Energy Technology Data Exchange (ETDEWEB)

    Kang, H. S.; Kim, Y. S.; Jun, H. G.; Youn, Y. J.; Song, C. H


    A CFD benchmark calculation for the test results was performed for 30 seconds to develop the methodology of numerical analysis for the thermal mixing between the steam and the subcooled water and to apply it into the APR1400 IRWST. In the CFD analysis, the grid model simulating the test facility was developed by the axisymmetric condition and the steam condensation phenomena by the direct contact was modelled by the steam condensation region model. Thermal mixing phenomenon was treated as an incompressible flow, a free surface flow, a turbulent flow, and a buoyancy flow. The comparison of the CFD results with the test data showed a good agreement as a whole, but a small temperature difference was locally found at some locations. The CFD results at some locations showed a higher temperature value and the increasing speed than those of the test results. This difference may have arisen from the fact the temperature and velocity of the calculated condensed water were higher than the real values. However, this CFD analysis methodology can surely simulate the thermal mixing behavior in the subcooled water tank with the minor limit. We can anticipate that the numerical model for the thermal mixing taking place for a long time in the IRWST of APR1400 can be developed by this methodology.

  10. A charged aerosol detector/chemiluminescent nitrogen detector/liquid chromatography/mass spectrometry system for regular and fragment compound analysis in drug discovery. (United States)

    Jiang, Yutao; Hascall, Daniel; Li, Delia; Pease, Joseph H


    In this paper, we introduce a high throughput LCMS/UV/CAD/CLND system that improves upon previously reported systems by increasing both the quantitation accuracy and the range of compounds amenable to testing, in particular, low molecular weight "fragment" compounds. This system consists of a charged aerosol detector (CAD) and chemiluminescent nitrogen detector (CLND) added to a LCMS/UV system. Our results show that the addition of CAD and CLND to LCMS/UV is more reliable for concentration determination for a wider range of compounds than either detector alone. Our setup also allows for the parallel analysis of each sample by all four detectors and so does not significantly increase run time per sample. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Experimental high temperature coefficients of compressibility and expansivity of liquid sodium and other related properties

    Energy Technology Data Exchange (ETDEWEB)

    Das Gupta, S.


    The subcooled compressibility of liquid sodium was directly measured up to 200 atm between 900 K and 1867 K, utilizing a new multi-property apparatus which was previously tested with water. The experimental data were correlated by a 6-term equation with a standard deviation of 9.2 percent. The equation can be used to estimate the subcooled compressibilities and densities of liquid sodium up to 2300 K and 500 ata. The thermal expansion of liquid sodium was also measured along the isobars 1 ata, 28.9 ata and 69 ata. Densities within 1 percent of those obtained from the compressibilities were obtained. The above compressibility data were used to calculate the thermal pressure coefficient of saturated liquid sodium. Also, Bhise and Bonilla's correlations for the vapor pressure and the saturated liquid density of sodium were improved by including more data in the analysis. The critical temperature and density were thus reestimated as 2508.7 K and 0.2141 g/cc. Furthermore, a new correlation was developed to determine the heat of vaporization of sodium up to the critical point, which was then used to estimate the internal energy and the entropy of vaporization and the saturated vapor density of sodium up to the critical point.

  12. Experimental Investigation of Jet-Induced Mixing of a Large Liquid Hydrogen Storage Tank (United States)

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


    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. Low evaporation rate storage media for cryogenic liquids Project (United States)

    National Aeronautics and Space Administration — Considerable design work has been devoted to the development of cryogenic liquid storage containers. Containers which hold cryogenic liquids such as liquid nitrogen,...

  14. Emergence of innovative properties by replacement of nitrogen atom with phosphorus atom in quaternary ammonium ionic liquids: Insights from ab initio calculations and MD simulations (United States)

    Ghatee, Mohammad Hadi; Bahrami, Maryam


    We investigate to contrasting structure, dynamic and thermophysical properties of quaternary ammonium and phosphonium ionic liquids (ILs) based on triethylalkylammonium [N222n]+ and triethylalkylphosphonium [P222n]+ cations (n = 5, 8, 12) and (bis(trifluoromethylsulfonyl)imide) anion [NTf2]- by quantum chemical calculations (QCC) and molecular dynamics (MD) simulations. QCCs conform to previous studies, showing that phosphonium cation alkyl chain rotational-energy-barrier is lower than ammonium cation. These molecular nature leads to no appreciable differences in their liquid density. However, their simulated transport properties (self-diffusion, conductivity, etc) are appreciably different. In particular, viscosity of phosphoniums are much lower than ammoniums. Ammoniums make nano-scale structural domains larger than phosphoniums. Employed analysis, vector re-orientational dynamics, ion-pair lifetime and nanostructure domain are in favor of faster dynamic for phosphoniums than ammoniums. [NTf2]- anion features a long lived pairing with ammoniums than phosphoniums. Overall, phosphoniums possess higher transference number, higher conductivity, and appreciably lower viscosity favorable for higher electrochemical performances.

  15. Liquid hydrogen in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Yasumi, S. [Iwatani Corp., Osaka (Japan). Dept. of Overseas Business Development


    Japan's Iwatani Corporation has focused its attention on hydrogen as the ultimate energy source in future. Unlike the United States, hydrogen use and delivery in liquid form is extremely limited in the European Union and in Japan. Iwatani Corporation broke through industry stereotypes by creating and building Hydro Edge Co. Ltd., Japan's largest liquid hydrogen plant. It was established in 2006 as a joint venture between Iwatani and Kansai Electric Power Group in Osaka. Hydro Edge is Japan's first combined liquid hydrogen and ASU plant, and is fully operational. Liquid oxygen, liquid nitrogen and liquid argon are separated from air using the cryogenic energy of liquefied natural gas fuel that is used for power generation. Liquid hydrogen is produced efficiently and simultaneously using liquid nitrogen. Approximately 12 times as much hydrogen in liquid form can be transported and supplied as pressurized hydrogen gas. This technology is a significant step forward in the dissemination and expansion of hydrogen in a hydrogen-based economy.

  16. Reduction of nitrogen oxides (NO{sub x}) production in a liquid fuel-oil diffusion flame by acoustic excitation; Reduction de la production des oxydes d`azote (NO{sub x}) dans une flamme de diffusion a fioul liquide par excitation acoustique

    Energy Technology Data Exchange (ETDEWEB)

    Delabroy, O.; Haile, E.; Veynante, D.; Lacas, F.; Candel, S. [Ecole Centrale de Paris, Laboratoire EM2C. CNRS, 92 - Chatenay-Malabry (France)


    The control of nitrogen oxides (NO{sub x}) emissions will become a major challenge in the forthcoming years, in the domain of automotive industry or industrial burners. Pulsed combustion offers an imaginative solution which does not affect the combustion efficiency. In this paper, the efficiency of this method is demonstrated using the burner of a 20 kW domestic boiler. The actuator is simply installed on the air intake. Two types of actuators have been tested successfully: a loudspeaker and a rotative valve. Both can produce 100 to 1000 Hz frequencies and can lead to a reduction of 20% of NO{sub x} emissions. The feasibility of the concept is also demonstrated on a 840 kW liquid fuel-oil burner. The mechanisms involved during an excitation are explained using the CH{sup *} radical imaging. Results show an important reorganization of the flow and of the flame structure. During each excitation cycle, an annular swirl occurs at the leading edge of the flame catching and develops during downflow convection. These results give precious information on this new concept of nitrogen oxides reduction using acoustic excitation. (J.S.) 18 refs.

  17. Liquids and liquid mixtures

    CERN Document Server

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


    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

  18. 46 CFR 151.50-36 - Argon or nitrogen. (United States)


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Argon or nitrogen. 151.50-36 Section 151.50-36 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-36 Argon or nitrogen. (a) A cargo tank that contains argon or nitrogen and that has a maximum allowable working pressure of 172 kPa (25...

  19. Characterization of organic nitrogen in IBCSP coals

    Energy Technology Data Exchange (ETDEWEB)

    Kruge, M.A.


    The overall objective of this study was to determine the content and distribution of organic nitrogen in a series of IBCSP coals and their isolated macerals. The specific objectives were: to determine the bulk nitrogen contents for coals, isolated macerals, oxidation products and residues, solvent extracts and their liquid chromatographic fractions, and pyrolyzates; to determine the distribution of organic nitrogen in all coal derivatives enumerated in Objective 1 which are Gas Chromatography (GC)-amenable. This will be accomplished by GC-Thermionic Specific Detectors; to determine the molecular structure of the major nitrogen compounds detected in Objective 2, using mass spectrometry.

  20. Biological upgrading of coal liquids. Final report

    Energy Technology Data Exchange (ETDEWEB)



    A large number of bacterial enrichments have been developed for their ability to utilize nitrogen and sulfur in coal liquids and the model compound naphtha. These bacteria include the original aerobic bacteria isolated from natural sources which utilize heteroatom compounds in the presence of rich media, aerobic nitrogen-utilizing bacteria and denitrifying bacteria. The most promising isolates include Mix M, a mixture of aerobic bacteria; ER15, a pyridine-utilizing isolate; ERI6, an aniline-utilizing isolate and a sewage sludge isolate. Culture optimization experiments have led to these bacteria being able to remove up to 40 percent of the sulfur and nitrogen in naphtha and coal liquids in batch culture. Continuous culture experiments showed that the coal liquid is too toxic to the bacteria to be fed without dilution or extraction. Thus either semi-batch operation must be employed with continuous gas sparging into a batch of liquid, or acid extracted coal liquid must be employed in continuous reactor studies with continuous liquid flow. Isolate EN-1, a chemical waste isolate, removed 27 percent of the sulfur and 19 percent of the nitrogen in fed batch experiments. Isolate ERI5 removed 28 percent of the nitrogen in coal liquid in 10 days in fed batch culture. The sewage sludge isolate removed 22.5 percent of the sulfur and 6.5 percent of the nitrogen from extracted coal liquid in continuous culture, and Mix M removed 17.5 percent of the nitrogen from medium containing extracted coal liquid. An economic evaluation has been prepared for the removal of nitrogen heteroatom compounds from Wilsonville coal liquid using acid extraction followed by fermentation. Similar technology can be developed for sulfur removal. The evaluation indicates that the nitrogen heteroatom compounds can be removed for $0.09/lb of coal liquid treated.

  1. Fundamental studies on the switching in liquid nitrogen environment using vacuum switches for application in future high-temperature superconducting medium-voltage power grids; Grundsatzuntersuchungen zum Schalten in Fluessigstickstoff-Umgebung mit Vakuumschaltern zur Anwendung in zukuenftigen Hochtemperatur-Supraleitungs-Mittelspannungsnetzen

    Energy Technology Data Exchange (ETDEWEB)

    Golde, Karsten


    By means of superconducting equipment it is possible to reduce the transmission losses in distribution networks while increasing the transmission capacity. As a result even saving a superimposed voltage level would be possible, which can put higher investment costs compared to conventional equipment into perspective. For operation of superconducting systems it is necessary to integrate all equipment in the cooling circuit. This also includes switchgears. Due to cooling with liquid nitrogen, however, only vacuum switching technology comes into question. Thus, the suitability of vacuum switches is investigated in this work. For this purpose the mechanics of the interrupters is considered first. Material investigations and switching experiments at ambient temperature and in liquid nitrogen supply information on potential issues. For this purpose, a special pneumatic construction is designed, which allows tens of thousands of switching cycles. Furthermore, the electrical resistance of the interrupters is considered. Since the contact system consists almost exclusively of copper, a remaining residual resistance and appropriate thermal losses must be considered. Since they have to be cooled back, an appropriate evaluation is given taking environmental parameters into account. The dielectric strength of vacuum interrupters is considered both at ambient temperature as well as directly in liquid nitrogen. For this purpose different contact distances are set at different interrupter types. A distinction is made between internal and external dielectric strength. Conditioning and deconditioning effects are minimized by an appropriate choice of the test circuit. The current chopping and resulting overvoltages are considered to be one of the few drawbacks of vacuum switching technology. Using a practical test circuit the height of chopping current is determined and compared for different temperatures. Due to strong scattering the evaluation is done using statistical methods. At

  2. Nitrogen tank

    CERN Multimedia


    Wanted The technical file about the pressure vessel RP-270 It concerns the Nitrogen tank, 60m3, 22 bars, built in 1979, and installed at Point-2 for the former L3 experiment. If you are in possession of this file, or have any files about an equivalent tank (probably between registered No. RP-260 and -272), please contact Marc Tavlet, the ALICE Glimos.

  3. Small, submersible, centrifugal pump for liquid nitrogen

    DEFF Research Database (Denmark)

    Rustad, B.M.; Nielsen, A.; Passell, L.


    Full details are given of a pump designed to circulate several liters/min. It can be evacuated before use to exclude oxygen and may be used at pressures of several atmospheres.......Full details are given of a pump designed to circulate several liters/min. It can be evacuated before use to exclude oxygen and may be used at pressures of several atmospheres....

  4. On the Application of Image Processing Methods for Bubble Recognition to the Study of Subcooled Flow Boiling of Water in Rectangular Channels (United States)

    Paz, Concepción; Conde, Marcos; Porteiro, Jacobo; Concheiro, Miguel


    This work introduces the use of machine vision in the massive bubble recognition process, which supports the validation of boiling models involving bubble dynamics, as well as nucleation frequency, active site density and size of the bubbles. The two algorithms presented are meant to be run employing quite standard images of the bubbling process, recorded in general-purpose boiling facilities. The recognition routines are easily adaptable to other facilities if a minimum number of precautions are taken in the setup and in the treatment of the information. Both the side and front projections of subcooled flow-boiling phenomenon over a plain plate are covered. Once all of the intended bubbles have been located in space and time, the proper post-process of the recorded data become capable of tracking each of the recognized bubbles, sketching their trajectories and size evolution, locating the nucleation sites, computing their diameters, and so on. After validating the algorithm’s output against the human eye and data from other researchers, machine vision systems have been demonstrated to be a very valuable option to successfully perform the recognition process, even though the optical analysis of bubbles has not been set as the main goal of the experimental facility. PMID:28632158

  5. On the Application of Image Processing Methods for Bubble Recognition to the Study of Subcooled Flow Boiling of Water in Rectangular Channels. (United States)

    Paz, Concepción; Conde, Marcos; Porteiro, Jacobo; Concheiro, Miguel


    This work introduces the use of machine vision in the massive bubble recognition process, which supports the validation of boiling models involving bubble dynamics, as well as nucleation frequency, active site density and size of the bubbles. The two algorithms presented are meant to be run employing quite standard images of the bubbling process, recorded in general-purpose boiling facilities. The recognition routines are easily adaptable to other facilities if a minimum number of precautions are taken in the setup and in the treatment of the information. Both the side and front projections of subcooled flow-boiling phenomenon over a plain plate are covered. Once all of the intended bubbles have been located in space and time, the proper post-process of the recorded data become capable of tracking each of the recognized bubbles, sketching their trajectories and size evolution, locating the nucleation sites, computing their diameters, and so on. After validating the algorithm's output against the human eye and data from other researchers, machine vision systems have been demonstrated to be a very valuable option to successfully perform the recognition process, even though the optical analysis of bubbles has not been set as the main goal of the experimental facility.

  6. On the Application of Image Processing Methods for Bubble Recognition to the Study of Subcooled Flow Boiling of Water in Rectangular Channels

    Directory of Open Access Journals (Sweden)

    Concepción Paz


    Full Text Available This work introduces the use of machine vision in the massive bubble recognition process, which supports the validation of boiling models involving bubble dynamics, as well as nucleation frequency, active site density and size of the bubbles. The two algorithms presented are meant to be run employing quite standard images of the bubbling process, recorded in general-purpose boiling facilities. The recognition routines are easily adaptable to other facilities if a minimum number of precautions are taken in the setup and in the treatment of the information. Both the side and front projections of subcooled flow-boiling phenomenon over a plain plate are covered. Once all of the intended bubbles have been located in space and time, the proper post-process of the recorded data become capable of tracking each of the recognized bubbles, sketching their trajectories and size evolution, locating the nucleation sites, computing their diameters, and so on. After validating the algorithm’s output against the human eye and data from other researchers, machine vision systems have been demonstrated to be a very valuable option to successfully perform the recognition process, even though the optical analysis of bubbles has not been set as the main goal of the experimental facility.

  7. IR-thermography-based investigation of critical heat flux in subcooled flow boiling of water at atmospheric and high pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bucci, Matteo [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Seong, Jee H. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Buongiorno, Jdacopo [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Richenderfer, Andrew [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Kossolapov, A. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)


    Here we report on MIT’s THM work in Q4 2016 and Q1 2017. The goal of this project is to design, construct and execute tests of flow boiling critical heat flux (CHF) at high-pressure using high-resolution and high-speed video and infrared (IR) thermometry, to generate unique data to inform the development of and validate mechanistic boiling heat transfer and CHF models. In FY2016, a new test section was designed and fabricated. Data was collected at atmospheric conditions at 10, 25 and 50 K subcoolings, and three mass fluxes, i.e. 500, 750 and 1000 kg/m2/s. Starting in Q4 2016 and continuing forward, new post-processing techniques have been developed to analyze the data collected. These new algorithms analyze the time-dependent temperature and heat flux distributions to calculate nucleation site density, nucleation frequency, growth and wait time, dry area fraction, and the complete heat flux partitioning. In Q1 2017 a new flow boiling loop was designed and constructed to support flow boiling tests up 10 bar pressure and 180 °C. Initial shakedown and testing has been completed. The flow loop and test section are now ready to begin high-pressure flow boiling testing.

  8. DNB heat flux in forced convection of liquid hydrogen for a wire set in central axis of vertically mounted flow channel (United States)

    Matsumoto, T.; Shirai, Y.; Shiotsu, M.; Fujita, K.; Kainuma, T.; Tatsumoto, H.; Naruo, Y.; Kobayashi, H.; Nonaka, S.; Inatani, Y.


    Liquid hydrogen has excellent physical properties, high latent heat and low viscosity of liquid, as a coolant for superconductors like MgB2. The knowledge of Departure from Nucleate Boiling (DNB) heat flux of liquid hydrogen is necessary for designing and cooling analysis of high critical temperature superconducting devices. In this paper, DNB heat fluxes of liquid hydrogen were measured under saturated and subcooled conditions at absolute pressures of 400, 700 and 1100 kPa for various flow velocities. Two wire test heaters made by Pt-Co alloy with the length of 200 mm and the diameter of 0.7 mm were used. And these round heaters were set in central axis of a flow channel made of Fiber Reinforced Plastic (FRP) with inner diameters of 8 mm and 12 mm. These test bodies were vertically mounted and liquid hydrogen flowed upward through the channel. From these experimental values, the correlations of DNB heat flux under saturated and subcooled conditions are presented in this paper.

  9. Capacitive level meter for liquid hydrogen


    Matsumoto, Koichi; Sobue, Masamitsu; Asamoto, Kai; Nishimura, Yuta; Abe, Satoshi; Numazawa, Takenori


    A capacitive level meter working at low temperatures was made to use in magnetic refrigerator for hydrogen liquefaction. The liquid level was measured from the capacitance between parallel electrodes immersed in the liquid. The meter was tested for liquid nitrogen, hydrogen, and helium. The operation was successful using an AC capacitance bridge. The estimated sensitivity of the meter is better than 0.2 mm for liquid hydrogen. The meter also worked with pressurized hydrogen. © 2010.

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

    National Research Council Canada - National Science Library

    Chehroudi, B


    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...

  11. The effect the effectiveness of the liquid suction heat exchanger to performance of cold storage with refrigerant R22, R404A and R290/R600a (United States)

    Prayudi, Nurhasanah, Roswati; Diantari, Retno Aita


    Storage space requirements with a large refrigeration capacity they use refrigerants types R22 and R404A. This research to develop alternative technologies to meet the needs of storage space with a large refrigeration capacity. Liquid suction subcooling technology is typically used to obtain improve refrigeration effect at vapor compression refrigeration system. Liquid suction heat exchanger subcooling used a type of tube in tube heat exchanger installed between the condenser and the capillary tube before entering the evaporator. Refrigerant used in this research is R22, R404A, and mixture refrigerant R290/R600a [50:50]. In steady state condition with subcooling temperature evaporator with R290/R600a lower reaches -30°C, lower than R404a and R22 is -24°C and -22°C. Liquid suction heat exchanger subcooling effect on ΔTsub. The cooling effect by the mixture refrigerant of R290/R600a greater than R404a and R22, and liquid suction heat exchanger increase refrigeration capacity index (RCI). The average increase in RCI respectively 3.91%, 7.78%, and 11.87%. Work compressor and compressor work index (CWI) with a mixture refrigerant of R290/R600a greater than R404a and R22, the average work compressor and the working compressor index is greatest mixture refrigerant R290/R600a. CWI respectively is an average of 5.68%, 8.82%, and 11.82%. The average COP, their, liquid suction heat exchanger, respectively are 3.38, 3.18 and 2.63. COPRS with a mixture refrigerant of R290/R600a [50:50] is bigger than the R22 and R404a, and the average COPRS is 5:01%, 5.95%, and 7:41%. A mixture refrigerant R290/R600a [50:50] have the same characteristics as R404a, which can be used as a substitute for refrigerant R22 and R404A.

  12. Phases and defects upon the solidification of nitrogen-alloyed stainless steels (United States)

    Svyazhin, A. G.; Kaputkina, L. M.; Bazhenov, V. E.; Skuza, Z.; Siwka, E.; Kindop, V. E.


    One of the technological problems in alloying molten steels with nitrogen is the precipitation of nitrogen into the gas phase upon the solidification of steels and the formation of nitrogen bubbles and porosity in steel ingots with the result that potentials of nitrogen as an alloying element are used incompletely. The formation of bubbles and pores in nitrogen-alloyed stainless steels occurs heterogeneously and is limited by the desorption rate of nitrogen from the molten-metal surface into bubbles. For this reason, it is convenient to determine the critical nitrogen concentration in steels as the concentration at which in the process of equilibrium solidification the content of nitrogen in the residual liquid phase at all temperatures of semisolid state does not exceed its solubility in the residual liquid at a given pressure. Hereafter, this concentration should be refined experimentally for concrete conditions of solidification. To calculate the nitrogen concentration in the arising phases, a Thermo-Calc software can be employed.

  13. An analytical solubility model for nitrogen-methane-ethane ternary mixtures (United States)

    Hartwig, Jason; Meyerhofer, Peter; Lorenz, Ralph; Lemmon, Eric


    Saturn's moon Titan has surface liquids of liquid hydrocarbons and a thick, cold, nitrogen atmosphere, and is a target for future exploration. Critical to the design and operation of vehicles for this environment is knowledge of the amount of dissolved nitrogen gas within the cryogenic liquid methane and ethane seas. This paper rigorously reviews experimental data on the vapor-liquid equilibrium of nitrogen/methane/ethane mixtures, noting the possibility for split liquid phases, and presents simple analytical models for conveniently predicting solubility of nitrogen in pure liquid ethane, pure liquid methane, and a mixture of liquid ethane and methane. Model coefficients are fit to three temperature ranges near the critical point, intermediate range, and near the freezing point to permit accurate predictions across the full range of thermodynamic conditions. The models are validated against the consolidated database of 2356 experimental data points, with mean absolute error between data and model less than 8% for both binary nitrogen/methane and nitrogen/ethane systems, and less than 17% for the ternary nitrogen/methane/ethane system. The model can be used to predict the mole fractions of ethane, methane, and nitrogen as a function of location within the Titan seas.

  14. Pressure transducers for cryogenic liquids

    Directory of Open Access Journals (Sweden)

    Pavlovskyy I. V.


    Full Text Available The developed universal construction of tensoresistive pressure transducer for cryogenic liquids (liquid nitrogen and liquid helium is described. The study of strain gauges characteristics on the basis of p-type Si whiskers with different boron concentration, mounted on the invar spring elements (beams, in the wide ranges of strain ε=±1,2·10-3 and temperature 4,2-300 К for transducers simulation were carried out. It was shown that using heavily doped silicon strain gages gives the possibility to develop pressure transducers for liquid nitrogen and liquid helium based on the classic piezoresistance. The significant increasing of the pressure transducers sensitivity for liquid helium could be achieved by using the strain gages on the basis of silicon with boron concentration in the vicinity of metal-insulator transition based on the non-classic piezoresitance. Developed pressure transducers for cryogenic liquids with strain gauges on the basis of doped p-type Si whiskers are presented.

  15. Fermi liquids and Luttinger liquids


    Schulz, H. J.; Cuniberti, G.; Pieri, P.


    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...

  16. Analysis of Screen Channel LAD Bubble Point Tests in Liquid Oxygen at Elevated Temperature (United States)

    Hartwig, Jason; McQuillen, John


    The purpose of this paper is to examine the key parameters that affect the bubble point pressure for screen channel Liquid Acquisition Devices in cryogenic liquid oxygen at elevated pressures and temperatures. An in depth analysis of the effect of varying temperature, pressure, and pressurization gas on bubble point is presented. Testing of a 200 x 1400 and 325 x 2300 Dutch Twill screen sample was conducted in the Cryogenics Components Lab 7 facility at the NASA Glenn Research Center in Cleveland, Ohio. Test conditions ranged from 92 to 130K and 0.138 - 1.79 MPa. Bubble point is shown to be a strong function of temperature with a secondary dependence on pressure. The pressure dependence is believed to be a function of the amount of evaporation and condensation occurring at the screen. Good agreement exists between data and theory for normally saturated liquid but the model generally under predicts the bubble point in subcooled liquid. Better correlation with the data is obtained by using the liquid temperature at the screen to determine surface tension of the fluid, as opposed to the bulk liquid temperature.

  17. The Heat and Mass Transfer Processes at the Cooling of Strong Heated Sphere in a Cold Liquid (United States)

    Puzina, Yu Yu


    Some new experimental results of continuum mechanics problems in two-phase systems are described. The processes of heat and mass transfer during cooling of strong heated sphere in the subcooled liquid are studied. Due to high level of heater temperature the stable vapor film is formed on the sphere surface. Calculation of steady-state transport processes at vapor – water interface is carried out using methods of molecular-kinetic theory. Heat transfer in vapor by thermal conductivity and natural convection in liquid are considered. Pressure balance is provided by hydrostatic pressure and non-equilibrium boundary condition. The results of the calculations are analyzed by comparison with previous data and experimental results.

  18. Electrochemical Stripping to Recover Nitrogen from Source-Separated Urine. (United States)

    Tarpeh, William A; Barazesh, James M; Cath, Tzahi Y; Nelson, Kara L


    Recovering nitrogen from separately collected urine can potentially reduce costs and energy of wastewater nitrogen removal and fertilizer production. Through benchtop experiments, we demonstrate the recovery of nitrogen from urine as ammonium sulfate using electrochemical stripping, a combination of electrodialysis and membrane stripping. Nitrogen was selectively recovered with 93% efficiency in batch experiments with real urine and required 30.6 MJ kg N-1 in continuous-flow experiments (slightly less than conventional ammonia stripping). The effects of solution chemistry on nitrogen flux, electrolytic reactions, and reactions with electro-generated oxidants were evaluated using synthetic urine solutions. Fates of urine-relevant trace organic contaminants, including electrochemical oxidation and reaction with electro-generated chlorine, were investigated with a suite of common pharmaceuticals. Trace organics (fertilizer product. This novel approach holds promise for selective recovery of nitrogen from concentrated liquid waste streams such as source-separated urine.

  19. The Ability of Kayambang (Salvinia molesta D.S Mitchell and EcEng Gondok (Eichornis crassipies (Mart. Solms to Decrease the Nitrogen Degree of liquid Waste from PTPN XIII Palm Oil factory in Ngabang-West Kalimantan

    Directory of Open Access Journals (Sweden)

    Agus Sri Mulyono


    Full Text Available The wastewater effluent of Ngabang Palm Oil Industry in one of several industrial waste, that contains high organic substances. One of them is nitrogen (N-total. Waste water treatment of palm oil industry used ponding system today, and one of solution to treat that wastewater effluent is using aquatic weeds as biofilter action. Water hyacinth (Eichornia crassipes (Mart. Solms and water fern (Salvinia molesta D.S.Mitchell known as aquatic weeds that capable to decrease in a large amount the organic and inorganic substances. The aim of this research is to study the capacity of water hyacinth and water fern in decreasing nitrogen compounds (N-total, ammonia, nitrate, nitrite, N-organic in wastewater effluent palm oil industry based in variation of treatment and difference of exposure time. This research was carried out in green house and Biology Laboratory of Biology Programme Study, Mathematic and Science Faculty of Tanjungpura University and Testing Laboratory of Institute for Industrial Research And Standardization Pontianak, from July 1st – October 31th, 2006. This experiment was designed in Completely Randomized Factorial Design with three treatments and three replication times. The collected data analized by Annava Test and least Significance Difference (LSD test. The result show that the treatment with combination of water hyacinth and water fern were able to decrease the N-total (92,64%; ammonia (96,47%; and nitrite (90,14%.

  20. Biofilm formation enables free-living nitrogen-fixing rhizobacteria to fix nitrogen under aerobic conditions. (United States)

    Wang, Di; Xu, Anming; Elmerich, Claudine; Ma, Luyan Z


    The multicellular communities of microorganisms known as biofilms are of high significance in agricultural setting, yet it is largely unknown about the biofilm formed by nitrogen-fixing bacteria. Here we report the biofilm formation by Pseudomonas stutzeri A1501, a free-living rhizospheric bacterium, capable of fixing nitrogen under microaerobic and nitrogen-limiting conditions. P. stutzeri A1501 tended to form biofilm in minimal media, especially under nitrogen depletion condition. Under such growth condition, the biofilms formed at the air-liquid interface (termed as pellicles) and the colony biofilms on agar plates exhibited nitrogenase activity in air. The two kinds of biofilms both contained large ovoid shape 'cells' that were multiple living bacteria embedded in a sac of extracellular polymeric substances (EPSs). We proposed to name such large 'cells' as A1501 cyst. Our results suggest that the EPS, especially exopolysaccharides enabled the encased bacteria to fix nitrogen while grown under aerobic condition. The formation of A1501 cysts was reversible in response to the changes of carbon or nitrogen source status. A1501 cyst formation depended on nitrogen-limiting signaling and the presence of sufficient carbon sources, yet was independent of an active nitrogenase. The pellicles formed by Azospirillum brasilense, another free-living nitrogen-fixing rhizobacterium, which also exhibited nitrogenase activity and contained the large EPS-encapsuled A1501 cyst-like 'cells'. Our data imply that free-living nitrogen-fixing bacteria could convert the easy-used carbon sources to exopolysaccharides in order to enable nitrogen fixation in a natural aerobic environment.

  1. Towards an interpretation of the mechanism of the actinides(III)/lanthanides(III) separation by synergistic solvent extraction with nitrogen-containing polydendate ligands; Vers une interpretation des mecanismes de la separation actinides(III)/lanthanides(III) par extraction liquide-liquide synergique impliquant des ligands polyazotes

    Energy Technology Data Exchange (ETDEWEB)

    Francois, N. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification, (DRRV), 30 - Marcoule (France); Universite Henri Poincare, 54 - Vandoeuvre-les-Nancy (France)


    In the field of the separation of long-lived radionuclides from the wastes produced by nuclear fuel reprocessing, aromatic nitrogen-containing polydendate ligands are potential candidates for the selective extraction, alone or in synergistic mixture with acidic extractants, of trivalent actinides from trivalent lanthanides. The first part of this work deals with the complexation of trivalent f cations with various nitrogen-containing ligands (poly-pyridine analogues). Time-resolved laser-induced fluorimetry (TRLIF) and UV-visible spectrophotometry were used to determine the nature and evaluate the stability of each complex. Among the ligands studied, the least basic Me-Btp proved to be highly selective towards americium(III) in acidic solution. In the second part, two synergistic systems (nitrogen-containing polydendate ligand and lipophilic carboxylic acid) are studied and compared in regard to the extraction and separation of lanthanides(III) and actinides(III). TRLIF and gamma spectrometry allowed the nature of the extracted complexes and the optimal conditions of efficiency of both systems to be determined. Comparison between these different studies showed that the selectivity of complexation of trivalent f cations by a given nitrogen-containing polydendate ligand could not always be linked to the Am(III)Eu(III) selectivity reached in synergistic extraction. The latter depends on the 'balance' between the acid-basic properties on the one hand, and on the hard-soft characteristics on the other hand, of both components of synergistic system. (author)

  2. Low Friction Cryostat for HTS Power Cable of Dutch Project

    DEFF Research Database (Denmark)

    Chevtchenko, Oleg; Zuijderduin, Roy; Smit, Johan


    . A flexible dummy HTS cable was inserted into this cryostat and sub-cooled liquid nitrogen was circulated in the annulus between the dummy cable surface and the inner cryostat surface. In the paper details are presented of the cryostat, of the measurement setup, of the experiment and of the results....

  3. Vacuum-cooled liquid nitrogen increases the developmental ability of vitrified-warmed bovine oocytes Nitrogênio super resfriado por vácuo melhora a capacidade de desenvolvimento de oócitos bovinos após vitrificação

    Directory of Open Access Journals (Sweden)

    Rodrigo Marques dos Santos


    Full Text Available The objective of this study was to determine the effects of vacuum-cooled liquid nitrogen on the development of vitrified immature (germinal vesicle stage; GV and mature (metaphase II; MII bovine oocytes after re-warming. Liquid nitrogen was exposed to either atmospheric pressure or to a vacuum (300mm Hg for 45sec; the latter decreased the temperature of the liquid nitrogen to -200°C. Partially denuded oocytes were vitrified either just after selection (GV or after 22 hours of in vitro maturation (MII in TCM 199 medium + 10% of estrous mare serum. For vitrification, oocytes were firstly exposed to an intermediate solution (10% EG + 10% DMSO for 30sec, followed by the vitrification solution (20% EG + 20% DMSO + 0.5M sucrose for 20sec. Groups of three or four oocytes were loaded into an open-pulled-straw and directly plunged into liquid nitrogen. Oocytes were subsequently re-warmed by exposure to air (25°C for 4sec, followed by 5 min exposure to decreasing concentrations (0.3 and 0.15M of sucrose. Fertilization (Day 0 was done with 2 x 106 spermatozoa mL-1 (selected by a swim-up procedure and incubated for 18 to 22 hours. Presumptive zygotes were cultured at 39°C in four-well dishes with SOFaaci medium, under 5% CO2 and saturated humidity. Cleavage (Day 2 and blastocyst rates (Day 8 were 33.9 and 4.2%, respectively, for GV stage oocytes at atmospheric pressure, 41.2 and 8.8% for GV oocytes under vacuum, 43.5 and 6.7% for MII oocytes at atmospheric pressure, and 53.6 and 10.6% for MII oocytes under vacuum. In conclusion, vacuum-cooled liquid nitrogen improved developmental rates of vitrified-thawed bovine oocytes.O objetivo deste estudo foi determinar o efeito do nitrogênio liquido super resfriado por vácuo no desenvolvimento, após reaquecimento, de oócitos bovinos vitrificados imaturos ou maturados. O nitrogênio líquido foi mantido em atmosfera normal ou submetido ao vácuo (300mm Hg por 45s este último reduzindo a temperatura do nitrog

  4. Subsidizing Liquidity

    DEFF Research Database (Denmark)

    Malinova, Katya; Park, Andreas


    Facing increased competition over the last decade, many stock exchanges changed their trading fees to maker-taker pricing, an incentive scheme that rewards liquidity suppliers and charges liquidity demanders. Using a change in trading fees on the Toronto Stock Exchange, we study whether and why...... the breakdown of trading fees between liquidity demanders and suppliers matters. Posted quotes adjust after the change in fee composition, but the transaction costs for liquidity demanders remain unaffected once fees are taken into account. However, as posted bid-ask spreads decline, traders (particularly...... retail) use aggressive orders more frequently, and adverse selection costs decrease....

  5. The nitrogen cycle

    National Research Council Canada - National Science Library

    Stein, Lisa Y; Klotz, Martin G


    .... Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions...

  6. Toward nitrogen neutral biofuel production. (United States)

    Huo, Yi-Xin; Wernick, David G; Liao, James C


    Environmental concerns and an increasing global energy demand have spurred scientific research and political action to deliver large-scale production of liquid biofuels. Current biofuel processes and developing approaches have focused on closing the carbon cycle by biological fixation of atmospheric carbon dioxide and conversion of biomass to fuels. To date, these processes have relied on fertilizer produced by the energy-intensive Haber-Bosch process, and have not addressed the global nitrogen cycle and its environmental implications. Recent developments to convert protein to fuel and ammonia may begin to address these problems. In this scheme, recycling ammonia to either plant or algal feedstocks reduces the demand for synthetic fertilizer supplementation. Further development of this technology will realize its advantages of high carbon fixation rates, inexpensive and simple feedstock processing, in addition to reduced fertilizer requirements. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Condensation of acetol and acetic acid vapor with sprayed liquid (United States)

    A cellulose-derived fraction of biomass pyrolysis vapor was simulated by evaporating acetol and acetic acid (AA) from flasks on a hot plate. The liquid in the flasks was infused with heated nitrogen. The vapor/nitrogen stream was superheated in a tube oven and condensed by contact with a cloud of ...

  8. Update: Biological Nitrogen Fixation. (United States)

    Wiseman, Alan; And Others


    Updates knowledge on nitrogen fixation, indicating that investigation of free-living nitrogen-fixing organisms is proving useful in understanding bacterial partners and is expected to lead to development of more effective symbioses. Specific areas considered include biochemistry/genetics, synthesis control, proteins and enzymes, symbiotic systems,…

  9. Nitrogen trading tool (United States)

    The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

  10. Soybean Nitrogen Fixing Attributes

    African Journals Online (AJOL)

    reproductive unit and nitrogen fixing attributes (Carruthers er. al., 2000). In combination with various lupin and forages, these authors showed that soybean grain yield was decreased by most treatments. In order to limit over population and pollution risks, low nitrogen fertilizer agricultural systems are likely to be advocated.

  11. Nitrogen use efficiency (NUE)

    NARCIS (Netherlands)

    Oenema, O.


    There is a need for communications about resource use efficiency and for measures to increase the use efficiency of nutrients in relation to food production. This holds especially for nitrogen. Nitrogen (N) is essential for life and a main nutrient element. It is needed in relatively large

  12. Surface Instability of Liquid Propellant under Vertical Oscillatory Forcing (United States)

    Yang, H. Q.; Peugeot, John


    Fluid motion in a fuel tank produced during thrust oscillations can circulate sub-cooled hydrogen near the liquid-vapor interface resulting in increased condensation and ullage pressure collapse. The first objective of this study is to validate the capabilities of a Computational Fluid Dynamics (CFD) tool, CFD-ACE+, in modeling the fundamental interface transition physics occurring at the propellant surface. The second objective is to use the tool to assess the effects of thrust oscillations on surface dynamics. Our technical approach is to first verify the CFD code against known theoretical solutions, and then validate against existing experiments for small scale tanks and a range of transition regimes. A 2D axisymmetric, multi-phase model of gases, liquids, and solids is used to verify that CFD-ACE+ is capable of modeling fluid-structure interaction and system resonance in a typical thrust oscillation environment. Then, the 3D mode is studied with an assumed oscillatory body force to simulate the thrust oscillating effect. The study showed that CFD modeling can capture all of the transition physics from solid body motion to standing surface wave and to droplet ejection from liquid-gas interface. Unlike the analytical solutions established during the 1960 s, CFD modeling is not limited to the small amplitude regime. It can extend solutions to the nonlinear regime to determine the amplitude of surface waves after the onset of instability. The present simulation also demonstrated consistent trends from numerical experiments through variation of physical properties from low viscous fluid to high viscous fluids, and through variation of geometry and input forcing functions. A comparison of surface wave patterns under various forcing frequencies and amplitudes showed good agreement with experimental observations. It is concluded that thrust oscillations can cause droplet formation at the interface, which results in increased surface area and enhanced heat transfer

  13. Changes in morphology of long bone marrow tissue of rats submitted to cryotherapy with liquid nitrogen Alterações na morfologia do tecido medular de ossos longos de ratos submetido à crioterapia com nitrogênio líquido

    Directory of Open Access Journals (Sweden)

    Fábio Wildson Gurgel Costa


    Full Text Available PURPOSE: To study the main effects of local use of liquid nitrogen on bone marrow tissue in rats. METHODS: The femoral diaphyses of 42 Wistar rats were exposed to three local and sequential applications of liquid nitrogen for one or two minutes, intercalated with periods of five minutes of passive thawing. The animals were sacrificed after one, two, four and 12 weeks and the specimens obtained were analyzed histomorphologically. RESULTS: In the second experimental week of one-minute protocol, histological degree of inflammation obtained a mean score of one (mild, ranging from 0 (absent or scarce and two (moderate (Kruskal-Wallis test p=0.01. In the second experimental week of two-minute protocol, degree of inflammation to the medullar tissue obtained an average score of two (Kruskal-Wallis test p=0.01. CONCLUSION: The degree of inflammation of the bone marrow tissue was higher in protocol of three applications of two minutes compared to protocol of three applications of one minute.OBJETIVO: Investigar os principais efeitos do uso local de nitrogênio líquido sobre o tecido medular ósseo em ratos. MÉTODOS: As diáfises femorais de 42 ratos Wistar foram expostas a três aplicações sequenciais locais de nitrogênio líquido por um ou dois minutos, intercaladas por períodos de cinco minutos de degelo espontâneo. Os animais foram sacrificados após uma, duas, quatro e 12 semanas e os espécimes obtidos foram analisados histomorfologicamente. RESULTADOS: Na segunda semana experimental do protocolo de um minuto, o grau histológico de inflamação obteve um escore médio de um (leve variando entre 0 (ausente ou escarço a dois (moderado (Teste de Kruskal-Wallis p=0.01. Na segunda semana experimental do protocolo de dois minutos, o grau histológico de inflamação do tecido medular obteve um escore máximo de dois (moderado (Teste de Kruskal-Wallis p=0.01. CONCLUSÃO: O grau de inflamação do tecido medular ósseo foi maior no protocolo de tr

  14. Rupture of a Locally Heated Liquid Film Driven by the Shear Stress of Gas and Gravity (United States)

    Zaitsev, D. V.; Kabob, O. A.


    The paper focuses on the recent progress that has been achieved by the authors through conducting experiments with locally heated shear-driven and falling liquid films. Rupture of the liquid film was investigated and it was found that scenario of film rupture differs widely for different flow regimes. The critical heat flux is about 10 times higher for a shear driven film than that for a falling liquid film, and reaches 250 W/cm2 in experiments with water at atmospheric pressure. Rupture of a subcooled falling liquid film heated from the substrate is preceded by the formation of steady state film surface deformations. The film spontaneously ruptures at the moment when the film thickness in the thinned region reaches a certain critical minimum independent of both the Reynolds number and the plate inclination angle (gravity force). By means of high speed imaging it is found that the process of rupture involves two stages: 1) abrupt film thinning down to a thin residual film; 2) rupture and dryout of the residual film. As the plate inclination angle is reduced the threshold heat flux required for film rupture weakly decreases, however when the angle becomes negative the threshold heat flux begins to rise dramatically, which is associated with an increase of the stabilizing hydrostatic effect due to the growth of the film thickness.

  15. Managing liquidity

    DEFF Research Database (Denmark)

    Pokutta, Sebastian; Schmaltz, Christian


    Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de-)centraliza......Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de......-)centralization. We provide an analytical solution for the 2-branch model and show that a liquidity center can be interpreted as an option on immediate liquidity. Therefore, its value can be interpreted as the price of information, i.e., the price of knowing the exact demand. Furthermore, we derive the threshold...... above which it is advantageous to open a liquidity center and show that it is a function of the volatility and the characteristic of the bank network. Finally, we discuss the n-branch model for real-world banking groups (10-60 branches) and show that it can be solved with high granularity (100 scenarios...

  16. The nitrogen cycle. (United States)

    Stein, Lisa Y; Klotz, Martin G


    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Liquid explosives

    CERN Document Server

    Liu, Jiping


    The book drawing on the author's nearly half a century of energetic materials research experience intends to systematically review the global researches on liquid explosives. The book focuses on the study of the conception, explosion mechanism, properties and preparation of liquid explosives. It provides a combination of theoretical knowledge and practical examples in a reader-friendly style. The book is likely to be interest of university researchers and graduate students in the fields of energetic materials, blasting engineering and mining.

  18. Capillary GC Detection Methods for Nitrogen and Sulfur Compounds in Shale-Derived Jet Propulsion Fuels. (United States)


    products, tar sand bitumen ), the interest in this area has grown. Several correlations have been drawn between nitrogen and sulfur contents in fuels and...poor fuel performance. Tar sand bitumens , shale oils and coal-derived liquids contain large amounts of sulfur and nitrogen compounds. Emissions from...GC detector (16). The fused silica capillary column enters the pyrolysis tube of the nitrogen analyzer from the GC oven through a heated transfer line

  19. Mineralization of Nitrogen in Hydromorphic Soils Amended with ...

    African Journals Online (AJOL)

    Michael Horsfall

    drying the sludge was spread on plastic tray 30 x 50 cm placed in well-ventilated hood. A fan was directed towards the hood to enhance evaporation of the liquid. ..... Agric. Wastes. 18:175-195. Christenen BT; Olesen JE 1998. Nitrogen mineralization potential organic mineral size separated from soils with annual straw.

  20. Effect of nitrogen concentration of urea ammonium nitrate, and ...

    African Journals Online (AJOL)

    Liquid urea ammonium nitrate (UAN) was applied to dryland Pennisetum clandestinum (Kikuyu (Chiov)) and Cynodon hybrid (Coastcross II (L.) (Pers.)) pastures at two levels (207 and 414 kg N/ha/season) and at three concentrations (10, 5; 21 and 42% N) of nitrogen. The degree of leaf scorch increased as both the amount ...

  1. Nitrogen supplements effect on amylase production by Aspergillus ...

    African Journals Online (AJOL)

    The production of amylase by Aspergillus niger on three cassava whey media in liquid shake culture was compared. The supplemented cassava whey (SCW) medium exhibited gave amylase activity of 495 U/ml. Biomass cropped was 1.63 g/l in the SCW medium. Yeast extract employed as a nitrogen supplement increased ...

  2. Utilisation of organic and inorganic nitrogen sources by ...

    African Journals Online (AJOL)

    The ability of Scleroderma sinnamariense Mont. to utilise some organic and inorganic nitrogen (N) sources for growth was examined in axenic liquid cultures. Pisolithus tinctorius Pers. was included for comparison. Both fungi species produced measurable biomass on all the N sources used in this experiment. The growth of ...

  3. Urea nitrogen urine test (United States)

    ... levels usually indicate: Increased protein breakdown in the body Too much protein intake Risks There are no risks with this test. Alternative Names Urine urea nitrogen Images Female urinary tract Male urinary tract References Agarwal R. Approach to the ...

  4. Mineral commodity profiles: nitrogen (United States)

    Kramer, Deborah A.


    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  5. Commercial Nitrogen Fertilizer Purchased (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer nitrogen (N) purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year...

  6. Protein Nitrogen Determination (United States)

    Nielsen, S. Suzanne

    The protein content of foods can be determined by numerous methods. The Kjeldahl method and the nitrogen combustion (Dumas) method for protein analysis are based on nitrogen determination. Both methods are official for the purposes of nutrition labeling of foods. While the Kjeldahl method has been used widely for over a hundred years, the recent availability of automated instrumentation for the Dumas method in many cases is replacing use of the Kjeldahl method.

  7. Brucella, nitrogen and virulence. (United States)

    Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques


    The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

  8. Nitrogen Uptake in Spinach (United States)

    Ramirez, J.; VanBenthem, P.


    A plant's absorption of nitrogen can be encouraged by a variety of environmental factors, especially the application of fertilizers. As a common limiting factor in plant growth, not up taking enough nitrogen can be a result of an unhealthy plant. Moreover, as farmers seek out methods to increase growth of plants, fertilizers are used as a solution to the issue of nitrogen deficiency to incorporate additional nitrogen from chemical or organic sources, by not using the right fertilizer can greatly affect the plats. The point of this research project is to determine the effect of various fertilizers on the plant growth, and to correlate the measured nitrogen, water and chlorophyll content in spinach leaves. Spinach leaves were used because they are known to quickly uptake chemicals in the environment. The spinach plants were exposed to four different growing parameters, which are referred to as control, ammonium nitrate, MiracleGro , and organic. The spinach was originally placed in nitrogen deficient soil with only 2.2x10 4 weight percent (wt. %) nitrogen. The leaves in the control group were grown in this nitrogen deficient soil without any fertilizer added. Ammomium nitrate and MiracleGro were added to the spinach in the A and MG groups, respectively, and organic chicken stool was used for the O group. By using a spectral imaging system and flame combustion techniques, the chlorophyll content can be related to the nitrogen content in the spinach leaves. In these spinach leaves, nitrogen and chlorophyll content were measured, chlorophyll is a green pigment that plays a crucial role in producing nutrients for green plants. The lack of chlorophyll will allow the plant to become susceptible to diseases, so it is extremely important that the plants have a high content of chlorophyll. The role of nitrogen in chlorophyll is very important and helps in the creation of chlorophyll; therefore it is necessary that an appropriate amount of nitrogen is added for optimal growth

  9. Liquid Crystals (United States)


    Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.

  10. The processes of vaporization in the porous structures working with the excess of liquid

    Directory of Open Access Journals (Sweden)

    Genbach Alexander A.


    Full Text Available The processes of vaporization in porous structures, working with the excess of liquid are investigated. With regard to the thermal power plants new porous cooling system is proposed and investigated, in which the supply of coolant is conducted by the combined action of gravity and capillary forces. The cooling surface is made of stainless steel, brass, copper, bronze, nickel, alundum and glass, with wall thickness of (0.05-2•10-3 m. Visualizations of the processes of vaporization were carried out using holographic interferometry with the laser system and high speed camera. The operating conditions of the experiments were: water pressures (0.01-10 MPa, the temperature difference of sub-cooling (0-20°C, an excess of liquid (1-14 of the steam flow, the heat load (1-60•104 W/m2, the temperature difference (1-60°C and orientation of the system (± 0 - ± 90 degrees. Studies have revealed three areas of liquid vaporization process (transitional, developed and crisis. The impact of operating and design parameters on the integrated and thermal hydraulic characteristics was defined. The optimum (minimum flow rate of cooling fluid and the most effective type of mesh porous structure were also defined.

  11. Catalytic combustion of coal-derived liquids (United States)

    Bulzan, D. L.; Tacina, R. R.


    A noble metal catalytic reactor was tested with three grades of SRC 2 coal derived liquids, naphtha, middle distillate, and a blend of three parts middle distillate to one part heavy distillate. A petroleum derived number 2 diesel fuel was also tested to provide a direct comparison. The catalytic reactor was tested at inlet temperatures from 600 to 800 K, reference velocities from 10 to 20 m/s, lean fuel air ratios, and a pressure of 3 x 10 to the 5th power Pa. Compared to the diesel, the naphtha gave slightly better combustion efficiency, the middle distillate was almost identical, and the middle heavy blend was slightly poorer. The coal derived liquid fuels contained from 0.58 to 0.95 percent nitrogen by weight. Conversion of fuel nitrogen to NOx was approximately 75 percent for all three grades of the coal derived liquids.

  12. Transformations of Liquid Metals in Ionic Liquid


    Liu, Fujun; Yu, Yongze; Liu, Jing


    Experimental studies were carried out on the motions and transformations of liquid metal in ionic liquid under applied electric field. The induced vortex rings and flows of ionic liquid were determined via the photographs taken sequentially over the experiments. The polarization of electric double layer of liquid metals was employed to explain the flow of ionic liquid with the presence of liquid metal. Unlike former observation of liquid metal machine in conventional solution, no gas bubble w...

  13. Cryogenic System for the Test Facilities of the ATLAS Liquid Argon Calorimeter Modules

    CERN Document Server

    Bremer, J; Chalifour, M; Haug, F; Passardi, Giorgio; Tischhauser, Johann


    To perform cold tests on the different modules of the ATLAS liquid argon calorimeter, a cryogenic system has been constructed and is now operated at the CERN North Experimental Area. Three different test cryostats will house the modules, which can also be exposed to particle beams for calibration purposes. The three cryostats share a common liquid argon and liquid nitrogen distribution system. The system is rather complex since it has to allow operations of the three cryostats at the same time. Liquid nitrogen is used as cold source for both the cool-down of the cryostats and for normal operation of the cryostats filled with liquid argon.

  14. Thermocapillary convection around gas bubbles: an important natural effect for the enhancement of heat transfer in liquids under microgravity. (United States)

    Betz, J; Straub, J


    In the presence of a temperature gradient at a liquid-gas or liquid-liquid interface, thermocapillary or Marangoni convection develops. This convection is a special type of natural convection that was not paid much attention in heat transfer for a long time, although it is strong enough to drive liquids against the direction of buoyancy on Earth. In a microgravity environment, however, it is the remaining mode of natural convection and supports heat and mass transfer. During boiling in microgravity it was observed at subcooled liquid conditions. Therefore, the question arises about its contribution to heat transfer without phase change. Thermocapillary convection was quantitatively studied at single gas bubbles in various liquids, both experimentally and numerically. A two-dimensional mathematical model described in this article was developed. The coupled mechanism of heat transfer and fluid flow in pure liquids around a single gas bubble was simulated with a control-volume FE-method. The simulation was accompanied and compared with experiments on Earth. The numerical results are in good accordance with the experiments performed on Earth at various Marangoni numbers using various alcohols of varying chain length and Prandtl numbers. As well as calculations on Earth, the numerical method also allows simulations at stationary spherical gas bubbles in a microgravity environment. The results demonstrate that thermocapillary convection is a natural heat transfer mechanism that can partially replace the buoyancy in a microgravity environment, if extreme precautions are taken concerning the purity of the liquids, because impurities accumulate predominantly at the interface. Under Earth conditions, an enhancement of the heat transfer in a liquid volume is even found in the case where thermocapillary flow is counteracted by buoyancy. In particular, the obstructing influence of surface active substances could be observed during the experiments on Earth in water and also in

  15. CdZnTe room-temperature semiconductor operation in liquid scintillator

    CERN Document Server

    Stewart, D Y


    We demonstrate the first operation of CdZnTe room-temperature detectors in a liquid scintillator environment. This work follows conceptually the Heusser-type detector method of operating HPGe detectors in liquid nitrogen and liquid argon but instead for a far more practical room-temperature ensemble with the aim of achieving ultra-low background levels for radiation detection.

  16. A microfluidic study of liquid-liquid extraction mediated by carbon dioxide. (United States)

    Lestari, Gabriella; Salari, Alinaghi; Abolhasani, Milad; Kumacheva, Eugenia


    Liquid-liquid extraction is an important separation and purification method; however, it faces a challenge in reducing the energy consumption and the environmental impact of solvent (extractant) recovery. The reversible chemical reactions of switchable solvents (nitrogenous bases) with carbon dioxide (CO2) can be implemented in reactive liquid-liquid extraction to significantly reduce the cost and energy requirements of solvent recovery. The development of new effective switchable solvents reacting with CO2 and the optimization of extraction conditions rely on the ability to evaluate and screen the performance of switchable solvents in extraction processes. We report a microfluidic strategy for time- and labour-efficient studies of CO2-mediated solvent extraction. The platform utilizes a liquid segment containing an aqueous extractant droplet and a droplet of a solution of a switchable solvent in a non-polar liquid, with gaseous CO2 supplied to the segment from both sides. Following the reaction of the switchable solvent with CO2, the solvent becomes hydrophilic and transfers from the non-polar solvent to the aqueous droplet. By monitoring the time-dependent variation in droplet volumes, we determined the efficiency and extraction time for the CO2-mediated extraction of different nitrogenous bases in a broad experimental parameter space. The platform enables a significant reduction in the amount of switchable solvents used in these studies, provides accurate temporal characterization of the liquid-liquid extraction process, and offers the capability of high-throughput screening of switchable solvents.

  17. Liquid Marbles

    KAUST Repository

    Khalil, Kareem


    Granulation, the process of formation of granules from a combination of base powders and binder liquids, has been a subject of research for almost 50 years, studied extensively for its vast applications, primarily to the pharmaceutical industry sector. The principal aim of granulation is to form granules comprised of the active pharmaceutical ingredients (API’s), which have more desirable handling and flowability properties than raw powders. It is also essential to ensure an even distribution of active ingredients within a tablet with the goal of achieving time‐controlled release of drugs. Due to the product‐specific nature of the industry, however, data is largely empirical [1]. For example, the raw powders used can vary in size by two orders of magnitude with narrow or broad size distributions. The physical properties of the binder liquids can also vary significantly depending on the powder properties and required granule size. Some significant progress has been made to better our understanding of the overall granulation process [1] and it is widely accepted that the initial nucleation / wetting stage, when the binder liquid first wets the powders, is key to the whole process. As such, many experimental studies have been conducted in attempt to elucidate the physics of this first stage [1], with two main mechanisms being observed – classified by Ivenson [1] as the “Traditional description” and the “Modern Approach”. See Figure 1 for a graphical definition of these two mechanisms. Recent studies have focused on the latter approach [1] and a new, exciting development in this field is the Liquid Marble. This interesting formation occurs when a liquid droplet interacts with a hydrophobic (or superhydrophobic) powder. The droplet can become encased in the powder, which essentially provides a protective “shell” or “jacket” for the liquid inside [2]. The liquid inside is then isolated from contact with other solids or liquids and has some

  18. Fiber-Optic Continuous Liquid Sensor for Cryogenic Propellant Gauging (United States)

    Xu. Wei


    An innovative fiber-optic sensor has been developed for low-thrust-level settled mass gauging with measurement uncertainty sensor uses a single optical fiber to measure liquid level and liquid distribution of cryogenic propellants. Every point of the sensing fiber is a point sensor that not only distinguishes liquid and vapor, but also measures temperature. This sensor is able to determine the physical location of each point sensor with 1-mm spatial resolution. Acting as a continuous array of numerous liquid/vapor point sensors, the truly distributed optical sensing fiber can be installed in a propellant tank in the same manner as silicon diode point sensor stripes using only a single feedthrough to connect to an optical signal interrogation unit outside the tank. Either water or liquid nitrogen levels can be measured within 1-mm spatial resolution up to a distance of 70 meters from the optical interrogation unit. This liquid-level sensing technique was also compared to the pressure gauge measurement technique in water and liquid nitrogen contained in a vertical copper pipe with a reasonable degree of accuracy. It has been demonstrated that the sensor can measure liquid levels in multiple containers containing water or liquid nitrogen with one signal interrogation unit. The liquid levels measured by the multiple fiber sensors were consistent with those virtually measured by a ruler. The sensing performance of various optical fibers has been measured, and has demonstrated that they can survive after immersion at cryogenic temperatures. The fiber strength in liquid nitrogen has also been measured. Multiple water level tests were also conducted under various actual and theoretical vibration conditions, and demonstrated that the signal-to-noise ratio under these vibration conditions, insofar as it affects measurement accuracy, is manageable and robust enough for a wide variety of spacecraft applications. A simple solution has been developed to absorb optical energy at

  19. The Global Nitrogen Story (United States)

    Galloway, J. N.


    In the absence of human activities, biotic nitrogen fixation is the primary source of reactive N to the environment. Over the last few decades, human activity has surpassed natural terrestrial nitrogen fixation rates by energy production (fossil fuel combustion) and food production (Haber-Bosch based fertilizer production and crop cultivation). An amount equivalent to over half of the anthropogenic N fixed each year is emitted to the atmosphere or discharged to rivers, for dispersion to environmental systems. An unknown amount of this anthropogenic N is accumulating in the environment resulting in a enhanced greenhouse effect, acid deposition, photochemical smog, stratospheric ozone depletion and eutrophication of fresh and marine waters. This paper will assess the state of knowledge on the global N cycle and present a context in which to place the impacts of humans on nitrogen cycling at regional scales.

  20. The nitrogen cycle: Atmosphere interactions (United States)

    Levine, J. S.


    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  1. Characterization of organic nitrogen in IBCSP coals. Final technical report, September 1, 1990--August 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Kruge, M.A.


    The overall objective of this study was to determine the content and distribution of organic nitrogen in a series of IBCSP coals and their isolated macerals. The specific objectives were: to determine the bulk nitrogen contents for coals, isolated macerals, oxidation products and residues, solvent extracts and their liquid chromatographic fractions, and pyrolyzates; to determine the distribution of organic nitrogen in all coal derivatives enumerated in Objective 1 which are Gas Chromatography (GC)-amenable. This will be accomplished by GC-Thermionic Specific Detectors; to determine the molecular structure of the major nitrogen compounds detected in Objective 2, using mass spectrometry.

  2. Desenvolvimento e avaliação de calorímetros por nitrogênio líquido e fluxo contínuo para medição de aporte térmico Development and assessment of calorimeters using liquid nitrogen and continuous flow (water for heat input measurement

    Directory of Open Access Journals (Sweden)

    Hernán Dario Hernández Arevalo


    ,6% para GMAW curto-circuito convencional, 73,6% para GMAW goticular e 76,1% para os processos GMAW curto circuito-controlado. Os resultados obtidos com o calorímetro de fluxo contínuo (água acompanharam a tendência do calorímetro de nitrogênio líquido, mas com resultados médios 12% abaixo.One of the most influent parameter on the welding process at both industrial and research levels is the heat delivered to the workpiece (heat input due to its direct connection with changes in metallurgical characteristics and mechanical properties of the weld joint. In order to quantify the heat input, different methods have been developed, both theoretical (analytical and numerical ones and experimental (calorimetry. These techniques present large dispersion of results for thermal efficiency of welding processes. Therefore, this work aims to present the project, construction and assessment of a liquid nitrogen calorimeter and other one based on constant flow (water measurement. Both calorimeters were evaluated for measuring heat input and thermal efficiency of GTAW and GMAW processes. For GTAW process, bead on plate welding was carried out with Ar as shielding gas over ASTM A36 plate, varying current, arc length, travel speed and bead length. For GMAW processes, both short-circuit and spray transfers were used with AWS ER70S-6 wire with 1.2 mm of diameter and Ar+25%CO2 (short-circuit and Ar+5%O2 (spray as shielding gases. For derivative processes (STT - Surface Tension Transfer, RMD - Regulated Metal Deposition, CMT - Cold Metal Transfer, GMAW-P - Pulsed and GMAW-VP - Variable Polarity, the welding parameters were adopted from previous researches from Laprosolda (Center for Research and Development of Welding Processes. It can be concluded that the liquid nitrogen calorimeter presents good repeatability and stability (maximum data scattering of 3%. Also, the obtained results are coherent for different welding conditions applied through the work with global thermal efficiencies

  3. Liquid/liquid heat exchanger (United States)

    Miller, C. G.


    Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

  4. Nitrogen Biobank for Cardiovascular Research (United States)

    Mercuri, Antonella; Turchi, Stefano; Borghini, Andrea; Chiesa, Maria Rosa; Lazzerini, Guido; Musacchio, Laura; Zirilli, Ottavio; Andreassi, Maria Grazia


    Biobanks play a crucial role in "-Omics" research providing well-annotated samples to study major diseases, their pathways and mechanisms. Accordingly, there are major efforts worldwide to professionalize biobanks in order to provide high quality preservation and storage of biological samples with potentially greater scientific impact. Biobanks are an important resource to elucidate relevant disease mechanisms as well as to improve the diagnosis, prognosis, and treatment of both pediatric and adult cardiovascular disease. High-quality biological sample collections housed in specialized bio-repositories are needed to discover new genetic factors and molecular mechanisms of congenital heart disease and inherited cardiomyopathies in order to prevent the potential risk of having a fatal cardiac condition as well as to facilitate rational drug design around molecular diseases (personalized medicine). Biological samples are also required to improve the understanding the environmental mechanisms of heart disease (environmental cardiology). The goal of this paper is to focus on preanalytical issues (informed consent, sample type, time of collection, temperature and processing procedure) related to collection of biological samples for research purposes. In addition, the paper provides an overview of the efforts made recently by our Institute in designing and implementing a high-security liquid nitrogen storage system (-196°C). We described the implementations of reliable preservation technologies and appropriate quality control (the right temperature, the right environment, fully traceable with all possible back-up systems) in order to ensure maximum security for personnel as well as the quality and suitability of the stored samples. PMID:23909635

  5. In-situ Monitoring of Sub-cooled Nucleate Boiling on Fuel Cladding Surface in Water at 1 bar and 130 bars using Acoustic Emission Method

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Seung Heon; Wu, Kaige; Shim, Hee-Sang; Lee, Deok Hyun; Hur, Do Haeng [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    Crud deposition increases through a sufficient corrosion product supply around the steam-liquid interface of a boiling bubble. Therefore, the understanding of this SNB phenomenon is important for effective and safe operation of nuclear plants. The experimental SNB studies have been performed in visible conditions at a low pressure using a high speed video camera. Meanwhile, an acoustic emission (AE) method is an on-line non-destructive evaluation method to sense transient elastic wave resulting from a rapid release of energy within a dynamic process. Some researchers have investigated boiling phenomena using the AE method. However, their works were performed at atmospheric pressure conditions. Therefore, the objective of this work is for the first time to detect and monitor SNB on fuel cladding surface in simulated PWR primary water at 325 .deg. C and 130 bars using an AE technique. We successfully observed the boiling AE signals in primary water at 1 bar and 130 bars using AE technique. Visualization test was performed effectively to identify a correlation between water boiling phenomenon and AE signals in a transparent glass cell at 1 bar, and the boiling AE signals were in good agreement with the boiling behavior. Based on the obtained correlations at 1 bar, the AE signals obtained at 130 bars were analyzed. The boiling density and size of the AE signals at 130 bars were decreased by the flow parameters. However, overall AE signals showed characteristics and a trend similar to the AE signals at 1 bar. This indicates that boiling AE signals are detected successfully at 130 bars, and the AE technique can be effectively implemented in non-visualized condition at high pressures.

  6. Nitrogen Trading Tool (NTT) (United States)

    The Natural Resources Conservation Service (NRCS) recently developed a prototype web-based nitrogen trading tool to facilitate water quality credit trading. The development team has worked closely with the Agriculture Research Service Soil Plant Nutrient Research Unit (ARS-SPNR) and the Environmenta...

  7. Aerogel Insulation Applications for Liquid Hydrogen Launch Vehicle Tanks (United States)

    Fesmire, J. E.; Sass, J.


    Aerogel based insulation systems for ambient pressure environments were developed for liquid hydrogen (LH2) tank applications. Solutions to thermal insulation problems were demonstrated for the Space Shuttle External Tank (ET) through extensive testing at the Cryogenics Test Laboratory. Demonstration testing was performed using a 1/10th scale ET LH2 intertank unit and liquid helium as the coolant to provide the 20 K cold boundary temperature. Cryopumping tests in the range of 20K were performed using both constant mass and constant pressure methods. Long-duration tests (up to 10 hours) showed that the nitrogen mass taken up inside the intertank is reduced by a factor of nearly three for the aerogel insulated case as compared to the un-insulated (bare metal flight configuration) case. Test results including thermal stabilization, heat transfer effectiveness, and cryopumping confirm that the aerogel system eliminates free liquid nitrogen within the intertank. Physisorption (or adsorption) of liquid nitrogen within the fine pore structure of aerogel materials was also investigated. Results of a mass uptake method show that the sorption ratio (liquid nitrogen to aerogel beads) is about 62 percent by volume. A novel liquid nitrogen production method of testing the liquid nitrogen physical adsorption capacity of aerogel beads was also performed to more closely approximate the actual launch vehicle cooldown and thermal stabilization effects within the aerogel material. The extraordinary insulating effectiveness of the aerogel material shows that cryopumping is not an open-cell mass transport issue but is strictly driven by thermal communication between warm and cold surfaces. The new aerogel insulation technology is useful to solve heat transfer problem areas and to augment existing thermal protection systems on launch vehicles. Examples are given and potential benefits for producing launch systems that are more reliable, robust, reusable, and efficient are outlined.

  8. Nitrogen availability for nitrogen fixing cyanobacteria upon growth ...

    African Journals Online (AJOL)

    The filamentous cyanobacterium Nostoc PCC 7120 is able to convert dinitrogen to ammonia in the absence of combined nitrogen. The expression of 20% of coding sequences from all major metabolic categories was examined in nitrogen fixing and non-nitrogen fixing growth conditions. The expression data were correlated ...

  9. Liquid helium

    CERN Document Server

    Atkins, K R


    Originally published in 1959 as part of the Cambridge Monographs on Physics series, this book addresses liquid helium from the dual perspectives of statistical mechanics and hydrodynamics. Atkins looks at both Helium Three and Helium Four, as well as the properties of a combination of the two isotopes. This book will be of value to anyone with an interest in the history of science and the study of one of the universe's most fundamental elements.

  10. The Global Nitrogen Cycle (United States)

    Galloway, J. N.


    Once upon a time nitrogen did not exist. Today it does. In the intervening time the universe was formed, nitrogen was created, the Earth came into existence, and its atmosphere and oceans were formed! In this analysis of the Earth's nitrogen cycle, I start with an overview of these important events relative to nitrogen and then move on to the more traditional analysis of the nitrogen cycle itself and the role of humans in its alteration.The universe is ˜15 Gyr old. Even after its formation, there was still a period when nitrogen did not exist. It took ˜300 thousand years after the big bang for the Universe to cool enough to create atoms; hydrogen and helium formed first. Nitrogen was formed in the stars through the process of nucleosynthesis. When a star's helium mass becomes great enough to reach the necessary pressure and temperature, helium begins to fuse into still heavier elements, including nitrogen.Approximately 10 Gyr elapsed before Earth was formed (˜4.5 Ga (billion years ago)) by the accumulation of pre-assembled materials in a multistage process. Assuming that N2 was the predominate nitrogen species in these materials and given that the temperature of space is -270 °C, N2 was probably a solid when the Earth was formed since its boiling point (b.p.) and melting point (m.p.) are -196 °C and -210 °C, respectively. Towards the end of the accumulation period, temperatures were probably high enough for significant melting of some of the accumulated material. The volcanic gases emitted by the resulting volcanism strongly influenced the surface environment. Nitrogen was converted from a solid to a gas and emitted as N2. Carbon and sulfur were probably emitted as CO and H2S (Holland, 1984). N2 is still the most common nitrogen volcanic gas emitted today at a rate of ˜2 TgN yr-1 (Jaffee, 1992).Once emitted, the gases either remained in the atmosphere or were deposited to the Earth's surface, thus continuing the process of biogeochemical cycling. The rate of

  11. Experimental investigation of quench and re-wetting temperatures of hot horizontal tubes well above the limiting temperature for solid–liquid contact

    Energy Technology Data Exchange (ETDEWEB)

    Takrouri, Kifah, E-mail: [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Luxat, John, E-mail: [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada); Hamed, Mohamed [Thermal Processing Laboratory (TPL), Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L7 (Canada)


    . The effects of initial surface temperature, water subcooling (in the range 15–80 °C) and jet velocity (in the range 0.15–1.60 m/s) on the quench process were investigated. The quench and the re-wetting temperature (the temperature at which the liquid establishes wet contact with the solid) were found to greatly depend on water subcooling. One of the main findings in this study is the existence of a critical water subcooling range within which any small change in water subcooling has a considerable effect on both the quench and the re-wetting temperatures. Empirical correlations have been developed and provided good fit of the experimental data and agreed well with correlations developed by other researchers for curved surfaces. The quench temperature was found to decrease by increasing surface curvature and solid thermal conductivity. However, the re-wetting temperature is a weak function of both variables. Effect of spatial location on the surface of the tube was also studied. The stagnation point showed higher quench and re-wetting temperatures compared to other locations on the tube surface.

  12. Avoiding the big bang : membrane nitrogen generation system provides safety and convenience

    Energy Technology Data Exchange (ETDEWEB)

    Ross, E.


    A shortage of liquid nitrogen prompted Lexington Energy Services Inc. to realize the huge market for on-site nitrogen generation. Directive 33 of the Alberta Energy and Utilities Board requires nitrogen to be used in carbon-based atmospheres such as in well testing. In response, the company developed a truck-mounted membrane nitrogen generation system that offers greater purity than other systems. The portable system provides both safety and convenience. The truck-mounted system takes a huge amount of air that is pushed through a membrane or filter, resulting in 44 per cent of the original volume of air produced as pure nitrogen. The nitrogen is put through another compressor and boosted up to the oilfield application pressure. The system produces a waste gas (primarily oxygen) which is vented into the atmosphere. Electricity for the electric system is produced by a diesel engine. The membrane is 5 feet long and 8 inches in diameter. It has an inlet for air and only allows nitrogen to pass through. In designing the system, parameters such as pressure, purity and flow rates were identified. The system is targeted primarily for well servicing applications and is designed to serve approximately 60 per cent of the nitrogen market. It was noted that although membrane systems have limitations and cannot do high rate application such as fracing or coalbed methane, they may be used in underbalanced drilling. In addition to cost savings and convenience, the advantage of a portable nitrogen system over liquid nitrogen is the elimination of venting loss associated with liquid nitrogen transportation. 3 figs.

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

  14. Bacteria and the Nitrogen Economy. (United States)

    Ayanaba, A.


    Biological nitrogen fixation accounts for almost 70 percent of nitrogen for plant growth. If food is to keep abreast of population growth, even more nitrogen must be fixed. For this international research institutes continue the search for natural variants in the bacterial population while also pursuing novel genetic engineering methods. (Author)

  15. The automatic liquid nitrogen filling system for GDA detectors

    Indian Academy of Sciences (India)

    The filling is aborted if the software detects any hardware malfunction and an alarm is sounded. A simplified flow chart of the control program for the filling of the first six detectors is shown in figure 3. A LINUX based program has now been developed with graphical user interface. It uses client-server protocol to communicate ...

  16. Effectiveness of liquid organic-nitrogen fertilizer in enhancing ...

    African Journals Online (AJOL)



    Mar 21, 2011 ... 2Department of Forest Management, Faculty of Forestry, Universiti Putra Malaysia,43400 UPM Serdang Selangor,. Malaysia. Accepted 21 January ... Previous data showed that, uptake of P by corn increased more ..... Prentice Hall, Inc. Upper Saddle River, New Jersey, United. State of America, pp. 217-244.

  17. Isolating silkworm genomic DNA without liquid nitrogen suitable for ...

    African Journals Online (AJOL)



    Sep 21, 2011 ... Cluster analysis based on Jaccard's similarity coefficients resulted in the formation of two main clusters with S9 on one cluster ..... Isolation, characterization and inhibition by garlic extract. Phytotheraphy Res. 16: 89-90. Chowdhury SN (1983). Eri silk industry. Directorate of Seric. Weaving,. Government of ...

  18. A quick DNA extraction protocol: Without liquid nitrogen in ambient ...

    African Journals Online (AJOL)

    Marker assisted selection is an effective technique for quality traits selection in breeding program which are impossible by visual observation. Marker assisted selection in early generation requires rapid DNA extraction protocol for large number of samples in a low cost approach. A rapid and inexpensive DNA extraction ...

  19. Cryopreservation of an avian spirochete strain in liquid nitrogen

    Directory of Open Access Journals (Sweden)

    Labruna M.B.


    Full Text Available Soros de aves experimentalmente infectadas, contendo espiroquetas viáveis, foram submetidos a dois procedimentos antes da criopreservação: glicerol na diluição de 1/2 (v/v, designado como soro com glicerol a 50% (GS, e dimetilsulfóxido na proporção de 1/10 (v/v, designado como soro com DMSO a 10% (DS. Após 15 meses de estocagem em nitrogênio líquido, amostras dos tratamentos GS e DS foram descongeladas e suas infectividades foram testadas em frangos susceptíveis. Apesar de ambos os procedimentos terem mantidos a infectividade da bactéria, DMSO a 10% no soro de frango apresentou-se mais satisfatório como criopreservante.

  20. Effects of Nitrogen Segregation and Solubility on the Formation of Nitrogen Gas Pores in 21.5Cr-1.5Ni Duplex Stainless Steel (United States)

    Zhu, Hong-Chun; Jiang, Zhou-Hua; Li, Hua-Bing; Feng, Hao; Zhang, Shu-Cai; Liu, Guo-Hai; Zhu, Jun-Hui; Wang, Peng-Bo; Zhang, Bin-Bin; Fan, Guang-Wei; Li, Guo-Ping


    The nitrogen gas pore-formation mechanism was discussed with regard to the solidification of 21.5Cr-1.5Ni duplex stainless steels (DSSs) by considering nitrogen segregation and solubility. The segregation behavior of nitrogen was investigated with phase transformation using experimental detection methods and Thermo-Calc software calculations. The process associated with the formation of gas pores was illustrated clearly. The factors that influenced the formation of gas pores, including shrinkage, nitrogen content, solidification pressure, and alloying elements (Mn and Cr), were discussed in detail. The formation of nitrogen-rich phases [austenite phase (FCC), AlN, and hexagonal close packed] is beneficial to eliminate nitrogen segregation and suppressing gas pore formation. The nitrogen-depleted phase (ferrite phase (BCC)) exhibits an opposite effect. Regular gas pores are initially formed in locations consisting of the austenite phase. As the gas pores lengthen, ferrite and austenite phases alternately form around the gas pores. Solidification shrinkage can promote the formation of irregular gas pores at the centerline of the ingots. Increasing the nitrogen content is favorable to the formation of gas pores. Increasing solidification pressure is effective with regard to suppressing the formation of gas pore defects in DSSs. Increasing the Mn content can reduce the likelihood of gas pore formation; this can be attributed to the increased nitrogen solubility in the residual liquid surrounding the dendrites and the formation tendency of the nitrogen-rich phase. Increasing the Cr content exhibits a dual effect on gas pore formation, which is caused by the increased nitrogen solubility and segregation in the residual liquid.

  1. NITROJET: decontamination, cutting and concrete scabbling by nitrogen technology

    Energy Technology Data Exchange (ETDEWEB)

    Damerval, Frederique [AREVA NC - Clean-Up BU, 1 route de la Noue, 91196 Gif sur Yvette, Cedex (France); Varet, Thierry [AREVA NC, Nuclear Site Value Development BU (France); Debionne, Thierry [NCE, NITROCISION (Luxembourg); Richard, Frederic [AIR LIQUIDE C.T.A.S. (France)


    STMI, subsidiary company of the AREVA Group with over 40 years in the D and D business, has been continuously innovating and developing new, decontamination, cleaning and cutting techniques, with the objectives of achieving more efficient decontaminations and cuttings on a growing spectrum of media. In the past years, it has partnered with AIR LIQUIDE, world leader in industrial and medical gases and NITROCISION, a US based company, to develop and commercialize in the nuclear field a revolutionary D and D technology 'NITROJET' patented by NITROCISION and based on pressurized cryogenic nitrogen. This technology uses nitrogen at low temperature (-140 deg. C) and extreme pressure (3 500 bar) to decontaminate or scrabble all types of surfaces: metals, polymers, concrete. Cutting operations can also be carried out by addition of abrasive materials. Liquid nitrogen is collected from a tank to be pressurized in a specific skid which includes a combination of pumps and heat exchangers. The nitrogen stream can then be applied on the substrate. A combination of phenomenon can be distinguished when applying the nitrogen jet: mechanical effect thanks to the high kinetics energy of the stream, thermal impact, blast impact due to the vaporization of the nitrogen and finally solvent power. Advantages of the technology are plentiful; indeed no secondary waste are produced because liquid nitrogen quickly converts to a gas, there is no hot spot, nitrogen is an inert/non-flammable gas providing a safe environment, this is a dry technology (no effluents) and further more the process can be deployed manually with hand held tools, or remotely with the use of robotics. Finally the operating rate is high compared to other mechanical techniques (concrete scabbling) or classic decontamination processes (gels, foams..) which implies a cutback in the operation durations. For example, for concrete, the system is able to scrabble up to 25 mm of concrete in one pass. A vacuum capture

  2. Molecular nitrogen yields from fuel nitrogen in backmixed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, R.C.; Monteith, L.E.; Malte, P.C.


    The major species disposition of nitrogen from pyridine, added to a propane-argon-oxygen stream burned in a jet-stirred reactor, was investigated. Fuel/oxidant equivalence ratio ranged from 0.9 to 1.5, residence time from 10-50 ms, and temperature from 1500-1900/sup 0/K. Nitrogen mass fraction relative to propane plus pyridine was normally 0.01, in a few cases 0.02. Molecular nitrogen (measured by gas chromatograph) included with nitrogen oxides (chemiluminescent analyzer) and ammonia and hydrogen cyanide (wet chemistry) indicate for each reactor setting a complete nitrogen balance consistent with an estimated random error of approximately 10%. Examination of accumulated results for over 20 best quality cases suggest no systematic imbalance. The results are consistent with data from comparison runs using atmospheric air oxidant (hence no molecular nitrogen measurement) with fuel nitrogen provided in the form of pyridine again, and also as ammonia and nitric oxide.

  3. Liquid Methane Conditioning Capabilities Developed at the NASA Glenn Research Center's Small Multi- Purpose Research Facility (SMiRF) for Accelerated Lunar Surface Storage Thermal Testing (United States)

    Bamberger, Helmut H.; Robinson, R. Craig; Jurns, John M.; Grasl, Steven J.


    Glenn Research Center s Creek Road Cryogenic Complex, Small Multi-Purpose Research Facility (SMiRF) recently completed validation / checkout testing of a new liquid methane delivery system and liquid methane (LCH4) conditioning system. Facility checkout validation was conducted in preparation for a series of passive thermal control technology tests planned at SMiRF in FY10 using a flight-like propellant tank at simulated thermal environments from 140 to 350K. These tests will validate models and provide high quality data to support consideration of LCH4/LO2 propellant combination option for a lunar or planetary ascent stage.An infrastructure has been put in place which will support testing of large amounts of liquid methane at SMiRF. Extensive modifications were made to the test facility s existing liquid hydrogen system for compatibility with liquid methane. Also, a new liquid methane fluid conditioning system will enable liquid methane to be quickly densified (sub-cooled below normal boiling point) and to be quickly reheated to saturation conditions between 92 and 140 K. Fluid temperatures can be quickly adjusted to compress the overall test duration. A detailed trade study was conducted to determine an appropriate technique to liquid conditioning with regard to the SMiRF facility s existing infrastructure. In addition, a completely new roadable dewar has been procured for transportation and temporary storage of liquid methane. A new spherical, flight-representative tank has also been fabricated for integration into the vacuum chamber at SMiRF. The addition of this system to SMiRF marks the first time a large-scale liquid methane propellant test capability has been realized at Glenn.This work supports the Cryogenic Fluid Management Project being conducted under the auspices of the Exploration Technology Development Program, providing focused cryogenic fluid management technology efforts to support NASA s future robotic or human exploration missions.

  4. Effect of temperature on the morphology and electro-optical properties of liquid crystal physical gel

    Energy Technology Data Exchange (ETDEWEB)

    Leaw, W.L. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Mamat, C.R., E-mail: [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Triwahyono, S. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Jalil, A.A. [Department of Chemical Engineering, Faculty of Chemical and Energy Engineering, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Centre of Hydrogen Energy, Institute of Future Energy, Univerisiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia); Bidin, N. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310, UTM Johor Bahru, Johor (Malaysia)


    Liquid crystal physical gels were (thermally) prepared with cholesteryl stearate as a gelator in nematic liquid crystal, 4-cyano-4′-pentylbiphenyl. The electro-optical performance of liquid crystal physical gels is almost entirely dependent on the gels' inherent morphology. This study involved an empirical investigation of the relationships among all of the gelation temperature, morphology, and electro-optical properties. Besides continuous cooling at room temperature, isothermal cooling was also performed at both 18 and 0 °C, corresponding to near-solid and solid phases of 4-cyano-4′-pentylbiphenyl respectively. Nevertheless, the liquid crystal physical gel was also isothermally rapidly cooled using liquid nitrogen. Polarizing optical microscopy showed that the gel structure became thinner when isothermal cooling was carried out. These thinner gel aggregates then interconnected to form larger liquid crystal domains. Moreover, it was also revealed that the gel networks were randomized. Electron spin resonance results showed that the liquid crystal director orientation was severely randomized in the presence of gel networks. Conversely, isothermal cooling using liquid nitrogen generated a higher liquid crystal director orientation order. The 6.0 wt% cholesteryl stearate/4-cyano-4′-pentylbiphenyl physical gel that was isothermally cooled using liquid nitrogen showed the lowest response time in a twisted nematic mode optical cell. - Graphical abstract: Liquid crystal physical gel was prepared using nematic liquid crystal, 4-cyano-4′-pentylbiphenyl and cholesteryl stearate as gelator. Isothermal cooling at lower temperature produced thinner gel network and larger liquid crystal domain. - Highlights: • 5CB nematic liquid crystal was successfully gelled by cholesteryl stearate gelator. • The morphology of gel network was controlled by different cooling conditions. • Thinner gel network was formed by the rapid cooling using liquid nitrogen.

  5. Nitrogen fixation on early Mars and other terrestrial planets: experimental demonstration of abiotic fixation reactions to nitrite and nitrate. (United States)

    Summers, David P; Khare, Bishun


    Understanding the abiotic fixation of nitrogen is critical to understanding planetary evolution and the potential origin of life on terrestrial planets. Nitrogen, an essential biochemical element, is certainly necessary for life as we know it to arise. The loss of atmospheric nitrogen can result in an incapacity to sustain liquid water and impact planetary habitability and hydrological processes that shape the surface. However, our current understanding of how such fixation may occur is almost entirely theoretical. This work experimentally examines the chemistry, in both gas and aqueous phases, that would occur from the formation of NO and CO by the shock heating of a model carbon dioxide/nitrogen atmosphere such as is currently thought to exist on early terrestrial planets. The results show that two pathways exist for the abiotic fixation of nitrogen from the atmosphere into the crust: one via HNO and another via NO(2). Fixation via HNO, which requires liquid water, could represent fixation on a planet with liquid water (and hence would also be a source of nitrogen for the origin of life). The pathway via NO(2) does not require liquid water and shows that fixation could occur even when liquid water has been lost from a planet's surface (for example, continuing to remove nitrogen through NO(2) reaction with ice, adsorbed water, etc.).

  6. Impact of heat and mass transfer during the transport of nitrogen in coal porous media on coal mine fires. (United States)

    Shi, Bobo; Zhou, Fubao


    The application of liquid nitrogen injection is an important technique in the field of coal mine fire prevention. However, the mechanism of heat and mass transfer of cryogenic nitrogen in the goaf porous medium has not been well accessed. Hence, the implementation of fire prevention engineering of liquid nitrogen roughly relied on an empirical view. According to the research gap in this respect, an experimental study on the heat and mass transfer of liquid nitrogen in coal porous media was proposed. Overall, the main mechanism of liquid nitrogen fire prevention technology in the coal mine is the creation of an inert and cryogenic atmosphere. Cryogenic nitrogen gas vapor cloud, heavier than the air, would cause the phenomenon of "gravity settling" in porous media firstly. The cryogen could be applicable to diverse types of fires, both in the openings and in the enclosures. Implementation of liquid nitrogen open-injection technique in Yangchangwan colliery achieved the goals of fire prevention and air-cooling. Meanwhile, this study can also provide an essential reference for the research on heat and mass transfer in porous media in the field of thermal physics and engineering.

  7. Freezing Nitrogen Ethanol Composite May be a Viable Approach for Cryotherapy of Human Giant Cell Tumor of Bone. (United States)

    Wu, Po-Kuei; Chen, Cheng-Fong; Wang, Jir-You; Chen, Paul Chih-Hsueh; Chang, Ming-Chau; Hung, Shih-Chieh; Chen, Wei-Ming


    Liquid nitrogen has been used as adjuvant cryotherapy for treating giant cell tumor (GCT) of bone. However, the liquid phase and ultrafreezing (-196° C) properties increase the risk of damage to the adjacent tissues and may lead to perioperative complications. A novel semisolid cryogen, freezing nitrogen ethanol composite, might mitigate these shortcomings because of less-extreme freezing. We therefore wished to evaluate freezing nitrogen ethanol composite as a coolant to determine its properties in tumor cryoablation. (1) Is freezing nitrogen ethanol composite-mediated freezing effective for tumor cryoablation in an ex vivo model, and if yes, is apoptosis involved in the tumor-killing mechanism? (2) Does freezing nitrogen ethanol composite treatment block neovascularization and neoplastic progression of the grafted GCTs and is it comparable to that of liquid nitrogen in an in vivo chicken model? (3) Can use of freezing nitrogen ethanol composite as an adjuvant to curettage result in successful short-term treatment, defined as absence of GCT recurrence at a minimum of 1 year in a small proof-of-concept clinical series? The cryogenic effect on bone tissue mediated by freezing nitrogen ethanol composite and liquid nitrogen was verified by thermal measurement in a time-course manner. Cryoablation on human GCT tissue was examined ex vivo for effect on morphologic features (cell shrinkage) and DNA fragmentation (apoptosis). The presumed mechanism was investigated by molecular analysis of apoptosis regulatory proteins including caspases 3, 8, and 9 and Bax/Bcl-2. Chicken chorioallantoic membrane was used as an in vivo model to evaluate the effects of freezing nitrogen ethanol composite and liquid nitrogen treatment on GCT-derived neovascularization and tumor neoplasm. A small group of patients with GCT of bone was treated by curettage and adjuvant freezing nitrogen ethanol composite cryotherapy in a proof-of-concept study. Tumor recurrence and perioperative

  8. Preliminary Study of a Piston Pump for Cryogenic Fluids (United States)

    Biermann, Arnold E.; Kohl, Robert C.


    Preliminary data are presented covering the performance of a low-speed, five-cylinder piston pump designed for handling boiling hydrogen. This pump was designed for a flow of 55 gallons per minute at 240 rpm with a discharge pressure of 135 pounds per square inch. Tests were made using JP-4 fuel, liquid nitrogen, and liquid hydrogen. Pump delivery and endurance characteristics were satisfactory for the range of operation covered. In connection with the foregoing pump development, the cavitation characteristics of a preliminary visual model, glass-cylinder pump and of a simple reciprocating disk were studied. Subcooling of approximately 0.60 F was obtained from the cavitation produced by reciprocating a disk in boiling nitrogen and in boiling water. The subcooling obtained in a similar manner with liquid hydrogen was somewhat less.

  9. Is nitrogen the next carbon? (United States)

    Battye, William; Aneja, Viney P.; Schlesinger, William H.


    Just as carbon fueled the Industrial Revolution, nitrogen has fueled an Agricultural Revolution. The use of synthetic nitrogen fertilizers and the cultivation of nitrogen-fixing crops both expanded exponentially during the last century, with most of the increase occurring after 1960. As a result, the current flux of reactive, or fixed, nitrogen compounds to the biosphere due to human activities is roughly equivalent to the total flux of fixed nitrogen from all natural sources, both on land masses and in the world's oceans. Natural fluxes of fixed nitrogen are subject to very large uncertainties, but anthropogenic production of reactive nitrogen has increased almost fivefold in the last 60 years, and this rapid increase in anthropogenic fixed nitrogen has removed any uncertainty on the relative importance of anthropogenic fluxes to the natural budget. The increased use of nitrogen has been critical for increased crop yields and protein production needed to keep pace with the growing world population. However, similar to carbon, the release of fixed nitrogen into the natural environment is linked to adverse consequences at local, regional, and global scales. Anthropogenic contributions of fixed nitrogen continue to grow relative to the natural budget, with uncertain consequences.

  10. Boron Nitride nanotube synthesis using liquid arc discharge (United States)

    Holliday, Roger; Falvo, Mike; Washburn, Sean; Superfine, Richard


    We will present results on synthesis of Boron Nitride nanotubes using the liquid nitrogen plasma-arc discharge method previously reported for carbon nanotubes synthesis[1]. We created a 60-100A/20-40V arc across electrodes of Hafnium Boride and Molybdenum Sulfide in a liquid nitrogen atmosphere. Nanotube geometry, nano-structure and composition characterization using TEM and EDAX will be presented. Progress in electronic and mechanical characterization as well as our incorporation of these nanotubes in to novel NEMS devices will be discussed. [1] M. Ishigami, J. C., A. Zettl, S. Chen . Chemical Physical Letters 319 (2000),pp.457-459.

  11. Nitrogen and Oxygen Isotopic Studies of the Marine Nitrogen Cycle. (United States)

    Casciotti, Karen L


    The marine nitrogen cycle is a complex web of microbially mediated reactions that control the inventory, distribution, and speciation of nitrogen in the marine environment. Because nitrogen is a major nutrient that is required by all life, its availability can control biological productivity and ecosystem structure in both surface and deep-ocean communities. Stable isotopes of nitrogen and oxygen in nitrate and nitrite have provided new insights into the rates and distributions of marine nitrogen cycle processes, especially when analyzed in combination with numerical simulations of ocean circulation and biogeochemistry. This review highlights the insights gained from dual-isotope studies applied at regional to global scales and their incorporation into oceanic biogeochemical models. These studies represent significant new advances in the use of isotopic measurements to understand the modern nitrogen cycle, with implications for the study of past ocean productivity, oxygenation, and nutrient status.

  12. Understanding Nitrogen Fixation

    Energy Technology Data Exchange (ETDEWEB)

    Paul J. Chirik


    The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The

  13. Isotopic Discrimination of Some Solutes in Liquid Ammonia (United States)

    Taube, H.; Viste, A.


    The nitrogen isotopic discrimination of some salts and metals, studies in liquid ammonia solution at -50�C, decreases in magnitude in the order Pb{sup ++}, Ca{sup ++}, Li{sup +}, AG{sup +}, Na{sup +}, Li, K{sup +}, Na, K. The isotopic discrimination appears to provide qualitative information about the strength of the cation-solvent interaction in liquid ammonia.

  14. Influence of Nitrogen Source, Thiamine, and Light on Biosynthesis of Abscisic Acid by Cercospora rosicola Passerini


    Norman, Shirley M.; Maier, Vincent P.; Echols, Linda C.


    Abscisic acid production by Cercospora rosicola Passerini in liquid shake culture was measured with different amino acids in combination and singly as nitrogen sources and with different amounts of thiamine in the media. Production of abscisic acid was highest with aspartic acid-glutamic acid and aspartic acid-glutamic acid-serine mixtures as nitrogen sources. Single amino acids that supported the highest production of abscisic acid were asparagine and monosodium glutamate. Thiamine was impor...

  15. An experimental investigation on liquid methane heat transfer enhancement through the use of longitudinal fins in cooling channels (United States)

    Galvan, Manuel de Jesus

    In the past years, hydrocarbon fuels have been the focus of attention as the interest in developing reusable, high-performing liquid rocket engines has grown. Liquid methane (LCH4) has been of particular interest because of the cost, handling, and storage advantages that it presents when compared to currently used propellants. Deep space exploration requires thrusters that can operate reliably during long-duration missions. One of the challenges in the development of a reliable engine has been providing adequate combustion chamber cooling to prevent engine failure. Regenerative (regen) cooling has presented itself as an appealing option because it provides improved cooling and engine efficiency over other types of cooling, such as film or dump cooling. Due to limited availability of experimental sub-critical liquid methane cooling data for pressure-fed regen engine design, there has been an interest in studying the heat transfer characteristics of the propellant. For this reason, recent experimental studies at the Center for Space Exploration Technology Research (cSETR) at the University of Texas at El Paso (UTEP) have focused on investigating the heat transfer characteristics of sub-critical CH4 flowing through smooth sub-scale cooling channels. In addition to investigating smooth channels, the cSETR has conducted experiments to investigate the effects of internal longitudinal fins on the heat transfer of methane. To conduct the experiments, the cSETR developed a conduction-based thermal concentrator known as the High Heat Flux Test Facility (HHFTF) in which the channels are heated. In this study, a smooth channel and three channels with longitudinal fins all with cross sectional geometries of 3.2 mm x 3.2 mm were tested. The Nusselt numbers ranged from 70 and 510, and Reynolds numbers were between 50,000 and 128,000. Sub-cooled film-boiling phenomena were discovered in the data pertaining to the smooth and two finned channels. Sub-cooled film-boiling was not

  16. Phase equilibrium of methane and nitrogen at low temperatures - Application to Titan (United States)

    Kouvaris, Louis C.; Flasar, F. M.


    Since the vapor phase composition of Titan's methane-nitrogen lower atmosphere is uniquely determined as a function of the Gibbs phase rule, these data are presently computed via integration of the Gibbs-Duhem equation. The thermodynamic consistency of published measurements and calculations of the vapor phase composition is then examined, and the saturated mole fraction of gaseous methane is computed as a function of altitude up to the 700-mbar level. The mole fraction is found to lie approximately halfway between that computed from Raoult's law, for a gas in equilibrium with an ideal solution of liquid nitrogen and methane, and that for a gas in equilibrium with pure liquid methane.

  17. Nitrogen remobilization in wheat as influenced by nitrogen ...

    African Journals Online (AJOL)

    In addition to nitrogen fertilizer, WD during grain filling reduced nitrogen use efficiency by 30 and 25%, respectively. In the WW treatment, 25% of the N at anthesis was lost at maturity. In contrast, under WD only 6% of the N was lost. High amount of N led to N losses at maturity. Significant negative correlations were found ...

  18. Nitrogen accumulation and residual effects of nitrogen catch crops

    DEFF Research Database (Denmark)

    Jensen, E.S.


    The nitrogen accumulation in Italian ryegrass (Lolium multiflorum Lam.), perennial ryegrass (Lolium perenne L.), white mustard (Sinapis alba L.) and tansy phacelia (Phacelia tanacetifolia L.), under- or aftersown as nitrogen catch crops to spring barley (Hordeum vulgare L.) and field pea (Pisum s...

  19. Modelling Nitrogen Transformation in Horizontal Subsurface Flow ...

    African Journals Online (AJOL)

    Stella II software was used to simulate nitrogen transformation processes. The results show that the most influential nitrogen ... Accretion of organic nitrogen was a major pathway accounting for 0.279 g/m2.d, which is 19.2% of all the influent nitrogen. The accumulation of ammonia nitrogen was found to be high compared to ...

  20. Influence of Carbohydrate and Nitrogen Source on Patulin Production by Penicillium patulum1 (United States)

    Stott, W. T.; Bullerman, L. B.


    A strain of Penicillium patulum, isolated from cheddar cheese, produced patulin when grown on liquid media containing lactose and milk nitrogen sources. Patulin production was affected by the temperature of incubation, the type and amount of carbohydrate, and the type of nitrogen source present. Patulin levels generally were depressed by incubation at 5 C and low carbohydrate levels. Patulin was produced at low levels in the absence of sugars at 5 C when the mold was grown on milk nitrogen sources. No patulin was detected in cultures grown on 25% casein slurries or cheddar cheese, even though growth of the mold was extensive. PMID:1242877

  1. High Speed Compressor for Subcooling Propellants Project (United States)

    National Aeronautics and Space Administration — Propellant densification systems for LH2 require compression systems that develop significant head. In the past this has required multiple stages of compressors...

  2. Thermodynamics of coal liquid/solid systems

    Energy Technology Data Exchange (ETDEWEB)

    Holder, G. D.; Lee, Chang-Ha.


    Thermodynamic data for many organic systems have been developed for the petroleum industry. This data, however, is limited to the paraffinic compounds while the liquids produced in coal liquefaction are highly aromatic and may contain heteroatoms such as sulfur, oxygen and nitrogen. An effort to generate data bases for these aromatic compounds has been recently made. One of the goals of this work is to expand the data bases so that the properties of coal liquefaction products are accurately determined. This effort has three basic components: pure component physical properties; binary vapor pressure data which enables phase behavior to be calculated for binary and, assuming the interaction of unlike molecules are independent of the presence of a third species, multicomponent systems; and vapor pressures of solid-liquid systems as a function of the solids content. This allows the effect that solids have on the distribution of liquids between phases to be calculated. 20 refs., 3 figs., 55 tabs.

  3. Effects of Nitrogen Fertilizers on the Growth and Nitrate Content of Lettuce (Lactuca sativa L.

    Directory of Open Access Journals (Sweden)

    Cheng-Wei Liu


    Full Text Available Nitrogen is an essential element for plant growth and development; however, due to environmental pollution, high nitrate concentrations accumulate in the edible parts of these leafy vegetables, particularly if excessive nitrogen fertilizer has been applied. Consuming these crops can harm human health; thus, developing a suitable strategy for the agricultural application of nitrogen fertilizer is important. Organic, inorganic, and liquid fertilizers were utilized in this study to investigate their effect on nitrate concentrations and lettuce growth. The results of this pot experiment show that the total nitrogen concentration in soil and the nitrate concentration in lettuce increased as the amount of nitrogen fertilizer increased. If the recommended amount of inorganic fertilizer (200 kg·N·ha−1 is used as a standard of comparison, lettuce augmented with organic fertilizers (200 kg·N·ha−1 have significantly longer and wider leaves, higher shoot, and lower concentrations of nitrate.

  4. Hydrodynamics in a pressurized cocurrent gas-liquid trickle bed reactor

    NARCIS (Netherlands)

    Wammes, Wino J.A.; Westerterp, K.R.


    The influence of gas density on total external liquid hold-up, pressure drop and gas-liquid interfacial area, under trickle-flow conditions, and the transition to pulse flow have been investigated with nitrogen or helium as the gas phase up to 7.5 MPa. It is concluded that the hydrodynamics depends

  5. Criopeeling para tratamento de fotodano e ceratoses actínicas: comparação entre nitrogênio líquido e sistema portátil Cryopeeling for treatment of photodamage and actinic keratosis: liquid nitrogen versus portable system

    Directory of Open Access Journals (Sweden)

    Janyana Marcela Doro Deonizio


    Full Text Available FUNDAMENTOS: O criopeeling utiliza a crioterapia difusa não somente nas lesões de ceratose actínica, mas em toda a pele fotodanificada. OBJETIVOS: Comparar dois métodos de criopeeling (nitrogênio líquido e sistema portátil de éter dimetílico, propano e isobutano quanto à eficiência no tratamento de ceratoses actínicas, tolerabilidade do paciente, preferência do paciente e do pesquisador e resultado estético. MÉTODOS: Dezesseis pacientes (n=16 com múltiplas ceratoses actínicas nos antebraços foram submetidos ao criopeeling com nitrogênio líquido em um dos antebraços e com o sistema portátil no outro, randomicamente. RESULTADOS: No tratamento das ceratoses actínicas, o nitrogênio líquido obteve 74% de eficiência e o sistema portátil, 62% (p=0,019. A média da escala visual analógica (0-10 foi 5,7±1,61 com o nitrogênio líquido e 4,3±1,44 com o sistema portátil (p=0,003. Não houve diferença estatística entre os métodos quanto à preferência do paciente e do pesquisador. Na análise das fotos, observou-se melhora do aspecto da pele nos dois tratamentos (p0,05. CONCLUSÕES: A técnica de criopeeling pode ser uma opção no tratamento de fotodano. O sistema portátil pode ser uma alternativa interessante na prática clínica, com boa tolerância e resultados aceitáveis no tratamento de ceratoses actínicasBACKGROUND: Cryopelling uses diffuse cryotherapy not only on lesions of actinic keratosis but all over the photodamaged skin. OBJECTIVES: The aim of this study was to compare two cryopeeling methods (liquid nitrogen- LN and portable system - PS and demonstrate their efficiency in the treatment of actinic keratoses, patient tolerance, researcher and patient preference and aesthetic results. METHODS: Sixteen patients (N = 16 with multiple actinic keratoses on the forearms were subjected to cryopeeling with LN on one of the forearms and PS on the other, randomly. RESULTS: In the treatment of actinic keratoses, LN

  6. An experimental and theoretical study of decentralized gas fired liquid heating

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, Rolf


    The effects on the energy situation in industry when gas fired liquid heaters replace steam have been determined by energy surveys performed in a brewery and a slaughterhouse, measurements of the performance and emissions from liquid heaters installed in these industries, and theoretical analyses of the potential energy. The theoretical study in the first part of the project provides information that allows assessment of the effects on the energy situation, of a part or complete conversion to decentralized heating, under the conditions prevailing in the industries concerned. The second part of the project focused on increasing the liquid heater efficiency and reducing emissions of carbon monoxide and hydrocarbons. Heat transfer and pressure drop for a corrugated tube was investigated experimentally. Empirical correlations for heat transfer and pressure drop for a corrugated tube were developed. These correlations were used in the design model that was developed within this project. The design model was validated against experimental data and data from an industrial application, where a section of the smooth heat exchanger tube was replaced with a corrugated tube. The results show that the design model predicts the outlet flue gas temperature and the heater efficiency quite accurately. The wall temperature at the first corrugation is also predicted with reasonable accuracy. These results make it possible to calculate the location where a corrugated tube can be inserted without causing subcooled boiling or severe fouling. It is shown that emissions of carbon monoxide and hydrocarbons can be held at low levels, even when conventional industrial burners are used. The use of nozzles that produce long soft flames increase the risk for large emissions of hydrocarbons and carbon monoxide. 125 refs, 89 figs, 16 tabs

  7. Eighth international congress on nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)


    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  8. Efficiency of nitrogen fertilizers for rice


    Roger, Pierre-Armand; Grant, I. F.; Reddy, P. M.; Watanabe, I


    The photosynthetic biomass that develops in the floodwater of wetland rice fields affects nitrogen dynamics in the ecosystem. This review summarizes available data on the nature, productivity, and composition of the photosynthetic aquatic biomass, and its major activities regarding the nitrogen cycle, i.e., nitrogen fixation by free living blue-green algae and #Azolla$, nitrogen trapping, nitrogen accumulation at the soil surface, its effect on nitrogen losses by ammonia volatilization, nitro...

  9. Energy and materials flows in the production of liquid and gaseous oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Shen, S.; Wolsky, A.M.


    Liquid and gaseous oxygen is produced in an energy-intensive air separation processo that also generates nitrogen. More than 65% of the cost of oxygen is attributable to energy costs. Energy use and materials flows are analyzed for various air separation methods. Effective approaches to energy and material conservation in air separation plants include efficient removal of contaminants (carbon dioxide and water), centralization of air products user-industries so that large air separation plants are cost-effective and the energy use in transportation is minimized, and increased production of nitrogen. Air separation plants can produce more than three times more nitrogen than oxygen, but present markets demand, at most, only 1.5 times more. Full utlization of liquid and gaseous nitrogen should be encouraged, so that the wasted separation energy is minimized. There are potential markets for nitrogen in, for example, cryogenic separation of metallic and plastic wastes, cryogenic particle size reduction, and production of ammonia for fertilizer.

  10. Nitrogen sources affect productivity, desiccation tolerance, and storage stability of Beauveria bassiana blastospores. (United States)

    Mascarin, Gabriel M; Kobori, Nilce N; Jackson, Mark A; Dunlap, Christopher A; Delalibera, Ítalo


    Nitrogen is a critical element in industrial fermentation media. This study investigated the influence of various nitrogen sources on blastospore production, desiccation tolerance, and storage stability using two strains of the cosmopolitan insect pathogenic fungus Beauveria bassiana. Complex organic sources of nitrogen such as soy flour, autolyzed yeast and cottonseed flour induced great numbers of blastospores after 2-3 days of fermentation, which also survived drying and remained viable (32-56% survival) after 9 months storage at 4 °C, although variations were found between strains. Nitrogen availability in the form of free amino acids directly influenced blastospore production and resistance to desiccation. Increasing glucose and nitrogen concentrations up to 120 g L-1 and 30 g L-1 , respectively, did not improve blastospore production but enhanced desiccation tolerance. Cell viability after drying and upon fast-rehydration was increased when ≥ 25 g acid hydrolyzed casein L-1 was supplemented in the liquid culture medium. These findings indicate that low-cost complex nitrogen compounds are suitable to enhance yeast-like growth by B. bassiana with good desiccation tolerance and therefore support its further scale-up production as a mycoinsecticide. Nitrogen is the most expensive nutrient in liquid media composition, but this study underscores the feasibility of using low-cost nitrogen compounds composed mainly of agro-industrial by-products for rapid production of desiccation tolerant B. bassiana blastospores by liquid culture fermentation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  11. On the Extraction of Aromatic Compounds from Hydrocarbons by Imidazolium Ionic Liquids


    Jairton Dupont; Chiaro,Sandra S. X.; Bauer Ferrera; Günter Ebeling; Umpierre, Alexandre P.; Cláudia C. Cassol


    The liquid-liquid equilibrium for the ternary system formed by n-octane and aromatic (alkylbenzenes) and heteroaromatic compounds (nitrogen and sulfur containing heterocyles) and 1-alkyl-3-methylimidazolium ionic liquids (ILs) associated with various anions has been investigated. The selectivity on the extraction of a specific aromatic compound is influenced by anion volume, hydrogen bond strength between the anion and the imidazolium cation and the length of the 1-methyl-3-alkylimidazolium a...

  12. Acoustic Emission Monitoring of the DC-XA Composite Liquid Hydrogen Tank During Structural Testing (United States)

    Wilkerson, C.


    The results of acoustic emission (AE) monitoring of the DC-XA composite liquid hydrogen tank are presented in this report. The tank was subjected to pressurization, tensile, and compressive loads at ambient temperatures and also while full of liquid nitrogen. The tank was also pressurized with liquid hydrogen. AE was used to monitor the tank for signs of structural defects developing during the test.

  13. Ultrasound in gas–liquid systems: Effects on solubility and mass transfer


    Laugier, Frédéric; Andriantsiferana, Caroline; Wilhelm, Anne-Marie; Delmas, Henri


    The effect of ultrasound on the pseudo-solubility of nitrogen in water and on gas–liquid mass transfer kinetics has been investigated in an autoclave reactor equipped with a gas induced impeller. In order to use organic liquids and to investigate the effect of pressure, gas–liquid mass transfer coefficient was calculated from the evolution of autoclave pressure during gas absorption to avoid any side-effects of ultrasound on the concentrations measurements. Ultrasound effect on the apparent s...

  14. Aporphine alkaloid contents increase with moderate nitrogen supply in Annona diversifolia Saff. (Annonaceae) seedlings during diurnal periods. (United States)

    Orozco-Castillo, José Agustín; Cruz-Ortega, Rocío; Martinez-Vázquez, Mariano; González-Esquinca, Alma Rosa


    Aporphine alkaloids are secondary metabolites that are obtained in low levels from species of the Annonaceae family. Nitrogen addition may increase the alkaloid content in plants. However, previous studies published did not consider that nitrogen could change the alkaloid content throughout the day. We conducted this short-term study to determine the effects of nitrogen applied throughout the diurnal period on the aporphine alkaloids via measurements conducted on the roots, stems and leaves of Annona diversifolia seedlings. The 60-day-old seedlings were cultured with the addition of three levels of nitrogen (0, 30 and 60 mM), and alkaloid extracts were analysed using high-performance liquid chromatography. The highest total alkaloid content was measured in the treatment with moderate nitrogen supply. Further, the levels of aporphine alkaloids changed significantly in the first few hours of the diurnal period. We conclude that aporphine alkaloid content increased with moderate nitrogen supply and exhibited diurnal variation.

  15. Environmental friendly nitrogen fertilization. (United States)

    Shaviv, Avi


    With the huge intensification of agriculture and the increasing awareness to human health and natural resources sustainability, there was a shift towards the development of environmental friendly N application approaches that support sustainable use of land and sustain food production. The effectiveness of such approaches depends on their ability to synchronize plant nitrogen demand with its supply and the ability to apply favored compositions and dosages of N-species. They are also influenced by farming scale and its sophistication, and include the following key concepts: (i) Improved application modes such as split or localized ("depot") application; (ii) use of bio-amendments like nitrification and urease inhibitors and combinations of (i) and (ii); (iii) use of controlled and slow release fertilizers; (iv) Fertigation-fertilization via irrigation systems including fully automated and controlled systems; and (v) precision fertilization in large scale farming systems. The paper describes the approaches and their action mechanisms and examines their agronomic and environmental significance. The relevance of the approaches for different farming scales, levels of agronomic intensification and agro-technical sophistication is examined as well.

  16. Abiotic nitrogen fixation on terrestrial planets: reduction of NO to ammonia by FeS. (United States)

    Summers, David P; Basa, Ranor C B; Khare, Bishun; Rodoni, David


    Understanding the abiotic fixation of nitrogen and how such fixation can be a supply of prebiotic nitrogen is critical for understanding both the planetary evolution of, and the potential origin of life on, terrestrial planets. As nitrogen is a biochemically essential element, sources of biochemically accessible nitrogen, especially reduced nitrogen, are critical to prebiotic chemistry and the origin of life. Loss of atmospheric nitrogen can result in loss of the ability to sustain liquid water on a planetary surface, which would impact planetary habitability and hydrological processes that shape the surface. It is known that NO can be photochemically converted through a chain of reactions to form nitrate and nitrite, which can be subsequently reduced to ammonia. Here, we show that NO can also be directly reduced, by FeS, to ammonia. In addition to removing nitrogen from the atmosphere, this reaction is particularly important as a source of reduced nitrogen on an early terrestrial planet. By converting NO directly to ammonia in a single step, ammonia is formed with a higher product yield (~50%) than would be possible through the formation of nitrate/nitrite and subsequent conversion to ammonia. In conjunction with the reduction of NO, there is also a catalytic disproportionation at the mineral surface that converts NO to NO₂ and N₂O. The NO₂ is then converted to ammonia, while the N₂O is released back in the gas phase, which provides an abiotic source of nitrous oxide.

  17. Total Nitrogen in Surface Water (United States)

    U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALN is reported in kilograms/hectare/year. More information about these resources, including the...

  18. The nitrogen cycle on Mars (United States)

    Mancinelli, Rocco L.


    Nirtogen is an essential element for the evolution of life, because it is found in a variety of biologically important molecules. Therefore, N is an important element to study from a exobiological perspective. In particular, fixed nitrogen is the biologically useful form of nitrogen. Fixed nitrogen is generally defines as NH3, NH4(+), NO(x), or N that is chemically bound to either inorganic or organic molecules, and releasable by hydrolysis to NH3 or NH4(+). On Earth, the vast majority of nitrogen exists as N2 in the atmosphere, and not in the fixes form. On early Mars the same situations probably existed. The partial pressure of N2 on early Mars was thought to be 18 mb, significantly less than that of Earth. Dinitrogen can be fixed abiotically by several mechanisms. These mechanisms include thernal shock from meteoritic infall and lightning, as well as the interaction of light and sand containing TiO2 which produces NH3 that would be rapidly destroyed by photolysis and reaction with OH radicals. These mechanisms could have been operative on primitive Mars.The chemical processes effecting these compounds and possible ways of fixing or burying N in the Martian environment are described. Data gathered in this laboratory suggest that the low abundance of nitrogen along (compared to primitive Earth) may not significantly deter the origin and early evolution of a nitrogen utilizing organisms. However, the conditions on current Mars with respect to nitrogen are quite different, and organisms may not be able to utilize all of the available nitrogen.

  19. From Funding Liquidity to Market Liquidity

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Lund, Jesper; Gyntelberg, Jacob

    This paper shows empirically that funding liquidity drives market liquidity. As it becomes harder to secure term funding in the money markets, liquidity deteriorates in the Danish bond market. We show that the first principal component of bond market liquidity is driven by the market makers......' ability to obtain funding. This effect holds true across both long and short term, government and covered bonds. We use MiFID data which provides a complete transaction level dataset for the Danish market covering both the subprime crisis and the Euro sovereign crisis. Furthermore, we verify the findings...... for other European government bonds using MTS data. The findings suggest that regulatory bond based liquidity buffers for banks will have limited effectiveness....

  20. Nitrogen balance during growth of cauliflower

    NARCIS (Netherlands)

    Everaarts, A.P.


    The potential for loss of nitrogen to the environment during growth of cauliflower was investigated. A comparison was made between cauliflower growth and nitrogen uptake without, and with, nitrogen application of the recommended amount (=225 kg ha-1 minus mineral nitrogen in the soil layer 0–60 cm,

  1. Air plasma treatment of liquid covered tissue: long timescale chemistry (United States)

    Lietz, Amanda M.; Kushner, Mark J.


    Atmospheric pressure plasmas have shown great promise for the treatment of wounds and cancerous tumors. In these applications, the sample is usually covered by a thin layer of a biological liquid. The reactive oxygen and nitrogen species (RONS) generated by the plasma activate and are processed by the liquid before the plasma produced activation reaches the tissue. The synergy between the plasma and the liquid, including evaporation and the solvation of ions and neutrals, is critical to understanding the outcome of plasma treatment. The atmospheric pressure plasma sources used in these procedures are typically repetitively pulsed. The processes activated by the plasma sources have multiple timescales—from a few ns during the discharge pulse to many minutes for reactions in the liquid. In this paper we discuss results from a computational investigation of plasma-liquid interactions and liquid phase chemistry using a global model with the goal of addressing this large dynamic range in timescales. In modeling air plasmas produced by a dielectric barrier discharge over liquid covered tissue, 5000 voltage pulses were simulated, followed by 5 min of afterglow. Due to the accumulation of long-lived species such as ozone and N x O y , the gas phase dynamics of the 5000th discharge pulse are different from those of the first pulse, particularly with regards to the negative ions. The consequences of applied voltage, gas flow, pulse repetition frequency, and the presence of organic molecules in the liquid on the gas and liquid reactive species are discussed.

  2. Liquid Effluent Retention Facility (United States)

    Federal Laboratory Consortium — The Liquid Effluent Retention Facility (LERF) is located in the central part of the Hanford Site. LERF is permitted by the State of Washington and has three liquid...

  3. Instantaneous Liquid Interfaces


    Willard, Adam P.; Chandler, David


    We describe and illustrate a simple procedure for identifying a liquid interface from atomic coordinates. In particular, a coarse grained density field is constructed, and the interface is defined as a constant density surface for this coarse grained field. In applications to a molecular dynamics simulation of liquid water, it is shown that this procedure provides instructive and useful pictures of liquid-vapor interfaces and of liquid-protein interfaces.

  4. High CO{sub 2} solubility in ionic liquids and a tetraalkylammonium-based poly(ionic liquid)

    Energy Technology Data Exchange (ETDEWEB)

    Supasitmongkol, S.; Styring, P. [University of Sheffield, Sheffield (United Kingdom)


    Carbon dioxide (CO{sub 2}) absorption in several imidazolium-based ionic liquids (ILs), pyridinium-based ionic liquids and a tetraalkylammonium-based poly(ionic liquid) (PIL), poly((p-vinylbenzyl) trimethylammonium hexafluorophosphate) P((VBTMA)(PF6)), was studied. The trend of CO{sub 2} solubility in all of the ILs increases dramatically with decreasing absorption temperature. Based on the same bis(triflamide) (Tf2N) anion, imidazolium, pyridinium and trihexyltetradecylphosphonium-based ionic liquids all show relatively similar CO{sub 2} solubilities, which were higher than for the ES anion. The highest CO{sub 2} absorption was found in a poly(ionic liquid) P((VBTMA)(PF6)); however, the monomer also showed higher CO{sub 2} capacity than the other ionic liquids. The poly(ionic liquid) is remarkable in that it can adsorb 77% of its body weight of CO{sub 2} with a selectivity over nitrogen of 70:1. The absorbed CO{sub 2} gas can be readily desorbed from ionic liquids and poly(ionic liquid) and the selectivity for CO{sub 2} over N{sub 2} was consistent over repeated cycles. The materials can be reused several times for consecutive sorption/desorption cycles, without loss of performance in a large-scale reactor and therefore represent serious candidates for use in commercial adsorbers.

  5. Nitrogen nutrition effects on development, growth and nitrogen accumulation of vegetables

    NARCIS (Netherlands)

    Biemond, H.


    In order to be able to match nitrogen supply and nitrogen requirement of vegetable crops, insight is necessary in the responses to nitrogen of important processes of growth and development. This study focused on effects of amount of nitrogen applied and fractionation of nitrogen supply on

  6. Retardation effect of nitrogen compounds and condensed aromatics on shale oil catalytic cracking processing and their characterization. (United States)

    Li, Nan; Chen, Chen; Wang, Bin; Li, Shaojie; Yang, Chaohe; Chen, Xiaobo

    Untreated shale oil, shale oil treated with HCl aqueous solution and shale oil treated with HCl and furfural were used to do comparative experiments in fixed bed reactors. Nitrogen compounds and condensed aromatics extracted by HCl and furfural were characterized by electrospray ionization Fourier transform cyclotron resonance mass spectrometry and gas chromatography and mass spectrometry, respectively. Compared with untreated shale oil, the conversion and yield of liquid products increased considerably after removing basic nitrogen compounds by HCl extraction. Furthermore, after removing nitrogen compounds and condensed aromatics by both HCl and furfural, the conversion and yield of liquid products further increased. In addition, N 1 class species are predominant in both basic and non-basic nitrogen compounds, and they are probably indole, carbazole, cycloalkyl-carbazole, pyridine and cycloalkyl-pyridine. As for the condensed aromatics, most of them possess aromatic rings with two to three rings and zero to four carbon atom.

  7. Toward a nitrogen footprint calculator for Tanzania


    Hutton, Mary Olivia; Leach, A.M.; Leip, Adrian; J. N. Galloway; Bekunda, M.; Sullivan, C.; Lesschen, J.P.


    We present the first nitrogen footprint model for a developing country: Tanzania. Nitrogen (N) is a crucial element for agriculture and human nutrition, but in excess it can cause serious environmental damage. The Sub-Saharan African nation of Tanzania faces a two-sided nitrogen problem: while there is not enough soil nitrogen to produce adequate food, excess nitrogen that escapes into the environment causes a cascade of ecological and human health problems. To identify, quantify, and contrib...

  8. Near Infrared Spectroscopy of Liquid Hydrocarbon Mixtures for Understanding the Composition of Titan’s Lakes (United States)

    Hadnott, Bryne; Hodyss, Robert; Cable, Morgan; Vu, Tuan; Hayes, Alexander


    The presence of ethane and methane lakes on Titan was confirmed by the Cassini Visible and Infrared Mapping Spectrometer (VIMS) data in 2008, and has been investigated in further detail by the Cassini radar instrument (Brown et al, 2008; Pailloue et al, 2008). Modeled compositions suggest that the lakes are predominantly liquid ethane, with liquid methane, propane, and butane; however, pure liquid methane lakes (such as Ligeia Mare) may also be present (Cordier et al, 2009; Mastrogiuseppe et al, 2014). We present a proof-of-concept instrument, consisting of a near infrared (NIR) spectrometer with a fiber optic probe, in order to conduct non-invasive analyses of cryogenic fluids on planetary bodies. To determine the utility of spectroscopy for in-situ studies, we collected transmission spectra of hydrocarbon mixtures, pure methane and ethane endmembers, and nitrogen-saturated hydrocarbons in the NIR region between 900 to 2500 nm; liquid hydrocarbons were measured in a dewar filled with liquid nitrogen, contained within a glove bag pumped with gaseous nitrogen at a total oxygen concentration of mole fraction of methane (or ethane), and comparisons of the modeled linear coefficients with the mole fraction of methane (or ethane) added will yield useful data on how methane, ethane, and dissolved nitrogen mix. Ideally, this information can also be used to better validate theoretical models on hydrocarbon mixing and nitrogen solubility, providing insight on the loss tangent measurements of Titan’s lakes obtained by Mastrogiuseppe from radar altimetry data.

  9. Effects on the structure of monolayer and submonolayer fluid nitrogen films by the corrugation in the holding potential of nitrogen molecules

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing


    of interactions were indicated by the comparison of the calculated and measured isosteric heats of adsorption in fluid films of nitrogen molecules on graphite. The melting temperatures were lowered by 7K and a region of liquid-gas coexistence was observed for films on the smooth graphite surface indicating......The effects of corrugation in the holding potential of nitrogen molecules on the structure of fluid monolayer and submonolayer films of the molecules on a solid substrate was studied using molecular dynamics simulation. Including McLachlan mediation of the intermolecular potential in a model...

  10. Experimental thermal conductivity, thermal diffusivity, and specific heat values for mixtures of nitrogen, oxygen, and argon (United States)

    Perkins, R. A.; Cieszkiewicz, M. T.


    Experimental measurements of thermal conductivity and thermal diffusivity obtained with a transient hot-wire apparatus are reported for three mixtures of nitrogen, oxygen, and argon. Values of the specific heat, Cp, are calculated from these measured values and the density calculated with an equation of state. The measurements were made at temperatures between 65 and 303 K with pressures between 0.1 and 70 MPa. The data cover the vapor, liquid, and supercritical gas phases for the three mixtures. The total reported points are 1066 for the air mixture (78.11 percent nitrogen, 20.97 percent oxygen, and 0.92 percent argon), 1058 for the 50 percent nitrogen, 50 percent oxygen mixture, and 864 for the 25 percent nitrogen, 75 oxygen mixture. Empirical thermal conductivity correlations are provided for the three mixtures.

  11. Dietary nitrogen and fish welfare. (United States)

    Conceição, Luis E C; Aragão, Cláudia; Dias, Jorge; Costas, Benjamín; Terova, Genciana; Martins, Catarina; Tort, Lluis


    Little research has been done in optimizing the nitrogenous fraction of the fish diets in order to minimize welfare problems. The purpose of this review is to give an overview on how amino acid (AA) metabolism may be affected when fish are under stress and the possible effects on fish welfare when sub-optimal dietary nitrogen formulations are used to feed fish. In addition, it intends to evaluate the current possibilities, and future prospects, of using improved dietary nitrogen formulations to help fish coping with predictable stressful periods. Both metabolomic and genomic evidence show that stressful husbandry conditions affect AA metabolism in fish and may bring an increase in the requirement of indispensable AA. Supplementation in arginine and leucine, but also eventually in lysine, methionine, threonine and glutamine, may have an important role in enhancing the innate immune system. Tryptophan, as precursor for serotonin, modulates aggressive behaviour and feed intake in fish. Bioactive peptides may bring important advances in immunocompetence, disease control and other aspects of welfare of cultured fish. Fishmeal replacement may reduce immune competence, and the full nutritional potential of plant-protein ingredients is attained only after the removal or inactivation of some antinutritional factors. This review shows that AA metabolism is affected when fish are under stress, and this together with sub-optimal dietary nitrogen formulations may affect fish welfare. Furthermore, improved dietary nitrogen formulations may help fish coping with predictable stressful events.

  12. Crystalline Kitaev spin liquids (United States)

    Yamada, Masahiko G.; Dwivedi, Vatsal; Hermanns, Maria


    Frustrated magnetic systems exhibit many fascinating phases. Prime among them are quantum spin liquids, where the magnetic moments do not order even at zero temperature. A subclass of quantum spin liquids called Kitaev spin liquids are particularly interesting, because they are exactly solvable, can be realized in certain materials, and show a large variety of gapless and gapped phases. Here we show that nonsymmorphic symmetries can enrich spin liquid phases, such that the low-energy spinon degrees of freedom form three-dimensional Dirac cones or nodal chains. In addition, we suggest a realization of such Kitaev spin liquids in metal-organic frameworks.

  13. Characterizing Dissolved Gases in Cryogenic Liquid Fuels (United States)

    Richardson, Ian A.

    Pressure-Density-Temperature-Composition (PrhoT-x) measurements of cryogenic fuel mixtures are a historical challenge due to the difficulties of maintaining cryogenic temperatures and precision isolation of a mixture sample. For decades NASA has used helium to pressurize liquid hydrogen propellant tanks to maintain tank pressure and reduce boil off. This process causes helium gas to dissolve into liquid hydrogen creating a cryogenic mixture with thermodynamic properties that vary from pure liquid hydrogen. This can lead to inefficiencies in fuel storage and instabilities in fluid flow. As NASA plans for longer missions to Mars and beyond, small inefficiencies such as dissolved helium in liquid propellant become significant. Traditional NASA models are unable to account for dissolved helium due to a lack of fundamental property measurements necessary for the development of a mixture Equation Of State (EOS). The first PrhoT-x measurements of helium-hydrogen mixtures using a retrofitted single-sinker densimeter, magnetic suspension microbalance, and calibrated gas chromatograph are presented in this research. These measurements were used to develop the first multi-phase EOS for helium-hydrogen mixtures which was implemented into NASA's Generalized Fluid System Simulation Program (GFSSP) to determine the significance of mixture non-idealities. It was revealed that having dissolved helium in the propellant does not have a significant effect on the tank pressurization rate but does affect the rate at which the propellant temperature rises. PrhoT-x measurements are conducted on methane-ethane mixtures with dissolved nitrogen gas to simulate the conditions of the hydrocarbon seas of Saturn's moon Titan. Titan is the only known celestial body in the solar system besides Earth with stable liquid seas accessible on the surface. The PrhoT-x measurements are used to develop solubility models to aid in the design of the Titan Submarine. NASA is currently designing the submarine

  14. Terrestrial nitrogen cycles: Some unanswered questions (United States)

    Vitousek, P.


    Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

  15. Insects as a Nitrogen Source for Plants

    Directory of Open Access Journals (Sweden)

    Michael J. Bidochka


    Full Text Available Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates.

  16. Insects as a Nitrogen Source for Plants. (United States)

    Behie, Scott W; Bidochka, Michael J


    Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively) are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF) provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates.

  17. Supplementary nitrogen in leeks based on crop nitrogen status

    NARCIS (Netherlands)

    Booij, R.; Meurs, E.J.J.


    From a number of basic relationships between several crop ecological components (Booij et al., 1996a) a system was developed for giving supplementary nitrogen application in leeks, that was based on the measurement of light interception. A description of the approach is given and a comparison is

  18. nitrate-nitrogen and ammonium- nitrogen levels of some water ...

    African Journals Online (AJOL)


    is increasing while accessibility to available freshwater is on the decrease. Aderibigbe et al. (2008) observed that the human race was becoming increasingly vulnerable due to dependence on polluted water. Compounds of nitrogen have a significant contribution in this pollution. The most important of these compounds are ...

  19. Composite aerogel insulation for cryogenic liquid storage (United States)

    Kyeongho, Kim; Hyungmook, Kang; Soojin, Shin; In Hwan, Oh; Changhee, Son; Hyung, Cho Yun; Yongchan, Kim; Sarng Woo, Karng


    High porosity materials such as aerogel known as a good insulator in a vacuum range (10-3 ∼ 1 Torr) was widely used to storage and to transport cryogenic fluids. It is necessary to be investigated the performance of aerogel insulations for cryogenic liquid storage in soft vacuum range to atmospheric pressure. A one-dimensional insulating experimental apparatus was designed and fabricated to consist of a cold mass tank, a heat absorber and an annular vacuum space with 5-layer (each 10 mm thickness) of the aerogel insulation materials. Aerogel blanket for cryogenic (used maximum temperature is 400K), aerogel blanket for normal temperature (used maximum temperature is 923K), and combination of the two kinds of aerogel blankets were 5-layer laminated between the cryogenic liquid wall and the ambient wall in vacuum space. Also, 1-D effective thermal conductivities of the insulation materials were evaluated by measuring boil-off rate from liquid nitrogen and liquid argon. In this study, the effective thermal conductivities and the temperature-thickness profiles of the two kinds of insulators and the layered combination of the two different aerogel blankets were presented.


    Directory of Open Access Journals (Sweden)

    Qurat E Noor Baig


    Full Text Available Amino acids are the building blocks of proteins and are considered as the key precursors for the formation of hormones and low molecular weight nitrogenous substances with biological importance. Since the analysis of amino acids has been carried out for both qualitative and quantitative purposes with an aim to study their levels in the plasma concentration, the quantitative determination, in particular, also helps in the diagnosis of different diseases associated with their deficiency. This review article deals with the determination of amino acids by chromatographic methods which include ion-exchange chromatography (IEC, high performance liquid chromatography (HPLC, reverse phase-high performance liquid chromatography (RP-HPLC and ultra-performance liquid chromatography (UPLC. The review will also give an idea for the preparation of samples, derivatization methods for the analysis of amino acids (direct and indirect methods and separation of amino acids by high performance liquid chromatographic technique.

  1. Production of nanostructured molecular liquids by supercritical CO2 processing

    Directory of Open Access Journals (Sweden)

    Sudhir Kumar Sharma


    Full Text Available Stable molecular clusters of ibuprofen and naproxen were prepared in dry ice, by supersonic jet expansion of their supercritical CO2 drug formulations into a liquid nitrogen cooled collection vessel, with up to 80% yield. Mixing the “dry ice” in water, resulted in the solubilization of the clusters and in the case of ibuprofen, we were able to create solutions, with concentrations of up to 6 mg/ml, a 300-fold increase over previously reported values. Drop casting and ambient drying of these solutions on silicon substrate resulted in a stable, viscous liquid film, referred to as nanostructured molecular liquids. These liquids exhibited a highly aligned, fine (self-assembled super lattice features. In vitro cancer cell viability studies of these formulations exhibited similar cytotoxicity to that of the original raw materials, thus retaining their original potency. Besides its scientific importance, this invention is expected to open up new drug delivery platforms.

  2. Experimental investigation of two-phase gas-liquid flow in microchannel with T-junction (United States)

    Bartkus, German; Kozulin, Igor; Kuznetsov, Vladimir


    Using high-speed video recording and the method of dual laser scanning the gas-liquid flow was investigated in rectangular microchannels with an aspect ratio of 2.35 and 1.26. Experiments were earned out for the vertical flow of ethanol-nitrogen mixture in a microchannel with a cross section of 553×235 µm and for the horizontal flow of water-nitrogen mixture in a microchannel with a cross section of 315×250 µm. The T-mixer was used at the channel's inlet for gas-liquid flow formation. It was observed that elongated bubble, transition, and annular flows are the main regimes for a microchannel with a hydraulic diameter substantially less than the capillary constant. Using laser scanning, the maps of flow regimes for ethanol-nitrogen and water-nitrogen mixtures were obtained and discussed.

  3. Fabrication and Properties of Micro-Nanoencapsulated Phase Change Materials for Internally-Cooled Liquid Desiccant Dehumidification. (United States)

    Niu, Xiaofeng; Xu, Qing; Zhang, Yi; Zhang, Yue; Yan, Yufeng; Liu, Tao


    Micro-nanoencapsulated phase change materials (M-NEPCMs) are proposed to be useful in liquid desiccant dehumidification by restraining the temperature rise in the moisture-removal process and improving the dehumidification efficiency. In this paper, the n-octadecane M-NEPCMs with desirable thermal properties for internally-cooled dehumidification were fabricated by using compound emulsifiers through the in-situ polymerization method. Melamine-formaldehyde resin was used as the shell material. The effects of the mixing ratio, emulsification methods and amount of the compound emulsifiers on the morphology, size and thermal properties of the M-NEPCMs were investigated experimentally. The optimum weight mixing ratio of the compound emulsifiers is SDS (sodium dodecyl sulfate):Tween80 (polyoxyethylene sorbitan monooleate):Span80 (sorbitan monooleate) = 0.1:0.6:0.3, which achieves the best stability of the n-octadecane emulsion. When the compound emulsifiers are 10 wt. % of the core material, the melting enthalpy of M-NEPCMs reaches its maximum of 145.26 J/g of capsules, with an encapsulation efficiency of 62.88% and a mean diameter of 636 nm. The sub-cooling of the prepared M-NEPCMs is lower than 3 °C, with an acceptable thermal reliability after the thermal cycling test. A pre-emulsification prior to the addition of deionized water in the emulsification is beneficial to the morphology of the capsules, as the phase change enthalpy can be increased by 123.7%.

  4. Methane, Ethane, and Nitrogen Stability on Titan and Other Icy Bodies (United States)

    Hanley, Jennifer; Grundy, Will; Thompson, Garrett; Pearce, Logan; Dustrud, Shyanne; Lindberg, Gerrick; Tegler, Stephen C.; Roe, Henry G.


    Many outer solar system bodies are likely to have a combination of methane, ethane and nitrogen. In particular the lakes of Titan are known to consist of these species. Understanding the past and current stability of these lakes requires characterizing the interactions of methane and ethane, along with nitrogen, as both liquids and ices. Our cryogenic laboratory setup allows us to explore ices down to 30 K through imaging and transmission and Raman spectroscopy. Our recent work has shown that although methane and ethane have similar freezing points, when mixed they can remain liquid down to 72 K. Concurrently with the freezing point measurements we acquire transmission or Raman spectra of these mixtures to understand how the structural features change with concentration and temperature. Any mixing of these two species together will depress the freezing point of the lake below Titan’s surface temperature, preventing them from freezing. We will present new results utilizing our recently acquired Raman spectrometer that allow us to explore both the liquid and solid phases of the ternary system of methane, ethane and nitrogen. In particular we will explore the effect of nitrogen on the eutectic of the methane-ethane system. At high pressure we find that the ternary creates two separate liquid phases. Through spectroscopy we determined the bottom layer to be nitrogen rich, and the top layer to be ethane rich. Identifying the eutectic, as well as understanding the liquidus and solidus points of combinations of these species, has implications for not only the lakes on the surface of Titan, but also for the evaporation/condensation/cloud cycle in the atmosphere, as well as the stability of these species on other outer solar system bodies. These results will help interpretation of future observational data, and guide current theoretical models.

  5. Utilization of nitrogen fixing trees

    Energy Technology Data Exchange (ETDEWEB)

    Brewbaker, J.L.; Beldt, R. van den; MacDicken, K.; Budowski, G.; Kass, D.C.L.; Russo, R.O.; Escalante, G.; Herrera, R.; Aranguren, J.; Arkcoll, D.B.; Doebereinger, J. (cord.)


    Six papers from the symposium are noted. Brewbaker, J.L., Beldt, R. van den, MacDicken, K. Fuelwood uses and properties of nitrogen-fixing trees, pp 193-204, (Refs. 15). Includes a list of 35 nitrogen-fixing trees of high fuelwood value. Budowski, G.; Kass, D.C.L.; Russo, R.O. Leguminous trees for shade, pp 205-222, (Refs. 68). Escalante, G., Herrera, R., Aranguren, J.; Nitrogen fixation in shade trees (Erythrina poeppigiana) in cocoa plantations in northern Venezuela, pp 223-230, (Refs. 13). Arkcoll, D.B.; Some leguminous trees providing useful fruits in the North of Brazil, pp 235-239, (Refs. 13). This paper deals with Parkia platycephala, Pentaclethra macroloba, Swartzia sp., Cassia leiandra, Hymenaea courbaril, dipteryz odorata, Inga edulis, I. macrophylla, and I. cinnamonea. Baggio, A.J.; Possibilities of the use of Gliricidia sepium in agroforestry systems in Brazil, pp 241-243; (Refs. 15). Seiffert, N.F.; Biological nitrogen and protein production of Leucaena cultivars grown to supplement the nutrition of ruminants, pp 245-249, (Refs. 14). Leucaena leucocephala cv. Peru, L. campina grande (L. leucocephala), and L. cunningham (L. leucocephalae) were promising for use as browse by beef cattle in central Brazil.

  6. Can mushrooms fix atmospheric nitrogen?

    Indian Academy of Sciences (India)

    At maximum mycelial colonization by the bradyrhizobial strain and biofilm formation, the cultures were subjected to acetylene reduction assay (ARA). Another set of the cultures was evaluated for growth and nitrogen accumulation. Nitrogenase activity was present in the biofilm, but not when the fungus or the bradyrhizobial ...

  7. Dietary nitrogen and fish welfare

    NARCIS (Netherlands)

    Conceicao, L.E.C.; Aragao, C.; Dias, J.; Costas, B.; Terova, G.; Martins, C.I.; Tort, L.


    Little research has been done in optimizing the nitrogenous fraction of the fish diets in order to minimize welfare problems. The purpose of this review is to give an overview on how amino acid (AA) metabolism may be affected when fish are under stress and the possible effects on fish welfare when

  8. Nitrogen trailer acceptance test report

    Energy Technology Data Exchange (ETDEWEB)

    Kostelnik, A.J.


    This Acceptance Test Report documents compliance with the requirements of specification WHC-S-0249. The equipment was tested according to WHC-SD-WM-ATP-108 Rev.0. The equipment being tested is a portable contained nitrogen supply. The test was conducted at Norco`s facility.

  9. Nitrogen deposition and terrestrial biodiversity (United States)

    Christopher M. Clark; Yongfei Bai; William D. Bowman; Jane M. Cowles; Mark E. Fenn; Frank S. Gilliam; Gareth K. Phoenix; Ilyas Siddique; Carly J. Stevens; Harald U. Sverdrup; Heather L. Throop


    Nitrogen deposition, along with habitat losses and climate change, has been identified as a primary threat to biodiversity worldwide (Butchart et al., 2010; MEA, 2005; Sala et al., 2000). The source of this stressor to natural systems is generally twofold: burning of fossil fuels and the use of fertilizers in modern intensive agriculture. Each of these human...

  10. Artificial wetlands performance: nitrogen removal. (United States)

    Durán-de-Bazúa, Carmen; Guido-Zárate, Alejandro; Huanosta, Thalía; Padrón-López, Rosa Martha; Rodríguez-Monroy, Jesús


    Artificial wetlands (AW) are a promising option for wastewater treatment in small communities due to their high performance in nutrients removal and low operation and maintenance costs. Nitrogen can favour the growth of algae in water bodies causing eutrophication when present at high concentrations. Nitrogen can be removed through different mechanisms (e.g. nitrification-denitrification, adsorption and plant uptake). Environmental conditions such as temperature and relative humidity can play an important role in the performance of these systems by promoting the growth of macrophytes such as reeds and cattails (e.g. Phragmites australis, Typha latifolia respectively). In this paper, two AW systems were compared, one located in Mexico City, Mexico at an altitude higher than 2,000 m above the sea level, and the second one located in Villahermosa, Tabasco, Mexico at an a altitude near the sea level (27 m). Both systems comprised five reactors (147-L plastic boxes) filled with volcanic slag and gravel and intermittently fed with synthetic water. The removal nitrogen efficiency found for the system located in Mexico City was higher than that of the Tabasco system (90 and 80% as TKN respectively). The higher temperatures in the Tabasco system did not enhanced the nitrogen removal as expected. Copyright IWA Publishing 2008.

  11. Foliage nitrogen turnover: differences among nitrogen absorbed at different times by Quercus serrata saplings (United States)

    Ueda, Miki U.; Mizumachi, Eri; Tokuchi, Naoko


    Background and Aims Nitrogen turnover within plants has been intensively studied to better understand nitrogen use strategies. However, differences among the nitrogen absorbed at different times are not completely understood and the fate of nitrogen absorbed during winter is largely uncharacterized. In the present study, nitrogen absorbed at different times of the year (growing season, winter and previous growing season) was traced, and the within-leaf nitrogen turnover of a temperate deciduous oak Quercus serrata was investigated. Methods The contributions of nitrogen absorbed at the three different times to leaf construction, translocation during the growing season, and the leaf-level resorption efficiency during leaf senescence were compared using 15N. Key Results Winter- and previous growing season-absorbed nitrogen significantly contributed to leaf construction, although the contribution was smaller than that of growing season-absorbed nitrogen. On the other hand, the leaf-level resorption efficiency of winter- and previous growing season-absorbed nitrogen was higher than that of growing season-absorbed nitrogen, suggesting that older nitrogen is better retained in leaves than recently absorbed nitrogen. Conclusions The results demonstrate that nitrogen turnover in leaves varies with nitrogen absorption times. These findings are important for understanding plant nitrogen use strategies and nitrogen cycles in forest ecosystems. PMID:21515608

  12. Replenishment and mobilization of intracellular nitrogen pools decouples wine yeast nitrogen uptake from growth. (United States)

    Gutiérrez, Alicia; Sancho, Marta; Beltran, Gemma; Guillamon, José Manuel; Warringer, Jonas


    Wine yeast capacity to take up nitrogen from the environment and catabolize it to support population growth, fermentation, and aroma production is critical to wine production. Under nitrogen restriction, yeast nitrogen uptake is believed to be intimately coupled to reproduction with nitrogen catabolite repression (NCR) suggested mediating this link. We provide a time- and strain-resolved view of nitrogen uptake, population growth, and NCR activity in wine yeasts. Nitrogen uptake was found to be decoupled from growth due to early assimilated nitrogen being used to replenish intracellular nitrogen pools rather than being channeled directly into reproduction. Internally accumulated nitrogen was later mobilized to support substantial population expansion after external nitrogen was depleted. On good nitrogen sources, the decoupling between nitrogen uptake and growth correlated well with relaxation of NCR repression, raising the potential that the latter may be triggered by intracellular build-up of nitrogen. No link between NCR activity and nitrogen assimilation or growth on poor nitrogen sources was found. The decoupling between nitrogen uptake and growth and its influence on NCR activity is of relevance for both wine production and our general understanding of nitrogen use.

  13. Liquid Fermentation of Ganoderma applanatum and Antioxidant Activity of Exopolysaccharides. (United States)

    Zhong-Hua, Liu; Xiao-Ge, Hou; Jin-Hui, Zhao; Le, H E


    The medium composition and fermentation conditions of Ganoderma applanatum(GA) strain were optimized by the liquid shake flask fermentation, and the antioxidant activity of exopolysaccharides was investigated. The results showed that the optimal conditions of the liquid fermentation of GA strain were as follows: Carbon source was corn powder, nitrogen source was soy powder, the initial pH was 6.0, the inoculum size was 8%, the fermentation temperature was 32(o)C, the fermentation time was 7 d. The exopolysaccharides of GA strain could scavenge hydroxyl radicals(HR) and superoxide anion radicals(SAR), and the concentration of exopolysaccharides was positively related to the antioxidant activity.

  14. Developmental competence and gene expression of immature oocytes following liquid helium vitrification in bovine. (United States)

    Chen, Jun-Yi; Li, Xiao-Xia; Xu, Ya-Kun; Wu, Hua; Zheng, Jun-Jun; Yu, Xue-Li


    The objective of this study was to develop an effective ultra-rapid vitrification method and evaluate its effect on maturation, developmental competence and development-related gene expression in bovine immature oocytes. Bovine cumulus oocyte complexes were randomly allocated into three groups: (1) controls, (2) liquid nitrogen vitrification, and (3) liquid helium vitrification. Oocytes were vitrified and then warmed, the percentage of morphologically normal oocytes in liquid helium group (89.0%) was significantly higher (Pvitrification had higher cleavage and blastocyst rates (41.1% and 10.0%) than that of liquid nitrogen vitrification (33.0% and 4.5%; Pvitrification. Expression of GDF9 and BAX in the liquid helium vitrification group was not significantly different from that of the control, however there were significant differences between the liquid nitrogen vitrification group and control. In conclusion, it was feasible to use liquid helium for vitrifying bovine immature oocytes. There existed an association between the compromised developmental competence and the altered expression levels of these genes for the vitrified oocytes. Copyright © 2014 Elsevier Inc. All rights reserved.


    Whatley, M.E.; Woods, W.M.


    This invention relates to liquid-liquid extraction systems. The invention, an improved hydroclone system, comprises a series of serially connected, axially aligned hydroclones, each of which is provided with an axially aligned overflow chamber. The chambers are so arranged that rotational motion of a fluid being passed through the system is not lost in passing from chamber to chamber; consequently, this system is highly efficient in contacting and separating two immiscible liquids. (AEC)

  16. Quantum Spin Liquids


    Savary, Lucile; Balents, Leon


    Quantum spin liquids may be considered "quantum disordered" ground states of spin systems, in which zero point fluctuations are so strong that they prevent conventional magnetic long range order. More interestingly, quantum spin liquids are prototypical examples of ground states with massive many-body entanglement, of a degree sufficient to render these states distinct phases of matter. Their highly entangled nature imbues quantum spin liquids with unique physical aspects, such as non-local e...

  17. Nitrogen effects on silicon growth, defects, and carrier lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Ciszek, T.F.; Wang, T.H.; Burrows, R.W. [National Renewable Energy Lab., Golden, CO (United States)] [and others


    Silicon crystal or multicrystal growth in N{sub 2} or partial-N{sub 2} atmospheres can provide mechanical strengthening, lower purge-gas costs (nitrogen from liquid sources is about a factor of 4 less expensive than argon from liquid sources), and reduce swirl-type microdefect formation in dislocation-free (DF) crystals. There is not much literature on electrical effects of N in Si, including lifetime effects. We studied the effects of Si growth in atmospheres containing N{sub 2} on minority charge carrier lifetime E using the float-zone (FZ) crystal growth method. Ingots were grown with purge gases that ranged from pure argon (99.9995%) to pure N{sub 2} (99-999%). We found that multicrystalline silicon ingot growth in a partial or total nitrogen ambient has a negligible effect on {tau}. Values of 40 {mu}s < {tau} < 100 {mu}s were typical regardless of ambient. For DF growth, the degradation of {tau} is minimal and {tau} values above 1000 {mu}s are obtained if the amount of N{sub 2} in the purge gas is below the level at which nitride compounds form in the melt and disrupt DF growth.

  18. Recent studies of the ocean nitrogen cycle (United States)

    Eppley, R. W.


    The nitrogen cycle in the ocean is dominated by the activities of organisms. External nitrogen inputs from land and from the atmosphere are small compared with rates of consumption and production by organisms and with rates of internal rearrangements of nitrogen pools within the ocean. The chief reservoirs of nitrogen are, in decreasing order of size: nitrogen in sediments, dissolved N2, nitrate, dissolved organic nitrogen (DON), particulate organic nitrogen (PON) (mostly organisms and their by-products). The biogenic fluxes of nitrogen were reviewed. The rate of PON decomposition in the surface layer must be comparable to the rate of ammonium consumption; and at the same time the nitrate consumption rate will be similar to the rates of: (1) sinking of PON out of the surface layer and its decompositon at depth, (2) the rate of nitrification at depth, and (3) the rate of nitrate return to the surface layer by upwelling.

  19. Nitrogen Dioxide's Impact on Indoor Air Quality (United States)

    The two most prevalent oxides of nitrogen are nitrogen dioxide (NO2) and nitric oxide (NO). Both are toxic gases with NO2 being a highly reactive oxidant and corrosive. The primary sources indoors are combustion processes.

  20. Remotely controllable liquid marbles

    KAUST Repository

    Zhang, Lianbin


    Liquid droplets encapsulated by self-organized hydrophobic particles at the liquid/air interface - liquid marbles - are prepared by encapsulating water droplets with novel core/shell-structured responsive magnetic particles, consisting of a responsive block copolymer-grafted mesoporous silica shell and magnetite core (see figure; P2VP-b-PDMS: poly(2-vinylpyridine-b- dimethylsiloxane)). Desirable properties of the liquid marbles include that they rupture upon ultraviolet illumination and can be remotely manipulated by an external magnetic field. 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Modeling nitrogen fluxes in Germany - where does the nitrogen go? (United States)

    Klement, Laura; Bach, Martin; Breuer, Lutz


    According to the latest inventory of the EU Water Framework Directive, 26.3% of German groundwater bodies are in a poor chemical state regarding nitrate. Additionally, the EU initiated infringement proceedings against Germany for not meeting the quality standards of the EU Nitrate Directive. Agriculture has been determined as the main source of nitrate pollution due to over-fertilization and regionally high density of livestock farming. The nitrogen balance surplus is commonly used as an indicator characterizing the potential of nitrate leaching into groundwater bodies and thus also serves as a foundation to introduce legislative restrictions or to monitor the success of mitigation measures. Currently, there is an ongoing discussion which measures are suitable for reducing the risk of nitrate leaching and also to what extent. However, there is still uncertainty about just how much the nitrogen surplus has to be reduced to meet the groundwater quality standards nationwide. Therefore, the aims of our study were firstly to determine the level of the nitrogen surplus that would be acceptable at the utmost and secondly whether the currently discussed target value of 30 kg N per hectare agricultural land for the soil surface nitrogen balance would be sufficient. The models MONERIS (Modeling Nutrient Emissions in River System) and MoRE (Modelling of Regionalized Emissions), the latter based on the first, are commonly used for estimating nitrogen loads into the river system in Germany at the mesoscale, as well as the effect of mitigation measures in the context of the EU directive 2008/105/EC (Environmental quality standards applicable to surface water). We used MoRE to calculate nitrate concentration for 2759 analytical units in Germany. Main factors are the surplus of the soil surface nitrogen balance, the percolation rate and an exponent representing the denitrification in the vadose zone. The modeled groundwater nitrate concentrations did not correspond to the regional

  2. Toward a nitrogen footprint calculator for Tanzania

    NARCIS (Netherlands)

    Hutton, Mary Olivia; Leach, A.M.; Leip, Adrian; Galloway, J.N.; Bekunda, M.; Sullivan, C.; Lesschen, J.P.


    We present the first nitrogen footprint model for a developing country: Tanzania. Nitrogen (N) is a crucial element for agriculture and human nutrition, but in excess it can cause serious environmental damage. The Sub-Saharan African nation of Tanzania faces a two-sided nitrogen problem: while there

  3. 21 CFR 184.1540 - Nitrogen. (United States)


    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrogen. 184.1540 Section 184.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1540 Nitrogen. (a) Nitrogen (empirical formula N2, CAS Reg. No. 7727-37-9...

  4. 46 CFR 154.1755 - Nitrogen. (United States)


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Nitrogen. 154.1755 Section 154.1755 Shipping COAST GUARD... Nitrogen. Except for deck tanks and their piping systems, cargo containment systems and piping systems carrying nitrogen must be specially approved by the Commandant (CG-522). ...

  5. 21 CFR 582.1540 - Nitrogen. (United States)


    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Nitrogen. 582.1540 Section 582.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Nitrogen. (a) Product. Nitrogen. (b) Conditions of use. This substance is generally recognized as safe when...

  6. Deposition of nitrogen into the North Sea

    DEFF Research Database (Denmark)

    Leeuw, G. de; Skjøth, C.A.; Hertel, O.


    The flux of nitrogen species from the atmosphere into the ocean, with emphasis on coastal waters, was addressed during the ANICE project (Atmospheric Nitrogen Inputs into the Coastal Ecosystem). ANICE focused on quantifying the deposition of atmospheric inputs of inorganic nitrogen compounds (HNO3...

  7. Enhanced Biological Phosphorus Removal for Liquid Dairy Manure


    Hong, Yanjuan


    Enhanced biological phosphorus removal (EBPR) has been widely used in municipal wastewater treatment, but no previous studies have examined the application of EBPR to treat dairy manure. This study was conducted to evaluate the (i) performance of pilot-scale EBPR systems treating liquid dairy manure, to balance the ratio of nitrogen to phosphorus in manure to meet crop nutrient requirements, (ii) effects of dissolved oxygen and solids retention time on the efficiency of EBPR, and (iii) effect...

  8. Biochemical composition liquid medium for cultivation of Mycoplasma




    The article discusses the biochemical composition of nutrient media for cultivation of mycoplasmas isolated from animals. In liquid media for cultivation of mycoplasmas on the basis of tryptic digest of the heart of cattle with serum albumin of cattle and horse blood, blood serum of cattle, broiler chickens, horses and the environment were identified as Edward biochemical parameters: total protein and its fractions, cholesterol, triglycerides, amino nitrogen, grain size distribution of lipopr...

  9. Nitrogen Fractions in Arable Soils in Relation to Nitrogen Mineralization and Plant Uptake

    NARCIS (Netherlands)

    Bregliani, M.; Temminghoff, E.J.M.; Riemsdijk, van W.H.; Hagg, E.S.


    Nitrogen (N) as a major constituent of all plants is one of the most important nutrients. Minimizing input of mineral nitrogen fertilizer is needed to avoid harm to the environment. Optimal input of mineral nitrogen should take the nitrogen supply of the soil into account. Many different soil tests

  10. Thermotropic Ionic Liquid Crystals


    Sabine Laschat; Axenov, Kirill V


    The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

  11. Decimalization and market liquidity


    Craig Furfine


    This study examines the stocks of 1, 339 companies that began decimal trading on the NYSE on January 29, 2001. Using the price impact of a trade as a measure of liquidity, the author finds that decimalization typically led to an improvement in liquidity.

  12. The Liquid Vapour Interface

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage


    In this short review we are concerned with the density variation across the liquid-vapour interface, i.e. from the bulk density of the liquid to the essentially zero density of the vapour phase. This density variation can in principle be determined from the deviation of the reflectivity from...

  13. Enantioseparation with liquid membranes

    NARCIS (Netherlands)

    Gössi, Angelo; Riedl, Wolfgang; Schuur, Boelo


    Chiral resolution of racemic products is a challenging and important task in the pharmaceutical, agrochemical, flavor, polymer and fragrances industries. One of the options for these challenging separations is to use liquid membranes. Although liquid membranes have been known for almost four decades

  14. The TIPS Liquidity Premium

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Simon Riddell, Simon

    We introduce an arbitrage-free term structure model of nominal and real yields that accounts for liquidity risk in Treasury inflation-protected securities (TIPS). The novel feature of our model is to identify liquidity risk from individual TIPS prices by accounting for the tendency that TIPS, lik...

  15. Ionic and Molecular Liquids

    DEFF Research Database (Denmark)

    Chaban, Vitaly V.; Prezhdo, Oleg


    applications of RTILs in combination with molecular liquids, concentrating on three significant areas: (1) the use of molecular liquids to decrease the viscosity of RTILs; (2) the role of RTIL micelle formation in water and organic solvents; and (3) the ability of RTILs to adsorb pollutant gases. Current...

  16. INEEL Liquid Effluent Inventory

    Energy Technology Data Exchange (ETDEWEB)

    Major, C.A.


    The INEEL contractors and their associated facilities are required to identify all liquid effluent discharges that may impact the environment at the INEEL. This liquid effluent information is then placed in the Liquid Effluent Inventory (LEI) database, which is maintained by the INEEL prime contractor. The purpose of the LEI is to identify and maintain a current listing of all liquid effluent discharge points and to identify which discharges are subject to federal, state, or local permitting or reporting requirements and DOE order requirements. Initial characterization, which represents most of the INEEL liquid effluents, has been performed, and additional characterization may be required in the future to meet regulations. LEI information is made available to persons responsible for or concerned with INEEL compliance with liquid effluent permitting or reporting requirements, such as the National Pollutant Discharge Elimination System, Wastewater Land Application, Storm Water Pollution Prevention, Spill Prevention Control and Countermeasures, and Industrial Wastewater Pretreatment. The State of Idaho Environmental Oversight and Monitoring Program also needs the information for tracking liquid effluent discharges at the INEEL. The information provides a baseline from which future liquid discharges can be identified, characterized, and regulated, if appropriate. The review covered new and removed buildings/structures, buildings/structures which most likely had new, relocated, or removed LEI discharge points, and at least 10% of the remaining discharge points.

  17. Diet - full liquid (United States)

    ... to your drinks Instant breakfast powder added to milk, puddings, custards, and milkshakes Strained meats (like the ones in baby food) added to broths Butter or margarine added to hot cereal and soups Sugar or syrup added to beverages Alternative Names Full liquid diet; Surgery - full liquid diet; ...

  18. Extraction of S- and N-Compounds from the Mixture of Hydrocarbons by Ionic Liquids as Selective Solvents

    Directory of Open Access Journals (Sweden)

    Beata Gabrić


    Full Text Available Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene, dibenzothiophene, and pyridine from two model solutions. The influences of hydrodynamic conditions, mass ratio, and number of stages were investigated. Increasing the mass ratio of ionic liquid/model fuel and multistage extraction promotes the desulfurization and denitrification abilities of the examined ionic liquids. All selected ionic liquids can be reused and regenerated by means of vacuum evaporation.

  19. Identification of genotypic variation for nitrogen response in potato (Solanum tuberosum) under low nitrogen input circumstances


    Tiemens-Hulscher, M.; Lammerts Van Bueren, E.; Struik, P. C.


    Nitrogen is an essential nutrient for crop growth. The demand for nitrogen in the potato crop is relatively high. However, in organic farming nitrogen input is rather limited, compared with conventional farming. In this research nine potato varieties were tested at three nitrogen levels. Genotypic variation for yield, leaf area index, period of maximum soil cover, sensitivity for N-shortage and nitrogen efficiency under low input circumstances was found. However, in these experiments varietie...

  20. Nitrogenous compounds stimulate glucose-derived acid production by oral Streptococcus and Actinomyces. (United States)

    Norimatsu, Yuka; Kawashima, Junko; Takano-Yamamoto, Teruko; Takahashi, Nobuhiro


    Both Streptococcus and Actinomyces can produce acids from dietary sugars and are frequently found in caries lesions. In the oral cavity, nitrogenous compounds, such as peptides and amino acids, are provided continuously by saliva and crevicular gingival fluid. Given that these bacteria can also utilize nitrogen compounds for their growth, it was hypothesized that nitrogenous compounds may influence their acid production; however, no previous studies have examined this topic. Therefore, the present study aimed to assess the effects of nitrogenous compounds (tryptone and glutamate) on glucose-derived acid production by Streptococcus and Actinomyces. Acid production was evaluated using a pH-stat method under anaerobic conditions, whereas the amounts of metabolic end-products were quantified using high performance liquid chromatography. Tryptone enhanced glucose-derived acid production by up to 2.68-fold, whereas glutamate enhanced Streptococcus species only. However, neither tryptone nor glutamate altered the end-product profiles, indicating that the nitrogenous compounds stimulate the whole metabolic pathways involving in acid production from glucose, but are not actively metabolized, nor do they alter metabolic pathways. These results suggest that nitrogenous compounds in the oral cavity promote acid production by Streptococcus and Actinomyces in vivo. © 2015 The Societies and Wiley Publishing Asia Pty Ltd.

  1. Enzymology and ecology of the nitrogen cycle. (United States)

    Martínez-Espinosa, Rosa María; Cole, Jeffrey A; Richardson, David J; Watmough, Nicholas J


    The nitrogen cycle describes the processes through which nitrogen is converted between its various chemical forms. These transformations involve both biological and abiotic redox processes. The principal processes involved in the nitrogen cycle are nitrogen fixation, nitrification, nitrate assimilation, respiratory reduction of nitrate to ammonia, anaerobic ammonia oxidation (anammox) and denitrification. All of these are carried out by micro-organisms, including bacteria, archaea and some specialized fungi. In the present article, we provide a brief introduction to both the biochemical and ecological aspects of these processes and consider how human activity over the last 100 years has changed the historic balance of the global nitrogen cycle.

  2. Biological Nitrogen Fixation on Legume

    Directory of Open Access Journals (Sweden)



    Full Text Available Nitrogen (N is one of the major limiting factors for crop growth and is required in adequate amount, due to its function as protein and enzyme components. In general, plants need sufficient nitrogen supply at all levels of growth, especially at the beginning of growth phase. Therefore, the availability of less expensive N resources would reduce the production cost. The increasing use of chemical fertilizer would probably disturb soil microorganisms, reduce the physical and chemical characteristics of soil because not all of N based fertilizer applied can be absorbed by the plants. Approximately only 50% can be used by crops, while the rest will be altered by microorganism into unavailable N for crops or else dissappear in the form of gas. Leguminous crops have the capacity to immobilize N2 and convert into the available N if innoculated with Rhizobium. The amount of N2 fixed varies depending on legume species and their environment.

  3. Interactions in ion pairs of protic ionic liquids: Comparison with aprotic ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Tsuzuki, Seiji, E-mail: [Research Initiative of Computational Sciences (RICS), Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Shinoda, Wataru [Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Miran, Md. Shah; Kinoshita, Hiroshi; Yasuda, Tomohiro; Watanabe, Masayoshi [Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)


    The stabilization energies for the formation (E{sub form}) of 11 ion pairs of protic and aprotic ionic liquids were studied by MP2/6-311G{sup **} level ab initio calculations to elucidate the difference between the interactions of ions in protic ionic liquids and those in aprotic ionic liquids. The interactions in the ion pairs of protic ionic liquids (diethylmethylammonium [dema] and dimethylpropylammonium [dmpa] based ionic liquids) are stronger than those of aprotic ionic liquids (ethyltrimethylammonium [etma] based ionic liquids). The E{sub form} for the [dema][CF{sub 3}SO{sub 3}] and [dmpa][CF{sub 3}SO{sub 3}] complexes (−95.6 and −96.4 kcal/mol, respectively) are significantly larger (more negative) than that for the [etma][CF{sub 3}SO{sub 3}] complex (−81.0 kcal/mol). The same trend was observed for the calculations of ion pairs of the three cations with the Cl{sup −}, BF{sub 4}{sup −}, TFSA{sup −} anions. The anion has contact with the N–H bond of the dema{sup +} or dmpa{sup +} cations in the most stable geometries of the dema{sup +} and dmpa{sup +} complexes. The optimized geometries, in which the anions locate on the counter side of the cations, are 11.0–18.0 kcal/mol less stable, which shows that the interactions in the ions pairs of protic ionic liquids have strong directionality. The E{sub form} for the less stable geometries for the dema{sup +} and dmpa{sup +} complexes are close to those for the most stable etma{sup +} complexes. The electrostatic interaction, which is the major source of the attraction in the ion pairs, is responsible for the directionality of the interactions and determining the magnitude of the interaction energy. Molecular dynamic simulations of the [dema][TFSA] and [dmpa][TFSA] ionic liquids show that the N–H bonds of the cations have contact with the negatively charged (oxygen and nitrogen) atoms of TFSA{sup −} anion, while the strong directionality of the interactions was not suggested from the simulation

  4. The adsorption of nitrogen oxides on crystalline ice

    Directory of Open Access Journals (Sweden)

    T. Bartels


    Full Text Available The partitioning of nitrogen oxides between ice and air is of importance to the ozone budget in the upper troposphere. In the present study, adsorption of nitrogen oxides on ice was investigated at atmospheric pressure using a chromatographic technique with radioactively labelled nitrogen oxides at low concentrations. The measured retentions solely depended on molecular adsorption and were not influenced by dimerisation, formation of encapsulated hydrates on the ice surface, dissociation of the acids, nor by migration into a quasi-liquid layer or grain boundaries. Based on the chromatographic retention and the model of thermo-chromatography, the standard adsorption enthalpy of -20 kJ mol-1 for NO, -22kJ mol-1 for NO2, -30kJ mol-1 for peroxyacetyl nitrate, -32kJ mol-1 for HON} and -44 kJ mol-1 for HNO3 was calculated. To perform those calculations within the model of thermo-chromatography, the standard adsorption entropy was calculated based on statistical thermodynamics. In this work, two different choices of standard states were applied, and consequently different values of the standard adsorption entropy, of either between -39 kJ mol-1 and -45kJ mol-1, or -164 kJ mol-1 and -169 kJ mol-1 for each nitrogen oxide were derived. The standard adsorption enthalpy was identical for both standard adsorption entropies and thus shown to be independent of the choice of standard state. A brief outlook on environmental implications of our findings indicates that adsorption on ice might be an important removal process of HNO3. In addition, it might be of some importance for HONO and peroxyacetyl nitrate and irrelevant for NO and NO2.

  5. Exploring the Fate of Nitrogen Heterocycles in Complex Prebiotic Mixtures (United States)

    Smith, Karen E.; Callahan, Michael P.; Cleaves, Henderson J.; Dworkin, Jason P.; House, Christopher H.


    A long standing question in the field of prebiotic chemistry is the origin of the genetic macromolecules DNA and RNA. DNA and RNA have very complex structures with repeating subunits of nucleotides, which are composed of nucleobases (nitrogen heterocycles) connected to sugar-phosphate. Due to the instability of some nucleobases (e.g. cytosine), difficulty of synthesis and instability of D-ribose, and the likely scarcity of polyphosphates necessary for the modern nucleotides, alternative nucleotides have been proposed for constructing the first genetic material. Thus, we have begun to investigate the chemistry of nitrogen heterocycles in plausible, complex prebiotic mixtures in an effort to identify robust reactions and potential alternative nucleotides. We have taken a complex prebiotic mixture produced by a spark discharge acting on a gas mixture of N2, CO2, CH4, and H2, and reacted it with four nitrogen heterocycles: uracil, 5-hydroxymethyluracil, guanine, and isoxanthopterin (2-amino-4,7-dihydroxypteridine). The products of the reaction between the spark mixture and each nitrogen heterocycle were characterized by liquid chromatography coupled to UV spectroscopy and Orbitrap mass spectrometry. We found that the reaction between the spark mixtUl'e and isoxanthopterin formed one major product, which was a cyanide adduct. 5-hydroxymethyluracil also reacted with the spark mixture to form a cyanide adduct, uracil-5-acetonitrile, which has been synthesized previously by reacting HCN with S-hydroxymethyluracil. Unlike isoxanthopterin, the chromatogram of the 5-hydroxymethyluracil reaction was much more complex with multiple products including spark-modified dimers. Additionally, we observed that HMU readily self-polymerizes in solution to a variety of oligomers consistent with those suggested by Cleaves. Guanine and uracil, the biological nucleobases, did not react with the spark mixture, even at high temperature (100 C). This suggests that there are alternative

  6. Evaluation of ionic liquid epoxy carbon fiber composites in a cryogenic environment (United States)

    Lyne, Christopher T.; Henry, Christopher R.; Kaukler, William F.; Grugel, R. N.


    A novel ionic liquid epoxy (ILE) was used to fabricate carbon fiber composite discs which were then subjected to biaxial strain testing in liquid nitrogen. The ILE composite showed a greater strain-to-failure at cryogenic temperatures when compared to a commercial epoxy. This result is likely an effect, as shown in micrographs, of the strong ILE bonding with the carbon fibers as well as it exhibiting plastic deformation at the fracture surface.

  7. Liquid marbles: Physics and applications

    Indian Academy of Sciences (India)

    hydrophobic. Abstract. Liquid marbles are formed by encapsulating microscale volume of liquid in a particulate sheath. The marble thus formed is robust and resists rupture if the particulate layer covers the entire volume of liquid and prevents ...

  8. Liquid Oxygen Thermodynamic Vent System Testing with Helium Pressurization (United States)

    VanDresar, Neil T.


    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

  9. Virtual Nitrogen Losses from Organic Food Production (United States)

    Cattell Noll, L.; Galloway, J. N.; Leach, A. M.; Seufert, V.; Atwell, B.; Shade, J.


    Reactive nitrogen (Nr) is necessary for crop and animal production, but when it is lost to the environment, it creates a cascade of detrimental environmental impacts. The nitrogen challenge is to maximize the food production benefits of Nr, while minimizing losses to the environment. The first nitrogen footprint tool was created in 2012 to help consumers learn about the Nr losses to the environment that result from an individual's lifestyle choices. The nitrogen lost during food production was estimated with virtual nitrogen factors (VNFs) that quantify the amount of nitrogen lost to the environment per unit nitrogen consumed. Alternative agricultural systems, such as USDA certified organic farms, utilize practices that diverge from conventional production. In order to evaluate the potential sustainability of these alternative agricultural systems, our team calculated VNFs that reflect organic production. Initial data indicate that VNFs for organic grains and organic starchy roots are comparable to, but slightly higher than conventional (+10% and +20% respectively). In contrast, the VNF for organic vegetables is significantly higher (+90%) and the VNF for organic legumes is significantly lower (-90%). Initial data on organic meat production shows that organic poultry and organic pigmeat are comparable to conventional production (both <5% difference), but that the organic beef VNF is significantly higher (+30%). These data show that in some cases organic and conventional production are comparable in terms of nitrogen efficiency. However, since conventional production relies heavily on the creation of new reactive nitrogen (Haber-Bosch, biological nitrogen fixation) and organic production primarily utilizes already existing reactive nitrogen (manure, crop residue, compost), the data also show that organic production contributes less new reactive nitrogen to the environment than conventional production (approximately 70% less). Therefore, we conclude that on a local

  10. [Identification of a high ammonia nitrogen tolerant and heterotrophic nitrification-aerobic denitrification bacterial strain TN-14 and its nitrogen removal capabilities]. (United States)

    Xin, Xin; Yao, Li; Lu, Lei; Leng, Lu; Zhou, Ying-Qin; Guo, Jun-Yuan


    A new strain of high ammonia nitrogen tolerant and heterotrophic nitrification-aerobic denitrification bacterium TN-14 was isolated from the environment. Its physiological and biochemical characteristics and molecular identification, performences of heterotrophic nitrification-aerobic, the abilities of resistance to ammonia nitrogen as well as the decontamination abilities were studied, respectively. It was preliminary identified as Acinetobacter sp. according to its physiological and biochemical characteristics and molecular identification results. In heterotrophic nitrification system, the ammonia nitrogen and total nitrogen removal rate of the bacterial strain TN-14 could reach 97.13% and 93.53% within 24 h. In nitrates denitrification system, the nitrate concentration could decline from 94.24 mg · L(-1) to 39.32 mg · L(-1) within 24 h, where the removal rate was 58.28% and the denitrification rate was 2.28 mg · (L · h)(-1); In nitrite denitrification systems, the initial concentration of nitrite could be declined from 97.78 mg · L(-1) to 21.30 mg x L(-1), with a nitrite nitrogen removal rate of 78.22%, and a denitrification rate of 2.55 mg · (L· h)(-1). Meanwhile, strain TN-14 had the capability of flocculant production, and the flocculating rate could reach 94.74% when its fermentation liquid was used to treat 0.4% kaolin suspension. Strain TN-14 could grow at an ammonia nitrogen concentration as high as 1200 mg · L(-1). In the aspect of actual piggery wastewater treatment by strain TN-14, the removal rate of COD, ammonia nitrogen, TN and TP cloud reached 85.30%, 65.72%, 64.86% and 79.41%, respectively. Strain TN-14 has a good application prospect in biological treatment of real high- ammonia wastewater.

  11. Bioconversion of nitrogen in an eco-technical system for egg production

    Directory of Open Access Journals (Sweden)

    A. Gencheva


    – k = 35.85 or 41.5% more than in fresh manure. When separated nitrogen is concentrated in the liquid fraction (k = 31.19, while in the solid phase k = 4.67 is established.

  12. Nitrogen-Doped Carbonaceous Materials for Removal of Phenol from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Magdalena Hofman


    Full Text Available Carbonaceous material (brown coal modified by pyrolysis, activation, and enrichment in nitrogen, with two different factor reagents, have been used as adsorbent of phenol from liquid phase. Changes in the phenol content in the test solutions were monitored after subsequent intervals of adsorption with selected adsorbents prepared from organic materials. Significant effect of nitrogen present in the adsorbent material on its adsorption capacity was noted. Sorption capacity of these selected materials was found to depend on the time of use, their surface area, and pore distribution. A conformation to the most well-known adsorption isotherm models, Langmuir, and Freundlich ones, confirms the formation of mono- and heterolayer solute (phenol coverage on the surface of the adsorbent applied herein. The materials proposed as adsorbents of the aqueous solution contaminants were proved effective, which means that the waste materials considered are promising activated carbon precursors for liquid phase adsorbents for the environmental protection.

  13. Environmental impact analysis of nitrogen cross-media metabolism: A case study of municipal solid waste treatment system in China. (United States)

    Wen, Zongguo; Bai, Weinan; Zhang, Wenting; Chen, Chen; Fei, Fan; Chen, Bin; Huang, Yi


    Municipal Solid Waste Treatment System (MSWTS) contributes a lot to urban metabolism optimization and pollution control of nitrogen. An analysis framework for cross-media metabolism of nitrogen was developed for MSWTS to study the systematic effects of nitrogen metabolism in MSWTS on ecosystem quality. Then cross-media distribution of pollutants was calculated in landfill, composting, incineration and anaerobic digestion, respectively. Sixty three percent to 82% of the original inputs ended up in the natural environment using the former three technologies (landfill, composting and incineration), which was attributed to cross-media migration. Anaerobic digestion should be highlighted due to its overall desirable removal efficiency. Critical processes related to nitrogen cross-media migration were identified to analyze the overall environmental impacts sensitivities. Positive effects emerged in liquid-solid interface migration of nitrogen through sewage collection and treatment technology processes, while the incineration flue gas treatment witnessed negative effects in gas-liquid interface migration. Overall, the environmental impact sensitivity levels of nitrogen cross-media migration under critical processes were as follows: incineration>landfill>composting>anaerobic digestion. Therefore, the environment is most sensitively affected by incineration and its processes. The present study is of great significance to optimize environmental management by shifting the management mode from single environmental medium quality control to systematic ecosystem quality improvement. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Liquid Nicotine Toxicity. (United States)

    Kim, Ji Won; Baum, Carl R


    E-cigarettes, also known as electronic nicotine delivery systems and electronic cigarettes, are advertised as a healthier alternative product to tobacco cigarettes despite limited data on the consequences of e-cigarette use. Currently, there are no US Food and Drug Administration or other federal regulations of e-cigarettes, and calls to poison control centers regarding liquid nicotine toxicity, especially in children, are on the rise. This article presents the background and mechanism of action of e-cigarettes as well as up-to-date details of the toxicity of liquid nicotine. We also present management strategies in the setting of liquid nicotine toxicity.

  15. Liquid crystals fundamentals

    CERN Document Server

    Singh, Shri


    Liquid crystals are partially ordered systems without a rigid, long-range structure. The study of these materials covers a wide area: chemical structure, physical properties and technical applications. Due to their dual nature - anisotropic physical properties of solids and rheological behavior of liquids - and easy response to externally applied electric, magnetic, optical and surface fields liquid crystals are of greatest potential for scientific and technological applications. The subject has come of age and has achieved the status of being a very exciting interdisciplinary field of scienti

  16. How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels. (United States)

    Balotf, Sadegh; Islam, Shahidul; Kavoosi, Gholamreza; Kholdebarin, Bahman; Juhasz, Angela; Ma, Wujun


    Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants.

  17. How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels.

    Directory of Open Access Journals (Sweden)

    Sadegh Balotf

    Full Text Available Nitrogen (N is one of the most important nutrients for plants and nitric oxide (NO as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE. This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3 treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants.

  18. Analysis of On-Board Oxygen and Nitrogen Generation Systems for Surface Vessels. (United States)


    electrical supply: all utilities (filter, heater , cooler, compressor, valves, solid state elec- tronics, monitor/command, converters, firefighting) are...explosion), liquid nitrogen ( suffocation , cold temperatures, etc.). A comprehensive analysis of expected hazards caused by the presence of LOX, LN, GOX...the designer and the user should review the application environment (e.g. open or in enclosure) to avoid a potential suffocation j hazard. (Appendix A

  19. Virginia No-Till Fact Sheet Series. Number Six, Nitrogen Fertilizer Sources and Properties


    Alley, Marcus M., 1947-; Thomason, Wade Everett; Woodward, Timothy


    The most commonly available nitrogen fertilizer sources used in Virginia are urea, liquid urea-ammonium nitrate (UAN) solution, and ammonium sulfate. Ammonium nitrate is also available in some areas but its use is low relative to urea and UAN solution. Understanding the properties of these fertilizers enables managers to make better decisions as to the most effective way to use these fertilizers as well as to make economic comparisons.

  20. Parallel artificial liquid membrane extraction

    DEFF Research Database (Denmark)

    Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine


    This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti......This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....

  1. Study of nitrogen two-phase flow pressure drop in horizontal and vertical orientation (United States)

    Koettig, T.; Kirsch, H.; Santandrea, D.; Bremer, J.


    The large-scale liquid argon Short Baseline Neutrino Far-detector located at Fermilab is designed to detect neutrinos allowing research in the field of neutrino oscillations. It will be filled with liquid argon and operate at almost ambient pressure. Consequently, its operation temperature is determined at about 87 K. The detector will be surrounded by a thermal shield, which is actively cooled with boiling nitrogen at a pressure of about 2.8 bar absolute, the respective saturation pressure of nitrogen. Due to strict temperature gradient constraints, it is important to study the two-phase flow pressure drop of nitrogen along the cooling circuit of the thermal shield in different orientations of the flow with respect to gravity. An experimental setup has been built in order to determine the two-phase flow pressure drop in nitrogen in horizontal, vertical upward and vertical downward direction. The measurements have been conducted under quasi-adiabatic conditions and at a saturation pressure of 2.8 bar absolute. The mass velocity has been varied in the range of 20 kg·m‑2·s‑1 to 70 kg·m‑2·s‑1 and the pressure drop data has been recorded scanning the two-phase region from vapor qualities close to zero up to 0.7. The experimental data will be compared with several established predictions of pressure drop e.g. Mueller-Steinhagen and Heck by using the void fraction correlation of Rouhani.

  2. Liquid for plugging wells

    Energy Technology Data Exchange (ETDEWEB)

    Chernysheva, T.L.; Bal' tser, V.V.; Shul' gina, V.A.


    The purpose of the invention is to increase the viscosity of liquid used for plugging wells. The goal is achieved by the fact that the liquid also contains commercial-grade glycerine and mono-ethanolamide, with the following relations between the components (wt.-%): carboxymethylcellulose, 58.7-69; surfactant, 0.3-0.7; commercial-grade glycerine, 30-40; monethanolamide, 0.3-1; the butethal P /SUB 12-14/2/ is contained in the liquid as the surfactant. The liquid was tested for its ability to plug up wells. For this purpose, a compound prepared from a mixture of 4-% carboxymethylcellulose, commercial-grade glycerine, monoethanolamide, and the butethal P /SUB 12-14// solution was tested for viscosity. The results of the studies are presented in a table.

  3. Liquid fuel cells

    National Research Council Canada - National Science Library

    Soloveichik, Grigorii L


    The advantages of liquid fuel cells (LFCs) over conventional hydrogen-oxygen fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety...

  4. Corporate governance and liquidity

    DEFF Research Database (Denmark)

    Farooq, Omar; Derrabi, Mohamed; Naciri, Monir


    difference in liquidity between the two periods. Furthermore, our results indicate that more than 50% of this difference between the two periods can be explained by operational and informational complexity of a firm – proxy for transparency. We argue that poor corporate governance mechanisms increase......This paper examines the impact of corporate governance mechanisms on liquidity in the MENA region, i.e. Morocco, Egypt, Saudi Arabia, United Arab Emirates, Jordan, Kuwait, and Bahrain. Using turnover as a proxy for liquidity, we document significant difference in liquidity between the pre......- and the post-crisis periods in the MENA region. In addition, our results show that bulk of this reduction in turnover can be explained due to weaknesses of corporate governance mechanisms. For example, that dividend payout ratio and choice of auditors – proxies for agency problems – can explain the entire...

  5. Liquid Modernity & Late Capitalism

    DEFF Research Database (Denmark)

    Hansen, Claus D.

    In Liquid Modernity, Bauman portrays Adorno and the rest of the early Frankfurt School as sociologists and thinkers belonging to the ‘heavy’ phase of modernity. In other words, they are deemed irrelevant to the discussion of current sociological time diagnoses and the purpose of critique under...... conditions of such liquid modernity. In this paper, I want to argue that this picture of Adorno is mistaken and extend the view proposed by Frederic Jameson that Adorno was not only the philosopher of 1990’s but is also very useful in the 2010’s. In fact, the critique of critical theory and emancipation...... as a crucial goal of such critique raised by Bauman in Liquid Modernity fails to acknowledge the complexity of Adorno’s theoretical apparatus. Adorno’s idea of pseudo-individualisation is laid out and compared to the critique Bauman points to with individualization processes in the liquid phase of modernity...

  6. Ionic liquids in tribology. (United States)

    Minami, Ichiro


    Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  7. Chiral separation by enantioselective liquid-liquid extraction

    NARCIS (Netherlands)

    Schuur, B.; Verkuijl, B. J. V.; Minnaard, A. J.; De Vries, J. G.; Heeres, H. J.; Feringa, B. L.


    The literature on enantioselective liquid-liquid extraction (ELLE) spans more than half a century of research. Nonetheless, a comprehensive overview has not appeared during the past few decades. Enantioselective liquid-liquid extraction is a technology of interest for a wide range of chemists and

  8. Seasonal Nitrogen Cycles on Pluto (United States)

    Hansen, Candice J.; Paige, David A.


    A thermal model, developed to predict seasonal nitrogen cycles on Triton, has been modified and applied to Pluto. The model was used to calculate the partitioning of nitrogen between surface frost deposits and the atmosphere, as a function of time for various sets of input parameters. Volatile transport was confirmed to have a significant effect on Pluto's climate as nitrogen moved around on a seasonal time scale between hemispheres, and sublimed into and condensed out of the atmosphere. Pluto's high obliquity was found to have a significant effect on the distribution of frost on its surface. Conditions that would lead to permanent polar caps on Triton were found to lead to permanent zonal frost bands on Pluto. In some instances, frost sublimed from the middle of a seasonal cap outward, resulting in a "polar bald spot". Frost which was darker than the substrate did not satisfy observables on Pluto, in contrast to our findings for Triton. Bright frost (brighter than the substrate) came closer to matching observables. Atmospheric pressure varied seasonally. The amplitudes, and to a lesser extent the phase, of the variation depended significantly on frost and substrate properties. Atmospheric pressure was found to be determined both by Pluto's distance from the sun and by the subsolar latitude. In most cases two peaks in atmospheric pressure were observed annually: a greater one associated with the sublimation of the north polar cap just as Pluto receded from perihelion, and a lesser one associated with the sublimation of the south polar cap as Pluto approached perihelion. Our model predicted frost-free dark substrate surface temperatures in the 50 to 60 K range, while frost temperatures typically ranged between 30 to 40 K. Temporal changes in frost coverage illustrated by our results, and changes in the viewing geometry of Pluto from the Earth, may be important for interpretation of ground-based measurements of Pluto's thermal emission.

  9. Liquid Crystal Airborne Display (United States)


    with the drive capability of the present state-of-the- art microm.ziiaturized integi ated circuits. The impact of microminiaturizing the drive circuits...7 Advantages /Disadvantages of Prior Art .........- 8 Performance of the Liquid Crystal Matrix Display . . .. 8 Liquid Crystal...Holographic HUD Light Source ...................... .... 99 Design of a Special Purpose Mercury Art - Plo.?hcr La np . 104 V LARGE SCALE INTEGRATION FOR DISPLAY

  10. Liquid Rocket Engine Testing (United States)


    Briefing Charts 3. DATES COVERED (From - To) 17 October 2016 – 26 October 2016 4. TITLE AND SUBTITLE Liquid Rocket Engine Testing 5a. CONTRACT NUMBER...298 (Rev. 8-98) Prescribed by ANSI Std. 239.18 Liquid Rocket Engine Testing SFTE Symposium 21 October 2016 Jake Robertson, Capt USAF AFRL... Rocket Lab Distribution A: Approved for Public Release; Distribution Unlimited. PA Clearance 16493 2Distribution A: Approved for Public Release

  11. Gas to liquids

    Energy Technology Data Exchange (ETDEWEB)

    Roche, Pat


    Sasol, a South African company, along with the Canadian company Talisman, are looking at gas to liquid process opportunities in North America. Sasol decided to launch a study into the feasibility of gas to liquid (GTL) operation in western Canada, and according to previous studies GTL would need a crude barrel price of $85 or higher combined with a gas price of $4 or less to be economical. Sasol is already operating a GTL plant in Qatar.

  12. [Reactive nitrogen and oxygen species]. (United States)

    Puzanowska-Tarasiewicz, Helena; Kuźmicka, Ludmiła; Tarasiewicz, Mirosław


    Reactive nitrogen species (RNS) and reactive oxygen species (ROS) are mainly free radicals which including non-paired electrons. They are constantly formed as side products of biological reactions. They are also generated directly and indirectly by the cells which were exposed to environmental stress, i.e., UV radiation, ionizing radiation, xenobioticts, light-absorbing compounds, e.g., porphyrines. These factors, which are a source of free radicals, initiate a significant signaling cascade inducing many changes in cells, such as cancerogenic transformation or cell death. Cells protect themselves against oxidative stress by means of antioxidative enzymes and compounds which in their structure have redox sensitive spots.

  13. Liquid developer jetting device

    Energy Technology Data Exchange (ETDEWEB)

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


    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.).

  14. Cold Helium Pressurization for Liquid Oxygen/Liquid Methane Propulsion Systems: Fully-Integrated Hot-Fire Test Results (United States)

    Morehead, R. L.; Atwell, M. J.; Melcher, J. C.; Hurlbert, E. A.


    Hot-fire test demonstrations were successfully conducted using a cold helium pressurization system fully integrated into a liquid oxygen (LOX) / liquid methane (LCH4) propulsion system (Figure 1). Cold helium pressurant storage at near liquid nitrogen (LN2) temperatures (-275 F and colder) and used as a heated tank pressurant provides a substantial density advantage compared to ambient temperature storage. The increased storage density reduces helium pressurant tank size and mass, creating payload increases of 35% for small lunar-lander sized applications. This degree of mass reduction also enables pressure-fed propulsion systems for human-rated Mars ascent vehicle designs. Hot-fire test results from the highly-instrumented test bed will be used to demonstrate system performance and validate integrated models of the helium and propulsion systems. A pressurization performance metric will also be developed as a means to compare different active pressurization schemes.

  15. Apple wine processing with different nitrogen contents

    Directory of Open Access Journals (Sweden)

    Aline Alberti


    Full Text Available The aim of this work was to evaluate the nitrogen content in different varieties of apple musts and to study the effect of different nitrogen concentrations in apple wine fermentation. The average total nitrogen content in 51 different apples juices was 155.81 mg/L, with 86.28 % of the values above 100 mg/L. The apple must with 59.0, 122.0 and 163.0 mg/L of total nitrogen content showed the maximum population of 2.05x 10(7; 4.42 x 10(7 and 8.66 x 10(7 cell/mL, respectively. Therefore, the maximum fermentation rates were dependent on the initial nitrogen level, corresponding to 1.4, 5.1 and 9.2 g/, respectively. The nitrogen content in the apple musts was an important factor of growth and fermentation velocity.



    Zhukova, Yaroslava; Petov, Pylyp; Mudrak, Tatyana


    Raw organic and conventional cow’s milk samples were analyzed for total nitrogen, non-protein nitrogen and milk urea content with the aim of evaluation of the different diets effect. Conventional milk contained higher level of total milk urea nitrogen as well as higher proportion in total nitrogen and non-protein nitrogen fraction. We detected that ratio of milk urea nitrogen to non-protein nitrogen is the most significant criterion for assessment of diet differences.

  17. Connection Between Dynamics and Thermodynamics of Liquids on the Melting Line (United States)


    viscosities and diffusion coefficients of simple monoatomic (argon, xenon, krypton) and diatomic (nitrogen, oxygen) liquids, as well as for a variety be strongly correlating [8], and accordingly density scaling should apply. Since metals are monoatomic , we anticipate that γ = . If this is the

  18. Transport Phenomena in Liquid Foams and Liquid Marble Colloids


    Attia, Joseph


    Liquid foams consist of randomly packed bubbles separated by a thin liquid fluid. They can be found in various industrial applications including separation processes, oil recovery, water treatment, food, and material processings. They are also being considered as coolant in heat exchangers systems for heat transfer enhancement compared with single-phase air. Similarly, liquid marbles, a phase inversion of liquid foams, consisting of a liquid core stabilized by closely packed solid hydrophobic...

  19. The nitrogen cycle in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Bange, H.W.; Naqvi, S.W.A.; Codispoti, L.A.

    scenario. The question marks indicate interactions yet to be quantified. External insolation forcing Climate Indian Ocean intermediate ?? H.W. Bange et al. / Progress in Oceanography 65 (2005) 145–158 155 Acknowledgements We acknowledge the helpful comments... elements including nitrogen (N) as highlighted in recent reviews of the oceanic nitrogen cycle by Capone (2000), Codispoti et al. (2001), and Zehr and Ward (2002). Within the oceans, the contribution of the Arabian Sea to biogeo- The nitrogen cycle...

  20. Nitrogen availability of biogas residues

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed Fouda, Sara


    The objectives of this study were to characterize biogas residues either unseparated or separated into a liquid and a solid phase from the fermentation of different substrates with respect to their N and C content. In addition, short and long term effects of the application of these biogas residues on the N availability and N utilization by ryegrass was investigated. It is concluded that unseparated or liquid separated biogas residues provide N at least corresponding to their ammonium content and that after the first fertilizer application the C{sub org}:N{sub org} ratio of the biogas residues was a crucial factor for the N availability. After long term application, the organic N accumulated in the soil leads to an increased release of N.

  1. Nitrogen on Mars: Insights from Curiosity (United States)

    Stern, J. C.; Sutter, B.; Jackson, W. A.; Navarro-Gonzalez, Rafael; McKay, Chrisopher P.; Ming, W.; Archer, P. Douglas; Glavin, D. P.; Fairen, A. G.; Mahaffy, Paul R.


    Recent detection of nitrate on Mars indicates that nitrogen fixation processes occurred in early martian history. Data collected by the Sample Analysis at Mars (SAM) instrument on the Curiosity Rover can be integrated with Mars analog work in order to better understand the fixation and mobility of nitrogen on Mars, and thus its availability to putative biology. In particular, the relationship between nitrate and other soluble salts may help reveal the timing of nitrogen fixation and post-depositional behavior of nitrate on Mars. In addition, in situ measurements of nitrogen abundance and isotopic composition may be used to model atmospheric conditions on early Mars.

  2. Experimental nitrogen dioxide poisoning in cattle

    Energy Technology Data Exchange (ETDEWEB)

    Cutlip, R.C.


    Experimental nitrogen dioxide inhalation has been reported to produce signs and lesions typical of field cases of bovine pulmonary adenomatosis (BPA) as described by Monlux et al, and Seaton. Similar lesions have been produced in mice and guinea pigs. These studies were conducted because of the similarities between silo-filler's disease of man, caused by nitrogen dioxide, and BPA. Since previous studies involved inadequate numbers of cattle, a more critical evaluation of the effects of nitrogen dioxide was needed. This project was designed to study the clinical and pathologic alterations induced in cattle by repeated exposure to nitrogen dioxide gas.

  3. Effect of Gas- and Liquid-injection Methods on Formation of Bubble and Liquid Slug at Merging Micro T-junction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jun Kyoung [Kyungnam Univ., Changwon (Korea, Republic of); Lee, Chi Young [Pukyong Nat’l Univ., Busan (Korea, Republic of)


    In the present experimental study, the effect of gas- and liquid-injected methods on the formation of bubble and liquid slug at the merging micro T-junction of a square microchannel with dimensions 600 μm × 600 μm was investigated. Nitrogen and water were used as test fluids. The superficial velocities of the liquid and gas were in the range of 0.05 - 1 m/s, and 0.1 - 1 m/s, respectively, where the Taylor flow was observed. The bubble length, liquid slug length, bubble velocity, and bubble generation frequency were measured by analyzing the images captured using a high-speed camera. Under similar inlet superficial velocity conditions, in the case of gas injection to the main channel at the merging T-junction (T{sub g}as-liquid), the lengths of the bubble and liquid slug were longer, and the bubble generation frequency was lower than in the case of liquid injection to the main channel at the merging T-junction (T{sub l}iquid-gas). On the other hand, in both cases, the bubble velocity was almost the same. The previous correlation proposed using experimental data for T{sub l}iquid-gas had predicted the present experimental data of bubble length, bubble velocity, liquid slug length, and bubble generation frequency for T{sub g}as-liquid to be ~24%, ~9%, ~39%, ~55%, respectively.

  4. Asset Pricing with Liquidity Risk


    Acharya, Viral V.; Lasse Heje Pedersen


    This Paper solves explicitly a simple equilibrium asset pricing model with liquidity risk – the risk arising from unpredictable changes in liquidity over time. In our liquidity-adjusted capital asset pricing model, a security’s required return depends on its expected liquidity as well as on the covariances of its own return and liquidity with market return and market liquidity. In addition, the model shows how a negative shock to a security’s liquidity, if it is persistent, results in low con...

  5. Theoretical prediction of the effect of heat transfer parameters on cooling rates of liquid-filled plastic straws used for cryopreservation of spermatozoa. (United States)

    Sansinen, M; Santos, M V; Zaritzky, N; Baez, R; Chirife, J


    Heat transfer plays a key role in cryopreservation of liquid semen in plastic straws. The effect of several parameters on the cooling rate of a liquid-filled polypropylene straw when plunged into liquid nitrogen was investigated using a theoretical model. The geometry of the straw containing the liquid was assimilated as two concentric finite cylinders of different materials: the fluid and the straw; the unsteady-state heat conduction equation for concentric cylinders was numerically solved. Parameters studied include external (convection) heat transfer coefficient (h), the thermal properties of straw manufacturing material and wall thickness. It was concluded that the single most important parameter affecting the cooling rate of a liquid column contained in a straw is the external heat transfer coefficient in LN2. Consequently, in order to attain maximum cooling rates, conditions have to be designed to obtain the highest possible heat transfer coefficient when the plastic straw is plunged in liquid nitrogen.

  6. Cryogenic Adsorption of Nitrogen and Carbon Dioxide in Activated Carbon (United States)

    Shen, Fuzhi; Liu, Huiming; Xu, Dong; Zhang, Hengcheng; Lu, Junfeng; Li, Laifeng


    Activated carbon have been used for a long time at low temperature for cryogenic applications. The knowledge of adsorption characteristics of activated carbon at cryogenic temperature is essential for some specific applications. However, such experimental data are very scare in the literature. In order to measure the adsorption characteristics of activated carbon under variable cryogenic temperatures, an adsorption measurement device was presented. The experiment system is based on the commercially available PCT-pro adsorption analyzer coupled to a two-stage Gifford McMahon refrigerator, which allows the sample to be cooled to 4.2K. Cryogenic environment can be maintained steadily without the cryogenic liquid through the cryocooler and temperature can be controlled precisely between 5K and 300K by the temperature controller. Adsorption measurements were performed in activated carbon for carbon dioxide and nitrogen and the adsorption isotherm were obtained.

  7. Numerical investigation on pulsating heat pipes with nitrogen or hydrogen (United States)

    Y Han, D.; Sun, X.; Gan, Z. H.; Y Luo, R.; Pfotenhauer, J. M.; Jiao, B.


    With flexible structure and excellent performance, pulsating heat pipes (PHP) are regarded as a great solution to distribute cooling power for cryocoolers. The experiments on PHPs with cryogenic fluids have been carried out, indicating their efficient performances in cryogenics. There are large differences in physical properties between the fluids at room and cryogenic temperature, resulting in their different heat transfer and oscillation characteristics. Up to now, the numerical investigations on cryogenic fluids have rarely been carried out. In this paper, the model of the closed-loop PHP with multiple liquid slugs and vapor plugs is performed with nitrogen and hydrogen as working fluids, respectively. The effects of heating wall temperature on the performance of close-looped PHPs are investigated and compared with that of water PHP.

  8. On nitrogen condensation in hypersonic nozzle flows: Numerical method and parametric study

    KAUST Repository

    Lin, Longyuan


    A numerical method for calculating two-dimensional planar and axisymmetric hypersonic nozzle flows with nitrogen condensation is developed. The classical nucleation theory with an empirical correction function and the modified Gyarmathy model are used to describe the nucleation rate and the droplet growth, respectively. The conservation of the liquid phase is described by a finite number of moments of the size distribution function. The moment equations are then combined with the Euler equations and are solved by the finite-volume method. The numerical method is first validated by comparing its prediction with experimental results from the literature. The effects of nitrogen condensation on hypersonic nozzle flows are then numerically examined. The parameters at the nozzle exit under the conditions of condensation and no-condensation are evaluated. For the condensation case, the static pressure, the static temperature, and the amount of condensed fluid at the nozzle exit decrease with the increase of the total temperature. Compared with the no-condensation case, both the static pressure and temperature at the nozzle exit increase, and the Mach number decreases due to the nitrogen condensation. It is also indicated that preheating the nitrogen gas is necessary to avoid the nitrogen condensation even for a hypersonic nozzle with a Mach number of 5 operating at room temperatures. © 2013 Springer-Verlag Berlin Heidelberg.

  9. Operation with three liquid phases in a staged liquid-liquid contactor

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, R.A.; Ziegler, A.A.; Wigeland, R.A.; Bane, R.W.; Steindler, M.J.


    Operation with three liquid phases was demonstrated in a staged liquid-liquid contactor. The possibility that three liquid phases could be handled in a liquid-liquid contactor normally used with two liquid phases was initially established using a laboratory batch test. Tht three liquid phases were obtained using a thorium flow sheet having high concentrations of both acid and thorium. To analyze the batch test, the concept of a dimensionless dispersion number for use with two liquid phases was extended so that it could be applied to three liquid phases. Based on the batch tests, continuous flow tests were run in a staged liquid-liquid contactor used for solvent extraction. A critical factor in the success of these tests was determining the position of the liquid-liquid interface in the contactor. Thus, a contactor was used which allows the position of the liquid-liquid interface to be adjusted. Actual three-phase operation was demonstrated using a 4-cm annular centrifugal contactor, albeit with a somewhat greater (3 to 4 vol. %) aqueous-phase contamination of the organic exit stream than normal (< 1 vol. %).

  10. Effect of nitrogen supply on leaf growth, leaf nitrogen economy and photosynthetic capacity in potato

    NARCIS (Netherlands)

    Vos, J.; Putten, van der P.E.L.


    Literature reports show little effect of nitrogen supply on radiation use efficiency in potato and in other dicotyledonous C3 species. This paper tests the hypothesis that potato reduces leaf size rather than leaf nitrogen concentration and photosynthetic capacity when nitrogen is in short supply.

  11. Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Harmens, H., E-mail: [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Norris, D.A., E-mail: [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Cooper, D.M., E-mail: [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Mills, G., E-mail: [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Steinnes, E., E-mail: [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Kubin, E., E-mail: [Finnish Forest Research Institute, Kirkkosaarentie 7, 91500 Muhos (Finland); Thoeni, L., E-mail: [FUB-Research Group for Environmental Monitoring, Alte Jonastrasse 83, 8640 Rapperswil (Switzerland); Aboal, J.R., E-mail: [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Alber, R., E-mail: [Environmental Agency of Bolzano, 39055 Laives (Italy); Carballeira, A., E-mail: [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Coskun, M., E-mail: [Canakkale Onsekiz Mart University, Faculty of Medicine, Department of Medical Biology, 17100 Canakkale (Turkey); De Temmerman, L., E-mail: [Veterinary and Agrochemical Research Centre, Tervuren (Belgium); Frolova, M., E-mail: [Latvian Environment, Geology and Meteorology Agency, Riga (Latvia); Gonzalez-Miqueo, L., E-mail: [Univ. of Navarra, Irunlarrea No 1, 31008 Pamplona (Spain)


    In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations ({>=}1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km x 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r{sup 2} = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: > Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. > Moss concentrations were compared with EMEP modelled nitrogen deposition. > The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha{sup -1} y{sup -1}. > Linear relationships were found with measured nitrogen deposition in some countries. > Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

  12. The nitrogen footprint tool network: a multi-institution program to reduce nitrogen pollution (United States)

    Anthropogenic sources of reactive nitrogen have local and global impacts on air and water quality and detrimental effects on human and ecosystem health. This paper uses the nitrogen footprint tool (NFT) to determine the amount of nitrogen (N) released as a result of institutional...

  13. Nitrogen and energy metabolism of sows during several reproductive cycles in relation to nitrogen intake

    NARCIS (Netherlands)

    Everts, H.


    By feeding the same diet during pregnancy and lactation sows are fed above the nitrogen requirement during pregnancy due to the relatively high nitrogen requirement during lactation. For feeding closer to the requirements at least two diets are needed: one diet with a low nitrogen content

  14. A nitrogen dioxide delivery system for biological media. (United States)

    Skinn, Brian T; Deen, William M


    Nitrogen dioxide is formed endogenously via the oxidation of NO by O(2) or O(2)(-) and from NO(2)(-) via peroxidases, among other pathways. This radical has many potential biological targets and its concentration, like that of NO and other reactive nitrogen species, is thought to be elevated at sites of inflammation. To investigate the specific cytotoxic or mutagenic effects of NO(2), it is desirable to be able to maintain its concentration at constant, predictable, and physiological levels in cell cultures, in the absence of NO. To do this, a delivery system was constructed in which NO(2)-containing gas mixtures contact a liquid within a small (110 ml) stirred reactor. In such gas mixtures NO(2) is present in equilibrium with its dimer, N(2)O(4). The uptake of NO(2) and N(2)O(4) was characterized by measuring the accumulation rates of NO(2)(-) and NO(3)(-), the stable products of N(2)O(4) hydrolysis, in buffered aqueous solutions. In some experiments NO(2)-reactive 2,2'-azino-bis(3-ethyl-benzothiazoline-6-sulfonate) (ABTS) was included and formation of the stable ABTS radical was measured. A reaction-diffusion model was developed that predicts the accumulation rates of all three products to within 15% for gas-phase concentrations of NO(2) spanning 3 orders of magnitude. The model also provides estimates for the NO(2) concentration in the liquid. This system should be useful for exposing cells to NO(2) concentrations similar to those in vivo. Copyright © 2013. Published by Elsevier Inc.

  15. 21 CFR 862.1770 - Urea nitrogen test system. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

  16. Implications of liquid-liquid distribution coefficients to mineral-liquid partitioning (United States)

    Ryerson, F. J.; Hess, P. C.


    In order to evaluate the influence of a silicate liquid structure on mineral-liquid partitioning, element partitioning data is obtained for coexisting anhydrous immiscible granitic and ferrobasaltic magmas. It is found that: (1) mineral-liquid distribution coefficients indicate the competition of crystal and liquid for cation incorporation, (2) increased polymerization of the residual liquid during crystal-liquid fractionation increases the mineral-liquid distribution coefficients for high-charge-density cations, (3) incompatible element ratios of low- and high-charge-density cations may vary during crystal-liquid fractionation because of changes in the melt composition and structure, (4) relative solubilities of REE's in melts do not vary with melt polymerization, (5) the changes of Sm/Eu ratios during crystal-liquid fractionation depend on the melt composition, and (6) minor components and volatiles can significantly influence the silicate melt structure and the mineral-liquid distribution coefficients.

  17. Annular Air Leaks in a liquid hydrogen storage tank (United States)

    Krenn, AG; Youngquist, RC; Starr, SO


    Large liquid hydrogen (LH2) storage tanks are vital infrastructure for NASA, the DOD, and industrial users. Over time, air may leak into the evacuated, perlite filled annular region of these tanks. Once inside, the extremely low temperatures will cause most of the air to freeze. If a significant mass of air is allowed to accumulate, severe damage can result from nominal draining operations. Collection of liquid air on the outer shell may chill it below its ductility range, resulting in fracture. Testing and analysis to quantify the thermal conductivity of perlite that has nitrogen frozen into its interstitial spaces and to determine the void fraction of frozen nitrogen within a perlite/frozen nitrogen mixture is presented. General equations to evaluate methods for removing frozen air, while avoiding fracture, are developed. A hypothetical leak is imposed on an existing tank geometry and a full analysis of that leak is detailed. This analysis includes a thermal model of the tank and a time-to-failure calculation. Approaches to safely remove the frozen air are analyzed, leading to the conclusion that the most feasible approach is to allow the frozen air to melt and to use a water stream to prevent the outer shell from chilling.

  18. Laser imaging in liquid-liquid flows (United States)

    Abidin, M. I. I. Zainal; Park, Kyeong H.; Voulgaropoulos, Victor; Chinaud, Maxime; Angeli, Panagiota


    In this work, the flow patterns formed during the horizontal flow of two immiscible liquids are studied. The pipe is made from acrylic, has an ID of 26 mm and a length of 4 m. A silicone oil (5cSt) and a water/glycerol mixture are used as test fluids. This set of liquids is chosen to match the refractive indices of the phases and enable laser based flow pattern identification. A double pulsed Nd:Yag laser was employed (532mm) with the appropriate optics to generate a laser sheet at the middle of the pipe. The aqueous phase was dyed with Rhodamine 6G, to distinguish between the two phases. Experiments were carried out for mixture velocities ranging from 0.15 to 2 m/s. Different inlet designs were used to actuate flow patterns in a controlled way and observe their development downstream the test section. A static mixer produced dispersed flow at the inlet which separated downstream due to enhanced coalescence. On the other hand, the use of a cylindrical bluff body at the inlet created non-linear interfacial waves in initially stratified flows from which drops detached leading to the transition to dispersed patterns. From the detailed images important flow parameters were measured such as wave characteristics and drop size. Project funded under the UK Engineering and Physical Sciences Research Council (EPSRC) Programme Grant MEMPHIS.

  19. The formation of nitrogen compounds at gasification/pyrolysis condition

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerkman, E.; Nilsson, Torbjoern; Stroemberg, B. [TPS Termiska Processer AB, Nykoeping (Sweden)


    A kinetic model by which it is possible to determine reactions constants for the formation/destruction of hydrogen cyanide and ammonia from fuel-N during pyrolysis/gasification conditions in presence of an internal catalyst is here presented, together with the possibilities to experimentally support the model with data. The experiments were performed in a small fixed bed quarts reactor, the bed materials were CaO and iron doped CaO. The fuel used was a liquid mixture of pyridine, ethylene glycol and formic acid (25 mole-% C, 49 mole-% H, 24 mole-% 0 and 1.8 mole-% of N). The product gas was analysed for NH{sub 3}, HCN, NO, CO, CO{sub 2}, CH{sub 4} and C{sub 2}H{sub 4} with an FTIR. For some of the experiments a gas chromatograph with double thermal conductivity detectors (TCD) was used to measure the nitrogen gas formation. Changing the contact time with the iron doped CaO gave significant changes in mainly ammonia and nitrogen monoxide concentrations. The decomposition of hydrogen cyanide has also been studied, showing that no ammonia was formed from HCN during the experimental conditions used 26 refs, 8 figs, 1 appendix

  20. How important are internal temperature gradients in french straws during freezing of bovine sperm in nitrogen vapor? (United States)

    Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J


    The subject of present work was to predict internal temperature gradients developed during freezing of bovine sperm diluted in extender, packaged in 0.5 ml French plastic straws and suspended in static liquid nitrogen vapor at -100 degree C. For this purpose, a mathematical heat transfer model previously developed to predict freezing times (phase change was considered) of semen/extender packaged in straw was extended to predict internal temperature gradients during the cooling/freezing process. Results showed maximum temperature differences between the centre and the periphery of semen/extender "liquid" column was 1.5 degree C for an external heat transfer coefficient, h = 15 W per (m(2) K), and only 0.5 degree C for h = 5 W per (m(2) K). It is concluded that if a thermocouple wire were inserted in a 0.5 ml plastic straw to monitor the freezing process in nitrogen vapor, its radial position would have little importance since expected internal gradients may be safely neglected. This finding facilitates the interpretation of freezing rates in 0.5 ml plastic straws immersed in nitrogen vapor over liquid nitrogen, a widely used method for cryopreservation of bovine spermatozoa.